JP2003054017A - Photofixing system for thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a photofixing time. SOLUTION: A UV-lamp 23 performs photofixing by irradiating a recording sheet 3 with UV-rays. The UV-lamp 23 comprises a pair of a base 32 and a glass tube 31. The glass tube 31 is shaped by bending a rod-like tube having circular cross-section a plurality of times in order to enlarge the facing area A1 of the glass tube 31 and the recording sheet 3. Consequently, the recording sheet 3 can be irradiated with a large quantity of UV-rays at a high intensity. Linear part 31a of the glass tube 31 is arranged along the widthwise direction of the recording sheet 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fixing device for a thermal printer, which irradiates a thermal recording material with ultraviolet rays to perform optical fixing.

[0002]

2. Description of the Related Art At least three types of thermosensitive coloring layers such as a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and
There is known a thermal printer that prints a full-color image using a color thermosensitive recording paper (hereinafter referred to as a recording paper) in which a yellow thermosensitive coloring layer is layered in order. In this printer, the thermal head is pressed against the recording paper at the time of printing, the yellow image is thermally recorded on the yellow thermosensitive coloring layer having the highest thermal sensitivity, and immediately after that, the yellow thermosensitive coloring layer is irradiated with ultraviolet rays to be optically fixed. Next, a magenta image is thermally recorded on the magenta thermosensitive coloring layer, and then ultraviolet rays are irradiated to fix the magenta image. Finally, a cyan image is thermally recorded on the cyan thermosensitive coloring layer to obtain a full-color image.

The thermal printer is provided with a pair of conveying rollers for conveying the recording paper, a thermal head, and an optical fixing device having an ultraviolet lamp for irradiating ultraviolet rays, which are arranged in the paper feeding / discharging direction (sub-scanning direction). Direction). In the printing process, the recording paper is conveyed in the paper feeding / discharging direction by the conveying roller pair, and during this conveyance, thermal recording is performed line by line in the width direction (main scanning direction) of the recording paper.

As the optical fixing device, a straight tube type ultraviolet lamp having a circular cross section is generally used, and the straight tube is arranged in the longitudinal direction along the main scanning direction. A reflector is provided around the ultraviolet lamp. This reflector reflects the ultraviolet light, which is not directly irradiated from the ultraviolet lamp toward the recording paper, toward the recording paper. Since the straight tube type ultraviolet lamp is easy to manufacture, it is generally used because of the demand for cost reduction. Further, since the cross section is circular, the structural strength is relatively high.

However, this straight tube type ultraviolet lamp has a small amount of high intensity ultraviolet rays which are directly irradiated from its light emitting surface toward the light receiving surface of the recording paper. That is, as shown in FIG. 4, an area A0 (hereinafter referred to as an effective light emitting area) where the light emitting surface of the ultraviolet lamp 51 and the light receiving surface of the recording paper 3 face each other is very small. The amount of light received by the recording paper 3 is proportional to the intensity of ultraviolet rays and inversely proportional to the conveying speed. Therefore, if the amount of high-intensity ultraviolet rays increases, the conveying speed can be increased and the optical fixing time can be shortened. it can.

Therefore, in the optical fixing device disclosed in Japanese Patent Laid-Open No. 5-155135, the effective light emitting area is widened by forming the ultraviolet lamp into a flat shape extending in the sub-scanning direction. Further, in the optical fixing device disclosed in Japanese Patent Laid-Open No. 2000-177155, the effective light emitting area is expanded by using a panel-shaped plasma display as a light source of ultraviolet rays. This plasma display is composed of a pair of glass substrates on which a cathode and an anode are formed, and a spacer for ensuring a certain space between these glass substrates.

[0007]

However, since it is difficult to mold glass into a flat shape, the manufacturing cost is high. Further, making the glass flat has some problems in terms of strength. On the other hand, the plasma display has a complicated structure and is expensive to manufacture. Further, the plasma display has a problem that a large amount of heat is generated and the luminous efficiency, which is a ratio of the amount of light emission to the power consumption, is low.

In order to solve the above problems, it is an object of an optical fixing device of a thermal printer of the present invention to provide an optical fixing device that can reduce fixing time at low cost.

[0009]

In order to achieve the above object, an optical fixing device of a thermal printer of the present invention is an optical fixing device of a thermal printer for irradiating an ultraviolet ray to a heat-recorded thermosensitive recording material to perform optical fixing. In the above, using an ultraviolet lamp composed of a pair of bases for supplying power and a glass tube, the glass tube is bent a plurality of times to widen the area where the glass tube and the thermal recording material face each other. Characterize.

