Note: Descriptions are shown in the official language in which they were submitted.
214~36
--1
S~U~ ~, PROCESS CARTRIDGE AND
IMAGE FORMING APPARATUS
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a process
cartridge, a shutter usable with the process cartridge
and an image forming apparatus usable with the process
cartridge.
Here, the image forming apparatus includes an
electrophotographic copying machine, an
electrophotographic printer (for example, LED printer,
laser beam printer), an electrophotographic facsimile
machine, an electrophotographic word processor, and
the like.
The process cartridge means a cartridge
having as a unit an electrophotographic photosensitive
member, and charging means, developing means and
cleaning means, which is detachably mountable to a
main assembly of an image forming apparatus. It may
include as a unit an electrophotographic
photosensitive member and at least one of charging
means, developing means and cleaning means. It may
include as a unit developing means and an
electrophotographic photosensitive member.
An image forming apparatus using
electrophotographic process is known which is used
with the process cartridge. This is advantageous in
22l4~936
that the maintenance operation can be, in effect,
carried out by the users thereof without expert
service persons, and therefore, the operativity can be
remarkably improved. Therefore, this type is now
widely used.
In such a process cartridge, the
photosensitive member, for example, may be
deteriorated when it is exposed to light, or it may be
damaged by physical contact with other part, or the
photosensitive member may be damaged. It order to
avoid them, provision of shutter member is known, for
example, U.S. Patent No.s 4,470,689 and 5,113,220.
The former discloses a process cartridge
having a shutter for protecting an image transfer
region of the photosensitive member, and the latter
discloses a drum cartridge having two-part shutter
member.
These are effective to protect the
photosensitive member.
This invention is intended to provide a
further improvement.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the
present invention to provide a shutter for protecting
an electrophotographic photosensitive member, a
process cartridge using the shutter, and a image
- 3 21~793~
forming apparatus usable with the process cartridge.
It is another object of the present invention
to provide a shutter having a opening and closing
mechanism which is simple in the structure, a process
cartridge using the shutter, and a image forming
apparatus usable with the process cartridge.
It is another object of the present invention
to provide a shutter constituted by a small number of
parts and easy to assemble, a process cartridge using
the shutter, and a image forming apparatus usable with
the process cartridge.
It is a further object of the present
invention to provide a shutter including a first
shutter member and a second shutter member, which are
integral, and a process cartridge using the shutter,
and a image forming apparatus usable with the process
cartridge.
It is a further object of the present
invention to provide a shutter to make a shutter
member openable and closable with a simple structure
wherein a longitudinal dimension is small, a process
cartridge using the shutter, and a image forming
apparatus usable with the process cartridge.
It is a further object of the present
invention to provide a shutter having a first shutter
member and a second shutter member interrelated so
that the mechanism is simplified, a process cartridge
21~793~
--4--
using the shutter, and a image forming apparatus
usable with the process cartridge.
These and other objects, features and
advantages of the present invention will become more
apparent 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 sectional view of an image
forming apparatus comprising a process cartridge.
Figure 2 is a sectional view of the process
cartridge.
Figure 3 is a perspective view of the process
cartridge.
Figure 4 is an explanatory drawing, which
depicts how the cover of the image forming apparatus
is opened and the process cartridge is installed in
the apparatus.
Figure 5 is a sectional view of a developing
means.
Figure 6 is a perspective view illustrating
separately the frame and wall members of the
developing means.
Figure 7 is a perspective view illustrating
how the developing means frame and the developing
- 5 21~7936
means wall are attached.
Figure 8 is a perspective view of a shutter
member.
Figure 9(a) is a plan view of the shutter
member, and Figure 9~b) is a side view of the shutter
member, as seen from the longitudinal direction.
Figure lO is a sectional view of the shutter
member, which is open.
Figure 11 is a perspective view of the
shutter member, which is open.
Figure 12 is a side view of the process
cartridge.
Figure 13 is a sectional view of a portion
that serves as a guide during the cartridge
installation.
Figure 14 is an explanatory drawing, which
depicts how the process cartridge is removed from the
image forming apparatus, wherein the first projection
is in engagement with a recessed portion.
Figure 15 is an explanatory drawing, which
depicts how the process cartridge is removed, wherein
the process cartridge has been rotated about the
second projection by pulling a knob.
Figure 16 is an explanatory drawing, which
depicts how the process cartridge is removed, wherein
the process cartridge is being pulled out by pulling
it by the knob.
21~7936
--6--
Figure 17 is a sectional view of a different
type of process cartridge, the knob of which is not
provided on the top.
Figure 18 is a sectional view of another
embodiment of developing means, which comprises a seal
retaining portion.
Figure l9 is a sectional view of another
- embodiment of developing means, in which the wall
member is provided with a hinge portion.
Figure 20 is a sectional view of another
embodiment of shutter, in which the first and second
shutter portions are interlocked with a link portion.
Figure 21 is a sectional side view of another
example of the process cartridge in accordance with
the present invention.
Figure 22(a) is a left side view of the
- cleaning means frame of the process cartridge
illustrated in Figure 21, and Figure 22(b) is a right
side view of the cleaning means frame of the same.
Figure 23 is an explanatory drawing, which
depicts how the process cartridge illustrated in
Figure 21 is installed into, or removed from, the main
assembly of the image forming apparatus.
Figure 24 is an explanatory drawing, which
depicts the moment that works when the process
cartridge illustrated in Figure 21 is installed into
the apparatus main assembly.
~ _7_ 21~93~
Figure 25 is an explanatory drawing, which
depicts the moment that works when the process
cartridge illustrated in Figure 21 is removed from the
apparatus main assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first embodiment will be described as a
preferable embodiment, referring to Figures 1 to 16,
and then, other embodiments will be described
referring to Figures 18 to 20, and Figures 21 to 25.
Embodiment 1
The first embodiment will be described
regarding: (1) General structures of the image forming
apparatus and process cartridge; (2) Frame structure
of the developing means; (3) Shutter structure; and
(4) Structure for installing or removing the
cartridge.
{General Structure}
The overall structures of the electro-
photographic image forming apparatus and processcartridge will be described referring to Figures 1 -
4. Figure 1 is a sectional view of the electro-
photographic image forming apparatus in which the
process cartridge has been installed, and depicts its
overall structure. Figures 2 and 3 are a sectional
and a perspective view of the process cartridge,
respectively, and depict the corresponding structures.
21~793~
--8
Figure 4 is an explanatory drawing, which depicts how
the cover of the image forming apparatus is opened and
the cartridge is installed into the main assembly of
the image forming apparatus.
Referring to Figure 1, this electro-
photographic image forming apparatus A is of a type
which forms an image on recording medium through the
electro-photographic image forming process. First, a
toner image is formed on a drum-shaped electro-
photographically sensitive member (hereinafter,
photosensitive drum) as an image bearing member.
Meanwhile, a sheet of recording medium 2 placed in a
feeder tray 3a is conveyed by a conveying means 3
comprising a pickup roller 3b, conveying roller 3c,
and the like, in synchronism with the toner image
formation. Next, a voltage is applied to a transfer
roller 4 as transferring means, whereby the toner
image formed on the photosensitive drum, which a
process cartridge B comprises, is transferred onto the
recording medium 2. Then, the recording medium having
received the toner image is delivered to a fixing
means 5. This fixing means 5 comprises a driving
roller 5a and a fixing roller 5b containing a heater,
and applies heat and pressure to the recording medium
2 which is passed through the fixing means 5, whereby
the transferred toner image is fixed. Next, the
recording medium 2 bearing now the fixed toner image
21~7936
g
is conveyed, being flipped over while being conveyed,
by discharging rollers 3e and 3f into a discharge tray
6.
