JPH08118689A - Color thermal printer - Google Patents

Abstract

PURPOSE: To provide a color thermal printer in which uniform photofixing can be executed in the lateral direction of a color thermal recording sheet. CONSTITUTION: Ultraviolet lamps 7, 8 are slightly longer than the lateral length of a color thermal record sheet 4. An opening 11 for releasing the ultraviolet rays radiated from the centers of the lamps 7, 8 and a reflecting surface for reflecting it toward both the ends of the sheet 4 are formed at a reflecting plate 9. Since the lamps 7, 8 reflects only at the ends by the plate 9, the rays emitted to the sheet 4 is substantially uniform on the entire area, thereby uniformly fixing it.

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 capable of performing uniform light fixing.

[0002]

2. Description of the Related Art Thermal printers include thermal printers and thermal transfer printers. Among them, thermal printers are widely used because they can directly record an image directly on thermal recording paper. In addition, recently, a color thermal printer using color thermal recording paper has been sold by the applicant. This color thermosensitive recording paper is one in which a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer and a yellow thermosensitive coloring layer are sequentially laminated on a support, and thermal recording is performed in order from the thermosensitive coloring layer on the surface. Then, when heat recording is performed on the next thermosensitive coloring layer, in order to prevent the upper thermorecording thermosensitive coloring layer from developing color again, the color-developing ability of the heat-recorded thermosensitive coloring layer is lost by optical fixing. ing.

[0003]

A rod-shaped ultraviolet lamp is used for the optical fixing, and the ultraviolet lamp emits ultraviolet rays in a wavelength range peculiar to each thermosensitive coloring layer. Further, the ultraviolet lamp has a different amount of light emission depending on its part. As shown in FIG. 6, the ultraviolet lamp has the largest amount of light emission in the central portion, and the amount of light emission decreases as it approaches both ends. As a result, as indicated by a broken line 35 in FIG. 7, the irradiation amount near both ends of the color thermosensitive recording paper is smaller than that at the central part, and there is a problem that uneven fixing occurs.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a color thermal printer capable of performing uniform optical fixing.

[0005]

In order to solve the above-mentioned problems, a color thermal printer according to claim 1 is provided with a reflecting plate behind both ends of an ultraviolet lamp for reflecting ultraviolet rays toward color thermal recording paper. Are provided respectively. According to this, the ultraviolet rays irradiated to both ends of the color thermosensitive recording paper are increased, and the ultraviolet illuminance at both ends of the color thermosensitive recording paper is
It becomes almost equal to the center of the color thermosensitive recording paper, and uniform optical fixing is performed.

Further, in the color thermal printer according to the second aspect of the invention, the two reflecting plates provided behind the ultraviolet lamp are integrated, and the opening is formed in the portion facing the central portion of the ultraviolet lamp. Is. According to this, claim 1
The effect is the same as that described, and the cost can be reduced and the manufacturing efficiency can be improved by reducing the number of parts.

Further, in the color thermal printer according to the third aspect of the present invention, a reflecting plate for reflecting ultraviolet rays to both ends of the color thermal recording paper is provided behind the ultraviolet lamp. According to this, the ultraviolet rays radiated to both ends of the color thermosensitive recording paper increase, the ultraviolet illuminance at both ends of the color thermosensitive recording paper becomes almost equal to the central part of the color thermosensitive recording paper, and uniform light fixing is performed. Be seen.

Further, in the color thermal printer according to the fourth aspect, a rough surface having a small reflectance is formed behind the ultraviolet lamp in a portion facing the central portion of the ultraviolet lamp, and a portion facing both ends of the ultraviolet lamp. Is a reflective plate having a reflective surface with a high reflectance formed therein. According to this, the ultraviolet rays radiated to both ends of the color thermosensitive recording paper increase, the ultraviolet illuminance at both ends of the color thermosensitive recording paper becomes almost equal to the central part of the color thermosensitive recording paper, and uniform light fixing is performed. Be seen.

