Kyocera Document Solutions Inc.

Kyocera Mita Corporation

Takeo Mizobe

Naruo Yabe

Hiroki Uemura

Yukinori Nakayama

Takanori Tanaka

Hiroaki Moriyama

Ryota Kobayashi

Takeshi Arakawa

Masanori Sugahara

Norio Kubo

Kouzou Teramoto

Kazuki Ono

A toner includes toner particles. The toner particles each include a toner mother particle containing a binder resin and an external additive attached to a surface of the toner mother particle. The external additive includes fluorine-containing particles. The fluorine-containing particles include a fluorine atom at least in surface layers thereof. The amount of the fluorine-containing particles is at least 0.10 parts by mass and no greater than 0.50 parts by mass relative to 100 parts by mass of the toner mother particles. When ultrasonication is performed, a residual amount ratio of remaining fluorine-containing particles is at least 0% by mass and no greater than 20% by mass relative to the amount of the fluorine-containing particles attached to the toner mother particles before the ultrasonication.

Toner, image forming apparatus, and image formation method

A toner includes toner particles. The toner particles each include a toner mother particle and an external additive attached to the surface of the toner mother particle. The external additive includes specific external additive particles. The specific external additive particles have a number average primary particle diameter of at least 30 nm and no greater than 305 nm. The specific external additive particles include antimony-doped tin oxide particles or indium tin oxide particles. A ratio (M/(M+M)) of a mass (M) of an antimony atom to a total of the mass (M) of the antimony atom and a mass (M) of a tin atom in the antimony-doped tin oxide particles is at least 0.04 and no greater than 0.46.

Toner

A toner contains toner particles. The toner particles each include a toner mother particle containing a binder resin and an external additive attached to a surface of the toner mother particle. The external additive contains titanate compound particles doped with lanthanum and a group 5 element in the periodic table as external additive particles. The amount of the lanthanum is at least 1.50% by mass relative to the total mass of the titanate compound particles. The amount of the group 5 element in the periodic table is at least 0.01% by mass and no greater than 0.60% by mass relative to the total mass of the titanate compound particles.

An electrostatic latent image developing toner of the present disclosure contains a toner particle including a toner core containing a binder resin, and a shell layer coating a surface of the toner core. The shell layer is constituted by a resin containing a thermosetting resin. A zeta potential of the toner core measured in an aqueous medium adjusted to pH 4 is negative, and a zeta potential of the toner particle measured in an aqueous medium adjusted to pH 4 is positive. A pH at which the zeta potential of the toner particle measured in an aqueous medium is zero is 4.5 or higher and 7.0 or lower.

Electrostatic latent image developing toner

A toner for electrostatic latent image development is comprised toner particles containing toner core particle containing at least a binder resin and a shell layer coating the toner core particle. The shell layer is smoothened to a predetermined level. The average particle diameter of the resin fine particles is from 45 nm to 300 nm. And, when cross-sections of the toner particles are observed using a transmission electron microscope, cracks approximately perpendicular to surfaces of the toner core particles are observable inside the shell layer.

Toner for electrostatic latent image development

A toner for electrostatic latent image development, containing toner particles composed of toner core particle containing at least a binder resin and a shell layer coating the toner core particle. Average circularities Dto Dof toner particles within predetermined particle diameter ranges are each no less than 0.960, the difference (D&#x2212;D) between a maximum value Damong Dto Dand a minimum value Damong Dto Dis no greater than 0.015. The shell layer is smoothened to a predetermined level. And, cracks in a direction approximately perpendicular to a surface of the toner core particles are observable inside the shell layer when cross-section of the toner particle is observed using a transmission electron microscope.

A magnetic toner for electrostatic latent image development includes toner particles containing toner core particle containing at least a binder resin and a magnetic powder, and a shell layer coating the toner core particle. In the toner, in the case where the surfaces of the shell layers are observed using a scanning electron microscope, the magnetic powder is not observed, and approximately spherical particles derived from the resin fine particles are not observed on the surfaces of the shell layers for toner particles having a particle diameter in a specific range. In the toner, in the case where the cross-sectional surfaces of the toner particles are observed using a transmission electron microscope, cracks approximately perpendicular to surfaces of the toner core particles are observed inside the shell layers.

Magnetic toner for electrostatic latent image development

A toner for electrostatic latent image development is comprised toner particles containing toner core particle containing at least a binder resin and a shell layer coating the toner core particle. The shell layer is smoothened to a predetermined level. And, when cross-sections of the toner particles are observed using a transmission electron microscope, cracks approximately perpendicular to surfaces of the toner core particles are observable inside the shell layer.

A toner set is composed of toners of a plurality of colors that are used in a tandem-type color image forming apparatus. Each of the toners of a plurality of colors includes toner base particles and an external additive. The external additive includes small-diameter silica particles and large-diameter silica particles larger than the small-diameter silica particles. When, of the toners of a plurality of colors, three color toners to be used consecutively for forming the toner image are defined as a first toner, second toner and third toner respectively in order of usage thereof, the average particle diameter of the large-diameter silica particles contained in the second toner is smaller than the average particle diameter of the large-diameter silica particles contained in the first toner and is larger than the average particle diameter of the large-diameter silica particles contained in the third toner.

Toner set, developer set, image forming apparatus, and image forming method

A two-component developing agent retained on the periphery surface of a magnetic rollerand a development rollerare brought in contact with each other, the nonmagnetic toner in the two-component developing agent is electrostatically adhered to the periphery surface of the development roller, and the nonmagnetic toner on the development rolleris sprayed on the periphery surface of a photosensitive drum, thereby causing an image of an electrostatic latent image to appear on the photosensitive drumas a toner image. The two-component developing agent for an image forming device thus configured comprises a nonmagnetic toner comprising color particles, and a magnetic carrier, wherein the magnetic carrier has a resin coating layer on the magnetic particle surface, and the critical surface tension of this resin coating layer is 25 dyn/cm or less.

Two component developing agent

The developing deviceincludes a stirrer and transferora magnetic rollerand a developing roller, that are disposed in a housingwhich contains the two-component developing agent including the magnetic carrier and the non-magnetic toner, wherein volumetric mean particle size of the non-magnetic toner is set in a range from 6 to 11 &#x3bc;m and proportion of toner particles not larger than 4 &#x3bc;m is set to 8% by number or less, thereby making it possible to prevent imaging defect (ghost) and sticking of the toner onto the developing roller from occurring.

Growing community of inventors

Osaka, Japan

Takeo Mizobe