In the process cartridge B, the surface of a
photosensitive drum 7 as the image bearing member with
a photosensitive layer is uniformly charged by
applying a voltage to a charging roller 8, which is a
charging means, while the photosensitive drum 7 is
rotated. Next, a laser beam carrying the image data
is projected by an optical system 1 onto the
photosensitive drum 7 through an exposure opening 9,
whereby a latent image is formed on the photosensitive
drum 7. This latent image is developed with toner by
a developing means lO.
The charging roller 8 is placed in contact
with the photosensitive drum 7 to charge the
photosensitive drum 7. The developing means lO
develops the latent image formed on the photosensitive
drum 7 by supplying the toner to the photosensitive
drum 7 on the regions to be developed. The optical
system 1 comprises a laser diode la, a polygon mirror
lb, a lens lc, and a full-reflection mirror ld.
In this developing means lO, the toner within
a toner chamber lOa is supplied to a developing
chamber lOb, and as a developing roller lOc mounted
within the developing chamber lOb is rotated, a layer
of toner charged triboelectrically by a developing
21~793~
--10--
blade lOd is formed on the surface of the developing
roller, in which a magnet is fixed. The toner is
supplied from this toner layer to the photosensitive
drum 7, on the region to be developed. As the toner
is transferred onto the photosensitive drum 7 in
correspondence with the latent image, the latent image
is visualized. In other words, a toner image is
formed on the photosensitive drum 7.
A voltage with a polarity opposite to that of
the toner image is applied to the transfer roller 4,
whereby the toner image on the photosensitive drum 7
is transferred onto the recording medium 2. Then, the
residual toner on the photosensitive drum 7 is removed
by a cleaning means 11. The cleaning means 11
comprises an elastic cleaning blade lla, and the toner
remaining on the photosensitive drum 7 is scraped off
by the elastic cleaning blade lla to be collected in a
waste toner collector llb.
Various components such as the photosensitive
drum 7 are integrated into a form of cartridge, which
is realized by disposing them within a cartridge frame
formed by combining a developing means frame 12, a
developing means wall 13, and a cleaning means frame.
More specifically, the developing means frame 12 and
developing means wall 13 are welded together to form
the toner chamber lOb and developing chamber lOb, and
the developing roller lOb and developing blade lOc are
2147936
--11--
mounted within this developing chamber 10b. On the
cleaning means frame 14, the photosensitive drum 7,
charging roller 8, and various components constituting
the cleaning means 11 are mounted. Finally, the
process cartridge B is formed by pivotably combining
the developing means frame 12 and cleaning means frame
14.
The process cartridge B is provided with an
exposure opening 9, which allows the light beam
carrying the image data to be irradiated onto the
photosensitive drum 7, and a transfer opening 15,
which allows the photosensitive drum 7 to face
directly the recording medium 2 so that the toner
image on the photosensitive drum 7 can be transferred
onto the recording medium 2. Also, the process
cartridge B comprises a shutter member 16, which
exposes or covers the openings 9 and 15.
Referring to Figure 4, the image forming
apparatus A comprises a cover 18, which is mounted on
the apparatus main assembly 17 in such a manner as to
be rotatable about an axis 19. As the rotatable cover
18 is opened, a guiding member 20 (refer to Figure 13)
for guiding the process cartridge B into the apparatus
main assembly is exposed. An operator installs the
process cartridge B, or removes it, along this guiding
member 20.
{Structure of Developing Means Frame}
2147936
-12-
Next, referring to Figures 5 - 7, the
structure of the frame constituting a portion of the
developing means will be described. Figure 5 is a
sectional view of the developing means. Figure 6 is a
perspective view illustrating separately the
developing means frame and developing means wall.
Figure 7 is a perspective view describing how the
developing means frame and developing means wall are
combined.
Referring to Figures 5 and 6, the developing
means 10 comprises the toner chamber lOa and
developing chamber lOb, which are formed by combining
the developing means frame 12 and developing means
wall 13.
The developing means frame 12 constitutes the
main structures of the toner chamber lOa and
developing chamber lOb, and comprises a toner chamber
portion 12b, which is the portion above a seal
mounting portion 12a provided with a toner supplying
opening 12al and constitutes a portion of the toner
chamber lOa, and the developing chamber portion 12c,
which is the portion below the seal mounting portion
12a and constitutes a portion of the developing
chamber lOb. The walls of the toner chamber section
12b and developing chamber portion 12c are opened 12al
(12cl), wherein the toner chamber section 12b is
formed so as for its opening side to taper out, and is
"~ - 1 3 2 1 ~
provided with a toner filling opening (unillustrated)
disposed on one of the longitudinal ends.
The developing means wall member 13 is
combined with the developing means frame 12 in such a
manner as to cover the open side of the developing
means frame 12. It integrally comprises a toner
chamber wall portion 13a, which is to cover the
opening of the toner chamber portion lOa of the
developing means frame 12, and a developing chamber
wall portion 13b, which is to cover the opening of the
developing chamber portion lOb. A recessed portion
13al, which causes the toner chamber wall portion 13a
recessed from the developing chamber wall portion 13b,
is provided at the border line between the toner
chamber wall portion 13a and developing chamber wall
portion 13b.
The developing means frame 12 and developing
means wall member 13 are formed of resin by the
injection molding.
The aforementioned components are assembled
in the following manner. First, the wall member 13 is
placed in a manner to cover the opening of the frame
member 12, and the joints between them are welded. In
this embodiment, when the frame member 12 and wall
member 13 are joined, an end member 21 is attached at
each of the longitudinal ends of the frame and wall
members 12 and 13, as shown in Figure 7, so that both
21~7936
.
-14-
members 12 and 13 are accurately fixed to each other.
In order to accomplish this placement, boss
holes 12bl and 12b2 are provided on each of the
longitudinal end surfaces of the frame member 12, and
also, boss holes 13c are provided on the each of the
longitudinal end surfaces of the wall member 13. The
end member 21 is provided with bosses 21a as
positioning means which are fitted into the boss holes
12bl, 12b2, and 13c.
When the frame member 12 and wall member 13
are thus combined, the joint between the frame member
12 and toner chamber wall portion 13a is melt-welded,
but the joint between the frame member 12 and
developing chamber wall portion 13b is pressure-welded
with the interposition of a toner leak preventing seal
22 (refer to Figure 5) composed of foamed
polyurethane. Since the joint where the seal 22 is
interposed is not melt-welded, the joint is not as
strong as the melt-welded joint. However, since the
bosses 21a of the end member 21 are fitted into the
correspondent boss holes 12bl, 12b2, and 13c, the
positional relation between the frame and wall members
12 and 13 can be just as firm and reliable as in the
case of the melt-welding, and further, even when a
torsional force or the like is applied on the joint,
no gap is liable to be generated at the joint; in
other words, no toner is liable to leak from the
21479~6
-15-
joint.
Further, the end member fixes the positional
relation between the frame member 12 and the
developing roller lOc when the latter is mounted on
the former, and also, functions as a positioning
member when the cleaning means frame 14 is connected
to the frame member 12, to which the wall member 13
has been welded.
When the frame member 12 and wall member 13
are joined as described above, the bottom end portion
of the toner chamber wall portion 13a is disposed
substantially level with the longitudinal edge of the
toner supplying opening 12al (refer to Figure 5) since
the recessed portion 13al is provided on the wall
member 13. The opening 12al is sealed by attaching a
sealing member 23 to the toner supplying opening 12al
by gluing, welding, or the like means, and the
developing roller lOc and developing blade lOd are
mounted in the developing chamber lOa. After the
developing means lO is assembled in this manner, toner
T is filled into the toner chamber lOa through the
aforementioned toner filling opening, and the toner
filling opening is sealed with a cap (unillustrated),
completing the production of the developing means 10.
