Abstract: A photosensitive layer included in an electrophotographic photosensitive member contains at least a charge generating material, a hole transport material, and a binder resin. The hole transport material includes a compound (1). The binder resin includes a polyarylate resin having at least one repeating unit (10) and at least one repeating unit (11). Alternatively, the binder resin includes a polycarbonate resin having a repeating unit (20) and a repeating unit (21).

Abstract: Toner comprising a toner particle containing binder resin and colorant, wherein fine particles A (organosilicon polymer particles containing an organosilicon polymer) and fine particles B are present at the toner particle surface, the organosilicon polymer has structure in which Si and O are alternately bonded to each other, portion of Si in the organosilicon polymer has R1—SiO3/2 structure, and content of the fine particles A, proportion for area of peak originating with silicon having the structure, volume resistivity of the fine particles B, total coverage ratio of the toner particle surface by the fine particles A embedded in the toner particle (A1) and the fine particles A not embedded in the toner particle (A2), percentage for area occupied by the fine particles A2, content of the fine particles B in the toner, and percentage for area occupied by the fine particles B embedded in the toner particle are prescribed range.

Abstract: A toner is provided. The toner comprises a binder resin, a colorant, and a release agent. The toner satisfies the following relations (1) and (2): 3.0×102?G?(50)/G?(80)??(1) T(107)?75 degrees C.??(2) where G?(50) represents a storage elastic modulus at 50 degrees C., G?(80) represents the storage elastic modulus at 80 degrees C., and T(107) represents a temperature at which the storage elastic modulus is 107 Pa or higher during a temperature fall from 100 degrees C. to 30 degrees C., in a measurement of dynamic viscoelasticity of the toner.

Abstract: A toner comprising an organosilicon polymer particle and a toner particle containing a binder resin and a wax, wherein the organosilicon polymer particle contains an organosilicon polymer, a part of silicon atoms in the organosilicon polymer has a T3 unit structure, a ratio of an area of peaks derived from silicon having the T3 unit structure relative to a total area of peaks derived from all silicon element contained in the organosilicon polymer particle is from 0.70 to 1.00 in 29Si-NMR measurement of the organosilicon polymer particle, a plurality of domains of the wax are present in a cross-section of the toner particle, the wax is an ester wax, the average long diameter of the domains of the ester wax is from 0.03 ?m to 2.00 ?m, and the SP value SPw of the wax is from 8.59 to 9.01.

Abstract: A toner comprising: a toner particle containing a binder resin; and an external additive, wherein the external additive comprises an external additive A and B; the external additive A has a number-average primary particle diameter of 35 to 300 nm, a dielectric constant ?ra of not more than 3.50, and a shape factor SF-1 of not more than 114, and is an organosilicon polymer particle having a particular T3 unit structure; a proportion for an area of a peak originating from silicon having the T3 unit structure with reference to that of all silicon elements is 0.50 to 1.00; the external additive B has a number-average primary particle diameter of from 5 nm to 25 nm and a dielectric constant ?rb that satisfies formula (A): 0.50??rb??ra (A); and a coverage ratio by the external additive B for the toner particle surface is 50% to 100%.

Abstract: Provided is a toner including a toner particle containing a binder resin, and an external additive, wherein the external additive contains an external additive A and an external additive B, the external additive A is an organosilicon polymer fine particle, the number-average particle diameter of primary particles of the organosilicon polymer fine particle is from 30 to 300 nm, the external additive B is a silica fine particle, the number-average particle diameter of primary particles of the silica fine particle is from 100 to 300 nm, the fixing rate of the external additive A to the toner particle according to a water washing method is less than 30%, and the fixing rate of the external additive B to the toner particle according to the washing method is at least 30%.

Abstract: A toner containing: a toner particle that contains a binder resin and an external additive, wherein the external additive contains an organosilicon polymer fine particle, the binder resin contains an amorphous resin and a crystalline polyester resin, a content of the crystalline polyester resin in the binder resin is from 5 to 30 mass %, and the crystalline polyester resin contains from 5 to 25 mass % of a component having a molecular weight of not more than 2,500.

