JPH06238921A - Thermal printer - Google Patents

Abstract

PURPOSE:To obtain a thermal printer which can perform high-quality printing even on plain paper having low smoothness. CONSTITUTION:The thermal printer possesses a thermal head 8 heating a part of an ink sheet 1 corresponding to a pixel by receiving a printing signal electrifying the pixel which has excepted image information which is to record on recording paper, an ink sheet supply roll 2 supplying the ink sheet 1 to the thermal head 8 and a transferred sheet supply roll 13 conveying a transferred sheet 12. The printer is comprised of a heat roller 10 heating and transferring the ink sheet 1 after it has been transferred to the transferred sheet 12 to the recording paper 5 in addition to the above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer type thermal printer using an ink sheet, and in particular, a thermal printer capable of excellent printing even on inexpensive recording paper (hereinafter referred to as plain paper) having low surface smoothness. Regarding the printer.

[0002]

2. Description of the Related Art A conventional thermal printer will be described with reference to the drawings. FIG. 7 is a schematic explanatory diagram of a conventional thermal printer. The ink sheet 1 is supplied from the ink sheet supply roll 2, passes between the thermal head 8 and the platen roller 9, and is wound up by the ink sheet winding roll 4. The ink sheet winding roll 4 is rotated by a drive source (not shown) (for example, a motor) to wind up the ink sheet 1. The recording paper 5 passes between the ink sheet 1 and the platen roller 9, and is fed by a pair of paper feed rollers 6. The thermal head 8 is supported by the support shaft 7, is freely rotatable, and is urged downward in the drawing by the compression spring 3. Therefore, the ink application surface of the ink sheet 1 and the upper surface of the recording paper 5 are thermally It is pressed between the head 8 and the platen roller 9. Then, by applying a heat pulse corresponding to the input image signal to the thermal head 8, the ink is transferred to the recording paper 5. Then, by winding the ink sheet 1 around the ink sheet winding roll 4, the ink sheet 1 and the recording paper 5 are peeled off and an output image is obtained on the recording paper.

[0003]

In such a conventional thermal printer, since the printing quality depends on the surface smoothness of the recording paper, the surface has a high smoothness (Beck smoothness of several hundred seconds). I used recording paper. However,
The recording paper having such a high smoothness is expensive and costly. Further, when inexpensive low-smoothness recording paper (Beck smoothness of several tens of seconds), that is, plain paper, is used, it is extremely inconvenient because ink transfer defects called ink bleeding frequently occur and printing quality remarkably deteriorates.

[0004]

In order to solve the above problems, a thermal printer according to the present invention receives a print signal for energizing a pixel excluding image information to be recorded on a recording sheet and responds to the pixel. First heating means for heating a portion of the ink sheet, an ink sheet supply means for supplying the ink sheet to the first heating means, and the ink of the ink sheet melted by the first heating means is transferred. Transfer sheet conveying means for conveying the transfer sheet, and
The ink sheet after being transferred to the transfer sheet is heated and is transferred to the recording paper by a second heating unit.

[0005]

In the thermal printer configured as described above, in the first printing step, non-print pixels other than the ink portion (hereinafter, simply referred to as print pixel) transferred to the recording paper corresponding to the output image are printed. The corresponding ink portion is transferred from the ink sheet to the transfer target sheet.

Next, as a second printing step, the output image is obtained by transferring the ink of the ink sheet in which only the ink portion corresponding to the printing pixel remains after the completion of the first printing step to the recording paper.

The reason for this is that the plain paper has low surface smoothness and therefore has surface irregularities, and ink cannot contact the recesses and transfer cannot be performed, so that ink transfer is insufficient and scrapes or dropouts occur. Therefore, an object of the present invention is to provide a thermal printer which can obtain a good recorded image even if an inexpensive plain paper is used as the recording paper, and is inexpensive and easy to use.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory diagram of a first embodiment of the present invention. In this embodiment, a transfer type thermal printer using an ink sheet using hot melt type ink will be described.

