JPS5961836A - Electrostatic recording medium - Google Patents

Abstract

PURPOSE:To obtain an electrostatic recording medium with which an easily readable image having high contrast is obtd. by laminating successively a conductive layer and a dielectric layer on a substrate, and forming at least one layer thereof so as to have specific whiteness. CONSTITUTION:A base material film (A) consisting of an org. high polymer material having an insulation characteristic, a conductive layer (B) having 10<4>- 10<8>OMEGA/? surface resistivity, and a dielectric layer (C) are laminated in this order, and at least one layer of these three layers is formed to have >=30 Hunter whiteness. The film (A) which is subjected to stretching is more preferable as it has a better mechanical property, thermal property, optical property, dimensional stability, etc. The desirable compsn. for forming the layer (B) is metal, metallic compd., inorg. conductive pigment, high polymer electrolyte, etc., which may be used alone or in combination of >=2 kinds. A thermoplastic resin or thermosetting resin is used for the dielectric layer (C).

Description

[Detailed description of the invention] The present invention relates to an electrostatic recording medium.

Conventionally, in the electrostatic recording method that records on plain paper, an electrostatic latent image is recorded on a dielectric layer that is a latent image recording medium, toner is attached to this latent image area to make it visible, and this toner image is normally A process is used to transfer it to paper.

In recent years, with the development of various processes based on electrostatic recording methods, the visible image of the toner formed on the electrostatic recording medium is checked in advance before being transferred to plain paper, and if it is not necessary to transfer it, it is immediately removed. A method of erasing the image and transferring it only when necessary has also come to be adopted. For example, a reader printer is one such example.

However, when a visible toner image is formed on a conventional electrostatic recording medium, it is difficult to obtain a high-contrast image before being transferred to plain paper, and it is almost impossible to read the visible toner image directly. It was impossible.

Therefore, the inventors of the present invention have conducted intensive studies to develop an electrostatic recording material that can provide a high-contrast and easy-to-read toner visible image on an electrostatic recording material, and as a result, they have arrived at the present invention, which is highly effective. did.

That is, in the present invention, a base film (A) made of an insulating organic polymer, a conductive layer (B) and a dielectric layer (C) each having a surface resistance value of 10' to 10'' Ω/hole, (A) / (B) /
Layer (C) in order and force these (A), (B),
The whiteness of at least one of the layers (C) is 7.
The object of the present invention is to provide an electrostatic recording medium in which the number of particles is 0 or more.

The insulating organic polymer film in the layer (A) constituting the electrostatic recording medium of the present invention is a film or sheet made of a thermoplastic resin. Preferred examples include polyesters such as polyethylene terephthalate, polybutylene lenticulate, and polyethylene-2,6-naphthalene dicarboxylate; polyolefins such as polyethylene and polypropylene; so-called nylon-6 and nylon-6;
Polyamides such as No. 12, polyimides having five-membered ring imide bonds in the polymer main chain, cellulose derivatives such as cellulose esters, polyethylene, polycarbonates, acrylic ester copolymers, methacrylic ester copolymers, polyvinyl chloride, polyethers , polyester ether, polyester amide, etc. These may be used alone, or as a blend or copolymer of two or more of them.

Films made of these insulating organic polymers are preferred because mechanical properties, thermal properties, optical properties, dimensional stability, etc. are improved when measured by a stretching force meter.

The conductive layer (B) has a surface resistance value of 10 4 to 10 8 Ω/hole.

Preferred compositions for forming the conductive layer (B) include A1,
Cr, Cd, Ti, F's, Cu, In,
Ni, Pd, Pt%Rh.

Examples include metals and/or metal compounds such as Ag, Sn, W, and Zn, as well as inorganic conductive pigments and polymer electrolytes such as quaternary ammonium salts, sulfonates, and polyalcohols.

These may be used alone or in combination of two or more.

The conductive layer (B) can be formed by plating, vacuum deposition, chemical vapor deposition, or snow (
Those formed by vine ring, coating, lamination, etc. are preferably used.

