Canon Kabushiki Kaisha

Yuki Nishio

Shuichi Aita

Satoshi Yoshida

Tsutomu Kukimoto

Yoshifumi Hano

Tatsuya Nakamura

Toshiyuki Yoshihara

Masayoshi Kato

Motoo Urawa

Koji Inaba

Kengo Hayase

Image forming method

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

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

Kawasaki, Japan

Yuki Nishio