Canon Kabushiki Kaisha

Osamu Tamura

Yoshihiro Ogawa

Koichi Tomiyama

Shunji Suzuki

Wataru Kitamura

Nobuyuki Okubo

Keita Nozawa

Takeshi Naka

Yoshihisa Saito

Takashige Kasuya

Tsutomu Kukimoto

Takakuni Kobori

Hiroshi Yusa

Kazunori Kato

Motoo Urawa

Masaichiro Katada

In a toner production process having at least a kneading step, a pulverization step and the step of simultaneously carrying out a surface modification step and a classification step to obtain toner particles, the surface modification and the classification are simultaneously carried out using a batch-wise surface modifying apparatus having at least a cylindrical main-body casing, a classifying rotor, a surface modifying means having a dispersing rotor and a liner. The positional relationship between the dispersing rotor and the liner is set in an appropriate specific state so that toner particles having a narrow particle size distribution with less fine powder and having a high sphericity can be obtained with a good efficiency.

Apparatus for modifying surfaces of toner particles

In a toner production process having at least a kneading step, a pulverization step and the step of simultaneously carrying out a surface modification step and a classification step to obtain toner particles, the surface modification and the classification are simultaneously carried out using a batch-wise surface modifying apparatus having at least a cylindrical main-body casing, a classifying rotor, a surface modifying means having a dispersing rotor and a liner. The positional relationship between the dispersing rotor and the liner is set in an appropriate specific state so that toner particles having a sharp particle size distribution with less fine powder and having a high sphericity can be obtained in a good efficiency.

Process for producing toner, and apparatus for modifying surfaces of toner particles

In a fixing method for fixing a toner image to a transfer medium, heat-and-pressure fixing is carried out using a specific pressure member and a specific toner. The pressure member has a heat-resistant elastic layer having a thermal conductivity of 0.20 W/m&middot;K or below. The toner has, in its DSC endothermic curve, at least a maximum value in the region of temperature of from 105&deg; C. to 150&deg; C., and, in GPC of THF-soluble component of the toner, a main peak in the region of molecular weight of from 2,000 to 25,000, a sub-peak or shoulder in the region of molecular weight of 70,000 or higher, and an Mw/Mn ratio of 8 or higher, containing 20% to 70% of a component belonging to the region of molecular weight of from 1,000 to 10,000.

Fixing method

A process cartridge is disclosed which includes an electrophotographic photosensitive member having a photosensitive layer and a charging means. The charging means has a charging member which is provided in contact with the electrophotographic photosensitive member to charge the photosensitive member electrostatically by applying a voltage formed by superimposing an alternating-current voltage on a direct-current voltage. The photosensitive member has a surface layer which contains at least one of a polyarylate resin having a weight-average molecular weight of 7.5&times;10 to 3.7&times;10 and having a specific structural unit of Formula (1) and a polycarbonate resin having a weight-average molecular weight of 7.5&times;10 to 3.7&times;10 and having a specific structural unit of Formula (2). The photosensitive member further contains fluorine-containing resin particles. Also, an electrophotographic apparatus having the photosensitive member is disclosed.

Process cartridge and electrophotographic apparatus

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

A toner is disclosed which contains toner particles and a hydrophobic fine silica powder. The hydrophobic fine silica powder has the following hydrophobic properties: the transmittance of the measuring sample fluid as defined in the specification at a methanol content of from 60% by volume to 72% by volume is 95% or more, and the transmittance of the measuring sample fluid at a methanol content of 74% by volume is 90% or more. Also, disclosed are an image forming method and an apparatus unit making use of the toner.

Toner, image forming method and apparatus unit

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

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

A toner for developing electrostatic images is constituted by toner particles comprising a binder resin and a colorant. The toner is characterized by having (i) a particle size distribution including a weight-average particle size D.sub.4 of X .mu.m and Y% by number of toner particles having a particle size of at most 3.17 .mu.m satisfying the following conditions (1) and (2):

Toner for developing electrostatic image, image forming method,

A developer for developing an electrostatic image has a toner which contains a particulate toner, a particulate silica A and a particulate silica B. The toner has a weight-average particle size of not larger than 12.0 .mu.m and a particle-number distribution showing not more than 50% of toner particles not larger than 4.0 .mu.m in particle size and not more than 10% of toner particles not smaller than 10.08 .mu.m in particle size, each of the toner particles having a toner composition containing at least a polymer component and a charge controlling agent. The particulate silica A is composed of silicone oil-treated silica particles and has an average particle size of not larger than 0.1 .mu.m, while the particulate silica B is composed of silicone oil-treated silica particles and has an average particle size of 0.5 to 50 .mu.m. The particulate silica B also has a particle-number distribution showing not more than 50% of silica particles not larger than 1.0 .mu.m in particle size and not more than 10% of silica particles not smaller than 100 .mu.m in particle size. Also disclosed is an image forming method which uses this developer.

Growing community of inventors

Kashiwa, Japan

Osamu Tamura