JP5755078B2 - Manufacturing method of regenerative elastic roller - Google Patents

Description

  The present invention relates to a method for manufacturing a regenerative elastic roller.

  In the electrophotographic image forming apparatus, elastic rollers such as a developing roller, a charging roller, a transfer roller, a fixing roller, and a cleaning roller are used. With such use, toner, external additives, and the like adhere to the surface of such an elastic roller and gradually accumulate. In the electrophotographic image forming apparatus, the surfaces of these elastic rollers are usually cleaned by various cleaning means. However, the toner, external additives, and the like that could not be removed by these cleaning means may adhere to and accumulate on the surface of the elastic roller due to long-term use.

  By the way, in recent years, from the viewpoint of reducing the environmental load, there is an increasing need for technology development that enables reuse of an elastic roller having an external additive or the like deposited on its surface as a result of its use.

  In Patent Document 1, for an elastic roller having filming on the surface due to fixing of a developer or the like, the surface of the elastic roller is pressed to cause cracking in the filming, and then filming is performed using an adhesive roller. A method of manufacturing a regenerative elastic roller having a removing step is disclosed.

Japanese Patent No. 4144899

  According to the method disclosed in Patent Document 1, filming on the surface of the elastic roller can be effectively removed. However, the present inventors have recognized that it is necessary to develop a method capable of removing the external additive more efficiently for the elastic roller having a large amount of the external additive attached thereto.

  Accordingly, an object of the present invention is to provide a method for producing a regenerative elastic roller that efficiently removes external additives attached to the surface of the elastic roller and contributes to good image formation.

A method for producing a regenerative elastic roller according to the present invention is a method for producing a regenerative elastic roller having a step of removing an external additive derived from toner adhering to the surface of the elastic roller, the step comprising:
(1) The elastic roller and the pressing member are rubbed against each other at the nip portion between the elastic roller having the external additive attached to the surface and the pressing member disposed to face the elastic roller. By supplying porous resin particles charged to a normal charging polarity opposite to the normal charging polarity of the external additive, and rubbing the porous resin particles against the surface of the elastic roller at the nip portion, Charging the porous resin particles to a normal charge polarity opposite to that of the external additive, and incorporating the external additive into the pores of the porous resin particles;
(2) The surface potential of the removal member with respect to the surface potential of the elastic roller is between the surface of the removal member disposed opposite to the elastic roller and the surface of the elastic roller. A step of applying a potential difference that is opposite to the polarity and transferring the porous resin particles incorporating the external additive from the surface of the elastic roller to the surface of the removing member. .

  According to the present invention, it is possible to more efficiently manufacture a regenerative elastic roller that contributes to the formation of a high-quality electrophotographic image.

It is a schematic sectional drawing which shows an example of the reproduction | regeneration elastic roller obtained from this invention, (a) It is parallel to a longitudinal direction and (b) is perpendicular | vertical to a longitudinal direction. It is a schematic block diagram which shows two examples of the external additive removal apparatus which can be used for this invention. It is a schematic block diagram which shows an example of the electric current value measuring device of the reproduction | regeneration elastic roller obtained from this invention. It is a schematic block diagram which shows an example of the electrophotographic image forming apparatus using the reproduction | regeneration elastic roller obtained from this invention. It is a schematic block diagram which shows an example of the electrophotographic process cartridge using the reproduction | regeneration elastic roller obtained from this invention.

  First, the present inventors supply porous resin particles to the nip portion between the elastic roller and the pressing member having an external additive attached to the surface, rotate the elastic roller, and the porous resin particles in the nip portion. It was found that the external additive can be removed by pressing and rubbing the particles against the surface of the elastic roller.

The present inventors infer the reason as follows.
That is, the present inventors deformed the porous resin particles supplied to the nip portion between the elastic roller and the pressing member by being pressed and rubbed in the nip portion, and removed the external additive attached to the elastic roller surface. I think that it took in the hole effectively.

  However, as the elastic roller is repeatedly regenerated using the porous resin particles, the cleaning performance may be deteriorated. This is thought to be because the pores of the porous resin particles were filled by incorporating the external additive, and the external additive removal performance of the porous resin particles was lowered. Therefore, the present inventors made further studies and obtained the following knowledge.

  In the following description, the case where the toner-derived external additive is negatively charged will be described as an example. When the external additive is positively charged, positive and negative are reversed in the following description. The charging polarity of the external additive, the porous resin particles, and the porous resin particles incorporating the external additive means a relative charging polarity with respect to the elastic roller surface.

  The external additive means various inorganic and organic additives added for the purpose of imparting various properties such as chargeability and fluidity to the toner. Examples of the external additive include silica, titanium oxide, tin oxide, zinc oxide, strontium titanate, aluminum oxide, vinylidene fluoride, and zinc stearate. Among these, the external additive is preferably silica or titanium oxide because the effect of imparting chargeability and fluidity to the toner is great. These external additives can be used in combination.

  The charge polarity of the external additive can be selected depending on the surface treatment method. For example, by treating the surface of silica or titanium oxide with hexamethyldisilazane or γ-mercaptopropyltrimethoxysilane, External additives can be obtained. Further, for example, by treating the surface of silica or titanium oxide with amino-modified silicone oil, a positively chargeable external additive can be obtained.

  In the present invention, the normal charge polarity (negative) of the external additive with respect to the elastic roller is opposite to that of the elastic roller at the nip portion between the elastic roller having the external additive attached to the surface and the pressing member disposed opposite to the elastic roller. Porous resin particles that are positively charged are used. Further, means (removal member) for applying a potential difference between the normal charge polarity (positive) and the same polarity (positive) of the porous resin particles on the elastic roller surface is used. As a result, a reduction in cleaning performance can be prevented, and stable cleaning performance can be obtained. This will be described in detail below.

  First, when the elastic roller rotates, the porous resin particles rubbed at the nip portion electrostatically adhere to the surface of the elastic roller after passing through the nip portion and move in conjunction with the elastic roller. At this time, the porous resin particles have a normal charging polarity (positive) opposite to that of the external additive by pressing and friction at the nip portion of the elastic roller and the pressing member, and by taking in the external additive, The charging property gradually changes, and finally the normal charging polarity changes to the same polarity (negative) as the normal charging polarity of the external additive. For this reason, the porous resin particles electrostatically attached to the surface of the elastic roller are usually obtained by sufficiently taking in the externally charged particles and the particles that are charged to the normal charging polarity (positive) of the normal porous resin particles. Is considered to be in a state in which particles charged to the opposite normal charging polarity (negative) are mixed. By disposing a removing member that imparts a potential difference of the same polarity (positive) as the normal charging polarity of normal porous resin particles on the surface of the elastic roller in this state, a normal charging polarity (negative) that is opposite to normal is set. ) Is removed by the electric field.

  That is, since the porous resin particles having a reduced cleaning performance can be removed by incorporating the external additive, stable external additive removal performance can be obtained.

Furthermore, the present inventors have found that the external additive removal treatment becomes more effective because the elastic roller is conductive. In the case of a conductive elastic roller, it is possible to easily prevent electric charges from remaining on the surface of the elastic roller when the charged porous resin particles are removed from the surface of the elastic roller. The presence of this residual charge (hereinafter referred to as counter charge) can easily prevent the potential difference with respect to the elastic roller from becoming unstable. That is, since the elastic roller is electrically conductive, this counter charge is particularly suppressed, and the potential difference from the removal member can be kept constant easily, so that the removal action of the porous resin particles incorporating the external additive is further increased. It is thought to increase. In the present invention, the term “conductive” means that the volume resistivity when 50 V is applied is 1 × 10 ¹⁰ Ω · cm or less.

  Furthermore, the present inventors have found that by producing a regenerated elastic roller by the production method of the present invention, it is possible to remove the external additive to form a good image and promote effective utilization of resources. .

  Furthermore, the present inventors can mount a regenerative elastic roller obtained from the present invention in an electrophotographic process cartridge, thereby removing external additives and forming a good image, thereby promoting effective use of resources. I found out that I can do it.

