Note: Descriptions are shown in the official language in which they were submitted.
~25'9232
The present invention generally relates to a
transfer ribbon feed means and more particularly, to a
transfer ribbon feed arrangement including color-layer
position detecting apparat~s, which is employed, for
example, in a thermal transfer type recording apparatus.
Conventionally, in a thermal transfer type
recording apparatus, for example, a thermal transfer printer
employing a transfer ribbon such as inked ribbon therein,
wrinkling of the ribbon or shears in printing or the like
have been prevented by applying tension to the transfer
ribbon by winding it round a take-up roller connected to a
driving source, with friction being exerted on a shaft of a
transfer ribbon~feed roller.
Furthermore, with respect to a colored transf~r
ribbon, the color of each colored layer or the position
thereof has been detected by forming markers on the colored
transfer ribbon at the portions subjected to no interference
for printing and detecting these markers by an optical
detecting means such as photosensor composed of a light
emitting diode and a phototransistor.
However, since the roll diameter of the transfer
ribbon which is wound round the feed roller and is rolled
round the take-up roller varies with the transportation
thereof, the tension applied on the transfer ribbon can not
be kept constant and accordingly, wrinkling of the transfer
ribbon or shears in printing or the like have still
disadvantageously taken place.
In addition, the color of each colored layer or
the position thereof has not been clearly detected in some
cases due to an improper positioning of any colored layer of
the colored transfer ribbon which results from a slackening
of the ribbon or the like.
~he present application is a divisional of
Canadian Patent Application Serial No. 520,550, filed
35 October 15, 1986.
An object of the invention is to substantially
eliminate the ahove described disadvantages inherent in the
prior art transfer type recording apparatus. A particular
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object of the invention defined in the present application
is to provide an improved transfer type recording apparatus
having a ribbon tensioning means in a ribbon feed
arrangement thereof which is capable of preventing wrinkling
of a transfer ribbon, and shears in printing or the like
from undesirably taking place.
An object of the present invention is to provide
a transfer type recording apparatus of the above described
type which is capable of clearly detecting the color of each
colored layer of a colored transfer ribbon or the position
thereof, with simple markers being formed on a limited space
of the colored transfer ribbon.
The parent application Serial No. 520,550 defines
a transfer ribbon feed arrangement for use in a transfer
type recording apparatus which transfers ink onto a
recording sheet by sequentially feeding said transfer
ribbon, said transfer ribbon feed arrangement comprising: a
feed roller for feeding said transfer ribbon therefrom, a
take-up roller for winding up said transfer ribbon
therearound, and tensioning means disposed on the feed side
of said transfer ribbon for applying a constant load on said
transfer ribbon to keep said transfer ribbon under a
constant tension, said tensioning means comprising at least
a torque limiter for maintaining said constant load.
The present invention provides a method of
sequentially detecting colors and positions of each group of
color-inked layers formed in a manner such that a plurality
of groups of said color-inked layers are successively spread
in a row in a predetermined order on a transfer ribbon in a
lengthwise direction thereof, which ribbon is employed in a
color thermal transfer printer, with a group of said color-
inked layers corresponding to one page of a transfer sheet,
a plurality of positioning markers is formed along one
opposite side edge portion of the colored transfer ribbon so
as to correspond to respective color-inked layers, and a
cuing marker is also formed on said edge portion so as to
correspond to the first color-inked layer in each group,
said method comprising the steps of: detecting a transfer
1~99232
position for each color-inked layer facing a thermal print
head by detecting each positioning marker by a first sensor,
detecting said cuing marker by a second sensor at
the same time as the aforementioned first detecting step,
and judging the color of each color-inked layer
located on said transfer position by the number of
positioning markers detected since said cuing marker has
been detected by said second sensor.
Another aspect of the invention provides in a
color printer employing a transfer ribbon having areas of
differently colored ink which are arranged in succession
along the transfer ribbon and which are arranged in
successive groups along the transfer ribbon, a cuing marker
for each of the groups and a plurality of positioning
markers for each of the groups, said cuing marker being
formed on the ribbon in alignment with a leading one (with
respect to the direction of feed of the ribbon) of the areas
in each group, said positioning markers being equal in
number to the number of the areas in each group and being
formed on the ribbon in alignment with the respective areas
in each group, the improvement comprising sensor means for
detecting said cuing marker and said positioning markers.
