JPH08216464A - Thermal printer - Google Patents

Abstract

PURPOSE: To prevent a heating element array part protruding from both the ends of a thermal recording paper sheet from being damaged due to a contact with a platen. CONSTITUTION: Two protective belts 18, 19 are applied over a platen roller 12, and rollers 25, 26 and rollers 27, 28. The protective belts 18, 19 rotate with the platen roller 12. The protective belts 18, 19 are moved in the axial direction of the platen roller 12 according to the width of paper sheet to form a slightly smaller interval than the width of a color thermal recording paper sheet 10. Both the ends of the color thermal recording paper sheet 10 are placed on the protective belts 18, 19. The part protruding from the color thermal recording paper sheet 10 out of a heating element array 13a is brought into contact with the protective belts 18, 19, thus causing no contact with a platen formed out of hard rubber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer,
More specifically, it relates to a thermal printer in which a heating element array of a thermal head is prevented from being damaged by a platen roller.

[0002]

2. Description of the Related Art In a thermal printer, a thermal head is arranged so as to face a platen roller made of hard rubber. The thermal recording paper is pressed and heated by the heating element array of the thermal head when being conveyed on the platen roller,
The image is recorded in color.

By the way, if the pressing force when the thermal head is pressed against the thermosensitive recording paper is small, the heat transfer coefficient becomes small, so that the coloring density becomes low even if the heating amount of the heating element is the same. Therefore, in order to obtain a sufficient pressing force, the thermal head is strongly pressed against the thermal recording paper so that the thermal recording paper slightly sinks into the surface of the platen.

[0004]

When the heating element array of the thermal head is larger than the width of the thermal recording paper, when the thermal head is pressed against the thermal recording paper, the heating elements at both ends of the heating element array are Since it directly contacts the platen, this part may be damaged.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color thermal printer in which both ends of a heating element array protruding from a thermal recording paper are prevented from being damaged by a platen roller.

[0006]

In order to solve the above-mentioned problems, in the thermal printer according to claim 1, a pair of protective belts are arranged in a state of being partially wound on both sides of the platen roller, and the thermal recording paper Both ends of the heating element array protruding from both sides are supported by a pair of protective belts so that they do not contact the platen roller. Even if the paper width is narrower than the heating element array, both ends of the heating element array are This part is not damaged because it does not directly contact the platen roller.

In the thermal printer according to the second aspect of the invention, each protective belt is hung on two rollers in addition to the platen roller, and the shape viewed from the side forms a triangle. In the thermal printer according to claim 3, the two rollers are flanged rollers which are movable in the axial direction of the platen roller, and the distance between the pair of protective belts can be changed according to the width of the thermal recording paper. It was done.

[0008]

EXAMPLE FIG. 3 showing an example of the layer structure of a color thermosensitive recording paper.
In the color thermosensitive recording paper 10, a protective layer 5, a yellow thermosensitive coloring layer 6, a magenta thermosensitive coloring layer 7, and a cyan thermosensitive coloring layer 8 are sequentially laminated on a support 9. Each of these thermosensitive coloring layers 6 to 8 is 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 6 and the magenta thermosensitive coloring layer. 7 is replaced. Each of these thermosensitive coloring layers 6
Since the deeper layers have higher coloring heat energies 8 to 8, the coloring heat energies applied by the thermal head 13 are changed so that the three color thermosensitive coloring layers can be selectively colored.

As shown in FIG. 1, the color thermosensitive recording paper 10 is nipped by a conveying roller pair 11 and conveyed on a platen roller 12. This transport roller pair 11,
The platen roller 12 is rotated by a pulse motor (not shown). These transport roller pair 11 and platen roller 12
And intermittently or continuously rotating at the same speed in the same direction,
The color thermosensitive recording paper 10 is conveyed.

A vertical thermal head 13 is provided so as to face the platen roller 12. The thermal head 13 is provided with a heating element array 13a in which a large number of heating elements are arranged in a line in the main scanning direction, and each heating element generates heat energy according to the density of a pixel.
The thermal head 13 presses the color thermosensitive recording paper 10 supported on the platen roller 12 while the color thermosensitive recording paper 10 is being conveyed.

In the case of a narrow color thermosensitive recording paper, since the heating element array 13a contacts the platen roller 12, the heating element array 13a is scratched and scratched. Therefore, the protective belt 18 is hung on one side of the platen roller 12 and the rollers 25 and 26 in a triangular shape. Similarly, the protective belt 19 is also hung on the other side of the platen roller 12 and the rollers 27 and 28.

