JP2007310120A - Intermediate transfer body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transfer body having satisfactory secondary transferring performance even if many prints are prepared, free from the generation of damage and cracks on the surface and capable of obtaining a toner image of high quality having no unevenness in density. <P>SOLUTION: In the image forming apparatus where a toner image carried on an electrostatic latent image carrier is primarily transferred to an intermediate transfer body, and thereafter, the toner image is secondarily transferred from the intermediate transfer body to a recording member, the intermediate transfer body comprises at least either compound expressed by general formula (1) or general formula (2); wherein R<SB>1</SB>to R<SB>6</SB>denote a functional group selected from hydrogen, a halogen element, an alkyl group, an aryl group, an alkoxy group and an allyl group, and may be the same or different. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an intermediate transfer member.

  In recent years, electrophotographic image forming apparatuses capable of copying and printing full-color images have been put into practical use. In particular, as a method for transferring a full-color image to a recording member, a secondary transfer method using an intermediate transfer member is advantageous in terms of high-speed printability and full-surface copying, and is widely used.

  The secondary transfer method using an intermediate transfer body is a yellow (Y), magenta (M), cyan (C), or black (Bk) color image that is sequentially formed on an electrostatic latent image carrier such as a photoconductor. Are transferred onto the intermediate transfer member in a superimposed manner, and the transferred full-color toner images are transferred to a recording member in a lump, which is also called an intermediate transfer method.

As the intermediate transfer member, polycarbonate resin, PPS, thermoplastic resin, polyimide resin, polyamideimide resin, and the like are desired to be used, but sufficient secondary transferability could not be obtained in a high temperature and high humidity environment. As a solution to the above problem, improvement with an intermediate transfer member having a laminated structure has been attempted so far, and in particular, studies have been made on reducing the surface energy of the surface layer (see, for example, Patent Documents 1 to 4).
JP 2003-330216 A JP 2004-21188 A JP 2004-4504 A JP 2005-99182 A

  However, the intermediate transfer body having a laminated structure in which a surface layer mainly composed of a resin is provided on the base layer has improved the secondary transfer performance, but the surface of the intermediate transfer body is damaged when a large number of sheets are printed. And cracks occur, and when printing is performed, there is a problem that density unevenness occurs in the halftone area and a high-quality toner image cannot be obtained.

  An object of the present invention is to provide an excellent intermediate transfer member that has a good secondary transfer performance even when a large number of sheets are printed, does not cause scratches or cracks on the surface, and provides a high-quality toner image without density unevenness. .

  The present invention is achieved by adopting the following configuration.

1.
In the intermediate transfer body of the image forming apparatus, the toner image carried on the electrostatic latent image carrier is primarily transferred to the intermediate transfer body and then secondarily transferred from the intermediate transfer body to the recording member. An intermediate transfer member, wherein the body contains at least one of the compounds represented by formula (1) or formula (2).

(Wherein R _{1 to} R ₆ represent a functional group selected from hydrogen, a halogen element, an alkyl group, an aryl group, an alkoxy group, and an allyl group, and may be the same or different.)
2.
The intermediate transfer body has a laminated structure having a base material layer and a surface layer, and the surface layer contains at least one of the compounds represented by the general formula (1) or the general formula (2). The intermediate transfer member according to 1.

(Wherein R _{1 to} R ₆ represent a functional group selected from hydrogen, a halogen element, an alkyl group, an aryl group, an alkoxy group, and an allyl group, and may be the same or different.)
3.
3. The intermediate transfer member according to item 1 or 2, wherein the main component of the surface layer is a curable resin that is cured by heat or light.

4).
4. The intermediate transfer member according to any one of items 1 to 3, wherein the curable resin is an acrylic resin.

  The intermediate transfer member of the present invention has excellent secondary transfer performance even when a large number of sheets are printed, and has an excellent effect of obtaining a high-quality toner image without causing scratches or cracks on the surface and without density unevenness.

  The present inventors have studied an intermediate transfer body that has a good secondary transfer performance even when a large number of sheets are printed, does not cause scratches or cracks on the surface, and provides a high-quality toner image without density unevenness.

