JP2017068225A - Image carrier protective agent, protective layer forming apparatus, image forming method, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image carrier protective agent which has all performances of excellent formability, protective property of an image carrier, pollution prevention of charging means, and cleaning property.SOLUTION: There is provided an image carrier protective agent which contains fatty acid metal salt and an inorganic lubricant, where the inorganic lubricant contains a first inorganic lubricant having tap density of 0.30 g/cmor more and 0.8 g/cmor less, the inorganic lubricant further contains a second inorganic lubricant having tap density of 0.25 g/cmor less, the first inorganic lubricant is boron nitride, and the second inorganic lubricant is at least one selected from mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, silica, graphite, a polymethyl methacrylate resin, a polytetrafluoroethylene resin, melamine formaldehyde, organic molybdenum, and a silicone resin.SELECTED DRAWING: None

Description

  The present invention relates to an image carrier protecting agent, a protective layer forming apparatus, an image forming method, an image forming apparatus, and a process cartridge.

  Conventionally, an electrophotographic image forms an electrostatic latent image by an electrostatic charge on an image carrier, and a charged toner is attached to the electrostatic latent image by a developing means to form a visible image. The visible image is formed by transferring onto a recording medium.

  The toner that has not been transferred may remain on the image carrier after the visible image is transferred onto the recording medium, and an electrostatic latent image is formed with the toner remaining on the image carrier. Then, since uniform charging of the image carrier is hindered, the toner remaining on the image carrier after the transfer is removed by a cleaning process, and then charging is performed. In order to prevent toner from remaining on the transferred image carrier, an image carrier protective agent containing an inorganic lubricant such as a fatty acid metal salt and boron nitride is applied to the surface of the image carrier. Things have been done.

However, the stress due to the friction between the image carrier and the cleaning means in the cleaning step causes the image carrier to wear and scratches the image carrier, and filming of the image carrier cannot be prevented. May be less protective of the body. Further, contamination of the charging means may occur, and toner slippage during the cleaning process may not be sufficiently prevented.
Therefore, it contains a fatty acid metal salt and boron nitride, and the boron nitride has a crystal grain size of 0.1 μm to 1.0 μm and a secondary particle size of 3.0 μm to 14.0 μm. An image carrier protecting agent has been proposed (see, for example, Patent Document 1).
Further, there has been proposed an image carrier protecting agent containing a fatty acid metal salt and boron nitride, wherein the oxygen content of the boron nitride is 0.4 wt% to 4.5 wt% (for example, Patent Document 2). reference).
Furthermore, a protective layer forming apparatus having a protective agent block containing a fatty acid metal salt, a core material, and a roller-shaped image carrier protective agent supply member has been proposed (for example, see Patent Document 3).

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image carrier protecting agent that is excellent in moldability and has all the performances of protecting an image carrier, preventing contamination of charging means, and cleaning properties.

The image carrier protective agent of the present invention as a means for solving the above-mentioned problems contains a fatty acid metal salt and an inorganic lubricant, and the inorganic lubricant is 0.30 g / cm ³ or more and 0.8 g / cm. ^A first inorganic lubricant having a tap density of ³ or less is included.

  According to the present invention, it is possible to provide an image carrier protecting agent that is excellent in moldability and has all the performances of protecting the image carrier, preventing contamination of the charging means, and cleaning properties.

FIG. 1A is a schematic cross section showing an example of an open-cell foam layer. FIG. 1B is a schematic cross-sectional view showing an example of a closed cell foam layer. FIG. 2A is a side view showing an example of an image carrier protecting agent supply member. FIG. 2B is an enlarged schematic view showing an example of an exposed surface of the continuous foam type foam layer. FIG. 3 is a schematic view showing an example of the protective layer forming apparatus of the present invention. FIG. 4 is a schematic view showing an example of the image forming apparatus of the present invention. FIG. 5 is a schematic view showing an example of the process cartridge of the present invention.

(Image carrier protective agent)
The image carrier protecting agent of the present invention contains a fatty acid metal salt and an inorganic lubricant, and the inorganic lubricant has a tap density of 0.30 g / cm ³ or more and 0.8 g / cm ³ or less. It contains an inorganic lubricant and, if necessary, further contains other components.
The image carrier protective agent of the present invention is a conventional image carrier protective agent containing a fatty acid metal salt and boron nitride as an inorganic lubricant. The average particle size, secondary particle size, and oxygen content of the boron nitride It is said that it is impossible to combine all the performance of the image carrier protecting agent, the protection of the image carrier, the protection of the image carrier, the prevention of contamination of the charging means, and the cleaning property only by setting the physical property value such as the amount within a predetermined range. Based on knowledge. Further, in the above-mentioned cleaning process, there is a problem that there is a problem that a “blade squeal” is generated in which vibration occurs when the cleaning blade or the coating blade and the image carrier are rubbed, and abnormal noise is generated at that time. Is based.

<Fatty acid metal salt>
There is no restriction | limiting in particular as said fatty acid metal salt, According to the objective, it can select suitably.

  The fatty acid metal salt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, stearin Strontium acid, calcium stearate, cadmium stearate, magnesium stearate, zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, Cobalt palmitate, lead palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, ricino Le zinc, cadmium ricinoleate, zinc laurate, cobalt laurate, lauric, lead and the like magnesium laurate. These may be used individually by 1 type and may use 2 or more types together. Among these, zinc stearate, calcium stearate, and zinc laurate are preferable because they are excellent in cleaning properties and image carrier protection, inexpensive, and very hydrophobic. Zinc is more preferred.

  There is no restriction | limiting in particular as a structure of the said fatty-acid metal salt, According to the objective, it can select suitably, For example, a lamellar crystal structure etc. are mentioned.

  There is no restriction | limiting in particular as content of the said fatty-acid metal salt, Although it can select suitably according to the objective, 70 to 98 mass% is preferable with respect to the said image carrier protective agent whole quantity, 75 More preferably, it is at least 95% by mass. When the content is 70% by mass or more and 98% by mass or less, all the performances of the image carrier protecting property, the prevention of contamination of the charging means, the cleaning property, and the image carrier protecting agent moldability are good. .

<Inorganic lubricant>
The inorganic lubricant is a compound that cleaves and lubricates itself or causes internal slip.
The inorganic lubricant preferably includes a first inorganic lubricant and further includes a second inorganic lubricant.

  The inorganic lubricant (first inorganic lubricant and second inorganic lubricant) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, mica, boron nitride, molybdenum disulfide, Examples include tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, graphite, polymethyl methacrylate resin (PMMA), polytetrafluoroethylene resin (PTFE), melamine formaldehyde, organic molybdenum, and silicone resin. These may be used individually by 1 type and may use 2 or more types together. Among these, as the first inorganic lubricant, boron nitride and mica are preferable, and hexagonal mesh surfaces in which atoms are firmly combined overlap with each other at a wide interval, and only the weak van der Waals force connects the layers. Therefore, boron nitride is more preferable from the viewpoint that the interlayer easily cleaves and lubricates.

As the tap density of the first inorganic lubricant, 0.30 g / cm ³ or more 0.8 g / cm ³ or less, preferably 0.30 g / cm ³ or more 0.7 g / cm ³ or less, 0.35 g / Cm ³ or more and 0.6 g / cm ³ or less is more preferable. When the tap density is 0.30 g / cm ³ or more, the fluidity as a powder is good, the protection of the image carrier is improved, the cleaning property is improved, the charging means is prevented from being contaminated, and the image carrier is protected. The moldability of the agent can be improved. When the tap density is 0.8 g / cm ³ or less, although the fluidity as a powder is high, it is difficult to laminate an inorganic lubricant on the image carrier and the protection of the image carrier is improved. it can. When the tap density is within the preferred numerical range, the fluidity as a powder and the film formability on the image carrier are adjusted to appropriate levels, so that the protection of the image carrier is improved and the cleaning property is improved. Improvement, prevention of charging unit contamination, and improvement in moldability of the image carrier protecting agent can be achieved at the same time.
As the tap density of the second inorganic lubricant is preferably 0.25 g / cm ³ or less, 0.15 g / cm ³ or more 0.25 g / cm ³ or less, more preferably, 0.2 g / cm ³ or more zero. Particularly preferred is 25 g / cm ³ or less. When the tap density is 0.25 g / cm ³ or less, the fluidity of the particles tends to be low and the cohesiveness tends to be strong. By laminating at the edge of the blade, the particles stabilize the behavior of the blade. , Blade noise can be suppressed.
By using the first inorganic lubricant and the second inorganic lubricant in combination, high film formation efficiency and lubricity can be obtained, and blade squealing can be suppressed.
The tap density can be measured using a powder characteristic evaluation apparatus (apparatus name: Powder Tester (registered trademark) PT-X, manufactured by Hosokawa Micron Corporation). Specifically, using a powder characterization cylinder (device name: Powder Tester (registered trademark) PT-X, manufactured by Hosokawa Micron Co., Ltd.) and using a glass graduated cylinder, conforms to Japanese Pharmacopoeia and US Pharmacopoeia Can be measured.

