JPH05155143A - Infrared heating type thermal transfer recording sheet - Google Patents

Abstract

(57) [Summary] [Purpose] In thermal transfer recording using infrared rays such as an infrared semiconductor laser as a heating means, by using a specific infrared absorber as a photothermal conversion material, good transfer sensitivity can be obtained.
Provided is a heat-sensitive transfer recording sheet capable of giving a high quality recorded matter. [Structure] A base film has a layer containing a heat transferable dye and an infrared absorbing substance, and the infrared absorbing substance has the following general formula (I): (In the formula, R represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and n is 0, 1 or 2.) An infrared heating type thermal transfer recording sheet which is a squarylium compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive transfer recording sheet used for heat-sensitive transfer recording, particularly dye transfer type heat-sensitive transfer recording.

[0002]

2. Description of the Related Art A dye-transfer type heat-sensitive transfer recording is a heat-sensitive transfer sheet in which a heat-sensitive transfer sheet having a coloring material layer containing a heat transferable dye on a base film and an image-receiving sheet having a dye-receiving layer on the surface are superposed. Is a recording method in which the dye in the heat-sensitive transfer sheet is transferred to the image-receiving sheet by heating to record. This recording method is applied to full-color image recording such as a video printer because the transfer amount of the dye can be controlled by the amount of heating energy and gradation can be expressed.

Conventionally, as a heating means for the transfer sheet, a line type thermal head in which a heating resistor element which generates heat in response to an electric signal is formed in a line on a substrate is used. However, it is difficult to uniformly form a large number of heating resistor elements on the substrate, which makes it difficult to manufacture a large thermal head, and it is difficult to record an image on a large screen. Further, since the formation density of the heating resistor elements is limited to about 6 to 12 per 1 mm, there is a problem in image recording requiring high resolution.

In order to solve the problems of these thermal heads, it has been proposed to use laser light as a heating means. As the laser light, a semiconductor laser that is small and obtains high energy is particularly advantageous. Currently, there are semiconductor lasers having a transmission wavelength of 650 to 850 nm in the red to near infrared region, but those in the near infrared region of 750 to 850 nm are mainly used. In order to heat the transfer sheet by using these semiconductor lasers as a heating means, it is necessary to include a photothermal conversion substance that absorbs laser light and converts the absorbed light into heat energy in the transfer sheet. The photothermal conversion substance used here is very important because it directly affects the recording sensitivity of the transfer sheet and also affects the quality of the recorded image. The photothermal conversion substance is required to have the following characteristics.

Good absorption efficiency of laser light Good conversion efficiency of absorbed light into heat Good solubility or dispersibility in solvent or water, good stability of coating liquid, film Easy to coat ・ Stable when the transfer sheet is stored, and does not adversely affect the dyes used together ・ No heat transfer, or very small compared to dyes As the conversion substance, for example, JP-A-63-
319191, JP-A-58-16888, JP-A-2-2
074 and many others have been proposed. However, these products do not always satisfy all the above-mentioned characteristics, and more excellent products are demanded.

[0006]

DISCLOSURE OF THE INVENTION The present invention uses an infrared absorbent having a specific structure as a photothermal conversion substance having excellent characteristics in thermal transfer recording using infrared rays such as an infrared semiconductor laser as a heating means. In other words, it is an object of the present invention to provide a heat-sensitive transfer recording sheet having good transfer sensitivity and capable of providing a high quality recorded matter.

[0007]

The heat-sensitive transfer recording sheet of the present invention has a layer containing a heat transferable dye and an infrared absorbing substance on a base film, and the infrared absorbing substance is represented by the following general formula (I).

[0008]

[Chemical 2]

(In the formula, R represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and n is 0, 1 or 2
Represents ) Is a squarylium compound represented by. The details of the present invention will be described below.

