Abstract: An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer containing a charge generating material, a hole transport material, a quinone derivative, and a binder resin. The quinone derivative is represented by general formula (1) or (2), where R1, R2, R3, R4, and R5 each represent, independently of one another, a hydrogen atom, an alkyl group having a carbon number of at least 1 and no greater than 12, an aryl group that has a carbon number of at least 6 and no greater than 14 and that may have an alkyl group having a carbon number of at least 1 and no greater than 6, an aralkyl group having a carbon number of at least 7 and no greater than 12, or a cycloalkyl group having a carbon number of at least 3 and no greater than 10. Z represents an oxygen atom or a sulfur atom.

Abstract: A developer having low-temperature fixability and storage stability, and capable of prolonging the service life is provided. A toner includes a coloring agent, an amorphous polyester, a crystal line polyester, ester wax containing multiple ester compounds, each having a carbon number selected from 32 to 54, and hydrophobic silica having an average primary particle diameter of 8 to 35 nm. When the ion intensity ratio of each ester compound having a different carbon number is expressed as percentage, the content (a) of the ester compound having a carbon number of (Cn) showing the maximum intensity ratio is from 20 to 55% by weight of the entire ester wax, the sum (g) of the content (e) of the ester compound having a carbon number of (Cn+2) and the content (f) of the ester compound having a carbon number of (Cn+4) satisfies the following formula: 0.065?g/a?0.200.

Abstract: An image forming apparatus includes: an electrophotographic photoreceptor that includes an electroconductive substrate, an undercoat layer which is provided on the electroconductive substrate and has electrostatic capacitance per unit area of from 2.5×10?11 F/cm2 to 2.5×10?10 F/cm2, and a photosensitive layer provided on the undercoat layer; a charging unit; an electrostatic latent image forming unit; a developing unit; an intermediate transfer member; a primary transfer unit that primarily transfers the toner image formed on the surface of the electrophotographic photoreceptor, onto the surface of an intermediate transfer member, while providing a primary transfer current value of from 80 ?A to 160 ?A; and a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member, onto a surface of a recording medium.

Abstract: Provided is an electrophotographic photoreceptor including a conductive support, a photosensitive layer, and a surface protective layer disposed in sequence. The surface protective layer includes a cured product of a composition containing a polymerizable compound, a charge transporting material, and at least two polymerization initiators. The polymerization initiators include an acyl phosphine oxide and an O-acyl oxime.

Abstract: An electrophotographic photosensitive member, in which occurrences of image defects are suppressed, and a method for manufacturing the electrophotographic photosensitive member are provided. In addition, a process cartridge and an electrophotographic apparatus, which include the electrophotographic photosensitive member, are provided. The surface layer of the electrophotographic photosensitive member contains a cured material, and the cured material is a copolymer of a hole transport compound having a chain-polymerizable functional group and a vinyl ester compound containing a long-chain alkyl group.

Abstract: A toner, containing: a binder resin; and kaolinite, wherein the toner has a molecular weight distribution having a main peak in a range of 1,000 to 10,000, and a half value width of the main peak is 8,000 to 30,000, where the molecular weight distribution is obtained by gel permeation chromatography (GPC) of THF soluble matter of the toner, and wherein the toner contains the kaolinite in an amount of 5% by mass to 35% by mass.

Abstract: Toner particles each have a toner core, a shell layer covering a surface of the toner core, and first resin particles containing a melamine resin. A shell layer coverage is 60% to 80%. The first resin particles each have an embedded portion and a protrusion portion. The embedded portions are embedded beneath the surface of the toner core. The protrusion portions protrude outward from the surface of the toner core in a radial direction of the toner particle. An average value Wd of thicknesses b of the shell layers, a number average value Dp of embedment depths c of the first resin particles, and a number average value Pd of primary particle diameters d of the first resin particles satisfy relations (1) to (3) shown below. 0.2?Dp/Pd?0.8??(1) (Pd?Dp)>Wd??(2) 0.10 ?m?Pd?1.

Abstract: In the electrophotographic photosensitive member of the present invention, a plurality of convex portions having a longest diameter L1 in the generatrix direction of the electrophotographic photosensitive member of 30 ?m or more arid a height H1 of 1 ?m or more are formed on the surface of the electrophotographic photosensitive member, a plurality of convex portions corresponding to the convex portions formed on the surface of the surface layer are formed at the interface between the surface layer and a layer immediately below the surface layer, and the rate of fitting of the convex portions formed on the surface of the surface layer to the convex portions formed at the interface between the surface layer and the layer immediately below the surface layer is 20% or more and 200% or less.

Abstract: An electrophotographic photoreceptor includes a conductive substrate satisfying a condition (A); an undercoat layer satisfying conditions (B) and (C), disposed on the conductive substrate, and containing metal oxide particles; and a photosensitive layer disposed on the undercoat layer: condition (A): in the case where depressions existing in the surface of the conductive substrate are observed with a laser microscope, the width of the largest depression is 400 ?m or less, and the depth of the depression is 15 ?m or less; condition (B): in the case where the undercoat layer is subjected to a Cole-Cole plot analysis, an angular frequency ?max at which a complex impedance component is maximum is from 2.0 rad to 25.0 rad; and condition (C): volume resistivity obtained from the Cole-Cole plot analysis of the undercoat layer is from 7.0×107? to 1.0×109?.

Abstract: A carrier includes a resin layer including Al and Sn and covering the surface of the carrier. A detectable amount of Al is from 1.0% to 12.1% by atom and a ratio (Al/Sn) of the detectable amount of Al to that of Sn is from 2.0 to 50.0 when the carrier is subjected to an X-ray photoelectron spectroscopic (XPS) analysis.

