JPH1067128A - Color thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color thermal printer devised so as to eliminate waste of color thermal recording paper. SOLUTION: Yellow, magenta and cyan thermal heads 21, 22, 23 are successively arranged along a feed passage of color thermal recording paper 15 from an upstream side and a full-color image is recorded in a surface sequence manner by one feed of the color thermal recording paper 15. Fixing devices 37, 38 optically fix yellow and magenta thermal color forming layers after yellow and magenta images are recorded. Shutter mechanisms 70, 71 are provided to the fixing devices 37, 38 and each of them is provided with a shutter curtain 74 cutting off ultraviolet rays and a shutter feed roller pair 78 nipping the curtain to move the same. Each shutter curtain is nipped between nip rollers to be moved along with the color thermal recording paper to cut off light so that the unrecorded part on the rear end side of an image recording area is not fixed.

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 which uses color thermal recording paper in the form of a roll and separates the sheet after recording an image, and more particularly, to a shutter mechanism for preventing an unrecorded portion from being irradiated with ultraviolet rays. The present invention relates to a color thermal printer provided with a printer.

[0002]

2. Description of the Related Art A thermal recording type printer uses a color thermal recording paper in which at least a yellow thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a cyan thermosensitive coloring layer are sequentially formed on the support from the outside. By performing thermal recording in order from the outer thermosensitive coloring layer, a full-color print is created.

In such a color thermal printer, a one-head three-pass system in which a thermal recording paper is passed three times through one thermal head to perform thermal recording, or a color thermal printer in three thermal heads is used. Three-head one-pass system in which thermal recording paper is passed once to perform thermal recording (Japanese Patent Publication No. 6-963)
No. 38).

[0004] Color thermal printers are classified into a sheet type using color thermal recording paper in sheet form and a type using color thermal recording paper wound in a roll.

For example, in a three-head one-pass type color thermal printer, a thermal head for yellow, a thermal head for magenta, and a thermal head for cyan are sequentially arranged between a roll of thermal color recording paper and a discharge port on the downstream side. Have been. A yellow fixing device for fixing a recorded yellow thermosensitive coloring layer is arranged between the yellow thermal head and the magenta sall head. A magenta fixing device for fixing the color forming layer is arranged.

On the color thermosensitive recording paper pulled out from the roll, a yellow image is color-recorded line by line in an image recording area by a yellow thermal head. After the yellow image is recorded, the recorded yellow thermosensitive coloring layer is fixed by the yellow fixing device. Next, after a magenta image is color-recorded with a magenta thermal head,
The magenta thermosensitive coloring layer is fixed by the magenta fixing device.
Finally, the cyan image is color-recorded by the cyan thermal head, then cut into image recording areas by an exit cutter arranged near the paper discharge port, and discharged as one sheet recording paper to the outside.

[0007]

The yellow fixing device and the magenta fixing device need to uniformly fix the inside of the image recording area. In this case, the ultraviolet rays may be irradiated until the rear end of the image recording area passes through the fixing device.

However, if ultraviolet light is irradiated until the rear end of the image recording area passes through the fixing device, the unrecorded part behind the image recording area is also irradiated with ultraviolet light. It can no longer be used, wasting material.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color thermal printer which is devised so as to eliminate waste of the color thermal recording paper.

[0010]

In order to achieve the above object, according to the present invention, there is provided a light-shielding position for blocking ultraviolet rays by entering between a fixing device and a color thermosensitive recording paper, and a retreating position retracted from between them. An exposure-preventing shutter movable between the shutter-driving roller, a shutter-driving roller rotating in contact with one of the pair of transport rollers, and a nip of the exposure-preventing shutter between the shutter-driving roller and the rear end of the image recording area. A shutter mechanism comprising a nip roller for moving the exposure prevention shutter in the same direction at the same speed as the color thermosensitive recording paper in the same direction with the leading end of the prevention shutter and setting it at the light shielding position is provided. As described above, since the shutter mechanism for preventing the unrecorded portion after the rear side of the image recording area from being fixed is provided, the unrecorded portion of the image recording area is not fixed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 2, a color thermosensitive recording paper 15 has a cyan thermosensitive coloring layer 17, a magenta thermosensitive coloring layer 18, a yellow thermosensitive coloring layer 19, and a protective layer 20 on a support 16 in order. It is layered. Each thermosensitive coloring layer 18-2
0 is provided in the order of thermal recording. For example, when thermal recording is performed in the order of magenta, yellow, and cyan, the yellow thermosensitive coloring layer 19 and the magenta thermosensitive coloring layer 18 are provided.
Is replaced. Each of these thermosensitive coloring layers 17 to 19
The deeper the layer, the higher the color heat energy, and by changing the color heat energy given by the thermal head, it is possible to selectively color the three color heat-sensitive color layers.

