JPS60190390A - Thermal transfer printing material - Google Patents

Abstract

PURPOSE:To provide the titled material which is excellent in the anti-sticking property even under a high applied voltage and a platen pressure by arranging nitrocellulose and acetocellulose in a heat resistant protective layer on the back of a heat-softening plastic film at a specified rate. CONSTITUTION:Optimally, a carbon ink layer (e.g. paraffin wax) is arranged on the surface of a heat-softening plastic film 2 of polyethylene terephthalate and nitrocellulose and acetocellulose are blended on the back thereof at the ratio by weight of 12:1-12:5, preferably 6:1-6:2. Then, a heat resistant protective layer 3 is provided at the thickness of 0.5-5mum, preferably 1-2mum to obtain the desired material.

Description

[Detailed description of the invention] The present invention relates to thermal transfer materials.

In recent years, thermal transfer paper has been used for printing in facsimiles, word processors, computers, etc.

General thermal transfer paper has a carbon ink layer placed on a thin plastic film. When the plastic film is printed with a thermal head, the film melts and the ink is transferred onto the paper placed on the carbon ink layer. The practical problem with thermal transfer materials is that in order to obtain clear transferred images, it is necessary to reduce the thickness of the transfer material as much as possible, so the plastic film must be made thinner. It can fuse to the thermal head and cause sticking, which can impede the running of the transfer paper and even damage the print head.

To solve this problem, on the plastic film,
Proposals have been made to provide a protective M layer. For example, JP-A-5
No. 5-7467 discloses silicone resin as a protective figure,
Epoxy resin, melamine resin, phenolic resin, fluororesin, polyimide resin, and nitrocellulose are disclosed, but when these resins are used as a protective layer, the voltage applied to the thermal head is low and the platen pressure is weak. Regardless of the case, if the applied voltage is high and the platen pressure is high, fusion to the thermal head occurs and the protective function cannot be fully achieved.

Furthermore, JP-A-58-171992 discloses that resins having a glass transition point of 60° C. or higher, such as acrylic resins, polyester resins, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate, and nylidene fluoride resins are used as the protective layer. It is disclosed that nylon, polyvinyl carbazole, chlorinated rubber, carbonized rubber and polyvinyl alcohol can be used. however,
Even with these resins, a satisfactory protective function is not achieved.

The present inventors have found that using a combination of nitrocellulose and cellulose acetate in a specific ratio as the material for this protective layer exhibits excellent anti-sticking ability even when high applied voltage and platen pressure are applied. was investigated.

That is, as shown in FIG. 1 (cross-sectional view of thermal transfer material), the present invention provides a heat-adhesive plastic film (2) with a carbon ink layer (1) on the surface and a heat-resistant protective layer (3) on the back surface. The present invention relates to a thermal transfer material, wherein the heat-resistant protective layer contains nitrocellulose and cellulose acetate in a weight ratio of 12:1 to 12:5.

The carbon ink layer (1) and heat-adhesive plastic film (2) used in the present invention may be those commonly used in conventional heat-sensitive transfer materials.

The carbon ink layer (1) may be any ink that can be melted and transferred by heating, and a wax having an appropriate melting point, such as paraffin wax, microcrystalline wax, carnauba wax, etc., may be used as a binder, and carbon black or It is a mixture of coloring agents such as various dyes and pigments.

Examples of the heat-softening plastic film (2) include polyethylene terephthalate, polyester film, polycarbonate film, triacetyl cellulose film, etc., but polyethylene terephthalate is particularly preferred since it has good heat resistance and can yield an extremely thin film. It is. This heat-fusible plastic film should be as light as possible as long as its strength allows. When polyethylene terephthalate is used, a thin film of about 4 μm can be obtained.

The heat-resistant protective layer (3) is made of a mixture of nitrocellulose and cellulose acetate in a weight ratio of 12:1 to 12:5. More preferably the ratio is 6:1 to 6:2. Whether the blending ratio is greater or less than this, a satisfactory anti-sticking effect cannot be obtained. Further, it is particularly preferable that the weight ratio of nitrocellulose to cellulose acetate is in the range of 6:1 to 6:2 because no sticking phenomenon occurs even when high applied voltage and platen pressure are applied. From the viewpoint of solubility in solvents, cellulose acetate preferably has a degree of acetylation of 55% and an average degree of 5-polymerization of 140 to 180.

Although there are no particular regulations regarding the nitrocellulose, from the viewpoint of coating properties depending on the viscosity of the solution, it is preferable to use a cellulose having a falling ball viscosity of 24 seconds or less in a 12.2% JIS solvent solution.

