JP2719922B2 - Recording material for impact printer - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel recording material for an impact printer, and more particularly to a method for printing with a full-color wire dot printer or the like to give characters and figures of extremely clear print quality. Overhead projector (hereafter,
OHP).

(Prior art) Impact printers use wires or hammers,
For example, oil-based ink carried on the ink ribbon,
The recording is performed by transferring the image to a recording material.

This impact printer can print on ordinary plain paper, and is not limited by paper quality or paper thickness.
Can be used in a wide range. Furthermore, since the printing method has higher reliability and stable printing quality than other printing methods, it is currently used in a wide range.

On the other hand, OHP is a projector that transmits light to a transparent sheet on which characters and figures are printed and projects the characters and figures on the sheet onto a screen. The sheet used for the OHP (hereinafter, referred to as an OHP sheet) has an ink receiving layer formed on a transparent substrate. Most of the printing on the ink receiving layer of the OHP sheet is not performed by the above-described impact printing method. Moreover, in recent years, multicolor printing on an OHP sheet using a full-color wire dot printer or the like has often been performed along with colorization of images.

(Problems to be Solved by the Invention) However, since the ink used in the impact printer is used by being carried on the ribbon, it is an essential condition that the ink be a slow drying ink that does not dry the ink on the ribbon. Inks are produced by dissolving or dispersing dyes, pigments, additives, resins, etc. in extremely low-volatile solvents.However, since they are slow drying, when printed on an OHP sheet, they are simply added to the surface of the ink receiving layer. If it is not absorbed to the inside while adhering, it will not dry forever.

And, as described above, when multicolor printing is performed on an OHP sheet using a full-color wire dot printer or the like, if the drying of the ink on the ink receiving layer is slow, it is normal that the printing portion is rubbed even if it is slight. A phenomenon in which the ink is dragged to the non-printing portion, which is called tailing, appears, and a clear image cannot be obtained. Further, since the ink does not dry forever, there is a problem that ink is removed when the ink is overlapped or rubbed with a finger.

In order to solve this problem, a number of proposals have been made for improving the adsorption and fixing of ink on an OHP sheet (Japanese Patent Application Laid-Open No. 61-237679). Attempts have been made, but no satisfactory results have been obtained, and it was created using an impact printer.
At present, OHP sheets are inferior to those made with inkjet printers and thermal transfer printers.

In order to develop a recording material for an impact printer capable of obtaining high-quality printing, the present invention has conducted experiments on various high-molecular substances. Styrene copolymer resin) absorbs and fixes the above-mentioned slow-drying ink.

(Means for Solving the Problems) The present invention has been completed based on the above findings,
The present invention proposes a recording material for an impact printer in which an ink receiving layer is formed by coating a coating material containing a styrene copolymer resin as an essential component on a transparent base material.

The second invention proposes a recording material for an impact printer in which a coating material containing a styrene-based copolymer resin and powder as essential components is applied on a transparent base material to form an ink resin layer.

The base material used in the present invention is specified by the use of the recording material, and the composition and form of the base material are not particularly limited as long as the base material can withstand the impact of an impact printer. As a recording material for OHP which is a main object of the present invention, it is essential that a plastic sheet material is transparent, for example, polyethylene terephthalate,
Polycarbonate, polyacetal, polypropylene,
Although a transparent film such as polyvinyl chloride is used, biaxially stretched polyethylene terephthalate is most suitable in the present invention.

The thickness of the substrate can be appropriately selected according to the purpose of the printer, but is preferably in the range of 25 to 200 μm, and 50 to 100 μm.
m is optimal.

In the present invention, examples of the styrene copolymer resin include styrene / acryl, styrene / methacryl, styrene / maleic copolymer resin, and esters thereof. In addition, acrylonitrile / acryl / styrene (AAS), acrylonitrile / Ethylene propylene diene monomer / styrene (AES), acrylonitrile / styrene (AS), acrylonitrile / butadiene /
Copolymer resins such as styrene (ABS) and methyl methacryl / butadiene / styrene (MBS) can also be used.

Particularly preferred among these are styrene / acrylic, styrene / maleic acid copolymer resins and their esterified products, but these are generic names and may include derivatives thereof in addition to styrene, Terpolymers obtained by adding other polymerization monomers are also included. In any case, those having various polymerization ratios are commercially available.

In the present invention, a styrene copolymer resin having any copolymerization ratio can be used, but the molar ratio of a comonomer (a monomer copolymerizable with styrene) to styrene is 1/3 to 4%.
Are the most suitable.

On the other hand, the powder used in the second invention can be appropriately selected from those having good dispersibility in the coating composition and good transparency. For example, inorganic powders such as silica, calcium carbonate, titanium oxide, talc, clay, and barium sulfate. Also, organic fine powders composed of acrylic resin, cross-linked polystyrene resin, acrylic styrene copolymer, benzoguanamine resin, nylon resin, epoxy resin, phenol resin and the like can be used.

Those obtained by subjecting these powders to hydrophobic treatment with silanes can also be used.