In FIG. 1 showing the outline of a printer, three thermal heads 21 to 23 for yellow, magenta and cyan are arranged at a substantially constant interval along a linear transport path (path). The transport roller pair 2 is disposed so as to be located on the downstream side of each of the thermal heads 21 to 23.
4 to 26 are provided. Transport roller pair 24-26
Comprises a captain roller and a pinch roller. The color thermosensitive recording paper 15 is drawn out of the recording paper roll 29 to a transport path by a paper feed roller pair 28 rotated by a motor 27, and is transported toward the transport roller pairs 24 to 26. These conveying roller pairs 24 to 26 are rotated at a constant speed by pulse motors 30 to 32, respectively, after the pinch roller is shifted to nip the color thermosensitive recording paper 15.

Vertical thermal head 2 for yellow
Heating element arrays 21 a to 23 a in which a large number of heating elements are arranged in a line are provided at the lower ends of the thermal head 22 for magenta and the thermal head 23 for cyan. Each of the heating element arrays 21 a to 23 a extends in the width direction of the color thermosensitive recording paper 15.

The thermal heads 21 to 23 are vertically moved by shift mechanisms 33 to 35 such as solenoids and cams. At the time of printing, it is moved to a position pressed against the color thermosensitive recording paper 15, and at the end of printing, to a position away from the color thermosensitive recording paper 15.

A fixing device 3 for yellow is provided between the thermal head 21 for yellow and the thermal head 22 for magenta.
7, a magenta fixing device 38 is disposed between the magenta thermal head 22 and the cyan thermal head 23. The yellow fixing device 37 is composed of two rod-shaped ultraviolet lamps 39 and 40 and a lamp house 41 which emit near-ultraviolet light having an emission peak of approximately 420 nm. The magenta fixing device 38 has an emission peak of about 365 n.
Two UV lamps 4 in the shape of rods that emit UV light
2 and 43 and a lamp house 44. Each of the lamp houses 41 and 44 has an opening on the side facing the color thermosensitive recording paper 15. The number of lamps for fixing the heat-sensitive coloring layers by light is not limited to two, but may be one or three.

Platen rollers 46 to 48 are disposed at positions facing the thermal heads 21 to 23, respectively. These platen rollers 46 to 48 are rotatably supported. The platen rollers 46 to 48
May be driven by a motor.

A thermal head 21 for yellow, a thermal head 22 for magenta, and a thermal head 23 for cyan
Are provided with reflection-type tip detection sensors 49 to 51, respectively. The tip detection sensors 49 to 51 are
Each is provided with a light projecting section and a light receiving section, and detects that the leading end of the color thermosensitive recording paper 15 comes to a point where two optical axes intersect. From the time when this tip is detected, the motors 30 to 32
By counting the driving pulses of the thermal head 2
The starting position of up-down and thermal recording of 1 to 23 is determined.

Fixing device 37 and magenta thermal head 2
2, a guide plate 53 and a guide roller 5
4 are arranged. When there is a difference in transport speed between the thermal heads 21 and 22,
In order to prevent a change in the transport load caused by the up and down movement of the transport roller pair 25 and the guide roller 54,
The slack 55 of the color thermosensitive recording paper 15 is formed between the two. Similarly, the fixing device 38 and the thermal head 23 for cyan
Between the guide plate 56 and the guide roller 57
Are disposed, and the slack 58 is placed on the guide plate 56.
To form These slacks 55 and 58 absorb variations in the transport load caused by the behavior of the thermal heads 21 to 23, so that it is possible to prevent the occurrence of streak-like density unevenness due to the variations in the transport load.

On the downstream side of the transport roller pair 26, a reflection type photosensor 60 and an exit cutter 61 are arranged in order along the transport direction. The photo sensor 60 optically detects that the leading end of the color thermosensitive recording paper 15 has come.
The exit cutter 61 cuts the color thermosensitive recording paper 15 based on the detection of the leading edge by the photo sensor 60, and separates the recording paper into image recording areas to form sheet recording paper. A transport roller pair 65 and a discharge roller pair 62 are provided before and after the photosensor 60 and the exit cutter 61. The transport roller pair 65 transports the color thermosensitive recording paper 15 toward the discharge roller pair 62 by driving a motor 67. The discharge roller pair 62 is rotated by driving of the motor 63, and conveys the cut sheet recording paper toward the discharge port 64.

