Ricoh Company, Ltd.

Hitachi Koki Co., Ltd.

Koutarou Yamada

Hiroshi Ueno

Katsuhiro Akinaga

Katuhiro Shinohara

Tomonari Hokkyoh

Kouhei Katayama

Hiroaki Maeda

Takashi Suzuki

Youji Hirose

Isao Watanabe

Yoshio Ogura

Minoru Murase

Hisashi Nakajima

A developing device in an image forming apparatus includes: a first developer carrier that rotates in a same direction as a rotating direction of an image carrier of the image forming apparatus so as to supply developer to the image carrier; and a second developer carrier that rotates in a direction opposite to the rotating direction of the image carrier so as to supply the developer to the image carrier. The developing device simultaneously performs a refreshing operation of performing replacement of the developer and a filming removal operation of causing the image carrier to rotate idle while forming an image for use in the refreshing operation and causing the first and second developer carriers to rotate in their respective rotating directions.

Image forming apparatus and image forming method

The disclosed image forming apparatus includes a rotatable image holding body configured to hold an electrostatic latent image on a surface of the image holding body, a developing device including a forward rotation developing roller rotatable in a same rotational direction as that of the rotatable image holding body and a reverse rotation developing roller rotatable in a reverse rotational direction to that of the rotatable image holding body, which supply a two-component developer to the surface of the image holding body to form a toner image corresponding to the electrostatic latent image, and a control unit configured to control rotation of the image holding body, the forward rotation developing roller, and the reverse rotation developing roller to supply the two-component developer. The control unit controls the rotation of the image holding body to start after a predetermined time period from starting the rotation of the forward rotation developing roller and the reverse rotation developing roller.

Image forming apparatus including counter-rotating developing rollers and controlling method

By providing a printing density controller for changing a printing density in a range from a dropout color to non-dropout color, an electrophotographic printing apparatus can conduct the light and shade adjustment of the printing density in a broad range, and also cope with the dropout color printing.

Electrophotographic apparatus having a printing density controller for dropout and non-dropout color

When a developing agent prepared to have a preset toner density is loaded in a developing unit, a comparing reference level for controlling the toner density in the developing agent is changed to a value higher than the preset value in the initial stage of operation and fresh toner is supplied to the developing agent so that the toner density of the developing agent is increased in comparison to the reference level. Thereby, the developed density is prevented from decreasing due to an excess amount of friction charge of the toner.

Developing unit for electro-photographic apparatus

Growing community of inventors

Ibaraki, Japan

Koutarou Yamada