JP2013200503A - Charging member, charging device, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging member that suppresses the occurrence of charging unevenness.SOLUTION: A charging member includes a support 31, and an elastic layer 33 that is provided on the support 31 and contains at least absorbent and volatile oil.

Description

  The present invention relates to a charging member, a charging device, an image forming apparatus, and a process cartridge.

  In an electrophotographic image forming apparatus, a conductive roll in which an elastic layer made of a rubber composition or the like is formed on a support is applied as a charging member for charging a photoreceptor.

For example, in Patent Document 1, in a semiconductive rubber roller that includes a cored bar and a semiconductive elastic body layer provided on the outer periphery of the cored bar as a component, the elastic layer has a volume resistivity of 1 × 10. It is formed by a rubber composition containing a raw material rubber of ¹³ Ω · cm or less and a non-conductive inorganic filler, and the mass fraction of the raw material rubber with respect to the total compounding agent of the elastic layer is 50% by mass or less A semiconductive rubber roller is disclosed that satisfies the relationship of “Ω50 / Ω250 <2” where the electrical resistance of the elastic layer when 50 V is applied is Ω50 and the electrical resistance when 250 V is applied is Ω250. .

  Patent Document 2 discloses a method for producing an electrophotographic semiconductive member in which at least a thermoplastic resin, carbon black, and an adsorbent are mixed, melt-kneaded, and molded.

JP 2005-275288 A Japanese Patent Laid-Open No. 2002-169931

  An object of the present invention is to provide a charging member in which the occurrence of uneven charging is suppressed.

The above problems are solved by the present invention described below. That is,
The invention according to claim 1
A support;
An elastic layer containing at least an adsorbent and a volatile oil on the support;
A charging member having

The invention according to claim 2
The charging member according to claim 1, wherein the adsorbent is activated carbon.

The invention according to claim 3
The charging member according to claim 1, wherein the volatile oil is a cyclic siloxane.

The invention according to claim 4
A charging device comprising the charging member according to claim 1.

The invention according to claim 5
An image carrier,
The charging device according to claim 4, wherein the charging device contacts with the image carrier and charges the image carrier;
A latent image forming device that forms an electrostatic latent image on the image carrier charged by the charging device;
A developing device for developing the electrostatic latent image on the image carrier with toner to form a toner image;
A transfer device for transferring the toner image on the image carrier to a recording medium;
An image forming apparatus having

The invention according to claim 6
The charging device according to claim 4, wherein the charging device contacts the image carrier and charges the image carrier;
The image carrier, a developing device for developing an electrostatic latent image on the image carrier with toner to form a toner image, and residual toner remaining on the surface of the image carrier after the toner image is transferred to a recording medium. A cleaning device for cleaning and removing, and at least one selected from
It is a process cartridge that can be attached to and detached from the image forming apparatus.

  According to the first, second, and third aspects of the invention, there is provided a charging member in which the occurrence of uneven charging is suppressed compared to the case where the elastic layer does not satisfy the requirement that the adsorbent and the volatile oil are contained. .

  According to the fourth aspect of the present invention, there is provided a charging device in which the occurrence of uneven charging is suppressed as compared with a case where the elastic layer does not include a charging member having an elastic layer containing an adsorbent and volatile oil. .

  According to the invention of claim 5, an image in which the generation of white spots and color spots in the image is suppressed as compared with a case where the elastic layer does not include a charging member having an elastic layer containing an adsorbent and volatile oil. A forming apparatus is provided.

  According to the invention of claim 6, the process in which the generation of white spots and color spots in the image is suppressed as compared with the case where the elastic layer does not include a charging member having an elastic layer containing an adsorbent and volatile oil. A cartridge is provided.

It is a schematic sectional drawing which shows 1st Embodiment of the charging member of this embodiment. It is a schematic sectional drawing which shows 2nd Embodiment of the charging member of this embodiment. It is a schematic sectional drawing which shows 3rd Embodiment of the charging member of this embodiment. 1 is a schematic diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic diagram which shows an example of the process cartridge of this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail.

