JPH08108554A - Color thermal printer - Google Patents

Abstract

PURPOSE: To prevent printing irregularity or misregistration caused by load fluctuations by reducing the friction force of a thermal head to color thermal recording paper. CONSTITUTION: A film 32 is interposed between color thermal recording paper 14 and yellow, magenta and cyan thermal heads 26, 27, 28. The film 32 has heat resistance generating no deformation by the heat energy of the respective thermal heads 26-28 and ultraviolet permeability and also has a property at least low in the coefficient of friction as compared with the color thermal recording paper 14. At the time of printing, thermal recording is applied to the color thermal recording paper 14 by the thermal heads 26-28 through the film 32 while the film 32 is fed along with the color thermal recording paper 14. Therefore, the load fluctuations to the feed of the color thermal recording paper due to the thermal heads become slight and no printing irregularity or misregistration is generated.

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 specifically, it uses a plurality of thermal heads,
The present invention relates to a color thermal printer that thermally records a full-color image while conveying a color thermal recording paper in one direction.

[0002]

2. Description of the Related Art A color thermal printer is known in which a full color image is directly heat-recorded on a color heat-sensitive recording paper. This color thermosensitive recording paper has a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer, a yellow thermosensitive coloring layer, and a protective layer, which are layered in this order. When printing, the thermal head is moved relative to the color thermosensitive recording paper in pressure contact. Then, a yellow image is thermally recorded line by line on the yellow thermosensitive coloring layer having the lowest coloring heat energy, and then the yellow thermosensitive coloring layer is optically fixed. Then, a magenta image is thermally recorded on the magenta thermosensitive coloring layer having a medium coloring heat energy, and then the magenta thermosensitive coloring layer is optically fixed. Finally, a cyan image is thermally recorded on the cyan thermosensitive coloring layer having the highest coloring heat energy.

This color thermal recording paper has the property that the frictional resistance to the thermal head decreases as the applied thermal energy increases, as indicated by reference numeral 2 in FIG. Therefore, the yellow thermosensitive coloring layer (Y)
The thermal recording on the magenta thermosensitive coloring layer (M) has a smaller frictional resistance with the thermal head, and the thermal recording on the cyan thermosensitive coloring layer (C) has a smaller frictional resistance than the thermal recording on the cyan recording layer.

Further, in a color thermal printer, a three-pass one-head system in which one thermal head passes through the recording paper three times to perform thermal recording, or one thermal head passes through the recording paper once is used. There is a pass 3 head system. The 1-pass 3-head color thermal printer is equipped with yellow, magenta, and cyan thermal heads corresponding to the yellow, magenta, and cyan thermosensitive coloring layers of the color thermal recording paper. While the head is performing thermal recording on the yellow thermosensitive coloring layer, the thermal head for magenta also press-contacts the color thermosensitive recording paper to perform thermal recording on the magenta thermosensitive coloring layer. Similarly, the thermal head for cyan is also color thermosensitive recording paper. Then, the cyan thermosensitive color developing layer is subjected to thermal recording by pressing.

Then, when the thermal head for yellow which has finished thermal recording first retracts from the color thermal recording paper, the thermal head for magenta retracts next, and the thermal head for cyan finally retracts, color thermal recording A full-color image is heat-recorded on the paper. As described above, the 1-pass 3-head method increases the number of parts by using three thermal heads as compared with the 3-pass 1-head method.
There is an advantage that the printing time can be shortened since it is sufficient to pass the color thermosensitive recording paper once.