The number average primary particle size of the inorganic lubricant is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.1 μm or more and 10 μm or less. Within the preferable numerical range, it is possible to improve the cleaning property and the protection property of the image carrier.
Examples of the number average primary particle size of the inorganic lubricant include, for example, an image observed with a scanning electron microscope (SEM) (thermal F-SEM, manufactured by Zeiss, ULTRA55), image analysis / measurement software (Image-pro plus). 4.0j, manufactured by Media Cybernetics), and can be obtained by averaging the 10 of them.

The first inorganic lubricant is not particularly limited as long as the tap density is 0.30 g / cm ³ or more and 0.8 g / cm ³ or less, and a commercially available product can be used. Examples of the commercially available product include boron nitride, trade name: HP-2W (manufactured by Mizushima Alloy Iron Co., Ltd., tap density: 0.3 g / cm ³ ); trade name: PCTP5 (tap density: 0.3 g / cm ³ ), trade name: PCTP8 (tap density: 0.5 g / cm ³ ), trade name: PCTL30 (tap density: 0.6 g / cm ³ ), (above, manufactured by Saint-Gobain), trade name: MGP (electrochemical) Kogyo Corporation, tap density 0.8 g / cm ³ ); trade name: HP-1CAW (manufactured by Mizushima Alloy Iron Co., Ltd., tap density: 0.8 g / cm ³ ). These may be used individually by 1 type and may use 2 or more types together.
The second inorganic lubricant is not particularly limited as long as the tap density is 0.25 g / cm ³ or less, and a commercially available product can be used. Examples of the commercially available product include boron nitride, trade name: NX1 (manufactured by Momentive Performance Materials Japan, tap density: 0.12 g / cm ³ ); trade name: PCTP2 (manufactured by Saint-Gobain, tap density: 0). .2g / ^cm 3); trade name: HP-P1 (Mizushima alloy Co., Ltd., tap density: 0.25g / ^cm 3), as mica, trade name: Y-3000 (Corporation Yamaguchi mica Co., Ltd., tap density: 0.25 g / cm ³ ). These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as content of the said inorganic lubricant, Although it can select suitably according to the objective, 2 mass% or more and 30 mass% or less are preferable with respect to the said image carrier protective agent whole quantity, 5 More preferably, it is at least 25% by mass. When the content is 2% by mass or more, the amount of film formation becomes appropriate, contamination of the charging means can be prevented, and cleaning properties can be improved. Further, when the content is 30% by mass or less, the protective property of the image carrier is good.

[Mass ratio (fatty acid metal salt / inorganic lubricant)]
The mass ratio (fatty acid metal salt / inorganic lubricant) between the content (mass%) of the fatty acid metal salt and the content (mass%) of the inorganic lubricant is preferably 70/30 or more and 98/2 or less. 75/25 or more and 95/5 or less is more preferable. When the mass ratio (fatty acid metal salt / inorganic lubricant) is 70/30 or more, the amount of film formation of the inorganic lubricant is increased, the contamination of the charging means can be prevented, and the cleaning property can be improved. When it is below, it is possible to improve the protection of the image carrier and the moldability of the image carrier protective agent. Further, when the mass ratio (fatty acid metal salt / inorganic lubricant) is within a preferable numerical range, the film forming property by the inorganic lubricant is improved, the charging means can be prevented from being contaminated, the cleaning property, and the image carrier protection. And the moldability of the image carrier protecting agent can be improved.

<Other ingredients>
The other components are not particularly limited and may be appropriately selected depending on the intended purpose. For example, inorganic particles such as silica, alumina, ceria, zirconia, clay, calcium carbonate, or surface hydrophobized particles thereof. Organic particles such as polymethyl methacrylate particles, polystyrene particles, silicone resin particles, α-olefin-norbornene copolymer resin particles, and surfactants.

  The method for molding the image carrier protecting agent of the present invention into a fixed shape, for example, a prismatic or cylindrical shape, is not particularly limited, and a known method can be used as a method for molding a solid substance, For example, a compression molding method, a melt molding method, a powder molding method, a cold isostatic pressing method (CIP), a hot isostatic pressing method (HIP) and the like can be mentioned. Among these, the compression molding method is preferable from the viewpoint of easy cutting of the molded body.

  As the compression molding method, for example, a mixture of the fatty acid metal salt and the inorganic lubricant is placed in a mold of a predetermined size, and then compression molded at a predetermined pressure and time. Examples include a method of removing a product from a mold and obtaining a molded body. Thereafter, the shape of the image carrier protecting agent can be adjusted by cutting or the like.

As the melt molding method, for example, a predetermined amount of a heated and melted fatty acid metal salt and an inorganic lubricant is poured into a mold having a predetermined shape, which is heated to a temperature higher than the melting temperature of the image carrier protecting agent. Accordingly, a method of obtaining a molded body by maintaining at a temperature equal to or higher than the melting point for a certain period of time and then cooling by standing or cooling is exemplified. In addition, in order to remove internal distortion of the molded body, after cooling proceeds to a temperature lower than the phase transition temperature of the fatty acid metal salt and the inorganic lubricant during the cooling, it is gradually restarted again to a temperature equal to or higher than the phase transition temperature. You may heat.
After cooling to a temperature close to room temperature, the molded body is removed from the mold to obtain a molded body of the image carrier protecting agent. After that, the shape of the image carrier protecting agent may be adjusted by cutting or the like.

The mold is preferably a metal mold such as steel, stainless steel or aluminum from the viewpoint of good thermal conductivity and good dimensional accuracy. The inner wall surface of the mold is preferably coated with a release agent such as a fluororesin or a silicone resin in order to improve the releasability.
The produced block-shaped image carrier protecting agent can be used by being bonded to a base material such as metal, alloy, plastic, etc. with an adhesive or the like.

The density of the image-bearing member protecting agent of the present invention is not particularly limited, as appropriate may be selected, 1.11 g / cm ³ or more 1.27 g / cm ³ or less are preferred according to the purpose, 1.11 g / cm ³ or more 1.190 g / cm ³ and more preferably less, 1.116 g / cm ³ or more 1.180 g / cm ³ or less is particularly preferred.
The density of the compression-molded image carrier protective agent is not particularly limited and may be appropriately selected depending on the intended purpose. However, when compression molding is performed at a pressure of 130 kN and a compression time of 10 seconds, 1.11 g / cm ³ or 1.190 g / cm ³ or less is preferable, 1.116 g / cm ³ or more 1.180 g / cm ³ or less is more preferable. Applying said density is, if it is 1.11 g / cm ³ or more 1.190 g / cm ³ or less, the image-bearing member protecting agent supplying member, in particular by using a urethane roller, easily image-bearing member protecting agent to the image bearing member can do.
The density can be calculated by dividing the mass (W) of the image carrier protective agent by the volume (V) of the image carrier protective agent. The mass (W) can be calculated using an analytical balance (device name: AB204-S, manufactured by METTLER TOLEDO CO., LTD.), And the volume (V) can be calculated using a micrometer or a caliper.

(Protective layer forming device)
The protective layer forming apparatus of the present invention has the image carrier protective agent of the present invention and an image carrier protective agent supply member, preferably a protective layer forming member, and further, if necessary, a pressing force is applied. It has other members, such as a member.

As the image carrier protecting agent, the image carrier protecting agent of the present invention is used.
The image carrier protecting agent supply member is a member that supplies the image carrier protecting agent to the surface of the image carrier.
The protective layer forming member is a member that forms a protective layer on the surface of the image carrier by pressing the image carrier protective agent supplied to the image carrier.
The pressing force applying member is a member that presses the image carrier protecting agent and presses it against the image carrier protecting agent supply member.

  In the case where the protective layer forming member is provided in the protective layer forming apparatus, the protective layer forming member may also serve as a cleaning unit. However, in order to more reliably form the protective layer, an image carrier is previously formed by the cleaning unit. It is preferable to remove the residue mainly composed of the toner above so that the residue does not enter the protective layer.

