JP3467127B2 - Color thermal printer - Google Patents

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 thermally records a color thermal recording material and then radiates ultraviolet rays to perform optical fixing.

[0002]

2. Description of the Related Art In a color thermal printer, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer and a yellow thermosensitive coloring layer are sequentially formed on a support so that a full-color image can be directly heat-recorded. A color thermosensitive recording material is used. With this color thermosensitive recording material, thermal recording is performed in order from the thermosensitive coloring layer on the front surface side, but at the time of thermorecording on the next thermosensitive coloring layer, the thermosensitive coloring layer on which the thermorecording has been completed does not record again. Therefore, after the thermal recording, the coloring ability is lost by irradiating each thermosensitive coloring layer with ultraviolet rays in a wavelength range peculiar to each layer.

In a conventional color thermal printer, a rod-shaped ultraviolet lamp is used to generate ultraviolet rays for optical fixing. This ultraviolet lamp is, for example, Jikken Sho 63-3.
As described in Japanese Patent No. 3321, it has a characteristic that the emission intensity changes according to the change of the tube wall temperature. In addition, the emission intensity of the ultraviolet lamp varies depending on the axial position of the tube. The emission intensity is large at the center of the tube and relatively stable, but the emission intensity rapidly decreases near the ends. In order to perform uniform optical fixing without being affected by such characteristics, for example, Japanese Patent Publication No.
As described in Japanese Patent No. 54590, there is known a method in which a sensor for measuring illuminance is arranged in the vicinity of an ultraviolet lamp and the emission intensity of the lamp is controlled according to the measured value.

[0004]

The illuminance sensor is generally arranged on the back side of the ultraviolet lamp so as not to be located on the color thermosensitive recording material. The light incident on the illuminance sensor includes not only the light emitted from the ultraviolet lamp but also the reflected light from the color thermosensitive recording material. The reflected light includes light from a recorded image portion and light from a white frame portion on which no image is recorded, and these have different intensities. Further, even if the reflected light is from the same image portion, its intensity varies depending on the shade of the image. Therefore, the illuminance cannot be measured correctly, and therefore the emission intensity of the ultraviolet lamp cannot be properly controlled.

There is also a method of arranging the illuminance sensor near the end of the ultraviolet lamp so as not to face the color thermosensitive recording material in order to avoid the incidence of reflected light from the color thermosensitive recording material.

As described above, near the end of the ultraviolet lamp, the emission intensity varies greatly with the change in tube wall temperature. In particular, when the temperature of the tube wall is low, such as immediately after the ultraviolet lamp starts to emit light, the emission intensity is extremely low near the edge compared to the central part, and based on the illuminance at this edge, When the emission intensity of the ultraviolet lamp is adjusted, over-fixing occurs in the central portion of the tube, and in fixing a yellow image, the coloring ability of the magenta thermosensitive coloring layer is diminished.

The present invention has been made in consideration of the above circumstances, and is a color capable of performing stable optical fixing by maintaining an appropriate emission intensity of ultraviolet rays applied to a color thermosensitive recording material. It is an object to provide a thermal printer.

[0008]

In order to achieve the above object, the color thermal printer of the present invention comprises a rod-shaped ultraviolet lamp arranged with both ends protruding from the side edges of the color thermal recording material, and the ultraviolet lamp. A first illuminance sensor that measures the illuminance of ultraviolet rays emitted from the central part in the axial direction of the lamp, a second illuminance sensor that measures the illuminance of ultraviolet rays emitted from the end of the ultraviolet lamp, and the front surface of the ultraviolet lamp. The UV lamp is dimmed according to the measurement value of the first illuminance sensor when the recording area of the color thermosensitive recording material is not located, and according to the measurement value of the second illuminance sensor when the recording area is located. And a control means for performing the operation.

