JPH0352053B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electrostatic recording medium, particularly an electrostatic recording medium that can be used multiple times. [Prior Art] Conventionally, electrostatic recording paper in which a conductive layer is provided between the recording layer and the base paper is generally used as a recording medium in an electrostatic recording device, and a needle electrode such as a multi-stylus is attached to the surface of the recording layer. An electrostatic latent image is formed using toner, which is developed and fixed with toner to obtain a recorded image. 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 disadvantages such as being highly susceptible to the atmosphere (moisture, heat, etc.) during use. Moreover, since electrostatic recording paper itself is special compared to plain paper, it has the disadvantage that running costs are significantly higher when used as a consumable item. To solve these drawbacks, electrostatic recording devices that transfer onto plain paper have been developed (for example, the
Publication No. 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 10 ¹² Ω·cm or more is provided on a biaxially stretched polyester base material, and a needle electrode is connected to the recording medium using a multi-stylus. The dielectric surface is charged by applying a high voltage between the surface and the dielectric surface, and the electrostatic latent image formed is then developed with toner to obtain a powder image, which is then printed on plain paper. Images are obtained by electrostatic transfer. However, since this method electrostatically transfers toner images onto plain paper, the transfer efficiency is as low as about 80%, which reduces image density and is disadvantageous in terms of cleaning and scattering of residual toner. Image distortion occurs due to electrical 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, and after this latent image is developed with toner, it is transferred and fixed onto plain paper using pressure. The method is known (for example, JP-A-54-78134, JP-A-55-
134872). In this method, the dielectric thin layer is rubbed by the paper, resulting in its surface being polished. Therefore, in order to increase the hardness of the dielectric layer, inorganic dielectrics such as anodized aluminum, Al ₂ O ₃ formed by thermal spraying, and glass enamel, and organic dielectrics such as polyamide, polyimide, and fluororesin are used. But anodized aluminum, thermal sprayed
Inorganic dielectric layers such as Al ₂ O ₃ and 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 surface cutting by cleaners and scratches, 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, during long-term use, these organic recording layers are subject to oxidation by ozone under a high electric field, resulting in a decrease in moisture resistance. Polyimide and polyamide resins are weak against impact and are prone to crack-like scratches, causing peeling at these locations.Furthermore, pressure transfer methods have a high surface energy, resulting in a transfer efficiency of 80%.
It tends to be low. Further, although fluororesin has good transfer efficiency, it is soft and easily causes scratches. Furthermore, in the case of the pressure transfer method, since the surface of the dielectric layer contacts the plain paper and the processing roller under pressure, triboelectric charges are induced on the surface of the dielectric layer. The polarity and amount of charge induced at this time vary depending on the material of the pressure contact member, such as the composition of the transfer material and the resin composition of the pressure roller, the surface roughness of the pressure contact member, and the temperature and humidity of the usage environment. The impact is significant. 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 triboelectrification on the dielectric surface promotes the adhesion of discharge products and charged fine particles such as paper dust, and when these adhering substances absorb moisture, the surface resistance decreases significantly. This will have 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 formation of an electrostatic latent image may be inhibited, resulting in adverse effects such as image blurring and white spots. In order to eliminate the above-mentioned drawbacks, it is possible to stabilize triboelectric charging by reducing the occurrence of triboelectrification or by increasing the attenuation rate of the triboelectric potential by using a dielectric material with a low insulation resistance value. However, a material with a low resistance value could not be used because the surface resistance of the dielectric material would also decrease, making it impossible to obtain a stable electrostatic latent image and distorting the image. As mentioned above, it is not easily affected by moisture in the air, has good transfer efficiency, and has excellent abrasion resistance, impact resistance,