<Charging member>
The charging member according to the present embodiment includes a support, and an elastic layer containing at least an adsorbent and volatile oil on the support.

Conventionally, in an electrophotographic image forming apparatus or the like, a charging member in which an elastic layer containing rubber or the like is formed on a support has been used as a charging member. However, when an elastic material such as rubber is kneaded in order to mold the elastic layer, air may be included in the kneaded elastic material when air from outside air is involved. When air bubbles exist in the elastic layer, the ease of electricity flow changes in the air bubble part, causing uneven discharge between the part without the air bubble and the part having the air bubble, which depends locally on the resistivity and dielectric constant. In some cases, the charging property is changed to cause uneven charging.
Furthermore, when an image is formed using a charging member in which charging unevenness has occurred in an image forming apparatus, white spots or color spots may occur in the image.

  On the other hand, in the charging member according to the present embodiment, the elastic layer contains the adsorbent and the volatile oil, and bubbles in the elastic layer are reduced. As a result, the occurrence of charging unevenness is suppressed. In addition, when the charging member according to the present embodiment is used in an image forming apparatus, generation of white spots and color spots in an image is suppressed.

Although this effect is not clear, it is presumed as follows.
First of all, it is considered that bubbles generated during kneading and remaining in the elastic layer are removed by the adsorbent contained in the elastic layer.
However, although the adsorbent is effective for removing bubbles, it is difficult to remove coarse bubbles only by containing the adsorbent, and it seems that such coarse bubbles remain. On the other hand, in the charging member according to the present embodiment, the elastic layer contains volatile oil, and the viscosity of the elastic material before being sulfidized by the volatile oil (that is, before forming the elastic layer) is reduced. It is presumed that the bubbles are made finer by the pressure applied when the elastic layer is formed. In other words, bubbles remaining in the kneading step of the elastic material constituting the elastic layer and the molding step of forming the elastic layer are refined and become easily adsorbed by the adsorbent, and the bubbles remain in the elastic layer. It is considered to be suppressed.

  In addition, most of the volatile oil can be volatilized through a heating step such as vulcanization performed when the elastic layer is formed, so that occurrence of bleeding due to remaining oil can be suppressed.

  In the present embodiment, “volatile oil” refers to oil that evaporates at a temperature equal to or lower than the temperature applied when the elastic layer is molded (for example, injection molding).

In the present embodiment, the “adsorbent” represents a substance that adsorbs the following amount of gas when confirmed by the following method.
First, a method for measuring the degree of adsorption of the adsorbent will be described. The equilibrium adsorption capacity is calculated by the following equation (1) from the increase in the sample when the mass becomes constant by blowing a constant amount (2 L / min) of air onto the adsorbent.
Formula (1) Equilibrium adsorption capacity = (increase in sample / mass of sample) × 100 (mass%)
In the present specification, the adsorbent has an equilibrium adsorption capacity of 2% by mass or more.

  Hereinafter, the configuration of the charging member of the present embodiment will be described in detail.

  The layer structure of the charging member is not particularly limited as long as at least an elastic layer is formed on the support. An embodiment having a surface layer on the elastic layer or an adhesive layer between the support and the elastic layer. It is also possible to adopt an aspect in which the intermediate layer is formed on the outer peripheral side of the elastic layer.

Here, the aspect of the charging member according to the present embodiment will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a first embodiment of a charging member according to the present embodiment. In FIG. 1, an elastic layer 33 is coated on a cylindrical support 31 via an adhesive layer 32, and a surface layer 34 is coated on the outer peripheral side of the elastic layer 33.

  FIG. 2 is a schematic cross-sectional view showing a second embodiment of the charging member according to the present embodiment. In FIG. 2, an elastic layer 33 is coated on a cylindrical support 31 via an adhesive layer 32, an intermediate layer 35 is coated on the outer peripheral side of the elastic layer 33, and a surface is further formed on the outer peripheral side of the intermediate layer 35. Layer 34 is coated. Examples of the intermediate layer 35 include a resistance adjustment layer.

