JPH0792698A - Electrostatic recording material - Google Patents

Abstract

PURPOSE:To obtain a recording material having an excellent recording density with little contamination due to friction by forming a protective layer containing a charge controlling agent on a dielectric layer and specifying the wt.% of the charge controlling agent to the total solid amt. of the protective layer. CONSTITUTION:A protective layer containing 0.1-10wt.%, preferably 0.5-5.0wt.% charge controlling agent is formed on a dielectric layer. The obtd. electrostatic recording material has little contamination due to friction without decreasing the recording density. If the amt. of the charge controlling agent in the protective layer is <0.1wt.%, the effect to control the frictional contamination can not be obtd. If the amt. exceeds 10wt.%, the recording density decreases. As for the charge controlling agent to be added to the protective layer, a cationic polymer compd. such as polyvinylbenzyl trimethylammonium chloride is used. Or, such a compd. is used that produces the same charge as the charge of the toner when the protective layer is electrified by friction in a recording machine, and for example, metal salt of aromatic carboxylic acid is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic recording body used in information devices such as plotters, printers, and fax machines using an electrostatic recording system.

[0002]

2. Description of the Related Art An electrostatic recording method using a multi-needle electrode has been used in a wide range of industrial fields because it has the advantage that a wide and high speed recorded image can be output. In recent years, an output capable of high-density recording has been demanded along with the progress of communication means, and the electrostatic recording method is excellent in image quality and recording speed. Therefore, a terminal printer of a computer, a facsimile machine, an output device of a CAD system, or It is widely used in various fields such as design design using computer graphics. Furthermore, a 400-dot / inch color electrostatic plotter capable of high-density recording has been developed, and clear color recording can be obtained on a large screen.

In the electrostatic recording system, in an electrostatic plotter or electrostatic printer which normally uses multi-needle electrodes, a recording voltage is applied to the multi-needle electrodes to discharge the surface of the dielectric layer to form an electrostatic latent image. Then, the electrostatic latent image is developed with toner to obtain a visible image. For color recording, black, cyan,
1 by overlapping the four colors of magenta and yellow in order
You are getting one pattern. There are two types of color electrostatic plotters, a single pass type and a multi pass type. The former has four multi-needle electrode heads, each of which has a developing head (cyan, magenta, yellow, black), and an image can be obtained with one sheet of paper. The latter has one multi-needle electrode and four developing heads for each of the above colors. This is a multi-needle electrode head that draws a negative color electrostatic latent image of the first color on the recording surface and develops with a positive polarity developer. After that, the recording medium is once returned to the original position and the next electrostatic latent image is formed and developed on the same surface. An image is obtained by passing the paper 4 or 5 times, but rubbing stains ( Background stains), toner fixability, recording density, recording image quality, etc. are desired to be improved. Above all, when recording an image, the electrostatic recording body is rubbed with the developing device of the electrostatic recording machine, so that the recording surface of the electrostatic recording body is triboelectrically charged, and the toner adhered to the triboelectric charging portion during development. Since stains (background stains) significantly deteriorate the recording image quality, their resolution is urgently needed.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrostatic recording material which is excellent in recording density and has less rubbing stains.

[0005]

In order to solve the problems of the present invention, the inventors of the present invention have developed an electrostatic capacitor in which a dielectric layer containing an insulating resin and a pigment as a main component is provided on a conductive support. In the recording body, a protective layer containing 0.1 to 10% by weight of a charge control agent was provided on the dielectric layer.

[0006]

In general, the characteristics required for an electrostatic recording material are curl, fixing property, writing property, and other practical properties, and recording properties such as rubbing stains, recording density, fine line dropout, and solid uniformity. In order to satisfy these at a high level at the same time, there are many restrictions. For example, there is a method of mixing a charge control agent in the dielectric layer to prevent rubbing and smearing due to triboelectrification, but generally the insulating resin in the dielectric layer and the charge control agent have low compatibility. In addition, the recording density and the solid uniformity of the recorded image decrease.

