JP2005156636A - Intermediate transfer body and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transfer body for outputting image of proper reproduction by improving transfer efficiency of toner from a photoreceptor, to the intermediate transfer body and from the intermediate transfer body to an image support, and eliminating image defects during each transfer. <P>SOLUTION: The intermediate transfer body 5 is used for an image forming apparatus for transferring a toner image of the surface of the photoreceptor 1 having a photoconductor layer on the intermediate transfer body 5, and transferring the toner image on the intermediate transfer body 5 onto the image support 8, to form image. A surface layer 5d is formed on a surface to which the toner image of the intermediate transfer body 5 is transferred. The surface layer 5d contains one or more particulate silica, capable of dispersion in at least a solvent, particulate metal powder, a particulate-coloring agent, a particulate charge control agent or a particulate silicone-based material, and one or more of a resin or an oil-based material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an intermediate transfer member used in an electrophotographic image forming apparatus.

  Various methods have been proposed for electrophotography as shown in Patent Documents 1 to 3 below, but generally an electrostatic latent image is formed on the surface of a photoconductor made of a photoconductive substance, A system is used in which a latent image is developed with toner and then the toner is transferred to a transfer material such as paper.

  As a method of developing an electrostatic latent image using toner, a powder craft method (Patent Document 4), a cascade method (Patent Document 5), a magnetic brush method (Patent Document 6), and a fur brush method (Patent Document 7). Various dry development methods such as a contact development method (Patent Document 8), a pressure development method (Patent Document 9), and a magnetic toner method (Patent Document 10) are known. The most common of these are the cascade method and the magnetic brush method.

  On the other hand, as a method for transferring a toner image formed on a photosensitive member onto a support, there is a method using an intermediate transfer member which is employed in a color image forming apparatus such as a color copying machine. This method is a method for forming an image by transferring a toner image formed on a photosensitive member onto a support. This image forming method can easily form a multicolor image.

  In the image forming system using the intermediate transfer body, many characteristics are required for the intermediate transfer body that temporarily holds the toner image. For example, as a means to suppress the occurrence of scratches on the surface of the photosensitive member and extend the life of the photosensitive member when foreign matter (carriers, etc.) is caught in the nip portion between the photosensitive member and the intermediate transfer member, the surface of the intermediate transfer member is tomographically Is provided. As an advantage of this method, as shown in Patent Document 11, a nip at the transfer point between the photosensitive member and the intermediate transfer can be secured stably.

  Further, as described in Patent Documents 12 and 13, the surface of the intermediate transfer member is formed on the surface of the intermediate transfer member in order to cope with both contradictory properties of holding the toner image stably stably and simultaneously transferring the toner image to the support uniformly. Adhesion of toner is reduced by mechanically fixing fine particles smaller than 1/2 of the toner particle size and fine particles smaller than that, or particles simultaneously with or smaller than the toner particle size and particles smaller than 1/10 of the toner particle size. It has been proposed that

Patent Document 14 proposes a method of improving secondary transfer efficiency by wet-coating fine particles on the surface of an intermediate transfer member. Further, Patent Document 15 proposes that silica fine particles are fixed to the surface of the intermediate transfer member with a silane compound to improve the transfer efficiency and the cleaning property of the surface of the intermediate transfer member.
Japanese Patent Publication No.42-23910 Japanese Patent Publication No.43-24748 US Pat. No. 2,297,691 US Pat. No. 2,221,776 US Pat. No. 2,618,552 US Pat. No. 2,874,063 US Pat. No. 2,902,974 U.S. Pat. No. 2,811,465 US Pat. No. 3,152,012 US Pat. No. 3,909,258 Japanese Patent Laid-Open No. 1-198773 Japanese Patent Laid-Open No. 7-234592 Japanese Patent Laid-Open No. 9-281813 JP 10-319730 A JP 2002-162767 A

  As in the above prior art, it is an effective means to give the intermediate transfer member elasticity, and fixing fine particles on the surface of the intermediate transfer member is effective in improving the transfer efficiency to the image support.

  However, since one of the above prior arts is finally mechanically fixed, minute scratches are generated on the surface of the intermediate transfer member. Since this scratch changes the surface condition (mechanical and electrical), it is mentioned that image distortion occurs during transfer from the photoconductor to the intermediate transfer member and from the intermediate transfer member to the image support. Absent.

  Further, by using relatively large particles that are 1/2 or less of toner or equivalent or less, the particles are present on the surface of the intermediate transfer member. Therefore, when transferring the toner image from the photosensitive member to the intermediate transfer member and during the intermediate transfer There is no mention that image disturbance, transfer failure, or the like occurs during transfer from the body to the image support.

  Also, if the fine particles are not fixed uniformly, the entire image will be non-uniform in each transfer and transfer unevenness will occur, resulting in image defects due to density unevenness and voids in the image such as letters and fine lines, the thickness of the thin lines Various problems such as non-uniformity occur.

