Ricoh Company, Ltd.

Kouji Sakamoto

Koichi Suzuki

Noriyuki Kimura

Takatsugu Fujishiro

Toshihiro Sugiyama

Eiichi Sasaki

Hiroyuki Matsushiro

Tsuyoshi Deki

Toshihiko Takaya

Kouichi Noguchi

Chiyako Kobayashi

Naomi Fukagawa

In an image forming apparatus, a developing device is disposed adjacent to a belt-like photosensitive member. A rotary type developing device has a hollow cylindrical casing rotatable around a shaft having a central portion for rotation. The developing device includes a casing which is rotated in a predetermined direction, and four partitions which divide the casing to make four developing units which extend radially outward from the shaft. A toner storing section or hopper is provided on one side of the developing device, i.e., on a front side of the image forming apparatus, and a toner cartridge is detachable from a top of the hopper, and the toner cartridge is exchanged when an end signal of the toner is detected by a sensor in the casing. The toner hopper is filled by new toner from the toner cartridge, and the toner is carried by conveyor members, which control an amount of the toner in the casing, and a supply roller supplies the toner to a developing roller. Therefore, the device supplies a required amount of toner to a toner supply roller and a developing roller at all times. This provides an image forming apparatus with a great freedom of layout which needs a minimum sectional space relative to a photoconductive element and which, therefore, has a miniature configuration. Also, if amounts of transport of first and second conveyor members are adequately selected, a uniform developer distribution in a longitudinal direction without resorting to a complicated control is insured.

Image forming apparatus having a revolver type developing device

A developing device of one-component developing type for use in the electrophotographic copying machine capable of developing latent image on the image carrier. The device comprises a developer carrying member having resistor layer on its surface layer, a regulation member for regulating the thickness of developer disposed on the developer carrying member, a replenishing member for replenishing developer onto the developer carrying member after finishing a process of developing, and a removing member for removing developer remaining on the developer carrying member after finishing a process of developing. The device sets the relationship of the time constants and the operational time periods in the form of inequalities, in order to obtain an optimum condition of developing. There are nine methods of setting the combination of time constant(s) and the operational time periods so as to satisfy the respective inequalities mentioned in the description of the invention.

Single component developing device with velocity of roller dependent on

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Tokyo, Japan

Kouji Sakamoto