JP2001166616A - Transfer member for image forming device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer member-which consists of a polyurethane foam and is improved in cleanable property. SOLUTION: This transfer member for image forming device is formed by coating a member consisting of the polyurethane foam formed by using polyol and polyisocyanate as main raw materials with a coating material consisting of an aqueous emulsion of polyurethane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer member of an image forming apparatus used in an electrophotographic apparatus such as a copying machine, a facsimile, a printer or the like, or an electrostatic recording apparatus, and an image forming apparatus equipped with this member. It is.

[0002]

2. Description of the Related Art In recent years, with the progress of electrophotographic technology, polyurethane foam members have attracted attention as members used for transfer in image forming apparatuses such as dry electrophotographic apparatuses.
It is used in the form of an elastic roller such as a transfer roller. The transfer member is a member for transferring a developer such as a toner from an image carrier such as a photoconductor or an intermediate transfer material to a recording medium such as plain paper, and is required to have predetermined hardness and electrical characteristics. Therefore, it is preferable to apply a polyurethane foam containing conductive particles such as an electrolyte and carbon black. Polyurethane is produced by reacting and curing a liquid polyisocyanate component and a liquid polyol component. As a method for forming a polyurethane foam, a method of mechanically stirring gas while blowing a gas such as nitrogen gas during the reaction curing (mechanical floss method), adding water to a polyol component, and adding water and a polyisocyanate component (Water foaming method), a low boiling point liquid such as chlorofluorocarbons and low boiling point hydrocarbons is added to a polyol component, and the low boiling point liquid is vaporized due to a rise in temperature during reaction curing. (Blowing agent floss method). In order to manufacture a transfer member such as a roller made of polyurethane foam by the mechanical floss method, a polyurethane material is placed in advance with a metal shaft, and the preheated inner surface is foamed into a cylindrical metal mold by mechanical stirring. May be cast and reacted and cured. Alternatively, a polyurethane raw material may be cast into a metal mold, and the mixture may be cured by mechanical stirring. To manufacture a transfer member such as a roller made of polyurethane foam by a water foaming method, first, for example, a polyurethane material is poured into a mold having an inner dimension of 1 m × 1 m × 1 m to a height of about 0.1 m, and this material is foamed. The polyurethane foam block having a size of about 1 m × 1 m × 1 m is obtained by swelling and expanding and curing. Next, the obtained block is cut into a predetermined size, a hole is formed, a shaft is press-fitted, and a transfer member such as a roller is manufactured through a process such as cutting or polishing. In addition, the blowing agent floss method using fluorocarbons is a method for protecting the ozone layer, and the blowing agent floss method using low-boiling hydrocarbons is preferable from the viewpoint of hazardous material management in a manufacturing plant. It is not used in the production of polyurethane foam.

[0003]