Abstract: Provided is an electrophotographic photosensitive member including a surface layer containing: a copolymerization product of a composition containing a hole-transportable compound having a chain-polymerizable functional group and a compound having a specific structure; and metal oxide particles.

Abstract: Provided is a two-component developer has a toner including a toner particle including a binder resin, and a magnetic carrier, wherein the binder resin includes a polymer A having a first monomer unit derived from a first polymerizable monomer, and a second monomer unit derived from a second polymerizable monomer different from the first polymerizable monomer, the first polymerizable monomer is a specific (meth)acrylic acid ester, a content and an SP value of the first and second monomer units in the polymer A fall within respective specific ranges, the magnetic carrier has a magnetic core and a coating resin of the surface of the magnetic core, the coating resin includes a polymer B having monomer units (a) and (b), each SP value of the monomer units (a) and (b) is a specific value.

Abstract: A decolorizable toner allows for easy distinguishing between a sheet which can be reused and a sheet which is hardly able to be reused from each other. The decolorizable toner includes a color developable compound, a color developing agent, a decolorizing agent, a magnetic material, and a binder resin. The color developable compound is a precursor compound of a dye. The color developing agent is an electron accepting compound which donates a proton to the color developable compound. The decolorizing agent is a compound which inhibits a coloring reaction between the color developable compound and the color developing agent.

Abstract: A decolorizable toner allows for easy distinguishing between a sheet which can be reused and a sheet which is hardly able to be reused from each other. The decolorizable toner includes a color developable compound, a color developing agent, a decolorizing agent, a magnetic material, and a binder resin. The color developable compound is a precursor compound of a dye. The color developing agent is an electron accepting compound which donates a proton to the color developable compound. The decolorizing agent is a compound which inhibits a coloring reaction between the color developable compound and the color developing agent.

Abstract: A toner including a toner particle containing a binder resin and an external additive, wherein the toner particle contains a polyvalent metal compound, the polyvalent metal compound is at least one selected from the group consisting of aluminum compounds, iron compounds and magnesium compounds, a content of a metal element derived from the polyvalent metal compound in the toner particle is from 0.080 to 20.000 ?mol/g, the external additive contains an organosilicon polymer particle having a hydroxyl group, a ratio of a number-average particle diameter of the organosilicon polymer particle to a number-average particle diameter of the toner particle is from 0.0160 to 0.0650, and a content of the organosilicon polymer particle is at least 0.10 mass parts per 100.00 mass parts of the toner particle.

Abstract: A toner including a toner particle containing a polyester resin composition, wherein i) the polyester resin composition contains a specific aliphatic hydrocarbon and a polyester resin having at a terminal a structure derived from at least one of a specific alkyl monoalcohol and a specific alkyl monocarboxylic acid, and ii) the total content of the aliphatic hydrocarbon, the structure derived from the alkyl monoalcohol, and the structure derived from the alkyl monocarboxylic acid is 2.5 to 10.0% by mass, wherein, in the temperature-endothermic quantity curve of the polyester resin composition obtained by DSC, an endothermic peak is present in a specific temperature range and an endothermic quantity for this endothermic peak is 0.10 to 1.90 J/g.

Abstract: The present disclosure provides an electrophotographic photosensitive member that reduces the accumulation of charge and the leakage which are caused by a repeated use in a long period of time. The electrophotographic photosensitive member has a support, an undercoat layer, a charge generation layer and a charge transport layer in this order, wherein the undercoat layer contains a polyamide resin, and a titanium oxide particle, wherein the titanium oxide particle has been surfacetreated with an organosilicon compound, wherein the undercoat layer satisfies 10???70, where ? represents a degree [%] of hydrophobicity of the titanium oxide particle which has been surfacetreated with the organosilicon compound; and the undercoat layer satisfies 0.015?(?×?)?0.040, where ? represents an average primary particle size [?m] of the titanium oxide particles, and ? represents a weight percentage [wt %] of an Si element of the organosilicon compound with respect to the titanium oxide particle.

