JPS63280253A - Electrostatic recording body - Google Patents

Abstract

PURPOSE:To obtain electrostatic recording paper which decreases scumming by providing specific roughness to the surface of a dielectric layer consisting of a white pigment and dielectric resin. CONSTITUTION:The dielectric layer of the electrostatic recording body having the dielectric layer consisting of the white pigment 3 and the dielectric resin 2 on a base 1 is so formed that the 10 point average roughness of the surface of said layer is >=10mum and that many projecting parts smaller than the main projecting parts forming the average roughness exist between the groups of such projecting parts. Namely, the flocculated particles 3 of the pigment fixed by the dielectric resin 2 on the surface of the base 1 act as a spacer and the grain sizes of the flocculated particles 3 are distributed in an adequate range so that the projecting parts having different heights exist at adequate dispersion. The gap suitable for electric discharge is thus obtd. The scanning of the non- image part is decreased.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an electrostatic recording medium, and particularly to a CAD (Computer
The present invention relates to an electrostatic recording medium that is particularly free from background stains and color unevenness, and is particularly suitable for use in color electrostatic plotter printers used for output of computer aided design and remote sensing.

[Prior art] The electrostatic recording method is a method in which a voltage pulse is applied from one or both sides of an electrostatic recording medium in which a recording layer mainly composed of an insulating resin is provided on one side of a conductive-treated support. This is a method in which an electrostatic latent image is formed on the recording layer, and this is developed with a dry toner or developer to make it visible.

It is especially used in facsimiles, high-speed plotter printers, etc. because it is a method with excellent recording speed and resolution.

The recording layer used in an electrostatic recording medium is an insulating layer that retains electrostatic charge, and its main components are an insulating resin and a powder pigment. This recording layer is known to have a 10-point average roughness of 9.0 μm or less in conventional electrostatic recording paper. This is because the degree of unevenness on the surface of the recording layer as a discharge gap is adjusted so as not to deviate greatly from Paschen's discharge start curve so that sufficient discharge can be obtained during recording.

Conventionally, in Japanese Patent Publication No. 56-33703, as shown in Fig. 2, the range of the size of the spacer, which is the agglomerated particles 3 of pigment on the support 1, has been expanded to io and ie μm, but the area other than the spacer is completely It is flat. In this case 10.16μ
The value around m is quite large for a spacer. With this large discharge gap, it is very difficult to discharge, and only images with too low density can be obtained as actual images.

The cause of background staining is that when an electrostatic latent image is developed with electrostatic toner in the developing section in the wet method, the convex part of the dielectric layer of the electrostatic recording paper rubs against the developing section, and the electrostatic toner adheres there. It is thought that this is because the toner is contaminated (Japanese Patent Publication No. 56-1427). The degree of contamination varies depending on the combination of toner and resin materials and the size of the contact area with the developing section.

Therefore, if a resin with excellent fixing properties is used at this time, strong background stains may occur in non-image areas. Furthermore, even if a resin that does not cause a lot of staining is used, stains rarely become large when using paper that has a small contact area with the developing section and in the color electrostatic recording method in which voltage application and development are repeated multiple times.

[Objective] It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide an electrostatic recording paper with less background staining, especially as an electrostatic recording paper used in a color electrostatic recording method.

[Structure] As described in the claims, the structure of the present invention to achieve the above object is an electrostatic recording material having a dielectric layer made of a white pigment and a dielectric resin on a support. The ten-point average roughness of the surface of the layer is 10 μm or more, and
This electrostatic recording material has a large number of smaller convex portions between the main convex portion groups forming this average roughness.

That is, in the present invention, the particle size of the pigment is preferably 6.0 μm.
The above describes the type of pigment/resin, pigment/resin ratio (preferably between 1/4 and 5/1), dispersion conditions (dispersion means, time,
An electrostatic recording material having a dielectric layer having a ten-point average roughness of 10 μm or more, preferably 10 to 20 μm, by adjusting pigment aggregation caused by changing the solid content (solid content) to provide a recording layer with almost no background staining. This is related to.

Conventionally, if the roughness becomes too large, negative aspects such as line breakage, color unevenness, and a decrease in print density will appear as a result of a decrease in discharge efficiency. However, in the case of the present invention, although a very slight decrease in print density was observed, abnormalities such as color unevenness and line breakage could be suppressed within the range of the print voltage adjustment of the electrostatic plotter.

This is thought to be due to the presence of convex portions with different heights with appropriate variations, resulting in a gap suitable for discharge.

