Canon Kabushiki Kaisha

Kenji Okado

Ryoichi Fujita

Tsuyoshi Takiguchi

Kazumi Yoshizaki

Makoto Kanbayashi

Toshiyuki Ugai

Wakashi Iida

Yushi Mikuriya

Tetsuya Ida

Hiroyuki Kobayashi

Masaaki Taya

Yasuhiro Ichikawa

Shinya Yachi

Yasuo Mitsuhashi

Naotaka Ikeda

Mitsuru Uchida

Michihisa Magome

Tsutomu Kukimoto

Hatsuo Tajima

Masaki Uchiyama

Masanori Takenouchi

Tatsuya Nakamura

Akira Hashimoto

Masahiro Inoue

Akihiko Nakazawa

Yuji Sakemi

Keiji Komoto

Shuichi Aita

Motoo Urawa

Takayuki Nagatsuka

Yuji Moriki

Kazunori Murakawa

Hironori Minagawa

Yoshinobu Baba

Katsuhisa Yamazaki

Satoshi Yoshida

Masami Fujimoto

Takakuni Kobori

Daisuke Yoshiba

Tatsuhiko Chiba

Eiichi Imai

Masanori Shida

Kazunori Kato

Hiroaki Kawakami

Katsuyuki Nonaka

Yasushi Katsuta

Masashige Tamura

Keita Nozawa

Kenichi Nakayama

Kiyoshi Mizoe

Fumihiro Arahira

Junko Yoshikawa

Syuhei Moribe

Kohji Inaba

Yoshifumi Hano

Ryuichiro Maeyama

Yuki Karaki

Koshi Suematsu

Kouji Inaba

To provide a developer and an image forming method with each of which a high-resolution, high-definition image can be stably obtained over a long time period irrespective of an environment. The present invention provides a developer including at least: toner particles each containing at least a binder resin; and a composite inorganic fine powder, the developer being characterized in that: the composite inorganic fine powder has a peak at a Bragg angle (2&#x3b8;&#xb1;0.20 deg) of each of 32.20 deg, 25.80 deg, and 27.50 deg in a CuK&#x3b1; characteristic X-ray diffraction pattern; and the half width of the X-ray diffraction peak at a Bragg angle (2&#x3b8;&#xb1;0.20 deg) of 32.20 deg is 0.20 to 0.30 deg.

Developer and image forming method

A toner having a favorable fixability, excelling in charge stability, and capable of forming a image of retaining a high image density and a high resolution in long-term use is provided. That is, the toner of the present invention is a toner obtained by polymerizing a polymerizable monomer composition comprising a polymerizable monomer and a colorant, in which the polymerizable monomer composition is polymerized using a polymerization initiator comprising a redox initiator which includes an organic peroxide with a 10-hour half-life temperature of 86&#xb0; C. or higher and an reducing agent; the toner has a ratio of a weight-average particle diameter to a number-average particle diameter of 1.40 or less; and the toner has top of a main-peak in a molecular weight range of 5,000 to 50,000 in a molecular weight distribution measured using GPC of the THF-soluble part thereof, including t-butanol with a content of 0.1 to 1,000 ppm.

Toner

In an image forming apparatus having at least one single electrostatic latent image bearing member and a plurality of image forming units each having a replenishing developer cartridge and a developing assembly, at least one of the image forming units is a special-color image forming unit having a special-color replenishing developer cartridge containing a special-color replenishing developer, and at least one of the other image forming unit is a non-special-color image forming unit having a non-special-color replenishing developer cartridge containing a non-special-color replenishing developer. The special-color replenishing developer cartridge has a volume larger than the volume of the non-special-color replenishing developer cartridge, and the special-color replenishing developer contains a toner and a carrier.

Image forming apparatus, and replenishing developer kit

In an image forming apparatus having a powder transport mechanism including a powder container and a powder transport means which rotates relative to the powder container, the powder transport means has the rotation center substantially on the axis of the powder container, and the space between the inner wall surface of the powder container and the powder transport means is sealed with magnetic particles held by a magnetic-filed generation means. The magnetic particles have a specific saturation magnetization &#x3c3;s and a specific value of A&#xd7;&#x3c3;where the residual magnetic flux density of the magnetic-field generation means is represented by A in a specific range and the magnetization intencity of the magnetic particles in a magnetic field with the residual magnetic flux density A is represented by &#x3c3;.

Image forming apparatus

An electrostatic latent image on an image-bearing member is developed with a two-component developer comprising a toner and a carrier stored in a developer vessel while supplying as required a replenishing developer to the developer vessel. The replenishing developer comprises 1 wt. part of a carrier and 2-50 wt. parts of a toner, wherein the carrier is a magnetic fine particle-dispersed resin carrier comprising at least inorganic compound particles and a carrier binder resin, and the toner has a weight-average particle size of 3 to 10 &#x3bc;m and contains 1 to 40 wt. % of solid wax.

