JP2013214079A - Device for manufacturing conductive roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for manufacturing a conductive roll which suppresses filming of an electrifying member and/or a photoreceptor and improves distortion characteristics of the electrifying member so that a stripe defect can be suppressed.SOLUTION: A device 300 for manufacturing a conductive roll includes: a metal mold 50 including a space 54 for the formation of an elastic layer into which a conductive elastic material 12 is injected or charged, a support part 52 for supporting a shank 20b of a core bar 20 along the longitudinal direction of the space 54, a charging port (not shown) for allowing the elastic material to be charged into the space 54, and a metal mold housing part 56 having a cooler; and a heater 40 attached to the shank 20b of the core bar 20 projecting from the support part 52 of the metal mold 50.

Description

  The present invention relates to an apparatus for manufacturing a conductive roll used in an electrophotographic or electrostatic recording process in an image forming apparatus such as an electrophotographic copying machine or a printer.

  Conventionally, in image forming apparatuses such as copying machines and printers employing an electrophotographic method, those using a corona discharge phenomenon such as a scorotron charger as a charging device have been widely used. In such a charger, Ozone and nitrogen oxides are generated that may adversely affect the human body and the global environment.

  Therefore, as a charging device used in an electrophotographic image forming apparatus, contact with which a conductive charging member is directly contacted and charged with an electroconductive charging member with extremely little generation of harmful ozone and nitrogen oxide is used. The electrification type is mainly used. In this case, since the toner is in contact with the photosensitive member, the transfer residual toner and the toner external additive slip through the image holding member cleaning member, and the transfer residual toner and the toner external additive are rubbed between the charging member and the image holding member. In other words, so-called filming also occurs on the image carrier in the charging member. When this filming occurs, the electrical resistance increases at the filming portion of the charging member, and the filming portion of the image carrier significantly deteriorates the photosensitive characteristics, so that density unevenness may occur at the filming portion.

  Recently, there is a tendency for density unevenness due to filming to become apparent as color, image quality, and lifespan increase. Such filming of the charging member and / or the photosensitive member is caused by the toner and / or the external additive being ground at the contact portion due to the high pressing of the contact portion. In order to avoid this, a method has been devised in which fillers and particles are added to the outer peripheral layer (surface layer), or the outer layer (surface layer) has a low hardness by foaming (for example, see Patent Documents 1 and 2). .

  However, when the load concentrates on the convex portion of the filler, a sufficient effect cannot be obtained, and when the filler is poorly dispersed, white spots and color spots are generated. Further, simply by making the outer peripheral layer of the charging roll low in hardness, the distortion characteristics of the charging roll due to compression are deteriorated and streaks are generated in the axial direction of the charging roll. On the other hand, in order to maintain the distortion characteristics, 2 Although the structure with the elastic layer of a layer is also considered, the subject that a preparation process is complicated and expensive arises. In addition, if the outer peripheral layer of the charging roll is simply made to have a low hardness, the polishing property of the charging roll surface is significantly deteriorated. In the contact charging method that requires ensuring, sufficient image quality may not be obtained.

JP 2006-10754 A JP-A-6-202442

  An object of the present invention is to provide a conductive roll manufacturing apparatus capable of suppressing filming of a charging member and / or a photoreceptor, improving distortion characteristics of the charging member, and suppressing streak defects.

  The above-mentioned subject is achieved by the following present invention. That is, the conductive roll manufacturing apparatus of the present invention has the following characteristics.

  (1) An electroconductive roll provided with a mold having a space for forming an elastic layer, a support part for supporting a cored bar passing in the longitudinal direction of the space, and a filling port for filling the space with an elastic material. In this manufacturing apparatus, a cooling device is provided in the mold, and further, a heating device that is attached to a core metal protruding from the support portion is provided.

  (2) A conductive roll provided with a mold having a space for forming an elastic layer, a support part for supporting a core metal that passes in the longitudinal direction of the space, and a filling port for filling the space with an elastic material. In this manufacturing apparatus, a heating device is provided in the mold, and further, a cooling device for mounting on a core bar protruding from the support portion is provided.

  According to the present invention, the hardness of the conductive elastic layer of the conductive roll has a hardness gradient in the thickness direction, the hardness of the conductive roll on the conductive axis side is high, and the hardness is directed toward the surface side of the conductive roll. When the hardness of the conductive roll is low, the vicinity of the outer periphery of the conductive roll has a low hardness. Therefore, when the conductive roll is used as a charging member, the effect of reducing the pressing force between the charging member and the photosensitive member is manifested. Further, filming of the external additive is prevented, and thereby, density unevenness of the image is suppressed. Further, since the hardness is high toward the center of the conductive roll and it is sufficiently vulcanized, the distortion characteristics are not impaired and the generation of streak defects due to distortion is suppressed. Furthermore, since it can be realized in the same layer of the conductive elastic body layer, there is no need to laminate an elastic layer as in the past, and an inexpensive conductive roll and an inexpensive conductive roll are provided compared to the conventional one. An inexpensive image forming apparatus can be provided.

