JPS60219093A - Heat transfer ink sheet - Google Patents

Abstract

PURPOSE:To provide a heat transfer ink sheet enabling area modulation of picture elements according to impressed energy and capable of outputting images such as full-color hard copies with high quality, comprising a thermoplastic ink layer and a metallic layer. CONSTITUTION:The thermoplastic ink layer 303 and the metallic layer (e.g., Al or Au) 302 are provided on a base layer (e.g., a condenser paper) 301 to obtain the desired heat transfer ink sheet.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is used in a thermal transfer type printing device that applies thermal energy to activate and activate thermoplastic ink and transfer it to a transfer medium to obtain characters and images. The present invention relates to a thermal transfer ink sheet.

[Prior art]

2. Description of the Related Art As full-color hard copy devices for images, thermal transfer printers, inkjet printers, and the like have been developed and commercialized.

Thermal transfer printers are superior in terms of miniaturization, low cost, easy maintenance, clear images, and tamperability.

However, basically, thermal transfer printers can only display dots in binary values (1 or 0) when considering reproducibility.
In order to produce gradations with full color support, a method is adopted in which each 1i# element is represented by a plurality of dots using a concave gradation method such as a density pattern method or a dither method. However, this method has a drawback that as the number of floors ii'4 increases, one pixel becomes larger and the resolution power ζ decreases.

〔the purpose〕

The present invention improves the above-mentioned drawbacks, and by improving the ink sheet, the pixel diameter can be changed depending on the recording energy.
! An object of the present invention is to provide an ink sheet that enables modulation and outputs high-quality full-color hard copies.

〔overview〕

That is, the present invention provides a thermal transfer ink sheet used in a thermal transfer type printing device that applies thermal energy to activate the thermoplastic ink and transfer it to a transfer medium to obtain characters/images. The details of providing a thermal transfer ink sheet characterized by having a metal layer and a metal layer will be described below.

FIG. 1 shows a schematic diagram of a conventional thermal transfer type printing device. In the figure,
101 is a thermal head, 102 is a base film such as PIT or condenser paper, 103 is a thermoplastic ink layer, and 104 is an ink sheet. When a voltage pulse (105) is applied to the thermal head, the head generates heat and a part of the ink layer (10/) is melted by heat conduction.
Transfer to a transfer medium (107).

In the conventional method, the reproducibility is good and the dot diameter modulation is very far away.

The second IAα shows the temperature distribution on the ink surface when a conventional heat transfer ink sheet is used and thermal energy is applied with a thermal head. 201 is a thermal head, the horizontal axis of the graph is the relative position with respect to the head, and the vertical axis is the relative humidity. The temperature distribution when changing the voltage value or pulse width of the voltage pulse applied to the thermal head is shown in I in the figure.
It increases in the order of l ■l m I■. As can be seen in the figure, the temperature distribution is very steep, and it is clear that the dot diameter is not easily modulated. In order to improve upon these drawbacks, Kosha et al. adopted a structure in which a metal layer is provided within the ink sheet in order to facilitate the conduction of heat from the thermal head in the surface direction of the ink sheet, that is, in the radial direction of the dots.

FIG. 3 shows a cross-sectional view of a heat transfer ink sheet according to the present invention. In the figure, 301 is a base layer, 302 is a metal layer, and 303 is an ink layer. The third factor α) is one in which there is a metal layer between the base layer and the ink layer, and Figure b) is one in which a metal layer is provided on the opposite side of the ink layer of the base layer. Since the metal layer has thermal conductivity that is one order of magnitude higher than that of plastic or wax, heat from the thermal head is easily transmitted in the surface direction of the sheet within a unit time. FIG. 2b) shows the measurement of the surface temperature distribution of the ink using the heat transfer ink sheet according to the present invention in the same manner as in the second factor α). When the thermal energy from the head is increased, the shift of the temperature distribution in the width direction (sheet concave direction) becomes larger than the second factor α). In other words, the dot diameter is easily modulated.

In manufacturing sheets, metals have the advantage of being easy to coat with a thin layer of V by vapor deposition, sputtering, or other methods.

As metals, A71Au, Ou, N1. Or.

It is not particularly limited as long as it can be coated on a film.

The thickness of the metal layer needs to be optimized depending on the base layer, the ink layer, the shape of the thermal head, etc. [Example] An example of the present invention will be described.

The structure of the heat transfer ink sheet is as shown in the third factor α). Using a PET film with a thickness of 4μμ as the base layer,
An aluminum layer with a thickness of 1 μm was provided on the surface by vapor deposition. Next, the aluminum layer was coated with the following ink materials using the Botto melt coating method, and the melting point of the ink was adjusted to 75°C.

Using a Kono ink sheet, solid transfer was performed to a thermal of 8 d0t/m rad. The reflected humidity was measured by changing the voltage pulse applied to the thermal head.

FIG. 4 is a comparison of the dark modulation of the conventional heat transfer ink sheet and the heat transfer ink sheet according to this embodiment. The horizontal axis of the figure shows the voltage pulse width, that is, the applied energy, and the vertical axis shows the reflected density. In the figure, B is the reflection density curve when the conventional heat transfer ink sheet is used, and A is the reflection density curve when the heat transfer ink sheet of this embodiment is used.

As can be seen from (2), in the case of the present invention, the slope of the density curve is small, and the density can be easily modulated.

〔effect〕

As described above, the heat transfer ink sheet according to the present invention
Since it has a structure that allows dot diameter modulation to be applied inexpensively, density modulation is applied smoothly to the applied energy, making it possible to achieve image output with high surface quality, which is farthest from half-toned display such as full-color hard copies.

[Brief explanation of drawings]

FIG. 1 shows a principle diagram of thermal transfer recording using a conventional heat transfer ink sheet. FIG. 2 (α), Cb) shows the temperature distribution between the ink light of the conventional thermal transfer ink sheet (α) and the ink light of the present invention. FIGS. 3(α) and 3(b) show cross-sectional 1MJ diagrams of the heat transfer ink sheet according to the present invention. Figure 4 shows the density modulation when the pulse width applied to the thermal head is changed. Applicant Suwa Seikosha Co., Ltd. Agent Patent Attorney Mogami Tsutomu Figure 1 Figure 2U (α) (Ra) Third Cabinet Figure 4

Claims (1)

[Claims] A thermal transfer ink sheet used in a thermal transfer printing device-1 that applies thermal energy to activate the thermoplastic ink and transfer it to a transfer medium to obtain characters/images, at least a thermoplastic ink layer; A thermal transfer ink sheet characterized by having a metal layer.