JP2003341115A - Color thermal printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance cooling capacity of a fixing unit. <P>SOLUTION: A lamp house 29 for housing a UV-lamp 28 comprises a house body 31 having an opening 31a for radiating UV-rays in the lower surface, and a translucent plate 32 made of a transparent material, e.g. glass or acryl, and being fitted in the radiation opening 31a. Two air supply openings 31b are made at positions on the upper surface of the house body 31 facing the base part 28a of the UV-lamp 28 and air supply fans 35 are disposed thereon. An exhaust opening 31c is made in the center of the upper surface of the house body 31 and an exhaust fan 37 is disposed thereon. The air supply fans 35 supply air into the lamp house 29 and the exhaust fan 37 discharges heat from the UV-lamp 28 and the translucent plate 32 through the exhaust opening 31c. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color thermal printer, and more particularly to a color thermal printer that cools a fixing lamp.

[0002]

2. Description of the Related Art In a color thermal printer in which a thermal head is pressed against a color thermosensitive recording paper having a plurality of thermosensitive coloring layers for thermal recording, an ultraviolet lamp is used for fixing the thermosensitive coloring layers. This ultraviolet lamp is a straight-tube fluorescent lamp having caps at both ends, and the amount of light emission decreases if the temperature of the tube wall rises too much. Therefore, in the color thermal printer, the temperature control of the ultraviolet lamp is required.

In order to cool an ultraviolet lamp, Japanese Patent Laid-Open No. Hei 6-1994
-64281, JP-A-6-239022, JP-A-7
Inventions such as No. 61004 and JP-A No. 2000-158685 have been made. In these inventions, in order to prevent the temperature of the tube wall of the ultraviolet lamp from decreasing and the amount of light emission from decreasing, air is blown by a fan along the longitudinal direction of the ultraviolet lamp to cool it.

[0004]

According to the cooling method of the present invention, the tube wall temperature of the ultraviolet lamp does not rise even when several tens of sheets of color thermosensitive recording paper are continuously printed. However, in a color thermal printer that uses a long color thermal recording paper, if several hundreds of prints are continuously printed, the temperature of the ultraviolet lamp tube wall is so high that color printing of the color thermal recording paper occurs and a jam occurs. Could rise.

The present invention is intended to solve the above problems, and an object thereof is to improve the cooling capacity of an ultraviolet lamp.

[0006]

In order to solve the above problems, in the image forming apparatus of the present invention, the entire circumference of the fixing lamp is covered with a lamp house to shield light, and the surface of the lamp house with respect to the color thermosensitive recording paper is covered. A light-transmitting plate that transmits fixing light was attached to the lamp house, and an air supply port and an exhaust port were formed in this lamp house, and air was blown from the air supply port with an air supply fan, and hot air was exhausted from the exhaust port. It is a thing.

Further, in order to enhance the effect of discharging hot air from the exhaust port, an exhaust fan for sucking air in the lamp house may be arranged near the exhaust port. Further, it is possible to cool the transparent plate by sending air to the transparent plate.

[0008]

FIG. 1 is a schematic diagram showing the structure of a color thermal printer embodying the present invention. In this color thermal printer 2, a recording paper roll 4 obtained by winding a long color thermal recording paper 3 in a roll shape is used as a recording medium. The recording paper roll 4 is provided with a light-shielding paper feed magazine 5
And the paper feed magazine 5 is set in the paper feed unit 7 provided on the front surface of the housing 6 of the color thermal printer 2.

A feed roller pair 9 for feeding and rewinding the color thermosensitive recording paper 3 is incorporated in the paper feeding magazine 5. The feed roller pair 9 includes a capstan roller and a pinch roller. When the paper feed magazine 5 is set in the paper feed unit 7, the capstan roller is electrically or mechanically connected to the color thermal printer 2 and its drive is controlled. The color thermosensitive recording paper 3 delivered from the paper supply magazine 5 is delivered into a substantially U-shaped conveyance path provided in the housing 6.