However, when the transfer member thus manufactured is mounted on an image forming apparatus and used, it remains without being transferred onto an image carrier such as a photoreceptor or an intermediate transfer member. It is said that the developer such as toner adheres to the surface of the transfer member, and the adhered developer deteriorates during use of the transfer member for a long period of time and contaminates the surface of the image carrier, thereby causing an image defect. There was a problem. As a method for solving this problem, a method for mounting a member for cleaning the image carrier to the image forming apparatus, a method for mounting a member for cleaning the transfer member itself to the image forming apparatus, or an operation of the image forming apparatus Although a method of incorporating a process for cleaning the transfer member into the process has been proposed, development of a method for further improving the cleaning property of the transfer member itself has been desired. The present invention
In view of the above circumstances, a transfer member made of a polyurethane foam and having improved cleaning properties is provided while maintaining the characteristic of having a predetermined electrical property at a predetermined hardness, which is a characteristic of a transfer member made of a polyurethane foam. It is intended to do so.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above-mentioned object, and as a result, have found that a transfer member of an image forming apparatus comprising a polyurethane foam formed using polyol and polyisocyanate as main raw materials. It has been found that the above object can be effectively achieved by applying a coating composed of an aqueous emulsion of polyurethane to lower the surface tackiness of the transfer member. The present invention has been completed based on such findings. That is, the present invention provides a transfer member of an image forming apparatus, characterized in that a member made of a polyurethane foam produced using a polyol and a polyisocyanate as main raw materials is coated with a coating material comprising an aqueous emulsion of polyurethane. Is provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A transfer member of an image forming apparatus according to the present invention is made of a polyurethane foam produced using polyol and polyisocyanate as main raw materials. As the polyisocyanate constituting the polyurethane raw material, an aromatic isocyanate or a derivative thereof, an aliphatic isocyanate or a derivative thereof, and an alicyclic isocyanate or a derivative thereof are used. Of these, aromatic isocyanates or derivatives thereof are preferable, and tolylene diisocyanate or derivatives thereof, diphenylmethane diisocyanate or derivatives thereof are particularly preferably used. Examples of tolylene diisocyanate or a derivative thereof include crude tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, Urea-modified, buret-modified, carbodiimide-modified, urethane-modified products modified with polyols and the like are used. As diphenylmethane diisocyanate or its derivative, for example, diphenylmethane diisocyanate or its derivative obtained by phosgenating diaminodiphenylmethane or its derivative is used. Examples of the derivative of diaminodiphenylmethane include polynuclear substances, such as pure diphenylmethane diisocyanate obtained from diaminodiphenylmethane, and polymeric diphenylmethane diisocyanate obtained from a polynuclear substance of diaminodiphenylmethane. As for the number of functional groups of polymeric diphenylmethane diisocyanate, a mixture of pure diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate having various functional groups is used, and the average number of functional groups is preferably 2.05 to 4.00, more preferably 2. Those having 50 to 3.50 are used. Derivatives obtained by modifying these diphenylmethane diisocyanates or derivatives thereof, for example, urethane modified products modified with polyols and the like, dimers formed by uretidione formation,
Modified isocyanurate, modified carbodiimide / uretonimine, modified allohanate, modified urea, modified buret, and the like can also be used. In addition, several kinds of diphenylmethane diisocyanates and derivatives thereof can be used by blending.

[0006] Polyol components constituting polyurethane raw materials include polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide, polytetramethylene ether glycol, polyester polyol obtained by condensing an acid component and a glycol component, and caprolactone by ring-opening polymerization. Polyester polyol, polycarbonate diol and the like can be used. Polyether polyols obtained by addition polymerization of ethylene oxide and propylene oxide include, for example, water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, methylglucode, Starting materials are aromatic diamines, sorbitol, sucrose, phosphoric acid, and the like, and examples of addition polymerization of ethylene oxide and propylene oxide include water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, and the like. Those using hexanetriol as a starting material are preferred. Regarding the ratio of ethylene oxide to propylene oxide and the microstructure to be added, the ratio of ethylene oxide is preferably from 2 to 95% by weight, more preferably from 5 to 90% by weight. Those having ethylene oxide added to the terminal are preferably used. Also, the arrangement of ethylene oxide and propylene oxide in the molecular chain is preferably random. The molecular weight of the polyether polyol is bifunctional when water, propylene glycol or ethylene glycol is used as a starting material, and is preferably in the range of 300 to 6000 in weight average molecular weight, particularly preferably in the range of 400 to 3000. . When glycerin, trimethylolpropane, or hexanetriol is used as a starting material, it is trifunctional and preferably has a weight average molecular weight in the range of 900 to 9000, particularly preferably 1500 to 6000. Further, a bifunctional polyol and a trifunctional polyol can be appropriately blended and used.

The polytetramethylene ether glycol is obtained, for example, by cationic polymerization of tetrahydrofuran, and those having a weight average molecular weight of 400 to 4000, particularly preferably 650 to 3000 are preferably used. It is also preferable to blend polytetramethylene ether glycols having different molecular weights. Furthermore, polytetramethylene ether glycol obtained by copolymerizing an alkylene oxide such as ethylene oxide or propylene oxide can also be used. It is also preferable to use a blend of polytetramethylene ether glycol and a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide.In this case, polytetramethylene ether glycol, addition polymerization of ethylene oxide and propylene oxide are used. The ratio with the polyether polyol is 95:
It is preferably used in a range of 5 to 20:80, and particularly preferably in a range of 90:10 to 50:50. Further, together with the polyol component, a polymer polyol obtained by modifying the polyol with acrylonitrile, a polyol obtained by adding melamine to the polyol, a diol such as butanediol, a polyol such as trimethylolpropane, or a derivative thereof can be used in combination.