A color thermal printer according to a second aspect of the present invention comprises a rod-shaped ultraviolet lamp that emits ultraviolet rays, a reflector that reflects the ultraviolet rays emitted behind the ultraviolet lamp toward the color thermal recording material, and an ultraviolet lamp. An opening formed in the reflector for passing the ultraviolet light emitted in the horizontal direction with the color thermosensitive recording material from the central part in the axial direction, and the illuminance of the ultraviolet light emitted from the ultraviolet lamp in the horizontal direction, which is arranged outside this opening. An illuminance sensor that measures the illuminance and a control unit that adjusts the emission intensity of the ultraviolet lamp according to the measurement value of the illuminance sensor are provided.

[0010]

FIG. 2 is a schematic diagram showing the structure of a color thermal printer of the present invention. A sheet-shaped color thermosensitive recording material 10 is stacked in a paper feed tray 11. A paper feed roller 12 is provided above the paper feed tray 11 and rotates at the start of printing to feed the uppermost color thermosensitive recording material 10 from the paper feed path 13. The color thermosensitive recording material 10 sent out from the paper feeding path 13 is
Nip rollers 14a and 15a and drive rollers 14b and 15
n is nipped by two pairs of conveyance rollers 14 and 15 composed of b and b, and a forward direction from the paper feed tray 11 side to the paper discharge passage 16 side and a reverse direction from the paper discharge passage 16 side to the paper feed tray 11 side. It is transported alternately.

A small diameter platen roller 17 and a color thermosensitive recording material 10 supported on the platen roller 17 are pressed between the first conveying roller pair 14 and the second conveying roller pair 15 to record an image. A thermal head 18 is provided. As is well known, the thermal head 18 is formed by arranging a large number of heating elements in a line, and generates thermal energy according to the color to be thermally recorded and its color density. As shown in FIG. 3, the thermal recording by the thermal head 18 is performed only in the recording area 10a of the color thermosensitive recording material 10, and the margin 10b is left in the peripheral portion. The drive rollers 14b and 15b and the platen roller 17 are rotated in the same direction by the conveyance motor 19 at the same peripheral speed.

Two optical fixing devices 30 and 40 are arranged between the second conveying roller pair 15 and the paper discharge passage 16.
The yellow optical fixing device 30 emits ultraviolet rays having an emission peak at about 420 nm and the magenta optical fixing device 40 emits ultraviolet rays having an emission peak at about 365 nm, and irradiates the color heat-sensitive recording material 10.

As shown in FIG. 1, a yellow optical fixing device 3
0 is a rod-shaped ultraviolet lamp 31, a reflector 32 arranged behind it, and two illuminance sensors 33 and 34.
And a sensor 35 for detecting the tip of the color thermosensitive recording material 10. The emission intensity of the ultraviolet lamp 31 fluctuates due to changes in the tube wall temperature. For example,
When the temperature of the tube wall of the ultraviolet lamp 31 is low, such as immediately after the start of light emission, as shown in FIG. The emission intensity decreases as the temperature approaches. Then, as the temperature of the tube wall of the ultraviolet lamp 31 rises, the emission intensity in the central portion 31a generally approaches, and the emission intensity in the range X excluding both end portions 31b and 31c as shown in FIG. Stabilizes in a nearly constant state.
The color thermosensitive recording material 10 is positioned within the range where the emission intensity of the ultraviolet lamp 31 is stable, and both ends 31b, 3
1c is arranged so as to protrude from both side edges of the color thermosensitive recording material 10.

The reflector 32 has an opening 32a formed at the center of the upper wall thereof and is arranged so as to cover the range X of the ultraviolet lamp 31. The inner wall of the reflector 32 is a reflecting surface, and reflects the light emitted to the rear of the ultraviolet lamp 31 toward the color thermosensitive recording material 10 side.

The first illuminance sensor 33 includes a reflector 32.
The second illuminance sensor 34 is arranged outside the opening 32a formed in the upper wall, below the ultraviolet lamp 31, and beside the side edge of the color thermosensitive recording material 10. The illuminance sensors 33 and 34 measure the illuminance of ultraviolet rays emitted from the ultraviolet lamp 31 and send respective illuminance signals to the microcomputer 50.