That is, the electrostatic recording material of the present invention, as shown in FIG.
Aggregated pigment particles 3 fixed on the surface of support 1 with dielectric resin 2 act as spacers, and the particle diameters of these aggregated particles 3 are distributed within an appropriate range.

Pigments include oxides, hydroxides, carbonates, nitrates, halides such as zinc, titanium, magnesium, calcium, and aluminum, and inorganic powders such as silica, alumina, bentonite, attapulgite, kaolin, calcined kaolin, and calcined calcium silicate. and organic matter-treated powders of these inorganic powders are used.

Insulating resins include alkyd resin, silicone resin,
Epoxy resin, melamine resin, phenolic resin, polystyrene resin, vinyl chloride resin, nylidene chloride resin, vinyl chloride/vinyl acetate copolymer resin, styrenated alkyd resin, styrene/butadiene copolymer resin, polyacetal resin, polybutyral Resins, saturated or unsaturated polyester resins, polyurethane resins, acrylic acid resins, maleic acid resins, etc. are used.

Hereinafter, the present invention will be specifically explained with reference to Examples. Note that all amounts (parts) of components in the examples are parts by weight.

The roughness is a 10-point average roughness, and is 5E-
Using a 3A surface roughness meter, X-axis magnification is 100x, Y-axis magnification is 2.
Measured at a magnification of 0.000 times and calculated at a processing length of 0.8 mm (J
IS 80601-76).

Example 1.

Using plain paper with a thickness of 55 μm as a support, a liquid consisting of 50 parts of Chemistat 5500 (Sanyo Chemical Co., Ltd.) and 50 parts of methanol was applied as an impregnating liquid using a wire bar of 0.3 mm and dried, resulting in a coating weight of 4.0 g/m2.
A conductive substrate (hereinafter referred to as A base) was obtained by impregnating the conductive substrate to a concentration of 2 and calendering.

A recording layer was formed by dispersing a solution consisting of 110 parts of a vinyl toluene resin [7 Pryolide (manufactured by Gutdeyer), 10 parts of calcium carbonate powder with an average particle size of 15 μm, and 80 parts of toluene in a grain mill, and coating amount 5±ig/+n2. I applied it and let it dry.

When an image was produced using an electrostatic plotter V-80 (print voltage adjustment: MAX) manufactured by Versatic Co., Ltd., good results were obtained with little rubbing and staining, as shown in Table 1 below.

Example 2 The same base A as in Example 1 was used, and as a recording layer, 10 parts of a copolymer resin [LR-472 manufactured by Mitsubishi Rayon Co., Ltd.] containing methyl methacrylate as a main component was added.
5m calcium carbonate powder 5 parts toluene
A solution consisting of 85 parts was dispersed using an attritor, applied to a coating amount of 5±10/m 2 and dried.

Example 3 The same base A as in Example 1 was used, and as a recording layer, 110 parts of a copolymer resin mainly composed of polyester [Vylon/2033 (manufactured by Toyobo Co., Ltd.)] 20 parts of calcium carbonate powder with a particle size of 6.5 μm A solution consisting of 70 parts of toluene was dispersed in a ball mill, coated to a coating amount of 7±1(]/m2, and dried.

Comparative Example 1 The same base A as in Example 1 was used, and a copolymer resin containing methyl methacrylate as a main component was added to it as a recording layer.
LR-472 (manufactured by Mitsubishi Rayon Co., Ltd.)] 110 A solution consisting of 5 parts of calcium carbonate powder with a part diameter of 6.5 μm and 85 parts of toluene was dispersed with an attritor, applied to a coating amount of 5 ± 1 g/m' and dried. .

Table 1 [Effects] As explained above, by adjusting the surface of the dielectric layer of an electrostatic recording medium, if the ten-point average roughness is made 10 μm or more, the non-image area will be reduced even if conventional resin is used as is. The amount of dirt on the scalp is drastically reduced.

As a result, the present invention exhibits excellent effects as an electrostatic recording material for a color electrostatic plotter that is subjected to electrostatic application and development multiple times.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view for explaining the structure of an electrostatic recording medium of the present invention, and FIG. 2 is a schematic cross-sectional view for explaining the structure of a conventional electrostatic recording medium. DESCRIPTION OF SYMBOLS 1...Support, 2...Dielectric resin, 3...Agglomerated particles of pigment,

Claims (1)

[Scope of Claims] An electrostatic recording material having a dielectric layer made of a white pigment and a dielectric resin on a support, wherein the surface of the dielectric layer has a ten-point average roughness of 10 μm or more, and this average roughness An electrostatic recording material characterized in that between a group of main convex portions forming a main convex portion group, there are many convex portions smaller than the convex portions.