The polyol may be pre-polymerized with a polyisocyanate in advance. The method is as follows. The polyol and the polyisocyanate are put in an appropriate container, sufficiently stirred, and kept at 30 to 90 ° C., more preferably 40 to 90 ° C.
~ 70 ° C for 6-240 hours, more preferably 24-7
There is a method of keeping the temperature for 2 hours. In this case, the ratio of the amounts of polyol and polyisocyanate is preferably adjusted so that the isocyanate content of the obtained prepolymer is 4 to 30% by weight, more preferably 6% by weight.
１５15% by weight. If the content of the isocyanate is less than 4% by weight, the stability of the prepolymer may be impaired, and the prepolymer may be cured during storage and may not be usable. On the other hand, when the isocyanate content exceeds 30% by weight, the content of the non-prepolymerized polyisocyanate increases, and the polyisocyanate reacts with the polyol component used in the subsequent polyurethane curing reaction with the prepolymerization reaction. Since the curing is performed by a reaction mechanism similar to the one-shot manufacturing method without passing through, the effect of using the prepolymer method is reduced. In the case of using an isocyanate component in which a polyol has been prepolymerized with a polyisocyanate in advance, in addition to the polyol component, diols such as ethylene glycol and butanediol, and polyols such as trimethylolpropane and sorbitol, and the like, Derivatives can also be used.

Polyurethane raw materials include conductive agents such as electrolytes, conductive materials such as carbon black, fillers such as carbon black and inorganic carbonates, antioxidants such as phenol and phenylamine, low friction agents, and charge control agents. Etc. can be added. Examples of the catalyst used for the curing reaction of the polyurethane raw material include monoamines such as triethylamine and dimethylcyclohexylamine; diamines such as tetramethylethylenediamine, tetramethylpropanediamine and tetramethylhexanediamine; pentamethyldiethylenetriamine, pentamethyldipropylenetriamine;
Triamines such as tetramethylguanidine, cyclic amines such as triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methyl Alcohol amines such as hydroxyethylpiperazine, hydroxyethylmorpholine, bis (dimethylaminoethyl) ether, ethylene glycol bis (dimethyl)
Ether amines such as aminopropyl ether, stannas octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker, dioctyltin thiocarboxylate, phenylmercurypropion And organometallic compounds such as lead octenoate. These catalysts may be used alone or in combination of two or more.

In the present invention, it is preferable to mix a silicone foam stabilizer and various surfactants with the polyurethane raw material in order to stabilize the cells of the foam material. As the silicone foam stabilizer, a dimethylpolysiloxane-polyoxyalkylene copolymer or the like is preferably used and has a molecular weight of 35.
Those comprising a dimethylpolysiloxane moiety of 0 to 15000 and a polyoxyalkylene moiety having a molecular weight of 200 to 4000 are particularly preferred. The molecular structure of the polyoxyalkylene moiety is preferably an ethylene oxide addition polymer or a co-addition polymer of ethylene oxide and propylene oxide, and it is also preferable that the molecular terminal is ethylene oxide. Examples of the surfactant include cationic surfactants, anionic surfactants, ionic surfactants such as amphoteric surfactants, and nonionic surfactants such as various polyethers and various polyesters. The compounding amount of the silicone foam stabilizer and various surfactants is preferably 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polyurethane material.
More preferably, it is 5 parts by weight. The amount of the silicone foam stabilizer and various surfactants is 100
The amount is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to parts by weight.

The polyurethane foam used in the present invention comprises:
Preferably a density of 0.2 to 0.8 g / cm ^3, more preferably 0.3-0.6 g / cm ^3. The Asker C hardness of the polyurethane foam is preferably from 20 to 65 °, more preferably from 25 to 45 °. In the present invention, as a method of foaming the polyurethane raw material in advance, conventionally used methods such as a mechanical floss method, a water foaming method, and a foaming agent floss method can be used, and the density is 0.2 to 0.8 g. From the viewpoint of obtaining a polyurethane foam having an Asker C hardness of 20 to 65 ° / cm ³ , a mechanical floss method of mechanically stirring and foaming while mixing an inert gas is preferable. Here, the inert gas used in the mechanical floss method may be an inert gas in the polyurethane reaction, and may be an inert gas in a narrow sense such as helium, argon, xenon, radon, and krypton.
Gases that do not react with the polyurethane raw material, such as nitrogen, carbon dioxide, and dry air, may be mentioned. By casting the foamed polyurethane material into a metal mold and curing it,
A polyurethane foam having a self-skin layer (thin layered film) formed in a portion in contact with the metal mold can be obtained. At that time, the metal mold can be provided with mold releasability by a method such as coating the inner surface of the metal mold with a fluororesin or the like.