  FIG. 3 is a schematic cross-sectional view showing a third embodiment of the charging member according to the present embodiment. In FIG. 3, an elastic layer 33 is coated on a cylindrical support 31, and a surface layer 34 is coated on the outer peripheral side of the elastic layer 33.

  Next, each layer constituting the charging member will be described.

(Support)
The support is a cylindrical member that functions as an electrode and a support member for the charging member. Examples of the material include metals such as iron (free cutting steel, etc.), copper, brass, stainless steel, aluminum, nickel, and the like. . Further, examples of the support include a member (for example, a resin or ceramic member) whose outer surface is plated, a member in which a conductive agent is dispersed (for example, a resin or ceramic member), and the like. The support may be a hollow member (tubular member) or a non-hollow member.

(Elastic layer)
The elastic layer contains at least an adsorbent and volatile oil, and further contains an elastic material. In addition to these, a conductive agent and other additives may be included.

-Volatile oil Volatile oil represents the oil vaporized below the temperature given when an elastic layer is shape | molded (for example, injection molding etc.) as above-mentioned.

Examples of the volatile oil include cyclic siloxane.
The cyclic siloxane represents a compound having a cyclic molecular structure based on a siloxane bond (Si—O—Si), and in this embodiment, a trimer, a tetramer, and a pentamer are particularly preferable.
In particular,
Hexamethylcyclotrisiloxane (C ₆ H ₁₈ O ₃ Si ₃ , melting temperature 64 ° C., boiling point 134 ° C., vaporization temperature 134 ° C.)
Octamethylcyclotetrasiloxane (C ₈ H ₂₄ O ₄ Si ₄ , melting temperature 18 ° C., boiling point 175 ° C., vaporization temperature 175 ° C.)
Decamethylcyclopentasiloxane (C ₁₀ H ₃₀ O ₅ Si ₅ , melting temperature −30 ° C., boiling point 210 ° C., vaporization temperature 210 ° C.)
Dodecanolactam methylcyclohexane siloxane _{(C 12 H 36 O 6 Si} 6, melting temperature -3 ° C., boiling point 245 ° C., the vaporization temperature of 245 ° C.)
And cyclo (dimethylsiloxane) s such as
In addition, 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane, , 3,5,7,9-pentamethyl-1,3,5,7,9-pentaphenylcyclopentasiloxane and other cyclo (methylphenylsiloxane) s, hexaphenylcyclotrisiloxane and other cyclo (diphenylsiloxanes), Fluorine-containing cyclosiloxanes such as 3- (3,3,3-trifluoropropyl) methylcyclotrisiloxane, methylhydrosiloxane mixtures, hydrosilyl group-containing cyclosiloxanes such as pentamethylcyclopentasiloxane and phenylhydrocyclosiloxane, penta Vinyl, such as vinyl pentamethylcyclopentasiloxane Containing cyclosiloxanes, and the like.

  The vaporization temperature of the volatile oil is specifically preferably 100 ° C. or higher and 200 ° C. or lower, and more preferably 150 ° C. or higher and 190 ° C. or lower.

The viscosity of the volatile oil is preferably 1 Pa · S or more and 100 Pa · S or less, more preferably 5 Pa · s or more and 30 Pa · s or less.
The viscosity is measured in an environment of 23 ° C. and 55% RH using a viscometer (RE550) manufactured by Toki Sangyo Co., Ltd. It is obtained by placing volatile oil on a fixed flat plate, bringing the flat plate into contact with the top, allowing it to flow at a constant speed, and measuring the force applied at that time.