The sensor 35 is provided on the discharge passage 16 side of the ultraviolet lamp 31, and the distance between the sensor 35 and the ultraviolet lamp 31 is from the front end of the color thermosensitive recording material 10 to the recording area 1.
It is arranged so as to be almost the same as the length L up to 0a (see FIGS. 2 and 3). A low level signal (hereinafter referred to as "L" signal) is set when the color thermosensitive recording material 10 is placed on the sensor 35, and a high level signal (hereinafter referred to as "H" signal) when the color thermosensitive recording material 10 is not placed. ) Is sent to the microcomputer 50. Since the magenta optical fixing device 40 has the same structure, only the reference numeral is given.

The microcomputer 50 includes a sensor 35.
Lamp control signal according to the illuminance signal of the first illuminance sensor 33 when the "H" signal is input, and lamp control according to the illuminance signal of the second illuminance sensor 34 when the "L" signal is input from the sensor 35. The signal is sent to the driver 51. The driver 51 adjusts the duty ratio of the drive pulse supplied to the ultraviolet lamp 31, for example, according to the lamp control signal, and controls the emission intensity of the ultraviolet lamp 31 so that the illuminance is maintained at a predetermined value. . Similarly, the microcomputer 50 selects either the illuminance sensor 43 or 44 based on the output signal from the sensor 45 and sends a lamp control signal corresponding to the illuminance signal to the driver 52.
The emission intensity of the ultraviolet lamp 41 is controlled.

FIG. 5 shows an example of the layer structure of the color thermosensitive recording material 10. The color thermosensitive recording material 10 is
A cyan thermosensitive coloring layer 61, a magenta thermosensitive coloring layer 62, a yellow thermosensitive coloring layer 63, and a protective layer 64 are sequentially laminated on the support 60. Each of these thermosensitive coloring layers 61
Nos. 63 to 63 are layered from the surface in the order of thermal recording. For example, when thermal recording is performed in the order of magenta, yellow, and cyan, the positions of the yellow thermosensitive coloring layer 63 and the magenta thermosensitive coloring layer 62 are Can be replaced. An intermediate layer (not shown) is provided between the layers.

The cyan thermosensitive coloring layer 61 contains an electron-donating dye precursor and an electron-accepting compound as main components, and develops cyan when heated. Magenta thermosensitive coloring layer 6
No. 2 contains a diazonium salt compound having a maximum absorption wavelength of about 365 nm, and a coupler which thermally reacts with this compound to develop magenta color. This magenta thermosensitive coloring layer 62
When a magenta image is thermally recorded by the thermal head 18 and then irradiated with ultraviolet rays in the vicinity of 365 nm, the diazonium salt compound is photodecomposed and the coloring ability is lost. The yellow thermosensitive coloring layer 63 contains a diazonium salt compound having a maximum absorption wavelength of about 420 nm, and a coupler that thermally reacts with this compound to develop yellow. The yellow thermosensitive coloring layer 63 also undergoes photolysis when irradiated with ultraviolet rays in the vicinity of 420 nm and loses its coloring ability. In addition, each thermosensitive coloring layer 61 to
Thermal head 18 required for developing 63
The yellow heat-sensitive color developing layer 63 has the lowest amount of heat energy, and the cyan heat-sensitive color developing layer 61 has the highest amount of heat energy.

Next, the operation of this embodiment will be described. When printing is instructed, the paper feed roller 12 and the first transport roller pair 14 rotate. The color thermosensitive recording material 10 stacked on the uppermost part of the paper feed tray 11 is sent out from the paper feed passage 13. The process ends when the front end of the color thermosensitive recording material 10 is nipped by the second conveying roller pair 15. After the paper feed, the drive roller 15b and the platen roller 17 are rotated by the motor 19 to start the yellow image printing process. At the same time, the ultraviolet lamp 31 of the yellow optical fixing device 30 starts to emit light. Then, the illuminance of the ultraviolet light emitted from the ultraviolet lamp 31 is measured by the illuminance sensor 33,
Measured by 34, the respective illumination signals are sent to the microcomputer 50. Further, the sensor 35 for detecting the leading edge also operates and sends the detection signal to the microcomputer 50. Immediately after the start of printing, the sensor 35
Since the color thermosensitive recording material 10 is not located on the front surface of the sensor, this sensor 35 outputs the "H" signal.