In addition to the above components, a dispersant, an ultraviolet ray inhibitor, an optical brightener, an antioxidant, an anti-settling agent, a plasticizer, and the like may be added to the coating composition within a range that does not impair the effects of the present invention. it can.

These coating compositions are appropriately dissolved or dispersed in a solvent and applied as a solution coating on the substrate.

The solvent used here may be any solvent that dissolves the styrene-based copolymer resin and can uniformly disperse the powder, such as lower alcohols, glycol ethers, esters, ketones, ammonia and amino. Water to which an alkaline substance such as alcohols is added can also be used. The above solvents can be used alone or in combination of two or more.

The coating thickness when applying the coating agent, the dry thickness is 0.1
It is sufficient if it is not less than μm, and in consideration of performance and economy, 0.5 to 20 μm is appropriate, but optimally 1 to 5 μm. Note that this does not apply when the particle diameter of the powder is large.

Further, as a coating method, an air knife coater, a bar coater, a hot melt coater method or the like can be adopted.

(Effect of the Invention) In summary, the recording material according to the present invention is placed on a base material,
The ink receiving layer is formed by applying a coating material containing a styrene-based copolymer resin as an essential component.According to the research conducted by the present inventors, the styrene-based copolymer resin is transferred from an ink ribbon by an impact printer. The absorbed slow drying ink is absorbed and fixed in a short time. Therefore, clear characters and figures are printed on the ink receiving layer.

It is not clear why the styrenic copolymer resin fixes the slow-drying ink in a short period of time, but the resin contains styrene groups at an appropriate ratio, making it compatible with ink solvents and additives. And the ink is considered to be fixed to the resin.

On the other hand, the second invention can solve the drawbacks when using the styrene copolymer resin alone by adding the powder described above as the coating composition. That is, effects such as prevention of tailing, addition of strength to the coating layer, and prevention of blocking during handling and storage can be obtained.

In addition, when powder is added to the coating material for coating, irregularities are formed by the powder fixed to the surface of the ink receiving layer, but it is estimated that the above-described effect is caused by the irregularities due to the powder. You. Therefore, the above-mentioned effect becomes larger as the particle size of the powder increases, but when projected onto a screen by the OHP, the image becomes black and becomes unsightly.

According to experiments performed by the inventors of the present invention, the average particle size was 0.1 μm to 5 μm.
When the particle size is smaller than the above range, the effect of preventing tailing is poor. When the particle size exceeds the range, the image quality deteriorates.

In the case of powder for resin, the weight ratio is 5 / 1000-
5/100 was optimal. If the amount is less than this range, the tailing prevention effect is poor, and the soft resin does not have sufficient blocking prevention effect. If the amount is larger than this range, the haze becomes high and the image becomes dark when projected on a screen, so that it is unsightly.

(Example) Hereinafter, an example of the present invention will be described.

75μm polyester film (Toray: brand name
Lumirror T) is coated with a coating agent of each of the following formulation examples using a bar coater # 10 and dried at 130 ° C. for 3 minutes to prepare a transparent OHP sheet for an impact printer.
The tailing, transparency, blocking property, and ink fixing property were evaluated.

Evaluation criteria (1) Print quality Fujitsu full-color wire dot linter (DL-
2400), and those obtained by OHP with extremely clear prints were evaluated as ○, those that were clear but had some tailing were rated Δ, and those that had tailing and were unclear were rated x.

(2) Transparency The haze was measured with a haze meter (MODEL TC-H III, manufactured by Tokyo Denshoku Co., Ltd.). Above 15%, it darkens on the screen.

(3) Blocking property The surface to be treated and the surface to be treated are adhered to ^each other, and a pressure of 10 g / cm ² is applied. The temperature is maintained at 20 ° C and 65%. When the coating layer is broken due to noise when peeling off,
And

(4) Ink fixability Measure the time until the ink stops trailing even when the printed portion is rubbed with a finger.

Claims (3)

(57) [Claims] 1. A styrene / acrylic, styrene / acrylic
Methacryl, styrene / maleic acid copolymer resin and their esters, acrylonitrile / acryl / styrene, acrylonitrile / ethylene propylene diene monomer / styrene, acrylonitrile / butadiene / styrene, polymer copolymer selected from methyl methacryl / butadiene / styrene A recording material for an impact printer, wherein an ink receiving layer is formed by applying a coating agent containing coalescing as an essential component. 2. A styrene / acrylic, styrene / acrylic
Methacryl, styrene / maleic acid copolymer resin and their esters, acrylonitrile / acryl / styrene, acrylonitrile / ethylene propylene diene monomer / styrene, acrylonitrile / butadiene / styrene, polymer copolymer selected from methyl methacryl / butadiene / styrene A recording material for an impact printer, characterized in that a coating agent containing a coalescence and a powder as essential components is applied to form an ink receiving layer. 3. The recording material for an impact printer according to claim 2, wherein the powder contains a powder having an average particle size of 0.1 μm to 5 μm.