JP4484614B2 - Method for producing elastic roller - Google Patents

Description

  The present invention relates to a method for manufacturing an elastic roller such as a charging roller used in an electrostatic latent image process in a copying machine, a printer, or the like.

  Conventionally, in an electrophotographic apparatus such as a copying machine or a printer, first, the surface of the photosensitive member is uniformly charged, and an image is projected onto the photosensitive member from the optical system to erase the charged portion. An electrostatic latent image is obtained by an electrostatic latent image process for forming a latent image, and then the electrostatic latent image is visualized as a toner image by adhesion of toner, and by transferring the toner image to a recording medium such as paper, The method of printing is taken.

  In order to charge the surface of the photosensitive member, a contact charging method for charging the surface of the photosensitive member by applying an elastic roller to the photosensitive member and applying a voltage to the elastic roller while rotating them is widely implemented. ing. The elastic roller used in this contact charging method is called a charging roller. For example, a material such as rubber or urethane foam is injected into a mold or extruded from an extruder to form an elastic layer around the shaft. A resistance adjustment layer is formed on the outer side of the elastic layer in the radial direction by adding a conductive agent to a resin such as urethane, acrylic urethane, acrylic ester, nylon, or a synthetic rubber such as NBR, and further adjusting the resistance. In addition, a resin layer in which a resin such as acrylic, urethane, or nylon is dissolved in an organic solvent or water is applied by a dipping method to form a skin layer (see, for example, Patent Document 1).

In such a charging roller, when the resistance adjustment layer or the skin layer is thick, it is necessary to repeatedly apply these layers by coating, which reduces productivity. Has become a problem, and countermeasures have been sought.
JP 2003-131474 A

  The present invention has been made in view of such problems, and relates to the manufacture of an elastic roller typified by a charging roller. In forming a layer positioned outside the elastic layer, the thick layer is reduced in cost. It is an object of the present invention to provide a production method that can be efficiently formed.

(1) is a method of manufacturing an elastic roller in which one or more layers are arranged outside an elastic layer provided around the shaft.
The elastic layer is formed by a method that does not depend on dip coating, and at least one of the layers disposed outside the elastic layer is formed by coagulating rubber latex ,
The step of coagulating rubber latex to form the layer includes a step of forming a coagulant layer made of a coagulant having a predetermined thickness, and a step of dip-coating the rubber latex around the coagulant layer to coagulate the rubber latex. And in the step of forming the coagulant layer, the thickness of the coagulant is changed to adjust the thickness of the layer made of rubber latex .

( 2 ) is a method for producing an elastic roller according to ( 1 ), in which the layer of rubber latex is finished in a cross-sectional crown shape by increasing the thickness of the central part of the coagulant in the shaft length direction from both ends. is there.

( 3 ) removes deposits made of salt and unreacted rubber latex from the elastic roller after the step of coagulating rubber latex in ( 1 ) or ( 2 ) An elastic roller that sets a longitudinal end position of the coagulant layer before solidifying the rubber latex so that the surface of the end of the shaft having a predetermined length is exposed after the cleaning step is provided and the deposit is removed. It is a manufacturing method.

( 4 ) In ( 3 ), the elastic roller is immersed in a dip tank containing a coagulant to form the coagulant layer, and the predetermined coagulant adhering to the elastic roller tip including the shaft tip It is a manufacturing method of the elastic roller which sets the length direction end part position of the above-mentioned coagulant layer by wiping off the length part.

( 5 ) In ( 3 ), the elastic roller is immersed in a dip tank containing a coagulant to form the coagulant layer, and the predetermined coagulant adhering to the elastic roller tip including the shaft tip This is a method for manufacturing an elastic roller in which the lengthwise end position of the coagulant layer is set by washing and removing the length portion.

( 6 ) In ( 3 ), the elastic roller is immersed in a dip tank that contains a coagulant to form the coagulant layer, and prior to this immersion, the elastic roller tip including the shaft tip is predetermined. This is a method for manufacturing an elastic roller in which the lengthwise end position of the coagulant layer is set by masking the length portion with a masking tape and removing the masking tape after immersion.

( 7 ), in ( 3 ), by forming a coagulant layer on the elastic roller surface by coating the coagulant coating liquid with a roll coater, and adjusting the coating area in the roll coater coating, It is the manufacturing method of the elastic roller which sets the length direction edge part position of a coagulant layer.

