JPH05305723A - Thermal head for thermal transfer printer - Google Patents

Abstract

PURPOSE:To improve the quality of thermal transfer recording by a method wherein the heating part of each of resisting elements is divided into a plurality of sections for a single picture element (one dot) to control the effect of the characteristic variation of each resisting element to the minimum possible extent. CONSTITUTION:The heating part of each of a number of resisting elements 11 arranged on a thermal head 4 is divided into four sections, whereby the effect of the characteristic variation of each resisting element 11 is controlled in its entirety to the minimum possible extent and whereby the thermal transfer recording insusceptible to a great effect of the characteristic variation of each resisting element becomes possible to a satisfactory extent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head in which a large number of resistance elements are arranged for use in a sublimation type thermal transfer color printer.

[0002]

2. Description of the Related Art For example, a sublimation type thermal transfer type color printer is known in which the heat generated by a large number of resistance elements arranged in a thermal head is used to thermally transfer and record ink on an ink film onto a printing paper. In this sublimation type thermal transfer color printer, one resistance element thermally records one dot (one pixel). In order to print a color image, three color ink films of yellow (Y), magenta (M), and cyan (C) each having a size of one screen are overlaid for thermal transfer recording. Further, this sublimation type thermal transfer type color printer can finely control the density (gradation) by changing the amount of ink adhered for each dot in a wide range. In other words, it is widely adopted because it can express a subtle color tone without lowering the resolution.

[0003]

However, in the conventional sublimation type thermal transfer color printer described above, as shown in FIG. 4, one heat generating portion H of one resistance element per pixel is used.
Therefore, when the concentration is changed, the maximum concentration and the minimum concentration are likely to vary due to the characteristic variation of the heat generating portion H of each resistance element. That is,
Even under the same conditions, thermal transfer recording was likely to have shading. For this reason, when thermal transfer recording is performed on a monotonous image having gradation such as gradation, horizontal stripes (lines) are conspicuous in the main scanning direction, that is, the printing paper feed direction of the platen roller. It should be noted that although the horizontal stripes cannot be controlled by controlling the applied current or the like, it was not easy to find the correspondence between the horizontal stripes of thermal transfer recording (printing) and the corresponding heat generating portion H of each resistance element.

Therefore, according to the present invention, by subdividing the heat generating portion of the resistance element into a plurality of pixels per pixel, it is possible to suppress the influence of the characteristic variation of each resistance element as much as possible and perform good thermal transfer recording. A thermal head of a thermal transfer printer is provided.

[0005]

In a thermal head of a thermal transfer printer in which ink on an ink film is heat-transfer-recorded on a printing paper by utilizing heat generation of a resistance element, the heat-generating portion of the resistance element is divided into a plurality of parts. I am doing it.

[0006]

[Function] Since the heat generating portion of the resistance element is divided into a plurality of parts,
A plurality of heat generating units correspond to one pixel (one dot).
As a result, the average value of each resistance element appears in thermal transfer recording,
At the time of thermal transfer recording, the influence of the characteristic variations of the resistance elements is totally suppressed as much as possible, and the quality of thermal transfer recording is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, 1 is a sublimation type thermal transfer color printer, 2 is a casing type printer main body, 3 is a platen roller, 4 is a thermal head, 5 is a paper feed roller, 6 is a paper feed guide, and 7a ... 7c is a pinch roller, 8 is a paper discharge roller, 9 is a printing paper, and 10 is an ink film.

A large number of resistance elements 11 are arranged on the upper surface side of the thermal head 4. The heat generating portion 11a of each resistance element 11 is divided into four as shown in FIG. As a result, one heating element 11a, 11a, 11a, 11a corresponds to one dot (one pixel). The ink film 10 is wound around a pair of reels 10a and 10b for supplying and winding. Furthermore, this sublimation type thermal transfer type color printer 1
Are controlled by the system configuration diagram (circuit block diagram) shown in FIG. That is, the video signal input from the video input terminal is converted into a digital signal by the A / D converter 12. This digital signal is taken into the RGB frame memory 13, and after the data is subjected to processing such as halftone and line interpolation via the line memory 14, it is sent to each resistance element 11 of the thermal head (thermal line head) 4. These processes are controlled by the digital section control 15. A motor 16 for rotating the platen roller 3 and a motor 17 for driving the paper feed roller 5, each of the pinch rollers 7a to 7c, etc. are controlled by a system control 18 and a servo section 19.