  Further, according to the present invention, the hardness of the conductive elastic layer of the conductive roll has a hardness gradient in the thickness direction, the hardness of the conductive roll on the conductive axis side is low, and the surface of the conductive roll is on the surface side. When the hardness is higher, the vicinity of the outer periphery is highly hard and densely vulcanized, so the surface of the conductive roll is excellent in abrasiveness, that is, the shape of the conductive roll can be controlled such as runout. It can be easily performed, and since the hardness has a hardness gradient in the thickness direction, it has excellent distortion characteristics, and the hardness decreases as it goes to the shaft core, so it has the effect of reducing the pressing force between the charging member and the photoreceptor. And filming due to the external additive of the toner is prevented. Furthermore, since it can be realized in the same layer of the conductive elastic body layer, there is no need to laminate an elastic layer as in the past, and an inexpensive conductive roll and an inexpensive conductive roll are provided compared to the conventional one. An inexpensive image forming apparatus can be provided.

It is a cross-sectional view which shows an example of a structure of the electroconductive roll of 1st reference embodiment in this invention. It is a cross-sectional view which shows an example of a structure of the electroconductive roll of 2nd reference embodiment in this invention. It is a cross-sectional view which shows an example of a structure of the manufacturing apparatus of the electroconductive roll of 1st Embodiment in this invention. It is a cross-sectional view which shows an example of a structure of the manufacturing apparatus of the electroconductive roll of 2nd Embodiment in this invention. 1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus according to a reference embodiment of the present invention.

  Embodiments of the present invention will be described below. In describing the embodiment of the present invention in detail, the conductive roll in the reference embodiment will be described in detail first, and then the method and apparatus for manufacturing the conductive roll in the present embodiment, and the present invention will be described. An image forming apparatus according to a reference embodiment of the invention will be described. The conductive roll according to the present embodiment is not limited to the charging roll, and other forms are allowed.

<Conductive roll>
As shown in FIG. 1, the conductive roll according to the first embodiment of the present invention has a conductive elastic layer 10 concentrically around the outer periphery of the layer forming portion 20a of the cored bar 20 which is a conductive axis. A conductive roll 100 that contacts the charged body in a state where a voltage is applied and charges the charged body, and the conductive roll 100 has a hardness of the conductive elastic layer 10 in the thickness direction T. It has a hardness gradient g ₁ , and the hardness is higher on the conductive axis side of the conductive roll 100 and lower toward the surface side of the conductive roll 100.

Further, in consideration of prevention of contamination on the photosensitive member and formation of a uniform nip, the conductive roll according to the second embodiment of the present invention is used for forming a layer of a core 20 as shown in FIG. A conductive roll 110 having a conductive elastic layer 10 concentrically on the outer periphery of the portion 20a, which contacts a member to be charged in a state where a voltage is applied, and charges the member to be charged. The hardness of the conductive elastic layer 30 has a hardness gradient g ₂ in the thickness direction T, and the hardness is lower on the conductive axis side of the conductive roll 110 and higher toward the surface side of the conductive roll 110. ing.

  In the conductive rolls 100 and 110 of the first and second reference embodiments shown in FIGS. 1 and 2, the hardness difference between the surface and the axial center is preferably 1 ° to 9 °, more preferably 3 ° to 6 °. preferable. When the hardness difference is 10 ° or more, the surface is hardly vulcanized, the surface side extremely loses the rubber elasticity, and the distortion is remarkably deteriorated so that the generation of streaks becomes remarkable.

  Further, the total runout in the conductive roll 110 of the second reference embodiment shown in FIG. 2 is 0.1 mm or less, preferably 0.08 mm or less, more preferably 0.05 mm or less. Further, the ten-point average roughness Rz of the conductive elastic layer 30 shown in FIG. 2 is 5 μm or less, preferably 4.5 μm or less, more preferably 3.5 μm or less. A method for measuring the total runout and the ten-point average roughness Rz will be described later.

  The conductive cored bar 20 of the conductive rolls 100 and 110 of the first and second reference embodiments shown in FIGS. 1 and 2 functions as an electrode and a support member of the conductive roll. For example, aluminum , Copper alloy, stainless steel or other metal or alloy; chromium or nickel plated iron; conductive resin;

  The conductive elastic layers 10 and 30 of the first and second reference embodiments shown in FIGS. 1 and 2 are formed, for example, by dispersing a conductive agent in a rubber material. Rubber materials include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, polyurethane, fluoro rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether. Examples thereof include copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), silicone rubber, natural rubber, and blend rubbers thereof. Among these, polyurethane, EPDM, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, NBR, and blended rubbers thereof are preferably used. These rubber materials may be foamed or non-foamed.

