JPS5858549A - Electrostatic recording material - Google Patents

Abstract

PURPOSE:To enable solid scanning and to improve printing resistance in a transfer type electrostatic recording material having a surface-roughened dielectric layer on a conductive substrate, by using a dielectric layer contg. a powder of Al2O3 or ZrO2 as a dielectric and a heat hardenable resin. CONSTITUTION:A conductive substrate is prepared by vapor-depositing Pt on a polyester film, on this film a liquid dispersion obtained by dispersing 25pts.wt. Al2O3 powder into 15pts.wt. polyol acrylate, and adding isocyanate to this dispersion is coated, dried, and heat hardened to obtain an electrostatic recording material 1. This has a roughened surface, and >=10<9>ohm.cm, and it can be solid- scanned. Image signal voltage is applied to it with styli 2 to form an electrostatic latent image 3. This is developed with toner in a developing device 4 to obtain a toner image 5, and this is transferred to a transfer paper 7 using plain paper with a transfer corona charger 6 to obtain a recorded image 8, thus permitting a printing resistance as high as 50,000 cycles using 130V recording potential.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer-type electrostatic recording medium, and particularly relates to a transfer-type electrostatic recording medium that can form static electricity on the surface of the recording medium by applying image signals from multi-needle electrodes. Regarding recording bodies.

A recorded image can be obtained by developing this image with toner and then transferring the toner image onto plain paper, and the recording medium can be used repeatedly by removing the charge.

The recording method using a non-innocent printer is as follows:
Electrostatic recording methods, thermal recording methods, inkjet recording methods, laser printing recording methods, etc. are known. Although the thermal recording method is capable of solid-state scanning, the printing speed is slow, it requires special recording paper, and it cannot record on plain paper. Although the inkjet recording method can record on plain paper,
(1) Since ink liquid is used, reliability is low due to instability of liquid properties due to thermal fluctuations and nozzle clogging due to drying.
(2) It is difficult to miniaturize the print head, making it difficult to print in multiple formats and solid-state scanning is difficult. (3) Since the image is a dot image made of ink droplets, ultra-high speed is impossible due to the viscosity limit. (4)
Since dyes are used as the ink pigments, there are drawbacks such as easy fading.

Although the laser printing recording method allows plain paper FFI recording, (1) it uses a photoreceptor, so it has a limited lifespan;

(2) It is difficult to use multiple laser oscillators, making it difficult to operate the solid state; and (3) The scanning system (scanner unit) is expensive.

Therefore, the electrostatic recording method, which has the fastest printing speed of one dot, is easily multiplied, and can perform solid-state scanning, is attracting attention.In particular, from the pursuit of reducing recording paper costs and improving copy quality due to the increase in reception volume, There is a strong demand for a transfer type electrostatic recording printer capable of recording on plain paper, and the recording medium of the present invention can be used in this printer.

An electrostatic latent image is formed by causing a discharge between the recording electrode and the dielectric layer of the recording medium, and therefore a voltage higher than the discharge starting voltage curve of PASSION must be applied to the recording electrode. If the gap between the recording medium and the recording electrode is too small, the voltage required to start a discharge will suddenly rise; if the gap is too large, not only will resolution deteriorate, but the starting voltage will rise and a discharge will occur. It becomes difficult to do. As described above, when it comes to discharge, it is very important to control the air gap, but it is extremely difficult to control this on the μm order.

Therefore, by making the surface of the I-electrode layer uneven and bringing the recording electrode into contact with it, a gap between the recording body and the recording body is secured under the recording electrode at a portion t where discharge is most likely to occur, and an electrostatic latent image is formed. things are being done. However, conventional recording media have an insufficient printing durability of only a few hundred sheets, and also suffer from discharge! 2! Gap control was still not sufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a perforated recording material with excellent printing durability that can be used in a plain paper non-impact printer capable of solid-state scanning. The present invention also provides a discharge gap side-
An object of the present invention is to provide an electrostatic recording material that has good properties and can easily be made to have a high resolution.

That is, the electrostatic recording material of the present invention is a transfer type electrostatic recording material having an Im electrical layer with an uneven surface on a conductive support, in which a thermosetting resin is used as a binder resin in the dielectric layer, and The aluminum oxide powder is characterized by using zirconium oxide powder as the surface roughening agent.

Hereinafter, the electrostatic recording medium of the present invention will be explained in more detail.

As a conductive support, Pt or Au is used on a plastic film that collects light using polyester.

