Abstract: The present invention relates to a toner binder containing: a polyester resin (A); and a vinyl resin (B), wherein the polyester resin (A) has an acid value of 2 mg KOH/g or more, the vinyl resin (B) has a weight average molecular weight of 4,000 to 40,000, the vinyl resin (B) is a polymer essentially containing a monomer (m) whose homopolymer has an SP value of 11.5 to 16.5 as a constituent monomer, the weight percentage of the monomer (m) in monomers constituting the vinyl resin (B) is 1 wt % or more based on the total weight of the monomers constituting the vinyl resin (B), the polyester resin (A) and the vinyl resin (B) are present at a weight ratio (A)/(B) of 80/20 to 99.5/0.

Abstract: Provided is an image forming method, including: transferring and fixing a toner onto a recording medium, and forming an image including a plurality of layers, in which an attachment amount of the toner on the recording medium is greater than or equal to 8 g/m2 and less than or equal to 40 g/m2, a toner forming a layer in contact with a fixing member contains at least a first mold release agent containing ester wax and a second mold release agent containing microcrystalline wax, and a special color toner is contained in any layer of the plurality of layers.

Abstract: The present disclosure provides an electrophotographic photosensitive member that can simultaneously achieve the suppression of the occurrence of the black spot in a charged portion and the suppression of the deterioration in sensitivity of an exposed portion, even after stored in a high-temperature and high-humidity environment. An electrophotographic photosensitive member includes an electro-conductive support, an undercoat layer, a charge generation layer and a charge transport layer in this order, wherein an atomic concentration ratio R of the oxygen atom to the aluminum atom on the surface of the electro-conductive support, as measured by energy dispersive X-ray spectroscopy, satisfies the following Expression (1): 1.6?R??(1) and the undercoat layer includes a titanium oxide particle that is surface-treated with a particular silane compound.

Abstract: An electrostatic charge image development toner contains toner particles and layered-structure compound particles. The layered-structure compound particles have a crystallite diameter of 150 ? or more and 250 ? or less as calculated from a maximum peak width in a Cu K? X-ray diffraction chart and have a number-average particle diameter Dn of 0.3 ?m or more and 2.0 ?m or less. The ratio Dn/Dv of a number-average particle diameter Dn of the layered-structure compound particles to a volume-average particle diameter Dv of the toner particles is 0.03 or more and 0.7 or less.

Abstract: A toner for developing an electrostatic charge image contains toner particles, layered-compound particles, and inorganic particles. The percentage Fa of layered-compound particles free from the toner particles is 5% by volume or more and 20% by volume or less.

Abstract: An electrostatic-image developing toner includes toner particles, layered compound particles, and inorganic particles. The inorganic particles have an average circularity of 0.910 or more and 0.995 or less. A ratio Da/Db of a number-average particle size Da of the layered compound particles to a number-average particle size Db of the inorganic particles is 1.2 or more and 43 or less.

Abstract: A polymeric composition including a copolymer comprising a first monomer having a high carbon to oxygen ratio of from about 3 to about 8; a second monomer comprising two or more vinyl groups, wherein the second monomer is present in the copolymer in an amount of from greater than about 8 percent by weight to about 40 percent by weight, based on the weight of the copolymer; and optionally, a third monomer comprising an amine, wherein the third monomer is present in an amount of from about 0.1 percent by weight to about 1.5 percent by weight, based on the weight of the copolymer; and a surfactant, wherein the surfactant has a minimum surface tension at critical micelle concentration of less than about 30 mN/m. A toner including the copolymer as a toner surface additive. An emulsion aggregation toner process including the copolymer as a toner surface additive.

Abstract: Provided is an electrophotographic photosensitive member in which the generation of a positive ghost image is suppressed under a low-temperature and low-humidity environment, and the occurrence of cracking is suppressed under a high-temperature and high-humidity environment. Also provided are a process cartridge mounted with the electrophotographic photosensitive member, and an electrophotographic apparatus including the process cartridge. The electrophotographic photosensitive member of the present disclosure is characterized in that an undercoat layer contains aluminum oxide particles and titanium oxide particles at a specific mass ratio.

Abstract: A toner comprising: a toner particle; and an external additive, wherein the external additive includes spherical silica particles and hydrotalcite particles, a number average particle diameter Da of the spherical silica particles is from 10 nm to 40 nm, a circularity of the spherical silica particles is at least 0.80, and the toner satisfies formula (1) below: {Ga×(1?Ka/100)}/{Gb×(1?Kb/100)}?0.050??(1) wherein Ga: a content of the spherical silica particles with respect to 100 parts by mass of the toner particle; Gb: a content of the hydrotalcite particles with respect to 100 parts by mass of the toner particle; Ka: a fixing ratio (%) of the spherical silica particles on a surface of the toner particle; and Kb: a fixing ratio (%) of the hydrotalcite particles on the surface of the toner particle.

Abstract: A toner comprising: a toner particle that includes a binder resin, and an external additive, wherein the toner particle includes a polyester resin on the surface; the toner particle includes a polyvalent metal element; where an electrical resistivity of the polyvalent metal element at 20° C. is denoted by A ?·m, and an amount of the polyvalent metal element in the toner particle is denoted by B ?mol/g, a following relationship is satisfied: 0.025×108?(1/A)×B?4.500×108; the external additive includes silica particles; and the silica particles includes spherical silica particles having a number average particle diameter of from 20 nm to 40 nm.

