JP2009109737A - Method of manufacturing roller member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a roller member for stably manufacturing a high quality roller member by suppressing appearance failure due to coating defects, thereby preventing image defects, in a drying process by a ring head. <P>SOLUTION: The method of manufacturing the roller member is for forming the surface layer of the roller member having a shaft core body, an elastic layer formed on the circumference of the shaft core body and the surface layer formed on the circumference of the elastic layer by the ring head. The method of manufacturing the roller member includes the drying process of spraying the gas to a coating surface layer and drying it, simultaneously with the application of a surface layer-forming coating material. The relative evaporation rate (r) of the main solvent of the surface layer-forming coating material and wind speed (v) in the vicinity of a rubber roller just after the coating material is applied satisfy 5≤rv≤200ä(r): the relative evaporation rate of the main solvent (butyl acetate is set to 1) and (v): the wind speed (m/min) in the vicinity of the rubber roller}. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a roller member (charging roller or the like) used in an image forming apparatus using an electrophotographic process, particularly in OA equipment such as LBP (Laser Beam Printer), a copying machine, and a facsimile machine.

  The thin film layer is formed on the surface of the shaft core body by the ring head by discharging paint uniformly from the slits opened over the entire circumference of the inner peripheral surface of the ring head, so that the ring head and the shaft core body are relatively It can be performed by moving (Patent Documents 1 and 2). However, in the case of applying a low-viscosity and easy-to-sag paint to form a thin film layer, a poor appearance due to the sagging of the paint on the shaft core is likely to occur.

  Also, in the coating method using a conventional ring head, when a surface layer is formed on a shaft core body (rubber roller) having an elastic layer, the paint is also applied simultaneously to the gripping member surface of the rubber roller that also serves as the masking of the shaft core body. . For this reason, the paint sometimes adheres to the gripping member, and an appearance defect is likely to occur due to the paint adhering to the gripping means flowing out onto the elastic layer of the rubber roller (Patent Document 3).

  When the roller member is used as a charging roller in an image forming apparatus such as an electrophotographic apparatus or a copying machine, the roller member is brought into pressure contact with the photosensitive drum, and the surface is uniformly charged with a predetermined polarity potential. Therefore, the outer diameter accuracy of the roller member, the uniformity of the surface roughness, and the uniformity of the surface layer formed on the elastic layer are important. However, if there is uneven coating of the paint as described above, the surface layer becomes non-uniform, resulting in variations in the resistance value of the roller member, and the photosensitive drum surface cannot be uniformly charged, resulting in image defects.

JP 60-95440 A JP 61-8164 A JP 2006-17154 A

  By the way, as described above, the ring head discharges paint from the ring head to form a surface layer on the peripheral surface of the elastic layer, and also discharges gas such as air from the ring head to form the elastic layer. It is also used to dry the coated surface layer formed on the peripheral surface of the film. The drying process of the coated surface layer is a process that greatly affects the uniformity of the surface layer.

  Accordingly, an object of the present invention is to provide a roller member manufacturing method that stably prevents high-quality roller members by preventing image defects by suppressing appearance defects due to coating defects in a coating process and a drying process using a ring head. Is to provide.

The method for producing a roller member according to the present invention includes:
In the roller member manufacturing method, the surface layer of the roller member having the shaft core body, the elastic layer formed on the outer periphery thereof, and the surface layer formed on the outer periphery of the elastic layer is formed by a ring head.
A coating / drying step in which a gas is blown to the coating surface layer and air-dried at the same time as the coating for forming the surface layer is applied;
The relative evaporation rate r of the main solvent of the coating material for forming the surface layer, and the wind velocity v near the rubber roller immediately after the coating material is applied,
5 ≦ rv ≦ 200
r: Relative evaporation rate of main solvent (butyl acetate is 1)
v: Wind speed in the vicinity of the rubber roller (m / min)
This is achieved by satisfying

  Further, the drying step is a step of drying the coating surface layer by discharging a gas from a discharge port that is disposed on the outer periphery of the rubber roller and opened over the entire inner peripheral surface of the ring head. To do.

  Further, the relative evaporation rate r of the main solvent is controlled by a temperature adjusting means provided in the supply path by measuring the temperature of the solvent in the supply path of the surface layer forming paint. To do.

