JPH09267500A - Color thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a color print with extremely least margins. SOLUTION: Couples of upstream carrying rollers 25-27 for carrying color heat-sensitive recording papers 10 are disposed near respective thermal heads 15-17. When a first paper is heat recorded, heat recording is carried out to the end while a first recording area of the color heat-sensitive recording paper 10 is returned to the upstream side to respective thermal heads 15-17 so as to form no margin at the end. The interval between adjacent images is formed to be equal to two lines of the heat recording by the thermal heads, and the color heat-sensitive recording paper 10 is cut on the center of the margin equal to two lines.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color thermal printer, and more particularly to a color thermal printer for producing a color print with an extremely small margin.

[0002]

2. Description of the Related Art Color thermal printers are classified into a thermal recording type and a thermal transfer type, and both types use a thermal head in which a large number of heating elements are arranged in a line. The thermosensitive recording type uses color thermosensitive recording paper in which at least a yellow thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a cyan thermosensitive coloring layer are sequentially layered from the outside on a support, and a thermal head is used in order from the outside thermosensitive coloring layer. By performing thermal recording, a full color print can be obtained. The thermal transfer type uses a color ink sheet in which at least three color ink areas of yellow, magenta, and cyan are alternately formed, and a full-color print is obtained by thermally transferring the ink of each ink area to recording paper.

[0003] Such a color thermal printer includes:
A three-pass method in which recording paper is passed three times through one thermal head to perform thermal printing, and a one-pass method in which recording paper is passed once through a plurality of thermal heads to perform thermal printing (particularly, No. 6-96338). This one-pass type color thermal printer requires the same number of thermal heads as the number of colors to be thermally recorded. Therefore, the price of the printer itself increases as compared with the three-pass type, but the printing time is shortened, so that a large number of sheets Is used for a commercial color thermal printer or the like that continuously prints images.

FIG. 11 shows an outline of a yellow thermal head portion of a thermal recording type one-pass color thermal printer. In this color thermal printer, a long color thermosensitive recording paper 2 wound in a roll shape is used.
Is conveyed by being sandwiched by a conveying roller pair 6 composed of a capstan 4 and a pinch roller 5 which are arranged on the downstream side in the vicinity of the yellow thermal head 3. Then, during this conveyance, the color thermal recording paper 2 is sandwiched by the yellow thermal head 3 and the platen roller 7, the heating element array 3a is appropriately heated, and thermal recording is performed in the recording area.

Further, after the recorded thermosensitive coloring layer is optically fixed by the fixing device 8 for yellow arranged on the downstream side of the conveying roller pair 6, the thermal head for magenta and the one for magenta arranged on the further downstream side. Thermal recording and fixing are performed with a fixing device and a cyan thermal head (not shown). As described above, the thermal recording paper 2 is conveyed in one direction, thermally recorded by each thermal head, a plurality of full color images are printed, and the full color images are cut to form a large number of color prints. There is.

[0006]

Generally, when a plurality of images are continuously recorded, a blank space is formed around each image as a white line. The margins at both edges can be reduced by lengthening the thermal head, and the margins between images can be eliminated by adjusting the drive start timing of each thermal head.

However, since the margin 9 between the leading edge of the recording paper and the first image is generated by the distance L between the thermal head 3 and the conveying roller pair 6, this margin at the leading edge is a waste of the recording paper. Becomes Further, since the margin 9 gives the impression that the image is recorded on the recording paper with an offset, it is necessary to cut it off with a cutter.

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and an object of the present invention is to provide a color thermal printer capable of producing a color print with an extremely small margin without cutting the color thermosensitive recording paper. To do.

[0009]

In order to solve the above problems, the color thermal printer according to claim 1 conveys the recording paper to the upstream side in the vicinity of each thermal head, with the recording paper sandwiched therebetween. When each upstream transport roller pair is arranged and the first full-color image is thermally recorded on the recording paper, each upstream transport roller pair returns the recording paper toward the upstream side, and each thermal head prints the recording paper. The image is thermally recorded toward the leading edge of the sheet, and the second and subsequent full-color images are recorded from the downstream side to the upstream side of the recording sheet while the downstream conveying roller pair conveys the recording sheet toward the downstream side. It was made to record heat. According to this, it is possible to eliminate the blank space existing at the front end of the recording paper without cutting the recording paper.

