Patent classifications
G03G9/0837
White toner for developing electrostatic charge image, electrostatic charge image developer, and toner cartridge
A white toner for developing an electrostatic charge image includes a white toner particle containing a binder resin and a white pigment particle, wherein, when a number average circle equivalent diameter of the white pigment particles, which are observed in a sectional image of the white toner particle, is taken as A, and a number average circle equivalent diameter of the white pigment particles, which are present in a surface layer portion within 35% from a surface of the white toner particle with respect to a particle diameter thereof, is taken as B, a relationship expressed by A>B is satisfied.
TONER, ONE-COMPONENT DEVELOPER, AND TWO-COMPONENT DEVELOPER
A plurality of toner particles each include a toner core, a shell layer covering a surface of the toner core, and a plurality of magnetic particles penetrating the shell layer. Each of the magnetic particles has an embedded portion and a protrusion portion. The embedded portions are embedded in the surface of the toner core. The protrusion portions are located further outward than the embedded portions in a radial direction of the toner particle and protrude outward from a surface of the shell layer in the radial direction of the toner particle. An average Heywood diameter X of the magnetic particles, a shell layer thickness Y, and an average value Z of protrusion heights of the respective magnetic particles satisfy relation (1) and relation (2) shown below.
0<Z(X/2)(1)
10 nmY50 nm(2)
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.
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.
Toner using small-particle size magnetic iron oxide
Provided is a magnetic toner which exhibits a high degree of blackness and high tinting strength, and in which scraping of a toner carrying member surface by the magnetic toner is not caused, and image defects such as fogging and tailing are suppressed. A magnetic toner comprising a magnetic toner particle that contains a binder resin and a magnetic iron oxide particle, wherein, the number-average particle diameter of the magnetic iron oxide particle ranges from 0.05 m to 0.15 m, and a relationship between the number-average particle diameter (m) of the magnetic iron oxide particle and the specific surface area (m.sup.2/g) of the magnetic iron oxide particle satisfies Expression (1) below.
[Numberaverage particle diameter][specific surface area]1.10(1).
Toner and two-component developer
Provided are a toner and a two-component developer each of which: shows a small fluctuation in charge quantity and a small fluctuation in image density even under a high-temperature and high-humidity environment; and does not cause any member contamination even after endurance and hence can stably output an image. The toner and the two-component developer each have a feature in that positively chargeable strontium titanate fine particles are added to toner particles having fixed thereto negatively chargeable silica fine particles.
Toner
A toner is provided including large particle-diameter external additives with sweep to the concaves of a toner particle suppressed, so that the large particle-diameter external additives function as spacer particles for a long period. The toner includes toner particles which contain a binder resin and magnetic material, and organic-inorganic composite fine particles having a structure including inorganic fine particles embedded in a vinyl resin particle. The presence state of the magnetic material on the toner particle surface satisfies specific conditions and the presence state of the organic-inorganic composite fine particles on the toner surface satisfies specific conditions.
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).
Method for producing cobalt ferrite particles and cobalt ferrite particles produced by same
Provided are magnetic particles (cobalt ferrite) having a micrometer-order average particle diameter and similar particle diameters. A cobalt ferrite precursor is heated in the presence of a sulfite, thereby obtaining intended cobalt ferrite magnetic particles.