The ink sheet 1 is formed by coating a PET (polyethylene terephthalate) sheet as a base material with hot melt type ink which is melted by heating and wound around an ink sheet supply roll 2. Ink sheet 1
Is supplied from the ink sheet supply roll 2, passes between the thermal head 8 and the platen roller 9 which are the first heating means, and further passes between the heat roller and the platen roller 11 which is the second heating means 10 to wind the ink sheet. Take roll 4
To be wound up.

The ink sheet take-up roll 4 is rotated by a drive source (not shown) (a DC motor in this embodiment) to wind up the ink sheet 1. Transferred sheet 1
2 is wound around the transfer sheet supply roll 13, passes between the ink sheet 1 and the platen roller 9, and is wound up by the transfer sheet take-up roll 14. The transfer sheet winding roll 14 is rotated by a drive source (not shown) (a pulse motor in this embodiment) to wind the transfer sheet 12.

The transfer-receiving sheet 12 is one that can transfer ink well, and preferably has a high surface smoothness and a good affinity (wettability) with ink, for example, coated paper, printing paper, PET film. Etc. In this example, a printing paper (having a surface Bekk smoothness of 400 seconds) was used.

The thermal head 8 is supported by the support shaft 7 and is freely rotatable, and is biased downward in the drawing by the compression spring 3. Therefore, the ink application surface of the ink sheet 1 and the transfer-receiving sheet 12 are separated. The upper surface is pressed between the thermal head 8 and the platen roller 9.

Then, by applying the heat pulse corresponding to the non-printing pixel to the thermal head 8 while feeding the transfer sheet 12, the ink corresponding to the non-printing pixel is transferred to the transfer sheet 12. In this way, when the first printing process is completed, only the ink corresponding to the print pixels remains on the ink sheet 1, and the ink corresponding to the non-print pixels is transferred to the non-transfer sheet 12.

In the next second printing step, the recording paper 5 passes between the ink sheet 1 and the platen roller 11 and is fed by a pair of paper feed rollers 6. Since the heat roller 10 is biased downward in the drawing by the compression spring 15, the ink application surface of the ink sheet 1 and the upper surface of the recording paper 5 are pressed between the heat roller 10 and the platen roller 11. Then, the heat of the heat roller 10 transfers the ink to the recording paper 5. After that, the ink sheet 1 and the recording paper 5 are peeled off, and an output image is obtained on the recording paper 5.

Here, since the ink sheet 1 has only ink corresponding to the print pixels, all the ink of the ink sheet 1 may be transferred to the recording paper 5. Therefore, since the second heating means does not have a function of selectively heating to correspond to the print pixels unlike the thermal head, the heat roller is used in this embodiment.

As is well known, the heat roller has a hollow cylinder having a good heat conductivity such as an aluminum material, which is covered with a heat-resistant and elastic material such as silicon rubber on the outer circumference of the cylinder. In addition, a heat source such as a halogen lamp is provided. Now, the transfer state of the ink when the second printing process is performed as described above will be described with reference to FIG.

In the conventional thermal printer, as shown in FIG. 2A, when the ink is transferred, the ink corresponding to the printing pixel and the non-printing pixel, that is, the melted ink 1a.
And the unmelted ink 1a coexists. Therefore, since the originally melted ink 1a is softened and can be transferred by being in contact with the surface unevenness of the recording paper 5, the unmelted ink 1b is hardened and thus the recording paper 5
Can only come into contact with the protrusions on the surface. Therefore, the melted ink 1a is affected by the unmelted ink 1b, and the recording paper 5
In the recording paper having a low smoothness, it was possible to make contact with only the convex portions on the surface, and printing defects such as ink bleeding and blurring occurred.

However, in the present invention, as shown in FIG. 2 (b), since only the ink corresponding to the print pixel exists in the ink sheet 1 in the second printing step, that is, only the melted ink 1a exists, the ink Can be intimately contacted with the surface irregularities of the recording paper 5, and good ink can be transferred onto plain paper.