A further aspect of the invention provides a
transfer ribbon for use in a color printer, said transfer
ribbon having areas of differently colored ink which are
arranged in succession along the transfer ribbon and which
are arranged in successive groups along the transfer ribbon,
a cuing marker for each of the groups and a plurality of
positioning markers for each of the groups, said cuing
marker being formed on the ribbon in alignment with a
leading one, with respect to the direction of feed of the
ribbon, of the areas in each group, and said positioning
markers being equal in number to the number of the areas in
each group and being formed on the ribbon in alignment with
respective ones of the areas in each group.
Embodiments of the present invention will now be
described, by way of example, with reference to the
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accompanying drawings, throughout which like parts are
designated by like reference numerals, and in which:
Figure 1 is a perspective view of a thermal
transfer printer having a ribbon tensioning means in a
ribbon feed arrangement thereof;
Figure 2 is a schematic diagram illustratively
showing the construction of Figure l;
Figure 3 is a schematic diagram illustratively
showing the construction of a thermal transfer printer
having a ribbon tensioning means in a ribbon feed
arrangement thereof;
Figure 4 is a perspective Yiew of a portion of a
colored transfer ribbon and sensors of Figure 1 according to
one embodiment of the present invention;
Figure 5 is a perspective view of a trailing end
portion of the colored transfer ribbon of Figure 4; and
Figure 6 is a perspective view of the colored
transfer ribbon and sensors showing a modification thereof.
Referring now to the drawings, Figures 1 and 2
illustrate a thermal transfer type recording apparatus 1
having a ribbon tensioning means in a ribbon feed
arrangement thereof according to one preferred embodiment of
the present invention. The thermal transfer type recording
apparatus 1 of Figures 1 and 2 is provided in sequence with
a feed roller 12, a tension roller 13, a platen roller 14,
a thermal print head 15 and a take-up roller 16 from the
upstream side toward the downstream side thereof, with
respect to the direction of feed of a transfer medium, such
as a transfer ribbon 20, as shown by arrow b. Each of the
rollers 12, 13, 14 and 16 is freely rotatably disposed
between a pair of frames la of the apparatus 1. A plurality
of ribbon guides 17 is also disposed at proper positions in
the apparatus 1 for guiding the transf~r ribbon 20 fed from
the feed roller 12. Furthermore, as shown in Figure 2, a
pair of sheet press rollers 18 is so disposed as to be held
in pressure contact with the platen roller 14, for
transporting a recording sheet 21 between both of the sheet
press rollers 18 and the platen roller 14. In the thermal
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transfer type recording apparatus 1, the thermal print head
15 is disposed in face-to-face relation with the platen
roller 14, for heat transferring print from the transfer
ribbon 20 (heated by a line of heating elements 15a disposed
in the thermal print head 15) onto the recording sheet 21
for printing by an arrangement in which the transfer ribbon
20 is disposed upon the recording sheet 21 in pressure
contact with each other on the platen roller 14.
The transfer ribbon 20 is wound around the feed
roller 12, while a thermal melting type pigmented material
is spread on the transfer ribbon 20 on the surface thereof
facing the racording sheet 21. The transfer ribbon 20 is
roller around the take-up roller 16 which is, as a take-up
means, rotatably driven in the direction shown by arrow a by
a motor M or the like, synchronously with the feed speed of
the recording sheet 21 by way of the space between the
platen roller 14 and the thermal print head 15.
The recording sheet 21 is fed from another feed
roller (not shown) freely rotatably disposed on the upper
rear side of the apparatus 1 and is transfer-printed thereon
through the platen roller 14 and thereafter, the recording
sheet 21 is rolled round another take-up roller (not shown)
which is also freely rotatably mounted on the lower rear
side of the apparatus 1 and is driven by a motor or the
like.
In the ribbon feed arrangement of the transfer
type recording apparatus 1 having the above described
construction, the tension roller 13 disposed on the upstream
side of the apparatus 1 from which the transfer ribbon 20 is
supplied, is provided with a surface layer formed of an
elastic material such as rubber or the like having a high
friction coefficient, and a torque limiter T such as TRQ-LMT
(Trade Mark) is so disposed as to apply a predetermined load
to the tension roller 13, with the transfer ribbon 20 being
wound up under a constant tension around the take-up roller
16.
