JPH0715579B2 - Electrostatic recording film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an electrostatic recording body for directly converting an electric signal into an electrostatic latent image. In particular, the present invention relates to an electrostatic recording material having a clear image and no fog.

[Prior art]

There is known an electrostatic recording film in which an insulating film, a conductive layer and a dielectric layer are laminated in this order.

In the electrostatic recording method, a recording voltage is applied to a multi-pin electrode head (hereinafter abbreviated as pin electrode), and an air discharge is generated in a minute gap (hereinafter abbreviated as a gear gap) between the pin electrode and the dielectric layer of the electrostatic recording film. Then, an electrostatic latent image is formed on the surface of the dielectric layer, and then the electrostatic latent image is developed with toner to form a visible image. In order to obtain a clear image in this way, it is necessary to control the gear gap within an appropriate range from the Passenger curve. For this reason, insulating particles are added to bring the electrostatic layer with appropriate irregularities into contact with the pin electrode. The most commonly used method is to control the gear appropriately. It is known that in such an electrostatic recording film, a clear image cannot be obtained unless insulating particles are added to the dielectric layer, while "fogging" occurs when the ground of the conductive layer is incomplete.

In the conventional electrostatic recording paper, it is possible to ground from the paper surface side of the conductive paper, but in the electrostatic recording film using the insulating film, it is not possible to ground from the film surface side of the insulating film. For this reason, some parts (generally the ends) of the conductive layer are exposed, and some of the exposed parts are coated with a conductive paint such as carbon paint to form a ground electrode. In addition, it takes time and effort to expose the conductive layer, and the manufacturing process is increased due to the coating of the conductive coating, resulting in poor productivity. For this reason, it has been proposed to disperse conductive powder in the dielectric layer and to make the conductive powder in contact with each other by pressurization above a certain pressure so as to have conductivity (Japanese Patent Publication No. 57-12144). Issue).

Such an electrostatic recording film has a pin electrode (pressing force of 50 to 10
(0g / cm ² ), the conductive layer in the dielectric is contacted by pressing the conductive roll (pressing force 500 to 5000g / cm ² ) before development to bring the conductive layer into contact with the ground electrode. It is explained that the fog can be eliminated by keeping it at.

Although such an electrostatic recording film surely eliminates fogging, in order to bring the conductive powder into contact by pressing,
It is necessary to add a large amount of conductive powder, and there is a new defect that pixels are linearly removed in the direction parallel to the recording electrodes (hereinafter abbreviated as “line omission”). Hereinafter, there is a problem such as an increase in "Gomacio").

[Problems to be solved by the invention]

An object of the present invention is to solve the above-mentioned drawbacks and to provide an electrostatic recording film which can obtain a clear image with less fog, line omission and gommacio.

[Means for solving problems]

The present invention has the following constitution in order to achieve the above object. That is, in an electrostatic recording film in which an insulating film, a conductive layer and a dielectric layer are laminated in this order, the induction layer is composed of at least a polymer binder, insulating particles and conductive powder, and the polymer binder The weight ratio of adhesive and conductive powder is
The electrostatic recording film is characterized in that it is 100 / 0.1 to 100/10.

The dielectric layer of the present invention comprises a polymer binder, insulating particles and a conductive powder, and the weight ratio of the polymer binder and the conductive powder is 100 / 0.1 to 100/10.

The polymer binder used in the present invention is made of a thermoplastic resin or a curable resin, and various resins usually used in the dielectric layer of such an electrostatic recording film can be used. Examples of the thermoplastic resin include polyester, polyesteramide, polyvinyl acetal, polyvinyl chloride, poly (meth) acrylic acid ester, polyamide, polyurethane,
Examples thereof include polycarbonate, polystyrene, polymethylpentene, alkyd resin, polyamideimide, silicon resin, fluorine resin and the like, and copolymers and blends thereof. As the curable resin which is cured by heat, light, oxygen, etc., for example, a phenol resin, a melamine resin, an epoxy resin, a crosslinked organosilicon compound, a poly (meth) acrylic acid ester copolymer containing a reactive monomer can be used. Examples include those obtained by adding a crosslinking agent and crosslinking. These polymer binders preferably have a volume resistivity of 10 ¹² Ω · cm or more. If it is smaller than this, the printing density becomes low, which is not preferable.

