JPS61144656A - Electrostatic recorder - Google Patents

Abstract

PURPOSE:To improve a corona resistant characteristic and to eliminate the adverse influence of frictional electrostatic charge on a dielectric surface by using a recording medium provided with a mixture composed of inorg. powder having >=10<10>OMEGA.cm volume resistivity, pulverous powder having <10<10>OMEGA.cm volume resistivity and resin for forming film having >=10<12>OMEGA surface resistance as a dielectric layer. CONSTITUTION:The film formed of the mixture composed of (A) the inorg. powder having >=10<10>OMEGA.cm volume resistivity, (B) the conductive powder having <10<10>OMEGA.cm volume resistivity and (C) the resin for forming film having >=10<12>OMEGA surface resistance after film formation is used as the recording medium in a dielectric drum 1 which in the recording medium provided with the dielectric layer 2 as a recording layer on a conductive base material 3. The mixing ratio of the inorg. powder (the component A) and the resin for forming film (the component C) is in a 5-300pts.wt. range the lattery by 100pts.wt. the former.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrostatic recording device, and particularly to a pressure transfer type electrostatic recording device using an electrostatic recording medium that can be used multiple times.

[Prior art]

Conventionally, as a recording medium in an electrostatic recording device, electrostatic recording paper with a conductive layer provided between the recording layer and the base is generally used. A recorded image is obtained by forming an electrostatic latent image, developing it with toner, and fixing it. However, when such electrostatic recording paper is used, it is unavoidable that excess toner adheres to the surface of the recording paper, and it also has drawbacks such as being highly susceptible to the atmosphere (moisture, heat, etc.) during use. This is not a trivial matter; since electrostatic recording paper itself is special compared to plain paper, its use as a consumable item has the drawback of significantly higher running costs. In order to solve these drawbacks, electrostatic recording devices that transfer images onto plain paper have been developed (for example, Japanese Patent Publication No. 46-34077). According to this method, a recording medium is formed in the form of a belt, in which a dielectric layer having a volume resistivity of 100 mm is provided on a biaxially stretched I-lyester base material, and a needle electrode and a dielectric layer are formed using a multi-stylus. The surface of the dielectric material is charged by applying a high voltage between it and the body surface to generate a discharge, and the electrostatic latent image formed is then developed with toner to obtain a powder film, which is then printed on plain paper. Images have been obtained by electrostatic transfer. However, in this method, the toner image is electrostatically transferred to plain paper, so the transfer efficiency is as low as 5 ots, which is disadvantageous in terms of lower image density, cleaning of residual toner, and scattering. Image distortion occurs due to transfer.

On the other hand, a dielectric thin layer is provided on the surface of a conductive rigid cylinder, an electrostatic latent image is formed on the surface of this dielectric thin layer, this latent image is developed with toner, and then transferred (by pressure) onto plain paper. There are known methods for fixing the
In this method, the dielectric thin layer is subjected to rubbing by the paper, so that the surface thereof is polished. Therefore, the point of view to increase the hardness of the dielectric layer is to use anodized aluminum, thermally sprayed At20
．． Inorganic dielectrics such as , glass enamel, and organic dielectrics such as polyamide, polyimide, fluoride, and base resin are used. However, anodized aluminum, thermal sprayed At20.
Inorganic dielectric layers such as glass enamel suffer from a significant decrease in surface resistance due to adhesion of moisture in the atmosphere, making it impossible to obtain good images. Furthermore, organic dielectric layers such as polyamide and polyimide have insufficient abrasion resistance, resulting in problems such as abrasion of the surface during cutting with a cleaner, and sufficient durability cannot be obtained. Particularly when carrying out simultaneous pressure transfer and fixing, friction with the transfer paper is taken into account, making it even more difficult to use an organic recording layer. Furthermore, when these organic recording materials are used for long periods of time, they are oxidized by ozone under high electric fields and their moisture resistance decreases. Polyimide and 4-lyamide resins are weak against impact and are prone to crack-like scratches, which cause peeling.Furthermore, in pressure transfer type resins, the surface energy is large, so the transfer efficiency tends to be as low as 80 or less. 7. Although base resin has good transfer efficiency, it is soft and easily causes scratches.
In the case of the net pressure transfer method, the surface of the dielectric layer contacts the plain paper and the pressure roller 2 under pressure, so that triboelectric charges are induced on the surface of the dielectric layer.