  Furthermore, the present inventors can mount a regenerative elastic roller obtained from the present invention in an electrophotographic image forming apparatus to remove external additives and form a good image, thereby promoting effective use of resources. I found out that I can.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

<Regenerative elastic roller>
The regenerative elastic roller according to the present invention can be used as an elastic roller for an electrophotographic apparatus used in an image forming apparatus using an electrophotographic method, and specifically includes a developing roller, a charging roller, a transfer roller, and a fixing roller. It can be used for cleaning rollers and the like.

  An example of the regenerative elastic roller according to the present invention is shown in the schematic view of FIG. The regenerative elastic roller 10 is obtained by removing the external additive from the elastic roller with the external additive attached to the surface by image formation or the like, so that the elastic roller itself, that is, the surface has no external additive attached thereto. This elastic roller can have the same configuration as the regenerative elastic roller. Hereinafter, the configuration of the elastic roller itself will be described by taking the regenerative elastic roller as an example.

  (A) in the figure represents a cross section parallel to the longitudinal direction of the regenerative elastic roller, and (b) represents a cross section perpendicular to the longitudinal direction. In FIG. 1, the regenerative elastic roller 10 has an elastic layer 12 around a cylindrical conductive shaft core 11 and a surface layer 13 around the elastic layer 12. Two or more surface layers 13 may be formed. The regenerative elastic roller obtained from the present invention can also be composed of the conductive shaft core 11 and the elastic layer 12.

  Hereinafter, the regenerative elastic roller 10 of FIG. 1 will be described in detail.

[Conductive shaft core]
The material of the conductive shaft core 11 is not particularly limited as long as it is conductive, and can be appropriately selected from carbon steel, alloy steel, cast iron, and conductive resin.

[Elastic layer]
The elastic layer 12 is provided for imparting the elasticity required for the regenerative elastic roller to the regenerative elastic roller 10 in an apparatus using the regenerative elastic roller. As a specific configuration, either a solid body or a foam may be used. The elastic layer 12 may be a single layer or may be composed of a plurality of layers. For example, since the developing roller and the charging roller are always in pressure contact with the photosensitive drum and the toner, the elastic layer 12 having the characteristics of low hardness and low compression strain is used to reduce the mutual damage between these members. Is provided.

  Examples of the material of the elastic layer 12 include natural rubber, isoprene rubber, styrene rubber, butyl rubber, butadiene rubber, fluorine rubber, urethane rubber, and silicone rubber. These can be used alone or in combination of two or more.

  The elastic layer 12 contains a cross-linking agent, a catalyst, a dispersion accelerator, etc. as a conductive agent, a non-conductive filler, and other various additive components required for molding according to the function desired for the regenerative elastic roller 10. It may be contained.

  As the conductive agent contained in the elastic layer 12, it is possible to use various conductive metals or alloys, conductive metal oxides, electronic conductive agents such as fine powders of insulating materials coated with these, and ionic conductive agents. it can. These conductive agents can be used alone or in combination of two or more in the form of powder or fiber. Of these, carbon black, which is an electronic conductive agent, is preferable because it is easy to control conductivity and is economical.

By containing such a conductive agent, for example, a volume resistivity of 1 × 10 ⁴ to 1 × 10 ¹⁰ Ω · cm can be imparted to the elastic layer 12. A developing roller having a volume resistivity of the elastic layer 12 in this range can easily have uniform charge controllability with respect to the toner. The volume resistivity in the elastic layer 12 of the developing roller is more preferably 1 × 10 ⁴ to 1 × 10 ⁹ Ω · cm.

  Examples of the non-conductive filler that may be contained in the elastic layer 12 include the following. Diatomaceous earth, quartz powder, dry silica, wet silica, titanium oxide, zinc oxide, aluminosilicate, calcium carbonate, zirconium silicate, aluminum silicate, talc, alumina, iron oxide and the like.

  The elastic layer 12 imparts the desired elasticity to the regenerative elastic roller 10, and as its hardness, for example, the Asker C hardness is preferably 10 degrees or more and 80 degrees or less. If the Asker C hardness of the elastic layer 12 is 10 degrees or more, the oil component from the rubber material constituting the elastic layer 12 can be easily prevented from leaching, and contamination of the photosensitive drum can be easily suppressed. Further, if the Asker C hardness of the elastic layer 12 is 80 degrees or less, the deterioration of the toner can be easily suppressed and the deterioration of the image quality of the output image can be easily suppressed.

  Here, the Asker C hardness is defined by a measured value measured by an Asker rubber hardness meter (manufactured by Kobunshi Keiki Co., Ltd.) using a test piece separately prepared according to the standard standard Asker C type SRIS (Japan Rubber Association Standard) 0101. be able to.

  For example, in the case of a developing roller, the thickness of the elastic layer 12 may be 0.5 mm to 50 mm, and more preferably 1 mm to 10 mm.

  As the molding method of the elastic layer 12, for example, it is molded on the shaft core by heating and curing at an appropriate temperature and time by various molding methods such as extrusion molding, press molding, injection molding, liquid injection molding, and cast molding. The method of doing can be mentioned. The elastic layer 12 can be accurately formed around the shaft core body by a method in which an uncured elastic layer material is injected into a cylindrical mold having the shaft core body and heated and cured.

[Surface layer]
The regenerative elastic roller 10 may be one in which a resin layer as one or more surface layers is provided on the elastic layer 12 in order to easily impart the desired functionality. Further, in order to easily impart the desired functionality, a resin layer may be provided under the elastic layer, that is, between the elastic layer 12 and the conductive shaft core 11. Further, the resin layer may be a surface layer that protects the surface of the regenerative elastic roller 10, imparts wear resistance, and suppresses toner adhesion. As the binder resin of the surface layer 13 which is such a resin layer, for example, a nitrogen-containing resin such as a urethane resin or an acrylic urethane resin is preferable. The developing roller having the resin surface layer 13 can easily and stably charge the toner, has a low tack property, easily suppresses adhesion of the toner, and facilitates peeling of the toner. it can.

The urethane resin used here can be obtained from an isocyanate compound and a polyol.
When the surface layer 13 containing a urethane resin as a binder resin is provided on the elastic layer 12, the elastic layer 12 is irradiated with ultraviolet rays, and then a coating film of a coating liquid containing an uncured surface layer forming resin material is applied to the elastic layer. It is preferable to provide it above. By irradiating with ultraviolet rays, a hydroxyl group that forms a chemical bond with the isocyanate constituting the urethane resin is generated in the elastic layer 12 to form a strong bond between the surface layer 13 containing the urethane resin and the elastic layer 12. it can.

  As a urethane resin, a resin obtained by mixing and reacting at least a polyurethane prepolymer having a hydroxyl group at a terminal and a blocked isocyanate at an NCO equivalent (value of [NCO] / [OH]) of 1.1 to 1.5. It is preferable to use it as a main component. When the NCO equivalent is 1.1 or more, the adhesiveness with the elastic layer 12 can be easily obtained, and damage to the surface layer 13 due to repeated regeneration processing can be easily suppressed. Moreover, if the NCO equivalent is 1.5 or less, excessive increase in hardness of the surface layer 13 can be easily suppressed. As a result, damage to the porous resin particles at the nip with the pressing member is suppressed, and the external additive uptake effect of the porous resin particles is further stabilized.

  The surface layer 13 may contain a conductive agent in order to adjust the electric resistance of the regenerative elastic roller 10. Specific examples of the conductive agent contained include those similar to the conductive agent used for the elastic layer 12.

  As a standard of the thickness of the surface layer 13, it is preferably 1 μm or more and 500 μm or less, and particularly preferably 1 μm or more and 50 μm or less. As a method for forming the surface layer 13, for example, a coating liquid containing an uncured resin material for forming a surface layer is prepared and formed by a coating method such as a dipping method, a roll coating method, a ring coating method, or a spray method. A method can be mentioned.