The electrically conductive powder preferably has a volume resistivity of 10 ⁻⁶ to 10 ⁴ Ω · cm, and a generally known electrically conductive powder is used. Such preferred compositions include Al, Cr, Cd, Ti, Fe, Cu, I
Metals such as n, Ni, Pd, Pt, Rh, Ag, Ru, W, Sn, Zr, Ir, stainless, alloy, alloy such as Ni-Cr, indium oxide, tin oxide, zinc oxide, titanium oxide, Examples thereof include metal oxides such as vanadium oxide, ruthenium oxide, tantalum oxide, and metal compounds such as copper iodide, but are not limited thereto. These may be used alone or in combination in the form of a mixture of two or more kinds. These conductive powders preferably have a small average particle size, preferably 0.01 to 10 μm, more preferably 0.1 to 5 μm. If it is smaller than this, the dispersibility is deteriorated, while if it is larger than this, homogeneity of image quality cannot be obtained, which is not preferable.

The volume resistivity is preferably 10 ⁻⁶ to 10 ⁴ Ω · cm. If it is larger than this, the effect for eliminating fogging is small and it is not preferable.

The weight ratio of polymer binder to conductive powder is 100 / 0.1 to 100/10.
It is necessary to be. More preferably 100 / 0.3-1
It is desirable that it is 00/5. If it is less than this, the effect of eliminating the fog is small, and if it is more than this, line breakage and gomasio increase, which is not preferable.

The insulating particles have a volume resistivity of 10 ⁸ Ω · cm or more,
More preferably, commonly known inorganic particles and / or organic particles having a density of 10 ¹⁰ Ω · cm or more are used. Examples of such inorganic particles include metal oxides such as silicon oxide, titanium oxide, alumina, lead oxide and zirconium oxide, salts such as calcium carbonate and barium titanate, and examples of organic particles include styrene-divinylbenzene. Copolymer, melamine resin, epoxy resin, phenol resin,
It is appropriately selected from fluorine resin and the like. These insulating particles may be used alone or as a mixture of two or more kinds. The average particle size of the above insulating particles is generally 0.1 to 2 due to the stability of discharge.
It is preferable to appropriately select in the range of 0 μm. The weight ratio of the polymer binder and the insulating particles is preferably 100 / 0.5 to 100/150. If it is less than this, the stability of the discharge is poor, and if it is more than this, the film strength of the dielectric layer becomes weak, which is not preferable.

The thickness of the dielectric layer is preferably 1 to 20 μm. If it is thinner than this, the surface potential is low, and if it is thicker than this, the resolution deteriorates, which is not preferable.

The dielectric layer may be laminated in multiple layers other than a single layer,
Further, an intermediate layer such as an adhesive layer may be provided between the conductive layer and the dielectric layer.

In the dielectric layer of the present invention, a plasticizer, an adhesion promoter, a stabilizer, an antioxidant, an ultraviolet absorber, an optional agent may be added, if necessary, within a range that does not impair the characteristics of the electrostatic recording film of the present invention.
A lubricant or the like may be added.

In the present invention, an insulating protective layer containing no conductive powder may be provided on the dielectric layer. The thickness of the protective layer is preferably thin, and is preferably 5 μm or less, more preferably 1 μm or less.

As a method of adding the dielectric layer, a known method is effectively used. For example, it is appropriately selected from brush coating, dip coating, knife coating, roll coating, spray coating, flow coating, spin coating (spinner, whaler, etc.).

The insulating film used in the present invention is a film made of an insulating thermoplastic resin or thermosetting resin having a generally known volume resistivity of 10 ¹² Ω · cm or more. Resins for this film include polyester, polyolefin, polyamide, polyesteramide, polyether,
Polyimide, polyamide imide, polystyrene, polycarbonate, poly-p-phenylene sulfide, polyether ester, polyvinyl chloride, poly (meth) acrylic acid ester and the like are preferable.

Furthermore, these copolymers, blends, and further crosslinked products can be used. Further, it is preferable that these resins are stretch-processed because the mechanical strength, dimensional stability, thermal properties and optical properties are improved. Among these, polyester is preferably used. Here, the polyester is a polyester having an aromatic dicarboxylic acid as a main acid component and an alkylene glycol as a main glycol component.

