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LIQUID SUPPLY METHOD, SYSTEM,
INK CONTAINER, CARTRIDGE AND
REPLENISHING CONTAINER AND
HEAD CARTRIDGE USAHLE WITH SYSTEM
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a liquid
supply method and a liquid supply system using a
negative pressure to supply liquid to an outside, and
more particularly to a liquid supply method usable
with a liquid ejection recording apparatus which
effects printing on recording material using a
recording head to which liquid is supplied, a liquid
supply system, an exchange liquid accommodating
container and head cartridge usable with such a
system.
Conventionally, a liquid supply method using
a negative pressure for supplying liquid to the
outside is known in an ink jet recording apparatus
field, wherein for example an ink container for
permitting supply of liquid to an ink ejection head
with a negative pressure, and wherein the ink
container is made integral with the recording head
((head cartridge). The head cartridge is classified
into a type wherein the recording head and the ink
container (ink accommodating portion) are normally
integral, and a type wherein the recording means and
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the ink accommodating portion are separate, which are
both separable relative to the recording device, and
are made integral when they are used.
In such a liquid supply system, the easiest
way of producing the negative pressure is to use
capillary force of a porous material. The ink
container of this type is provided With a porous
material such as sponge which is accommodated
preferably under compression and which occupies the
entirety of the inside of the container, and with an
air vent for permitting smooth ink supply by
introduction of the air during the printing. However,
this type involves a problem that ink accommodation
efficiency per unit voltage is low since the porous
member is used to retain the ink. EP0580433 which has
been assigned to the assignee of this application has
proposed an ink container including a negative
pressure producing material chamber, an ink
accommodating chamber (reservoir) and a fluid
communication part therebetween, wherein the ink
accommodating chamber is substantially hermetically
sealed, and the negative pressure producing material
chamber is open to the ambience. EP0581531 also
proposes a structure wherein the above-described o is
exchangeable.
Such an ink container is advantageous in that
air is permitted go into the ink accommodating chamber
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with discharge of the ink from the ink accommodating
chamber into the negative pressure producing material
chamber (air-liquid exchanging operation), so that ink
can be supplied to the outside with a substantially
constant negative pressure during the air-liquid
exchanging operation.
EP0738605 which has been assigned to the
assignee of this application proposes a liquid
accommodating container including a casing having a
substantially prism configuration, and a liquid
accommodating portion which is deformable with
discharge of the liquid therefrom said accommodating
portion having an outer shape similar or equivalent to
an inner shape of the casing, wherein in each side of
the prism-like shape, the thickness at the corner
portions of the side is smaller than the central
portion thereof. In the liquid accommodating
container, the accommodating portion deforms or
contracts with the discharge of the liquid (without
air-liquid exchange) so that liquid is supplied with
the negative pressure. This container is advantageous
in that position of the ink container is not limited
as compared with an ink containing bladder which is
conventional. Additionally, since the ink is directly
retained (substantially without use of porous
material), the ink accommodation efficiency is high.
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SUN~IARY OF THE INVENTION
The ink container of the type having the
negative pressure producing material chamber and the
ink accommodating chamber has a fixed accommodation
space. In order to discharge the ink therefrom into
the negative pressure producing material chamber, air-
liquid exchange is used, by which the air is
introduced into the ink accommodating chamber.
Therefore, when the ink is supplied out into the
negative pressure producing material chamber, the
corresponding amount of the aid is introduced, so that
ink accommodating chamber contains both of the air and
the ink. The air may expands due to the ambient
condition change (temperature variation during 24
hours) with the result that ink is discharged into the
negative pressure producing material chamber from the
ink accommodating chamber. Therefore, a buffer space
has to be provided in the negative pressure producing
member or material in consideration of a practically
maximum volume determined by the expansion and the
resulting amount of ink motion in various conditions.
In the conventional air-liquid exchanging operation,
the ink discharge from the ink accommodating chamber
into the negative pressure producing material chamber
is directly interrelated with the introduction of the
air through the communicating portion, and therefore,
when a large amount of the ink is discharged from the
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negative pressure producing material chamber to the
outside (liquid ejecting head) in a short period of
time, the ink supply from the ink accommodating
chamber into the negative pressure producing material
chamber with the air-liquid exchanging operation is
unlikely to follow the abrupt ink consumption.
Accordingly, it is a principal object of the
present invention to provide a liquid supply method, a
liquid supply system, an ink container and an ink jet
cartridge wherein the ink is contained in the negative
pressure producing material chamber and the ink
accommodating chamber (reservoir) and wherein the
volume of the buffer space required by the negative
pressure producing material chamber can be reduced
even in view of various conditions, can be reduced,
and the ink supply is carried out with a stable
negative pressure during use of the ink in the ink
accommodating chamber while permitting large expansion
of the air introduced by the air-liquid exchange.
It is another object of the present invention
to provide a liquid supply system and a liquid
container usable with the system wherein the ink
accommodating chamber (liquid accommodating container)
is exchangeable in addition to or independently of the
first object.
It is a further object of the present
invention to provide a related devices such as a head
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cartridge related with the liquid supply method and
the liquid supply system. The inventors have analyzed
in detail the ink accommodating chamber containing the
air in an ink container having the negative pressure
producing material chamber, the ink accommodating
chamber and the communication port therebetween. The
supply of the ink from the ink accommodating chamber
into the negative pressure producing material chamber
occurs in interrelation with the introduction of the
air.
The expansion of the air in the ink
accommodating chamber is unavoidable, but the
inventors have considered allowing the expansion of
the air in the ink accommodating chamber.
It is a further object of the present
invention to provide a According to an aspect of the
present invention, there is provided a liquid supply
method comprising a step of preparing a negative
pressure producing material chamber, including a
liquid supply portion for permitting supply of the
liquid to an outside and an air vent for fluid
communication with ambience, for accommodating a
negative pressure producing member for retaining the
liquid; a step of preparing a liquid containing
chamber having a liquid containing portion for
accommodating the liquid, said liquid containing
portion forming a substantially sealed space except
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for fluid communication with the negative pressure
producing material chamber; a first liquid supply step
of permitting supply of the liquid to the outside by
permitting movement of the liquid into said negative
pressure producing material chamber from said liquid
containing portion without introduction of the air
into the liquid containing chamber with a negative
pressure while permitting decrease of a volume of said
liquid containing portion; a second liquid supply
step, after said first liquid supply step, of
permitting supply of the liquid to the outside by
permitting movement of the liquid into said negative
pressure producing material chamber from said liquid
containing portion with introduction of the air into
the liquid containing portion.
According to this method, the liquid
containing portion deforms while maintaining a balance
in the negative pressure with the negative pressure
producing member. Therefore, even if the air expands
in the liquid containing portion due to the ambient
condition change, the liquid containing portion
restores its shape upon an abrupt change so that
influence of the change can be decreased. If the
change is not abrupt, the influence of the expansion
can be decreased by both of the negative pressure
producing member and the liquid containing portion
while the balance is eventually maintained with the
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negative pressure producing member. Therefore, the
voltage of the buffer space in the negative pressure
producing material chamber can be reduced even in view
of various use condition.
In the second liquid supply process, the air
is introduced into the liquid containing portion, so
that liquid in the liquid containing portion is used
up substantially without an unusable remaining amount
ink, and the negative pressure difference between at
the time of the start of the liquid discharge from the
liquid containing portion and at the time of.the end
thereof, can be smaller than that when the liquid
containing portion alone is used as a negative
pressure producing container. As compared with the
conventional type ink container having the negative
pressure producing material chamber, the ink
accommodating chamber and the communication port
therebetween, the allowance to the air expansion is
larger. Even if a large amount of the ink is consumed
in a short period of time, the liquid supply from the
liquid containing portion into the negative pressure
producing material chamber is smooth since the liquid
containing portion is deformable. Therefore, the ink
supply is stabilized when the ink in the liquid
containing portion is consumed. According to another
aspect of the present invention, there is provided a
liquid supply system, using a liquid supply container
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including a liquid containing portion for
accommodating liquid in a sealed space; a negative
pressure producing material container, which
accommodating container is detachably mountable
relative to the liquid supply container and which is
capable of effecting air-liquid exchange wherein air
is introduced into said liquid containing portion, and
the liquid is discharged through a communicating
portion communicating with said liquid accommodating
portion; the improvement comprising: said liquid
containing portion of said liquid supply container is
capable of producing a negative pressure while
deforming; and wherein when the liquid supply
container is mounted to said negative pressure
producing material chamber, the liquid is permitted to
move from said liquid containing portion into said
negative pressure producing material chamber.
According to this system, even if the
accommodating container for the negative pressure
producing material does not contain the liquid in the
neighborhood of the communicating portion to the
liquid accommodating container, the liquid can be
moved from the liquid accommodating container into the
negative pressure producing member using the capillary
force in the negative pressure producing material
chamber upon the mounting of the liquid accommodating
container to the negative pressure producing material
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chamber, so that liquid in the exchanged liquid
accommodating container can be assuredly used by the
simple mounting, irrespective of the liquid retaining
state of the negative pressure producing member
adjacent the connecting portion. Thus, a practical
liquid supply system with stabilized liquid supply can
be provided.
By movement in a part of the liquid in the
liquid containing portion into the negative pressure
producing material container upon the connection, the
liquid.containing portion is deformed, and therefore,
influence of the expansion of the air in the liquid
containing portion due to the ambient condition change
can be eased. The present invention provides an ink
container and an ink jet cartridge usable with the
liquid supply method and the liquid supply system.
More particularly, according to a further
aspect of the present invention, there is provided a
liquid container, comprising a negative pressure
producing material chamber, including a liquid supply
portion for permitting supply of the liquid to an
outside and an air vent for fluid communication with
ambience, for accommodating a negative pressure
producing member for retaining the liquid; a liquid
containing chamber having a liquid containing portion
for accommodating the liquid, said liquid containing
portion forming a substantially sealed space except
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for fluid communication with the negative pressure
producing material chamber; wherein said liquid
containing portion deforms with discharge of the
liquid therefrom while producing a negative pressure.
The ink jet cartridge provided by the present
invention comprises the above-described ink container
and a recording head for effecting recording by
ejecting the liquid to the outside. Further, the
present invention provides an exchange liquid
accommodating container usable with the liquid supply
system.
More particularly, there is provided a liquid
accommodating container detachably mountable relative
to a negative pressure producing material container,
having a liquid supply portion for supplying liquid to
an outside and an air vent for fluid communication
with ambience, for accommodating a negative pressure
producing member for retaining the liquid, comprising
a liquid containing portion for accommodating the
liquid, which forms a substantially sealed space
except for fluid communication with the negative
pressure producing material chamber; and sealing means
for sealing said communicating portion relative to
said negative pressure producing material chamber.
Furthermore, there is provided a liquid
accommodating container detachably mountable relative
to a negative pressure producing material container,
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having a liquid supply portion for supplying liquid to
an outside and an air vent for fluid communication
with ambience, for accommodating a negative pressure
producing member for retaining the liquid, comprising
a liquid containing portion for accommodating the
liquid, which forms a substantially sealed space
except for fluid communication with the negative
pressure producing material chamber; and a casing
having an inner shape equivalent or similar to an
outer shape of said liquid containing portion and
having an air vent for introducing the ambience;
sealing means for sealing said communicating portion
relative to said negative pressure producing material
chamber.
The present invention is suitably applicable
to a head cartridge used in an ink jet recording
field.
More particularly, there is provided a head
cartridge comprising a recording head for ejecting the
liquid; a negative pressure producing material
chamber, including a liquid supply portion for
permitting supply of the liquid to said recording head
and an air vent for fluid communication with ambience,
for accommodating a negative pressure producing member
for retaining the liquid; a liquid containing chamber
having a liquid containing portion for accommodating
the liquid, said liquid containing portion forming a
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substantially sealed space except for fluid
communication with the negative pressure producing
material chamber; and wherein said liquid containing
portion deforms with discharge of the liquid therefrom
while producing a negative pressure; wherein said
recording head and said negative pressure producing
material chamber are integral with each other.
A further aspect of the present invention
provides a further method. More particularly, it
provides a liquid supply method comprising a step of
preparing a negative pressure producing material
chamber, including a liquid supply portion for
permitting supply of the liquid to an outside and an
air vent for fluid communication with ambience, for
accommodating a negative pressure producing member for
retaining the liquid; a step of preparing a liquid
containing chamber having a liquid containing portion
for accommodating the liquid, said liquid containing
portion forming a substantially sealed space except
for fluid communication with the negative pressure
producing material chamber; a step of moving the
liquid from said liquid containing portion into said
negative pressure producing material chamber without
introduction of air into said liquid containing
chamber with a negative pressure while permitting
decrease of a volume of said liquid containing
portion.