In order to wind up the transfer ribbon 20 under
a constant tension by the take-up roller 16, the number of
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revolutions and the rotational torque of the take-up roller
16 must be inversely proportional to each other.
Accordingly, the arrangement is so designed as to be capable
of winding up the transfer ribbon 20 under constant tension
by connecting the take-up roller 16, for example, to a
driving source (not shown) which selectively employs therein
a gear ratio by which a torque curve having a relationship
approximately similar to that of the aforementioned inverse
proportion can be obtained.
In this embodiment, although the torque limiter T
is employed for applying the constant load to the tension
roller 13, the device is not limited thereby and any loader
which can give the constant load may be replaced by the
torque limiter T.
The thermal transfer type recording apparatus 1
having the above described construction will be described
hereinafter.
The transfer ribbon 20 supplied from the feed
roller 12 is supplied under constant load by the tension
roller 13 connected to the torque limiter T, and is
simultaneously wound up by the take-up roller 16 under the
constant tension, thus resulting in the transfer ribbon 20
being desirably supplied in a manner in which it is under
constant tension at all times. The transfer ribbon 20
receiving the constant tension thereon is inserted, together
with the recording sheet 21, between the platen roller 14
and the thermal print head 15 through the ribbon guide 17,
and upon completion of the printing on the recording sheet
21 by the thermal print head 15, the transfer ribbon 20 is
rolled round the take-up roller 16 through the ribbon guides
17. In the above described manner, it is capable of not
only synchronizing the travel of the recording sheet 21 and
the transfer ribbon 20, but also stabilizing the tension
applied to the transfer ribbon 20.
Figure 3 schematically illustrates the thermal
transfer type recording apparatus 1 having a ribbon
tensioning means therein. In Figure 3, the ribbon feed
arrangement of the apparatus 1 having the ribbon tensioning
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means ther~in is so constructed that the tension roller 13
connected to the torque limiter T is held in direct contact
with the outer peripheral surface of the feed roller 12, and
the tension roller 13 is adequately pressed against the feed
roller 12 by a weight or the like so as to follow the non-
constant diameter of the feed roller 12. The construction
is, in other respects, the same as that of the ribbon feed
arrangement shown in Figures 1 and 2.
A color thermal transfer printer to which the
present invention is applied, will be explained hereinafter.
A colored transfer ribbon 20 and the recording
sheet 21 are held in pressure contact with each other
between the platen roller 14 and the thermal print head 15,
and colored ink of the colored transfer ribbon 20 heated by
the line of heating elements 15a is printed on the recording
sheet 21 by being heat-transferred thereon. Although the
recording sheet 21 is firstly transported by the platen
roller 14 and the pair of sheet press rollers 18 in the feed
direction of the recording sheet 21, it is further
transported in a direction opposite to the feed direction
thereof every time the transfer of one of the inked layers
is completed in the transfer for one page and, as a result,
the recording sheet 21 is caused to reciprocate by the
number of inked layers formed in a group thereof
corresponding to one page. On the other hand, the colored
transfer ribbon 20 supplied in turn from the feed roller 12
is guided by the ribbon guides 17 and is wound up around the
take-up roller 16 after completion of the transfer. An
optical detecting means S is disposed in position on the
feed side of the colored transfer ribbon 20 with respect to
the thermal print head 15, for detecting the color and the
transfer position of the colored transfer ribbon 20. The
optical detecting means S is not necessarily required to be
placed at the transfer position facing the line of heating
elements 15a, but may be arranged at any position where it
is easily placed, by adequately selecting the marking
positions of the colored transfer ribbon 20 in accordance
with the positional relationship between the line of heating
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elements 15a and the optical detecting means S, or by
electrically and adequately setting the feed length of the
colored transfer ribbon 20.
Figure 4 illustrates a portion of the colored
transfer ribbon 20 and the optical detecting means S, and
Figure 5 illustrates the trailing end portion of the colored
transfer ribbon 20 of Figure 4.