  Moreover, as a conductive agent added to the conductive elastic layers 10 and 30 shown in FIGS. 1 and 2, an electronic conductive agent or an ionic conductive agent is used. Examples of electronic conductive agents include carbon blacks such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, and stainless steel; tin oxide, indium oxide, titanium oxide Examples thereof include fine powders such as various conductive metal oxides such as tin oxide-antimony oxide solid solution and tin oxide-indium oxide solid solution; Examples of ionic conductive agents include perchlorates and chlorates such as tetraethylammonium and lauryltrimethylammonium; alkali metals such as lithium and magnesium; perchlorates and chlorates of alkaline earth metals Can be mentioned. What is necessary is just to adjust to arbitrary resistance by disperse | distributing these, and if resistance can be obtained arbitrarily, there will be no limitation in particular. Also, two or more of these conductive agents can be used in combination.

  As an example of the charging rolls of the conductive rolls 100 and 110, an intermediate layer or a surface layer may be used on the outer periphery of the conductive elastic layers 10 and 30 in order to increase the functionality such as uniform resistance and surface protection. Moreover, in order to acquire effects, such as tack prevention and bleed prevention, you may comprise the layer which consists of 1 or more layers of resin on the outer periphery of a conductive elastic layer as needed.

  The polymer material constituting the surface layer is not particularly limited, but is polyamide, polyurethane, polyvinylidene fluoride, tetrafluoroethylene copolymer, polyester, polyimide, silicone resin, acrylic resin, polyvinyl butyral, ethylene tetrafluoroethylene. Examples thereof include copolymers, melamine resins, fluororubbers, epoxy resins, polycarbonates, polyvinyl alcohol, cellulose, polyvinylidene chloride, polyvinyl chloride, polyethylene, and ethylene vinyl acetate copolymers.

  Among these, polyamide, polyvinylidene fluoride, tetrafluoroethylene copolymer, polyester, and polyimide are preferably used from the viewpoint of releasability with toner and the like. The above polymer materials may be used alone or in combination of two or more. Further, the number average molecular weight of the polymer material is preferably in the range of 1,000 to 100,000, and more preferably in the range of 10,000 to 50,000.

  The surface layer is formed as a composition by mixing the polymer material with the conductive agent used in the conductive elastic layers 10 and 30 and various fine particles. Examples of the conductive agent and various fine particles include carbon blacks such as ketjen black and acetylene black; metal oxides such as pyrolytic carbon, graphite, silicon oxide, aluminum oxide, and barium titanate, and composite metal oxides, tetrafluoroethylene, Polymer fine powders such as vinylidene fluoride can be used alone or as a mixture, but are not particularly limited thereto.

  The amount of the conductive material and fine particles blended as the composition of the surface layer is preferably in the range of 3% by mass to 120% by mass in the entire composition of the surface layer, and is preferably 5% by mass to 50% by mass. The following range is more preferable.

  The thickness of the surface layer is not particularly limited, but is preferably 20 μm or less, and more preferably 15 μm or less.

<Conductive roll manufacturing apparatus and manufacturing method>
FIG. 3 shows an outline of the configuration of an example of an apparatus for manufacturing the conductive roll 100 according to the first embodiment of the present invention. As shown in FIG. 3, the conductive roll manufacturing apparatus 300 includes an elastic layer forming space 54 into which the conductive elastic material 12 is injected or filled, and a shaft portion of the core metal 20 that passes in the longitudinal direction of the space 54. A mold 50 having a support portion 52 that supports 20b, a filling port (not shown) that fills the space 54 with an elastic material, and a mold housing portion 56 that includes a cooling device, and a support for the mold 50 Heating devices 40 that are respectively attached to both ends of the shaft portion 20 b of the cored bar 20 protruding from the portion 52 are provided. The manufacturing apparatus 300 may have an apparatus configuration that includes one or more mold accommodating portions 56, each of which is partitioned and capable of manufacturing a plurality of conductive rolls at the same time.

  As the cooling device in the first embodiment, a constant temperature water circulation device (chiller) can be used. As an example of the cooling device, as shown in FIG. The mold surface can be cooled, and an external cooler (not shown) for cooling the cooling water to be circulated is provided outside the mold 50. Here, the cooling water circulation channel 58 is provided meandering, for example, in order to uniformly cool the surface of the mold 50 facing the space 54. As the heating device 40, for example, an electromagnetic dielectric heating device (IH device) including an electromagnetic induction coil 42 is used. When the conductive roll is a charging roll, the elastic layer forming space 54 of the mold 50 is a cylindrical space.

  A method for manufacturing the conductive roll 100 using the above-described conductive roll manufacturing apparatus 300 will be described below with reference to FIG. First, the uncured conductive elastic material 12 is filled into the cylindrical space 54 of the mold 50 through a filling port (not shown). Then, after the conductive elastic material 12 is filled in the space 54, current is applied to the electromagnetic induction coil 42 of the heating device 40 to heat the core metal 20, and at the same time, the cooling water circulation flow of the mold 50 is performed. Cooling water is circulated through the path 58 to cool the conductive elastic material 12 in contact with the surface of the mold housing 56. Here, the elastic material is vulcanized while maintaining the temperature difference between heating and cooling for a predetermined time according to the thickness of the conductive elastic layer, the type of elastic material, the type of vulcanizing agent, and the amount added.