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According to this method, the liquid in the
liquid containing portion is usable without
introduction of the air into the liquid containing
portion, and therefore, even if the limitation to the
inside volume of the liquid containing chamber is
eased, change of the ambience is accommodatable.
In this specification, the negative pressure
producing material container and the liquid
accommodating container are generally used where they
are separable from each other, and the negative
pressure producing material chamber and the liquid
containing chamber are used when they are separable ar
not separable.
The region not filled with the liquid
adjacent the air vent of the first chamber means a
part the negative pressure producing member not filled
with the ink as well as the space not having the
negative pressure producing member (buffer portion).
These and other objects, features and
advantages of the present invention will become more
app~.rent upon a consideration of the following
description of the preferred embodiments of the present
invention taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic illustration of an
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ink container applicable with a liquid supply system
according to a first embodiment of the present
invention, wherein (a) is a perspective view thereof,
and (b) is a sectional view thereof.
Figure 2 is a schematic illustration of an
ink accommodating chamber and an accommodating chamber
for a negative pressure producing material when they
are connected.
Figure 3 is a schematic illustration for
illustrating a first ink supply state in the ink
container shown in Figure 1.
Figure 4 is a schematic illustration for
illustrating a second ink supply state (air-liquid
exchanging state) in the ink container shown in Figure
1 .
Figure 5 is a schematic illustration
illustrating a change in the container when the liquid
is discharged after the second ink supply state shown
in Figure 1.
Figure 6 is an illustration showing a
relation between the amount of ink discharge and the
negative static pressure at an ink supply in the ink
container shown in Figure 1.
Figure 7, (a) is a detailed illustration of a
negative pressure curve shown in Figure 6; (b) shows a
change of an amount of ink discharge from an ink
accommodating portion and an amount of introduced air
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into the ink accommodating portion with time when the
air is continuously discharged.
Figure 8 is a detail illustration of an A
region shown in Figure 7.
Figure 9 is an illustration of operation of
an ink container as regards the A region shown in
Figure 7.
Figure 10 is a detail illustration as to B
region shown in Figure 7.
Figure 11 is an illustration of operation of
an ink container as to B region shown in Figure 7.
Figure 12 illustrates operation during
exchange of the ink accommodating chamber.
Figure 13 is an illustration of a mechanism
of stabilized liquid retention when an ambient
condition is changed in the ink container shown in
Figure 1.
Figure 14 is an illustration of an amount of
ink discharging when the pressure in the ink container
shown in Figure 1 is reduced, wherein (a) is an
illustration of a relation between a volume of an
initial space of the ink accommodating chamber before
the pressure reduction and an amount of ink
discharging upon pressure reduction, and (b) show an
amount of ink discharge from the ink accommodating
portion and a change, with time, of the volume of the
ink accommodating portion when the ambience pressure
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of the container is changed from ambient pressure to P
atm. (0<P<1) (pressure-reduced state).
Figure 15 is a schematic illustration of an
ink container usable with the liquid supply system of
the present invention according to a second
embodiment, wherein (a) is a perspective view thereof,
and (b) is a sectional view thereof.
Figure 16 is a schematic illustration of an
ink container usable with a liquid supply system
according to a third embodiment.
Figure ~7 is a schematic illustration of a
modified example of an ink container usable with a
liquid supply system of the present invention.
Figure 18 is a schematic illustration of
pressing the ink accommodating portion.
Figure 19 is a schematic sectional view of a
modified example of an ink container usable with the
liquid supply system of the present invention.
Figure 20 is a schematic sectional view of a
modified example of an ink container usable with a
liquid supply system of the present invention.
Figure 21 is a schematic illustration of an
example of an ink jet recording apparatus usable with
a liquid supply system of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the accompanying drawings, the
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embodiments of the present invention will be
described. In the following descriptions, ink is
taken as an example of the liquid usable with the
liquid supply method and the liquid supply system
according to the present invention, but the present
invention is not limited to the ink but is usable with
processing liquid to be applied on the recording
material in the ink jet recording field, for example.
(First embodiment)
Figure 1 is a schematic illustration of an
ink container applicable with a liquid supply system
according to a first embodiment of the present
invention, wherein (a) is a perspective view thereof,
and (b) is a sectional view thereof.
The ink container 1 comprises an
accommodating chamber for the negative pressure
producing material 10 and an ink accommodating chamber
50, and the ink accommodating chamber 50 is separable
from the negative pressure producing material chamber
10 through a communication tube(air-liquid exchange
passage) 14. The negative pressure producing
material chamber 10 a casing member 11 having an ink
supply port 12 for supplying the ink (or processing
liquid or the like) into an outside means such as a
recording head 60 for effecting recording by ejecting
liquid through an ejection outlet 61, a negative
pressure producing member or material 13 of porous
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member or material such as polyurethane foam
accommodated therein, and a communication tube(air-
liquid exchange passage) 14, contacted to the negative
pressure generating member, for introducing liquid
from the second chamber. The casing 11 comprises an
ambience introducing groove 17, on an inside of the
communication tube, for promoting air-liquid exchange
which will be described hereinafter, an air vent 15
for fluid communication between the ambience and the
negative pressure producing member accommodated
therein, end there is provided a buffer portion 16 in
the form of a rib projected from the inner surface of
the casing adjacent the air vent 15. In the
embodiment, the air-liquid exchange passage 14 is
contacted to the negative pressure producing member
13, and the end thereof communicates with the air
introducing groove 17, so that smooth liquid supplying
operation which will be described hereinafter is
accomplished.
On the other hand, the ink accommodating
chamber 50 comprises a casing member(outer wall) 51
constituting a chamber, and ink accommodating portion
53, constituted by a wall(innex~ wall) 54 having an
inner surface similar to or equivalent to the inner
surface of the casing member, for accommodating the
ink therein, an ink discharging outlet 52
communicating with the air-liquid exchange passage 14
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of the accommodating chamber for the negative pressure
producing material, for discharging the liquid from
the liquid containing portion 53 into the negative
pressure producing material chamber. In this
embodiment, an unshown seal member such as an O-ring
is provided at a connecting portion between the ink
discharging outlet 52 and the air-liquid exchange
passage 14, by which the ink leakage and the
introduction of the ambience through the connecting
portion, is prevented. The seal member is
satisfactory if it is provided at one of the ink
accommodating chamber and the negative pressure
producing material chamber, or it may be provided at
each of them to enhance the sealing property. It may
be provided independently of the ink accommodating
chamber and the negative pressure producing material
chamber, and it may be engaged with the connecting
portions of them upon necessity. The inner wall 54
has a flexibility, and the ink accommodating portion
53 is deformable with the discharge of the ink
accommodated therein. The inner wall 54 has a welded
portion(pinch-off portion) 56, and the inner wall is
supported on the outer wall with engagement
therebetween at the welded portion. The outer wall
is provided with an ambience communication port 55 to
permit introduction of the ambience to between the
inner wall and the outer wall.
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In Figure 1 and the subsequent cross-
sectional Figures, the hatched portion indicates the
region of the negative pressure producing member
retaining the ink. The cross-hatched portion
indicates the ink contained in the space such as the
ink accommodating portion, the air introducing groove
and the air-liquid exchange passage. The ink
accommodating chamber of this embodiment is defined by
6 flat surfaces which constitute a substantially
rectangular parallelopiped configuration, to which a
cylindrical ink discharging outlet 52 is added in the
form of a curved surface, and the maximum area side of
the rectangular parallelopiped configuration is
indirectly shown in Figure 1. The thickness of the
internal wall surface 53 is thinner in the portion
constituting the apex portions, which will be called
corner portions (including the rounded corner with
small radius of curvature) than the central region of
each of the sides of the rectangular parallelopiped
shape, and the thickness gradually decreases from the
central region of each of the sides toward the corner
portions, and the configuration is convex inwardly of
the ink accommodating portion. The direction is the
same as the direction of deformation of the sides, so
that deformation is promoted, as will be described
hereinafter.
Each of the corner portions of the inner wall
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is constituted by three sides, so that strength of the
entirety of the corner portions of the inner wall is
greater than that of the central regions. As seen
from an extension of the sides, since the thickness of
the corner portions is smaller than of the central
region, movement of the sides are permitted. It is
desirable that portions constituting the corner
portions of the inner walls have substantially
equivalent thicknesses. Since Figure 1 is relatively
schematic, there is a space between the outer wall 51
of the ink accommodating chamber and the inner wall 52
thereof, but they may be contacted to each other or
spaced from each other, if they are separable.
The ink accommodating chamber of the ink
container may be of an exchangeable structure relative
to the negative pressure producing material chamber.
Referring to Figure 2, the description will be made as
to the states of the respective chambers when the ink
accommodating chamber is connected to the negative
pressure producing material chamber. Figure 2 shows
an example of changes of each of the chambers in a
connecting operation between the ink accommodating
chamber and the negative pressure producing material
chamber of the ink container shown in Figure 1, suffix
1 indicates that Figure is a sectional view in the
same direction as with Figure 1, (b), and suffix 2
indicates that Figure is a sectional view (A-A) of the
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liquid containing chamber shown in Figure 1, (b).
Figure 2(a1), (a2) show the states of the
negative pressure producing material chamber and the
ink accommodating chamber before the connection
therebetween. The ink discharging outlet 52 of the
liquid containing chamber 50 is provided with a
sealing means 57 (for example film) for preventing
discharge of the ink accommodated in the ink
accommodating portion, so that ink accommodating
portion of the liquid containing chamber is maintained
sealed against the atmosphere. The inner wall 54
constituting the ink accommodating portion is formed
such that it is extended along the inner surface
configuration of the casing(outer wall) 51 and that
corner portion of the inner wall is close to the
corner portion of the outer wall. This state is
called here " initial state". The ink accommodating
portion may contain an amount of the ink which is
slightly smaller than the maximum capacity thereof,
since then the ink is more assuredly prevented from
leaking out due to the temperature change and/or
pressure change, when the sealing means is unsealed.
In view of the standpoint of ambient condition change,
the amount of the air accommodated in the ink
accommodating portion before the connection to the
negative pressure producing material chamber, is
desirably very small. In order to decrease the
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amount of air accommodated in the ink accommodating
portion, a liquid injection method may be used, as
disclosed in Japanese Laid-open Patent Application No.
HEI- 10-175311.
On the other hand, in Figure 2(a1), the
negative pressure producing member of the negative
pressure producing material chamber retains the ink in
a part thereof. In Figure 2(a1), the interface of the
ink accommodated in the negative pressure producing
member is that in the case of it being lower than the
air introducing groove, and the air introducing groove
is in fluid communication with the ambience through
the negative pressure producing member.
Here, the amount of the ink accommodated in
the negative pressure producing member is dependent on
the amount of the ink accommodated in the negative
pressure producing member when the ink accommodating
chamber is exchanged, which will be described
hereinafter, and therefore, it may be different
slightly, and it is not inevitable that ink is
retained in the uniform state as shown in the Figure.
The air introducing groove and the air-liquid exchange
passage are not required to be filled with the liquid,
and may contain the air as shown in Figure 2(a1). As
shown in Figure 2(b1) and (b2), the ink accommodating
chamber is connection to the negative pressure
producing material chamber. At this time, the ink
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moves as shown by an arrow in Figure 2(b1) until the
pressures in the negative pressure producing material
chamber and the ink accommodating chamber becomes
equal to each other, and as shown in Figures 2, (c1)
and 2(c2), the balanced state is established with the
pressure at the ink supply port 12 being negative.
This state is called " state at start of use". The
detailed disclosure will be made as to the ink
movement until the balanced state is reached. As
shown in Figure 2(b1), when the air-liquid exchange
passage 14 of the negative pressure producing material
chamber is inserted into the ink discharge port of the
ink accommodating chamber, the sealing means 57 is
unsealed. The connecting portion is sealed by the
above-described seal means at this time, so that ink
does not leak through the connecting portion, or the
ambience is directly introduced into the ink
accommodating chamber through the connecting portion,
and therefore, the ink accommodating portion is in a
substantially hermetically sealed state except for the
air-liquid exchange passage 14. Then, the ink in the
ink accommodating portion 53 flows into the air-liquid
exchange passage 14, and an ink path is established
between the negative pressure producing material
chamber and the negative pressure producing member 13.
