JPS63155045A - Electrostatic recording body - Google Patents

Abstract

PURPOSE:To prevent tinting and scumming by allowing an antistatic agent to exist at 1.0X10<-3>-5.0X10<-1>g/m<2> in or on a dielectric layer. CONSTITUTION:The antistatic agent is made to exist at 1.0X10<-3>-5.0X10<-1>g/m<2> in or on the dielectric layer. The antistatic agent and above all, nonionic antistatic agent are easily dissolved or uniformly dispersed in a dielectric layer paint or can be uniformly coated on the dielectric layer in the case of forming the dielectric layer by coating a solvent type paint. The uniform dispersion or dissolution in the solvent type dielectric layer paint for uniform coating thereof on the dielectric layer is possible if a hydrophobic group or hydrophobic high-polymer chain is further introduced into the nonionic or ionic antistatic agent. The tinting and scumming are thereby prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrostatic recording medium, and more particularly to an electrostatic recording medium that can provide clear recording without streaks, scumming, etc.

(Prior art) Electrostatic recording has traditionally been used as a high-speed recording method in facsimiles, printers, etc., but in recent years, CAD, which uses computers to perform design and drawing, has become popular.
An electrostatic printer/electrostatic plotter is used for the output of the system. In the conventional record based on text, 2
About OO dots/inch was sufficient, but such CA
For outputting drawings such as the D system, high-resolution recording of approximately 400 dots/inch and minimal staining are required. Incidentally, many of the drawings output from the CAD system are wide, and in order to achieve uniform development, liquid development is the mainstream.

In the liquid development method, the toner particles are finer than in the powder development method, so in the electrostatic recording method, in addition to the latent image for the recorded image, even a low potential charge generated by friction etc. tends to appear as dirt. However, in records such as drawings, there is a possibility that such stains may be mistaken for changes in the design, so improvements are required even if the slight stains that occur are overlooked in conventional written records. is the current situation.

Such stains include streaks and background stains on the white paper area, but streaks are the stains that occur when the electrostatic recording medium is rubbed by a slight convexity on a part of the edge of the recording electrode. This refers to a phenomenon in which only a portion is triboelectrically charged and appears as streak-like stains after development.These streaks often reach a length of several meters or more, and electrostatic recording materials for CAD are particularly required to be free of streaks. Background smearing is a phenomenon also called Capri, in which the entire surface of an electrostatic recording medium is charged to a low potential, and after it is developed with toner, even the blank areas where there is no recording are recorded with a low image density. say.

Conventionally, grounding has been dealt with by conducting conductive treatment on the back side of the electrostatic recording medium to release the low-potential charges that cause stains, but this method alone cannot meet the current high requirements. The current situation is that this is simply not possible.

(Problems to be Solved by the Invention) The present invention is an electrostatic recording method that can obtain clear images without streaks or scumming in an electrostatic recording method, particularly in a high resolution electrostatic recording method such as 400 dots/inch. The purpose is to provide the body.

(Means for Solving the Problem) For the above purpose, the inventors of the present invention have conducted intensive research and found that in the dielectric layer, which originally needs to have good insulation in order to maintain a high recorded image density, Alternatively, the inventors have discovered that the above problems can be solved without sacrificing image density by containing a certain amount of an antistatic agent on the dielectric layer, and have completed the present invention.

That is, the present invention provides an electrostatic recording material comprising a dielectric layer formed on a conductive support, in which the dielectric layer contains 1.0X10-' to 5.0X10-'g/ m
This is an electrostatic recording material characterized by the presence of the antistatic agent No. 2.