As shown in Figure 4, there are formed on the
colored transfer ribbon 20, color-inked layers 20a to 20d
having respectively the colors yellow, magenta, cyan and
black with respect to the feed direction of the ribbon 20 as
shown by arrow b so as to form successively a group of inked
layers corresponding to one page of the recording sheet 21.
The marking portions are formed at an edge portion on one
side of the colored transfer ribbon 20 in a lengthwise
direction thereof and not only positioning markers 21a to
21d are so marked on the ribbon 20 in alignment with the
respective color-inked layers 2Oa to 2Od in each group, but
also a cuing marker 22 is marked on the ribbon 20 in the
vicinity of the positioning marker 21a in alignment with the
yellow inked layer 20a positioned firstly in a group of
inked layers 20a to 20d. Each of the positioning markers
21a to 21d is so formed as to face the first sensor Sa, when
the leading end portion of respective inked layers 20a to
20d reaches the transfer position facing the line of heating
elements 15a. Each of the first and second sensors Sa and Sb
forming the optical detecting means S is composed of a
photosensor comprising a light emitting diode and a
phototransistor disposed on respective surfaces of the
ribbon 20 so as to face each other. The sensors Sa and Sb
are both so positioned that the distance therebetween
coincides with that between the positioning mar~er 21a and
the cuing marker 22 corresponding to the first yellow inked
layer 20a.
In the case of transfer onto the recording sheet
21, when the colored transfer ribbon 20 is brought to a halt
at the time when both of the markers 21a and 22 are
simultaneously detected by both of the sensors Sa and Sb,
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the leading end portion of the yellow inked layer 20a
positioned firstly in the group of inked layers 20a to 20d
faces the line of heating elements 15a. Thereafter, the
recording sheet 21 is supplied by a certain constant pitch,
while the line of heating elements 15a is heated in
accordance with print signals, and the yellow ink of the
yellow inked layer 2Oa melted thereby is transferred onto
the recording sheet 21 and upon completion of the transfer
of the yellow ink for the corresponding page, the recording
sheet 21 is conversely transported to the original position,
while the colored transfer ribbon 20 is caused to run idle.
Thereafte~, when the positioning marker 21b correspcnding to
the second magenta inked layer 20b is detected by the first
sensor Sa, the ribbon 20 is brought to a halt and the
magenta ink is transferred onto the recording sheet 21~ In
the same manner as described above, when the cyan ink and
the black ink are sequentially transferred onto the
recording sheet 21, the transfer for one page is completed
and the ribbon 20 is fed further.
During the printing operation described above,
since all of the inked layers 20a to 20d are sequentially
formed in the predetermined order, the color of each layer
is judged by the number of the positioning markers 21a to
21d to be detected which have been counted by the first
sensor Sa. Accordingly, for example, when a print signal
for the cyan ink is not outputted, the colored transfer
ribbon 20 is not brought to a halt, but continues to be
transported at the time the third positioning markers 21c is
detected and, thereafter, the color-inked ribbon 20 is
brought to a halt at the time the fourth positioning marker
21d is detected.
At the trailing end portion of the colored
transfer ribbon 20, there are formed as many end markers 23a
to 23d as the four inked layers 20a to 20d composing one
group of inked layers, next to the last black inked layer
20d, and the distance between adjacent end markers 23a to
23d is determined to be longer than that between both
sensors Sa and Sb and to be shorter than that between
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adjacent positioning markers 21a to 21d. Accordingly, since
the black inked layer 20d is followed by the yellow inked
layer 20a at the portions other than the trailing end
portion of the ribbon 20, the markers 21a and 22 are
detected simultaneously by both the sensors Sa and Sb at the
aforementioned portions. Notwithstanding this fact, when
both the sensors sa and Sb are not simultaneously turned on,
it is judged that the trailing end portion of the colored
transfer ribbon 20 has been detected. Thereupon, if only
one end marker is formed next to the black inked layer 20d
and the detection of the trailing end portion of the ribbon
20 is judged by detecting one end marker after the black
inked layer 20d has been detected, any such possible
erroneous operation as judging the detection of the trailing
end portion of the ribbon 20 may undesirably take place in
the case where either one of the markers 21a and 22 of the
yellow inked layer 20a has been detected only in the
intermediate portion of the ribbon 20 for some reason or
other. In order to avoid the aforementioned drawback, four
end markers 23a to 23d are formed at the trailing end
portion of the colored transfer ribbon 20.