Aj! g A material provided with a conductive layer such as Xn1O@ or a conductive layer made of carzene-dispersed resin (polyester, etc.), a metal plate, etc. are used.

Nicum powder or zirconium oxide is deposited on aluminum oxide.
It is dispersed in A resin to give unevenness to the surface of the dielectric layer, and both have high hardness and large electrical resistance. Aluminum oxide has a *[(Mohs) value of 9 and a volume resistance of lO
1i more than Ω scratches! Indicates Lft. Furthermore, zirconium oxide has a hardness of 7 and a volume resistivity of 10@Ω or more.

Since the thermosetting resin used as the binder has a three-dimensional network structure, it is possible to form a durable, hard, and high-resistance dielectric layer. 1+, they generally have excellent adhesive strength, and from this point of view, particularly preferred are modified urethane resins such as acrylic modified, modified silicone resins such as acrylic or alkyd modified, modified epoxy resins, and urea-melane resins. These resins are powder (＾1vOs *
Zr0t), conductive material (Cardy dispersion resin, P
t, Au, kl, Ag, etc.), exhibits strong adhesion to supports, etc. These resins had a residual rate of 80% or more in platinum-like, aluminum plates, aluminum oxide plates, and polyester films using a cross-cut test method.

According to the present invention, a dielectric layer with high resistance and large surface hardness can be obtained by combining a specific powder and a binder. It is preferable that the volume resistivity is 10°Ω or more, more preferably 1OQ or more. From the viewpoint of printing durability, the dielectric layer has passed the lead wire scratch test (JI8-540).
0) and preferably has a surface hardness of H or higher, more preferably 3H or higher.

In order to produce the electrostatic recording material of the present invention, a dispersion containing powder and a binder may be applied onto a conductive support/body, and then dried and hardened to form a dielectric layer with an uneven surface. At this time, the degree of surface unevenness can be adjusted by adjusting the particle size of the dispersed powder in the dispersion, the powder/resin ratio, the viscosity of the dispersion, the solvent used, etc.
In order to obtain good discharge gap control, it is preferable that the powder serving as the surface unevenness forming agent has an average particle size of 1 to 20 μm and a square root of the average dispersion σ of 10 μm or less. Moreover, the volume fraction of the powder in the dielectric layer is preferably 5 to 50 volumes. Good discharge gap control makes it easier to achieve high resolution with 8 lines/wx
You can get more than that.

Furthermore, if a 2 g mold is used as the thermosetting resin, the coating operation is easy and the dielectric layer can be formed stably. For example, in the case where a polyurethane resin is used, only a polyol can be present in the process of dispersing powder such as aluminum oxide in a coating liquid. No matter how much mechanical stress is applied to the polyol during the dispersion process, the polyol itself remains stable.
It can be sufficiently dispersed and a coating liquid can be stably prepared. After dispersion is complete, curing of the resin begins by adding incyanate liquid.

In order to actually obtain a recorded image using the electrostatic recording material of the present invention, it is sufficient to form an electrostatic recording medium and then develop and transfer it in the same manner as in the conventional electrophotographic method, for example, as shown in FIG. It depends on the process.

An image signal voltage is applied to an endless belt-shaped electrostatic recording medium 1 through a stylus 2 to form a static electrostatic recording medium 3. This latent image 3 is transferred to a developing member 4 and developed to form a toner image 5.
Then transfer paper 7 is transferred by transfer corona charger 6.
A recorded image 8' is obtained by transferring the recorded image to . Even after the transfer process, the toner adhering to the electrostatic recording medium l is removed by a cleaning roller 9, and then removed by a static elimination roller 10. The electrostatic recording medium is neutralized by the AC corona charger 11 and reused.

The shape of the electrostatic recording medium is not particularly limited, but from the viewpoint of repeated use, a flexible endless belt shape, a rigid drum shape, etc. are common.

According to the present invention, by using aluminum oxide and zirconium oxide as surface unevenness forming agents of the dielectric layer in combination with a thermosetting resin as a binder, the surface hardness and adhesiveness are improved, and it is possible to print more than 50,000 sheets. An electrostatic recording medium having printing durability of

Example 1 Platinum was deposited on a polyester film with a thickness of 1001 ira, and a conductive layer with a surface electrical resistance of 8XIU''Ω/hole was made of the conductive film.

Aluminum oxide powder (Showa Light Metal: A-42° average particle size 5.02μ skin, σ-2.02μ) 25 parts by weight Acrylic polyol (Hitachi Chemical; Hitaloid 3088) 15-weight US
10 parts by weight of methyl ethyl ketone The above composition was dispersed in 2-lumyl for 1 hour, and then 5 parts by weight of incyanate (Sumidur L-75, produced by Sumitomo Chemical Co., Ltd.) were mixed and thoroughly stirred.

