JPH0333516B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field, etc.] The present invention relates to a thermal transfer recording medium capable of forming a dye image by thermally transferring a sublimable dye. More specifically, it is a thermal transfer recording medium that can produce a dye image with high sharpness and multi-gradation properties that is stable against heat, light, etc. on a recording sheet such as plain paper through a thermal transfer process using a sublimable dye. Regarding. [Prior Art] Conventionally, methods have been known in which thermal paper is colored and images are recorded using a thermal head composed of thick-film resistors, thin-film resistors, semiconductor resistors, etc., or a heat source such as a laser or a xenon lamp. Since these methods use thermal paper, there are problems with the stability of the image against heat and light, and there are also disadvantages of high manufacturing costs.Furthermore, for colorization, it is necessary to have multiple coloring layers, so it is necessary to use only two colors. The disadvantage was that there was a limit. As a thermal recording method that solves the above-mentioned drawbacks, for example, a coloring material that is solid or semi-solid at room temperature is coated on a support such as paper or resin film, as described in Japanese Patent Application Laid-open No. 15446/1983. The coloring material on the support is brought into contact with the recording sheet, and the coloring material on the support is heated and selectively transferred to the recording sheet using a heat source controlled according to image information. A thermal transfer method for recording is known. The thermal transfer process in this method uses a coloring material mixed with a dye in a solvent with a low melting point and small heat capacity, and a melt transfer type that thermally transfers the dye together with the solvent, and a melt transfer type that uses a sublimable dye as the coloring material and uses a dye alone. A sublimation transfer type that performs sublimation transfer was known. Among these, the melt transfer type has the disadvantage that if a certain amount of thermal energy or more is applied, all the coloring material is transferred, making it difficult to obtain gradation of the image. On the other hand, the sublimation transfer type is a desirable method in order to obtain gradation because the dye is transferred depending on the amount of thermal energy applied. However, since the sublimation transfer type uses sublimable dyes for image formation, there are problems with image fixability and storage stability due to re-sublimation of the dyes, especially when transferring to plain paper.
It had the disadvantage that the color density was low and the color density decreased significantly due to re-sublimation of the dye over time. Therefore, in order to obtain multi-gradation image recording, there is a strong desire to develop a thermal transfer recording medium that uses an advantageous sublimable dye and can form stable images on plain paper. [Object of the Invention] The present invention was made in view of the above circumstances, and its purpose is to provide a film with good sharpness and high color density.
An object of the present invention is to provide a thermal transfer recording medium for obtaining a dye image having multiple gradations and good storage stability on a recording sheet such as plain paper. [Structure of the Invention] Hereinafter, the thermal transfer recording medium and thermal transfer recording method of the present invention will be explained based on the accompanying drawings. FIG. 1 is a schematic sectional view showing an example of the thermal transfer recording medium of the present invention, and FIGS. 2 and 3 are schematic explanatory views showing a thermal transfer recording method using the thermal transfer recording medium of the present invention. In FIG. 1, 1 is a support, on which a layer 2 containing a dye that can be transferred by sublimation, and further thereon a layer 3 containing an organic dye-trapping compound and a heat-melting compound. It is provided in an integral layer. Sublimation transfer in the present invention (in the present invention,
A dye that melts upon sublimation or vaporizes after being dissolved is also included in the sublimation transferable dye in the present invention. )
The sublimation-transferable dye in the layer 2 containing dyes is combined with an organic dye-trapping compound and an organic dye-trapping compound in response to thermal energy provided by the heating head 6 of the thermal printer, as shown in FIGS. It moves to the layer 3 containing the heat-fusible compound, where it acts on the organic dye-trapping compound to reduce or eliminate its sublimability. Layer 3 containing a thermofusible compound
is in a molten state at this time, and is melt-transferred onto the recording sheet 4 disposed in contact with the layer 3 containing the heat-melting compound, accompanied by the sublimable dye whose sublimability has decreased or disappeared. As a result, a printed image 5 made of the dye is formed. In the present invention, the sublimation-transferable dye is very efficiently transferred to the layer 3 containing the heat-melting compound according to the thermal energy, so it is possible to obtain a multi-gradation and high-density printed image. can. Moreover,
Sublimation-transferable dyes interact with organic dye-trapping compounds to essentially become non-sublimable dyes, so that printed images that are highly stable to heat can be obtained. Furthermore, in the case of conventional heat-melting transfer type thermal transfer recording media, there was a drawback that the area of the transferred image changes due to changes in thermal energy, but in the present invention, the area of the transferred image changes due to changes in thermal energy. The area where the non-sublimable dye exists in the layer is determined by the area where the dye that sublimates and transfers depending on the heat energy exists, so it is almost constant in any gradation part of a multi-gradation printed image. It has a colored area of That is, there is very little difference in resolution between each gradation. In the present invention, it is preferable that the melting temperature of the layer 3 containing the heat-melting compound is designed to be equal to or lower than the temperature at which the dye capable of sublimation transfer sublimates. As the organic dye-trapping compound used in the present invention, the compounds shown in [A], [B], and [C] below are preferable. [A] Compound represented by the following general formula General formula [] X-(Y-Z)n or Y-(Z)l or X-[Y-(
Z)l]n In the above formula, ~13 substituted or unsubstituted arylene groups, arylene alkylene groups having 6 to 20 carbon atoms,