[0006]

Since the coefficient of friction of the surface of the color thermosensitive recording paper varies depending on the temperature, the coefficient of friction of the yellow thermal head is the largest and the coefficient of friction of the cyan thermal head is the smallest. In addition, since the frictional force due to each thermal head is different, in the one-pass three-head system, the thermal head different from the thermal head during thermal recording is pressed against the color thermal recording paper and retracted to convey the color thermal recording paper. It gives a large load fluctuation. When the transport load changes, distortion of the platen roller, twist of the rotating shaft, or the like increases or decreases according to the change. If a pulse motor is used as the power source for the transport of color thermosensitive recording paper, the rotor will not reach the step out, but after step feed, it will be slightly displaced from the normal position and the magnetic force Stop at a position that balances the load. Since the transport speed of the recording paper temporarily changes according to the amount of change in the distortion of the transport system, streak-shaped density unevenness and misregistration occur.

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 in which the occurrence of density unevenness and misregistration due to a change in frictional resistance between a thermal head and the surface of a color thermal recording paper is prevented. It is what

[0008]

In order to solve the above problems, the color thermal printer according to claim 1 is a heat-resistant type which is not deformed by the thermal energy of the thermal head between each thermal head and the color thermal recording paper. And a UV transmissive property, and at least a film having a lower surface friction coefficient than the surface of the color thermosensitive recording paper is interposed, the film is conveyed integrally with the color thermosensitive recording paper, and each film is conveyed through the film. A thermal head is used for thermal recording on color thermal recording paper.

In the color thermal printer according to the second aspect of the present invention, an endless film is used, and the thermal head and the color thermal recording paper are repeatedly interposed.

Further, in the color thermal printer according to the third aspect, the film is used in the color thermal printer of the type in which the color thermal recording paper is moved in one direction along a linear conveying path. The color thermal printer described is
The film is used for a color thermal printer of a type in which a color thermal recording paper is moved in one direction along a curved conveyance path. As described above, it is possible to prevent unevenness in density and misregistration by using the film for color thermal printers of various recording paper conveyance forms.

According to a fifth aspect of the present invention, there is provided a color thermal printer in which a plurality of thermal heads are pressed against a color thermal recording paper wound around a platen drum to perform thermal recording. A heat-resistant film that does not deform due to the thermal energy of the thermal head and ultraviolet ray transparency, and has at least a surface friction coefficient lower than that of the surface of the color thermosensitive recording paper. The recording medium is conveyed integrally with the paper, and thermal recording is performed on the color thermosensitive recording paper by each thermal head through this film.

[0012]

When the printing is started, the color thermosensitive recording paper is superposed on the film and conveyed together. When the leading edge of the recording area of the color thermal recording paper reaches the first thermal head, the first thermal head presses the color thermal recording paper through the film to perform thermal recording. This film is
Since the friction coefficient for the thermal head is quite small,
The load is much smaller than when the thermal head is pressed directly onto the color thermal recording paper. Further, since the film transmits ultraviolet rays, the ultraviolet rays of the optical fixing device are applied to the color thermosensitive recording paper to optically fix the thermosensitive coloring layer which is first thermally recorded. When the leading edge of the recording area of the color thermosensitive recording paper reaches the next thermal head, the next thermal head presses the color thermosensitive recording paper through the film similarly to the first thermal head. Also in this case, since the coefficient of friction of the film is considerably small, the load variation of the transport of the color thermosensitive recording paper is small. Further, the frictional resistance at each thermal head portion is also the same. This reduces the occurrence of density unevenness and misregistration. Further, when a loop-shaped film is used, the film is repeatedly interposed between the thermal head and the color thermosensitive recording paper, so that the film need not be replaced.

[0013]

EXAMPLE FIG. 2 showing an example of the layer structure of color thermosensitive recording paper.
In the color thermosensitive recording paper 14, the cyan thermosensitive coloring layer 17, the magenta thermosensitive coloring layer 18, the yellow thermosensitive coloring layer 1
9 and the protective layer 20 are sequentially layered on the support 16.
These thermosensitive coloring layers 17 to 19 are layered 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 1 is used.
9 and the magenta thermosensitive coloring layer 18 are replaced. An intermediate layer for adjusting the thermal sensitivity of the thermosensitive coloring layer is formed between the thermosensitive coloring layers, but it is omitted in the drawing.