  The conductive elastic layered body is formed by setting the temperature of the mold 50 facing the outer periphery of the conductive elastic layer lower than the temperature applied to the conductive axis (that is, the core metal 20) by the above manufacturing method. In spite of the same hardness and the same material, the conductive axis is high and the surface is low, and it is possible to form a conductive elastic layer having a hardness gradient in the thickness direction. When molded in this way, the vulcanization reaction starts from the conductive axis side close to the high-temperature heat source, and the vulcanization reaction slows as it goes radially to the surface side, so the vicinity of the conductive axis has a high vulcanization density, Therefore, it is possible to obtain a physical property having high hardness and excellent distortion characteristics. On the other hand, since the vulcanization density is low on the surface side, the hardness is low.

  FIG. 4 shows an outline of the configuration of an example of a manufacturing apparatus for the conductive roll 110 according to the second embodiment of the present invention. As shown in FIG. 4, the conductive roll manufacturing apparatus 310 includes an elastic layer forming space 64 into which the conductive elastic material 12 is injected or filled, and a shaft portion of the cored bar 20 that passes in the longitudinal direction of the space 64. A mold 60 having a support part 62 that supports 20b, a filling port (not shown) for filling the space 64 with an elastic material, and a mold housing part 66 equipped with a heating device; Cooling devices 70 that are respectively attached to both ends of the shaft portion 20 b of the cored bar 20 protruding from the portion 62 are provided. Note that the manufacturing apparatus 310 may have an apparatus configuration that includes one or more mold accommodating portions 66, each of which is partitioned, and that can manufacture a plurality of conductive rolls at the same time.

  As the cooling device 70 in the second embodiment, a constant temperature water circulation device (chiller) can be used. As shown in FIG. 4, a cooling circulation channel 72 is provided in the cooling device 70 and further circulated. An external cooler (not shown) for cooling the cooling water is provided. Further, as the heating device provided in the mold housing portion 66, for example, an electromagnetic dielectric heating device (IH device) including an electromagnetic induction coil 68 is used. When the conductive roll is a charging roll, the elastic layer forming space 64 of the mold 60 is a cylindrical space.

  A method for manufacturing the conductive roll 110 using the conductive roll manufacturing apparatus 310 described above will be described below with reference to FIG. First, the uncured conductive elastic material 12 is filled into the cylindrical space 64 of the mold 60 from a filling port (not shown). Then, after the conductive elastic material 12 is filled in the space 64, a current is applied to the electromagnetic induction coil 68 that is a heating device of the mold 60, and the conductive elastic material 12 in contact with the surface of the mold housing portion 66. At the same time, the cooling water is circulated through the cooling water circulation passage 72 of the cooling device 70 to cool the cored bar 20. Here, the elastic material is vulcanized while maintaining the temperature difference between heating and cooling for a predetermined time according to the thickness of the conductive elastic layer, the type of elastic material, the type of vulcanizing agent, and the amount added.

  According to the above manufacturing method, the hardness of the conductive elastic layer is the same in the same layer and the same by forming the mold 60 facing the outer periphery of the conductive elastic layer at a temperature higher than the temperature applied to the conductive axis. Regardless of the material, it is possible to form a conductive elastic layer having a low conductive axis side and a high surface side, and a hardness gradient in the thickness direction. When molded in this way, the vulcanization reaction starts from the outer peripheral side of the conductive elastic layer close to a high-temperature heat source, and the vulcanization reaction becomes slower as it goes radially toward the conductive axis, so the outer peripheral side of the conductive elastic layer Makes it possible to obtain a conductive roll having a high vulcanization density, and hence a high hardness, excellent distortion characteristics, and significantly improved abrasiveness. On the other hand, since the vulcanization density is low on the conductive axis side, the hardness is low, and the pressure on the photoreceptor as a whole is reduced.

  In the present embodiment, the manufacturing apparatus for conductive rolls in injection molding or injection molding has been described. However, the present invention is not limited to this, and an unvulcanized conductive roll precursor is manufactured and this unvulcanized conductive film is manufactured. Roll precursors may be placed in the molds 50 and 60, respectively, to change the degree of vulcanization in the thickness direction of the conductive elastic layer.