[Formula] Group or

[Formula] is a group (where R ¹ is a hydrogen atom, the number of carbon atoms is 1 to
6 substituted or unsubstituted alkyl groups or substituted or unsubstituted aryl groups having 6 to 13 carbon atoms. ), Y is an electron-withdrawing group, e.g. -
SO ₂ −, −CO−, −SO−, −O−, −S−, −
COO−, −NR ² −,

【formula】

【formula】

【formula】

【formula】

[Formula] (where R ² represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and m is 1
Or represents 2. ), Z is a residue selected from the following groups; -CH=CHR ¹

【formula】

【formula】

[Formula] -CH ₂ W -CH ₂ CH ₂ W -CH ₂ CH ₂ OSO ₂ H (However, W represents a halogen or arylsulfonyloxy group.) n is a positive integer from 1 to 4 (n is When 2 or more, -(Y-Z) may be different from each other.)l is a positive integer of 1 to 3. [B] Compound represented by the following general formula [] General formula []

[Formula] or

[Formula] However, Q ¹ and Q ² are -Cl-,

〔Example〕

Preferred examples of the thermal transfer recording medium of the present invention are shown below, but the present invention is not limited to these examples. Example 1 First, a composition having the following composition (A) was applied onto a polyester film having a thickness of 6μ so that the thickness after drying was 3μ, and after drying, a composition having the following composition (B) was applied on top of it. The material was coated in multiple layers so that the thickness after drying was 1 μm and dried to obtain a thermal transfer recording medium (a) of the present invention. Composition (A) Composition Parts by weight

[Formula] 1.5 Diacetyl cellulose 3.0 Acetone 95.5 Composition (B) Composition Part by weight Compound [A]-(3) 0.5 Permarin PN (Aqueous wax emulsion manufactured by Sanyo Chemical Industries) 50.0 Surfactant 0.03 Water 49.47 Obtained Printing was performed on plain paper using a thermal printer using the thermal transfer recording medium (a). that time,
When printing was performed by varying the application time of the heavy pressure applied to the heating head (the applied voltage was constant), a yellow recorded image with good gradation was obtained as shown in FIG. Note that the resolution of the obtained recorded images was good with almost no difference in each gradation. Example 2 In the same manner as in Example 1, compositions having the following compositions (C) and (D) were coated in a multilayer manner to obtain a thermal transfer recording medium (b) of the present invention. Composition (C) Composition Parts by weight

[Formula] 2.0 Diacetyl cellulose 3.0 Acetone 95.0 Composition (D) Composition Parts by weight Compound [B] - (1) 1.0 Permaline PN 50.0 Surfactant 0.03 Water 48.97 Using the obtained thermal transfer recording medium (B), When printed on plain paper using a thermal printer in the same manner as in Example 1, a magenta recorded image with good gradation was obtained. There was almost no difference in resolution of the obtained recorded images at each gradation level. Example 3 In the same manner as in Example 1, compositions having the following compositions (E) and (F) were coated in a multilayer manner to obtain a thermal transfer recording medium (c) of the present invention. Composition (E) Composition Parts by weight

〔Effect of the invention〕

As is clear from the above examples, according to the present invention, a dye image with good sharpness, high color density, multiple gradations, and good storage stability can be obtained on plain paper.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of the thermal transfer recording medium of the present invention, FIGS. 2 and 3 are schematic explanatory views showing a thermal transfer recording method using the thermal transfer recording medium of the present invention, and FIG. The figure is a graph showing the relationship between the application time and the density of a recorded image when the recording medium (a) of the present invention is used.

Claims (1)

[Claims] 1. On a support, a layer containing a dye that is solid at room temperature, can be sublimated transferred by heating, and has at least one of a hydroxyl group, an amino group, and a substituted amino group; A layer containing an organic dye scavenging compound and a thermofusible compound having a group capable of reacting with the group of the dye and capable of reacting with the dye to reduce or eliminate the sublimability of the dye is provided. Features of thermal transfer recording media.