The polarity and amount of the electric charges induced at this time depend on the material of the pressure contact member, for example, the components of the transfer material and the resin component of the pressure roller.
It varies depending on the surface roughness of the pressure contact member, and the temperature and humidity of the usage environment, and is significantly affected. For this reason, if triboelectric charging with a significantly higher potential than the potential of the electrostatic latent image or triboelectrical charging with a polarity opposite to that of the electrostatic latent image occurs, uniform charge removal becomes difficult. In addition, unnecessary triboelectric charging on the dielectric surface promotes the adhesion of discharge products and charged fine particles such as paper dust (f), and furthermore, these adhering substances absorb moisture, resulting in a significant decrease in surface resistance. has a negative effect on the image. Furthermore, if the distribution of triboelectric charges on the surface of the dielectric layer is non-uniform, ion implantation during the formation of electrostatic latent regions may be inhibited, resulting in adverse effects such as blurring and white spots on the image.

In order to eliminate the above disadvantages, it is possible to stabilize triboelectrification by reducing the occurrence of triboelectrification, or by increasing the attenuation rate of the triboelectrostatic potential, by using a dielectric material with a low insulation resistance value. However, if the material has a low resistance value, the surface resistance of the dielectric will also decrease, resulting in a stable electrostatic I! I couldn't use it because I couldn't get it and the image would be distorted.

As mentioned above, it is less susceptible to the effects of moisture in the air, has good transfer efficiency, and satisfies all of the characteristics of abrasion resistance, impact resistance, and ozone resistance at the same time, and also has no negative effects on images due to frictional charging. However, we have not been able to obtain anything that can withstand long-term use.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a recording medium that can be used multiple times and is used in an electrostatic recording device, particularly an electrostatic recording device that uses pressure to transfer a toner image on the surface of a dielectric layer of the recording medium onto plain paper. It is an object of the present invention to provide an electrostatic recording medium that is free from the effects of oxidation caused by such substances, eliminates image disturbance caused by triboelectric charging, and can stably obtain high-quality images over a long period of time.

[Means for solving problems]

According to the present invention, (A) an inorganic powder with a volume resistivity of 1010 Ω on the drawing board, (B) a conductive powder with a volume resistivity of less than 1010 Ω, and a film-forming resin with a surface resistance of 10120 or more after film formation (0). A pressure transfer type electrostatic recording device is provided, which is characterized in that a mixture is formed into a film on a rigid conductive base material directly or via another dielectric layer and used as a recording medium.

FIG. 1 shows a dielectric drum 1 serving as a recording medium in which a dielectric layer 2 is provided as a recording layer on a conductive base material 3.

Here, the shape of the recording medium is not limited to the drum shape as shown in FIG. 1, but may be belt-shaped or flat plate-shaped.

The conductive base material 3 is selected from aluminum, aluminum alloy, stainless steel, and other metals, and preferably has a thickness that is not deformed by pressure during pressure transfer or pressure transfer and simultaneous fixing. Also, to harden the surface of the conductive base material, or to increase the surface area of the conductive base material to improve the adhesion of the dielectric layer to be coated.

For example, anodic oxidation of an aluminum alloy surface or hard-from plating of a stainless steel surface may be performed.

Next, as a component constituting the dielectric layer 2, the film-forming resin (component C) should have a surface resistance of 1012Ω or more, preferably 10130 or more after film formation, in order to obtain a stable electrostatic latent image. It is appropriate to look at it.

Specifically, the film-forming resin used is, for example, polyimide, I-lyamide imide, I-lyamide, preester imide, polyester, polyvinyl formal, polyoxy resin, polyurethane, melamine resin, acrylic resin, polymethyl methacrylate, polyester, etc. Acrylamide, silicone resin, silicone polyimide resin, silicone epoxy resin, silicone ester resin, imide epoxy resin, urethane acrylate resin, epoxy p v L/
-to resin, phenolic resin, 4-reacetal, fu.