  According to the invention of (1), in forming the layer located outside the elastic layer, at least one layer is formed using a latex coagulation method capable of forming a thick rubber layer by a single operation. Since the thick film is formed by repeating the dip coating many times, it is possible to reduce the number of times of immersion in the dip tank and reduce the equipment cost and improve the productivity.

According to the invention of ( 1 ), the thickness of the layer of the rubber latex formed when the coagulant dip-coated around the shaft reacts with the rubber latex emulsified in water to coagulate the rubber latex. Since the thickness of the rubber latex is adjusted by changing the thickness of the coagulant that determines the thickness, the thickness of the layer made of the rubber latex can be easily adjusted with high accuracy. As a method of adjusting the thickness of the rubber latex, there is also a method in which a concentration distribution is added to the rubber latex solution and the concentration distribution is controlled, or the pH distribution of the rubber latex solution is provided to control the pH distribution. However, the method of changing the thickness of the coagulant can control the thickness of the layer with high accuracy as compared with these methods.

According to the invention of ( 2 ), since the cross-sectional shape of the layer made of rubber latex is determined by distributing the thickness of the coagulant in the shaft length direction, this layer can be accurately finished in a crown shape. .

According to the invention of ( 3 ), after the step of coagulating the rubber latex, there is provided a washing step for removing the salt produced in this step and the deposit made of unreacted rubber latex from the elastic roller, Before the rubber latex is solidified so that the surface of the end of the shaft having a predetermined length is exposed after the deposit is removed, the end position in the longitudinal direction of the coagulant layer is set. Compared with the method of removing the solidified rubber latex at the tip after solidifying to the end, the shaft can be exposed very easily.

According to the invention of ( 4 ), the elastic roller is immersed in a dip tank containing the coagulant to form the coagulant layer, and a predetermined length of the coagulant adhered to the elastic roller tip including the shaft tip. Since the thickness portion is wiped off, the position of the end portion in the length direction of the coagulant layer can be easily set.

According to the invention of ( 5 ), the elastic roller is immersed in a dip tank containing the coagulant to form the coagulant layer, and the predetermined length of the coagulant adhered to the elastic roller tip including the shaft tip. Since this portion is removed by washing, the position of the end portion in the longitudinal direction of the coagulant layer can also be set easily.

According to the invention of ( 6 ), the elastic roller is immersed in a dip tank containing a coagulant to form the coagulant layer, and prior to this immersion, the predetermined length of the elastic roller tip including the shaft tip The position of the end portion in the length direction of the coagulant layer can be set by masking the portion with a masking tape and removing the masking tape after immersion.

  The reason for using a masking tape with almost no thickness instead of a masking cap as a tool for masking the shaft is that if each end of the shaft is masked with a thick masking cap, the masking cap A wide range of the elastic layer adjacent to the axial center side of the film becomes thicker than the axial center side thickness. By using a masking tape that has almost no thickness instead of the masking cap, it is uniform over the entire axial length. This is because an elastic layer with a sufficient thickness can be formed.

According to the invention of ( 7 ), since the coagulant layer is formed on the surface of the elastic roller by coating the coagulant coating liquid with a roll coater, this is also precisely the length direction of the coagulant layer. The end position can be set.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the elastic roller is an example of a charging roller used for charging the surface of the photosensitive member, FIG. 1 is a cross-sectional view of the charging roller, and FIG. 2 is a process of manufacturing the charging roller. It is process drawing which shows a flow. The charging roller 10 includes a shaft 1, an elastic layer 2 disposed around the shaft 1, a skin layer 4 that forms a roller peripheral surface, and a resistance adjustment layer provided between the elastic layer 2 and the skin layer 4. It consists of three. Here, the shaft 1 is a portion that is pivotally supported by an electrophotographic apparatus such as a printer, and is made of metal or plastic.

The elastic body constituting the elastic layer 2 may be an elastic body capable of obtaining a good contact state with a charged body such as a photoreceptor, and may be a known rubber or resin, or a foam thereof (hereinafter referred to as “ Form)). Specifically, silicone rubber, butadiene rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, polynorbornene rubber, styrene-butadiene-styrene rubber, epichlorohydrin rubber, natural rubber, etc. are used as the base rubber. A rubber composition or polyurethane is exemplified. In the case of foam, the expansion ratio of rubber or polyurethane foam is not particularly limited, but is preferably 1.2 to 50 times, particularly preferably about 1.5 to 10 times, and the foam density is 0.1 to 0.00. A value of about 8 g / cm ³ is appropriate. When the foam density is smaller than 0.1 g / cm ³ , the compression set becomes large, and when it is larger than 0.8 g / cm ³ , the shape hardly changes even with the same external force. The foam density is more preferably 0.4 to 0.6 g / cm ³ .