  The surface roughness of the regenerative elastic roller 10 is not particularly limited, but it is appropriately adjusted and used for the purpose of securing a toner conveying force and suppressing ghosts and shading unevenness with sufficient image density to obtain a high quality image. be able to.

  As a means for controlling the surface roughness, it is effective to make the surface layer 13 contain particles having a desired particle diameter (surface roughness control particles). Moreover, it is also possible to form a desired surface roughness by subjecting the roller surface to appropriate polishing treatment before and after the formation of the surface layer 13. In that case, when a plurality of elastic layers 12 are formed, polishing treatment may be performed after the plurality of layers are formed. When the elastic layer 12 and the surface layer 13 are formed, the surface layer 13 may be formed after the elastic layer 12 is formed and then the polishing process may be performed, or the polishing process may be performed after the surface layer 13 is formed. .

  As the surface roughness control particles to be contained in the surface layer 13, for example, metal particles and resin particles having a number average particle size of 0.1 μm to 30.0 μm can be used. The number average particle diameter of the surface roughness control particles can be determined from the arithmetic average value of the maximum diameters selected and measured at random from 200 images taken with a scanning electron microscope. Among these, resin particles that are highly flexible, have a relatively small specific gravity, and easily obtain the stability of the paint are more preferable. Examples of the resin particles include polyurethane particles and acrylic particles. When the surface layer 13 is formed in a plurality of layers, the surface roughness control particles may be contained in all of the plurality of layers, or the surface roughness control particles may be contained in at least one of the plurality of layers.

<External additive removal device>
FIG. 2 is a schematic configuration diagram showing two examples of an external additive removing apparatus that can be used in the method for producing a regenerated elastic roller of the present invention. An external additive removing device 20 shown in FIG. 2A includes a container 21, porous resin particles 22, a pressing member 23, and a removing member 24. Further, the external additive removing apparatus shown in FIG. 2B, which is a more preferable form, includes a container 21, porous resin particles 22, a pressing member 23, a removing member 24, a sponge roller 31, and a cleaning blade 32. Further, the removing member 24 can include a power source (V) 25. By using these apparatuses in the production method of the present invention, the external additive of the charging roller 1 having the external additive attached to the surface can be removed as porous resin particles incorporating the external additive.

  The method for producing a regenerative elastic roller according to the present invention includes a step of removing an external additive adhering to the surface of the elastic roller 1, and the step of removing the external additive includes the following steps (1) and (2). ) And can also consist of step (1) and step (2). The steps (1) and (2) will be described in detail below. Hereinafter, the case where the normal charging polarity of the external additive is negative will be described as an example.

[Step (1)]
In the step (1), first, the elastic roller 1 and the pressing member 23 disposed opposite to the elastic roller 1 are rubbed between the elastic roller and the pressing member at the nip portion of the elastic roller 1 so as to be opposite to the external additive. The porous resin particles 22 charged to the normal charging polarity (positive) are supplied. At the nip portion, the porous resin particles 22 are rubbed against the surface of the elastic roller to which the external additive derived from the toner adheres, thereby causing the porous resin particles to have a normal charging polarity (positive) opposite to that of the external additive. While being charged, the external additive attached to the elastic roller 1 is taken into the pores of the porous resin particles.
As a result, the frictional charge polarity (negative) opposite to the charge polarity (positive) of the porous resin particles before incorporating the external additive, that is, the charge polarity changed to the same polarity (negative) as the external additive, Porous resin particles incorporating the additive can be obtained. The normal charging polarity of the external additive, the porous resin particles, and the porous resin particles incorporating the external additive can be specified by a Q / M measurement method described later. If the charge amount measured by this method is positive (+), the elastic roller is positively charged, and if it is negative (−), the elastic roller is negatively charged.

  In the apparatus shown in FIG. 2A, the container 21 is filled with porous resin particles 22, and a part of the container 21 is opened so that the porous resin particles 22 can be supplied to the nip portion between the elastic roller 1 and the pressing member 23. Yes. The opening may be provided with a seal member (not shown) for preventing leakage of the porous resin particles 22 when the elastic roller 1 is detached.

  Further, in order to obtain a stable cleaning performance, the container 21 is supplied with the porous resin particles 22 to the surface of the elastic roller 1, and the porous resin particles 22 remaining on the surface of the elastic roller 1 are collected in the container 21. It is preferable that a member is provided. As this member, for example, a foamed urethane sponge roller 31 having a shaft core as shown in FIG. 2B can be cited. By rotating the roller 31 in contact with the elastic roller 1, The porous resin particles 22 can be supplied to and recovered from the surface of the elastic roller 1.

  The porous resin particles used in the present invention are externally bonded by friction at the nip portion of the elastic roller 1 and the pressing member 23 from the viewpoint of removing the porous resin particles incorporating the external additive in the step (2) described later. It is required to select a material that is charged with a normal charging polarity opposite to that of the additive.

  As porous resin particles, various materials and physical properties of resin particles can be used as long as they have the above properties and are porous. Generally, a molecule containing a nitrogen atom is easily positively charged and therefore can be used to remove a negatively charged external additive. A molecule containing a halogen atom is easily negatively charged and thus a positively charged external additive. It can be used for removal. Accordingly, examples of the porous resin particles that can be used for removing the negatively charged external additive include porous acrylic resin particles and porous polyamide resin particles. Examples of the porous resin particles that can be used for removing the positively charged external additive include porous polyvinylidene chloride resin particles.

  As an example of a method for producing porous acrylic resin particles, a polymerizable acrylic monomer such as (meth) acrylic acid, (meth) acrylate, and (meth) acrylic acid ester, and a crosslinking agent are mixed with water and an organic solvent. A method of obtaining porous acrylic resin particles by suspension polymerization in a liquid is mentioned.

  In addition, as an example of a method for producing porous polyamide resin particles, there is a method of obtaining porous polyamide resin particles by preparing a mixed liquid of a polyamide resin and its good solvent, poor solvent, and water, and then allowing it to stand still. . A method for synthesizing porous polyamide resin particles is disclosed in, for example, JP-A-2002-080629.

  An example of a method for producing porous polyvinylidene chloride resin particles includes a method of obtaining porous polyvinylidene chloride by suspension polymerization of a polymerizable monomer in a mixed liquid of water and an organic solvent. The synthesis of porous polyvinylidene chloride resin particles is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-091517.

The porous resin particles have a number average particle diameter of 5 μm or more and 100 μm or less, a specific surface area of 5 m ² / g or more and 100 m ² / g or less, and a pore diameter that is one times the average primary particle diameter of the external additive. It is preferable that it is 100 times or less. Here, the number average particle diameter of the porous resin particles can be obtained from the arithmetic average value of the maximum diameters selected and measured at random from 200 images taken with a scanning electron microscope. The specific surface area can be measured according to the specific surface area measurement method of JIS Z8830. The pore diameter of the porous resin particles can be specified by mercury porosimetry, and the primary particle diameter of the external additive can be specified in the same manner as described above from imaging with a transmission electron microscope.

  When the number average particle diameter is 5 μm or more, it is possible to easily prevent the porous resin particles from adhering to the elastic roller 1 due to the increased adhesion of the porous resin particles. If the number average particle diameter is 100 μm or less, the electrostatic adhesion action is easily prevented from being weakened, the porous resin particles are retained on the elastic roller surface, and the potential difference due to the change in the charging polarity in the step (2) described later. It becomes easy to remove porous resin particles using.

If the specific surface area is 5 m ² / g or more, a sufficient cleaning effect can be easily obtained by incorporating an external additive into the hole. If it is 100 m < ² > / g or less, the fall of the cleaning performance by the porous resin particle breaking and the contamination of the elastic roller surface can be prevented easily.
Moreover, if the pore diameter of the porous resin particles is 1 to 100 times the particle diameter of the external additive, the external additive can be effectively taken into the pores.

  The pressing member 23 is disposed so that the elastic roller 1 can be elastically brought into contact with the pressing member. As the pressing member 23, a pressing blade or a pressing roller is preferably used.