21-mouth cellulose and cellulose acetate are dissolved in a suitable solvent, such as a mixed solvent such as nitropropane, ethyl acetate, butyl acetate, nitromethane, methylene chloride, acetone, etc., and the film thickness after drying is 0.5 to 5 μm1.
In particular, it is coated to a thickness of 1 to 2 μm. If it is smaller than 0.5 μm, it will not function as a heat-resistant protective layer, and if it is larger than 5 μm, the clarity of transfer by the heat-sensitive transfer material will be insufficient. Usually, a satisfactory effect can be obtained with a thickness of 1 to 2 μm. The mixed solution of nitrocellulose and cellulose acetate may be coated on a heat-softening plastic film using, for example, a graphia coater, a flexo coater, a mare bar coater, a reverse roll coater, a slot coater, or the like, and then dried.

61 The thermal transfer material of the present invention may be used in the form of a narrow tape or sheet, such as a typewriter ribbon, or a wide tape or sheet, such as a line printer ribbon.

The present invention will be explained below with reference to Examples.

Nitrocellulose and cellulose acetate were mixed according to the formulation shown in "-" and Comparison Table-1. The dry solid content of this mixed solution is approximately 1 (
]/m2 using 3-bar coating method, 4μm
Polyethylene terephthalate film (manufactured by Diafoil Co., Ltd.) was coated on the film. After drying this film at 40'C, carbon ink having the following formulation was applied to the opposite side.

Prescription Suspended Part Carnauba Wax 40 Ester Gum 5 Parafine Wax 35 Carbon Black 20 Application was carried out using a smoothing bar application method to approximately 39/m2 while maintaining the temperature at 90°C.

The carbon ink layer (1) of the obtained thermal transfer material was 3.
The thickness of the heat-resistant protective layer was 1 μm.

The carbon black-coated side of this thermal transfer material is coated with receiver paper (
For example, 64/m2, high-quality paper) was stacked, and transfer printing was performed with the thermal head in contact with the heat-resistant protective layer to evaluate the anti-stinging property. The applied voltage and platen pressure were as follows, and the obtained results are shown in Table 1.

Applied voltage: Printer A 10V Printer B 18V Platen pressure Printer A 1000 Printer B
400a

[Brief explanation of drawings]

FIG. 1 is a sectional view of the heat-sensitive transfer material of the present invention. In the figure, (1) shows the carbon ink layer, (2) shows the heat-softening plastic film, and (3) shows the heat-resistant protective layer. 10- Figure 1 Procedural amendment (indication of self-control case Patent Application No. 48663 of 1988 2, name of the invention Thermal transfer material 3, person making the amendment Relationship with the case Patent applicant address Fukushima Ward, Osaka City, Osaka Prefecture) 8-10-1 Ebie Name: Naigai Ink Manufacturing Co., Ltd. Representative Shigeru Kawa 4, Agent 5 Date of amendment order (voluntary) 6 Subject of amendment AMJi's "Detailed weakness of the invention' 4-
．． ilQ et al.-7, Contents of the amendment (1) Page 2 of the specification, lines 6-7, the statement "The film melts when stamped with a head" is replaced with "When applied to a printer"
Correct. (2) On the 2nd page, line 8 from the bottom, the word "transfer paper" is corrected to "thermal head." (3) On the 2nd page, line 7 from the bottom, everything that says "Print"
corrected to "Thermal". (4) On the 3rd page, line 8 from the bottom, all the words “Carbonized rubber” are “
Corrected to "cyclized rubber." (5) On page 4, lines 9-10, the term “thermal adhesiveness” has been replaced with “
Corrected to ``heat softening''. (6) On page 5, line 6, "thermal adhesive" is corrected to "thermal softening". (7) On page 6, line 9 of the same page, insert ", ethanol" in its entirety after "acetone." Above - (2)

Claims (1)

[Claims] 1. In a heat-sensitive transfer material having a carbon ink layer (1) on the surface of a heat-softening plastic film (2) and a heat-resistant protective layer (3) on the back surface, the heat-resistant protective layer comprises nitrocellulose and cellulose acetate. 1. A heat-sensitive transfer material comprising: a weight ratio of 12=1 to 12:5. 2. The weight ratio of nitrocellulose and cellulose acetate is 6:
2. The thermal transfer material according to claim 1, wherein the ratio is 1 to 6:2. 3. The heat-sensitive transfer material according to 11, wherein the thickness of the retention layer m is 0.5 to 5 μm. 4. The heat-sensitive transfer material according to item 1, wherein the protective layer has a thickness of 1 to 2 μm. 5. The heat-sensitive transfer material according to item 1, wherein the plastic film is polyethylene terephthalate.