Further, in the color thermal printer according to the second aspect of the invention, as the recording paper, a color thermal recording paper in which thermosensitive coloring layers of at least three colors having different thermal sensitivities are laminated is used, and thermal recording is completed between each thermal head. Fixing lamps for optically fixing the thermosensitive coloring layer are arranged on the upstream side of these fixing lamps when the first full-color image is recorded on the color thermosensitive recording paper and optically fixed. A light-shielding plate is arranged to prevent the recording portion from being fixed.

Further, in the color thermal printer according to the third aspect of the invention, the interval between the plurality of full-color images thermally recorded on the recording paper is two lines of thermal recording by the thermal head,
By cutting the recording paper in the middle of the margins of these two lines, it is possible to create a color print with extremely small margins.

[0012]

1 is a schematic view of a linear movement type color thermal printer embodying the present invention. In this printer, a long color thermosensitive recording paper 10 wound in a roll is used as a recording paper, and a paper feed roller pair 21 is used.
Pulled out of the roll by. When the number of frames recorded at one time is extracted, the cutter 14 cuts the rear end.

Three platen rollers 11, 12 and 13 are arranged at appropriate intervals along the pass area of the intercolor thermal recording paper 10. Each platen roller 11-13
, A yellow thermal head 15, a magenta thermal head 16, and a cyan thermal head 17 are arranged so as to face each other. With these, the yellow print stage 18 and the magenta print stage 1 are arranged along the path.
9. The cyan print stage 20 is formed.

In the vicinity of the platen rollers 11 to 13, the color thermosensitive recording paper 10 is conveyed downstream toward the downstream side (left side in the drawing) and the upstream side in the conveying direction of the color thermosensitive recording paper 10. Transport roller pairs 22, 23, 24 and upstream transport roller pairs 25, 26, 27 for transporting upstream.
And are respectively arranged.

Each pair of conveying rollers 22 to 27 is arranged below the color thermosensitive recording paper 10 and has pulse motors 29 and 3.
It is composed of a capstan driven by 0, 31 and a pinch roller arranged above the color thermosensitive recording paper 10 and pressed against the capstan by a cam or solenoid. The transport roller pairs 22 to 27 sandwich the color thermosensitive recording paper 10 by pressing the pinch rollers, and transport the color thermosensitive recording paper 10 toward the downstream side or the upstream side by the rotation of each capstan.

The upstream conveying roller pair 25 to 27 transfers the color thermosensitive recording paper 10 to the thermal heads 15 to 17 on the upstream side when thermally recording a full-color image on the first recording area on the front side. Used to transport to.
The downstream transport roller pairs 22 to 24 are used as a pre-stage for the upstream transport roller pairs 25 to 27 to transport the color thermosensitive recording paper 10 toward the upstream side.
Of the color thermosensitive recording paper 10 to the downstream side in order to thermally record a full-color image in the second to nth recording areas behind the first recording area. Used when

Mark sensors 33, 34 and 35 are arranged in the vicinity of the platen rollers 11 to 13 on the upstream side in the transport direction of the color thermosensitive recording paper 10. Mark sensor 3
Reference numerals 3 to 35 are reflection type sensors having a light projecting portion and a light receiving portion, and detect the leading end of the color thermosensitive recording paper 10 and the marks 36 formed on the color thermosensitive recording paper 10 at regular intervals. In this embodiment, the mark 36 is a C0.5 notch (see FIG. 1) formed on one side edge of the color thermosensitive recording paper 10.
However, it may be provided on the back surface by printing at the time of manufacturing the color thermal recording paper 10, or immediately after being set in the printer and pulled out from the roll, it is predetermined by a mark printer, a pinhole forming device or the like. You may form at intervals.

The space between the marks 36 is the color print 52.
The mark 36 indicates the recording area and the cutting position of the color thermosensitive recording paper 10. Therefore, the mark sensor 33 to 35 is used to mark the mark 3.
By counting the motor drive pulses of the pulse motors 29 to 31 from the time point 6 is detected, the color thermosensitive recording paper 10 is tracked to specify the recording start position of each recording area, and the thermal heads 15 to 17 are also specified.
The timing of pressure contact and separation of the pinch roller and the color thermosensitive recording paper 10 is obtained.