Next, the cleaning means frame, to which the
photosensitive drum 7, cleaning means 11, and the like
have been mounted, is connected to the integrated
21~936
-16-
frame and wall members 12 and 13, finishing assembling
the process cartridge B.
Referring to Figure 5, the frame member 12 is
formed so as for the toner chamber lOa to be above the
developing chamber lOb, and for a portion of the toner
chamber lOa to project toward the photosensitive drum
7 slightly beyond the developing chamber lOb.
In this embodiment, the first frame (frame
member 12) comprises: a toner storing portion (toner
chamber portion 12b) for storing the toner to be used
for development; an opening portion 12bl of the toner
storing section; and a toner supplying opening 12al,
which allows the toner stored in the toner storing
portion to be supplied to the developing station. The
second frame member (wall member 13) comprises: a
developing means mounting portion 13d where the
developing roller lOc as the developing means is
mounted; and a cover portion (toner chamber wall
portion 13a), which closes up the opening portion 12bl
of the toner storing section. The first and second
frames are joined to form a developing means frame.
In other words, the developing means frame of this
embodiment comprises: the first frame (frame member
12), which includes a toner storing portion, and a
developing portion (a portion where the developing
means mounting portion 13d is provided) for developing
the latent image formed on the photosensitive drum 7,
21~7936
-17-
with the toner stored in the toner storing section,
and extends from the toner storing section to the
developing section (region directly facing the
developing station; and the second frame (wall member
13), which extends from the developing section to the
toner storing section (region correspondent to the
toner storing section).
The first frame is provided with a developing
blade mounting portion where a developing blade lOdl
for regulating the amount of the toner, which adheres
to the circumference of the developing roller lOc
mounted on the developing means mounting section 13d
of the second frame, is mounted. The wall portion
lOal of the toner storing portion of the first frame
is slanted toward the toner supplying opening 12al so
that the toner within the toner storing section is
supplied to the developing region without waste. The
sealing member 27 for sealing the toner supplying
opening 12al is removably attached to the toner
supplying opening 12al. Therefore, the toner within
the toner storing section is prevented from leaking
out before the process cartridge B is put to use.
This sealing member 27 is to be removed by the
operator before the process cartridge is used.
The cover portion of the second frame member
(toner chamber wall portion 13a) is provided with a
slanted surface 13a2, which is slanted toward the
21~7936
toner supplying opening 12al when the first and second
frames are joined. The location of the bottom end
portion 13a3 of the this slanted surface 13a2
substantially coincides with the location of the edge
portion of the toner supplying opening 12al.
Therefore, the toner within the toner storing section
can be supplied to the developing region without being
wasted.
When the first and second frames are joined,
they are joined on the side where the toner storing
portion is formed, that is, by the sides 12f and 13f,
respectively. They may be joined by melt-welding (for
example, ultrasonic welding), gluing, small screws and
nuts, spring clips, or the like means. Further, an
end member 21 is provided for joining the first and
second frames, and it is fitted at each of the
longitudinal ends of the first and second frames. The
end member 21 is provided with boss holes, into which
bosses 2la provided as the positioning means on the
first and second frame, on each of the longitudinal
end surfaces, are fitted to fix the positional
relation between the first and second frames.
Further, when the first and second frames are joined,
an elastic sealing member (toner leak preventing seal
22) is interposed on the side where the developing
means mounting portion 13d is provided.
Both of the first and second frames are
-lg- 21~9~
integrally formed of plastic material (for example,
highly impact resistant styrene).
Therefore, the internal volume of the toner
chamber lOa can be increased to store more toner
without increasing the size of the process cartridge
B. In addition, since the toner chamber portion lOa
of the frame member 12 is formed so as for its open
side to taper out, it can be formed of resin material
or the like by injection molding.
As the sealing member 27 is peeled off when
the process cartridge B begins to be used, the toner
within the toner chamber lOa is supplied from the
toner chamber lOa to the developing chamber lOb due to
its own weight; therefore, it is unnecessary to
provide a dedicated toner sending member. Further,
when the process cartridge B is in the image forming
apparatus A (in the state illustrated in Figure 5),
the seal mounting portion 12a slopes down towards the
right, and the toner chamber wall portion 13a is
placed substantially level with the right-hand edge
portion of the toner supplying opening 12al due to the
provision of the recessed portion 13al on the wall
member 13; therefore, the toner does not remain on the
back side of the seal mounting portion 12a.
It is preferable that the joint between the
frame and wall members 12 and 13 is melt-welded as
described before so that the joint is reliably sealed
-20- 2147936
to prevent the toner leak or the like. However, they
may be joined by means different from the melt-
welding; they may be joined with small screws and
nuts, hooks, with interposition of the sealing
material such as foamed polyurethane or the like in
the joint portion, or may be joined by gluing or the
like means.
{Structure of Shutter}
Next, the shutter structure will be described
referring to Figures 8 - 11. Figure 8 is a
perspective view of the shutter member. Figure 9(a)
is a plan view of the shutter member as seen from the
crosswise direction; Figure 9(b) is a side view of the
shutter member as seen from the longitudinal
direction. Figure 10 is a sectional view of the open
shutter member. Figure 11 is a perspective view of
the open shutter member.
At the upper portion of the frame of the
aforementioned process cartridge B, an exposure
opening 9 is provided, and at the bottom portion, a
transfer opening 15 for transferring the toner image
formed on the photosensitive drum 7 onto the recording
medium 2 is provided. These openings 9 and 15 are
exposed or covered by the shutter member 16. In the
embodiment, which will be described below, both of the
openings 9 and 15 are formed by cooperation of the
developing means frame 12 and cleaning means frame 14.
-- 21 2 1~ 9 3 6
Referring to Figures 8 and 9, the shutter
member 16 integrally comprises the first shutter
portion 16a, which exposes or covers the exposure
opening 9, and the second shutter portion 16b, which
exposes or covers the transfer opening 15. The damage
to the surface of the photosensitive drum 7, adhesion
of foreign matter such as dust to the photosensitive
drum 7, optical aging of the photosensitive material,
and the like, can be prevented by these shutter
portions 16a and 16b.
Referring to Figures 9(a) and 9(b), this
shutter member 16 comprises a rotational axis 16c,
which is provided at each of the longitudinal ends.
The first shutter portion 16a diagonally extends from
the axis 16c in the inclined downward direction, and
the second shutter portion 16b is disposed in such a
manner as to bridge two arm portions 16d, which extend
from the correspondent axes 16c in the direction
opposite to the shutter portion 16a, and then, curve
downward and to the right following the contour of the
cleaning means frame 14.
Referring to Figure 2, a bearing section 14a
with a U-shaped cross-section is provided on the
cleaning means frame 14, on the upper portion at each
of the longitudinal ends. The rotational axis 16c of
the shutter member 16 is fitted into this bearing
section 14a; in other words, the shutter member 16 is
-22- 21479~6
mounted so as to be rotatable around the third frame
14. A torsional coil spring 23 is attached to one of
the rotational axes 16c, which provides a force to
pressure constantly the shutter member 16 in the
direction of closing the openings 9 and 15.
The U-shaped groove of the bearing section
14a is formed in an elastically deformable manner,
with its opening being narrower than the groove
itself; therefore, the shutter member 16b can be
simply attached just by snapping in the axis 16c from
above by force. In other words, the axis 16c is
retained in the U-shaped bearing section 14a by the
elasticity of the bearing section, and it can be
easily pulled out of the bearing section 14a.