No material has yet been obtained that simultaneously satisfies all the characteristics of ozone resistance, has no adverse effect on images due to triboelectrification, and is durable for long-term use. [Problems to be Solved by the Invention] The object of the present invention is to use 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 a recording medium onto plain paper. A recording medium that can be used multiple times, has good toner transfer efficiency without being affected by oxidation caused by ozone, etc., prevents negative effects on images due to frictional charging, and is a good recording medium that can provide high-quality images over a long period of time. An object of the present invention is to provide an electrostatic recording medium. [Means for Solving the Problems] That is, the present invention provides an electrostatic recording medium that is used in a transfer method and has a dielectric layer and a conductive base material, in which the dielectric layer contains the following components (A) to (D). ) (A) Inorganic powder with a volume resistivity of ^10-10 Ω・cm or more (B) Film-forming resin with a surface resistance of ^10-12 Ω or more after film formation (C) Lubricant with a static friction coefficient of 0.4 or less and surface migration properties A fluorine-containing block copolymer having a functional segment having the following properties and a compatible segment that is compatible with the film-forming resin ^, or the fluorine-containing block copolymer (D); a mixture containing a powder, said mixture comprising said component (A);
It contains 0.1 to 100 parts by weight of the component (D) per 100 parts by weight, and the dielectric layer is formed directly on the conductive substrate or via another dielectric layer. It is an electrostatic 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 body 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. In addition, in order to soften the surface of the conductive base material or increase the surface area of the conductive base material to improve the adhesion of the coated dielectric layer, for example, anodizing the aluminum alloy surface or hardening the stainless steel surface. Chrome plating may also be performed. Next, the film-forming resin (component (B)) used as a component of the dielectric layer 2 has a surface resistance of 10 ¹² Ω after film formation.
As mentioned above, preferably 10 ¹³ Ω or more is appropriate from the viewpoint of obtaining a stable electrostatic latent image. Specifically, the film-forming resins used include, for example, polyimide, polyamideimide, polyamide, polyesterimide, polyester, polyvinyl formal, epoxy resin, polyurethane, melamine resin, acrylic resin, polymethylmethacrylate, polyacrylamide, and silicone resin. , silicone polyimide resin, silicone epoxy resin, silicone ester resin, imide epoxy resin, urethane acrylate resin, epoxy acrylate resin, phenolic resin, polyacetal,
Examples include fluororesin. In addition, the volume resistivity of the inorganic fine powder of component (A) is
It is desirable that the resistance is 10 ¹⁰ Ω·cm or more, preferably 10 ¹¹ Ω·cm or more, so that the volume resistivity of the entire dielectric can be increased and a stable electrostatic latent image can be obtained. Furthermore, it is preferable that the average particle size is 10 μm or less, so that the dispersibility of the fine powder in the coating film becomes good and a uniform coating film can be obtained. Specifically, such fine powders include alumina, magnesium oxide, boron nitride, asbestos, silica, glass powder, natural mica, synthetic mica, barium titanate,
Magnesium titanate, zirconium titanate,
Zircon, beryllia, etc. or mixtures thereof can be used. In particular, by using fluorine mica in which the water of crystallization (OH) in natural mica crystals is replaced with fluorine (F), a dielectric layer with good image characteristics even under high humidity can be obtained. The particle size distribution of the inorganic fine powder (component A) may be uniform, or may be a combination of particles with different particle sizes so that the dielectric layer has a structure as dense as possible, and A flaky or fibrous material may also be used. The mixing ratio of the inorganic fine powder (component A) and the film-forming resin (component B) is 100 parts by weight of the former to 5 to 5 parts by weight of the latter.
300 parts by weight, preferably in the range of 20-200 parts by weight. If the film-forming resin is less than 5 parts by weight, the impact resistance of the dielectric will decrease and image deterioration will occur in a high humidity environment, while if it exceeds 300 parts by weight, the ozone resistance will decrease and the dielectric will be damaged by the cleaner. Sufficient durability cannot be obtained because the surface is easily cut or scratched. Next, as component (C) of the mixture, a fluorine-containing block copolymer such as a lubricant having a static friction coefficient of 0.4 or less at 25°C and/or an A-B type block polymer containing a fluoroalkyl group is used. .
