Ricoh Company, Ltd.

Makoto Hashimoto

Koichi Suzuki

Yoshiyuki Kobayashi

Shigeru Suzuki

Kyoji Omi

Yasumori Nagahara

Goro Mori

Kazuaki Tagawa

Yoshiharu Kagari

Either a single copy or a plurality of copies of an original document may be made. Making a single copy or the last copy of a plurality of copies comprises, during a first revolution of a photoconductive drum, electrostatically charging the drum, radiating a light image of the document onto the drum to form an electrostatic image, developing the electrostatic image using a magnetic brush to form a toner image, transferring the toner image to a copy sheet, electrostatically discharging the drum and uniformly radiating the drum with light to further discharge the same. During a second revolution of the drum the drum is cleaned with the same magnetic brush to remove residual toner, and again electrostatically discharged and uniformly radiated. During a third revolution of the drum the magnetic brush is again used for cleaning. For making all but the last of a plurality of copies, the drum is charged, imaged, transferred and electrostatically discharged during a first revolution thereof and cleaned with the magnetic bruch during a second revolution. Whether the process is used to make one or more copies, the same portion of the drum is always used. Subsequently, the drum rotation is indexed so that the next process will use a different portion of the drum.

Electrophotographic process

A magnetic brush development apparatus of the type comprising a plurality of rotatable, non-magnetic sleeves having stationary, inner magnets and capable of successively scooping up developer to the development section by the sleeves, wherein the magnets in the adjacent sleeves, located in the region where the developer is transferred from one sleeve to the next sleeve, are the same in polarity.

Magnetic brush development apparatus

The magnetic brush development apparatus comprises two magnetic rollers, namely a development roller for developing a latent electrostatic image and a developer feed roller for supplying a magnetic developer to the development roller. The quantity of the magnetic developer transferred from the developer feed roller to the development roller is initially regulated by a particular arrangement of the magnets disposed in the development roller and the developer feed roller. Furthermore, the quantity of the magnetic developer on the development roller is regulated by a doctor member prior to development. In order to keep the bulk density of the developer on the development roller constant, a preliminary pressure plate is provided for applying pressure to the developer on the development roller so that a uniform and high bulk density magnetic brush is formed on the development roller.

Magnetic brush development apparatus for an electrostatic copier

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Kawasaki, Japan

Makoto Hashimoto