Abstract: A control unit performs control to make a direction of an electric field generated in a first area of an image carrier forming a transfer portion during image forming operation, relative to a voltage applied to a brush member in a state where the first area passes through a contact portion, different from a direction of an electric field generated in a second area of the image carrier forming the contact portion, relative to the voltage applied to the brush member during a period when operation is shifted from first operation in which the image carrier is rotated at a first speed to second operation in which the image carrier is rotated at a second speed different from the first speed, during non-image forming operation different from the image forming operation.

Abstract: A toner comprising a toner particle comprising a binder resin and an azo dye, wherein the binder resin comprises a polymer A, the polymer A is a polymer having a monomer unit derived from methacrylonitrile, and a relationship among an amount of substance (mol) of the monomer unit derived from methacrylonitrile, an amount of substance (mol) of the azo dye, and the number of azo groups in the azo dye in the toner particle satisfies formula below: [(amount of substance of azo dye (mol))×(number of azo groups in azo dye)/(amount of substance of monomer unit derived from methacrylonitrile (mol))]?0.500.

Abstract: A toner including a toner particle including a binder resin, wherein fine particles A and B are present on a surface of the toner particle; the fine particles A are a fatty acid metal salt; the fine particles B have a specific volume resistivity; an average theoretical surface area of the toner particle, an amount of the fine particles A, and a coverage ratio of the toner particle surface by the fine particles A satisfy a specific relationship; the amount of the fine particles B is in a specific range; and a proportion F of an area occupied by a part of the fine particles B embedded in a surface vicinity region of the toner in a total area occupied by the fine particles B present in a cross section of one particle of the toner is 50% by area or more.

Abstract: A toner comprising a toner particle, wherein the toner particle includes a binder resin, where a volume resistivity ?·cm of an unfixed solid image on a recording material on which the solid image has been formed using the toner at a toner laid-on level of 0.4 mg/cm2 is denoted by Tv, and a volume resistivity ?·cm of the solid image after fixing by applying heat and pressure to the recording material is denoted by Fv, Tv/Fv?8 is satisfied.

Abstract: A toner containing a toner particle, in which the toner particle contains a binder resin and a pigment, and As and Al satisfy a specific relation, in a case when the toner is divided into two groups i.e. a first group and a second group with an inertial classifier, the first group including a larger size of the toner particles, and the second group including a smaller size of the toner particles, and the number of the toner particles in the first group being substantially equal to the number of the toner particles in the second group. Each of As and Al is a change rate of a surface potential of a pellet type molded product obtained by molding each of the toner in the first group and the toner in the second group under specific conditions is observed using a surface potentiometer under a specific conditions.

Abstract: Herein is disclosed an electrostatic ink composition. In some examples, the electrostatic ink compositions comprise: a carrier liquid; a resin; and a phosphorescent pigment.

Abstract: A toner for electrostatic charge image development includes toner base particles including at least a binder resin, has a volume resistivity of 1.0×1014 ?·cm or more at 25° C. with 50% RH by a temperature change method, and has a volume resistivity of 1.0×1015 ?·cm or less at 67° C. by the temperature change method.

Abstract: Herein is disclosed an electrostatic ink composition comprising a resin and a conductive pigment, wherein the resin comprises a co-polymer formed from an alkylene monomer, an acrylic ester monomer and a maleic anhydride monomer, wherein, in some examples, the acrylic ester monomer constitutes at least about 8 wt % of the co-polymer. Herein is also disclosed a print substrate having printed thereon an electrostatic ink comprising a resin and a conductive pigment, wherein the resin comprises a co-polymer formed from an alkylene monomer, an acrylic ester monomer and a maleic anhydride monomer, wherein, in some examples, the acrylic ester monomer constitutes at least about 8 wt % of the co-polymer.

Abstract: The present invention provides an image of high image quality by using a magnetic carrier coated with a novel coating resin composition. Further, the present invention stably provides a good image which is hardly influenced by environmental fluctuation and long-term use and has a superior stability of a charging amount when left to stand especially under high temperature and high humidity environments. The present invention also provides a magnetic carrier characterized in that a carrier core surface is coated with a copolymer containing at least, as copolymerization components, an acrylic monomer having a specific structure and an acrylic macromonomer having a specific structure.

