Canon Kabushiki Kaisha

Yoshifumi Hano

Shuichi Aita

Tsutomu Kukimoto

Kiyoshi Mizoe

Fumihiro Arahira

Satoshi Yoshida

Toshiyuki Yoshihara

Motoo Urawa

Yuki Nishio

Kenji Okado

Tsuyoshi Takiguchi

Akio Maruyama

Ryoichi Fujita

Toshiyuki Ugai

Yuji Ishihara

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 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 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

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.

An image forming method includes forming an electrostatic latent image on an image bearing member having a surface of which contact angle with water is at least 90.degree., forming a toner layer on a toner carrying member, bringing the toner layer into contact with the surface of the image bearing member on which the electrostatic latent image has been formed, while rotating the image bearing member and the toner carrying member reciprocally, and developing the electrostatic latent image by the use of the toner of the toner layer to form a toner image.

Image forming method using a surface with a specified water contact

An electrophotographic image forming method including a toner image transfer step and eliminating an independent step for cleaning transfer residual toner is operated without causing ghost images and with good gradation and dot reproducibilities. In the method, the photosensitive member is exposed at an exposure intensity which is at least a minimum exposure intensity and below a maximum exposure intensity. The minimum exposure intensity is determined on a surface potential-exposure intensity characteristic curve of the photosensitive member by determining a first slope S1 of a straight line connecting a point giving a dark part potential Vd and a point giving a value of (Vd+ a residual potential Vr)/2, determining a contact point between a tangent line having a slope of S1/20 and the surface potential-exposure intensity characteristic curve and determining the minimum exposure intensity as an exposure intensity at the contact point. The maximum exposure intensity is determined as 5 times a half-attenuation exposure intensity.

Growing community of inventors

Inagi, Japan

Yoshifumi Hano