<Image forming apparatus>
Next, an image forming apparatus according to a reference embodiment of the present invention will be described in detail with reference to the drawings. An image forming apparatus according to a reference embodiment of the present invention includes a latent image holding member, a charging unit that charges the surface of the latent image holding member, a latent image forming unit that forms a latent image on the surface of the latent image holding member, An image forming apparatus comprising: a developing unit that develops the latent image with toner to form a toner image; and a transfer unit that next transfers the toner image onto a recording medium. The conductive rolls 100 and 110 according to the second reference embodiment are provided. Incidentally, as the charging rolls 402a to 402d shown in FIG. 5 described later, the first and second reference embodiments are used in accordance with purposes such as filming suppression, distortion characteristic improvement, photoconductor contamination prevention, and uniform nip formation. The conductive rolls 100 and 110 are preferably selected and used.

  FIG. 5 is a schematic diagram illustrating a configuration example of an image forming apparatus according to a reference embodiment of the present invention. In the illustrated image forming apparatus 200, four electrophotographic photosensitive members 401 a to 401 d are disposed in parallel in the housing 400 along the intermediate transfer belt 409. The electrophotographic photoconductors 401a to 401d that are latent image carriers are, for example, yellow color for the electrophotographic photoconductor 401a, magenta for the electrophotographic photoconductor 401b, cyan for the electrophotographic photoconductor 401c, and black for the electrophotographic photoconductor 401d. It is possible to form each of the images.

  Each of the electrophotographic photosensitive members 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll 410a along the rotation direction. To 410d and cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toners of four colors, yellow, magenta, cyan and black, accommodated in toner cartridges 405a to 405d, and the primary transfer rolls 410a to 410d are intermediate transfer belts, respectively. 409 is in contact with the electrophotographic photoreceptors 401a to 401d. Each of the charging rolls 402a to 402d is a contact charging roll as an example of the contact charging member described above.

  Further, an exposure device 403 is disposed at a predetermined position in the housing 400, and it becomes possible to irradiate the surfaces of the charged electrophotographic photoreceptors 401a to 401d with a light beam emitted from the exposure device 403. ing. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner.

  Here, the charging rolls 402a to 402d contact the surface of the electrophotographic photoreceptors 401a to 401d with a conductive member (charging roll), and apply a voltage uniformly to the photoreceptor to charge the photoreceptor surface to a predetermined potential. (Charging process). In addition to the charging roll shown in this embodiment, charging is performed by a contact charging method using a charging brush, a charging film, a charging tube, or the like.

  As the exposure apparatus 403, an optical system apparatus or the like that can expose a light source such as a semiconductor laser, an LED (light emitting diode), a liquid crystal shutter, or the like on the surfaces of the electrophotographic photosensitive members 401a to 401d can be used. Among these, when an exposure apparatus capable of exposing non-interference light is used, interference fringes between the electroconductive substrates of the electrophotographic photoreceptors 401a to 401d and the photosensitive layer can be prevented.

  For the developing devices 404a to 404d, a general developing device that develops the developer for developing the two-component electrostatic charge image in contact or non-contact can be used (developing step). Such a developing device is not particularly limited as long as a two-component electrostatic image developing developer is used, and a known one can be appropriately selected according to the purpose.

  In the primary transfer step, a primary transfer bias having a polarity opposite to that of the toner carried on the image carrier is applied to the primary transfer rollers 410a to 410d, so that each color toner is transferred from the image carrier to the intermediate transfer belt 409. The primary transfer is performed sequentially.

  The cleaning blades 415a to 415d are for removing residual toner adhering to the surface of the electrophotographic photosensitive member after the transfer process, and the electrophotographic photosensitive member cleaned by this cleaning process is repeatedly used in the above-described image forming process. Is done. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  The intermediate transfer belt 409 is supported with a predetermined tension by a drive roll 406, a back roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. The secondary transfer roll 413 is disposed so as to contact the back roll 408 via the intermediate transfer belt 409.

  By applying a secondary transfer bias having a reverse polarity to the toner on the intermediate transfer member to the secondary transfer roll 413, the toner is secondarily transferred from the intermediate transfer belt to the recording medium. The intermediate transfer belt 409 that has passed between the back roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed near the drive roll 406 or a static eliminator (not shown). It is repeatedly used for the next image forming process. In addition, a transfer medium accommodating portion 411 is provided at a predetermined position in the housing 400, and the transfer medium 500 such as paper in the transfer medium accommodating portion 411 is secondary-transferred between the intermediate transfer belt 409 and the secondary transfer belt 412. After being sequentially transferred between the transfer roll 413 and between the two fixing rolls 414 in contact with each other, the paper is discharged outside the housing 400.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “part” represents “part by mass”.

<Example 1>
(Preparation of conductive roll)
-Formation of elastic layer-
The manufacturing apparatus shown in FIG. 3 was used in which cooling water was circulated through a mold housing portion of a cylindrical mold having an inner diameter of 14.0 mm and the axis could be heated by an electromagnetic induction coil. In producing the conductive roll, the following mixture is kneaded with an open roll, and a conductive cored bar having a diameter of 8 mm obtained by electroless nickel plating on the SUM material is used, and the cylindrical shape is adjusted to have a rubber thickness of 3 mm. Cast into mold. The output of the electromagnetic induction coil was controlled so that the temperature of the conductive core metal was always 170 ° C., and the cooling water temperature circulating outside the mold was set to 10 ° C. This was vulcanized for 25 minutes to obtain a cylindrical conductive elastic layer A taken out from the mold.