[0009]

1, a platen drum 2 is intermittently rotated in a direction of an arrow about a rotary shaft 3 by a pulse motor (not shown) in FIG. A color thermosensitive recording paper 4 is wound around the outer periphery of the platen drum 2, and the tip of the color thermosensitive recording paper 4 is fixed by a clamper 5. Further, on the outer periphery of the platen drum 2, a thermal head 6, a magenta fixing ultraviolet lamp 7, a yellow fixing ultraviolet lamp 8 and a reflecting plate 9 covering the upper sides of these ultraviolet lamps 7 and 8 are arranged.

Although not shown, the thermal head 6 is provided with a heating element array. In this heating element array, a large number of heating elements are formed in a line in the axial direction of the platen drum 2. Each heating element presses and heats the color thermosensitive recording paper 4 so that dots are colored in the pixels having a square shape.

The magenta fixing ultraviolet lamp 7 and the yellow fixing ultraviolet lamp 8 are rod-shaped. The magenta fixing ultraviolet lamp 7 emits ultraviolet rays having an emission peak near 365 nm, and the yellow fixing ultraviolet lamp 8 is It emits ultraviolet light having an emission peak near 425 nm. Also,
As shown in FIG. 2, the length of the yellow fixing ultraviolet lamp 8 is slightly longer than the length of the color thermosensitive recording paper 4 in the width direction. It should be noted that it is conceivable that the length of the yellow fixing ultraviolet lamp 8 is increased and only the central portion of the yellow fixing ultraviolet lamp 8 is used for optical fixing. However, in this case, a long ultraviolet lamp is required,
The cost increases and the size of the device increases.

The reflector 9 is made of a material having a high heat dissipation effect such as aluminum, and is designed so that fluctuations in the amount of light emitted from the ultraviolet lamp due to heat accumulation are small. An opening 11 is provided at a portion of the reflector 9 facing the center of each ultraviolet lamp 7, 8.
The ultraviolet rays emitted from the ultraviolet lamps 7 and 8 to the rear side escape to the outside of the reflection plate 9 through the opening 11. As a result, the illuminance of the ultraviolet rays with which the central portion of the color thermosensitive recording paper 4 is irradiated is slightly weakened. Further, the reflection plate 9 has a high reflectance in a portion facing both ends of each of the ultraviolet lamps 7 and 8.
2 and 13 are formed. These reflecting surfaces 12 and 13 are
It is formed by mirror-finishing the surface of the reflector 9 or by vapor-depositing aluminum. The ultraviolet rays emitted from the opposite ends of the ultraviolet lamps 7 and 8 to the back side are reflected by the reflecting surfaces 12 and 13 and are applied to the edges of the color thermosensitive recording paper 4. As a result, the illuminance of ultraviolet rays applied to both ends of the color thermosensitive recording paper 4 becomes slightly stronger, and
As indicated by reference numeral 36, the illuminance is substantially equal to the illuminance in the central portion where the illuminance is weakened by the opening 11, and the color thermosensitive recording paper 4
Can be fixed uniformly.

As shown in FIG. 3, the color thermosensitive recording paper 4 is used.
Is a cyan thermosensitive coloring layer 16, a magenta thermosensitive coloring layer 17, a yellow thermosensitive coloring layer 18, a protective layer 19 on the support 15.
Are sequentially layered. The cyan thermosensitive coloring layer 16 has the lowest thermal sensitivity, and develops cyan when a large amount of heat energy is applied. The magenta thermosensitive coloring layer 17 has a medium thermal sensitivity and develops magenta when heated. In addition, the magenta thermosensitive coloring layer 17 has almost 365
It has a light fixing property by ultraviolet rays of nm. The yellow thermosensitive coloring layer 18 has the highest thermal sensitivity, and develops yellow when a relatively small amount of heat energy is applied. The yellow thermosensitive coloring layer 18 has a light fixing property by an ultraviolet ray having a wavelength of about 425 nm. The heat sensitivity of the cyan thermosensitive coloring layer 16 is such that no color is developed in a normal storage state, so that the photofixability is not provided. These thermosensitive coloring layers 16
Nos. 18 to 18 are arranged in the order of thermal recording. In addition,
Although not shown in the drawing, an intermediate layer for adjusting thermal sensitivity is formed between the thermosensitive color developing layers.