The thermal heads 15 to 17 have a heating element array 15a in which a large number of heating elements are arranged in a line,
16a and 17a are provided. These heating element arrays 15a to 17a extend in the axial direction of the platen rollers 11 to 13 and are wider than the width of the color thermosensitive recording paper 10. Then, the color thermosensitive recording paper 10 is sandwiched by being pressed against the platen rollers 11 to 13 at a specific timing by a cam, a solenoid or the like, and the heating element arrays 15a to 17a are caused to generate heat at a predetermined temperature, and each thermosensitive coloring layer has each color. Thermal recording of images.

The size of the image thermally recorded in each recording area defined by the mark 36 is slightly smaller in the entire circumference than in the recording area, and as shown in FIG. The margins L1 formed on the leading and trailing ends of the sheet are one line (about 0.1 mm) of the thermal recording of the thermal head with respect to the mark 36, and are sub-scanned in the direction of conveyance of the color thermal recording paper 10. The margin L2 in the direction is 0.1 mm with respect to both side edges of the color thermosensitive recording paper 10. That is, in the finally produced color print 52, a margin of 0.1 mm is formed on the entire circumference of the image, but this margin seems to be an edge of the color print in appearance, and therefore, at first glance. Then, a color print with no margin can be created.

When the color thermal recording paper of plural kinds of widths can be set in the color thermal printer, the width of the set color thermal recording paper is detected by the sensor and the width is adjusted to this width. The recording area can be set automatically.

A yellow fixing device 38 and a magenta fixing device 39 are arranged between the thermal heads 15 to 17. These fixing devices 38 and 39 are composed of ultraviolet lamps 38a and 39a and reflectors 38b and 39b, and the yellow fixing device 38 has an emission peak of 42.
The near-ultraviolet ray of 0 nm is emitted, and the magenta fixing device 39 emits the near-ultraviolet ray having an emission peak of 365 nm. The yellow fixing device 38 and the magenta fixing device 39 respectively fix the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer of the color thermosensitive recording paper 10 so as not to develop color even when heated.

Further, on the upstream side of each fixing device 38, 39,
In order to prevent the ultraviolet rays emitted from the ultraviolet lamps 38a, 39a from leaking to the upstream side of the color thermosensitive recording paper 10, UV filters 40, 41 are arranged as light shielding plates. With the conventional 1-pass color thermal printer,
Since the color thermosensitive recording paper was moved in only one direction to thermally record a plurality of images continuously, when the first recording area reaches the fixing device, the images are already recorded in the second recording area. Therefore, there was no problem even if the ultraviolet rays reached the second recording area.

However, in the color thermal printer of the present invention, when fixing the first recording area, the second recording area
Since no image has been recorded in the recording area yet, there is a problem that the ultraviolet rays are fixed when they reach the second recording area, and the image cannot be thermally recorded. The UV filters 40 and 41 prevent the second recording area from being fixed when the first recording area is fixed.

On the downstream side of the cyan print stage 20, the color thermosensitive recording paper 10 having been printed is cut at a predetermined interval to form a plurality of color prints 52, and the color prints 52 are discharged to the outside of the printer. And a pair of paper discharge rollers 44 are arranged. The cutting device 43
The color thermosensitive recording paper 10 is composed of a pair of cutting blades that sandwich the color thermosensitive recording paper 10 at the top and bottom, and cut the color thermosensitive recording paper 10 at the position of the mark 36. Further, a mark sensor 45 for specifying the cutting position is arranged on the upstream side of the cutting device 43. Although not shown, the color thermal printer includes a control unit including a CPU for controlling each unit and an operation unit.

FIG. 2 shows an example of the layer structure of the color thermosensitive recording paper 10. The color thermosensitive recording paper 10 includes a support 47 such as an opaque coated paper or a plastic film.
On top of it, cyan thermosensitive coloring layer 48, magenta thermosensitive coloring layer 4
9, a yellow thermosensitive coloring layer 50, and a protective layer 51 are sequentially stacked. Each of the thermosensitive coloring layers 48 to 50 has a thermal sensitivity according to the distance from the surface thereof, and the yellow thermosensitive coloring layer 50.
Has the highest thermal sensitivity, and the cyan thermosensitive coloring layer 48 has the lowest thermal sensitivity.

