Canon Kabushiki Kaisha

Shuichi Aita

Yoshifumi Hano

Tsutomu Kukimoto

Kiyoshi Mizoe

Fumihiro Arahira

Satoshi Yoshida

Satoshi Yasuda

Toshiaki Nakahara

Yasuo Mitsuhashi

Motoo Urawa

Kiichiro Sakashita

Seiichi Takagi

Yoshinobu Nagai

Yuki Nishio

Kenji Okado

Tsuyoshi Takiguchi

Toshiyuki Yoshihara

Toshio Takamori

Tatsuya Nakamura

Akio Maruyama

Masayoshi Kato

Ryoichi Fujita

Kazunori Kato

Toshiyuki Ugai

Koji Inaba

Kengo Hayase

Eiji Funabashi

Yuji Ishihara

The present invention provides a one-component magnetic toner for developing an electrostatic charge image, which do not cause an image defect by toner aggregation or fusion even though a device is miniaturized and the processing speed of the device is accelerated, and which allows easy recycling of a toner cartridge. The one-component magnetic toner for developing an electrostatic charge image of the present invention is one comprising: toner particles comprising fine magnetic particles (A) and a binder resin; and fine magnetic particles (B) externally added to the toner particles, in which the maximum permeability (&#x3bc;m) of the fine magnetic particles (A) contained in the toner particles and the maximum permeability (&#x3bc;m) of the fine magnetic particles (B) externally added to the toner particles satisfy a relationship represented by the following formula (1)&#x3bc;m/&#x3bc;m.&#x2003;&#x2003;(1)

One-component magnetic toner for developing an electrostatic charge image, process cartridge, and method for recycling the process cartridge

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

Magnetic particles for charging an image-bearing member electrostatically. The charging magnetic particles have magnetic particles, first surface coat layers containing a first surface coating agent and covering the surfaces of the magnetic particles and second surface coat layers containing a second surface coating agent and covering the first surface coat layers. The charging magnetic particles contain magnetic particles for charging which have a maximum chord length of 5 &mgr;m or larger, and the magnetic particles for charging which have a maximum chord length of 5 &mgr;m or larger having a minor-axis length/major-axis length standard deviation of 0.08 or more. Also, a process for producing the charging magnetic particles is disclosed together with a charging member, a process cartridge and an image forming apparatus which make use of the charging magnetic particles.

Magnetic particles for charging, process for producing the magnetic particles, and charging member, process cartridge and image-forming apparatus which have the magnetic particles

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

A magnetic particle for charging is disclosed. The magnetic particle includes magnetic particles having particle diameters of 5 .mu.m or more. The magnetic particles having particle diameters of 5 .mu.m or more have a standard deviation of short-axis length/long-axis length of 0.08 or more, and a volume resistance value in the range of 10.sup.4 to 10.sup.9 .OMEGA.cm. Also, provided are a charging member, a charging device, a process cartridge and an electrophotographic apparatus, using the magnetic particle.

Magnetic particles for charging, charging member, charging device,

An electrophotographic apparatus includes: an electrophotographic photosensitive member, a charging device including a charging member formed of magnetic particles and disposed contactable to the photosensitive member so as to charge the photosensitive member based on a voltage applied thereto, exposure device, developing device, and a transfer device. The magnetic particles exhibit a good charging ability for a long period and therefore provide a good continuous image-forming performance because they are formed of ferrite particles including a ferrite having a very limited composition represented by the formula of:

Electrophotographic apparatus, image forming method and process cartridge

A charging apparatus which comprises an electrophotographic photosensitive member and a charging member which comprises magnetic particles and placed in contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member upon application of a voltage, wherein each magnetic particle has a surface layer containing a polyolefin resin of which weight average molecular weight is 10,000 or more, and has a volume resistivity of 1.times.10.sup.4 to 1.times.10.sup.11 .OMEGA.cm.