  According to the present invention, in a coating process and a drying process using a ring head, an image defect is prevented by suppressing an appearance defect due to a coating defect, and a roller member manufacturing method for stably manufacturing a high-quality roller member is provided. be able to.

  The roller member manufactured by the roller member manufacturing method according to the present invention has the structure shown in FIG. In FIG. 1, a roller member 1 is composed of a shaft core 1a, an elastic layer 1b, and a surface layer 1c. An elastic layer 1b is provided on the outer periphery of the shaft core 1a, and a surface layer 1c is provided on the outer periphery of the elastic layer 1b.

  Hereinafter, the method for manufacturing a roller member according to the present invention will be described in more detail with an example in which after forming a rubber roller, a coating surface layer is formed on an elastic layer by a coating process and a drying process using the ring head of the present invention and dried. explain.

[Production of rubber roller]
First, as a method of manufacturing a rubber roller by forming an elastic layer on a shaft core body, two cylindrical pieces concentrically holding a shaft core body are assembled in a cylindrical mold, and the elastic layer material is injected and heated. There is injection molding in which a material is cured to form a rubber roller. Also, after extruding the elastic layer material into a tube shape, the shaft core body is covered with the tubular elastic layer material, or the shaft core body and the elastic layer material are integrally extruded to form an elastic roller, transfer molding, There is press molding. However, it is not particularly limited. In view of shortening the manufacturing time, extrusion molding in which a rubber roller is formed by extruding the elastic layer material integrally with the shaft core body is preferable.

  The extrusion molding can be performed by an extruder equipped with a cross head, and a shaft core body fed by a shaft core body feed roller is inserted from behind the cross head, and a cylindrical elastic layer material is formed simultaneously with the shaft core body. Are extruded together. Thereafter, the end portion is cut and removed to obtain a rubber roller.

  As for the method of heating the rubber roller, any method such as a hot air oven, a vulcanizing can, a heating plate, heating by far / near infrared rays, induction heating, etc. may be used, and further, it is pushed while rotating on a heated cylindrical or planar member. A hitting method may be used. In some cases, dry grinding using a rotating grindstone may be performed to obtain a desired roller shape and roller surface roughness after heating.

  The material used as the shaft core of the rubber roller is preferably a stainless steel rod, a phosphor bronze rod, an aluminum rod, or a heat-resistant resin rod containing a steel material such as a nickel-plated SUM material.

  The elastic layer provided on the shaft core is a conductive elastic layer. Examples of rubber materials constituting such an elastic layer include natural rubber, butadiene rubber, hydrin rubber, styrene-butadiene rubber, nitrile rubber, ethylene-propylene rubber, butyl rubber, silicone rubber, urethane rubber, fluorine rubber, chlorine rubber, heat A plastic elastomer etc. are mentioned.

  Examples of the conductive agent dispersed in the elastic layer include carbons such as carbon black and conductive carbon, metal powder, conductive fiber, semiconductive metal oxide powder such as tin oxide, and a mixture thereof. Is mentioned.

[Method for forming surface layer]
Next, a method of applying the ring head to the rubber roller according to the present invention will be described in detail.

  In FIG. 2, 3 is a ring head for application, and 1d is a rubber roller in which an elastic layer 1b is formed on the peripheral surface of the shaft core 1a. Reference numeral 8 denotes a coated surface layer formed on the peripheral surface of the elastic layer 1b. Reference numeral 2 denotes a rubber roller conveying unit that holds the rubber roller 1d and moves the rubber roller 1d with respect to the coating ring head 3.

  The rubber roller 1d is disposed so as to be concentric with the ring head 3 for application. Further, the rubber roller 1d is fixed to the holding member 2 of the rubber roller 1d and held in a vertical state. Further, the rubber roller 1d and the application slit 4 are arranged at a predetermined interval.

  First, a coating material is supplied to the liquid supply port 7 from a liquid supply means (not shown) outside the coating ring head 3 (not shown).

  The supplied paint is almost filled over the entire circumference of the liquid distribution chamber 6. Thereafter, the fluid flows toward the coating slit 4, but by passing through the liquid constricting part 5, the flow velocity is increased, and the coating material in the circumferential direction is made more uniform. And it discharges to the surface of the elastic layer 1b from the slit 4 for application | coating.

