Patent classifications
G03G9/1075
Ferrite particles, carrier for electrophotographic development using same, and developer for electrophotography
Ferrite particles have, as a main component, a material represented by a composition formula M.sub.xFe.sub.3−xO.sub.4 (where M is at least one type of metal selected from a group made of Mg, Mn, Ca, Ti, Cu, Zn, Sr and Ni, 0<x<1), where the maximum height Rz of the particles falls within a range of 1.40 μm to 1.90 μm, and the degree of distortion Rsk of the particles falls within a range of −0.25 to −0.07. In this way, when the ferrite particles are used as the carrier of an electrophotographic image forming apparatus, even if an image formation speed is increased, the occurrence of a failure is reduced for a long period of time.
Electrostatic charge image developing carrier, electrostatic charge image developer, developer cartridge, process cartridge, and image forming apparatus
An electrostatic charge image developing carrier includes a magnetic core particle, and a coating layer that coats surfaces of the magnetic core particle, wherein the coating layer includes a binder resin, thermosetting resin particles, and crosslinked resin particles, and the crosslinked resin particle contains a polymer formed by polymerizing a monomer component including the same monomer as a monomer used in the polymerization of the binder resin.
ELECTROSTATIC CHARGE IMAGE DEVELOPER, DEVELOPER CARTRIDGE, AND PROCESS CARTRIDGE
An electrostatic charge image developer includes an electrostatic charge image developing toner that includes toner particles, and an external additive which is added to the toner particles and which includes silica particles whose compression aggregation degree is from 60% to 95% and particle compression ratio is from 0.20 to 0.40, and a carrier for developing an electrostatic charge image that includes a core particle and a resin coated layer which covers a surface of the core particle and that has a surface roughness Ra (based on JIS-B0601) of 0.5 μm or less and a circularity of 0.975 or more.
MAGNETIC CARRIER, TWO-COMPONENT DEVELOPER, REPLENISHING DEVELOPER, AND IMAGE-FORMING METHOD
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.
METHOD FOR PRODUCING CARRIER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT, METHOD FOR PRODUCING ELECTROSTATIC CHARGE IMAGE DEVELOPER, IMAGE FORMING METHOD, AND CARRIER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT
A method for producing a carrier for electrostatic charge image development includes coating magnetic particles by adding the magnetic particles and a coating liquid containing a resin and a solvent to a mixer with a stirring blade to form a resin coating layer on surfaces of the magnetic particles and taking a carrier having the resin coating layer out of the mixer. In the coating, the stirring conditions after the solvent is evaporated and dried by heating in the mixer until the carrier is taken out of the mixer satisfy Formula 1 below and Formula 2 below:
0.2≤peripheral speed πDn (m/s) of stirring blade≤2.0 Formula 1,
1×10.sup.3≤stirring workload (peripheral speed×stirring time T)≤4×10.sup.3 Formula 2, where D represents a diameter (m) of the stirring blade, n represents a number of revolutions (rps) of the stirring blade, and T represents a time (s) from a time point at which, after a load power of the stirring blade before drying of the solvent increases with drying until completion of drying, a load power of the stirring blade decreases to 1.3 times or less the load power of the stirring blade before drying to a time point at which stirring in the mixer is stopped.
Electrostatic charge image developer, developer cartridge, and process cartridge
An electrostatic charge image developer includes an electrostatic charge image developing toner that includes toner particles, and an external additive which is added to the toner particles and which includes silica particles whose compression aggregation degree is from 60% to 95% and particle compression ratio is from 0.20 to 0.40, and a carrier for developing an electrostatic charge image that has a core including a magnetic member in a binder resin for a core and a coating layer which coders a surface or the core and which includes a resin for a coating layer and has a surface roughness Ra of from 0.25 μm to 0.4 μm.
TONER AND METHOD FOR MANUFACTURING TONER
A toner is provided, which is obtained by heat treating a toner particle containing a crystalline polyester resin, an amorphous polyester resin, a hydrocarbon wax and a wax dispersant, wherein the crystalline polyester resin is a hybrid resin having crystalline polyester segments and amorphous vinyl segments, and a mass ratio of crystalline polyester segments and amorphous vinyl segments in the crystalline polyester resin (crystalline segments/amorphous segments) is 70/30 to 98/2.
CARRIER FOR DEVELOPING ELECTROSTATIC LATENT IMAGES, TWO-COMPONENT DEVELOPER, IMAGE FORMING APPARATUS, TONER STORING UNIT, AND SUPPLEMENTAL DEVELOPER
A carrier for developing electrostatic latent images is provided. The carrier includes a magnetic core particle and a resin layer coating a surface of the magnetic core particle. The resin layer includes a particulate material A having a volume average particle diameter (a) and a particulate material B having a volume average particle diameter (b). The volume average particle diameter (a) of the particulate material A is the largest among volume average particle diameters of all particulate materials included in the resin layer, and an inequation 100≧(a)/(b)≧5 is satisfied. The particulate material A is barium sulfate.
Magnetic carrier and two-component developer
A magnetic carrier is provided which can suppress a decrease in glossiness even in a long term use for POD which requires high glossiness. A magnetic carrier includes a filled core particle in which a silicone resin is filled in pores of a porous magnetic core particle and a vinyl resin coating a surface of the filled core particle. In a pore distribution of the porous magnetic core particle measured by a mercury intrusion method, a cumulative pore volume in a pore diameter range of 0.1 to 3.0 μm is 35.0 to 95.0 mm.sup.3/g, and in a pore distribution of the filled core particle measured by a mercury intrusion method, a cumulative pore volume in a pore diameter range of 0.1 to 3.0 μm is 3.0 to 15.0 mm.sup.3/g. The magnetic carrier includes 1.2 to 3.0 parts by mass of the vinyl resin to 100.0 parts by mass of the filled core particle.
CARRIER FOR FORMING ELECTROPHOTOGRAPHIC IMAGE, DEVELOPER FOR FORMING ELECTROPHOTOGRAPHIC IMAGE, ELECTROPHOTOGRAPHIC IMAGE FORMING METHOD, ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS, AND PROCESS CARTRIDGE
A carrier for forming an electrophotographic image is provided. The carrier comprises a core particle and a coating layer coating the core particle. The coating layer contains chargeable particles and a dispersant. The carrier has an apparent density of from 2.0 g/cm.sup.3 or greater but less than 2.5 g/cm.sup.3.