The cross-sectional shape of the glass tube is preferably circular. Further, it is preferable that a straight line portion between the plurality of bent portions of the glass tube is arranged along the width direction of the thermosensitive recording material. The length of the linear portion is preferably substantially the same as the width of the heat-sensitive recording material.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The thermal printer 2 shown in FIG.
Performs thermal recording and fixing of a full-color image while reciprocating the recording paper 3 in the forward direction and in the reverse direction. Chart paper 3
As is well known, a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, and a yellow thermosensitive coloring layer are sequentially formed on a support. The yellow thermosensitive coloring layer, which is the uppermost layer, has high thermal 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 when a large amount of heat energy is applied. Further, the yellow thermosensitive coloring layer loses its coloring ability when irradiated with near-ultraviolet rays of 420 nm. 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 thermal printer 2 includes a thermal head 6 for heating each thermosensitive coloring layer to develop a color, and a platen roller 7 for supporting the recording paper 3 facing the thermal head 6.
And a conveyance roller pair 12 for conveying the recording paper 3 and an optical fixing device 14.

The pair of transport rollers 12 are used to feed the recording paper 3 that has been fed.
Nip and convey in the sub-scanning direction. During this conveyance, the recording paper 3 passes through the thermal head 6 and the optical fixing device 14, and the printing process is performed. The recording paper 3 for which the printing process has been completed is cut into a predetermined size by a cutter (not shown) and discharged.

The thermal head 6 is provided with a heating element array 6a in which a large number of heating elements are arranged in a line. The heating element array 6a is arranged along the width direction (main scanning direction) of the recording paper 3. Thermal recording is performed line by line along the main scanning direction.

The optical fixing device 14 emits near-ultraviolet rays of 420 nm, emits near-ultraviolet rays of 365 nm and ultraviolet rays of 365 nm, and a yellow optical fixing device 15 for optically fixing the yellow thermosensitive coloring layer.
A magenta optical fixing device 16 for optically fixing the magenta thermosensitive coloring layer. The optical fixing by the optical fixing devices 15 and 16 is performed after the recording of the yellow and magenta thermosensitive coloring layers. The cyan thermosensitive coloring layer is located at the lowermost layer of the thermosensitive layer, and since color mixing does not occur during recording, optical fixing is not performed. Of course, the cyan thermosensitive coloring layer may be optically fixed.

Each of the optical fixing devices 15 and 16 includes an ultraviolet lamp 2
3, 24 and reflectors 26, 27. The reflectors 26 and 27 are used for the ultraviolet lamps 23 and 2 respectively.
The light emitted from 4 is reflected toward the recording paper 3.

2 and 3 show an ultraviolet lamp 23 for yellow. The ultraviolet lamp 23 includes a glass tube 31 and
This is a fluorescent lamp including a pair of bases 32 provided at both ends of the glass tube 31. The base 32 is provided with an electrode for supplying power.

The glass tube 31 is formed by bending a rod-shaped straight tube having a circular cross section a plurality of times. By doing so, the area (effective light emitting area) A1 where the light emitting surface of the ultraviolet lamp 23 and the recording surface of the recording paper 3 face each other is widened. In this example, the number of bends is set to 9, but of course it may be more or less than this. The number of bends is preferably 2 or more, more preferably 3 or more.

Further, when the number of times of bending is set to an odd number, the respective bases 32 of the ultraviolet lamp 23 are arranged on the same side, which facilitates downsizing of the printer. For this reason, it is preferable that the number of bends is an odd number.

The bending angle of each bent portion 31b is about 180 degrees, and the linear portions 31a between the bent portions 31b are formed so as to be parallel to each other. Then, the ultraviolet lamp 23 is arranged such that these linear portions 31a are along the main scanning direction (width direction). The width L1 between the vertices of each bent portion 31b is
The width W of the recording paper 3 is longer than the width W so that the entire surface of the recording paper 3 can be fixed.

Further, in this example, in order to prevent fixing unevenness in the width direction of the recording paper 3, the length L2 of the linear portion 31a is set to the width W.
It is about the same length as. Further, for the same reason, the vicinity of the base 32 of the glass tube 31 having a low emission intensity of ultraviolet rays protrudes from the edge of the recording paper 3.