Here, FIG. 3 is a schematic view showing an example of the protective layer forming apparatus of the present invention.
The protective layer forming apparatus 2 disposed opposite to the photosensitive drum as the image carrier 1 includes the image carrier protective agent 21, the image carrier protective agent supply member 22, the pressing force applying member 23, and the protection of the present invention. The layer forming member 24 is configured.

The image carrier protecting agent 21 of the present invention contacts the image carrier protecting agent supply member 22 such as a foam roller by the pressing force from the pressing force applying member 23. The image carrier protecting agent supply member 22 rotates and rubs with the image carrier 1 with a linear velocity difference. At this time, the image carrier protecting agent 21 held on the surface of the image carrier protecting agent supply member 22 is imaged. Supply to the surface of the carrier 1.
Since the image carrier protecting agent 21 supplied to the surface of the image carrier 1 may not be a sufficient protective layer at the time of supply depending on the selection of the material type, in order to form a more uniform protective layer, for example, The protective layer forming member 24 is thinned to form a protective layer.

  The image bearing member on which the protective layer is formed is, for example, in a minute gap by bringing the charging roller 3 to which a DC voltage or a voltage obtained by superimposing an AC voltage is applied with a high voltage power source (not shown) into contact or in proximity. The image carrier 1 is charged by discharging. At that time, a part of the protective layer is decomposed or oxidized by electrical stress. In addition, the air discharge product adheres to the surface of the protective layer.

  The deteriorated image carrier protecting agent is removed by the cleaning unit together with other components such as toner remaining on the image carrier 1 by a normal cleaning unit. Such a cleaning means 4 may be used also as the protective layer forming member 24. However, the function of removing the residue on the surface of the image carrier and the function of forming the protective layer are different from each other. Since the states may be different, the functions are separated, and a cleaning unit 4 including a cleaning member 41 and a cleaning member pressing mechanism 42 is provided upstream of the image carrier protecting agent supply unit 22 as shown in FIG. It is preferable.

  There is no restriction | limiting in particular as a material of the braid | blade used for the said protective layer formation member 24, According to the objective, it can select suitably, For example, urethane rubber, hydrin rubber, silicone rubber, fluororubber etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. In these rubber blades, the contact portion with the image carrier may be coated or impregnated with a low friction coefficient material. Moreover, in order to adjust the density of an elastic body, you may disperse fillers, such as an organic filler and an inorganic filler.

The blade is fixed to the blade support by any method such as adhesion or fusion so that the tip can be pressed against the surface of the image carrier. The thickness of the blade is not particularly limited, and varies depending on the balance with the force applied by pressing and cannot be uniquely defined, but is preferably 0.5 mm or more and 5 mm or less, more preferably 1 mm or more and 3 mm or less.
Also, the length of the cleaning blade that protrudes from the blade support and can bend, that is, the so-called free length, is not unambiguously defined in consideration of the force applied by pressing in the same manner. Is preferably 2 mm or more and 10 mm or less.

  As another configuration of the blade, a coating layer is formed on the surface of an elastic metal blade such as a spring plate by a method such as coating or dipping via a coupling agent or a primer component as necessary, and if necessary, heat is applied. Curing or the like may be performed, and surface polishing or the like may be performed as necessary.

The coating layer contains at least a binder resin and a filler, and further contains other components as necessary.
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include fluorine resins such as PFA, PTFE, FEP and PVDF; silicone elastomers such as fluorine rubber and methylphenyl silicone elastomer. Etc.

  There is no restriction | limiting in particular as thickness of the said elastic metal braid | blade, Although it can select suitably according to the objective, 0.05 mm or more and 3 mm or less are preferable, and 0.1 mm or more and 1 mm or less are more preferable. In the elastic metal blade, in order to suppress twisting of the metal blade, a process such as bending may be performed in a direction substantially parallel to the support shaft after attachment.

  The force that presses the image carrier 1 with the protective layer forming member 24 is sufficient as the force that the image carrier protective agent extends to become a protective layer or a protective film, and there is no particular limitation on the linear pressure. Although it can be appropriately selected according to the purpose, it is preferably 5 gf / cm or more and 80 gf / cm or less, more preferably 10 gf / cm or more and 60 gf / cm or less.

  Examples of the image carrier protecting agent supply member 22 include a brush-like member and a foam roller. Among these, a foam roller is preferable.

-Foam roller-
The foam roller has at least a core material and a foam layer formed on the outer periphery of the core material and having a plurality of bubbles, and further includes other members as necessary.

--- Core material--
There is no restriction | limiting in particular as a material of the said core material, a shape, a magnitude | size, and a structure, According to the objective, it can select suitably.
Examples of the material of the core material include resins such as epoxy resins and phenol resins; metals such as iron, aluminum, and stainless steel.
Examples of the shape of the core material include a columnar shape and a cylindrical shape.
Moreover, you may provide an contact bonding layer on the core metal surface.

-Foam layer-
The foam layer is a layer formed on the outer periphery of the core material, and has a plurality of bubbles (sometimes referred to as “cell”, “hole”, “void”, etc.).
There is no restriction | limiting in particular as a shape of the said foam layer, According to the objective, it can select suitably, For example, cylindrical shape etc. are mentioned.
There is no restriction | limiting in particular as a material of the said foam layer, According to the objective, it can select suitably, For example, foaming polyurethane etc. are mentioned.

  As the image carrier protecting agent supply member, a conventional brush-like member as described in JP 2010-39304 A can be used. However, the foam roller includes a brush-like member and In comparison, since the image carrier protecting agent can be uniformly supplied onto the image carrier, the protection of the image carrier can be improved. Further, it is possible to solve the problem that the shaving amount of the image carrier protecting agent changes due to the sag of the brush over time when a brush-like member is used.

  There is no restriction | limiting in particular as said foaming polyurethane, According to the objective, a well-known manufacturing method can be selected suitably. Examples of the raw material for the foamed polyurethane include polyols, polyisocyanates, catalysts, foaming agents, foam stabilizers, and the like.

--- Polyol ---
There is no restriction | limiting in particular as said polyol, According to the objective, it can select suitably from conventionally well-known various polyols, For example, polyether polyol, polyester polyol, etc. are mentioned. Among these, polyether polyol is preferable from the viewpoint of easy adjustment of processability and foam layer hardness.

As the polyether polyol, for example, at least one of a low molecular polyol and a low molecular polyamine having 2 to 8 active hydrogen groups is used as an initiator, and at least one of ethylene oxide and propylene oxide is opened. Examples include polyether polyols obtained by cycloaddition polymerization.
Examples of the polyether polyol include polyether polyether polyols, polyester polyether polyols, and polymer polyether polyols that are generally used in the production of flexible polyurethane foams.
The polyether polyol is preferably a polyether polyether polyol in which ethylene oxide is bonded to the terminal at 5 mol% or more from the viewpoint of moldability.

Examples of the polyester polyol include dibasic acids such as adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, and maleic anhydride, and anhydrides thereof, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, Examples thereof include polyester polyols obtained by polymerizing glycols and triols such as propylene glycol, 1,4-butanediol, glycerin and trimethylolpropane.
Further, as the polyester polyol, those obtained by depolymerizing a waste material of polyethylene terephthalate resin with the above-mentioned glycol can also be used.
The said polyol may be used individually by 1 type, and may use 2 or more types together.

--- Polyisocyanate ---
There is no restriction | limiting in particular as said polyisocyanate, According to the objective, it can select suitably from conventionally well-known various polyisocyanate, For example, 2, 4- tolylene diisocyanate (2, 4-TDI), 2 , 6-tolylene diisocyanate (2,6-TDI), tolidine diisocyanate (TODI), naphthylene diisocyanate (NDI), xylylene diisocyanate (XDI), 4,4'-diphenylmethane diisocyanate (MDI), carbodiimide-modified MDI, poly Examples include methylene polyphenyl polyisocyanate and polymeric polyisocyanate. These may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as content of the said polyisocyanate, According to the objective, it can select suitably, For example, as an equivalent ratio (NCO / OH) of the isocyanate group of the said polyisocyanate with respect to the hydroxyl group of the said polyol, 1. The range of 0 or more and 3.0 or less is mentioned.