Abstract: Provided is a magnetic carrier excellent in leakage, uniformity of a solid image having satisfactory charging stability and developing performance at low electric field. The magnetic carrier is a magnetic carrier comprising: a magnetic substance-dispersed resin carrier core, which contains a magnetic substance and a binding resin, and a coating resin on a surface thereof, wherein: the carrier core has resistivity at 1000 V/cm of 5.0×106-8.0×107 ?·cm, the magnetic substance has a number average particle diameter of 0.20-0.35 ?m; and comprises magnetic-substance particles having vertexes and a particle diameter of 0.53 ?m or more in an amount of 10.0-32.0 vol % based on a total amount of the magnetic substance; and wherein: the carrier core has Fe2O3 content of 98.00% by mass or more; and ZnO content of 0.06-0.50% by mass.

Abstract: Employment of a carrier core material for an electrophotographic developer containing 0.8 to 5% by weight of Mg, 0.1 to 1.5% by weight of Ti, 60 to 70% by weight of Fe and 0.2 to 2.5% by weight of Sr and having an amount of Sr dissolved with a pH4 standard solution of 80 to 1000 ppm, a carrier using the core material and a process for producing them, and an electrophotographic developer using the carrier.

Abstract: A developer, including a toner including a binder resin comprising a crystalline resin; and a colorant, and a resin carrier comprising a resin; a magnetic particulate material having a magnetic anisotropy, dispersed in the resin, and having a saturated magnetization of from 16 to 30 emu/g, a coercive force of from 15 to 40 kA/m and an average particle diameter not less than 15 ?m and less than 100 ?m.

Abstract: A toner including: a base resin; and charge-controlling resin particles contained in the base resin, wherein the toner is in shape of particles, and the charge-controlling resin particles are present in a region of each toner particle which is 500 nm in depth from a surface of the toner particle and an average of amounts of the charge-controlling resin particles present in the regions of the toner particles is 20% by volume to 70% by volume, wherein an average of embedment rates of the charge-controlling resin particles in the toner particles is 90% or higher, where each embedment rate is an average of embedment rates of the charge-controlling resin particles in each toner particle, and wherein the charge-controlling resin particles have a charge amount of 60 ?C/m2 or more as measured by a blow-off method.

Abstract: A carrier for a two-component developer, includes: magnetic particles and a resin coating layer that is coated on the magnetic particles, the resin coating layer containing metal nitride particles having a volume average primary particle diameter of from about 300 to about 2,000 nm.

Abstract: A carrier for developing an electrostatic image, includes: magnetic core material particles and a coated layer coated on the magnetic core material particles, the coated layer containing a resin having a monomer unit represented by formula (A): wherein R1 represents a hydrogen atom or a methyl group; R2 to R4 each independently represent a hydrogen atom, an alkyl group, an aryl group or an aralkyl group; R5 independently represents an alkyl group, an aryl group or an aralkyl group; n represents an integer of from 0 to 7; and L1 represents a single bond or an alkylene group, provided that at least one of R3 and R4 is not a hydrogen atom.

Abstract: The present invention relates to a crystalline resin for toners which includes a composite resin including a polycondensation-based resin component obtained by polycondensing an alcohol component containing an aliphatic diol having 2 to 10 carbon atoms with a carboxylic acid component containing an aromatic dicarboxylic acid, and a styrene-based resin component; a resin binder containing the crystalline resin and a non-crystalline resin; and a toner for electrophotography which contains the resin binder. According to the present invention, there are provided a crystalline resin for toners which is capable of producing a toner that is excellent in not only low-temperature fixing ability but also gloss of images and anti-filming property, a resin binder, and a toner for electrophotography.

Abstract: A carrier for developing an electrostatic latent image, including a particulate core material having a magnetism having developed spontaneous magnetization; and a covering layer comprising an electroconductive material, covering the surface of the particulate core material, wherein the carrier has an electrical resistivity Log R [?cm] of from 8.0 to 12.0 when measured by a method, including filling the carrier in a cell containing a pair of facing electrodes, each having a surface area of 2×4 [cm2] with a gap of 2 [mm] therebetween; and applying a DC voltage of 1,000 [V] therebetween to measure a DC resistivity, and a weight-average particle diameter (Dw) of from 25 to 45 ?m.