  In addition, since the above-mentioned problem does not focus on the toner and its surface, it becomes prominent at the time of high definition, high speed and high accuracy. Actually, when a high resolution (1200 dots / inch) pattern was confirmed, a slight amount of toner splattered in the vicinity of the toner image where a minute scratch was present on the image support, resulting in non-uniformity of fine lines and image distortion. It was observed. This image was seen from the initial stage, and became noticeable at an early stage by overlapping the number of printed sheets.

  Furthermore, in order to confirm the high-speed response, the speed of only the intermediate transfer unit is increased, and the presence of particles applied to the surface is confirmed. It was confirmed that the desired effect was greatly reduced. In other words, it can be inferred that the above measures are very effective at low speed, but are still insufficient for further speeding up, high definition, and high accuracy.

  Furthermore, another prior art proposes uniform deposition by wet. This method is effective for uniformly adhering fine particles, but because the adhesion to the surface of the intermediate transfer member is weak, it is peeled off by a cleaner or the like in the initial stage of printing, resulting in a more reliable high-definition, high-speed machine. Will not be able to handle.

  In another known example, hydrophobized fine particles (silica particles) are applied to the surface of the intermediate transfer member using a silane compound (liquid having a boiling point of 150 ° C. or lower) and dried (100 ° C. or lower). It has been proposed. In addition, a fine particle supply device in the machine or a method of adding the fine particles to the developer and supplying them to each surface is proposed. When the fine particles are uniformly attached to the surface of the intermediate transfer member, the same effect as described above can be obtained.

  However, the addition of fine particles into the supply means and the developer is not preferable for low cost and low energy because the apparatus configuration is complicated and the developer design is complicated. Even if the fine particles hydrophobized using the silane compound are attached to the surface of the intermediate transfer member, although there is a slight difference, the adhesion force is still weak as described above. A problem arises that the developer is peeled off due to friction of the developer or the like, and cannot be applied to a highly reliable high-definition and high-speed machine.

  In particular, in order to cope with future high speed, high definition, and high precision, the surface of the intermediate transfer member must be made more uniform and high performance. Further, when a new intermediate transfer member is used, the above-mentioned problem appears remarkably in the initial stage, so that the reliability of the entire apparatus is lost.

  The present invention improves the transfer efficiency of toner from the photosensitive member to the intermediate transfer member and from the intermediate transfer member to the image support in order to cope with future increases in speed, high definition, and high accuracy. An object of the present invention is to provide an intermediate transfer member capable of outputting an image having good reproducibility without defects and an image forming apparatus using the intermediate transfer member.

In order to achieve the above object, the first means of the present invention transfers a toner image on the surface of a photoconductor having a photoconductor layer to an intermediate transfer member, and transfers the toner image on the intermediate transfer member onto an image support. In an intermediate transfer member used for an image forming apparatus for forming an image,
A surface layer is formed on the surface of the intermediate transfer body to which the toner image is transferred, and the surface layer is at least fine particle silica, fine particle metal powder, fine particle colorant, fine particle charge control agent, or fine particle silicone type dispersible in a solvent. It contains at least one material and at least one type of resin or oil-based material.

  According to a second means of the present invention, in the first means, at least one of the fine particle silica, the fine particle metal powder, the fine particle colorant, the fine particle charge control agent, or the fine particle silicone material is dispersed, and the resin or oil-based material is dispersed. The solvent that dissolves one or more of the above is an organic solvent.

  According to a third means of the present invention, in the first or second means, the fine particle silica, the fine particle metal powder, the fine particle colorant, the fine particle charge control agent, or the fine particle silicone material is externally added to the surface of the toner. It is characterized by being the same kind of material as the material.

  According to a fourth means of the present invention, in the first to third means, the intermediate transfer member has an endless base composed of, for example, a cylindrical element tube, an elastic layer provided on the endless base, A surface layer provided on the elastic layer, and between the elastic layer and the surface layer, between the elastic layer and the endless substrate, between the elastic layer and the surface layer, and the elasticity A reinforcing / releasing layer is provided between the layer and the endless substrate.

  According to a fifth means of the present invention, in the fourth means, the reinforcing / releasing layer is made of a fluorine-based material or a polyimide-based material.

  A sixth means of the present invention is characterized in that, in the fourth or fifth means, a plurality of the reinforcing / releasing layers are formed.

  A seventh means of the present invention is the toner particle according to the first means, wherein the fine particle silica, the fine particle metal powder, the fine particle colorant, the fine particle charge control agent, or the fine particle silicone material has an average particle size to form the toner image. 1/10 or less.

  According to an eighth means of the present invention, in the first means, the content of the fine particles in the surface layer is restricted to a range of 60 to 97% by weight, and the weight of the surface layer is 0.5 g or more per 1000 square centimeters. It is characterized by being restricted to a range of 20 g or less.

  According to a ninth means of the present invention, in the first means, silica is used as an oil-based material as a fine particle of the surface layer, or a silicone-based resin is used as a fine material. It is characterized by.

