JP2003211834A - Composite recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite recording material with which both a high speed printing of a monochrome and a simple plural colors and a printing with a silver salt photographic image quality coexist with each other and printing can be inexpensively performed. <P>SOLUTION: A base sheet 2 such as a paper is provided and one face of the base sheet 2 is thinly coated with a heat sensitizer 3 developing a color by exposure to light or heating and a heat-sensitive color developing layer 4 exists on one face like a heat-sensitive paper. A transparent ink absorbing layer 5 is formed on the heat-sensitive color developing layer 4. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

The present invention is applied to a print recording medium of an image forming apparatus of information equipment.

[0002]

2. Description of the Related Art Looking at conventional techniques by printing method, on the other hand, in direct thermal method printing in which the recording material is colored by the amount of heat transferred to the recording material such as thermal paper, when performing multicolor printing, The amount of heat transferred to the recording material was adjusted by a thermal head, and multicolor printing was realized by adjusting the degree of color development of a color-developing substance that differs in color depending on the amount of heat. Moreover, in the direct thermal type printer specialized in multicolor printing which is being developed in recent years, it is necessary to print three primary colors.
This is achieved by a complicated process in which heat is generated in two separate steps to develop color, and two of these are exposed to UV light to be fixed.

On the other hand, in the ink jet system for directly applying a plurality of colors of ink to a recording material, a plurality of ink nozzles are provided and a small amount of the ink is ejected from the ink nozzles, and at the same time, an ink head which is an assembly of the ink nozzles. To
By moving the recording material or moving the recording material with respect to the ink head, the ink is applied to the recording material to perform multicolor printing.

Due to the structure of the two systems, the main advantage of the direct thermal system is high-speed printing with a single color or a simple multi-color, and the main drawback is that the high-speed printing has many problems with the silver salt photographic image quality similar to the inkjet system. High-speed printing of colors is difficult. On the contrary, the main advantage of the inkjet method is that it is easy to perform multicolor printing with silver halide photographic quality, and the main drawback is that it is simpler than single color and simple multicolor printing. The printing speed is slow.

Regarding the printing by the sublimation type thermal transfer method other than the above-mentioned two printing method, although the printing of silver salt photographic image quality is possible, the printing speed is slower than that of the direct thermal method when printing with a single color and a simple plural colors, Since an ink ribbon is required in addition to producing a large amount of industrial waste, the cost of the device and the printing running cost are high.

[0006]

In multicolor printing, printing of "three primary colors" of magenta, yellow, and cyan is essential. On the other hand, in the direct thermal printing method,
In order to print the three primary colors of color and to express fine gradations of the three primary colors, it is necessary to control complicated heat generation in the thermal head, and it is difficult to control each fine dot such as 1440 dots per inch. It was Therefore, the image printed by the direct thermal method is inferior in image quality as compared with the ink jet method capable of printing like a silver salt photograph. However, since the thermal heads arranged in a line print each line, the printing speed in monochromatic printing and simple multi-color printing is significantly higher than that of the inkjet method. Further, in a direct thermal printer specialized for multicolor printing, a complicated process of printing heat in three primary colors to generate heat, and exposing two times to ultraviolet rays to fix the color is complicated. Not only multicolor printing but also single-color and simple multi-color printing requires significantly longer printing time than the inkjet method.

On the other hand, in the ink jet system, 1
Although it is easy to control each fine dot such as 1440 dots per inch, since the ink head, which is an assembly of ink nozzles, is moved relative to the recording material and a plurality of colors of ink are applied to the recording material, Compared to the direct thermal method, it is possible to print faster in multicolor printing, in which the three primary colors are printed with subtle gradations, but in single-color and simple multiple-color printing, one line can be printed simultaneously. It took longer to print than the printing method.

In order to obtain high-speed printing, photographic image quality, and low printing cost, which are the advantages of the above-mentioned two methods, when ink is simply printed on a recording material such as thermal paper by the ink jet method, the ink is on the surface of the recording material. It didn't fix instantly, and it took more than a few minutes for it to dry and stabilize, which made it unusable in actual use.

Further, even if a void is simply formed on a recording material such as thermal paper as an absorption layer of an ink jet, the heat of the thermal head is not transmitted to the thermosensitive coloring layer due to the void, so that coloring is difficult and printing is difficult. It was

Therefore, it is very difficult to make good use of these two methods, that is, to achieve high-speed printing of single color and simple multi-color at low cost and printing of silver salt photographic quality.

