JPS61123588A - Heat transfer recording sheet - Google Patents

Abstract

PURPOSE:To obtain subject sheet with which continuous tone recording with pigment is feasible, and a density may be continuously controllable in accordance with temperature rise recording control, and which is useful for a full color printer etc. of office automation etc. by providing a special heat transfer layer on one side of a sheet shaped substrate. CONSTITUTION:(A) A saturated aliphatic hydrocarbon resin which is contained as a binder material, and (B) at least either one of a pigment or a dye which is contained as a coloring agent in an ink material and (C) auxiliary ink transfer particles 4 of a diameter which is larger than the thickness of the layer of the ink material are mixed in the ink material to form a heat transfer layer 2, and this layer is provided on both edges of one side of a sheet substrate 1 and, thus, subject sheet is obtained. Additionally, it is further desirable to add solid paraffin to the constituent (B).

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is useful for thermal transfer recording of monochromatic gradation images, color images, etc. on a recording medium in continuous gradation using a thermal recording head, a laser beam, etc. The present invention relates to a thermal transfer recording sheet.

BACKGROUND OF THE INVENTION Conventional thermal transfer recording sheets include a sheet-like heat-resistant substrate such as a polyethylene terephthalate (PE'T) film or capacitor paper with a thickness of approximately 7 μm, and 20% by weight of carnauba wax and ester as binder materials. A hot melt material consisting of 40% by weight of wax, 10% by weight of mineral oil, and 10% by weight of other auxiliary agents is used, and a thickness of an ink material layer is obtained by mixing 20% by weight of a pigment coloring material with this hot melt binder material. A thermal transfer recording sheet in which a thermal transfer layer of about 3 μm is formed by a hot melt coating method and whose melt transfer temperature is about 60'C is known (for example, Y, Tokunaga and K, Sugiyam).
a.

”Thermal Ink-Transfer Image
ing', IEEET Trans, on Elect
Ron Devices, vol, ED-27.

PP, 21a-222, 1980. ).

Thermal transfer using this type of thermal transfer recording sheet is generally carried out by pressing a known thermal recording head against the back surface of the base sheet with a recording medium such as recording paper in pressure contact with the thermal transfer recording sheet, and transferring the thermal transfer layer to the base sheet. The ink material is selectively heated and recorded by the thermal recording head through the recording medium, thereby melting and transferring the ink material to the recording medium.

Problems to be Solved by the Invention In such conventional thermal transfer recording sheets, the ink material layer extends from the substrate sheet side to the surface of the ink material layer, and the ink material does not adhere to the recording medium until the binder material has completely melted. , transcribed. In this case, since the ink material melted in the thickness direction of the ink material layer is attached and transferred to the recording medium at once, it is useful for binary density recording such as characters and figures, but it is useful for recording images with halftones, etc. Digital gradation methods, such as dithering and density pattern methods, are being considered for use in applications requiring continuous gradation.

However, with this type of digital gradation method, not only is the equipment expensive as it requires complex recording signal processing, but high image quality can be expected, and in addition, the total resolution is higher than the recording density of the thermal recording head. It was inevitable that there would also be a significant decline.

The present invention has been made in view of the above points, and an object of the present invention is to provide a thermal transfer recording sheet that can continuously control the transfer recording density in response to temperature increase recording control.〇To solve the problems. In order to solve the above problems, the present invention provides a thermal transfer recording sheet containing an alicyclic saturated hydrocarbon resin as a binder material,
A thermal transfer method in which an ink material containing this binder material, a coloring agent constituted by at least one of a pigment or a dye, and ink transfer auxiliary particles having a particle size equal to or larger than the thickness of a layer made of this ink material are mixed into the ink material. A layer is arranged and configured on one side of a sheet-like substrate.

Further, solid paraffin is further added to the binder material, and a thermal transfer layer is arranged on one surface of the sheet-like substrate in the same manner as described above.