Further, in FIG. 3 showing the color forming characteristics of the thermosensitive coloring layers 17 to 19, the coloring thermogenic energy is lowest in the yellow thermosensitive coloring layer Y and highest in the cyan thermosensitive coloring layer C.
As a result, by changing the heat energy applied by the thermal head, the thermosensitive coloring layers of three colors can be selectively colored.

In FIG. 1 showing the outline of a color thermal printer, a pair of conveying rollers 10, 11, 12, 13 are arranged at a substantially constant interval so as to form a linear conveying path. By these conveying roller pairs 10 to 13,
The color thermosensitive recording paper 14 is conveyed to the right at a constant speed.
Three platen rollers 22, 23, 24 made of hard rubber are rotatably arranged between the conveying roller pairs 10 to 13. These platen rollers 22 to 24 are rotated at a constant speed by a pulse motor connected to the platen shafts 22a, 23a and 24a. The color thermosensitive recording paper 14 is conveyed on the platen rollers 22 to 24 by the conveying roller pairs 10 to 13.

Further, these platen rollers 22 to 24
A thermal head 26 for yellow, a thermal head 27 for magenta, and a thermal head 28 for cyan are provided in this order from above on the upstream side in the transport direction of the color thermosensitive recording paper 14, and these are arranged vertically. . At the lower end of each of the thermal heads 26 to 28, there are heating element arrays 26a, 27a, 28 in which a plurality of heating elements are arranged in a line.
a is provided. These heating element arrays 26a-2
8a is formed long in the direction perpendicular to the direction in which the color thermosensitive recording paper 14 is conveyed. In addition, each thermal head 26
Denoted at 28 are thermal recording positions where the color thermal recording paper 14 is pressed against the color thermal recording paper 14 by means of solenoids, cams, etc.
It is movable between the retracted position and the retracted position.

A yellow layer optical fixing device 36 is provided between the yellow thermal head 26 and the magenta thermal head 27, and a magenta layer light is provided between the magenta thermal head 27 and the cyan thermal head 28. Fixer 3
7 are provided. The yellow-layer optical fixing device 36 is a rod-shaped ultraviolet lamp 3 having an emission peak of about 420 nm.
6a and a lamp house 36b. The magenta layer optical fixing device 37 is composed of an ultraviolet lamp 37a having an emission peak of about 365 nm and a lamp house 37b.

A pair of conveying rollers 10 to 13 and an auxiliary roller 3 arranged above the conveying path of the color thermosensitive recording paper 14.
A loop-shaped film 32 is hung over 0 and 31, and is conveyed in the arrow direction at the same speed as the color thermosensitive recording paper 14. The film 32 is formed by molding polyfluorinated ethylene (Teflon), polyimide or the like to a thickness of about 1 to 10 μm, and has a width wider than the width of the recording area of the color thermosensitive recording paper 14.

Further, the film 32 has heat resistance so that it is not thermally deformed even when heat energy higher than that applied to the cyan thermosensitive coloring layer shown in FIG. 3 is applied. As a result, the thermal heads 26 to 2 are passed through the film 32.
Even when heat recording is performed on the color thermosensitive recording paper 14 in 8, the film 32 does not deform, and since the film 32 has a loop shape, it can be repeatedly used, and it is necessary to perform troublesome work such as replacement. There is no. Further, since the film 32 transmits ultraviolet rays, the yellow-layer optical fixing device 3
It is possible to directly irradiate the color thermosensitive recording paper 14 with the ultraviolet light emitted from the image fixing device 6 and the magenta layer optical fixing device 37.