The present invention has been made to solve such a conventional problem, and an object thereof is to achieve both high-speed printing of single color and simple multiple colors and printing of silver salt photographic quality. It is to provide a recording material that can be printed at low cost.

[0012]

In order to achieve the above object, the invention according to claim 1 has a base sheet, and a heat-sensitive agent that develops a color by exposure or heating is applied to one surface of the base sheet. It is characterized in that it has a thermosensitive coloring layer and has a transparent ink absorbing layer on the thermosensitive coloring layer.

In the invention according to claim 1, for example, a heating body such as a thermal head which has generated heat is brought into contact with the heat-sensitive color forming layer, so that a colorless dye such as a leuco dye which is solid at room temperature provided in the heat-sensitive color forming layer and a phenol type A color developer such as an acidic substance is melted, and both are brought into contact with each other to obtain a color image. Since the color is heated by the thermal heads arranged in a row to develop the color, the color image can be obtained at an extremely high speed. Therefore, simple color and simple multi-color character printing, and a simple shape or contrast such as a barcode are required. Used for printing images. On the other hand, the ink ejected from the inkjet nozzle is extremely finely ejected to the ink absorption layer at 1440 dots per inch and 4 picoliters, and by the combination of the three primary colors of yellow, magenta, and cyan, and black, A multicolor image can be obtained. Examples of the thermosensitive coloring layer include colorless dyes such as leuco dyes and color developers such as phenolic acidic substances.
Not limited to this, any substance used in so-called thermal paper and having a thermosensitive coloring effect can be used. An ink absorbing layer having high transparency is formed on the thermosensitive coloring layer.

According to the second aspect of the present invention, a thermosensitive coloring layer is formed from the ink absorbing layer by forming a layer (water resistant layer) between which the liquid hardly penetrates between the thermosensitive coloring layer and the ink absorbing layer. It is effective in preventing ink from penetrating into the layer and carelessly developing the color of the thermosensitive coloring layer due to water contained in the ink or an organic solvent such as alcohol.

According to the third aspect of the invention, by suppressing the porosity of the ink absorbing layer to 10% or less, the heat of the heating element such as the thermal head is transferred to the heat-sensitive color developing layer with little loss, and the heat-sensitive color developing layer is formed. It is effective for keeping high coloring efficiency.

According to the invention described in claim 4, the transmittance is 5
By forming the ink absorbing layer to 0% or more, the color image of the thermosensitive color developing layer is transmitted, and it is effective to obtain a clear thermal printing image with high contrast.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a composite recording material according to the present invention will be described in detail with reference to the drawings. Figure 1
FIG. 2 shows an embodiment of the composite recording material of the present invention.
FIG. 1 is a cross-sectional view of the composite recording material of the present invention, and FIG. 2 is a schematic view of printing on the composite recording material of the present invention by a direct thermal method.

As shown in FIG. 1, the composite recording material 1 of the present embodiment has a base sheet 2 such as paper, and a heat sensitive agent 3 which develops a color by exposure or heating is provided on one surface of the base sheet 2. It is thinly coated and has a thermosensitive coloring layer 4 on one surface like thermal paper. A transparent ink absorbing layer 5 is formed on the thermosensitive coloring layer 4.

The base sheet 2 may be paper, cloth, or a thin sheet of synthetic resin such as polyethylene terephthalate, and the color is a white system color, which is basically about 80% of the whiteness of Japanese Industrial Standard, but it is a design. It is also possible to use a base sheet that is colored for some reason. The thickness is preferably 60 μm to 90 μm, which is similar to that of a general-purpose thermal paper from the viewpoint of availability, but is not particularly limited as long as the required function can be obtained.
These substrates may be subjected to corona discharge treatment or undercoat for the purpose of improving the adhesive strength of the heat sensitive layer.

The heat-sensitive agent 3 is not limited to the above-mentioned colorless dye such as a leuco dye and a color-developing agent such as a phenolic acidic substance as long as a required function can be obtained, and is used in a commercially available heat-sensitive paper. Most of the things can be used.