  As a result of various studies, when an image is formed by using an intermediate transfer member containing a compound having a reversible redox function in the coating film, the secondary transfer performance is good even when a large number of sheets are printed, and the surface is scratched. It has been found that cracks can be prevented from occurring.

  In particular, with regard to secondary transferability, an intermediate transfer body in which a surface layer containing a compound having a reversible redox function is provided on a base material layer and the surface layer has a high hardness reduces deformation due to pressing. Therefore, when transferring the toner image from the intermediate transfer member to the secondary transfer member, the intermediate transfer member can be prevented from being deformed even if a transfer pressure is applied. For this reason, it is considered that good secondary transferability can be obtained.

  In addition, it is considered that the compound having a reversible redox function can maintain the secondary transfer rate in a long term and can prevent generation of scratches and cracks because it suppresses oxidative degradation.

  Furthermore, as a result of various investigations to obtain an intermediate transfer body that has good transferability and does not cause scratches or cracks on the surface, it is cured by heat or light mainly composed of epoxy resin, silicone resin, acrylic resin, etc. It has been found that the mold resin is preferable for obtaining an intermediate transfer body having good secondary transfer properties and no scratches or cracks on the surface. Among these resins, curable acrylic resins were particularly preferred.

  The reason why curable acrylic resins give good results is that they have better compatibility with various constituent materials that make up the surface layer compared to other resins, This is probably because the uniform dispersibility is excellent.

  It is preferable to irradiate the surface layer formed of a curable acrylic resin with ultraviolet rays to cure the surface layer and to increase the hardness and further improve the secondary transferability.

  The present invention will be described below.

<< Compounds Represented by General Formula (1) and General Formula (2) >>
The compounds represented by the following general formula (1) and general formula (2) used in the present invention will be described.

(Wherein R _{1 to} R ₆ represent a functional group selected from hydrogen, a halogen element, an alkyl group, an aryl group, an alkoxy group, and an allyl group, and may be the same or different.)
Specific examples of the compounds represented by the general formula (1) and the general formula (2) include p-methoxyphenol, hydroquinone, alkyl and aryl substituted hydroquinone and quinone, tert-butylcatechol, pyrogallol, copper resinate, β-naphthol. 2,6-di-tert-butyl-p-cresol, 2,2′-methylenebis (4-ethyl-) 6-t-bibutylphenol, p-tolylquinone, chloranil and the like.

  These compounds are preferably contained in an amount of 10 to 10000 ppm, more preferably 100 to 2000 ppm based on the total mass of the layer containing these compounds.

<Layer structure of intermediate transfer member>
The intermediate transfer member of the present invention may be composed of only a base material layer, but may be of a two-layer structure in which a surface layer is provided on the base material layer. Furthermore, the thing of the 3 layer structure which provided the intermediate | middle layer between the base material layer and the surface layer may be used.

  FIG. 1 is a schematic view showing an example of the intermediate transfer member of the present invention.

  In FIG. 1, 2 is an intermediate transfer member, 21 is a surface layer, 23 is a base material layer, and 24 is an intermediate layer.

  The intermediate transfer member 2 shown in FIG. 1 is preferably endless. The intermediate transfer member 2 shown in FIG. 1A has a single-layer structure consisting only of the base material layer 23. The intermediate transfer member 2 shown in FIG. 1B has a two-layer structure in which a surface layer 21 is provided on a base material layer 23. The intermediate transfer member 2 shown in FIG. 1C has a three-layer structure in which an intermediate layer 24 is provided outside the base material layer 23 and a surface layer 21 is provided outside the intermediate layer 24.

  Hereinafter, an intermediate transfer member having a two-layer structure of a base material layer and a surface layer will be described.

<Base material layer>
The base material layer has rigidity that avoids deformation of the belt due to a load applied to the intermediate transfer member including the cleaning blade and reduces the influence on the transfer portion. The base material layer is preferably formed using a material having a Young's modulus of 200 MPa or more, and more preferably a material of 300 MPa or more.

  Examples of materials that exhibit such performance include resin materials such as polycarbonate, polyvinylidene fluoride (PVDF), polyimide, and (PEEK) polyether ether ketone (PEEK). These resin materials have a Young's modulus exceeding 200 MPa, have a thickness of 100 to 150 μm, and satisfy the mechanical properties as a belt base material.