According to the sublimation type thermal transfer type color printer 1 of the above embodiment, the printing paper 9 sent out by the paper feed roller 5 is used.
Is guided by the pinch rollers 7a to 7c and wound around the platen roller 3. The ink film 10 and the platen roller 3 rotate on the thermal head 4 without being displaced by rotating in synchronization with each other by one pitch for each pixel. In this way, the thermal transfer recording of the yellow (Y), magenta (M), and cyan (C) inks on the ink film 10 is repeated three times via the resistance elements 11 of the thermal head 4, thereby completing the color printing.

Since the heating portion 11a of each resistance element 11 is divided into four parts for one pixel (one dot),
As shown in FIG. 2A, four heat generating portions 11a can be associated with one pixel. That is, the influence of the characteristic variation of each resistance element 11 can be suppressed as much as possible by simultaneously driving the four heat generating portions 4a of each resistance element 11. As a result, when a monotonous and gradational color image is thermally transferred and recorded by the sublimation thermal transfer type color printer 1, horizontal stripes are not conspicuous in the feeding direction of the printing paper 9 of the platen roller 3 as in the conventional case. The quality of color prints can be further improved. Further, by applying density modulation to each resistance element 11 and simultaneously changing the number of thermal transfer recordings (printing quantity) of each resistance element 11, as shown in FIG. it can.

As described above, the resistance element 11 is provided for one pixel.
Since the heat generating portion 4a of 4 is subdivided into four, variations in pixels are compressed. In addition, since the pixel variation is compressed, no correction is required. Furthermore, since the four heat generating portions 4a of the resistance element 11 correspond to the drive of one pixel,
For example, driving with one element is advantageous for driving light pixels. As a result, the dynamic range (that is, gradation) becomes large.

Although the thermal head used in the sublimation type thermal transfer type color printer has been described in the above embodiment, it may be applied to a thermal head used in various color printers such as a fusion type thermal transfer type color printer. .

[0014]

As described above, according to the present invention, in the thermal head of the thermal transfer printer in which the ink on the ink film is thermally transferred and recorded on the printing paper by utilizing the heat generated by the resistive element, Since the heat generating portion is divided into a plurality of portions, a plurality of heat generating portions are associated with one pixel so that the average value of each resistance element appears in the thermal transfer recording. As a result, it is possible to suppress the influence of the characteristic variations of the respective resistance elements as much as possible, and it is possible to further improve the quality of thermal transfer recording.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sublimation type thermal transfer color printer according to an embodiment of the present invention.

FIG. 2A is an explanatory view showing a relationship between a heating portion of a resistance element of a thermal head used in the printer and a density of thermal transfer recording, and FIG. 2B is a heating portion of the resistance element of the thermal head and a density and a floor. Explanatory drawing which shows the relationship of a key.

FIG. 3 is a circuit block diagram showing a system configuration used in the printer.

FIG. 4 is an explanatory diagram showing a relationship between a heating portion of a resistance element of a conventional thermal head and a density of thermal transfer recording.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thermal transfer color printer 4 ... Thermal head 9 ... Printing paper 10 ... Ink film 11 ... Resistor element 11a ... Heat generating part

Claims (2)

[Claims] 1. A thermal head of a thermal transfer printer in which ink on an ink film is thermally transferred and recorded on a printing paper by utilizing heat generated by a resistance element, wherein a heat generating portion of the resistance element is divided into a plurality of parts. A thermal head for a thermal transfer printer. 2. The thermal head of the thermal transfer printer according to claim 1, wherein the heat generating portion of the resistance element is divided into four parts.