By adding a conductive agent to the elastic layer 2, conductivity can be imparted or adjusted to a predetermined resistance value. The conductive agent is not particularly limited, but lauryltrimethylammonium, stearylmethylammonium, octadodecyltrimethylammonium, hexadecyltrimethylammonium, modified fatty acid / dimethylethylammonium perchlorate, chlorate, borofluoride , Cationic surfactants such as quaternary ammonium salts such as halogenated benzyl salts such as sulfates, etosulphate salts, benzyl bromide salts, benzyl chloride salts, aliphatic sulfonates, higher alcohol sulfates, Anionic surfactants such as higher alcohol ethylene oxide addition sulfate, higher alcohol phosphate, higher alcohol ethylene oxide addition phosphate, higher alcohol ethylene oxide, polyethylene glycol fatty acid ester Antistatic agents such as polyhydric nonionic antistatic agents such as alcohol fatty acid _{ester, NaClO 4, LiAsF 6, LiBF} 4, NaSCN, KSCN, such as NaCl Li ^+, Na ^+, periodic table first K +, etc. Electrolytes such as group metal salts or NH ₄ ⁺ salts, conductive carbons such as ketjen black and acetylene black, rubber carbons such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT, Oxidized carbon for color (ink), pyrolytic carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, germanium and other metals and metal oxides, polyaniline , Conductive polymers such as polypyrrole and polyacetylene. In this case, the blending amount of these conductive agents is appropriately selected according to the type of the composition, and the volume resistivity of the elastic layer is usually 10 ⁰ to 10 ⁸ Ω · cm, preferably 10 ² to 10 ⁶ Ω · cm. It is adjusted to become.

  In addition to the conductive agent, a thickening agent is added to the elastic layer 2 to thicken the coating film formed by one immersion. Further, if necessary, an appropriate amount of known additives such as an antifoaming agent, a leveling agent, a dispersant, a thixotropy imparting agent, a wetting agent, an antiblocking agent, a crosslinking agent, and a film forming aid can be blended.

  The thickness of the elastic layer 2 is appropriately set according to the form and size of the roller, the layer configuration and the like, and is not particularly limited, but is usually 0.3 to 10 mm, particularly 0.2 to It is preferable to be about 3 mm.

The resistance adjusting layer 3 disposed on the outer side in the radial direction of the elastic layer 2 is a resin composition obtained by adding a conductive agent to a low resistance resin base material having a volume resistivity of 1 × 10 ⁴ to 1 × 10 ¹⁰ Ω · cm. It is formed by. The low-resistance resin base material constituting this resin composition may be any material as long as it has the above-mentioned volume resistivity, and is not particularly limited. Specifically, rubber, urethane resin, acrylic resin Urethane resin, acrylic resin, ester resin, nylon resin, phenol resin, epoxy resin, fluororesin, silicone resin and the like can be mentioned, and one or more of these can be mixed and used, especially urethane resin, acrylic resin An aqueous resin such as urethane resin and acrylic resin is preferably used. In addition, the more preferable resistance value of this low resistance resin base material is 1 × 10 ⁵ to 1 × 10 ⁸ Ω · cm.

  As a conductive agent added to the low-resistance resin base material, an ion conductive material having a molecular weight of 30 to 800, preferably a molecular weight of 100 to 500 is used. As this ionic conductive material, tetradecammonium, tetrabutylammonium, dodecyltrimethylammonium such as lauryltrimethylammonium, octadecyltrimethylammonium such as hexadecyltrimethylammonium, stearyltrimethylammonium, benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, modified Ammonium perchlorate such as aliphatic dimethylethyl ammonium, chlorate, hydrochloride, bromate, iodide, borofluoride, sulfate, alkyl sulfate, carboxylate, sulfonate, etc. Organic ionic conductive materials: lithium, sodium, calcium, magnesium and other alkali metal or alkaline earth metal perchlorates, chlorates, hydrochlorides, odors Salt, iodine salt, fluoroboric acid salts, trifluoromethyl sulfate, and inorganic ion-conductive material such as a sulfonic acid salt can be exemplified, it can be used alone or in combination of two or more thereof. Among these, although not particularly limited, one or more quaternary ammonium perchlorates are particularly preferably used.