As described above, the glass tube 31 is formed by bending a rod-shaped straight tube a plurality of times, and such a molding technique is frequently used in the manufacture of chemical experimental instruments, neon lamps, and the like. This is a more general technique as compared with the technique of forming glass into a flat shape described in the conventional example.
Therefore, the manufacturing cost can be suppressed. Further, since the glass tube 31 has a circular cross-sectional shape, it has higher structural strength than a flat lamp. Further, since the structure is simpler than that of the plasma display, the manufacturing cost is low.

The operation of the above apparatus will be described below. When the print instruction is given, the recording paper 3 is fed,
It is transported by the transport roller pair 12. During the first transport in the forward direction, thermal recording of a yellow image by the thermal head 6 and optical fixing by the yellow optical fixing device 15 are performed on the yellow thermosensitive coloring layer. A yellow image is recorded by the thermal head 6, and the recorded portion of the recording paper 3 is sequentially sent to the yellow optical fixing device 15. During this recording, the ultraviolet lamp 23 is turned on to perform optical fixing on the recorded thermosensitive coloring layer for yellow.

Since the effective light emitting area A1 of the ultraviolet lamp 23 is large, it is possible to irradiate the recording paper 3 with a large amount of ultraviolet light having a high luminous intensity. Therefore, a sufficient amount of light for optical fixing can be obtained even if the conveying speed is increased, so that the fixing time can be shortened.

When the thermal recording and the optical fixing of the yellow thermosensitive coloring layer are completed, the conveying roller pair 12 rotates in the reverse direction and the recording paper 3 is conveyed in the reverse direction. When the recording paper 3 returns to the position of the thermal head 6, the second transport in the forward direction is started. During this conveyance, thermal recording and optical fixing of a magenta image are performed on the magenta thermosensitive coloring layer. UV lamp 24
Like the ultraviolet lamp 23, however, since the effective light emitting area A1 is large, the fixing time of the magenta thermosensitive coloring layer is short.

Upon completion of thermal recording and optical fixing of the magenta image, the recording paper 3 is returned to the position of the thermal head 6,
A cyan image is recorded during the third conveyance. When the recording of the cyan image is completed, the recording paper 3 is cut by a cutter (not shown) and discharged.

In addition to the above example, the shape of the ultraviolet lamp may be bent so that the glass tube has a spiral shape. Further, also in this case, the effective light emitting area can be increased. In the above example, one ultraviolet lamp is provided for each optical fixing device, but a plurality of ultraviolet lamps may be provided if necessary.

Further, in the above embodiment, the so-called one-head three-pass type printer for recording an image of three colors with one thermal head has been described, but the present invention includes one thermal head for each color, A three-head, one-pass printer that records three-color images while the recording paper is conveyed in one direction may be used.

[0029]

As described in detail above, the optical fixing device of the thermal printer according to the present invention includes, as a light source for emitting the ultraviolet rays, an ultraviolet lamp including a pair of bases for supplying power and a glass tube. Since this glass tube was bent multiple times to widen the area where the glass tube and the heat-sensitive recording material face each other, it is possible to irradiate a large amount of ultraviolet rays having high emission intensity, so that optical fixing should be performed in a short time. You can Therefore, the printing time can be shortened.

Further, since the area is expanded by bending the ultraviolet lamp, the manufacturing cost is low. Also,
Since it uses a rod-shaped glass tube with a circular cross section, it has high structural strength.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a thermal printer using an optical fixing device of the present invention.

FIG. 2 is an external perspective view of an ultraviolet lamp.

FIG. 3 is a top view of an ultraviolet lamp.

FIG. 4 is an explanatory view showing a conventional straight tube type lamp.

[Explanation of symbols]

2 thermal printer 3 recording paper 15,16 Optical fixing device 23,24 UV lamp 31 glass tube 32 mouthpiece

Claims (4)

[Claims] 1. An optical fixing device for a thermal printer, which irradiates ultraviolet rays to a heat-sensitive recording material on which heat has been recorded to perform optical fixing, using an ultraviolet lamp comprising a pair of caps for supplying power and a glass tube, An optical fixing device for a thermal printer, characterized in that the glass tube is bent a plurality of times to widen the area where the glass tube and the thermosensitive recording material face each other. 2. The optical fixing device for a thermal printer according to claim 1, wherein the glass tube has a circular cross-sectional shape. 3. The optical fixing device for a thermal printer according to claim 1, wherein a straight line portion between a plurality of bent portions of the glass tube is arranged along a width direction of the heat-sensitive recording material. . 4. The optical fixing device for a thermal printer according to claim 3, wherein the length of the linear portion is substantially the same as the width of the thermal recording material.