JPS6094393A - Transfer paper for thermal transfer printing - Google Patents

Abstract

PURPOSE:To obtain a beautiful desired color-printed face free of color shift by providing plural colors of heat-meltable inks in a striped form in nearly parallel with the direction of thermal transfer printing on a transfer paper base. CONSTITUTION:Heat-meltable inks of red, yellow, and blue colors for example are screen-printed in a striped form in nearly parallel with the direction of printing by repeating lines 12a, 12b, and 12c with the same width (or 250/3mum) as the density of a picture element of pictures displayed on the fluorescent face of a television, for example, on one side of a base 11, e.g., transparent polyester film, etc. The lines 12a, 12b, and 12c sides of the heat-meltable inks on the transper paper 10 are lapped on the recording face side of a recording paper 21 and sent between a platen roller 22 and a serial thermal heat 15, and current corresponding to picture signal of television flows in the heating resistor 16 and thermal transfer printing is made.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to color hard copy devices that employ a thermal transfer printing method, such as for VTRs, personal computers, facsimile machines, and word processors. Regarding transfer paper for thermal transfer printing, heat-melting ink of multiple colors is provided on the transfer paper base in a stripe shape approximately parallel to the printing direction of thermal transfer printing, so that thermal transfer can be performed using such transfer paper. It is an object of the present invention to provide a transfer paper for thermal transfer printing, which provides an excellent color image when printed.

[Prior art]

The principle of thermal transfer printing is as shown in FIG. When the transfer paper 2 is heated by passing an electric current through the heat generating resistor and heating the transfer paper 2, the heat-melting ink 2' applied to the transfer paper 2 at a constant thickness melts and is applied to the recording paper 1. The heat-melting ink 2' is attached to the recording paper, which has been transferred and printed in this way, and is then anodized into an appropriate shape to become a printed matter.The unnecessary transfer paper passes through a guide roller and is wound around a take-up roller. It would be removed and disposed of.

The transfer paper 2 used in such thermal transfer printing is, for example, in the case of color printing using the three primary colors of red, yellow, and blue, as shown in Figure 2.
When printing on a size paper 1c, for example, hot-melt ink containing coloring agents such as red, yellow, and blue is repeatedly applied in order on the transfer paper base surface having a width of 216 mm every 297 mm in length.

After performing the first color thermal transfer printing using, for example, the area coated with red heat-fusible ink, the recording paper on which red dots have been formed is returned to its original position, and then yellow heat-fusible ink is applied. Use the part where the ink is applied to make the second
Color printing can be achieved by performing thermal transfer printing for a color, and then performing thermal transfer printing for a third color using the area coated with the blue heat-melting ink.

It is difficult to express a complete black color using a combination of red, yellow, and blue, so red, yellow, blue, and black inks are used in inkjet systems, for example, but thermal transfer When it comes to printing methods, it's all about printing time and running costs! Since most cases use 113 primary colors, the case using three primary colors will be described below.

Therefore, even when the transfer paper is constructed using four colors such as red, yellow, blue, and black, the same holds true as when using three primary colors.

[Problems with conventional technology]

When performing color printing using the thermal transfer printing method as described above, thermal transfer is performed multiple times such as the first color, second color, and third color. Color misregistration inevitably occurs due to unavoidable accuracy problems. For example, if the recording paper on which the first color thermal transfer printing was performed is returned to its original state and a second color heat-melt ink area is used. When performing thermal transfer printing for the second color, if the recording paper and the transfer paper are not perfectly aligned, even a slight misalignment will cause color misregistration. The colors available are limited and the desired color cannot be expressed, and it is not particularly suitable for printing images that require precise shading.

However, as mentioned above, although there are major drawbacks to color printing using the conventional thermal transfer printing method, the thermal transfer printing method has a faster recording speed than the inkjet method.
It is superior in the performance and maintainability required of recording paper, and inkjet printing has basic problems such as nozzle clogging, making it significantly inferior to thermal transfer printing in terms of maintainability. It has been highly desired that the above-mentioned problem be solved in the case of color printing using a thermal transfer printing method.