The resistance adjustment layer 3 is for adjusting the electrical resistance value of the charging roller 10, and the resistance value of the resistance adjustment layer 3 is appropriately set according to the resistance value of the elastic layer 2 and the resistance value required for the roller. However, it is usually set to 1 × 10 ³ to 1 × 10 ⁸ Ω · cm, particularly 1 × 10 ⁵ to 1 × 10 ⁷ Ω · cm. In this case, the amount of the ion conductive substance as the conductive agent is set to an appropriate amount to achieve this resistance value, but is usually 0.1 to 20 with respect to 100 parts by weight of the low resistance resin substrate. In the present invention, since the low resistance resin base material is used as the base resin of the resistance adjusting layer 3, the above-mentioned appropriate amount can be obtained with such a relatively small amount. The resistance adjustment layer 3 having a resistance value can be easily obtained.

  In addition to the ionic conductive material, an appropriate additive can be added to the resistance adjusting layer 3. For example, an oxazoline-based, epoxy-based, melamine-based, guanamine-based, isocyanate-based, or phenol-based crosslinking agent can be added. An appropriate amount can be blended depending on the low-resistance resin substrate to be used, and the film-forming aid, dispersant, thickener, leveling agent, thixotropy-imparting agent, structure can be used without departing from the purpose of the resistance adjusting layer 3. An appropriate amount of a known additive such as a viscosity-imparting agent can be blended.

  The thickness of the resistance adjusting layer 3 is appropriately selected according to the thickness of the elastic layer 2 and the form of the charging roller 10 and is not particularly limited, but is usually 10 to 500 μm, particularly 50 to 300 μm. If the thickness is less than 50 μm, it may be difficult to adjust the resistance sufficiently. On the other hand, if the thickness exceeds 300 μm, the elastic layer becomes relatively thin and the roller hardness increases. Or cost may be higher than necessary.

  Next, as a material for forming the skin layer 4, a known rubber or resin can be used, and is not particularly limited, but is a urethane-modified acrylic resin, polyurethane resin, acrylic resin, polyamide resin, and fluorine resin. Etc., and one or more of these may be used in combination. Among these, a fluororesin is particularly preferably used. By using the fluororesin, good low friction property and toner adhesion (non-adhesion) can be achieved.

  Specific examples of the fluororesin include polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymer. And tetrafluoroethylene-vinylidene fluoride copolymer, polyvinylidene fluoride, and polyvinyl fluoride.

  Further, the resin forming the skin layer 4 is not particularly limited, but the conductivity (electric resistance) of the skin layer can be imparted or adjusted by adding a conductive agent. In this case, the conductive agent is not particularly limited, but various electronic conductive agents, various ionic conductive agents, and carbon are preferably used.

The addition amount of the conductive agent can be appropriately adjusted so that a desired resistance is obtained. In this case, the resistance of the skin layer 4 is preferably 1 × 10 ⁴ to 1 × 10 ¹² Ω · cm, particularly 1 × 10 ⁶ to 1 × 10 ⁸ Ω · cm. The addition amount of the conductive agent can be adjusted so as to achieve the rate, and the addition amount when carbon is used as the conductive agent is usually about 1 to 100 phr, particularly about 10 to 70 phr with respect to the base resin. The

  In addition, additives, such as a crosslinking agent, a thickener, a thixotropy imparting agent, and a structural viscosity imparting agent, can be added to the resin composition forming the skin layer 4 as necessary.

  The thickness of the skin layer 4 is not particularly limited, but is usually 1 to 30 μm, particularly 1 to 20 μm, and if it is less than 1 μm, the durability of the roller may be inferior, If it exceeds 20 μm, good surface properties may not be obtained, for example, the charging characteristics may be adversely affected or the surface may be wrinkled.

  The charging roller 10 manufactured according to the present embodiment has the resistance adjustment layer 3 and the skin layer 4 formed on the elastic layer 2, and between the elastic layer 2 and the resistance adjustment layer 3 as necessary. In addition, another layer may be interposed between the resistance adjustment layer 3 and the skin layer 4. For example, an adhesive layer having a thickness of about 1 to 50 μm can be provided between the elastic layer 2 and the resistance adjustment layer 3 in order to firmly bond both layers. In this case, the adhesive layer can be formed by applying a paint containing a resin material such as acrylic resin, urethane resin, acrylic urethane resin, polyester resin, polyamide resin or the like on the elastic layer 2 by a dipping method or the like. If necessary, a conductive agent and other additives can be added.