  The material used for the base layer is, for example, a resin material such as polyimide, polyester, polyetheretherketone, polyamide, polycarbonate, polyvinylidene fluoride (PVDF), polyfluoroethylene-ethylene copolymer (ETFE), and the like. Resin materials mainly composed of these materials are listed. Furthermore, it is also possible to use a material obtained by blending the aforementioned fat material and elastic material. Examples of the elastic material include polyurethane, chlorinated polyisoprene, NBR, chloropyrene rubber, EPDM, hydrogenated polybutadiene, butyl rubber, and silicone rubber. These may be used alone or in combination of two or more.

  Among these, it is preferable to contain a polyimide resin. The polyimide resin is formed by heating polyamic acid that is a precursor of the polyimide resin. The polyamic acid can be obtained by dissolving tetracarboxylic dianhydride or an approximately equimolar mixture of its derivative and diamine in an organic polar solvent and reacting in a solution state.

  In addition, when a material in which carbon black is dispersed in a polybiphenyltetracarboxylic imide-based resin material such as Upilex S manufactured by Ube Industries, Ltd. is used as the base material of the intermediate transfer member of the present invention, the Young's modulus of the material is used. Is 200 MPa or more, and a belt thickness of 70 to 100 μm can satisfy the mechanical properties as a belt substrate.

  In addition, in this invention, when using polyimide-type resin for a base material layer, it is preferable that the content rate of the polyimide-type resin in a base material layer is 51% or more.

<Surface layer>
The resin constituting the surface layer is preferably a resin that is cured by heat or light.

  Examples of the resin curable by heat or light include ultraviolet (UV) curable acrylic resin, thermosetting silicone, ultraviolet curable silicone, and fluorine elastomer. Among these, UV curable acrylic resin is particularly preferable.

  Specific examples of the ultraviolet (UV) cured acrylic resin include a cured (meth) acrylic resin, and the surface layer of the cured (meth) acrylic resin starts polymerization with, for example, a (meth) acrylic monomer or oligomer. After forming the coating layer containing the agent, it can be obtained by irradiating with ultraviolet rays.

The cured acrylic monomer or oligomer is a compound having a plurality of acryloyloxy groups (CH ₂ ═CHCOO—) or methacryloyloxy groups (CH ₂ ═C (CH ₃ ) COO—).

  If the example of a typical compound is given, the thing of the following structure can be mentioned.

  Examples of the polymerization initiator for the ultraviolet curable resin include benzophenone, Michler ketone, 1-hydroxycyclohexyl-phenyl ketone, thioxanthone, benzobutyl ether, acyloxime ester, dibenzothroben, bisacylphosphine oxide and the like.

  The surface layer can be formed by adding an additive such as a conductive material, a resistance adjusting agent such as an inorganic filler, if necessary.

  The characteristics of the surface layer are affected by the type of UV curable acrylic monomer or oligomer, its composition ratio, UV curing conditions, and the like.

  That is, the intermediate transfer member surface layer is preferably a resin prepared by reacting a monomer having a bifunctional or higher functional group with a cured (meth) acrylic resin to be formed. Mainly composed of a resin formed by reacting a monomer having a monomer and a cured (meth) acrylic acid having an alkyl group having 12 or more carbon atoms, or a resin formed by reacting with a bifunctional oligomer When it is contained, it exhibits particularly good characteristics.

<Preparation of intermediate transfer member>
The method for producing the intermediate transfer member is not particularly limited. For example, each layer forming material and its solvent are appropriately blended, and kneaded and stirred with a ball mill or the like to prepare each coating solution. The concentration of the coating solution thus prepared is appropriately set according to the layer thickness. Next, each coating solution is accommodated in a tank, and on the other hand, a shaft made of metal such as aluminum or stainless steel is prepared, and this shaft is vertically placed in a tank in which the coating liquid for the base material layer is accommodated. Put in a standing condition and immerse. At this time, after dipping is repeated several times to form a coating film having a predetermined thickness, the shaft body is pulled up from the coating solution. Subsequently, the same operation is repeated using the coating liquid of each layer to form a multilayer structure. Next, after drying and removing the solvent, heat treatment (for example, 60 to 150 ° C. × 60 minutes) and ultraviolet irradiation are performed, and the shaft body is extracted to produce the endless intermediate transfer member shown in FIG.