  As a material of the pressing member 23, it is preferable that the pressing member 23 has a durable strength without damaging the surface of the elastic roller 1 against contact with the rotating elastic roller 1. In addition, from the viewpoint of selective removal of porous resin particles in the step (2) described later, a friction charge series suitable for charging external additives and porous resin particles to a desired polarity is selected. Is preferred.

  As the pressing blade, polyisoprene, butadiene-styrene copolymer, polybutadiene, isobutylene-isoprene copolymer, butadiene-acrylonitrile copolymer, ethylene-propylene copolymer, chlorosulfonated polyethylene, acrylate copolymer, Single layer of rubber elastic member such as polyurethane, organic polysiloxane, perfluoropropene, vinylidene fluoride copolymer, metal elastic member such as Ni, SUS (stainless steel), Al, phosphor bronze, etc., or support member thereof The support member is preferably composed of a composite layer in which a resin such as polyurethane, polyamide, polyimide, polyamideimide, polyetherimide, polyetheretherketone, polyphenylene sulfide, or liquid crystal polymer is laminated. Among these, materials made of a material such as polyurethane are preferably used so that the triboelectric series is intermediate between the external additive and the porous resin particles.

  Moreover, as a press roller, the structure similar to what was illustrated as the said reproduction | regeneration elastic roller 10 can be mentioned. Further, the pressure roller may be rotated by using a driving unit in consideration of charge imparting property, durability, and the like.

  The pressure for pressing the pressing member 23 to load the elastic roller 1 is preferably 10 N / m or more and 500 N / m or less, more preferably 20 N / m or more and 300 N / m or less in terms of drawing pressure. When the drawing pressure applied to the elastic roller 1 is 10 N / m or more, the external additive on the surface of the elastic roller 1 can be efficiently taken into the pores of the porous resin particles. It is possible to easily suppress damage to the elastic roller 1 at the time. Here, the drawing pressure can be measured by the following method. A pulling SUS plate having a thickness of 30 μm is sandwiched between two SUS plates having a thickness of 30 μm and inserted into a contact portion between the pressing member 23 and the elastic roller 1. Next, the pulling SUS plate is pulled and the force when it is pulled out at a speed of 0.5 cm / sec is measured to obtain a linear pressure equivalent value converted into a force per 1 m width of the SUS plate. The pulling force is a value measured with a digital force gauge (trade name: DS2, manufactured by Imada Co., Ltd.).

[Step (2)]
In the step (2), the porous resin particles whose normal charging polarity has been changed by incorporating the external additive (porous resin particles incorporating the external additive) are removed from the elastic roller surface by applying an electric field. Specifically, the surface potential of the removing member with respect to the surface potential of the elastic roller 1 is opposite to the normal charging polarity of the external additive between the surface of the elastic roller 1 and the surface of the removing member installed facing the elastic roller 1. A potential difference that is polar is applied. By this electric field, the porous resin particles incorporating the external additive are transferred from the surface of the elastic roller to the surface of the removing member and removed from the surface of the elastic roller.

  As described above, the porous resin particles that have taken in the external additive by pressing and friction at the nip portion between the elastic roller 1 and the pressing member 23 in the step (1) have a cleaning capability because the hole portion is filled with the external additive. May decrease. However, stable cleaning performance can be obtained by removing the porous resin particles incorporating the external additive in the step (2).

In the external additive removing apparatus shown in FIG. 2B, the elastic roller 1 and the sponge roller 31 are rotated counterclockwise (a and b directions), and the removing member 24 is rotated clockwise (c direction). It is rotating. Further, the removing member 24 is disposed downstream of the nip portion between the elastic roller 1 and the pressing member 23 so as to face the elastic roller 1. Further, the removing member 24 is provided with a power source (V) 25, and the potential difference between the elastic roller 1 and the removing member can be arbitrarily adjusted.
Further, a power source (not shown) may be installed on the shaft core body of the elastic roller 1 in order to easily control the potential difference with the removing member 24. The removing member 24 can be appropriately used from a material capable of imparting a desired charge to the surface of the removing member 24, and is not particularly limited. However, it is more preferably conductive for imparting a stable potential difference.

  Moreover, in order to prevent the porous resin particles having taken in the external additive on the surface of the removing member 24 from being deposited, the shape of the removing member 24 is preferably a cylinder or an endless belt. Furthermore, the removing member is preferably provided with a cleaning mechanism such as a cleaning blade 32 for removing the porous resin particles incorporating the external additive as shown in FIG. Thereby, accumulation of porous resin particles on the removal member surface can be easily prevented.

  Further, the potential difference between the removing member 24 and the elastic roller 1 and the positional relationship with each other should be adjusted as appropriate in consideration of the chargeability of the porous resin particles incorporating the external additive and the required cleaning ability. Can do.

Next, an example of the operation of the external additive removing device will be described.
First, the elastic roller 1 to which an external additive is attached is disposed so as to face the pressing member 23 so as to contact the pressing member 23 with a desired pressure. Next, the removing member 24 that gives a desired potential difference to the elastic roller 1 is disposed opposite to the elastic roller 1 at a desired position downstream of the pressing member 23 in the rotation direction of the elastic roller 1. The removal member 24 is disposed in contact with the elastic roller 1, for example, in consideration of the chargeability of the porous resin particles and external additives and the required cleaning performance.

Thereafter, the elastic roller 1 is rotated by, for example, driving means to start processing. Rotation speed of the elastic roller 1, in consideration of the charging of the external additive removal efficiency and the porous resin particle, for example, be set in the range of 5min ^-1 (rpm) 800min ^-1 of (rpm).
Further, when the removal member 24 is rotated, it may be set so that a circumferential speed difference is generated with respect to the elastic roller 1. By adjusting the peripheral speed difference, it is possible to change the removal efficiency of the porous resin particles incorporating the external additive having changed charging polarity.

  In the present invention, step (2) may be performed after step (1), and step (1) and step (2) may be performed simultaneously and in parallel. By performing the steps (1) and (2) simultaneously, the external additive can be efficiently removed.

<Current value measuring device>
The removal of the external additive attached to the elastic roller means that, for example, a voltage is applied to each of the elastic roller before and after the external additive is attached by image formation and the regenerative elastic roller 10 by the following method. It can be confirmed by measuring the current value of and comparing the measured values. The current value of each elastic roller can be measured using, for example, a current value measuring device 40 shown in FIG.
Specifically, a load of 500 g is applied to the shaft core exposed portions at both ends of the regenerative elastic roller 10, and the outer peripheral surface of the regenerative elastic roller 10 is brought into contact with the SUS cylindrical electrode 41 having a diameter of 40 mm. In this state, the cylindrical electrode is rotated, and the regenerative elastic roller 10 is rotated by rotation. When the rotation is stabilized, a voltage is applied to the shaft core body from the DC power source 42, and a voltage of 50V is applied between the cylindrical electrode. The environment at this time is 20 ° C. and 50% RH (relative humidity). The current value at that time is measured by an ammeter (A) 43 for one revolution of the regenerative elastic roller, and the average value is obtained as the current value of the regenerative elastic roller 10. The volume resistivity ρ is the measured current value I, internal resistance R, applied voltage V, nip area S between the SUS cylindrical electrode 41 and the regenerative elastic roller 10, the elastic layer and the surface layer of the regenerative elastic roller 10. It can be determined from the total layer thickness t by the following formula.
ρ = (V / IR) × S / t
<Electrophotographic image forming apparatus and electrophotographic process cartridge>
An electrophotographic image forming apparatus and an electrophotographic process cartridge using a regenerative elastic roller obtained from the present invention include a photoconductor on which an electrostatic latent image is formed, a charging member for charging the photoconductor, and a static on the photoconductor. And a developing member for developing the electrostatic latent image. Further, the apparatus and the process cartridge can use the regenerative elastic roller obtained from the present invention as at least one of the charging member and the developing member. The electrophotographic process cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus.

