JP5219661B2 - Image forming method - Google Patents

Description

  The present invention relates to an image forming method using electrophotography, electrostatic recording, and magnetic recording. More specifically, the present invention relates to an image forming method used in an image forming apparatus such as a copying machine, a printer, or a fax machine that forms a toner image on a photosensitive member and then transfers the toner image onto a transfer material to form an image.

  Conventionally, many methods are known as electrophotographic methods. In general electrophotography, a photoconductive substance is used to form an electrical latent image on an image carrier (hereinafter also referred to as a photoreceptor) by various means, and then the latent image is developed. The agent (hereinafter also referred to as toner) is transferred to a visible image to obtain a toner image. Further, a method is known in which a toner image is transferred onto a transfer material such as paper as necessary, and then the toner image is fixed on the transfer material by heat / pressure to obtain a copy.

In recent years, with the development of the information industry and increasing environmental awareness, there has been a demand for an image forming apparatus having high image quality, long life, low running cost, and small size and low power for industrial or office use.
In response to these demands, approaches have been made from various aspects of the electrophotographic main body, the photoreceptor, the developer, and various functional members. For example, it has been proposed that a photoconductor is provided with a surface layer having a high hardness, which greatly reduces the amount of shaving and extends the life (Patent Documents 1 to 3).

  However, since the surface hardness of the photoreceptor increases and the amount of scraping decreases, the discharge product tends to be insufficiently removed. As a result, image flow is likely to occur, and the friction on the surface of the photoconductor increases, so that problems such as the squealing and wrinkling of the cleaning member, and the edge of the cleaning member are likely to occur. In order to solve these problems, it has been suggested that it is effective to roughen the surface of the photoreceptor by applying surface processing such as streaks or dimples to the surface of the photoreceptor, and has been put into practical use (Patent Documents 4 to 4). 6).

  On the other hand, as a charging device used in an electrophotographic apparatus, a charging device that comes in contact with a photoconductor that can achieve downsizing, low ozone, and low power of the charging device is put into practical use instead of the corona charging that has been conventionally used. Has been. A conductive charging member is brought into contact with the member to be charged, a predetermined charging bias is applied to the charging member, a proximity discharge is generated in a minute gap between the charging member and the member to be charged, and the surface of the member to be charged is predetermined. It is charged to the polarity and potential. Examples of the charging member include a roller type (charging roller), a fur brush type, a magnetic brush type, and a blade type (Patent Documents 7 to 10).

However, these contact charging devices are characterized in that charging is performed in a minute space between the photosensitive member and the charging member, as compared with a charging device that does not contact the photosensitive member (such as corona charging). In other words, since charging is performed at a position closer to the photoconductor, the surface of the photoconductor tends to be chemically deteriorated as compared with a conventional non-contact charging device. The chemical deterioration of the surface of the photoconductor here means a phenomenon in which ozone or charged particles generated by proximity discharge collide with resin molecules on the surface of the photoconductor to cut molecular chains and lower the molecular weight of the resin molecules. Represents a phenomenon in which the resin is weakened and the wear of the surface of the photoreceptor is promoted.
Conventionally, in order to prevent the chemical deterioration of the surface of the photoconductor, a countermeasure such as applying a protective film such as zinc stearate on the surface of the photoconductor has been taken (Patent Documents 11 to 12).
However, when this contact charging device is combined with the above-mentioned photoreceptor having a high surface hardness and a roughened surface for a long life, a groove on the roughened surface grows and eventually becomes a scratch. May occur in the image.
The groove on the roughened surface of the photoconductor has a thin photosensitive layer corresponding to the depth of the groove, so the distance from the photoconductor base is close and the resistance tends to be low. The resin strength of the groove portion is selectively weakened due to the deterioration, and is worn due to cleaning rubbing or the like.
Since the non-grooved part has high hardness, only the groove part weakened due to chemical deterioration is selectively worn and the groove grows, and the discharge further concentrates on the grown groove. The surface will be deeply shaved. As a result, the image quality deteriorates and appears as a streak in the image, and the conventional techniques have not solved the problem that hinders the extension of the service life.
As described above, even if a method of applying a protective film to the surface of the photoconductor is taken as a countermeasure, the photoconductor with a roughened surface tends to be insufficiently applied to the groove portion, and the effect cannot be obtained.
JP 05-035156 A Japanese Patent Laid-Open No. 05-088977 Japanese Patent Laid-Open No. 06-083091 JP 2004-279967 A JP 2006-011047 A JP 2007-086160 A Japanese Patent Laid-Open No. 05-027551 Japanese Patent Laid-Open No. 05-273835 Japanese Patent Laid-Open No. 06-230615 JP 09-222722 A JP 2002-244516 A JP 2002-244487 A

An object of the present invention is to provide an image forming method that solves the above-mentioned problems of the prior art.
That is, the object of the present invention is to use a surface of a photoconductor having a high wear resistance for a long life, and also to use a contact charging device that can be expected to reduce the size and power of the device. An object of the present invention is to provide an image forming method that prevents selective chemical deterioration of a roughened groove on the surface of the photoreceptor and has no adverse effects and high durability.

The invention according to the present application for achieving the above-described object is as follows.
<1> A charging step for charging a photosensitive member having a photosensitive layer on a conductive support, and an electrostatic latent image is formed on the charged photosensitive member, and a developer is transferred to the electrostatic latent image for visualization. An image forming method including a developing step, wherein the surface of the photoreceptor has 20 or more 1000 grooves having a groove width of 0.5 μm or more and less than 40.0 μm per unit length of 1000 μm in the bus bar direction of the photoreceptor. Less than or equal to the sum [μm] of the groove widths W1 to Wi per unit length of 1000 μm satisfying the following formula (1), the developer includes toner particles containing at least a binder resin and a colorant, and A developer containing an inorganic fine powder A having a number average particle size of 80 nm or more and less than 300 nm and an inorganic fine powder B having a number average particle size of 500 nm or more and less than 2000 nm, wherein the release rate α of the inorganic fine powder A from toner particles is α. ( A) is 20.0% by mass or more and less than 40.0% by mass, and the free rate α (B) of the inorganic fine powder B from the toner particles is 50.0% by mass or more and less than 75.0% by mass. There is provided an image forming method.

上記絶対値放電電流量、並びに、帯電周波数及び感光体の線速の関係を有することにより、帯電器が小型省電力の接触帯電器であっても、本発明の効果をより高めることが可能である。
<2> In the charging step, the photosensitive member is charged using a bias applying unit that applies a charging bias in which an AC voltage is superimposed on a DC voltage, and an absolute value discharge current value in the longitudinal direction in the charging step is 100 μA. / Cm or less, and satisfies the following formula (2) when the charging frequency of the AC voltage is f [Hz] and the linear velocity of the photoconductor is v [mm / sec] <1>. The image forming method according to 1>.

By having the relationship between the absolute value discharge current amount, the charging frequency, and the linear velocity of the photoconductor, the effect of the present invention can be further enhanced even if the charger is a small power-saving contact charger. is there.

<3> The universal hardness value of the surface of the photoreceptor is 150 N / mm ² or more and less than 240 N / mm ² , and the elastic deformation rate of the surface of the photoreceptor is 44% or more and less than 65%. The image forming method according to <1> or <2>, wherein
By satisfying the universal hardness and the elastic deformation rate, the effect of the present application can be further enhanced.

  According to the present invention, the surface of a photoconductor having a high wear resistance is used for a long life, and the photoconductor can be used even if contact charging that can be expected to reduce the size and power of the apparatus is used. It is possible to provide a highly durable image forming method by preventing the selective chemical degradation of the roughened grooves on the surface.

The image forming method of the present invention includes a charging step of charging a photosensitive member having a photosensitive layer on a conductive support, and forming an electrostatic latent image on the charged photosensitive member, and developing the electrostatic latent image on the developer. The image forming method includes a developing step for transferring and visualizing a groove, wherein a groove having a groove width of 0.5 μm or more and less than 40.0 μm is formed on the surface of the photoconductor per unit length of 1000 μm in the generatrix direction of the photoconductor. There are 20 or more and less than 1000, the sum [μm] of the groove widths W1 to Wi per unit length of 1000 μm satisfies the following formula (1), and the developer contains at least a binder resin and a colorant Toner particles, and an inorganic fine powder A having a number average particle size of 80 nm or more and less than 300 nm and an inorganic fine powder B having a number average particle size of 500 nm or more and less than 2000 nm, and the toner particles of the inorganic fine powder A The liberation rate α (A) from the particles is 20.0% by mass or more and less than 40.0% by mass, and the liberation rate α (B) from the toner particles of the inorganic fine powder B is 50.0% by mass or more. It is less than 75.0% by mass.

  The developer used in the present invention includes toner particles containing at least a binder resin and a colorant, inorganic fine powder A having a number average particle diameter of 80 nm or more and less than 300 nm, and inorganic having a number average particle diameter of 500 nm or more and less than 2000 nm. A developer containing fine powder B. The liberation rate α (A) of the inorganic fine powder A from the toner particles is 20.0% by mass or more and less than 40.0% by mass, and the liberation rate α (B) of the inorganic fine powder B from the toner particles. ) Is 50.0 mass% or more and less than 75.0 mass%.

  The method for producing the developer used in the present invention is not particularly limited, and a suspension polymerization method, an emulsion polymerization method, an association polymerization method, a kneading and pulverization method, and the like are used.

First, a method for producing the developer using the kneading and pulverizing method will be described.
The binder resin for toner particles used in the developer is preferably a polyester resin, a vinyl copolymer resin, an epoxy resin, or a hybrid resin having a vinyl polymer unit and a polyester unit.

When a polyester resin is used as the binder resin, polyhydric alcohol and polycarboxylic acid, polyhydric carboxylic acid anhydride, polyhydric carboxylic acid ester, or the like is used as a raw material monomer.
Specifically, for example, as the dihydric alcohol, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis ( 4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2 -Alkylene oxide adducts of bisphenol A such as bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, ne Pentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, Examples thereof include hydrogenated bisphenol A.

  Examples of the trivalent or higher alcohol include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Can be mentioned.

  Examples of the carboxylic acid include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid or anhydrides thereof; alkyldicarboxylic acids such as succinic acid, dodecenyl succinic acid, adipic acid, sebacic acid and azelaic acid or anhydrides thereof; And succinic acid substituted with an alkyl group having 6 to 12 carbon atoms or anhydride thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid or anhydrides thereof;

Examples of the trivalent or higher polyvalent carboxylic acid for forming a polyester resin having a crosslinking site include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2 , 4-Naphthalenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, and anhydrides and ester compounds thereof. The amount of the trivalent or higher polyvalent carboxylic acid used is 0.1 to 1.
9 [mol%] is preferable.

  Among them, in particular, a carboxylic acid composed of a bisphenol derivative represented by the following structural formula (1) as a diol component and a divalent or higher carboxylic acid or an acid anhydride thereof, or a lower alkyl ester thereof (for example, fumaric acid) Polyester resins obtained by polycondensation of these resins with maleic acid, maleic anhydride, phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid and the like as acid components are preferable because they have good charging characteristics.

  Further, when a vinyl copolymer resin is used as the binder resin, examples of the vinyl monomer for producing the vinyl copolymer resin include the following. Styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-chloro styrene, 3, Styrene derivatives such as 4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene; unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; C such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride Vinyl halides; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, methacryl Methacrylic acid esters such as dodecyl acid, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, propyl acrylate, n-acrylate Butyl, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc. Acrylic esters; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N -N-vinyl compounds such as vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

In addition, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, Alkenyl succinic acid half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester unsaturated dibasic acid half ester; dimethylmaleic acid, dimethyl fumaric acid unsaturated dibasic acid ester; acrylic acid, meta Α, β-unsaturated acids such as rillic acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic anhydride, the α, β-unsaturated acid and lower fatty acids And monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof.
Further, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1-hydroxy-1) -Methylhexyl) monomers having a hydroxy group such as styrene.