When the ink path is established, the ink movement
from the ink accommodating portion to the negative
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pressure producing member is started as shown in
Figure 2(b1) by the capillary force of the negative
pressure producing member, by which the interface
(level of liquid) of the negative pressure producing
member rises. The inner wall 54 tends to deform from
the central portion of the major side (maximum area
side) in a direction of decrease of the volume of the
ink accommodating portion 53. Here, the outer wall
51 functions to retard displacement of the corner
portions of the inner wall 54, and therefore, the ink
accommodating portion receives the force due to the .
ink consumption and rebounding force toward the
initial state (Figure 2(a1), (a2)), so that negative
pressure is generated in accordance with the degree of
deformation without abrupt change. The space between
the inner wall and the outer wall is in fluid
communication with the ambience through the ambience
communication port 55, so that air is introduced into
between the inner wall 54 and the outer wall 51 in
accordance with the deformation.
Even if the air is present in the air-liquid
exchange passage 14 in Figure 2(a1), the ink in the
ink accommodating portion is contacted to the negative
pressure producing member by which an ink path is
formed, and therefore, the ink accommodating portion
deforms with the discharge of the ink, so that air
easily moves into the ink accommodating portion 53.
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As regards the ink introduction into the air
introducing groove, the ink is supplied thereinto when
the capillary force of the air introducing groove is
larger than the negative pressure generated by the ink
accommodating portion, as in this embodiment. After
the start of the ink movement, the ink is supplied
into the negative pressure producing member, and then,
as shown in Figure 2, (c1), the ink is filled up to
above the top end portion of the ambience introduction
groove, so that fluid communication of the ambience
introduction groove with the ambience is shut. Then,
the ink accommodating chamber receives and discharges
the ink and the air only through the negative pressure
producing material chamber, so that ink further m4ves
so that negative static pressure in the air-liquid
exchange passage of the ink accommodating chamber and
the negative static pressure in the air-liquid
exchange passage of the negative pressure producing
material chamber.
In the state shown in Figure 2(c1), the
negative pressure in the negative pressure producing
material chamber when the communication of the
ambience introduction groove with the ambience is
shut, is larger than the negative pressure in the ink
accommodating chamber, a further ink movement occurs
from the ink accommodating chamber into the negative
pressure producing material chamber until the negative
CA 02396784 2002-09-05
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pressures of them becomes equal, by which the amount
of the ink retained in the negative pressure producing
member in the negative pressure producing material
chamber increases.
As described in the foregoing, the movement
of the ink from the ink accommodating chamber to the
negative pressure producing material chamber when the
ink accommodating chamber and the negative pressure
producing material chamber are connected, is carried
out without introduction of the air into the ink
accommodating chamber through the negative pressure
producing member. The negative static pressures in
the respective chambers in the balanced state, is
properly selected so that ink does not leak out of a
liquid ejection recording means(unshown) such as a
recording head connected to the ink supply port,
depending on the nature of the liquid ejection
recording means connected thereto (Figure 6 a) by one
skilled in the art. The lower limit of the amount of
the ink which is movable from the ink accommodating
portion, is the amount of the ink when the ink supply
is carried out into the negative pressure producing
member up to the upper limit level of the air
introducing groove (air-liquid interface negative
pressure producing member which will be described
hereinafter), and the upper limit is the amount up to
the complete ink filling into the negative pressure
CA 02396784 2002-09-05
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producing member. The amount of the ink moving to
the negative pressure producing member on the basis of
the amounts of the upper limit and the lower limit of
the ink in consideration of the variation of the
amount of the ink retained in the negative pressure
producing member before the connection. Hy doing so,
the material and the thickness of the ink
accommodating portion can be properly selected for the
negative pressure producing member on the basis of the
negative pressure value a in the balanced state.
Since the.amount of the ink retained in the negative
pressure producing member before the connection is not
constant, a part of the negative pressure producing
member may remain unsupplied with the ink even if the
balanced state is.reached as shown in Figure 2(c1) and
Figure 2(c2). Such a part can be used as a buffer
region which functions together with the buffer
portion, when the temperature and/or the pressure
varies, which will be described hereinafter.
On the contrary, if there is a liability that
pressure of the ink supply part when the balanced
state is reached, is positive due to the amount
variation, the suction recovery is carried out by
suction recovery means, which will be described
hereinafter and which is provided in the main assembly
of the liquid ejection recording device, is used to
discharge a small amount of the ink.
CA 02396784 2002-09-05
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The establishment of the ink path in the air-
liquid exchange passage upon the connecting operation,
may be effected using a mechanical impact given at the
time of the connecting action. For example, the ink
accommodating portion is pressurized by for example
pressing the casing of the ink accommodating portion,
as shown in Figure 18. Alternatively, the ink
accommodating portion is placed under a slight
negative pressure state, and by the ink accommodating
portion being brought into fluid communication with
the ambience through the air introducing groove upon
the connection, the air in the air-liquid exchange
passage is promoted to move into the ink accommodating
portion using deformation of the ink accommodating
portion by the variation of the pressure. With such
use of the impact, a part of the air in the passage
may move into the ink accommodating portion, depending
on the configuration of the air-liquid exchange
passage and/or the presence or absence of the air in
the passage before the connection, but such a slight
movement of the air into the ink accommodating portion
is permissible.
Referring to Figures 3-6, the description
will be made as to an example of states of the ink
container when the liquid is consumed by the recording
head connected to the ink container in the state at
start of use shown in Figures 2, (c1), (c2). Figures
CA 02396784 2002-09-05
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3-5 show an example of the changes of the ink
accommodating chamber and the negative pressure
producing material chamber with the consumption of the
liquid from the ink container, in the order of Figure
3, (a)-(c), Figure 4, (a)-(c) and Figure 5, (a)-(c),
wherein suffix 1 indicates the sectional plane which
is the same as that of Figure 1, (b); suffix 2
indicates the sectional plane A-A of the liquid
containing chamber in Figure 1, (b). Figure 6
illustrates a relation between the ink discharge
amount of the ink container shown in Figure 1 and the
negative pressure of the ink supply port, wherein the
abscissa represents an ink discharge amount from the
ink supply port to the outside, and the ordinate is a
negative pressure(negative static pressure) of the ink
supply port. In Figure 6, the change of the negative
pressure shown in Figures 2-5 is indicated by arrow.
In this embodiment, the ink supply operation
can be understood in the three modes, more
particularly, before the start of air-liquid
exchanging operation shown fn Figure 3, during
(mainly) air-liquid exchanging operation shown in
Figure 4 and after air-liquid exchanging operation
shown in Figure 5. In the following, the respective
operations are described in detail using the Figures.
(1) Before air-liquid exchanging operation
In Figure 3(a1), (a2), the ink container is
CA 02396784 2002-09-05
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mounted to the recording head. In the state at start
of use, the negative static pressure in the air-liquid
exchange passage of the ink accommodating chamber and
the negative static pressure in the air-liquid
exchange passage of the negative gressure producing
material chamber are equal to each other. In the case
of the ink accommodating chamber which is of a n
exchangeable type as shown in Figure 1, when the ink
accommodating chamber is exchanged after the ink is
used up to the state shown in Figure 2(a1) (the detail
will be described hereinafter deferring to Figure 6),
the ink accommodating portion is slightly deformed
inwardly, as described hereinbefore.
When the ink consumption is started through
the ink supply port 12 to the recording head 60, both
of the ink contained in the ink accommodating portion
and the negative pressure producing member are
consumed while the balance is maintained between the
increasing negative static pressures in the ink
accommodating portion and the negative pressure
producing member, as shown in Figure 3(b1), (b2).
This is called " first ink supply state ".
In this state, the liquid level in the
negative pressure producing member in the negative
pressure producing material chamber lowers with the
consumption of the ink through the ink supply port,
and the central gortions of the ink accommodating
CA 02396784 2002-09-05
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portion stably deforms inwardly.
In the sides adjacent to the major sides
(maximum area sides) in this embodiment, the portion
not having the pinch-off portion starts deformation
and separates from the outer wall earlier than the
portion having the pinch-off portion 104, in order to
reach the balance in the negative pressure between the
ink accommodating portion and the negative pressure
producing member. Here, the pinch-off portion 56
functions in effect as one of deformation limiting
portions against the inner wall 54. Thus, opposite
major sides of the ink accommodating portion deform
substantially simultaneously with the discharge of the
ink, so that stabilized deformation is accomplished.
This first ink supply state continues until
the air is introduced to the ink accommodating portion
through the air-liquid exchange passage as shown in
Figure 3(c1), (c2). The negative static pressure
change relative to the amount of the ink discharge
through the ink supply port from the state of Figure
3(a1), (a2) to the state of Figure 3(c1), (c2), is
such that it is substantially proportional to the
amount of the ink discharge, and the negative static
pressure gradually rises, as indicated by A in Figure
6.
The example has been described in brief, and
further detail will be described hereinafter.
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(2) During air-liquid exchanging operation
When the ink is further discharged, the
introduction of the air into the ink accommodating
portion starts as shown in Figure 3(c1), (c2). This
is called " air-liquid exchange state" or " second ink
supply state". In this state, as shown in Figure
4(a1), (a2) and Figure 4(b1), (b2), the liquid level
of the negative pressure producing member is
substantially constant(air-liquid interface) at the
top end portion of the air introducing groove. With
the consumption of the ink by the recording head, the
air is supplied from the air vent 15 through the air
introducing groove 17 and the air-liquid exchange
passage 14 into the ink accommodating chamber in
accordance with the consumption amount of the ink,
with which the ink is supplied into the negative
pressure producing member of the negative pressure
producing material chamber through the air-liquid
exchange passage. On the other hand, the ink
accommodating portion maintains the negative pressure
balance by the deformation thereof, so that air is
introduced with the discharge of the ink, and
maintains the configuration upon the air-liquid
exchange.
Therefore, the change of the negative static
pressure relative to the amount of the ink discharge
through the ink supply port in the air-liquid exchange
CA 02396784 2002-09-05
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state, substantially does not occur (substantially
constant negative static pressure) as indicated by B
in Figure 6, thus supplying the ink to the liquid
ejection recording means with stability. However,
Figure 6 is schematic, and the negative pressure is
not strictly constant in the air-liquid exchange
region. In the ink container of the present
invention, the ink accommodating chamber per se can be
contributable to the generation of the negative
pressure by the deformation of the ink accommodating
portion. When the ink is discharged continuously in
the air-liquid exchange state, a time difference may
frequently occur between the discharge of the liquid
from the ink accommodating portion and the
introduction of the air through the air-liquid
exchange path, as will be described hereinafter. The
time difference can be a cause of the negative
pressure variation, which however is tolerable in the
case of the ink jet recording apparatus.
When the air-liquid exchange path has a
degree of length as in this embodiment, the bubble of
the air-liquid exchange stagnates in the air-liquid
exchange path, and the bubble moves into the ink
accommodating portion when the amount thereof reaches
a certain level, depending on the kind of the ink.
This is also a cause of the negative pressure
variation upon the movement of the bubble, but the
CA 02396784 2002-09-05
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variation is tolerable when the liquid container is
used with an ink jet recording apparatus. This is
also the air-liquid exchange state.
When the bubbles tend to stagnate in the air-
s liquid exchange path, the air-liquid exchange path may
be temporarily kept plugged by the bubble even if the
ink level in the ink accommodating portion lowers
beyond the top end portion of the air-liquid exchange
path as shown in Figure 4(c1), (c2). In this state,
if, for example, the bubble despairs, and the ink
accommodating portion becomes temporarily in complete
fluid communication with the ambience, the ink
accommodating portion deforms more toward the initial
state than in the air-liquid exchange state shown in
Figure 4(bl)and 4(b2). Hut, when it is plugged by
the bubble, the ink is moved from the ink
accommodating portion into the negative pressure
producing material chamber in place of feeding of a
new bubble into the air-liquid exchange path, as if
the air-liquid exchange state were carried out.
Therefore, the state of Figure 4(c1), (c2) is included
in the air-liquid exchange state in the present
invention if the negative pressure in the ink
container is substantially within a range of the
negative pressure of the other part of Figure 4.
In the foregoing, the air-liquid exchanging
operation of the ink container has been described, but
CA 02396784 2002-09-05
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in the case of the deformable ink accommodating
chamber as in this invention, the operation during the
air-liquid exchange is not limited to the above.