  As an example of a method for manufacturing a charging roller for coagulating latex to form a layer, an example in which the latex coagulation method is applied to the resistance adjustment layer 3 will be described below. FIG. 2 is a process diagram showing a process of manufacturing the charging roller 10 using this method. This manufacturing process includes a shaft supply process 21 for preparing and supplying the shaft 1, and a mold having the shaft 1 inserted therein. Elastic layer molding step 22 for forming elastic layer 2 by injecting rubber or urethane foam, resistance adjustment layer forming step 24 for forming resistance adjustment layer 3 by dip coagulation of rubber latex on the radially outer side of elastic layer 2, resistance The skin layer forming step 26 for forming the skin layer 4 by dipping the coating material radially outside the adjustment layer 3 and the skin layer drying step 27 for forcibly drying the skin layer are provided, and the last skin layer drying step 27 is completed. The charged roller 10 is moved to the next process, for example, an inspection process.

  The resistance adjustment layer forming step 24 includes six steps shown in FIG. That is, first, in the latex undercoating step 24a, a charging roller having an elastic layer 2 formed on the shaft 1 is immersed in a latex dip tank that contains a latex solution emulsified in water. In addition, after the latex was primed, in the coagulant dip coating step 24b, the tip of the charging roller consisting of the shaft tip and the elastic layer tip was masked with a masking tape in the coagulant dip tank containing the coagulant solution. The elastic roller is immersed, the pre-charged charging roller is immersed, and the coagulant is dip-coated on the outside of the elastic layer 2 to form a coagulant layer. Here, the undercoat latex functions as an adhesive for adhering the coagulant to the elastic layer 2. Here, without providing the latex undercoating step 24a, the coagulant may be dip coated directly on the peripheral surface of the elastic layer 2, and the necessity of the latex undercoating step 24a depends on the layer formed by the latex coagulation method and the inside thereof. It can be determined by the quality of the adhesion with the layer adjacent to.

  Air is applied to the charging roller on which the coagulant layer is formed and dried at room temperature, and then the masking tape is peeled off to expose the tip of the charging roller. Next, in the latex dip coating step 24c, this is placed in a latex dip tank. Immerse. At this time, the acidic coagulant and the alkali latex cause an acid-alkali reaction, and the latex is gelled and coagulated with the acid-alkali reaction. Thus, in this latex coagulation method, the resistance adjusting layer 3 is formed by reaction with the coagulant, so that the cross-sectional shape of the coagulant layer formed around the shaft 1 can be formed with high accuracy. It is important in forming the accurate resistance adjusting layer 3, and conversely, the dimensions of the resistance adjusting layer 3 can be adjusted by changing the thickness and cross-sectional dimensions of the coagulant layer. In order to change the thickness and cross-sectional dimensions of the coagulant layer, the concentration of the coagulant may be changed, or the dipping conditions such as the pulling speed when pulling up the roller from the dip tank may be changed.

  After the latex dip coating process 24c, in order to remove the water generated by the acid-alkali reaction, in the low-temperature drying process 24d, the temperature of the roller during formation is kept at, for example, about 40 ° C., and then the acid-alkali reaction is performed. In order to remove the salt generated in step 1, the substrate is washed with water having a low salt concentration in the washing step 24e. If this salt is not removed, it remains in the charging roller as a foreign substance, and deposits on the surface of the charging roller during use, causing contamination of the photoreceptor.

  4A and 4B are cross-sectional views showing the leading end of the charging roller before and after the cleaning step 24e. FIG. 4A shows a state before cleaning, and FIG. In this washing step 24e, unreacted latex is also removed in addition to salt, but the coagulation agent 15 that extends around the elastic layer 2 is coagulated at the tip of the charging roller 10A before washing. A reacted latex layer 16 is formed as shown in FIG. 4 (a), and this latex layer 16 is not only radially outward of the coagulant layer 15 but also axially outward from the end of the coagulant layer 15. Further, salt and unreacted latex 17 are attached to the outer side so as to cover the coagulated and reacted latex layer 16 and the shaft 1.