Next, the operation of the above embodiment will be described. As shown in FIG. 1, when a print start switch (not shown) is operated, the color thermosensitive recording paper 4 is fed,
The tip is clamped by the clamper 5. The platen drum 2 is intermittently rotated in the arrow direction by a pulse motor, and when the leading end of the recording area of the color thermosensitive recording paper 4 reaches the thermal head 6, the heating element array of the thermal head 6 is pressed against the color thermosensitive recording paper 4. It The heating element array is heated to a temperature that matches the color-developing characteristics of the yellow thermosensitive coloring layer 15, and a yellow image is thermally recorded line by line.

When the portion of the color thermosensitive recording paper 4 on which the yellow image is thermally recorded reaches the yellow fixing ultraviolet lamp 8, the yellow fixing ultraviolet lamp 8 is turned on and the emission peak is 425 nm. It emits ultraviolet rays in the vicinity. UV lamp for yellow fixing 8
The ultraviolet rays emitted from the color thermosensitive recording paper 4 to the color thermosensitive recording paper 4 are emitted from the back side of the color thermosensitive recording paper 4 through the opening 11 and the ultraviolet rays at the central portions escape, and the ultraviolet rays at both ends are reflected by the reflecting surfaces 12 and 13. Is irradiated to the edge of the. As a result, the illuminance is substantially equal over the entire width of the color thermosensitive recording paper 4, and the yellow thermosensitive coloring layer 18 is uniformly fixed.

The color thermosensitive recording paper 4 on which the thermal recording and fixing on the yellow thermosensitive coloring layer 18 is completed is the platen drum 2
The tip reaches the thermal head 6 again by the rotation of.
The thermal head 6 is temporarily retracted when passing through the clamper 5, and again contacts the color thermosensitive recording paper 4 after passing through the clamper 5. The heating element array is heated to a temperature according to the color development characteristics of the magenta thermosensitive coloring layer 17, and a magenta image is thermally recorded line by line.

When the portion of the color thermosensitive recording paper 4 on which the magenta image is thermally recorded reaches the magenta fixing ultraviolet lamp 7, ultraviolet rays having an emission peak near 365 nm are emitted. The ultraviolet rays emitted from the magenta fixing ultraviolet lamp 7 are similar to those of the yellow fixing ultraviolet lamp 8 in the opening 1
Due to the effect of 1 and the reflecting surfaces 12 and 13, the entire area of the color thermosensitive recording paper 4 in the width direction is irradiated with substantially equal illuminance. As a result, the magenta thermosensitive coloring layer 17 is uniformly fixed.

The color thermosensitive recording paper 4 on which the thermal recording and fixing on the magenta thermosensitive coloring layer 17 is completed is the platen drum 2
The tip of the recording area is again moved to the thermal head 6 by the rotation of
To reach. The heating element array of the thermal head 6 is heated to a temperature according to the color developing characteristics of the cyan thermosensitive coloring layer 16, and thermally records a cyan image line by line. During the thermal recording of the cyan image, the ultraviolet lamp is not turned on, and the thermally recorded color thermosensitive recording paper 4 is discharged to the paper discharge tray or the like through the discharge passage.

Further, in order to uniformly irradiate the color thermosensitive recording paper 4 with ultraviolet rays, a reflecting plate 21 as shown in FIG. 4 may be used. A rough surface 22 having a low ultraviolet reflectance is formed in the central portion of the reflecting plate 21, and the ultraviolet rays emitted from the ultraviolet lamps 7 and 8 are diffusely reflected by the rough surface 22, so that the color thermosensitive recording is performed. The central portion of the paper 4 is not irradiated, and the illuminance is slightly weakened. Also the reflector 2
1 is provided with the reflecting surfaces 23 and 24 as in the above-described embodiment, and the illuminance at the end of the color thermosensitive recording paper 4 can be increased. As a result, as indicated by reference numeral 36 in FIG. 7, the illuminance of ultraviolet rays becomes substantially the same in the entire widthwise direction of the color thermosensitive recording paper 4, and uniform fixing can be performed.

Further, using a reflector as shown in FIG. 5,
The ultraviolet rays applied to the color thermosensitive recording paper 4 can be made uniform. The reflecting plate 26 has reflecting surfaces 27, 28,
29 and 30 are formed, and the ultraviolet rays emitted from the ultraviolet lamps 7 and 8 to the rear side are condensed by the reflecting surfaces 27 to 30 on both ends of the color thermosensitive recording paper 4. As a result, the illuminance of ultraviolet rays radiated to the central portion of the color thermosensitive recording paper 4 becomes weak and the ultraviolet rays radiated to both end portions become strong, so that the illuminance of ultraviolet rays becomes substantially equal.

