Canon Kabushiki Kaisha

Tsuyoshi Takiguchi

Tsutomu Kukimoto

Kenji Okado

Hiroshi Yusa

Koichi Tomiyama

Eiichi Imai

Ryoichi Fujita

Wakashi Iida

Makoto Kanbayashi

Akira Hashimoto

Tetsuya Ida

Keiji Komoto

Manabu Ohno

Tetsuhito Kuwashima

Michihisa Magome

Tatsuhiko Chiba

Hiroyuki Suematsu

Toshiyuki Ugai

Hisayuki Ochi

Takashige Kasuya

Masanori Ito

Masaaki Taya

Yasuhiro Ichikawa

Tetsuya Kuribayashi

Katsuhisa Yamazaki

Satoshi Handa

Kaori Hiratsuka

Kimihiro Yoshimura

Yasukazu Ayaki

Yosuke Morikawa

Shuichi Aita

Takeshi Kaburagi

Kiyoshi Mizoe

Fumihiro Arahira

Satoshi Yoshida

Tatsuya Nakamura

Katsuhiko Tanaka

Kazunori Kato

Shinya Yachi

Takaaki Kohtaki

Kazuyoshi Hagiwara

Minoru Shimojo

Eriko Yanase

Kohji Inaba

Yoshifumi Hano

Yuki Karaki

Yuji Ishihara

Rika Doi

A toner exhibits excellent image characteristics, and also has an excellent charging property even if the toner is used in a cleaning-simultaneous-with-developing system having a direct injection charging mechanism. The toner includes toner particles and non-magnetic metallic-compound fine particles. The weight average particle diameter of the toner is 3.0 &#x3bc;m to 12.0 &#x3bc;m. The metallic-compound fine particles are conductive metallic-compound fine particles having a specific surface area (cm/cm) of 5&#xd7;10to 100&#xd7;10; a medium diameter (D) of 0.4 &#x3bc;m to 4.0 &#x3bc;m with respect to a volume-based particle diameter distribution, the medium diameter (D) being smaller than the weight average particle diameter of the toner; and a 90% particle diameter Dof 6.0 &#x3bc;m or less with respect to a volume-based particle diameter.

Toner, method for forming image using the toner, and process cartridge

A developer capable of providing an excellent image without causing a charging failure even after a long-term and repeated use contains a toner particle having a binder resin and a colorant, an inorganic fine particle, and a conductive fine particle, in which a volume average particle diameter Da of the conductive fine particle and an number average primary particle diameter Db of the inorganic fine particle satisfy the expression (1) below, and a rate of liberation 'a' of the conductive fine particle from the toner particle is 40 to 95% and a rate of liberation 'b' of the inorganic fine particle from the toner particle is 0.1 to 5%Da&#x2267;10Db. &#x2003;&#x2003;(1)

Developer

In an image forming system, an image-bearing member having a photoconductor layer comprising an Si-based non-single crystal material is charged at a relatively low potential of 250 to 600 volts by a contact charging member in the presence of electroconductive fine powder. An electrostatic latent image formed on the image-bearing member is developed with a magnetic toner which includes magnetic toner particles comprising at least a binder resin and a magnetic iron oxide, and inorganic fine powder and electroconductive fine powder present at the surface of the magnetic toner particles. The magnetic toner has a weight-average particle size of 3-10 &#x3bc;m and an average circularity of 0.950 to 0.995, and contains 0.05 to 3.00% of isolated iron-containing particles.

Image forming method and apparatus

A toner suitable for use in an image forming method including a contact charging step is provided. The toner includes: toner particles comprising at least a binder resin and a colorant, and fine particles. The fine particles comprise: (i) a tungsten-containing tin oxide, or (ii) base particles, and a tungsten-containing tin compound coating the base particles, the fine particles contain tin (Sn) in a weight ratio (Sn/b) of 0.01 to 2.0 with respect to the base particles (B). In the fine particles, tungsten (W) is contained in a mol ratio (W/Sn) of 0.001 to 0.3 with respect to the tin (Sn).

Toner and image forming method

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

A magnetic toner is formed of magnetic toner particles each comprising a binder resin, an iron oxide, a sulfur-containing polymer, and inorganic fine powder blended with the magnetic toner particles, the toner having a weight-average particle size (D4) of 3-10 &mgr;m, and either (a) an average circularity of at least 0.970, and a magnetization of 10-50 Am /kg (emu/g) at a magnetic field of 79.6 kA/m (1000 oersted), or (b) toner particles which retain carbon in an amount of A and iron in an amount of B at surfaces thereof, satisfying: B/A<0.001, and containing at least 50% by number of magnetic toner particles of D/C&lE;0.02, wherein C represents a particle projection area-equivalent circle diameter and D represents a minimum distance between a surface of the magnetic toner particle and iron oxide particles contained therein.

Magnetic toner

A toner is comprised of a binder resin, a colorant and a wax. The binder resin has a polycarbonate resin in an amount of from 0.1% by weight to 50.0% by weight and a resin other than the polycarbonate resin in an amount of from 50.0% by weight to 99.9% by weight, based on the weight of the binder resin. In molecular weight distribution as measured by gel permeation chromatography of tetrahydrofuran-soluble matter, the toner contains in an amount of 15.0% by weight or less based on the weight of the toner a component which has in its structure a repeating unit of the polycarbonate resin and is contained in components having a molecular weight of 1,000 or less.

A magnetic toner comprising magnetic toner particles containing at least a binder resin, a magnetic material containing a magnetic iron oxide, and a release agent. The magnetic toner has a weight-average particle diameter of from 3 &mgr;m to 10 &mgr;m, a magnetization intensity (saturation magnetization) of from 10 Am /kg to 50 Am /kg (emu/g) under application of a magnetic field of 79.6 kA/m (1,000 oersteds), an average circularity of 0.970 or more, a ratio of weight-average particle diameter to number-average particle diameter, of 1.40 or less, iron and an iron compound which stand liberated from the magnetic toner particles at a liberation percentage of from 0.05% to 3.00%, and a resin component having a tetrahydrofuran-insoluble matter in an amount of from 3% by weight to 60% by weight. Also disclosed is an image-forming method making use of the magnetic toner.

Magnetic toner and image-forming method making use of the same

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

A toner is formed of toner particles each comprising a binder resin and iron oxide particles dispersed therein. The toner particles are characterized by uniform but non-surface-exposed dispersion of the iron oxide particles within the toner particles as represented by (i) a carbon content (A) and an iron content (B) giving a ratio B/A<0.001 at surfaces of the toner particles as measured by X-ray photoelectron spectroscopy, (ii) an average circularity of at least 0.970, and (iii) at least 50% by number of toner particles satisfying D/C&lE;0.02, wherein C denotes a projection area-equivalent circular diameter of each toner particle and D denotes a minimum distance of iron oxide particles from a surface of the toner particle, based on a sectional view of the toner particle as observed through a transmission electron microscope (TEM).

A toner for developing an electrostatic image has toner particles containing at least a binder resin, a colorant, and a wax. The wax contains an ester compound represented by specific formula, or a mixture thereof at a content ranging from 50 to 100% by weight based on the weight of the wax.

Electrostatic image-developing toner and image-forming method

Growing community of inventors

Shizuoka-ken, Japan

Tsuyoshi Takiguchi