The ink absorbing layer 5 is preferably transparent and has a linear transmittance of 50% or more. Further, in consideration of color development efficiency by heat, it is preferable that the ink absorbing layer have a porosity as small as possible. Specifically, the porosity R defined in "JAPAN TAPPI paper pulp test method paper-pore amount distribution test method by mercury porosimetry" is preferably 10% or less. In view of these, as the ink absorbing layer, for example, a transparent ink absorbing layer having a small porosity as disclosed in JP-A-62-146674 and JP-A-9-039372 can be adopted.

The ink absorbing layer may be a single layer or multiple layers.
Considering the color development efficiency of the heat-sensitive layer, the thickness of the ink absorbing layer is 2-20 μm, preferably 3-10 μm. When it is less than 2 μm, the risk that the ink overflows to the heat sensitive layer side increases. Therefore, it is preferable to increase the film thickness of the ink absorbing layer to increase the ink receiving amount, but when the film thickness becomes 0 μm or more, the heat sensitive layer It is important to determine the optimum film thickness in consideration of the balance between the two, because the color development efficiency gradually decreases and it becomes difficult to develop color at 20 μm or more.

Further, it is preferable to form a layer (water resistant layer) which is difficult for liquid to permeate between the thermosensitive coloring layer and the ink absorbing layer. When the film thickness of the ink absorption layer is relatively large, it is not necessary to form it because the ink does not penetrate to the thermosensitive coloring layer. However, when the film thickness of the ink absorption layer is relatively small, the ink absorption layer Since the ink penetrates from the layer into the thermosensitive coloring layer and the organic solvent such as water and alcohol contained in the ink causes the thermosensitive coloring layer to color carelessly, it is preferable to provide a water resistant layer. As the water resistant layer, the same material as that generally used as an overcoat of thermal paper can be adopted. For example,
A structure in which a material containing a water resistant material is used as the overcoat layer is disclosed in Japanese Patent Laid-Open No. 61-69489.
No. 61-139482, No. 62-32081, No. 62-32081
No. 62-42882, etc., but those disclosed therein can be used as the water resistant layer of the composite recording material of the present invention.

The polymer in the ink absorbing layer may be transparent as long as it has a function of absorbing ink. For example, Polymer Complex (Japanese Patent S51-37
017), albumin, gelatin, casein, starch,
One or more of cationic starch, gum arabic, polyvinyl alcohol, SBR latex, polyvinylpyrrolidone, carboxymethyl cellulose, aqueous polyester and the like may be used in combination.

Further, in order to improve the image density, water resistance and bleeding resistance recorded by the ink jet system, a compound having a cationic property having a function of fixing a dye in the ink absorbing layer may be added.

Further, fillers and other additives may be used in combination within the range not impairing the achievement of the object of the present invention. Examples of the filler include inorganic fine particles such as silica / alumina and organic fine particles such as polystyrene, polyethylene and polyacrylate. As the additives, various kinds of surfactants, water resistant agents, defoaming agents, ultraviolet absorbers, dispersants, cross-linking agents, anti-fading agents, pH adjusting agents and the like can be mentioned.

As a method for forming the ink absorbing layer on the heat-sensitive layer, the above-mentioned materials are dissolved or dispersed in a suitable solvent to prepare a coating solution, for example, a roll coater, an air knife coater, a blade coater, a rod coater, A method of coating on the heat-sensitive layer by a known method such as a bar coater, a comma coater, a die coater, and then quickly drying is preferable.

As shown in FIG. 2, when the heating body 11 such as a thermal head that has generated heat contacts the thermosensitive coloring layer 4,
A colorless dye 12 such as a leuco dye and a developer 13 such as a phenolic acidic substance which are solid at room temperature provided in the thermosensitive coloring layer 4 melt and the colorless dye 12 and the developer 13 come into contact with each other to form a coloring portion. You get 14. A color image is obtained by combining the color portions 14.

(Examples) The present invention will be described in detail below with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples. Substrate and thermosensitive coloring layer: commercially available thermal paper (TF50KS
-E Nippon Paper Industries Co., Ltd.) was used. The heat-sensitive agent of the heat-sensitive layer of the heat-sensitive paper is provided with a colorless dye such as a leuco dye and a color developer such as a phenolic acidic substance.