Although the platen drum type color thermal printer has been described in the above embodiment, the conveying roller pair is arranged in a linear path, and the color thermal recording paper is nipped to linearly reciprocate with respect to the thermal head. It can also be used in a reciprocating color thermal printer.
Further, the present invention can be applied to a three-head, one-pass type color thermal printer which uses three thermal heads and thermally records an image of three colors by one rotation or linear conveyance.

[0022]

As described above, in the color thermal printer of the present invention, by providing an opening or a rough surface in the central portion of the reflection plate, the illuminance of ultraviolet rays radiated to the central portion of the color thermal recording paper is weakened, By providing reflective surfaces on both ends of the reflector, the illuminance of ultraviolet rays radiated to both ends of the color thermosensitive recording paper is strengthened, so that the illuminance of ultraviolet rays radiated to the entire area of the color thermosensitive recording paper becomes almost equal and uniform. Light fixation can be performed. Further, since the reflecting plates that reflect light are collected on both ends of the color thermosensitive recording paper, uniform optical fixing can be performed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a platen drum type color thermal printer.

FIG. 2 is a sectional view of an essential part of a reflector.

FIG. 3 is an explanatory diagram showing a layer structure of color thermosensitive recording paper.

FIG. 4 is a cross-sectional view of a main part of a reflection plate of another embodiment.

FIG. 5 is a cross-sectional view of a main part of a reflection plate of still another embodiment.

FIG. 6 is a graph showing the amount of light emitted from an ultraviolet lamp.

FIG. 7 is a graph showing the illuminance of ultraviolet rays applied to a color thermosensitive recording paper.

[Explanation of symbols]

 4 Color thermal recording paper 7 UV lamp for magenta fixing 8 UV lamp for yellow fixing 9, 21, 26 Reflector 11 Opening

Claims (4)

[Claims] 1. At least first to color different colors
A color thermosensitive recording paper on which a third thermosensitive coloring layer is layered is used, and while the color thermosensitive recording paper is moved relative to the thermal head, thermal recording is selectively performed on each thermosensitive coloring layer by the thermal head, A color thermal printer which irradiates ultraviolet rays from a rod-shaped ultraviolet lamp arranged in a direction perpendicular to the moving direction of the color thermal recording paper to the heat-recorded portion to perform optical fixing, wherein both ends of the ultraviolet lamp are A color thermal printer characterized in that a reflector for reflecting ultraviolet rays toward the color thermal recording paper is provided behind each of these. 2. The color thermal printer according to claim 1, wherein the two reflectors are integrally provided, and an opening is formed in a portion facing a central portion of the ultraviolet lamp. . 3. At least first to color different colors
A color thermosensitive recording paper on which a third thermosensitive coloring layer is layered is used, and while the color thermosensitive recording paper is moved relative to the thermal head, thermal recording is selectively performed on each thermosensitive coloring layer by the thermal head, A color thermal printer which irradiates ultraviolet rays from a rod-shaped ultraviolet lamp arranged in a direction perpendicular to the moving direction of the color thermal recording paper to the heat-recorded portion to perform optical fixing, is provided behind the ultraviolet lamp. A color thermal printer, characterized in that it is provided with a reflector for reflecting ultraviolet rays toward both ends of the color thermal recording paper. 4. At least first to color different colors
A color thermosensitive recording paper on which a third thermosensitive coloring layer is layered is used, and while the color thermosensitive recording paper is moved relative to the thermal head, thermal recording is selectively performed on each thermosensitive coloring layer by the thermal head, A color thermal printer which irradiates ultraviolet rays from a rod-shaped ultraviolet lamp arranged in a direction perpendicular to the moving direction of the color thermal recording paper to the heat-recorded portion to perform optical fixing, is provided behind the ultraviolet lamp. A rough plate having a low reflectance is formed in a portion facing the central portion of the ultraviolet lamp, and a reflecting plate having a reflecting surface having a high reflectance is disposed in the portions facing both ends of the ultraviolet lamp. And color thermal printer.