Examples include base resins.

In addition, the inorganic powder as a component constituting the dielectric layer has a volume resistivity of 10100, preferably 10Ω,
1 or more, the volume resistivity of the entire dielectric material can be increased, and a stable electrostatic latent image can be obtained. Further, the average particle size is preferably 10 μm or less, whereby the dispersibility of the inorganic powder in the coating film is good and a uniform coating film can be obtained. Such inorganic powders include, for example, alumina, magnesium oxide, etc. Ronitride, asbestos, silica,
Glass powder, natural mica, synthetic mica, barium titanate,
Magnesium titanate, zirconium titanate, zircon, beryllia, etc. or mixtures thereof can be used. The particle size distribution of the inorganic powder may be uniform;
Further, particles of different particle sizes may be combined so that the dielectric layer has a structure as dense as possible, and flaky or fibrous particles may also be used.

The mixing ratio of the inorganic powder (component A) and the film-forming resin (component C) is in the range of 100 parts by weight of the former to 5 to 300 parts by weight, preferably 20 to 200 parts by weight. If the amount of film-forming resin is less than 5 parts by weight, the impact resistance of the dielectric will be reduced and the image will deteriorate in a high humidity environment. On the other hand, if the amount exceeds 300 parts by weight, ozone resistance deteriorates and the dielectric surface is likely to be cut or scratched by the cleaner, so that sufficient durability cannot be obtained.

Further, the conductive powder used as component (B) has a volume resistivity of less than 10,100 mm. Volume resistivity is 1010
Ω・If you are on a tilted board, you will be more susceptible to the effects of frictional electrification.

Preferably, the volume resistivity is 10 7 Ω·α or less. Further, the average particle size of the conductive powder is preferably 10 μm or less, more preferably 5 μm or less. When the average particle size exceeds 10 μm, the dispersibility of the conductive powder in the coating film tends to decrease. Such conductive powder is, for example, 5n02 e 5n0
Tin oxide-based inorganic oxides such as 2-Ti02 e 5n02-BaS04, iron sesquioxide, triiron tetroxide, di-sepisodic oxide,
Kel, zinc oxide, other metal oxides, or silicon carbide, precursor? monofluoride, car? /Non-oxidizing inorganic compounds such as black, or fine metal powders such as copper, zinc, aluminum, silicon, iron, cobalt, copper, manganese, tungsten, tin, antimony, etc., or highly conductive treated materials themselves. Resistance (volume resistance 1010
(Ω・α or more) inorganic fine powders include silicon dioxide, activated clay, acid clay, kaolin, alumina powder, zeolite, etc., electrolessly plated with gold, silver, copper, nickel, etc.

By using conductive powder with a volume resistivity of less than 1010Ω·tan as a component for forming the dielectric layer, a stable electrostatic latent image can be obtained without significantly reducing the surface resistance of the dielectric layer. A dielectric layer is provided that does not cause image disturbance due to frictional charging with plain paper serving as transfer paper or a pressure roller. The amount of the conductive powder (B) added is in the range of 0.1 to 100 parts by weight, preferably 1 to 50 parts by weight, per 100 parts by weight of the inorganic powder (Component (2)). Addition amount is 0.1
If it is less than 1 part by weight, the effect of suppressing triboelectric charging will be insufficient, while if it exceeds 100 parts by weight, the volume resistivity of the coating film as a whole will decrease, making it impossible to obtain a stable electrostatic latent image.

In order to form a dielectric layer as described above on a conductive base material, the mixture may be extruded and coated on the conductive base material or on a conductive base material on which another dielectric layer is formed. Alternatively, a diluent may be added to the mixture to form a liquid, and this may be coated.