The microcomputer 50 includes a sensor 35.
Since the "H" signal is output from the driver 5, the lamp control signal is output to the driver 5 based on the illuminance signal of the first illuminance sensor 33.
Then, the light intensity is adjusted so that the emission intensity of the ultraviolet lamp 31 becomes a predetermined value. At this time, the microcomputer 50
Greatly adjusts the emission intensity of the ultraviolet lamp 31 when the illuminance measured by the illuminance sensor 33 is less than the specified illuminance, and suppresses the emission intensity when the illuminance exceeds the specified illuminance. Since the temperature of the tube wall is low immediately after the ultraviolet lamp 31 starts to emit light, as shown in FIG. 4 (A), the central portion 31a of the tube and the end portions 31b and 31c have significantly different emission intensities. However, since the first illuminance sensor 33 faces the central portion 31a of the ultraviolet lamp 31, the microcomputer 50 can directly monitor the illuminance by the central portion 31a having the highest emission intensity. Therefore, the emission intensity within the range X facing the color thermosensitive recording material 10 is adjusted to an appropriate intensity without becoming excessive.

When the tip of the recording area 10a reaches the thermal head 18, the thermal head 18 rotates clockwise to press the color thermosensitive recording material 10 to heat the yellow image on the yellow thermosensitive coloring layer 63 line by line. Record. In the thermal recording of this yellow image, the thermal head 1
Each heating element 8 generates heat energy corresponding to the color density. The portion on which the yellow image is thermally recorded is nipped by the second conveying roller pair 15 and continuously conveyed, and when it reaches the ultraviolet lamp 31, the yellow thermosensitive coloring layer 63 is optically fixed.

Since the "H" signal is being output from the sensor 35 until the tip of the color thermosensitive recording material 10 passes through the ultraviolet lamp 31 and reaches the sensor 35, the microcomputer 50 outputs the first illuminance sensor. The illuminance of ultraviolet rays emitted from the ultraviolet lamp 31 is monitored based on the measured value of 33. At this time, since the color thermosensitive recording material 10 is contained in the irradiation area of the ultraviolet lamp 31, the reflected light from the color thermosensitive recording material 10 is also incident on the first illuminance sensor 33. Since this reflected light is from the margin 10b of the color thermosensitive recording material 10, the first illuminance sensor 3
The intensity of the reflected light entering 3 is constant and does not fluctuate irregularly. Therefore, the ultraviolet lamp 31
Stable dimming.

The tip of the recording area 10a is the ultraviolet lamp 3
When it reaches 1, the color thermosensitive recording material 10
Since the tip of the sensor is detected by the sensor 35, the output signal of the sensor 35 changes from the "H" signal to the "L" signal. At this time, the microcomputer 50 controls the ultraviolet lamp 31 based on the illuminance signal of the second illuminance sensor 34 instead of the first illuminance sensor 33.

At this time, since the second illuminance sensor 34 is arranged beside the side edge of the color thermosensitive recording material 10, the light emitted from the ultraviolet lamp 31 and reflected by the image portion in the recording area 10a is second. It does not enter the illuminance sensor 34. Further, since the tube wall temperature of the ultraviolet lamp 31 is raised during the transportation of the color thermosensitive recording material 10, the emission intensity of the ultraviolet lamp 31 is stable in the state shown in FIG. The ratio between the emission intensity L _S at the position facing the sensor 34 and the emission intensity L _max in the range X facing the color thermosensitive recording material 10 is always constant. Therefore, if the emission intensity of the ultraviolet lamp 31 is adjusted based on the measurement value of the second illuminance sensor 34 in consideration of the ratio of the emission intensity, the emission intensity L _max in the range X facing the color thermosensitive recording material 10 is defined. The dimming can be performed accurately and stably so that the value becomes a value.