From the time when the leading end is detected by the photosensor 60, the drive pulse of the motor 63 is counted and the feed amount is measured, and then the exit cutter 61 is operated, so that each image recording area can be cut. it can. Exit cutter 6
At the time of cutting 1, the driving of the motors 63 and 67 is stopped,
The conveyance of the color thermosensitive recording paper 15 is stopped. In order to absorb the slack caused by this stop, the transport roller pair 2
6, 65, a dancer roller 66 is provided.

A leading end detection sensor 68 is arranged downstream of the sheet feeding roller pair 28. Color thermal recording paper 15
In the case of continuous printing, after the last image recording area is cut off, the leading end is returned from the exit cutter 61 toward the sheet feeding roller pair 28. When the leading edge detection sensor 68 detects the leading edge of the color thermal recording paper 15 during the reverse transport, the reverse transport of the color thermal recording paper 15 is stopped. Also in the case of one-sheet printing, after the cutting of the image recording area, the leading end of the color thermosensitive recording sheet is returned to the position of the leading end detection sensor 68.

Each of the fixing units 37 and 38 is provided with shutter mechanisms 70 and 71 for preventing exposure. Since these shutter mechanisms 70 and 71 have the same structure, only one of the shutter mechanisms 71 shown enlarged in FIG. 1 will be described here. The shutter mechanism 71 includes a shutter curtain 74, a pair of guide members 76, and a pair of shutter transport rollers 78. The shutter transport roller pair 78 includes a nip roller 80 and a shutter drive roller 82. The nip roller 80 is moved by a shift mechanism 84 between a position where the shutter curtain 74 is nipped with the shutter driving roller 82 and a retracted position where the shutter curtain 74 is retracted from the position. A part of the outer periphery of the shutter drive roller 82 is in sliding contact with the outside of the shutter curtain 74, and the outer periphery of the pinch roller 25a also comes into contact when the pinch roller 25a of the transport roller pair 25 nips the color thermosensitive recording paper 15. I do. The shutter curtain 74 moves in the same direction at the same speed as the color thermosensitive recording paper 15.

As shown in FIG. 3, the pair of guide members 76 have a C-shaped cross section with the open side facing the downstream side, and guide grooves 76a for guiding both ends of the shutter curtain 74 to the inside facing each other. Are formed respectively. The shutter curtain 74 is a sheet formed of a black flexible material, for example, plastic, metal, or the like.
4 moves between a shielding position where it enters below the fixing area 90 and shields the fixing area 90, and a retreat position where it escapes obliquely upward along the V-shaped guide groove 76a and retreats from the fixing area 90 as shown in FIG. It is free. Above the guide member 76, a home position sensor 91 for detecting a retracted position of the shutter curtain 74 is attached. The shift mechanism 84 receives the evacuation signal from the home position sensor 91 when the color thermosensitive recording paper 15 is conveyed in the reverse direction, and moves the nip roller 80 to the evacuation position. As described above, since the shutter curtain 74 is moved in a U-shape around the fixing units 37 and 38, the fixing unit 3 is attached to the transport roller pairs 24 and 25.
7, 38 can be arranged close to each other, and the size of the printer can be reduced.

The operation of the above configuration will be described. The initial state is
In a state where the color thermosensitive recording paper 15 is nipped by the paper feed roller pair 28, the front end faces the front end detection sensor 68. In the shutter mechanisms 70 and 71, the shutter curtain 74 is set at the retracted position, and the nip roller 80 is also at the retracted position.

When continuous printing is instructed, the driving of the conveying roller pairs 24 to 26 and the like are started at the same time, and the ultraviolet lamps 39, 40, 42, and 43 are turned on. And
The motor 27 is driven, and the color thermosensitive recording paper 15 is pulled out from the recording paper roll 29 by the rotation of the paper feed roller pair 28.

Immediately after the drawing out of the color thermosensitive recording paper 15 is started, the leading end thereof is detected by the leading end detecting sensor 49. The counter counts the number of motor drive pulses of the pulse motor 30 from the time when the leading edge detection sensor 49 detects. When the count value reaches a value corresponding to a predetermined length, the pinch roller of the conveying roller pair 24 is moved to the nip position, and the recording paper 15 is moved between the pinch roller and the captain roller.
In between. At the same time, the shift mechanism 33 moves down the yellow thermal head 21 to press the heating element array 21 a against the color thermosensitive recording paper 15. After nipping the color thermosensitive recording paper 15 by the transport roller pair 24, the rotation of the paper feed roller pair 28 is made free.

