JPH03180394A - Sublimation type thermal transfer recording sheet - Google Patents

Abstract

PURPOSE:To obtain a good thermal transfer image even on plain paper without lowering transfer density even when printing is performed many times by providing an ink layer region formed by laminating a dye supply layer wherein a sublimable dye is dispersed in an org. binder and a dye transfer contributing layer and a dye receiving substance supply layer region on a substrate. CONSTITUTION:A dye receiving substance supply layer region 7 containing a dye receiving substance is provided on a substrate 1 in parallel to an ink layer region 2. When an image is formed, at first, the dye receiving substance is transferred to a plain paper 3 from the dye receiving substance supply layer region 7 on a recording sheet and, thereafter, a sublimable dye is transferred to the part of the dye receiving substance transferred to the plain paper 3 from the ink layer region 2 to complete the formation of an image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sublimation type thermal transfer recording sheet, particularly to a sublimation type thermal transfer recording sheet for multiple printing.

[Prior Art] In recent years, the demand for full-color printers has increased year by year, and the recording methods for these full-color printers include electrophotography,
There are inkjet methods, thermal transfer methods, etc., but among these, the thermal recording transfer method is often used because it is easy to maintain and has no noise.

This thermal transfer consists of a fixed color ink sheet and an image-receiving paper, and images are formed by transferring the ink to the receiving paper by thermal melting or sublimation using thermal energy controlled by electrical signals from a laser or thermal head. This is a recording method that allows

This thermal transfer recording method can be roughly divided into the above-mentioned heat-melting transfer type and sublimation transfer type. In the latter, in principle, the sublimation dye is sublimated in a monomolecular form in response to thermal energy from a thermal head, etc. This method is considered to be the most suitable for full-color printers, as it has the advantage of easily obtaining intermediate tones and being able to control N tones at will.

However, this dye-sublimation transfer recording method uses a color ink sheet as a recording supply and selectively performs heating recording based on image signals. This method has the drawback that running costs are high because one ink sheet is used, and even if there is an unused portion, it is discarded.

Therefore, we are currently focusing on this drawback, and in an attempt to improve this drawback by using the ink sheet many times, we have developed a constant velocity mode method in which the ink sheet and image receptor are moved at a constant speed and used repeatedly, and the traveling speed of the ink sheet. An N-fold mode method has been proposed in which the overlapping portions of the first and second used portions of the coloring material layer are slightly shifted at a slower rate than that of the image receptor.

However, in the sublimation thermal transfer recording method, sublimation and evaporation reactions are basically zero-order reactions, and in constant velocity mode, even though the ink layer contains a sufficient amount of dye to withstand multiple uses, As the number of times of printing increases, the transfer density, especially in high image density areas, rapidly decreases, so there is a drawback that it is virtually impossible to print many times.

The reason why a thick conventional ink layer that uniformly contains a sufficient amount of dye to withstand multiple printings causes a sudden decrease in density after the second printing is because (1) the dye that contributes to transfer is concentrated on a small portion of the free surface of the ink layer; It was found that this is because (2) dye transfer follows Fick's law, and as a result, dye in the immediate vicinity of the free surface of the ink layer decreases with each printing.

Based on this knowledge, the present inventors injected dye from the dye supply layer into the lower layer of the dye transfer contributing layer in order to replenish the dye consumed in the upper layer (free surface layer) of the dye transfer contributing layer due to printing. In order to make it easier to compensate, we proposed designing each layer so that the relationship between dye supply layer and dye transfer contributing layer is high (see Japanese Patent Application No. 63-62866). Good results can be obtained when using special photographic paper on which a receptor layer is formed, but when thermal transfer is performed on plain paper, it is not always possible to obtain clear and good images.

[Problems to be Solved by the Invention] The present invention provides a dye-sublimation thermal transfer for multiple printing, which overcomes the drawbacks of the conventional technology, does not reduce the transfer density even after multiple printing, and provides a good thermal transfer image even on plain paper. The purpose is to provide a record sheet.

[Means for Solving the Problems] As a result of intensive research to achieve the above object, the present inventors have found that (1) a dye supply layer comprising a sublimable dye dispersed in an organic binder is provided on a substrate; The above objects can be achieved by providing a sublimation thermal transfer recording sheet provided with an ink layer region formed by laminating a layer contributing to dye transfer, and (2) a dye-receptive material supply layer region comprising a dye-receptive material. I found out.

The present invention is based on the invention disclosed in Japanese Patent Application No. 63-62866 filed by the present applicant. In a sublimation type thermal transfer medium in which dye transfer contribution layers are laminated, the dye supply layer and the dye transfer contribution layer are each formed as a single layer on the substrate with the same amount of adhesion in each formulation, and each of them is separately formed. A sublimation type thermal transfer medium characterized in that, when the image-receiving layer is overlapped with the image-receiving layer and the same thermal energy is applied to both, the amount of dye transferred to each image-receiving layer is in the following relationship: dye supply layer > dye transfer contributing layer. This invention is an improvement on the invention related to.

