JP3522889B2 - 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, and more particularly to an improved arrangement of a capstan roller belt for conveying color thermal recording paper and a fixing UV lamp.

[0002]

2. Description of the Related Art A color thermal printer is provided with a capstan roller and a pinch roller for nipping and transporting a color thermal recording paper, and a thermal head for pressing and heating the color thermal recording paper being transported to develop a color. ing. On this color thermosensitive recording paper, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer are sequentially laminated,
A full-color image is recorded in three-color frame sequence.

In the color thermosensitive recording paper, the upper thermosensitive coloring layer has higher thermal sensitivity and develops color with a small amount of heat energy. Therefore, the thermal head adjusts the thermal energy applied to the color thermosensitive recording paper to selectively develop the three types of thermosensitive coloring layers. Further, in the case of recording the lower thermosensitive coloring layer, ultraviolet rays in a wavelength range peculiar to the recorded thermosensitive coloring layer on the upper layer are irradiated to perform optical fixing.

When the color thermosensitive recording paper has a three-layer structure,
Two types of ultraviolet lamps are used to fix the thermosensitive coloring layers of the uppermost layer and the intermediate layer, respectively. These ultraviolet lamps are arranged on the opposite side of the thermal head centering on the capstan roller and irradiate the color thermosensitive recording paper with ultraviolet rays.

As the ultraviolet lamp, a rod-shaped lamp similar to a fluorescent lamp is used and is arranged in parallel with the capstan roller. Further, the ultraviolet lamp is arranged so that the central portion where the amount of emitted light is substantially constant faces the color thermosensitive recording paper, and both ends protrude from both sides of the conveying path of the color thermosensitive recording paper.

[0006]

The capstan roller is rotated by a motor via a belt, which must be installed avoiding the ends of the UV lamp. Therefore, the freedom of motor placement is restricted,
For example, it can be arranged only above or below the capstan roller, which hinders the miniaturization of the device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color thermal printer in which the degree of freedom in motor arrangement is increased and the size of the apparatus can be reduced.

[0008]

In order to achieve the above-mentioned object, a color thermal printer according to claim 1 , wherein
Ultraviolet rays are facing the transport path of the thermal recording paper and to the transport path.
While arranging the motor on the same side as the lamp,
The end of the ultraviolet lamp is inserted into a belt for transmitting the rotation of the motor to the capstan roller.

In the color thermal printer according to claim 2,
The belt has a triangular shape by providing a tension pulley for keeping the belt tension constant.

In the color thermal printer of the present invention, since the belt is arranged so as to surround the end of the ultraviolet lamp, the position of the motor is lowered and the apparatus can be made compact. Further, by providing a tension pulley for preventing the slack of the belt and widening the space inside the belt, it becomes easy to dispose the ultraviolet lamp, and it is possible to use an ultraviolet lamp having a large diameter and a large amount of light emission.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, color thermosensitive recording paper 4
Is nipped by the capstan roller 8 and the nip roller 9 and reciprocated along a substantially horizontal conveyance path.
A thermal head 7 and a platen roller 5 are arranged on one side of the capstan roller 8, and two rod-shaped ultraviolet lamps 10 and 11 are arranged on the opposite side. As is well known, the thermal head 7 has a large number of heating elements formed in a line. This thermal head 7
Causes the color thermosensitive recording paper 4 being conveyed by the capstan roller 8 and the nip roller 9 to be pressed against the platen roller 5 to heat and develop color.

As is well known, the color thermosensitive recording paper 4 comprises a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer and a yellow thermosensitive coloring layer on a support, and a yellow thermosensitive coloring layer serving as the uppermost layer. Has the lowest thermal sensitivity, and the lowermost cyan thermosensitive coloring layer has the highest thermal sensitivity. The yellow thermosensitive coloring layer was emitted from the ultraviolet lamp 10 after thermal recording.
It is fixed by being irradiated with ultraviolet rays in the wavelength range of 20 nm. The magenta thermosensitive coloring layer is fixed by ultraviolet rays emitted from the ultraviolet lamp 11 in the wavelength region of 365 nm after thermal recording.
It should be noted that the cyan thermosensitive coloring layer is not provided with the fixing property by ultraviolet rays. Further, the order of the thermosensitive coloring layers may be exchanged.

The ultraviolet lamps 10 and 11 have a reflective film formed inside the ultraviolet lamps except for the openings. The openings are arranged so as to face the color thermosensitive recording paper 4, and the color thermosensitive recording passes below the thermosensitive recording paper 4. The paper 4 is irradiated with ultraviolet rays. Although the amount of light emitted from the ultraviolet lamps 10 and 11 is substantially constant in the central portion thereof, the amount of light emitted from both end portions decreases toward the ends. Therefore, as the ultraviolet lamps 10 and 11, ones longer than the width of the color thermosensitive recording paper 4 are used, and both ends thereof are arranged so as to protrude from both sides of the color thermosensitive recording paper 4.

