JP2609979B2 - Image recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention operates a thermal head based on an electric signal controlled by a video signal or the like, heats the thermal transfer sheet from the back side, and sublimates the dye in the thermal transfer sheet on the thermal transfer sheet. By doing
The present invention relates to an image recording method suitable for obtaining a multicolor overprinted recording.

[0002]

2. Description of the Related Art As a heat transfer sheet to be used in combination with a heat transfer sheet, a dye-dyeable resin such as a thermoplastic polyester resin is formed into a paint on a base material such as paper.
Although dried ones are used, as can be seen from this conventional example, not all papers and plastic films can be used as heat transfer sheets, but dye dyeing properties (coloring properties), weather resistance, and What was created in consideration of the storability of the product is used.

[0003] However, even by analogy with the above-mentioned conventional examples and the usual method of image formation, the heat transfer sheet is usually an apparently simple white sheet, and various resins,
Even if the paint prepared by adding additives as needed is applied in one or more layers, it is difficult to distinguish it with the naked eye, and paper for other recording methods, for example, electrostatic copying paper or heat-sensitive paper Needless to distinguish from recording paper, etc., even with the same method, there is a great need to distinguish from several types of thermal transfer sheets depending on compatibility with a recording apparatus or a thermal transfer sheet or use.

[0004]

However, conventionally,
Once the package has been unpacked, this type of heat transfer sheet is difficult to distinguish from the appearance, and no means for distinction has been taken.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide means for distinguishing various heat transfer sheets or a heat transfer sheet from a sheet for another recording system.

[0006]

The image recording method of the present invention comprises a heat transfer sheet having a heat transfer layer containing a sublimable dye on a substrate, and a receiving layer on which a dye sublimating from the heat transfer sheet is dyed. A heat transfer sheet provided on the front surface of a flexible sheet substrate and provided with an optically detectable detection mark on the back surface is transported so that the heat transfer layer and the receiving layer overlap each other, and provided in the printer. Before being conveyed to a certain position of the thermal transfer sheet, the detection mark provided on the heat transfer sheet was detected from the back surface of the heat transfer sheet by an optical sensor provided in the printer, and whether or not the transfer was possible was confirmed. Thereafter, heat recording is performed by a thermal head.

FIGS. 1 to 3 show a typical embodiment of the present invention. The heat transfer sheet 1 shown in FIG.
A surface of the substrate 2 on which the receiving layer (described later) is not provided;
That is, the heat transfer sheet 1 shown in FIG. 2 is a mark which can be optically detected on the entire back surface of the base material 2. The heat transfer sheet 1 shown in FIG. 3 has a symbol 5 which is an optically detectable mark at a corner on the back surface of the substrate 2. is there.
As can be understood from the above examples, the optically detectable marks of the heat transfer target sheet 1 may be made of various materials or have various shapes. In addition to the above, for example, a detection mark may be provided in which a part of the base material is provided with irregularities to partially change the light reflectance.

The detection mark as described above may be in the form of a line, stripe, matrix, character, or pattern, or a combination of the above shapes. The pattern may be a circle, an ellipse, a triangle, a rectangle, a trademark (including characters), or the like. Various positions can be considered as positions where these marks are provided. However, since the receiving layer is to form an image, it is provided on the side of the substrate where the receiving layer is not provided, that is, on the back side.

Further, there are various possible arrangements of the marks. If it is a line or a stripe, it will generally be provided at or near the edge of the thermal transfer sheet and parallel to the edge. However, it may be provided at the center of the heat transfer sheet, or may be provided obliquely, not parallel to the edge. In the case other than lines and stripes, it is generally provided at a corner, but it may be provided on one surface or at the center. Further, the number of marks may be plural instead of one, and two or more marks having different patterns may be provided.