In the conventional non-deformable ink
accommodating chamber, the ink is supplied into the
negative pressure producing member immediately with
the introduction of the ambience into the ink
accommodating chamber. When the ink accommodating
chamber is deformable, the ink may be supplied into
the negative pressure producing member without the
introduction of the ambience into the ink
accommodating chamber. On the contrary, the ink may
not be supplied into the negative pressure producing
member immediately after the introduction of the
ambience into the ink accommodating chamber with the
consumption of the ink. This depend on the negative
pressure balance between the displacement of the ink
accommodating chamber and the negative pressure
producing material chamber. Further detailed
description will be made as to this, hereinafter, but
it should be noted that timing of the air-liquid
exchanging operation may be different from that in the
conventional ink container, and by the time difference
between the ink discharge from the ink accommodating
portion and the introduction of the air into the ink
accommodating portion upon the air-liquid exchange,
the stable ink supply is more reliable because of the
CA 02396784 2002-09-05
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buffer effect and the timing deviation even upon
external factors such as abrupt ink consumption,
ambient condition change, vibration.
(3) After air-liquid exchanging operation
When the ink is further discharged through
the ink supply port, the ink level in the ink
accommodating portion becomes lower than the upper end
of the air introducing groove, so that ink
accommodating portion becomes in complete fluid
communication with the air-liquid exchange path, as
shown in Figure 5(a1), (a2). At this time, the ink
accommodating portion deforms more toward the initial
state than in the air-liquid exchange state by the
communication with the ambience. However, even if
the inside pressure becomes the ambient pressure, the
configuration does not completely restores, and it is
in a slightly deformed state. In this embodiment,
the air-liquid exchange path has a large diameter, and
therefore, a small amount of the ink remaining in the
ink accommodating portion is absorbed by the negative
pressure producing member with the result of rising of
the liquid level in the negative pressure producing
member, so that negative pressure temporarily lowers.
Thereafter, the air-liquid exchange path is sealed by
the ink in the negative pressure producing material,
the ink is consumed similarly to the air-liquid
exchanging operation described hereinbefore.
CA 02396784 2002-09-05
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When the liquid level in the negative
pressure producing member slightly lowers beyond the
top end of the air introducing groove, the pressure in
the ink accommodating chamber is described as becoming
the atmospheric pressure immediately, but this is an
example of the action in the embodiment of the present
invention. Further detailed description will be made
hereinafter.
When the ink is substantially completely
consumed from the ink accommodating portion, the ink
remaining in the negative pressure producing material
chamber is consumed as shown in Figure 5(c1), (c2).
Normally, when the ink container is placed on a
carriage, the ink in the ink accommodating chamber is
completely absorbed in the negative pressure producing
member due to the vibration during the carriage
scanning. Hut, it is preferable that ink accommodating
chamber is inclinedly mounted such that supply port
takes a lower position with respect to the direction
of gravity. The change of the negative pressure
relative to the amount of the ink discharge through
the ink supply port in the state after the air-liquid
exchanging operation, is such that negative pressure
increases in proportion to the amount of the ink
discharge, as indicated by C in Figure 6. After this
state is reached, even if the ink accommodating
chamber is demounted, the ink leakage is not liable
CA 02396784 2002-09-05
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through the air-liquid exchange passage 14 or the ink
discharging outlet 52, and therefore, the ink
accommodating chamber is demounted, and a new ink
accommodating chamber is prepared as shown in Figure
2(a1), (a2). Even when the ink is further consumed
beyond the state shown in Figure 5(c1), (c2) so that
negative pressure producing member adjacent. the air-
liquid exchange path does not retain the ink, the
negative pressure producing member adjacent the air-
liquid exchange path which is an ink supply path can
be filled with the ink with certainty, since when the
ink path is established by the exchanging operation
described in the foregoing, the ink accommodating
portion deforms with the discharge of the ink.
In the foregoing, the liquid supplying
operation of the ink container in this embodiment
(Figure 1) has been described.
Thus, in the example of the ink consuming
operation, when the ink accommodating chamber is
connected with the negative pressure producing
material chamber, the ink moves until the pressures of
negative pressure producing material chamber and the
ink accommodating chamber becomes equal so that state
at start of use is established. When the ink
consumption by the liquid ejection recording means is
started thereafter, the ink is consumed both from the
ink accommodating portion and the negative pressure
CA 02396784 2002-09-05
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producing member while the rising negative static
pressures are balanced therebetween. Thereafter, the
air-liquid exchange state occurs wherein the ink is
discharged with a substantially constant negative
pressure while the air-liquid interface of the
negative pressure producing member is maintained by
the introduction of the air into the ink accommodating
portion, and finally, the ink remaining in the
negative pressure producing material chamber is
consumed.
Thus, there is a step in which the ink is
used from the ink accommodating portion without the
introduction of the ambience into the ink
accommodating portion, so that limitation to the
inside volume of the liquid accommodating container in
the ink supply process (first ink supply state) is
only by the air introduced into the ink accommodating
portion in the connection. As a result, the
limitation to the inside volume of the ink
accommodating chamber can be reduced without influence
to the accommodation of the ambient condition change.
In the structure of the present invention,
the air-liquid exchanging operation can be effected at
different timing from that in the air-liquid exchange
of the prior art, the ink supply is possible in other
than normal state.
According to the present invention, the ink
CA 02396784 2002-09-05
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can be substantially completely consumed from the ink
accommodating chamber, and in addition, the air-liquid
exchange passage may contain the air when the ink
container is exchanged, and the ink accommodating
chamber can be exchanged irrespective of the amount of
the ink retained in the negative pressure producing
member. Therefore, the ink accommodating chamber is
easily exchangeable without use of the remaining
amount detecting mechanism.
As shown in Figure 6, in order that negative
pressure rises in proportion to the amount of the ink
discharge (A), and thereafter, it is substantially
constant (B), and then, the negative pressure rises in
proportion to the ink discharge amount (C), it is
desirable that ambience introduction occurs, that is,
the state shifts from A to H before opposing parallel
sides of the ink accommodating portion are brought
into contact. This is because the ratio of the
negative pressure change relative to the amount of the
ink discharge in the ink accommodating chamber is
different between before and after the opposing
maximum area sides are contacted.
With respect to the first embodiment, the ink
supply performance of the ink container has be
checked. A negative pressure producing member having
a pore size of approx 60 / inch is placed in the
negative pressure producing material chamber having
CA 02396784 2002-09-05
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inner dimensions of 48mm x 46mm x lOmm approx, and the
air-liquid exchange path is in the form of a hollow
pipe having an inner diameter of approx 7mm. The
negative pressure producing material chamber is
connected to an ink accommodating chamber including an
outer wall of shock resistant polystyrene (HIPS) resin
material having a maximum thickness of approx lmm and
an inner wall of high density polyethylene (HDPE)
resin material having a maximum thickness of approx
150~un and having a volume approx 30cm3. Then, the ink
is sucked out through the ink supply port of the
negative pressure producing material chamber. It has
been confirmed that ink is consumed with the negative
pressure property similar to the those shown in Figure
6. The negative static pressure during the ink
stabilized supply period (H in Figure 6) was approx -
110mmAq.. The change of the negative static pressure
relative to the amount of the ink discharge was as
shown in Figure 7. Hy changing the material,
thickness of the inner wall of the ink accommodating
portion and/or the capillary force generated by the
negative pressure producing member, the following has
been found.
Figure 7 shows details of an actual example
of the negative pressure curve of Figure 6, and (1),
(2), (3) in the Figure corresponds to the (1), (2),
(3) in the foregoing disclosure of the operations.
CA 02396784 2002-09-05
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Figure 8 shows a detail of an example of A region in
Figure 7; Figure 9 illustrates the operation of the
ink container in the A region in Figure 7 in the order
of (a)-(c); Figure 10 shows an example of H region in
Figure 7; Figure 11 shows the operation of the ink
container in the B region in Figure 7 in the order of
(a)-(c). In Figures 9 and 11, suffix 1 indicates a
sectional view along the same line as with Figure 1,
(b), and suffix 2 indicates a sectional view taken
along a line A-A of the liquid containing chamber in
Figure 1, (b). For better understanding, the
deformation or the like of the ink accommodating
chamber is more or less exaggerated.
(1) region (1) in (1)
This region (before air-liquid exchanging
operation) is disclosed in the following three
patterns. The patterns are within the present
invention, and are dependent on the capillary force of
the negative pressure producing member, the thickness,
material or the like of the ink accommodating chamber
portion and the balance.
(First pattern in region (1) in Figure 7)
This pattern occurs generally when the ink
accommodating chamber rather than the negative
pressure producing member is ruling in the negative
pressure control. More particularly, when the
thickness of the ink accommodating chamber portion is
CA 02396784 2002-09-05
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relatively thick, or when the rigidity of the inner
wall of the ink accommodating chamber portion is
relatively high, this pattern tends to occur.
In the ink discharge from the initial state,
the ink is discharged from the negative pressure
producing member. This is because the resisting force
against the discharge of the ink from the negative
pressure producing member is smaller than the
resisting force against the discharge of the ink from
the ink accommodating chamber. After the ink is first
discharged from the negative pressure producing
member, the ink is discharged from the respective
chambers while balance is maintained therebetween.
When the ink is discharged from the ink accommodating
chamber, the inner wall is deformed inwardly.
(Second pattern in region (1) in Figure 7)
This pattern tends to occur when the negative
pressure producing member rather than the ink
accommodating chamber is ruling in the negative
pressure control, contrary to the case of the first
pattern. More particularly, this case tends to occur
when the inner wall of the ink accommodating chamber
is relatively thin, or when the rigidity of the inner
wall is small.
In the discharge of the ink in the initial
state, the ink is first discharged from the ink
accommodating chamber. This is because the resisting
CA 02396784 2002-09-05
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force against the discharge of the ink from the ink
accommodating chamber is smaller than the resisting
force against the discharge of the ink from the
negative pressure producing member. Thereafter, the
ink is discharged from the negative pressure producing
member and the ink accommodating chamber while balance
is maintained therebetween.
(Third pattern in region (1) in Figure 7)
In this pattern tends to occur when the
negative pressure producing member and the ink
accommodating chamber portion are similarly ruling
with respect to the negative pressure control. In
this case, in the ink discharge in the initial state,
the ink is discharged from the negative pressure
producing member and the ink accommodating chamber
while balance is maintained therebetween. With the
balance maintained, the air-liquid exchange state
which will be described hereinafter starts.
(2) region (2) in Figure 7
The description will be made as to air-liquid
exchanging operation region. This region is divided
into two patterns. For the purpose of detailed
description, the negative pressure curve in the region
(2) in Figure 7 is enlarged.
(First pattern of region (2) in Figure 7)
This pattern occurs generally when the ink
accommodating chamber rather than the negative
CA 02396784 2002-09-05
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pressure producing member is ruling in the negative
pressuxe control. More particularly, when the
thickness of the ink accommodating chamber portion is
relatively thick, or when the rigidity of the inner
wall of the ink accommodating chamber portion is
relatively high, this pattern tends to occur.
In the air-liquid exchanging operation
region, the ambience is introduced from the negative
pressure producing material chamber into the ink
accommodating chamber (Figure 8a region) This is to
balance the negative pressures. By the introduction
of the ink into the ink accommodating chamber, the
inner wall of the ink accommodating chamber slightly
deforms outwardly, as shown in Figure 9a. By the
introduction of the air, the ink is supplied into the
negative pressure producing material chamber from the
ink accommodating chamber, so that liquid level in the
negative pressure producing material chamber slightly
rises. (Figure 9a->b)
Hy the further discharge of the ink from the
head, the ink is first discharged from the negative
pressure producing member in this example. By this,
the liquid level in the negative pressure producing
material chamber lowers as shown in the Figure.
(Figure 8b region) ((Figure 9b)
after this state, the ink becomes discharged
from both of the negative pressure producing member
CA 02396784 2002-09-05
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and the ink accommodating chamber while the balance is
maintained therebetween. By this, the liquid level in
the negative pressure producing member lowers further,
and the inner wall of the ink accommodating chamber
deforms inwardly (Figure 8 region c) (Figure 9C).
After continuance of this state, the ambience
is introduced into the ink accommodating chamber
through the ambience introduction path, and Figure 7
region occurs.
(Second pattern in region (2) Figure 7)
This pattern tends to occur when the negative
pressure producing member rather than the ink
accommodating chamber is ruling in the negative
pressure control, contrary to the case of the first
pattern. More particularly, this case tends to occur
when the inner wall of the ink accommodating chamber
is relatively thin, or when the rigidity of the inner
wall is small.