  The discharge speed of the paint onto the surface of the rubber roller 1d is preferably 0.023 mL / s.

  Further, the discharge amount of the rubber roller 1d onto the surface of the gripping member 2 and the discharge amount onto the surface of the rubber roller 1d may be changed.

  For example, the discharge amount of the rubber roller 1d onto the surface of the elastic layer 1b is calculated from a desired coating film thickness and the like, and is applied onto the surface of the holding member 2 of the rubber roller 1d with a smaller discharge amount. Thereby, it is possible to effectively suppress the paint from dripping from the holding member 2 of the rubber roller 1d onto the surface of the rubber roller 1d.

  Further, the coating surface layer 8 applied to the surface of the elastic layer 1b was discharged from the drying slit 10 of the drying ring head 9 disposed at the top of the coating ring head 3 simultaneously with the application of the paint. Gas is blown to dry the coated surface layer 8.

  FIG. 2 shows a ring head 9 for drying. Reference numeral 10 denotes a gas discharge port (drying slit) opened on the entire circumference of the inner peripheral surface of the ring head, and 11 denotes a gas supply port. In the present embodiment, the drying ring head 9 is disposed on the coating ring head 3 with the spacer 12 interposed therebetween, but the present invention is not limited to this.

At this time, in the present invention, the relative evaporation speed r of the main solvent of the surface layer forming paint and the wind speed v near the rubber roller immediately after the paint is applied are:
5 ≦ rv ≦ 200
r: Relative evaporation rate of main solvent (butyl acetate is 1)
v: Wind speed in the vicinity of the rubber roller (m / min)
It is.

  Immediately after coating the elastic layer with the coating ring head, the solvent evaporates from the surface of the coated coating. At this time, the faster the solvent evaporates, the faster the increase in viscosity with the increase in the concentration of the applied paint, and the greater the effect of suppressing sagging. The evaporation of the solvent is affected by the wind speed near the surface. As the evaporation proceeds, the concentration of the solvent vapor increases near the surface, and the vapor pressure of the solvent approaches the saturated vapor pressure. Evaporation proceeds faster as the difference between the solvent vapor pressure and the saturated vapor pressure increases, so that evaporation near the liquid surface of the solvent is diffused to prevent the increase in the solvent vapor pressure, thereby promoting evaporation.

  As a result of intensive studies, if the rv value is within the above range, the coating applied on the elastic layer of the rubber roller is appropriately dried. As a result, the surface layer can be formed without causing appearance defects due to coating defects caused by dripping of the paint on the elastic layer or the paint adhering to the gripping member flowing out onto the elastic layer of the rubber roller. A high-quality roller member can be obtained.

  When the rv value is less than 5, the paint is dried slowly and the sag occurs. On the other hand, when the rv value exceeds 200, the coating is dried too quickly, resulting in coating defects such as coating stripes.

  The relative evaporation rate r of the main solvent of the paint can be controlled by controlling the temperature of the paint. That is, when using a solvent that is slow to evaporate and satisfies the solubility and coating properties of the surface layer forming material, the relative evaporation rate can be increased by raising the solvent temperature. Thereby, since the rv value falls within the above range, the roller member can be obtained without causing dripping.

  The means for managing the solvent temperature is not particularly limited. For example, a temperature sensor is arranged in the paint supply path, and a temperature adjusting means for adjusting the temperature by comparing the measured temperature with the set value is arranged. Is achieved.

The evaporation rate of the main solvent, butyl acetate, is measured by weighing the solvent into a container with a known area, evaporating it for a predetermined time, and then measuring again to determine the evaporation amount. The reference evaporation rate of butyl acetate is 0.8 mg / (cm ² · min).

  The wind velocity v near the rubber roller at the moment of forming the coating surface layer can be controlled by the supply speed of the gas supplied to the ring head. The wind velocity v near the rubber roller is measured by an anemometer. Here, the vicinity of the rubber roller at the moment of forming the coating layer refers to a range of 20 mm from the surface of the rubber roller.

  The width of the discharge port opened over the entire circumference of the inner peripheral surface of the coating ring head is preferably 0.01 mm or more and 1.0 mm or less, and is selected and determined by the liquid viscosity of the coating material and the material added to the coating material.