  According to a tenth means of the present invention, there is provided a photosensitive member having a photoconductor layer, a charger for charging the surface of the photosensitive member, and exposing the charged surface of the photosensitive member based on image information to form an electrostatic latent image. An exposure unit for forming the electrostatic latent image, a developing unit for developing the electrostatic latent image with toner, an intermediate transfer member for transferring the toner image on the surface of the photosensitive member, and a toner image on the intermediate transfer member on the image support. In the image forming apparatus including the transfer device, the intermediate transfer member is an intermediate transfer member of the first to ninth means.

  In the present invention, as described above, at least one kind of fine particle silica, fine particle metal powder, fine particle colorant, fine particle charge control agent, or fine particle silicone material dispersible in a solvent is formed on the outer surface of the intermediate transfer member, A surface layer containing at least one oil-based material is formed.

  By adhering the fine particle material to the surface of the intermediate transfer member, an appropriate electrostatic adhesion force is given to the transferred toner so that the toner is smoothly transferred to the image support during transfer. That is, in order to relieve the mechanical and electrostatic pressure on the toner existing on the surface at the time of transfer, each toner particle is smoothly transferred onto the image support.

  In addition, since minute unevenness with good releasability is formed on the surface of the intermediate transfer member, it is possible to suppress the peeling discharge when the toner leaves and to perform the peeling smoothly. Is also suppressed.

For this reason, it is possible to cope with future high speed, high definition, and high precision, improve the transfer efficiency of the toner from the photoconductor to the intermediate transfer body and from the intermediate transfer body to the image support, and at the time of each transfer It is possible to provide an intermediate transfer member capable of outputting an image having good reproducibility without an image defect, and an image forming apparatus using the intermediate transfer member.

  The present inventors paid attention to the toner and its surface and the surface of the intermediate transfer body, the surface state of the intermediate transfer body, the state of the toner transferred to the surface of the intermediate transfer body, and the toner transferred from the intermediate transfer body to the image support. The present inventors have made extensive studies on the relationship between the state of the image, the occurrence of transfer unevenness, the image density unevenness, the image defect due to the void of the image such as characters and fine lines, and the uneven thickness of the fine lines.

  As a result, it has been found that the relationship between the material externally added to the toner surface and the surface state of the intermediate transfer member has a great influence on the image characteristics. In particular, it has also been found that the surface state of the intermediate transfer member must be controlled with high accuracy and the surface state must be maintained for a certain period of time in order to cope with future increases in speed, resolution, and accuracy.

  In the present invention, the average particle size of the fine particle material is preferably 1/10 or less, more preferably 1/15 or less, of the colored particles (toner particles) forming the image. If the average particle size of the fine particle material exceeds 1/10 of the image particles forming the image, the influence of the particle size of the fine particles is large when the image particles forming the image are transferred onto the layer containing the fine particles. Since it is involved, the image is disturbed by the particles. Further, the same image disturbance is likely to occur at the time of image transfer to the transfer body, which is not preferable. This is fatal for images that require high resolution.

  Further, the ratio of the dispersed fine particles to the organic material after coating and drying is preferably 60 to 97% by weight. When the blending amount of the organic material is increased, the surface becomes sticky depending on the material, or a feeling of firmness due to the organic material adhering to the surface is generated. Further, since an unnecessarily strong adhesive force is applied, transfer efficiency and image defects may occur in reverse, which is not preferable. If the blending amount of the organic material is small, it is easily removed due to insufficient adhesion of the fine particles to the intermediate transfer member, so that the original intended effect is reduced by half, which is not preferable.

  Organic materials that can be dissolved in organic solvents include silicone oils, silicone resins, styrene resins, styrene / acrylic copolymers, polyester resins, fluorine resins, etc. A material having adhesiveness to the surface and adhesiveness to the dispersed fine particles is preferable. More preferably, a more stable effect can be obtained by using a material having releasability from a printing material such as paper. Further, these can be used in a system in which one kind or a mixture of two or more kinds is used.

  As the solvent, an aqueous solvent or an organic solvent solvent can be used. Examples include alcohols (ethyl alcohol, isopropyl alcohol, etc.), aromatics (toluene, xylene, etc.), hydrocarbons (hexane, cyclohexane, etc.), ketones (acetone, 2-butanone, etc.), ethers ( Dimethyl ether, diethyl ether, etc.), aqueous systems (water, addition of dispersant / emulsifier, etc.) and the like, and a system in which one or two or more of these are mixed can be used.

  Further, the total weight of the coated and dried dispersed fine particles and the organic material or oil-based material is preferably 0.5 g or more and 20 g or less, more preferably 0.5 g or more and 10 g or less per 1000 square centimeters. Even if it is applied in excess of 20 g per 1000 cm 2, the effect does not change so much, and on the contrary, the deposits are liable to be detached, and the disadvantage is that the dropped substance contaminates the inside of the apparatus. On the other hand, if the adhesion amount is less than 0.5 g, the original intended effect is halved, which is not preferable.