Abstract: A porous ferrite core material for an electrophotographic developer, the porous ferrite core material including Mg in a content of 0.3 to 3% by weight, Ti in a content of 0.4 to 3% by weight and Fe in a content of 60 to 70% by weight, and the porous ferrite core material having a pore volume of 0.04 to 0.16 ml/g, a peak pore size of 0.4 to 1.6 ?m, a saturation magnetization of 40 to 80 Am2/kg, a remanent magnetization of less than 7 Am2/kg and a coercive force of less than 43 A/m; a resin-filled ferrite carrier for an electrophotographic developer obtained by filling a resin in the voids of the porous ferrite core material; and an electrophotographic developer using the ferrite carrier.

Abstract: An object of the present invention is to provide a carrier containing core material particles having magnetism and a coating layer on the surfaces of the core material particles, wherein the core material particles have a magnetization at a magnetic field of 1,000 Oersted of 40 emu/g to 100 emu/g, and the carrier has a weight average particle diameter of 20 ?m to 45 ?m, a resistance (Log R) of 11 ?·cm to 17 ?·cm and a relaxation time ? of 150 seconds to 800 seconds.

Abstract: The present invention provides a carrier core material for use in the production of an electrophotographic developer which, even when applied, for example, to MFPs (multifunction printers), can realize stable, high-quality and high-speed development, and has a prolonged replacing life of magnetic carriers, and a method of manufacturing the same, a magnetic carrier including the carrier core material, and an electrophotographic developer manufactured from the magnetic carrier. An electrophotographic development carrier is prepared by adding resin particles, a binder, a dispersant, a wetting agent, and water to a raw material powder, wet pulverizing the mixture, drying the pulverized product to give granulated powder, calcinatng the granulated powder, and then sintering the granulated powder to prepare a carrier core material having an internally hollow structure, and coating the carrier core material with a resin.

Abstract: A ferrite core material for a resin-filled type carrier, and a resin-filled type carrier which is used as an electrophotographic developer by mixing a toner, sufficiently secure the image density, have no carrier adhesion and can maintain high-quality images over a long period, and an electrophotographic developer using the carrier, are provided. A ferrite core material for a resin-filled type carrier characterized in a void fraction of 10 to 60%, a resin-filled type carrier filled in the carrier core material with a resin, and an electrophotographic developer composed of the resin-filled type carrier and a toner, are provided.

Abstract: An anisotropic magnetic material-dispersed resin carrier including: fine magnetic particles; and a binder resin in which at least the fine magnetic particles are dispersed, wherein the anisotropic magnetic material-dispersed resin carrier has a magnetic anisotropy where magnetic fields of the fine magnetic particles are orientated in the same direction, and wherein the anisotropic magnetic material-dispersed resin carrier has a saturation magnetization of 16 emu/g to 30 emu/g, a coercive force of 15 kA/m to 40 kA/m, and a number average particle diameter of 15 ?m or more but less than 100 ?m.

Abstract: To provide a carrier for electrophotographic developer, capable of realizing a high image quality and full colorization and reducing carrier scattering, and a manufacturing method of the same, and an electrophotographic developer containing the carrier. A carrier core material for electrophotographic developer, with a general formula expressed by MgxMn(1-x)FeyO4 (where 0<x<1, and 1.6?y?2.4), wherein a half-value width B of a peak having a maximum intensity in a powder XRD pattern satisfies B?0.180 (degree), is manufactured and from this carrier core material for electrophotographic developer, the carrier for electrophotographic developer and the electrophotographic developer are manufactured.

Abstract: Provided is a magnetic toner capable of preventing electrostatic offset while attaining a high image quality by a high speed machine. The magnetic toner comprises magnetic toner particles, each of which contains a binder resin and a magnetic material, and a fine inorganic powder, in which the binder resin contains a polyester unit, and the magnetic toner has a dielectric loss factor at 40° C. and 100 kHz of 0.40 pF/m or more but 1.00 pF/m or less and a dielectric loss factor at 150° C. and 100 kHz of 0.50 pF/m or more but 4.00 pF/m or less.

Abstract: An electrostatic image developing carrier including at least a core material and a coating resin layer which coats the surface of the core material, the resin layer comprising a thermoplastic resin having an alicyclic group, a thermal reduction in accordance with the TGA method being in the range of 0.5 weight % to 5 weight % of the whole of the carrier in the range of 100° C. to 400° C., and further an endothermic quantity of the whole of the carrier in accordance with the DTA method is in the range of 7 mJ/g to 40 mJ/g in the range of 100° C. to 400° C.