First, the infrared absorbent represented by the general formula (I) will be described. Specific examples of the squarylium compound represented by the general formula (I) include those shown in Table 1. These substances are known substances and are described in JP-A-61-167681. There is. It has been known that these compounds have an absorption band with a large absorption intensity in the wavelength band of 750 to 900 nm, and thus have a good absorption efficiency for infrared laser light and a good heat conversion efficiency for absorbed light. By the way, when the inventors of the present invention adopted these compounds as an infrared absorbing agent for the recording sheet, the coating liquid was easy to prepare due to their large solubility in the solvent used for the thermal transfer recording sheet, and especially for dyes. There is no adverse effect, the storage stability of the coating liquid and transfer sheet is good, and the thermal transfer property is very small compared to dyes, and it is transferred to the image receiving paper itself even in high-speed recording where high thermal energy is applied. The present invention has been completed by finding out that the image quality does not deteriorate and the recording image quality does not deteriorate.

[0011]

[Table 1]

Next, the transfer sheet of the present invention will be described. In the transfer sheet of the present invention, the layer containing the infrared absorbing substance may be formed at any position of the base film, but it is formed on the same side as the coloring material layer containing the heat transferable dye. Is more preferable, and it is more preferable to use it by mixing it with a dye in the color material layer.

In the case of forming a coloring material layer containing an infrared absorbing material in the coloring material layer, an ink is prepared by dissolving the infrared absorbing material together with a dye and a binder in a medium or dispersing it in the form of fine particles. Apply ink to the base film,
It can be carried out by drying. As the binder for preparing the ink, cellulose-based, acrylic acid-based,
Starch-based and epoxy-based water-soluble resins and acrylic resins, methacrylic resins, polystyrene, polycarbonate, polysulfones, polyether sulfones, polyvinyl butyral, ethyl cellulose, acetyl cellulose,
Examples thereof include resins soluble in organic solvents such as polyester, AS resin, and phenoxy resin.

As a medium for preparing the ink, in addition to water, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and isobutyl alcohol, cellsolves such as methyl cellosolve and ethyl cellosolve, and aromas such as toluene, xylene and chlorobenzene. Group, esters such as ethyl acetate and butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, methylene chloride,
Chlorine solvents such as chloroform and trichlorethylene,
Ethers such as tetrahydrofuran and dioxane,
Organic solvents such as N, N-dimethylformamide and N-methylpyrrolidone can be mentioned.

The heat transferable dye may be any as long as it can be transferred to the receiving layer by the action of heat, and azo dyes and anthraquinone dyes which have been proposed for heat-sensitive transfer sheets for conventional thermal heads. Dyes, azomethine dyes, methine dyes, indoaniline dyes, quinophthalone dyes and the like can be used. Infrared absorber,
The amount of the dye and the binder used is 1 to 200% by weight, preferably 10 to 10% by weight of the infrared absorber with respect to the dye.
0% by weight, and 10 to 500% by weight, preferably 50 to 200% by weight, of the pigment is suitable for the binder.

In the above ink, in addition to the above components, if necessary, organic or inorganic non-sublimable fine particles, a dispersant, an antistatic agent, an antifoaming agent, an antioxidant, a viscosity modifier, a release agent. Etc. can be added. The thickness of the color material layer is 0.1 to 10 μm
Is suitable, and preferably 0.5 to 5 μm.

As the base film of the transfer sheet, a film of transparent plastic having good heat resistance such as polyester, polycarbonate, polyamide, polyimide, polyaramid is suitable, and the thickness thereof is in the range of 3 to 200 μm. I can name it. Of the above base films, the polyethylene terephthalate film is particularly advantageous in consideration of mechanical strength, solvent resistance, economy and the like.

In the transfer sheet of the present invention, a dye-permeable protective layer may be further formed on the color material layer, if necessary. As a method for applying the ink to the base film, a gravure coater, a reverse roll coater, a rod coater, an air doctor coater or the like can be used.

[0019]

The present invention will be described in detail with reference to the following examples, but the examples do not limit the present invention. Example 1 a) Preparation of ink

[0020]

[Chemical 3]

The mixture having the above composition was treated with a paint conditioner for 10 minutes to prepare an ink.

B) Preparation of transfer sheet The above ink was applied onto a polyethylene terephthalate film (6 μm thick) using a wire bar and dried (dry film thickness of about 1 μm) to obtain a transfer sheet.

