Abstract: An image forming apparatus is provided that includes: an image bearer; a charger; an irradiator; a developing device containing a toner; and a transfer device. The image bearer has a Martens hardness of from 185 to 250 N/m2. The toner satisfies a relation 0.13?X/Dn?0.16, where X [?m] represents an average value of an amount of deformation of the toner by micro-indentation at when a load reaches 3.00×10?4 N at a loading rate of 3.0×10?5 N/sec under an environment of 32 degrees C. and 40% RH, and Dn [?m] represents a number average particle diameter of the toner. The toner contains an external additive comprising silica particles and particles composed mainly of strontium titanate. The particles composed mainly of strontium titanate further contain a third element M selected from the group consisting of La, Mg, Ca, Sn, and Si.

Abstract: A toner for electrostatic charge image development is a toner for electrostatic charge image development including toner particles containing a binder resin and an external additive, wherein the binder resin contains a crystalline polyester resin and an amorphous polyester resin, the external additive includes Al—Si composite oxide particles, and a Si element content of the Al—Si composite oxide particles is in the range of 50 to 90 mass % and a Si element ratio on surfaces of the Al—Si composite oxide particles is in the range of 3 to 35 at %.

Abstract: An electrostatic charge image developer contains toner particles, layered-compound particles that are particles of a nitrogen-containing layered compound, and a resin-coated carrier that has magnetic particles and a resin layer covering the magnetic particles. The maximum height Ry of the roughness profile as defined in JIS B0601: 1994 of the surface of the resin-coated carrier is 0.01 ?m or more and 0.20 ?m or less.

Abstract: An electrophotographic photoreceptor includes an electroconductive substrate; and a photosensitive layer that is formed on the electroconductive substrate and that contains an inorganic oxide and a lubricant resin which contains a polycarbonate resin having a siloxane structure therein or a polyarylate resin having a siloxane structure therein. When light having a wavelength of 780 nm is irradiated onto a slurry containing 20% by mass of the inorganic oxide in a predetermined solvent to provide an inorganic oxide slurry, the inorganic oxide slurry has a light transmittance that is 80% or more. The photosensitive layer may be a negatively-charged laminate-type photosensitive layer, a monolayer type photosensitive layer, or a positively-charged laminate-type photosensitive layer. The electrophotographic photoreceptor is less worn upon long-term use, allows no filming, and can realize stable images.

Abstract: An electrostatic image developing toner includes toner particles, layered compound particles, and inorganic particles. The proportion of irregular-shaped inorganic particles having a circularity of 0.5 or more and 0.9 or less and a size of 0.015 ?m or more and 0.350 ?m or less to the entire inorganic particles is 2% by number or more and 70% by number or less.

Abstract: Provided is a toner including a binder resin and a colorant, wherein the colorant includes Solvent Red 49, and an acid value of the toner is 9.0 mgKOH/g or greater but 30.0 mgKOH/g or less.

Abstract: A toner including: a plate-shaped pigment containing a metal as a main component; and a binder resin containing polyester resin (A) that is insoluble in THF, wherein: a weight average molecular weight (Mw) of a tetrahydrofuran (THF)-soluble component of the toner as determined by gel permeation chromatography (GPC) is 5,000 or higher but 14,000 or lower; and a glass transition temperature (Tg) of a THF-insoluble component of the toner as determined from a differential scanning colorimetry (DSC) curve at first heating in DSC is ?60° C. or higher but 10° C. or lower.

Abstract: A toner including toner particles, each toner particle including a toner base particle, and inorganic particles, wherein the inorganic particles include particles of a fluorine-containing aluminium compound, and a liberation ratio of the inorganic particles is 10% or greater but 60% or less.

Abstract: An electrostatic-image developing toner includes toner particles, aggregated silica particles A treated with an oil, and aggregated or non-aggregated silica particles B rendered hydrophobic with a hydrophobizing agent other than an oil. The average particle size Da of the aggregated silica particles A and the average particle size Db of the silica particles B satisfy Da?Db. The electrostatic-image developing toner does not include any external additive other than the aggregated silica particles A or the silica particles B, or the electrostatic-image developing toner includes an external additive other than the aggregated silica particles A or the silica particles B, the other external additive having an average particle size smaller than the average particle size Da.

Abstract: A toner set includes a color toner and a transparent toner that has a pressure phase transition property. The color toner and the transparent toner satisfy 1.0?tan ?1?4.0 and 1.2?tan ?1/tan ?2?3.0 where tan ?1 represents tan ? of the color toner at 100° C., and tan ?2 represents tan ? of the transparent toner at 100° C.