  As the material for forming the surface layer, silicone-based, fluorine-based, urethane-based, acrylic-based, urethane-modified acrylic-based, and silicone-modified urethane-based materials are used. In particular, a material containing polysiloxane having a fluorinated alkyl group and an oxyalkylene group is preferable.

  As the solvent that can be used in the present invention, a solvent that can satisfy the range of the rv value and has good solubility in the surface layer forming material is used. Examples thereof include alcohols such as ethanol and 2-butanol, ethyl acetate, methyl ethyl ketone, and the like, or a mixture thereof.

  The viscosity of the paint is preferably a low-viscosity paint in order to form a surface layer having a thickness of 10 nm or more and less than 1000 nm, and a B-type viscometer value of 0.5 to 2.0 mPa · s is preferred.

  The concentration of the coating material in the present invention is preferably such that the content of the main solvent is 50 to 99% by mass from the viewpoint of forming a thin film layer of 10 nm or more and less than 1000 nm and the solubility of the surface layer forming material.

  The relative moving speed of the rubber roller and the ring head is preferably 1 to 200 mm / s. Within the said range, the uniformity of the application | coating of the circumferential direction to the rubber roller surface and the uniformity of drying are high.

  As the drying gas, a chemically inert and stable gas is suitable. For example, air, nitrogen, helium, argon, etc. are mentioned.

  The gas temperature and humidity may be set arbitrarily.

  Furthermore, it is preferable to insert an air filter and a mist separator between the supply side pressure line and the precision regulator in order to prevent drainage and dust on the supply side pressure line.

  Further, regarding the surface layer of the roller member of the present invention, the layer thickness is preferably a thin film in terms of electrical characteristics or strength, and is 10 nm or more and less than 1000 nm. Here, for example, when the thickness of the surface layer is less than 10 nm, there is a possibility that the electrical characteristics and surface free energy characteristics as the surface layer cannot be satisfied. Further, when the thickness of the surface layer is 1000 nm or more, if the hardness of the surface layer is large, the surface layer may crack without being able to follow the elastic layer.

  Next, a method for curing the coated surface layer formed by discharging paint on the rubber roller surface will be described. The coated surface layer may be heat cured. In this case, any method such as a hot stove, a hot platen, heating by far / near infrared rays, induction heating or the like may be used, or these heating methods may be used in combination. Moreover, you may make it harden | cure by irradiating an active energy ray, and hardening in a short time is attained in this case. The active energy ray may be an ultraviolet ray or an electron beam. In addition, when the coated surface layer is irradiated with active energy rays, the elastic layer is simultaneously modified and cured. In particular, a rubber having an elastic layer having a double bond is preferable because the effect of modification and curing by irradiation with active energy rays is large.

  The roller member obtained by the roller member manufacturing method of the present invention is used as an electrophotographic member of an image forming apparatus such as an LBP (Laser Beam Printer), a copying machine, or a facsimile. Here, FIG. 3 shows a usage pattern when used as a charging roller. The image forming apparatus is a rotating drum type / transfer type electrophotographic apparatus, and 13 is an electrophotographic photosensitive member (photosensitive drum) as an image carrier, which rotates clockwise at a predetermined peripheral speed (process speed). Driven. The photosensitive drum 13 is uniformly charged to a predetermined polarity and potential (-600 V in this embodiment) by a charging roller 14 to which a charging bias is applied from a power source E1 as a charging means during the rotation process. Next, the exposure system 15 receives negative image exposure (analog exposure of the original image, digital scanning exposure) corresponding to the target image information, and an electrostatic latent image of the target image information is formed on the peripheral surface. Thereafter, the electrostatic latent image is developed as a toner image by a toner developing roller 16 of a reversal development method using minus toner. Then, the toner image is fed at a predetermined timing from a sheet feeding means (not shown) to a transfer portion between the photosensitive drum 13 and a transfer roller 17 as a transfer means. A transfer bias of about +2 to 3 KV is applied to the transfer roller 17 from the power source E2, and the toner images that have been reversely developed on the surface of the photosensitive drum 13 are sequentially transferred onto the transfer material. The transfer material that has received the transfer of the toner image is separated from the surface of the photosensitive drum 13 and introduced into fixing means (not shown) to undergo image fixing processing. The surface of the photosensitive drum 13 after the transfer of the toner image is subjected to a removal process of adhering contaminants such as transfer residual toner by the cleaning unit 18 to be cleaned and repeatedly used for image formation.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to these.

