Minolta Camera Kabushiki Kaisha

Hiroaki Mizunoe

Tateki Oka

Kenichi Wada

Susumu Tanaka

Kenji Tabuchi

Takaji Kurita

Teizo Kushima

Yoshihiro Isono

An electrographic developing method comprising forming a magnetic brush of a developer composed of at least two components of insulating toner particles and insulating carrier granules, and brushing a surface bearing an electrostatic latent image with the brush to render the latent image visible, the carrier granules having the properties of (1) triboelectrifying the toner particles to a polarity suitable for developing the latent image by coming into frictional contact with the toner particles, (2) being magnetic, (3) having a resistivity of at least 10.sup.12 ohm-cm, and (4) being 5 to 40 .mu.m in size.

Electrographic developing method

A dry process developing apparatus for use in an electrophotographic copying machine which includes a developing non-magnetizable sleeve and a multipolar magnet member arranged to be rotated in the same direction at different speeds, the speed of rotation of the developing sleeve causing movement of those particles of the developing material which at the most are only slightly affected by the multipolar magnet member in the direction of rotation of the sleeve, and the speed of rotation of the multipolar magnet causing the movement of particles of developing material affected by the magnet around the sleeve in a direction of rotation opposite that of the magnet and at a speed greater than the speed of the developing sleeve. Scraping members are provided for sliding contact with the peripheral surface of the developing sleeve in the directions against and following the direction of rotation of the developing sleeve.

Dry process developing apparatus for use in electrophotographic copying

An electrophotographic copying apparatus of the slit exposure type which includes a scanning box having image forming elements such as a photoreceptor drum, a corona charger, an optical system, and a transfer member, etc. incorporated therein. The photoreceptor drum is rotated in synchronization with the movement of the scanning box, while copy paper is transported by the direction of movement of the scanning box at a speed equivalent to the sum of the moving speed of the scanning box and the circumferential speed of the photoreceptor drum for causing the copy paper to contact the photoreceptor surface in synchronization with each other so that the image of an original formed on the photoreceptor surface is transferred onto the copy paper. The optical system includes an illuminating device which directs light rays toward the original being copied and also at a position on the photoreceptor surface following image transfer for erasing the residual charges remaining on the photoreceptor surface.

Electrophotographic copying apparatus

Optical projection apparatus for an image transfer type electrophotographic copier, wherein prism-shaped reflecting members are disposed at both ends of an optical fiber type image transmitter formed by a bundle of optical fibers having graded refractive indexes, so as to refract an optical path, whereby an optical image of an original document is projected towards the side peripheral surface of a photosensitive drum, reducing the height of the optical projection apparatus and thus providing a compact copier. The optical projection apparatus is so constructed that the image transmitter formed by a bundle of optical fibers having graded refractive indexes is fixedly held between the prism-shaped reflecting members including a prism portion and a support or body portion integrally formed therewith.

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Sakai, Japan

Hiroaki Mizunoe