  In other words, with the organic material that can be dissolved in a solvent, the fine particle material is fixed to the surface of the intermediate transfer member, and an appropriate electrostatic adhesion is given to the transferred toner. Make sure it is transferred smoothly to the body. That is, in order to relieve the mechanical and electrostatic pressure on the toner existing on the surface during each transfer, each toner particle is smoothly transferred onto the image support.

  In addition, because the surface of the intermediate transfer member has minute unevenness with good releasability, the discharge discharge when the toner leaves is suppressed and the separation is performed smoothly. Disturbance is also suppressed. In addition, since an organic material that is soluble in a solvent and has good adhesion to the intermediate transfer member is used, the characteristics can be maintained until the intermediate transfer member becomes compatible with the toner and its external additive. More preferably, it is preferable to take a design method in which the formed layer, fine particle material, and organic material that can be dissolved in a solvent are electrostatically opposite in polarity to the toner.

  Hereinafter, although the specific content of this invention is demonstrated, this invention is not limited by this.

  FIG. 1 shows a schematic configuration of an image forming apparatus according to an embodiment of the present invention. The configuration of the apparatus will be described with reference to the drawing. The main body is provided with a host device (not shown) for controlling the printer. This host device incorporates an image signal processing unit and a print command control unit.

  A belt-like photoconductor 1 stretched by three rotatable shafts is provided in the central portion from the right side of the main body. The belt-like photoreceptor 1 has a multilayer structure having a photosensitive layer (for example, organic photoconductor: OPC) on the surface and a conductive layer (for example, aluminum) below the photosensitive layer. The belt-like photosensitive member 1 runs in the direction of the arrow in FIG. 1, and around the belt-like photosensitive member, the charger 2, the exposure means 3, and the developing means 4 (4a) in the order of the arrow. 4b, 4c, 4d), an intermediate transfer member 5, an erase lamp 6, and a photosensitive member cleaning mechanism 7.

  The charger 2 is a corotron and charges the surface of the photoreceptor by discharging the corotron wire. The exposure means 3 is constituted by a laser diode, a polygon mirror, an fθ lens and a case in which they are housed, and forms an electrostatic latent image by exposing the charged photoreceptor surface based on image information to be recorded.

  The four developing units 4a, 4b, 4c, and 4d are of the same type, but store different color toners, for example, yellow, magenta, cyan, and black. The electrostatic latent image is visualized to form a color toner image.

  The intermediate transfer member 5 is a cylinder having a diameter of 80 to 150 mm, and is composed of a conductive cylindrical substrate (for example, an aluminum drum) and a surface layer (details will be described later) covering the same. The conductive cylindrical substrate is connected to ground. The intermediate transfer member 5 is pressed against the belt-like photosensitive member 1 with an appropriate pressure, contacts with a nip width of 2 to 20 mm, and the toner image formed on the belt-like photosensitive member 1 is in the belt at the nip portion. Is transferred onto the intermediate transfer member 5 by a voltage applied to the conductive layer of the photoconductor 1. The belt-like photosensitive member 1 and the intermediate transfer member 5 may be driven separately or one may be driven by the other.

  The erase lamp 6 removes the residual potential on the belt-like photoreceptor 1 after the toner image is transferred by light irradiation. The photoconductor cleaning mechanism 7 removes residual toner remaining on the belt-like photoconductor 1 after transfer. Similarly, the cleaning mechanism 15 removes the toner remaining on the intermediate transfer member 5 after the sheet is transferred. The cleaning mechanism 15 is retracted upward while the toner image is formed on the intermediate transfer member 5.

  The pre-transfer charger 10 has a function of making the toner surface potential on the intermediate transfer member 5 constant and facilitating transfer. A sheet cassette is provided below the belt-like photoreceptor 1. Above this paper cassette is a pickup roller 9, whereby the paper 8 is drawn out of the paper cassette and discharged through a registration roller 11, a transfer roller 12, a static eliminator 13, and a fixing device 14.

  The registration roller 11 is for aligning the front end of the paper 8. The transfer roller 12 is for transferring the toner image formed on the intermediate transfer body 5 onto the paper 8, and is formed of a metal shaft and an elastic layer having an appropriate resistance value (1K to 10 GΩ). An appropriate voltage for transfer is applied to the metal shaft, and the toner image is transferred. Further, the transfer roller 12 is retracted so as not to contact the intermediate transfer member 5 while the toner image on the intermediate transfer member 5 is formed.

  Next, the intermediate transfer member 5 of the present invention will be described. FIG. 2 shows an enlarged cross-sectional view of the main part of the intermediate transfer member 5. The intermediate transfer member 5 is provided with an endless belt having flexibility so as to cover a cylindrical substrate 5a made of metal (aluminum or the like). The intermediate transfer member 5 has an elastic layer 5b made of polyurethane rubber having flexibility and elasticity as shown in FIG. 2, and an elastic layer 5b (polyurethane rubber) made of ozone is formed above and below the elastic layer 5b. A reinforcement / release layer 5c formed for preventing deterioration, reinforcing the mechanical strength of the belt, and improving the releasability of the surface is provided. Further, a surface layer 5d is provided on the surface by spray coating. Therefore, the intermediate transfer member 5 has a five-layer structure.