  An example of an electrophotographic image forming apparatus in which the regenerative elastic roller 10 obtained from the present invention is mounted as a developing roller will be described below with reference to FIG. The electrophotographic image forming apparatus 100 shown in FIG. 4 is provided with image forming units I, II, III, and IV provided for each color toner of yellow toner, magenta toner, cyan toner, and black toner. Each image forming unit is provided with a photoreceptor 101 as an electrostatic latent image carrier that rotates in the direction of the arrow (counterclockwise on the paper surface). Around each photoconductor, a charging device 107 for uniformly charging the photoconductor 101, an exposure unit for irradiating the uniformly charged photoconductor with a laser beam 106 to form an electrostatic latent image, A developing device 105 is provided that supplies toner to the photosensitive member on which the electrostatic latent image is formed to develop the electrostatic latent image.

  On the other hand, a transfer conveyance belt 116 that conveys a recording material 118 such as paper supplied by a paper supply roller 119 is provided to be suspended from a driving roller 112, a driven roller 117, and a tension roller 115. The transfer / conveying belt 116 is charged with the charge of the attracting bias power source 121 via the attracting roller 120, and the recording material 118 is electrostatically attached to the surface and transported.

  A transfer bias power supply 114 is provided for applying a charge for transferring the toner image on the photosensitive member of each image forming unit to the recording material 118 conveyed by the transfer conveyance belt 116. The transfer bias is applied via a transfer roller 113 disposed on the back surface of the transfer conveyance belt 116. The toner images of the respective colors formed in the image forming units are sequentially superimposed and transferred onto a recording material 118 conveyed by a transfer conveying belt 116 that is moved in synchronization with the image forming unit. .

  Further, in the color electrophotographic image forming apparatus, a fixing device 111 for fixing the toner image superimposed and transferred onto the recording material by heating or the like, and a conveying device (not shown) for discharging the image-formed recording material 118 to the outside of the apparatus. Is provided.

  On the other hand, each image forming unit is provided with a cleaning device 108 having a cleaning blade for removing residual toner remaining without being transferred onto each photoconductor and cleaning the surface. In addition, a waste toner container (not shown) that stores toner scraped off from the photoreceptor is provided. The cleaned photoconductor is set in an image-formable state and stands by.

The developing device 105 provided in each of the image forming units is provided with a toner container 103 containing non-magnetic toner as a one-component toner, and a toner container that closes the opening of the toner container. A regenerative elastic roller 10 obtained from the present invention, which is a developing roller, is provided so as to face the surface.
In the toner container, the toner is supplied to the developing roller, and at the same time, the toner supply roller 102 for scraping the toner remaining on the developing roller after development and the toner on the developing roller are formed in a thin layer. In addition, a toner regulating blade 104 (for example, manufactured by SUS304) that is frictionally charged is provided. These are arranged in contact with the developing roller.
A toner regulating blade bias power source 109 is connected to the toner regulating blade 104, a developing roller bias power source 110 is connected to the developing roller, and a voltage is applied to each of the toner regulating blade 104 and the developing roller during image formation.

Next, an example of an electrophotographic process cartridge in which the regenerative elastic roller 10 obtained from the present invention is mounted as a developing roller will be described with reference to FIG. A process cartridge 150 for an electrophotographic image forming apparatus shown in FIG. 5 includes a developing device 105, a photosensitive member 101, and a cleaning device 108, which are integrated and detachably provided on the main body of the electrophotographic image forming apparatus. It is done. An example of the developing device 105 is the same as that described in the electrophotographic image forming apparatus.
An electrophotographic process cartridge using a regenerative elastic roller obtained from the present invention is one in which a transfer member for transferring a toner image on a photosensitive member to a recording material is integrally provided with the above members in addition to the above configuration. May be.

Hereinafter, the present invention will be described in detail based on examples and comparative examples.
The following examples are examples of the best mode of the present invention, and the present invention is not limited to these examples.

<Particles used for external additive removal>
In Examples and Comparative Examples, the following particles were used for removing external additives.

[Porous resin particles 1]
For the porous resin particles 1, techpolymer MBP-8 (trade name) manufactured by Sekisui Plastics Co., Ltd., which is porous crosslinked polymethyl methacrylate (PMMA) resin particles, was used. Table 3 shows the physical properties of the porous resin particles 1.

  In addition, the charge amount Q / M per unit mass of the porous resin particles described in Table 3 was measured as follows. First, an external additive removing device, which will be described later, filled with the porous resin particles is mounted with an elastic roller, which will be described later, on which the external additive is not attached, and rotated at 500 rpm to frictionally charge the porous resin particles. I let you. Then, the porous resin particles present on the elastic roller after passing through the pressing blade are sucked and collected by the metal cylindrical tube and the cylindrical filter, and the charge amount of the porous resin particles stored in the condenser through the metal cylindrical tube at that time Q, The mass M of the sucked porous resin particles was measured. From these values, the charge amount Q / M (μC / g) per unit mass was calculated. This Q / M measurement method is hereinafter referred to as a suction method.

[Porous resin particles 2]
As the porous resin particles 2, porous polyamide resin particles obtained by the following synthesis method were used. Hereinafter, “part” means “part by mass”.
78.9 parts of methanol and 10.5 parts of water were mixed, and this mixture was mixed with 10.5 parts of m-cresol solution of polyamide 6 UBE nylon P1010 (trade name, manufactured by Ube Industries) having a concentration of 1.0% by mass. Was added while stirring with a magnetic stirrer. After stirring for 1 minute, the solution became homogeneous. The temperature was room temperature (23 ° C.). Stirring was stopped and the polymer was deposited 30 minutes after standing. Further, the mixture was allowed to stand for 24 hours to complete the precipitation. The polymer was then isolated by centrifugation. Next, hot air drying, vacuum drying and classification were performed to obtain porous resin particles 2. Table 3 shows the physical properties of the obtained porous resin particles 2.

[Porous resin particles 3]
As the porous resin particles 3, porous polyvinylidene chloride (PVDC) resin particles obtained by the following synthesis method were used.

  First, an oil phase made of the material shown in Table 1 and an aqueous phase made of the material shown in Table 2 were prepared.

  Subsequently, after mixing the oil phase and the aqueous phase, using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), mixing at 8000 rpm for 5 minutes, reacting at 80 ° C. for 6 hours, A polymerization liquid (hollow particle polymerization liquid) was obtained. The hollow particle polymerization liquid was preliminarily dehydrated and then dried with a stationary drier kept at 40 ° C. to obtain porous resin particles 3. Table 3 shows the physical properties of the obtained porous resin particles 3.

[Nonporous resin particles 1]
As the nonporous resin particles 1, Techpolymer MBX-8 (trade name) manufactured by Sekisui Plastics Co., Ltd., which is nonporous crosslinked polymethyl methacrylate resin particles, was used. Table 3 shows the physical properties of the nonporous resin particles 1.

[Porous inorganic particles 1]
As the porous inorganic particles 1, Sunsphere H-53 (trade name) manufactured by AGC S-Tech Co., Ltd., which is porous silica particles, was used. Table 3 shows the physical properties of the porous inorganic particles 1.

<Preparation of external additive>
[Hydrophobic silica 1]
Silica (trade name: AEROSIL 200CF, manufactured by Nippon Aerosil Co., Ltd.) was treated with 10 parts of hexamethyldisilazane to obtain hydrophobic silica 1. The primary particle size was 12 nm and the degree of hydrophobicity was 67. The primary particle size was measured with a transmission electron microscope (trade name: H-7500, manufactured by Hitachi, Ltd.).

Further, the degree of hydrophobicity of the treated inorganic fine powder (hydrophobic silica) was specified by the following methanol titration test. First, 0.2 g of inorganic fine powder was added to a container containing 50 ml of water, and methanol was titrated from the buret until the entire amount of the inorganic fine powder was wet while constantly stirring the solution in the container with a magnetic stirrer. . The end point of the titration is observed by suspending the total amount of inorganic fine powder in the liquid, and the degree of hydrophobicity is expressed as the percentage of methanol in the liquid mixture of methanol and water when the end point is reached.
Further, the measurement of the charge amount Q / M per unit mass of the obtained hydrophobic silica 1 was based on the measurement method of the charge amount Q / M per unit mass of the porous resin particles described above. The Q / M of the hydrophobic silica 1 was −72 μC / g.