As is well known, the color thermosensitive recording paper 3 has a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer and a yellow thermosensitive coloring layer which are sequentially formed on a support. The yellow thermosensitive coloring layer, which is the uppermost layer, has the highest heat sensitivity and develops yellow with a small amount of heat energy. The cyan thermosensitive coloring layer, which is the lowermost layer, has the lowest thermal sensitivity and develops cyan with a large amount of heat energy. The yellow thermosensitive coloring layer has a thickness of 420 nm.
When it is irradiated with the near-ultraviolet rays, the coloring ability disappears.
The magenta thermosensitive coloring layer develops magenta with heat energy which is about the intermediate level between the yellow thermosensitive coloring layer and the cyan thermosensitive coloring layer, and loses its coloring ability when irradiated with ultraviolet rays of 365 nm. The color thermosensitive recording paper 2 may be provided with a black thermosensitive coloring layer to have a four-layer structure.

In the conveying path of the color thermosensitive recording paper 3, printing portions 11 to 13 for yellow, magenta and cyan are arranged at a predetermined interval. Printing part 1 for yellow
Reference numeral 1 denotes a pair of conveying rollers 15 for conveying the color thermosensitive recording paper 3 in the sheet feeding direction, a thermal head 16 for pressing the color thermosensitive recording paper 3 to develop a thermosensitive coloring layer, and a thermal head 16 together with the color thermosensitive recording paper 3 Platen roller 17 that holds the sheet and rotates as the color thermosensitive recording paper 3 is conveyed.
Consists of.

The conveying roller pair 15 is composed of a capstan roller which is rotationally driven by a stepping motor, and a pinch roller which presses the capstan roller to sandwich the color thermosensitive recording paper 3 therebetween.

Each of the thermal heads 16 has a heating element array in which a large number of heating elements are arranged in a line, and these heating element arrays are brought into pressure contact with the color thermosensitive recording paper 3 to generate heat, thereby performing color thermosensitive recording. The yellow thermosensitive coloring layer of the paper 3 is colored.

Since the magenta printing unit 12 and the cyan printing unit 13 have the same structure as the yellow printing unit 11, detailed description thereof will be omitted.

A yellow fixing device 25 is arranged between the yellow printing portion 11 and the magenta printing portion 12. Further, the magenta printing unit 12 and the cyan printing unit 13
A magenta fixing device 26 is disposed between the two.
The fixing device 25 for yellow covers a plurality of ultraviolet lamps 28 that emit near-ultraviolet rays having an emission peak of 420 nm to fix the yellow thermosensitive coloring layer of the color thermosensitive recording paper 3 and the entire circumference of these ultraviolet lamps 28. It is composed of a substantially box-shaped lamp house 29 that shields light.

As shown in FIGS. 2 and 3, the lamp house 29 is formed of an aluminum plate or the like in a substantially box shape, and the house body 3 has a radiation opening 31a for radiating ultraviolet rays on the lower surface thereof.
1, a transparent plate 32 formed of a transparent material such as glass or acrylic, fitted into the radiation opening 31a to seal the house main body 31 and also serve as a guide for the color thermosensitive recording paper 3, and an ultraviolet lamp 28. And a plurality of sockets 33 to which the base portions 28a of the above are connected.

If the tube wall temperature rises too much, the amount of light emitted from the ultraviolet lamp 28 will decrease. Further, if the temperature of the light-transmissive plate 32 rises too much, the color thermosensitive recording paper 3 that comes into contact with the light-transmissive plate 32 develops color, or the color thermosensitive recording paper 3 changes its color.
Sometimes it sticks to 2.

On the upper surface of the house body 31, the ultraviolet lamp 2
The two air inlets 3 are provided at the position facing the mouthpiece portion 28a of 8
1b is formed. An exhaust port 31c is formed in the center of the upper surface of the house body 31. Thereby, the lamp house 29 acts like a duct.

Above the air supply port 31b of the house main body 31, there are arranged air supply fans 35 for blowing air toward the air supply port. An exhaust fan 37 is attached inside the house body 31 so as to face the exhaust port 31c. Axial fans are used as the air supply fan 35 and the exhaust fan 37.

The magenta fixing device 26 has an emission peak of 3
The yellow fixing device 25 has the same configuration as that of the yellow fixing device 25 except that the ultraviolet lamp 40 that emits 65 nm ultraviolet light is used.