  By the way, the same effect can be obtained by using the intermediate transfer member 5 with the surface layer 5d applied to the surface of only the elastic layer 5b. Further, the elastic layer 5b can be made of chloroprene rubber, acrylic rubber, silicone rubber, nitrile rubber, hydrin rubber, fluorine rubber, etc., as long as it has flexibility and elasticity and mechanical properties meet the purpose. Depending on the purpose, one layer or two or more layers may be combined.

  Further, on the front surface, back surface, or both front and back surfaces of the elastic layer 5b, the elastic layer 5b is prevented from being deteriorated by ozone, the mechanical strength of the belt is strengthened, and the releasability is improved or the resistance value is adjusted. As the material of the mold layer 5c, a general material having flexibility such as a fluorine-based material, semiconductive plastic, polyethylene terephthalate, polyimide, or the like can be used. An intermediate transfer member using these can be produced by a known technique. Next, specific examples of the surface layer 5d will be described.

(Example 1)
Daiel Latex GLS-213 (A) (Daikin Kogyo Co., Ltd.) and Daiel Latex GLS-213 (B) (Daikin Kogyo Co., Ltd.) are placed on both sides of the elastic layer 5d made of polyurethane rubber (2 mm thick). After quantitative mixing and stirring, coating was performed with a spray gun, followed by natural drying, followed by baking at 170 ° C. for 1 hour to form a reinforcing / release layer 5c made of a fluorine-based material having a thickness of about 20 microns.

  Next, 4 parts by weight of an aminoalkylsilyl group-treated Aerosil RY-200H (manufactured by Nippon Aerosil Co., Ltd.), which is an inorganic material silica fine particle (average particle size 12 nm), and an oil-based material Silicone Oil KF54 (Shin-Etsu Chemical) 0.6 parts by weight) was dissolved in 85.4 parts by weight of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent, and ultrasonic dispersion was performed for about 2 hours. A coating solution for coating the surface was prepared. Using a spray gun, uniformly coat the surface of the reinforcing / release layer 5c so that the coating liquid has a ratio of 13 g / 1,000 cm 2, dry naturally, and dry at 110 ° C. for 1 hour. Then, a surface layer 5d having fine irregularities due to fine particles (silica) was formed on the surface to constitute a transfer belt. In the present embodiment, the content of fine particles in the surface layer 5d is 87% by weight.

FIG. 3 is an enlarged cross-sectional view schematically showing the state in the vicinity of the surface layer 5d. In the figure, 5e is a fine particle, 5f is a resin-based or oil-based material, and the surface is formed by the fine particle 5e and the resin-based or oil-based material 5f. A surface layer 5e having minute irregularities is formed on the surface of the reinforcing / releasing layer 5c.

  An image forming apparatus configured as shown in FIG. 1, using an intermediate transfer member 5 configured by mounting this transfer belt on a cylindrical substrate 5a as shown in FIG. 2, for example, a cut having a printing speed of 10 pages / min. A paper laser printer was prototyped. The relationship between the state of toner transferred to the image support (paper) using this, the occurrence of uneven transfer, the unevenness of image density, the image defect due to the void in the image such as characters and fine lines, the uneven thickness of the fine lines, etc. Was evaluated.

  The paper used is HINIP / HS paper (55 kg continuous paper: manufactured by Kobayashi Records Co., Ltd.) that is commonly used in printers.

  As a result of image evaluation, no image defects such as transfer unevenness, image density unevenness, and image dropout are generated from the initial stage, and a good image without uneven thickness of fine lines is obtained. The situation has not changed. Further, the prototype was modified for a printing speed of 60 pages / minute and the same test as described above was performed for 10,000 pages. However, the same problem as described above did not occur.

(Example 2)
A polyimide resin was used as the reinforcing / releasing layer 5c. As shown in FIG. 4 as a coating liquid to be applied to the surface, 4 parts by weight of Aerosil RY-200H (manufactured by Nippon Aerosil Co., Ltd.), an aminoalkylsilyl group-treated product that is silica fine particles (average particle size 12 nm), Disperse and dissolve 0.6 parts by weight of silicone oil KF968 (manufactured by Shin-Etsu Chemical Co., Ltd.) as an oil-based material in 85.4 parts by weight of toluene (manufactured by Wako Pure Chemical Industries, Ltd.), and ultrasonic dispersion is performed for 2 hours. The coating liquid was prepared. The coating liquid is uniformly coated with a spray gun so as to have a ratio of 20 g / 1,000 square cm. After natural drying, the coating liquid is dried at 110 ° C. for 1 hour and fine irregularities due to fine particles (silica) on the surface. A surface layer 5d having was formed. In the present embodiment, the content of fine particles in the surface layer 5d is 87% by weight. Then, the same evaluation experiment as in Example 1 was performed.

