Patent classifications
G03G9/1135
Magnetic toner and method for manufacturing magnetic toner
Provided is a magnetic toner having a toner particle containing a binder resin and a magnetic body, wherein the binder resin contains a polymer A having a first monomer unit and a second monomer unit, the first polymerizable monomer is at least one selected from the group consisting of the (meth)acrylic acid esters having C.sub.18-36 alkyl groups, a content of the first monomer unit and a content of the second monomer unit based on the total moles of all monomer units in the polymer A are respectively 5.0 to 60.0 mol % and 20.0 to 95.0 mol %, and assuming that an SP value of the first monomer unit and the second monomer unit are taken as SP.sub.11 (J/cm.sup.3).sup.0.5 and SP.sub.21(J/cm.sup.3).sup.0.5, respectively, 3.00≤(SP.sub.21−SP.sub.11)≤25.00 is satisfied, and an oil absorption of the magnetic body is 5 to 40 ml/100 g.
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.
TWO-COMPONENT DEVELOPER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT
It is a two-component developer for electrostatic charge image development, which contains toner containing at least a binder resin and an external additive on a surface and a carrier containing a resin layer at least on a surface of a core material. The binder resin contains a crystalline polyester resin, the external additive contains alumina particles, and the resin layer contains a silicone resin.
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.
MAGNETIC TONER AND METHOD FOR MANUFACTURING MAGNETIC TONER
Provided is a magnetic toner having a toner particle containing a binder resin and a magnetic body, wherein the binder resin contains a polymer A having a first monomer unit and a second monomer unit, the first polymerizable monomer is at least one selected from the group consisting of the (meth)acrylic acid esters having C.sub.18-36 alkyl groups, a content of the first monomer unit and a content of the second monomer unit based on the total moles of all monomer units in the polymer A are respectively 5.0 to 60.0 mol % and 20.0 to 95.0 mol %, and assuming that an SP value of the first monomer unit and the second monomer unit are taken as SP.sub.11 (J/cm.sup.3).sup.0.5 and SP.sub.21(J/cm.sup.3).sup.0.5, respectively, 3.00(SP.sub.21SP.sub.11)25.00 is satisfied, and an oil absorption of the magnetic body is 5 to 40 ml/100 g.
ELECTROSTATIC IMAGE DEVELOPER, PROCESS CARTRIDGE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD
An electrostatic image developer includes: a toner A to which silica particles (A) containing an elemental nitrogen-containing compound containing elemental molybdenum are externally added; and a carrier B including a core material and a coating resin layer that covers the core material and contains inorganic particles. In the silica particles (A), the ratio N.sub.Mo/N.sub.Si of a Net intensity N.sub.Mo of elemental molybdenum that is measured by X-ray fluorescence analysis to a Net intensity N.sub.Si of elemental silicon that is measured by the X-ray fluorescence analysis is from 0.035 to 0.45 inclusive.
Carrier, developer, supplemental developer, image forming apparatus, image forming method, and process cartridge
A carrier is provided including a core particle and a resin layer coating the surface of the core particle. The resin layer includes fine metal particles, and a detected metal element amount A obtained by X-ray photoelectron spectrometry of the surface of the carrier is in a range of 4.0 atomic %A20.0 atomic % and an average major-axis length B of the fine metal particle exposing from the resin layer is in a range of 100 nmB800 nm.
TWO-COMPONENT DEVELOPER
In a two-component developer, toner particles include toner mother particles and external additive particles including strontium titanate particles. A first percentage content being a percentage content of the strontium titanate particles to the mass of the toner mother particles is 0.30-0.90% by mass. The carrier particles include carrier cores and coat layers. The coat layers contain barium titanate particles and a coating resin including a silicone resin. The barium titanate particles have a number average primary particle diameter of 100-500 nm. A second percentage content being a percentage content of the coat layers to the mass of the carrier cores is 2.0-4.0% by mass. A third percentage content being a percentage content of the barium titanate to the mass of the coating resin satisfies formula (1) (X?10)?Z?45.0. In formula (1), X represents the first percentage content and Z represents the third percentage content.
Image forming apparatus having two transfer units
An image forming apparatus includes: a first image forming unit that includes a first image holding member and a first developing unit, the first developing unit accommodating a first developer that includes a first toner and a first carrier; a first transfer unit; a second image forming unit that is disposed downstream of the first image forming unit in a traveling direction of a transfer medium and includes a second image holding member and a second developing unit, the second developing unit accommodating a second developer that includes a second toner and a second carrier; and a second transfer unit, in which a volume resistivity of the first carrier is higher than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is more than a volume average particle diameter of the second carrier.
IMAGE FORMING APPARATUS HAVING TWO TRANSFER UNITS
An image forming apparatus includes: a first image forming unit that includes a first image holding member and a first developing unit, the first developing unit accommodating a first developer that includes a first toner and a first carrier; a first transfer unit; a second image forming unit that is disposed downstream of the first image forming unit in a traveling direction of a transfer medium and includes a second image holding member and a second developing unit, the second developing unit accommodating a second developer that includes a second toner and a second carrier; and a second transfer unit, in which a volume resistivity of the first carrier is higher than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is more than a volume average particle diameter of the second carrier.