Function In the present invention, thermal transfer recording is performed by contacting and pressing the recording medium and the thermal transfer layer side as in the conventional method, and controlling the temperature increase from the sheet-like base side of the thermal transfer recording sheet using a thermal recording head or the like. Due to this temperature increase control, the viscosity of the alicyclic saturated hydrocarbon resin contained as a binder material in the thermal transfer layer changes continuously, and the ink transfer auxiliary particles whose particle size is greater than the thickness of the ink material layer As a result, complete contact with the recording medium can be avoided, so that through the contact point between the recording medium and the ink material layer or the ink auxiliary particles, the binder material soaks into the recording medium in proportion to the viscosity of the ink material, and the recording medium Expansion in the surface direction is obtained. At this time, the coloring material is also transferred in proportion to the amount of the binder material transferred, and direct continuous gradation recording can be performed by controlling the temperature increase using a thermal recording head or the like.

Here, the temperature increase control is performed in a thermal recording head, etc.
The input signal can be pulse width modulated (PWM) or amplitude modulated (
AM) and do 1.

Embodiment Figures show cross-sectional structural diagrams of one embodiment of the thermal transfer recording sheet of the present invention.

The thermal transfer recording sheet is one in which a thermal transfer layer 2 is arranged on one side of a sheet-like substrate 1. The thermal transfer layer 2 contains an alicyclic saturated hydrocarbon resin as a binder material, and a layer 3 of an ink material containing this ink material and a coloring agent composed of at least one of a pigment or a dye is coated with a layer 3 having a thickness greater than this thickness. It is constructed by mixing ink transfer auxiliary particles 4 having a particle size.

The thermal transfer layer 2 is formed by dissolving and dispersing an ink material in a solvent containing at least one good solvent for an alicyclic saturated hydrocarbon resin constituting the binder material, applying the solution to the sheet-like substrate 1, and evaporating the solvent. It is obtained by a solvent coating method or a true melt coating method. At this time, according to the solvent coating method, pinholes 5 are formed when the solvent evaporates.

For example, the sheet-like substrate 1 has a thickness of 3.5 μm to 1 μm.
Polyethylene terephthalate with a diameter of about 6 μm.

Resin films such as polyimide, cellulose 7A/, polycarbonate, triacetylcellulose, and nylon, or heat-resistant papers such as high-quality paper, glassine paper, tracing paper, and capacitor paper can be used.

As the alicyclic saturated hydrocarbon resin contained in the binder material, there is Arco/ manufactured by Arakawa Chemical Industry Co., Ltd., which has a softening point (ring and ball method) of 70'C to 126C.

As the colorant, organic or inorganic pigments and dyes used in ordinary printing inks, paints, etc., or mixtures thereof can be appropriately selected and used.

The ink transfer auxiliary particles 4 can have a certain particle size distribution, and include powder particles of high melting point resin, such as polycarbonate, polystyrene, polypropylene, nylon, cellulose, mari, titanium oxide, silicon oxide 9 quartz powder,
Powder particles of inorganic materials such as aluminum oxide are used. If the average particle diameter is less than 1.5 μm, the thickness of the layer 3 of the ink material will be too small, making it difficult to obtain a large maximum density during transfer recording. On the other hand, if the average particle size exceeds 16 μm, the heat capacity of the ink transfer auxiliary particles 4 becomes excessively large, and the ink material layer 3 is
The amount of heat applied to the transfer layer decreases, and the transfer efficiency decreases.

Therefore, the preferred average particle size of the ink transfer auxiliary particles 4 is 1
．． It is 5 μm to 16 μm. Furthermore, the average particle size is 2μ
≠ Improved performance and recording sensitivity.

Further, the ink transfer auxiliary particles 4 are arranged so that at least one particle whose particle size is larger than the thickness of the ink material layer 3 is present for each recording pixel, and the maximum is the most dense particle. If it is placed, you can select as appropriate between them. Furthermore, it is possible to have a certain particle size distribution within the ink transfer auxiliary particles 4 with a particle size larger than the thickness of the layer 3 of ink material.

When the ink material uses, for example, a dye as a colorant,
If the weight percentage of the ink material in layer 3 is less than 2%, the transfer recording density will be insufficient. On the other hand, if pigment is used as a colorant, if it exceeds 60%, the binder material (alicyclic saturated hydrocarbon resin) Since the pigment cannot be sufficiently restrained and the adhesive strength with the recording paper becomes weak, the transferred ink material tends to peel off. Therefore, the weight percentage of the colorant is appropriately selected in the range of 2% to 60%, and therefore the binder material (alicyclic saturated hydrocarbon resin) is selected in the range of 98% to 40% accordingly. .

