JPH05104753A - Color thermal printer - Google Patents

Abstract

PURPOSE:To sufficiently bleach the unrecorded part of a thermal recording material without extending a printing time and making an apparatus large-sized and expensive. CONSTITUTION:A bleaching device 35 is attached on the way of a delivery path 28 in a freely detachable manner. A color thermal recording material 10 after the completion of thermal recording passes through the bleaching device 35 to be delivered to a tray. The color thermal recording material 10 entering the bleaching device 35 is fed while it goes round a UV lamp 36 and sufficiently irradiated with UV rays during this period. A residual diazonium salt compound is photolized by UV rays and a white frame having a light yellow color is finished white.

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 for thermally recording a video image or the like on a color thermal recording material.

[0002]

2. Description of the Related Art Thermal printers include thermal printers and thermal transfer printers. Of these, thermal printers tend to be widely used because they can directly thermally record an image on a thermal recording material. Most of them have a built-in monochrome thermal printer. Recently, for example, as described in JP-A-61-213169, a magenta thermosensitive coloring layer on a support,
A color thermosensitive recording material has been proposed in which a cyan thermosensitive coloring layer and a yellow thermosensitive coloring layer are sequentially laminated to enable direct thermal recording of a full-color image. This color thermosensitive recording material performs thermorecording in order from the thermosensitive coloring layer on the surface, but at the time of thermorecording on the next thermosensitive coloring layer, the thermosensitive coloring layer on which heat recording has been completed is prevented from being thermally recorded again. Therefore, after thermal recording, electromagnetic radiation in a wavelength range peculiar to each thermosensitive coloring layer is applied. Due to this electromagnetic radiation, the diazonium salt compound contained in the thermosensitive coloring layer is photodecomposed and the coloring ability is lost. Although this diazonium salt compound has a light yellow color, it is bleached to white when it is photofixed by irradiation with electromagnetic radiation.

The above-mentioned fixing is performed when the next layer is thermally recorded.
The color development due to this heat is performed to such an extent that it does not become a problem. In such fixing, electromagnetic rays are not sufficiently irradiated, so that unrecorded portions, for example, white frames and white portions of the background remain yellowish.

[0004]

In the case where the thermosensitive coloring layer has a three-layer structure, strong electromagnetic energy is used for fixing the second layer, which is the second layer from the top, and therefore the first layer, which is the first layer from the top, is used.
The layers can also be fixed at the same time. Therefore, the white frame or the like can be bleached by sufficiently fixing the second layer.

The sufficient fixing of the second layer can be achieved by using a fixing light source having a large light emission amount or by prolonging the fixing time. However, when a light source with a large light emission amount is used, there is a problem that the light source becomes large and expensive. On the other hand, if the fixing time is lengthened, there is a problem that the printing speed becomes slow.

In the present invention, the printing time becomes long,
An object of the present invention is to provide a color thermal printer capable of sufficiently bleaching an unrecorded portion of a thermal recording material without increasing the size and cost of the apparatus.

[0007]

SUMMARY OF THE INVENTION The color thermal printer of the present invention is provided with a bleaching light source in the paper discharge path for discharging the color thermal recording material for which thermal recording has been completed, so that the electromagnetic radiation is sufficiently colored. The recording material is irradiated.

[0008]

EXAMPLES In FIG. 1, a color thermosensitive recording material 10 is
A plurality of sheets are stacked in the cassette 11 and supplied to the color thermal printer. The cassette loading chamber of the color thermal printer is provided with a push-up member 12 which is spring-biased so as to push up the front end portion 10a of the color thermal recording material 10 through the lower opening 11a of the cassette 11, and is pushed up above it. Of the best color thermosensitive recording material 10
A paper feed roller 14 is provided which comes into contact with the surface a and rotates to feed the uppermost color thermosensitive recording material 10 to the paper feed path 13. A feed roller pair 15 is provided in the paper feed path 13 so that the color thermosensitive recording material 10 fed from the cassette 11 is fed toward the paper feed position of the platen drum 16.