Next, a preferred mode of creating a recording medium will be described. In the case of a drum-shaped recording medium, a cylinder is made of a conductive base material such as aluminum, aluminum alloy, or stainless steel. The wall thickness of the cylinder at this time needs to be thick enough to withstand pressure during pressure transfer or pressure transfer simultaneous fixing. 10- for aluminum and aluminum alloys
It is desirable that there be at least one. Next, the above-mentioned inorganic powder of component (A), conductive powder of component ψ), film-forming resin of component (C) and, if necessary, a solvent and a curing agent are applied to the cylinder surface directly or through another dielectric layer. A film is formed by applying and drying a paint containing a dispersion aid, hardness-improving additives, pigments, dyes, etc. The film thickness at this time is desirably at least 3 μm or more, preferably 10 μm or more in order to maintain electrical insulation.

Next, the dielectric drum prepared as described above is incorporated into an electrostatic recording apparatus shown in FIG. 2 as a recording medium.

To briefly describe the configuration of the electrostatic recording apparatus shown in FIG. 2, an electrostatic latent image is formed using a recording head 4, and the method is a multi-stylus disclosed in Japanese Patent Publication No. 36-4119. or JP-A No. 53-96834, No. 54-535
Any of the ion implantation types disclosed in Publication No. 37 can be used, and basically they are dot-shaped and have a dielectric material 2.
Any material may be used as long as it can form an electrostatic latent image on its surface. Preferably, the latter type of ion implantation, which does not involve direct discharge between the dielectric 2 and the recording medium 4, is used.

Next, the electrostatic latent image formed by the above-described method is visualized in the developing section 5, and then transferred onto the plain paper 9 by pressure by the pressure roller 7. In this case, if a pressure fixable toner is used, the visible image is transferred to the plain paper and fixed at the same time. Next, in accordance with a conventional method, the recording medium after the visible image has been transferred is neutralized by a static eliminator unit 8, and the toner on the transfer plate is removed by a cleaner unit and a toner.

For electrostatic recording, in order to record an electrostatic latent image in accordance with an image signal on a dielectric drum l using Do 4, Japanese Patent Laid-Open No. 54-78134 is used.
The ion generator disclosed in the publication can be used for electrostatic recording.

The electrostatic recording head 4 is comprised of a dielectric 35, a drive electrode 36, a control electrode 37, and a screen electrode 39 having an ion emitting annotation 38, as shown in FIG. An AC voltage is applied between the drive electrode 36 and the control electrode 37 by a power supply 34, and a DC voltage is applied from the power supply 31 between the control electrode 37 and the conductive base 3 of the dielectric drum 1 via a switch 33. is applied, and a DC voltage is applied between the screen electrode 39 and the conductive substrate 3 from the power source 32. Drive electrode 36
Due to the alternating current voltage applied between the control electrode 37 and the control electrode 37, positive and negative ions are generated alternately. If the image signal indicates that the switch 33 is on (conducting to the contact Y), the negative ions are accelerated and reach the dielectric layer 2 of the dielectric drum 1.
Retained.

At this time, since positive ions are not accelerated, they are discharged between them and the control pole 37. If there is no image signal and the switch 33 is off (conducting to contact X), both positive and negative ions will not be accelerated and will be discharged between them and the control electrode 37.

In this way, an electrostatic latent image can be recorded according to the image signal.

Next, an example will be described.

[Example 1] Cyclized butadiene rubber paint JSRCBR-M (trade name of Nippon Gosei Pum Co., Ltd., containing 80 xylene) was applied to the outer peripheral surface of an aluminum alloy cylinder with an inner diameter of 60 cm, an outer diameter of 100 cm, and a length of 230 cm. After coating, the cylinder was heated and dried at 180° C. for 60 minutes to obtain a cylinder having a coating thickness of 3 μm.

In this cylinder, add UV-curable niboxy acrylate paint 2-ethylanthraquinone (photoreaction accelerator) 1.0.
9 Methyl ethyl ketone 40.9
The paint obtained by mixing was applied, dried at 80°C for 10 minutes, and then heated with a 4 kW concentrating ultraviolet lamp at a irradiation distance of 15 cIR.
The cylinder was irradiated for 30 seconds to obtain a cylinder having a coating film with a thickness of 19 μm including the cyclized tutadiene rubber layer formed with a coating thickness of 16 μm.

