Canon Kabushiki Kaisha

Tetsuya Kuribayashi

Tsutomu Kukimoto

Hiroshi Yusa

Eiichi Imai

Koichi Tomiyama

Hisayuki Ochi

Hitoshi Uchide

Tsuyoshi Takiguchi

Manabu Ohno

Hiroyuki Suematsu

Tetsuhito Kuwashima

Naoto Kitamori

Takashi Tanaka

Satoshi Yasuda

Takeo Yamamoto

Fumihiro Arahira

Takao Honda

Shigemori Tanaka

Mitsuru Uchida

Hiroyuki Osada

Yuji Ishihara

Tsuyoshi Takuguchi

A charging device includes a movable member to be charged; a charging member contactable to the member to be charged to electrically charge the member to be charged; a discharging device, disposed upstream of a contact portion between the charging member and the member to be charged with respect to a movement direction of the member to be charged, for electrically discharging the member to be charged at a portion adjacent to the contact portion.

Charging member and image forming apparatus having contact charging

A developer carrying member comprises a substrate and a coating film. The surface of the substrate is covered with the coating film, and the coating film is formed with a film-forming composition. The film-forming composition contains graphite, a carbon black or a mixture thereof; a spherical material having a number average particle diameter of from 0.05 to 30.mu.; and a binder resin.

Developer carrying member, developing device unit

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

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.

A magnetic developer for developing an electrostatic latent image, including hydrophobic silica fine powder and an insulating magnetic toner comprising at least a binder resin and a magnetic material comprising spherical magnetic particles; wherein 0.16 to 1.6 wt. parts of the hydrophobic silica fine powder is mixed with 100 wt. parts of the insulating magnetic toner; the developer contains 17-60% by number of magnetic toner particles having a particle size of 5 microns or smaller, 5-50% by number of magnetic toner particles having a particle size of 6.35-10.08 microns, and 2.0% by volume or less of magnetic toner particles having a particle size of 12.7 microns or larger.

Magnetic developer, image forming method and image forming apparatus

A developer for developing electrostatic images, comprising: at least, 100 wt. parts of a negatively chargeable magnetic toner having a volume-average particle size of 5 to 30 microns; 0.1 to 3 wt. parts of positively chargeable resin particles having an average particle size of 0.1 to 1.0 micron; and 0.05 to 3 wt. parts of hydrophobic silica fine powder having a triboelectric chargeability of -100 to -300 .mu.c/g.

One component developer for developing electrostatic image and image

The present invention provides a contact charging member having a conductive layer free from resistance unevenness, comprising a conductive pigment and at least two kinds of polymeric elastic materials A and B, wherein the elastic material A has a higher affinity for the conductive pigment than the elastic material B.

Contact charging member, contact charging method making use of it, and

A magnetic developer for developing an electrostatic latent image, including hydrophobic silica fine powder and an insulating magnetic toner comprising at least a binder resin and a magnetic material comprising spherical magnetic particles; wherein 0.16 to 1.6 wt. parts of the hydrophobic silica fine powder is mixed with 100 wt. parts of the insulating magnetic toner; the developer contains 17-60% by number of magnetic toner particles having a particles size of 5 microns of smaller, 5-50% by number of magnetic toner particles having a particle size of 6.35-10.08 microns, and 2.0% by volume or less of magnetic toner particles having a particle size of 12.7 microns or larger.

Magnetic developer, comprising spherical particles magnetic

A developer for developing electrostatic images, comprising: at least, 100 wt. parts of a negatively chargeable magnetic toner having a volume-average particle size of 5 to 30 microns; 0.1 to 3 wt. parts of potitively chargeable resin particles having an average particle size of 0.1 to 1.0 micron; and 0.05 to 3 wt. parts of hydrophobic silica fine powder having a triboelectric chargeability of -100 to -300 .mu.c/g.

A magnetic toner suitably used for developing a digital latent image is provided. The magnetic toner comprises a binder resin and a specific magnetic material comprising spherical magnetic particles which have a tap density of 1.2-2.5 g/cm.sup.3 and a linseed oil absorption of 5-30 ml/100 g. On the basis of the characteristics of the above-mentioned magnetic material, the magnetic toner has good image forming characteristics including image density, reproducibility of thin lines and resolution.

Toner and image forming method using magnetic material with specific tap

A developer for developing electrostatic latent images comprises negatively chargeable toner particles and hydrophobic, negatively chargeable silica fine power,

Developer for developing electrostatic latent image and image forming

A toner for dry electrophotography comprises a binder resin, a metal complex compound (A) of an aromatic hydroxycarboxylic acid having a lipophilic group, and a metal complex salt-type monoazo dye (B) having a hydrophilic group. The compound (A) functions to enhances the negative triboelectric chargeability of the toner, and the dye (B) functions to leak an excessive charge of the toner, so that the toner is caused to have a uniform and sharp triboelectric charge distribution. As a result, the toner involves little liability of causing 'tailing', an irregularity caused by undesirable toner scattering.

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Tokyo, Japan

Tetsuya Kuribayashi