The yellow thermosensitive coloring layer 50 is fixed to the yellow fixing device 38 and the magenta thermosensitive coloring layer 49 is fixed to the magenta fixing device 39, but the cyan thermosensitive coloring layer 4 is fixed.
Since No. 8 has a thermal sensitivity that does not develop color in a normal storage state, no fixing property is imparted. The thermosensitive coloring layers 48 to 50 are layered from the surface in the order in which thermal recording is performed. For example, when thermal recording is performed in the order of magenta, yellow, and cyan, the position of each thermosensitive coloring layer is Can be replaced. Although not shown in the drawing, each thermosensitive coloring layer 4
An intermediate layer for adjusting thermal sensitivity is provided between 8 and 50.

Next, the operation of the above embodiment will be described with reference to FIG.
This will be described according to the flowchart shown in FIG. In FIG. 3, yellow, magenta, and cyan are indicated by their initials Y, M, and C, respectively. When a print start operation is performed, the color thermosensitive recording paper 10 is conveyed toward the platen roller 11 (downstream side) by the paper feed roller pair 21 shown in FIG. At this point, each thermal head 15-17
Also, the pinch rollers of each of the pair of conveying rollers 22 to 27 are lifted with respect to the platen rollers 11 to 13 and the capstan to secure the passage of the color thermosensitive recording paper 10.

While the color thermosensitive recording paper 10 is being conveyed by the paper feed roller pair 21, the leading edge of the color thermosensitive recording paper 10 is detected by the mark sensor 33, and from this detection, the paper feed roller pair 2 is detected.
The motor drive pulse of the pulse motor that drives 1 is counted by the control unit. Then, when the motor drive pulse reaches a predetermined count number, the pinch roller of the downstream conveying roller pair 22 descends to nip the color thermosensitive recording paper 10.

The downstream conveying roller pair 22 conveys the color thermosensitive recording paper 10 to the downstream side together with the paper feeding roller pair 21 by the rotation of the capstan by the pulse motor 29. During this conveyance, the first mark 36 of the color thermosensitive recording paper 10 is detected by the mark sensor 33, and the motor drive pulse of the pulse motor 29 is counted by the control unit from this detection. Then, when the motor drive pulse reaches a predetermined count number, the downstream conveyance roller pair 22 and the paper feed roller pair 21
And are stopped. When the color thermosensitive recording paper 10 is stopped, the mark 36 is at a position facing the yellow thermal head 15, and the first recording area on which the first full-color image is thermally recorded on the color thermosensitive recording paper 10 is It is arranged on the downstream side of the yellow thermal head 15.

Next, the yellow thermal head 15
Then, the pinch roller of the upstream transport roller pair 25 is lowered and pressed against the color thermosensitive recording paper 10, and the nip state between the downstream transport roller pair 22 and the paper feed roller pair 21 is released. Further, the capstan of the upstream conveying roller pair 25 is driven by the pulse motor 29, and the color thermosensitive recording paper 1
0 is transported toward the upstream side. During this return, the heater element array 15a of the yellow thermal head 15 is energized with a blank space for one line from the mark 36, and the yellow image (see FIG. 4) is formed on the yellow thermosensitive coloring layer 50 in the first recording area. The upward-sloping diagonal line) is thermally recorded.

Further, during the thermal recording of the yellow image on the first recording area, the mark sensor 33 re-marks the mark 3 again.
6 is detected, and the upstream conveyance roller pair 25 is stopped when the count of the predetermined motor drive pulse is completed. When the upstream transport roller pair 25 is stopped, as shown in FIG. 4, the front end of the color thermosensitive recording paper 10 faces the yellow thermal head 15, and the color thermosensitive recording paper 10 has the first recording area. 25 pairs of upstream transport rollers
It means that it was transported upstream.