The color thermosensitive recording material 10 has a tip portion 10a.
Is clamped by the clamp member 17 to the groove 1 of the platen drum 16.
It is pressed and fixed between 6a and 6a. The clamp member 17 is loosely fitted to the shaft 18 of the platen drum 16 through the elongated hole 17a, and the spring 19 allows the groove 16a to be formed.
Is urged in the direction of fitting with. Then, when the color thermosensitive recording material 10 is clamped and unclamped, the clamp member 17 is moved by the solenoid 20 in the direction of coming out of the groove 16a.

On the outer periphery of the platen drum 16, the thermal head 2 is provided at the thermal recording position of the color thermal recording material 10.
1, a yellow optical fixing device 22 and a magenta optical fixing device 23 are arranged on the downstream side thereof. Thermal head 21
, A large number of heating elements are arranged in a line in the main scanning direction, and each heating element generates heat energy according to the density of the pixel. The yellow optical fixing device 22 is composed of a rod-shaped ultraviolet lamp 24 having a light emission peak of about 420 nm and a reflector 25, and the magenta optical fixing device 23 is an ultraviolet lamp 26 having a light emission peak of about 365 nm and a reflector 2.
It consists of 7.

A pair of conveying rollers 30, 31, 32 for conveying the color thermosensitive recording material 10 toward a paper ejection tray 29 are provided in a paper ejection path 28 for ejecting the color thermosensitive recording material 10 on which all the thermal recording has been completed. , Guide plate 3 for changing the conveying direction
3, 34 are rotatably provided, and the guide plates 33, 3
A bleaching device 35 for bleaching the unrecorded portion of the color thermosensitive recording material 10 is detachably provided above the recording medium 4.

The bleacher 35 includes the ultraviolet lamps 24 and 2 described above.
6, a slightly larger UV lamp 36, and a plurality of conveying rollers 37a to 37f for rotating the color thermosensitive recording material 10 around the UV lamp 36 in order to irradiate the color thermosensitive recording material 10 with a sufficient amount of ultraviolet rays. The curved guide 38 and the curved guide 38 are housed inside a housing 39. The ultraviolet lamp 36 emits ultraviolet light in a wavelength region centered on about 365 nm, and the yellow thermosensitive coloring layer described later is not only 420 nm but 365 nm.
Since it is also photo-fixed by the ultraviolet rays, not only the magenta thermosensitive coloring layer but also the yellow thermosensitive coloring layer is fixed, and the entire color thermosensitive recording material 10 is sufficiently bleached.

When it is desired to give priority to speed over sufficient bleaching, such as in trial printing, the bleaching device 35 is removed from the paper discharge path 28 and the guide plate 3 is used.
3 and 34 are rotated to the positions shown by the dotted lines, and the color thermosensitive recording material 10 passes through the conveying roller pair 31 and the discharge tray 29.
To be transported toward. Further, on the platen drum 16 side of the paper discharge path 28, a separating claw 28 for guiding the rear end of the color thermosensitive recording material 10 to the paper discharge path 28 at the time of paper discharge.
a is formed.

FIG. 2 shows an example of a color thermosensitive recording material. The cyan thermosensitive coloring layer 4 is provided on the support 41.
2, magenta thermosensitive coloring layer 43, yellow thermosensitive coloring layer 4
4, the protective layer 45 is sequentially layered. These thermosensitive coloring layers 42 to 44 are layered from the surface in the order of thermal recording. For example, in the case of thermal recording in the order of magenta, yellow, and cyan, the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer. The positions of the layers are exchanged.

An opaque coated paper or a plastic film is used as the support 41, and a transparent plastic film is used when an OHP sheet is prepared. The cyan thermosensitive coloring layer 42 contains an electron-donating dye precursor and an electron-accepting compound as main components, and develops cyan when heated. Magenta thermosensitive coloring layer 4
No. 3 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. The magenta thermosensitive coloring layer 43 loses its coloring ability due to the photolysis of the diazonium salt compound when the magenta image is thermally recorded by the thermal head 21 and then irradiated with ultraviolet rays in the vicinity of 365 nm.

The yellow thermosensitive coloring layer 44 contains a diazonium salt compound having a maximum absorption wavelength of about 420 nm and a coupler which thermally reacts with the diazonium salt compound to develop yellow. The yellow thermosensitive coloring layer 44 also undergoes optical fixing when irradiated with near-ultraviolet rays in the vicinity of 420 nm and loses its coloring ability.
Therefore, the light is fixed even by near-ultraviolet rays of 365 nm, which has a higher energy than this. Since the magenta thermosensitive coloring layer 43 and the yellow thermosensitive coloring layer 44 contain a diazonium salt compound, the color thermosensitive recording material 10
Originally has a light yellow color.