An engagement projection 16e is provided at a
predetermined location of the aforementioned arm
portion 16d. As the process cartridge B is inserted
into the image forming apparatus A as will be
described later, the engagement projection 16e engages
with the engagement portion 13a of the main assembly
of the apparatus A, whereby the shutter member 16 is
rotated about the axis 16c. As a result, the first
shutter portion 16a exposes the exposure opening 9,
and at the same time, the second shutter portion 16b
exposes the transfer opening 15.
More specifically, the projection 16e is
provided on the lateral end of the arm portion 16d,
-23- 21 47 9 36
which is one of the arm portions. As the process
cartridge B is installed into the main assembly of the
apparatus A, the projection 16e comes in contact with
the engagement portion 13a provided on the main
assembly of the apparatus A, and engages with it,
being thereby subjected to a force which works in the
direction of opening the shutter member 16. It should
be noted here that the projection 16e projects outward
in the axial direction of the photosensitive drum.
The first shutter portion 16a, which exposes
or covers the exposure opening 9, and the second
shutter portion 16b, which exposes or covers the
transfer opening 15, are integrally formed as
described above. Therefore, it is unnecessary to
employ a complicated link mechanism, which not only
allows the reduction in the component count of the
shutter member 16, but also simplifies the assembly
process of the shutter member 16. Further, the
shutter member can be more reliably opened or closed.
Referring to Figure 11, the arm portion 16d
is made of thin plate material, and is formed to
follow the external contour of the cleaning means
frame 14. At the longitudinal lateral end portion of
the cleaning means frame 14, a recessed portion 14b is
formed, the depth of which matches the thickness of
the arm portion 16d. Therefore, when the shutter
member is in the closed state, the arm portion 16d is
~ -24- 2 1 4~ 9 3 6
fitted in the recessed portion 14b, with the external
surface of the arm portion being substantially level
with the external surface of the cleaning means frame
14.
With the above described arrangement, the arm
portion 16b does not project from the cartridge frame
in the longitudinal direction, nor above the external
surface of the cleaning means frame. Therefore, not
only can the cartridge B size be reduced in the
longitudinal direction, but also, its overall size can
be reduced.
Referring to Figure 1, as the process
cartridge B of this embodiment is installed into the
image forming apparatus A, the shutter member 16 is
rotated, whereby the second shutter portion 16b is
moved to a position above the fixing means 5. This
fixing means 5, which contains a heater, generates
heat, but an air passage is created between the second
shutter portion 16b and cleaning means frame 14,
allowing thereby the air heated by the fixing means 5
to flow upward; therefore, the heat generated by the
fixing means 5 can be easily discharged to prevent the
internal temperature increase of the apparatus.
Further, the shutter member 16 comprises
reinforcing ribs 16f, which are provided on the edge
of the arm portion 16d, and edges, or their
adjacencies, of the shutter portions 16a and 16b.
-25- 21~79~6
As described above, the shutter member 16 of
this embodiment comprises the first and second shutter
portions 16a and 16b, and axis 16c, which are
integrally formed. The axis 16c is the rotational
center, about which the shutter member 16 attached to
the cleaning means frame 14 rotates, and also, is the
engagement portion, with which the shutter member 16
is attached to the cleaning means frame 14. The
second shutter portion 16b is connected to the axis
16c with the arm portion 16d, wherein the
configuration of the arm portion 16d is such that it
matches the contour of the external wall surface of
the process cartridge B when the shutter member 16 is
mounted on the cleaning means frame 14. The arm
portion 16d is located at each of the longitudinal
ends of the second shutter portion 16b. The shutter
member 16 is a single piece component of plastic
material (for example, highly impact resistant styrene
or the like). In other words, the first and second
shutter portions 16a and 16b, axis 16c, arm portion
16d, projection 16e, and ribs 16f are integrally
formed of plastic material.
{Structure for Installing or Removing Cartridge}
Referring to Figure 4 and Figures 12 - 17,
the structure for installing the process cartridge B
into the image forming apparatus A, or removing it
therefrom, will be described. Figure 12 is a side
2147936
view of the process cartridge. Figure 13 is a
sectional view of a cartridge installation guide.
Figures 14 - 16 are explanatory drawings for depicting
how the cartridge B is taken out. Figure 17 is an
explanatory drawing for depicting how the cartridge B,
which has a knob disposed at a position other than on
the top, is removed.
In Figures 14 - 16, alphanumeric references
Pl and P2 designate the directions in which the
process cartridge B is installed into, or removed
from, the apparatus main assembly, respectively. In
this embodiment, the process cartridge B is installed
into, or removed from, the apparatus main assembly in
the direction perpendicular to the axial direction of
the photosensitive drum 7 as shown in Figure 4, with
the developing means frame 40 side being placed to the
front and the cleaning means frame 14 side being at
the rear.
Referring to Figure 12, the process cartridge
B comprises a first projection 24, which is disposed
at each of the longitudinal end surfaces of the
cleaning means frame 14 to fix the position of the
cartridge B, and a second projection 25, which
maintains the orientation of the cartridge B. The
first projection 24 is in line with the rotational
axis of the photosensitive drum 7, and the second
projection 25 is located behind the first projection
~- -27- 2147936
24 relative to the direction Pl, in which the process
cartridge B is installed into the apparatus A.
Further, the cleaning means frame 14 of this
embodiment has a knob 26, which is integrally formed
with the cleaning means frame 14. The knob 26 is
disposed so as to be positioned above a line C - C,
which connects the centers of the first and second
projections 24 and 25.
On the other hand, the image forming
apparatus A is provided with a cover 18, which is
pivotally opened or closed about the axis 19. As the
cover 18 is opened (Figure 4), a space reserved in
apparatus main assembly for accommodating the
cartridge is exposed, wherein an installation guide
member 20 as the cartridge installing means, such as
the one shown in Figure 13, is provided at each of the
lateral sides of the space. This guide member 20 has
a guide groove 20a, which extends in the diagonally
downward direction to guide the first and second
2~ projections 24 and 25 of the process cartridge B, and
at the bottom end of the guide groove 20a, a
positioning recess 20b is provided.
Referring to Figure 16, first, an operator
grabs the knob 26 and engages the first projection 24,
which is provided at each of the longitudinal end
surfaces of the process cartridge B, into the groove
20a. Next, as the operator inserts the process
214793~
-28-
cartridge B further into the image forming apparatus A
along the groove 20a, the second projection 25
provided at each of the longitudinal end surfaces of
the process cartridge B engages with the groove 20a.
Then, the process cartridge B is further inserted
along the groove 20a with the first and second
projections 24 an 25 being engaged in the groove 20a.
As the process cartridge B is inserted to the deepest
point, the first projection 24 comes in contact with
the wall 20b at the deepest end of the groove 20a as
shown in Figure 15. Then, the process cartridge B is
slightly rotated by its moment in the clockwise
direction (in the direction of an arrow a in Figure
15) about the second projection 25. As a result, the
first projection 24 drops into the recess 20b, fixing
thereby the position of the process cartridge B, which
concludes the installation of the process cartridge B.
The orientation of the process cartridge in the
apparatus A is maintained by the second projection,
which is in engagement with the guide groove 20a.
Further, the process cartridge B rotates only slightly
to drop into the recess 20b; therefore, when a helical
gear 7a provided at one of the longit~l~i n~ ends of
the photosensitive drum 7 meshes with a helical gear
21 provided on the main assembly of the apparatus A,
the gears are not likely to be damaged. Further,
since the process cartridge B is rotated upward when
214793~
-29-
it is removed from the main assembly of the apparatus
A, the gears can be smoothly disengaged. The helical
gear 21 transmits the driving force of a motor
(unillustrated) provided on the apparatus main
assembly to the photosensitive drum 7.