The addition rate of volatile oil in the composition for forming the elastic layer is preferably 1% by mass or more and 10% by mass or less, more preferably 3% by mass or more and 8% by mass or less, More preferably, it is 4 mass% or more and 6 mass% or less.
When the addition rate is equal to or higher than the lower limit, the viscosity of the composition for forming the elastic layer is lowered, and the remaining bubbles can be efficiently refined. On the other hand, when the addition rate is less than or equal to the above upper limit value, it is suppressed that the bubbles are not miniaturized, and surface defects due to surface irregularities due to bubble bursting or remaining as bubbles in foreign matter are suppressed. .

  The volatile oil is vaporized at a temperature lower than the temperature given when the elastic layer is molded (for example, injection molding). Therefore, most of the volatile oil is subjected to a heating process such as vulcanization performed when forming the elastic layer. Can volatilize.

-Adsorbent An adsorbent represents the substance whose equilibrium adsorption capacity calculated | required by the above-mentioned method is the said value.
The equilibrium adsorption capacity of the adsorbent is preferably 2% by mass or more and 20% by mass or less.

Examples of the adsorbent include activated carbon, alumina, silica gel, zeolite, and the like.
Among these, activated carbon is particularly preferable.

The activated carbon refers to a porous substance obtained by reacting with a gas or a chemical at a high temperature using a carbon substance (for example, coal or palm grain) as a raw material.
A commercial item may be used as activated carbon, for example, the Tokyo Chemical Industry Co., Ltd. make, brand name: Charcoal Activated (equilibrium adsorption capacity: 10 mass%) etc. are mentioned.

The content (solid content ratio) of the adsorbent contained in the elastic layer is preferably 1% by mass or more and 10% by mass or less, more preferably 2% by mass or more and 8% by mass or less. More preferably, it is 3 mass% or more and 6 mass% or less.
When the content is equal to or higher than the above lower limit, the reduction of bubbles in the elastic layer is efficiently achieved. On the other hand, when the content is less than or equal to the above upper limit, the disadvantage of deterioration of electrical characteristics as a charging member is suppressed.

-Elastic materials Elastic materials include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, polyurethane, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin. -Ethylene oxide-allyl glycidyl ether copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), natural rubber, and blended rubbers thereof. Among these, polyurethane, silicone rubber, EPDM, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, NBR and blended rubbers thereof are desirably used. These elastic materials may be foamed or non-foamed.

-Conductive agent As a conductive agent, an electronic conductive agent and an ionic conductive agent are mentioned. 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 And 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 ; These conductive agents may be used alone or in combination of two or more.

  The addition amount of the conductive agent is not particularly limited, but in the case of the electronic conductive agent, it is preferably in the range of 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the elastic material. It is more desirable that the amount be in the range of parts by mass or less. On the other hand, in the case of the ionic conductive agent, it is desirable that the amount be in the range of 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the elastic material, and 0.5 to 3.0 parts by weight. The following range is more desirable.

Other additives Examples of other additives blended in the elastic layer include softeners, plasticizers, curing agents, vulcanizing agents, vulcanization accelerators, antioxidants, surfactants, coupling agents, and fillers. Examples thereof include materials that can be usually added to the elastic layer, such as agents (silica, calcium carbonate, etc.).

-Physical properties of the elastic layer The thickness of the elastic layer varies depending on the device to which the charging member is applied, but is preferably 0.5 mm to 4.0 mm, and more preferably 0.5 mm to 2.5 mm. desirable.

The volume resistivity of the elastic layer varies depending on the device to which the charging member is applied. However, when the charging member is used in a charging device of an electrophotographic image forming apparatus described later, for example, 10 ³ Ωcm or more and 10 ^14. It is preferably Ωcm or less, more preferably 10 ⁴ Ωcm or more and 10 ¹⁰ Ωcm or less, and further preferably 10 ⁵ Ωcm or more and 10 ⁹ Ωcm or less.
The volume resistivity is measured with respect to a sheet-like measurement sample by using a measuring jig (R12702A / B resiliency chamber: manufactured by Advantest) and a high resistance measuring device (R8340A digital high resistance / microammeter: Advantest). The voltage adjusted so that the electric field (applied voltage / composition sheet thickness) is 1000 V / cm is calculated from the current value after application for 30 seconds using the following formula (2).
Volume resistivity (Ω · cm) = (19.63 × applied voltage (V)) / (current value (A) × measurement sample sheet thickness (cm)) (2)