On the surface of the heat transfer sheet, there is provided a receiving layer for transferring and dyeing a sublimable dye on a substrate. The thickness of the receiving layer provided on the substrate 2 is usually 3 to 50 μm.
, And can be of any thickness depending on the application.
As the substrate, plain paper, various synthetic papers, and flexible thin sheets such as plastic films can be used. This base material has a role of holding the receiving layer, and since heat is applied at the time of thermal transfer, it is desirable that the base material has a mechanical strength that does not hinder handling even in a heated state.

[0011] As described above, the receiving layer of the heat transfer sheet has a function of receiving and dyeing the dye transferred from the heat transfer sheet when heated. Synthetic resin is used. (A) Those having an ester bond: polyester resin, polyacrylate resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, vinyl toluene acrylate resin, and the like. (B) Those having a urethane bond Polyurethane resin and the like. (C) Those having an amide bond. Polyamide resin etc. (D) Those having a urea bond, such as a urea resin. (E) Others having a highly polar bond Polycaprolactone resin, styrene-maleic anhydride resin, polyvinyl chloride resin, polyacrylonitrile resin and the like. In addition to the above synthetic resins, mixtures or copolymers thereof can also be used.

The receiving layer may be formed of two kinds of resins having different properties. For example, -100 to 20
The first region of the receiving layer is formed of a synthetic resin having a glass transition temperature of about 90 ° C. and having a polar group.
The second region of the receiving layer can be formed of a synthetic resin having a glass transition temperature of not less than ° C. The first region and the second region are both exposed on the surface of the receiving layer, the first region occupies 15% or more of the surface, and the first regions exist independently of each other in an island shape. The length in the longitudinal direction of each of the shape portions is preferably 0.5 to 200 μm.

An inorganic filler such as finely divided silica or a release agent may be added to the receiving layer. Here, silica refers to silicon dioxide or a substance containing silicon dioxide as a main component.
The fine powder silica to be contained in the receiving layer has an average particle diameter of 10 to 100 mμ and a specific surface area of less than 250 m ² / g, and more preferably has an average particle diameter of 10 to 50 mμ and a specific surface area of 20 to ²⁰⁰ m ² / g. Is used.

When the average particle size of the finely divided silica is larger than this range, the dispersion stability of the finely divided silica in the coating composition for the heat transfer layer used for forming the receiving layer is reduced, and the surface of the receiving layer of the heat transfer sheet is deteriorated. The smoothness is significantly impaired, and the image obtained by thermal transfer becomes unclear. When the average particle diameter of the finely divided silica is smaller than this range, the fluidity of the coating composition for the heat transfer layer used for forming the receiving layer is reduced, and the effect of adding the fine powder silica to the heat transfer sheet is sufficiently exhibited. Not done.

Specific examples of the finely divided silica satisfying the above conditions include AEROSILR972 and AEROS
IL 130, AEROSIL 200, AEROSI
LOX50, AEROSIL TT600, AERO
SIL MOX80, AEROSIL MOX170
(Silica powder manufactured by Aerosil Co., Ltd.). The content of the finely divided silica is in the range of 5 to 20% by weight, more preferably 5 to 10% by weight, based on the weight of the receiving layer. These fine silica powders are previously added to the resin forming the receiving layer, and are applied as a resin solution on the substrate.

The release agent is used for the purpose of enhancing the releasability from the thermal transfer sheet, and is a cured product of a silicone compound, for example,
Examples include a cured product of an epoxy-modified silicone oil and an amino-modified silicone oil.

The above-mentioned heat transfer sheet of the present invention is superimposed on a heat transfer sheet containing a dye (for example, a disperse dye or a sublimable dye) which is transferred by heat in a heat transfer layer, and is usually placed on a thermal head or the like from the heat transfer sheet side. Heating and recording using the shape heating means, but at a position of the point heating means, a sensor according to the type of mark in advance before being conveyed, for example,
The presence of the mark and, if necessary, the information recorded on the mark are read by an optical sensor to check whether or not the mark can be transported.