Further, as indicated by reference numeral 34 in FIG. 4, the coefficient of friction on the surface of the film 32 is obtained from the coefficient of friction on the surface of the color thermosensitive recording paper 14 at the time of thermal recording on the cyan thermosensitive coloring layer 17 indicated by reference numeral 2. Is also low. As a result, when the thermal heads 26 to 28 are pressed against the color thermosensitive recording paper 14, the load variation on the conveyance of the color thermosensitive recording paper 14 due to frictional resistance is reduced. Furthermore, each thermal head 2
The frictional resistances in the portions 6 to 28 are the same as the frictional resistance with the film 32, and are equal to each other.
The unevenness in the conveyance speed of the color thermosensitive recording paper 14 and the like does not occur in the parts 28 to 28. In addition, each thermal head 26-28
The thermal energy of the thermal heads 26 to 28 is applied to the color thermosensitive coloring layer 14 via the film 32.
Is determined in consideration of the heat transfer characteristics of the film 32.

Next, the operation of the above embodiment will be described. As shown in FIG. 1, when the leading end of the recording area of the color thermosensitive recording paper 14 reaches the yellow thermal head 26 by the conveyance of the conveying roller pair 10, the yellow thermal head 26 is moved to the thermal recording position by a cam or solenoid. The heating element array 26a is lowered toward the color thermosensitive recording paper 14 through the film 32 which is conveyed at the same speed as the color thermosensitive recording paper 14.

The heating element array 26a of the yellow thermal head 26 generates a slightly larger heat energy in accordance with the coloring characteristics of the yellow thermosensitive coloring layer 19 shown in FIG. 3 to heat the yellow image line by line. Record. When the thermally recorded yellow thermosensitive coloring layer 19 reaches the yellow layer photofixing device 36, near-ultraviolet rays of about 420 nm are irradiated from the ultraviolet lamp 36a onto the color thermosensitive recording paper 14, and the next magenta thermosensitive coloring layer 18 is formed. It is fixed to the extent that the yellow thermosensitive coloring layer 19 does not develop color during thermal recording.

When the leading end of the recording area of the color thermosensitive recording paper 14 reaches the magenta thermal head 27, the magenta thermal head 27 is replaced by the yellow thermal head 2.
Similar to 6, the cam is moved to a thermal recording position by a solenoid or the like, and the color thermal recording paper 14 is pressed against the color thermal recording paper 14 via the film 32 conveyed at the same speed as the color thermal recording paper 14. The coefficient of friction of the surface of the film 32 is shown in FIG.
As shown by, it is low, so the magenta thermal head 27
Friction resistance with is small. Therefore, color thermal recording paper 1
The load fluctuation of the conveyance of 4 becomes small, and the color thermal recording paper 1
Since the conveyance speed of No. 4 does not change significantly, density unevenness and misregistration due to the yellow thermal head 26 do not occur.

The heating element array 26a of the magenta thermal head 26 generates heat at a temperature slightly higher than the magenta thermosensitive coloring layer 18 shown in FIG.
Thermal recording of magenta image line by line. This heat-recorded magenta thermosensitive coloring layer 18 is the magenta layer optical fixing device 3.
When it reaches 7, it is almost 365n from the ultraviolet lamp 37a.
The color thermosensitive recording paper 14 is irradiated with ultraviolet rays in the vicinity of m, and is fixed to the extent that the magenta thermosensitive coloring layer 18 does not develop color during the next thermal recording of the cyan thermosensitive coloring layer 17.

When the leading edge of the recording area of the color thermosensitive recording paper 14 reaches the cyan thermal head 28, the cyan thermal head 28 is heated by a cam, a solenoid or the like like the yellow thermal head 26 and the magenta thermal head 27. The color thermosensitive recording paper 14 is pressed through the film 32 which is moved down to the recording position and conveyed at the same speed as the color thermosensitive recording paper 14. Also at this time, film 3
Due to the low coefficient of friction of 2, the transfer of the color thermosensitive recording paper 14 is subject to only a slight change in load, and therefore the transfer speed does not change significantly.
6 and the thermal head 27 for magenta does not cause density unevenness or misregistration.

