JP3273150B2 - Thermal transfer recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording method,
More specifically, the present invention relates to a multicolor thermal transfer recording method in which occurrence of image shift and wrinkles of a thermal transfer recording medium conveyance is prevented.

[0002]

2. Description of the Related Art Among recording apparatuses such as printers and facsimile machines, those utilizing a thermal transfer recording system are widely used as those which can reduce the size, cost and maintenance of the recording apparatus. In addition, this method has attracted attention in recent years because multicolor recording can be performed relatively easily by using a multicolor thermal transfer recording medium (ink sheet or ink ribbon).

As a method of obtaining a multicolor image by a thermal transfer recording method, an image of each color is melt-transferred onto plain paper using an ink sheet of each color of yellow, magenta, cyan and, if necessary, black, and the color is transferred. A method of obtaining a desired multicolor image by superposition is generally used. However, this method has a drawback that image misalignment and defective feeding / discharging of the ink sheet often occur.

Therefore, in order to solve this image shift, a thermal transfer ink sheet having a dynamic friction coefficient between two types of ink surfaces of 0.70 or more (Japanese Patent Laid-Open No. 62-275780) and a thermal transfer ink sheet are disclosed. A method using a heat transfer sheet and a heat transfer sheet having a coefficient of friction of 0.40 or more between the receiving layer surface and the color material layer surface of the heat transfer sheet
No. 236690) has been proposed.

[0005]

However, even if such a thermal transfer ink sheet (and a thermal transfer sheet) is used, it is sufficiently satisfactory in that the image shift and the occurrence of wrinkles in the transfer of the thermal transfer ink sheet are still prevented. It was not something to be done.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a thermal transfer recording method capable of smoothly transporting a thermal transfer recording medium and obtaining a clear multicolor image without image shift.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to overcome the above-mentioned problems when performing overprinting on receiving paper (heat transfer sheet) by a thermal transfer recording method. By using the receiving paper and the thermal transfer recording medium in which the difference in the coefficient of static friction between the paper surface and the primary color image surface is within a specific numerical range, the thermal transfer recording medium runs smoothly and is suitable without image misalignment. The present inventors have found that an excellent transfer image can be obtained, and have reached the present invention.

That is, according to the present invention, in a thermal transfer recording method for performing multicolor printing using a thermal transfer recording medium, the surface of the primary color image surface on which the secondary color printing is performed and the mark on the surface of the receiving paper.
A thermal transfer recording method is provided in which secondary color printing is performed under a combination in which the difference in the coefficient of static friction with the surface on which the character is formed is 0.3 or less.

In the present invention, the coefficient of static friction between the surface of the receiving paper and the surface of the primary color image is defined as "a fully automatic friction-wear analysis apparatus /
DFRM-SS type ".

Hereinafter, the present invention will be described in more detail. The state of implementation of this recording method is shown, for example, in FIG. In FIG. 1, a receiving paper 1 is conveyed in the direction of the arrow by rollers 4 and 5, and a primary color image portion 2 is placed on the receiving paper 1 by a heat transfer recording medium (ink ribbon) 8 by heat from a thermal head 6.
Printed with. Subsequently, the receiving paper 1 is further conveyed in the direction of the arrow, and the secondary color image portion 3 is about to be printed on the primary color image portion 2 by the ink ribbon 9 by the heat from the thermal head 7.

At this time, in the present invention, the receiving paper 1 and the ink ribbon 8 are set so that the difference between the surface static friction coefficient of the receiving paper 1 and the surface static friction coefficient of the primary color image 2 becomes 0.3 or less. It is characterized by using. By using such a receiving paper and ink ribbon, there is no significant difference between the static friction resistance on the receiving paper surface and the static friction resistance on the image surface, so that either the receiving paper surface or the image surface can be avoided. On the other hand, no positional deviation due to slippage and no generation of transport wrinkles occur.

The thermal transfer recording medium used in the present invention has a structure in which a release layer and a heat-meltable ink layer are laminated on a support in this order, and the structure is shown in FIG. 2, for example. In FIG. 2, 11 is the support, 12 is the release layer and 1
Reference numeral 3 denotes a heat-fusible ink layer.

Further, the thermal transfer recording medium used in the present invention preferably has the above-mentioned structure and has the following release layer having a release layer made of a specific material. (1) A release layer whose main component is an elastomer and an organic lubricant. (2) A release layer whose main component is an elastomer, an organic lubricant and a thermoplastic resin. By using the above-mentioned thermal transfer recording medium, it is possible to improve the cut of the image or reduce the void.

As the elastomer used in the release layer of the thermal transfer recording medium used in the present invention, an unvulcanized rubber is particularly preferred. As the unvulcanized rubber in this case, polyisoprene, polybutadiene, styrene butadiene rubber, nitrile rubber, ethylene propylene rubber, butyl rubber, silicone rubber, fluorine-based rubber, urethane rubber, and the like, preferably polyisoprene, polybutadiene, ethylene propylene rubber, Butyl rubber and nitrile rubber. These preferred rubbers have a melting point of 60 ° C to 200 ° C.

