JPS60145879A - Recording sheet - Google Patents

Abstract

PURPOSE:To obtain a transparent recording sheet for an ink jet printer which is suited for overhead projector by a method wherein a film of a mixture of PVA of high saponifiability and polyvinyl pyrrolidone is formed on a transparent substrate. CONSTITUTION:A film of a mixture of polyvinyl alcohol having a saponifiability of 75% or above and polyvinyl pyrrolidone is formed by coating by a method of gravure coating or the like at least on one surface of a transparent substrate of a polyester film, an acetate film or the like, so as to obtain an aimed recording sheet. An appropriate mixing ratio of polyvinyl alcohol with polyvinyl pyrrolidone is about 9.5:0.5-0.5:9.5. The recording sheet thus obtained has an effect of drying ink for an ink jet printer containing pyrrolidone compound, in particular, in a short time, thus enabling rapid printing and recording.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recording sheet for an inkjet printer. More particularly, the present invention relates to transparent recording sheets comprising a transparent support and an inkjet printer recordable coating.

Background Art Inkjet printers have become popular in recent years due to their excellent features such as sharpness of recording, quietness, and ease of color printing. Inkjet printers use ink that does not dry easily to prevent clogging of the jet nozzle, and the components of this ink are binder and dye.

Solvents, additives, etc. are generally referred to as water.

Therefore, when printing is performed using an inkjet printer, the recording material must have mature properties, and paper specially designed to provide sufficient ink absorption properties is usually used.

On the other hand, as inkjet printers become more color-oriented, there is an increasing demand for recording on transparent recording materials and using them as base paper for overhead projectors (OHP). However, the transparent recording material is usually made of plastic film, which is hydrophobic and does not absorb any inkjet printer ink, so ink recorded directly on it does not dry easily and can be used with fingers. If they are rubbed or overlapped, the recorded area will get dirty and become unusable.

Various proposals have been made to improve this, but all are insufficient.

OBJECT OF THE INVENTION The present inventors have arrived at the present invention as a result of intensive research to develop a recording sheet that is a transparent recording material and on which ink for inkjet printers dries in a short time.

Therefore, an object of the present invention is to provide a recording sheet comprising a transparent support and a film that can be rapidly recorded with an inkjet printer. A further object of the invention is to provide a record sheet useful for overhead projects. Another object of the present invention is to provide a recording sheet on which the ink for an inkjet printer containing a pyrrolid compound dries in a short time and enables quick printing.

Structure and Effects of the Invention An object of the present invention is to provide a recording sheet characterized in that a film consisting of a mixture of polyvinyl alcohol and polyvinylpyrrolidone with a degree of saponification of 75% or more is formed on at least one side of a transparent support. This is accomplished by K.

In the present invention, the transparent support is preferably a transparent plastic film, such as a polyester film,
Poly7 mid film.

Examples include acetate film, polycarbonate film, and polyvinyl chloride film.

The thickness of the support used is usually 25 to 200 .mu.m, preferably 50 to 150 .mu.m. If it is too thin, it will lack rigidity and it will be difficult to insert it into an inkjet printer, and if it is too thick, it will be difficult to handle and the price per sheet will increase, so both are unfavorable.

In addition, the polyvinyl alcohol referred to in the present invention has a saponification degree of 75.
Must be at least 100%. If the degree of saponification is less than 75 degrees, the compatibility with polyvinylpyrrolidone becomes poor, so it is not preferable. Polyvinyl alcohol with a degree of saponification of 80% or more is more preferably used. As such polyvinyl alcohol, one of commercially available polyvinyl furfurs that satisfies the above conditions can be used.

In addition, polyvinylpyrrolidone has a molecular weight of 10,00
A molecular weight of 0 to 1,000,000 can be used, but preferably a molecular weight of 15,000 to 200,00.
0. Commercially available polyvinylpyrrolidone in this range can be used.

The appropriate mixing ratio of polyvinyl alcohol and polyvinylpyrrolidone is 9.5:o, s to o, 5:9.5, preferably 9:1 to 1:9 from the viewpoint of drying properties of the ink. The skin of the mixture formed has a dry thickness of 1 to 20
μ, 5! A suitable thickness is 2 to 15μ. If the film is too thin, the ink will dry slowly and become impractical; if the blade is too thick, the price per sheet will increase and coating will be difficult.
1iAL, so neither is preferable.

As a method for forming a film on a transparent support, conventional coating means such as gravure coating, barcode coating, reverse coating, knife coating, etc. can be used.

The recording sheet of the present invention is useful for printing using an inkjet printer, and further for printing using an ink for an inkjet printer containing a hyrolidone compound. The specific composition of such ink is as follows:
Examples are described in Japanese Patent Application Laid-Open Nos. 58-174457 to 174472.

Example Next, the present invention will be explained with reference to Examples.

Examples and Comparative Examples Jl! On one side of a 00 μ polyethylene terephthalate film, polyvinyl alcohol with a saponification degree of 86 degrees and polyvinyl pyrrolidone with a molecular weight of about 40.0 1) O (-30 to rubiscoll; BASFj
1/2 was mixed in the ratio shown in Table 1, and an aqueous solution (15% concentration) was applied with a bar caulk to a dry thickness of 5 μm.

The ink drying properties of the obtained recording sheet were examined using an ink obtained by uniformly mixing 25 parts by weight of ethylene glycol, 20 parts by weight of N-methyl-2-pyrrolidone, 3 parts by weight of dye, and 52 parts by weight of water. . The results are shown in Table 1.

Table 1 *Polyvinyl alcohol, **Polyvinylbipridone.

***Time until stains no longer occur even when rubbed with fingers From the table above, it can be seen that the combined use of polyvinyl alcohol and polyvinylpyrrolidone significantly shortens the drying time of the ink.

Claims (1)

[Claims] A recording sheet characterized in that a film made of a mixture of polyvinyl alcohol and polyvinylpyrrolidone having a degree of saponification of 75 or more is formed on at least one side of a transparent support.