Also, the hardness of the elastic layer varies depending on the apparatus to which the charging member is applied, but when the charging member is used for a charging device of an electrophotographic image forming apparatus described later, the Asker C hardness is 15 ° or more and 90 ° or less. Or a range of 15 ° to 70 °.
The Asker C hardness was measured under the condition of a load of 1000 g by pressing a measuring needle of an Asker C type hardness meter (manufactured by Kobunshi Keiki Co., Ltd.) on the surface of a measurement sheet having a thickness of 3 mm.

-Formation of elastic layer The elastic layer is prepared, for example, by kneading a mixture of the above-mentioned components to prepare a composition for forming an elastic layer, and using an injection molding machine or a press molding machine on the support. It is formed by extruding and vulcanizing the composition.
In addition, as temperature at the time of extruding on a support body, 50 degreeC or more and 120 degrees C or less are preferable, and also 60 degreeC or more and 100 degrees C or less are more preferable. The vulcanization temperature is preferably 140 ° C. or higher and 200 ° C. or lower, and more preferably 160 ° C. or higher and 190 ° C. or lower.

(Surface layer)
In the charging member of this embodiment, a surface layer may be formed on the elastic layer.
Examples of the surface layer include a surface layer composed of a resin, and further include a conductive agent, particles for imparting irregularities (specific surface roughness) to the surface of the surface layer, and other additives. It may be constituted by.

  Resins include acrylic resin, cellulose resin, polyamide resin, copolymerized nylon, polyurethane resin, polycarbonate resin, polyester resin, polyethylene resin, polyvinyl resin, polyarylate resin, styrene butadiene resin, melamine resin, epoxy resin, urethane resin, silicone Examples thereof include resins, fluororesins (for example, tetrafluoroethylene perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, polyvinylidene fluoride, etc.), urea resins, and the like. Here, the copolymer nylon includes one or more of 610 nylon, 11 nylon, and 12 nylon as polymerized units, and other polymer units included in the copolymer include , 6 nylon, 66 nylon and the like.

  Examples of the conductive agent blended in the surface layer include an electronic conductive agent and an ionic conductive agent. 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 And 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 ; These conductive agents may be used alone or in combination of two or more.

  Here, as a commercial product of carbon black, specifically, “Special Black 350”, “Special Black 100”, “Special Black 250”, “Special Black 5”, and “Special Black 4” manufactured by Degussa Co., Ltd. "Special Black 4A", "Special Black 550", "Special Black 6", "Color Black FW200", "Color Black FW2", "Color Black FW2V", "MONARCH1000" manufactured by Cabot Corporation , “MONARCH1300” manufactured by Cabot Corporation, “MONARCH1400” manufactured by Cabot Corporation, “MOGUL-L”, “REGAL400R”, and the like.

The particles for imparting irregularities (specific surface roughness) to the surface of the surface layer may be either conductive particles or non-conductive particles, but non-conductive particles are desirable. As electroconductive particle, the particle | grains of the material quoted as the said electrically conductive agent mix | blended with an elastic layer are mentioned. Non-conductive particles include resin particles (polyimide resin particles, methacrylic resin particles, polystyrene resin particles, fluorine resin particles, silicone resin particles, etc.), inorganic particles (clay particles, kaolin particles, talc particles, silica particles, alumina particles, etc.) ), Or ceramic particles. The particles may be particles composed of the same kind of resin as the resin. Here, the conductivity means that the volume resistivity is less than 10 ¹³ Ωcm, and the non-conductivity means that the volume resistivity is 10 ¹³ Ωcm or more. The same applies to other cases.