---- Catalyst ---
There is no restriction | limiting in particular as said catalyst, According to the objective, it can select suitably from the catalysts used for a conventionally well-known urethanation reaction, For example, an amine catalyst, an organometallic catalyst, etc. are mentioned. .
Examples of the amine catalyst include triethylenediamine, dimethylethanolamine, and bis (dimethylamino) ethyl ether.
Examples of the organometallic catalyst include dioctyltin and distearyltin dibutyrate.
The catalyst may be a reactive catalyst such as dimethylaminoethanol having active hydrogen.
These may be used individually by 1 type and may use 2 or more types together.

There is no restriction | limiting in particular as content of the said catalyst, According to the objective, it can select suitably, For example, 0.01 mass part or more and 20 mass parts or less are mentioned with respect to 100 mass parts of said polyols.
By appropriately selecting the type of the catalyst and controlling the amount of the catalyst used, it is possible to adjust the cell wall width, open cell diameter, hardness, air flow rate, and the like of the foam layer.

---- Foaming agent ---
There is no restriction | limiting in particular as said foaming agent, According to the objective, it can select suitably, For example, water, a fluorocarbon compound, a low boiling point hydrocarbon type compound etc. are mentioned. These may be used alone or in combination of two or more. Among these, water is preferable from the viewpoint of the environment.
Examples of the fluorocarbon compounds include HCFC-141b, HFC-134a, HFC-245fa, HFC-365mfc, and the like.
Examples of the low-boiling hydrocarbon compound include cyclopentane, n-pentane, iso-pentane, and n-butane.

There is no restriction | limiting in particular as content of the said foaming agent, According to the objective, it can select suitably, For example, 5 mass parts or more and 50 mass parts or less are mentioned with respect to 100 mass parts of said polyols.
By appropriately selecting the type of the foaming agent and controlling the amount of the foaming agent used, the cell wall width, the open cell diameter, the hardness, the air flow rate, and the like of the foam layer can be adjusted.

---- Foam stabilizer ---
There is no restriction | limiting in particular as said foam stabilizer, According to the objective, it can select suitably, For example, silicone type surfactant etc. are mentioned.
As the silicone-based surfactant, a commercially available product can be used. Examples of the commercially-available product include a dimethylsiloxane foam stabilizer (for example, “SRX-253” manufactured by Toray Dow Corning Silicone, Shin-Etsu Chemical Co., Ltd.). "F-122" manufactured by Kogyo Co., Ltd.), polyether-modified dimethylsiloxane foam stabilizers (for example, "L-5309", "SZ-1311" manufactured by Nippon Unicar Co., Ltd.) and the like. These may be used alone or in combination of two or more.
There is no restriction | limiting in particular as content of the said foam stabilizer, According to the objective, it can select suitably, For example, 0.2 mass part or more and 10 mass parts or less etc. are mentioned with respect to 100 mass parts of said polyols. It is done.

--- Other ingredients ---
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a crosslinking agent, a foam breaker, an electrically conductive agent, an antistatic agent, a flame retardant, a viscosity reducing agent, a pigment, a stabilizer , Coloring agents, anti-aging agents, ultraviolet absorbers, antioxidants and the like. These may be used alone or in combination of two or more.

The said crosslinking agent and the said foam breaker are mix | blended in order to control the closed-cell property of the bubble of the said foam layer, and open-cell property.
There is no restriction | limiting in particular as said crosslinking agent, Although it can select suitably according to the objective, Triethanolamine, diethanolamine, etc. are mentioned.
There is no restriction | limiting in particular as said foam breaker, According to the objective, it can select suitably, For example, the thing with high foam breakability is mentioned in the said foam stabilizer.
There is no restriction | limiting in particular as a compounding quantity of the said crosslinking agent and the said foam breaker, According to the objective, it can select suitably.

  Usually, components other than the polyisocyanate are mixed in advance and mixed with the polyisocyanate component immediately before molding.

  A commercially available product can be used as the polyurethane foam. Examples of the commercially available products include HR20, HR30, QM60, QZK50, and QZK70 (all manufactured by Bridgestone Kasei Co., Ltd.).

  There is no restriction | limiting in particular as a structure of the said foam layer, According to the objective, it can select suitably, For example, a closed cell type, an open cell type, these mixed types etc. are mentioned.

  FIG. 1A is a schematic cross-section showing an example of the open-cell foam layer. The open cell foam layer is a foam layer in which adjacent bubbles are connected to each other. Therefore, the foam layer has a structure that allows air and water to pass through. FIG. 1B is a schematic cross section showing an example of the closed cell foam layer. The closed cell foam layer is a foam layer having a structure in which bubbles are independent and air and water are not allowed to pass through.

  Among these, the foam layer is preferable in that the open-cell type has a small compressive residual strain and is easy to return to its original shape even when compressed, so that it hardly deforms even in long-term use. In addition, the open cell type is less costly than the closed cell type, and is advantageous in terms of cost. Since the image carrier can be sufficiently protected, filming of the image carrier can be prevented, a smaller protective agent block can be obtained, and the apparatus can be downsized.

The average cell diameter of the foam roller is not particularly limited as long as it is equal to or smaller than the number-based median diameter (D ₅₀ ) of the image carrier protective agent, and the grinding performance with respect to the image carrier protective agent and the image carrier protective agent are imaged. The average cell diameter is preferably 400 μm or more and 850 μm or less, more preferably 500 μm or more and 700 μm or less from the viewpoint of supplying uniformly to the surface of the carrier. When the average cell diameter is 400 μm or more, it becomes easy to grind the image carrier protective agent, and when the molded body on the block is used as the image carrier protective agent, the supply amount of the image carrier protective agent is stable. Prone. On the other hand, when the average cell diameter is 850 μm or less, the contact area between the image carrier protecting agent and the image carrier is partially increased, so that it is easy to uniformly supply the image carrier protecting agent. .

The average cell diameter of the foam roller can be obtained, for example, from a value obtained by dividing 1 inch (= 25.4 mm) by the number of cells measured by the following method.
On the surface of the foam layer 80 of the foam roller 22, three measurement points are arbitrarily selected between the axial end portions and the central portion (here, in FIG. 2A, 70 is the end measurement portion, and 71 is the center). Part of measurement.). Next, two more points are selected in the circumferential direction at each measurement point, and a total of nine measurement points are determined. Next, the photograph screen of each measurement location is observed using a microscope. Then, as shown in FIG. 2B, a line X having a length corresponding to the actual size d (1 inch) is drawn at the center of the photo screen, and the number of cells in the line is counted. Find the average value. A cell that touches even a d (1 inch) line is counted as one. For example, in the case shown in FIG. 2B, since the number of cells is 12, the average cell diameter is 25.4 (mm) ÷ 12 (cells) = 2.117 (mm) = 2,117 (μm). .

There is no restriction | limiting in particular as average thickness of the said foam layer, Although it can select suitably according to the objective, 1 mm or more and 4 mm or less are preferable. If the average thickness is 1 mm or more, it is difficult to pick up the influence of the shaft (core material), and if it is 4 mm or less, it is possible to prevent the image carrier protecting agent from being scraped off.
When the foam layer is cylindrical, the thickness is defined as the distance between the cylindrical inner peripheral surface and the outer peripheral surface. Here, the average thickness is an average value when the thickness of the foam layer is arbitrarily measured at three points.

There is no restriction | limiting in particular as hardness of the said foam layer, Although it can select suitably according to the objective, 40N or more and 430N or less are preferable, and 40N or more and 300N or less are more preferable. When the hardness is 40 N or more, the image carrier can be prevented from being contaminated. When the hardness is 430 N or less, the image carrier can be prevented from being contaminated. When the hardness is in the more preferable range, it is advantageous in that the suppression of contamination of the image carrier is more excellent.
The hardness is an average value of values measured based on JIS K 6400 at arbitrary three points on the surface of the foam layer.

  In the foam layer, the form of the bubbles (open-cell type or closed-cell type), the number of the bubbles, the hardness of the foam layer, and the like are the types of the polyurethane foam raw material when producing the foam layer, It can be controlled by appropriately adjusting the amount of the foaming agent, reaction conditions, and the like.