When the upstream conveying roller pair 25 is stopped,
The paper feed roller pair 21 nips the color thermosensitive recording paper 10,
The yellow thermal head 15 is raised, and the nip formed by the upstream transport roller pair 25 is released. Then, the paper feed roller pair 21 and the downstream conveyance roller pair 22 convey the color thermosensitive recording paper 10 again toward the downstream side. And
During the conveyance to the downstream side, the ultraviolet lamp 38a of the yellow fixing device 38 is turned on, and the yellow thermosensitive coloring layer 50 in the first recording area is optically fixed, as shown in FIG. Since the UV filter 40 is arranged on the upstream side of the yellow fixing device 38, the second recording area is not fixed carelessly.

During fixing by the yellow fixing device 38, the leading edge of the color thermosensitive recording paper 10 is detected by the mark sensor 34, and after a predetermined motor drive pulse is counted, the pinch roller of the downstream conveying roller pair 23 descends. The color thermosensitive recording paper 10 is nipped, and the color thermosensitive recording paper 10 is further conveyed to the downstream side together with the paper feed roller pair 21 and the downstream conveying roller pair 22. After a predetermined motor drive pulse after the mark sensor 34 detects the mark 36, the downstream conveying roller pair 22 and 23 and the paper feed roller pair 21 are stopped. At this stop, the mark 36 faces the magenta thermal head 16 as shown in FIG. 6, and the first recording area is arranged on the downstream side of the magenta thermal head 16.

When the color thermosensitive recording paper 10 is stopped, the magenta thermal head 16 and the upstream conveying roller pair 2 are used.
The pinch rollers 5 and 26 are pressed against the color thermosensitive recording paper 10, and then the nip state between the downstream conveying roller pair 22 and 23 and the paper feeding roller pair 21 is released. Further, the capstan of the upstream conveying roller pair 25, 26 is the pulse motor 2
The color thermosensitive recording paper 10 is driven by 9 and 30 and is conveyed toward the upstream side. During this return, the heating element array 16a of the magenta thermal head 16 is energized, and the magenta image (the downward-sloping diagonal line shown in FIG. 7) is thermally recorded on the magenta thermosensitive coloring layer 49 in the first recording area.

Further, during the thermal recording of the magenta image in the first recording area, the mark sensor 33 marks the mark 3 again.
6 is detected, and the upstream conveyance roller pair 25, 26 is stopped when the count of the predetermined motor drive pulse is completed. At this time, as shown in FIG. 7, the front end of the color thermosensitive recording paper 10 is at a position facing the yellow thermal head 16.

When the nip state of the color thermosensitive recording paper 10 is released by the upstream transport roller pair 25, 26 and the magenta thermal head 16 is raised, the paper feed roller pair 21 and the downstream transport roller pair 22 are again provided. , 23 convey the color thermosensitive recording paper 10 toward the downstream side. Then, during the conveyance to the downstream, the ultraviolet lamp 39a of the magenta fixing device 39 is turned on, and the magenta thermosensitive coloring layer 49 in the first recording area is optically fixed. At the time of this fixing, the UV filter 41 prevents ultraviolet rays from leaking to the upstream side, so that the second recording area is not fixed carelessly.

During fixing by the magenta fixing device 39, the front end of the color thermosensitive recording paper 10 is detected by the mark sensor 35, and after a predetermined motor drive pulse is counted, the pinch roller of the downstream conveying roller pair 24 descends, The color thermosensitive recording paper 10 is further transported to the downstream side together with the paper feed roller pair 21 and the downstream transport roller pairs 22 and 23. Then, after the mark sensor 35 detects the mark 36, and after a predetermined motor drive pulse, the downstream conveying roller pair 22, 23, 2
4 and the paper feed roller 21 are stopped. Mark 3 at this time
6 is a cyan thermal head 17 as shown in FIG.
Oppose.

The cyan thermal head 17 and the pinch rollers of the upstream conveying roller pairs 25, 26, 27 are pressed against the color thermosensitive recording paper 10, and then the downstream conveying roller pairs 22, 23, 24 and the paper feeding roller pair. The nip state with 21 is released. The capstan of the upstream transport roller pair 25, 26, 27 is driven to transport the color thermosensitive recording paper 10 toward the upstream side. During this return, the heating element array 17a of the cyan thermal head 17 is energized,
A cyan image (horizontal line shown in FIG. 9) is thermally recorded on the cyan thermosensitive coloring layer 48 in the second recording area.