[0018]

Example 1 A coating for a receiving layer having the following composition was applied to a smooth surface of a cast coated paper having a thickness of 95 g / m ² to a thickness of 8 μm after drying and dried to form a receiving layer. After formation, letters were printed on the back using gray gravure ink. Coating composition for receiving layer Polyester resin (manufactured by Toyobo, Byron 200) 10 parts by weight Amino-modified silicone (manufactured by Shin-Etsu Silicone, KF-393) 0.3 part by weight Epoxy-modified silicone (manufactured by Shin-Etsu Silicone, X-22-343) 3 parts by weight This was dissolved in 90 parts by weight of a mixed solution of methyl ethyl ketone / toluene / cyclohexanone = 4/4/2 to prepare a coating.

The heat transfer sheet obtained above is detected by providing a reflection type photosensor at the entrance of the thermal transfer printer, and after confirming that the sheet is an appropriate heat transfer sheet,
Run to a thermal transfer printer, contact the dye layer (formed by applying and drying a paint of the following composition) of a 9 μm thick PET film-based transfer film installed inside the printer and the receiving layer surface, and from the back of the transfer film The image was heated by a thermal head to form a transferred image. Dye layer composition Basic dye (manufactured by Hodogaya Chemical, TH1109) 5 parts by weight Polyvinyl butyral resin (manufactured by Sekisui Chemical, Esrec BX-1) 4.5 parts by weight 90 parts by weight of a mixed solvent of toluene / methyl ethyl ketone = 1/1 Was dried and applied (1.5 g / m ^{2 by} dry weight).

Example 2 A toluene / methyl ethyl ketone mixed solution (solid content: 10%) of a polyurethane elastomer (manufactured by Dainippon Ink, Pandex T5670) was dried on a smooth surface of a cast coated paper having a surface area of 110 g / m ² and dried. 2 g / m ^{2 in} weight
After coating and drying, the same receiving layer as in Example 1 was coated and dried so as to have a thickness of 5 μm after drying, and then a fluorescent dye was solid-printed on the back surface and transferred by heat. I got a sheet. This heat transfer sheet is detected by a reflection type photosensor provided at the entrance of the thermal transfer printer, and after confirming that the sheet is an appropriate heat transfer sheet, the sheet is moved to the heat transfer printer, and the transferred image is transferred in the same manner as in Example 1. Was formed.

[0021]

According to the image recording method of the present invention, in addition to the structure for receiving an image, recording is performed using a heat transfer sheet having a mark detectable by an optical sensor on the back surface of the substrate. Therefore, it is possible to select a heat transfer sheet suitable for the apparatus and perform recording without any problem.
For example, in the image formation by the sublimation transfer method, the thermal transfer sheet and the thermal head are linked via the detection mark, so that the thermal head operates in a state where the thermal transfer sheet does not exist, heats the thermal transfer sheet, and the dye is thermally transferred. The sheet is transferred to a platen roll that does not exist,
The effect of so-called blanking does not occur at all, such as contamination of the platen roll and contamination of the back surface of the heat transfer sheet by the contaminated platen roll.

[Brief description of the drawings]

FIG. 1 is a bottom view of a heat transfer sheet of the present invention.

FIG. 2 is a bottom view of the heat transfer sheet of the present invention.

FIG. 3 is a bottom view of the heat transfer sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat transfer sheet 2 Base material 3 Character 4 Fluorescent ink layer 5 Symbol

Claims (1)

(57) [Claims] 1. A heat transfer sheet having a heat transfer layer containing a sublimable dye on a base material, and a receptor layer on which a dye sublimated from the heat transfer sheet is dyed is provided on the surface of a flexible sheet base material; A heat transfer sheet provided with an optically detectable detection mark on the back side is transported so that the thermal transfer layer and the receiving layer overlap, and before being transported to a position of a thermal head provided in the printer. The detection mark provided on the heat transfer sheet from the back surface of the heat transfer sheet,
An image recording method, comprising detecting with an optical sensor provided in a printer, confirming whether or not conveyance is possible, and then performing heating recording with a thermal head.