Charging apparatus and electrophotographic apparatus

An electrophotographic image forming method according to (I) a so-called simultaneous development and cleaning scheme or cleaner-less scheme is effectively operated by using a specific non-magnetic toner. (II) The non-magnetic toner comprises non-magnetic toner particles having a shape factor SF-1 of 120-160, a shape factor SF-2 of 115-140 and a weight-average particle size of 4-9 .mu.m. (III) The non-magnetic toner further includes inorganic fine particles (a) having a number-average primary particle size of at most 50 nm and spherical fine particles (b) having a number-average primary particle size of 50-1000 nm and a surface area-based sphericity .psi. of 0.91-1.00, respectively externally added to the non-magnetic toner particles.

Image forming method utilizing toner having inorganic particles and

An electrophotographic apparatus is constituted by an electrophotographic photosensitive member, and a charger, imagewise exposing light and a developer disposed in this order opposite to the photosensitive member. The photosensitive member has a surface layer which is a charge-injection layer. The charger includes a charging member formed of magnetic particles and disposed contactable to the photosensitive member so as to charge the photosensitive member to at least 80% of a DC voltage supplied to the charging member. The magnetic particles have a volume resistivity in the range of 1.times.10.sup.4 -1.times.10.sup.9 ohm.cm, and the magnetic particles have a surface layer having a volume resistivity of at most 1.times.10.sup.9 ohm.cm.

Electrophotographic apparatus using photoconductive member chargeable

A charging member, which electrically charges an object to be charged by being placed in contact with the object to be charged and by being applied with a voltage, is provided where the charging member includes an electroconductive base and brush bristles to come into contact with the object to be charged, and the brush bristles include at least one of etching fibers and divided fibers.

Charging member having bristless, process cartridge, and

A charging member includes a conductive substrate and a surface layer which is to be brought into contact with a member to be charged. On the surface layer a raised fiber entangled material is provided.

Charging member having a raised fiber-entangled material, and process

Image forming method

An image forming apparatus includes an image bearing member; developing-cleaning member for cleaning the image bearing member by removing residual toner from the image bearing member simultaneously with formation of a toner image by developing an electrostatic latent image formed on the image bearing member with toner having a charging polarity opposite from a charge polarity of the electrostatic latent image; transfer member for transferring the toner image from the image bearing member to a transfer material; and charging member for charging the toner remaining on the image bearing member after image transfer by the transfer member and before development by the developing-cleaning member to a polarity which is the same as the charging polarity of the toner image, and for charging the image bearing member to a polarity which is opposite from the charging polarity of the toner image.

Image forming apparatus

An image forming method and image forming apparatus for charging a photosensitive member, exposing the charged photosensitive member thereby forming an electrostatic latent image, carrying toner with a toner carrying member to bring the toner into contact with the photosensitive member surface, thereby developing the electrostatic latent image and forming a toner image upon the photosensitive member, transferring the toner image that is on the photosensitive member to transfer material such as paper, and conducting a simultaneous developing-cleaning process which recovers residual toner remaining on the photosensitive member following the transfer process, so that toner consumption is greatly reduced and high image quality is maintained at the same time. The angle of contact of the photosensitive member surface to water is 85.degree. or greater, the toner is comprised of at least toner particles possessing binder resin and coloring agent, and an inorganic fine powder, and the toner has an average particle diameter by volume DV (.mu.m) of 3 .mu.m.ltoreq.DV.ltoreq.8 .mu.m, an average particle diameter by weight D4 (.mu.m) of 3.5 .mu.m.ltoreq.D4.ltoreq.9 .mu.m, and the ratio Nr of particles having a particle diameter smaller than 5 .mu.m in particle diameter distribution by number of 17% by number.ltoreq.Nr.ltoreq.90% by number.

Image forming method and image forming apparatus

A charging apparatus or an electrophotographic apparatus includes an electrophotographic photosensitive member including a photosensitive layer provided on a conductive supporting member, and a charging member including magnetic particles, disposed to be in contact with the electrophotographic photosensitive member, for charging the electrophotographic photosensitive member when a voltage is applied to the charging member. The layer of the electrophotographic photosensitive member most separated from the conductive supporting member has a volume resistivity between 10.sup.8 .OMEGA..cm and 10.sup.15 .OMEGA..cm, and the magnetic particles have a hygroscopic property such that the ratio H/L of the maximum value H to the minimum value L of the amount of water contained within the particles is at least 1 and less than 4.

Growing community of inventors

Yokohama, Japan

Shuichi Aita