Rubber material: 100 parts by mass (Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber: Gechron 3106: 95%, acrylonitrile butadiene rubber: Nipol 1312: 5%: manufactured by Zeon Corporation)
・ Carbon black (# 3030B: manufactured by Mitsubishi Carbon Black) ・ ・ 15 parts by mass ・ Ionic conductive agent ・ ・ ・ ・ 1 part by mass (benzyltriethylammonium chloride: manufactured by Kanto Chemical Co., Inc.)
・ Vulcanizing agent ((sulfur) 200 mesh: manufactured by Tsurumi Chemical Co., Ltd.) ・ ・ ・ ・ 1 part by mass ・ Vulcanization accelerator (Noxeller DM: manufactured by Ouchi Shinsei Chemical Co., Ltd.) ・ 2.0 parts by mass Sulfur accelerator (Noxeller TT: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) ・ 0.5 parts by mass ・ Zinc oxide (Zinc Hana No. 1 manufactured by Shodo Chemical Co., Ltd.) ・ ・ ・ ・ 5 parts by mass ・ Calcium carbonate (white SSB: Calcium Shiroishi) ... 30 parts by mass

-Formation of surface layer-
Dispersion A obtained by dispersing the following mixture with a bead mill is diluted with methanol, applied to the surface of the conductive elastic layer A for convenient adjustment of initial coating speed and acceleration, and then heated at 120 ° C. for 15 minutes. It dried and formed the surface layer of thickness 5 micrometers, and the electroconductive roll 1 was obtained.

・ Polymer material: 100 parts by mass (copolymerized nylon) Alamine CM8000: manufactured by Toray Industries, Inc .: Conductive agent: 14 parts by mass (carbon black) MONARCH1000: manufactured by Cabot Corporation: Solvent (methanol): 500 parts by mass・ Solvent (butanol): 240 parts by mass

(Evaluation of conductive roll)
About the conductive elastic layer A, the conductive elastic layer is peeled off from the surface of the roll-shaped elastic layer and the shaft surface, and both ends of the shaft are 20 mm in hardness and three places in the center are MD1 hardness in a normal environment of 22 ° C. and 55% RH. The total was measured with a total of three points.

-Actual machine evaluation-
Color copier DocuCentre Color 400CP shown in FIG. 5 as conductive roll 1 is mounted on Fuji Xerox Co., Ltd., and color toners (cyan toner, magenta toner, yellow toner, black toner) for color copier DocuCentre Color 400CP are used. , A4 paper 50,000 sheet printing test (after printing 25,000 sheets at 10 ° C., 15% RH environment, 25,000 sheets printing at 28 ° C., 85% RH environment). If a major problem occurred during the process, printing was stopped at that time.

In the image quality evaluation, the image after running 50,000 sheets was visually determined based on the following criteria based on the presence or absence of density unevenness in the halftone image.
A: No defect such as density unevenness.
○: Very slight density unevenness occurred.
Δ: Minor density unevenness occurred.
X: Density unevenness that cannot be actually used occurs.

-Storage evaluation-
The conductive roll 1 is set as a charging roll on a drum cartridge and left in a 45 ° C., 95% environment for one month, and then a halftone image is output in a normal environment using the above-mentioned copying machine. The presence or absence of streaks of the charging roll pitch in the image was visually evaluated. The results are summarized in Table 1.
◎: No streak defect.
○: Extremely slight streaks are generated.
Δ: Minor streaks are generated.
×: A streak that cannot be actually used is generated.

<Example 2>
A conductive elastic layer B was produced in the same manner as in Example 1 except that the cooling water temperature was changed to 25 ° C., a surface layer was formed in the same manner as in Example 1, and a conductive roll 2 was obtained. The results are summarized in Table 1.

<Example 3>
A conductive elastic layer C was produced in exactly the same manner as in Example 1 except that the cooling water temperature was changed to 60 ° C., a surface layer was formed in the same manner as in Example 1, and a conductive roll 3 was obtained. The results are summarized in Table 1.

<Example 4>
A conductive elastic layer D was prepared in exactly the same manner except that the cooling water was not circulated and the vulcanization time in Example 1 was changed to 20 minutes. Roll 4 was obtained. The results are summarized in Table 1.

<Comparative Example 1>
Except that the cooling water temperature was changed to 5 ° C. and the vulcanization time was changed to 18 minutes, a conductive elastic layer E was produced in the same manner as in Example 1, and the surface layer was formed in the same manner as in Example 1, and the conductivity was increased. Roll 5 was obtained. The results are summarized in Table 1.

