JPH0739207B2 - Transfer-type thermal recording method - Google Patents

Description

The present invention relates to a recording method for forming characters or images on an image receptor by heat, and is used for video printers, facsimiles, copiers, and color / hard copies that are easy to maintain and operate. Is what you can get.

Conventionally, inkjet methods, electrophotographic methods, etc. have been proposed and partially put into practical use as methods for obtaining color / hard copies, but the maintenance and operation methods of the device are complicated,
There is a problem that the price is also high.

Therefore, in recent years, it is particularly used for video printers and the like, and using an ink sheet in which color ink is solidified, the ink is melted by a heat source such as a laser or a thermal head controlled by an electric signal and transferred to an image receiver. There is proposed a so-called transfer type thermal recording system in which an image is formed by transferring a color material by sublimation, vaporization or the like. However, the heat-melt transfer method uses an ink sheet in which a color material is held by a low-melting wax, and transfers the color material to the image receiver side together with the wax melted by heating, and a good hue cannot be obtained by the transferred wax. However, since halftone cannot be obtained, there is a problem that the image quality is inferior.

In addition, the sublimation / vaporization transfer method is an application of the sublimation transfer printing technology that has been used for printing synthetic fibers in the past, and uses an ink sheet that holds a disperse dye that is relatively easy to sublime or vaporize as a coloring material with a binder. It is used to transfer only the dye to the image receptor side by sublimation or vaporization transfer (also partially melt transfer) by heating, and intermediate gradation is easily obtained, but there are the following problems.

(1) The image receiving layer applicable to the disperse dye is limited to polyester resin or acetate resin.

(2) Since the image receiving layer is a polymer having a relatively low melting point, the color material holding layer and the image receiving layer are fused during transfer.

(3) It requires long time or high temperature heating to transfer the dye.

(4) The transferred dye is only dispersed in the image-receiving layer, sufficient color development cannot be obtained, and the fastness is poor.

(5) Since the dye itself is sublimable, the storage stability of the sheet before transfer or the color image after transfer is poor.

The present invention is intended to solve the problems in the various recording methods as described above, and provides a thermal recording method capable of obtaining a color image having sufficient colorability and good fastness with good intermediate gradation. is there.

That is, the present invention contains a compound having active methyl or active methylene which is transferred to an image receptor by sublimation or vaporization by heating and chemically reacts with an aldehyde compound or a nitroso compound contained in the image receptor to form a dye. Selective transfer of a transfer agent to a receptor containing an aldehyde compound and / or a nitroso compound (partial)
It is a transfer type heat-sensitive recording method characterized by forming an image on an image receptor by heating the image to an image receiver.

In the present invention, the image receptor is manufactured as follows, for example. An aldehyde compound or a nitroso compound is dissolved or dispersed in a suitable organic solvent together with a synthetic resin such as polyester resin or polyamide resin, coated on paper using a bar coater, knife coater, roll coater or the like, and dried to obtain an image receptor. .

On the other hand, the transfer body is manufactured, for example, as follows. A compound having active methyl or active methylene is dissolved or dispersed in a suitable organic solvent together with a binder, and a bar coater,
A knife coater, a roll coater or the like is used to coat the support and dry it to obtain a transfer body. As the binder, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, cellulose acetate, sodium alginate, polyvinyl alcohol, polyvinyl acetate, polycarbonate resin, polyester resin, polyamide resin,
Phenolic resins, polyvinyl chloride, vinyl acetate, polyvinylidene chloride, starch, gum arabic, gelatin and the like are used.

As the organic solvent, alcohols, aromatic hydrocarbons,
Hydrocarbons, ethers, esters or mixed solvents thereof are used.

As the substrate of the transfer body, condenser paper having a thickness of 5 to 20 μm, electrolytic condenser paper, polymer films such as polyester polyamide, polyether sulfone, etc. are used.