Then, the color thermosensitive recording paper 15 is further fed, and the count value of the number of motor drive pulses of the pulse motor 30 is determined by the amount of conveyance in which the leading end of the image recording area reaches the heating element array 21a of the yellow thermal head 21. Is reached, the heating element array 21a generates heat according to the thermal sensitivity of the yellow thermosensitive coloring layer 19, and color-records a yellow image line by line in the image recording area.

When the image recording area on which the yellow image is color-developed reaches the yellow fixing unit 37, near ultraviolet rays of about 420 nm are irradiated on the color thermosensitive recording paper 15 from the ultraviolet lamps 39 and 40, and the next magenta thermosensitive coloring is performed. Layer 1
In the thermal recording of No. 8, fixing is performed to such an extent that the yellow thermosensitive coloring layer 19 does not develop color. After the fixing, the sheet is conveyed toward the magenta thermal head 22 so as to form a slack 55 between the guide roller 54 and the conveying roller pair 25.

If the leading edge of the color thermosensitive recording paper 15 is detected by the leading edge detection sensor 50 during the transport, the pinch roller 25a of the transport roller pair 25 is moved to the captain roller 25b.
The color thermosensitive recording paper 15 is nipped between them. At the same time, the shift mechanism 34 sets the magenta thermal head 22
To press the heating element array 22 a against the color thermosensitive recording paper 15. Then, the color thermosensitive recording paper 15 is further fed, and the count value of the number of motor drive pulses of the pulse motor 31 corresponds to the transport amount by which the leading end of the image recording area reaches the heating element array 22a of the magenta thermal head 22. When this value is reached, the heating element array 22a generates heat in accordance with the thermal sensitivity of the magenta thermosensitive coloring layer 18, and color-records magenta images line by line in the image recording area.

When the image recording area reaches the magenta fixing device 71, almost 365n from the ultraviolet lamps 42 and 43 are reached.
Ultraviolet rays in the vicinity of m are radiated to the color thermosensitive recording paper 15, and are fixed so that the magenta thermosensitive coloring layer 19 does not develop color during the subsequent thermal recording of the cyan thermosensitive coloring layer 18. After the fixing, the slack 58 between the guide roller 57 and the conveying roller pair 26 is obtained.
Is formed, the color thermosensitive recording paper 15 is transported toward the cyan thermal head 23.

During the transport, the tip is detected by the tip detection sensor 51.
Is detected, the transport roller pair 26 nips the color thermal recording paper 15, and the thermal head 23 for cyan descends by the shift mechanism 35 to move the color thermal recording paper 1.
5 is pressed. When the leading end of the image recording area reaches the heating element array 23a of the cyan thermal head 23, the heating element array 23a generates heat in accordance with the thermal sensitivity of the cyan thermosensitive coloring layer 17, and one cyan image is stored in the image recording area. Color recording is performed line by line. This cyan thermosensitive coloring layer 1
No. 7 has a value at which the coloring heat energy does not form a color in a normal storage state, so that the cyan thermosensitive coloring layer 17 is not provided with a light fixing property.

As described above, the three thermal heads 21 to
23, three color images are recorded in an overlapping state in the image recording area, and a full-color image is formed. Thereafter, when the leading end of the color thermosensitive recording paper 15 is conveyed by the conveying roller pair 65, a slack is formed by the dancer roller 66, and then the recording paper 15 is conveyed toward the discharge roller pair 62.

The photo sensor 50 is a color thermosensitive recording paper 15
The number of motor drive pulses of the pulse motor 65 is counted by the counter from the time when the leading end of the image recording area is detected. When it is confirmed from the count value that the rear end of the image recording area has reached the cut position, the driving of the motors 63 and 67 is stopped. Then, the conveyance of the color thermosensitive recording paper 15 by the conveyance roller pair 65 and the discharge roller pair 62 is temporarily stopped. During this time, the exit cutter 61 is operated to cut the color thermosensitive recording paper 15 into sheet recording paper for each frame. Motors 63 and 6 again
7 is driven, and the cut sheet recording paper is discharged toward the discharge port 64 by the discharge roller pair 62.