<Comparative example 2>
A conductive elastic layer F was produced in the same manner as in Example 1 except that the electromagnetic induction coil and cooling water were not used in the molding method of Example 1 and cast molding was performed using a normal mold. A surface layer was formed in the same manner as 1 to obtain a conductive roll 6. The results are summarized in Table 1.

<Example 5>
(Preparation of conductive roll)
-Formation of elastic layer-
The manufacturing apparatus shown in FIG. 4 was used in which the mold housing part of a cylindrical mold having an inner diameter of 14.5 mm was heated with an electromagnetic induction coil so that the conductive shaft could be cooled with cooling water. In producing the conductive roll, the following mixture is kneaded with an open roll, and a conductive cored bar having a diameter of 8 mm obtained by electroless nickel plating on the SUM material is used, and the cylindrical shape is adjusted to have a rubber thickness of 3 mm. Cast into mold. The output of the electromagnetic induction coil was controlled so that the temperature of the cylindrical mold was always 170 ° C., and the cooling water temperature for cooling the conductive core metal was set to 10 ° C. This was vulcanized for 25 minutes, cooled, removed from the mold, and cut and polished with a polishing machine to obtain a cylindrical conductive elastic layer G having a diameter of 14.0 mm.

Rubber material: 100 parts by mass (Epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber: Gechron 3106: 95%, acrylonitrile butadiene rubber: Nipol 1312: 5%: manufactured by Zeon Corporation)
・ Carbon black (# 3030B: manufactured by Mitsubishi Carbon Black) ・ ・ 15 parts by mass ・ Ionic conductive agent ・ ・ ・ ・ 1 part by mass (benzyltriethylammonium chloride: manufactured by Kanto Chemical Co., Inc.)
・ Vulcanizing agent ((sulfur) 200 mesh: manufactured by Tsurumi Chemical Co., Ltd.) ・ ・ ・ ・ 1 part by mass ・ Vulcanization accelerator (Noxeller DM: manufactured by Ouchi Shinsei Chemical Co., Ltd.) ・ 2.0 parts by mass Sulfur accelerator (Noxeller TT: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) ・ 0.5 parts by mass ・ Zinc oxide (Zinc Hana No. 1 manufactured by Shodo Chemical Co., Ltd.) ・ ・ ・ ・ 5 parts by mass ・ Calcium carbonate (white SSB: Calcium Shiroishi) ... 30 parts by mass

-Formation of surface layer-
Dispersion G obtained by dispersing the following mixture with a bead mill is diluted with methanol, applied to the surface of the conductive elastic layer G for convenient adjustment of initial coating speed and acceleration, and heated at 120 ° C. for 15 minutes. It dried and formed the surface layer of thickness 5 micrometers, and the electroconductive roll 7 was obtained.

・ Polymer material: 100 parts by mass (copolymerized nylon) Alamine CM8000: manufactured by Toray Industries, Inc .: Conductive agent: 14 parts by mass (carbon black) MONARCH1000: manufactured by Cabot Corporation: Solvent (methanol): 500 parts by mass・ Solvent (butanol): 240 parts by mass

(Evaluation of conductive roll)
About the conductive elastic layer G, the conductive elastic layer is peeled off from the surface of the roll-shaped elastic layer from the shaft, and both ends of the shaft are 20 mm in hardness and three places in the center are MD1 hardness in a normal environment of 22 ° C. and 55% RH. The total was measured with a total of three points.

[Full run-out]
The magnitude of the total runout is determined by measuring the displacement of the distance from the reference roll to the charging roll with a laser while rotating the conductive roll, and taking the difference between the maximum and minimum values of the displacement as the runout. This was measured by measuring the above points along the lengthwise direction of the roll, and defining it as the maximum value of deflection at these measurement points. Specifically, the Asaka Riken Kogyo Co., Ltd. roll diameter measurement system ROLL2000 is used to measure and measure the conductive roll to be measured to support both ends that serve as measurement reference surfaces for circumferential runout. Riken Kogyo Co., Ltd. roll diameter measurement system set in ROLL2000, under the conditions of the rotational speed of the conductive roll 60rpm, the rotation time 5sec, the conductive roll as the object to be measured, and the knife edge installed in parallel with this conductive roll Was measured, and the circumferential run-out was determined from the fluctuation range of the distance during this 5 sec. The above measurement was performed at a total of 5 locations, 5 mm from both ends of the conductive roll, and 3 axially central portions divided into 3 parts based on the positions of 5 mm on both ends. The value obtained by taking the difference between the minimum values was taken as the total runout.

[Surface roughness Rz]
Rz is measured using a surface roughness meter surfcom 1400A (manufactured by Tokyo Seimitsu Co., Ltd.) according to JIS B0601-1994, with a measurement length of 4.0 mm, a cut-off value of 0.8, and a measurement speed of 0.30 mm / sec. Similarly, the above-mentioned three places were measured under the above conditions, and the average value was obtained.