[Method for Manufacturing Image Carrier Protecting Agent Supply Member]
There is no restriction | limiting in particular as a manufacturing method of the said image carrier protection agent supply member, According to the objective, it can select suitably.
As an example of the manufacturing method of the image carrier protecting agent supply member, a manufacturing example in the case where the foamed polyurethane is used as the material of the foam layer will be described.
First, a foamed polyurethane raw material is foam-cured by a known method to form a block-shaped foamed polyurethane. Then, after cutting into a required shape, polishing the surface, processing into a cylindrical shape having bubbles opened on the surface, the core material is inserted into the cylindrical shape. Thereafter, a polishing blade or the like is applied while rotating the polyurethane foam using a polishing machine and a cutting machine, and the blade is moved parallel to the axial direction of the image carrier protecting agent supply member to cut to a predetermined thickness (traverse grinding). ). Thereby, a cylindrical image carrier protecting agent supply member having bubbles opened on the surface is obtained. Furthermore, irregular irregularities can be formed on the surface of the foam layer by changing the rotation speed or the moving speed of the image carrier protective agent supply member.
An adhesive may be applied to the core material in order to improve the adhesiveness with the foam layer. Through these steps, the image carrier protecting agent supply member is manufactured.

Another example of the method for manufacturing the image carrier protecting agent supply member will also be described.
A foamed polyurethane raw material is injected into a molding die for molding the image carrier protecting agent supply member containing the core material, and foamed and cured. Thereby, the image carrier protecting agent supply member is manufactured.

Among these production methods, the method using a mold is preferable because the formation of the foam layer and the surface thereof can be simultaneously opened, and the processing accuracy is good.
The manufacturing method using the mold does not require complicated processing, and the foam layer having a suitable opening property can be formed. Therefore, the inner surface of the mold is separated by a fluororesin coating agent, a release agent, or the like. It is preferable to provide a mold layer.

(Image forming method and image forming apparatus)
The image forming method of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a protective layer forming step, and other steps appropriately selected as necessary, for example, a fixing step, It includes a cleaning process, a static elimination process, a recycling process, a control process, and the like.
The image forming apparatus according to the present invention includes at least an image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a protective layer forming unit, and other components appropriately selected as necessary. For example, a cleaning means, a fixing means, a charge eliminating means, a recycling means, a control means and the like.

  The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming means, and the developing step is the developing The transfer step can be performed by the transfer unit, the protective layer forming step can be performed by the protective layer forming unit, and the other steps can be performed by the other unit. it can.

<Image carrier>
There is no restriction | limiting in particular as said image carrier, According to the objective, it can select suitably, For example, the image carrier etc. which were described in Paragraph [0049]-[0084] of Unexamined-Japanese-Patent No. 2014-142538 etc. Can be mentioned.

<Electrostatic latent image forming step and electrostatic latent image forming means>
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the image carrier, and can be performed by an electrostatic latent image forming unit.

  Next, the formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the image carrier and then exposing the image like the image, and is performed by the electrostatic latent image forming unit. be able to. The electrostatic latent image forming unit includes, for example, at least a charger that uniformly charges the surface of the image carrier and an exposure unit that exposes the surface of the image carrier imagewise.

The charging can be performed, for example, by applying a voltage to the surface of the image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers using corona discharge such as corotrons, corotrons and scorotrons.
The charger preferably has voltage applying means for applying a voltage having an AC component.

The exposure can be performed, for example, by exposing the surface of the image carrier imagewise using the exposure device.
The exposure device is not particularly limited as long as it can be exposed like an image to be formed on the surface of the image carrier charged by the charger, and can be appropriately selected according to the purpose. Examples thereof include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing unit is not particularly limited as long as it can be developed using, for example, the toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated, A preferable example is one having at least a developing unit capable of applying the toner or the developer to the electrostatic latent image in a contact or non-contact manner.

<< Toner >>
There is no restriction | limiting in particular as said toner, According to the objective, it can select suitably, For example, the toner etc. of Paragraph [0089]-[0179] of Unexamined-Japanese-Patent No. 2014-142538 are mentioned.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multicolor developing unit. For example, a toner having a stirrer that charges the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

In the developing unit, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted to the image carrier. Move to the surface. As a result, the electrostatic latent image is developed with the toner to form a visible image with the toner on the surface of the image carrier.
The developer accommodated in the developing device is a developer containing the toner, but the developer may be a one-component developer or a two-component developer.

<Transfer process and transfer means>
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the image carrier with the visible image using a transfer charger, and can be performed by the transfer unit. The transfer unit includes a primary transfer unit that transfers a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer unit that transfers the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and can be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

  The image carrier is used to perform image transfer by a so-called intermediate transfer method in which a toner image formed on the image carrier is primarily transferred to perform color superposition and then transferred to a recording medium. It may be a body.

<< Intermediate transfer body >>
There is no restriction | limiting in particular as said intermediate transfer body, According to the objective, it can select suitably, For example, the intermediate transfer body as described in Paragraph [0184]-[0185] of Unexamined-Japanese-Patent No. 2014-142538 etc. are mentioned. It is done.

The transfer unit (the primary transfer unit and the secondary transfer unit) preferably includes at least a transfer unit that peels and charges the visible image formed on the image carrier to the recording medium side. . There may be one transfer means or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

<Protective layer forming step and protective layer forming means>
The protective layer forming step is a step of forming a protective layer by applying the image carrier protecting agent of the present invention to the surface of the image carrier after transferring the visible image.
The protective layer forming means is a means for forming the protective layer by applying the image carrier protective agent of the present invention to the surface of the image carrier after transferring the visible image.

<Other processes and other means>
Examples of the other processes include a fixing process, a cleaning process, a static elimination process, a recycling process, and a control process.
Examples of the other means include a fixing means, a cleaning means, a static elimination means, a recycling means, and a control means.

<< Fixing process and fixing means >>
The fixing step is a step of fixing the visible image transferred to the recording medium using the fixing unit, and may be performed each time the toner of each color is transferred to the recording medium, or may be applied to the toner of each color. On the other hand, it may be carried out simultaneously at the same time in a state of being laminated.
The fixing unit is not particularly limited and may be appropriately selected depending on the intended purpose, but a known heating and pressing unit is preferable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller, and an endless belt.
There is no restriction | limiting in particular in the heating in the said heating-pressing means, Although it can select suitably according to the objective, 80 to 200 degreeC is preferable.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

<< Cleaning process and cleaning means >>
The cleaning step is a step of removing the toner remaining on the image carrier and can be suitably performed by a cleaning unit.
The cleaning unit is preferably provided downstream of the transfer unit and upstream of the protective layer forming unit.
The cleaning means is not particularly limited as long as the toner remaining on the image carrier can be removed, and can be selected as appropriate. For example, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade Examples include cleaners, brush cleaners, and web cleaners.

<< Static elimination process and static elimination means >>
The neutralization step is a step of performing neutralization by applying a neutralization bias to the image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the image carrier. For example, a neutralization lamp or the like is preferable. It is done.

<< Recycling process and recycling means >>
The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, According to the objective, it can select suitably, For example, a well-known conveyance means etc. are mentioned.

<< Control process and control means >>
The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

Here, FIG. 4 is a cross-sectional view showing an example of the image forming apparatus 100 having the protective layer forming apparatus of the present invention.
Around the drum-shaped image carriers 1Y, 1M, 1C, and 1K, a protective layer forming device 2, a charging unit 3, an exposure unit 8, a developing unit 5, a transfer unit 6, and a cleaning unit 4 are arranged, respectively. Image formation is performed by operation. Y represents yellow, M represents magenta, C represents cyan, and K represents black.

Next, a series of processes for image formation will be described using a negative-positive process.
An image carrier represented by an organic photoconductor (OPC) having an organic photoconductive layer is neutralized by a neutralizing lamp (not shown) or the like, and is uniformly negatively charged by the charging means 3.
When the image carrier is charged by the charging unit 3, the image carrier 1Y, 1M, 1C, 1K is suitable for charging the image carrier 1Y, 1M, 1C, 1K to a desired potential from a voltage application mechanism (not shown). A voltage having an appropriate magnitude or a charging voltage obtained by superimposing an AC voltage thereon is applied.
The charged image carriers 1Y, 1M, 1C, and 1K form a latent image with laser light irradiated by the exposure means 8 such as a laser optical system (the absolute value of the exposed portion potential is greater than the absolute value of the non-exposed portion potential). Low potential).
Laser light is emitted from a semiconductor laser, and the surfaces of the image carriers 1Y, 1M, 1C, and 1K are scanned in the direction of the rotation axis of the image carrier by a polygonal polygonal mirror (polygon) that rotates at high speed.
The latent image formed in this way is developed with the toner supplied on the developing sleeve, which is a developer carrying member in the developing means 5, or with the developer composed of toner and carrier, and a toner image is formed. The
At the time of developing the electrostatic latent image, a voltage of an appropriate magnitude is present between the exposed portion and the non-exposed portion of the image carrier 1Y, 1M, 1C, 1K from the voltage application mechanism (not shown) to the developing sleeve. Alternatively, a developing bias in which an AC voltage is superimposed on this is applied.