[Means for solving problems]

For example, a transfer paper with heat-melting ink of red, yellow, and blue applied on a base in stripes at approximately the same pixel density as the image projected on the fluorescent surface of a television is used, and a thermal transfer printing device is used. On the thermal bed side, a photodiode is installed with a color filter deposited on its light-receiving surface that allows only one of red, yellow, or blue to pass through, for example, red, to read the red heat-fusible ink line and perform thermal transfer printing. If you do this, there will be no misalignment and you will be able to print beautiful images.

〔Example〕

FIG. 3 is an explanatory diagram of one embodiment of the transfer paper for thermal transfer printing according to the present invention.

In the figure, 10 is a transfer paper, 11 is a base of the transfer paper 1o, such as a transparent polyester film, and the pixel density of an image projected on one surface of this base 11, for example, on the fluorescent surface of a television. the same density as, i.e. 250/
Red, yellow, and blue heat-melting ink lines 1 within 3 μm
2a, 12b, and 1.2c are screen printed repeatedly to form a stripe pattern parallel to the printing direction.

[Thermal head for thermal transfer printing using the transfer paper of the above example]

FIG. 4 is an explanatory diagram of the configuration of a thermal head incorporated in the printing apparatus when thermal transfer printing is performed using the transfer paper shown in FIG. 3.

In the figure, 15 is a serial thermal head, 16 is a heat generating resistor, and this heat generating resistor 16 is 125 μm x 1
They are provided at dot positions in 7 rows and 6 columns in a 25 μm area.

17 is a color filter that is provided, for example, on the line extension of the first row of the heating resistor 16 and that transmits only red.
This is a color sensor made of a photodiode (Si thin film) with , vapor-deposited on its light-receiving surface.

[Color printing using the above transfer paper in a thermal transfer printing device equipped with the above thermal head] FIG. 5 is an explanatory diagram of the principle of color printing using the transfer paper according to the present invention.

In the same figure, the same numbers as in FIGS. 3 and 4 indicate the same structure, and 21 is recording paper, and transfer paper 1
0 hot melt ink lines 12a, 12b.

The 12G side is overlapped with the recording surface side of the recording paper 21 and fed between the platen roller 22 and the serial thermal head 15, and a current corresponding to the television video signal is applied to the heating resistor 16 of the serial thermal head 15. The heat-melt ink is melted and thermal transfer printing is performed.

During this thermal transfer printing, the serial thermal head 1
5 is carried out by moving in a direction perpendicular to the thermal transfer printing direction indicated by the arrow by a head feeding mechanism 23, but this serial thermal head 15 is always moved by a color sensor 17 to print a line 12 of red heat-fusible ink.
Since position regulation is performed by detecting a, positional deviation does not occur and a perfect image can be obtained.

The shading of colors is achieved by applying spatial modulation and changing the ratio of white to colored areas using a halftone method.

〔effect〕

Thermal transfer printing method allows you to obtain beautiful color prints with the desired colors and no color shift.

Moreover, since this color print image is obtained by a thermal transfer printing method, the cost is lower than that by an inkjet method.

In addition, in thermal transfer printing, after the conventional thermal transfer printing with the first color heat-melt ink is completed, thermal transfer printing with the second color heat-melt ink, and sensitivity transfer with the second color heat-melt ink are completed. After thermal transfer printing is completed, it does not take more than three times as long as black and white printing, such as thermal transfer printing using a third color heat-melting ink, and the time required for color printing can be shortened. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of thermal transfer printing, Fig. 2 is an explanatory diagram of a conventional transfer paper, Fig. 3 is an explanatory diagram of an embodiment of the transfer paper for thermal transfer printing according to the present invention, and Fig. 4 is an explanatory diagram of the principle of thermal transfer printing. 5 is an explanatory diagram of a thermal head, and FIG. 5 is an explanatory diagram of thermal transfer printing using the transfer paper for thermal transfer printing according to the present invention. 10... Transfer paper, 11... Base, 12a, 1
2b, 12C... line of heat-melting ink. Patent Applicant: Victor Japan Co., Ltd. Agent: Katsuyuki Utaka

Claims (1)

[Claims] A transfer paper for thermal transfer printing, characterized in that heat-melting inks of multiple colors are provided on a transfer paper base in the form of stripes substantially parallel to the printing direction of thermal transfer printing.