[Hydrophobic silica 2]
Silica (trade name: AEROSIL 200CF, manufactured by Nippon Aerosil Co., Ltd.) was treated with 20 parts of amino-modified silicone oil to obtain hydrophobic silica 2. The primary particle size was 12 nm and the degree of hydrophobicity was 97. Further, Q / M was 67 μC / g.

[Hydrophobic titanium oxide 1]
Titanium oxide (trade name: P25, manufactured by Nippon Aerosil Co., Ltd.) was treated with 20 parts of γ-mercaptopropyltrimethoxysilane in toluene, filtered and dried to obtain hydrophobic titanium oxide 1. The primary particle size was 25 nm and the degree of hydrophobicity was 60. Further, Q / M was −47 μC / g.

<Production of elastic roller>
According to the following procedure, an elastic roller was produced in which the elastic layer 12 and the resin layer as the surface layer 13 were provided as a coating layer around the cylindrical conductive shaft core 11 one by one.

As the conductive shaft core body 11, a SUS304 core metal having a diameter of 6 mm and a length of 279 mm was used.
As a material for the elastic layer 12, liquid silicone rubber was prepared in the following manner. First, the materials shown in Table 4 below were mixed to form a liquid silicone rubber base material.

  To this base material, a platinum compound (manufactured by Toray Dow Corning, Pt concentration: 1% by mass) as a curing catalyst, and organohydrogenpolysiloxane (manufactured by Toray Dow Corning, weight average molecular weight 500) 3.0 The blended parts were mixed at a mass ratio of 1: 1 to obtain a liquid silicone rubber.

  The conductive shaft core 11 is placed in the center of a cylindrical mold having an inner diameter of 12 mm, and this liquid silicone rubber is injected into the cylindrical mold from the injection port, and is cured by heating at a temperature of 120 ° C. for 5 minutes. After cooling to (23 ° C.), the elastic layer integrated with the conductive shaft core 11 was removed. Further, the curing reaction was completed by heating at a temperature of 200 ° C. for 4 hours, and an elastic layer 12 mainly composed of silicone rubber having a thickness of 3 mm was provided on the outer peripheral surface of the conductive shaft core 11.

Then, the excimer process of the elastic layer 12 surface was performed on condition of the following.
The accumulated light amount becomes 120 mJ / cm ² by a thin tube excimer lamp (manufactured by Harrison Toshiba Lighting Co., Ltd.) capable of irradiating ultraviolet light having a wavelength of 172 nm while rotating the surface of the elastic layer 12 at 30 rpm around the conductive shaft core 11 as a rotation axis. Irradiation was performed as follows. The distance between the surface of the elastic layer 12 and the excimer lamp at the time of irradiation was 2 mm.

Next, the resin layer was coated as follows.
As the material for the resin layer, those shown in Table 5 below were used.

These materials were mixed stepwise in a methyl ethyl ketone solvent and reacted at 80 ° C. for 6 hours under a nitrogen atmosphere. The weight average molecular weight Mw = 10000, hydroxyl value 20.0 (mg · KOH / g), molecular weight dispersity. A bifunctional polyurethane prepolymer having Mw / Mn = 2.9 and Mz / Mw = 2.5 was obtained.
30.0 parts by mass of isocyanate (trade name: Coronate 2521, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100.0 parts by mass of this polyurethane prepolymer so that the NCO equivalent was 1.4. The NCO equivalent represents a ratio ([NCO] / [OH]) between the number of moles of isocyanate groups in the isocyanate compound and the number of moles of hydroxyl groups in the polyol component.

  Furthermore, 20.0 parts of carbon black (trade name: # 1000, pH 3.0, manufactured by Mitsubishi Chemical Corporation) was added. An organic solvent was added to the raw material mixture, and the solid content was appropriately adjusted in the range of 20% by mass to 30% by mass so that a film thickness of about 12 μm was obtained. Furthermore, 35.0 parts of urethane resin particles (trade name: C400 transparent, diameter 14 μm, manufactured by Negami Kogyo Co., Ltd.) were added and uniformly dispersed and mixed to obtain a raw material liquid for the resin layer.

  The conductive shaft core 11 having the elastic layer 12 formed thereon was immersed in the resin layer raw material liquid, and then pulled up and allowed to dry naturally. Next, a heat treatment was performed at a temperature of 140 ° C. for 60 minutes to cure the resin layer raw material liquid to obtain a resin layer having an average thickness of 12.0 μm as the surface layer 13. Furthermore, both ends of the coating layer were cut off and removed perpendicularly to the conductive shaft core 11, and the length of the coating layer was adjusted to 235 mm.

In this way, an elastic roller having an outer diameter of about 12 mm, a coating layer length of 235 mm, and a center line average roughness Ra of 1.7 μm according to JIS B 0601: 1994 surface roughness standards was produced.
Further, the current value of the elastic roller when left in an environment of a temperature of 23 ° C. and a humidity of 55% RH for 24 hours was measured with the apparatus shown in FIG. The initial current value at this time was 450 μA.

<Preparation of magenta colored particles>
[Preparation of polyester resin 1]
In an autoclave equipped with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device, the polyester monomers shown in Table 6 below were charged, under a nitrogen atmosphere, under normal pressure (101.3 kPa), The reaction was carried out at 220 ° C. for 20 hours, and the pressure was further reduced to 1.33 to 2.67 kPa (10 to 20 mmHg), followed by reaction for 1 hour.

  Thereafter, the temperature of the reaction product was lowered to 170 ° C., 0.10 parts of trimellitic anhydride was added, and the mixture was reacted at 170 ° C. for 1.0 hour to obtain polyester resin 1.

  [Preparation of low molecular weight polystyrene-acrylic resin 1]

  The materials shown in Table 7 above were charged, the reaction was carried out at 140 ° C. for 3.5 hours under a nitrogen atmosphere and normal pressure (101.3 kPa), and then the solvent was removed by holding at 180 ° C. for 2.0 hours. A low molecular weight polystyrene-acrylic resin was obtained. Mw = 4000, Mw / Mn = 2.53, and Tg (glass transition temperature) = 52 ° C.

[Dispersion medium]
To 1000 parts of ion-exchanged water in the reaction vessel, 14 parts of sodium phosphate and 4.5 parts of 10% by mass hydrochloric acid were added, and kept at 65 ° C. for 60 minutes while purging with N ₂ . Using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), while stirring at 12,000 rpm, 10 parts of ion-exchanged water was added together with an aqueous calcium chloride solution containing 7.8 parts of calcium chloride, and a dispersion stabilizer was added. An aqueous medium containing was prepared.

[Polymerizable monomer composition]
The materials shown in Table 8 below were added to an attritor dispersing machine (Mitsui Miike Chemical Co., Ltd.), and zirconia particles having a diameter of 1.7 mm were further added and dispersed at 220 rpm for 5 hours to obtain an intermediate composition. .

  Next, the materials shown in Table 9 below were added to the intermediate composition.

The above material was kept at 66 ° C. in a separate container, and uniformly dissolved and dispersed at 500 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). In this, 3.0 parts of a polymerization initiator t-hexyl peroxypivalate (manufactured by NOF Corporation, trade name “Perhexyl PV”, molecular weight: 202, 10 hour half-life temperature: 53.2 ° C.) is dissolved and polymerized. A functional monomer composition was prepared.
The polymerizable monomer composition was charged into the aqueous medium in the reaction vessel, stirred at 10,000 rpm for 5 minutes with a TK homomixer under N ₂ purge at 65 ° C., and granulated at pH 5.8. . Thereafter, while stirring with a paddle stirring blade, the temperature was raised to 65 ° C. for 6 hours and further to 90 ° C., and reacted for 6 hours.