The toner images formed on the image carriers 1Y, 1M, 1C, and 1K corresponding to the respective colors are transferred onto the intermediate transfer body 60 by the transfer unit 6 and fed from the paper supply unit 200, such as paper. A toner image is transferred onto the recording medium.
At this time, it is preferable that a potential having a polarity opposite to the polarity of toner charging is applied to the transfer unit 6 as a transfer bias. Thereafter, the intermediate transfer member 60 is separated from the image carrier to obtain a transfer image.
In addition, the toner remaining on the image carrier is collected by the cleaning unit 4 in the toner collecting chamber in the cleaning unit 4.

  As the image forming apparatus, a plurality of the developing units are used, and a plurality of toner images of different colors sequentially produced by the plurality of developing units are sequentially transferred onto a recording medium, and then sent to a fixing unit, where Even after a plurality of toner images prepared in the same manner are sequentially transferred onto an intermediate transfer member, and then transferred to a recording medium such as paper, Similarly, a fixing means may be used.

The charging means 3 is preferably a charging means disposed in contact with or close to the surface of the image carrier. As the charging means, a discharge wire is used. As a result, the amount of ozone generated during charging can be greatly suppressed as compared with corona dischargers such as so-called corotrons and scorotrons.
In the charging means for charging in contact with or close to the surface of the image carrier, as described above, the discharge is performed in the region near the surface of the image carrier, so that the electrical stress on the image carrier tends to increase. It is. However, by using the protective layer forming apparatus using the image carrier protecting agent of the present invention, the image carrier can be maintained for a long time without deteriorating, so that stable image quality can be ensured.

<Process cartridge>
The process cartridge of the present invention comprises at least an image carrier and the protective layer forming means of the present invention, and further, charging means, exposure means, developing means, transfer means, cleaning means, charge eliminating means as necessary. And other means.
The process cartridge can be detachably mounted on various electrophotographic image forming apparatuses, and is preferably detachably mounted on the image forming apparatus of the present invention.

Here, FIG. 5 is a schematic view showing an example of the process cartridge of the present invention.
The process cartridge includes a protective layer forming device 2, an image carrier protective agent 21, an image carrier protective agent supply member 22, a pressing force applying member 23, which are disposed to face a photosensitive drum as the image carrier 1. The protective layer forming member 24 is configured.
Further, the image carrier 1 has a surface on which the image carrier protective agent or toner partially deteriorated after the transfer process remains, but the surface residue is cleaned and cleaned by the cleaning unit 4.
In FIG. 5, the cleaning unit 4 is provided upstream of the image carrier protecting agent supply unit, and includes a cleaning member 41 and a cleaning pressing mechanism 42, and is brought into contact with an angle similar to a so-called counter type (leading type). ing.
The image carrier protective agent 21 is supplied from the image carrier protective agent supply member 22 to the surface of the image carrier 1 from which the residual toner and the deteriorated image carrier protective agent on the surface have been removed by the cleaning unit 4. A film-like protective layer is formed by the layer forming member 24. At this time, the image carrier protecting agent 21 of the present invention has a better adsorptivity to the portion of the surface of the image carrier that is highly hydrophilic due to electrical stress. Even if a stress is applied and the surface of the image carrier starts to deteriorate partially, the image carrier itself can be prevented from progressing by adsorption of the protective agent.
The image carrier 1 on which the film-like protective layer is formed in this way is charged by the charging means 3, and then an electrostatic latent image is formed by exposure L such as a laser, and developed by the developing means 5 to be a visible image. And transferred to the recording medium 7 by the transfer means 6 outside the process cartridge.

  According to the image forming apparatus and the process cartridge of the present invention, it is possible to prevent wear and filming of the image carrier, contamination of the charging unit, and toner slippage in the cleaning process, so that an extremely high quality image can be obtained over a long period of time. It can be formed stably.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

  The tap density of the inorganic lubricant used in the following examples and comparative examples was measured as follows.

[Measurement of tap density of inorganic lubricant]
The tap density of the inorganic lubricant was measured using a powder characteristic evaluation device (Powder Tester (registered trademark) PT-X (manufactured by Hosokawa Micron Corporation)) according to the Japanese Pharmacopoeia.

Example 1
-Production of image carrier protective agent-
80 parts by mass of zinc stearate as a fatty acid metal salt (manufactured by Wako Pure Chemical Industries, Ltd.) and boron nitride B as an inorganic lubricant (trade name: HP-2W, manufactured by Mizushima Alloy Iron Co., Ltd., tap density: 0. 3 g / cm ³ ) A mixture of 20 parts by mass was placed in a mold of a predetermined size and then leveled, and then compression molded with a pressure of 130 kN and a compression time of 10 seconds. After cooling, the solid was removed from the mold and 10 mm × 21 mm × It was cut to a size of 300 mm and attached to a metal support with a double-sided tape to produce an image carrier protecting agent. The density of the produced image carrier protective agent was calculated by dividing the mass (W) of the image carrier protective agent by the volume (V) of the image carrier protective agent. The mass (W) was calculated using an analytical balance (device name: AB204-S, manufactured by METTLER TOLEDO Co., Ltd.), and the volume (V) was calculated using a micrometer. As a result, the density was 1.18 g / cm ³ .

<Image formation>
An image carrier protecting agent was applied to an image carrier as an image carrier using an apparatus obtained by modifying the image forming apparatus (image MPC4500, manufactured by Ricoh Co., Ltd.) shown in FIG. 4 as follows. That is, in the image forming unit of the image forming apparatus (image MP C4500, manufactured by Ricoh Co., Ltd.), an image carrier used in the image forming apparatus (product equipped with imgio MP C4500) was used as an image carrier. The image carrier protecting agent used in the image forming apparatus was replaced with the produced image carrier protecting agent of Example 1. A urethane roller was used as an image carrier protecting agent supply member used in the image forming apparatus. The urethane roller has a metal core having an outer diameter of 6 mm and a length of 365 mm, on which an open-cell foam layer made of polyurethane is formed so that the outer diameter is 12 mm (Co., Ltd.) (Manufactured by Bridgestone), the number of cells is 60, and the cell diameter of the open cell is 420 μm. In addition, a toner used in the image forming apparatus (a product equipped with imagio MP C4500) was used as the toner.

(Examples 2 to 13 and Comparative Examples 1 to 4)
Example 2 is the same as Example 1 except that the type, content, and protective agent molding method of the fatty acid metal salt and the inorganic lubricant are changed as shown in Tables 1 to 4 in Example 1. To 13 and Comparative Examples 1 to 4 were prepared.
In Example 13, the image formation in Example 1 was performed except that the urethane roller of the image forming apparatus in Example 1 was changed to a brush roller (trade name: SA-7 (acrylic), manufactured by Toray Industries, Inc.). The image forming apparatus in Example 13 was made in the same manner as the apparatus. The density of the produced image carrier protecting agent was measured in the same manner as in Example 1. The results are shown in Tables 1 to 4.

(Examples 14 and 15)
-Production of image carrier protective agent-
80 parts by mass of zinc stearate as a fatty acid metal salt (manufactured by Wako Pure Chemical Industries, Ltd.), boron nitride B as an inorganic lubricant (trade name: HP-2W, manufactured by Mizushima Alloy Iron Co., Ltd., tap density: 0.3 g / Cm ³ ) 20 parts by mass of the mixture is heated and melted, injected into a mold, cooled and solidified, and then the solid is removed from the mold and cut into a size of 10 mm × 21 mm × 300 mm. Then, it was affixed to a metal support with a double-sided tape to produce an image carrier protecting agent.
The image forming apparatus in Example 14 was made in the same manner as the image forming apparatus in Example 1 using the produced image carrier protective agent of Example 14.
In Example 15, the image formation in Example 14 was performed except that the urethane roller of the image forming apparatus in Example 14 was changed to a brush roller (trade name: SA-7 (acrylic), manufactured by Toray Industries, Inc.). The image forming apparatus in Example 15 was made in the same manner as the apparatus.
The density of the image carrier protecting agent produced in Examples 14 and 15 was measured in the same manner as in Example 1. The results are shown in Table 3.