The color thermosensitive recording paper 15 is a recording paper roll 2
9 while passing through the yellow thermal head 21, the yellow fixing unit 37, the magenta thermal head 22, the magenta fixing unit 38, and the cyan thermal head 23 sequentially, a plurality of full-color images It is recorded in the image recording area. Each full color image is
The paper is sequentially cut by the exit cutter 61 and discharged as sheet recording paper.

During the recording of each full-color image, the color thermosensitive recording paper 15 is pulled out from the roll 29 by a predetermined number of lengths, and the final line of the yellow image is recorded by the yellow thermal head 21 in the last image recording area. After that, the shutter mechanism 70 is operated to shield the unrecorded portion after the rear end of the last image recording area from being irradiated with ultraviolet rays from the fixing device 37.

That is, the thermal head 21 for yellow
Assuming that the distance from the heating element array 21a to the tip of the fixing area (ultraviolet irradiation area) is L1 and the length of the guide groove from the tip of the shutter curtain 74 to the tip of the fixing area is L2, the last line of the yellow image is recorded. The shift mechanism 84 moves the nip roller 80 to the nip position when the color thermosensitive recording paper 15 is conveyed by the length (L1-L2) after the transfer. At this time, the shutter driving roller 82
When the nip roller 80 is moved to the nip position, the shutter curtain 74 slides between the shutter driving roller 82 and the shutter curtain 74 because the nip roller 80 slides on the pinch roller 24 a of the transport roller pair 24 and idles.
Is nipped, and the shutter curtain 74 moves toward the shielding position.

The transport roller pair 24 and the shutter transport roller pair 78 rotate at the same speed. For this reason, the shutter curtain 74 is moved at the same speed in the same direction as the transport direction of the color thermosensitive recording paper 15 with the leading end aligned with the end of the last image recording area, and moves within the fixing area of the yellow fixing device 37. Get in. As a result, the image is fixed with uniform illuminance up to the end of the last image recording area, and the unfixed portion after the end is blocked by the shutter curtain 74 from light fixing. When the shutter curtain 74 reaches the shielding position, the shutter curtain 74 contacts the edge of the guide groove 76a and is maintained at the shielding position. During this time, the nip roller 80 escapes and slips with the shutter curtain 74. It should be noted that a sensor for detecting the leading end of the shutter curtain 74 is provided,
The shift mechanism may be operated by a signal from a sensor to retract the pinch roller 80.

After the magenta thermal head 22 records a magenta image in the last image recording area, the shutter mechanism 71 operates. The magenta shutter mechanism 71 also moves in the same direction at the same speed with the leading end of the shutter curtain aligned with the leading end of the image recording area, and the unrecorded portion is not exposed to ultraviolet light, in application to the shutter mechanism 70 for yellow. Thus, the magenta fixing device 38 is shielded from light.

The last image recording area is cut by the exit cutter 61 after the cyan image is recorded by the cyan thermal head 23. After this cutting, the motor 63
To discharge only the sheet recording paper on which the last image is recorded by the discharge roller pair 62 toward the discharge port 64. Since the color thermosensitive recording paper 15, which is the remaining unrecorded portion, has not been subjected to optical fixing, the motors 30 to 32, 67 are rotated in reverse to feed the unfixed color thermosensitive recording paper 15 to the paper feed roller pair 2.
Return to 8. At the time when the reverse rotation drive is started, the lamps 30, 40, 42, 43 of the fixing units 37, 38 are turned off. When the leading edge of the color thermosensitive recording paper 15 is detected by the leading edge detection sensor 68, the motors 30 to 32, 67
Stop reverse rotation drive.

Since the rotation of the pair of transport rollers 24 and 25 is transmitted to the pair of shutter transport rollers 78, the shutter curtain 74 of the shutter mechanisms 70 and 71 is moved toward the retracted position. Then, when the movement of the shutter curtain 74 to the retreat position is detected by the home position sensor 91, the shift mechanism 84 retreats the nip roller 80 from the nip position. In the retracted position, the position of the shutter is held by a shutter holding member (not shown).

Similarly, when printing only one frame, the shutter mechanisms 70 and 71 can be operated to prevent the rear side of the image recording area where the full-color image has been recorded from being irradiated with ultraviolet rays.

In the above embodiment, a three-head, one-pass type color thermal printer is used. However, the present invention is not limited to this, and color recording is performed by reciprocating the color thermal recording paper three times with respect to one thermal head. Can also be applied to the one-head three-pass method.

