Minolta Camera Kabushiki Kaisha

Masamichi Hayashi

Tomoji Murata

Hiroshi Ikeda

Yasuhiko Doi

Hiromitsu Saijo

Yasuo Goto

Shinya Matsuda

Shunji Yamamoto

Osamu Okada

Yukio Tokura

Masami Nakane

Takeji Morikawa

Takashi Hikosaka

Seiichi Sakurai

A developing device includes a casing having a sleeve chamber, an upper chamber and a lower chamber, a developing sleeve housed within the sleeve chamber with a portion of the outer peripheral surface spaced a distance from a photoreceptor drum to define a developing station, and a screw feeder operatively housed within each of the upper and lower chambers. A partition wall separates the upper and lower chambers from each other and has a port defined in a downstream end with respect to the direction of conveyance of the developing material within the lower chamber for placing the upper and lower chambers in communication with each other. A plurality of magnets are accommodated inside the developing sleeve so as to extend in a direction longitudinally of the developing sleeve while positioned circumferentially of the developing sleeve. A weak magnetic pole is disposed at a region confronting the screw feeder within the lower chamber and a strong magnetic pole is disposed at a region corresponding to the port in the partition wall member and longitudinally of the weak magnetic pole.

Developing device

An electrostatic latent image developing apparatus includes a rotatable developing sleeve, multiple fixed magnets provided in the developing sleeve and a brush-height regulating member provided opposite to the developing sleeve. One of the multiple magnets, which is provided opposite to the brush-height regulating member, is magnetized so that the region corresponding to 80% and more of the peak value in the magnetic force distribution curve of the magnet has a spread with a central angle of 20.degree. or greater on the exterior surface of the developing sleeve.

Electrostatic latent image developing apparatus

The invention is concerned with an apparatus for positioning optical elements of a lens for projecting an image of an original and a mirror for directing the image of the original from the lens toward a photosensitive medium. And the lens and mirror cooperate with movable optical members for scanning the original. The position of the optical elements are changed continuously or steplessly to a position corresponding to the newly selected magnification. For changing the magnification continuously, the lens in supported continuously shiftably along an optical path, and the mirror is supported continuously shiftably along the optical path from the lens and pivotally movable relative to the optical path. The lens and mirror are driven by a force of a single drive source via drive force transmitting mechanism.

Optical element positioning apparatus for use in electrophotographic

The present invention concerns with a slit illumination system for use in a copying machine or the like, which includes a light source, a first and second elliptical mirrors, a third plane mirror, and a supplemental mirror positioned behind the light source and between the first and second mirrors. The supplemental mirror directs the light which does not contribute to the illumination by the first and second mirror to the original through a light path extending directly to the original and/or a light path extending to the original through the third mirror.

Slit illumination system for copying machine and the like

A drive controlling mechanism of optical members for use in a copying apparatus, including an optical member, a pair of pulleys, a drive pulley for driving the pulleys for the rotation, a wire wound around the pulleys and the drive pulley and secured to the optical member, a pair of urging members for urging the pulleys in opposite directions for preventing the optical member from being brought out of contact with the stopper member, a plurality of stopper members for stopping the optical member at predetermined positions, a pair of detecting members for detecting swing movement of the pulleys, and a control circuit.

Drive controlling mechanism of optical member for use in copying

There is provided an arrangement for driving reciprocating members, which is for use in the optical system of an electrophotographic copying machine of the scanning exposure type. The optical system is actuated to have an initial velocity through the resilient force caused by each of spring members subsequent to alternate arrivals to respective end positions of scanning and returning movements. After having obtained the predetermined velocity either for the scanning, or the return operation, the optical system is actuated to be electrically driven for the purpose through the actuation of a clutch.

Means for driving reciprocating members

An electrophotographic copying apparatus incorporating therein an improved slit control device, which control device includes a blade member extending across the width of a photoreceptor drum. The width of the blade member in a direction normal to the axis of the photoreceptor drum is so arranged as to gradually increase toward its opposite ends in comparison with a generally uniform width in its central portion so as to form a slit which is wide in the central portion and gradually narrowed toward opposite ends, by which arrangement a sharp and definite image of an original is formed even on a photoreceptor drum of small diameter.

Electrophotographic copying apparatus with novel exposure slit means

The electrophotographic copying machine of the present disclosure includes a slit mechanism having two different forms of slits, an optical device to project the image of the original to be copied onto a photoreceptor surface a shifting mechanism for shifting the optical device between a first position suitable for performing an equal size copying operation and a second position suitable for performing a different size copying operation, such as a reduced size copying operation. During the equal size copying operation, the slit mechanism provides a slit having a large size, while during the other size copying operation, for example, a reduced size copying operation, the slit mechanism provides a slit having a different size, for example a small size, so as to maintain the distribution of the amount of exposure on the photoreceptor surface in a predetermined distribution regardless of the type of copying operation.

Electrophotographic copying machine of a multi-size copying type

In a transfer type electrophotographic copying apparatus which comprises a reciprocating platform for supporting an original to be copied, a rotatable photoreceptor drum of a small diameter, and processing devices of small size disposed around the photoreceptor drum for compact size of the copying apparatus, an improved transfer device and a transferred image disturbance prevention device are further included for efficient copying operations.

Growing community of inventors

Aichi, Japan

Masamichi Hayashi