Next, steps for taking the process cartridge
B out of the image forming apparatus in order to
exchange the process cartridge B will be described.
When an attempt is made to simply pull the
cartridge B out of the apparatus A, it is not going to
be successful since the first projection 24 is in
engagement with the recess 20b. Therefore, it is
necessary to dissolve the engagement between the first
projection 24 and positioning recess 20b before
attempting to pull out the cartridge B. According to
this embodiment, this state of engagement can be
released in relation to the action for simply pulling
out the cartridge B.
More specifically, as the operator pulls the
knob 26 of the process cartridge B of this embodiment
toward him/her in order to remove the process
cartridge B, the process cartridge B is rotated
counterclockwise (in the direction of an arrow b in
Figure 15) about the second projection Z5, whereby the
engagement between the projection 24 and recess 20b is
simply dissolved. In other words, as the knob 26 is
pulled in the arrow P2 direction as shown in Figure
21479~6
-30-
14, a force equivalent to an x-component Px of the
force P2 is imparted on the first projection 24,
generating thereby a rotational moment about the
second projection 25, and at the same time, the first
projection 24 is lifted by a y-component Pxy of the
force Px, whereby the engagement between the
projection 24 and positioning recess 20b is dissolved
as shown in Figure 15. In this state, the knob 26 is
pulled in the arrow P2 direction, whereby the process
cartridge B can be pulled out with the first and
second projections 24 and 25 sliding along the guide
groove 2Oa.
In other words, the operator can simply take
the process cartridge B out of the image forming
apparatus A just by pulling the knob 26 in the arrow
P2 direction.
On the contrary, when the knob 26 is disposed
below the line C - C connecting the centers of the
first and second projections 24 and 25 as shown in
Figure 17, the process cartridge B does not rotate
about the second projection 25 even if the operator
pulls the knob 26 in the arrow P2 direction;
therefore, the engagement between the first projection
25 and positioning recess 20b is not dissolved. In
such a case, the process cartridge B cannot be taken
out unless the projection 26 is pushed down in the
direction of an arrow Q to break the engagement
-31- 21~7936
between the projection 24 and recess 20b, and then, is
pulled in the arrow P direction.
It is easily understandable from the above
description that the structure of this embodiment, in
which the knob 26 is disposed above the line C - C
connecting the centers of the first and second
projection 24 and 25, is advantageous since the
process cartridge B can be simply taken out just by
applying a force to the process cartridge B in the
direction in which the cartridge B is taken out.
Further, forming integrally the first and
second projections 24 and 25, and the knob 26 on the
same member, that is, the cleaning means frame 14, can
improve accuracy in the positional relationship among
the components, eliminating thereby the loose fit
associated with the first and second projection 24 and
25, and the knob 26.
{Other Embodiments}
Next, referring to Figures 18 - 20, the other
embodiments of the present invention will be described
regarding: (1) Frame structure of the developing
means; (2) Shutter structure; and (3) Structure for
installing or removing the cartridge, in this order,
and then, (4) Structures of various other components
will be described, wherein the components having the
same functions as those of the first embodiment will
be designated with the same reference symbols to
_ 32 21~7 93 6
eliminate the duplication of the description.
{Other Embodiments of Frame Structure of Developing
Means}
In the first embodiment, when the frame
member 12 and wall member 13 is joined, only the joint
between the frame member 12 and toner chamber wall
portion 13a is melt-welded, and the end member 21 is
attached at each of the longitudinal end surfaces of
both frame and wall members in order to fix the
positional relationship between two components 12 and
13 (refer to Figure 7). However, the frame member 12
and wall member 13 may be joined by melt-welding the
entire joint between the two members 12 and 13.
With such an arrangement, the two members 12
and 13 are more firmly joined, which can prevent the
component displacement caused by the torsional force.
In this case, it is unnecessary to interpose the toner
leak prevention seal 22 at the joint where the
developing chamber wall portion 13b of the wall member
13 is joined with the frame member 12. Therefore, the
component count can be reduced, which in turn reduces
the assembly steps.
Further, in the first embodiment, the seal
mounting portion 12a is provided on the frame member
12, and the sealing member 27 is mounted on this seal
mounting portion 12a by gluing, melt-welding, or the
like means to seal the toner supplying opening 12al.
21~7936
-33-
However, the sealing member 27 may be simply pinched
in as shown in Figure 18.
The frame member 12 illustrated in Figure 18
comprises the seal mounting portion 12a with the toner
supplying opening 12al, which is similar to the
arrangement in the first embodiment. However, in this
embodiment, a seal retaining portion 28, which can
join with the seal mounting portion 12a when the frame
and wall members 12 and 13 are joined, is provided on
the wall member 13, between the toner chamber wall 13a
and developing chamber wall 13b. This seal retaining
portion 28 is provided with a toner supplying opening
28a, the size and location of which coincides with
those of the toner supplying opening 12al.
The frame member 12 and wall member 13 are
joined with small screw 30 with the interposition of a
toner leak prevention seal 29, which is composed of
foamed polyurethane or the like, at the interface.
The sealing member 27 is retained at a
predetermined location by being interposed between the
seal mounting portion 12a and seal retaining portion
28 when the frame member 12 and wall member 13 are
joined. Therefore, it is unnecessary to attach the
sealing member 27 by gluing, melt-welding, or the like
means, which makes it easier to remove the sealing
member 27 when the cartridge usage begins, and also,
makes it easier to recycle the frame member 12 and
_34_ 21479~
wall member 13 since they are not contaminated with
adhesive residue, welding residue, or the like.
Further, regarding the provision of the seal
retaining portion 28 on the wall member 13, a hinge
portion 31 may be provided at the border portion
between the toner chamber wall portion 13a and
developing chamber wall portion 13b to permit hinge
motion.
The structure illustrated in Figure 19 is
different from that illustrated in Figure 18 in that
there is a bendable hinge portion 31 between the toner
chamber wall portion 13a and developing chamber wall
portion 13b of the wall member 13, and that when the
frame member 12 is joined with the wall member 13, the
joint between the frame member 12 and toner chamber
wall portion 13a is melt-welded, but a toner leak
prevention seal 32 composed of foamed polyurethane or
the like is interposed at the joint between the frame
member 12 and developing chamber wall portion 13b.
In this case, the sealing member 27 can be
simply pinched between the seal mounting portion 12a
and seal retaining portion 28 just by bending the
developing chamber wall portion 13b after melt-welding
the joint between the frame member 12 and the toner
chamber wall portion 13a of the wall member 13 during
the assembly of the cartridge.
In the case of such a design as described
~- 21~7936
-35-
above in which the wall member 13 is provided with the
hinge portion 31, the position of the toner chamber
wall portion 13b is fixed in a state of being bent at
the hinge portion 31; therefore, it is necessary to
maintain the angle of the hinge portion 31 by
attaching the end member 21 with the positioning
bosses, at each of the longitudinal ends of the frame
and wall members 12 and 13, after joining them in the
same manner as the first embodiment.
Hereinbefore, the frame structure of the
developing means was described with reference to the
process cartridge including the one in the first
embodiment, but such a structure is similarly
applicable to developing apparatuses comprising a
toner chamber, and a developing chamber in which a
developing roller, a developing blade, and the like,
are mounted, and the same effects can be expected.
