JPS59138493A - Transfer medium for heat-sensitive recording - Google Patents

Abstract

PURPOSE:To enhance thermal conductivity and thereby contrive to enhance recording speed and print quality, by a method wherein a particulate good heat conductor is embedded into a base film on at least one side of the film, and a heat-fusible ink layer is provided on that side or the other side. CONSTITUTION:A large quantity of particulates of a metal such as copper, aluminum or zinc is dispersed into a binder such as a polyimide resin, a phenoxy resin, a fluoro resin, a polysulfone resin or a polyester resin, and the resultant material is applied onto the base film. To embed the particulates of the metal into the base film, the particulates are dispersed into the binder while setting the volume of the particulates to be larger than that of the binder, and the particulates are sufficiently embedded into the base film and are smoothened, e.g., by a method wherein the film is passed a few times between calender rolls while heating one of the rolls and exerting a pressure on a contact part. The thus obtained transfer medium for heat-sensitive recording is capable of transferring with an apparently small quantity of energy.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a thermal recording transfer medium used in recording devices such as facsimiles and word processors.

BACKGROUND OF THE INVENTION An IN film provided with a heat-melting ink layer on one side is generally used as a transfer medium for thermal recording.

To perform recording using the above transfer medium, the ink layer is brought into contact with the material to be transferred, the base side is placed opposite to the heat generating head,
By supplying electricity to the heat-generating head, the heat-generating head generates heat, and the ink layer is melted by the heat and transferred onto the transfer material.

In this case, a coating layer mainly containing an inorganic pigment and a binder is provided to prevent sticking, but such a coating has a drawback of low thermal conductivity. In addition, in order to improve the decrease in thermal conductivity, there is a proposal to add an intermediate layer consisting of a metal powder that is a good thermal conductor and a binder, but it is difficult to contain a large amount of metal powder, and the thermal conductivity There are limits to sexual improvement.

Purpose: The purpose is to improve the thermal conductivity of transfer media for thermal recording, thereby improving recording speed and print quality.

Structure The present invention is a transfer medium for heat-sensitive recording, characterized in that a fine thermal conductor is embedded in at least one side of a base film, and a heat-melting ink layer is formed on that side or the opposite side.

To make such a transfer medium, a binder agent such as polyimide resin, phenoxy resin, fluororesin, polysulfone resin, or polyester resin is mixed with a large amount of a powdered good conductor of heat, such as metal powder such as copper, aluminum, or lead. This is done by dispersing the powder into the base film, applying it to the base film, and embedding the thermally conductive powder into the base film under heat and pressure to smooth the surface. In this case, in order to embed the good conductor powder into the base film under pressure, the heated good conductor powder must form irregularities on the coated surface after the dispersion is applied. For this purpose, it is necessary to use a powder that is dispersed in a volume of good thermal conductor powder that is larger than the volume of the binder agent.

If a heat-resistant binder is used, a heat-resistant layer will be formed on the surface of the surface where the thermally conductive powder is embedded, so if a heat-fusible ink layer is provided on the opposite side, This also provides an excellent 1F sticking prevention effect during recording.

When a heat-melting ink layer is provided on the surface in which the thermally conductive powder is embedded, it is not necessary to use a heat-resistant resin as the binder agent.

The size of the thermally conductive powder is preferably about 1.about.20 .mu.m.

Next, examples will be described.

Example: Heat-resistant polyimide resin (trade name) was used as a binder agent.
Polyimide 2080D HV (manufactured by Mitsubishi Kasei Co., Ltd.) and 3-5 μm copper powder (reagent, manufactured by Kanto Kagaku Co., Ltd.) as a good thermal conductor powder are used, and these are dispersed at a ratio of 80% to 80% to form a dispersion liquid.

A polyester film with a thickness of 16 μm was used as the base film, and one side of the film was coated with the above dispersion to a thickness of 10 μm, dried in an atmosphere of 120°C, calendered, and copper powder was applied. embedded in the film. At this time, roll one side of the calender roll to 70-80
While heating to ℃, a pressure of 300 kg/cm is applied to the contact area of the calender. Pass the film through the calender 5 times to fully embed the copper powder into the film.

A heat-melting ink having the composition shown below is applied to a thickness of about 5 μm on the opposite side of the base film to the coated side. The unit is parts by weight.

[Hot melt ink composition] Carnauba wax 100 Microcrystalline wax 30 Vinyl acetate-ethylene copolymer 15 Carbon black
20 Comparative Example Same as the example, polyimide resin was used as a heat-resistant binder agent,
Copper powder of 3 to 5 μm is used as the metal powder, and both are mixed and dispersed at a weight ratio of 1:5.

This was applied to a 16 μm thick polyvinyl film with a thickness of 10 μm.
After coating the film to a thickness of The same heat-melting ink layer as in the example is formed on the opposite surface to this coated surface.

Effects The thermal recording transfer media of Examples and Comparative Examples were subjected to a thermal transfer tester to measure the amount of energy during transfer. Commercially available high-quality paper (thickness: approximately 60 μl1) was used as the transfer paper. The evaluation was performed based on the amount of energy (amount of electrical energy supplied) when complete transfer was performed, and the results were 0.8 mJ for the example and 1.2 mJ for the comparative example, and the present invention was better. It is clear that the transfer takes place with a small amount of energy.

Furthermore, in the embodiment, since a heat-resistant film is formed on the surface of the film that comes into contact with the thermal head, this also prevents the film from sticking.

Furthermore, there is no fear that the thermally conductive surface will peel off, unlike in the conventional case.

Patent applicant Rico Co., Ltd. Agent: Patent attorney: Hidetake Komatsu 6-

Claims (1)

[Claims] (A transfer medium for thermal recording, characterized in that a fine thermal conductor is embedded in at least one side of a 11MU film, and a heat-melting ink field is formed on the opposite side.