  Next, using the image forming apparatus, the anti-contamination of the charging means, the protection property of the image carrier, the cleaning property, and the moldability of the image carrier protection agent were evaluated as follows. The results are shown in Tables 1 to 4.

<Preventing contamination of charging means>
Using a test chart (A4 size) with an image area ratio of 5%, output 100,000 sheets of images in either a normal temperature environment (23 ° C, 50% RH) or a low temperature environment (10 ° C, 15% RH). The charging means (charging roller) was visually observed, and the prevention of contamination of the charging means was evaluated based on the following criteria.
〔Evaluation criteria〕
A: The charging unit is hardly soiled. B: The charging unit is slightly soiled, but there is no effect on the image in a normal temperature environment (23 ° C., 50% RH). Δ: The charging unit is dirty, and the low temperature environment (10 ° C., 15% RH). An abnormal image (image that appears as black streaks on the image) is generated. ×: The charging means is very dirty, and the abnormal image (image is about 5,000) in a low temperature environment (10 ° C., 15% RH). (Images that appear as black lines)

<Protection of image carrier>
Using a test chart (A4 size) with an image area ratio of 5%, 100,000 images were output in a normal temperature environment (23 ° C., 50% RH), the image carrier was visually observed, and an image was obtained based on the following criteria. The protective property of the support was evaluated.
〔Evaluation criteria〕
A: There is almost no wear and filming on the image carrier. ○: There is a slight filming on the image carrier, but an acceptable level. Δ: There is filming on the image carrier, and it is abnormal over time (about 20,000 sheets). An image (image that appears as white streaks on the image) occurs ×: The image carrier has filming, and an abnormal image (image that appears as white streaks on the image) occurs early (approximately 5,000 images) Do

<Cleanability>
After running 500 sheets (passing paper), it is replaced with a new image carrier, and a linear sponge tape (Scotch tape 4016, with an average thickness of 2 mm) is formed downstream of the cleaning blade and at the upper end of the opening of the developing means. “Through-through toner catcher” (average thickness: 1 mm, felt of 8 mm × 310 mm, manufactured by Ashiya Co., Ltd.) was used. After 100 runs (passing) using a chart with an image area ratio of 5%, the toner slipped downstream of the cleaning blade during the run (passing) of 20 sheets with an image area ratio of 5% is passed through the “slip-through”. Collected with "toner catcher". The collected toner was converted into digital data by an image scanner, and the black streaks on the image were visually observed to confirm the presence or absence of toner slip, and the cleaning property was evaluated based on the following criteria.
〔Evaluation criteria〕
A: There is almost no toner slipping ○: There is toner slipping, but no abnormal image (image appearing as black streaks on the image) is generated Δ: Toner slipping occurs and abnormal images (black streaks on the image) X: An image that appears as a black streak frequently occurs due to a lot of toner passing through.

<Moldability of image carrier protective agent>
The presence or absence of cracks when 100 image carrier protective agents were produced was observed, the crack generation rate was determined, and the moldability of the image carrier protective agent was evaluated based on the following criteria.
Here, the crack means a partial crack generated in the longitudinal direction of the side surface of the molded article of the image carrier protecting agent.
〔Evaluation criteria〕
A: The image carrier protecting agent is hardly cracked (the crack generation rate is less than 5% by number).
○: Slight cracking occurs in the image carrier protective agent, but is at an acceptable level (the occurrence rate of cracks is 5% or more and less than 10%).
Δ: Image carrier protective agent is liable to crack and yield is poor (crack generation rate is 10% or more and less than 20%)
X: Image carrier protective agent was frequently cracked and difficult to mold (crack generation rate of 20% by number or more)

  Details of the fatty acid metal salts and inorganic lubricants in Tables 1 to 4 are as follows.

-Fatty acid metal salt-
-Zinc stearate: Wako Pure Chemical Industries, Ltd.-Calcium stearate: Wako Pure Chemical Industries, Ltd.-Zinc laurate: Wako Pure Chemical Industries, Ltd.

-Inorganic lubricant-
Boron nitride A: manufactured by Saint-Gobain, PCTP2, tap density: 0.2 g / cm ³
Boron nitride B: manufactured by Mizushima Alloy Iron Co., Ltd., HP-2W, tap density: 0.3 g / cm ³
Boron nitride C: manufactured by Saint-Gobain, PCTP8, tap density: 0.5 g / cm ³
Boron nitride D: manufactured by Saint-Gobain, PCTL30, tap density: 0.6 g / cm ³
Boron nitride E: manufactured by Mizushima Alloy Iron Co., Ltd., HP-1CAW, tap density: 0.8 g / cm ³
Boron nitride F: manufactured by Mizushima Alloy Iron Co., Ltd., HP-40, tap density: 0.9 g / cm ³

(Examples 16 to 25, Examples 28 to 29, and Comparative Examples 5 to 7)
In Example 1, Example 16 was carried out in the same manner as in Example 1 except that the type, content, and protective agent molding method of the fatty acid metal salt and the inorganic lubricant were changed as shown in Tables 5 to 8. To 25, Examples 28 to 29 and Comparative Examples 5 to 7 were prepared. In Example 25, image formation in Example 1 was performed except that the urethane roller of the image forming apparatus in Example 1 was changed to a brush roller (trade name: SA-7 (acrylic), manufactured by Toray Industries, Inc.). In the same manner as the apparatus, the image forming apparatus in Example 25 was obtained. The density of the produced image carrier protecting agent was measured in the same manner as in Example 1. The results are shown in Tables 5-8.

(Example 26)
In Example 14, the image bearing of Example 26 was carried out in the same manner as in Example 14 except that the type, content, and protective agent molding method of the fatty acid metal salt and the inorganic lubricant were changed as shown in Table 7. A body protecting agent was prepared.
The image forming apparatus in Example 26 was prepared in the same manner as the image forming apparatus in Example 14 using the produced image carrier protecting agent of Example 26.

(Example 27)
In Example 26, the image bearing of Example 27 was carried out in the same manner as in Example 26, except that the type, content, and protective agent molding method of the fatty acid metal salt and inorganic lubricant were changed as shown in Table 7. A body protecting agent was prepared.
In Example 26, the image in Example 27 is the same as Example 26 except that the urethane roller of the image forming apparatus is changed to a brush roller (trade name: SA-7 (acrylic), manufactured by Toray Industries, Inc.). A forming apparatus was obtained.

  Next, using the image forming apparatus, in the same manner as in Example 1, the prevention of contamination of the charging means, the protection property of the image carrier, the cleaning property, and the moldability of the image carrier protection agent were evaluated. Further, “blade squeal resistance” was evaluated as follows. The results are shown in Tables 5-8.

<Blade resistance>
Using a test chart (A4 size) with an image area ratio of 5%, under a high temperature environment (32 ° C., 54% RH), the photosensitive member linear velocity is 10,000 sheets at full speed (normal printing speed), and The output of 10,000 sheets was performed at a photosensitive linear speed of half speed (thick paper mode), and “blade squeal resistance” was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
◎: No abnormal noise is generated. ○: At half speed, a slight abnormal noise that cannot be heard unless the ear is brought close to the 1,000 sheets once per 1,000 sheets is an acceptable level. △: At half speed Abnormal noise occurs ×: Abnormal noise occurs at both full speed and half speed

The details of the fatty acid metal salt and the inorganic lubricant in Tables 5 to 8 are as follows.
-Fatty acid metal salt-
-Zinc stearate: Wako Pure Chemical Industries, Ltd.-Calcium stearate: Wako Pure Chemical Industries, Ltd.-Zinc laurate: Wako Pure Chemical Industries, Ltd.