{Other Embodiments of Shutter Structure}
In the case of the first embodiment described
above, the shutter member 16 is of a single piece
comprising integrally the first shutter portion 16a,
which exposes or covers the exposure opening 9, and
the second shutter portion 16b, which exposes or
covers the transfer opening 15 (refer to Figures 8 and
9). However, the first and second shutter portions
16a and 16b may be separate members as shown in Figure
20.
-36- 2147~36
In the case of the shutter structure
illustrated in Figure 20, the first shutter portion
16a, which exposes or covers the exposure opening 9,
and the second shutter portion 16b, which exposes or
covers the transfer opening 15, are separate members,
both of which are rotatively supported by the bearing
portions provided the top portion of the cleaning
means frame 14, and are under a constant pressure,
which is generated by an unillustrated spring in the
closing direction.
As for the opening or closing means of the
first shutter portion 16a, an arc-shaped link portion
33 is provided, which is integrally formed with the
second shutter portion 16b. Therefore, as the second
shutter portion 16b is opened, the link portion 33
moves together to push down the first shutter portion
16a, opening thereby the first shutter portion 16a,
and as the second shutter portion 16b is closed, the
link portion 33 ceases holding down the first shutter
portion 16a, allowing thereby the first shutter
portion 16a to close.
Also, the above described structure makes it
possible to interlock the opening or closing movement
of the first shutter portion 16 with the opening or
closing movement of the second shutter portion 16b;
therefore, the shutter portions can be reliably opened
or closed without the provision of a complicated
-37- 2147936
mechanism for opening or closing the shutter portions.
Even in the case of the structure illustrated
in Figure 20, the second shutter portion 16b is formed
so that its arm portion 16d does not project beyond
the longitudinal end portions of the cartridge frame,
and the second shutter portion 16b forms the air
passage for releasing the heat generated by the fixing
means 5. Therefore, the same effects as the first
embodiment can be expected.
~Other Embodiments of Structure for Installing or
Removing Cartridge}
In the first embodiment, the removal of the
process cartridge B from the image forming apparatus A
is made easier by providing the cleaning means frame
14 with: the first and second projections 24 and 25,
which are disposed on each of the longitudinal end
surfaces; and the knob 26, which is disposed above the
line connecting the projections 24 and 25, wherein, as
the knob 26 is pulled, the cartridge B is rotated
about the second projection, whereby the engagement
between the first projection 24 and the recess portion
20b is broken (refer to Figure 14).
However, when the process cartridge B is to
be removed, the operator can dissolve the engagement
between the first projection 24 and recess portion 20b
by holding the cartridge frame instead of the knob 26
and rotating the cartridge B about the second
2147936
-3~-
projection 25. After the engagement is broken, the
cartridge B can be easily pulled out.
In other words, the process cartridge B can
be taken out without the provision of the knob 26,
just by rotating the process cartridge about the
second projection 25.
Next, another embodiment of process cartridge
B will be described.
Figure 21 is a cross-sectional view of
another embodiment of the process cartridge B. Figure
22(a) is a left side view of the cleaning means frame
14 of the process cartridge B; Figure 22(b) is a right
side view thereof. Figure 23 is an explanatory
drawing depicting how the process cartridge according
to the present invention is inserted into, or removed
from, an electro-photographic image forming apparatus.
Figure 24 is a side view of the process cartridge,
describing the moment working during the cartridge
insertion. Figure 25 is a side view of the process
cartridge, describing the moment working during the
removal thereof. The members having the same
functions as those in the first embodiment are
designated with the same reference symbols to avoid
duplicating the same descriptions. It should be noted
that a toner stirring means lOa5 is provided in the
cartridge of this embodiment.
Referring to Figure 22, the process cartridge
21~7936
-39-
employed în this embodiment comprises a left side
frame portion 14c (first frame portion), which is
located on the left end in the axial direction of the
photosensitive drum 7 (Figure 22(a)), and a right side
frame portion 14d (second frame portion), which is
located on the other end (Figure 22(b)). The frame
portion 14c is provided with a first projection 24a
(first projection 24) and a second projection 25a
(second projection 25), both of which project outward.
The frame portion 14d is provided with a third
projection 24b (first projection 24) and a fourth
projection 25b (second projection 25), both of which
also project outward. The first and third projections
fix the position of the process cartridge B when the
cartridge B is installed into the apparatus A main
assembly, and the second and fourth projections serve
as the rotational center of the process cartridge when
the cartridge B is taken out of (installed into) the
apparatus A main assembly. The first and third
projection (first projection 24) are disposed in line
with the axial line of the photosensitive drum 7; more
specifically, they are cylindrical members formed in
such a manner as to fit coaxially around the drum
shaft of the photosensitive drum 7. Referring to
Figure 22(a), a metallic drum shaft 7c supporting the
photosensitive drum 7 on the left side frame portion
14c projects beyond the first cylindrical projection
214~93~
-40-
24a, and as the process cartridge B is inserted into
the apparatus A mains assembly, this drum shaft 7c
comes in contact with an electrically conductive
member (metallic plate spring 50 illustrated in Figure
23(a) - 23(c)) to ground the photosensitive drum 7.
Referring to Figure 22(b), an alphanumeric reference
7d designates a metallic drum, which supports the
photosensitive drum 7 on the right side frame portion
14d. Further, the left and right frame portions 14c
and 14d are provided with a fifth projection 14cl and
a sixth projection 14dl, respectively, which also
project outward. The fifth projection 14cl bridges
between the peripheral surfaces of the first and
second cylindrical projections 24a and 25b, and the
sixth projection 14dl bridges the peripheral surfaces
of the third and fourth cylindrical projections 24b
and 25b. These fifth and sixth projections 14cl and
14dl prevent the cartridge B from being over-rotated
when the operator takes his/her hand off the knob 26
by mistake immediately after he/she begins to insert
the process cartridge B into the apparatus A main
assembly, or immediately before he/she finishes
removing the cartridge (state illustrated in Figure
16). Further, when the process cartridge B is
oriented, as shown in Figure 21, so as for the
photosensitive drum 7 to be positioned toward bottom,
the second cylindrical projection 25a is above the
2147936
-41-
first cylindrical projection 24a; the fourth
cylindrical projection 25b is above the third
cylindrical projection 24b; the second cylindrical
projection 25a is on the upstream side of the first
cylindrical projection 24a relative to the direction
in which the process cartridge B is inserted into the
apparatus A main assembly, and in the same manner, the
fourth cylindrical projection 25b is disposed on the
upstream side of the third cylindrical projection 24b.
The first and third cylindrical projections 24a and
24b are the same in external diameter, whereas the
external diameter of the second cylindrical projection
25a is larger than that of the first cylindrical
projection 24a (also, the third cylindrical projection
24b), and the external diameter of the fourth
cylindrical projection 25b is larger than that of the
second cylindrical projection 25a. This arrangement
of differentiating the sizes of the cylindrical
projections can accomplish so-called three point
support of the process cartridge B in the apparatus A
main assembly (state illustrated in Figure 14 and
Figure 23(c)), which improves the positioning accuracy
of the process cartridge in the apparatus A main
assembly. As for the actual measurements of these
projections in this embodiment, the external diameters
of the first and third cylindrical projections 24a and
24b are approximately 12 mm (tolerable range of ll.O
-42- 2147 ~6
mm to 12.5 mm); the external diameter of the second
cylindrical projection 24b, approximately 12.5 mm
(tolerable range of 12.0 mm to 13.5 mm); and the
fourth cylindrical projection 25b is approximately
13.0 mm (tolerable range of 12.0 mm to 13.5 mm). The
heights of the first and second cylindrical
projections 24a and 25a are approximately 4.5 mm
(tolerable range of 1.0 mm to 5.5 mm), and the heights
of the third and fourth cylindrical projection are
approximately 4.0 mm (tolerable range of 1.0 mm to 5.0
mm). The height of the fifth projection 14cl is
approximately 3.0 mm (tolerable range of 0.0 mm to 5.5
mm), and the height of the sixth projection 14dl is
approximately 2.5 mm (tolerable range of 0.0 mm to 5.0
mm). It should be noted here that the provision of
the fifth and sixth projections 14cl and 14dl is not
mandatory. A distance L between the centers of the
first and second cylindrical projections 24a and 25a,
or between those of the third and fourth cylindrical
zo proiections 24b and 25b, is approximately 34 mm. The
cleaning means frame 14 constituted integrally of the
left side frame portion 14c (first frame portion) and
right side frame portion 14d (second frame portion)
contains the photosensitive drum 7, charging means
(for example, charging roller 8), and cleaning means
(for example, elastic cleaning blade lla), whereas the
developing means frame 40 (second cartridge frame)
_43 2 14~ 936
contains the developing means (for example, developing
roller lOc) and toner storing portion (for example,
toner chamber 12b). The cleaning means frame 14 and
developing means frame 40 are joined pivotally from
each other. An alphanumeric reference 14al designates
a groove, with which the engagement projection 16e
engages.