In the present invention, the color is developed by heating, the compound having active methyl or active methylene contained in the transfer body is transferred to the image receptor by sublimation or vaporization, and undergoes a chemical reaction with the aldehyde compound or the nitroso compound contained in the image receptor. It is believed that this is done by forming a dye. The hue can be freely selected from yellow to green by a combination of an aldehyde compound or a nitroso compound and a compound having active methyl or active methylene.

In the present invention, the presence of an organic base in the image receptor at the time of color development is advantageous because the color development rate at the time of heating is accelerated.
As the organic base having such a purpose, various organic compounds having a proton accepting ability can be used, and amines, guanidine derivatives, nitrogen-containing heterocyclic compounds and the like are effective.

In the present invention, since the compound that is sublimated or vaporized by heating has a relatively low molecular weight, the thermal energy required for transfer can be small, the transfer speed is fast, and high-speed recording can be supported.

On the other hand, since a dye is formed by a chemical reaction on the image receptor to develop a color, it has features such as a clear hue, high density, and excellent fastness.

According to the present invention, by selecting a compound having active methyl or active methylene, yellow, magenta, and cyan dyes are produced for the same aldehyde compound or nitroso compound, so select an appropriate combination. Thus, a full-color image can be obtained. For example, three types of compounds having active methyl or active methylene that form an image receptor with a specific aldehyde compound or nitroso compound, and chemically react with the compound to produce yellow, magenta, and cyan dyes, respectively. A full-color image can be obtained by forming the transfer member of (1) and superimposing the images of yellow, magenta, and cyan on the image receiving member in a frame-sequential manner according to the pixel property information.

As the aldehyde compound in the present invention, specifically,
The following compounds may be mentioned.

Benzaldehydes, naphthalene aldehydes, indole aldehydes, tribase aldehydes, tetrahydroquinoline aldehydes, quinoline aldehydes, thiazole aldehydes bendthiophene.

Specific examples of the nitroso compound include the following compounds.

Nitrosoanilines, nitrosotetrahydroquinolines, nitrosoquinolines, nitrosonaphthylamines,
Nitrosophenols, nitrosonaphthols, nitrosoindoles, nitrosothiazoles, nitrosothiophenes, nitrosopyridones, nitrosopyridines.

Examples of the compound having active methyl or active methylene in the present invention include the following. Malonnitrile, cyanoacetic acid esters, cyanoacetic acid amides,
Thiazol-2-yl-cyanoacetic acid esters, thiazol-2-yl-malondinitriles.

Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, "part" means "part by weight".

Example 1 An ink consisting of 6 parts of 4-dimethylaminobenzaldehyde, 6 parts of ethyl cellulose and 88 parts of isopropyl alcohol was applied to a 12 μm thick condenser paper using a bar coater and dried to obtain a transfer body.

On the other hand, a crude forming liquid consisting of 5 parts of malon nitrile, 20 parts of polyester resin and 75 parts of methyl ethyl ketone was applied to coated paper using a bar coater and dried to obtain an image receptor.

Then the heating apparatus heat Inclined iron tester (manufactured by Yasuda Seiki Co.), 120 ° C. at a weight ^{30g / cm 2, 130 ℃,} 140 ℃, 150 ℃, 1
It was heated at 60 ° C and 170 ° C for 10 seconds. A clear yellow color was obtained on the side of the image receptor. As for the coloring density, a sufficient gradation was obtained in proportion to the heating temperature.

Examples 2 to 62 In the same manner as in Example 1, except that the aldehyde compound is replaced with the aldehyde compound or the nitroso compound shown in Table-1, and the active methylene compound is replaced with the active methyl or methylene compound shown in Table-1, the image receptor and the transfer are obtained in the same manner. Create the body,
By heating them facing each other, similarly excellent color tone was obtained. The results are shown in Table-1.

Claims (1)

[Claims] 1. A compound containing active methyl or active methylene which transfers to an image receptor by sublimation or vaporization by heating and chemically reacts with an aldehyde compound or a nitroso compound contained in the image receptor to form a dye. A transfer-type heat-sensitive recording method, characterized in that a transfer body is selectively heated in a state of facing an image receptor containing an aldehyde compound and / or a nitroso compound to form an image on the image receptor.