Abstract: A single-layer electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The conductive substrate contains aluminum or an aluminum alloy. A surface of the conductive substrate has an aluminum oxide film or an aluminum alloy oxide film. The photosensitive layer is disposed directly on the conductive substrate. The photosensitive layer contains an electron transport material. The electron transport material has a reduction potential of at least ?0.88 V and no greater than ?0.66 V versus a reference electrode (Ag/Ag+). The single-layer electrophotographic photosensitive member has a leakage onset voltage of at least 5.0 kV in a high temperature and humidity environment at a temperature of 30° C. and a relative humidity of 80%. The leakage onset voltage is a voltage applied to the single-layer electrophotographic photosensitive member at which current leakage starts.

Abstract: A magnetic carrier having a ferrite-type core material and a resin coat layer present on the surface of the ferrite-type core material, wherein the ferrite-type core material contains a magnetic ferrite-type core material particle and an amino group-bearing primer compound; the resin coat layer contains a coating resin A that is a polymer of monomer containing a (meth)acrylate ester having an alicyclic hydrocarbon group; the content of the amino group-bearing primer compound in the ferrite-type core material and the content of the resin coat layer in the magnetic carrier are within the prescribed range.

Abstract: An object of the present invention is to provide an electrostatic latent image developing toner containing: a binder resin; and a releasing agent, wherein the binder resin contains a crystalline polyester resin; an endothermic peak top temperature of the electrostatic latent image developing toner is 70° C. or more measured with differential scanning calorimetry (DSC) in a heating-up period of the toner; and a heat value ?Hc(L) is 15% or less with respect to a heat value ?Hc, wherein the heat value ?Hc(L) is a heat value in the range of (an exothermic peak top temperature rc?7° C.) or less; and the heat value ?Hc is a heat value of the total exothermic peak measured with DSC in a heating-down period of the toner.

Abstract: A method for coating pigment particles is provided, the method comprising heating a polymer resin in a carrier fluid to dissolve the polymer resin, suspending in the carrier fluid the pigment particles to be coated; and effecting precipitation of the polymer resin from the carrier fluid, such that a coating of the resin is formed on the pigment particles.

Abstract: An image forming apparatus includes an electrophotographic photoreceptor having an overcoat layer and a cleaning unit that includes a cleaning blade, a tip of which contacts with the electrophotographic photoreceptor, wherein the toner contains a toner particle which contains a binder resin containing a crystalline polyester resin, a colorant and a release agent, and an external additive, and the toner satisfies the following Expression: 2?tan ?P1?2.5, wherein tan ?P1 represents a maximum value of a mechanical loss tangent existing in a range where a complex elastic modulus is from 1×106 Pa to 1×108 Pa, which is measured at an angular frequency of 6.28 rad/sec and a strain amount of 0.3%.

Abstract: A method for coating pigment particles is provided, the method comprising heating a polymer resin in a carrier fluid to dissolve the polymer resin; suspending in the carrier fluid white pigment particles to be coated; and cooling the carrier fluid at a rate of 2° C./hr or less to effect precipitation of the polymer resin from the carrier fluid such that a coating of the resin is formed on the pigment particles, thereby producing the white liquid electrophotographic ink composition.

Abstract: Provided is a toner having a toner particle that contains a binder resin and a magnetic particle, wherein the magnetic particle satisfies the following stipulations (i) to (iii): (i) the magnetic particle has a prescribed shape and has a protruded portion on a plane portion thereof, (ii) the magnetic particle has a core particle that contains magnetite and has a coating layer, and (iii) the coating layer contains an iron-containing oxide and at least one of a silicon-containing oxide and an aluminum-containing oxide. In a molecular weight distribution measured on the tetrahydrofuran-soluble matter of the toner, the ratio (Mw/Mn) of a weight-average molecular weight to a number-average molecular weight is at least 10.0.

Abstract: An image forming apparatus includes an electrophotographic photoreceptor having an overcoat layer and a cleaning unit that includes a cleaning blade and a tip of the cleaning blade contacts with the photoreceptor toward the direction opposite to the rotation direction, wherein the toner particle contains a crystalline polyester resin, an average circularity of the toner particles is from 0.955 to 0.971, a content ratio of the toner particles having a particle diameter of 4.5 ?m or more and less than 7.5 ?m and a circularity of 0.980 or more is from 16% by number to 40% by number, and a content ratio of the toner particles having a particle diameter of 7.5 ?m or more and less than 15 ?m and a circularity of 0.900 or more and less than 0.940 is 3% by number or less.

Abstract: A toner including toner particles containing a binder resin, a pigment, a crystalline resin and an amorphous resin. The adsorption rate A1 of the crystalline resin to the pigment is from 5% to 40%, and the adsorption rate A2 of the amorphous resin to the pigment is from 20% to 60%. The adsorption rates A1 and A2 satisfy relationship (1): A1<A2.

Abstract: There is provided a toner set including a yellow toner, a cyan toner and a magenta toner, the toners each comprising an external additive and colored resin particles comprising a binder resin, a colorant and a charge control agent. An absolute value of an average of q/d for any of the yellow, cyan and magenta toners is expressed by charge amount q (fC) and particle diameter d (?m). It is obtained by measurement using an electric field detachment-type charge amount distribution measurement device. It is in a range of 2.0 to 6.5 fC/10 ?m, and a standard deviation (SD) of q/d is 13 fC/10 ?m or less. A difference between average values of q/d for any two of the yellow, cyan and magenta toners is 2.0 fC/10 ?m or less. A difference (?SD) between standard deviations of q/d for the two toners is 5.0 fC/10 ?m or less.