Abstract: An electrophotographic photoreceptor, including a photosensitive layer formed on an electroconductive substrate. The photosensitive layer includes a charge-generating material and an electron-transporting material, and the electron-transporting material includes first and second electron-transporting materials. A difference in lowest unoccupied molecular orbital (LUMO) energy between the first electron-transporting material and the charge-generating material is in a range from 1.0 to 1.5 eV, and a difference in LUMO energy between the second electron-transporting material and the charge-generating material is in a range from 0.6 to 0.9 eV. A ratio of mass of the second electron-transporting material to a total of mass of the first electron-transporting material and the mass of the second electron-transporting material is in a range from 3 to 40%.

Abstract: A toner is provided which includes: a toner base particle including a binder resin; and an external additive including inorganic particles. A particle size distribution of primary particles of the inorganic particles has a plurality of peaks in the range of from 5 nm through 50 nm. The particle size distribution of the primary particles satisfies all of expressions (1) to (3) below: n1d>n2d??(1); 10<(n1d+n2d)??(2); and 30?{(n2h/n1h)×100}<100??(3), where n1d is a particle diameter (nm) at a peak n1 which is the highest peak among the plurality of peaks and n2d is a particle diameter (nm) of a peak n2 which is the second highest peak among the plurality of peaks, and n1h is a height of the peak n1 and n2h is a height of the peak n2.

Abstract: Provided is a toner including a binder resin, a release agent, and a charge-controlling agent, wherein the toner includes toner particles having particle diameters of 3 micrometers or smaller, among the toner particles having particle diameters of 3 micrometers or smaller, a proportion of the toner particles having an average circularity of 0.70 or greater but 0.85 or less in all of the toner particles is 10% by number or greater but less than 20% by number and a proportion of the toner particles having an average circularity of less than 0.70 in all of the toner particles is 10% by number or less.

Abstract: A white toner comprising a toner particle including a binder resin, an inorganic white pigment, and a polyvalent metal salt compound, wherein the inorganic white pigment has an acidic group at a surface thereof; an amount of the inorganic white pigment in the toner particle is 10% to 50% by volume; the polyvalent metal salt compound is a specific compound; an absolute value of the difference between an SP value (J/cm3)1/2 of the binder resin and that of the polyvalent metal salt compound is 0.0 to 6.0; and an amount of the polyvalent metal salt compound, an amount of a polyvalent metal, the amount of the inorganic white pigment, and an amount of the acidic group at a surface of the inorganic white pigment satisfy a specific relationship.

Abstract: The present invention relates to a toner binder containing: a polyester resin (A); and a vinyl resin (B), wherein the polyester resin (A) is a resin obtained by crosslinking a polyester (A1) by one or more carbon-carbon bonds, the vinyl resin (B) is a polymer containing a monomer (a) as an essential constituent monomer, the monomer (a) is a C21-C40 (meth)acrylate having an acyclic hydrocarbon group, and the weight proportion of the monomer (a) in monomers constituting the vinyl resin (B) is 15 to 99% by weight based on the weight of the vinyl resin (B).

Abstract: An electrophotographic photoconductor is provided that includes a conductive substrate, an undercoat layer overlying the conductive substrate, and a photosensitive layer overlying the undercoat layer. The undercoat layer contains zinc oxide particles and a binder resin and has a volume resistivity of 0.03×106 ?·cm or less in an electrical field of 5 V/?m at a temperature of 23 degrees C. and a relative humidity of 55%. The photosensitive layer contains a compound represented by the following general formula (1): where each of R1 to R3 independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms.

Abstract: A toner including a toner particle containing a binder resin and an external additive, wherein the external additive contains composite particles of an organosilicon polymer fine particle and a fatty acid metal salt.

Abstract: A toner including: a toner particle that includes a binder resin and a crystalline material, wherein the binder resin includes a vinyl resin having an ether structure, and where intensities of secondary ion mass/secondary ion charge number (m/z) of 59, 44, and 135 are denoted by A (ppm), B (ppm), and C (ppm), respectively, in a measurement of the toner by time-of-flight secondary ion mass spectrometry, the intensities at 100 nm from the surface of the toner satisfy the relationships of the following formulas (1) and (2): C/(A+B)?1.00??(1) (A+B)?2000??(2).

Abstract: An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The hole transport material includes a compound represented by chemical formula (1-1) or (1-2). The photosensitive layer further contains an n-type pigment. The n-type pigment is preferably an azo pigment or a perylene pigment.

Abstract: A magnetic core material for electrophotographic developer, satisfying a value of Expression (1): a+b×10+c+d+e+f, being from 200 to 1,400, when an amount of fluorine ion is denoted by a (ppm), an amount of chlorine ion is denoted by b (ppm), an amount of bromide ion is denoted by c (ppm), an amount of nitrite ion is denoted by d (ppm), an amount of nitrate ion is denoted by e (ppm), and an amount of sulfate ion is denoted by f (ppm), which are measured by combustion ion chromatography; and having a pore volume of from 30 to 100 mm3/g.