  After completion of the polymerization reaction, the reaction vessel was cooled, and the dispersion stabilizer was dissolved while stirring for 2 hours in a state where pH was adjusted to 2 by adding 10% by mass hydrochloric acid. The emulsion was filtered under pressure and further washed with 2000 parts or more of ion exchange water. The obtained cake was returned to 1000 parts of ion-exchanged water again and washed again with stirring for 2 hours in a state where 10 mass% hydrochloric acid was added to adjust the pH to 1 or less. In the same manner as above, the emulsion was filtered under pressure, washed with 2000 parts or more of ion-exchanged water, sufficiently ventilated, dried under reduced pressure, and then classified with air to obtain magenta colored particles.

<Production of toner>
[Toner 1]
To 100 parts of the obtained magenta colored particles, 3.0 parts of hydrophobic silica 1 as an external additive is added and mixed with a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.), and toner 1 having an external additive (average particle diameter of 6 μm, An average circularity of 0.97 and a specific surface area of 2 m ² / g) were obtained.

[Toner 2]
To 100 parts of the obtained magenta colored particles, 3.0 parts of hydrophobic silica 2 as an external additive is added and mixed with a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.), and toner 2 having an external additive (average particle diameter of 6 μm, An average circularity of 0.97 and a specific surface area of 2 m ² / g) were obtained.

[Toner 3]
To 100 parts of the obtained magenta colored particles, 3.0 parts of hydrophobic titanium oxide 1 as an external additive is added and mixed with a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.), and toner 3 having an external additive (average particle size 6 μm) And an average circularity of 0.97 and a specific surface area of 2 m ² / g).

[Toner 4]
To 100 parts of the obtained magenta colored particles, 2.0 parts of hydrophobic silica 1 and 1.0 part of hydrophobic titanium oxide 1 are added as external additives and mixed with a Henschel mixer (Mitsui Miike Co., Ltd.). Toner 4 having an agent (average particle diameter 6 μm, average circularity 0.97, specific surface area 2 m ² / g) was obtained.

In addition, the average circularity is measured in a circle equivalent diameter-circularity scattergram based on the number of toners measured by a flow type particle image measuring apparatus. In the present invention, FPIA-2100 (Toa Medical Electronics Co., Ltd.) is used. The measurement was performed using the following formula.
Circularity = circumferential length having the same projected area as the particle image / peripheral length average circularity of the projected particle image = total circularity of each particle / total number of particles where the particle projected area is binarized toner This is the area of the particle image.

[Example 1]
In Example 1, a regenerated elastic roller was manufactured using the apparatus shown in FIG.

<Container>
The container was filled with 50 g of the porous resin particles 1 described above. A sponge roller and a polyurethane foam roller were used as the sponge roller.
The manufacturing method of the sponge roller is shown below.
Using polyether polyol, polyisocyanate and water, 1 part by mass of foam stabilizer SRX274C (trade name), and 0.1 part by weight of TOYOCAT-ET (trade name) and TOYOCAT-L33 (trade name) 0.5 as a catalyst A mass part was mixed and stirred at 25 ° C. Next, a polyurethane foam layer having a thickness of 5 mm is integrally formed around the core metal (diameter 6 mm, material SUS304) by foam molding with a sponge roller mold (material SUS304) at 50 ° C. for 20 minutes. A sponge roller was manufactured.

<Pressing member>
Polyurethane resin (thickness 0.2 mm, longitudinal length 200 mm, width 2 mm) at the end of a phosphor bronze plate (thickness 0.12 mm, longitudinal length 200 mm, width 22 mm) as a supporting member Were bonded to produce a pressing blade. The produced pressing blade was attached to the container so that the drawing pressure with the elastic roller when the elastic roller was attached was 75 N / m.

<Removal member>
As the removal member, a cylindrical removal electrode made of SUS304 having a diameter of 24 mm and a length in the longitudinal direction of 300 mm was used. The cylindrical removal electrode was provided with a DC power source for applying a potential difference between the shaft body of the elastic roller and the cylindrical removal electrode. In addition, a thermosetting polyurethane cleaning blade (thickness: 1.6 mm, length in the longitudinal direction: 300 mm, width: 10 mm) was brought into contact with the cylindrical removal electrode so that the extraction pressure was 10 N / m.

<Preparation of elastic roller with external additive>
The elastic roller was used as a developing roller and incorporated in an electrophotographic process cartridge for an electrophotographic image forming apparatus (trade name: Color Laser Jet CP3525x, manufactured by Hewlett-Packard). Further, the toner prefilled in the electrophotographic process cartridge was removed, and 250 g of toner 1 was filled instead. This was left in an environment of a temperature of 23 ° C. and a humidity of 55% RH for 24 hours. Thereafter, this electrophotographic process cartridge was loaded into the main body of the electrophotographic image forming apparatus, and 20000 images with a printing rate of 1% were output in the same environment.

  Next, the elastic roller was removed from the electrophotographic process cartridge, and air was blown onto the surface of the elastic roller to blow off the toner on the surface of the elastic roller. Thereafter, when the surface of the elastic roller was observed at a magnification of 20000 times using a scanning electron microscope, it was confirmed that a large amount of hydrophobic silica 1 as an external additive derived from toner 1 was adhered to the surface of the elastic roller. It was done. Further, almost no toner was confirmed on the surface of the elastic roller.

By the above method, an elastic roller (an elastic roller after use) to which the hydrophobic silica 1 was adhered was obtained.
The current value of this elastic roller was measured in an environment of a temperature of 23 ° C. and a humidity of 55% RH, and was defined as a current value after use. After this use, the current value of the elastic roller was 23 μA.
Here, the ratio of the current value after use to the initial current value was determined as the current value ratio after use. The current value rate after use at this time was 5%.
Similarly, a total of 50 post-use elastic rollers having a post-use current value rate of less than 10% were produced.

<External additive removal treatment attached to the elastic roller>
Next, the external additive attached to the surface of the elastic roller was removed using the external additive removing apparatus shown in FIG. After use, the elastic roller was attached to the removing device, and the rotation speed was 500 rpm in the direction of arrow a. At this time, the sponge roller 31 was rotated at 400 rpm in the direction of arrow b. Further, the cylindrical removal electrode was brought into contact with the elastic roller so as to have a drawing pressure of 100 N / m, and rotated in the direction of arrow c at 250 rpm. Further, a voltage of +200 V was applied to the cylindrical removal electrode, and the elastic roller, more specifically, the shaft core body of the elastic roller was grounded, and the potential difference between the elastic roller and the cylindrical removal electrode was set to +200 V. The above processing time was 5 minutes.

Next, the elastic roller was removed from the external additive removing device, air was blown onto the surface of the elastic roller, and the porous resin particles 1 on the surface of the elastic roller were blown off.
The current value of this elastic roller was measured in an environment of a temperature of 23 ° C. and a humidity of 55% RH, and was defined as the current value after removal. The current value of the elastic roller (regenerated elastic roller) after removing the external additive was 424 μA.
Here, the ratio of the current value after removal to the initial current value was determined as the first current value recovery rate. The current value recovery rate at this time was 94%.
The external additive generally has a higher resistance than the elastic roller, and the elastic roller becomes higher in resistance as the external additive adheres. Therefore, the current value recovery rate can be used as an index of the degree of external additive removal.

This current value recovery rate was evaluated according to the following criteria.
“A”: Current value recovery rate is 90% or more.
“B”: Current value recovery rate is 80% or more and less than 90%.
“C”: Current value recovery rate is 60% or more and less than 80%.
“D”: Current value recovery rate is 40% or more and less than 60%.
“E”: Current value recovery rate is less than 40%.

  Next, the remaining 49 post-use elastic rollers were continuously subjected to external additive removal treatment, and a total of 50 evaluations were made. Table 10 shows the results of current value recovery rates for the first, twentieth, and fifty. The initial current value shown in Table 10 is an average value of 50 elastic rollers before adhesion of the external additive.