As described in hereinbefore, the ambience is
introduced into the ink accommodating chamber from the
negative pressure producing material chamber in the
air-liquid exchanging operation region (region a in
Figure 10). By the introduction of the ink into the
ink accommodating chamber, the inner wall of the ink
accommodating chamber slightly deforms outwardly, as
shown in Figure 11a. By the introduction of the air,
the ink is supplied into the negative pressure
CA 02396784 2002-09-05
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producing material chamber from the ink accommodating
chamber, so that liquid level in the negative pressure
producing material chamber slightly rises. (Figure
l0a->b)
By the further ink discharge from the head,
the ink is mainly discharged from the ink
accommodating chamber in this pattern. In this case,
the negative pressure does not change greatly and
therefore gradually increases because of the thickness
and the rigidity of the ink accommodating chamber.
By the discharge of the ink, the inner wall of the ink
accommodating chamber gradually deforms inwardly
(region b in Figure 10). In this region, the ink is
hardly discharged from the negative pressure producing
member, and therefore, the liquid level of the
negative pressure producing member hardly changes.
In region b, when the ink is further
discharged, the ink is discharged from both of the
negative pressure producing member and the ink
accommodating chamber while the balance is maintained
therebetween (region c of Figure 10). In this region,
as described in the foregoing, the liquid level of the
negative pressure producing member lowers, and the
inner wall of the ink accommodating chamber deforms
inwardly (region c of Figure 10) (Figure 11c). After
this state continues, the ambience is introduced into
the ink accommodating chamber through the ambience
CA 02396784 2002-09-05
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introduction path, so that state of Figure 10a occurs.
(3) region (3) in Figure 7
Finally, region (3) in Figure 7 after the
air-liquid exchange region will be described. After
the air-liquid exchange ends, that is, most of the ink
in the ink accommodating chamber is discharged, the
ink is discharged only from the negative pressure
producing member. This region is divided into the
following two patterns.
(First pattern of region (3) in Figure 7)
In this example, the description will be made
as to the case where the pressure in the ink
accommodating chamber becomes substantially the
ambient pressure after the air-liquid exchange region.
After the end of the air-liquid exchange, the
ink in the ink accommodating chamber is hardly
discharged. In the state after the end of the air-
liquid exchange, a meniscus is generally formed in the
air vent path, the fluid communication path between
the negative pressure producing material chamber and
the ink accommodating chamber or in the negative
pressure producing member. However, when the liquid
level in the negative pressure producing member lowers
beyond the top end portion of the ambience
introduction path, the meniscus is broken by the
carriage vibration or the like. By this, the ink
accommodating chamber is brought into a fluid
CA 02396784 2002-09-05
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communication with the ambience through the air vent
path. Thus, the pressure in the ink accommodating
chamber becomes substantially ambient pressure. Then,
the inner wall of the ink accommodating chamber having
been deformed inwardly tends to restore by the
elasticity of itself. However, generally, it does not
return completely to the initial state. This is
because, yielding occurs when the inner wall deforms
inwardly beyond a certain degree by the discharge of
the ink from the ink accommodating chamber, in may
cases. Then, the ink accommodating chamber does not
completely restore even if the pressure therein
becomes ambient pressure.
Thus, after the pressure of the ink
accommodating chamber becomes the atmospheric
pressure, and the inner wall restores, the liquid
level in the negative pressure producing member lowers
by the discharge of the ink in the negative pressure
producing member. Thus, the negative pressure
increases substantially proportionally.
(Second pattern in region (3) in Figure 7)
In this pattern, even if the liquid level in
the negative pressure producing member lowers beyond
the top end portion of the ambience introduction path,
the ink accommodating chamber maintains the negative
pressure state. As described hereinbefore, the inside
of the ink accommodating chamber is isolated from the
CA 02396784 2002-09-05
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ambience by the meniscus in the ambience introduction
path, the fluid communication path and/or the negative
pressure producing member. With this state
maintained, the ink is consumed, and the liquid level
in the negative pressure producing member continues to
lower, as the case may be. Hy this, the ink is
consumed from the negative pressure producing member,
while the inner wall of the ink accommodating chamber
is kept deformed inwardly.
However, the meniscus may be broken by the
carriage vibration, ambient condition change or
another cause during the ink consumption, by which the
pressure in the ink accommodating chamber becomes
atmospheric. If this occurs, the inner wall of the
ink accommodating chamber restores substantially the
initial configuration. As described in the foregoing,
in the air-liquid exchanging operation in the
structure of this invention, the pressure variation
(amplitude Y and period) during the air-liquid
exchange is relatively larger than a conventional ink
container system using air-liquid exchange.
The reason for this is that inner wall of the
ink accommodating chamber is deformed inwardly by the
ink discharge before the air-liquid exchange, as
described with region (1) of Figure 7. Therefore, the
inner wall of the ink accommodating chamber is always
biased toward outside by the elastic force.
CA 02396784 2002-09-05
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Therefore, during the air-liquid exchange, the amount
of the air introduced into the ink accommodating
chamber may be larger in many cases than a
predetermined level in order to ease the pressure
difference between the negative pressure producing
member and the ink accommodating chamber portion. Hy
this, the amount of the ink discharged into the
negative pressure producing material chamber from the
ink accommodating chamber tends to be larger. In the
conventional system wherein the ink reservoir (ink
accommodating chamber) does not deform, the ink is
discharged into the negative pressure producing
material chamber immediately upon introduction of a
predetermined amount of the air.
In a solid image mode printing operation, for
example, a large amount of the ink is ejected. In
response, the ink is abruptly discharged from the
container. Even if this occurs, according to the
present invention, the ink supply does not stop
because of the above-described larger amount of ink
discharge in the air-liquid exchange. In the present
invention, the ink is discharged while the ink
accommodating chamber is deformed inwardly, a
buffering effect is significant against external
factors such as vibration thereof due to the carriage
movement or ambient condition change.
Referring to Figure 7, (b), further
CA 02396784 2002-09-05
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description will be made as to the operation during
the ink consumption, from another standpoint.
In the example of Figure 7, (b), the abscissa
represents time, and the ordinate represents an amount
of ink discharge from the ink accommodating portion
and an amount of air introduced into the ink
accommodating portion. The amount of ink supply to
the ink jet head is constant, here.
The solid line (1) is the amount of the ink
discharge from the ink accommodating portion, and the
ink accommodating portion is the amount of air
introduction into the ink accommodating portion.
From t=0 to t=tl, the air-liquid exchange is
not yet started (Figure 7, (a)). In this region, the
ink is discharged from the head from the negative
pressure producing member and the ink accommodating
portion, while the pressure balance is maintained
between them. The discharge patterns are as described
above.
The duration from t=tl to t=t2 corresponds to
the air-liquid exchange region (B region) of Figure 7,
(a). In this region, the air-liquid exchange occurs
on the basis of the negative pressure balance as
described above. As indicated by the solid line (1)
in Figure 7, (b), the ink is discharged from the ink
accommodating portion in accordance with the
introduction of the air into the ink accommodating
CA 02396784 2002-09-05
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portion (stepped portion of the solid line (2)). At
this time, the fact is not that amount of the ink
which is equal to the amount of the air introduced
into the ink accommodating portion, is immediately
discharged from the ink accommodating portion. Hut, a
predetermined period after the introduction of the
air, the amount of the ink which is equal to the final
total amount of the air is discharged. As will be
understood from the Figure, there is timing deviation
as contrasted to the operation of the conventional ink
container in which the ink accommodating portion does
not deform. The operation is repeated in the air-
liquid exchange region. At a certain point of time,
the amount of the air in the ink accommodating portion
and the amount of the ink therein is reversed. After
t=t2, the action enters the region (c region), that
is, the region after the air-liquid exchange, as shown
in Figure 7, (a). In this region, the pressure in the
ink accommodating portion becomes substantially equal
to the ambient pressure. (however, the ambient
pressure state is not reached depending ton the
situation, as described in the foregoing) the inner
wall of the ink accommodating portion restores the
initial position by the elastic force. Hut, by the
so-called yielding, it does not restore to the
completely initial state. Therefore, the final air
introduction amount Vc into the ink accommodating
CA 02396784 2002-09-05
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portion is smaller than the initial volume (V>Vc). In
the region, the ink in the ink accommodating portion
is used up. Referring to Figure 12, the description
will be made as to the case wherein the ink
accommodating chamber portion is exchanged in each of
the regions of the ink consumption.
(a) Exchange of ink container before air-liquid
exchange (Figure 12a)
Before the start of the air-liquid exchange,
the pressures are balanced between the negative
pressure producing member and the ink accommodating
chamber, while the ink is consumed. In this state,
the negative pressure itself is increasing
substantially in proportion to the consumption. The
ink level in the negative pressure producing member is
above the top end of the ambience introduction path.
When the ink accommodating chamber is exchanged in
this state, the negative pressure in the ink
accommodating chamber is low in the initial stage,
even to the extent that pressure is positive in some
cases. Therefore, if a fresh ink accommodating chamber
is mounted, the ink is supplied from the ink
accommodating chamber into the negative pressure
producing member with the result that liquid level in
the negative pressure producing material chamber
rises, and the rising stops when the balance is
reached therebetween. In this case, the upper portion
CA 02396784 2002-09-05
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of the negative pressure producing member functions as
a buffer region, so that even if the liquid level
rises, the ink does not leak through the air vent. Hy
the mounting of the ink accommodating chamber, the
negative pressure decreases even to the extent to
positive, as the case may be, but the proper negative
pressure is provided by initial recovery after the
container mounting. Thereafter, the ink is consumed
with the consumption pattern described in the
forgoing.
With the liquid supply system of the present
invention, even if the negative pressure producing
member is not filled with the ink adjacent the air-
liquid exchange path of the negative pressure
producing material chamber, the ink in the ink
accommodating portion can be moved into the negative
pressure producing member, if an ink path is formed
from the ink accommodating portion to the negative
pressure producing material chamber, by the capillary
force of the negative pressure producing material
chamber. Therefore, the ink in the ink accommodating
chamber can be assuredly used when it is mounted,
irrespective of the retaining state of the ink in the
negative pressure producing member adjacent the
connecting portion.
(b) Exchange of ink container during air-liquid
exchange(Figure 12b)
CA 02396784 2002-09-05
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in the air-liquid exchanging operation, the
liquid level of the negative pressure producing member
is generally stably at the tap end portion of the
ambience introduction path, and the inner wall of the
ink accommodating chamber is kept deformed.
When the ink accommodating chamber is
demounted in this state, and a fresh ink accommodating
chamber is mounted, the ink is supplied from the ink
accommodating chamber into the negative pressure
producing member with the result that liquid level in
the negative pressure producing member rises. More
particularly, the liquid level rises beyond the
ambience introduction path. Hy this, the inner wall
of the ink accommodating chamber displaces inwardly,
and the container is brought into a slightly negative
pressure state.
When the ink is consumed after the liquid
level is stabilized, the ink is consumed in accordance
with the consumption pattern ((1) -1- (1) -3). When
the predetermined negative pressure is reached the
air-liquid exchange occurs.
(c) Exchange of ink container after air-liquid
exchange (Figure 12c)
after the end of the air-liquid exchange, the
liquid level of the negative pressure producing member
is lower than the top end of the ambience introduction
path, and the pressure in the ink accommodating
CA 02396784 2002-09-05
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chamber is atmospheric with the inner wall takes
substantially the initial position, or the pressure
therein is negative with the inner wall being kept
deformed. When the ink accommodating chamber is
exchanged with this state, the ink in the ink
accommodating chamber is supplied into the negative
pressure producing member, and the liquid level in the
negative pressure producing member rises. Generally,
it rises beyond the top end of the ambience
introduction path, but balance may be reached when the
liquid level is below the top end. Hy the ink
discharge, the inner wall of the ink accommodating
chamber deforms inwardly, and the pressure therein
becomes substantially negative.
When the liquid level rises beyond the
ambience introduction path, the operation enters the
air-liquid exchanging operation region after the
above-described consumption process. When balance is
reached while the liquid level is below the top end of
the ambience introduction path, the air-liquid
exchanging operation starts immediately.
As described in the foregoing, the stable
negative pressure can be provided even when the ink
accommodating chamber is exchanged in any of the
consumption process (a)-(c), so that assured ink
supply operation is possible.