  In addition to this dipping method, an intermediate transfer member can be produced by methods such as extrusion molding, spray coating, inflation, and blow molding.

  When forming an endless (seamless) base material layer, for example, a method in which a polyamic acid solution is immersed in the outer peripheral surface of a cylindrical mold, a method in which the polyamic acid solution is applied to the inner peripheral surface, a method in which centrifugation is further performed, or a casting mold It is developed into a ring shape by an appropriate method such as a method of filling in, and the developed layer is dried and formed into a bell-shaped shape, and the molded product is heat-treated to convert the polyamic acid into an imide from the mold. It can be carried out by an appropriate method according to the conventional method such as a recovery method (JP-A 61-95361, JP-A 64-22514, JP-A 3-180309, etc.). In forming the seamless belt, an appropriate treatment such as mold release treatment or defoaming treatment can be performed.

  When forming the surface layer on the base material layer, the surface layer coating solution is spray-coated on the base material layer to form a coating film, and after the primary drying to the extent that the fluidity of the coating film is lost, In order to cure the resin by curing or irradiating with ultraviolet rays, and to make the amount of volatile substances in the coating film a prescribed amount, a method of performing secondary drying is preferable.

<Image forming apparatus>
Next, an image forming apparatus that can use the intermediate transfer member of the present invention will be described.

  Examples of the image forming apparatus capable of using the intermediate transfer member of the present invention include a copying machine and a laser printer. In particular, an image forming apparatus capable of continuous printing of 5000 sheets or more is preferably used. In such an apparatus, an electric field is easily generated between the intermediate transfer member and the recording medium because a large amount of printing is performed in a short time, but the generation of the electric field is suppressed and stable by the intermediate transfer member of the present invention. Secondary transfer can be performed.

  An image forming apparatus used in the present invention includes an image carrier that forms an electrostatic latent image according to image information, a developing device that forms a toner image by developing the electrostatic latent image formed on the image carrier, and an image A primary transfer unit that transfers the toner image on the carrier onto the intermediate transfer member; and a secondary transfer unit that transfers the toner image on the intermediate transfer member onto a recording medium such as paper or an OHP sheet. By using the intermediate transfer member of the present invention as an intermediate transfer member, stable toner image formation can be performed without causing peeling discharge during secondary transfer.

  The image forming apparatus used in the present invention includes a monochrome image forming apparatus that forms an image with a single color toner, a color image forming apparatus that sequentially transfers a toner image on an image carrier to an intermediate transfer body, and a plurality of images for each color. Examples thereof include a tandem color image forming apparatus in which a carrier is arranged in series on an intermediate transfer member.

  FIG. 2 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus in which the intermediate transfer member of the present invention can be used.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7 as a transfer unit, and a recording member P. An endless belt-shaped sheet feeding and conveying means 21 and a belt type fixing device 24 as a fixing means. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  As one of the different color toner images formed on each photoconductor, an image forming unit 10Y that forms a yellow image includes a drum-shaped photoconductor 1Y as a first image carrier, and the photoconductor 1Y. A charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roller 5Y as a primary transfer unit, and a cleaning unit 6Y are arranged around the periphery. In addition, an image forming unit 10M that forms a magenta image as another different color toner image is a drum-shaped photoconductor 1M as a first image carrier, and is arranged around the photoconductor 1M. The charging unit 2M, the exposure unit 3M, the developing unit 4M, the primary transfer roller 5M as the primary transfer unit, and the cleaning unit 6M are included. In addition, an image forming unit 10C that forms a cyan image as another different color toner image includes a drum-shaped photoconductor 1C as a first image carrier, and around the photoconductor 1C. A charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, and a cleaning unit 6C are disposed. In addition, an image forming unit 10K that forms a black image as one of other different color toner images is disposed around a drum-shaped photoconductor 1K as a first image carrier and the photoconductor 1K. A charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer roller 5K as a primary transfer unit, and a cleaning unit 6K.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rollers 5Y, 5M, 5C, and 5K, and is combined. A colored image is formed. A recording member P such as paper as a recording medium accommodated in the paper feeding cassette 20 is fed by the paper feeding / conveying means 21, passes through a plurality of intermediate rollers 22 A, 22 B, 22 C, 22 D, and registration rollers 23, and is secondary. A color image is transferred onto the recording member P at a time by being conveyed to a secondary transfer roller 5A as a transfer means. The recording member P to which the color image has been transferred is fixed by the belt-type fixing device 24, is sandwiched between the discharge rollers 25, and is placed on the discharge tray 26 outside the apparatus.
The residual toner is removed from the endless belt-shaped intermediate transfer member 70 separated by the curvature by the cleaning means 6A.