Abstract: Provided is a magnetic toner capable of providing a stable image by suppressing sleeve contamination even under a high-temperature and high-humidity environment and under a normal-temperature and low-humidity environment and further suppressing large-particle fogging caused after the toner is left alone for a week. The magnetic toner contains toner particles, each of which contains a binder resin and a magnetic iron oxide particle, in which the binder resin has a polyester unit, the toner has i) a dielectric loss factor at 40° C. and 100 kHz of 0.50 pF/m or more but 0.90 pF/m or less, and ii) a true specific gravity of 1.50 g/cm3 or more but 1.85 g/cm3 or less.

Abstract: Disclosed are a resin-filled ferrite carrier core material for an electrophotographic developer, including a porous ferrite particle, wherein the composition of the porous ferrite particle is represented by the following formula (1), and part of (MgO) and/or (Fe2O3) in the following formula (1) is replaced with SrO; a ferrite carrier obtained by filling a resin in the voids of the ferrite carrier core material; and an electrophotographic developer using the ferrite carrier: ( MgO ) ? x ? ( Fe 2 ? O 3 ) ? y ? ( x = 10 ? ? mol ? ? % ? ? or ? ? more ? ? and ? ? less ? ? than ? ? 25 ? ? mol ? ? % y = exceeding ? ? 75 ? ? mol ? ? % ? ? and ? ? 90 ? ? mol ? ? % ? ? or ? ? less x + y = 100 ? ? mol ? ? % ) .

Abstract: To solve a thin image density and sweeping occurring when a toner carrying member having a small diameter is used, provided is an image-forming method including: a charging step; an electrostatic latent image-forming step; a developing step; a transferring step; and a fixing step, in which a magnetic toner to be used in the method has a specific weight average particle diameter (D4); the magnetic toner has a specific intensity of magnetization in a specific magnetic field; and a surface free energy of a surface of the magnetic toner and a surface free energy of a surface of a toner carrying member to be used in the method satisfy specific relationships.

Abstract: A manufacturing apparatus provided with a rotary stirring section and a powder passage is used to manufacture the resin-layer coated carrier. At a fine resin particle adhering step, a magnetic base particle and a fine resin particle are inputted into the powder passage with the rotary stirring section rotating and the fine resin particle is adhered onto the surface of the magnetic base particle. At a spraying step, at least a liquid that plasticizes the fine resin particles is sprayed with spray gas from a spraying section on the magnetic base particle and the fine resin particle which are in a fluidized state in the powder passage. At a film-forming step, rotation by the rotary stirring section is continued to fluidize the magnetic base particles and the fine resin particles until the fine resin particles adhered to the magnetic base particles are softened to form a film.

Abstract: Method for producing structured particles specifically nanoparticles, toners for laser printers and photocopiers, particularly chemical toner with particular product properties. The method produces toners of improved performance. Method relates particularly to the selection and properties of the base materials and utilizing these properties to design the toner product properties that result in improved performance.

Abstract: A method for producing a carrier, including a step of periodically forming and discharging liquid droplets of a carrier core composition liquid from a plurality of nozzles formed in a thin film, using a liquid droplet forming unit having the thin film and a ring-shaped vibration generating unit disposed in a deformable area of the thin film so as to be along a circumference of the area and to vibrate the thin film, a step of forming carrier core particles by solidifying the discharged liquid droplets, and a step of coating the carrier core particles with a resin layer.

Abstract: The present disclosure provides carriers for use with toner compositions. In embodiments, a carrier may include a core, having a dry powder polymer coating. In embodiments, the coating may also include a colorant, such as carbon black. Processes for coating such carriers with the dry powder polymer coatings are also provided.

Abstract: In a method for coating electrophotographic carrier core surfaces with a resin composition by rotating a rotator having a plurality of agitating blades on its surface in a casing; a coating treatment material that is introduced to a space defined between the rotator and the casing is in a packing of from 50% to 98% by volume; at the time of coating treatment, the electrophotographic carrier core surfaces are coat-treated with the resin composition while being put forward and put backward; and the electrophotographic carrier cores and the resin composition are, at the time of coating treatment, temperature-controlled at a specific temperature T (° C.) or below. This method enables the electrophotographic carrier core surfaces to be more uniformly coated with a coating resin.