  The vinyl copolymer resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. Examples of the crosslinking agent used in this case include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5 -Diacrylate compounds linked by alkyl chains such as pentanediol diacrylate, 1,6 hexanediol diacrylate, neopentyl glycol diacrylate and the like, and acrylates of the above compounds replaced with methacrylate; diethylene glycol diacrylate, triethylene Glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate Diacrylate compounds linked by an alkyl chain containing an ether bond such as a rate, and those obtained by replacing the acrylate of the above compound with methacrylate; polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane Diacrylate compounds such as diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate and the like, and diacrylate compounds linked by a chain containing an ether bond and acrylates of the above compounds The thing replaced with a methacrylate is contained.

  Examples of polyfunctional cross-linking agents include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds replaced with methacrylate; Allyl cyanurate and triallyl trimellitate are included.

Examples of the polymerization initiator used for producing the vinyl copolymer resin include 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4-dimethyl). Valeronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2 methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1,1 '-Azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2'-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl-4 -Methoxyvaleronitrile, 2,2'-azobis (2-methyl-propane), methyl ethyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide Ketone peroxides such as 2, 2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di -T-butyl peroxide, t-butyl cumyl peroxide, di-cumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, Lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, di-isopropyl peroxydicarbonate,
Di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-2-ethoxyethyl peroxycarbonate, di-methoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) Peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxyneodecanoate, t-butylperoxy-2-ethylhexanoate, t- Butyl peroxylaurate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxyisophthalate, t-butyl peroxyallyl carbonate, t-amyl peroxy 2-ethyl Hexanoate, di -t- butyl peroxy hexahydro terephthalate, include di -t- butyl peroxy azelate.

Further, when a hybrid resin having a polyester unit and a vinyl polymer unit is used as the binder resin, even better durability can be expected. The “hybrid resin” in the present invention means a resin in which a vinyl polymer unit and a polyester unit are chemically bonded.
Specifically, the hybrid resin is formed by a transesterification reaction between a polyester unit and a vinyl polymer unit obtained by polymerizing a monomer having a carboxylic acid ester group such as (meth) acrylic acid ester. A graft copolymer (or block copolymer) in which a vinyl polymer is a trunk polymer and a polyester unit is a branch polymer is preferable.

  In the present invention, “polyester unit” refers to a portion derived from polyester, and “vinyl polymer unit” refers to a portion derived from a vinyl polymer. The polyester monomer constituting the polyester unit is the polyvalent carboxylic acid and polyhydric alcohol described above, and the monomer constituting the vinyl polymer unit is the monomer component having the vinyl group described above.

  When a hybrid resin is used as the binder resin, it is preferable that a monomer component capable of reacting with both units is contained in the vinyl polymer unit and / or the polyester unit component. Examples of monomers that can react with the vinyl polymer unit among monomers constituting the polyester unit component include unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof. Examples of the monomer constituting the vinyl polymer unit that can react with the polyester unit include a vinyl monomer having a carboxyl group or a hydroxy group, and acrylic acid or methacrylic acid esters.

  As a method of obtaining a reaction product of a vinyl polymer unit and a polyester unit, that is, a hybrid resin, in the presence of a polymer containing a monomer component capable of reacting with each of the vinyl polymer unit and the polyester unit listed above, A method obtained by polymerizing one or both units is preferred.

Examples of the method for producing the hybrid resin constituting the toner particles contained in the developer used in the present invention include the following production methods (1) to (6).
(1) A method obtained by blending after producing a vinyl polymer unit, a polyester unit and a hybrid resin component. The blend is produced by dissolving and swelling in an organic solvent (for example, xylene) and then distilling off the organic solvent. As the hybrid resin component, a vinyl polymer unit and a polyester unit are separately manufactured, dissolved and swollen in a small amount of an organic solvent, an esterification catalyst and an alcohol are added, and the ester exchange reaction is performed by heating. An ester compound synthesized in this manner can be used.
(2) A method of obtaining a hybrid resin having a vinyl polymer unit and a polyester unit by producing a vinyl polymer unit and then reacting a polyester unit and / or a hybrid resin component in the presence thereof. The hybrid resin component is produced by a reaction between a vinyl polymer unit (a vinyl monomer can be added if necessary) and a polyester monomer (alcohol, carboxylic acid) and / or polyester unit. Also in this case, an organic solvent can be appropriately used.
(3) A method of producing a hybrid resin having a polyester unit and a vinyl polymer unit by reacting a vinyl polymer unit and / or a hybrid resin component in the presence of the polyester unit after the polyester unit is produced. The hybrid resin component is produced by a reaction between a polyester unit (a polyester monomer can be added if necessary) and a vinyl monomer and / or vinyl polymer unit. Also in this case, an organic solvent can be appropriately used.
(4) After producing a vinyl polymer unit and a polyester unit, respectively, a vinyl monomer and / or a polyester monomer (alcohol, carboxylic acid) are added in the presence of these polymer units and reacted to give a vinyl polymer weight. A hybrid resin having a coalesced unit and a polyester unit is produced. Also in this case, an organic solvent can be appropriately used.
(5) After producing a hybrid resin component having a vinyl polymer unit and a polyester unit, a vinyl monomer and / or polyester monomer (alcohol, carboxylic acid) is added to perform addition polymerization and / or condensation polymerization reaction. Thus, a hybrid resin having a vinyl polymer unit and a polyester unit is produced. In this case, as the hybrid resin component, those produced by the production methods (2) to (4) can be used, and those produced by a known production method can be used as necessary. Furthermore, an organic solvent can be used as appropriate.
(6) A hybrid resin having a vinyl polymer unit and a polyester unit is produced by mixing a vinyl monomer and a polyester monomer (alcohol, carboxylic acid, etc.) and continuously performing addition polymerization and condensation polymerization reaction. Furthermore, an organic solvent can be used as appropriate.
In the above production methods (1) to (5), a hybrid resin may be produced using a plurality of vinyl polymer units and polyester units having different molecular weights and cross-linking degrees.

  The glass transition temperature of the binder resin is preferably 40 ° C. to 90 ° C., more preferably 45 ° C. to 85 ° C. The acid value of the binder resin is preferably 1 to 40 mgKOH / g.

The toner particles contain a colorant as a constituent element. The colorant is not particularly limited, and a known appropriate pigment or dye can be used.
Examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine yellow, alizarin yellow, bengara, phthalocyanine blue, and the like. A preferable addition amount of the pigment is 0.1 to 20 parts by mass, and more preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  Examples of the dye include azo dyes, anthraquinone dyes, xanthene dyes, methine dyes, and the like. A preferable addition amount of the dye is 0.1 to 20 parts by mass, more preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

The toner particles can contain a release agent as required.
Examples of release agents that can be used in the present invention include the following. Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax and paraffin wax; oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax; aliphatic hydrocarbon waxes or oxides thereof Block copolymers; waxes mainly composed of fatty acid esters such as carnauba wax, sazol wax, and montanic acid ester wax; and fatty acid esters such as deoxidized carnauba wax partially or wholly deoxidized included. Further, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, and seryl alcohol Saturated alcohols such as melyl alcohol; long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylene bis stearic acid amide, ethylene biscaprin Saturated fatty acid bisamides such as acid amide, ethylene bislauric acid amide, hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl Unsaturated fatty acid amides such as dipinamide, N, N-dioleyl sebacic acid amide; aromatic bisamides such as m-xylenebisstearic acid amide, N, N-distearylisophthalic acid amide; calcium stearate, laur Fatty acid metal salts such as calcium phosphate, zinc stearate and magnesium stearate (generally called metal soap); waxes grafted to aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid A partially esterified product of a fatty acid such as behenic acid monoglyceride and a polyhydric alcohol; a methyl ester compound having a hydroxyl group obtained by hydrogenation of vegetable oil or the like; Among these release agents, one or more release agents may be contained in the toner particles as necessary.

A preferable addition amount of the release agent is 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass per 100 parts by mass of the binder resin.
In addition, these release agents can usually be contained in the toner particles by dissolving the resin in a solvent, increasing the temperature of the resin solution, adding and mixing with stirring, or mixing at the time of kneading.

As the developer, a charge control agent can be used as necessary in order to further stabilize the chargeability. Examples of charge control agents include:
As the negative charge control agent for controlling the developer to be negative charge, an organometallic complex or a chelate compound is effective. Examples of negative charge control agents include monoazo metal complexes, aromatic hydroxycarboxylic acid metal complexes, and aromatic dicarboxylic acid metal complexes. Others include aromatic hydroxycarboxylic acids, aromatic mono and polycarboxylic acids and metal salts thereof, anhydrides or esters thereof, or phenol derivatives of bisphenol.
Examples of positive charge control agents that control the developer to be positively charged include modified products of nigrosine and fatty acid metal salts, tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate As onium salts such as quaternary ammonium salts such as phosphonium salts and their chelating pigments, triphenylmethane dyes and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, etc.) Phosphotungstomolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanic acid, ferrocyanic compound, etc.), diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, and dibutyltin as metal salts of higher fatty acids , Dioctyl tin borate, include diorgano tin borate such as dicyclohexyl tin borate.

  A preferable content of the charge control agent is 0.5 to 10 parts by mass per 100 parts by mass of the binder resin. When the content of the charge control agent is less than 0.5 parts by mass, more stable charging characteristics tend to be difficult to obtain, and when it exceeds 10 parts by mass, compatibility with other materials under low humidity There is a possibility that overcharging is likely to occur.

The toner particles can contain a magnetic material as necessary. As the magnetic material, magnetic oxides such as magnetite, maghematite, and ferrite, and mixtures thereof are preferably used.
Examples of the magnetic material include lithium, beryllium, boron, magnesium, aluminum, silicon, phosphorus, sulfur, germanium, titanium, zirconium, tin, lead, zinc, calcium, barium, vanadium, chromium, manganese, cobalt, copper, Magnetism containing at least one element selected from the group consisting of nickel, gallium, indium, silver, palladium, gold, platinum, tungsten, molybdenum, niobium, osmium, strontium, yttrium, technetium, ruthenium, rhodium, bismuth, etc. Contains iron oxide. Of these, lithium, beryllium, boron, magnesium, aluminum, silicon, phosphorus, germanium, titanium, zirconium, tin, sulfur, calcium, barium, vanadium, chromium, manganese, cobalt, copper, nickel, strontium, bismuth and zinc are preferred. . Particularly preferred is magnetic iron oxide containing an element selected from magnesium, aluminum, silicon, phosphorus and zirconium as a different element. These elements may be incorporated into the iron oxide crystal lattice, may be incorporated into the iron oxide as oxides, or may be present on the surface as oxides or hydroxides. It is preferable to be contained in iron oxide.
The number average particle diameter of these magnetic materials is preferably 0.05 μm or more and less than 1.0 μm, more preferably 0.1 μm or more and less than 0.5 μm. The BET specific surface area by the preferable nitrogen adsorption of the magnetic material is 2 m ² / g to 40 m ² / g, more preferably 4 m ² / g to 20 m ² / g. A preferable magnetic property of the magnetic material is that the saturation magnetization measured at a magnetic field of 795.8 kA / m is 10 Am ² / kg to 200 Am ² / kg, and more preferably 70 Am ² / kg to 100 Am ² / kg. A preferable remanent magnetization is 1 Am ² / kg to 100 Am ² / kg, more preferably ² Am ² / kg to ²⁰ Am ² / kg. A preferable coercive force is 1 kA / m to 30 kA / m, and more preferably 2 kA / m to 15 kA / m. A preferable content of the magnetic body is 20 parts by mass to 200 parts by mass with respect to 100 parts by mass of the binder resin.