The heating element array 28a of the cyan thermal head 28 generates slightly larger heat energy in accordance with the color development characteristics of the cyan thermosensitive color development layer 17 shown in FIG. 3 to thermally record a cyan image line by line. To do. The cyan thermosensitive coloring layer 17 has a value such that the coloring heat energy does not develop in a normal storage state, so that the cyan thermosensitive coloring layer 17 is not provided with optical fixing property.

Further, while the magenta thermosensitive coloring layer 18 and the cyan thermosensitive coloring layer 17 are being thermally recorded, the yellow thermosensitive coloring layer 19 has completed the thermal recording of all yellow images,
The yellow thermal head 26 moves to the retracted position. Film 32 and yellow thermal head 2
Since the frictional resistance with respect to No. 6 is small, even if the yellow thermal head 26 moves to the retracted position, a large load fluctuation is not given to the conveyance of the color thermosensitive recording paper 14 and the change in the conveyance speed becomes small, so that the magenta Thermal head 27
Also, density unevenness and misregistration due to the cyan thermal head 28 do not occur. Further, when the yellow thermal head 26 is moved to the retracted position, the yellow layer optical fixing device 36 is turned off.

Next, when the thermal recording on the magenta thermosensitive coloring layer 18 is completed, the magenta thermal head 27 is moved to the retracted position by a cam or a solenoid, like the yellow thermal head 26. Also in this case, the film 3
Since the frictional resistance between No. 2 and the magenta thermal head 27 is small, a large load fluctuation is not applied to the conveyance of the color thermosensitive recording paper 14, and the change in the conveyance speed is small. No unevenness or misregistration occurs. When the magenta thermal head 27 moves to the retracted position, the magenta layer optical fixing device 37 is turned off.

When the thermal recording on the cyan thermosensitive coloring layer 17 is completed, the cyan thermal head 28 is retracted from the film 32, and the color thermosensitive recording paper 14 is ejected to the paper ejection tray or the like by the conveying roller pair 13.

As shown in FIG. 5, the film 32 is used as a support, and a lubricant layer 40 of silicon or the like is formed on the film 32.
By providing, the frictional resistance with the thermal head is further reduced, and it is possible to reduce the load fluctuation on the conveyance of the color thermosensitive recording paper.

Further, as shown in FIG.
5, 46, 47, 48 and each platen roller 49, 5
A color thermal printer in which 0 and 51 are arranged so as to draw a curved line and which conveys the color thermal recording paper 52 in a curved line,
The film 53 can be used, and it is possible to prevent uneven density and misregistration by reducing load fluctuations during pressure contact of the yellow thermal head 54, the magenta thermal head 55, and the cyan thermal head 56. Compared with a color thermal printer having a linear transport path, such a color thermal printer can reduce the size of the color thermal recording paper 52 in the transport direction with almost no change in the size in the height direction. Has an effect on.

Further, as shown in FIG. 7, the color thermosensitive recording paper 60 is wound around a large-diameter platen drum 61, and is arranged on the outer periphery of the platen drum 61 while rotating the platen drum 61 counterclockwise in the figure. The color thermal printer for sequentially recording the full-color image by pressing the yellow thermal head 62, the magenta thermal head 63, and the cyan thermal head 64 onto the color thermal recording paper 60 in order to prevent uneven density and misregistration by using the film 65. Can be prevented. In such a color thermal printer, since it is difficult to use the film 65 in a loop shape, the film 6 is provided near the platen drum 61.
A supply roll 66 in which 5 is wound in a roll shape and a recovery roll 67 which is wound after being conveyed together with the color thermosensitive recording paper 60 are arranged. However, since the film 65 can be used repeatedly, after all the films 65 are wound around the recovery roll 67, the recovery roll 67 can be set and reused as a supply roll. As a result, the cost of the film can be minimized.

In the above embodiment, the thermal recording type color thermal line printer has been described. However, the present invention can be applied to a serial printer using color thermal recording paper.