Defects on the appearance of the roller member surface layer formed in each example and comparative example (coating irregularity, liquid dripping, etc.) were visually evaluated as follows.
Evaluation A: No defects such as uneven coating Evaluation B: Almost no defects such as uneven coating Evaluation C: There are defects such as uneven coating.

In addition, when the manufactured roller member is used as a charging roller, image defects are caused by incorporating the roller member into an electrophotographic cartridge and outputting a halftone image in an environment of 23 ° C. and a humidity of 60%. Evaluation was performed as follows.
Evaluation A: No defects such as image unevenness. Evaluation B: Almost no defects such as image unevenness and practical problems. Evaluation C: Defects such as image unevenness (practical defects).

(Example 1)
<Ring head>
As the ring head used in this example, the ring head shown in FIG. 2 was used.

(Ring head for application)
The ring head 3 for application has an outer diameter of 42 mm and an inner diameter of 8.7 mm, and the discharge port (application slit) 4 opened to the entire circumference has a width of 0.1 mm.

(Ring head for drying)
The drying ring head 9 has an outer diameter of 42 mm and an inner diameter of 10 mm, and a gas discharge port (drying slit) 10 opened to the entire circumference has a width of 0.35 mm.

(Spacer)
A spacer 12 having a height of 10 mm was used.

<Production of rubber roller>
The following raw materials were kneaded with a pressure kneader for 15 minutes.
・ NBR (acrylonitrile-butadiene copolymer rubber) 100 parts by mass (trade name: “Nipol DN219”, manufactured by Nippon Zeon Co., Ltd.)
-14 parts by mass of carbon black 1 (trade name: “Asahi HS-500”, manufactured by Asahi Carbon Co., Ltd.)
Carbon black 2 4 parts by mass (Product name: “Ketjen Black EC600JD”, manufactured by Lion Corporation)
・ Zinc stearate 1 part by mass ・ Zinc oxide 5 parts by mass ・ Calcium carbonate 30 parts by mass (trade name: “NANOX # 30”, manufactured by Maruo Calcium Co., Ltd.)

  Further, 1 part by mass of vulcanization accelerator (DM: di-2-benzothiazolyl disulfide), 3 parts by mass of vulcanization accelerator (TBzTD: tetrabenzylthiuram disulfide) and 1.2 parts by mass of vulcanization agent (sulfur) were added. In addition, an unvulcanized rubber composition was prepared by kneading with an open roll for 15 minutes. Next, a shaft core of a stainless steel rod having an outer diameter of 6 mm and a length of 252 mm was prepared. Here, the shaft core and the unvulcanized rubber composition were integrally extruded using a crosshead extruder to form a rubber roller. Thereafter, heat vulcanization was performed at 160 ° C. for 1 hour, and further, dry polishing using a rotating grindstone and cutting / removal processing of an end portion were performed to obtain a rubber roller having a thickness of 1.25 mm and a length of 232 mm (rubber roller outer diameter φ8. 5 mm).

<Formation of surface layer>
The following raw materials were prepared.
-Glycidoxypropyltriethoxysilane (GPTES): 12.47 g (0.045 mol)
Phenyltriethoxysilane (PhTES): 43.08 g (0.179 mol)
-Hexyltrimethoxysilane (HeTMS): 13.21 g (0.064 mol)
Tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane (FTS, carbon number of perfluoroalkyl group 6): 16.32 g (0.032 mol) (10 mol with respect to the total amount of hydrolyzable silane compound) % Equivalent)
・ Water: 25.93g
・ Ethanol: 74.16g

  After mixing the raw materials, the mixture was stirred at room temperature and then heated to reflux for 24 hours to hydrolyze and condense the hydrolyzable silane compound to obtain a hydrolyzable condensate. By adding this hydrolyzable condensate to a mixed solvent of 2-butanol / ethanol (2-butanol / ethanol = 10/65 (mass ratio)), a hydrolyzable condensate-containing alcohol solution having a solid content of 7% by mass Was prepared. 28 g of the hydrolyzable condensate-containing alcohol solution having a solid content of 7% by mass and 72 g of ethanol as the main solvent were mixed and stirred to prepare an ethanol solution having a solid content of 2% by mass. For 100 g of this hydrolyzable condensate-containing ethanol solution, 0.4 g of an aromatic sulfonium salt (trade name: “Adekaoptomer SP-150”, manufactured by Asahi Denka Kogyo Co., Ltd.) as a photocationic polymerization initiator. A coating for the surface layer was prepared by adding.