The developer used in the present invention is produced, for example, by the following method.
The binder resin, colorant, and, if necessary, other additives and the like are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then a heat kneader such as a heating roll, a kneader or an extruder is used. The mixture is melt kneaded, cooled and solidified, and pulverized and classified to obtain toner particles. Furthermore, the developer is prepared by sufficiently mixing the toner particles, inorganic fine powder A and inorganic fine powder B, which will be described later, and, if necessary, a desired additive using a mixer such as a Henschel mixer. Note that the inorganic fine powder A and the inorganic fine powder B, which will be described later, and a desired additive as required can be externally added at any time after the production of the toner particles. For example, the toner particles can be externally added in the step of classifying or spheroidizing the toner particles.

Examples of the mixer include Henschel mixer (Mitsui Mining Co., Ltd.); Super mixer (Kawata Co., Ltd.); Ribocorn (Okawara Seisakusho Co., Ltd.); Pin mixer 1 (manufactured by Taiheiyo Kiko Co., Ltd.); Ladige mixer (manufactured by Matsubo Co., Ltd.) is included, examples of kneaders are KRC kneader (manufactured by Kurimoto Iron Works Co., Ltd.); bus co kneader (manufactured by Buss Co., Ltd.) TEM type extruder (manufactured by Toshiba Machine Co., Ltd.); TEX twin-screw kneader (manufactured by Nippon Steel Works); PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.); triple roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho) ; Needex (Mitsui Mining Co., Ltd.); MS pressure kneader, Nider Ruder (Moriyama Seisakusho); Banbury mixer (Kobe Steel Co., Ltd.) included That.
Examples of the pulverizer used for the pulverization include a counter jet mill, a micron jet,
Inomizer (manufactured by Hosokawa Micron); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Industrial Co., Ltd.); Cross jet mill (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nisso Engineering Co., Ltd.); Mills (manufactured by Seisin Corporation); Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.); turbo mills (manufactured by Turboe Corporation), and examples of classifiers include a class seal, a micron classifier, and a pedic classifier (Seishin company) Turboclassifier (Nisshin Engineering); Micron separator, Turboplex (ATP), TSP separator (Hosokawa Micron); Elbow Jet (Nittetsu Mining), Dispersion separator (Nippon Pneumatic Engineering) YM micro cut (made by company) River Shoji Co., Ltd.) is included.
Examples of sieving devices used for sieving coarse particles in the production of the developer include Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resona Sheave, Gyroshifter (Tokuju Kogakusha Co., Ltd.); Vibrasonic System (Dalton) Sonic Clean (manufactured by Shinto Kogyo Co., Ltd.); turbo screener (manufactured by Turboe Sangyo Co., Ltd.); micro shifter (manufactured by Hadano Sangyo Co., Ltd.); circular vibrating sieve, etc.
In particular, it is preferable to use a mechanical pulverizer as the pulverizing means used in the developer manufacturing method in which the shape of coarse particles is controlled. Examples of the mechanical pulverizer include a pulverizer inomizer manufactured by Hosokawa Micron Corporation, a pulverizer KTM manufactured by Kawasaki Heavy Industries, Ltd., and a turbo mill manufactured by Turbo Industry Co., Ltd. It is preferable to use these apparatuses as they are or after being appropriately modified.

Next, a method for producing the developer when the suspension polymerization method is used will be described.
First, a colorant, a polymerization initiator, and, if necessary, a release agent, a charge control agent, and other additives are added to the polymerizable monomer, and uniformized by a homogenizer, an ultrasonic disperser, or the like. A polymerizable monomer composition is prepared by dissolving or dispersing in Next, the polymerizable monomer composition is dispersed in an aqueous phase containing a dispersion stabilizer by a normal stirrer, homogenizer, homomixer or the like. At this time, granulation is preferably carried out by adjusting the stirring speed and time so that the droplets of the polymerizable monomer composition have the desired toner particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer. The polymerization temperature is preferably set to 40 ° C. or higher, generally 50 ° C. to 90 ° C. In addition, the temperature may be raised in the latter half of the polymerization reaction, and further, in order to remove unreacted polymerizable monomers and by-products that cause odors when fixing the developer, the latter half of the reaction or at the end of the reaction A part of the aqueous medium may be distilled off. After completion of the reaction, the produced toner particles are washed, collected by filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 parts by mass to 3000 parts by mass of water as a dispersion medium with respect to 100 parts by mass of the polymerizable monomer composition.

  Toner particle size distribution control and particle size control are carried out by adjusting the pH of the system during granulation, by changing the type and amount of a sparingly water-soluble inorganic salt and a dispersant that acts as a protective colloid, and mechanical equipment conditions. For example, it can be performed by controlling the stirring conditions such as the circumferential speed of the rotor, the number of passes, the shape of the stirring blades, the shape of the container or the solid content concentration in the aqueous solution.

  Examples of the polymerizable monomer used in the suspension polymerization method include styrene monomers such as styrene, o- (m-, p-) methylstyrene, m- (p-) ethylenestyrene; (meth) acrylic Methyl methacrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid ester monomers such as 2-ethylhexyl, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; simple substances such as butadiene, isoprene, cyclohexane, (meth) acrylonitrile, acrylamide A monomer is preferably used.

As the charge control agent used in the suspension polymerization method, known charge control agents can be used, but a charge control agent having no polymerization inhibition and no solubilized product in an aqueous system is particularly preferable. Specific compounds include, as charge control agents for controlling negative charge, salicylic acid, naphthoic acid, dicarboxylic acid, metal compounds of their derivatives, polymer compounds having sulfonic acid in the side chain, boron compounds, urea compounds, Silicon compounds, calixarene, etc. can be used. On the other hand, a quaternary ammonium salt, a polymer compound having a quaternary ammonium salt in the side chain, a guanidine compound, an imidazole compound, or the like is preferably used as a charge control agent for controlling positive charge. The charge control agent is preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Examples of the polymerization initiator used in the suspension polymerization method include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane). -1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo-based polymerization initiators such as azobisisobutylnitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroxy Peroxide-based polymerization initiators such as peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide are used.

  The addition amount of the polymerization initiator varies depending on the target degree of polymerization, but is generally used by adding 0.5% by mass to 20% by mass with respect to the polymerizable monomer. The kind of the polymerization initiator is slightly different depending on the polymerization method, but may be used alone or mixed with reference to the 10-hour half-life temperature.

Examples of the dispersant used in the suspension polymerization method include, as an inorganic oxide, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide. , Aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic substance, ferrite and the like. As the organic compound, for example, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like are used dispersed in an aqueous phase.
These dispersants are preferably used in an amount of 0.2 to 2.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Although these commercially available dispersants may be used as they are, they can also be obtained by producing the inorganic compound in a dispersion medium under high-speed stirring in order to obtain dispersed particles having a fine uniform particle size. For example, in the case of calcium phosphate, a dispersant preferable for the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high-speed stirring.

  In order to refine these dispersants, 0.001 to 0.1 parts by mass of a surfactant may be used in combination. Specifically, commercially available nonionic, anionic and cationic surfactants can be used, such as sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, Calcium oleate is preferably used.

  The toner particles produced by the above method are classified as necessary. Next, in the same manner as in the kneading and pulverization method, the obtained toner particles are added with inorganic fine powder A and inorganic fine powder B, which will be described later, and desired additives as necessary, and then sufficiently obtained by a mixer such as a Henschel mixer. The developer is prepared by mixing. Note that inorganic fine powder A and inorganic fine powder B, which will be described later, and a desired additive as necessary can be added at any time after the production of the toner particles. For example, it can be added to the toner particles in the step of classifying or spheroidizing the toner particles.

  As described above, the developer used in the present invention includes the toner particles, the inorganic fine powder A having a number average particle diameter of 80 nm or more and less than 300 nm, and the inorganic fine powder B having a number average particle diameter of 500 nm or more and less than 2000 nm. The inorganic fine powder A has a liberation rate α (A) from the toner particles of 20.0% by mass or more and less than 40.0% by mass, and the inorganic fine powder B has a liberation rate α (B) from the toner particles. It is 50.0 mass% or more and less than 75.0 mass%.

The liberation rate in the present invention is the mass ratio [%] of the inorganic fine powder that is detached from the toner particles when the developer is dispersed in an aqueous surfactant solution and the inorganic fine powder is peeled off at a specific dispersion strength. Means.
In the present invention, it has been found that the liberation rate has a correlation with the proportion of the inorganic fine powder that is detached from the toner particles due to the share of the developer in the electrophotographic process, particularly the developing process.
In the present invention, it has also been found that the following effects can be obtained by controlling the liberation rate of the specific inorganic fine powder to a specific value.
That is, in the present invention, since the inorganic fine powder A has the above particle diameter and release rate, an appropriate amount of the inorganic fine powder A released from the toner particles can be supplied to the photoreceptor. Further, since the inorganic fine powder B has the above particle diameter and release rate, the inorganic fine powder B is detached from the toner particles and is damped to the cleaning member, and the inorganic fine powder A slipping from the inorganic fine powder B is a groove of the photoreceptor. Guided to the part and evened. The inorganic fine powder A uniformly present in the groove portion of the photosensitive member inhibits the selective discharge of the groove portion, thereby selectively deteriorating the resin in the groove portion and selectively in the groove portion due to the deterioration of the resin. Wear can be prevented.
In order to control the inorganic fine powder A and the inorganic fine powder B to predetermined release rates, respectively, for example, optimizing the mixing time in the adding step of the inorganic fine powder A and the inorganic fine powder B. Different mixing conditions may be used.

  Examples of the inorganic fine powder include metal oxides such as zinc, aluminum, cerium, cobalt, iron, zirconium, chromium, manganese, strontium, tin, and antimony, calcium titanate, magnesium titanate, and strontium titanate. Metal salts such as metal oxides, barium sulfate, calcium carbonate, magnesium carbonate, aluminum carbonate, viscosity minerals such as kaolin, phosphate compounds such as apatite, silicate compounds such as silica, silicon carbide and silicon nitride, carbon black, graphite And carbon powders.

The selection method and preparation method of the inorganic fine powder A and the inorganic fine powder B are not particularly limited as long as they are within the scope of the present invention. Different materials may be selected as the inorganic fine powder A and the inorganic fine powder B, or the same material with different particle sizes may be selected. The same substance with different shapes may be selected, those with different preparation methods may be selected, or different surface treatments may be applied.
For example, when the toner particles are negatively charged, an inorganic fine powder having a weakly positive charging characteristic is preferable because it is difficult to transfer to the transfer material and easily remains on the photoreceptor. Furthermore, among the above, strontium titanate is more preferable as the inorganic fine powder A and the inorganic fine powder B because the release rate from the toner particles can be easily controlled and a preferable particle diameter can be obtained.

The number average particle diameter of the inorganic fine powder A is 80 nm or more and less than 300 nm as described above. The number average particle diameter is preferably 80 nm or more and less than 150 nm. By setting the number average particle diameter within the above range, the inorganic fine powder A can be uniformly dispersed and distributed in the grooves formed in the circumferential direction of the photoreceptor, and as a result, the selective discharge of the groove portions is inhibited. can do.
When the number average particle diameter is smaller than 80 nm, the inorganic fine powder A is supplied even to a portion that is not a groove, and is not uniformly dispersed, causing image density unevenness and density reduction. On the other hand, when the number average particle diameter is 300 nm or more, the cleaning member is clogged, the supply to the photoreceptor is insufficient, the effect of inhibiting the selective discharge of the groove portion is not obtained, and the polishing power is inferior. Image flow is likely to occur.

On the other hand, the number average particle diameter of the inorganic fine powder B is 500 nm or more and less than 2000 nm as described above. In addition, it is preferable that the said number average particle diameter is 500 nm or more and less than 1500 nm.
By setting the number average particle diameter in the above range, the cleaning member can block the developer, the inorganic fine particles A can be passed through and supplied to the photoconductor, and the inorganic fine particles A can be uniformly distributed in the grooves on the surface of the photoconductor. The effect of dispersion and distribution appears preferably.
When the number average particle diameter is smaller than 500 nm, the developer blocking effect is reduced, causing the developer to slip through, and the inorganic fine powder B itself is easily slipped through, resulting in a decrease in image density. On the other hand, when the number average particle diameter is 2000 nm or more, the inorganic fine powder A slips through to the portion that is not a groove, and the concentration tends to decrease.