According to the ink container of the present
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invention, a small negative pressure variation can be
accommodated by the ink accommodating portion, and in
addition, even if the ink accommodating portion
contains the air as in the second ink supply state, it
can accommodate the change of the ambience differently
from the conventional method. Referring to Figures
13 and 14, the description will be made as to a
mechanism of stabilized liquid retaining when the
ambient condition is changed with respect to the ink
container of Figure 1. Figure 13 illustrates a
function, as a buffering absorbing material, of a
portion of the negative pressure producing member
which is above the air introducing groove, and a
buffer function of the ink accommodating portion, and
shows changes of the ink container from the state
(air-liquid exchange state) shown in Figure 4, (al),
(a2) when the air in the ink accommodating chamber is
expanded due to the rise of the ambient temperature or
the reduction of the atmospheric pressure. In this
Figure, suffix 1 indicates that it is a sectional view
taken along the similar plane as in Figure 1, (b); and
suffix 2 indicates that it is a sectional view taken
along a line A-A of the liquid containing chamber
shown in Figure 1, (b). Upon pressure reduction of
the ambient pressure (or rising of the ambient
temperature), the air in the ink accommodating chamber
expands. As shown in Figure 13(b1), (b2), the wall
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surface(1) constituting the ink accommodating portion
and the liquid level(2) are pressed so that inside
volume of the ink accommodating portion increases, and
a part of the ink discharges into the negative
pressure producing material chamber from the ink
accommodating portion through the air-liquid exchange
passage. Since the inside volume of the ink
accommodating portion increases, the amount of the ink
flowing into the negative pressure producing member
(which results in the rise of the liquid level in the
negative pressure producing member shown by (3) in
Figure 13(c1)) is significantly smaller than when the
ink accommodating portion is non-deformable. When
the pressure change is abrupt, the amount of the ink
flowing out through the air-liquid exchange passage
eases the negative pressure i the ink accommodating
portion, and increases the inside volume of the ink
accommodating portion, and therefore, at the initial
stage of the change, the resisting force of the wall
surface provided by easing the inward deformation of
the ink accommodating portion and the resisting force
against the injection into the negative pressure
generating member, are ruling.
The flow resistance against this injection is
larger than the resistance against the restoration of
the ink accommodating portion, so that when the air
expands, the inside volume of the ink accommodating
CA 02396784 2002-09-05
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portion increases, as shown in Figure 13(a1), (a2).
When the increase of the volume due to the expansion
of the air is larger than the upper limit of this
increase, the ink flows out into the negative pressure
producing material chamber from the ink accommodating
portion through the ait-liquid exchange passage, as
shown in Figure 13(b1), (b2). Thus, the walls of the
ink accommodating portion function as a buffer against
ambient condition changes, so that movement of the ink
in the negative pressure producing member is slow, and
therefore, the negative pressure property at the ink
supply port is stabilised.
In this embodiment, the ink discharged into
the negative pressure producing material chamber is
retained by the negative pressure producing member.
In this case, as shown in Figure 13(c1), (c2), the
amount of the ink in the negative pressure producing
material chamber temporarily increases with the result
of rising of the air-liquid interface, and therefore,
similarly to the initial stage of the use, the ink
pressure becomes temporarily slightly positive as
compared with the pressure in the stable period, but
the influence to the ejection property of the liquid
ejection recording means such as a recording head is
practically small enough. When the ambient pressure
returns to the level before the pressure reduction
(latm.) or when the temperature returns to the initial
CA 02396784 2002-09-05
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temperature), the ink discharged from the ink
accommodating.portion and retained in the negative
pressure producing member due to the ambience change
returns to the ink accommodating portion, and the
volume of the ink accommodating portion returns, too.
Referring to Figure 14, s (a) and (b), the
description will be made as to operation when the
stable state shown in Figure 13, (dl), (d2) is reached
under the changed pressure after the initial operation
after the pressure change.
This case is characterized by the change of
the interface of the ink retained in the negative
pressure producing member so that balance is
maintained against the changes of not only the amount
of the imk discharged from the ink accommodating
portion but also the negative pressure due to the
volume change of the ink accommodation per se As
regards the relation between the amount of the ink
absorption of the negative pressure producing member
and the ink accommodating chamber in the present
invention, from the standpoint of prevention of the
ink leakage through the air vent upon the pressure
reduction and temperature change, the maximum ink
absorption amount of the negative pressure producing
material chamber is determined in consideration of the
ink discharge amount from the ink accommodating
chamber under the worst condition and the amount of
CA 02396784 2002-09-05
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the ink to be retained in the negative pressure
producing material chamber during the ink supply from
the ink accommodating chamber, and the thus determined
volume of the negative pressure producing member is
contained in the negative pressure producing material
chamber.
Figure 14, (a) shows a volume of the initial
space (volume of the air) of the ink accommodating
chamber when the ink accommodating portion does not
deform at all against the expansion of the air
(abscissa (X)) vs the amount of the ink discharge when
the pressure is reduced to Patm. (0<P<1) (ordinate
(Y)) (broken line (1)).
As will be understood from the graph, the
amount of the ink discharge &V is approximately
expressed as follows, where P is the pressure upon the
pressure reduction ((0<P<1), a is a ratio of the
initial air amount in the ink accommodating chamber
((0<a<1), and VB is a volume of the ink accommodating
portion.
(1) When 0<_a<P
The amount of the air in the ink
accommodating chamber expanded by the pressure
reduction, is large when the amount of the remainder
is small, so that large amount of the ink is
discharged, and therefore, the amount of the ink
discharge 6V is proportional to the amount of the
CA 02396784 2002-09-05
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initial air:
8V = ((1-p)/p) x a x VB....(1)
(2) When P<a<_1
The amount of discharge cannot be larger than
the amount of the ink in the ink accommodating
chamber, it depends on the amount of the ink
accommodated initially:
8V= (1-a) x VH....(2)
Therefore, the estimation of the ink
discharge amount from the ink accommodating chamber
under the worst condition is such that when the
maximum pressure reduction condition of the ambient
pressure is 0.7atm., the maximum amount of the ink
discharging from the ink accommodating chamber occurs
when the vol;une VB of the ink in the ink accommodating
chamber remains in the ink accommodating chamber. If
the ink below the bottom end of the ink chamber wall
is also absorbed by the compressed absorbing material
in the negative pressure producing material chamber,
then all the ink (30~ of VB) remaining in the bottom
end portion m is considered as leaking out. In the
present invention, however, the ink accommodating
portion deforms in response to the expansion of the
air, so that inside volume of the ink accommodating
portion after the expansion is larger than the inside
volume of the ink accommodating portion before the
expansion, and the ink retaining level in the negative
CA 02396784 2002-09-05
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pressure producing material chamber changes so as to
maintain the balance against the variation of the
negative pressure due to the deformation of the ink
accommodating portion. In the stable state, the
negative pressure balance with the negative pressure
producing member in which the negative pressure is
reduced is kept by the ink from the ink accommodating
portion (the negative pressure in the ink supply port
in the negative pressure producing material chamber is
Q). When the reduced pressure is P (0<P<1); a ratio
of the amount of the initial air in the ink
accommodating chamber shown in Figure 13(a1), (a2) is
a (OSaSl); a volume of the ink accommodating portion
before the expansion, shown in Figure 13(a1), (a2) is
VB; a volume of the ink accommodating portion at the
initial state (or the state in which the outer surface
of the inner wall is closely contacted to the inner
surface of the outer wall) is V; the volume of the ink
accommodating portion in the stable state is VQ
(r=V/VH (r>1), r' =VQ/VB (1<r'~r), then the amount 8V
of the ink discharge is approximately:
(3) When O~a<Px r'
In this case, the ink accommodating portion
expands and discharge the ink. Since the ink
discharge amount dV from the ink accommodating portion
is a difference between the amount of the volume
change of the air in the ink accommodating portion and
CA 02396784 2002-09-05
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the amount of expansion of the ink accommodating
portion under the balanced state,
8V = ((1-p)/p) x a x VB
- (r'-1) x VB....(3)
Thus, the ink discharge amount is smaller by
the amount of expansion in the ink accommodating
portion. The amount of expansion of the ink
accommodating portion (r' -1) VH has a relation with
the negative pressure generated by the negative
pressure producing member, and the negative pressure
of the negative pressure producing member has a
relation with the amount of ink discharge of the ink
accommodating portion. An example of the relations
will be described. The amounts of the ink in the ink
accommodating portion before the pressure variation
and in the stable state will be considered. In Figure
13(d1), (d2), it is assumed that negative pressure
producing member is a capillary force generating
member having uniform capillary force generation
elements (no local unevenness) each of which is in the
form of tubes having a bottom surface area S, and that
liquid level in the stable state shown in Figure
13(d1), (d2) rises by 8h from the state before the
ambient condition change shown in Figure 13(a1), (a2).
SV=S x 6h....(4)
At this time, the negative pressure generated
at the ink supply port of the negative pressure
CA 02396784 2002-09-05
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producing member is changed by SQ from that before the
pressure variation toward the positive pressure
direction.
8Q= 8h....(5)
On the other hand, the difference between the
negative pressures in the ink accommodating portion
between before the pressure variation and in the
stable state is equal to 8Q since the negative
pressure balance is kept with the negative pressure
producing member. The relation between the
difference in the negative pressure and the amount of
volume variation is dependent on the configuration of
the ink accommodating portion, but they are generally
proportional, before the opposite maximum area sides
are contacted together. The proportional constant is
k (k>0).
8Q = k x ( VQ - VH )
- k x (r'-1) x VH ....(6)
From equations 4 to 6
6V = S x k x (r'-1) x VB ....(7)
From equations 3 to 7
6V =((S x k)/(1+Sxk)) x ((1-p)/p) x a x VB
- (1/(1+b)) x ((1-p)/p) x a x VB ......(8)
When the opposite maximum area sides of the
ink accommodating portion are contacted to each other
before the pressure variation, the relation between
the volume of the ink accommodating portion and the
CA 02396784 2002-09-05
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generated negative pressure is different depending on
whether they are contacted or not. Therefore, the
relation between the initial space volume of the ink
accommodating chamber before the pressure reduction
and the ink discharging amount is not linear as
represented by equation 8, but has an inflection
point. When the cross-sectional areas of the
negative pressure producing members are different
depending on the heights, or when the densities of the
capillary force generation elements are not uniform,
the respective factors are taken into account. In
equation 3, when V<0, then V=0. In other words, the
movement of the ink does not occur through the air-
liquid exchange passage (communicating portion) in
this state, and only the expansion of the inside
volume of the ink accommodating portion occurs.
(4) When P x r' SaSl
The amount of discharge cannot be larger than
the amount of the ink in the ink accommodating
chamber, it depends on the amount of the ink
accommodated initially:
8V = (1-a) x VB ..... (9)
Figure 14, (a) shows a volume of the initial
space of the ink accommodating chamber (volume of the
air) before the pressure reduction abscissa (X) vs an
ink discharge amount in the stable state when the
pressure is reduced to Patm. (0<P<1) ordinate (Y)
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(solid line (2)). Under the above-described
condition, the ink discharge amount has an inclination
which is less steep by 1/ (1+b) (0<b = 1/(S x k)), as
shown by the solid line in Figure 14, (a).
As will be understood from the broken line
(1) and the solid line (2) in Figure 14, (a), the
estimation of the ink discharging amount from the ink
accommodating chamber under the worst condition, can
be made smaller then when the ink accommodating
portion does not deform at all in response to the
expansion of the air. This phenomenon applies upon
the temperature change of the ink container, and
therefore, the discharging amount is smaller during
the pressure reduction even if the temperature rises
approx 50 deg.
As described in the foregoing, according to
the ink container of the present invention, the
expansion of the air in the ink accommodating chamber
due to the change of the ambience condition, can be
accommodated not only by the negative pressure
producing material chamber but also by the ink
accommodating chamber having the buffer effect
provided by the increase of the volume of the ink
accommodating chamber per se until the outer periphery
of the ink accommodating portion becomes substantially
equal to the inner periphery of the casing. Thus, the
ink accommodation capacity of the ink accommodating
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chamber can be significantly increased while accepting
the ambient condition change.