As shown in FIG. 2, the rollers 25 and 26 are attached to the moving base 30. These rollers 2
Roller bodies 25a and 26a and flanges 25b to 26b are formed on the rollers 5 and 26, respectively. Rollers 27, 28
Since the same applies to the above, only the reference numerals are given and the description thereof is omitted.

The protective belts 18 and 19 are in close contact with each other on the surface of the platen roller 12.
When 2 rotates, it rotates with each roller 25-28.
The protective belts 18 and 19 are prevented from falling off by the flanges 25b to 28b.

The movable bases 30 and 31 include guide rods 32 and
It is movably attached to 33. Guide rod 32,
Between 33, the drive shaft 3 driven by the motor 35
6 is provided. The drive shaft 36 is formed with two feed screws 36a and 36b having different lead directions, and the feed bases 36a and 36b are attached to the moving base 3.
The screws formed at 0 and 31 are screwed together.

When the motor 35 is driven to rotate the drive shaft 36 in the direction of the arrow, the moving bases 30 and 31 move in the direction of the arrow along the guide rods 32 and 33, so that the protective belts 18 and 19 move to the platen roller 12. It slides up and moves, widening the gap. Further, when the drive shaft 36 rotates in the direction opposite to the arrow direction, the interval between the protective belts 18 and 19 becomes narrow.

The protective belts 18 and 19 are as follows.
For example, polyethylene terephthalate or the like is used as the material. In addition, the heating element array 13a and the color thermosensitive recording paper 1
In order to make good contact with 0, an extremely thin material having a thickness of 0.1 mm or less is used. Protective belt 18,19
Are arranged at intervals slightly shorter than the paper width L of the color thermosensitive recording paper 10, and the end 10a of the color thermosensitive recording paper 10 is superposed on the protective belts 18 and 19 during printing. The interval between the protective belts 18 and 19 can be set steplessly within the range in which the moving bases 30 and 31 move the drive shaft 36, so that it is possible to cope with color thermosensitive recording paper of various paper width sizes.

The color thermosensitive recording paper 10 having a thickness of 0.20 to 0.25 mm is used, but since the protective belts 18 and 19 are extremely thin as described above, the color thermosensitive recording paper 10 overlaps. Almost no part becomes a step and rises. In addition, the color thermosensitive recording paper 10
Since the outside of the recording area of is overlapped on the protective belts 18 and 19, it does not affect the printed image.

While the protective belts 18 and 19 are rotating,
Although in contact with the heating element array 13a of the thermal head 12, the surfaces of the protective belts 18 and 19 are smoother than that of the platen roller 12, so the heating element array 13a is formed.
Is not scratched. A lubricant layer is preferably formed on the surfaces of the protective belts 18 and 19.

Before and after the thermal head 13, the emission peak is approximately 42 in order to optically fix the yellow thermosensitive coloring layer 6.
UV lamp 37 for yellow which emits UV of 0 nm
An ultraviolet lamp 38 for magenta, which emits ultraviolet rays having an emission peak of about 365 nm, is arranged to optically fix the magenta thermosensitive coloring layer 7. Each ultraviolet lamp 37,
38 is a rod-like shape, and the reflectors 39, 40 are behind them.
Are provided respectively.

The operation of the color thermal printer constructed as above will be described. When the switch is turned on according to the width of the color thermosensitive recording paper 10, this switch is turned on.
The motor 35 rotates during the period N. The drive shaft 36 is rotated by the motor 35, and the moving bases 30 and 31 move along the guide rods 32 and 33. Protective belt 1
Switch OFF when the interval between 8 and 19 is appropriate.
If F, the motor 35 stops. The moving base 3
The pulse motor is driven during the movement of 0 and 31, and the platen roller 12 is idly fed. Therefore, the protective belts 18 and 19 move smoothly on the surface of the platen roller 12 without being forcibly pulled. Protective belt 18,
19 is set at an interval slightly narrower than the paper width L of the color thermosensitive recording paper 10.

When the print start switch is turned on, the conveying roller pair 11 and the platen roller 12 start rotating clockwise. The color thermosensitive recording paper 10 is sent from a paper feed cassette (not shown). When the leading edge of the color thermosensitive recording paper 10 reaches the conveying roller pair 11, the color thermosensitive recording paper 10 is nipped by the conveying roller pair 11 and sent onto the platen roller 12.

The color thermal recording paper 10 is a platen roller 1.
When the temperature reaches 2, the both ends 10a of the color thermosensitive recording paper 10 ride on the protective belts 18 and 19. The recording area of the color thermosensitive recording paper 10 is the heating element array 13 of the thermal head 13.
Immediately before passing through a, the thermal head 13 is lowered and the heating element array 13a is pressed against the color thermosensitive recording paper 10. Since both ends of the heating element array 13a protruding from the color thermosensitive recording paper 10 are on the protective belts 18 and 19, it is possible to prevent the platen roller 12 from being directly contacted and damaged.