The method for measuring the number average particle diameter of the inorganic fine powder A and the inorganic fine powder B is as follows.
First, using an electron microscope, the inorganic fine powder is photographed at a magnification of 50,000 times, and 100 inorganic fine powders are randomly selected from the photographed inorganic fine powder. When the inorganic fine powder has a spherical shape, the diameter of the inorganic fine powder is used, and when the inorganic fine powder has a rectangular parallelepiped shape, the average value of the short diameter and the long diameter is used as the particle diameter of the inorganic fine powder. The average value of the particle size of the body was taken as the number average particle size.

The liberation rate α (A) of the inorganic fine powder A from the toner particles is 20.0% by mass or more and less than 40.0% by mass. In addition, it is preferable that the said liberation rate (alpha) (A) is 25 to 35 mass%.
On the other hand, the release rate α (B) of the inorganic fine powder B from the toner particles is 50.0 mass% or more and less than 75.0 mass%. The liberation rate α (B) is preferably 55% by mass or more and less than 70% by mass.
When the liberation rate α (A) of the inorganic fine powder A is 40.0% by mass or more, the amount of the desorbed inorganic fine powder A becomes excessive, and the discharge of the portion that is not the groove is inhibited, so that the photoconductor The surface cannot be charged to a predetermined polarity and potential, resulting in uneven image density and reduced density. On the other hand, if the liberation rate α (A) of the inorganic fine powder A is less than 20.0% by mass, the supply amount to the photoreceptor is insufficient, and the effect of preventing the selective chemical deterioration of the groove portion is insufficient. .
On the other hand, when the liberation rate α (B) of the inorganic fine powder B is 75.0% by mass or more, even the inorganic fine powder B is supplied to the photoconductor to inhibit charging and reduce the image density. Cause. Further, if the liberation rate α (B) of the inorganic fine powder B is less than 50.0% by mass, the supply of the inorganic fine powder A to the photoreceptor becomes unstable, and the inorganic fine powder A is uniformly distributed in the groove portion. Therefore, the toner cannot be present, and the cleaning becomes unstable, causing the toner to slip through.

A method for measuring the release rate of the inorganic fine powder from the toner particles will be described.
(1) When the magnetic particles are contained in the toner particles and the magnetic particles are not contained in the inorganic fine particles, the measurement is performed by the following method.
(1-1) A solution prepared by adding 2% by mass of nonionic surfactant, preferably Contaminone N (manufactured by Wako Pure Chemical Industries, Ltd .: trade name) to ion-exchanged water is prepared. In a 50 ml polyethylene sample bottle that can be sealed, 40 g (20 ° C.) of the prepared solution is added, 1.5 g of a measurement sample (developer) is added, and the mixture is allowed to stand on a magnetic sheet for 1 hour.
(1-2) The sample that has been allowed to stand for 1 hour is shaken for 1 minute at 1.67S ^-1 using a Yayoi shaker YS-LD (manufactured by Yayoi Co., Ltd .: trade name). At this time, the angle of shaking is such that the shaking column moves 15 degrees forward and 20 degrees backward, assuming that the vertical (vertical) of the shaker is 0 degree. The sample bottle is fixed and shaken on a fixing holder (with the sample bottle lid fixed on the extension of the center of the column) attached to the tip of the column. Place the shaken sample bottle on the magnet and let stand for 1 minute.
(1-3) Collect the supernatant of the sample left on the magnet for 1 minute in another sample bottle. If there is a lump of developer, remove it.
(1-4) The sample bottle containing the developer, excluding the supernatant, is dried in a vacuum dryer (40 ° C.) for 10 hours or more without a lid, and then pelletized and inorganic fine powder by fluorescent X-rays Measure the X-ray fluorescence intensity of the element corresponding to the body.
(1-5) For the sample not subjected to the above separation treatment and the toner particle sample to which the inorganic fine powder is not added, the fluorescent X-ray intensity of the same element is measured, and the inorganic fine powder is released by the following formula. Find the rate.

(2) In the above (1), when the inorganic fine powder A and the inorganic fine powder B do not have different elements and cannot be identified by fluorescent X-rays, the respective release rates are determined by particle size distribution measurement as follows. calculate.
(2-1) In 200 ml of ion-exchanged water, 1.5 [g] of a measurement sample (toner) and 2 ml of a nonionic surfactant, preferably Contaminone N (made by Wako Pure Chemical Industries, Ltd .: trade name) In addition, the mixture is dispersed for 10 hours with an ultrasonic disperser to release the total amount of the external additive added to the toner. The supernatant liquid and toner produced at this time are separated in the same manner as in the above (1-3) when the toner particles contain a magnetic substance, and when the toner particles do not contain a magnetic substance, the following (3-3) ), And the fluorescent X-ray intensity is measured in the same manner as in (1-4) above, and [X-ray intensity before separation−X-rays after separation] in the calculation formula of (1-5) above. Intensity], the fluorescent X-ray intensity of the element corresponding to the total amount of the external additive added to the toner is calculated. Furthermore, the particle size distribution of the inorganic fine powders A and B liberated in the obtained supernatant is measured by the following method (2-3), and the ratio 1 of the inorganic fine powders A and B is calculated. By multiplying the fluorescent X-ray intensity of the element corresponding to the total amount of the external additive externally added to the toner by the ratio 1 of the inorganic fine powders A and B, the inorganic fine powders A and B externally added to the toner are respectively obtained. The fluorescent X-ray intensity of the corresponding element (the fluorescent X-ray intensity 1 of the element corresponding to the total amount of the inorganic fine powder A and the fluorescent X-ray intensity 1 of the element corresponding to the total amount of the inorganic fine powder B) is calculated.
(2-2) Next, the particle size distribution of the inorganic fine powders A and B released in the supernatant liquid generated in the step (1-3) above was measured by the same method as in (2-3) below. The ratio 2 of the inorganic fine powders A and B is calculated. Each of the inorganic fine powder A and the inorganic fine powder B is obtained by multiplying the fluorescent X-ray intensity of the element corresponding to the inorganic fine powder obtained by the method (1-4) above by the ratio 2 of the inorganic fine powder A and B. The fluorescent X-ray intensity of the element corresponding to (the fluorescent X-ray intensity 2 of the element corresponding to the inorganic fine powder A and the fluorescent X-ray intensity 2 of the element corresponding to the inorganic fine powder B) are calculated. [Fluorescent X-ray intensity 2 of the element corresponding to the inorganic fine powder A / Fluorescent X-ray intensity 1 of the element corresponding to the total amount of the inorganic fine powder A] × 100, [Fluorescence X of the element corresponding to the inorganic fine powder B] Line intensity 2 / Fluorescence X-ray intensity 1] × 100 of an element corresponding to the total amount of the inorganic fine powder B is defined as the liberation ratio of the inorganic fine powder A and the inorganic fine powder B.
(2-3) As a method for measuring the particle size distribution, an aqueous module is used, and isopropyl alcohol is used as a measurement solvent. First, the measurement system of the laser diffraction type particle size distribution analyzer is washed with isopropyl alcohol for about 5 minutes, and 10 to 25 mg of sodium sulfite is added to the measurement system as an antifoaming agent to execute the background function. Next, 3 to 4 drops of a surfactant is added to 50 ml of isopropyl alcohol, 5 to 25 mg of a measurement sample is further added, and then a dispersion treatment is performed for 1 to 3 minutes with an ultrasonic disperser to obtain a sample solution. Measurement was performed by gradually adding a sample solution into the measurement system of the measurement apparatus and adjusting the sample concentration in the measurement system so that the PIDS on the screen of the apparatus was 45% to 55%. Using this measured value, the mass ratio of the particles corresponding to the particle sizes of the inorganic fine powder A and the inorganic fine powder B calculated from the volume distribution is obtained.

(3) The liberation rate when the toner particles do not contain a magnetic material is measured by the following method.
(3-1) A 50 ml polyethylene sample capable of sealing a solution prepared by adding 2% by mass of nonionic surfactant, preferably Contaminone N (manufactured by Wako Pure Chemical Industries, Ltd .: trade name) to ion-exchanged water. 40 g (20 ° C.) is put into a bottle, 1.5 g of a measurement sample (developer) is added, and the sealed container is shaken lightly and left to stand for 1 hour.
(3-2) The sample left still for 1 hour is shaken for 1 minute at 1.67S ^-1 with a Yayoi type shaker YS-LD (manufactured by Yayoi Co., Ltd .: trade name). At this time, the angle of shaking is such that the shaking column moves 15 degrees forward and 20 degrees backward, assuming that the vertical (vertical) of the shaker is 0 degree. The sample bottle is fixed and shaken on a fixing holder (with the sample bottle lid fixed on the extension of the center of the column) attached to the tip of the column. Immediately transfer the shaken sample to a centrifuge container.
(3-3) The sample transferred to the centrifuge container is a high-speed cooling centrifuge, himac CR20E (manufactured by Hitachi Koki: product name), using an R26A rotor, set temperature is 20 ° C., and acceleration / deceleration is the shortest After centrifuging under the conditions of time and rotation speed of 5.00 S ⁻¹ and rotation time of 3 minutes, the supernatant is quickly collected in another sample bottle. If there is a lump of developer, remove it.
(3-4) The sample bottle containing the developer, excluding the supernatant, is dried for 10 hours or more in a vacuum dryer (40 ° C.) without a lid, and then pelletized and inorganic fine powder by fluorescent X-rays Measure the X-ray fluorescence intensity of the element corresponding to the body.
(3-5) X-ray intensity measurement of the same element was performed on the sample not subjected to the above separation treatment and the toner particle sample to which the inorganic fine powder was not added, similarly to the case of (1) described above. It calculates using the formula as described in (1-5), and calculates | requires the liberation rate of inorganic fine powder.

The content of the inorganic fine powder A contained in the developer used in the present invention is preferably 0.01 to 5.0 parts by mass, more preferably 0.05 parts by mass with respect to 100 parts by mass of the toner particles. Part to 3.0 parts by mass. The preferable content of the inorganic fine powder B is 0.01 to 5.0 parts by mass, more preferably 0.05 to 3.0 parts by mass with respect to 100 parts by mass of the toner particles. By setting the contents of the inorganic fine powder A and the inorganic fine powder B within the above range, the free amount released from the toner particles of the inorganic fine powder A and the inorganic fine powder B at the release rate specified in the present invention. However, this is a preferred range for expressing the effects of the present invention.
When the content of the inorganic fine powder A is larger than 5.0 parts by mass, the amount of the detached inorganic fine powder A tends to be excessive, and the fluidity of the developer tends to decrease, resulting in a decrease in density and image unevenness. Such problems are likely to occur. If the content of the inorganic fine powder A is less than 0.01 parts by mass, the amount of the detached inorganic fine powder A is too small to cause a discharge inhibiting effect, and the cleaning property of the photoreceptor tends to deteriorate. Problems such as image flow are likely to occur.
On the other hand, if the content of the inorganic fine powder B is larger than 5.0 parts by mass, the amount of the detached inorganic fine powder B becomes excessive, and the charge balance of the developer tends to be lost. This problem is likely to occur. If the content of the inorganic fine powder B is smaller than 0.01 parts by mass, the amount of the detached inorganic fine powder B tends to be too small, and the friction of the photosensitive member tends to be difficult to be reduced. The problem is likely to occur.

The liberation rate α (A) of the inorganic fine powder A and the liberation rate α (B) of the inorganic fine powder B are, for example, mixed using a Henschel mixer. It can be adjusted by changing the strength of mixing, such as the shape of the baffle plate and the amount of raw materials to be introduced.