Examples of the other additive in the surface layer include materials that can be added to the normal surface layer such as a curing agent, a vulcanizing agent, a vulcanization accelerator, an antioxidant, a surfactant, and a coupling agent.
The thickness of the surface layer is desirably 2 μm or more and 25 μm or less. The volume resistivity of the surface layer is preferably 10 ³ Ωcm or more and 10 ¹⁴ Ωcm or less.

The surface layer is prepared by dispersing the resin, conductive agent, and the like in a solvent to prepare a coating solution, and applying the coating solution on the elastic layer prepared in advance. Examples of the application method of the coating liquid include a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method.
The solvent used in the coating solution is not particularly limited, and general solvents are used. For example, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; diethyl ether and dioxane A solvent such as ethers may be used.

<Image forming apparatus, process cartridge>
Hereinafter, a case where the charging member of the present embodiment is mounted on an image forming apparatus and a charging device of a process cartridge will be described.
FIG. 4 is a schematic configuration diagram illustrating the image forming apparatus according to the present embodiment. FIG. 5 is a schematic configuration diagram showing a process cartridge according to the present embodiment.

  As shown in FIG. 4, the image forming apparatus 100 according to the present embodiment includes an image carrier 13, and a charging device 19 that charges the image carrier 13 and an image carrier charged by the charging device 19 around the image carrier 13. A latent image forming device 17 for exposing the body 13 to form a latent image; a developing device 16 for developing the electrostatic latent image formed by the latent image forming device 17 with toner to form a toner image; A transfer device 18 that transfers the formed toner image to the recording medium P and a cleaning device 20 that removes residual toner on the surface of the image holding member 13 after transfer are provided. Further, a fixing device 22 for fixing the toner image transferred to the recording medium P by the transfer device 18 is provided.

  In the image forming apparatus 100 according to the present embodiment, the charging device 19 includes the charging member 10 according to the present embodiment. The charging member 10 is disposed in contact with the surface of the image holding member 13 and charges the image holding member 13 by being supplied with power from a power supply device (not shown).

  In the image forming apparatus 100 of the present embodiment, known configurations are conventionally applied as the components of the electrophotographic image forming apparatus, except for the charging member 10 provided in the charging device 19. Hereinafter, an example of each configuration will be described.

  The image carrier 13 is not particularly limited, and a known photoreceptor can be used. An organic photoreceptor having a so-called function separation type structure in which a charge generation layer and a charge transport layer are separated is preferably used. Further, the image carrier 13 whose surface layer is covered with a protective layer having a charge transporting property and a crosslinked structure is also suitably applied. A photoconductor containing a siloxane-based resin, a phenol-based resin, a melamine resin, a guanamine resin, or an acrylic resin as a crosslinking component of the protective layer is also suitably applied.

  As the latent image forming device 17, for example, a laser optical system, an LED array, or the like is applied.

  For example, the developing device 16 brings a developer holding body having a developer layer formed on the surface thereof into contact with or close to the image holding body 13, and attaches toner to the electrostatic latent image on the surface of the image holding body 13. Form an image. As a developing method of the developing device 16, a developing method using a two-component developer is suitably applied as a known method. Examples of the developing method using the two-component developer include a cascade method and a magnetic brush method.

  As the transfer device 18, for example, either a non-contact transfer method such as corotron or a contact transfer method in which a conductive transfer roll is brought into contact with the image carrier 13 via the recording medium P to transfer a toner image to the recording medium P. May be adapted.

  The cleaning device 20 is a member that removes toner, paper dust, dust, and the like attached to the surface by bringing a plate-like member into direct contact with the surface of the image carrier 13, for example. As the cleaning device 20, a brush-like member, a roll-like member, or the like may be applied in addition to the plate-like member.