(Function) The antistatic agents used in the present invention include polyoxyethylene ethers such as polyoxyethylene alkyl ether and polyoxyethylene alkylphenyl ether, which are nonionic antistatic agents, polyoxyethylene stearate, and polyoxyethylene stearate. These include polyoxyethylene derivatives such as fatty acid esters of polyoxyethylene such as ethylene stearate, various derivatives of polyoxypropylene, or copolymers of both, glycerides such as glycerol laurylate and glycerol stearate, and cationic antistatic agents. Examples include alkyltrimethylammonium chloride, polyoxyethylene alkylamine, alkylamine acetate, etc., anionic antistatic agents include sodium alkylbenzenesulfonate, sodium fatty acid, etc., and amphoteric antistatic agents include alkylbetaine, alkylglycine, etc. etc. are exemplified. Among the above antistatic agents, especially nonionic antistatic agents, when a dielectric layer is formed by coating a solvent-based paint, they are easily dissolved or uniformly dispersed in the dielectric layer paint, or are easily dispersed on the dielectric layer. It is more preferably used because it can be applied uniformly. Furthermore, if a hydrophobic group or a hydrophobic polymer chain is further introduced into the above-mentioned nonionic or ionic antistatic agent, it can be uniformly dispersed or dissolved in a solvent-based dielectric layer coating, or it can be applied uniformly on a dielectric layer. more preferable. If the content of the antistatic agent is too low, there will be no stain improvement effect, while if it is too high, the density of the recorded image will decrease, so the content should be 1.0×.
It is prepared in the range of 10-3 to 5.0 x 10-'g/m2, more preferably 5.0 x 10-'' to 2.0xlO-'g/m2.

Polymer electrolytes, typified by conductive agents used to impart conductivity to the support of electrostatic recording materials, have 20 to 100 monomers containing anions or cations, and have hydrophilic properties. It is very strong and has a molecular weight of several thousand or more, so it cannot be uniformly dispersed in a solvent-based dielectric layer paint, and even if it is coated on a dielectric layer, it cannot be applied uniformly. For this reason, when a polymer electrolyte is used, there is a drawback that a portion is created where the charge for image recording is lost, resulting in so-called white spots in the recorded image.

In the present invention, the presence of an antistatic agent in or on the dielectric layer means to include the antistatic agent in the dielectric layer or to form a layer containing the antistatic agent on the dielectric layer. Although the method is not particularly limited,
A method in which an antistatic agent is dissolved or dispersed in a dielectric layer paint, which is usually a container type, using a stirrer or an attritor, and then applied to a conductive support using a bar coater, or a paint containing an antistatic agent is applied statically. Examples include a method of coating the dielectric layer of the electrical recording material using a bar coater or the like, or a method of spraying it.

In the present invention, it is possible to eliminate streaks and background stains without causing problems such as a decrease in recorded image density or the occurrence of white spots. It is presumed that this is because it functions to effectively release electric potential charges.

As the conductive support for forming the electrostatic recording medium, conductive agents such as cationic polymer electrolytes such as polyvinylbenzyltrimethylammonium chloride, or anionic polymer electrolytes such as sodium polystyrene sulfonate,
Impregnating or coating an inorganic salt such as sodium chloride, or a conductive pigment such as conductive zinc oxide, which is zinc oxide doped with aluminum, or conductive tin oxide, which is tin oxide doped with antimony, increases the surface resistivity to 10'. ~
Paper, plastic film, etc. with a resistance of 10"Ω are used. Resins for the dielectric layer constituting the electrostatic recording medium include polyvinyl acetate, polyvinyl butyral, polyester,
Insulating resins such as polymers and copolymers of methacrylic acid esters such as methyl methacrylate and butyl methacrylate, and acrylic esters are used, and the pigments mixed with these include calcium carbonate, titanium oxide, amorphous silica, and calcined silica. There are dyes, plastic pigments, etc.

(Examples) Examples of the present invention will be described below, but it goes without saying that the present invention is not limited to these Examples. still,
The parts shown below each represent parts by weight.

Example 1 A cationic polymer electrolyte (trade name: Chemistaso 6300° manufactured by Sanyo Chemical Co., Ltd.) was applied to the surface of a high-quality paper of 1 tsubo 1 x 53 g/m2 at an absolute dry weight of 3 g/m'', and further 2 g/m2 on the back side. A conductive support was formed by coating. 50 parts of polyvinyl butyral resin and 50 parts of surface-treated calcium carbonate were melted and dispersed in a solvent consisting of 100 parts of methyl ethyl ketone and 100 parts of toluene using a stirrer. A paint containing 0.5 part of an ionic antistatic agent (trade name: Anjotoru 2 B, manufactured by Kao Soap Co., Ltd.) was applied to the surface of the conductive support at an absolute dry weight of 5 g/min.
An electrostatic recording medium was prepared by applying m2.