The coating composition comprising an aqueous polyurethane emulsion used in the present invention is obtained by suspending polyurethane fine particles in water. The particle size of polyurethane fine particles is 0.1
~ 0.8 μm is preferable, and more preferably 0.05-0.3 μm
m, and the amount of the polyurethane fine particles used is preferably such that the proportion of non-volatile components is 3 to 70% by weight, more preferably 8 to 50% by weight. Examples of the method of suspending include a method of optimizing the molecular structure of the polyurethane to have a self-emulsifying property, a method of adding an emulsifier such as a surfactant, and the like, and a method of self-emulsification is most preferable.

The coating comprising an aqueous emulsion of polyurethane is preferably crosslinked to impart moisture resistance. Examples of the crosslinking method include a method of crosslinking with a self-emulsifying polyinesocyanate and a blocked isocyanate, a method of crosslinking with melamine, Examples include a method of crosslinking with a silane coupling agent, and the method of crosslinking with a silane coupling agent is most preferable from the viewpoint of the pot life of the raw material of the crosslinking agent in the production process. It is considered that the cross-linking method using a silane coupling agent causes a silylation reaction of the ends and side chains of the polyurethane chain by the silane coupling agent, and further forms a cross-linked structure by a reaction between the silane coupling agents. The silane coupling agent that can be used in the present invention has a structure of aminosilane, isocyanate silane, methacrylsilane, mercaptosilane, or the like, and the molecular structure of the polyurethane fine particles used in a coating composed of an aqueous emulsion of polyurethane has a hydroxyl group. When isocyanate groups remain, those having an isocyanate silane structure are preferable, and when isocyanate groups remain, those having an aminosilane structure are preferable.

It is preferable that fine particles of fluorine are added to the coating composition comprising an aqueous emulsion of polyurethane in order to reduce the friction coefficient of the coating film surface. The particle size of the fine fluorine particles is preferably 0.05 to 5 μm, more preferably
0.1 to 1 μm. The compounding amount of the fine fluorine particles is preferably 0.1 to 40% by weight, more preferably 0.5 to 20% by weight in terms of the resin (polyurethane fine particle) weight ratio. In addition, it is preferable to mix conductive fine particles in the paint composed of the aqueous emulsion of polyurethane in order to adjust the electrical characteristics of the transfer member. As the conductive fine particles, carbon black such as gas black and oil furnace black and conductive metal oxide such as conductive zinc white can be used, and carbon black is most preferable. The carbon book preferably has a specific surface area of 8 to 1500 m ² / g and a dibutyl phthalate oil absorption of 25 to 500 ml / 100 g as measured by a nitrogen gas adsorption method, and more preferably 20 to 900 m ² / g. ,
Dibutyl phthalate oil absorption is more preferably from 27 to 37.
0 ml / 100 g. The dibutyl phthalate oil absorption is a value measured according to JIS K6221. Examples of a method of applying a coating composed of an aqueous polyurethane emulsion to a transfer member composed of a polyurethane foam include methods such as spray coating, roll coating, and dip coating. The thickness of the coating film is 8-400
μm is preferable, and 10 to 250 μm is more preferable.

The transfer member of the present invention can be used in the form of a transfer roller or the like. As the structure of the transfer roller,
Examples thereof include a metal shaft such as a shaft obtained by plating nickel or zinc on a sulfur free-cutting steel and covered with a polyurethane foam. FIG. 1 is an explanatory view showing an example of an electrophotographic image forming apparatus in which a transfer member of the present invention is mounted as a transfer roller, and holds a developer supply member (toner supply roller) 3 and a latent electrostatic latent image. A developer carrier (developing roller) 2 is disposed between the image forming body 1 and the recording medium such as paper, the outer peripheral surface of which is close to the surface of the image forming body 1. Through 8,
2 shows a structure in which a transfer member (transfer roller) 5 is brought into contact. The developer (toner) is supplied to the surface of the developer carrier 2 by the developer supply member 3 by rotating the developer supply member 3, the developer carrier 2 and the image forming body 1 in the direction of the arrow. After being formed into a uniform thin layer by the agent layer forming blade 4, it adheres to the latent image on the image forming body 1,
The latent image is visualized. Then, an electric field is generated between the image forming body 1 and the transfer member (transfer roller) 5 to transfer the developer (toner) image on the image forming body 1 to the recording medium 8. Reference numeral 6 denotes a cleaning member (cleaning roller) which removes a developer remaining on the surface of the image forming body 1 after transfer. Reference numeral 7 denotes a charging member (charging roller). Specific examples of the image forming apparatus include a plain paper copying machine, a plain paper facsimile machine, a laser beam printer, a toner jet printer, and the like.