Next, a second embodiment of the present invention will be described with reference to FIGS. This embodiment also comprises a first printing step and a second printing step, but each step has a different feature from the first embodiment and will be described. Also,
Although the same configuration and operation as those of the first embodiment are performed, the description thereof will be omitted.

First, the transfer sheet 12 will be described. The transferred sheet 12 is the ink sheet 1 as shown in FIG.
Along with it, it is wound around the ink sheet supply roll 2. The transferred sheet 12 and the ink sheet 1 are supplied from the ink sheet supply roll 2 and pass between the thermal head 8 which is the first heating means and the platen roller 9. The transferred sheet 12 is fed by a pair of sheet feeding rollers 17.

Further, the ink sheet 1 passes between the thermal head 20 which is the second heating means and the platen roller 11 and is wound up by the ink sheet winding roller 4.

The recording paper 5 is fed by the pair of paper feed rollers 6 passing between the ink sheet 1 and the platen roller 11. Then, in the first printing step, the ink corresponding to the non-printed pixels of the ink sheet 1 is transferred to the transfer target sheet 12 by the thermal head 8 which is the first heating means, and further as the second printing step, the second heating means. Thermal head 20
Then, the ink corresponding to the print pixels remaining on the ink sheet 1 is transferred to the recording paper 5 to obtain an output image.

Here, since the transfer sheet 12 is wound around the ink sheet supply roll 2 together with the ink sheet 1, the transfer sheet supply roll 13 is unnecessary as in the first embodiment, so that the apparatus is not used. The feature is that it can be downsized. Further, the transferred sheet 12 is the sheet feed roller 1
After sending in 7, it is stored in the device or discharged to the outside of the device. That is, the transfer sheet take-up roll 14 used in the first embodiment is not necessary, so that the apparatus can be downsized.

Further, in this embodiment, a thermal head was used as the second heating means. That is, in the first embodiment, since the heat roller is used as the second heating means, warm-up time (time to heat the heat roller to a temperature necessary for melt transfer of ink) is required, and printing time is required. It takes a long time. On the other hand, the thermal head has a characteristic that the printing time can be shortened because the warm-up time is unnecessary.

Next, a third embodiment of the present invention will be described with reference to FIGS. This embodiment also comprises a first printing process and a second printing process, but each process has different features from the first and second embodiments and will be described. The description of the same configurations and operations as those of the first embodiment will be omitted.

The ink sheet 1 is covered with an ink sheet supply roll 2 and passes between a thermal head 8 as a first heating means and a platen roller 9 to be wound up on an ink sheet winding roll 4. The transferred sheet 12 is an endless sheet that passes between the ink sheet 1 and the platen roller 9 and is stretched around the platen roller 9 and the tension roller 18.

First, the first printing process will be described based on item 5. The surface (arrow B) of the transferred sheet 12 and the ink sheet 1 are opposed to each other. During the first printing process, there is no opening A (see FIG. 6B) between the thermal transfer sheet 8 and the platen roller 9 so that only the ink sheet 1 and the transferred sheet 12 are present. Use surface B.

By applying heat pulses corresponding to non-print pixels other than the print pixels to the thermal head 8 while feeding the transfer sheet 12 and the ink sheet 1, ink corresponding to the non-print pixels is transferred to the transfer sheet 12. Is transcribed to.
Thus, when the first printing process is completed, only the ink corresponding to the print pixels remains on the ink sheet, and the ink corresponding to the non-print pixels is transferred to the transfer target sheet 12.

Next, the second printing process will be described with reference to FIG. The recording paper 5 is inserted between the feed ink sheet 1 and the platen roller 9 by a pair of paper feed rollers 6. At this time, in order to bring the recording paper 5 and the platen roller 9 into pressure contact with each other, the transfer target sheet 12 is fed so that the opening (arrow A) of the transfer target sheet 12 faces the recording paper 5. Opening A
Has a width and a length such that the recording paper 5 contacts the platen roller 9 and does not contact the transfer target sheet 12, and the ink sheet 1 is recorded between the thermal head 8 and the platen roller 9 during the second printing process. Only the paper 5 is present and the transferred sheet 12 is absent.