  Place the rubber roller prepared earlier so that it is concentric with the ring head, supply the paint prepared earlier to the liquid supply port of the ring head, and form a coating surface layer on the peripheral surface of the elastic layer of the rubber roller did. At the same time, air was supplied from a gas supply port to dry the coated surface layer.

  The ring head was vertically moved at a constant speed of 85 mm / s with respect to the surface of the rubber roller, and at the same time, the coating material was applied at a discharge speed of 0.07 mL and 0.023 mL / s.

  At that time, the liquid temperature of the paint was 20.1 ° C., and the relative evaporation rate of ethanol as the main solvent was 1.5. The wind speed near the rubber roller was 52 m / s. Therefore, rv = 80.1.

Thereafter, ultraviolet irradiation with a low-pressure mercury lamp (manufactured by Harrison Toshiba Lighting) was performed for 5 minutes. Regarding the low-pressure mercury lamp, the ultraviolet ray mainly represented by a wavelength of 254 nm was used, and the ultraviolet ray integrated light quantity at this time was about 10,000 mJ / cm ² (the ultraviolet ray intensity was 35 mW / cm ² ).

  As a result of visual evaluation of the roller member surface of this example, no appearance defect due to coating unevenness was found on the roller member surface (evaluation: A).

  Further, this roller member is incorporated as a charging roller in the electrophotographic image forming apparatus shown in FIG. 5, and is pressed into contact with both ends of the photosensitive drum loaded with a load of 500 g, in an environment of 23.5 ° C./60%. Initial image evaluation with halftone images was performed. In this evaluation, a good image was obtained with the roller member of this example (evaluation: A). The results are shown in Table 1.

(Example 2)
A roller member was produced in the same manner as in Example 1 except that the wind speed in the vicinity of the rubber roller was 8 m / s. At that time, the liquid temperature was 19.9 ° C., and the relative evaporation rate of ethanol as the main solvent was 1.5. Therefore, rv = 12.3.

  As a result of visual evaluation of the roller member surface of this example, no appearance defect due to coating unevenness was found on the roller member surface (evaluation: A).

  Further, this roller member is incorporated as a charging roller in the electrophotographic image forming apparatus shown in FIG. 5, and is pressed into contact with both ends of the photosensitive drum loaded with a load of 500 g, in an environment of 23.5 ° C./60%. Initial image evaluation with halftone images was performed. In this evaluation, the roller member of this example was able to obtain a good image (evaluation: A). The results are shown in Table 1.

(Example 3)
A roller member was produced in the same manner as in Example 1 except that methyl ethyl ketone was used in place of ethanol as the main solvent for the paint. At that time, the liquid temperature was 20.0 ° C., and the relative evaporation rate of methyl ethyl ketone as the main solvent was 3.7. Therefore, rv = 192.4.

  As a result of visual evaluation of the roller member surface of this example, extremely thin stripe-like coating unevenness was observed on the roller member surface (evaluation: B).

  Further, this roller member is incorporated as a charging roller in the electrophotographic image forming apparatus shown in FIG. 5, and is pressed into contact with both ends of the photosensitive drum loaded with a load of 500 g, in an environment of 23.5 ° C./60%. Initial image evaluation with halftone images was performed. In this evaluation, the roller member of this example was able to obtain a good image (evaluation: A). The results are shown in Table 1.

Example 4
A roller member was produced in the same manner as in Example 1 except that 2-butanol was used in place of ethanol as the main solvent of the paint, and the wind speed in the vicinity of the rubber roller was set to 8 m / s. At that time, the liquid temperature was 20.2 ° C., and the relative evaporation rate of 2-butanol as the main solvent was 0.6. Therefore, rv = 5.2.

  As a result of visual evaluation of the surface of the roller member of this example, very slight liquid dripping was observed on the surface of the roller member (evaluation: B).