  In the cleaning step 24e, the salt and unreacted latex 17 are removed to leave only the latex layer 16 that has undergone the coagulation reaction and to expose the tip of the shaft 1 as shown in FIG. 4 (b). Can do. The exposed length Da of the shaft portion can be determined by setting the position of the coagulant layer in the longitudinal direction, for example, the position of Db from the end of the shaft 1. This is an example in which this is set according to the attachment position of the masking tape.

  As a setting method of the position of the end portion in the length direction of the coagulant layer 15, in addition to the method using the masking tape, the coagulant is dip-coated without applying the masking tape, and after coating, the predetermined length of the tip portion of the charging roller 10A is set. It can also be done by washing or wiping off the part.

  Furthermore, as another example of the method for setting the position of the end portion in the longitudinal direction of the coagulant layer, instead of dip coating in which the tip end portion of the charging roller 10A is inevitably painted, a coating in which the coagulant is melted with a roll coater. It is also possible to use a method of coating the surface of the shaft with the working fluid. In this case, the position of the end in the length direction of the coagulant layer 15 can be set by setting the coating region at both ends in the length direction.

  After the cleaning step 24e, the charging roller 10A is transferred to the high temperature drying step 24f to complete the formation of the resistance adjusting layer 3. In this step, latex is vulcanized in addition to evaporating moisture. Therefore, for example, drying is performed at a high temperature of about 70 to 80 degrees.

  Examples of the adjustment of the coating material in the latex dip coating step 24c include those shown in the following (Paint Adjustment Example A) and (Paint Adjustment Example B). In this case, latex coagulation in the coagulant dip coating step 24b is possible. Examples of the liquid include those prepared by mixing a coagulant (coal latex 93: manufactured by Kawaguchi Chemical Industry Co., Ltd.): 50 parts by mass and methanol: 50 parts by mass with a stirring blade to adjust the coagulation liquid. .

(Paint adjustment example A)
Rubber latex (JSR0561: manufactured by JSR Corporation): 100 parts by mass, carbon black (MA100: manufactured by Mitsubishi Chemical Co., Ltd.): 10 parts by mass, colloidal sulfur (colloidal sulfur: manufactured by Hosoi Chemical Co., Ltd.): 2 parts by mass Part and a thickener (SN thickener A-815: manufactured by San Nopco Co., Ltd.): 1 part by mass are mixed with a stirring blade.

(Paint adjustment example B)
Rubber latex (JSR0561: manufactured by JSR Corporation): 100 parts by mass, carbon black (MA100: manufactured by Mitsubishi Chemical Co., Ltd.): 10 parts by mass, colloidal sulfur (colloidal sulfur: manufactured by Hosoi Chemical Co., Ltd.): 2 parts by mass parts, and, foaming agents (FR25: manufactured by Kao Corp.): 0.5 part by mass, mixing the high Hayaawa freshly stirrer, to adjust the form paint foam density 0.4 g / cm @ 3.

  In the above formulation examples, carbon black is used as the conductive agent, but there is no problem even if an ionic conductive agent is used instead.

  When the thickness of the resistance adjustment layer 3 is, for example, 300 μm, in the conventional dip coating, it is necessary to repeat the step of dipping the paint and the step of drying it about 5 to 10 times each. By forming the resistance adjusting layer 3 by coagulating rubber latex, it can be completed by a single dipping operation, and productivity can be greatly improved.

  It is important for the charging roller to form a uniform contact surface in the length direction when pressed against the photosensitive drum. Therefore, it is preferable that the center portion in the length direction has a crown shape having a diameter larger than that of the end portion. FIG. 5 is a cross-sectional view showing the charging roller 20 having a cross section formed in a crown shape by making the central portion in the length direction of the resistance adjusting layer 13 thicker than both ends, and is formed around the shaft 1 in the figure. The thicknesses of the elastic layer 12 and the skin layer 14 are uniformly formed over the length direction.

  FIG. 6 is a side view of the coagulant dip tank 9 showing a state in the middle of forming the resistance adjusting layer 13 by pulling up the shaft 1 from the coagulant solution, and forming the elastic layer 12 suspended from the hanger 8. By changing the pulling speed when pulling up the finished shaft 1 from the coagulant solution 6 according to the pulling position, the adhesion amount of the coagulant solution to become the resistance adjusting layer 13 is thickened at the central portion in the length direction. The cross-sectional shape of the coagulant is formed in a crown shape by controlling the thickness of the coagulant so that the resistance adjusting layer 13 is finished in a cross-sectional crown shape by immersing the roller with the coagulant adhering to the crown shape in latex. it can. In this case, it is not necessary to change the thickness of the skin layer 14 in the length direction. If the thickness of the skin layer 14 is thick at the center in the length direction and thin at the end, the crown-shaped elastic roller 20 is formed. When formed, it is possible to prevent variation in the length direction of electrical characteristics that may occur because the skin layer 14 is a thin layer.