  An example of the fixing device 22 is a heat fixing device. The heat fixing device includes, for example, a fixing roller in which a so-called release layer is formed of a heat-resistant resin coating layer or a heat-resistant rubber coating layer on the outer peripheral surface thereof with a heater lamp for heating inside a cylindrical metal core, A pressure roller or a pressure belt that is disposed in contact with the fixing roller at a specific contact pressure and has a heat-resistant elastic body layer formed on the outer peripheral surface of the cylindrical core metal or the surface of the belt-like base material. . The fixing process of the unfixed toner image is performed by, for example, inserting a recording medium P on which the unfixed toner image is transferred between a fixing roller and a pressure roller or a pressure belt, and binding resin in the toner, Fixing by heat melting of additives and the like.

  The image forming apparatus 100 according to the present embodiment is not limited to the above-described configuration. For example, an intermediate transfer type image forming apparatus using an intermediate transfer member and a so-called image forming unit that forms toner images of respective colors are arranged in parallel. A tandem image forming apparatus may be used.

  On the other hand, as shown in FIG. 5, the process cartridge of the present embodiment is provided with an opening 24A for exposure, an opening 24B for static elimination exposure, and a mounting rail 24C in the image forming apparatus 100 shown in FIG. The electrostatic latent image formed by the image carrier 13, the charging device 19 that charges the image carrier 13 and has the charging member, and the latent image forming device 17 is developed with toner by the housing 24, and the toner. This is a process cartridge 102 configured to integrally hold a developing device 16 that forms an image and a cleaning device 20 that removes residual toner on the surface of the image carrier 13 after transfer. The process cartridge 102 is detachably attached to the image forming apparatus 100 shown in FIG.

  The process cartridge of the present embodiment is not particularly limited as long as the charging device 19 includes the charging member of the present embodiment. For example, in addition to the charging device 19, the image carrier 13 and the developing device 16 are used. And at least one type selected from the cleaning device 20, and a mode in which the image forming device 100 is detachably mounted. In addition, as shown in FIG. 5, the developing device 16 and the cleaning device 20 may be combined integrally.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited by the following Example. Unless otherwise specified, “part” means “part by mass”.

[Example 1]
[Preparation of support]
First, a support A having a barrier layer formed on the outer peripheral surface was obtained by the following method.
The barrier layer was formed by plating with chromium and nickel by an electrolytic plating method.

[Formation of elastic layer]
A mixture having the following composition is kneaded with an open roll to prepare an elastic layer forming composition, and the elastic layer forming composition is extruded onto the surface of the support A using a press molding machine, and vulcanized at 180 ° C. As a result, an elastic layer having a diameter of 14 mm was formed.
・ Rubber material (epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, Gechron 3106, manufactured by Nippon Zeon Co., Ltd.) 100 parts ・ Conducting agent (carbon black, Asahi Thermal, manufactured by Asahi Carbon Co.) 15 parts ・ Conducting agent (Ketjen Black EC, 5 parts, ionic conductive agent (lithium perchlorate) 1 part, vulcanizing agent (sulfur, 200 mesh, manufactured by Tsurumi Chemical Co., Ltd.) 1 part, vulcanization accelerator (Noxeller DM, Ouchi Shinsei Chemical Industry) 2.0 parts ・ Vulcanization accelerator (Noxeller TT, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 0.5 parts ・ Vulcanization accelerator (Zinc oxide, one type of zinc oxide, manufactured by Shodo Chemical Industry Co., Ltd.) 3 parts stearic acid 1.5 parts adsorbent (activated carbon: manufactured by Tokyo Chemical Industry Co., Ltd., trade name: Charcoal Activated, adsorbed amount: 10% by mass) 10 parts volatile oil (cyclic silo Xane: Hexamethylcyclotrisiloxane, manufactured by Tokyo Chemical Industry Co., Ltd., vaporization temperature: 134 ° C. 10 parts The content (mass%) of activated carbon and volatile oil in the elastic layer forming composition is shown in Table 1 below.