In particular, ink materials containing 10% to 60% of the colorant and 90% to 60% of the binder material (alicyclic saturated hydrocarbon resin) have excellent transfer recording density and continuous gradation, and are recommended. This is the range. This range is particularly effective when using pigments as colorants.

Benzene is a good solvent for the alicyclic saturated hydrocarbon resin used in the solvent coating method.

It can be selected from aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as chloroform and carbon tetrachloride, and η-octyl alcohol.

The thermal transfer layer 2 has a weight range of 10 cm to 75 cm, and therefore the ink material 9
If it is selected from 0% to 26%, continuous gradation properties and recording sensitivity can be particularly improved. Moreover, the coating amount of this layer is O, B! /rr?
If it is less than 5y/m, the maximum density of the transfer recording will be low, and if it exceeds 5y/silence, the layer will become too thick and extra heat will be required to reduce the viscosity of the binder material, resulting in a significant decrease in recording sensitivity. Therefore, the coating amount is 0.8-6y/rrl
choose.

As the recording medium, paper such as high-quality paper, coated paper, art paper 1 synthetic paper, and plastic films such as polyethylene terephthalate, polypropylene, and cellophane can be used.

Another example will be shown. The configuration is the same as in FIG.

By using solid paraffin in addition to the alicyclic saturated hydrocarbon resin as a binder material, it is possible to transfer the low concentration region more smoothly.

The solid paraffin used has a melting point of 44°C to 69°C.

As a binder material, the weight percentage of solid paraffin is 60%.
Above is the physical strength of the ink material itself.

Binding force of colorants (especially pigments) and adhesion to recording media.

Due to poor fixing properties, stable recorded matter cannot be obtained.

Therefore, the binder material is composed of 50% or less of solid paraffin and 50% or more of alicyclic saturated hydrocarbon resin.

As described above, in the composition of the ink material, auxiliary agents such as pigment dispersants and surfactants can be mixed as necessary, and other resins, waxes, etc. can be mixed as appropriate with respect to the binder material.

Furthermore, the method of forming thermal transfer is not subject to the above-mentioned restrictions.

Furthermore, 1. Thermal transfer recording can be achieved by controlling the temperature rise from the base sheet side while the recording medium and the thermal transfer layer 2 side are pressed in contact with each other, and then separating the recording medium and the thermal transfer recording sheet. This temperature increase control is obtained by pulse width modulation or pulse width modulation of an input signal applied to a thermal recording head, a laser beam emitter, or the like.

Effects of the Invention As described above, the present invention has the advantage that the binder material (alicyclic saturated hydrocarbon resin, solid paraffin) whose viscosity has been reduced by temperature-raising recording control is applied to the area where the recording medium is in direct contact with the ink material layer or the ink layer. to the recording medium via transfer auxiliary particles,
Since the colorant is also transferred in proportion to the amount of the transferred binder material, it is possible to perform continuous gradation recording using pigments, which was difficult with conventional melt transfer recording methods. Moreover, as a full-color printer, its industrial effects are extremely impressive.

[Brief explanation of the drawing]

The figure is a cross-sectional structural diagram of a thermal transfer recording sheet in one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Sheet-like substrate, 2... Thermal transfer layer, 3... Layer of i/rematerial, 4... Ink transfer auxiliary particles. Name of agent: Patent attorney Toshio Nakao and one other person Procedural amendment (Blade side, April 25, 1985)

Claims (2)

[Claims] (1) An ink material containing an alicyclic saturated hydrocarbon resin as a binder material and a coloring agent composed of this binder material and at least one of a pigment and a dye, and a particle size that is equal to or greater than the thickness of the layer made of this ink material. 1. A thermal transfer recording sheet, comprising: a thermal transfer layer in which the ink material is mixed with ink transfer auxiliary particles comprising: a thermal transfer layer on one side of a sheet-like substrate; (2) The thermal transfer recording sheet according to claim 1, wherein the binder material further contains solid paraffin.