Referring to Figures 23(a) - 23(c), steps for
installing the process cartridge B into the main
assembly of the apparatus A, or removing it therefrom,
will be described.
In the same manner as the aforementioned
embodiment, the first projection 24 (24a and 24b) and
second projection 25 (25a and 25b) are fitted into the
guide groove 20a and inserted farther into the
apparatus along this groove 20a. As the cartridge B
is inserted to the deepest point, the first projection
24 (24a and 24b) drops into the positioning recess
20b, fixing thereby the position of the cartridge B.
At this time, the second projection 25 (25a and 25b)
remains in the guide groove 20a, whereby the proper
orientation of the cartridge B is maintained. Also,
at this time, the position of the process cartridge B
of this embodiment is fixed by the so-called three
point support; therefore, the position of the
cartridge B in the apparatus A main assembly is more
precisely fixed. Further, in this embodiment, the
214793~
-44-
first projection 24 (24a and 24b), which is disposed
in line with the axial line of the photosensitive drum
7, is dropped into the recess 20b, and this first
projection 24 (24a and 24b) is retained in the recess
20b by a direct pressure. More specifically,
referring to Figure 23, a torsional coil spring 20d as
a pressing means is mounted on a projection 20c
provided on an installation/removal guide 20. One end
of the spring 20d is anchored at a stopper 20i and the
other is anchored at a stopper 20j, so that a portion
of the torsional coil spring 20d project into the
space above the positioning recess 20b.
With such an arrangement being in place, as
the process cartridge B is inserted along the guide
groove 20a of the guide member 20 as illustrated in
Figure 23, one end of the torsional coil spring 20d
comes in contact with the stopper 20j as illustrated
in Figure 22(a), and as the cartridge B is farther
inserted, the first projection 24 (24a and 24b) is
caused to push the torsional coil spring 20d as
illustrated in Figure 22(b), whereby the one end of
the spring 20d becomes separated from the stopper 20c,
generating thereby such a force that presses down the
first projection 24 (24a and 24b). Then, as the
cartridge B is farther inserted, the first projection
24 (24a and 24b) drops into the positioning recess
20b, as shown in Figure 23, concluding thereby the
214~936
installation of the cartridge B. At this time, the
first projection 24 (24a and 24b) is under the
downward pressure from the spring 20d, being thereby
pressed upon the abutting portion 20bl of the
positioning recess 20b. Therefore, the first
projection 24 (24a and 24b) is securely held in the
positioning recess 20b.
As described above, the first projection 24
(24a and 24b) disposed in line with the axial line of
the photosensitive drum 7 is directly pressed down by
the spring 20d; therefore, the positioning of the
photosensitive drum 7 in the apparatus A main assembly
becomes more accurate by being direct.
Next, referring Figure 24, the moment, which
works to drop the first projection 24 (24a and 24b)
into the recess 20b, will be described.
As an operator inserts the cartridge into the
apparatus A through an opening 20e toward the
positioning portion 20b (diagonally downward), holding
the knob and using a force P, the first and second
projections 24 (24a and 24b) and 25 (25a and 25b) are
slid along the cartridge guide 20, wherein the first
projection 24 is guided till it comes in contact with
the deepest end 20al of the guide groove 20a, above
the positioning portion 20b. At this point, the
cartridge B begins to rotate about the second
projection due to a y-component Py of the force P
2147936
.
-46-
imparted on the first projection 24. As a result, the
first projection 24 is engaged into the positioning
portion 20b, ending the installation of the process
cartridge B.
Next, referring to Figure 25, the moment
which works when the cartridge B is taken out, will be
described. When the cartridge B is taken out of the
apparatus main assembly, the steps illustrated in
Figures 23(c), 23(b) and 23(a) are followed in this
order.
As the operator pulls the knob 26 toward the
opening 20e of the cartridge guide 20a (diagonally
upward), using a force P, a rotational moment
equivalent to the x-component Px of the force P is
generated about the second projection 25 (25a and
25b), and is imparted on the first projection 24 (24a
and 24b). As a result, the first projection 24 is
lifted, whereby the engagement between the positioning
portion 20b and first projection 24 is broken. In
other words, the cartridge B is rotated
counterclockwise about the second projection 25.
Then, as the operator pulls the knob 26
further toward him/her, the cartridge B comes out of
the apparatus A main assembly with the first and
second sliding along the cartridge guide 20a.
Further, in this embodiment, a shutter guide
portion 20i is provided on the upper surface of the
- 21~7936
-47-
guide member 20, extending diagonally upward relative
to the process cartridge B inserting direction. This
shutter guide portion 20i is a portion with which a
shutter projection 16e provided on the shutter arm 16d
of the process cartridge B comes in contact. More
specifically, as the process cartridge B is inserted
along the guide groove 20a, the shutter projection 16e
comes in contact with the guide portion 20i, and as
the cartridge B is farther inserted, the shutter
projection is pushed up. As a result, the shutter
member 16 is rotated clockwise against the pressure of
a spring (unillustrated) as shown in Figure 23,
whereby the transfer opening 15 and exposure opening
14 are exposed. On the contrary, when the process
cartridge B is taken out, the shutter projection 16e
is pushed down by the pressure from the spring along
the slanted surface of the guide portion 20i. As a
result, the shutter member 16 is rotated
counterclockwise, covering thereby the transfer
opening 15 and exposure opening 14.
Further, in this embodiment, the first and
second cylindrical projection 24a and 25a and the
fifth projection 14cl are integrally formed with the
left side frame portion 14c, and the third and fourth
cylindrical projections 24b and 25b and the sixth
projection 14dl are integrally formed with the right
side frame portion. In other words, these cylindrical
- - -
214793~
-
-48-
projections 24a, 24b, 25a and 25b and the projections
14cl and 14dl are integrally formed with the cleaning
means frame 14. This cleaning means frame is composed
of plastic material such as highly impact resistant
styrene.
~Other Embodiments of Related Components}
The present invention is preferably
applicable not only to the above described process
cartridge B, which is used to form a monochrome image,
but also to a multicolor process cartridge, which is
used to form a multicolor image (image of two colors,
three colors, or full-color) and comprises two or more
developing means.
As for the developing method, the present
invention is compatible with various well-known
methods such as the double component magnetic brush
developing method, cascade developing method, touch
down developing method, cloud developing method, and
the like.
As for the image bearing member to which the
present invention is applicable, it is not limited to
the aforementioned photosensitive drum. The present
invention is also applicable to the following. To
begin with, the photoconductive material is usable as
the photosensitive material. As for the
photoconductive material, amorphous silicon, amorphous
selenium, zinc oxide, titanium oxide, organic
- 21479~6
-49-
photoconductor, or the like, is usable. Further, as
for the configuration of a base member on which the
photosensitive material is placed, it may be in the
form of a rotary member such as a drum, or may be in
the form of a sheet such as a belt or the like.
Generally speaking, a base member in the form of a
drum or a belt is used. For example, in the case of
the base member of the drum type, the photoconductive
material is coated, deposited, or placed by the like
means on a cylinder of aluminum alloy or the like.
Further, as to the structure of the charging
means, the so-called contact charging method is
employed in the first embodiment, but it is needless
to say that the present invention is also applicable
to other conventional charging methods such as the one
in which a metallic shield of aluminum or the like is
placed on three sides of a tungsten wire; a high
voltage is applied to the tungsten wire to generate
positive or negative ions; and the ions are
transferred onto the surface of the photosensitive
drum to charge it uniformly.
Further, the aforementioned charging means
may be of the blade type, (charging blade), pad type,
block type, rod type, wire type, or the like, in
addition to the roller type described previously.
As for the method for cleaning the residual
toner on the photosensitive drum, the cleaning means
21~793~
-50-
may be constituted of a blade, fur brush, magnetic
brush, or the like.
The process cartridge described above is such
a process cartridge that comprises an electro-
photographic photosensitive member, or the like, andat least one processing means. In other words, the
process cartridge to which the present invention is
applicable may be of a different type other than the
one employed in the above described embodiments. For
example, it may be of such a type that a combination
of: an image bearing member and a charging means; an
image bearing member and a developing means; an image
bearing member and a cleaning means; or an image
bearing member and two or more of the aforementioned
processing means, is integrated into a replaceable
form of cartridge for an image forming apparatus.
In other words, the process cartridge
described above means such a cartridge that a charging
means, a developing means, or a cleaning means is
integrated with an electro-photographic photosensitive
member into a replaceable form of cartridge for an
image forming apparatus; at least one of a charging
means, a developing means, and a cleaning means is
integrated with an electro-photographic member into
the replaceable cartridge; or at least a developing
means and an electro-photographic photosensitive
member are integrated into the replaceable cartridge.
-51- 2147936
In the above described embodiments, a laser
beam printer is described as an example of image
forming apparatus, but the present invention is not
limited to this example. That is, the present
invention is also applicable to other image forming
apparatuses such as electro-photographic copying
machines, facsimile apparatuses, or word processors.
According to the present invention, the
process cartridge is structured in such a manner that
the movement of the first shutter portion, which
exposes or covers the exposure opening, is interlocked
with the movement of the second shutter portion, which
exposes or covers the transfer opening; therefore, it
is unnecessary to provide separate mech~nisms for
opening or closing two shutter portions. As a result,
the shutter portions can be simplified and made more
reliable. Further, the aforementioned integration of
the first and second shutter portions eliminates the
need for a complicated link mechanism. Therefore, not
only can the component count be reduced, but also, the
assembly process can be simplified, which leads to a
cost reduction.
Further, the rotational center of the shutter
member is positioned on top of the cartridge frame;
therefore, the arm portion, which supports the second
shutter portion which exposes or covers the transfer
opening at each of the longitudinal ends, can be
- 2147936
-52-
formed so that it does not project beyond the
longitudinal end of the cartridge frame. As a result,
the cartridge dimension in the longitudinal direction
can be reduced, whereby the cartridge size can be
reduced.
Further, when the process cartridge is
installed into the image forming apparatus main
assembly, the second shutter portion is opened in such
a manner as to form an air passage; therefore, the
heat generated by the fixing means can be effectively
released to prevent the internal temperature increase
of the apparatus.
Further, the process cartridge is structured
so as to comprise the electro-photographic
photosensitive member, developing means, or the like;
therefore, a cartridge capable of recording a highly
precise image can be provided.
Therefore, electro-photographic copying
machines, laser beam printers, or the like
apparatuses, which employ the aforementioned process
cartridge according to the present invention can more
stably record a higher quality image.
Further, in this embodiment, the toner
chamber and developing chamber are constructed by
joining: the open frame member constituting the toner
chamber frame portion and developing chamber frame
portion, which are open on the same side; and the wall
21479~S
.
-53-
member constituting the toner chamber wall portion and
developing chamber wall portion, which are joined with
the corresponding open sides of the frame member.
Therefore, it is possible to form the toner chamber
and developing chamber of a complicated configuration
by joining just two components. As a result, a
developing apparatus or a process cartridge having a
large toner capacity in spite of a smaller size can be
constructed.
Further, the wall member is disposed at the
edge of the toner supply opening, which is located
between the toner chamber and developing chamber;
therefore, the toner is prevented from being
unnecessarily left in the toner chamber, being thereby
used without waste.
Further, the seal retaining portion, which
retains the seal member for sealing the toner supply
opening, is provided on the wall member; therefore,
the sealing member can be easily mounted, and in
addition, when a toner depleted developing apparatus
or process cartridge is recovered for recycling, the
frame member and wall member can be simply recycled.
Further, the wall member constituted of the
toner chamber portion and developing chamber portion
is bendable at the point between two portions;
therefore, a developing apparatus or process cartridge
can be simply assembled.
~-- 2147936
-54-
Further, the end member is attached at each
of the longitudinal ends of the frame member and wall
member to fix the positional relation between the two
members; therefore, the frame member and wall member
can be accurately joined.
Further, the cartridge is structured so as
for the toner chamber constituting a part of the
developing means to be disposed above the developing
chamber; therefore, the toner within the toner chamber
is supplied to the developing chamber by its own
weight, which eliminates the need for the provision of
a toner delivering member.
Further, in the embodiments according to the
present invention, the first projection is disposed in
line with the axial line of the electro-photographic
photosensitive member, and the second projection,
which serves as the rotational center of the
cartridge, is provided; therefore, these projections
serve not only as the guiding members when the process
cartridge is inserted into, or removed from, the image
forming apparatus, but also, the cartridge can be
easily rotated about the second projection when the
cartridge is taken out of the apparatus main assembly
to disengage the first projection, which has dropped
into the positioning recess of the apparatus main
assembly. As a result, the cartridge can be smoothly
pulled out of the apparatus.
- 21~7936
-55-
Further, the second projection is positioned
behind the first projection relative to the cartridge
inserting direction, and the knob is disposed above
the line extended from the line connecting the first
and second projection; therefore, the engagement
between the first projection and positioning recess
can be easily broken just by pulling the knob toward
the operator, and then, the cartridge can be easily
removed by pulling further the knob toward the
operator.
Further, the cartridge installing means
provided in the image forming apparatus is constructed
so that the cartridge is to be inserted in the
diagonally downward direction; therefore, the
cartridge can be smoothly pulled out of the apparatus
by holding the knob.
Further, the first and second projection, and
the knob, are provided on the frame member which holds
the electro-photographic photosensitive member;
therefore, the cartridge can be easily rotated about
the second projection.
Lastly, the process cartridge comprises: a
frame member provided with the projections and knob;
and an electro-photographic photosensitive member, a
developing means, and the like, which are integrally
contained in the frame member; therefore, the electro-
photographic copying machines, laser beam printers, or
2147936
-56-
the like, can stably record a high quality image when
constructed to be compatible with this process
cartridge.
As described in the foregoing, according to
the present invention, there is provided a process
cartridge having a shutter of simple structure, and a
image forming apparatus usable with the process
cartridge.
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.