(Example 3)
As shown in FIG. 4, 2.5 parts by weight of dimethyldichlorosilane group-treated Aerosil R-972 (manufactured by Nippon Aerosil Co., Ltd.), which is silica fine particles (average particle size 16 nm), as a coating liquid, and a quaternary ammonium salt Charge control agent (average particle size 0.1 μm) LR-147 (made by Nippon Carlit Co., Ltd.) 2.0 parts by weight, silicone oil KF54 (made by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight, toluene (Wako Pure Chemical Industries, Ltd.) A coating solution was prepared by dispersing and dissolving in 85.1 parts by weight. The coating liquid is uniformly coated with a spray gun so as to have a ratio of 5 g / 1,000 square centimeters and dried to form a surface layer 5d having fine irregularities due to fine particles (silica fine particles and a charge control agent) on the surface. Formed. In this embodiment, the content of fine particles in the surface layer 5d is 92% by weight. Then, the same evaluation experiment as in Example 1 was performed.

Example 4
As a coating liquid, as shown in FIG. 4, 2.0 parts by weight of dimethyldichlorosilane group-treated Aerosil R-972 (manufactured by Nippon Aerosil Co., Ltd.), which is silica fine particles (average particle size 16 nm), and silicone oil KF54 ( 0.8 parts by weight (manufactured by Shin-Etsu Chemical Co., Ltd.) was dispersed and dissolved in 78.0 parts by weight of toluene and 6.2 parts by weight of ethanol to prepare a coating solution. This coating solution was uniformly coated with a spray gun so as to have a ratio of 3 g / 1,000 square cm, and dried to form a surface layer 5d having fine irregularities due to fine particles (silica fine particles) on the surface. In this embodiment, the content of fine particles in the surface layer 5d is 71% by weight. Then, the same evaluation experiment as in Example 1 was performed.

(Example 5)
As shown in FIG. 4, 4 parts by weight of an aminoalkylsilyl group-treated Aerosil RY-200H (manufactured by Nippon Aerosil Co., Ltd.), which is silica fine particles (average particle size 12 nm), and a silicone oil that is an oil-based material are used. A coating solution was prepared by dispersing and dissolving 0.6 parts by weight of KF968 (manufactured by Shin-Etsu Chemical Co., Ltd.) in 85.4 parts by weight of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent. The coating liquid was uniformly coated with a spray gun so as to have a ratio of 0.6 g / 1,000 square cm, and dried to form a surface layer 5d having fine irregularities due to fine particles (silica) on the surface. . In the present embodiment, the content of fine particles in the surface layer 5d is 87% by weight. Then, the same evaluation experiment as in Example 1 was performed.

(Example 6)
As shown in FIG. 4, 4 parts by weight of an aminoalkylsilyl group-treated Aerosil RY-200H (manufactured by Nippon Aerosil Co., Ltd.), which is silica fine particles (average particle size 12 nm), and a silicone oil that is an oil-based material are used. A coating solution was prepared by dispersing and dissolving 2.5 parts by weight of KF54 (manufactured by Shin-Etsu Chemical Co., Ltd.) in 83.5 parts by weight of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent. The coating liquid was uniformly coated with a spray gun so as to have a ratio of 1.5 g / 1,000 square cm and dried to form a surface layer 5d having fine irregularities due to fine particles (silica) on the surface. . In the present embodiment, the content of fine particles in the surface layer 5d is 62% by weight. Then, the same evaluation experiment as in Example 1 was performed.

(Example 7)
As shown in FIG. 4, 2.5 parts by weight of dimethyldichlorosilane group-treated Aerosil R-972 (manufactured by Nippon Aerosil Co., Ltd.), which is silica fine particles (average particle size 16 nm), as a coating liquid, and a quaternary ammonium salt Charge control agent (average particle size 0.1 μm) LR-147 (made by Nippon Carlit Co., Ltd.) 2.0 parts by weight, silicone oil KF54 (made by Shin-Etsu Chemical Co., Ltd.) 0.2 parts by weight, toluene (Wako Pure Chemical Industries, Ltd.) A coating solution was prepared by dispersing and dissolving in 85.3 parts by weight. The coating liquid is uniformly coated with a spray gun so as to have a ratio of 5 g / 1,000 square centimeters and dried to form a surface layer 5d having fine irregularities due to fine particles (silica fine particles and a charge control agent) on the surface. Formed. In the present example, the content of fine particles in the surface layer 5d is 96% by weight. Then, the same evaluation experiment as in Example 1 was performed.