  During the image forming process, the primary transfer roller 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rollers 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5A comes into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the recording member P passes through the secondary transfer roller 5A and secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10K, and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, and 76, primary transfer rollers 5Y, 5M, 5C, and 5K, and a cleaning unit. 6A.

  The image forming units 10Y, 10M, 10C, and 10K and the endless belt-shaped intermediate transfer body unit 7 are integrally pulled out from the main body A by the drawer operation of the housing 8.

  In this manner, toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer body 70, and are collectively applied to the recording member P. The image is transferred and fixed by a belt-type fixing device 24 by pressing and heating. The photoreceptors 1Y, 1M, 1C, and 1K after transferring the toner image to the recording member P are cleaned with the cleaning device 6A to remove the toner remaining on the photoreceptor, and then the above-described charging, exposure, and development cycle. The next image formation is performed.

<Recording member>
The recording member used in the present invention is a support for holding a toner image, and is usually called an image support, a transfer material or a transfer paper. Specific examples include various types of transfer materials such as plain paper from thin paper to thick paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, plastic films for OHP, and cloth. However, it is not limited to these.

  The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these examples.

[Preparation of intermediate transfer member]
<Preparation of base material layer 1>
N-methyl-2-, a polyamic acid composed of “Euvanis S” (3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA): manufactured by Ube Industries) and p-phenylenediamine (PDA) To 100 parts by mass of a solid content of pyrrolidone (NMP) 18% by mass, 23 parts by mass of a conductive agent “T-1” (solid content 20% by mass: Mitsubishi Materials) and 0.1 part by mass of hydroquinone were added. Using a collision-type disperser “GeanusPY” (manufactured by Seanas), the pressure is 200 MPa, the minimum area is 1.4 mm ² , and the collision is performed after two divisions. A polyamic acid solution containing a conductive agent for the material layer was prepared.

  The polyamic acid solution containing the conductive agent for the base material layer prepared above is applied to the inner surface of the cylindrical mold to a thickness of 0.5 mm via a dispenser, and rotated at 1500 rpm for 15 minutes to have a uniform thickness. After forming a layer, hot air at 60 ° C. was applied for 30 minutes from the outside of the mold while rotating at 250 rpm, and then heated at 150 ° C. for 60 minutes. Thereafter, the temperature was raised to 360 ° C. at a rate of 2 ° C./min, and further heated at 360 ° C. for 30 minutes to remove the solvent, remove dehydrated ring-closing water, and complete the imide conversion reaction. Thereafter, the temperature was returned to room temperature, and the mold was peeled from the mold to produce an endless belt-shaped “base material layer 1”. The total thickness of this base material layer was 100 μm.

<Preparation of base material layer 2>
“Base material layer 2” was prepared in the same manner except that the added “hydroquinone” was not added.

<< Preparation of Intermediate Transfer Member 1 >>
<Formation of surface layer 1>
The following surface layer coating composition was mixed and stirred to prepare a surface layer coating solution.

Coating composition for surface layer Silicone resin “X22-2269” (manufactured by Shin-Etsu Chemical Co., Ltd.) 100 parts by mass Conductive inorganic particles “T-1” (solid content concentration 20%: manufactured by Mitsubishi Materials Corporation) 50 parts by mass Hydroquinone "0.01 parts by weight Solvent" MIBK / MEK (8/2) "1500 parts by weight This coating solution is spray-coated on the" substrate layer 2 "prepared above, and then in an oven at 150 ° C for 60 minutes. Drying was performed to form “Surface Layer 1” mainly composed of thermosetting silicone, and “Intermediate Transfer Member 1” was produced.