The organic lubricant used in the release layer includes:
Waxes such as carnauba wax, candelilla wax, natural wax such as beeswax, wood wax, montan wax, and spermaceti, and synthetic waxes such as paraffin wax, microcrystalline wax, oxidized wax and polyethylene wax; margaric acid, lauric acid,
Higher fatty acids such as mistyric acid, palmitic acid, stearic acid, fluorenic acid and behenic acid and derivatives thereof and metal salts; higher alcohols such as stearyl alcohol and behenyl alcohol; esters such as fatty acid esters of sorbitan; stearic acid amide, oleic acid amide And the like. Among them, waxes, particularly carnauba wax, montan wax and high-density polyethylene wax; higher fatty acids and derivatives thereof are preferred.

The thermoplastic resin used in the release layer may be polyamide, polyester, polyurethane, or the like.
In addition to vinyl chloride, cellulose, petroleum, styrene, butyral and phenol resins, ethylene /
Examples include an acrylic resin, an ethylene / vinyl acetate copolymer, rosin and derivatives thereof, and a terpene resin, and an ethylene / vinyl acetate copolymer is particularly preferable.

When the release layer is an elastomer + organic lubricant system, the elastomer / organic lubricant ratio is usually 5-95 / 95-
5 (weight), preferably 30 to 70/70 to 30 (weight). If the amount of the lubricant is 95% or more, the primary color image surface may slide too much, causing a risk of image misalignment when the secondary color is overprinted. More preferably, the rubber hardness of the elastomer alone is a rubber hardness meter (SHORE).
(A Type) is preferably 70 ° or less. When the release layer is an elastomer + organic lubricant + thermoplastic resin, the elastomer / organic lubricant / thermoplastic resin ratio is usually 5 to 40/90 to 30/5 to 30 (weight), preferably 30 to 40/60 to 50 / 10-20.

The thickness of the release layer is usually in the range of 0.2 to 5 μm, preferably 0.3 to 3 μm. The release layer can be formed by coating with a usual organic solvent solution (the solvent is toluene, methyl ethyl ketone, ethyl acetate, etc.) or a dispersion (the dispersion may be aqueous) or hot melt coating without using a solvent.

Next, the heat-meltable ink layer of the thermal transfer recording medium used in the present invention will be described. This heat-fusible ink layer is composed mainly of a colorant, an organic lubricant and a low-melting resin as in the prior art. In this case, the colorant is appropriately selected from conventionally known dyes and pigments. Specific examples of the organic lubricant include those similar to those in the release layer described above. As the low melting point resin, polyamide type, polyester type, polyurethane type, vinyl chloride type,
Examples of the resin include cellulose-based, petroleum-based, styrene-based, butyral-based, and phenol-based resins, as well as ethylene / vinyl acetate copolymers and ethylene / acrylic resins. The ratio of these components is as follows: colorant / organic lubricant / resins = 5 to 50
/ 30 to 90/5 to 50 (weight) is appropriate. As in the case of the release layer, the method of forming the hot-melt ink layer also employs an organic solvent solution or aqueous dispersion coating or hot melt coating. The thickness of the ink layer is usually in the range of 0.5 to 5 μm, preferably 1 to 3 μm.

Further, in addition to the above components, a fatty acid ester, a glycol ester,
Plasticizers such as phosphate ester and epoxidized linseed oil, and as softeners mineral oil, animal oil, vegetable oil, liquid paraffin,
A small amount (30% or less) of an oily substance such as silicone oil can be added. In the case of a release layer, a coloring agent can be added in a small amount.

Examples of the support for supporting the release layer and the heat-meltable ink layer include plastic films having good heat resistance, such as polyester, polycarbonate, triacetyl cellulose, polyamide, and polyimide, cellophane, sulfuric acid paper, and condenser paper. Can be used. If necessary, a heat-resistant layer such as a silicone resin, a fluorine resin, a polyimide resin, an epoxy resin, a phenol resin, a melamine resin, or a cellulose resin may be provided on one side of the support (the surface in contact with the thermal head).

In the present invention, the receiving paper can be appropriately selected from light-weight coated paper, art-coated paper, synthetic paper, film and the like according to the surface static friction coefficient.

[0023]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, all the parts shown below are based on weight.

Production Example 1 A mixture having the following composition was dispersed in a ball mill for 12 hours.
A release layer forming liquid [Solution A] was prepared. [Solution A] Polystyrene / polybutadiene / polystyrene block copolymer 3 parts Carnauba wax 7 parts MEK 90 parts

A mixture having the following composition was dispersed in a ball mill for 12 hours to prepare an ink layer forming liquid [liquid B]. [Solution B] Carbon black 3 parts Carnauba wax 10.5 parts Ethylene / vinyl acetate copolymer 1.5 parts Toluene 85 parts

First, the above-mentioned [Solution A] was applied to one surface of a 4.5 μm-thick polyester film (support) with a wire bar and dried to form a 1 μm-thick release layer. Next, the [liquid B] was applied on the release layer in the same manner,
After drying to form a heat-fusible ink layer having a thickness of 2.5 μm, a silicone resin is applied to the other surface of the support with a smoothing bar to form a heat-resistant layer having a thickness of 0.1 μm. 1 was created.