[0034]

As described above, in the color thermal printer of the present invention, a film having a small coefficient of friction with respect to the thermal head is interposed between each thermal head and the color thermal recording paper. By using a material having heat resistance that does not deform due to the thermal energy of the head and ultraviolet transparency, the load on the conveyance of the color thermosensitive recording paper by the thermal head changes little, and printing unevenness and misregistration do not occur. Further, since the frictional resistances in all the thermal head portions are equal, unevenness in the conveyance speed of the color thermosensitive recording paper in each thermal head portion does not occur, and density unevenness and misregistration do not occur. Further, when the film is looped, it can be repeatedly interposed between the thermal head and the thermal recording paper, and troublesome work such as film replacement can be eliminated.

[Brief description of drawings]

FIG. 1 is a schematic view of a 1-pass 3-head type color thermal printer embodying the present invention.

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

FIG. 3 is a graph showing color forming characteristics of each thermosensitive color developing layer.

FIG. 4 is a graph showing the coefficient of friction of color thermosensitive recording paper and film.

FIG. 5 is an explanatory view showing another embodiment of the film.

FIG. 6 is a schematic view of a 1-pass 3-head type color thermal printer having a curved conveyance path.

FIG. 7 is a schematic view of a platen drum type one-pass three-head color thermal printer.

[Explanation of symbols]

 14 Color Thermal Recording Paper 26 Thermal Head for Yellow 27 Thermal Head for Magenta 28 Thermal Head for Cyan 32 Film 40 Lubricant Layer

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location 7416-2H B41M 5/26 Z

Claims (5)

[Claims] 1. A color thermosensitive recording paper in which a plurality of thermosensitive coloring layers are layered on a support is used, and a plurality of thermal heads and ultraviolet rays for optical fixing are irradiated along the conveying direction of the color thermosensitive recording paper. In the color thermal printer, a thermal fixing device is disposed, and each thermal head is brought into pressure contact with the color thermal recording paper while the color thermal recording paper moves to thermally record a full-color image on the color thermal recording paper. Between the thermal head and the color thermal recording paper, a film having heat resistance that does not deform due to the thermal energy of the thermal head and ultraviolet transparency and at least a surface friction coefficient lower than that of the surface of the color thermal recording paper is interposed. , A color characterized in that the thermal recording is performed on the color thermosensitive recording paper by each thermal head while conveying the film integrally with the color thermosensitive recording paper. Thermal printer. 2. The color thermal printer according to claim 1, wherein the film has a loop shape, and is repeatedly interposed between the thermal head and the color thermal recording paper. 3. The color thermosensitive recording paper is moved in one direction by a plurality of conveying roller pairs arranged along a linear conveying path, and each thermal head is appropriately arranged between the plurality of conveying roller pairs. The color thermal printer according to claim 1, wherein the color thermal printer is arranged so as to face a plurality of platen rollers arranged at various intervals. 4. The color thermosensitive recording paper is moved in one direction by a plurality of conveying roller pairs arranged along a curved conveying path, and each thermal head is appropriately arranged between the plurality of conveying roller pairs. The color thermal printer according to claim 1, wherein the color thermal printer is arranged so as to face a plurality of platen rollers arranged at various intervals. 5. A color thermosensitive recording paper in which a plurality of thermosensitive coloring layers are layered on a support is used, and a plurality of thermal heads and optical fixing are provided on the outer periphery of a large diameter platen drum around which the color thermosensitive recording paper is wound. A thermal printer for irradiating ultraviolet rays for use in the application, and each thermal head is pressed against the color thermal recording paper while the platen drum makes one revolution to thermally record a full-color image on the color thermal recording paper. In each of the above-mentioned thermal heads and the color thermal recording paper, there is heat resistance that does not deform due to the thermal energy of the thermal head and UV transparency, and at least the surface friction coefficient is lower than the surface of the color thermal recording paper. Thermal recording is performed on the color thermosensitive recording paper with each thermal head while the film is being carried and the film is conveyed integrally with the color thermosensitive recording paper. Color thermal printer according to claim Rukoto.