(Example 8)
As shown in FIG. 4, 4.0 parts by weight of aluminum oxide fine particles having an average particle diameter of 13 nm (manufactured by Nippon Aerosil Co., Ltd.) and 1.2 parts by weight of silicone resin KR-216 (manufactured by Shin-Etsu Chemical Co., Ltd.) A coating solution was prepared by dispersing and dissolving in 84.8 parts by weight of toluene (manufactured by Wako Pure Chemical Industries, Ltd.). The coating solution was uniformly coated with a spray gun so as to have a ratio of 15 g / 1,000 square cm, and dried to form a surface layer 5d having fine irregularities due to fine particles (aluminum oxide) on the surface. In this embodiment, the content of fine particles in the surface layer 5d is 77% by weight. Then, the same evaluation experiment as in Example 1 was performed.

Example 9
As shown in FIG. 4, the coating liquid is 2.0 parts by weight of phthalocyanine (Clariant Japan) having an average particle size of 61 nm, which is a fine particle colorant, and styrene / acrylic resin Hammer ST-95 (manufactured by Sanyo Chemical Co., Ltd.). 0.8 parts by weight was dispersed and dissolved in 87.2 parts by weight of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) to prepare a coating solution. The coating solution was uniformly coated with a spray gun so as to have a ratio of 0.6 g / 1,000 square cm, and dried to form a surface layer 5d having fine irregularities due to fine particles (phthalocyanine) on the surface. In this embodiment, the content of fine particles in the surface layer 5d is 71% by weight. Then, the same evaluation experiment as in Example 1 was performed.

(Example 10)
As shown in FIG. 4, as a coating solution, 5.0 parts by weight of spherical silicon powder Tospearl 2000B (manufactured by Toshiba Silicon Co.) having an average particle size of 0.5 μm (classified product), which is a fine particle silicone material, and a silicone resin KR-216 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 part by weight, styrene / acrylic resin Himer ST-95 (manufactured by Sanyo Chemical Co., Ltd.) 0.3 part by weight, toluene 78.0 parts by weight and ethanol 6.2 A coating solution was prepared by dispersing and dissolving in parts by weight. The coating solution is uniformly coated with a spray gun so as to have a ratio of 1.5 g / 1,000 square cm, and dried to form a surface layer 5d having fine irregularities due to fine particles (silicone material) on the surface. did. The content of fine particles in the surface layer 5d in this example is 86% by weight. Then, the same evaluation experiment as in Example 1 was performed.

(Comparative Example 1)
An intermediate transfer member that does not form a surface layer was used.

(Comparative Example 2)
As shown in FIG. 4, 4 parts by weight of an aminoalkylsilyl group-treated product Aerosil RY-200H (manufactured by Nippon Aerosil Co., Ltd.), which is a silica fine particle (average particle size 12 nm), and toluene as a solvent (manufactured by Wako Pure Chemical Industries, Ltd.) ) Dispersed and dissolved in 86.0 parts by weight to prepare a coating solution. An oil-based material or a resin-based material having fine irregularities due to fine particles (silica) on the surface is obtained by coating the coating liquid with a spray gun so that the coating liquid has a ratio of 15 g / 1,000 square cm and drying. A free surface layer was formed. The content of fine particles in the surface layer in this comparative example is 100% by weight. Then, the same evaluation experiment as in Example 1 was performed.

(Comparative Example 3)
As shown in FIG. 4, 0.6 parts by weight of silicone oil KF54 (manufactured by Shin-Etsu Chemical Co., Ltd.) was dispersed and dissolved in 89.4 parts by weight of methyl ethyl ketone MEK (manufactured by Wako Pure Chemical Industries, Ltd.) to prepare a coating solution. . The coating solution was uniformly coated with a spray gun so as to have a ratio of 10 g / 1,000 square cm, and dried to form a surface layer of only an oil-based material containing no fine particles on the surface. The content of fine particles in the surface layer in this comparative example is 0% by weight. Then, the same evaluation experiment as in Example 1 was performed.

  FIG. 5 shows an initial image state and an image state after 1000 pages of the image forming apparatus (laser printer using a cut sheet having a printing speed of 10 pages / minute) in Examples 1 to 10 and Comparative Examples 1 to 3 of the present invention. FIG. 5 is a diagram comparing image states after 10,000 pages.

  As is apparent from this figure, the first to tenth embodiments of the present invention have no image quality disturbance from the beginning, have good image quality stability for a long time, and can obtain excellent image quality. In particular, even with continuous printing of 20000 pages in Example 1 and 10,000 pages in Examples 2, 6, and 10, there is no deterioration in image quality such as image distortion and excellent operation reliability over a long period of time.

On the other hand, in Comparative Example 1, since the intermediate transfer member is not provided with the surface layer as in the present invention, transfer is lost from the first sheet, density unevenness occurs, and image quality is disturbed at about 5000 pages. is there. In Comparative Example 2, since the surface layer is composed only of fine particles and there is no resin-based material or oil-based material, fine lines are non-uniform from the beginning and transfer omission occurs, and image quality is disturbed at about 4000 pages. In Comparative Example 3, the surface layer is composed only of an oil-based material and does not contain fine particles. Therefore, transfer loss and density unevenness occur from the initial stage, and image quality deterioration further progresses at about 1,000 pages, and about 10,000 pages. The image quality will be completely poor.

