Canon Kabushiki Kaisha

Koichi Tomiyama

Hiroshi Yusa

Tsutomu Kukimoto

Tsuyoshi Takiguchi

Eiichi Imai

Hiroyuki Suematsu

Shunji Suzuki

Hisayuki Ochi

Tetsuhito Kuwashima

Yoshihiro Ogawa

Takakuni Kobori

Manabu Ohno

Masayoshi Kato

Tetsuya Kuribayashi

Nobuyuki Okubo

Takashige Kasuya

Keita Nozawa

Tadashi Doujo

Osamu Tamura

Masaichiro Katada

Kiyoko Tsuchiya

Yushi Mikuriya

Satoshi Yasuda

Makoto Unno

Takaaki Kohtaki

Kazuo Yoshinaga

Tatsuhiko Chiba

Ryoichi Fujita

Satoshi Matsunaga

Hiroaki Kawakami

Shinya Yachi

Yoshihiko Hyosu

Seiichi Takagi

Ichiro Ohsaki

Nene Shibayama

Yuichi Mizoh

Minekazu Endo

Tsuyoshi Takuguchi

Toner for developing electrostatic image, image forming method and process cartridge

Magnetic toner for developing electrostatic images, process for producing it, image forming method and process cartridge

A yellow toner suitable for electrophotography is formed by dispersing a yellow colorant mixture in a binder resin. The yellow colorant mixture is formed of at least a pigment of formula (1) or (2) below, and a dye of formula (3) below:

Yellow toner, process for producing the tower and image forming method using the toner

A toner for developing electrostatic images includes a binder resin, a specific long-chain alkyl compound and a specific azo iron complex. The long-chain alkyl compound contains a terminal --OH or --COOH group and from about 35 to 150 (--CH.sub.2 --) groups. The azo iron complex has a cation including 75-98 mol. % of ammonium ion and another ion which is hydrogen, sodium, potassium or mixtures thereof.

Toner for developing electrostatic image, image forming method and

An electrophotographic toner including a blend of toner particles, and external additive particles, is provided with characteristic particle size distribution conditions, i.e., (i) a particle size distribution based on a Coulter counter measurement, including a weight-average particle size D4 of X .mu.m and Y % by number of particles having sizes of 2.00-3.17 .mu.m satisfying:

Toner for developing electrostatic images image forming method and

A toner is comprised of a composition containing at least a polymer component and a charge control agent. The polymer component contains substantially no tetrahydrofuran (THF)-insoluble matter. The polymer component THF-soluble has a major peak and a minor peak in the specific molecular weight regions in gel permeation chromatography (GPC). The low molecular weight component and high molecular weight component of the polymer component, each of which shows the specific molecular weight region in GPC, have the specific acid values, respectively. The difference between the acid values is in the specific range.

Process cartridge

An electrophotographic toner is composed of at least a binder resin, a colorant, and a wax. The binder resin (a) comprises a polyester resin, a vinyl resin and a hybrid resin component comprising a polyester unit and a vinyl polymer unit, (b) has a THF (tetrahydrofuran)-soluble content (W1) of 50-85 wt. % and a THF-insoluble content (W2) of 5-50 wt. %, an ethyl acetate-soluble content (W3) of 40-98 wt. % and an ethyl acetate-insoluble content (W4) of 2-60 wt. %, a chloroform-soluble content (W5) of 55-90 wt. % and a chloroform-insoluble content (W6) of 10-45 wt. %, respectively after 10 hours of Soxhlet extraction with respective solvents, giving a ratio W4/S6 of 1.1-4.0, and contains a THF-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight range of 4000-9000, including 35.0-65.0% (A1) of a component haing molecular weights in a range of 500 to below 1.times.10.sup.4, 25.0-45.0% (A2) of a component having molecular weights in a range of 1.times.10.sup.4 to below 1.times.10.sup.5 and 10.0-30.0% (A3) of a component having molecular weights of at least 1.times.10.sup.5 giving a ratio A1/A2 of 1.05-2.00. The binder resin shows good dispersibility of wax and colorant.