When the thermal recording of the cyan image by the cyan thermal head 17 is completed, the cyan thermal head 1
7, the upstream conveying roller pairs 25 to 27 return the color thermosensitive recording paper 10 to the position where the mark 36 faces the yellow thermal head 15 and stop, as shown in FIG. Then, after the downstream transport roller pair 22, the paper feed roller pair 21, and the yellow thermal head 15 are pressed against the color thermal recording paper 10, the nip state of the downstream transport roller pairs 25 to 27 is released.

The downstream conveying roller pair 22 conveys the color thermosensitive recording paper 10 toward the downstream side, and the yellow thermal head 15 leaves a margin for one line from the mark 36 and makes the yellow recording area yellow. Record the image. As a result, as shown in FIG. 10, a blank space of about 0.2 mm for two lines is formed between the first full-color image and the second full-color image. After that, the downstream conveying roller pairs 22 to 24 convey the color thermosensitive recording paper 10 to the downstream side, and the thermal heads 15 to 17 are pressed against the color thermosensitive recording paper 10 at any time so that the second and subsequent recording areas are recorded. Record multiple full-color images in succession.

In the second and subsequent images, the thermal heads 15 to 17 are in contact with the color thermosensitive recording paper 10 under pressure.
Each image is heat-recorded on each thermosensitive coloring layer 48-50. When the color thermosensitive recording paper 10 is supplied from the paper feed roller pair 21 for the required number of recording areas during printing, the cutter 14 operates to cut the color thermosensitive recording paper 10 and the paper feed roller pair 21 stops. .

In this way, a full-color image is recorded at a line pitch in each recording area of the color thermosensitive recording paper 10 by the three-color frame sequence. And the color thermosensitive recording paper 1
When the leading edge of 0 is detected by the mark sensor 45, after a predetermined number of motor driving pulses, the cutting device 43 causes the mark 3
At the position 6, the color thermosensitive recording paper 10 is cut. The color print 52 that has been cut and separated from the color thermosensitive recording paper 10 is ejected outside the printer by the paper ejection roller pair 44. This results in about 0.1 around the full-color image.
Color print with a very small margin of 5 mm
2 is created. Even in the thermal recording of the second and subsequent sheets, a margin for two lines is formed with respect to the immediately preceding color image, and the color thermosensitive recording paper 10 is cut in the middle, so that a similar color print with a small margin can be performed. can get.

Further, after the yellow image is thermally recorded in the first recording area, the yellow image is thermally recorded and fixed in the second recording area while being conveyed to the magenta print stage 19. After thermally recording the magenta image in the recording area of No. 1 and while being conveyed to the cyan print stage 20, the magenta image and the yellow image are thermally recorded and fixed in the second and third recording areas, respectively.
After that, a cyan image may be thermally recorded in the first recording area. According to this, after the full-color image is thermally recorded in the first recording area, the color thermal recording paper 10 is
The third recording area can be set on the magenta print stage for subsequent printing, and the printing time can be greatly reduced.

Although the above embodiment has been described with respect to the color thermal printer, the present invention can also be applied to a sublimation type or heat melting type thermal transfer printer using color ink sheets of yellow, magenta and cyan. In the case of this thermal transfer printer, a shading plate such as a UV filter is not necessary.

Further, since it is not necessary to perform thermal recording sequentially from the thermal head on the upstream side as in the color thermal printer, the thermal recording on the first recording area of the recording paper is performed on the most downstream side at the time of thermal recording of the first sheet. While returning from the head to the thermal head on the most upstream side, three colors can be thermally recorded in order, and after the second sheet, thermal recording can be performed while conveying the recording paper toward the downstream side.

Further, in addition to the color thermal printer which conveys the recording paper on a straight line, the recording paper may be conveyed along an arcuate path. Further, the pressure contact and separation of each thermal head to the recording paper changes the conveyance load of the recording paper to cause image misalignment between the respective colors, so by bending the recording paper between the thermal heads, It is better to absorb the transport load when the thermal heads are pressed and separated from each other by this bending.