Figure 14, (b) schematically shows the volume
of the ink accommodating portion and the ink discharge
amount from the ink accommodating portion, with time,
when the ambience of the container is changed from the
atmospheric pressure (t=0) to Patm. (0<P<1) (pressure-
reduced state) wherein the volume of the air at the
initial stage is VA1, In Figure 14, (b), the
abscissa represents time (t), and the ordinate is a
volume of the ink accommodating portion and the amount
of the ink discharge from the ink accommodating
portion, wherein change, with time, of the amount of
the ink discharge from the ink accommodating portion
is indicated by, and the solid line (1), and the
change, with time, of the volume of the ink
accommodating portion is indicated by the solid line
(2). In Figure 14, (b), the states of the ink
container corresponding to t=ta, t=tb, t=tc, t=td are
shown in Figure 13 (a), (b), (c), (d), respectively.
As shown in Figure 14, (b), upon abrupt
ambience change, the ink accommodating chamber can
accommodate the expansion of the air, before the
stable state wherein the negative pressures are
balanced between the negative pressure producing
material chamber and the ink accommodating chamber, is
finally reached. Therefore, the ink discharge timing
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(from the ink accommodating chamber to the negative
pressure producing material chamber) can be delayed
upon an abrupt ambient condition change.
Therefore, according to the ink supplying
system of the present invention, even under the
various use condition, the tolerance for the air
expansion of the air introduced by the air-liquid
exchange is enhanced, and the ink supply is
accomplished with stabilization negative pressure
during the use of the ink accommodating chamber.
According to the ink supplying system of the present
invention, the volume ratio between the negative
pressure producing material chamber and the ink
accommodating chamber can be determined relatively
freely by properly selecting the material of the ink
accommodating portion and the negative pressure
producing member, even to the extent of 1:2 or larger
with practicality. When the buffer effect of the ink
accommodating chamber is important, the deformation of
the ink accommodating portion in the air-liquid
exchange state from the state at start of use is
increased within the range of the elastic deformation.
For the purpose of effective buffer effect of
the ink accommodating portion, it is desirable that
amount of the air in the ink accommodating portion
when the deformation of the ink accommodating portion
is small, namely, that amount of the air in the ink
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accommodating portion of the function in the ink
accommodating portion before the air-liquid exchange
state after the connection, is small.
In the foregoing, first embodiment has been
described. Another embodiment will be described. In
the following embodiments and in the foregoing
embodiment, various elements can be combined.
(Second embodiment)
Figure 15 is a schematic illustration of an
ink container according to a second embodiment to
which the liquid supply system of the present
invention is applicable, wherein (a) is a perspective
view, (b) is a sectional view. In this embodiment, a
communication tube(air-liquid exchange passage) 114 is
projected upwardly in the vertical direction from a
side opposed to the bottom surface of the negative
pressure producing material chamber 110, and a liquid
plenum 118 is provided at a negative pressure
producing material chamber side end of the
communication tube in place of contact with the
negative pressure producing member, and the casing of
the negative pressure producing material chamber 110
is provided with a guiding member 111A for guiding the
ink accommodating chamber 150. These are different
from first embodiment. Lateral sides of the ink
accommodating chamber 150 are provided with respective
CA 02396784 2002-09-05
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projected portions 1508, and correspondingly, the
guiding member 111A is provided with recesses 1118.
In the other respects, the structure is similar to
that of the container according to Embodiment 1. A
negative pressure producing material chamber 110 holds
a negative pressure producing member 113 in a casing
111, and is provided with an ink supply port 112, an
air vent 115, a buffer portion 116 and an air
introducing groove 117. The ink accommodating chamber
150 has an ink accommodating portion 153 constituted
by the inner wall 154 having an outer surface
corresponding to the inner shape of the casing(outer
wall) 151. It has air vent 155, a pinch-off portion
156 and an ink discharging outlet 152 sealed by
sealing means 157 such as a film. The ink discharge
port 152 is provided with an O-ring 160 as a seal
member, and when the negative pressure producing
material chamber and the ink accommodating chamber are
connected to each other, the connecting portion is
seal thereby.
By the provision of the communication tube
extended from a side opposite to the bottom surface of
the negative pressure producing material chamber, the
ink accommodating chamber can be easily mounted to or
demounted from the negative pressure producing
material chamber in a direction perpendicular to the
bottom surface of the negative pressure producing
CA 02396784 2002-09-05
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material chamber. At this time, the positioning
between the ink discharge port of the ink
accommodating chamber and the communication tube of
the negative pressure producing material chamber can
be easily effected by a guiding member 111A.
Therefore, when the sealing means 157 is unsealed, the
communication tube is free of additional force, thus
permitting assured connection. The container is fixed
by engagement between a projected portion 150B
provided in the ink accommodating chamber and a recess
111B provided in the guiding member 111A, and the seal
of the connecting portion is assured together with the
O-ring. A cut-away portion 111C provided in the
guiding member is used when the ink accommodating
chamber is dismounted.
In this embodiment, the liquid plenum is not
inevitable by using L-shaped communication tube, for
example. As regards the liquid plenum, the volume is
preferably as small as possible, since then the amount
of the air moving into the ink accommodating chamber
upon the connection can be reduced. If it is
necessary to use a liquid plenum having a large size,
the liquid plenum may be provided with a liquid
detecting mechanism (for example, two electrodes are
disposed in the liquid plenum, and the resistance
value between the electrodes is measured). (third
embodiment)
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Figure 16, (a) is a schematic illustration of
an ink container according to a third embodiment,
usable with the liquid supply system according to the
present invention.
In this embodiment, an integral head
cartridge 300 is constituted by liquid ejection
portions 301 capable of ejecting different liquids
(yellow (Y), magenta (M) and cyan (C) inks in this
embodiment) and negative pressure producing material
chambers 410, 510, 610 accommodating the liquids,
wherein the ink accommodating chambers 450, 550, 650
are detachably mountable relative to the head
cartridge 300,
In this embodiment, in order to assure the
connection between the ink accommodating chambers and
the associated negative pressure producing material
chambers, the head cartridge 300 is provided with a
holder portion 302 which coverings a part of outer
surfaces of the ink accommodating chambers. The ink
accommodating chambers are provided with latch levers
459, 559, 659 having locking claws. A guiding member
is provided with engaging holes 303a, 303b, 303c
corresponding to the locking claws. Therefore, the
connecting state is maintained assuredly. The
respective liquid containers 450, 550, 650 have
substantially the same configurations, and by
provision of identification label (unshown) for
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preventing erroneous mounting, the correct mounting is
assured. The holder configurations may be different
depending on the colors to prevent the erroneous
mounting. In this case, the volumes may be made
different taking the use frequencies of the colors
into account. As a modified example of the
embodiment, the negative pressure producing material
chambers 410, 510, 610 may be made separable relative
to the liquid ejection portion, as shown in Figure 16,
(b). In this case, only one black (Bk) may be
provided on the ink accommodating chamber. Hy the
integral configuration as in this embodiment, the
erroneous mounting of the container can be prevented.
In this embodiment and the modified example
thereof, the liquids may be other than the Y, M and C
inks, and the number and combination of the
accommodated liquid containers (for example, only
black (Bk) container is a single container, and Y, M,
C containers constitute an integral container).
(other embodiments)
Other embodiments and modifications will be
described. The following embodiments are applicable
to each of the above-described embodiments.
(Structure of the ink accommodating chamber)
Additional description will be made as to the
structure of the ink accommodating chamber in each of
the embodiments described above.
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When the ink accommodating chamber is
detachably mountable relative to the negative pressure
producing member, a sealing means is provided at the
communicating portion between the ink accommodating
chamber and the negative pressure producing material
chamber to prevent leakage of the ink from the ink
accommodating portion before the connection and to
prevent leakage of the liquid and/or the air through
the communicating portion upon connection. In this
embodiment, the sealing means is in the form of a
film-like, but it may be ball-like. Alternatively,
the air-liquid exchange passage may be provided by a
hollow needle, and the sealing means is a rubber plug.
The ink accommodating chamber of each of the
above-described embodiments are manufactured by a
direct blow manufacturing method. The casing(outer
wall) and the ink accommodating portion(inner wall)
which are separable from each other, are provided by
uniformly expanding a cylindrical parison to a
substantially a prism-like mold by air blow. In an
alternative structure, a metal spring or the like may
be provided in a flexible bladder, so that negative
pressure is generated in accordance with ink
discharge.
However, by using blow molding, the ink
accommodating portion having an outer surface
configuration similar to or equivalent to the inner
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surface configuration of the casing can be easily
manufactured, and in addition, the negative pressure
level generated can be easily selected by changing the
material and the thickness of the inner wall
constituting the ink accommodating portion. By using
thermoplastic resin material for the outer wall, the
ink accommodating chamber can be recyclable. By using
the blow molding, the ink container shown in Figure 17
can be easily manufactured for the integral type
container as has been described with third embodiment.
Figure 17 is a perspective view of an example of an
ink accommodation container with plural ink
accommodating chambers, wherein (b) is a sectional
view taken along an A-A in Figure 17, (a). The ink
accommodation container 750 has a plurality of ink
accommodating portions 753a, 753b, 753c for retaining
the inks, and ink discharge ports 752a, 752b, 752c
sealed by the sealing means 757a, 757b, 757c can be
connected. In the ink accommodation container 750
shown in Figure 17, the sizes of the ink accommodating
portions are different. By the difference, the
accommodation capacities can be made different
depending on the use frequencies of the liquids. The
description will be made as to the structure of the
outer wall and the inner wall.
In each of the above-described embodiments,
the ink accommodating chamber is manufactured by the
CA 02396784 2002-09-05
blow molding, and therefore, the thickness is smaller
in the corner portions than in the central portions of
the sides. Similarly, the thickness of the outer wall
is smaller in the corner portions than in the central
portions of the sides.
As a result, the inner wall acquires the
outer shape which is the same as the inner shape of
the outer wall. The outer surface of the inner wall
extends along the thickness distribution of the outer
wall, and therefore, it is convex toward the ink
accommodating portion constituted by the inner wall.
The inner surface of the inner wall has the above-
described thickness distribution, and therefore, it is
further convex toward the ink accommodating portion.
These structures result in the above-described
function in the maximum area sides, and therefore, the
convex shape is desirable at least in the maximum area
sides, thedegree of convexity of the internal wall
surface may be not more than 2mm, and that of the
outer surface of the inner wall may be not more than
lmm. The convex shape may be within a measurement
error range in a small area sides. Thus, the convex
shapes determine the priority of deformation of the
sides.
The structure of the outer wall will be
described. The above-described outer wall has a
function of limiting the deformation of the inner wall
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at the corner portions. For this function, it can
maintain the configuration thereof against the
deformation of the inner wall, and it covers the
outside of the corner portions (corner portion
enclosing member). The outer wall or the inner wall
may be covered by plastic resin material, metal or
thick paper. The outer wall may cover the whole
surface, or only the corner portions have a surface
structures, which are connected each other with metal
rods or with a mesh structure.
If the ink is disconnected between the
neighborhood of the air-liquid exchange path of the
negative pressure producing member and the
neighborhood of the ink supply port for some reason or
another when the ink accommodating chamber is
exchanged in the case of the exchangeable ink
accommodating chamber, the ink in the ink
accommodating chamber can be forced into the negative
pressure producing material chamber by temporarily
presses the outer wall which is elastically deformable
manually, as shown in Figure 18, by which the ink can
be made continuous. The pressing refreshing process
may be effected automatically rather than manually.
Means for the pressing can be provided in the
recording device. When the structure is such that
part of the inner wall is exposed, the exposed portion
of the inner wall can be pressed.
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In this embodiment, the ink accommodating
portion has a prism-like shape, but the shape is not
limiting. It may be any, if it is deformable with the
ink discharge and is capable of generating the
negative pressure despite the deformation.
It is preferable that one-to-one relation
between the deformation of the ink accommodating
portion and the negative pressure at the ink discharge
port can be maintained, even if the deformation and
the restoration of the ink accommodating portion are
repeated. This can be accomplished by deforming the
ink accommodating portion within the elastic
deformation range.
In this embodiment, even if the pressure at
the ink discharge portion~becomes zero after the air-
liquid exchanging operation, the ink accommodating
portion is still kept deformed slightly. So, even if
the deformation of the ink accommodating portion is
not elastic in a part, it is usable if the other part
deforms elastically.