When these thermosensitive coloring layers 43 and 44 are optically fixed, the unrecorded portion of the color thermosensitive recording material 10 changes from pale yellow to white, but the yellow optical fixing device 22 and the magenta optical fixing device 23. Cannot sufficiently perform bleaching because the amount of light emitted from the ultraviolet lamp is small. Therefore,
The color thermosensitive recording material 10 on which all the thermal recording has been completed is passed through the bleaching device 35 and irradiated with sufficient ultraviolet rays so that the unrecorded portion of the color thermosensitive recording material 10 is changed to a completely white color.

FIG. 3 shows the characteristics of the thermosensitive coloring layers 42 to 44. The thermal energy on the horizontal axis represents the thermal energy generated by the heating element of the thermal head 21, and the thermal energy of the yellow thermosensitive coloring layer 44 is the lowest and the thermal energy of the cyan thermosensitive coloring layer 42 is the highest.
The main cause of this difference in thermal energy is that the cyan thermosensitive coloring layer 42 must be heated via the yellow thermosensitive coloring layer 44 and the magenta thermosensitive coloring layer 43.

Next, the operation of the apparatus shown in FIG. 1 will be described with reference to FIG.
Will be described. Platen drum 16 when feeding
Has stopped at the paper feed position shown in FIG. Further, the solenoid 20 is energized and the clamp member 17 is pulled out from the groove 16a. The conveying roller pair 15 is a color thermosensitive recording material 1 supplied from the cassette 12 by the paper feeding roller 14.
0 is nipped and conveyed toward the platen drum 16.
At the same time that the leading end 10a of the color thermosensitive recording material 10 enters the groove 16a of the platen drum 16, the pair of conveying rollers 15 is temporarily stopped, and the energization of the solenoid 20 is stopped. As a result, the clamp member 17 is pulled back by the spring 19, so that the tip portion 10a is clamped by the clamp member 17. After this clamping, the platen drum 16 and the conveying roller pair 15 rotate,
The color thermosensitive recording material 10 is wound around the outer periphery of the platen drum 16.

As the platen drum 16 rotates, the end of the recording area of the color thermosensitive recording material 10 is moved to the thermal head 2.
When the number reaches 1, the yellow image is thermally recorded line by line by the thermal head 21. In the thermal recording of the yellow image, each heating element of the thermal head 21
Heat is generated at a temperature in consideration of the color development characteristics shown in FIG. The portion on which the yellow image is thermally recorded reaches the yellow optical fixing device 22 where optical fixing is performed. The near-ultraviolet light having a wavelength of about 420 nm is applied to the color thermosensitive recording material 10 by the yellow optical fixing device 22, and the magenta thermosensitive coloring layer 44 is fixed to the extent that yellow does not develop during the next thermal recording.

When the platen drum 16 makes one rotation and the recording area reaches the position of the thermal head 21 again, a magenta image is thermally recorded on the magenta thermosensitive coloring layer 43 line by line. At the time of thermal recording of the magenta image, the yellow optical fixing device 22 is turned off and instead the magenta optical fixing device 2 is turned off.
3 is turned on. As a result, the color thermosensitive recording material 10 is irradiated with ultraviolet rays having a wavelength of approximately 365 nm, and the cyan thermosensitive coloring layer 42 is optically fixed so that magenta does not develop color during thermal recording.

When the platen drum 16 rotates once, the magenta optical fixing device 23 is turned off. Then, since the color thermosensitive recording material 10 faces the thermal head 21, the cyan image is thermally recorded line by line by the thermal head 21. The cyan thermosensitive coloring layer 42 has a thermal energy of about 80 mJ / mm ² or more required for thermosensitive coloring, and therefore does not develop color under normal storage conditions.

In this way, the yellow image, the magenta image,
After the thermal recording of the cyan image is completed, the platen drum 16
UV lamp 36 of bleacher 35
Is lit. When the platen drum 16 is rotated in the reverse direction, the trailing end of the color thermosensitive recording material 10 is guided to the sheet discharge path 28 by the separation claw 28a and nipped by the pair of conveying rollers 30, the solenoid 20 is energized and the platen drum 16 is moved. Stop. Since the solenoid 20 moves the clamp member 17 against the spring 19, the clamp of the front end portion 10a of the color thermosensitive recording material 10 is released.