That is, in the present invention, a dye-receptive material containing a dye-receptive material is placed on the substrate in parallel with the ink layer region so that the dye can be thermally transferred well even onto plain paper that does not have a special ink-receiving layer. When forming a zero image characterized by providing a supply layer area, first, a dye-receptive substance is transferred onto plain paper from the dye-receptor substance supply layer area on the recording sheet, and then the Imaging is completed by transferring the sublimable dye from the ink layer area to the portion of the dye-receptive material transferred onto the plain paper.

Since the ink layer area on the recording sheet of the present invention is the same as the ink layer having a laminated structure of a dye supply layer and a dye transfer contributing layer in the above-mentioned application, the ink layer area will only be briefly described.

The thickness of the dye transfer contributing layer forming the ink layer region is generally 0.05 to 5 μm, preferably 0.1 to 2 μm.
The thickness of the dye supply layer is generally 0.1 to 2.
0 μm, preferably 0.5 to 5 μm.

Known sublimable dyes, binders, etc. can be used in the dye transfer contribution layer and the dye supply layer that form the ink layer region of the present invention.

A specific example of the sublimable dye used in the present invention is 60°C.
Any dye that sublimes or vaporizes and is mainly used in thermal transfer printing, such as disperse dyes or oil-soluble dyes, is acceptable.
．． 16.41, 54, 60.77, 116, etc., C11
, Dispersed thread 1.4, 6, 11, 15, 17
．． 55, 59, 60, 73.83, etc., C, 1, Disperse Blue 3.14.19.26.56, 60, 6
4.72, 99.108 etc., C11, Solvent Yellow 77.116 etc., C31, Solvent Red 23.25.27 etc., C, 1, Solvent Blue 3
6.83.105, etc., and as an anthraquinone or azo disperse dye, 5OT-B 1
u eG, 5OT-B lue 2.5OT-R
e d2G, 5OT-Red 200. S.

T-Red300.5OT-Red 800. S.O.
T-Yellow5.5OT-Ye 11 ow 5G
(all manufactured by Hodogaya Chemical Co., Ltd.), and these dyes can be used alone or in combination.

Thermoplastic or thermosetting resins are used as binders for the dye transfer contributing layer and the dye supplying layer, and examples of resins having relatively high glass transition points or high softening properties include, for example, vinyl chloride resins. , vinyl acetate resin, polyamide, polyethylene, polycarbonate, polystyrene, polypropylene, acrylic resin, phenolic resin, polyester, polyurethane, epoxy resin, silicone resin, fluororesin, butyral resin, melamine resin, natural rubber, synthetic rubber, polyvinyl alcohol, cellulose Examples include resin. These resins can be used alone, but several types may be mixed or a copolymer may be used.

Furthermore, when creating a difference in glass transition or softening temperature between the dye transfer contribution layer and the dye supply layer, resins or natural or synthetic rubbers with a glass transition temperature of 0°C or less or a softening temperature of 60°C or less are preferred, and specific Syndiotactic 1°2-polybutadiene (JSRR as a commercial product)
8810, 820, 830 (Japan Synthetic Rubber); Olefin copolymers and terpolymers containing acids or non-acidic acids (Dexon XEA-7, Dexon Gemical);
400A, 405, 430, Allied Fibers &
7 Las + Iasu; P-3307 (EVi50)
, P-2807 (EV250), Mitsui DuPont Polychemicals): Low molecular weight polyolefin polyols and their derivatives (commercially available products include Polytail H, HE Mitsubishi Chemical Industries); Brominated epoxy resin < YDB-340
, 400, 500, 600 Tobu Kagaku): Novolac type epoxy resin (YDCN-701, 702, 703 Tsukuto Kagaku): Thermoplastic acrylic trusion (Titanal L
R1075, 1080°1081, 1082.1063
．． 1079 Mitsubishi Rayon); Thermoplastic acrylic emulsion: l:/ (LX-400, LX-450, Mitsubishi Rayon); Polyethylene oxide (Alcox E-3
0,45, Alcox R-150,400,1000
Meisei Chemical Industries); caprolactone polyol (Plaxel H1, 4, 7, Daicel Chemical Industries) and the like are preferred;
In particular, polyethylene oxide and polycaprolactone polyol are practically useful, and it is preferable to use them in a mixed form with one or more of the above-mentioned thermoplastic or thermosetting resins.

The dye content of the dye transfer contributing layer is usually 5 to 80%, preferably about 10 to 60X.