Abstract: The present invention relates to a carrier core material for electrophotographic developer, having a ferrite composition and having a supernatant transmittance of 85.0% or more, a method for producing the carrier core material, a carrier for electrophotographic developer, containing the carrier core material, and a developer containing the carrier.

Abstract: A toner comprising: a toner particle that contains a release agent-containing toner base particle, and an organosilicon polymer on a toner base particle surface, and an external additive A, the organosilicon polymer has a T3 unit structure; the organosilicon polymer forms protruded portions on the toner base particle surface; the number-average value of the protrusion height H is from 30 nm to 300 nm; the ratio of the number-average primary particle diameter R of the external additive A to the number-average value of the protrusion height H is from 1.00 to 4.00; the number-average primary particle diameter R of the external additive A is from 30 nm to 1,200 nm; and, in an image obtained by observing the toner surface with SEM, the area percentage for the bright region area in the image with reference to the total area of the image is from 30.0% to 75.0%.

Abstract: An electrostatic charge image development toner that is negatively chargeable contains toner particles and layered-structure compound particles. The layered-structure compound particles have a volume-average particle diameter Da of 0.4 ?m or more and less than 3.0 ?m. The ratio Da/Db of the volume-average particle diameter Da of the layered-structure compound particles to the volume-average particle diameter Db of the toner particles is 0.044 or more and 0.625 or less.

Abstract: Provided is an image forming method using an electrophotographic photoreceptor provided with a photosensitive layer and a protective layer in this order on a conductive support, and a toner, and the image forming method containing a charging step, an exposure step, a development step, a transfer step, a fixing step, and a cleaning step, wherein the protective layer contains at least a cured resin obtained by curing a polymerizable compound; the toner contains 50% by number or more of toner particles having a shape factor calculated by the equation (1) in the range of 1.2 to 1.6, and a variation coefficient of the shape factor is 16% or less; and the toner contains alumina particles having a number average particle diameter in the range of 5 to 60 nm and silica particles having a number average particle diameter in the range of 80 to 200 nm.

Abstract: To provide a magnetic core material and carrier for electrophotographic developer, which have small environmental dependence of the electric resistance, can suppress the carrier scattering, and can stably provide good images; a developer contains the carrier; and methods for producing them. The magnetic core material satisfying a value of Formula (1): a+b×10+c+d+e+f, being from 20 to 150, when a fluoride ion amount is denoted by a (ppm), a chloride ion amount is denoted by b (ppm), a bromide ion amount is denoted by c (ppm), a nitrite ion amount is denoted by d (ppm), a nitrate ion amount is denoted by e (ppm), and a sulfate ion amount is denoted by f (ppm), which are measured by a combustion ion chromatography method.

Abstract: A toner including a parent toner particle comprising at least one resin, in combination with an optional colorant, and an optional wax; and a surface additive formulation comprising at least one medium silica surface additive; at least one large silica surface additive; at least one positive charging surface additive, wherein the at least one positive charging surface additive is (a) a titanium dioxide surface additive; and wherein the parent toner particles further contain a small silica; or (b) a non-titanium dioxide positive charging metal oxide surface additive; and wherein the parent toner particles further optionally contain a small silica; and wherein a total surface area coverage of all of the surface additives combined is 100 to 140 percent of the parent toner particle surface area.

Abstract: A toner contains toner particles. The toner particles each include a toner mother particle containing a binder resin and an external additive attached to a surface of the toner mother particle. The external additive contains titanate compound particles doped with lanthanum and a group 5 element in the periodic table as external additive particles. The amount of the lanthanum is at least 1.50% by mass relative to the total mass of the titanate compound particles. The amount of the group 5 element in the periodic table is at least 0.01% by mass and no greater than 0.60% by mass relative to the total mass of the titanate compound particles.

Abstract: A toner including a parent toner particle comprising at least one resin, in combination with an optional colorant, and an optional wax; and a surface additive formulation comprising at least one medium silica surface additive; at least one large cross-linked organic polymeric additive; at least one positive charging surface additive, wherein the at least one positive charging surface additive is (a) a titanium dioxide surface additive; and wherein the parent toner particles further contain a small silica; or (b) a non-titanium dioxide positive charging metal oxide surface additive; and wherein the parent toner particles further optionally contain a small silica; and wherein a total surface area coverage of all of the surface additives combined is 100 to 140 percent of the parent toner particle surface area.

Abstract: A toner composition including a first wax; a second wax that is different from the first wax; wherein the first wax comprises a paraffin wax; wherein the second wax comprises a polymethylene wax; at least one polyester; and an optional colorant.

Abstract: An electrophotographic photoreceptor includes a support, an undercoat layer placed on the support, a charge generation layer placed on the undercoat layer, and a charge transport layer placed on the charge generation layer. The undercoat layer contains titanium oxide particles surface-treated with an organosilicon compound that is at least one member selected from the group consisting of compounds represented by formulas (1) to (8) and a polyamide resin. The charge generation layer contains hydroxygallium phthalocyanine.