After releasing the clamp, the color thermosensitive recording material 1
Paper ejection of 0 is restarted. When the color thermosensitive recording material 10 comes into contact with the guide plate 33, the color thermosensitive recording material 10 is turned around and guided to the bleaching device 35. When the color thermosensitive recording material 10 enters the bleaching device 35, it is nipped by the conveying rollers 37a and 37b and conveyed toward the ultraviolet lamp 36.

The color thermosensitive recording material 10 is an ultraviolet lamp 3
When it reaches 6, it is conveyed while being slidably contacted with the peripheral surface of the ultraviolet lamp 36 by the conveying roller 37c and being rotated around the ultraviolet lamp 36 by the guide 38. During this period, the color thermosensitive recording material 10 is exposed to a large amount of ultraviolet rays and is sufficiently bleached.

The color thermosensitive recording material 10 comprises the conveying roller 3
When it reaches 7d, it is returned from the ultraviolet lamp 36 while being nipped by the transport rollers 37e and 37f and returned to the paper discharge path 28. The color thermosensitive recording material 10 is brought into contact with the guide plate 34 of the paper discharge path 28 to change its direction, and then, the conveying roller pair 32 is used.
The sheet is nipped and conveyed, and discharged to the sheet discharge tray 29.

The tip portion 10a of the color thermosensitive recording material 10 fixed by the clamp member 17 becomes a yellow band without being irradiated with the ultraviolet rays from the yellow light fixing device 22 and the magenta light fixing device 23. Although left, this yellow band is also sufficiently bleached by the bleacher 35.

In the embodiment described above, the bleaching device is detachably attached to the paper discharge path, but it may be fixed. Further, the conveying path in the bleaching device was formed so as to rotate the color thermosensitive recording material around the ultraviolet lamp so that a sufficient bleaching effect can be obtained without using a particularly large and powerful ultraviolet lamp. The present invention is not limited to this, and for example, a plurality of ultraviolet lamps may be arranged in parallel and passed between them. Further, the magenta optical fixing device 23 may be turned on during the thermal recording of cyan. This can reduce the bleaching time.

The above embodiment is a line printer for recording by moving the thermal head or the color thermosensitive recording material relatively in the sub-scanning direction, but the present invention is also applicable to a serial printer for two-dimensional relative movement for recording. Can be applied. This serial printer uses a thermal head in which heating elements are arranged in the main scanning direction and moves in the sub scanning direction during thermal recording, and the color thermosensitive recording material moves in the main scanning direction.

[0030]

As described in detail above, according to the color thermal printer of the present invention, the bleaching light source is provided in the paper discharge path for discharging the color thermal recording material, so that the electromagnetic radiation is sufficiently colored. Since the heat-sensitive recording material is irradiated, the unrecorded portion of the color heat-sensitive recording material can be sufficiently bleached without prolonging the printing time and increasing the size and cost of the apparatus.

[Brief description of drawings]

FIG. 1 is a schematic view of a color thermal printer showing a state in which a color thermal recording material is bleached.

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

FIG. 3 is a graph showing color forming characteristics of a color thermosensitive recording material.

FIG. 4 is a schematic view showing a paper feeding state of a color thermosensitive recording material.

[Explanation of symbols]

 10 Color Thermal Recording Material 16 Platen Drum 17 Clamping Member 21 Thermal Head 22 Yellow Optical Fixing Device 23 Magenta Optical Fixing Device 28 Paper Ejection Path 35 Bleaching Device 36 UV Lamp

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B41M 5/26 8305-2H B41M 5/26 S

Claims (1)

[Claims] 1. A color thermal printer in which a thermosensitive coloring layer of a color thermosensitive recording material is thermally recorded and then fixed by irradiating an electromagnetic ray from an optical fixing device for bleaching in a discharge path of the color thermosensitive recording material. A color thermal printer comprising a light source, wherein the color thermal recording material is irradiated with electromagnetic rays by a bleaching light source while discharging the thermally recorded color thermal recording material to bleach an unrecorded portion.