Patent classifications
G03G9/1131
Electrostatic-image developer and process cartridge
An electrostatic-image developer includes a toner and a resin-coated carrier. The toner includes toner particles including a binder resin, a release agent, and a non-ionic surfactant. The resin-coated carrier includes magnetic particles and a resin layer covering the magnetic particles. The resin-coated carrier has an absolute specific gravity of 3 g/cm.sup.3 or more and 4 g/cm.sup.3 or less.
ELECTROSTATIC-IMAGE DEVELOPER AND PROCESS CARTRIDGE
An electrostatic-image developer includes a toner and a resin-coated carrier. The toner includes toner particles including a binder resin, a release agent, and a non-ionic surfactant. The resin-coated carrier includes magnetic particles and a resin layer covering the magnetic particles. The resin-coated carrier has an absolute specific gravity of 3 g/cm.sup.3 or more and 4 g/cm.sup.3 or less.
Ferrite carrier core material for electrophotographic developer, ferrite carrier for electrophotographic developer, electrophotographic developer, and method for manufacturing ferrite carrier core material for electrophotographic developer
An object of the present invention is to provide a ferrite carrier core material for an electrophotographic developer having desired resistance properties and charging properties with small environmental variation of resistivity and charge amount while maintaining the advantages of ferrite carriers, a ferrite carrier for an electrophotographic developer, an electrophotographic developer using the ferrite carrier, and a method for manufacturing the ferrite carrier core material for an electrophotographic developer. In order to solve the problem, a ferrite carrier core material comprising ferrite particles containing 15 mass % or more and 25 mass % or less of Mn, 0.5 mass % or more and 5.0 mass % or less of Mg, 0.05 mass % or more and 4.0 mass % of Sr, and 45 mass % or more and 55 mass % or less of Fe, with Si localized in the surface thereof is used.
Magnetic core material for electrophotographic developer, carrier for electrophotographic developer, and developer
A magnetic core material for electrophotographic developer, satisfying a value of Expression (1): a+b10+c+d+e+f, being from 300 to 1,300, 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 BET specific surface area being from 0.06 to 0.25 m.sup.2/g.
Carrier core material and electrophotographic development carrier using same and electrophotographic developer
A carrier core material formed with ferrite particles, the skewness Rsk of the particle is equal to or more than 0.40 but equal to or less than 0.20, and the kurtosis Rku of the particle is equal to or more than 3.20 but equal to or less than 3.50. Here, the maximum height Rz of the particle is equal to or more than 2.20 m but equal to or less than 3.50 m. Moreover, the ferrite particle contains at least either of Mn and Mg elements. In this way, cracking or chipping in a concave-convex portion of a particle surface is unlikely to occur, and moreover, the amount of coating resin used can be reduced without properties such as electrical resistance being lowered.
Electrostatic image developer
Provided is an electrostatic charge image developer containing toner particles and carrier particles, wherein the toner particles contain at least silica particles or alumina particles as an external additive; the carrier particles contain core material particles and a coating resin layer covering a surface of the core particles; the coating resin layer contains metal oxide particles; an element measured by XPS (photoelectron spectroscopy) of the carrier particle is at least Si or Al; and a content of Si or Al in the carrier particle is in the range of 1 to 6 at % with respect to the total elements constituting the carrier particles.
CARRIER FOR DEVELOPING ELECTROSTATIC LATENT IMAGE, TWO-COMPONENT DEVELOPER, DEVELOPER FOR REPLENISHMENT, IMAGE FORMING DEVICE, PROCESS CARTRIDGE, AND IMAGE FORMING METHOD
A carrier for developing an electrostatic latent image includes a core material particle and a resin layer covering a surface of the core material particle. The resin layer includes a resin and at least one kind of a fine particle. At least one kind of the fine particles includes a chargeable fine particle. The chargeable fine particle has a long diameter of 400 to 900 nm. The chargeable fine particle has a shape factor SF-1 of 160 to 250.
MAGNETIC CARRIER AND TWO-COMPONENT DEVELOPER
A magnetic carrier comprising a magnetic carrier particle having a magnetic carrier particle having a magnetic carrier core particle and a resin coat layer formed on the magnetic carrier core particle surface, and inorganic fine particles A present on a surface of the magnetic carrier particle, wherein each of the inorganic fine particles A has a rectangular parallelepiped particle shape, the inorganic fine particles A have D1 of 10 to 60 nm, the inorganic fine particles A are inorganic particles which have been surface treated with a surface treatment agent or silane coupling agent-treated particles, SP1 of the resin coat layer and SP2 of the surface treatment agent satisfies SP1SP214.00, and the coverage ratio of the magnetic carrier surface by the inorganic fine particles A as measured by ESCA is 5.0 to 20.0 atom %: and a two-component developer comprising at least the magnetic carrier and a toner.
CARRIER, DEVELOPER, METHOD, AND APPARATUS FOR FORMING ELECTROPHOTOGRAPHIC IMAGE, AND PROCESS CARTRIDGE
A carrier for forming an electrophotographic image is provided. The carrier includes a core particle comprising a manganese-based ferrite particle having an apparent density of from 2.0 to 2.2 g/cm.sup.3 and a magnetization of from 44 to 52 emu/g in a magnetic field of 500 Oe; and a coating layer coating a surface of the core particle. The coating layer contains a carbon black, an inorganic particle A, and an inorganic particle B. The inorganic particle A and the carbon black each have a concentration gradient in a thickness direction of the coating layer. A concentration of the inorganic particle A increases toward a surface of the coating layer, and a concentration of the carbon black decreases toward the surface of the coating layer.
CARRIER AND TWO-COMPONENT DEVELOPER
A carrier includes carrier particles. The carrier particles include first carrier particles and second carrier particles. The first carrier particles each include a first carrier core and a first coat layer covering a surface of the first carrier core. The second carrier particles each include a second carrier core and a second coat layer covering a surface of the second carrier core. The first coat layers contain no fatty acid metal salt. The second coat layer contains a coat layer binder resin and a fatty acid metal salt. The second coat layers contain the fatty acid metal salt in a proportion of from 85 mass % to 95 mass % relative to a total mass of the second coat layers. The second carrier particles are contained in a proportion of from 7 mass % to 15 mass % relative to a total mass of the first carrier particles and the second carrier particles.