[0016]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 is a mixture of diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, and glycol-modified diphenylmethane diisocyanate,
24.6 parts by weight of an isocyanate component having an isocyanate content of 26.2% by weight, and 60 parts by weight of a polyether polyol having a weight average molecular weight of 5,000 obtained by addition polymerization of ethylene oxide and propylene oxide with glycerin as a starting material, and 60 parts by weight of a molecular weight of 1,000 40 parts by weight of polytetramethylene ether glycol, hydroxyl value of 56 mg KO
H / g of 4 parts by weight of a reactive silicone foam stabilizer, 2.5 parts by weight of a black pigment, 0.4 parts by weight of ethyl sulphate-modified aliphatic dimethylethylammonium as an electrolyte and 0.01 parts by weight of dibutyltin dilaurate as a catalyst The resulting polyol components were mixed to prepare a polyurethane raw material. The polyurethane raw material was mechanically stirred with a mixer, mixed with dry air, and foamed. This foamed polyurethane raw material,
It was cast into a metal cylindrical split mold having an inner diameter of 17.0 mm, a length of 210.0 mm, a hole at the end for penetrating the shaft, and a metal cap for supporting the shaft. . Inside the mold, a sulfur-free-cutting steel with a galvanized outer diameter of 6.0 mm and a length of 24
An adhesive is applied to a 0 mm shaft and arranged.
Next, the mold into which the foamed polyurethane material was cast was left in a hot-air oven adjusted to 90 ° C. for 4 hours to cure the foamed polyurethane material. The cured polyurethane foam was removed from the mold, polished with a grindstone so that the outer diameter became 16.5 mm, and then both ends were cut to make the total length of the foam portion 210 mm, thereby producing a polyurethane foam transfer roller. The density of the polyurethane foam was 0.50 g / cm ³ , and the Asker C hardness was 40 °. Next, this roller was preheated for 30 minutes in a hot-air oven adjusted to 100 ° C., and the specific surface area measured by a nitrogen gas adsorption method at room temperature of 23 ° C. and a relative humidity of 50% was 6%.
1 m ² / g and dibutyl phthalate oil absorption of 125
A suspension obtained by mixing a water-based polyurethane self-emulsifying paint (nonvolatile content: 40% by weight) containing carbon black of 100 ml / ml and an isocyanate silane type silane coupling agent at a weight ratio of 95: 5 was spray-coated on the roller surface. . Next, the film was dried for 1 hour in an environment at a room temperature of 23 ° C. and a relative humidity of 50%, and then dried in a hot air oven at 100 ° C. for 30 minutes to produce a transfer roller. The thickness of the coating film was 25 μm. The electrical resistance (roller resistance) of this transfer roller was 10 ^8.0 Ω at a measurement voltage of 1000 V at a room temperature of 23 ° C. and a relative humidity of 50%. In addition,
The roller resistance was measured by applying a load of 500 g to both ends of the roller, pressing the roller against a copper plate, and applying a voltage of 1000 V using a resistivity meter R8340A (manufactured by Advantest). Also, after measuring the weight of the transfer roller, the surface of the roller is dusted with a styrene acrylic resin-based toner, and then the toner is removed using a vacuum cleaner.
The remaining toner amount was measured by measuring the weight of the transfer roller again. The residual toner amount normalized by the surface area of the polyurethane foam portion was 0.74 mg / cm ² . The residual toner amount is less than half that of the transfer roller of Comparative Example 1 described later, and it can be seen that the obtained transfer roller has improved toner cleaning properties.
The transfer roller is incorporated in the image forming apparatus shown in FIG.
Left at a temperature of 23 ° C. and a relative humidity of 50% for 48 hours,
When a gray scale, solid black and white solid image was printed, good images were obtained in all cases. Next, with the power of the image forming apparatus turned on, the temperature is 23 ° C. and the relative humidity is 50%.
And for 2 years, a gray scale, black solid and white solid image were printed, and all good images were obtained.