Example 2 50 parts of polymethyl methacrylate resin and 50 parts of surface-treated calcium carbonate were dissolved and dispersed in 200 parts of toluene using a stirrer, and placed on the same conductive support as used in Example 1 with an absolute dry weight of 5 g/ m” coating, and then a nonionic antistatic agent made of polyoxyethylene derivative (product name:
An electrostatic recording medium was prepared by dissolving 10 parts of Niregan S-100 (manufactured by Nippon Oil & Fats Corporation) in 90 parts of methyl ethyl ketone and applying a solution of 0.1 g (absolutely dry weight) to 7 m 2 using a Meyer bar.

Example 3 Polyester resin (product name: Pylon 20S.

67 parts (manufactured by Toyobo Co., Ltd.), 30 parts of a surface-treated baked sheet, a high molecular weight nonionic antistatic agent consisting of a polyoxyethylene-polyoxypropylene derivative into which a hydrophobic group has been introduced (product name: Diskol 206, No. Manufactured by Ichi Kogyo Seiyaku Co., Ltd.) 3
Example 1
on the same conductive support as used in
m'' coating to prepare an electrostatic recording material.

Comparative Example 1 An electrostatic recording material was prepared in the same manner as in Example 2 except that the nonionic antistatic agent solution was not applied.

Comparative example 2 Polyester resin (product name: Byron 20S.

Toyobo Co., Ltd.) 67 parts, surface treated fired seams 30 parts, 4
Cationic polymer electrolyte containing class ammonium salt (
The product used in Example 1 was prepared by dispersing 3 parts of dried powder of Chemistuf 1-6300 (trade name: manufactured by Sanyo Chemical Co., Ltd.), 100 parts of toluene, and 100 parts of methyl ethyl ketone using a stirrer, followed by dispersion treatment for 1 hour using a sand grinder. An electrostatic recording material was prepared by coating the same conductive support with an absolute dry weight of 5 g/m''.

Comparative example 3 Polyester resin (product name: Hiron 20S.

70 parts (manufactured by Toyobo Co., Ltd.) and 30 parts of a surface-treated baked dye were dissolved and dispersed in a solvent consisting of 100 parts of toluene and 100 parts of methyl ethyl ketone using a stirrer, and the mixture was placed on the same conductive support as used in Example 1. An electrostatic recording medium was prepared by applying the coating at an absolute dry weight of 5 g/m''.

A recording test was conducted on each of the above electrostatic recording bodies using an electrostatic block for CAD EP-101 manufactured by Matsushita Densen ■, and the recorded image density and background stain density in the margin area were measured using an image densitometer RD-1.
0OR, manufactured by Maches Co., Ltd.) as shown in Table 1. Furthermore, streaks in the recorded image and white spots in the recording were visually evaluated, and the results are also shown in Table 1.

All of the antistatic agents used in the present invention (Examples 1 to 3) dissolve well in the dielectric layer coating solution or can be uniformly coated on the dielectric layer. The ionic antistatic agent showed particularly excellent coating properties and solubility. The recorded image of the electrostatic recording medium according to the present invention was free from streaks, background stains, and white spots, and the recorded image density was good (Figure 1).
.

On the other hand, in Comparative Example 2, the polymer electrolyte was not dispersed in the dielectric layer coating solution, resulting in white spots in the recorded image (Figure 2), and in Comparative Examples 1 and 3, which did not contain an antistatic agent, streaks appeared. , background stains occurred and good records could not be obtained. FIG. 3 shows a recorded image in Comparative Example 3, with streaks appearing in the center of the figure.

(Effects) The electrostatic recording medium according to the present invention does not cause streaks or background stains and has a high recorded image density, and is particularly suitable as an electrostatic recording medium for CAD systems.

[Brief explanation of the drawing]

FIG. 1 shows a recording sample in Example 3 according to the present invention, and FIG. 2 shows a recording sample including white spots of an electrostatic recording material of Comparative Example 2 in which a polymer electrolyte was contained in the dielectric layer. , FIG. 3 shows a recording sample in which streaks occurred in Comparative Example 3. The evaluation criteria in Table 1 are as follows: Streaks Q: No streaks ×: Streaks occurred White spots O: No white spots ×: White spots occurred

Claims (1)

[Claims] In an electrostatic recording material formed by forming a dielectric layer on a conductive support, 1.0×1
An electrostatic recording material characterized in that an antistatic agent is present in an amount of 0^-^3 to 5.0 x 10^-^1 g/m^2.