A paper discharge port 45 for discharging the printed color thermosensitive recording paper 3 is provided on the upper part of the front surface of the casing 6 at the most downstream side in the paper feeding direction of the conveying path. A cutter 46, which cuts the long color thermosensitive recording paper 3 at a predetermined position into a sheet shape, is arranged at the back of the paper discharge port 45.

Next, the operation of the above embodiment will be described. As shown in FIG. 1, when a print start operation is performed in the color thermal printer 2, the yellow fixing device 25
The air supply fan 35 and the exhaust fan 37, and the air supply fan 42 and the exhaust fan 43 of the magenta fixing device 26 start to rotate. The timing for starting the rotation of each fan is
The temperature of the color thermal printer 2 may be turned on, or the temperatures of the yellow fixing device 25 and the magenta fixing device 26 may be measured, and rotation may be started when the temperatures reach a specified value or higher.

As shown in FIGS. 2 and 3, the two air supply fans 35 blow air into the lamp house 29 through the air supply port 31b. The airflow generated by the air supply fan 35 cools the base portion 28a of the ultraviolet lamp 28.
Further, it flows toward the center of the lamp house 29 while flowing on the transparent plate 32 to cool the transparent plate 32 and the tube wall of the ultraviolet lamp 28. Then, the exhaust fan 37 releases the heat from the exhaust port 31c together with the heat of the ultraviolet lamp 28.

In the magenta fixing device 26, as in the yellow fixing device 25, the air supply fan 42 and the exhaust fan 43 act to cool the ultraviolet lamp 40 and the transparent plate to release heat.

The feed roller pair 9 pulls out the color thermosensitive recording paper 2 from the recording paper roll 4 and conveys it toward the conveying path of the color thermosensitive printer 2. Printing part 11 for yellow
The color thermosensitive recording paper 3 which has arrived at is conveyed by the conveying roller pair 15 at a constant speed in the paper feeding direction. Then, it is sandwiched between the thermal head 16 and the platen roller 17, and a yellow image is printed on the yellow thermosensitive coloring layer.

The color thermosensitive recording paper 3 on which a yellow image is printed has a light emission peak of 4 due to the fixing device 25 for yellow.
Irradiation with near-ultraviolet rays of 20 nm fixes the yellow thermosensitive coloring layer. The fixing device 25 for yellow has an air supply fan 35.
Also, since it is cooled by the exhaust fan 37, the light emission amount does not decrease. Further, since the translucent plate 32 is also cooled, the portion of the color thermosensitive recording paper 3 in contact with the translucent plate 32 does not develop color, and the color thermosensitive recording paper 3 does not stick to the translucent plate 32.

The color thermosensitive recording paper 3 to which the yellow thermosensitive coloring layer is fixed is sent to the magenta printing section 12.
In the magenta printing unit 12, the color thermosensitive recording paper 3 is conveyed in the paper feeding direction by the conveying roller pair 18, and an image is printed on the magenta thermosensitive coloring layer by the thermal head 19.

The color thermosensitive recording paper 3 on which a magenta image is printed has a light emission peak of 3 due to the magenta fixing device 26.
The magenta thermosensitive coloring layer is fixed by irradiating with a 65 nm ultraviolet ray. Since the magenta fixing device 26 is cooled by the air supply fan 42 and the exhaust fan 43, the light emission amount does not decrease. Further, since the light-transmitting plate of the magenta fixing device 26 is also cooled, the color heat-sensitive recording paper 3 does not develop color and the color heat-sensitive recording paper 3 does not stick to the light-transmitting plate.

The color thermosensitive recording paper 3 on which the magenta thermosensitive coloring layer is fixed is sent to the cyan printing portion 13 and an image is printed on the cyan thermosensitive coloring layer by the thermal head 22. The color thermosensitive recording paper 3 on which the cyan image has been printed is cut by the cutter 46 into a sheet-like color print, and sent out of the housing 6 through the paper discharge port 45.

In the above embodiment, the exhaust fan 37
Although it has been installed in the lamp house 29, it may be arranged above the lamp house 29 as in the case of the air supply fan 35, as shown in FIG.