The coating method of the coating solution in the present invention is not limited to the spray method, and coating by the bar coater method or the like may be used as long as the coating solution can be uniformly applied to the transfer belt surface and uniform coating of fine particles is possible. In the preparation of the coating liquid used for coating, a known dispersant can be used as necessary as a fine particle dispersion aid.

  In other words, a resin or oily material that can be dissolved in a solvent is used to fix inorganic or organic fine particles as uniformly as possible on the surface of the intermediate transfer member to provide an appropriate gap between the surface of the intermediate transfer member and the toner, It is more desirable to use it in a design that maintains an appropriate adsorption force between them.

  The toner used in the present invention is blended with known toner resins, colorants, charge control agents, auxiliaries, etc., and is made into a toner by a known method, and further, to obtain desired properties for these toners, A combination of external additives can be used.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part of an intermediate transfer member according to an embodiment of the present invention. FIG. 3 is an enlarged schematic view of the vicinity of the surface layer of the intermediate transfer member. It is a figure which shows the coating liquid composition and coating liquid coating amount in Examples 1-10 of this invention, and Comparative Examples 1-3. It is a figure which compares and shows the image formation state in Examples 1-10 of this invention and Comparative Examples 1-3.

Explanation of symbols

1: belt-shaped photosensitive member, 2: charger, 3: exposure means, 4 (4a, 4b, 4c, 4d): developing means, 5: transfer member, 5a: cylindrical substrate, 5b: elastic layer, 5c: reinforcement Release layer, 5d: surface layer, 5e: fine particles, 5f: resin-based or oil-based material, 6: erase lamp, 7: photoconductor cleaning mechanism, 8: paper, 9: pickup roller, 10: charger before transfer, 11: Registration roller 11, 12: Transfer roller, 13: Static eliminator, 14: Fixing device, 15: Cleaning mechanism.

Claims (10)

In an intermediate transfer member used in an image forming apparatus for transferring a toner image on a surface of a photosensitive member having a photoconductor layer to an intermediate transfer member and transferring the toner image on the intermediate transfer member onto an image support to form an image. ,
A surface layer is formed on the surface of the intermediate transfer body to which the toner image is transferred, and the surface layer is at least fine particle silica, fine particle metal powder, fine particle colorant, fine particle charge control agent, or fine particle silicone type dispersible in a solvent. An intermediate transfer member comprising at least one material and at least one resin or oil-based material. 2. The intermediate transfer member according to claim 1, wherein at least one of the fine particle silica, the fine metal powder, the fine particle colorant, the fine particle charge control agent, and the fine particle silicone material is dispersed, and at least one of the resin or oil material is dispersed. An intermediate transfer member, wherein the solvent to be dissolved is an organic solvent. 3. The intermediate transfer member according to claim 1, wherein the fine particle silica, the fine particle metal powder, the fine particle colorant, the fine particle charge control agent, or the fine particle silicone material is the same type of material as that externally added to the toner surface. An intermediate transfer member characterized by The intermediate transfer member according to any one of claims 1 to 3, wherein the intermediate transfer member includes an endless substrate, an elastic layer provided on the endless substrate, and a surface provided on the elastic layer. And having a layer
A reinforcing / releasing layer between the elastic layer and the surface layer, between the elastic layer and the endless substrate, between the elastic layer and the surface layer, and between the elastic layer and the endless substrate. An intermediate transfer member, wherein: 5. The intermediate transfer member according to claim 4, wherein the reinforcing / release layer is made of a fluorine material or a polyimide material. 6. The intermediate transfer member according to claim 4, wherein a plurality of the reinforcing / release layers are formed. 2. The intermediate transfer member according to claim 1, wherein an average particle size of the fine particle silica, fine particle metal powder, fine particle colorant, fine particle charge control agent or fine particle silicone material is 1/10 of the toner particles forming the toner image. An intermediate transfer member characterized by the following: 2. The intermediate transfer member according to claim 1, wherein the content of the fine particles in the surface layer is regulated to a range of 60 to 97% by weight, and the weight of the surface layer is in a range of 0.5 g to 20 g per 1000 square cm. An intermediate transfer member characterized by being regulated by 2. The intermediate transfer member according to claim 1, wherein silica is used as fine particles of the surface layer and silicone oil is used as oil-based material, or silicon-based resin is used as fine particles and silicone-based resin is used as resin-based material. Intermediate transfer member. A photoconductor having a photoconductor layer, a charger for charging the surface of the photoconductor, exposure means for exposing the charged surface of the photoconductor based on image information to form an electrostatic latent image, and static A developing unit that visualizes the electrostatic latent image with toner, an intermediate transfer member that transfers the toner image on the surface of the photoreceptor, and a transfer device that transfers the toner image on the intermediate transfer member onto the image support. In the image forming apparatus,
An image forming apparatus, wherein the intermediate transfer member is the intermediate transfer member according to any one of claims 1 to 9.

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