[0048]

As described above, the color thermal printer of the present invention is provided with a roller pair for upstream conveyance in addition to the conventional roller pair for downstream conveyance, and heats the first full-color image on the recording paper. At the time of recording, the recording paper is conveyed to the upstream side with respect to each thermal head, and thermal recording is performed up to the leading edge.
Since the recording paper is conveyed to the downstream side for thermal recording after the first sheet, it is possible to eliminate the margin due to the downstream conveyance roller pair generated at the front end of the recording paper in the conventional printer,
The recording paper can be used without waste.

Further, when a color thermosensitive recording paper is used as the recording paper, the light-shielding plate is arranged on the upstream side of the fixing device, so that when the first full-color image is fixed, the second and subsequent ones are not yet fixed. The problem that the recorded part is fixed does not occur.

Further, the interval between the plurality of full-color images thermally recorded on the recording paper is set to two lines of thermal recording by the thermal head, and the recording paper is cut at the middle of the margin of these two lines. It is possible to create a color print with an extremely small margin.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a color thermal printer embodying the present invention.

FIG. 2 is an explanatory diagram showing an example of a layer structure of a color thermosensitive recording paper.

FIG. 3 is a flowchart showing an operation sequence of a color thermal printer embodying the present invention.

FIG. 4 is a schematic diagram showing a state of the color thermal printer at the end of thermal recording of a yellow image.

FIG. 5 is a schematic view showing a state of the color thermal printer at the time of fixing the yellow thermosensitive coloring layer.

FIG. 6 is a schematic view showing a state of the color thermal printer before thermal recording of magenta image.

FIG. 7 is a schematic view showing the state of the color thermal printer at the end of thermal recording of magenta image.

FIG. 8 is a schematic diagram showing a state of a color thermal printer before thermal recording of a cyan image.

FIG. 9 is a schematic diagram showing a state of the color thermal printer before thermal recording in the second recording area.

FIG. 10 is an explanatory diagram showing a state between a first recording area and a second recording area.

FIG. 11 is a schematic diagram showing a configuration of a yellow print stage of a conventional color thermal printer.

[Explanation of symbols]

 10 color thermal recording paper 11-13 platen roller 15-17 thermal head 18-20 print stage 22-24 downstream transport roller pair 25-27 upstream transport roller pair 29-31 pulse motor 33-35, 45 mark sensor 36 mark 38, 39 Fixing device 40, 41 UV filter

Claims (3)

[Claims] 1. At least a plurality of thermal heads for thermally recording yellow, magenta, and cyan images on the recording paper one line at a time and a plurality of platens facing the thermal heads along a passage area of the recording paper. And a downstream transport roller pair that sandwiches the recording paper and transports it toward the downstream side in the vicinity of each thermal head, and each thermal head is pressed against the recording paper while the recording paper is being transported. In the color thermal printer, in which a plurality of full-color images are continuously heat-recorded and the adjacent full-color images are cut to form a plurality of color prints, recording paper is provided on the upstream side in the vicinity of each thermal head. A pair of upstream transport rollers, which are sandwiched and transported toward the upstream side, are arranged respectively, and when thermally recording the first full-color image on the recording paper, An image is thermally recorded toward the leading edge of the recording paper by each thermal head while returning the recording paper to the upstream side by the pair of conveying rollers, and the second and subsequent full-color images are recorded by the pair of downstream conveying rollers. The color thermal printer is characterized in that an image is thermally recorded from the downstream side of the recording paper to the upstream side while being conveyed toward the downstream side. 2. The recording paper is a color thermosensitive recording paper in which thermosensitive coloring layers of at least three colors having different thermal sensitivities are laminated,
A fixing device for optically fixing the thermosensitive color-developing layer that has been thermally recorded is arranged between the thermal heads, and the first full-color image is thermally recorded on the color thermosensitive recording paper on the upstream side of these fixing devices. 2. A light-shielding plate is arranged to prevent the unrecorded portion from being fixed when the light is fixed by light.
The described color thermal printer. 3. An interval between a plurality of full-color images thermally recorded on the recording paper is equal to two lines of thermal recording by a thermal head. The color thermal printer according to claim 2, wherein the color print is produced.