Ricoh Company, Ltd.

Toshihiko Takaya

Toshihiro Sugiyama

Toshio Kaneko

Yoshihiro Ogata

Hiroyuki Matsushiro

Fuchio Takeda

Shuichi Endoh

Michihito Ohashi

Akito Yoshimaru

Kinzi Saito

Shuichi Endo

Atsushi Shinozaki

Kouji Sakamoto

Toyoji Ishikawa

Naomi Fukagawa

Shinzi Nagatsuna

A developing unit incorporated in an image forming apparatus and having a waste toner container for collecting a waste toner and a fresh toner container containing a fresh toner and adjoining the waste toner container. When the waste toner container is filled with the waste toner, the developing unit causes the waste toner to enter the fresh toner container while preventing the fresh toner from entering the waste toner container. A wall separates the waste toner and fresh toner containers from each other and is formed with an opening. A shutter is associated with the opening and opens when the pressure inside the waste toner container increases due to the waste toner. The waste toner which enters the fresh toner container via the opening is agitated together with the fresh toner as far as possible and then fed to a developing roller or is collected in a container whose volume is variable.

Developing unit for an image forming apparatus having adjoining fresh

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

An apparatus having a plurality of replaceable parts. Replaceable parts to which the same life is assigned beforehand are replaced at the same time by hand or by use of a jig. Lives which are integral multiples of the shortest life which one of the replaceable parts has each is assigned to respective one of the other replaceable parts. Hence, when the life of a certain part has expired, the part having the shortest life is automatically replaced together with the part whose life has expired. The replaceable parts each is mounted on and locked to the apparatus and, when the life thereof has expired, unlocked from the apparatus. The expiration of the life is detected either electrically or mechanically, and the parts reached the end of the life is indicated. Before the life of a replaceable part expires, a spare part for replacing it is prepared by detecting that the life is about to expire. The deterioration of a part having a comparatively long life is measured to correct the time for replacing it.

Apparatus having a plurality of replaceable parts

An image developing device for use in an electrophotographic copying apparatus or a printer includes a developing roller for supplying toner to a latent image formed on a latent image carrier to develop the latent image into a visible toner image. The image developing device also includes a toner supply roller independently rotatable in abutting engagement with the developing roller for supplying the toner onto the developing roller. Each of the toner supply roller and the developing roller is electrically conductive. An electric potential with its polarity dependent on whether the toner is positively or negatively chargeable is applied between the toner supply toner and the developing roller by a bias voltage distributing circuit.

Image developing device

An electrophotographic image developing device includes a fixed rotatable member and a suspended rotatable member reciprocally movable toward and away from the fixed rotatable member. Rotative power from a drive source is transmitted to the suspended rotatable member through a power transmitting unit which includes a coupling capable of absorbing axial misalignment between driver and driven shafts.

Image developing device for electrophotography

A developing device includes a developing sleeve driven to rotate for transporting a film of charged developer as carried thereon past a developing station where the film of developer is applied to an electrostatic latent image to have it developed. Also provided is a sponge roller pressed against and driven to rotate in the same rotating direction as that of the developing sleeve, so that the developer is supplied to the developing sleeve at one side of the contact between the developing sleeve and the sponge roller and any residual developer on the developing sleeve is removed at the other side of the contact. Preferably, a desired voltage difference is established between the developing sleeve and the sponge roller. Furthermore, the sponge roller is preferably so structured to have a sufficient conductivity level at least at its outer peripheral surface thereby allowing the residual charge on the developing sleeve to be discharged sufficiently.

Thin film developing device

An electrostatic latent image developing apparatus supplies toner to a latent image carrier such as a drum-shaped photosensitive body to visualize a latent image formed thereon. The toner is supplied by a rotating drum-shaped toner carrier having a portion confronting the photosensitive body adjacent thereto and another portion held in contact with toner contained in a toner container. The toner is electrostatically attracted to the toner carrier and transferred therefrom to the photosensitive body. The toner on the toner carrier is regulated into a thin toner layer by a toner layer regulating member that is resiliently held in sliding contact with the toner carrier. To prevent toner deposits from being attached to the toner layer regulating member, the toner layer regulating member is made of a material adapted to wear with the attached toner. In order to provide the toner layer regulating member with an ability to triboelectrically charge toner, whether chargeable to a polarity (-) or (+), or to control the amount of electricity on toner chargeable to a polarity (-) or (+) and prevent toner deposits from being attached to the toner layer regulating member, another material to control the amount of electricity on toner is mixed in the material which can be worn with the attached toner.

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Yokohama, Japan

Toshihiko Takaya