Further, as shown in the fixing device 50 of FIG. 5, an air supply port 52a is formed on the upper surface of the lamp house 52 at a position facing one base portion 51a of the ultraviolet lamp 51, and the other base portion 51b is formed. An exhaust port 52b is formed at a position facing each other, and an air supply fan 53 and an exhaust fan 54 are provided above them.
And may be installed.

Further, as shown in the fixing device 60 of FIG. 6, exhaust ports 64 and 65 may be provided on both sides of the transparent plate 63 of the lamp house 62 that covers the ultraviolet lamp 61. According to this, since the air easily flows on the transparent plate 63, the cooling efficiency of the transparent plate 63 can be improved. Further, since the air flowing out from the exhaust ports 64 and 65 flows between the transparent plate 63 and the color thermosensitive recording paper, the transparent plate 63 can be cooled from both sides.

Further, as shown in the fixing device 70 in FIG. 7, an air supply port 73 and an air supply fan 74 are provided in the center of the lamp house 71 for blowing air toward the transparent plate 72 for cooling. Exhaust may be performed through exhaust ports 75 and 76 arranged on both sides of the optical plate 72. According to this embodiment, since the transparent plate 72 can be directly cooled by the intake fan 74, it is possible to reliably prevent the coloring or sticking of the color thermosensitive recording paper due to the contact with the transparent plate 72.

Further, in each of the above embodiments, the exhaust fan is installed near the exhaust port, but the exhaust fan may be omitted if an appropriate air flow can be formed only by the air supply fan. Further, although the axial fan is used as the air supply fan and the exhaust fan, a sirocco fan, a cross flow fan or the like may be used.

Furthermore, in each of the above-described embodiments, the fixing lamp of the color thermal printer has been described as an example, but it can be used for cooling other heat-generating components such as a thermal head. It can also be used to cool heat-generating components of printers other than color thermal printers and other devices.

[0036]

As described above, according to the color thermal printer of the present invention, since the lamp house acts as a duct, the fixing lamp can be effectively cooled. In addition, it is possible to improve the cooling efficiency of the translucent plate to improve the print quality and reduce the trouble of conveying the recording paper.

[Brief description of drawings]

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

FIG. 2 is an external perspective view of a fixing device for yellow.

FIG. 3 is a cross-sectional view of a main part of a yellow fixing device.

FIG. 4 is a cross-sectional view of a main part of a yellow fixing device in which an exhaust fan is arranged outside a lamp house.

FIG. 5 is a cross-sectional view of a main part of a yellow fixing device in which an air supply port and an exhaust port are arranged at both ends of a lamp house.

FIG. 6 is a cross-sectional view of a main part of a yellow fixing device in which exhaust ports are arranged on both sides of a transparent plate.

FIG. 7 is a cross-sectional view of a main part of a yellow fixing device in which an air supply port and an air supply fan are arranged at positions facing a translucent plate.

[Explanation of symbols]

2 color thermal printer 3 color thermal recording paper 6 housing 11-13 Printing department 25 Yellow fixing device 26 Magenta fuser 29,41 Lamp House 31b Air supply port 31c exhaust port 32 translucent plate 35, 42 air supply fan 37,43 exhaust fan

Claims (3)

[Claims] 1. A color thermosensitive recording paper having a plurality of thermosensitive coloring layers provided on a support, and a thermal head are moved relative to each other to perform thermal recording on each thermosensitive coloring layer, and at the same time, the thermosensitive recording is completed. In a color thermal printer that irradiates fixing light to the color forming layer so that it does not develop color, a transparent plate that covers the entire circumference of the fixing lamp to block light and transmits the fixing light to the surface of the color thermosensitive recording paper. The lamp house, at least one air supply port formed in the lamp house, an air supply fan disposed near the air supply port for blowing air into the lamp house, and at least one in the lamp house. A color thermal printer, characterized in that it is provided with an exhaust port for discharging the air flowing through the lamp house. 2. The color thermal printer according to claim 1, wherein an exhaust fan for sucking air in the lamp house is provided near the exhaust port. 3. The color thermal printer according to claim 1, wherein an air supply port is arranged at a position facing the translucent plate, and air is blown to the translucent plate to cool it.