In addition, the dye content of the dye supply layer is 5 to 80%.
However, when creating a dye concentration gradient between the dye transfer contribution layer and the dye supply layer, the dye content is preferably 1.1 to 5 times, preferably 1.5 to 5 times, the dye concentration of the transfer contribution layer. 3
@ is preferable.

The dye-receptive material supply layer region containing the dye-receptive material is made of a material that can be easily transferred by thermal printing with a thermal head, pressure, or heat pressure and has a relatively low melting point.
Examples include polyester with a low melting point, vinyl chloride, vinyl acetate, and acrylic resins, preferably those with a melting point of 110°C or lower. The thickness of the supply layer is 1 to 50 μm, preferably 3 to 20 μm.

If necessary, a release layer of silicone-based or Teflon-based binder wax may be provided in advance before applying the binder onto the base sheet.

In addition, recording using an ink layer is likely to cause peeling or fusion of the ink layer at the interface between the ink layer and the receiving layer due to shifting recording due to speed differences, which can easily cause running defects. It is also possible to contain a known substance having lubricity or mold release properties, or, if necessary, to use a heat-resistant resin or a resin that is cured by adding a curing agent.

Examples of substances having lubricity or mold release properties (lubricity substances) include petroleum-based lubricating oils such as liquid paraffin, synthetic lubricating oils such as hydrogen halides, diester oils, silicone oils, and fluorosilicone oils, and various modified lubricating oils. Silicone oils (epoxy-modified, amino-modified, alkyl-modified, polyether-modified, etc.), silicone-based lubricating substances made of copolymers of silicone and organic compounds such as polyoxyalkylene glycol, various fluorine-based surfactants such as fluoroalkyl compounds, Fluorine-based lubricating substances such as trifluorochloroethylene low polymers, paraffin wax, polyethylene waxes,
Examples include higher fatty acids, higher aliphatic alcohols, higher fatty acid amides, higher fatty acid esters, higher fatty acid salts, and the various particles mentioned above as particles having lubricity or thermal release properties.

Films such as condenser paper polyester film, polystyrene film, polysulfone film, polyimide film, polyamide film, etc. are used as the base sheet, and a conventional adhesive layer or the like is provided between the base sheet and the dye supply layer as necessary. Also,
A conventional heat-resistant lubricant layer may be provided on the back surface of the base sheet, if necessary.

Although the above description has been made with reference to a recording method using a thermal head, the transfer medium of the present invention can also be applied to a recording method in which recording thermal energy is applied by a method other than a thermal head, for example.
It can also be used for methods using Joule heat generated in a medium such as a thermal printing plate, laser light, or a support.

Among these, the so-called electric thermal transfer method, which uses Joule heat generated in the medium, is the most well-known.
, 103,066, JP-A-57-14060, JP-A-5
It is described in many documents such as 7-11080 and JP-A-59-9096.

When used in this current transfer method, resins with relatively low melting points such as polyester, polycarbonate, triacetyl cellulose, nylon, polyimide, aromatic polyamide, etc. are used as a support, and aluminum, copper, iron, tin, zinc, nickel, Supports in which metal powders such as molybdenum and silver and/or conductive powders such as carbon black are dispersed to adjust the resistance to a value between that of an insulator and a good conductor, and conductive metals such as those described above are used in these supports. The thickness of these supports is desirably about 2 to 15 microns in consideration of the Joule heat conduction efficiency.

In addition, when using the laser beam transfer method, it is sufficient to select a material that absorbs laser light and generates heat as a support. For example, a conventional thermal transfer film may contain a light absorption conversion material such as carbon, or A material in which layers are formed on the front and back surfaces of a support is used.

EXAMPLES Hereinafter, the present invention will be explained in more detail based on the following examples, but the present invention is not limited thereto.

Example 1 [Formation of dye-receiving substance supply layer region] Part by weight Low melting point polyester resin XA-7052 (manufactured by Unitika ■ Contact point 8
6°C) 30 Silicone oil 5F8417 3 (manufactured by Toray Silicone) Dispersant 2 Solvent Methyl ethyl ketone 60 Toluene
60 The above formulation was sufficiently dispersed to prepare a coating agent for supplying a dye-receptive substance.

As shown in FIGS. 2 and 3, the composition of the above formulation is applied to an aromatic polyamide material having a thickness of approximately 6.5 μm and a width of 210111, with a silicone-based lubricating and ripening-resistant layer approximately 0.5 μm thick on the back side. It was coated onto a film substrate (manufactured by Toshi) 1 using a wire bar and dried at 100° C. for 1 minute to form a dye-receptive material supply layer region 7 having a thickness of about 5 μm.