Thermoplastic resin or thermosetting resin is used for the dielectric layer (C). Preferred compositions constituting the dielectric layer (C) include, for example, polyester, polyether, polycarbonate, polyamide, polyurethane, polyimide having a five-membered ring imide structure in the polymer main chain, acrylic ester copolymer, polystyrene-butadiene. Examples include copolymers, polyvinyl acecool, chlorinated polyolefins, ethylene-vinyl acetate copolymers, alkyd resins, xylene resins, ketone resins, epoxy resins, and organosilicon compounds. These may be used alone or in a mixed system of two or more.

In the present invention, the above-mentioned (A), (B) and (C)
At least one of the layers needs to have a Hunter whiteness of 30 or more, thereby obtaining an electrostatic recording material with a Hunter whiteness of 30 or more.

Appropriate means can be used to increase the Hunter whiteness to 30 or more. (A), Hunter whiteness is 3
In order to achieve a refractive index of 0 or more, organic and/or inorganic particles may be blended with the above-mentioned insulating polymer, or an organic or By adding or blending an inorganic material or a gas containing air, by matting any surface of the insulating organic polymer film, or by adding or blending an inorganic material or a gas containing air, or by adding or blending an inorganic material or a gas containing air. Methods such as coating with molecular materials or coloring with colorants are adopted.

In order to produce a conductive layer (B) with a surface resistance value of 104 to 108 Ω/mouth and a Hunter whiteness of 30 or more, a conductive powder made of the metal, metal compound, metal oxide, etc., and an organic resin are used in combination. It is preferable to do so. At this time, it is also preferable to further add a coloring agent. Here, as the organic resin, a thermoplastic resin or a thermosetting resin, which is usually used as an organic binder, is used.

For example, polyester, polyether, polycarbonate, polyamide, polyurethane, acrylic ester copolymer, methacrylic ester copolymer, polystyrene-butadiene copolymer, polyvinyl acetal, chlorinated polyolefin, ethylene-vinyl acetate copolymer, polyester Thermoplastics such as vinyl acetate, polyvinyl chloride, vinyl acetate-vinyl chloride copolymer, vinyl acetate-vinyl chloride-maleic anhydride copolymer, polyurethane, cellulose derivatives, silicone resin, alkyd resin, ketone resin, xylene resin, etc. These include thermosetting resins such as resins, epoxy resins, unsaturated polyesters, and polyimides, as well as resins obtained by adding a curing agent to thermoplastic resins having functional groups such as hydroxyl groups, carboxyl groups, and amino groups. These may be used alone, in a mixed system of two or more, or in a copolymerized system. Although the size of the conductive powder described above depends on the thickness of (B), it is preferably smaller than the thickness of (B), and preferably has an average particle size of 20 μm or less, particularly 5 μm or less. In order to make the Hunter whiteness of (C) 30 or more, organic and/or inorganic particles may be blended with the thermoplastic resin or thermosetting resin constituting (C), or organic or Adding or blending an inorganic material or a gas containing air, matting the surface of the dielectric layer (C), or coating the dielectric layer (C) with a polymeric material containing components with different refractive indexes. Alternatively, methods such as coloring with a coloring agent may be adopted.

In the present invention, for the purpose of roughening the surface of the electrostatic recording medium as necessary, the (C) layer and/or the (B) layer in the case of a conductive powder and an organic resin are inorganic and/or organic. particles may be added.

In the present invention, (B
) The thickness of the layer is preferably from 1μ to 100μ, in particular from 2μ to 20μ. (C) Layer thickness is from 1μ to 100μ
It is desirable that μ. Further, a protective layer may be provided on the layer (C).

The odor of the present invention (B) is composed of conductive powder and organic resin.
), and (C) can be added using conventional methods such as film attachment, brush coating, dip coating, knife coating, roll coating, spray coating, flow coating, and rotary coating (spinner, whey 2-, etc.). Application methods are readily available.

