Hitachi Koki Co., Ltd.

Kouhei Katayama

Hiroshi Ueno

Koutarou Yamada

Katuhiro Shinohara

Youji Hirose

Isao Watanabe

Yoshio Ogura

Hisashi Nakajima

Minoru Murase

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

Kouhei Katayama