When the classified toner particles, the inorganic fine powder A and the inorganic fine powder B, and a desired additive as necessary are added at the same time and mixed, the free rate α (A ) Is 20.0% by mass or more and less than 40.0% by mass, and the free rate α (B) of the inorganic fine powder B from the toner particles is 50.0% by mass or more and less than 75.0% by mass. Some things may not be obtained at the same time. In that case, each mixing condition may be adjusted to a suitable one, and the mixing method and mixing conditions are not limited as long as the liberation rate falls within the above range.
For example, the charging timing of the inorganic fine powder A and the inorganic fine powder B may be changed during the entire mixing time, or either the inorganic fine powder A or the inorganic fine powder B may be premixed. Furthermore, after mixing except for either the inorganic fine powder A or the inorganic fine powder B, the other may be additionally mixed under different conditions or different devices.
Specifically, for example, if the release rate α (A) of the inorganic fine powder A having a small particle diameter is lowered when they are simultaneously added, for example, the release rate α (B) of the inorganic fine powder B is optimized. The total mixing time is determined, and the toner base and inorganic fine powder B, excluding the inorganic fine powder A, and a desired additive as necessary are mixed to start mixing. It may be stopped at a time obtained by subtracting the mixing time at which α (A) is optimal, and the inorganic fine powder A may be added to perform mixing for the remaining time.

In addition to the inorganic fine powder A and the inorganic fine powder B, the developer used in the present invention includes, as other external additives, inorganic oxides such as silica, alumina and titanium oxide, fine particles such as carbon black and carbon fluoride. An inorganic fine powder having a diameter may be externally added to the toner particles. These impart fluidity and chargeability to the developer.
If the silica, alumina, or titanium oxide added externally to the toner particles and dispersed on the surface of the toner particles are fine particles (fine powder), these fine powders have a high fluidity-imparting effect on the developer. The fine powder is preferably fine particles. These fine powders preferably have a number average particle diameter of 5 nm to 100 nm, more preferably 5 nm to 50 nm.
A preferable addition amount of these inorganic fine powders is 0.03 parts by mass to 5 parts by mass with respect to 100 parts by mass of the toner particles. When the added amount of the inorganic fine powder is less than 0.03 parts by mass, sufficient fluidity imparting effect cannot often be obtained. On the other hand, when the amount is 5 parts by mass or more, the compression index of the toner becomes high, the toner is easily tightened, and an excessive external additive is liberated, which tends to have an adverse effect.

The following substances may be added to the developer, particularly as a fluidity improver. The fluidity improver can improve fluidity by externally adding to the toner particles. Examples of fluidity improvers include: fluororesin powders such as vinylidene fluoride fine powder and polytetrafluoroethylene fine powder; fine powder silica such as wet process silica and dry process silica; fine powder titanium oxide; fine powder alumina; These include silane coupling agents, titanium coupling agents, and treated silica surface-treated with silicone oil.
Further, a preferred fluidity improver is a fine powder produced by vapor phase oxidation of a silicon halogen compound, and is called so-called dry silica or fumed silica.
The particle size of the fluidity improver is preferably in the range of 0.001 μm or more and less than 2 μm as the average primary particle size, and particularly preferably in the range of 0.002 μm or more and less than 0.2 μm. Good to use.

The image forming method of the present invention includes a charging step of charging a photosensitive member having a photosensitive layer on a conductive support, and forming an electrostatic latent image on the charged photosensitive member, and developing the electrostatic latent image on the developer. The present invention relates to an image forming method having a developing step of transferring and visualizing the image.
Here, the photoconductor used in the image forming method of the present invention will be described.
The photoreceptor used in the present invention includes a conductive layer support and a photosensitive layer formed on the conductive layer support.
The photosensitive layer has a structure in which a charge generation layer and a charge transport layer are laminated in this order, or conversely, a structure in which a charge transport layer and a charge generation layer are laminated in this order, and further a charge generation material and a charge transport material are contained in a binder resin. It is possible to adopt any configuration in which a single layer is dispersed.
Further, a conductive layer may be provided between the conductive support and the photosensitive layer, and an intermediate layer may be provided between the conductive layer and the photosensitive layer. Furthermore, the photosensitive layer may have a protective layer formed on the photosensitive layer.

  One of the features of the present invention is that the durability of the photoreceptor is improved. This effect can be achieved when the surface layer constituting the surface of the photoreceptor contains a thermoplastic high-hardness resin or a curable resin. In addition, the surface layer in the photoreceptor preferably has charge transporting properties in any case where the surface layer is a protective layer further provided on the photosensitive layer or is a part of the photosensitive layer.

The curable resin contained in the surface layer of the photoconductor means a resin cured by polymerization or a crosslinking reaction by irradiation with heat, light or radiation.
The surface layer is
(1) A surface layer coating solution containing a thermoplastic high-hardness resin may be applied on the photosensitive layer or the charge generation layer, and the surface and the coating film may be dried as necessary.
(2) A surface layer coating solution containing a compound that can be polymerized or cured by generating active sites such as radicals by irradiation with heat, light or radiation (hereinafter also referred to as “polymerization or curing compound”), You may form by apply | coating on a photosensitive layer or a charge generation layer, and irradiating a formed coating film with a heat | fever, light, or radiation.

  Examples of the thermoplastic high-hardness resin contained in the surface layer include modified polyacrylates and copolymerized polyarylate.

The surface of the photoreceptor used in the present invention has an elastic deformation rate measured by a method described later of preferably 44% or more and less than 65%, more preferably 50% or more and less than 65%. By setting the elastic deformation rate within the above range, it is possible to suppress the occurrence of scratches on the surface of the photoreceptor and the fusion of the developer or the like during durability. The surface of the photosensitive member, the universal hardness value measured and calculated by a method described later (HU) of preferably less than 150 N / mm ² or more ^{240N / mm 2, 160N / mm} 2 or more 210N / mm More preferably, it is less than ² . Thereby, the suppression effect with respect to a damage | wound may be acquired.
The universal hardness value (HU) and elastic deformation rate are the selection of the material constituting the protective layer, the temperature and irradiation intensity when forming the protective layer such as drying, polymerization and curing, and the protective layer formation. It is possible to adjust the surface protection forming conditions such as the atmosphere in the apparatus to the above range by appropriately adjusting the conditions.
More specifically, for example, in the production example of the photoreceptor A-1 to be described later, for example, by increasing the electron beam irradiation output to the protective layer and increasing the temperature during the heat treatment after the electron beam irradiation, The thickness value (HU) and the elastic deformation rate tend to increase. When only one of the universal hardness value (HU) or the elastic deformation rate is to be changed, it can be adjusted by a known method such as changing the resin material constituting the protective layer or adding an additive to the resin material. .

In the present invention, the universal hardness value (HU) and elastic deformation rate are measured as follows.
The photoreceptor is allowed to stand for 24 hours in an environment of 23 ° C./50% RH, and then the following hardness measurement is performed. Measurement is performed using a microhardness measuring apparatus Fischerscope H100V (Fischer), which continuously applies hardness by applying a load to the indenter and directly reading the indentation depth under the load. As the indenter, a Vickers quadrangular pyramid diamond indenter having a facing angle of 136 ° can be used. Specifically, measurement is performed in stages (273 points with a holding time of 0.1 sec for each point) up to a final load of 6 mN.
In the present invention, the universal hardness value (hereinafter also referred to as HU) can be obtained by the following equation from the indentation depth under the same load when the final load is 6 mN.

The elastic deformation rate is obtained from the amount of work (energy) performed by the indenter with respect to the measurement target (the surface of the photoconductor), that is, the change in energy due to the increase or decrease of the load with respect to the measurement target (the surface of the photoconductor). be able to. Specifically, as shown by the following formula, a value (We / Wt) obtained by dividing the elastic deformation work (We) by the total work (Wt) is the elastic deformation rate.

  On the surface of the photoreceptor used in the present invention, there are 20 or more and less than 1000 grooves having a groove width of 0.5 μm or more and less than 40.0 μm per unit length of 1000 μm in the bus bar direction of the photoreceptor. The sum [μm] of the groove widths W1 to Wi per 1000 μm satisfies the following formula (1).

  The above-mentioned “unit length 1000 μm in the direction of the generatrix of the photosensitive member” refers to a direction of rotation (thrust) of the photosensitive member that is arbitrarily selected on the surface of the photosensitive member 1000 μm.

As described above, the groove width of the groove existing on the surface of the photoreceptor is 0.5 μm or more and less than 40 μm.
Grooves of less than 0.5 μm have problems in measurement accuracy and reproducibility, and since they do not have this function, they are not counted as grooves, and the maximum width of the grooves present on the surface of the photoreceptor may be less than 40 μm. preferable.
In the present invention, the maximum groove width in a groove having a groove width of 0.5 μm or more and less than 40.0 μm present on the surface of the photoreceptor is also referred to as a maximum groove width.
When the maximum groove width is 40 μm or more, in an image forming apparatus having a cleaning blade as a cleaning unit, the tracking performance of the cleaning blade tends to be insufficient, the cleaning performance tends to be slightly deteriorated, and the developer tends to pass through the cleaning blade. is there. Furthermore, since the cleaning property is inferior, the supply of the inorganic fine powder to the groove portion becomes excessive and insufficient, and the effect of preventing the selective chemical deterioration of the groove portion is reduced.
Further, when the number of grooves (groove number density) of the groove having a groove width of 0.5 μm or more and less than 40.0 μm per unit length 1000 μm in the direction of the generatrix on the surface of the photoreceptor is less than 20, In an image forming apparatus having a cleaning blade as a cleaning means, the edge of the cleaning blade is chipped due to an increase in the number of sheets passed, resulting in poor cleaning, and a black streak image is likely to be formed on the image, or melting due to fixing of the developer component. It tends to appear as a white spot image on the image.
On the other hand, in a cleaningless image forming apparatus, there is a possibility that a problem occurs in the press contact portion of the photoreceptor. Specific examples include contamination of the charging unit, chargeability deterioration of the developer in the developing unit, and scratches on the transfer unit.
On the other hand, when the number of grooves (groove number density) of a groove having a groove width of 0.5 μm or more and less than 40.0 μm per unit length of 1000 μm in the bus-bar direction of the photoreceptor existing on the surface of the photoreceptor is 1000 or more Besides, the character reproducibility tends to be inferior, and in particular, in a low humidity environment, there is a tendency that a cleaning failure occurs in which the developer slips through the cleaning blade.
The number of grooves (groove number density) having a groove width of 0.5 μm or more and less than 40.0 μm per unit length of 1000 μm in the bus bar direction of the photoreceptor is preferably 120 or more and less than 720.

  In the surface shape of the photoreceptor, the width of the flat portion (portion where the groove does not exist) is preferably 0.5 μm or more and less than 40 μm. When the width of the flat portion is 40 μm or more, in an image forming apparatus having a cleaning blade as a cleaning means, the torque between the photosensitive member and the blade increases depending on the surface of the photosensitive member, the constituent material of the developer, and various process conditions. It is easy to carry out, and it is easy to produce defective cleaning.

Furthermore, as described above, the total sum of the groove widths W1 to Wi per unit length of 1000 μm is 200 μm or more and 800 μm or less.
When the sum exceeds 800 μm, in the image forming apparatus having a cleaning blade as a cleaning unit, the developer between the photosensitive member and the blade easily slips through, depending on the surface of the photosensitive member, the constituent material of the developer, and various process conditions. A cleaning defect is likely to occur. On the other hand, if the total is smaller than 200 μm, the torque between the photosensitive member and the blade tends to increase, and cleaning failure tends to occur.
The total sum of the groove widths W1 to Wi per unit length of 1000 μm is preferably 370 μm or more and 720 μm or less.