[Example 2] The cylinder used in Example 1 (3 in the same cylinder as the 3 μm layer of cyclized Ptagenco9), tin oxide (Sn0
2) Surface resistance after powder 5I film 8.
2 x 1015Ω) butyl acetate
Apply the paint obtained by mixing 40p and heat it at 80°C.
After drying for 0 minutes, use a 4 kW concentrating ultraviolet lamp at an irradiation distance of 1
53 for 30 seconds to obtain a cylinder having a coating film with a thickness of 21 μm including a 9-μm layer of cyclized butadiene comb formed with a coating thickness of 18 μm.

[Comparative Example 1] A cylinder with a coating thickness of 20 μm (including a 3 μm layer of cyclized butadiene) was prepared in the same manner as in Example 1, except that the tin oxide used for surface coating in Example 1 was removed. I got it.

[Comparative Example 2] A coating film thickness of 18 μm (including a cyclized butadiene co-9m layer of 3 μm) was prepared in the same manner as in Example 1, except that the alumina and potassium tetrasilicon mica used for surface coating in Example 1 were removed. I got a cylinder.

Comparative tests were conducted on Examples 1 and 2 and Comparative Examples 1 and 2 in the manner described below, and the following results were obtained.

[Test 1] The recording cylinders of Examples 1 and 2 and Comparative Example 1 were assembled into the electrostatic recording device described above, and a pressure roller made of polyacetal was brought into contact with the pressure roller and rotated to reduce the friction with the pressure roller. Charge was measured as the surface potential of the recording cylinder. The applied pressure is 10019. The results are shown in Table 1. Values are absolute values. In addition, the surface of the pressure roller was statically neutralized using a static eliminating needle each time.

Table 1: Amount of triboelectric charge (unit: V) From Table 1, it can be seen that the triboelectric charge is reduced by mixing the conductive fine powder.

[Try #! 2] Corona irradiation was performed for Examples 1 and 2 and Comparative Example 2,
The changes in surface conditions were compared. The corona irradiation time was 300 minutes, and the surface resistance before and after durability was measured at room temperature, room temperature (23℃,
6(1) and high temperature and high humidity (33°C, 9 on).The results are shown in Table 2.

Table 2 Surface resistance (unit: Ω) From Table 2, it can be seen that the corona resistance was improved by mixing inorganic materials. [Effects of the invention] As explained above, transfer type electrostatic recording devices, especially pressure transfer type The electrostatic recording device has a volume resistivity of 1010Ω・
By using a recording medium provided as a dielectric layer with a mixture consisting of one or more inorganic powders, fine powders with a volume resistivity of less than 1010Ω/α, and film-forming resins with a surface resistance of 10120 or more, good corona resistance properties can be achieved. We were able to obtain an electrostatic recording material that was strong and free from the adverse effects of triboelectric charging on the dielectric surface.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a dielectric drum as a recording medium, and FIG. 2 is a schematic diagram of essential parts of an example of an electrostatic recording device incorporating the dielectric drum of FIG. 1. FIG. 3 shows the steps for electrostatic recording. 1: dielectric drum, 2: dielectric layer, 3: conductive base material, 4
: Recording head, 5: Developing device, 6: Cleaner set, 7
: Pressure roller, 8: Static eliminator, 9: Plain paper.

Claims (3)

[Claims] (1) (A) Inorganic powder with a volume resistivity of 10^1^0 Ωcm or more, (B) conductive powder with a volume resistivity of less than 10^1^0 Ωcm, and (C) surface resistance after film formation. 10^1^
A pressure transfer electrostatic method characterized by using a mixture of a film-forming resin having a resistance of 2Ω or more on a rigid conductive substrate directly or through another dielectric layer as a recording medium. Recording device. (2) The above mixture contains 100 parts by weight of the above component (A), 0.1 to 100 parts by weight of the component (B), and 5 to 100 parts by weight of the component (C).
The electrostatic recording device according to claim 1, comprising 300 parts by weight. (3) Volume resistivity 10^7Ω・c as the above component (B)
The electrostatic recording device according to claim 1 or 2, which contains at least one kind of inorganic fine powder having a particle size of m or less.