[Formation of ink layer region] Parts by weight Polyvinyl butyral resin 6χ-110 (manufactured by Tansui Kagaku Kogyo) Sublimable dye Kayaset Blue 14 (manufactured by Nippon Kayaku) Solvent Toluene 100 Methyl ethyl ketone 100 In the above formulation, for the dye supply layer In the formulation, the above sublimable dye is 20 parts by weight, and in the dye transfer contributing layer phase formulation, the above sublimable dye is 10 parts by weight, and silicone oil 5F8 is added.
417 (manufactured by Toray Silicone) was added, and each composition was dispersed in a ball mill for 24 hours. Thereafter, 1.5 parts by weight of Coronate L (manufactured by Nippon Polyurethane Co., Ltd.) was added to the supply layer formulation and thoroughly stirred.

Next, a sublimation type thermal transfer recording sheet S of S structure as shown in FIG. 1 was prepared as follows.

As mentioned above, as shown in FIG. 2, the dye supply layer 4 is placed in parallel with the dye-receptive substance supply layer region 7 formed on the aromatic polyamide film substrate (manufactured by Toshi) 1 using a wire bar. After applying the ink composition to a film thickness of 3.0 μm, a dye transfer contributing layer 5 having the above formulation is further applied thereon.
The ink composition was applied to a film thickness of 0.8 μm to form the ink layer region 2, and the ink composition was applied to the sublimation thermal transfer recording sheet S.
was manufactured.

[Printing Recording Experiment] First, using a sublimation thermal transfer recording sheet S and plain paper 3 in which the dye-receptive substance supply layer region 7 and the ink layer region 2 are arranged in parallel, the dye-receptive substance supply layer region 7 is The thermal head 6 records a recording density of 6 dots from the back of the sheet.
A solid thermal transfer of the dye-receptive material was carried out on plain paper 3 under printing conditions of -2 applied energy t and 60 IIJ/dot. As a result, a glossy dye-receiving layer made of resin was formed all over the plain paper.

Next, a pressure 442 is applied from the back surface of the sublimable ink layer region 2 adjacent to the dye-receiving layer transferred solidly onto the plain paper 3.
Density steps of 16 gradations were printed and recorded under printing conditions of nW/dot, maximum applied energy of 2.21 αJ/dot, and speed ratio of image receiving sheet (?sheet passing) to recording sheet n=5. As a result, a good cyan image with 16 gradations was formed on the dye-receiving layer formed on the plain paper as shown in FIG. 4.

Example 2 [Formation of dye-receiving substance supply layer region] A dye-receiving substance supply layer region was formed in exactly the same manner as in Example 1.

[Shape e of ink layer region] Regarding the cyan ink layer region 2C, the ink layer region was formed in exactly the same manner as in Example 1.

Next, for the magenta color ink layer region 2M, H5Re is used instead of the cyan color Kayaset Blue 14.
d G (manufactured by Mitsui Toatsu) and Hacrolex Red
An ink layer region was formed in the same manner as in Example 1 except that a dye mixed with Violet R (manufactured by Bayer) at a mixing ratio of 2=1 was used.

Furthermore, for the yellow ink layer region 2Y, Hacr
The ink layer region was formed in the same manner as in Example 1 except that Olex Yellow 6G (manufactured by Bayer) was used. (Fig. 3) [Print recording experiment] As in Example 1, a dye-receiving layer was first transferred onto plain paper, and then as in Example 1, a color image pattern was printed in the order of yellow, magenta, and cyan. When recording, an image was formed under the printing conditions of a speed ratio of n-5, and a good color image was formed with almost no decrease in density.

[Effects of the Invention] As described above, by using a sublimation type transfer recording sheet as in the present invention, it is possible to perform multiple recordings without causing a rapid decrease in transfer density even when the speed difference mode increases by a factor of n. It is possible to obtain clear images even on plain paper.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are explanatory views showing the structure of the sublimation type thermal transfer recording sheet of the present invention. FIG. 4 is a graph showing the multiple printing characteristics of the sublimation type thermal transfer recording sheet of Example 1. DESCRIPTION OF SYMBOLS 1...Support 2...Ink layer area 3...Plain paper 4...Dye supply layer 5...Dye transfer contributing layer 6...Thermal head 7...Dye receiving material supply layer Area 2Y...Yellow sublimable ink layer area 2M...Magenta sublimable ink layer area 2C...Cyan sublimable ink layer area S...Thermal transfer recording sheet

Claims (1)

[Claims] On the substrate, (1) an ink layer region formed by laminating a dye supply layer and a dye contribution layer formed by dispersing a sublimable dye in an organic binder; and (2) a dye receiving layer formed of at least a dye receiving substance. A sublimation type thermal transfer recording sheet provided with a sexual substance supply layer area.