The color thermosensitive recording material 10 is optically fixed in the recording area 10a while passing through the front surface of the ultraviolet lamp 31. The ultraviolet lamp 31 irradiates ultraviolet rays of approximately 420 nm, and photolyzes the diazonium salt compound contained in the yellow thermosensitive coloring layer 63 to eliminate the coloring ability. Even during the optical fixing by the ultraviolet lamp 31, the microcomputer 50 monitors the measurement value of the second illuminance sensor 34 and keeps the illuminance of the ultraviolet rays applied to the recording area 10a constant, so that the entire surface of the recording area 10a is uniform. Light fixing is applied to the.

When the trailing edge of the recording area 10a passes the thermal head 18, the recording of the yellow image ends. The thermal head 18 rotates counterclockwise and separates from the color thermosensitive recording material 10. Then, when the rear end of the color thermosensitive recording material 10 reaches the position of the second conveying roller pair 15, the ultraviolet lamp 31 stops emitting light. Then, the drive motor 15b and the platen roller 17 are rotated in opposite directions by the transport motor 19. As a result, the color thermosensitive recording material 10 is conveyed in the opposite direction and returned to the position where the leading end of the color thermosensitive recording material 10 is nipped by the pair of conveying rollers 15.

Next, the ultraviolet lamp 41 of the magenta optical fixing device 40 starts to emit light. And the illuminance sensors 43, 4
4 measures the illuminance of the ultraviolet rays emitted from the ultraviolet lamp 41, and outputs the respective illuminance signals to the microcomputer 50.
Send to. Further, the sensor 45 for detecting the recording area also operates and sends the detection signal to the microcomputer 50.
The microcomputer 50 is a yellow light fixing device 30.
Similarly to the above, immediately after the ultraviolet lamp 41 starts emitting light, the ultraviolet lamp 41 is dimmed based on the illuminance signal from the first illuminance sensor 43.

A driving roller 15b is driven by the conveying motor 19.
When the platen roller 17 is rotated, the color thermosensitive recording material 10 is conveyed in the forward direction, and the magenta image printing process is started. When the tip of the recording area 10a reaches the position of the thermal head 18, the thermal head 1
8 moves to press the color thermosensitive recording material 10. The thermal head 18 thermally records a magenta image on the magenta thermosensitive coloring layer 62 line by line. At this time, since the optical fixing was properly performed by the yellow ultraviolet lamp 31, the magenta thermosensitive coloring layer 62 maintains its coloring ability in a good state, and the desired coloring density can be obtained.

Recording area 1 in which a magenta image is thermally recorded
0a is irradiated with ultraviolet rays of about 365 nm emitted from the magenta ultraviolet lamp 41 to perform fixing. The microcomputer 50 monitors the illuminance on the basis of the illuminance signal of the second illuminance sensor 45 even during the optical fixing by the ultraviolet lamp 41, and adjusts the light amount of the ultraviolet light irradiated onto the recording area 10a to be constant. ing. In magenta fixing, if insufficient fixing occurs, magenta develops color during thermal recording of a cyan image, but overfixing does not cause any trouble.
Therefore, it is preferable to adjust the amount of ultraviolet light to be a certain value or more.

After the recording of the magenta image, the ultraviolet lamp 41 stops emitting light when the rear end of the color thermosensitive recording material 10 reaches the position of the second conveying roller pair 15. Then, the driving motor 15 rotates the driving roller 15b and the platen roller 17 in the opposite directions to return the color thermosensitive recording material 10.

The driving roller 15b and the platen roller 17 are again rotated in the forward direction, the color thermosensitive recording material 10 is conveyed in the forward direction, and the cyan image printing process is started. The cyan image is printed by the thermal head 18 in the recording area 10a. Are recorded one line at a time. Cyan thermosensitive coloring layer 6
No. 1 requires about 80 thermal energy for heat-sensitive coloring.
Since it is not less than mJ / mm ² and no color is developed in a normal storage state, photofixability is not provided. Therefore, although the optical fixing of the cyan image is not necessary, the ultraviolet lamp 41 of the magenta optical fixing device 40 is turned on in order to eliminate the yellow tint of the color thermosensitive recording material 10.