Note that the groove width of the grooves, the number of grooves per unit length of 1000 μm in the generatrix direction of the photoreceptor (groove number density), and the width of the flat portion existing on the surface of the photoreceptor are determined by non-contact three-dimensional surface measurement. The measurement is performed as follows using a machine [trade name: Micromap 557N, manufactured by Ryoka System Co., Ltd.].
A five-fold two-beam interference objective lens is mounted on the optical microscope section of the non-contact three-dimensional surface measuring machine, the photoconductor is fixed under the lens, and the surface shape image is perpendicular to the interference image using a CCD camera in Wave mode. Scan to obtain a three-dimensional image. The range of the obtained image is 1.6 mm × 1.2 mm. The obtained image is analyzed, and the number of grooves and the groove width per unit length of 1000 μm in the bus bar direction of the photoreceptor are obtained as data.
Regarding the groove width and the number of grooves, in addition to the non-contact three-dimensional surface measuring machine, a commercially available laser microscope [VD-8550, VK-9000, Keyence Co., Ltd.], scanning confocal laser Surface image of the photoconductor using a microscope OLS3000 [manufactured by Olympus Co., Ltd.], a real color confocal microscope Oplitex C130 [manufactured by Lasertec Co., Ltd.], a digital microscope VHX-100, VH-8000 [manufactured by Keyence Co., Ltd.], etc. It is also possible to obtain the groove width and the number of grooves using image processing software [for example, WinROOF (manufactured by Mitani Corporation)] based on the above.
Further, if a three-dimensional non-contact shape measuring device [New View 5032 (manufactured by Zygo Co., Ltd.)] or the like is used, it is possible to perform measurement in the same manner as the non-contact three-dimensional surface measuring machine.

  In the present invention, there are 20 or more and less than 1000 grooves each having a groove width of 0.5 μm or more and less than 40.0 μm per 1000 μm unit length in the generatrix direction of the photoreceptor, and each groove width per 1000 μm of the unit length. A photoreceptor in which the total sum [μm] of W1 to Wi satisfies the above formula (1) can be manufactured by the following surface roughening means.

(1) The surface shape of the photoconductor is controlled by physically polishing the surface of the photoconductor.
(2) In the step of applying the photosensitive layer and / or protective layer on the roughened support, the surface shape of the support is maintained up to the surface of the photoconductor.
(3) After applying the photosensitive layer and / or the protective layer, the surface is roughened in a fluid state before drying or curing.

Hereinafter, the means (1) will be described.
An example of a polishing machine including a polishing sheet used for roughening the surface of the photoreceptor is shown in FIG. The polishing sheet 1 is wound around a hollow shaft α, and a motor (not shown) is arranged so that tension is applied to the polishing sheet 1 in the direction opposite to the direction in which the sheet is fed to the shaft α. The polishing sheet 1 is fed in the direction of the arrow, passes through the backup roller 3 through the guide rollers 2-1 and 2-2, and the polished sheet is a motor (not shown) through the guide rollers 2-3 and 2-4. Is wound on the winding means 5. The roughening of the surface of the photoconductor 4 is basically performed by constantly pressing an untreated polishing sheet against the surface of the photoconductor and polishing the surface of the photoconductor with the polishing sheet. Since the polishing sheet 1 is basically insulative, it is preferable to use a grounded part or a conductive part for the part in contact with the sheet.

  Note that the groove shape (groove width, number of grooves, surface roughness, etc.) of the surface of the photoreceptor is, for example, when a polishing sheet is used as the roughening means, the polishing sheet feed speed, and the pack-up roller pressing. It can be adjusted by appropriately selecting the pressure, the particle size and shape of the abrasive grains, the count of the abrasive grains dispersed in the abrasive sheet, the binder resin film thickness of the abrasive sheet, the substrate thickness, and the like.

In the charging step in the image forming method of the present invention, the photosensitive member is charged using a bias applying unit that applies a charging bias in which an AC voltage is superimposed on a DC voltage, and the absolute value discharge current in the longitudinal direction in the charging step. When the value is 100 μA / cm or less, the charging frequency of the AC voltage is f [Hz], and the linear velocity of the photoreceptor is v [mm / sec], it is preferable that the following formula (2) is satisfied.

The charging member used in the charging step is not particularly limited as long as it has a bias applying means for applying a charging bias in which an AC voltage is superimposed on a DC voltage. That is, a system such as a roller, a brush, or a plate type that performs charging by contacting a photoconductor may be used, or a non-contact charging such as corona charging or a system such as injection charging may be used.
Among these, as the charging member, a roller-type contact charging method is more preferable from the viewpoints of reducing the size of the charging device, generating less ozone, and reducing power consumption.
A charging member that employs a roller-type contact charging method generally has a structure in which an intermediate resistance layer having elasticity is provided around a conductive metal core. Moreover, the resistance control layer which adjusts resistance in the said middle resistance layer, the structure which laminated | stacked the surface layer, etc. are taken. Examples of the material of the intermediate resistance layer having elasticity include urethane, SBR, EVA, SBS, SEBS, SIS, TPO, EPDM,
There are resins and rubbers such as EPM, NBR, IR, BR, silicon rubber, epichlorohydrin rubber, etc., depending on the required resistance value, such as carbon black, carbon fiber, metal oxide, metal powder, perchlorate, etc. A conductivity-imparting agent such as a solid electrolyte or a surfactant is added.

As described above, the absolute value discharge current value in the longitudinal direction in the charging step is preferably 100 μA / cm or less, and more preferably 30 μA / cm or more and 90 μA / cm or less. Further, when the charging frequency of the AC voltage is f [Hz] and the linear velocity of the photosensitive member is v [mm / s], it is preferable that the following expression (2) is satisfied, and the following expression (3) is satisfied. More preferably.

If the absolute value discharge current amount is larger than 100 μA / cm, the influence on the chemical deterioration of the photoreceptor surface resin due to the discharge is large, so that the developer tends to be insufficiently inhibited from discharging into the groove portion. The amount of discharge products tends to increase, and removal by cleaning tends to be difficult, and image flow and image density decrease tend to occur.
When the value (f / v) obtained by dividing the charging frequency [f] of the AC voltage by the linear velocity [v] of the photoconductor is 4 or less, the number of times of charging during a certain distance in the circumferential direction of the photoconductor tends to decrease. Yes, it tends to cause uneven charging and insufficient charging. In addition, when (f / v) is 10 or more, the number of discharges tends to increase, and the chemical degradation of the photoreceptor surface resin tends to increase, and the amount of discharge products generated is large, resulting in cleaning. Removal tends to be difficult, and problems such as image flow and image density reduction are likely to occur.

The absolute value discharge current amount is adjusted by adjusting means such as changing the setting of the applied DC or AC voltage or current value, changing the charging frequency, changing the shape of the AC bias waveform, etc. sell. The charging frequency may be set within a preferable range depending on the linear velocity determined by the diameter and rotation speed of the photoconductor used.

  The method for measuring the absolute value discharge current amount in the present invention will be described later.

  Specific examples of the present invention will be described below, but the present invention is not limited to these examples. In addition, the number of parts in the following composition is part by mass unless otherwise specified.

(Production of inorganic fine powder A-1)
The hydrous titanium oxide obtained by hydrolyzing the titanyl sulfate aqueous solution was washed with pure water until the electric conductivity of the filtrate reached 2200 μS / cm. NaOH was added to the hydrous titanium oxide slurry, and the sulfate radical adsorbed was washed with SO ₄ until it became 0.24% by mass. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH of the slurry to 1.0 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was 6.0, and the supernatant was washed by decantation with pure water until the electrical conductivity of the supernatant reached 120 μS / cm. When the obtained hydrous titanium oxide was examined by X-ray diffraction, only the peak of anatase TiO ₂ was shown.
533 g (0.6 mol) of metatitanic acid having a moisture content of 91% obtained as described above was put into a SUS reaction vessel, and nitrogen gas was blown into the vessel and left for 20 minutes to replace the inside of the reaction vessel with nitrogen gas. 183.6 g (0.66 mol) of Sr (OH) ₂ .8H ₂ O (purity 95.5%) was added, and distilled water was further added to add 0.3 mol / liter (SrTiO ₃ conversion), SrO / TiO _2. A slurry with a molar ratio of 1.10 was prepared.
The slurry was heated to 90 ° C. at 18 [° C./1 hour] in a nitrogen atmosphere, and reacted at the boiling point for 2 hours. After the reaction, the reaction solution is cooled to 40 ° C., the supernatant is removed under a nitrogen atmosphere, and decantation is performed twice by adding 2.5 liters of pure water, followed by washing twice, followed by filtration with Nutsche. It was. The obtained cake was dried in the atmosphere at 110 ° C. for 4 hours.
The strontium titanate having a number average particle diameter of 105 nm, a cubic shape and a rectangular parallelepiped shape obtained as described above was designated as inorganic fine powder A-1.

(Production of inorganic fine powder A-2, 3, 4, 5)
In the production of the inorganic fine powder A-1, by adjusting the reaction temperature of strontium titanate, the heating rate up to the temperature, the reaction time, and the pH of the dispersion, the shape has the number average particle diameter shown in Table 1. Cubic and cuboidal perovskite inorganic fine powders A-2, 3, 4, and 5 were produced.

(Production of inorganic fine powder B-1)
1500 g of strontium carbonate and 800 g of titanium oxide were wet-mixed in a ball mill for 8 hours and then filtered and dried. The mixture was molded at a pressure of 5 kg / cm ² and calcined at 1300 ° C. for 8 hours. This was mechanically pulverized and coarse powder and fine powder were simultaneously removed by an Elbow jet classifier utilizing the Coanda effect to obtain strontium titanate (SrTiO ₃ ) having a number average particle diameter of 1010 nm. B-1). Moreover, since it passed through the baking process at high temperature, compared with the inorganic fine powder A, the shape was a polyhedral shape close to a sphere.

(Production of inorganic fine powder B-2, 3, 4, 5)
The classification conditions were adjusted to obtain polyhedral strontium titanates B-2, 3, 4, and 5 having different particle sizes. Table 1 shows the particle size of the obtained inorganic fine powder B.

(Manufacture of photoconductor A-1)
600 parts by mass of powder composed of barium sulfate particles having a tin oxide coating layer (trade name: Pastoran PC1, manufactured by Mitsui Mining & Smelting Co., Ltd.), titanium oxide (trade name: TITANIX JR, manufactured by Teika Co., Ltd.) 150 mass Part, resol type phenolic resin (trade name: Phenolite J-325, manufactured by Dainippon Ink & Chemicals, Inc., solid content 70%) 430 parts by mass, silicone oil (trade name: SH28PA, manufactured by Toray Silicone Co., Ltd.) A solution composed of 0.15 parts by mass, 36 parts by mass of a silicone resin (trade name: Tospearl 120, manufactured by Toshiba Silicone Co., Ltd.), and 500 parts by mass of 2-methoxy-1-propanol / 500 parts by mass of methanol was added for about 20 hours. Dispersion was performed with a ball mill to prepare a conductive layer coating. The conductive layer coating material thus prepared was applied on an aluminum cylinder (outer diameter 30 mm) by an immersion method, and was heated and cured at 150 ° C. for 50 minutes to form a conductive layer having a thickness of 15 μm.

  Next, 10 parts by mass of copolymerized polyamide-based synthetic fiber resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) and methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Teikoku Chemical Co., Ltd.) 30 A film obtained by dissolving a part by mass in a mixed solution of 400 parts by mass of methanol / 200 parts by mass of n-butanol is dip-coated on the conductive layer, heated at 100 ° C. for 20 minutes and dried to obtain a film thickness. An intermediate layer of 0.45 μm was formed.

