G03G9/113

TWO-COMPONENT DEVELOPER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT, ELECTROPHOTOGRAPHIC IMAGE FORMING METHOD AND ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS
20220390873 · 2022-12-08 ·

Provided is a two-component developer for electrostatic charge image development including: toner particles containing toner base particles and an external additive disposed on a surface of the toner base particles; and carrier particles having a core material particle and a shell portion disposed on a surface of the core material particle, wherein the external additive contains inorganic particles surface-modified with a surface modifier represented by the following Formula (1); and a value of an iron element content (atomic %) measured by X-ray photoelectron spectroscopy (XPS) on a surface of the carrier particles satisfies the following Expression (1),


(R.sub.1).sub.4-n—Si—(X).sub.n  Formula (1):


4.0≤{A.sub.Fe/(A.sub.c+A.sub.o+A.sub.Fe)}×100≤15.0  Expression (1):

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 resin layer coating the core particle. The resin layer contains a chargeable particle A, a conductive particle B, a dispersing agent, and a defoaming agent.

ELECTROSTATIC CHARGE IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD

An electrostatic charge image developer contains: a toner containing a toner particle and an external additive; and a carrier containing a magnetic particle and a resin layer covering the magnetic particle; and the toner particle has a surface property index value of 1.0 or more and less than 2.0; and the carrier has a surface having a ratio B/A of a surface area B to a plane view area A of 1.020 or more and 1.100 or less, the plane view area A and the surface area B being obtained by three-dimensional analysis of the surface of the carrier.

ELECTROSTATIC CHARGE IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD

An electrostatic charge image developer containing: a toner containing a toner particle and an external additive; and a carrier containing a magnetic particle and a resin layer covering the magnetic particle, in which the toner particle has a surface property index value of 2.0 or more and 2.8 or less; and the carrier has a surface having a ratio BIA of a surface area B to a planar view area A of 1.020 or more and 1.100 or less, the planar view area A and the surface area B being obtained by three-dimensional analysis of the surface of the carrier.

ELECTROSTATIC IMAGE DEVELOPING CARRIER, ELECTROSTATIC IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD

An electrostatic image developing carrier includes core particles provided by dispersing a magnetic powder in a resin and resin cover layers covering the core particles, wherein the resin cover layers have a surface coverage of 96 area % or more, the resin cover layers include 10 mass % or more and 50 mass % or less of inorganic particles relative to a total mass of the resin cover layers, and the inorganic particles in surfaces of the carrier have a surface exposure ratio of 6 atomic % or more and 15 atomic % or less determined by X-ray photoelectron spectroscopy.

ELECTROSTATIC IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD

An electrostatic image developer includes a toner including toner particles that include a binder resin and a release agent and have an exposure ratio of the release agent of 15% or more and 30% or less, and a carrier including magnetic particles and resin cover layers covering the magnetic particles and including inorganic particles, wherein the inorganic particles have an arithmetic average particle size of 5 nm or more and 90 nm or less, the resin cover layers have an average thickness of 0.6 μm or more and 1.4 μm or less, and a fine-irregularity-structure surface roughness of surfaces of the carrier 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.

ELECTROSTATIC IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD

An electrostatic image developer includes a toner including toner particles that include a binder resin and a release agent and have an exposure ratio of the release agent of 15% or more and 30% or less, and a carrier including magnetic particles and resin cover layers covering the magnetic particles and including inorganic particles, wherein the inorganic particles have an arithmetic average particle size of 5 nm or more and 90 nm or less, the resin cover layers have an average thickness of 0.6 μm or more and 1.4 μm or less, and a fine-irregularity-structure surface roughness of surfaces of the carrier 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.

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.

FERRITE PARTICLES, ELECTROPHOTOGRAPHIC DEVELOPER CARRIER CORE MATERIAL, ELECTROPHOTOGRAPHIC DEVELOPER CARRIER, AND ELECTROPHOTOGRAPHIC DEVELOPER
20230152726 · 2023-05-18 · ·

The present invention relates to a ferrite particle containing a crystal phase component containing a perovskite crystal represented by a compositional formula: RZrO.sub.3 (provided that R represents an alkaline earth metal element), having a surface roughness Rz of 0.8 .Math.m or more and 3.5 .Math.m or less, and having a standard deviation Rzσ of the surface roughness Rz falling in a range represented by the following formula 0.15 × Rz ≤ Rzσ ≤ 0.60 × Rz. The ferrite particle can be used as an electrophotographic developer carrier core material. In addition, an electrophotographic developer carrier and an electrophotographic developer can be obtained.