Toner and image forming method

Disclosed are a magnetic toner for developing an electrostatic latent image comprising magnetic toner particles containing a binder resin of 100 parts by weight and a magnetic substance of 20 to 150 parts by weight, and an apparatus unit and an image forming method for employing the magnetic toner. A frictional electrification property is such that the absolute value of the frictional electrification amount relative to an iron powder of 250 mesh-pass to 350 mesh-on is 25 to 40 mc/kg. Assuming that for particle distribution of the magnetic toner a weight-average particle diameter (D.sub.4) for the magnetic toner is X (.mu.m) and that a count % in a count distribution of magnetic toner particles that have a diameter of 3.17 .mu.m or smaller is Y (%), expressions (1) and (2) are satisfied:

Magnetic toner, apparatus unit and image forming method

An image forming apparatus includes a member to be charged for carrying an electrostatic latent image; a contact charging means for contact charging the member to be charged and a developing means for developing the latent image. The developing means includes a developer having a magnetic toner and fine powder treated with a silicone oil or varnish-treating agent, wherein the magnetic toner particles include a binder resin and contain from 10-70 wt. % of magnetic fine powder. An image forming method includes the steps of contact charging, latent image forming and developing with a developer having the binder resin, 10 to 70 wt. % magnetic fine powder and fine powder treated with a silicone oil or varnish-treating agent.

Images forming apparatus and developer for developing electrostatic

A magnetic toner for developing an electrostatic image has magnetic toner particles containing at least a binder resin and magnetic iron oxide particles. The magnetic iron oxide particles have been surface-treated with an aliphatic alcohol having carbon atoms of from 12 to 300 on the average. The magnetic toner has a weight average particle diameter of 13.5 .mu.m or smaller, and contains magnetic toner particles with particle diameters of 3.17 .mu.m or smaller in an amount not less than 1% by number as number-based percentage determined from number distribution.

Magnetic toner for developing electrostatic image, image forming

Toner for developing electrostatic images, process cartridge, and image

A magnetic toner is formed from a binder resin and silicon-containing magnetic iron oxide particles. The magnetic toner has a weight-average particle size of at most 13.5 .mu.m, and the magnetic toner has a particle size distribution such that magnetic toner particles having a particle size of at least 12.7 .mu.m are contained in an amount of at most 50 wt. %. The magnetic iron oxide particles have a silicon content of 0.4-2.0 wt. % based on iron, and the magnetic iron oxide particles have an Fe/Si atomic ratio of 1.2-4.0 at the utmost surfaces thereof. Because of the use of such magnetic iron oxide particles having a specifically controlled overall and surface Si contents, the magnetic toner can show stable performances even after standing in a high humidity environment.

Magnetic toner, process cartridge and image forming method

An image forming apparatus includes a member to be charged for carrying an electrostatic image, a contact-charging means for charging the member to be charged in contact with the member to be charged, and a developing means for developing the electrostatic image carried on the member to be charged. The developing means includes a developer for developing the electrostatic image comprising a toner and hydrophobic inorganic fine powder. The hydrophobic fine powder has a hydrophobicity of 60% or higher and the toner has a volume average particle size of 4-8 microns. The hydrophobic inorganic fine powder not only improves the fluidity of the developer and adjusts the chargeability of the developer but also prevents difficulties due to interaction between the member to be charged and the contact charging means in the presence of residual developer, such as damages of the member to be charged and toner-sticking onto the member to be charged.

Image forming apparatus and developer for developing electrostatic images

An image forming method, including the steps of: developing an electrostatic image formed on an electrostatic image-bearing member with a developer to form thereon thereon a developed image, the developer containing 100 wt. parts of a toner and 0.05 to 3 wt. parts of fine powder treated with a silicone oil or silicone varnish; and transferring the developed image on the electrostatic image-bearing member to a transfer material while causing a transfer device, such as a roller or belt to contact the electrostatic image-bearing member by the medium of the transfer material under a line pressure of 3 g/cm or higher.

Image forming method comprising electrostatic transfer of developed

A toner for developing electrostatic images is produced through a process including the steps of: pre-mixing binder resin particles carrying or containing inorganic fine powder to prepare a premix; melt-kneading the premix to obtain a kneaded product; cooling the kneaded product to obtain a colored resinous solid; pulverizing the colored resinous solid to obtain a pulverized product; and classifying the pulverized product to obtain toner particles. The inclusion of the resin particles carrying or containing inorganic fine powder improves the performance of the pre-mixing to provide an improved dispersion of toner materials within the product toner particles. A fine powder fraction from the classifying step can also be recycled to the premixing step. The resin particles can be toner particles per se. The inorganic fine powder may preferably be silica fine powder treated with silicone oil.

Production of toner for developing electrostatic images

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Kawasaki, Japan

Koichi Tomiyama