  As described above, the charging roller manufacturing method has been described by taking the charging rollers 10 and 20 as an example. However, for other elastic rollers, the required layer can be formed by coagulating rubber latex. Obtainable.

  This elastic roller manufacturing method can be applied to a roller made of a plurality of layers and made of high-precision rubber or resin used in an electrophotographic apparatus, in addition to a charging roller.

It is sectional drawing of the charging roller used as the typical example of the elastic roller formed by the manufacturing method of embodiment which concerns on this invention. It is process drawing which shows the flow of the process which manufactures a charging roller. It is a partial process figure at the time of forming an elastic layer by the latex coagulation method. It is sectional drawing of the shaft front-end | tip part before and behind a washing | cleaning process. It is sectional drawing which shows the charging roller which has a crown shape. It is a side view of the dip tank which shows the state in the middle of pulling up a shaft from a solution and forming an elastic layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 2, 12 Elastic layer 3, 13 Resistance adjustment layer 4, 14 Skin layer 6 Solution 7 Elastic layer in formation 8 Hanger 9 Coagulant dip layer 10, 10A Charging roller 15 Coagulant layer 16 Latex layer 17 after coagulation reaction Unreacted latex 21 Shaft supply process 20 Charging roller 22 Elastic layer molding process 24 Resistance adjustment layer dip coating process 24a Latex undercoating process 24b Coagulant dip coating process 24c Latex dip coating process 24d Low temperature drying process 24e Cleaning process 24f Low temperature drying process 26 Skin layer dip coating process 27 Skin layer drying process

Claims (7)

In the method for producing an elastic roller in which one or more layers are arranged outside the elastic layer provided around the shaft,
Of the layers arranged outside the elastic layer, at least one layer is formed by coagulating rubber latex ,
The step of coagulating rubber latex to form the layer includes a step of forming a coagulant layer made of a coagulant having a predetermined thickness, and a step of dip-coating the rubber latex around the coagulant layer to coagulate the rubber latex. A method of manufacturing an elastic roller, wherein the thickness of the layer made of rubber latex is adjusted by changing the thickness of the coagulant in the step of forming the coagulant layer. The method for producing an elastic roller according to claim 1 , wherein the layer made of rubber latex is finished in a cross-sectional crown shape by making the thickness of the central portion of the coagulant in the shaft length direction thicker than both ends. After the step of coagulating the rubber latex, there is provided a cleaning step for removing the salt produced in this step and the deposit made of unreacted rubber latex from the elastic roller, and after removing the deposit, a predetermined process is performed. The method for producing an elastic roller according to claim 1 or 2 , wherein the end position in the length direction of the coagulant layer is set before the rubber latex is coagulated so that the shaft end surface of the length is exposed. The elastic roller is immersed in a dip tank containing a coagulant to form the coagulant layer, and by wiping off a predetermined length portion of the coagulant adhering to the elastic roller tip including the shaft tip, The elastic roller manufacturing method according to claim 3 , wherein the position of the end portion in the length direction of the coagulant layer is set. The elastic roller is immersed in a dip tank containing a coagulant to form the coagulant layer, and a predetermined length portion of the coagulant adhering to the elastic roller tip including the shaft tip is washed and removed. The method for producing an elastic roller according to claim 3 , wherein the position of the end portion in the length direction of the coagulant layer is set by: The elastic roller is immersed in a dip tank containing a coagulant to form the coagulant layer, and a predetermined length portion of the elastic roller tip including the shaft tip is masked with a masking tape prior to the immersion, The method for producing an elastic roller according to claim 3 , wherein the end position of the coagulant layer in the length direction is set by removing the masking tape after the immersion. The coagulant coating liquid is applied to the surface of the elastic roller with a roll coater to form the coagulant layer, and by adjusting the coating area in the roll coater coating, the end position in the length direction of the coagulant layer The manufacturing method of the elastic roller of Claim 3 which sets these.

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