Abstract: An image forming apparatus including at least an image bearer; a charger charging the image bearer; an irradiator irradiating the image bearer to form an electrostatic latent image thereon; an image developer developing the electrostatic latent image with a developer comprising a toner and a carrier to form a toner image on the image bearer; a developer feeder feeding a supplemental developer including the toner and the carrier into the image developer; and a developer collector collecting the developer in the image developer, wherein the developer feeder includes a cylindrical supplemental developer container containing the supplemental developer, including a spiral developer guide race on the inner circumferential surface thereof; and a sub-hopper configured to store the supplemental developer, and wherein the carrier includes a core material; and a layer coated on the core material, including a binder resin and non-black or a non-color inorganic particulate material.

Abstract: A toner including stabilized magnetic single-crystal nanoparticles, wherein the value of the magnetic anisotropy of the magnetic nanoparticles is greater than or equal to 2×104 J/m3. The magnetic nanoparticle may be a ferromagnetic nanoparticle, such as FePt. The toner includes a magnetic material that minimizes the size of the particle, resulting in excellent magnetic pigment dispersion and dispersion stability, particularly in emulsion/aggregation toner processes. The smaller sized magnetic particles of the toner also maintains excellent magnetic properties, thereby reducing the amount of magnetic particle loading required in the toner.

Abstract: A magnetic carrier is provided which uses a toner having high coloring power and enables development to be performed at low electric field intensity and can form high quality images while keeping gradation characteristics. The magnetic carrier includes magnetic carrier particles including at least porous magnetic core particles and a resin. The electric field intensity just before the break-down of the magnetic carrier is 1,300 V/cm or more and 5,000 V/cm or less.

Abstract: A two-component developer containing a yellow toner and a magnetic carrier, wherein the yellow toner has the characteristics: (i) when the concentration of the yellow toner in a solution of the yellow toner in chloroform is represented by Cy (mg/ml) and the absorbance of the solution at a wavelength of 422 nm is represented by A422, a relationship between Cy and A422 satisfies the relationship of 6.00<A422/Cy<14.40; (ii) the lightness L* and chroma C* of the yellow toner determined in a powder state satisfy the relationships of 85.0?L*?95.0 and 100.0?C*?115.0; and (iii) the absolute value for the triboelectric charge quantity of the yellow toner measured by a two-component method using the yellow toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less.

Abstract: An electrophotographic developer including: magnetic particles, and a toner containing toner particles charged with the magnetic particles and having a particle diameter distribution, wherein the toner exhibits cumulative toner weight distributions of both square of charge amount q2 [C2] and attachment force F [N] per particle with respect to a representative toner particle diameter in the particle diameter distribution, giving a linear approximation of plots of the attachment force F [N] versus the square of charge amount q2 [C2] per particle at a plurality of corresponding cumulative toner weight ratios, and the linear approximation satisfies a slope of the linear approximation of from 5×1020 to 3×1022 and a squared multiple correlation coefficient (R2) of 0.6 or more. As a result, the developer allows good control of transferability under the control of an electric field and allows a reduction in transfer residual amount of the toner.

Abstract: An electrostatic latent image developing carrier is provided which comprises a core particle and a resin coating layer containing conductive particles dispersed therein, the carrier having a volume average particle diameter of 25 to 60 ?m and an average degree of circularity of 0.975 or more, wherein the core particle has a BET specific surface area of 0.1 to 0.3 m2/g and an internal void ratio of 10% or less.

Abstract: A toner having a crystalline or semi-crystalline polyester resin, an amorphous resin and a colorant. The toner preferably exhibits a resistivity of at least 1×1011 ohm-cm. A developer may be produced including the toner and optionally a carrier. If a carrier is included, the carrier preferably exhibits a resistivity of greater than 1×107 ohm-cm. An electrophotographic machine includes the toner exhibiting high resistivity.

Abstract: A toner for electrostatic latent image development is disclosed, comprising colored particles containing a binder resin and a colorant, and an external-additive, wherein the external additive comprises boron nitride particles exhibiting a number average primary particle size of 10 to 500 nm. The production method of the toner is also disclosed.