This dispersion was applied onto a conductive film by a blade coating method, cured at 90°C for 30 minutes, and the thickness was 15 μm.
An electrostatic recording material having a dielectric layer of A JIS lead wire hit test was conducted and the result was 6H.

Next, with two single-sided control type multi-stylus units with 8 strands/l dew, the stylus applied voltage was -3501y lt, and the segment voltage was +3.
When a latent image was recorded for 4 days at 50 delts, the surface recording potential was 1130 delts. Measurement of surface potential was controlled by a vibrating capacitance type surface potentiometer manufactured by Kawaguchi Electric.

Next, a printing durability test of 50,000 sheets was conducted using the process apparatus shown in Fig. M1. The results are shown in FIG. 2 together with the results of Example 2.

Example 2 Aluminum oxide powder <Wd Wawakai Metal A-31° average particle size 9.46/1lfi, F-5,941On) on the same conductive film as Example 1
10 parts by weight Acrylic polyol (Hitachi Chemical; Hitaloid 3088) 15 parts by weight Methyl ethyl ketone 10 parts by weight The above composition was dispersed in a 2-l building for 1 hour, and then incyanate (Bavaria; Desmodur L-60) 4 parts by weight 1fls was mixed and stirred.

Using this dispersion, a recording medium was prepared in the same manner as in Example 1,
After nine images were recorded, the surface recording potential was 120 cels. The JIS pencil scratch test was 5H.

Next, printing durability was evaluated in the same manner as in Example 1, and the results are shown in Figure 1g2.

Example 3 A polyester resin (Toyobo; Pylon 200) was dissolved in detrahydrofuran, and 4-ton amount of carmen black was added and dispersed and coated on a 100-μm polyester film to form a 10Ω 7′ conductive film. Obtained.

Zirconium oxide powder (manufactured by Shinano Seiki Co., Ltd., average particle size 6.7
μm, σ body 3.9 μl 1 l) 30 parts by weight urea) t Mitsuki jk (virtual Nhffti oil; RAP-
1s) 2s kill! Disperse 1 part of the above composition in B methyl ethyl ketone to: for 2 hours using a Zeel mill to obtain a dispersion for coating, and apply this dispersion onto a conductive film by a blade coating method,
It was dried and cured at 100 DEG C. for 30 minutes to obtain an electrostatic recording material having a dielectric I- thickness of 15 .mu.m and having six concavo-convex patterns. JIS
When I did the pencil hit test, it was BH. Next, an image was recorded in the same manner as in Example 1, and the surface recording potential was 11,401 years. Next, a printing durability test of 70,000 sheets was conducted in the same manner as in Example 1. The results are shown in FIG. 3 together with the results of Example 4.

Example 4 Carmen dispersion was applied onto a 100μ wing polyester film in the same manner as in Example 3 to obtain a conductive film of 2×10′Ω/hole.

Zirconium oxide powder (made by Shinano Refining Co., Ltd., average particle size 8.3 μm, σ-4.2 μm) 2
0 parts by weight Acrylic polyol (Hitachi Chemical; Hitaloid 3088) 15 parts by weight Methyl ethyl ketone 1031 parts The above composition was dispersed for 2 hours at g-/l/l, and then incyanate (Sumidur Chemical; Sumidur L-75) ) 5 parts by weight were mixed and thoroughly stirred.

This dispersion was applied onto a conductive film in the same manner as in Example 3 to form a dielectric layer with a thickness of 19 μm to obtain an electrostatic recording material. The JIS pencil scratch test was 6H. In the same manner as in Example 1, i! When I recorded the image, the surface potential recorded was -140 melt. Next, a 70,000-sheet printing test was conducted in the same manner as in Example 1.

The results are shown in Figure 3.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the process applied to the electrostatic recording medium of the present invention. FIGS. 2 and 3 are graphs showing the printing durability of electrostatic recording materials. 1... Electrostatic recording medium 2... Stylus 4...
・Developing unit 7... Transfer unit 9...
Cleaning roller 11 AC charger WJI Figure 2 Figure 3

Claims (1)

[Claims] 1. In a transfer type electrostatic recording material having a cast layer with an uneven surface on a conductive support, the VIT layer contains aluminum oxide powder or zirconium oxide powder and a thermosetting resin. f: Characteristic electrostatic recording material.