Comparative Example 1 A transfer roller was prepared in the same manner as in Example 1 except that the roller made of a polyurethane foam was not coated with an aqueous polyurethane self-emulsifying paint. The density of the polyurethane foam is 0.50 g / cm ^3, Asker C hardness 40 °, the roller resistance at room temperature 23 ° C., at a relative humidity of 50%, was at 10 ^7.9 Omega measured voltage 1000V. The residual toner amount measured in the same manner as in Example 1 was 1.75 mg / cm ² . When a gray scale, solid black and solid white image was printed in the same manner as in Example 1, good images were obtained in all cases. Next, the image forming apparatus was left for 2 years at a temperature of 23 ° C. and a relative humidity of 50% while the power of the image forming apparatus was turned on, and a gray scale image, a solid black image, and a solid white image were printed. An image defect occurred linearly at the position where it was considered to have been. When the photoreceptor was removed from the image forming apparatus and the surface of the roller was observed, the toner was fixed at a position where the transfer roller was considered to be in pressure contact. It is presumed that the toner remaining on the surface of the transfer roller has adhered to the photoreceptor, and it is considered that this adhesion caused an image defect.

Example 2 A polyurethane foam roller was manufactured using a cylindrical metal mold having an inner diameter of 16.5 mm, and the transfer roller was manufactured in the same manner as in Example 1 including coating, except that the surface was not polished. Was prepared. This transfer roller has a self-skin layer because the surface of the polyurethane foam is not polished. The density of polyurethane foam is 0.5
0 g / cm ³ , Asker C hardness of 43 °, roller resistance of room temperature of 23 ° C. and relative humidity of 50%, measurement voltage of 100
Was 10 ^7.8 Ω at 0V. The residual toner amount measured in the same manner as in Example 1 was 0.06 mg / cm ² . The residual toner amount is significantly lower than that of the transfer roller of Comparative Example 1, and it can be seen that the obtained transfer roller has a significantly improved toner cleaning property. When a gray scale, solid black and solid white image was printed in the same manner as in Example 1, good images were obtained in all cases. Next, with the power of the image forming apparatus turned on, the temperature 23
When left at a temperature of 50 ° C. and a relative humidity of 50% for 2 years to print gray scale, black solid and white solid images, good images were obtained in all cases.

[0019]

Since the transfer member of the present invention has excellent cleaning properties, it does not contaminate an image forming body such as a photoreceptor and is used in an electrophotographic or electrostatic recording type image forming apparatus. In this case, a good image can be obtained over a long period of time.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of an electrophotographic image forming apparatus in which a transfer member of the present invention is mounted as a transfer roller.

[Explanation of symbols]

 1: image forming body 2: developer carrying member 3: developer supplying member 4: developer layer forming blade 5: transfer member 6: cleaning member 7: charging member 8: recording medium

Claims (11)

[Claims] 1. A transfer member for an image forming apparatus, wherein a member made of a polyurethane foam produced using a polyol and a polyisocyanate as main raw materials is coated with a paint made of an aqueous emulsion of polyurethane. 2. The transfer member according to claim 1, wherein the paint comprising an aqueous emulsion of polyurethane is cross-linked by a silane coupling agent. 3. The coating composition comprising an aqueous polyurethane emulsion contains fluorine fine particles.
Or the transfer member according to 2. 4. A coating composition comprising an aqueous polyurethane emulsion containing conductive particles.
The transfer member according to any one of the above. 5. The transfer member according to claim 4, wherein the conductive particles are carbon black. 6. A polyurethane foam having a density of 0.2 to 0.2.
The transfer member according to claim 1, wherein the transfer member has a weight of 8 g / cm ³ . 7. The transfer member according to claim 1, wherein the polyurethane foam has an Asker C hardness of 20 to 65 °. 8. The transfer member according to claim 1, wherein the polyurethane foam is foamed by a mechanical floss method. 9. The transfer member according to claim 1, wherein the polyurethane foam has a self-skin layer. 10. The transfer member according to claim 1, wherein the transfer member is a transfer roller.
The transfer member according to any one of claims 1 to 9, 11. An image forming apparatus comprising the transfer member according to claim 1.