Patent classifications
G03G9/1139
ELECTROSTATIC IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD
An electrostatic image developer includes a toner including toner particles and an external additive, wherein an amount of the external additive that is loose relative to a total mass of the external additive is 5 mass % or less, and a carrier including magnetic particles and resin cover layers covering the magnetic particles and including inorganic particles, wherein a fine-irregularity-structure surface roughness of surfaces three-dimensionally analyzed has, in an analysis region, a ratio B/A of an irregularity-surface area B to a plan-view area A of 1.020 or more and 1.100 or less.
DEVELOPING DEVICE AND IMAGE FORMING APPARATUS INCLUDING THE SAME
A developing device includes a developing container storing a two-component developer containing a magnetic carrier and a toner, a developer carrying member carrying the developer on its outer circumferential surface, and a regulation member arranged to be opposed at a prescribed distance to the developer carrying member. The developer carrying member includes a developing sleeve on which a magnetic brush is formed, and a magnet secured in the developing sleeve and having a plurality of magnetic poles including a regulation pole opposed to the regulation member and a downstream-side magnetic pole arranged downstream of the regulation pole with respect to the rotation direction of the developing sleeve. The magnet is such that the vertical magnetic force gradient [mT/° ] has a local minimum value near a position at which the vertical magnetic force is 0 [mT] between the downstream-side surface of the regulation member and the downstream-side magnetic pole.
CARRIER, DEVELOPER, IMAGE FORMING METHOD, AND PROCESS CARTRIDGE
A carrier is provided that includes a core particle and a coating layer coating the core particle. The coating layer includes a resin and chargeable inorganic fine particles, and has voids. The resin has an average film thickness of 0.10 μm or larger and smaller than 0.45 μm. The coating layer has a porosity of 0.1% or higher and lower than 2.8%, when the porosity expressed by the following equation:
Porosity [%]=S1/S2×100
where, on a cross section of the coating layer, S1 represents a cross sectional area of the voids and S2 represents a cross sectional area of the resin.
ELECTROSTATIC LATENT IMAGE DEVELOPING WHITE DEVELOPER, IMAGE FORMING METHOD, IMAGE FORMING APPARATUS, AND PROCESS CARTRIDGE
Provided is an electrostatic latent image developing white toner, including: a white toner including at least a binder resin, a white pigment, and a release agent; and a magnetic carrier including at least a core material, and a coating layer coating the core material and made of a coating resin and conductive particles, wherein Ra of the magnetic carrier is in a range of from 0.50 μm to 1.00 μm, and a bulk density of the magnetic carrier is in a range of from 2.08 g/cm.sup.3 to 2.24 g/cm.sup.3.
CARRIER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT AND TWO-COMPONENT DEVELOPER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT
Provided is a carrier for electrostatic charge image development which provides a two-component developer having a high electric charge amount, a suppressed variation in an electric charge amount caused by an environmental change, and excellent durability, even if a low temperature fixable toner is used.
A carrier for electrostatic charge image development of the present invention includes: carrier particles in which a core particle surface is coated with a coating material containing a resin, wherein the coating material contains phosphorus element, and the resin contains structural units derived from an alicyclic (meth)acrylic acid ester compound.
Magnetic carrier
Provided is a magnetic carrier, including: a ferrite core particle; and a coating resin, in which: the coating resin has a surface resin layer and a resin composition in the stated order from a surface side thereof; the resin composition contains a resin, and an inorganic particle or carbon black that is subjected to a hydrophilic treatment; the surface resin layer contains a resin, is free of the inorganic particle or the carbon black, and has a thickness of from 0.01 μm or more to 4.00 μm or less; and a moisture percentage change between a moisture percentage when the magnetic carrier is left to stand under an environment of 30° C. and 80% RH for 24 hours, and a moisture percentage when the magnetic carrier is left to stand under an environment of 23° C. and 5% RH for 24 hours after the standing is 0.030 mass % or less.
DEVELOPING DEVICE AND IMAGE FORMING APPARATUS
A developing device, including: a developer containing toner and carrier; and developer bearer configured to have surface thereof bear the developer and endlessly move, and to develop latent image over surface of latent image bearer by supplying toner in developer to latent image in developing region facing the latent image bearer, wherein carrier contains fine particles, value X in volume resistivity R (=10.sup.X) (Ω.Math.cm) of carrier is 11.5-16.0, developer bearer includes: magnetic field generating unit including a plurality of magnetic poles; and developing sleeve having a cylindrical shape enclosing magnetic field generating unit, and configured to bear developer over outer circumferential surface of cylindrical shape by magnetic force of the magnetic field generating unit and perform surface moving by rotating relative to developing device body, and developing device includes developing sleeve voltage applying unit configured to apply AC component-containing voltage to developing sleeve.
ELECTROSTATIC CHARGE IMAGE DEVELOPING CARRIER, ELECTROSTATIC CHARGE IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD
An electrostatic charge image developing carrier includes a magnetic particle and a coating resin layer that covers the magnetic particle and contains an inorganic particle, and the following relation 1 is satisfied: 0<(C−A)/(B−A)≤0.40 (relation 1), in which A is a Net intensity of Si determined by an X-ray fluorescence analysis of a carrier A that is a carrier taken out from a developer A obtained by mixing a carrier and a toner with a silica particle externally added, B is a Net intensity of Si determined by the X-ray fluorescence analysis of a carrier B that is a carrier taken out from a developer B obtained by adding a silica particle to the developer A to obtain a mixture and stirring the mixture with a Turbula stirring apparatus for 20 minutes, and C is a Net intensity of Si determined by the X-ray fluorescence analysis of a carrier C that is a carrier taken out from a mixture C obtained by stirring a toner particle and the carrier B being the carrier taken out from the developer B for 2 minutes with the Turbula stirring apparatus.
ELECTROSTATIC CHARGE IMAGE DEVELOPING CARRIER, ELECTROSTATIC CHARGE IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD
An electrostatic charge image developing carrier includes a magnetic particle and a coating resin layer that covers the magnetic particle, and an amount of the coating resin layer that is peeled off from the magnetic particle when the carrier dispersed in water is irradiated with ultrasonic waves, relative to a coating amount of the coating resin layer before ultrasonic irradiation, is 800 mass ppm or more and 2,000 mass ppm or less, and a difference between an initial coating amount of the coating resin layer of a carrier having no travel history and a coating amount of the coating resin layer of a carrier having a travel history and being taken out from an electrostatic charge image developer, relative to the initial coating amount of the coating resin layer, is 0 mass ppm or more and 3,000 mass ppm or less.
ELECTROSTATIC CHARGE IMAGE DEVELOPING CARRIER, ELECTROSTATIC CHARGE IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS AND IMAGE FORMING METHOD
An electrostatic charge image developing carrier includes a magnetic particle and a coating resin layer that covers the magnetic particle and contains a silica particle, and a ratio of Si on a surface of the coating resin layer, determined by an X-ray photoelectron spectroscopy (XPS), is 6 atom % or more and 12 atom % or less.