When the heating element array 13a reaches the recording area of the color thermosensitive recording paper 10, each of the heating elements is colored to a temperature in consideration of the coloring characteristic of the yellow thermosensitive coloring layer 6, and a yellow image is printed on the color thermosensitive recording paper 10. Heat is recorded line by line. When the portion of the color thermosensitive recording paper 10 on which the yellow image is thermally recorded reaches the yellow ultraviolet lamp 37, ultraviolet rays of about 420 nm are irradiated, and the yellow thermosensitive coloring layer 6 is optically fixed.

When the trailing edge of the color thermosensitive recording paper 10 reaches the carrying roller 11 after the recording of the yellow image is completed, the rotations of the carrying roller 11 and the platen roller 12 are once stopped. Next, the transport roller 11 and the platen roller 12 rotate clockwise, and the color thermosensitive recording paper 10 is transported in the opposite direction. During this conveyance, the thermal head 13 thermally records a magenta image line by line on the magenta thermosensitive coloring layer 7 of the color thermosensitive recording paper 10. When the portion of the color thermosensitive recording paper 10 on which the magenta image is thermally recorded reaches the magenta ultraviolet lamp 38, the ultraviolet rays of about 365 nm emitted from the magenta ultraviolet lamp 38 cause
The magenta thermosensitive coloring layer 7 is optically fixed.

After the optical fixing of the magenta thermosensitive coloring layer 56 is completed, the rotation directions of the conveying roller 11 and the platen roller 12 are switched again. And the color thermosensitive recording paper 1
A cyan image is thermally recorded while the recording area 0 is passing through the thermal head 13, and a full-color image is formed on the color thermosensitive recording paper 10 by three-color surface sequential recording.

FIG. 4 shows a case where the protective belts 51 and 52 are arranged at an interval equal to or slightly wider than the paper width L of the color thermosensitive recording paper 53. In this case, the protective belts 51 and 52 having a thickness of 0.15 to 0.25 mm are used. Heating element array 54 of thermal head 54
Since both ends of a are supported by the protective belts 51 and 52, contact between the platen roller 55 and the thermal head 54 is prevented. In this embodiment, the color thermosensitive recording paper 53 is used.
However, since it does not ride on the protective belts 51 and 52, a step does not occur.

The above embodiment is a 3-pass 1-head type color thermal printer, but it can be applied to a drum type color thermal printer for recording while recording the color thermal recording material on the platen drum. In addition to the 3-pass 1-head type, it can be applied to a 3-head 1-pass type color thermal printer. Further, all of the protective belt may be wound around the platen. In this case, the protective belt cannot move according to the paper width, but the structure is simple.

[0028]

As described above in detail, according to the present invention, the pair of protective belts are hung on the platen to receive both ends of the heating element array protruding from the heat-sensitive recording paper. Both ends of the element array do not come into contact with the platen to be damaged.

Further, since the pair of protective belts is movable in the axial direction of the platen according to the width of the thermal recording paper,
It can be used for thermal recording papers of various widths.

[Brief description of drawings]

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

FIG. 2 is a plan view showing the outline of a color thermal printer of the present invention.

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

FIG. 4 is an explanatory diagram showing an embodiment in which a gap between protective belts is set wider than a width of a color thermosensitive recording paper.

[Explanation of symbols]

 10 Color Thermal Recording Paper 12 Platen Roller 13 Thermal Head 13a Heating Element Array 18, 19 Protective Belt 53 Color Thermal Recording Paper 54 Thermal Head 54a Heating Element Array 55 Platen Roller

Claims (3)

[Claims] 1. A thermal head is arranged opposite to a platen roller, the heat-sensitive recording paper on the platen roller is pressed by a heat-generating element array of the thermal head, and the heat-sensitive element array heats the heat-sensitive recording sheet to convey an image. In a thermal printer for recording, a pair of protective belts are arranged in a state of being partially wound on both sides of the platen roller, and both ends of the heating element array protruding from both sides of the thermal recording paper do not contact the platen roller. As described above, the thermal printer is characterized in that it is supported by a pair of protective belts. 2. The thermal printer according to claim 1, wherein each of the protection belts is wound around two rollers in addition to the platen roller, and has a triangular shape when viewed from the side. . 3. The two rollers are flanged rollers that are movable in the axial direction of the platen roller, and the distance between the pair of protective belts can be changed according to the width of the thermal recording paper. The thermal printer according to claim 2, which is characterized in that.