Specific examples of the aromatic dicarboxylic acid include terephthalic acid,
Isophthalic acid, naphthalene dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid, α, β-bis (2- Chlorphenoxy)
Examples thereof include ethane-4,4'-dicarboxylic acid. Of these, terephthalic acid is particularly desirable.

As specific examples of the alkylene glycol, ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, and hexylene glycol are desirable.

Of course, these polyesters may be homopolyesters or copolyesters (copolymerized polyesters), and examples of components to be copolymerized include diethylene glycol, propylene glycol, neopentyl glycol, polyalkylene glycol, p- Diol components such as xylylene glycol, 1,4-cyclohexanedimethanol, 5-sodium sulforesorcin, adipic acid, sebacic acid, phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 5-sodium sulfoisophthalic acid, etc. Examples thereof include dicarboxylic acid components, polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid, and oxycarboxylic acid components such as p-oxyethoxybenzoic acid.

The thickness of the plastic film is 10 μm to 250 μm.
Is preferred. More preferably 15 μm to 150
μm is desirable. If it is thinner than this, the mechanical strength of the film is insufficient, and if it is thicker than this, the film transfer property deteriorates, which is not preferable.

These plastic films may be subjected to known surface treatments such as corona discharge treatment, plasma discharge treatment and anchor coating, if necessary, in order to improve the adhesiveness.

Further, the insulating film preferably has a coefficient of static friction of 2.0 or less, more preferably 1.0 or less, in order to prevent the occurrence of scratches during running.

As the conductive layer of the present invention, a commonly known one is used. The surface electric resistance is preferably 10 ⁴ to 10 ⁹ Ω / port. Examples of the conductive layer include (1) a layer made of a metal or metal oxide having an electron conductivity, (2) a layer coated with an ion conductive polymer electrolyte, (3) a conductive powder and a polymer binder. Or coated with a layer composed of a polymer electrolyte.

In this case, as the conductive powder, those used for the dielectric layer can be used, and as the polymer electrolyte, quaternary ammonium salts, sulfonates, polyalcohols and the like can be mentioned, but not limited thereto. These may be used alone or in combination of two or more. Such a conductive layer is formed by plating, vacuum deposition, chemical vapor deposition, sputtering, coating or the like. Among these, the island-shaped discontinuous metal film made of a material mainly composed of at least one metal selected from the group consisting of Rh, Pd, Ir, Pt, and Ru has a uniform surface electric resistance and humidity. Is particularly preferable from the standpoint of stability against. The island-shaped discontinuous metal film is a film in which metal particles are scattered on the insulating film, and its average size is particularly in the range of 10 ^-5 to 10 ^-2 square micron. preferable. The density of the island-shaped discontinuous metal film is preferably 15 to 50% in terms of area fraction.

A laminate of the above insulating film and a conductive layer is referred to as a conductive film.

〔The invention's effect〕

The present invention applies a specific dielectric layer to an electrostatic recording film in which an insulating film, a conductive layer, and a dielectric layer are laminated in this order, so that there is no fogging in the image, there are few line dropouts and gommacio, and a clear image is obtained. I was able to obtain.

As described above, since the electrostatic recording film of the present invention has excellent characteristics, it can be used not only as an electrostatic recording film for hard copy but also for electrostatic recording printers / plotters and facsimiles, and it can be repeatedly used. As an electrostatic recording film for the master film used, it is a transfer master for copiers, facsimile receivers, printers and electrophotographic process of electrostatic latent image transfer method (TESI method).
It is also useful as a recording body for holding a transferred electrostatic latent image, and as a recording film for a display by an electrostatic recording method.

[Method of measuring characteristics]

(1) Surface electric resistance A conductive film is cut into a width of 30 mm, and two parallel lines that are orthogonal to the cutting line and have an interval of 30 mm are assumed. Right and left except the section sandwiched by the two lines. Conductive carbon paint is applied to each of these and used as electrodes. The electrical resistance between these electrodes is measured by Keithley Electrometer (Type 610
C) was used and the measurement was performed at 20 ° C-65% RH. The unit is Ω / mouth. The surface electric resistance of the electrostatic recording film was also measured according to this.

(2) Image quality An electrostatic latent image is formed on the surface of the electrostatic recording film by a multi-pin electrode head, and then the electrostatic latent image is visualized by a wet toner developing machine and then dried to obtain a hard copy image. It was Here, between the head and the developing machine, a roll or the like that contacts the dielectric layer surface and applies a pressing force was not used at all. Relative humidity (hereinafter RH) is 20%, 60% and 80%
Was carried out under the respective conditions.