According to the present invention, a charge control agent having a density of 0.
By providing a protective layer containing 1 to 10% by weight, preferably 0.5 to 5.0% by weight, it is possible to obtain an electrostatic recording material with less scuffing without lowering the recording density. When the concentration of the charge control agent in the protective layer is 0.
If it is less than 1% by weight, the effect of suppressing scratches cannot be obtained, and if it exceeds 10% by weight, the recording density is lowered. The charge control agent added to the protective layer cannot be uniquely determined depending on the type of electric charge (positive or negative electric charge) of the resin in the dielectric layer or the toner in the developer, but is not limited to polyvinylbenzyltrimethylammonium chloride. Cationic polymer compounds, sodium polystyrene sulfonate; sulfone-modified polyvinyl alcohol; anionic polymer compounds such as carboxy-modified polyvinyl alcohol, sodium stearate; antistatic effect for anionic surfactants such as dioctyl sodium sulfosuccinate Excellent compound,
Alternatively, a compound in which the protective layer is rubbed by a recording machine to have the same electric charge as that of the toner, for example, a metal salt of aromatic carboxylic acid, a metal salt of higher fatty acid, chlorinated paraffin, chlorinated polyester, naphthene. Acid etc. are mentioned.

The coating amount of the protective layer is 0.01 to 1.0.
It is desirable to adjust g / m ² , preferably in the range of about 0.05 to 0.5, and if it is less than 0.01 g / m ² , the triboelectrification preventing effect remarkably decreases and the desired effect cannot be obtained. If it exceeds 1.0 g / m ² , the recording density will decrease. In the protective layer, in addition to the charge control agent, polyvinyl alcohol, self-emulsifying acrylic or urethane emulsion, SBR latex, acrylic resin, styrene resin, or other aqueous or hydrophobic resin is used in combination. Calcium, calcined kaolin, kaolin, titanium oxide,
It is also possible to add pigments such as zinc oxide.

The electroconductive support of the present invention may be a surface layer of a support such as paper, film, synthetic paper, non-woven fabric, cloth or the like, or polyvinyl benzyltrimethylammonium chloride or polydimethyldiallylammonium chloride as a conductive agent. , Styrene acrylic acid triethylammonium chloride, conductive zinc oxide, conductive titanium oxide, copper iodide, and the like.

In the conductive layer containing the conductive agent, polyvinyl alcohol, casein, animal and vegetable proteins such as soybean protein, starches, various celluloses such as hydroxyethyl cellulose and methyl cellulose, latexes such as SBR and urethane resin, etc. As an aqueous binder and as a pigment,
For example, it is possible to add clay, deckite, nacrite, kaolin, aluminum hydroxide, magnesium hydroxide, calcium carbonate, calcined clay, amorphous silica, alumina, calcined kaolin, barium sulfate, titanium oxide and the like.

Regarding the ratio of the conductive agent used in the conductive layer and the aqueous binder, the aqueous binder is 1 to 5 relative to the conductive agent.
It is about 100% by weight, preferably about 10 to 100% by weight, and the use ratio of the pigment and the total binder (including the water-soluble ionic polymer electrolyte) is 2% of the total binder with respect to the pigment.
It is preferably adjusted in the range of about 0 to 200% by weight.
The coating amount of the conductive layer is preferably adjusted in the range of about ² to 10 g / m ² , and after the conductive layer is coated, smoothing treatment may be performed by super calendering, mirror surface casting, or the like. In order to obtain a good electrostatic recording material, it is preferable to apply a conductive layer and then perform a smoothing treatment so that the Beck smoothness is 200 seconds or more.

The highly insulating resin used for the dielectric layer of the electrostatic recording medium of the present invention includes methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, isobutyl methacrylate, Acrylic ester copolymers such as 2-ethylhexyl methacrylate and methacrylic acid ester copolymers, vinyl acetate, urea resins, melamine resins, unsaturated polyester resins, epoxy resins, urethane resins, silicone resins,
Existing materials such as polyethylene terephthalate, ethylene-vinyl acetate copolymer, butyral resin, polyester resin, nitrocellulose, polystyrene, styrene-acrylic copolymer, styrene-methacrylic acid copolymer, and phenol resin are used as they are.