Production Example 2 A thermal transfer recording medium 2 was produced in the same manner as in Production Example 1, except that the formulation of the release layer forming liquid was changed to the following [Solution C]. [Liquid C] Unvulcanized ethylene propylene rubber 2 parts Ethylene / vinyl acetate copolymer 2 parts Carnauba wax 6 parts MEK 90 parts

Production Example 3 A thermal transfer recording medium 3 was prepared in the same manner as in Production Example 2, except that the formulation of the ink layer forming liquid was changed to the following [D liquid]. [Solution D] Yellow pigment 3 parts Carnauba wax 10.5 parts Ethylene / vinyl acetate copolymer 1.5 parts Toluene 85 parts

Production Example 4 A thermal transfer recording medium 4 was produced in the same manner as in Production Example 2, except that the formulation of the ink layer forming liquid was changed to the following [Solution E]. [E Solution] Magenta pigment 8 parts Carnauba wax 10.5 parts Ethylene / vinyl acetate copolymer 1.5 parts Toluene 85 parts

Production Example 5 A thermal transfer recording medium 5 was prepared in the same manner as in Production Example 1, except that the formulation of the release layer forming liquid was changed to the following [Solution F]. [F liquid] Butadiene rubber 2 parts Polyester resin 1 part Carnauba wax 7 parts MEK 90 parts

Production Example 6 A thermal transfer recording medium 6 was produced in the same manner as in Production Example 1 except that no release layer was provided.

Production Example 7 A thermal transfer recording medium 7 was produced in the same manner as in Production Example 1, except that the release layer was formed by hot melt coating of carbana wax and paraffin wax.

Examples 1 to 8 and Comparative Examples 1 to 8 Three types of receiving papers having the surface static friction coefficients shown in Table 1 below were prepared, and the receiving papers and the thermal transfer recording media obtained in the production examples were used. Using the combinations shown in Table 2, thermal transfer recording was performed, and the coefficient of friction, image breakage, and voids were evaluated. Table 2 shows the results.

[0034]

[Table 1]

[0035]

[Table 2] (Note) Judgment of friction coefficient ○: Difference is 0.3 or less; Image breaks ○: good, Δ: slightly poor, ×: poor cut. Void ○: None, △: Slightly observed, ×: Many observed.

[0036]

According to the first aspect of the present invention, there is provided a recording method for performing multi-color printing using a thermal transfer recording medium, wherein a surface of a primary color image on a side on which secondary color printing is performed and a surface of a receiving paper surface .
Since the difference between the static friction coefficient between the side of the surface printing is made is a configuration that performs printing of secondary color to the original combination of 0.3 or less, the receiving paper surface and the primary color images Since the difference in the static frictional resistance on the surface is small, it is possible to prevent misalignment in printing at the time of overprinting, and it is also effective for preventing transport wrinkles that occur when transporting the thermal transfer recording medium.

According to a second aspect of the present invention, there is provided a thermal transfer recording method, wherein the constituent material of the thermal transfer recording medium for forming the primary color image surface (that is, the constituent material of the release layer) is mainly composed of wax, thermoplastic resin and elastomer. Thus, the effect of improving the cut of the image is added.

According to a third aspect of the present invention, there is provided a thermal transfer recording method, wherein the thermoplastic resin comprises an ethylene / vinyl acetate copolymer and the elastomer comprises an unvulcanized rubber. The effect of reducing voids is added.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a method of the present invention.

FIG. 2 shows a configuration 1 of a thermal transfer recording medium used in the present invention.
It is a schematic cross section showing an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Receiving paper 2 Primary color image part 3 Secondary color image part 4, 5 Roller 6, 7 Thermal head 8, 9 Thermal transfer recording medium (ink ribbon) 11 Support material 12 Release layer 13 Thermal melting ink layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-289384 (JP, A) JP-A-4-219292 (JP, A) JP-A-6-79980 (JP, A) JP-A-6-79980 143846 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (3)

(57) [Claims] In a thermal transfer recording method for performing multi-color printing using a thermal transfer recording medium, secondary color printing on the surface of a primary color image is performed.
Thermal transfer recording the difference between the static friction coefficient between the surface and the side surface on which the print is made of receiving paper surface side to be made and characterized by applying printing the secondary color to the original combination of 0.3 or less Method. 2. The thermal transfer recording method according to claim 1, wherein the surface of the primary color image is mainly composed of a wax, a thermoplastic resin and an elastomer. 3. The thermal transfer recording method according to claim 2, wherein the thermoplastic resin is an ethylene / vinyl acetate copolymer, and the elastomer is an unvulcanized rubber.