If the static friction coefficient exceeds 0.4, sufficient sliding properties and developer transfer efficiency cannot be obtained. Examples of the lubricant component (C) include fluorine-containing compounds such as polytetrafluoroethylene and polycarbon monofluoride, as well as polyethylene and nylon. By using one or more of the above lubricants as component (C) of the mixture, the releasability, non-adhesiveness, smoothness, and slipperiness of the dielectric layer can be improved, and the transfer of the developer can be improved. Efficiency is increased, organic components in the developer are less likely to adhere to the dielectric layer, and the wear resistance of the dielectric layer is improved. The fluorine-containing block copolymer used in the present invention is
It has a functional segment that has surface migration properties and a compatible segment that is compatible with the above-mentioned film-forming resin. Specifically, it is an A-B type block copolymer obtained by block polymerizing a fluorine-containing monomer component (for example, the fluorine-containing alkyl group described below) that acts as a functional segment on one end of a polymer that acts as a compatible segment. be. The fluorine-containing monomer component that acts as a functional segment is -CH ₂
(CF ₂ ) ₂ H, −CH ₂ (CF ₂ ) ₄ H, −CH ₂ CF ₃ , −CH ₂ CH ₂
Fluoroalkyl groups such as ( _{CF2 ) 7CF3 , -CF3} , _C2F6 are preferred. Further, as the polymer that acts as a compatible segment, one containing a vinyl monomer component is preferable, and specifically, polymethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, etc. are suitable. A-B containing this fluoroalkyl group as one component
The compatible segments of the type fluorine-containing block copolymer are compatible with the film-forming resin, making it possible to improve the adhesion of the coating film to the substrate and the hardness, and also act as functional segments. The fluoroalkyl group migrates to the surface and can improve the water repellency, mold releasability, non-adhesiveness, and slipperiness of the coating surface. These points cannot be obtained when random polymers of the same composition are used. These fluorine-containing block copolymers can be synthesized using polymeric peroxide as a polymerization initiator [Proceedings of the 33rd Annual Conference of the Society of Polymer Science and Technology, p. 266 (Vol. 33, No. 2, 1984 Year)〕. Furthermore, as the fluorine-containing block copolymer, Moviver F100, F110, F200, and F210 manufactured by NOF Corporation can be used. This fluorine-containing block copolymer is a preferred lubricant not only for improving the transfer efficiency and abrasion resistance as described above, but also for obtaining an electrostatic recording material with always stable electrical properties without being subjected to ozone oxidation. The reason for this is not yet fully understood, but one reason is that fluoroalkyl components are resistant to ozone oxidation.
The substrate component obtained by block polymerization is easily compatible with the film-forming resin (B) component used, and it is inferred that the fluoroalkyl component is regularly distributed on the surface of the recording medium in an extremely microscopic state. be done. The blending amount of these lubricants is 0.001 to 100 parts by weight of component (A) inorganic powder.
300 parts by weight, preferably in the range of 0.01 to 100 parts by weight. If the amount is less than 0.001 part by weight, the effect of improving mold releasability and slipperiness will not be sufficient, while if it exceeds 300 parts by weight, the impact resistance of the resulting coating film will decrease. Further, as component (D) of the mixture, an inorganic powder having a volume resistivity of less than 10 ¹⁰ Ω·cm is used to make it less susceptible to triboelectric charging. Preferably the volume resistivity is
10 ⁷ Ω・cm or less. Further, the average particle size of the inorganic powder of component (D) is preferably 10 μm or less. If it exceeds 10 μm, the dispersibility of the inorganic powder in the coating film tends to decrease. Such inorganic powders include, for example, SnO ₂ , SnO ₂ −
Tin oxide-based inorganic oxides such as TiO ₂ , SnO ₂ -BaSO ₄ , iron sesquioxide, triiron tetroxide, nickel sesquioxide, zinc oxide and other metal oxides, silicon carbide, polycarbon monofluoride, Non-oxidizing inorganic compounds such as carbon black, fine metal powders such as copper, zinc, aluminum, silicon, iron, cobalt, nickel, manganese tungsten, tin, antimony, etc., or conductive treated materials with high resistance (volume) Resistance 10 ¹⁰ Ω・cm or more)
Examples of inorganic fine powders include silicon dioxide, activated clay, acid clay, kaolin alumina powder, zeolite, etc., which are electrolessly plated with gold, silver, copper, nickel, etc. By using an inorganic powder (component D) with a volume resistivity of less than 10 ¹⁰ Ω・cm 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. At the same time, a dielectric layer is provided that does not cause image disturbance due to frictional electrification with the plain paper used as the transfer paper or the pressure roller. The blending amount of component (D) is 0.1 per 100 parts by weight of component (A).