Abstract: There are adopted an electrophotographic resin-coated ferrite carrier having a carrier core coated with a resin, wherein a product of an apparent density ? (g/cm3), average particle size d (?m) and BET specific surface area S (m2/g) of the carrier core satisfies the following condition, a method for producing the same, and an electrophotographic developer. 4.5??×d×S?8.

Abstract: A magnetic toner is disclosed having magnetic toner particles containing a binder resin and a magnetic iron oxide. The magnetic toner has a specific saturation magnetization and a specific residual magnetization in ascertain magnetic field. The binder resin includes a polyester component polymerized with an aromatic carboxylic acid titanium compound as a catalyst.

Abstract: There is provided a toner which is excellent in temporal stability and environmental stability of charges and which is capable of forming images that contains almost no background fog and has high density even in a long-term use and in use at a high-temperature and high-humid circumstance, and furthermore the toner which is not scattered inside an image forming apparatus and thus causes no contamination inside the apparatus, and there is further provided a method of manufacturing the above toner. An organic boron compound is contained as a charge control agent, a surface CCA concentration per specific surface area of toner falls in a range from 2.1×10?6 g/cm2 to 5.5×10?6 g/cm2, and a surface CCA concentration is 1.8×10?3 g/g or more.

Abstract: Toner particles are provided which may, in embodiments, include an additive package including a titanium dioxide that has been subjected to a fluorine treatment. In embodiments, additional additives, including a silica, optionally in combination with a metal salt of a fatty acid, for example a zinc stearate, may be included. The additives provide toners with excellent charging characteristics and good blocking performance.

Abstract: The present invention provides a toner for developing electrostatic image comprising a colored particle containing a binder resin, a colorant and a release agent, wherein the toner for developing electrostatic image has two or more peaks of loss tangent (tan ?) in the range from 50 to 120° C., a loss tangent (tan ?) in the range from 100 to 200° C. is 0.8 or less, and a dispersed diameter of the release agent is 0.1 times or less shorter than a volume average particle diameter of the colored particle.

Abstract: A ferrite carrier for an electrophotographic developer having a compression breaking strength of 150 MPa or more, a rate of compressive change of 15.0% or more and a shape factor SF-1 of 100 to 125, a method for producing the same, and an electrophotographic developer containing the ferrite carrier.

Abstract: A two-component developer containing a cyan toner and a magnetic carrier, wherein the cyan toner has the characteristics: (i) when the concentration of the cyan toner in a solution of the cyan toner in chloroform is represented by Cc (mg/ml) and the absorbance of the solution at a wavelength of 712 nm is represented by A712, a relationship between Cc and A712 satisfies the relationship of 2.00<A712/Cc<8.15; (ii) the lightness L* and chroma C* of the cyan toner determined in a powder state satisfy the relationships of 25.0?L*?40.0 and 50.0?C*?60.0; and (iii) the absolute value for the triboelectric charge quantity of the cyan toner measured by a two-component method using the cyan toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less.

Abstract: A toner for developing an electrostatic image comprises a binding resin for a toner and a charge control agent including an azo-type iron complex salt represented by the following chemical formula (1) (in the chemical formula (1), R1 and R3 are the same or different to each other and are an alkyl group having a straight chain or a branch chain of 3 to 8 carbons; R2a, R2b, R4a and R4b are the same or different to each other and are selected from the group consisting of a hydrogen atom, an alkyl group, an alkoxyl group, a halogen atom, a nitro group and a carboxyl group; A+ indicates m(H+)+n(K+)+p(Na+), which m, n and p satisfy numerical equations of m+n+p=1, 0.7?m?1, 0?n?0.3 and 0?p?0.3), wherein an average particle size thereof is 1 to 4 microns, and a specific volume resistivity thereof is ranging from 0.2×1015 to 7×1015 ?·cm.

Abstract: An objective is to provide a highly durable carrier for a developer which is capable of forming a high-definition image stably with no deterioration of a developing property since the carrier resistance and the charging ability remain stable even though the developer is used for a long duration; a method of manufacturing the carrier; and an image forming method employing the same. Disclosed is an electrophotographic carrier comprising a carrier core material and provided thereon, a resin-coated layer comprising charge control particles and low-resistive particles, wherein an initial carrier resistance is 5×108-3×1010 ?cm; a concentration of the low-resistive particles grows higher toward a surface of the layer from an inner part of the layer; and a concentration of the charge control particles grows lower toward a surface of the layer from an inner part of the layer.