  Further, this roller member is incorporated as a charging roller in the electrophotographic image forming apparatus shown in FIG. 5, and is pressed into contact with both ends of the photosensitive drum loaded with a load of 500 g, in an environment of 23.5 ° C./60%. Initial image evaluation with halftone images was performed. In this evaluation, the roller member of this example showed slight image defects due to dripping (evaluation: B). The results are shown in Table 1.

(Comparative Example 1)
A roller member was produced in the same manner as in Example 1 except that ethyl acetate was used in place of ethanol as the main solvent for the paint. At that time, the liquid temperature was 20.2 ° C., and the relative evaporation rate of ethyl acetate as the main solvent was 4.2. Therefore, rv = 218.4.

  As a result of visual evaluation of the roller member surface of this example, an appearance defect due to dripping was observed on the roller member surface (evaluation: C).

  Further, this roller member is incorporated as a charging roller in the electrophotographic image forming apparatus shown in FIG. 5, and is pressed into contact with both ends of the photosensitive drum loaded with a load of 500 g, in an environment of 23.5 ° C./60%. Initial image evaluation with halftone images was performed. In this evaluation, the roller member of this comparative example showed an image defect due to an appearance defect (evaluation: C). The results are shown in Table 1.

(Comparative Example 2)
A roller member was produced in the same manner as in Example 1 except that 2-butanol was used in place of ethanol as the main solvent of the paint, and the wind speed in the vicinity of the rubber roller was changed to 5 m / s. At that time, the liquid temperature was 20.2 ° C., and the relative evaporation rate of 2-butanol as the main solvent was 0.6. Therefore, rv = 3.2.

  As a result of visual evaluation of the roller member surface of this example, an appearance defect due to dripping was observed on the roller member surface (evaluation: C).

  Further, this roller member is incorporated as a charging roller in the electrophotographic image forming apparatus shown in FIG. 5, and is pressed into contact with both ends of the photosensitive drum loaded with a load of 500 g, in an environment of 23.5 ° C./60%. Initial image evaluation with halftone images was performed. In this evaluation, the roller member of this comparative example showed an image defect due to an appearance defect (evaluation: C). The results are shown in Table 1.

Roller member Schematic diagram of application and drying with a ring head Configuration diagram showing outline of image forming apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roller member 1a Shaft core body 1b Elastic layer 1c Surface layer 1d Rubber roller 2 Rubber roller holding member (Rubber roller conveying means)
3 Ring head for application 4 Discharge port (slit for application) opened all around
DESCRIPTION OF SYMBOLS 5 Liquid throttling part 6 Liquid distribution chamber 7 Liquid supply port 8 Coating surface layer 9 Drying ring head 10 Gas discharge port (drying slit) opened all around
11 Gas supply port 12 Spacer 13 Electrophotographic photosensitive member (photosensitive drum)
14 Charging roller (charging means)
15 Exposure system 16 Developing roller (developing means)
17 Transfer roller (transfer means)
18 Cleaning means E1, E2, E3 Power supply for bias application

Claims (4)

In a roller member manufacturing method in which the surface layer of a roller member having a shaft core, an elastic layer formed on the outer periphery thereof, and a surface layer formed on the outer periphery of the elastic layer is formed by a ring head.
At the same time as applying the coating for forming the surface layer, it has a drying process in which a gas is blown and dried on the coating surface layer,
The relative evaporation rate r of the main solvent of the coating material for forming the surface layer, and the wind velocity v near the rubber roller immediately after the coating material is applied,
5 ≦ rv ≦ 200
r: Relative evaporation rate of main solvent (butyl acetate is 1)
v: Wind speed in the vicinity of the rubber roller (m / min)
The manufacturing method of the roller member characterized by satisfy | filling.   The drying step is a step of drying the coated surface layer by discharging gas from a discharge port that is disposed on the outer periphery of the rubber roller and opened over the entire inner peripheral surface of the ring head. Item 2. A method for producing a roller member according to Item 1.   The relative evaporation rate r of the main solvent is controlled by temperature adjusting means provided in the supply path by measuring the temperature of the solvent in the supply path of the surface layer forming paint. Item 3. The method for producing a roller member according to Item 1 or 2.   A roller member having a surface layer of 10 nm or more and less than 1000 nm manufactured by the method for manufacturing a roller member according to claim 1.

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