The pulse motor 13 is used for the color thermosensitive recording paper 4
It is arranged beside the ultraviolet lamp 11 above the transport path. The rotation of the pulse motor 13 is transmitted to the gear 25 via the gear 13a fixed to the output shaft and the intermediate gear 24. The drive pulley 22 is provided coaxially with the gear 25. The driven pulley 21 is fixed to the shaft 8a of the capstan roller 8. These pulleys 22, 2
A timing belt 23 having teeth is hung on 1, and the rotation of the pulse motor 13 is transmitted to the capstan roller 8. The timing belt 23 is arranged so as to surround the ultraviolet lamps 10 and 11 in order to avoid hitting the ends 10a and 11a. By arranging the timing belt 23 in this way, it becomes possible to arrange the pulse motor 13 so as to be close to the conveyance path of the color thermosensitive recording paper 4, thereby reducing the height of the entire apparatus and making it compact. Can be planned.

Next, the operation of the above embodiment will be described. During printing, the pulse motor 13 rotates clockwise, and the driving force thereof is transmitted to the drive pulley 22 via the gears 24 and 25. When the drive pulley 22 rotates clockwise, the driven pulley 21 rotates via the timing belt 23, and the color thermosensitive recording paper 4 nipped between the capstan roller 8 and the nip roller 9 is conveyed in the arrow direction.
When the color thermosensitive recording paper 4 passes through the thermal head 7, a yellow image is thermally recorded line by line by the thermal head 7. The portion on which the yellow image is thermally recorded is irradiated with ultraviolet rays of about 420 nm from the ultraviolet lamp 10 and fixed.

When the optical fixing of the portion where the yellow image is thermally recorded is completed, the pulse motor 13 rotates counterclockwise to convey the color thermosensitive recording paper 4 in the direction opposite to the arrow direction,
The color thermosensitive recording paper 4 is returned to the predetermined position. When the color thermal recording paper 4 is returned, the thermal head is retracted from the transport path. Next, the pulse motor 13 is rotated again in the clockwise direction to convey the color thermosensitive recording paper 4 in the arrow direction. During the transportation, the magenta image is thermally recorded on the color thermosensitive recording paper 4 line by line by the thermal head 7. The portion on which the magenta image is thermally recorded is irradiated with ultraviolet rays of about 365 nm from the ultraviolet lamp 11 to be fixed.

After the fixing, the pulse motor 13 rotates counterclockwise to return the color thermosensitive recording paper 4 to the predetermined position again. Next, the color thermosensitive recording paper 4 is conveyed again in the direction of the arrow, and the cyan image is thermally recorded line by line by the thermal head 7. By recording the three color planes sequentially in this manner, a full-color image is formed on the color thermosensitive recording paper 4.

When an ultraviolet lamp having a large diameter is used to increase the amount of emitted light, the ultraviolet lamp may come into contact with the timing belt. Further, due to the layout of each mechanism, it may be necessary to slightly shift the position of the pulse motor 13. In such a case, as shown in FIG. 3, it is preferable to use the tension pulley 31 urged by the spring 30 and arrange the timing belt 32 in a triangular shape.

The drive pulley 22 may be integral with or separate from the gear 25, and similarly, the driven pulley 21 may be integral with or separate from the capstan roller 8. In addition, the drive pulley 22
May be fixed to the rotation shaft of the pulse motor 13. Further, instead of the timing belt 23, a V belt or a flat belt may be used. Furthermore, the number and type of ultraviolet lamps can be increased or decreased according to the amount of fixing light and the type of thermosensitive coloring layer.

[0020]

As described above in detail, in the present invention, the timing belt is arranged so as to surround the end portion of the fixing lamp. Therefore, it is not necessary to dispose the timing belt away from the fixing lamp. The space can be efficiently used, and the printer can be downsized.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a color thermal printer of the present invention.

FIG. 2 is a plan view showing a main part of the color thermal printer shown in FIG.

FIG. 3 is a front view of essential parts showing an embodiment in which a timing belt is arranged in a triangle by using a tension pulley.

[Explanation of symbols]

4 color thermal recording paper 7 thermal head 8 capstan rollers 9 Nip rollers 10,11 UV lamp 10a, 11a ends 13 pulse motor 21,22 pulley 23, 32 Timing belt 30 springs 31 Tension pulley

Claims (2)

(57) [Claims] 1. A capstan roller and a pinch roller for nipping and conveying color thermosensitive recording paper, a thermal head for heating the color thermosensitive recording paper being conveyed to record an image, and a capstan roller arranged in parallel. in color thermal printer having been irradiated with ultraviolet light the recording paper and the ultraviolet lamp for optical fixation, to face the transport path of the recording paper, and the conveying path to
If the motor is placed on the same side as the UV lamp,
Together so as to surround the end of the ultraviolet lamp, the color thermal printer, characterized in that a belt for transmitting the rotation of the motor to the capstan roller. 2. The color thermal printer according to claim 1, wherein a tension pulley for keeping the tension of the belt constant is provided, and the belt has a triangular shape.