Abstract: Provided are toners and combinations of toners that demonstrate excellent color and are Ames test negative in both Salmonella typhimurium strains TA98 and TAIOO.

Abstract: Described herein is a metallic toner. The metallic toner includes flake shape toner particles having a binder resin, zinc stearate, silica having a particle size of from 7 nm to less than 12 nm in an amount of about 0.1 weight percent to 1.0 about weight percent of the flake shape toner particle and tabular shape metallic pigments. The flake shape toner particles have an average major axis length of from 6 ?m to 20 ?m, an average thickness of from 1 ?m to 4 ?m and an average circularity of from 0.5 to 0.97. The tabular shape metallic pigments have an average major axis length of from 1 ?m to 14 ?m an average thickness of from 0.01 ?m to 0.5 ?m.

Abstract: A toner including a toner particle that includes a binder resin and a crystalline polyester; and inorganic fine particles on the toner particle surface, wherein a content of the crystalline polyester is 0.5 to 20.0 mass parts per 100 mass parts of the binder resin; in the toner cross section, domains of the crystalline polyester are present in a dispersed state, the percentage for areas of these crystalline polyester domains in the region to a depth of 0.50 ?m from a contour of the toner particle is at least 10%, the number average of lengths of a major axis is 120 nm to 1000 nm, and the number average of aspect ratios is not more than 4; a dielectric constant of the inorganic fine particles is 25 to 300 pF/m; and a coverage ratio by the inorganic fine particles on the toner particle surface is 5% to 60%.

Abstract: An electrostatic charge image developing toner includes: toner particles including an amorphous resin and a crystalline polyester resin including a polycondensate of a linear dicarboxylic acid and a linear dialcohol having 2 to 12 carbon atoms; and an external additive including silica particles having a BET specific surface area of 100 m2/g or more. The electrostatic charge image developing toner satisfies the expression: 0.05??H2/?H1?0.95, wherein ?H1 (mW/g) is an endothermic energy amount based on an endothermic peak derived from the crystalline polyester resin in a first temperature increase process in differential scanning calorimetry according to ASTM D3418-8 (2008), and ?H2 (mW/g) is an endothermic energy amount based on an endothermic peak derived from the crystalline polyester resin in a second temperature increase process in differential scanning calorimetry according to ASTM D3418-8 (2008).

Abstract: Provided is an electrophotographic photosensitive member that can achieve both of abrasion resistance and the suppression of a ghost. The electrophotographic photosensitive member includes: a support; an undercoat layer; a charge-generating layer; and a charge-transporting layer, the undercoat layer, the charge-generating layer, and the charge-transporting layer being arranged in the stated order on the support, wherein the charge-transporting layer includes a charge-transporting substance, and a polymer containing a structure represented by the following general formula (1) and a structure represented by the following general formula (2), wherein the charge-generating layer includes a phthalocyanine crystal and a binder resin, and wherein the undercoat layer includes strontium titanate particles and a binder resin.

Abstract: A carrier core material is represented by a composition formula MXFe3-XO4 (where M is at least one type of metal element selected from Mg, Mn, Ca, Ti, Cu, Zn and Ni, 0<X<1), in which part of M and/or Fe is substituted with Sr and formed of ferrite particles, and in the carrier core material, a Sr content is equal to or more than 2500 ppm but equal to or less than 12000 ppm, the amount of Sr eluted with pure water at a temperature of 25° C. is equal to or less than 50 ppm, an apparent density is equal to or more than 1.85 g/cm3 but equal to or less than 2.25 g/cm3 and magnetization ?1k when a magnetic field of 79.58×103 A/m (1000 oersteds) is applied is equal to or more than 63 Am2/kg but equal to or less than 75 Am2/kg.