Canon Kabushiki Kaisha

Michihisa Magome

Takashi Matsui

Yusuke Hasegawa

Shuichi Hiroko

Eriko Yanase

Tatsuhiko Chiba

Tomohisa Sano

Kozue Uratani

Atsuhiko Ohmori

Keiji Komoto

Tadashi Dojo

Yoshitaka Suzumura

Shotaro Nomura

Tatsuya Nakamura

Akira Hashimoto

Minoru Ito

Takeshi Kaburagi

Akira Sakakibara

Masaki Yamada

Tsuyoshi Takiguchi

Yuji Moriki

Hiroaki Kawakami

Kenji Okado

Tsutomu Kukimoto

Shinya Yachi

Keisuke Tanaka

Kazuhito Wakabayashi

Tomoya Uesugi

Wakashi Iida

Atsushi Tani

Masayoshi Shimamura

Atsuyoshi Abe

Masanori Ito

Ryoichi Fujita

Satoshi Otake

Kazumi Yoshizaki

Satoshi Handa

Kazunori Saiki

Koji Inaba

Kaori Hiratsuka

Kohji Inaba

Kiyokazu Suzuki

Nene Dojo

Yusutaka Akashi

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

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.

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.

Toner having silica fine particles

The developing apparatus includes a toner, a developing container, a developing roller, and a toner layer thickness controlling member,

Developing apparatus, developing method, image forming apparatus, and image forming method

A magnetic toner contains magnetic toner particles containing 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 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, when a coverage ratio A (%) is a coverage ratio of the magnetic toner particles' 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 particles' surface, the magnetic toner has a coverage ratio A and a coverage ratio B/coverage ratio A in prescribed ranges, wherein the magnetic toner has a dielectric constant &#x2208;' and a dielectric loss tangent in prescribed ranges.

A developing apparatus and a developing method that significantly suppress generation of fogging and form a high-quality electrophotographic images under any environments such as a high temperature and high humidity environment and a low temperature and low humidity environment are provided. A toner wherein a covering rate X1 of the surface of a toner particle with silica fine particles, which is determined by ESCA, is 40.0 to 75.0 area %, and the diffusion index represented by (Expression 1) diffusion index=X1/X2 satisfies (Expression 2) diffusion index&#x2267;&#x2212;0.0042&#xd7;X1+0.62 where in the theoretical covering rate with the silica fine particles is defined as X2; and a developing apparatus including a developing carrying member which is a surface layer formed of a urethane resin having a partial structure derived from a reaction of a polyisocyanate with a compound represented by Formula 1.

Provided is a developing apparatus, including toner for developing an electrostatic latent image, a toner carrier for carrying the toner, and a regulating member for regulating a layer thickness of the toner carried by the toner carrier. The toner carrier is placed to be brought into contact with the electrostatic latent image bearing member. The toner carrier includes a substrate, an elastic layer, and a surface layer containing a urethane resin. The urethane resin has a partial structure derived from a reaction between a compound represented by the structural formula (1) and a polyisocyanate. The toner contains toner particles each containing a binder resin and a magnetic material, and inorganic fine particles. The toner has a weight average particle diameter (D4) of from 9.5 &#x3bc;m to 14.0 &#x3bc;m. The toner has a porosity of 50 or more and 56 or less.

Image-forming apparatus, image-forming method, developing apparatus, and developing method

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 particle' 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.

A toner has toner particles including a binder resin, a colorant, an ester wax and a hydrocarbon wax; and inorganic fine particles. The ester wax includes an ester compound having a structure represented by formula (1): R&#x2014;CO&#x2014;O&#x2014;(CH)&#x2014;O&#x2014;OC&#x2014;R; or formula (2): R&#x2014;O&#x2014;OC&#x2014;(CH)&#x2014;CO&#x2014;O&#x2014;R. The ester wax includes an ester compound having a highest abundance rate in an amount of 40% to 80% by mass with respect to a total amount of the ester wax in a composition distribution. The ester wax has, in differential scanning calorimetry, a peak top temperature of an endothermic peak of 65&#xb0; C. to 80&#xb0; C. In differential scanning calorimetry, the toner has only one endothermic peak derived from the waxes. A relationship: 3.0&#x2266;(Tw&#x2212;Tt)&#x2266;8.0 is satisfied.

Toner

Provided is a developing apparatus, including: a toner for developing an electrostatic latent image; a toner carrier for carrying the toner; and a regulating member for regulating a layer thickness of the toner carried by the toner carrier, in which: the toner includes a toner containing toner particles each containing a binder resin and a magnetic material, and inorganic fine particles present on surfaces of the toner particles; the toner has a dielectric loss factor (&#x2208;&#x2033;) at a frequency of 100 kHz and a temperature of 30&#xb0; C. of 0.03 pF/m or more and 0.30 pF/m or less; the toner carrier includes a substrate, an elastic layer, and a surface layer containing a urethane resin; and the urethane resin has a partial structure derived from a reaction between a compound represented by the structural formula (1) and a polyisocyanate.

Developing apparatus, developing method, image-forming apparatus, and image-forming method

The present invention provides a developing apparatus including a toner, a toner carrying member and a regulating member, wherein the toner is a magnetic toner including a toner particle, a first fine silica particle having a number average primary particle diameter of 5 to 20 nm and a second fine silica particle having a number average primary particle diameter of 40 to 200 nm, the second fine silica particle is a fine silica particle produced by a sol-gel method, the toner has a total energy of 270 to 355 mJ/(g/ml), the toner carrying member has a substrate, an elastic layer and a surface layer including a urethane resin, and the urethane resin has a partial structure derived from a reaction of a particular amine type compound with a polyisocyanate.

Developing apparatus, developing method, image forming apparatus and image forming method

It is intended to provide magnetic toner that produces a stable image density in long-term use and can prevent ghosting under conditions of low-temperature and low-humidity. The present invention provides magnetic toner including magnetic toner particles each containing a binder resin, a magnetic material and a releasing agent, and silica fine particles, wherein the silica fine particles include silica fine particles A and B, the silica fine particles A have a number-average particle size of 5-20 nm as primary particles, the silica fine particles B are produced by a sol-gel method, and have a number-average particle size of 40-200 nm as primary particles, an abundance ratio of secondary particles of the silica fine particles B is 5-40% by number, and a coverage ratio X1 of the surface of the magnetic toner particles with the silica fine particles determined by ESCA is 40.0-75.0% by area.

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 the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, as described in the specification. The coverage ratio of the magnetic toner particles' surface by the inorganic fine particles and the coverage ratio by the inorganic fine particles fixed to the magnetic toner particles' surface reside in a prescribed relationship, the binder resin contains a polyester resin, the release agent contains an ester compound, and an endothermic peak for the magnetic toner has a prescribed value.

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Mishima, Japan

Michihisa Magome