Example 1 The following coating liquid was applied onto the thermal paper to obtain an ink absorbing layer. A coating solution containing 10 parts of polyvinyl alcohol (PVA-117 manufactured by Kuraray Co., Ltd.) and 90 parts of water was applied by an air knife coater and dried to obtain a layer having a thickness of 2 μm. The following coating liquid was applied to this layer. Polyvinylpyrrolidone (GAF, PVPK-90) 10% aqueous solution
70 parts Isobutylene maleic anhydride copolymer (Kuraray Isoprene, Isopan 10) 10% DMF solution A coating solution containing 30 parts was applied by an air knife coater and dried to obtain a layer having a thickness of 6 μm. The following coating liquid was further applied to this layer. A coating solution containing 13 parts of cation-modified PVA (PVA-C-418A manufactured by Kuraray Co., Ltd., PVA-C-418A), 2 parts of differential silica and 85 parts of water was applied by an air knife coater and dried to obtain a layer having a thickness of 1 μm.

Example 2 The following coating liquid was applied onto the heat sensitive layer to obtain an ink absorbing layer. Polyvinyl alcohol (PVA-217) 8 parts Cation-modified PVA (Kuraray, PVA-C-418A) 2 parts Water A coating solution containing 90 parts was coated with an air knife coater and dried to obtain a layer with a thickness of 9 μm. It was

Comparative Example 1 Only thermal paper.

[0033]

According to the present invention, it is possible to easily print on a thermal paper, which has been difficult in the past, by an ink jet method.

That is, in addition to high-speed printing of single-color and simple multi-color printing on the same surface of the recording material, it is possible to easily realize printing of the image quality on the silver salt photographic image level.

An actual example will be described in view of issuance of a receipt at a sales store. On the other hand, since printing can be performed in a short time by issuing a receipt in the direct thermal printing, it is possible to shorten the time that the customer waits at the time of checkout at a sales store or the like. In addition, it is possible to easily and quickly print barcodes, 2D symbols, and the like that require precision and accuracy. Bar code or 2
The D symbol is effective for return processing.

On the other hand, by performing printing by the ink jet system, printing with photographic image quality becomes possible, and an advertising medium or a recording material for information service to customers can be used, which can be used as a sales promotion means.

The ink jet system can be used for various purposes, and as an example, application of a special ink is also possible. The application of the special ink was possible only by printing on a conventional thermal paper in advance, but according to the present invention, it is visible because it does not emit light with a specific wavelength irradiation luminescent ink, that is, irradiation light by visible light. Printing with ink that emits light with a specific wavelength such as ultraviolet light,
Printing with a specific scent such as perfume is also possible. The former is effective in preventing unauthorized use such as refund of returned goods, and the latter is effective in promoting sales. As a result, the printing freedom of the issuer is expanded. In terms of cost, the present invention can realize the functional purpose of the present invention by adopting the direct thermal method and the inkjet method, which are widely used in the present apparatus, to reduce the apparatus cost. The printing cost can be kept low.

[Brief description of drawings]

FIG. 1 is a sectional view of a composite recording material of the present invention.

FIG. 2 is a schematic diagram when direct thermal printing is performed on the composite recording material of the present invention.

[Explanation of symbols]

1 Composite recording material 2 base sheet 3 heat sensitive agents 4 Thermosensitive coloring layer 5 Ink absorption layer 11 heating element 12 Colorless dyes such as leuco dyes 13 Developers such as phenolic acidic substances 14 Colored part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroki Kobe             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation (72) Inventor Hiroyuki Onishi             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation F term (reference) 2C056 EA01 EA04 EA30 FB03 FC06                 2H026 AA07 AA15 BB01 FF11                 2H086 BA12 BA15 BA41

Claims (4)

[Claims] 1. A heat-sensitive coloring layer having a base sheet, wherein a heat-sensitive agent that develops color by exposure or heating is applied to one surface of the base sheet, and a transparent ink absorbing layer is formed on the heat-sensitive coloring layer. Composite recording material to be equipped. 2. The composite recording material according to claim 1, further comprising a water resistant layer formed between the thermosensitive coloring layer and the ink absorbing layer. 3. The composite recording material according to claim 1, wherein the porosity of the ink absorbing layer is 10% or less. 4. The composite recording material according to claim 1, wherein the ink absorption layer has a transmittance of 50% or more.