When the thermal recording of the cyan image is completed, the thermally recorded color thermosensitive recording material 10 is conveyed to the paper discharge passage 16 side and discharged to a tray (not shown). Then, when the rear end of the color thermosensitive recording material 10 passes through the second conveying roller pair 15, the driving of the conveying motor 19 is stopped and the magenta ultraviolet lamp 41 is turned off.

In the above embodiment, the reflector is arranged on the back side of the ultraviolet lamp, but aluminum is vapor-deposited on the inner wall of the tube, which remains the surface facing the color thermosensitive recording material, to form the reflective layer. The formed ultraviolet lamp may be used. In this case, since only a small amount of light transmitted through the reflective layer is incident on the first illuminance sensor arranged on the back side of the ultraviolet lamp, the light emission intensity of the ultraviolet lamp is considered in consideration of the light transmittance of the reflective layer. Need to be adjusted.

Also, an example has been described in which a dedicated illuminance sensor is provided in the vicinity of each of the yellow and magenta ultraviolet lamps. However, the illuminance sensor is arranged between two ultraviolet lamps and emitted from each ultraviolet lamp. One illuminance sensor may also be used to measure the illuminance of ultraviolet rays.

Next, another embodiment will be described with reference to FIGS. 6 and 7. The yellow optical fixing device 70 includes a rod-shaped ultraviolet lamp 71, a reflector 72 that covers the back side of the ultraviolet lamp 71, and an illuminance sensor 73. The ultraviolet lamp 71 is arranged such that the central portion of the ultraviolet ray lamp 71, which has a stable light emission amount, faces the color thermosensitive recording material 10.
A width longer than the width of is used. Reflector 72
Has an opening 72b formed in the center of one side wall 72a and is arranged so as to cover the center of the ultraviolet lamp 71. The illuminance sensor 73 is arranged outside the opening 72b formed in the reflector 72, measures the illuminance of the ultraviolet light horizontally emitted from the ultraviolet lamp 71, and sends the illuminance signal to the microcomputer 75. Since the magenta optical fixing device 80 has the same structure, only the reference numeral is given.

The microcomputer 75 sends a lamp control signal corresponding to the illuminance signal from the illuminance sensor 73 to the driver 76 when the yellow image is optically fixed, and the ultraviolet lamp 7 receives the lamp control signal.
Dimming 1. Further, when the magenta image is optically fixed, a lamp control signal corresponding to the illuminance signal from the illuminance sensor 83 is sent to the driver 77, and the ultraviolet lamp 81 is dimmed.

According to this optical fixing device 70, the light emitted from the ultraviolet lamp 71 and reflected by the color thermosensitive recording material 10 is blocked by the side wall 72a of the reflector 72 and does not enter the illuminance sensor 73. Therefore, the illuminance sensor 73 can accurately measure the illuminance without being affected by the reflected light. Further, since the central portion of the ultraviolet lamp 71 facing the illuminance sensor 73 always has the maximum light emission amount irrespective of the tube wall temperature, by directly monitoring the illuminance of this central portion, the ultraviolet lamp 71 emits light. The strength can be adjusted and maintained at an appropriate value.

In each of the first and second embodiments, an example in which thermal recording and optical fixing are carried out while the color thermal recording material is conveyed back and forth has been described. However, the present invention is not limited to this. It is also applicable to a platen drum type color thermal printer in which is wound around the outer periphery of the platen drum and thermal recording and optical fixing are performed while the platen drum is rotating.

[0040]

As described above, according to the color thermal printer of the present invention, until the recording area of the color thermal recording material reaches the ultraviolet lamp, the illuminance from the central portion where the emission intensity becomes maximum is monitored. Since the ultraviolet lamp is dimmed, the ultraviolet illuminance at the central portion of the tube does not become excessive even when the temperature of the wall of the ultraviolet lamp is low and the emission intensity is not stable. As a result, over-fixing of the color thermosensitive recording material is prevented, and the coloring ability of the thermosensitive coloring layer that is the next layer is not impaired.