When the ratio of the change of the negative
pressure due to the deformation of the ink discharge
abruptly changes (for example, by the deformed
portions being abutted to each other), it is desirable
that above-described first ink supply state is
completed and the above-described second ink supply
state is started before the abrupt change, even if the
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elasticity still exist even after the change. The
material for the use in the liquid accommodating
container may be any if the inner wall and the outer
wall are separable, and each or one of the inner wall
and the outer wall may be of multi-layered structure
of a plurality of materials. A higher elasticity
material is usable for the inner wall than when the
ink accommodating chamber alone is used as an
accommodating container. Therefore, as compared with
the case when the ink accommodating chamber alone is
used as a negative pressure producing container, a
thicker inner wall or a more rigid material are usable
for the replenishing ink chamber for ink jet printing,
thus expanding the latitude of material selection.
Increase of the thickness of the inner wall is
effective to lower the gas permeability of the ink
accommodating chamber. The decrease of the gas
permeability is preferable since the expansion and/or
the ink leakage of the ink accommodating chamber can
be prevented when the ink accommodating chamber is
transported or kept unused. In consideration of the
influence to the ink accommodated inside, the
preferable material of the inner wall is for example
polyethylene resin material, polypropylene resin
material or the like. In the foregoing embodiments
and examples, the inner wall and the outer wall have a
single layer structure, but the inner wall and/or the
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outer wall may be of a multi-layer structure.
Particularly, in the present invention, as compared
with the case when the ink accommodating chamber alone
is used as a negative pressure producing container, a
thicker inner wall or a more rigid material are usable
for the replenishing ink chamber for ink jet printing,
thus expanding the latitude of material selection, the
number of combinations of the materials for the inner
wall is larger.
(Structure of the negative pressure producing material
chamber)
Additional description will be made as the
structure of the negative pressure producing material
chamber in each of the embodiments.
The negative pressure producing member
accommodated in the negative pressure producing
material chamber(accommodating container for the
negative pressure producing material) may be a porous
member or material such as polyurethane foam, felt-
like material of fibers, heat-molded mass of fibers or
the like. The air-liquid exchange
passage(communicating portion) has been described as
being tube like, but it may be any if the air-liquid
exchange is not obstructed in the air-liquid exchange
state.
In each of the embodiments, the air
introducing groove is formed on the inner surface of
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the casing, but it is not inevitable as shown in
Figure 19. Figure 19 is a sectional view of a
container according to the first embodiment, but the
air introducing groove may be omitted in the other
embodiments. In this embodiment, the liquid level is
generally maintained at a lower position during the
air-liquid exchanging operation. In this case, when a
large amount of the ink is discharged, in the above-
described solid mode printing, the liability of
occurrence of the ink discontinuance is higher than
when the air introducing groove is provided.
However, when the ink accommodating chamber is
deformable, the discharge amount of the ink during the
air-liquid exchange, is large so that liability of
occurrence of the ink discontinuance is lower. By
the provision of the air introducing groove for
promoting the air-liquid exchange, the air-liquid
interface can be easily formed, so that ink supply is
further stabilized. In other words, the liquid
supplying operation to the outside such as the
recording head is stabilized. The air-liquid
interface is further stabilized by taking into account
the connection between the negative pressure producing
member; and the ink accommodating portion under
various conditions such as the first supply state and
the second supply state.
In each of the foregoing examples, a space
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(buffer portion) not having the negative pressure
producing member is provided adjacent the top portion,
but this space may be replaced with the negative
pressure producing member not containing the liquid
under the normal conditions. By the provision of the
negative pressure producing member not retaining the
liquid in the buffer space, the ink moved to the
negative pressure producing material chamber due to
the ambient condition change can be retained.
(Ink container)
In each of the foregoing embodiments, the ink
accommodating chamber has beep described as being
detachably mountable relative to the negative pressure
producing material chamber, but as shown in Figure 20,
the two chambers may be always integral. In the case
that after the chambers are molded through different
molding methods (for example, injection molding for
the negative pressure producing material chamber, and
blow molding for the ink accommodating chamber), they
are welded or bonded (integral), the communicating
portion is desirably sealed by a sealing member such
as O-ring 58, similarly to the above-described
embodiments so as to prevent ink leakage from the
communicating portion where the two chambers are
connected.
The liquid supplying operation in the ink
container shown in Figure 20 at the start of the use,
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is alxeady at the stage after the completion of the
above-described state at start of use. The
advantageous effects of the foregoing embodiments can
be used in the other supply operation stages.
(Liquid supplying operation and ink supplying system)
An additional description will be made as to
the liquid supplying operation and the ink supplying
system. As regards the ink supply operation in the
ink container (ink supplying system) in each of the
foregoing embodiments, the operations proceed from the
initial state where the ink accommodating chamber and
the negative pressure producing material chamber are
not connected, the state at start of use (upon
connection therebetween), the first and second ink
supply states. They are one example of liquid
supplying operation in the ink supplying system of the
present invention, and the following operations, for
example, may occur depending on the structures of the
ink accommodating chamber and the negative pressure
producing material chamber and/or the liquid discharge
condition.
In a first modified example, with an ink
supplying system without the air-liquid exchange state
namely the second ink supply state, there is a process
of using the ink from the ink accommodating portion
without the introduction of the ambience into the ink
accommodating portion, and therefore, as regards the
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limit of the inside volume of the liquid accommodating
container, the air introduced into the ink
accommodating portion upon the connection has only to
be considered. Thus, even if the limit to the inside
volume of the ink accommodating chamber is eased, the
ambient condition change can be accommodated. This is
advantageous. However, when the usage efficiency of
the ink accommodating portion is considered, the ink
in the ink accommodating portion can be more easily
consumed when the air-liquid exchange state occurs
after the first ink supply state, as in each of the
foregoing embodiments.
As regards the second modified example, the
liquid level of the negative pressure producing
material chamber before the connection is higher than
the air-liquid interface as the case may be in the
state shown in Figure 2(a1), (a2). In this case,
among the motions of the ink toward the state at start
of use disclosed referring to Figure 2(b1), (b2), the
unidirectional ink movement due to the capillary force
into the negative pressure producing material chamber.
In a third modified example, the consumption
speed of the ink is extremely high in the state shown
in Figure 3(b1), (b2), for example. In this case, the
negative pressures of them are not always balanced,
but the ink in the negative pressure producing
material chamber is first consumed until the
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difference of the negative pressures of them, and when
the difference of the negative pressures becomes
larger than a predetermined level, the ink moves from
the ink accommodating chamber into the negative
pressure producing material chamber. Such modified
examples are within the sprit of the present invention
with the ink supply operation and the detail.
(Liquid ejection recording device)
The description will be made as to an ink jet
recording apparatus for effecting recording with the
ink container according to an embodiment of the
present invention, shown in Figure 1. Figure 21 is a
schematic view of an ink jet recording apparatus
carrying the ink container according to an embodiment
of the present invention. In Figure 21, a head unit
(unshown) and an ink container 100 are detachably
mounted on the main assembly of the ink jet recording
apparatus by positioning means (unshown) of a carriage
4520 and a connecting plate 5300 rotatable about an
axis. The forward and backward rotation of the
driving motor 5130 are transmitted to the lead screw
5040 through the drive transmission gears 5110, 5090
to rotate it. The carriage 4520 has a pin (unshown)
engaged with the spiral groove 5050 of the lead screw
5040. With this structure, the carriage 4520 is
reciprocated in a longitudinal direction of the
apparatus.
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Designated by 5020 is a cap for Gaping a
front side of each of the recording heads of the
recording head unit, and is used for suction recovery
for the recording head through an opening in the cap
by unshown suction means. The cap 5020 is moved by
driving force transmitted through the gear 5080 or the
like to cover the ink ejection outlets of each of the
recording heads. Adjacent the cap 5020, there is
provided a cleaning blade which is supported for
vertical movement. The blade is not limited to the
one disclosed, but any known cleaning blade is usable.
The capping, cleaning and suction recovery
are actuated by the lead screw 5050 when the carriage
4520 moves to the home position at the respective
positions. Any other means is usable for this purpose.
The description will be made as to advantages when the
ink container of the present invention is carried on
such a reciprocable carriage.
The ink accommodating chamber of the ink
container of the present invention is deformable, and
therefore, the motion of the ink caused by the
scanning of the carriage can be accommodated by the
deformation of the ink accommodating portion. In
order to prevent the negative pressure variation
against the scanning of the carriage, it is desirable
that a part of the corner portions of the ink
accommodating portion is not separated from the inner
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surface of the casing or that it is close thereto,
even if they are separated. In the case of an ink
accommodating portion having opposite maximum area
sides as in this embodiment, when the container is
carried on the carriage such that maximum area sides
are substantially perpendicular to the scanning moving
direction, the ink motion easing effect is
particularly significant.
As described in the section of (Structure of
ink accommodating chamber), the recording device may
be provided with pressing refreshing means 4510 for
pressing the inner wall through the outer wall of the
ink accommodating chamber. In this case, there may be
provided liquid presence or absence detecting means
5060 including light emitting means and receiving
means whereby light is passed through the ink
accommodating chamber and is received by the light
reflected to detect the presence or absence of the
ink, ejection failure detecting means(unshown) for
detecting ejection failure of the recording head and
control means(unshown), so that ink stop from the
neighborhood region of the air-liquid exchange path of
the negative pressure producing member to the
neighborhood region of the ink supply port using the
following sequence for example.
In the case that ink accommodating chamber is
exchanged, after the normal suction recovery process
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using the cap 5020, the ejection of the recording head
using the exchanged ink accommodating chamber is
checked. If the ejection failure is detected, pressing
refreshing operation is carried out using the pressing
refreshing means 4510 by which normal state is
restored. In the case that during the operation, the
liquid presence or absence detection detecting means
may detect the presence of the ink in an ink
container, whereas the ejection failure detecting
means detects the ejection failure in the recording
head using the container, the normal suction recovery
process is carried out. If the ejection failure
continues even after the normal suction recovery
process, the pressing refreshing operation using the
pressing refreshing means 4510 may be carried out. In
any case, the recording head corresponding to the ink
container subjected to the pressurizing recovery, is
covered by the cap, so that unintended ink leakage
through the recording head is prevented. The liquid
presence or absence detection detecting means is not
limited to the above-described optical, but may be a
dot count type or another type, or combination
thereof. As described in the foregoing, the liquid
containing portion deforms such that balance is kept
with the negative pressure of the negative pressure
producing member, and therefore, even if the air in
the liquid containing portion expands due to the
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ambient condition change, the liquid containing
portion restores to toward the initial size and volume
if the change is abrupt, thus minimizing the influence
of the ambience change. If the change in the ambience
is not abrupt, the influence of the expansion is
removed eventually both by the negative pressure
producing member and the liquid containing portion
while the balance is maintained with the negative
pressure producing member. Therefore, the required
size of the buffer space in the negative pressure
producing material chamber can be reduced under
various using conditions.
In the second liquid supply process, the air
is introduced into the liquid containing portion, so
that liquid in the liquid containing portion is used
up substantially without an unusably remaining amount
ink, and the negative pressure difference between at
the time of the start of the liquid discharge from the
liquid containing portion and at the time of the end
thereof, can be smaller than that when the liquid
containing portion alone is used as a negative
pressure producing container. As compared with the
conventional type ink container having the negative
pressure producing material chamber, the ink
accommodating chamber and the communication port
therebetween, the allowance to the air expansion is
larger. Even if a large amount of the ink is consumed
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in a short period of time, the liquid supply from the
liquid containing portion into the negative pressure
producing material chamber is smooth since the liquid
containing portion is deformable. Therefore, the ink
supply is stabilized when the ink in the liquid
containing portion is consumed. According to this
system, even if the accommodating container for the
negative pressure producing material does not contain
the liquid in the neighborhood of the communicating
portion to the liquid accommodating container, the
liquid can be moved from the liquid accommodating
container into the negative pressure producing member
using the capillary force in the negative pressure
producing material chamber upon the mounting of the
liquid accommodating container to the negative
pressure producing material chamber, so that liquid in
the exchanged liquid accommodating container can be
assuredly used by the simple mounting, irrespective of
the liquid retaining state of the negative pressure
producing member adjacent the connecting portion.
Thus, a practical liquid supply system with stabilized
liquid supply can be provided.
According to the present invention, the ink
can be used from the ink accommodating portion without
introducing the air into the ink accommodating
portion, an ink container and an ink supplying system
with high ink accommodation efficiency, usage
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efficiency and with high immunity against ambient
condition change can be provided. Therefore, the
size of the container can be downsized, and the
running cost can be reduced.
While the invention has been described with
reference to the structures disclosed herein, it is not
confined to the details set forth and this application
is intended to cover such modifications or changes as
may come within the purposes of the improvements or the
scope of the following claims.
20