(B) Fogging The margin of image recording was measured as the reflection density with a Sakura Micro Densitometer (Model PDM-5).
The above items were regarded as defective.

(B) Line breaks (line breaks) 10 (same direction as head) x 100 (vertical direction to head) dots were printed, and the number of line breaks (line breaks) was measured. An average value of n-5 was 5 or less, good, 6 to 15 were good, and 16 or more was bad.

(C) Domasio 125 μm dots were printed at a rate of 8 dots / mm, and the number of gomassio per 100 mm was measured. 40 or less were considered as good, 41 to 150 were evaluated as good, and 151 or more were evaluated as bad.

〔Example〕

Hereinafter, the present invention will be described with reference to examples. The present invention is not limited to these. In addition, all compounding parts in the examples are parts by weight.

Examples 1 to 5 Pd was sputtered onto a biaxially stretched polyethylene terephthalate film (“Lumirror” manufactured by Toray Industries, Inc.) having a thickness of 75 μm to obtain a conductive film having a surface electric resistance of 7 × 10 ⁶ Ω / port. Obtained. A dielectric layer having the composition shown in Table 1 was coated on this conductive film (thickness after drying 3 g / m ² ) to obtain an electrostatic recording film of the present invention (Examples 1 to 5). . These various properties are summarized in Table 1.

Comparative Examples 1 to 3 Comparative Examples 1 to 3 were obtained in the same manner as in Example 1 except that the dielectric layer composition was the composition shown in Table 1.

From Table 1, the electrostatic recording film Examples 1 to 5) of the present invention have no fog regardless of relative humidity as compared with Comparative Examples 1 to 3,
Moreover, it is clear that it shows excellent image characteristics with few line-throughs and gomassio. In addition, Examples 1 to 5 have good transparency (SPHERE METHOD METER (TYPE SEP-
H-S) was used to measure the total light transmittance at 550 nm. All were greater than 75%. ), It could be used as a transparent electrostatic recording film for electrostatic plotters.

Example 6 Pt was sputtered onto a biaxially stretched polyethylene terephthalate film (“Lumirror” manufactured by Toray Industries, Inc.) having a thickness of 100 μm to obtain a conductive film having a surface electric resistance of 1 × 10 ⁷ Ω / port. . A self-crosslinking acrylic emulsion was coated on this conductive film so that the thickness after drying was 0.5 μm to form an adhesive layer, and then a polyester resin (“Byron” manufactured by Toyobo Co., Ltd.) / Alumina / Conductive zinc oxide (100 Ω · cm) = 100/20/1 coated with a dielectric layer solution (solvent: tetrahydrofuran) (total weight of adhesive layer and dielectric layer after drying is 8 g / m ² ), An electrostatic recording film of the present invention (Example 6) was obtained. The alumina used had a Mohs hardness of 9.

These properties are summarized in Table 1. From Table 1, it is clear that the electrostatic recording film of the present invention (Example 6) has no fog, few line dropouts and gomasio, and exhibits excellent image characteristics. Also, the toner image was not fixed as it was, but was transferred to plain paper and then fixed to obtain a hard copy, while the electrostatic film was discharged and the residual toner was cleaned and repeatedly used. In this case, the hard copy after repeating 10,000 times had no fog and showed excellent image characteristics with less line breaks and gomassio like the first time. From this, it is apparent that the electrostatic recording film of the present invention is excellent as a master film.

Examples 7 and 8 An electrostatic recording film of the present invention was prepared by coating a dielectric layer having the composition shown in Table 2 on the conductive film of Example 1 (Example 7,
8) got. These properties are summarized in Table 2. All showed excellent image characteristics.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP 54-159231 (JP, A) JP 55-81349 (JP, A) JP 61-144656 (JP, A) JP 61- 144654 (JP, A)

Claims (1)

[Claims] 1. An electrostatic recording film comprising an insulating film, a conductive layer and a dielectric layer, which are laminated in this order, wherein the dielectric layer comprises at least a polymer binder, insulating particles and a conductive powder. The weight ratio of polymer binder and conductive powder is 10
An electrostatic recording film characterized by being 0 / 0.1 to 100/10.