~100 parts by weight. If the amount is less than 0.1 part by weight, the effect of suppressing frictional charging will not be sufficient, and if it exceeds 100 parts by weight, the adhesion of the coating film to the substrate will decrease. There is a delicate correlation between the releasability and smoothness of the dielectric surface, the transfer efficiency of the transfer material, and triboelectric charging.
Good images can only be obtained by using a dielectric layer obtained by adding the aforementioned lubricant, a fine powder with a volume resistivity of less than 10 ¹⁰ Ω·cm, to a film-forming resin with a volume resistivity of 10 ¹² Ω·cm or more. can be obtained stably over the long term. In order to form a dielectric layer as described above on a conductive base material, the mixture is 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 make it into a liquid, and this may be used for coating. 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. In the case of aluminum and aluminum alloys, it is desirable to have a thickness of 10 mm or more. Next, the components used in the present invention are applied directly to the cylinder surface or through another dielectric layer.
(A), (B), (C) and (D) Furthermore, if necessary, a solvent, a curing agent,
A coating containing a dispersion aid, hardness improving additive, pigment, dye, etc. is applied and dried to form a film. The film thickness at this time should be at least
The thickness is desirably 3 μm or more, preferably 10 μm or more. Next, the dielectric drum prepared as described above is incorporated into an electrostatic recording apparatus shown in FIG. 2 as a recording medium. The configuration of the electrostatic recording device shown in FIG. 2 will be described in detail.
The electrostatic latent image is formed using the recording head 4,
The method is the multi-stylus disclosed in Japanese Patent Publication No. 36-4119, or the method disclosed in Japanese Patent Application Publication No. 53-96834,
Any of the ion implantation type disclosed in Japanese Patent Publication No. 54-53537 can be used, and basically any type that can form an electrostatic latent image on the surface of the dielectric 2 in a dot shape may be used. Preferably, a type that does not involve direct discharge between the dielectric 2 and the recording head 4, such as the latter ion implantation type, is used. Next, the electrostatic latent image formed by the above method is visualized in the developing section 5, and then the pressure roller 7
is transferred onto plain paper 9 by pressure. 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 the static eliminator unit 8, and the residual toner remaining after the transfer is removed by the cleaner unit 6. Note that in order to record an electrostatic latent image on the dielectric drum 1 using the electrostatic recording head 4 in accordance with an image signal, Japanese Patent Laid-Open No. 54
The electrostatic recording head (ion generator) disclosed in Japanese Patent No. 78134 can be used. The electrostatic recording head 4 includes a dielectric 3 as shown in FIG.
5, drive electrode 36, control electrode 37,
It consists of a screen electrode 39 with ion emitting apertures 38. An AC voltage is applied between the drive electrode 36 and the control electrode 37 by the power supply 34, and a DC voltage is applied from the power supply 31 between the control electrode 37 and the conductive substrate 3 of the dielectric drum 1 via the switch 33. A voltage 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
By the alternating current voltage applied between the control electrode 37 and the control electrode 37, positive and negative ions are generated alternately.