When the recording area of the color thermosensitive recording material faces the ultraviolet lamp, the light is adjusted based on the illuminance at the end of the ultraviolet lamp which does not face the color thermosensitive recording material. Since the light of unstable intensity reflected by the color thermosensitive recording material does not enter the second illuminance sensor for measuring, stable dimming can be performed. Moreover, since the temperature of the tube wall of the ultraviolet lamp rises during the transportation of the color thermal recording material and the emission intensity is stable over the entire area of the tube, the emission intensity in the area facing the color thermal recording material is adjusted to an appropriate value. ， Can be maintained.

Further, according to the invention of claim 2,
The illuminance sensor is placed outside the side wall of the reflector, and the illuminance of the ultraviolet light emitted horizontally from the ultraviolet lamp is measured, so the light reflected by the color thermosensitive recording material is blocked by the side wall of the reflector and enters the illuminance sensor. And the light control of the ultraviolet lamp can be performed accurately.
Moreover, since the illuminance from the central portion where the emission intensity of the ultraviolet lamp is maximum is constantly monitored and the light is adjusted, it is not affected by the change in the tube wall temperature of the ultraviolet lamp.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an optical fixing device.

FIG. 2 is a schematic diagram showing a configuration of a color thermal printer.

FIG. 3 is an explanatory diagram showing a recording area of a color thermosensitive recording material.

FIG. 4 is an explanatory diagram showing the relationship between the axial position of the ultraviolet lamp and the emission intensity, where (A) shows the case where the tube wall temperature of the ultraviolet lamp is low, and (B) shows the case where the tube wall temperature is high.

FIG. 5 is an explanatory diagram showing a layer structure of a color thermosensitive recording material.

FIG. 6 is a schematic diagram showing another configuration example of an optical fixing device.

FIG. 7 is a side view of a main part of the optical fixing device shown in FIG.

[Explanation of symbols]

10 color thermal recording materials 10a recording area 18 Thermal head 30, 40, 70, 80 Optical fixing device 31,41,71,81 UV lamp 32, 42, 72, 82 reflector 33,34,43,44,73,83 Illuminance sensor 35,45 Tip detection sensor 50,75 microcomputer

Claims (2)

(57) [Claims] 1. A color thermosensitive recording material in which a plurality of thermosensitive coloring layers are layered on a support, each thermosensitive coloring layer is thermally recorded by a thermal head while moving the color thermosensitive recording material, and the thermal recording is performed. In a color thermal printer that irradiates ultraviolet rays in a wavelength range peculiar to each thermosensitive coloring layer to the photo-fixing portion to fix it, a rod-shaped ultraviolet lamp arranged with both ends protruding from the side edges of the color thermal recording material, A first illuminance sensor for measuring the illuminance of ultraviolet rays emitted from the central portion in the axial direction of the ultraviolet lamp, a second illuminance sensor for measuring the illuminance of ultraviolet rays emitted from the end portion of the ultraviolet lamp, and an ultraviolet lamp When the recording area of the color thermosensitive recording material is not located on the front surface of the sheet, it depends on the measurement value of the first illuminance sensor, and when the recording area is located, the second Color thermal printer according to a controlling means for adjusting the emission intensity of the ultraviolet lamp in accordance with the measured value of the degree sensor. 2. A color thermosensitive recording material in which a plurality of thermosensitive coloring layers are layered on a support, each thermosensitive coloring layer is thermally recorded by a thermal head while moving the color thermosensitive recording material, and this thermosensitive recording layer is recorded. In a color thermal printer that irradiates UV rays in the wavelength range specific to each thermosensitive coloring layer to the photo-fixing area, a rod-shaped UV lamp that emits UV rays and the UV rays emitted behind the UV lamp are color-sensitive. A reflector reflecting to the recording material side, an opening formed in the reflector for passing ultraviolet rays emitted from a central portion in the axial direction of the ultraviolet lamp in a direction horizontal to the color thermosensitive recording material, and an opening arranged outside the opening. An illuminance sensor that measures the illuminance of the ultraviolet light emitted in the horizontal direction, and adjusts the emission intensity of the ultraviolet lamp according to the measurement value of the illuminance sensor. Color thermal printer according to a controlling means for.