Patent classifications
G03G9/0839
MANUFACTURING METHOD OF ELECTROSTATIC CHARGE IMAGE DEVELOPING CARRIER, AND MANUFACTURING METHOD OF ELECTROSTATIC CHARGE IMAGE DEVELOPER
A manufacturing method of an electrostatic charge image developing carrier, includes a step A in which a mixed solution containing a resin having a glass transition temperature Tg and a solvent is mixed with magnetic particles in a mixer, the mixture is heated to evaporate the solvent to form a resin coating layer on a surface of the magnetic particles so that resin-coated magnetic particles are obtained, and the resin-coated magnetic particles are crushed in a state of being maintained at a temperature T.sub.A; a step B in which the resin-coated magnetic particles after the step A are fluidized in a fluidized bed equipment in a state of being maintained at a temperature T.sub.B; and a step C in which the resin-coated magnetic particles after the step B are cooled, in which the temperature T.sub.A and the temperature T.sub.B are each independently equal to or higher than the glass transition temperature Tg20 C. and equal to or lower than the glass transition temperature Tg+50 C.
Magnetic one-component developer, developer cartridge, process cartridge, image forming apparatus, and image forming method
A magnetic one-component developer includes magnetic toner particles containing a binder resin and a magnetic powder, and silica particles having a compression and aggregation degree of 60% or more and 95% or less and a particle compression ratio of 0.20 or more and 0.40 or less.
TONER
Provided is a toner having a toner particle that contains a binder resin and a magnetic particle, wherein the magnetic particle satisfies the following stipulations (i) to (iii): (i) the magnetic particle has a prescribed shape and has a protruded portion on a plane portion thereof, (ii) the magnetic particle has a core particle that contains magnetite and has a coating layer, and (iii) the coating layer contains an iron-containing oxide and at least one of a silicon-containing oxide and an aluminum-containing oxide. In a molecular weight distribution measured on the tetrahydrofuran-soluble matter of the toner, the ratio (Mw/Mn) of a weight-average molecular weight to a number-average molecular weight is at least 10.0.
Magnetic toner
A magnetic toner includes toner particles. The toner particles contain a binder resin and a magnetic powder. The binder resin includes a crystalline polyester resin. The magnetic powder has a coating of a melamine resin. Preferably, the crystalline polyester resin has a solubility parameter (SP.sub.C) of no less than 9.5, and the solubility parameter (SP.sub.C) of the crystalline polyester resin and a solubility parameter (SP.sub.M) of the melamine resin satisfy formula (1) shown below.
SP.sub.CSP.sub.M>1.0(1)
TONER
Provided is a toner containing a toner particle including a binder resin, a wax, and a colorant. The softening point of the toner is at least 80 C. and not more than 140 C. The average circularity of the toner is at least 0.940. The integrated value of stress in the toner at 150 C. which is measured by using a tackiness tester is at least 78 g.Math.m/sec.
Magnetic toner
The magnetic toner includes magnetic toner particles comprising a binder resin and a magnetic body and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles comprise metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein; when a coverage ratio A (%) is a coverage ratio of the magnetic toner particle's surface by the inorganic fine particles and a coverage ratio B (%) is a coverage ratio of the magnetic toner particles' surface by the inorganic fine particles that are fixed to the magnetic toner particle's surface, the magnetic toner has a coverage ratio A, a coefficient of variation on the coverage ratio A, a ratio of the coverage ratio B to the coverage ratio A, and a compression ratio in a specific range.
Magnetic toner
A magnetic toner including: magnetic toner particles containing a binder resin, a magnetic body, and a release agent; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein the magnetic toner has a coverage ratio A of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B of the magnetic toner particles' surface by the inorganic fine particles fixed to the magnetic toner particles' surface that reside in prescribed numerical value ranges; the binder resin contains a styrene resin; the release agent contains a monoester compound or a diester compound; and the softening temperature and softening point of the magnetic toner reside in prescribed temperature ranges.
Toner having silica fine particles
A magnetic toner contains magnetic toner particles containing a binder resin, a release agent, and a magnetic body, and inorganic fine particles present on the surface of the magnetic toner particles, wherein a ratio of coverage of the magnetic toner particles' surface by the inorganic fine particles is in a prescribed range for the magnetic toner, the inorganic fine particles contain prescribed metal oxide fine particles, with at least 85 mass % of the metal oxide fine particles being silica fine particles, the coefficient of variation on the coverage ratio A is in a prescribed range, the binder resin contains a styrene resin, in a GPC measurement of a THF-soluble matter in the magnetic toner, a peak molecular weight (Mp) of a main peak is in a prescribed range, and a prescribed fatty acid ester compound is incorporated as a release agent.
Magnetic toner
Provided is a magnetic toner in which enhancement of initial transfer efficiency and transfer efficiency that is stable during a long-term use are achieved by simultaneously suppressing the friction force between the toner and a drum and the cohesion between toners, and further the degradation in chargeability and fluidity caused by the deterioration of the toner. The magnetic toner includes: a magnetic toner particle; a first external additive; and a second external additive. The first external additive includes an organic-inorganic composite fine particle, a plurality of convexes derived from an inorganic fine particle being present on a surface of the organic-inorganic composite fine particle, and has a number-average particle diameter of 50 nm or more and 500 nm or less. The second external additive includes a silica fine particle and has a number-average particle diameter of 5 nm or more and 30 nm or less. A shear load calculated from a rotation torque is 0.50 kPa or more and 2.00 kPa or less when a disc-shaped disc is pressed against a surface of a magnetic toner powder layer, the magnetic toner powder layer being produced by applying a vertical load of 9.0 kPa to the magnetic toner, under a vertical load of 5.0 kPa, and the disc which is being pressed is rotated, and an absolute value |(T)(A1)| of a difference between a zeta potential (T) of the magnetic toner particle dispersed in water and a zeta potential (A1) of the first external additive dispersed in water is 50 mV or less.
Toner
A magnetic toner is provided that exhibits an excellent dot reproducibility and developing performance after being allowed to stand in a high temperature and high humidity environment and an excellent low-temperature fixability. The magnetic toner has an inorganic fine powder and a magnetic toner particle containing a binder resin, a magnetic body, and a release agent, wherein in a stress relaxation measurement using a rotating plate rheometer, the magnetic toner exhibits a yield value A at 25 C. of at least 310.sup.6 (sec), and the magnetic toner that has been heated to 80 C. and then cooled to 25 C. exhibits a yield value B at 25 C. of not more than 110.sup.5 (sec).