If the switch 33 is turned on (conducted to the contact Y) by the image signal, the negative ions are accelerated and reach the dielectric layer 2 of the dielectric drum 1, where they are held. At this time, since positive ions are not accelerated, they are discharged between them and the control electrode 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. In the examples, the static friction coefficient is the object (lubricant)
This is the value when the friction coefficient is stationary on the same material, and it is actually the value measured by Toyo Seiki's TSS type friction coefficient tester. Example 1 After applying cyclized butadiene rubber paint JSR CBR-M (product of Japan Synthetic Rubber Co., Ltd., containing 80% xylene by weight) to the outer peripheral surface of an aluminum alloy cylinder with an inner diameter of 60 mm, an outer diameter of 100 mm, and a length of 230 mm, 60℃
The cylinder was heated and dried for 30 minutes to obtain a cylinder coated with a film thickness of 3 μm. In this cylinder, (1) potassium tetrasilicon mica, which is a synthetic mica [KMg _2.5
(Si ₄ O ₁₀ )F ₂ ] powder (volume resistivity 5.0×10 ¹⁴ Ω・
cm; average particle size 2.5μm) 30g (2) Alumina (Al ₂ O ₃ ) powder (volume resistivity 4.0×
10 ¹⁴ Ω・cm; average particle size 1.0μm) 70g (3) Tin oxide (SnO ₂ ) powder (volume resistivity 1Ω・
cm; average particle size 0.1 μm) 5 g (4) A-B type block polymer containing a fluoroalkyl group as one component Modeiver F200 (product of NOF Corporation) 5 g (5) UV-curable epoxy acrylate paint (resin 100%) Unidek V5502 (product of Dainippon Ink & Chemicals Co., Ltd.) (Surface resistance after biofilm 8.0
×10 ¹⁵ Ω) 70g (6) 2-ethylanthraquinone (photoreaction accelerator)
Apply the paint obtained by mixing 1.4g (7) of 50g of methyl ethyl ketone, dry at 80℃ for 10 minutes, and then use a 4kW concentrating ultraviolet lamp at an irradiation distance of 15cm.
The cylinder was irradiated for 30 seconds to obtain a cylinder having a coating film with a thickness of 18 μm including a cyclized butadiene rubber layer formed with a coating thickness of 15 μm. Example 2 In the same cylinder as that used in Example 1 (cyclized butadiene rubber layer 3 μm), (1) Fluorine phlogopite [KMg ₃
(AlSi ₃ O ₁₀ )F ₂ ] (volume resistivity 80×10 ¹⁵ Ω・cm;
325 mesh or less) 5g (2) Alumina (Al ₂ O ₃ ) powder (volume resistivity 4.0×
10 ¹⁴ Ω・cm; average particle size 1.0 μm) 90 g (3) Polycarbon monofluoride powder (volume resistivity 2.0×10 ³ Ω・cm; average particle size 1.0 μm, static friction coefficient 0.02) 20 g (4) Fluoroalkyl A-B type block polymer with a group as one component Modeiver F100 (product of NOF Co., Ltd.) 1g (5) UV-curable urethane acrylate paint (resin content 75%) Unidec 17-824 (Dainippon Ink & Chemicals Co., Ltd.) Co., Ltd. product) (Surface resistance after film formation: 8.2
×10 ¹⁵ Ω) 50g (6) Apply the paint obtained by mixing 40g of butyl acetate, dry it at 80℃ for 10 minutes, and then use a 4kW concentrating ultraviolet lamp at an irradiation distance of 15cm.
The cylinder was irradiated for 30 seconds to obtain a cylinder having a coating film with a thickness of 15 μm including the cyclized butadiene rubber layer formed with a coating thickness of 12 μm. Comparative Example 1 The coating thickness was determined in exactly the same manner as in Example 1, except that the tin oxide used for surface coating in Example 1 was removed.