[Formation of surface layer]
A dispersion obtained by dispersing a mixture having the following composition in a bead mill is diluted with methyl ethyl ketone, dip-coated on the surface of the elastic layer, and then heated and dried at 180 ° C. for 30 minutes to form a surface layer having a thickness of 7 μm. Thus, a charging roll was obtained.
・ Polymer material (saturated copolymer polyester resin solution, Byron 30SS, manufactured by Toyobo Co., Ltd.)
100 parts, curing agent (amino resin solution, Super Becamine G-821-60, manufactured by DIC Corporation)
26.3 parts-Conductive agent (carbon black, MONARCH1000, manufactured by Cabot Corporation) 10 parts

[Examples 2 to 8 and Comparative Examples 1 to 5]
A charging roll was prepared by the method described in Example 1 except that the amount of adsorbent (activated carbon) added, the type of volatile oil (cyclic siloxane) and the amount added were changed to those shown in Table 1 below.

≪Evaluation≫
-Image quality evaluation-
The charging rolls obtained in Examples and Comparative Examples are mounted on a drum cartridge of a color copying machine DocuCenter Color a450 (manufactured by Fuji Xerox Co., Ltd.), in a low temperature and low humidity (10 ° C., 15% RH) environment, and in a high temperature and high humidity A 50% halftone image was formed in an environment (28 ° C., 85% RH), and the image quality was evaluated according to the following evaluation criteria.
The results are shown in Table 1.
-Image quality evaluation criteria ◎: White spots and color spots have not occurred ○: White spots and color spots have partially occurred (no problem in actual use)
Δ: Minor white spots and color spots occur (may cause problems in actual use)
×: White spots and color spots occur (problems in actual use)

-Bubble generation evaluation-
The charging rolls obtained in the examples and comparative examples were cut together with the surface layer and the elastic layer in the axial direction, and the presence or absence of bubbles was confirmed visually.
The results are shown in Table 1.
・ Bubble evaluation criteria ◎: Bubbles are not generated ○: Bubbles are generated alone (no image quality defect)
Δ: Air bubbles are slightly generated (image quality may be defective, which may cause problems in actual use)
×: Many bubbles are generated (defects in image quality, causing problems in actual use)

  In Table 1, “A” of the cyclic siloxane species represents “hexamethylcyclotrisiloxane (Tokyo Kasei Chemical Co., Ltd.)”, and “B” represents “octamethylcyclotetrasiloxane (Tokyo Kasei Chemical Co., Ltd.). , Vaporization temperature 175 ° C., viscosity 10 Pa · s)) ”.

DESCRIPTION OF SYMBOLS 10 Charging member, 13 Image holding body, 16 Developing device, 17 Latent image forming device, 18 Transfer device, 19 Charging device, 20 Cleaning device, 22 Fixing device, 24C Mounting rail, 24A Opening, 24B Opening, 24 Case , 31 support, 32 adhesive layer, 33 elastic layer, 34 surface layer, 35 intermediate layer, 100 image forming apparatus, 102 process cartridge, P recording medium

Claims (6)

A support;
An elastic layer containing at least an adsorbent and a volatile oil on the support;
A charging member.   The charging member according to claim 1, wherein the adsorbent is activated carbon.   The charging member according to claim 1, wherein the volatile oil is a cyclic siloxane.   A charging device comprising the charging member according to claim 1. An image carrier,
The charging device according to claim 4, wherein the charging device contacts with the image carrier and charges the image carrier;
A latent image forming device that forms an electrostatic latent image on the image carrier charged by the charging device;
A developing device for developing the electrostatic latent image on the image carrier with toner to form a toner image;
A transfer device for transferring the toner image on the image carrier to a recording medium;
An image forming apparatus. The charging device according to claim 4, wherein the charging device contacts the image carrier and charges the image carrier;
The image carrier, a developing device for developing an electrostatic latent image on the image carrier with toner to form a toner image, and residual toner remaining on the surface of the image carrier after the toner image is transferred to a recording medium. A cleaning device for cleaning and removing, and at least one selected from
A process cartridge attached to and detached from the image forming apparatus.