<< Preparation of Intermediate Transfer Member 2 >>
<Formation of surface layer 2>
The following surface layer coating composition was mixed and stirred to prepare a surface layer coating solution.

Coating composition for surface layer UV curable silicone hard coating agent “X12-2450” (manufactured by Shin-Etsu Chemical Co., Ltd.)
100 parts by mass Polymerization initiator “Irgacure 184” (manufactured by Ciba Specialty Chemicals)
1 part by weight Conductive inorganic particles “T-1” (solid content concentration 20%: manufactured by Mitsubishi Materials Corporation) 50 parts by weight Additive “hydroquinone” 0.01 part by weight Solvent “MIBK / MEK (8/2)” 1500 parts by weight Part This coating solution is spray-coated on the “substrate layer 1” produced above, and then primary drying is performed in an oven at 30 ° C. for 30 minutes, and then 2000 mJ / cm with a mercury lamp having an ultraviolet intensity of 1 kW / cm ^2. Curing was performed by irradiating ² accumulated light amounts to form “Surface Layer 2” containing UV-cured silicone as a main component, and “Intermediate Transfer Member 2” was produced.

<< Preparation of Intermediate Transfer Member 3 >>
<Formation of surface layer 3>
The following surface layer coating composition was mixed and stirred to prepare a surface layer coating solution.

Coating composition for surface layer Acrylic monomer “KAYARAD DPHA” (manufactured by Nippon Kayaku Co., Ltd.) 100 parts by mass Polymerization initiator “Irgacure 184” (manufactured by Ciba Specialty Chemicals)
1 part by mass Conductive inorganic particles “Selnax CX-Z210IP” (solid content concentration 20%: manufactured by Nissan Chemical Co., Ltd.) 50 parts by mass Additive “hydroquinone” 0.01 part by mass Solvent “MIBK / MEK (8/2)” 1500 parts by weight This coating solution is spray-coated on the above-prepared “Base Layer 2”, followed by primary drying in an oven at 30 ° C. for 30 minutes, and then 2000 mJ with a mercury lamp with an ultraviolet intensity of 1 kW / cm ^2. Curing was performed by irradiating a cumulative amount of light of / cm ² to form “surface layer 3” containing UV-cured acrylic as a main component, and “intermediate transfer body 3” was produced.

<< Preparation of Intermediate Transfer Member 4 >>
In the production of the intermediate transfer member 3, the “intermediate transfer member 4” containing UV-cured acrylic as a main component is prepared in the same manner except that the additive “hydroquinone” is changed to “p-methoxyphenol” (manufactured by Kanto Chemical Co., Inc.). did.

<< Preparation of Intermediate Transfer Member 5 >>
In the production of the intermediate transfer member 1, an “intermediate transfer member 5” containing thermosetting silicone as a main component was produced in the same manner except that the additive “hydroquinone” was not added.

<< Preparation of Intermediate Transfer Member 6 >>
An “intermediate transfer member 6” was prepared in the same manner as in the preparation of the intermediate transfer member 1 except that the silicone resin “X22-2269” was changed to a liquid fluoroelastomer “SIFEL601” (manufactured by Shin-Etsu Chemical Co., Ltd.).

<< Preparation of Intermediate Transfer Member 7 >>
The “intermediate transfer member 7” was prepared by providing only the “base layer 2” without providing a surface layer.

<< Preparation of Intermediate Transfer Member 8 >>
The “intermediate transfer member 8” was obtained by providing only the “base layer 1” without providing the surface layer.

  Table 1 shows the resin and compound (transfer agent) additive used for preparing the base material layers of the intermediate transfer members 1 to 8 and the resin and compound (additive) used for preparing the surface layer.

[Evaluation]
The “intermediate transfer members 1 to 8” produced above were mounted on “bizhub C250” manufactured by Konica Minolta Business Technologies, Inc. for evaluation.