A cylinder of 17 μm (including a 3 μm cyclized butadiene rubber layer) was obtained. Comparative Example 2 A cylinder was prepared and coated in exactly the same manner as in Example 1, except that the A-B type block polymer Modeler F200 containing a fluoroalkyl group as one component, which was used for surface coating in Example 1, was removed. Film thickness 18μm
A cylinder (including a cyclized butadiene rubber layer of 3 μm) was obtained. Comparative Example 3 Unidec used for surface coating in Example 1
A cylinder with a coating thickness of 19 μm (including the cyclized butadiene rubber layer) was obtained in exactly the same manner as in Example 1 using a mixture of V5502, 2-ethylanthraquinone, and methyl ethyl ketone (excluding other ingredients). Comparative experiments were conducted on Examples 1 and 2 and Comparative Examples 1, 2, and 3 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 installed in the electrostatic recording device described above, and a pressure roller made of polyacetal was brought into contact with the pressure roller and rotated to cause frictional electrification with the pressure roller. was measured as the surface potential of the recording cylinder. The applied pressure is 100
Kg/ ^cm2 . The results are shown in Table 1. Values are absolute values. In addition, static electricity was removed from the surface of the pressure roller each time using a static electricity removal slope.

[Test 2]

For Example 2 and Comparative Example 2, durability was conducted by image formation. The durability conditions are as follows: Using the electrostatic recording device mentioned above, an electrostatic latent image is formed on the coating film of the recording cylinder, this is developed using dry pressure toner, and this toner image is simultaneously pressure-transferred to transfer paper. I established myself. The durability is 100,000 sheets using A4 paper. The transfer efficiency of both recording cylinders before and after this durability test was compared. The results are shown in Table 2.

[Table] The transfer efficiency was calculated by subtracting the weight of the transfer paper before transferring the toner image from the weight of the transfer paper after transfer, giving the transferred toner amount ag, and taking the residual toner on the recording medium as bg, as a/a+b×100. . From Table 2, it was found that the mixing of the surface lubricant had a large effect on the transfer efficiency. [Test 3] Examples 1 and 2 and Comparative Example 3 were subjected to corona irradiation, and 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 and humidity (23℃, 60%) and at high temperature and humidity (33℃, 60%).
90%). The results are shown in Table 3.

〔Effect of the invention〕

As explained above, a transfer type electrostatic recording device,
Volume resistivity is especially important for pressure transfer electrostatic recording devices.
10 Inorganic powder and volume resistivity of ¹⁰ Ω・cm or more
By using a recording medium provided with a dielectric layer made of powder and lubricant with a diameter of less than 10 ¹⁰ Ω・cm, the dielectric surface has good corona resistance, toner transfer efficiency is good, and the dielectric layer can be easily removed by frictional charging. We were able to prevent any negative effects on the 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 recording head. 1: dielectric drum, 2: dielectric layer, 3: conductive base material, 4: recording head, 5: developer, 6: cleaner set, 7: pressure roller, 8: static eliminator,
9: Plain paper.

Claims (1)

[Claims] 1. An electrostatic recording medium having a dielectric layer and a conductive base material used in a transfer method, wherein the dielectric layer has the following components (A) to (D) (A) and has a volume resistivity. Inorganic powder with a resistance of 10 ¹⁰ Ω・cm or more (B) Film-forming resin with a surface resistance of 10 ¹² Ω or more after film formation (C) Film formation with a lubricant with a static friction coefficient of 0.4 or less and a functional segment with surface migration properties A fluorine-containing block copolymer having a compatible segment that is compatible with the resin used, or the fluorine-containing block copolymer (D) containing a mixture containing an inorganic powder with a volume resistivity of less than ^10-10 Ωcm. , the mixture contains the component (A)
It contains 0.1 to 100 parts by weight of the component (D) per 100 parts by weight, and the dielectric layer is formed directly on the conductive substrate or via another dielectric layer. electrostatic recording medium. 2. The electrostatic recording medium according to claim 1, wherein the mixture contains 5 to 300 parts by weight of component (B) and 0.001 to 300 parts by weight of component (C) per 100 parts by weight of component (A). . 3 At least one of the components (D) has a volume resistivity
The electrostatic recording medium according to claim 1, which is an inorganic powder having a resistance of 10 ⁷ Ω·cm or less.