In order to improve the flow and smoothness of the coating film during application, a plasticizer may be blended into the composition of layer (C) of the present invention, and an adhesion promoter may be added as necessary. It is also permitted to use additives such as stabilizers, antioxidants, ultraviolet absorbers, lubricants, antifoaming agents, and colorants.

In the present invention, if necessary, (A)/
Other polymers may be applied between (B) and (B)/(C) for the purpose of improving adhesiveness, but the thickness is 20%.
It is preferably 5 μ or less, particularly 5 μ or less. In the present invention,
If necessary, it is also possible to provide an antistatic layer on the back surface of the electrostatic recording medium.

The electrostatic recording material of the present invention thus obtained has a dielectric layer (C)
When an electrostatic latent image is formed on the surface and toner is electrostatically attached to this latent image to make it visible, the contrast is high.
An image that is easy to read is obtained. As a result, it can be used very conveniently as a reader printer, and can also be used in ordinary electrostatic recording medium applications such as facsimiles and printers.

The present invention will be explained below based on Examples. However, the present invention is not limited to this example.

Example 1 A base film having a thickness of 100 μm was obtained by biaxially stretching polyethylene terephthalate to which a white pigment was added. Next, on one side of this base film, PT was applied with a surface resistance value of 106Ω.
A conductive film was obtained by sputtering to form a conductive film. On the PTO of this conductive film, a paint prepared by dissolving polyester resin in tetrahydrofuran so that the solid content is 10% by weight is applied with a metering rod so that the thickness after drying is 5 μm, and then dried. electrostatic recording material (1
) was obtained.

Example 2 An organic conductive layer containing polyvinylbenzyl trimethylammonium chloride as a main component was coated on one side of the same base film as in Example 1, and the surface resistance value was 25.
A conductive film having a resistance of 107 Ω/hole at 65% RH was obtained. On the organic conductive layer of this conductive film, after drying, a paint prepared by dispersing and mixing polycarbonate resin and silica in a mixed solvent of monochlorobenzene/dichloroethane = 1/1 so that the solid content is 10.1% by weight, respectively, is applied. It was coated with a metering rod to a thickness of 8 μm and dried to obtain a blank recording material (2) of the present invention.

Example 3 A cross-linked acrylic copolymer and tin-doped zinc oxide were placed on one side of a 100 μm thick base film obtained by biaxially stretching polyethylene terephthalate to which a white pigment was added, each having a solid content of 10.10 μm. A conductive film with a surface resistance value of 107 Ω/mouth after being mixed with tetrahydrofuran and sufficiently dispersed in a proportion of % by weight, dried, applied with a metering rod to a thickness of 10 μm after curing, and dried. I got it. Next, on the conductive layer of this conductive film, a paint made by dispersing and mixing polyester resin and silica in tetrahydrofuran so that the solid content is 10.1% by weight each is metalized so that the thickness after drying is 7 μm. The electrostatic recording material (3) of the present invention was obtained by coating with a stick and drying.

Comparative Example 1 An electrostatic recording material having exactly the same structure as in Example 1 was obtained (Comparative-1) except that biaxially stretched polyethylene terephthalate to which no white pigment was added was used as the base film.

The whiteness, image characteristics, etc. of the electrostatic recording material thus obtained were as shown in Table 1. From this result, it is clear that the electrostatic recording materials (1), (2), and (3) according to the present invention have much clearer visible toner images before transfer than those of (Comparison-1).

Table 1 1) Hunter whiteness is 5 using a Hunter whiteness meter.
Measured at 50 mμ.

2) Manufactured by Fuji Photo Film ■, Fuji standard density piece (13 steps)
It was used.

Claims (1)

[Claims] Base film made of insulating organic polymer, surface resistance is 1
An electrostatic recording material comprising a conductive layer and a dielectric layer laminated in this order and having a non-interwhiteness of at least 30 or more among these three layers.