For image formation, a two-component developer comprising a toner having a median diameter (D ₅₀ ) of 4.5 μm on the basis of number and a coat carrier of 60 μm was used.

  The printing environment was high temperature and high humidity (33 ° C., 80% RH) and low temperature and low humidity (10 ° C., 20% RH). A4 size fine paper was used as the recording medium. The printed document used was a character image, a color halftone image, a solid white image, and an image in which the solid image is divided into ¼ equal parts, respectively, for each of yellow, magenta, cyan, and black.

  The following items were evaluated for image evaluation and evaluation of the appearance of the intermediate transfer member. The evaluation criteria are ◎ and ○ are acceptable, and × is unacceptable due to practical problems.

<Transfer rate>
Initially and after the end of printing 10,000 sheets (after endurance), a solid image (20 mm × 50 mm) having a pixel density of 1.30 was formed at a low temperature and low humidity, and the transfer rate was determined by the following formula and evaluated.

Transfer rate (%) = (mass of toner transferred to recording member / mass of toner on intermediate transfer member) × 100
Evaluation Criteria A: Good when the transfer rate is 95% or more B: Practical problem when the transfer rate is 90% or more and less than 95% ×: Level where the transfer rate is less than 90% and causes a practical problem.

<Scratch occurrence>
After the completion of printing 10,000 sheets in a high-temperature and high-humidity environment (33 ° C., 80% RH), the state of scratches on the surface of the intermediate transfer member was visually evaluated.

A: There are no visible scratches. O: There are two visible scratches. X: There are three or more visible scratches.

<Occurrence of cracks>
After completion of printing 10,000 sheets in a high temperature and high humidity environment (33 ° C., 80% RH), the occurrence of cracks on the surface of the intermediate transfer member was visually evaluated.

◎: No cracking occurred. ○: One crack occurred. ×: Two or more cracks occurred.

<Density unevenness>
Print 10,000 sheets in a high-temperature and high-humidity environment (33 ° C, 80% RH), and visually check for uneven density in the halftone image area corresponding to the scratches or cracks on the surface of the intermediate transfer body of the 10,000th printed image. Observed and evaluated ◎: No density unevenness in the halftone image part due to scratches or cracks ○: Level of density unevenness in the halftone image part due to scratches or cracks within practically no problem within 2 places ×: Scratches or There are three or more density irregularities in the halftone image area due to cracks, which is a practical problem.

  Table 2 shows the evaluation results.

  As shown in Table 2, the intermediate transfer members 1 to 6 and 8 corresponding to the present invention showed good results in transfer rate, scratches, cracks, and density unevenness, whereas Comparative Example 1 outside the present invention, It was confirmed that the intermediate transfer members 5 and 7 of No. 2 had problems in any of these evaluation items, and the effects of the present invention were not exhibited.

FIG. 3 is a schematic diagram illustrating an example of an intermediate transfer member of the present invention. 1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus that can use an intermediate transfer member of the present invention.

Explanation of symbols

2 Intermediate transfer member 21 Surface layer 23 Base material layer 24 Intermediate layer

Claims (4)

In the intermediate transfer body of the image forming apparatus, the toner image carried on the electrostatic latent image carrier is primarily transferred to the intermediate transfer body and then secondarily transferred from the intermediate transfer body to the recording member. An intermediate transfer member, wherein the body contains at least one of the compounds represented by formula (1) or formula (2).

(Wherein R _{1 to} R ₆ represent a functional group selected from hydrogen, a halogen element, an alkyl group, an aryl group, an alkoxy group, and an allyl group, and may be the same or different.) The intermediate transfer member has a laminated structure having a base layer and a surface layer, and the surface layer contains at least one of the compounds represented by the general formula (1) or the general formula (2). Item 4. The intermediate transfer member according to Item 1.

(Wherein R _{1 to} R ₆ represent a functional group selected from hydrogen, a halogen element, an alkyl group, an aryl group, an alkoxy group, and an allyl group, and may be the same or different.) The intermediate transfer member according to claim 1 or 2, wherein a main component of the surface layer is a curable resin that is cured by heat or light. The intermediate transfer member according to claim 1, wherein the curable resin is an acrylic resin.

Images