<Image evaluation>
If the removal of the external additive is insufficient, a minute density unevenness (hereinafter referred to as “guzziness”) is generated in the image due to further deposition of the external additive on the surface of the elastic roller during reuse. Therefore, the 50th regenerative elastic roller was used, and the occurrence of roughness after reuse was evaluated.
Of the regenerated elastic rollers that were continuously subjected to the external additive removal treatment, the 50th one was replaced with the developing roller of a new electrophotographic process cartridge, and then loaded into the main body of the electrophotographic image forming apparatus. In an environment of a temperature of 23 ° C. and a humidity of 55% RH, 6000 images with a printing rate of 1% were output. Thereafter, a halftone image was printed in the same environment. The roughness was evaluated according to the following criteria.
"A": About the roughness, it is not visually confirmed at all,
"B": Slight rustling is confirmed,
“C”: The roughness is clearly confirmed.
The results are also shown in Table 10.

[Comparative Example 1]
The external additive removal process was performed in the same manner as in Example 1 except that the toner 1 was changed to the toner 2. Table 10 shows the evaluation results.

[Comparative Example 2]
The external additive removal treatment was performed in the same manner as in Example 1 except that the porous resin particles 1 were changed to the nonporous resin particles 1. Table 10 shows the evaluation results.

[Comparative Example 3]
The external additive removal treatment was performed in the same manner as in Example 1 except that the porous resin particles 1 were changed to the porous inorganic particles 1, the toner 1 was changed to the toner 2, and the voltage applied to the cylindrical removal electrode was changed to -200V. It was. Table 10 shows the evaluation results.

[Example 2]
The external additive removal treatment was performed in the same manner as in Example 1 except that the porous resin particles 1 were changed to the porous resin particles 2. Table 10 shows the evaluation results.

Example 3
The external additive removal treatment was performed in the same manner as in Example 1 except that the porous resin particles 1 were changed to porous resin particles 3, the toner 1 was changed to toner 2, and the voltage applied to the cylindrical removal electrode was changed to -200V. It was. Table 10 shows the evaluation results.

Example 4
An external additive removing process was performed in the same manner as in Example 1 except that the toner 1 was changed to the toner 3. Table 10 shows the evaluation results.

Example 5
The external additive removal process was performed in the same manner as in Example 1 except that the toner 1 was changed to the toner 4. Table 10 shows the evaluation results.

Example 6
In the production of the elastic roller, the external additive was removed in the same manner as in Example 1 except that 7.0 parts of carbon black in the elastic layer was changed to 0 parts and 20.0 parts of carbon black in the resin layer was changed to 0 parts. Processed. Table 10 shows the evaluation results.

Example 7
The production of the elastic roller was the same as in Example 1 except that 7.0 parts of carbon black in the elastic layer was changed to 15.0 parts and 20.0 parts of carbon black in the resin layer was changed to 30.0 parts. External additive removal treatment was performed. The evaluation results are shown in Table 10.

Example 8
The production of the elastic roller was the same as in Example 1 except that 7.0 parts of carbon black in the elastic layer was changed to 30.0 parts and 20.0 parts of carbon black in the resin layer was changed to 35.0 parts. External additive removal treatment was performed. Table 10 shows the evaluation results.

Example 9
Evaluation was performed using a charging roller mounted on a dedicated electrophotographic process cartridge for magenta of an electrophotographic image forming apparatus (trade name: Color Laser Jet CP3525x, manufactured by Hewlett-Packard). When the initial current value of this charging roller was measured at an applied voltage of 200 V, it was 3200 μA.
The toner prefilled in the electrophotographic process cartridge was removed, and 250 g of toner 1 was filled instead. This was left in an environment of a temperature of 23 ° C. and a humidity of 55% RH for 24 hours. Thereafter, the electrophotographic process cartridge was loaded into the main body of the electrophotographic image forming apparatus, and 20000 images with a printing rate of 1% were output in the same environment to attach external additives.
Next, the elastic roller was removed from the electrophotographic process cartridge, air was blown onto the surface of the charging roller, and the current value was measured. The current value rate after use at this time was 2%.
Similarly, a total of 50 charging rollers having external additives attached thereto were prepared. The initial current values of these charging rollers were 3000 to 3500 μA. Moreover, the current value rate after use was less than 5%.

Thereafter, the external additive removal treatment was performed in the same manner as in Example 1. Table 11 shows the evaluation results of the current value recovery rates of the first, twentieth, and fifty. The initial current values shown in Table 11 are average values of 50 charging rollers before the external additive is adhered.
In addition, when an image is formed using a charging roller having an external additive deposited on the surface, the charge amount of the drum is insufficient. When a halftone image is formed in this state, the potential on the drum becomes non-uniform and streaks are formed in the image. Therefore, again, as in Example 1, the 50th regenerative charging roller was replaced with a new electrophotographic process cartridge, and 6000 images with a printing rate of 1% were output in an environment of temperature 23 ° C. and humidity 55% RH. . Thereafter, streaks when a halftone image was printed in the same environment were evaluated according to the following criteria.
“A”: The streak is not visually confirmed at all.
“B”: slight streaks are confirmed,
“C”: A streak is clearly confirmed.
The results are also shown in Table 11.

[Comparative Example 4]
The external additive removal treatment was performed in the same manner as in Example 9 except that the toner 1 was changed to the toner 2. The evaluation results are shown in Table 11.

  From Table 11, it was found that by the production method of the present invention, a regenerative elastic roller having a stable cleaning performance that can sufficiently remove the external additive attached to the charging roller was obtained.

DESCRIPTION OF SYMBOLS 1 ... Elastic roller 10 with external additive adhered on surface · Regenerative elastic roller 11 · · · Conductive shaft core 12 · · · Elastic layer 13 · · · Surface layer 20 · · · External additive removing device 21 · · · Container 22 ... porous resin particles 23 ... pressing member 24 ... removal member 25 ... power supply 31 ... sponge roller 32 ... cleaning blade 40 ... current value measuring device 41 ... cylindrical electrode 42 ... DC power supply 43 ... ammeter 100 ... image forming apparatus 101 for electrophotography ... photoconductor 102 ... toner supply roller 103 ... toner container 104 ... toner regulating blade 105 ... developing device 106 ... laser beam 107 ... charging device 108 ... Cleaning device 109 ... Toner regulating blade bias power supply 110 ... Developing roller bias power supply 111 ... Fixing device 112 ... Drive roller 113 ... Transfer roller 114 ‥ transfer bias power source 115 ‥‥ tension roller 116 ‥‥ transfer conveyor belt 117 ‥‥ driven roller 118 ‥‥ recording medium 119 ‥‥ feed roller 120 ‥‥ suction roller 121 ‥‥ attraction bias power supply 0.99 ‥‥ electrophotographic process cartridge

Claims (3)

A method for producing a regenerative elastic roller comprising a step of removing an external additive derived from toner adhering to the surface of an elastic roller,
The process
(1) The elastic roller and the pressing member are rubbed against each other at the nip portion between the elastic roller having the external additive attached to the surface and the pressing member disposed to face the elastic roller. By supplying porous resin particles charged to a normal charging polarity opposite to the normal charging polarity of the external additive, and rubbing the porous resin particles against the surface of the elastic roller at the nip portion, Charging the porous resin particles to a normal charge polarity opposite to that of the external additive, and incorporating the external additive into the pores of the porous resin particles;
(2) The surface potential of the removal member with respect to the surface potential of the elastic roller is between the surface of the removal member disposed opposite to the elastic roller and the surface of the elastic roller. A step of imparting a potential difference that is opposite to the polarity and transferring the porous resin particles incorporating an external additive from the surface of the elastic roller to the surface of the removing member;
The manufacturing method of the reproduction | regeneration elastic roller characterized by including these.   The method for producing a regenerative elastic roller according to claim 1, wherein the external additive is silica or titanium oxide.   The method for producing a regenerative elastic roller according to claim 1, wherein the elastic roller is conductive.

Images