Next, 20 parts by mass of hydroxygallium phthalocyanine having strong peaks at 7.4 ° and 28.2 ° of the black angle 2θ ± 0.2 ° of CuKα characteristic X-ray diffraction, calixarene compound 0 of the following structural formula (2) 2 parts by weight, 10 parts by weight of polyvinyl butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 600 parts by weight of cyclohexanone were dispersed for 4 hours in a sand mill using glass beads having a diameter of 1 mm, and then 700 parts by weight of ethyl acetate. Part was added to prepare a dispersion for charge generation layer. This was applied onto the intermediate layer by a dip coating method, heated at 80 ° C. for 20 minutes and dried to form a charge generation layer having a thickness of 0.2 μm.

次いで、下記構造式（４）の正孔輸送性化合物４５０質量部、及びポリテトラフルオロエチレン粒子（ダイキン工業製：ルブロンＬ２）５０質量部をｎ−プロピルアルコール８００質量部に混合した後、分散処理を行い、保護層用塗料を調整した。この保護層用塗料を前記電荷輸送層上に塗布した後、大気中５０℃で１０分間乾燥した。

その後窒素中において加速電圧１５０ｋＶ、線量１５ＫＧｙの条件で前記アルミニウムシリンダを回転させながら２秒間電子線照射を行い、引き続いて窒素中において２５℃から１２０℃までおよそ１００秒かけて昇温させ硬化反応を行った。なお電子線照射及び加熱硬化反応中の酸素濃度は１０ｐｐｍであった。その後大気中において、１００℃で３０分の後加熱処理を行って、膜厚５μｍの保護層を形成し、感光体Ａ−１を得た。 Next, 70 parts by mass of a hole transport compound of the following structural formula (3) and 100 parts by mass of a polycarbonate resin (Iupilon Z400: manufactured by Mitsubishi Engineering Plastics) are mixed with 600 parts by mass of monochlorobenzene and 200 parts by mass of methylal. Dissolved in to prepare a charge transport layer coating. The charge transport layer coating material was dip-coated on the charge generation layer, heated at 100 ° C. for 40 minutes, and dried to form a charge transport layer having a thickness of 21 μm.

Next, 450 parts by mass of the hole transporting compound of the following structural formula (4) and 50 parts by mass of polytetrafluoroethylene particles (Daikin Industries: Lubron L2) were mixed with 800 parts by mass of n-propyl alcohol, followed by dispersion treatment. The coating for protective layer was adjusted. This protective layer coating was applied on the charge transport layer and then dried at 50 ° C. for 10 minutes in the air.

Thereafter, electron beam irradiation is performed for 2 seconds while rotating the aluminum cylinder under the conditions of an acceleration voltage of 150 kV and a dose of 15 KGy in nitrogen, and then the temperature is raised from 25 ° C. to 120 ° C. over about 100 seconds in order to cause a curing reaction. went. The oxygen concentration during electron beam irradiation and heat curing reaction was 10 ppm. Thereafter, a post-heat treatment was performed at 100 ° C. for 30 minutes in the air to form a protective layer having a thickness of 5 μm, thereby obtaining a photoreceptor A-1.

(Manufacture of photoconductor A-2)
In the production of the photoreceptor A-1, 450 parts by mass of the hole transporting compound of the structural formula (4) were changed to 300 parts by mass of the hole transporting compound of the structural formula (4) and 150 parts by mass of the acrylic monomer. Produced a photoconductor in the same manner as in the production of photoconductor A-1, and obtained photoconductor A-2.

(Manufacture of photoconductor A-3)
In the production of the photoreceptor A-1, 0 parts by mass of polytetrafluoroethylene particles (manufactured by Daikin Industries: Lubron L2) as a coating material for the protective layer, 750 parts by mass of n-propyl alcohol, and the structural formula (4) Photoreceptor A-1 except that 450 parts by mass of the hole transporting compound was changed to 400 parts by mass of the hole transporting compound of the above structural formula (4) and 50 parts by mass of the acrylic monomer, and the dose 15 KGy was 7.5 KGy. A photoconductor was prepared in the same manner as described above to obtain photoconductor A-3.

(Manufacture of photoconductor A-4)
In the production of the photoreceptor A-1, except that the polytetrafluoroethylene particles (manufactured by Daikin Industries: Lubron L2) as the coating material for the protective layer is 300 parts by mass and the n-propyl alcohol is 700 parts by mass, the photoreceptor A- A photoreceptor was prepared in the same manner as in Example 1 to obtain a photoreceptor A-3.

(Manufacture of photoconductor A-5)
In the same manner as in the production of the photoreceptor A-1, a conductive layer, an intermediate layer, a charge generation layer, and a charge transport layer were formed on an aluminum cylinder. Next, antimony-containing tin oxide fine particles having an average particle size of 0.02 μm (trade name: T-1, manufactured by Mitsubishi Materials Corporation), 100 parts by mass, (3,3,3-trifluoropropyl) trimethoxysilane (Shin-Etsu) (Chemical Co., Ltd.) 30 parts by mass and 95% ethanol-5% aqueous solution 300 parts by mass mixed with a milling device for 1 hour, the dispersed solution is filtered, washed with ethanol and dried, The surface of the antimony-containing tin oxide fine particles was treated by heating at 120 ° C. for 1 hour. Next, 25 parts by mass of a curable acrylic monomer (photopolymerizable monomer) having a structure represented by the following structural formula (5), 5 parts by mass of 2,2-dimethoxy-2-phenylacetophenone (photopolymerization initiator), the above 50 parts by mass of antimony-containing tin oxide fine particles after surface treatment and 300 parts by mass of ethanol were dispersed in a sand mill for 96 hours, and then polytetrafluoroethylene resin particles (trade name: Lubron L-2, Daikin Industries ( Co., Ltd.) 20 parts by mass was added, and the mixture was further dispersed for 8 hours in a sand mill device to prepare a protective layer coating solution.
This protective layer coating solution is applied onto the charge transport layer by dip coating, dried at 50 ° C. for 10 minutes, and then irradiated with UV light having a light intensity of 800 mW / cm ² for 40 seconds with a metal halide lamp, resulting in a film thickness of 3 μm. A protective layer was formed to obtain a photoreceptor A-5.

(Manufacture of photoconductor A-6)
A photoconductor A-6 was obtained in the same manner as the photoconductor A-4 except that the dose of the electron beam was changed to 5 KGy in the manufacture of the photoconductor A-4.

(Manufacture of photoconductor A-7)
A photoconductor A-7 was obtained in the same manner as the photoconductor A-5 except that the light intensity of ultraviolet rays was changed to 1000 mW / cm ² in the manufacture of the photoconductor A-5.

  A hardness test was performed on a part of the obtained photoreceptor, and a universal hardness value (HU) and an elastic deformation rate were measured. The results are shown in Table 2.

(Manufacture of roughened photoreceptor B-1)
In the apparatus shown in FIG. 1 using the produced photoreceptor A-1 as a material, an abrasive sheet (trade name: C-2000 (manufactured by Fuji Photo Film Co., Ltd.)), abrasive grains: Si-C (average particle diameter) : 9 μm), substrate: polyester film (thickness: 75 μm), polishing sheet feed speed: 150 mm / min, photoreceptor rotation speed: 50 rpm, pressing pressure: 3.0 N / m ² , sheet and photoreceptor The rotating direction was the counter direction, and the backup roller had an outer diameter: 4 cm in diameter and Asker C hardness: 40, and the surface was roughened for 150 seconds to prepare Photosensitive Member B-1. Prepared separately for surface shape measurement and actual machine durability examination.When the groove and surface roughness of the surface of the photoconductor B-1 were measured, the groove was measured per unit length of 1000 μm in the bus bar direction of the photoconductor. Width 0.5μm or less The number of upper grooves of less than 40.0 μm was 350, the maximum groove width was 9.5 μm, the ten-point average surface roughness (Rz) was 0.60 μm, and the maximum surface roughness (Rmax) was 0.69 μm.
In addition, the measurement of the groove | channel was performed as follows using the non-contact three-dimensional surface measuring machine (Brand name: Micromap 557N, product made by Ryoka System Co., Ltd.). That is, a five-fold two-beam interference objective lens is mounted on the optical microscope section of the non-contact three-dimensional surface measuring machine, the photosensitive member is fixed under the lens, and the surface shape image is an interference image using a CCD camera in Wave mode. Was scanned vertically to obtain a three-dimensional image of the surface of the photoreceptor. The range of the obtained image is 1.6 [mm] × 1.2 [mm]. In the obtained image, the groove width, the number of grooves having a groove width of 0.5 μm or more and less than 40.0 μm present per unit length of 1000 μm in the photoreceptor thrust (bus line) direction, and the maximum groove width were analyzed. In addition, the groove width of 0.5 μm or more is counted, and the data is analyzed at a total of 12 points, 3 points in the thrust direction of the electrophotographic photosensitive member and 4 points in the circumferential direction in each thrust direction, and the average value of 12 points is obtained. It was.
On the other hand, for the surface roughness, a contact-type surface roughness measuring machine (trade name: Surfcorder SE3500, manufactured by Kosaka Laboratory Ltd.) was used. Detector: R2 [μm], 0.7 mN diamond needle, filter: 2CR, cutoff value: 0.8 mm, measurement length: 2.5 mm, feed rate: 0.1 mm, specified in JIS standard 1982 Data of maximum surface roughness (Rmax) and ten-point average surface roughness (Rz) were obtained. Measurements were made at 12 points in total, 3 points in the thrust direction of the photoreceptor and 4 points in the circumferential direction in each thrust direction, and the average value was obtained.

(Manufacture of roughened photoconductors B-2 to 9 and B-16 to 19)
In the production of the photoreceptor B-1, the polishing conditions were changed, and the photoreceptors B-2 to 9 and B-16 to 19 having surface property numerical parameters shown in Table 3 were produced.

(Manufacture of roughened photoreceptor B-10)
In the production of the photoconductor B-1, a photoconductor was prepared in the same manner as the photoconductor B-1 except that the photoconductor A-2 was used instead of the photoconductor A-1, and the photoconductor B-1 was produced. -10 was obtained.

(Manufacture of roughened photoreceptor B-11)
In the production of the photoconductor B-1, a photoconductor was prepared in the same manner as the photoconductor B-1 except that the photoconductor A-3 was used instead of the photoconductor A-1, and an electrophotographic photosensitive member was produced. Body B-11 was obtained.

(Manufacture of roughened photoreceptor B-12)
In the production of the photoconductor B-1, a photoconductor was prepared in the same manner as the photoconductor B-1 except that the photoconductor A-4 was used instead of the photoconductor A-1, and an electrophotographic photosensitive member was produced. Body B-12 was obtained.

(Manufacture of roughened photoreceptor B-13)
In the production of the photoconductor B-1, a photoconductor was prepared in the same manner as the photoconductor B-1 except that the photoconductor A-5 was used instead of the photoconductor A-1, and an electrophotographic photosensitive member was produced. Body B-13 was obtained.

(Manufacture of roughened photoreceptor B-14)
In the production of the photoconductor B-1, a photoconductor was prepared in the same manner as the photoconductor B-1 except that the photoconductor A-6 was used instead of the photoconductor A-1, and an electrophotographic photosensitive member was produced. Body B-14 was obtained.

(Manufacture of roughened photoreceptor B-15)
In the production of the photoconductor B-1, a photoconductor was produced in the same manner as the photoconductor B-1 except that the photoconductor A-7 was used instead of the photoconductor A-1, and an electrophotographic photosensitive member was produced. Body B-15 was obtained.

The maximum groove width, the number density of grooves, the total width of each groove calculated from the above formula (1), the ten-point average surface roughness (Rz), and the maximum surface roughness (Rmax). Table 3 shows the surface property numerical parameters.

