JPS60219091A - 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 resin compound layer containing a fine powder of a heat-conductive material. CONSTITUTION:The thermoplastic ink layer 303 and the resin compound layer (preferably having a thickness of 1-5mum) 302 containing a fine powder of a heat-conductive material (preferably, graphite, a metal or a mixture thereof) preferably in an amount of not less than 30wt% are provided on a base layer (e.g., a condenser paper, preferably, having a thickness of 3-15mum) 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 printing device that applies thermal energy to 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]

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 of the device, low cost, ease of maintenance, image clarity, and tamperability.

However, thermal transfer printers can basically only display dots in binary values (1 or 0), so in order to achieve full color gradation, methods such as the density pattern method and dither method are required. A method is adopted in which one pixel is represented by a plurality of dots using the 1JII product gradation method. However, in this method, as the number of gradations increases, the 1. This has the disadvantage that the IJJ product increases and the resolution decreases.

〔the purpose〕

The present invention improves the above-mentioned drawbacks, and by improving the ink sheet, the size of the pixel diameter can be changed according to the magnitude of the recording energy, that is, it is possible to perform hj product modulation of both methods, and it is possible to achieve high quality. The purpose of the present invention is to provide an ink sheet that can output a full-color hard copy.

〔overview〕

That is, the present invention applies thermal energy to activate thermoplastic ink and transfer it to a transfer medium, thereby forming characters and
The present invention provides a thermal transfer ink sheet used in a thermal transfer type printing device for obtaining images, which is characterized by having at least a thermal transfer ink layer and a resin compound layer containing thermally conductive fine powder. .

Furthermore, the present invention provides a thermal transfer ink sheet in which the thermally conductive fine powder described above is a gold layer, graphite, or a mixture thereof.

Explain details.

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 PET or condenser paper, 106 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 due to heat conduction, a portion of the ink layer (106) is melted and transferred to the transfer medium (107).

With conventional methods, it is extremely difficult to modulate the dot diameter with good reproducibility.

FIG. 2 (α) 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 mIK. The temperature distribution when changing the voltage value of the voltage pulse applied to the thermal head or the pulse 1j increases in the order of I, II, m, and N in the figure. As can be seen in the figure, the temperature distribution is very steep, and the modulation of the dot diameter is difficult to understand. In order to improve this drawback, Fuene et al. used a thermally conductive fine powder inside the ink sheet so that the heat from the thermal head was transmitted in the ink sheet surface direction, that is, in the dot radial direction. An f# structure was adopted, which has a resin condensed land layer containing .

FIG. 3 shows a sectional view of a heat transfer ink sheet according to the present invention. In the figure, 601 is a base layer, 302 is a resin concrete land layer containing thermally conductive fine powder, and 303 is an ink layer. Figure 3 (α) shows a layer containing thermally conductive fine powder between the base layer and the ink layer.
In the same figure (b), the compound layer is provided on the ink layer of the base layer and the reflector. Since the H4 JK compound containing fine powder of graphite and gold layer has a higher thermal conductivity than the base layer and the ink layer, the heat from the thermal head is easily transmitted in the surface direction of the sheet within a unit time. Figure 2 (
b) uses the heat transfer ink sheet according to the present invention, and the second [
Similarly to 2 [α), the hexagonal vortex distribution of the ink was measured. When the thermal energy from the head is increased, the temperature distribution shifts in the horizontal axis direction (the sheet circumferential direction) due to the second factor (α
It is thicker than the original. In other words, the dot diameter is easily modulated.

The resin compound layer containing Kurofune or gold layer fine powder is
It is formed by drying after coating using a solvent method or the like. The ratio of the fine powder to the resin is preferably 30 wt % or more in order to improve the thermal conductivity of the compound. The thickness of the base layer is preferably 3 to 15 .mu.fi, and the thickness of the resin compound layer is preferably 1 to 5 .mu.fi.

〔Example〕

Examples of the present invention will be described.

The structure of the heat transfer ink sheet is shown in FIG. 3(a). A PET film with a thickness of 6 μm was used as the base layer, and polyvinyl butyral resin containing 40 wt% of graphite was used as the base layer.
The toluene-ethanol graphite/metal fine powder is uniformly deposited on the paste using methods such as electrostatic powder coating or scattering adsorption. It is necessary that the individual particles are in contact with each other.The thickness of the base layer is preferably 6 to 15 microns, and the thickness of the il powder layer is preferably 1 to 5 microns.

〔Example〕

Examples of the present invention will be described.

The structure of the heat transfer ink sheet is shown in Figure 6 (α). A PET film with a thickness of 9 μm was used as the base layer, and graphite powder was uniformly sprinkled on the surface to a thickness of 2 μm. Next, a fine powder layer was formed. Tsukuda uses the hot melt coating method to create the lower dU2.
All ink materials coated Ink material composition Oxidized wax 2 Dwt% EVA 10 /F Paraffin wax 60 Carbon black 10 The melting point of the ink was adjusted to 80°C.

Using this ink sheet, put it in a Nosu (1:i) solution with a resolution of 8 //, stir thoroughly to dissolve it, coat it on the film 7, and dry it to form a 2μ sacrificial film. Ta. Next, the following ink material was coated using a hot melt coating method.

Ink material composition Carnauba wax 30wt% EVA 5tt Parafine wax 55 Carbon black 10 An ink sheet with a melting point of 85° was used to perform solid transfer using a multi-head with a resolution of 8d0t/min. The curve in FIG. 4A shows the results of measuring the reflection performance of the printed sample by changing the voltage pulse. Figure B shows a conventional heat transfer ink sheet (
This is a case where a base layer and an ink layer are used. As can be seen from the figure, in the case of the present invention, the slope of the density curve is small and constant, and it is easy to apply manufacturing modulation.

〔effect〕

As described above, the heat transfer ink sheet according to the present invention is
Since it has a structure that allows dot diameter modulation to be applied inexpensively, the manufacturing modulation is applied smoothly to the applied energy, making it ideal for halftone display such as full-color hard copies, and achieving high-quality image output.

[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 of the ink surface of the thermal transfer ink sheet (α) of the conventional method and b) of the present invention). FIG. 3(α)+(b) shows a cross-sectional view of a heat transfer ink sheet according to the present invention. FIG. 4 shows the density modulation when changing the pulse width applied to the thermal head. Applicant Suwa Seikosha Co., Ltd. Agent Patent Attorney Tsutomu Mogami 1 L Tomi) Figure 2

Claims (1)

[Claims] (Re) In 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 two images of characters,
Thermal transfer ink sheet (2) characterized by having at least a thermoplastic ink layer and a compound layer containing thermally conductive fine powder.The thermally conductive fine powder is graphite, metal, or a mixture thereof. A thermal transfer ink sheet as set forth in claim 1, characterized in that: