JPS6223783A - Thermal transfer recording method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal transfer recording method, and in particular to a method for forming a thermal transfer material on the spot and continuously recording without contaminating the recording medium. The present invention relates to a thermal transfer recording method.

[Prior art]

In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording methods and devices suitable for each information processing system have also been developed and adopted.

As one of such recording methods, the thermal recording method has been widely used recently because the equipment used is light or uranium/4', noiseless, and has excellent operability and maintainability. .

However, among the recording papers used in thermal recording methods, ordinary thermal recording paper is a color-forming processed paper containing a color former and a color developer, so it is expensive, and records can be tampered with. The paper has disadvantages in that it has poor storage stability, such as the paper being easily colored by heat or organic solvents, and the recorded image fading in a relatively short period of time.

In recent years, a thermal transfer recording method has been attracting particular attention as a method that maintains the advantages of the above-mentioned thermal recording method and compensates for the drawbacks associated with the use of thermal recording paper.

FIG. 4 is a diagram for explaining an example of a heat-sensitive transfer material used in the above-mentioned heat-sensitive transfer recording method, and is a schematic cross-sectional view in the thickness direction of the heat-sensitive transfer material.

As shown in Figure 4, thermal transfer materials are generally made by melt-coating thermal transfer ink, which is made by dispersing a coloring agent in a heat-melting inder, onto a support 1 made of sheet-like paper, plastic film, etc. A thermally transferable ink layer 2 is formed by doing this.

The thermal transfer recording method involves superimposing this thermal transfer material on a recording medium such that the thermal transferable ink layer 2 is in contact with the recording medium,
A transfer ink image corresponding to the shape of the heat supply is formed on the recording medium by applying heat from the support side of the thermal transfer material using a thermal head to transfer the melted ink layer onto the recording medium.

According to this method, it is possible to maintain the above-mentioned advantages of the thermal recording method and to use it as a normal recording medium, and also to eliminate the disadvantages associated with the use of the thermal recording paper described above.

[Problem that the invention seeks to solve]

However, even in a thermal transfer recording method having such excellent characteristics, there are still some points that require improvement. For example, the manufacturing process of the thermal transfer material used is quite complex. Furthermore, since this thermal transfer material is essentially disposable, recording costs are high.

In order to eliminate the above-mentioned drawbacks, it has been proposed to use an endless belt-like support for the heat-sensitive transfer material and to incorporate the manufacturing process of the heat-sensitive transfer material by conventional heat-melting coating into a heat-sensitive transfer recording system.

However, in this case, it is necessary to maintain the hot-melt ink in a molten state while heating it, which not only increases energy loss but also makes it mechanically complex. In addition, in order to precisely control the thickness of the heat-melt ink layer by coating, the ink used is heat-melt and therefore its viscosity changes greatly depending on temperature, so it is necessary to control the temperature of the melted ink as well as the coating area. It is necessary to strictly control the temperature, which poses various practical difficulties. Furthermore, there are disadvantages in that the recording medium is stained and the transferred image becomes unclear due to insufficient cooling after the thermal transferable ink layer is formed.

[Means for solving problems]

According to the research conducted by the present inventors, in order to solve the above-mentioned problems, a liquid ink was used as a substitute for the heat-melting ink, and after being coated on a support, the coated surface was communicated in the layer thickness direction. It has been found that it is extremely effective to form a thermally transferable ink layer by superimposing porous films having pores.

The thermal transfer recording method for a thermal transfer material of the present invention is based on the above-mentioned knowledge, and more specifically, the following steps (a) to (e) are sequentially and repeatedly carried out on an endless support. This is a thermal transfer recording method characterized by the following.

(B) Process frame of applying liquid ink to the support surface) A process of superimposing a porous film having endless pores communicating in the thickness direction on the liquid ink-applied surface.The porous film on the support faces the film surface. (e) separating the support and the porous film from the recording medium; Step of leaving a liquid image on top according to heating/lean conditions [Example] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a schematic cross-sectional view in the thickness direction of a heat-sensitive transfer material in the most basic embodiment manufactured and used in the recording method of the present invention. That is, the thermal transfer material has a liquid ink layer 12 on a support 1, and further has pores 1 communicating in the layer thickness direction.
4 (hereinafter simply referred to as porous film) 3 is coated thereon.

FIG. 1 shows an embodiment B of the thermal transfer recording system according to the method of the present invention, and is a schematic cross-sectional view in the thickness direction of the support.

That is, an endless belt-shaped support 1 that is continuously moved around the circumference υ of the rolls 4a, 4b, 4c, and 4d.
Then, the liquid ink 1] in the ink reservoir 5 is applied using a coating machine F consisting of a pair of coating rolls 6 and a doctor blade 7 to form a liquid ink layer 12. Next, a porous film 3 is spread over this liquid ink layer 12 to form a heat-sensitive transfer material. A recording medium 8 made of plain paper or the like is brought into contact with the porous film 3 of the heat-sensitive transfer material, and heat is supplied by a thermal head 10 at a position facing the platen roll 9 according to a desired arm turn.

Next, when the recording medium 8 leaves the g-thermal transfer material, the recording medium 8
A porous film 3 is placed on top according to the applied fAi4' turn.
At the same time, the desired ink pattern 13 transferred is left behind. On the other hand, the ink and porous film laminate remaining on the support 1 are separated from the support. At this time, a portion of the remaining ink remains attached to the support and is sent to the ink application section, where the liquid ink is uniformly coated again and subjected to the series of steps described above.

A spacer may be provided on the support 1 or the porous film 3 in order to keep the liquid ink layer 12 constant in layer thickness.
Alternatively, the liquid ink layer 12 may be constructed by absorbing the liquid ink 11 into an endless porous belt.

Next, the configuration of each part shown in the drawings will be explained.

As the support 1, conventionally known films and papers having the necessary strength, heat resistance, and flexibility can be used as they are, such as plastics such as polyamide, polyimide, polycarbonate, and triacetyl cellulose. Film, cellophane, parchment paper, etc. can be suitably used.

The thickness of the support is preferably about 2 to 15 microns when considering a thermal head as a heat source during thermal transfer, but it is possible to selectively heat the ink layer and thermoplastic film layer using, for example, a laser beam. There are no particular restrictions when using a heat source. In addition, when using a thermal head, by providing a heat-resistant protective layer made of silicone resin, fluororesin, polyimide resin, epoxy resin, phenol resin, melamine resin, nitrocellulose, etc. on the surface of the support that comes into contact with the thermal head. The heat resistance of the support can be improved, or a support material that could not be used conventionally can be used. Moreover, the support body 1 can be multi-layered as necessary for reinforcement.

The liquid ink 11 is prepared by dissolving or dispersing coloring materials such as dyes and pigments in liquid substances such as water, animal and vegetable oils, mineral oils, ester compounds, and ether compounds, and adjusting the viscosity by adding resin as necessary. Use. Writing ink, typewriter ribbon ink, printing ink, etc. are preferably used.

The liquid ink 11 is of low/l as illustrated in FIG.
/ Near-p-,, Rirui is a blade coater,
It is applied onto the support 1 using a bar coater or the like. The coating thickness is usually 0.5 to 20 μm, preferably 1 to 10 μm.
is within the range of

The porous film 3 laminated on the liquid ink Jim 12 is made of a film-forming material, whether thermoplastic or thermosetting, such as polyurethane; polyamide, polyimide, polyester, polyvinyl chloride, polyolefin, etc.; The method of coating is not particularly limited, but for example, immediately after coating a coating solution in which a thermoplastic resin such as a polyurethane resin is dissolved in a solvent mainly composed of trimethylformamide on a base material such as release paper. It is obtained by replacing the solvent with water to insolubilize and precipitate, dry, and peel off from the base material. The layer thickness of this porous film 3 is preferably 1 to 50 μm, more preferably 2 to 20 μm. The average diameter of the pores 14 is preferably 1 to 100 μm, more preferably 2 to 50 μm.

The liquid ink layer 12 is sandwiched between the porous film 3 and the support 1, and is stably held in a thin film form by interfacial tension.

Support 1. Liquid ink layer 12. The heat-sensitive transfer recording process using a heat-sensitive transfer material constituted by the porous film 3 is not particularly different from a normal heat-sensitive transfer recording method, and for example, FIG. 3 shows the case where a thermal head is used.

FIG. 3 is a schematic sectional view in the thickness direction of a thermal transfer material showing its outline. That is, the recording medium 8 is brought into close contact with the porous film 3 of the thermal transfer material, and if necessary, the thermal head 10 is further supported from the back side of the recording medium 8 by a platen 9'.
The liquid ink layer 12 penetrates into the pores 14 due to the pressure from the thermal head 10 and the platen 9', and is ejected from the pores 14 by the heat from the thermal head, and is applied to the recording medium 8. to leave a recorded image.

In this embodiment, a thermal head is used as a heat source for supplying heat according to the recording pattern to the thermal transfer material.
In addition to the thermal head, for example, the aforementioned laser light or the like can be suitably used.

〔Effect of the invention〕

As described above, according to the present invention, there is a step of providing a liquid ink layer on a support and further forming a multi-thermal transferable ink layer by folding a porous film layer having pores communicating in the layer thickness direction. An integrated thermal transfer recording method is provided.

Therefore, the following great advantages can be obtained compared to the case where a heat transferable ink layer forming step by conventional hot bath melt coating is incorporated. That is, (a) it is not necessary to supply a large amount of heat required for thermal melt coating, so the energy of the entire thermal transfer recording system is saved.

(b) Since the thermally transferable ink layer is composed of liquid ink rather than heat-melting ink, temperature control during coating is virtually unnecessary.

(c) Staining of the recording medium and blurring of the transferred image due to insufficient cooling after the formation of the thermally transferable ink layer can be prevented.

B) Since the ink layer is liquid at room temperature, the transferability to the recording medium is better than that of heat-melting inks.

(E) The penetration of liquid ink into the recording medium depends on the formulation)
Can be controlled arbitrarily.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view in the thickness direction of a support, showing an outline of a thermal transfer recording system according to the method of the present invention. FIG. 2 is a schematic sectional view in the thickness direction of a thermal transfer material formed and used in the present invention. FIG. 3 is a diagram illustrating an outline of an embodiment of the thermal transfer recording method according to the present invention. FIG. 4 is a schematic cross-sectional view in the thickness direction of a conventional heat-sensitive transfer material using hot bath-meltable ink. 1... Support body, 3... Porous film, 4m, 4b
. 4c, 4d...roll, 5...ink reservoir, 7.
... Doctor blade, 8 ... Recording medium, 9 ... Platen roll, 10 ... Thermal head, 11 ... Liquid ink, 12 ... Liquid ink layer, 13 ... Ink arm turn.

Claims (1)

[Scope of Claims] A thermal transfer recording method characterized by sequentially and repeatedly performing the following steps (a) to (e) on an endless support. (B) Step of applying liquid ink to the support surface (B) Step of superimposing a porous film having endless pores communicating in the layer thickness direction on the surface coated with liquid ink (C) Said porous film on the support surface Step of superimposing the recording medium so as to face the surface (d) Step of heating the liquid ink layer facing the recording medium and the porous film in a pattern (e) Separating the support and the porous film from the recording medium The process of leaving a liquid image on the recording medium according to the heating pattern.