Replenishing developer and developing method

In a full-color image-forming method having at least a charging step, a latent-image-forming step, a developing step of developing an electrostatic latent image by the use of a developer; a transfer step, and a fixing step, the developer comprises a plurality of color developers and a black developer. The color developers are each a two-component developer for full-color image formation which has i) a color toner having color toner particles containing at least a binder resin, a colorant and a wax and ii) a carrier for the color developer. The black developer is a two-component developer for full-color image formation which has i) a black toner having black toner particles containing at least a binder resin, carbon black and a wax and ii) a carrier for the black developer. The carrier for the black developer has a larger absolute value of charge quantity when the same toner is used, than the respective carriers for the color developers.

Full-color image-forming method, and two-component developer kit for forming full-color images

A carrier for electrophotography and a two component type developer using the carrier. The carrier is composed of magnetic particles of a magnetic ferrite component represented by Formula: (Fe O ) (MnO) (A) . An image forming method is also disclosed which uses the two component type developer.

Carrier for electrophotography, two component type developer, and image forming method

Magnetic particles for charging means, and electrophotographic apparatus, process cartridge and image forming method including same

A magnetic toner includes: magnetic toner particles each comprising at least a binder resin and magnetic toner, and inorganic fine powder. The magnetic toner has an average circularity of at least 0.970, and a magnetization of 10-50 Am /kg at a magnetic field of 79.6 kA/m. The magnetic powder comprises at least magnetic iron oxide. The magnetic toner particles retain carbon in an amount of A and iron in an amount of B at surfaces thereof as measured by X-ray photoelectron spectroscopy, satisfying: B/A<0.001. The binder resin comprises a resin formed by polymerization of a monomer comprising at least styrene monomer. The magnetic toner has a residual styrene monomer content of less than 300 ppm, and contains at least 50% by number of toner particles satisfying a relationship of: D/C&lE;0.02, wherein C represents a volume-average particle size of the magnetic toner, and D represents a minimum distance between the surface of a magnetic toner particle and magnetic powder particles contained in the magnetic toner particle. Owing to the above features, the magnetic toner can exhibit good electrohotographic performances, including excellent chargeability and little transfer-residual toner, even in a cleanerless-mode image forming system.

Magnetic toner, process for production thereof, and image forming method, apparatus and process cartridge using the toner

Carrier for use in electrophotography, two-component type developer and image forming method

Toner and image forming method

A two-component type developer has a negatively chargeable toner having toner particles and an external additive and a magnetic-fine-particle-dispersed resin carrier. The magnetic-fine-particle-dispersed resin carrier has composite particles containing at least inorganic compound particles and a binder resin. The inorganic compound particles have been surface-treated with a lipophilic-treating agent having at least one type of functional group (A) selected from the group consisting of an epoxy group, an amino group, a mercapto group, an organic acid group, an ester group, a ketone group, an alkyl halide group and an aldehyde group, or a mixture of the agent. The composite particles have been surface-coated with at least one type of coupling agent having at least one type of functional group (B) different from the functional group (A) the lipophilic-treating agent. The functional group (B) the coupling agent has being a functional group or groups selected from the group consisting of an epoxy group, an amino group and a mercapto group. The negatively chargeable toner has a weight-average particle diameter of from 3 &mgr;m to 9 &mgr;m.

Two-component type developer and image forming method

An electrophotographic apparatus includes an electrophotographic photosensitive member, and (i) a charger, (ii) an imagewise exposure device, (iii) a developing device and (iv) a transfer device, disposed in this order opposite to the photosensitive member. The charger includes a charging member including magnetic particles disposed in contact with the photosensitive member so as to charge the photosensitive member based on a voltage received thereby. The magnetic particles are surface-coated with a coupling agent having a linear alkyl group having a least 6 carbon atoms. The developing device also functions to recover residual toner remaining on the photosensitive member processing by the transfer device and the charger. Because of the coating with such a specific coupling agent, the charging magnetic particles can exhibit good triboelectric changeability for the transfer residual toner for a long period.

Electrophotographic apparatus, image forming method, and process cartridge for developing an image with toner containing an external additive

In the image forming machine of the invention, a two-component type developer has a spherical magnetic powder dispersion type carrier, which has a weight average particle diameter of from 15 to 60 .mu.m. The external additive is present in the form of particles on the toner particle, and comprises inorganic oxide fine particles A having a shape factor SF-1 of from 100 to 130, and non-spherical inorganic oxide fine particles B, having a shape factor SF-1 larger than 150 and particles B having been obtained by combining a plurality of component particles.

Image forming method and image forming apparatus using specific

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Yokohama, Japan

Kenji Okado