JPS58208077A - Heat transfer type printing apparatus - Google Patents

Abstract

PURPOSE:To make it possible to render the area of a heat meltable ink transferred to recording paper continuously adjustable, by a method wherein a heat generating temp. is made changeable according to the place of a heat generating resistor and a current flowed through the heat generating resistor is controlled. CONSTITUTION:A heat transfer type printing apparatus is constituted, for example, in such a mechanism that temp. distribution generated by the heat generation of a resistor through which a current is supplied is highest at the center part thereof and lowered toward the periphery thereof in a concentrically circular form. When a current is flowed through the heat generating resistor so as to form the temp. distribution shown by the one-dot broken line of the drawing (b), a part bringing the temp. of a heat meltable ink to the m.p. or more thereof comes to the part within a circle encircled by the one-dot broken line of the drawing (a) and, when a current is passed through said resistor so as to form the temp. distribution shown by the two-dot broken line of the drawing (b), a part bringing the temp. of the heat meltable ink to the m.p. or more comes to the part within a circule encircled by the two-dot broken line of the drawing (b). Only by controlling a currnt flowed through the heat generating resistor, the area of the heat meltable ink transferred to recording paper can be made continuously adjustable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer printing device, and relates to a thermal transfer printing device in which the FJO heat generated in a thermal head is not constant and varies depending on the location. By making it possible to freely vary the amount of melted area of printing ink by the thermal head, the area gradation recording method can be made into a recording method with continuous gradation changes, which can be used for recording, for example, television image signals, etc. A. An object of the present invention is to provide a thermal transfer printing device that can improve resolution in printing records that are pale.

As shown in FIG. 1, the principle of a thermal transfer type printing device is that a recording paper 1 and a transfer paper 2 are brought into close contact with each other, and a pressure roller 3 is used.
and the heat-sensitive head 4, and a current is passed through each heat-generating resistor of the heat-sensitive head 4 to cause each heat-generating resistor to generate heat.
When the transfer paper 2 is heated, the hot-melt ink 2', which is coated with a constant thickness like a picture paper, melts, and the hot-melt ink 2' is attached to the recording paper 1. The printed recording paper is cut into a suitable shape to become a printed matter, and the unnecessary transfer paper is disposed of by passing through a guide roller and being wound up by a take-up roller.

For example, when a unit area is divided into 4 rows and 4 columns as shown in FIG.
By filling in the numbers in ascending order, the specified a
Area gradation recording using a dither matrix has been proposed, but it is difficult to increase the number of gradations, and therefore the resolution of print recording is inferior. There are drawbacks such as:

The present invention eliminates the above-mentioned drawbacks, and embodiments thereof will now be described.

That is, as the principle was described in Fig. 1, recording paper and transfer paper are placed in close contact with each other and are fed between a pressure roller and a thermal head, and a current is passed through each heat generating resistor of the thermal head to generate heat. The heat-melting ink coated to a certain thickness on the transfer paper is melted by heating the transfer and paper resistors by generating heat, and the melted heat-melt ink is attached to the recording paper. In an apparatus for printing using a heat sensitive head, the heat generating resistor 10 of the thermal head is configured to have a square shape, for example, as shown in FIG. 3a.

By configuring the heat generating resistor in this way, when a current is passed through the heat generating resistor, the temperature distribution generated by the heat generated by the resistor will not be uniform regardless of the location, but will be distributed in the center. is the highest, and decreases as it approaches the periphery in a concentric circle from the center, and when the temperature is shown in the Z-axis direction with respect to the XY plane, it shows a conical temperature distribution perpendicular to the XY plane. Therefore, the heat applied to the heat-melting ink on the transfer paper is highest at the center of the heat-generating resistor and falls concentrically, making it difficult to control the current flowing through the heat-generating resistor. Ba,
It is possible to freely change the range of temperature distribution caused by the heating resistor for ink melting.

For example, if a current is passed through a heating resistor so that the temperature distribution is as shown by the dashed line in Figure 3,
The part where the temperature is higher than the melting point of the hot-melt ink is the part within the circle surrounded by the dashed-dotted line in Figure 3a, and when a current is further applied, the temperature distribution is as shown by the dashed-double line in Figure 3a. In this case, the current flowing through the heating resistor is controlled so that the area where the temperature is higher than the melting point of the hot-melt ink is the area within the circle surrounded by the two-dot chain line in Figure 3a. The area of the hot-melt ink transferred to the recording paper can be continuously and variably adjusted using the press only. Therefore, instead of the conventional area gradation recording with a small number of gradations, it becomes an infinite area gradation recording that can be freely changed by controlling the current, and the resolution can be greatly improved. .

In the above embodiment, a case has been described in which the temperature distribution changes concentrically, but it may also change, for example, in a circular pattern.

As described above, the thermal transfer printing device according to the present invention melts the ink applied to the transfer paper by passing a current through the heat generating resistor of the thermal head and increasing the temperature of the heat generating resistor. A thermal transfer printing device that transfers images onto recording paper is configured so that the heat generation temperature changes depending on the location of the heat generating resistor, and the amount of melted ink is controlled by controlling the current applied to the heat generating resistor to produce color per exposed area. Since the density is controlled, area gradation recording has an extremely large number of gradations that can be freely changed according to the current flowing through the heating resistor, and the resolution is significantly improved. have

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of a thermal transfer type printing device, Fig. 2 is an explanatory diagram of gradation recording using a dither matrix, and Fig. 3a is an explanatory diagram of a heating resistor of a thermal transfer type printing device according to the present invention. , the same figure is an explanatory diagram of temperature distribution. 10... Resistor for heat generation. Patent applicant: Katsumi Utaka, agent of Victor Japan Co., Ltd.

Claims (1)

[Claims] In a thermal transfer printing device that melts the ink applied to the transfer paper and transfers it to the recording paper by passing a current through the heat generating resistor of the thermal head and increasing the temperature of the heat generating resistor, the heat generating resistor is used. Thermal transfer printing is characterized in that the heat generation temperature changes depending on the location on the body, and the amount of melted ink is controlled by controlling the current applied to the heat generating resistor, thereby controlling the color density per unit area. device 0