C) Preparation of image receptor 10 parts of vinyl chloride / vinyl acetate resin (product name: VYHD; Union Carbide product), amino-modified silicone (product name: KF-3)
93; Shin-Etsu Chemical Co., Ltd. product) 0.5 part, methyl ethyl ketone 15 parts, xylene 15 parts liquid synthetic paper (Product name: Yupo FPG150; Oji Yuka Co., Ltd. product)
Apply with a wire bar and dry (dry film thickness about 5 μm),
Further, it was produced by treating at 80 ° C. for 30 minutes in the open.

D) Transfer recording The transfer sheet is laminated so that the ink-coated surface of the transfer sheet is in contact with the surface of the receiving layer of the image receptor, and is wound on a drum having a diameter of 250 mm so that the image receptor is in contact with the drum (vacuum is sucked from the inside of the drum. Furthermore, a transparent cover film of polyethylene terephthalate having a thickness of 25 μm was attached on the transfer sheet so that the transfer sheet and the image receiver closely adhered to each other.) While rotating the drum, the transmission wavelength of 830
Transfer recording was performed under the following conditions while continuously irradiating a semiconductor laser beam of nm.

Equipment used: Model No. LN98100PR manufactured by Matsushita Electric Industrial Co., Ltd. Drum rotation speed: 500 rpm Laser light output: 80 mW Laser light spot diameter: 4 μm Recording line density: 100 / mm Uniform by transfer recording under the above conditions A clear and magenta-colored recorded product was obtained. The result of measuring the color density of the recorded matter using a densitometer TR-927 manufactured by Macbeth Co. 1.2
It was 5.

Example 2 In the same manner as in Example 1 except that 8 g of the following dye (C) was used in place of the dye of Example 1 in the preparation of ink, the ink was prepared, the transfer sheet was prepared, and the image was received. Body production and transfer recording were carried out to obtain a uniform and clear yellow recorded matter having a color density of 1.30.

[0027]

[Chemical 4]

Example 3 In the same manner as in Example 1 except that 8 g of the following dye (D) was used in place of the dye of Example 1 in the preparation of ink, the ink was prepared, the transfer sheet was prepared, and the image was received. The body was prepared and transfer recording was carried out to obtain a uniform and clear cyan color recorded product having a color density of 1.20.

[0029]

[Chemical 5]

Example 4 In the preparation of ink, 0.2 g of true spherical silicone resin particles (average diameter 2 μm) was added to the components of Example 1 to prepare an ink, and a transfer sheet was prepared and an image receptor was prepared. And the transfer recording are performed in the same manner as in Example 1, and the color density is 1.20.
A uniform and vivid magenta-colored recorded matter was obtained.

Example 5 A transfer sheet was prepared by further coating an aqueous solution of polyvinyl alcohol on the color material layer of the transfer sheet prepared in Example 1 to form a protective layer having a thickness of about 0.1 μm. Using this transfer sheet, transfer recording was performed in the same manner as in Example 1 to obtain a uniform and vivid magenta color recorded product having a color density of 1.15.

Example 6 Instead of the infrared absorber of Example 1 in the preparation of the ink,
Ink was prepared, a transfer sheet was prepared, an image receptor was prepared and transfer recording was carried out in the same manner as in Example 1 except that 2 g of the infrared absorbent shown in Table 2 was used. I got a record.

Comparative Example Instead of the infrared absorber of Example 1 in the preparation of the ink,
Ink preparation, transfer sheet preparation, image receptor preparation and transfer recording were carried out in the same manner as in Example 1 except that 2 g of the infrared absorbent shown in Table 2 was used, and the results shown in Table 2 were obtained.

[0034]

[Table 2]

[0035]

When the heat-sensitive transfer sheet of the present invention is used, a semiconductor infrared laser can be used as a heating means to obtain a high density and clear recorded matter.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Urano Sanboshi Kasei Co., Ltd. Research Institute, 1000 Kamoda-cho, Midori-ku, Yokohama-shi, Kanagawa

Claims (1)

[Claims] 1. A sheet having a layer containing a heat transferable dye and an infrared absorbing substance on a base film, which is used for thermal transfer recording using infrared rays as a heating means, wherein the infrared absorbing substance has the following general formula (I): ) [Chemical 1] (In the formula, R represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and n represents 0, 1, or 2.) An infrared heating type thermal transfer recording characterized by being a squarylium compound. Sheet.