-Actual machine evaluation-
Color copier DocuCenter Color 400CP shown in FIG. 5 as a charging roll is mounted on Fuji Xerox Co., Ltd., and color toners (cyan toner, magenta toner, yellow toner, black toner) for color copier DocuCenter Color 400CP are used. , A4 paper 50,000 sheet printing test (after printing 25,000 sheets at 10 ° C., 15% RH environment, 25,000 sheets printing at 28 ° C., 85% RH environment). If a major problem occurred during the process, printing was stopped at that time.

The image quality evaluation was performed based on the following criteria based on the presence or absence of density unevenness in the halftone image with respect to the initial image and the image after running 50,000 sheets. The initial density unevenness was described as density unevenness due to total shake in Table 2, and the density unevenness after running 50,000 sheets was described as time-dependent density unevenness due to filming in Table 2.
A: No defects such as density unevenness.
○: Very slight density unevenness occurred.
Δ: Minor density unevenness occurred.
X: Density unevenness that cannot be actually used occurs.

In the roll dirt evaluation, the roll after running 50,000 sheets was visually evaluated according to the following criteria.
A: Almost no foreign matter adhered, slight foreign matter adhered.
○: Local foreign matter adhesion.
(Triangle | delta): The whole surface slight foreign material adhesion (it becomes thin and white).
X: Foreign matter adhering to the entire surface.

-Storage evaluation-
The conductive roll 7 is set as a charging roll on a drum cartridge, left in a 45 ° C., 95% environment for one month, and then a halftone image is output in a normal environment using the above-mentioned copying machine. The presence or absence of streaks of the charging roll pitch in the image was visually evaluated. The results are summarized in Table 2.
A: No streak defect.
○: Extremely slight streaks are generated.
Δ: Minor streaks are generated.
×: A streak that cannot be actually used is generated.

<Example 6>
A conductive elastic layer H was produced in the same manner as in Example 5 except that the cooling water temperature was changed to 25 ° C., a surface layer was formed in the same manner as in Example 5, and a conductive roll 8 was obtained. The results are summarized in Table 2.

<Example 7>
A conductive elastic body I was produced in the same manner as in Example 5 except that the cooling water temperature was changed to 60 ° C., a surface layer was formed in the same manner as in Example 5, and a conductive roll 9 was obtained. The results are summarized in Table 2.

<Example 8>
A conductive elastic layer J was produced in the same manner as in Example 5 except that the cooling water was not circulated and the vulcanization time was changed to 20 minutes. A roll 10 was obtained. The results are summarized in Table 2.

<Comparative Example 3>
A conductive elastic layer K was produced in the same manner as in Example 5 except that the cooling water temperature was changed to 5 ° C. and the vulcanization time was changed to 18 minutes. A roll 11 was obtained. The results are summarized in Table 2.

<Comparative example 4>
A conductive elastic layer L was produced in the same manner as in Example 5 except that the molding method of Example 5 was cast using a normal mold without using an electromagnetic induction coil or cooling water. A surface layer was formed in the same manner as in Example 1 to obtain a conductive roll 12. The results are summarized in Table 2.

  As an application example of the present invention, there is application to an image forming apparatus such as a copying machine or a printer using an electrophotographic system.

  10, 30 conductive elastic layer, 12 conductive elastic material, 20 core metal, 20a layer forming part, 20b shaft part, 40 heating device, 42, 68 electromagnetic induction coil, 50, 60 mold, 52, 62 support part , 54, 64 space, 56, 66 Mold housing part, 58, 72 Cooling water circulation passage, 70 Cooling device, 100, 110 Conductive roll, 200 Image forming device, 300, 310 Manufacturing device, 400 Housing, 401a, 401b , 401c, 401d Electrophotographic photosensitive member, 402a to 402d charging roll, 403 exposure device, 404a to 404d developing device, 405a to 405d toner cartridge, 406 driving roll, 407 stretching roll, 408 back roll, 409 intermediate transfer belt, 410a ˜410d primary transfer roll, 411 transferred medium container, 12 transport roll, 413 secondary transfer roll, 414 fixing roll, 415 a to 415 d cleaning blade 416 a cleaning blade.

Claims (2)

An apparatus for manufacturing a conductive roll comprising a mold having a space for forming an elastic layer, a support portion for supporting a core metal that is passed in the longitudinal direction of the space, and a filling port for filling the space with an elastic material. Because
A cooling device is provided in the mold,
Furthermore, the heating apparatus with which the core metal protruded from the said support part is mounted | worn is provided, The manufacturing apparatus of the electroconductive roll characterized by the above-mentioned. An apparatus for manufacturing a conductive roll comprising a mold having a space for forming an elastic layer, a support portion for supporting a core metal that is passed in the longitudinal direction of the space, and a filling port for filling the space with an elastic material. Because
A heating device is provided in the mold,
Furthermore, the manufacturing apparatus of the electroconductive roll characterized by the above-mentioned. The cooling device with which the metal core protruded from the said support part is mounted | worn is provided.