-Inorganic lubricant-
Boron nitride F: manufactured by Momentive Performance Materials Japan, NX1, tap density: 0.12 g / cm ³
Boron nitride A: manufactured by Saint-Gobain, PCTP2, tap density: 0.2 g / cm ³
Boron nitride G: manufactured by Mizushima Alloy Co., Ltd., HP-P1, tap density: 0.25 g / cm ³
-Mica: manufactured by Yamaguchi Mica Co., Ltd., Y-3000, tap density: 0.25 g / cm ³
Boron nitride B: manufactured by Mizushima Alloy Iron Co., Ltd., HP-2W, tap density: 0.3 g / cm ³
Boron nitride H: Mizushima alloy iron, HP-4W, tap density: 0.4 g / cm ³
Boron nitride C: manufactured by Saint-Gobain, PCTP8, tap density: 0.5 g / cm ³
Boron nitride D: manufactured by Saint-Gobain, PCTL30, tap density: 0.6 g / cm ³
Boron nitride E: manufactured by Mizushima Alloy Iron Co., Ltd., HP-1CAW, tap density: 0.8 g / cm ³
Boron nitride I: manufactured by Mizushima Alloy Iron Co., Ltd., HP-40, tap density: 0.9 g / cm ³

As an aspect of this invention, it is as follows, for example.
<1> Contains a fatty acid metal salt and an inorganic lubricant,
An image bearing member protecting agent, wherein the inorganic lubricant contains a first inorganic lubricant having a tap density of 0.30 g / cm ³ or more and 0.8 g / cm ³ or less.
<2> The image carrier protective agent according to <1>, wherein the inorganic lubricant further includes a second inorganic lubricant having a tap density of 0.25 g / cm ³ or less.
<3> The image carrier protecting agent according to <1> to <2>, wherein the first inorganic lubricant is boron nitride.
<4> The second inorganic lubricant is mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, silica, graphite, polymethyl methacrylate resin, polytetrafluoroethylene resin. The image carrier protective agent according to any one of <2> to <3>, which is at least one selected from melamine formaldehyde, organic molybdenum, and silicone resin.
<5> The image carrier protecting agent according to any one of <1> to <4>, wherein the fatty acid metal salt is at least one selected from zinc stearate, calcium stearate, and zinc laurate. .
<6> density, an image bearing member protecting agent according to any one of <5> to 1.11 g / cm ³ or more 1.190 g / cm ³ or less is the <1>.
<7> Mass ratio (fatty acid metal salt / inorganic lubricant) of content (mass%) of the fatty acid metal salt and content (mass%) of the inorganic lubricant is 70/30 or more and 98/2 or less. The image carrier protecting agent according to any one of <1> to <6>, wherein
<8> The image carrier protective agent according to any one of <1> to <7>, which is a compression molded product of a mixture including the fatty acid metal salt and the inorganic lubricant.
<9> The image carrier protecting agent according to any one of <1> to <8>, wherein a tap density of the first inorganic lubricant is 0.30 g / cm ³ or more and 0.7 g / cm ³ or less. It is.
<10> The image carrier protecting agent according to any one of <1> to <9>, wherein the fatty acid metal salt has a lamellar crystal structure.
<11> The image carrier protecting agent according to any one of <1> to <10>, wherein the tap density of the first inorganic lubricant is 0.35 g / cm ³ or more and 0.6 g / cm ³ or less. It is.
<12> The image carrier protective agent according to any one of <1> to <11>, wherein the inorganic lubricant has a number average primary particle size of 0.1 μm to 10 μm.
<13> The image carrier protecting agent according to any one of <1> to <12>, wherein a content of the fatty acid metal salt is 70% by mass or more and 98% by mass or less.
<14> The image carrier protective agent according to any one of <1> to <13>, wherein the content of the inorganic lubricant is 2% by mass or more and 30% by mass or less.
<15> The image carrier protective agent according to any one of <2> to <14>, wherein the tap density of the second inorganic lubricant is 0.2 g / cm ³ or more and 0.25 g / cm ³ or less. It is.
<16> The image carrier protecting agent according to any one of <1> to <15>,
And an image carrier protecting agent supply member that supplies the image carrier protecting agent to the surface of the image carrier.
<17> The protective layer forming apparatus according to <16>, wherein the image carrier protective agent supply member has a foam layer.
<18> The protective layer forming apparatus according to <17>, wherein the foam layer is an open-cell type.
<19> Any of <16> to <18>, further comprising a protective layer forming member that presses the image carrier protective agent supplied to the image carrier to form a protective layer on the surface of the image carrier. A protective layer forming apparatus according to claim 1.
<20> an electrostatic latent image forming step of forming an electrostatic latent image on the image carrier;
A developing step of developing the electrostatic latent image with toner to form a visible image;
A transfer step of transferring the visible image to a recording medium;
A protective layer forming step of forming a protective layer by applying the image carrier protective agent according to any one of <1> to <15> to the surface of the image carrier after transferring the visible image. This is an image forming method.
<21> an image carrier, and electrostatic latent image forming means for forming an electrostatic latent image on the image carrier,
Developing means for developing the electrostatic latent image with toner to form a visible image;
Transfer means for transferring the visible image onto a recording medium;
Protective layer forming means for forming a protective layer by applying the image carrier protective agent according to any one of <1> to <15> to the surface of the image carrier after transferring the visible image; An image forming apparatus including the image forming apparatus.
<22> The image forming apparatus according to <21>, further including a cleaning unit that removes toner remaining on the surface of the image carrier on the downstream side of the transfer unit and the upstream side of the protective layer forming unit. .
<23> an image carrier;
And a protective layer forming means for forming a protective layer by applying the image carrier protective agent according to any one of <1> to <15> to a surface of the image carrier. It is.

  The image carrier protective agent according to any one of <1> to <15>, the protective layer forming apparatus according to <16> to <19>, the image forming method according to <20>, and <21 > To <22> and the process cartridge according to <23> can solve the conventional problems and achieve the object of the present invention.

JP 2009-300861 A JP 2010-39304 A JP 2012-58539 A

DESCRIPTION OF SYMBOLS 1 Image carrier 2 Protection layer formation apparatus 4 Cleaning means 5 Development means 6 Transfer means 7 Recording medium 21 Image carrier protection agent 22 Image carrier protection agent supply member 24 Protection layer formation member

Claims (16)

Containing a fatty acid metal salt and an inorganic lubricant,
An image bearing member protective agent, wherein the inorganic lubricant contains a first inorganic lubricant having a tap density of 0.30 g / cm ³ or more and 0.8 g / cm ³ or less. The image carrier protecting agent according to claim 1, wherein the inorganic lubricant further comprises a second inorganic lubricant having a tap density of 0.25 g / cm ³ or less.   The image carrier protecting agent according to claim 1, wherein the first inorganic lubricant is boron nitride.   The second inorganic lubricant is mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, silica, graphite, polymethyl methacrylate resin, polytetrafluoroethylene resin, melamine formaldehyde The image bearing member protecting agent according to any one of claims 2 to 3, which is at least one selected from the group consisting of organic molybdenum and silicone resin.   The image carrier protecting agent according to any one of claims 1 to 4, wherein the fatty acid metal salt is at least one selected from zinc stearate, calcium stearate, and zinc laurate. Density, image-bearing member protecting agent according to any one of claims 1 to 5 or less 1.11 g / cm ³ or more 1.190 g / cm ^3.   The mass ratio (fatty acid metal salt / inorganic lubricant) between the content (mass%) of the fatty acid metal salt and the content (mass%) of the inorganic lubricant is 70/30 or more and 98/2 or less. Item 7. The image carrier protective agent according to any one of Items 1 to 6.   The image carrier protective agent according to any one of claims 1 to 7, which is a compression molded product of a mixture comprising the fatty acid metal salt and the inorganic lubricant. The image carrier protecting agent according to any one of claims 1 to 8,
An image carrier protecting agent supply member for supplying the image carrier protecting agent to the surface of the image carrier;   The protective layer forming apparatus according to claim 9, wherein the image carrier protective agent supply member has a foam layer.   The protective layer forming apparatus according to claim 10, wherein the foam layer is of an open cell type.   The protective layer according to claim 9, further comprising a protective layer forming member that presses the image carrier protective agent supplied to the image carrier and forms a protective layer on the surface of the image carrier. Forming equipment. An electrostatic latent image forming step of forming an electrostatic latent image on the image carrier;
A developing step of developing the electrostatic latent image with toner to form a visible image;
A transfer step of transferring the visible image to a recording medium;
A protective layer forming step of forming a protective layer by applying the image carrier protective agent according to claim 1 to the surface of the image carrier after transferring the visible image. An image forming method. An image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on the image carrier;
Developing means for developing the electrostatic latent image with toner to form a visible image;
Transfer means for transferring the visible image onto a recording medium;
Protective layer forming means for forming a protective layer by applying the image carrier protective agent according to any one of claims 1 to 8 to the surface of the image carrier after transferring the visible image. An image forming apparatus.   The image forming apparatus according to claim 14, further comprising a cleaning unit that removes toner remaining on the surface of the image carrier on the downstream side of the transfer unit and the upstream side of the protective layer forming unit. An image carrier;
9. A process cartridge comprising: a protective layer forming unit that forms a protective layer by applying the image carrier protective agent according to claim 1 to a surface of the image carrier.