Pigments can be added to the dielectric layer, for example, clay, deckite, nacrite, kaolin, aluminum hydroxide, magnesium hydroxide, calcium carbonate, calcined clay, amorphous silica, alumina, calcined kaolin, Examples thereof include barium sulfate, titanium oxide, pigments obtained by insulating the surfaces of these pigments, and plastic pigments. In general, the dielectric layer is a coating solution obtained by dissolving and dispersing an insulating resin or a pigment in a suitable organic solvent such as toluene, methyl ethyl ketone, xylene, etc., for example, a bar coater, a contra coater, a gravure coater, a curtain coater, a chanplex. It is formed by a method of coating on a conductive support with a suitable coating device such as a coater, roll coater, blade coater, and drying. It is also possible to add an auxiliary agent such as a fluorescent dye, a dye, a defoaming agent, a thickener, and a lubricant to each layer, if necessary, within a range that does not interfere.

[0014]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" in the examples mean "parts by weight" and "% by weight" respectively.

Example 1 [Formation of conductive layer] A cationic polymer electrolyte (trade name: Chemistat 7300, manufactured by Sanyo Kasei Co., Ltd.) on both sides of a high-quality paper having a basis weight of 60 g was dried on the front side at 4 g and the back side. 2g
After coating and drying, a smoothing treatment was performed with a super calender so that the smoothness on the surface side was 300 seconds with a Beck smoother, and a conductive layer was formed. [Formation of dielectric layer] 100 parts of toluene, 100 parts of methyl ethyl ketone, A dielectric layer coating liquid obtained by mixing and stirring a composition comprising 75 parts of methyl methacrylate resin and 15 parts of calcium carbonate powder (average particle size 5 μ) was applied to the surface side of the above conductive support on a Mayer bar. And dry weight 3g /
m ² was applied to form a dielectric layer. [Formation of protective layer] Toluene 20 is formed on the dielectric layer.
Part, 20 parts of methyl ethyl ketone, 10 parts of methyl methacrylate resin, and 0.3 g of a dry weight of a protective layer coating liquid consisting of 0.1 part of polyvinylbenzyltrimethylammonium chloride having a quaternization degree of 5 mol% as a charge control agent. An electrostatic recording material having a protective layer was obtained.

Example 2 Electrostatic recording was performed in the same manner as in Example 1 except that 0.4 part of aluminum salicylate was used instead of 0.1 part of polyvinylbenzyltrimethylammonium chloride in the formation of the protective layer of Example 1. Got the body

Example 3 An electrostatic recording material was obtained in the same manner as in Example 1 except that the following dielectric layer coating liquid was used in the formation of the dielectric layer. 50 parts of toluene, 50 parts of methyl ethyl ketone, 35 parts of a copolymer of vinyl chloride and vinyl acetate, and 8 parts of calcined kaolin,
The composition consisting of was mixed and stirred to obtain a dielectric layer coating liquid.

Comparative Example 1 An electrostatic recording body in which a protective layer is not provided on the dielectric layer of Example 1.

Comparative Example 2 As in Example 1 except that in the formation of the protective layer of Example 1, 2.0 parts of polyvinylbenzyltrimethylammonium chloride was used instead of 0.1 part of polyvinylbenzyltrimethylammonium chloride. An electrostatic recording material was obtained in the same manner.

Comparative Example 3 In the formation of the protective layer of Example 1, aluminum salicylate 0.1% was used instead of aluminum salicylate 0.4%.
An electrostatic recording material was obtained in the same manner as in Example 2 except that 005 parts was used.

The six types of electrostatic recording media thus obtained were evaluated as follows, and the results obtained are shown in Table 1. An image was recorded using a Matsushita electrostatic color plotter in an environment of 20 ° C. and 50% RH, and the recording density of the obtained recorded image was measured with a Macbeth densitometer. did. [Criteria for rubbing dirt] ○: No dirt is generated. X: Dirt is generated.

[0022]

[Table 1]

[0023]

As is apparent from the results shown in Table 1, the electrostatic recording material of the present invention is an electrostatic recording material having excellent recording density and less rubbing stains.

Claims (2)

[Claims] 1. An electrostatic recording body comprising a conductive support and a dielectric layer mainly composed of an insulating resin and a pigment, wherein a protective layer containing a charge control agent is provided on the dielectric layer. An electrostatic recording material comprising the charge control agent in an amount of 0.1 to 10% by weight based on the total solid content of the protective layer. 2. The solid coating amount of the protective layer is 0.01 to 1.0 g.
The electrostatic recording material according to claim 1, wherein the electrostatic recording material has a range of / m ² .