Then, while the ink sheet 1 and the recording paper 5 are being fed, the heat of the thermal head 8 causes the ink of the ink sheet 1 having only the ink corresponding to the print pixel to be transferred to the recording paper 5.
Transfer to. After that, the ink sheet 1 and the recording paper 5 are peeled off, and an output image is obtained on the recording paper 5.

Here, the transfer onto the recording paper 5 may be performed by rewinding the ink sheet 1 onto the supply roll 2, or the rewinding of the ink sheet 1 by a predetermined amount before the transfer onto the recording paper 5. You may transfer it after saving it. The drawing of the rewinding mechanism of the ink sheet 1 is omitted.

Here, the first heating means uses a thermal head which also serves as the second heating means, so that each of the first and second printing steps is performed as in the first and second embodiments. Since no heating means is required, the number of parts of the device is reduced, and the device is inexpensive and compact.

In each of the embodiments of the present invention, the print sheet is used as the transfer sheet, but the transfer sheet is not limited to the print sheet, and a material having good transferability (wettability) with ink may be selected. Needless to say. For example, PET sheets and coated paper with high smoothness are examples thereof.

In each of the embodiments of the present invention, the transfer sheet is a roll-shaped sheet or an endless sheet, but the transfer sheet is not limited to these, and cut sheets may be sequentially used. Good. Further, in each of the embodiments of the present invention, the number of times the transfer target sheet is used is not limited, and the transfer sheet may be used only once or may be used repeatedly a plurality of times.

Needless to say, in each of the embodiments of the present invention, the ink sheet and the kind are not limited. For example, an ink sheet of a single color or a plurality of colors, a melt type ink, a sublimation type ink, or the like is used.

[0036]

As described above, the present invention provides a high-quality thermal printer capable of obtaining a good recorded image without causing ink loss or blurring even on inexpensive recording paper having a low surface smoothness. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment relating to a thermal printer of the present invention.

FIG. 2A is an explanatory view showing a transfer state of ink in a conventional thermal printer, and FIG. 2B is an explanatory view showing a transfer state of ink in the thermal printer of the present invention.

FIG. 3 is an explanatory diagram of a second embodiment relating to the thermal printer of the present invention.

FIG. 4 is an explanatory diagram of an ink sheet supply roll in a second embodiment relating to the thermal printer of the present invention.

FIG. 5 is an explanatory diagram of a third embodiment relating to the thermal printer of the present invention.

FIG. 6 is an explanatory diagram of a third embodiment relating to the thermal printer of the present invention.

FIG. 7 is an explanatory diagram of a conventional thermal printer.

[Explanation of symbols]

 1 Ink Sheet 5 Recording Paper 8 and 20 Thermal Head 10 Heat Roller 12 Transferred Sheet

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 9305-2C 117 Z

Claims (3)

[Claims] 1. A transfer type thermal printer for transferring ink of an ink sheet to a recording paper by heating, receiving a print signal for energizing a pixel excluding image information to be recorded on the recording paper, and ink corresponding to the pixel. First heating means for heating a portion of the sheet, ink sheet supply means for supplying the ink sheet to the first heating means, and ink to which the ink of the ink sheet melted by the first heating means is transferred. A thermal transfer device, comprising: a transfer sheet conveying unit that conveys a transfer sheet; and a second heating unit that heats the ink sheet after being transferred to the transfer sheet and transfers the ink sheet to the recording sheet. Printer. 2. The ink sheet supply means has a rewinding mechanism, and the first heating means and the second heating means can be used together by one heating means. Item 2. The thermal printer according to Item 1. 3. The thermal printer according to claim 1, wherein the transfer target sheet is supplied from a roll wound together with the ink sheet.