[Examples of resin production]
(Hybrid resin)
(1) Manufacture of polyester resin, terephthalic acid: 6.2 mol
・ Dodecenyl succinic anhydride: 3.7 mol
-Trimellitic anhydride: 3.3 mol
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane (PO-BPA): 7.4 mol
・ Polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
(EO-BPA): 3.0 mol
The above polyester monomer is charged into an autoclave together with an esterification catalyst, and a polycondensation reaction is performed while heating to 215 ° C. in a nitrogen gas atmosphere with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device. A polyester resin was obtained.
(2) Production of Hybrid Resin 80 parts by mass of the polyester resin was dissolved and swollen in 100 parts by mass of xylene. Next, 15 parts by mass of styrene, 5 parts by mass of 2-ethylhexyl acrylate, and 0.15 parts by mass of dibutyltin oxide as an esterification catalyst were added and heated to the reflux temperature of xylene. The transesterification reaction with ethylhexyl was started. Further, a xylene solution in which 1 part by mass of t-butyl hydroperoxide was dissolved in 30 parts by mass of xylene as a radical polymerization initiator was dropped over about 1 hour. The radical polymerization reaction was completed by holding at that temperature for 6 hours. Acrylic acid 2 which is a copolymerization monomer of hydroxyl group of polyester resin and vinyl polymer unit by heating to 200 ° C. under reduced pressure to remove the solvent
-A transesterification reaction with ethylhexyl was carried out, whereby a polyester resin, a vinyl polymer, and a hybrid resin 1 produced by ester bonding of the polyester unit and the vinyl polymer unit were obtained.
The obtained hybrid resin 1 has an acid value of 28.5 mgKOH / g, a glass transition temperature (Tg) of 58 ° C., a peak molecular weight (Mn) of 7400, a weight average molecular weight (Mw) of 45000, Mw / Mn was 8.3 and contained about 12% by mass of THF-insoluble matter.

[Toner Production Example 1]
-100 parts by mass of the above hybrid resin 1-7 parts by mass of low molecular weight ethylene-propylene copolymer (endothermic main peak temperature: 86 ° C, exothermic main peak temperature: 86.5 ° C)
Charge control agent (azo-based iron complex compound) 2 parts by mass (made by Hodogaya Chemical Co., Ltd., trade name T-77)
・ 90 parts by mass of magnetic iron oxide (average particle size is 0.19 μm, coercive force is 11.2 KA / m, remanent magnetization is 10.8 Am ² / kg, saturation magnetization is 82.3 Am ² / kg)
The above mixture was melt-kneaded with a twin-screw kneader heated to 130 ° C., and the cooled mixture was coarsely pulverized with a hammer mill. Further, the pulverization process uses a mechanical pulverizer (Turbo Kogyo Co., Ltd.) turbo mill T-250 type, the gap between the rotor and the stator is 1.5 mm, the tip peripheral speed of the rotor is 115 m / sec, and the conveying air flow rate Was operated at 30 m ³ / h and the supply of the coarsely crushed product was 24 kg / h.
The obtained finely pulverized product was classified with an air classifier to obtain toner particles in which particles having a weight average particle diameter of 7.8 μm, 10.1 μm or more were 6.3% by volume.
With respect to 100 parts by mass of the toner particles, 1.0 part by mass of the inorganic fine powder B-1 and 1.0 part by mass of hydrophobic dry silica (BET specific surface area: 300 m ² / g) It stopped by rotating for 2 minutes with the Henschel mixer FM500 (made by Mitsui Miike) of speed 1100rpm. To this, 0.5 (part by mass) of inorganic fine powder A-1 was additionally charged, and further rotated for 2 minutes and externally added to obtain toner 1. In the obtained toner, the release rate α (A) of the inorganic fine powder A from the toner particles and the release rate α (B) of the inorganic fine powder B from the toner particles were measured. The results are shown in Table 5.

[Toner Production Examples 2 to 18, and 20 to 23]
The inorganic fine powders A-1 to A-5 and the inorganic fine powders B-1 to B-5 shown in Table 4 are used in the usage amounts shown in Table 4, and as shown in Table 5, the mixing time of the external addition and the addition to the external addition Toners 2 to 18 and 20 to 23 were obtained in the same manner as in Toner Production Example 1 except that the timing was changed. In the obtained toner, the release rate α (A) of the inorganic fine powder A from the toner particles and the release rate α (B) of the inorganic fine powder B from the toner particles were measured. The results are shown in Table 5.

[Toner Production Example 19]
630 parts by mass of ion-exchanged water and 485 parts by mass of a 0.1 mol / L Na ₃ PO ₄ aqueous solution were added to a 2 L four-necked flask equipped with a high-speed stirrer CLEARMIX (manufactured by M Technique Co., Ltd.). Then, the rotation speed of CLEARMIX was set to 14,000 rpm and heated to 65 ° C. Here, 65 parts by mass of a 1.0 mol / L CaCl ₂ aqueous solution was gradually added, and further 10% hydrochloric acid was added dropwise thereto, and pH containing a minute hardly water-soluble dispersant Ca ₃ (PO ₄ ) ₂ = 5.8. An aqueous dispersion medium was prepared.
-Styrene monomer 180 parts by mass-n-Butyl acrylate monomer 20 parts by mass-Carbon black 25 parts by mass-3,5-di-tert-butylsalicylic acid aluminum compound 1.3 parts by mass A mixture was prepared by dispersing the mixture for 5 hours, and then the following components were added to the mixture and further dispersed for 2 hours to prepare a monomer mixture.
・ Saturated polyester resin (monomer composition: polycondensation product of propylene oxide modified bisphenol A and terephthalic acid)
(Acid value 8.8 mg KOH / g, peak molecular weight 12,500, weight average molecular weight 19500)
12 parts by mass / ester wax (composition: behenyl behenate, molecular weight 11500) 20 parts by mass Next, 5 parts by mass of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) is added to the monomer mixture. Then, after preparing a polymerizable monomer composition, it was put into an aqueous dispersion medium and granulated at 15,000 rpm for 15 minutes in a nitrogen atmosphere with an internal temperature of 70 ° C. Thereafter, the stirrer was replaced with a propeller stirrer, polymerization was performed for 5 hours while maintaining at 70 ° C. while stirring at 50 rpm, and the internal temperature was raised to 80 ° C. for polymerization for 5 hours. After the polymerization was completed, the slurry was cooled and diluted hydrochloric acid was added to remove the dispersant. Further, it was washed with water, dried and classified to obtain toner particles having a weight average particle diameter of 6.8 μm.
With respect to 100 parts by mass of the toner particles, 1.0 part by mass of the inorganic fine powder B-1 and 1.0 part by mass of hydrophobic dry silica (BET specific surface area: 300 [m ² / g]) Stop by rotating for 2 minutes with a Henschel mixer FM500 (Mitsui Miike Co., Ltd.) with a stirring blade rotation speed of 1000 rpm, add 0.5 parts by mass of inorganic fine powder A-1, and rotate for another 2 minutes. Toner 19 was obtained. In the obtained toner, the release rate α (A) of the inorganic fine powder A from the toner particles and the release rate α (B) of the inorganic fine powder B from the toner particles were measured. The results are shown in Table 5.

[Example 1]
In Example 1, the photoreceptor B-1 and the toner 1 were used. In addition, as an image forming apparatus, a Canon laser beam printer MF7240 with a process speed modified to 230 mm / sec and a variable bias power supply attached to contact roller charging is used. An AC voltage was superimposed on the voltage −720V. The waveform of the AC voltage was a sine wave, the frequency was 1350 Hz, and the AC voltage Vpp was set so that the absolute discharge current value was 70 μA / cm.
The absolute discharge current value is calculated by first measuring the total current flowing between the charging member to which the charging bias is applied and the photosensitive member under the above-described conditions. This result is graphed and first-order approximation is performed at a voltage below the region where discharge occurs. The absolute discharge current value was obtained by subtracting the fitted straight line from the total current curve.
Under the conditions described above, a 500,000 sheet-passing test is performed on A4 paper using a chart with a printing ratio of 6% under an environment of 15 ° C./10% RH, and the presence / absence of image scratches is confirmed, and the image is cleaned. (CLN) sex evaluation and image density evaluation were performed. The ranking was made in 5 stages, and it was judged as passing at rank 3 or higher. The paper passing durability was set to an intermittent mode that stopped once for each printed sheet. The evaluation results are shown in Table 6 together with confirmation of the presence or absence of other image defects.
Further, in a 33 ° C./90% RH environment, using a chart with a printing ratio of 6%, a 30,000 sheet passing test was performed on A4 paper, and the presence or absence of image flow was confirmed. The paper passing durability was set to an intermittent mode that stopped once for each printed sheet. The evaluation results are shown in Table 6.

[Image scratch evaluation rank]
Rank 5: No scratches Rank 4: There are 1 or 2 minor scratches Rank 3: Some minor scratches Rank 2: There are several scratches Rank 1: There are scratches on the entire surface

[CLN evaluation rank]
Rank 5: No CLN defect Rank 4: Very minor CLN defect Rank 3: Minor CLN defect Rank 2: Partial CLN defect Rank 1: CLN defect on the entire surface

[Image density evaluation rank]
Rank 5: Reflection density 1.40 or more Rank 4: Reflection density 1.35 to 39 or more Rank 3: Reflection density 1.30 to 34 or more Rank 2: Reflection density 1.25 to 1.29
Rank 1: Reflection density 1.24 or less Note that the reflection density is measured using a Macbeth densitometer (manufactured by Macbeth), which is a reflection densitometer, using an SPI filter and reflecting a 5 mm square solid black image. The concentration was measured and calculated as an average of 5 points.

[Image flow evaluation rank]
Rank 5: No image flow Rank 4: Very slight image flow Rank 3: Small image flow Rank 2: Partial image flow Rank 1: Image flow across the entire surface

[Examples 2 to 17, 21 to 30, 38, and 39, and Comparative Examples 1 to 12]
Evaluations were made in the same manner as in Example 1 using the photoreceptors B-1 to B-19 and the toners 1 to 23 in the combinations shown in Table 6. The evaluation results are shown in Table 6.

[Examples 18 to 20, and 31 to 37]
Evaluation was performed in the same manner as in Example 1 except that the charging frequency and the absolute discharge current value were changed as shown in Table 7 using the photoreceptor B-1 and the toner 1. Table 7 shows the evaluation results.

FIG. 2 is a schematic view of roughening means for roughening the photoreceptor used in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polishing sheet 2-1 Guide roller 2-2 Guide roller 2-3 Guide roller 2-4 Guide roller 3 Backup roller 4 Photoreceptor 5 Winding means α Hollow shaft

Claims (3)

A charging step of charging a photosensitive member having a photosensitive layer on a conductive support, and a developing step of forming an electrostatic latent image on the charged photosensitive member and transferring the developer to the electrostatic latent image for visualization. An image forming method comprising:
On the surface of the photoreceptor, there are 20 or more and less than 1000 grooves having a groove width of 0.5 μm or more and less than 40.0 μm per unit length of 1000 μm in the bus bar direction of the photoreceptor, and the unit length per 1000 μm. The sum [μm] of the groove widths W1 to Wi satisfies the following formula (1),
The developer includes toner particles containing at least a binder resin and a colorant, inorganic fine powder A having a number average particle diameter of 80 nm or more and less than 300 nm, and inorganic fine powder B having a number average particle diameter of 500 nm or more and less than 2000 nm. A developer containing,
The free rate α (A) of the inorganic fine powder A from the toner particles is 20.0% by mass or more and less than 40.0% by mass,
The image forming method, wherein the inorganic fine powder B has a liberation rate α (B) from toner particles of 50.0% by mass or more and less than 75.0% by mass.

In the charging step, the photosensitive member is charged using a bias applying unit that applies a charging bias in which an AC voltage is superimposed on a DC voltage, and an absolute value discharge current value in the longitudinal direction in the charging step is 100 μA / cm or less. The following equation (2) is satisfied when the charging frequency of the AC voltage is f [Hz] and the linear velocity of the photosensitive member is v [mm / sec]: The image forming method described.

The universal hardness value of the surface of the photoconductor is 150 N / mm ² or more and less than 240 N / mm ² , and the elastic deformation rate of the surface of the photoconductor is 44% or more and less than 65%. The image forming method according to claim 1 or 2.

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