[0043]

As described in detail above, the present invention provides
A shutter for blocking ultraviolet rays from the fixing device; and a pair of shutter transport rollers for nipping the shutter and moving it between a retracted position and a light shielding position. The color thermal recording paper and the shutter are moved in the same direction at the same speed by contacting one of the rollers of the pair of transport rollers for transporting the unrecorded portion on the rear end side of the image recording area. Since the light is shielded as described above, the unrecorded portion can be used for the next recording, and therefore, the waste of the color thermosensitive recording paper can be eliminated.

Further, a pair of U-shaped guide members are used so as to surround the fixing device, and the shutter is moved in a U-shape by the guide members, so that the shutter is moved in parallel with the color thermosensitive recording paper. As a result, the space for disposing the shutter mechanism is reduced, and as a result, the color thermal printer can be downsized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an outline of a configuration of a printer.

FIG. 2 is a cross-sectional view of a color thermosensitive recording paper.

FIG. 3 is a perspective view showing a main part of a shutter mechanism in which a shutter curtain has been moved to a shielding position.

FIG. 4 is a perspective view showing a main part of a shutter mechanism in which a shutter curtain has been moved to a retracted position.

[Explanation of symbols]

 Reference Signs List 15 color thermal recording paper 21-23 thermal head 24-26,65 transport roller pair 37,38 fuser 61 outlet cutter 70,71 shutter mechanism 74 shutter curtain 78 shutter transport roller pair 80 shutter drive roller 81 nip roller

Claims (3)

[Claims] 1. A color thermosensitive recording paper roll on which at least three thermosensitive coloring layers having different thermal sensitivities and colors to be formed are laminated, and the color thermosensitive recording paper drawn from the roll is reciprocated substantially linearly. A transport roller pair to be heated, a thermal head for selectively coloring and recording the thermosensitive coloring layer in the image recording area, and an image recording of ultraviolet rays specific to the recorded thermosensitive coloring layer before coloring the next thermosensitive coloring layer. A color fixing device comprising: a fixing device that irradiates and fixes the image in the area; and a cutter that cuts a rear end side of an image recording area in which a full-color image is sequentially recorded in three color planes and cuts the sheet into sheets. An exposure-prevention shutter movable between a light-shielding position that intercepts ultraviolet light by entering between the recording paper and the color thermosensitive recording paper, and a retracted position that is retracted from between them; The exposure drive shutter is nipped between the shutter drive roller that rotates in contact with one of the shutter drive rollers, and color thermal recording is performed with the rear end of the image recording area and the front end of the exposure prevention shutter aligned. A color thermal printer comprising a shutter mechanism comprising a nip roller for moving an exposure prevention shutter at substantially the same speed as paper in the same direction and setting it at a light blocking position. 2. A roll of color thermosensitive recording paper having at least a second or third thermosensitive coloring layer having different thermal sensitivities and different colors to be formed, and the rolls are sequentially arranged between the roll and the discharge port. A first to a third transport roller pair for transporting the color thermosensitive recording paper drawn out from the roll toward a downstream paper discharge port, and a first to a third transport roller pairs disposed upstream of each transport roller pair in the image recording area. The first to third thermal heads for selectively recording the three thermosensitive coloring layers, the first transporting roller pair and the second thermal head are disposed between the first and third thermal heads. A first fixing device that irradiates the image recording area to fix the first thermosensitive coloring layer on which color recording has been performed, and is disposed between the second conveying roller pair and the third thermal head, and the second thermosensitive coloring of the intermediate layer is performed. UV light peculiar to the layer is illuminated in the image recording area. A second fixing device for fixing the second thermosensitive coloring layer on which the color recording is performed, and a cutter for cutting the rear end side of the image recording area where a full-color image is recorded in three color planes sequentially and cutting the sheet into a sheet. In the color thermal printer, a shutter mechanism is provided in each of the first and second fixing units, and each shutter mechanism is provided between a fixing unit and a color thermosensitive recording paper and a light-shielding position for blocking ultraviolet rays. An exposure prevention shutter movable between the retracted retracted position, a shutter driving roller rotating in contact with one of the conveying roller pairs, and an exposure prevention shutter nip between the shutter driving roller and the image recording area. With the rear edge of the shutter and the front end of the exposure prevention shutter aligned, move the exposure prevention shutter in the same direction at approximately the same speed as the color thermal recording paper and set it at the light-shielding position. And a nip roller for carrying out the operation. 3. The shutter mechanism includes a pair of U-shaped guide members for guiding both sides of an exposure prevention shutter,
3. The color thermal printer according to claim 1, wherein a fixing device is disposed in the guide member.