A detecting means as shown in Figure 6 may be
employed for detecting the trailing end portion of the
colored transfer ribbon 20. More specifically, there may be
disposed an additional third sensor Sc in the vicinity of
the first and second sensors Sa and Sb, and three end
markers may be formed in a manner such that the distance
between adjacent markers is caused to coincide with that
between adjacent sensors Sa to Sc at the trailing end
portion of the colored transfer ribbon 20. In such manner,
since all three of the sensors Sa to Sc are simultaneously
turned on only when three end markers have been
simultaneously detected or when the colored transfer ribbon
20 has not been set, a state where the colored transfer
ribbon 20 is not set can be also detected and, as a result,
the operation of the printer can be avoided in the
aforementioned state. However, this method has been found
disadvantageous in that a new ribbon must be set in a manner
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such that the leading tape portion thereof is not left at
the position where each of the sensors faces the ribbon,
since all of the sensors are erroneously turned on, when the
leading tape portion of the ribbon faces each of the sensors
Sa to Sc in the case where a used ribbon is replaced by a
new one. Accordingly, provided that a marking is formed on
the leading tape portion of the ribbon, the aforementioned
disadvantage can be preferably eliminated and, in addition,
not only can any possible slackening or damage of the ribbon
be effectively avoided, but also the ribbon can be easily
handled by forming the leading tape portion in a thickness
of approximately 20 m in order to cause it to be thicker
than the ribbon.
In the above described embodiment of the colored
transfer ribbon, each of the markers 21a to 21d, 22 and 23a
to 23d is formed on the ribbon in a light transmitting mode.
In contrast, if each of them is formed in a light screening
mode, since a black ink is spread only on the portions where
each of the markers 21a to 21d, 22 and 23a to 23d is formed,
there arises the drawback that the colored transfer ribbon
20 is loosely wound up in a rolled state due to an increased
amount of ink only in the marked portions. When each of the
markers 21a to 21d, 22 and 23a to 23d is formed in the light
transmitting mode as described above, the black ink is
spread on a great part of the edge portion of the colored
transfer ribbon 20 other than the markers 21a to 21d, 22 and
23a to 23d and this has been found to be particularly
effective from the viewpoint of the handling or travelling
of the ribbon 20, since any wrinkling thereof can be
substantially eliminated due to the fact that the amount of
ink spread on the edge portion of the ribbon 20 is
approximately as same as that spread on the inked layers 2Oa
to 20d.
In all examples of the colored transfer ribbon
described so far, the distance between adjacent markers
should be kept unchangeable for the purpose of proper
detection thereof by the optical detecting means and it is
capable of achieving such state by maintaining the tension
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12
applied on the colored transfer ribbon substantially
constant by means of the aforementioned ribbon feed
arrangement disposed in the color thermal transfer printer.
Furthermore, each inked layer of the colored
5 trans~er ribbon can be properly transferred onto the
recording sheet in position without any deviation between
printed colors thereon due to the fact that any possible
slackening or wrinkling of the colored transfer ribbon can
be completely prevented by the ribbon feed arrangement in
10 the color thermal transfer printer.
With respect to the markers formed on the colored
transfer ribbon, since the portions to be marked are
3 disposed only on one side of the colored transfer ribbon at
the edge portion thereof, the space required for marking has
15 been advantageously reduced, as compared with any
conventional case, and accordingly, each of the inked layers
can be effectively formed on the colored transfer ribbon.
Moreover, since it has been found satisfactory to form one
marker on each of the inked layers other than the first one
20 in each group of inked layers, the markers can be extremely
simply formed on the colored trans~er ribbon, thus resulting
in the ready detection thereof. In addition to this, the
sensors for detecting the markers can be reduced both in
number and in cost. Also, in case of detection of the
25 markers, since the inked layers are excluded from the region
to be detected, the sensors can be advantageously kept in a
; high sensitive state at all times.
Although the present invention has been fully
described by way of example with reference to the
30 accompanying drawings, it should be noted that various
changes and modifications may be made which will be apparent
to those skilled in the art. Therefore, unless such changes
and modifications otherwise depart from the scope of the
present invention, they should be construed as being
35 included therein.
