Minolta Camera Kabushiki Kaisha

Hiroshi Ikeda

Kenichi Arai

Masamichi Hayashi

Shinya Matsuda

Takaji Kurita

Yoshihisa Kawai

Hiromitsu Saijo

Yasuhiko Doi

Masaru Komura

Shin Miyata

Koji Takeuchi

Tetsuya Utsumi

Seiichi Sakurai

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 disclosed relates to a drive mechanism for an image transfer type copying apparatus which comprises first and second drive sources independent of one another. The first drive source is for driving photosensitive member and scanning movement of original scanning means whereas the second drive source is for driving developing means and return movement of original scanning means so as to prevent slippages in synchronism and in image transfer cause by a shock or impact generated at the time of initiation of return movement of scanning means or at the times of initiation and stop of the developing means.

Drive mechanism for an image transfer type copying apparatus

For end positions of the elements of an minute adjustment of the optical system set for magnifications having the same conjugate distance, the focal adjustment for one of two magnification modes is first performed by adjusting the position of a mirror assembly, and the adjustment for the other magnification mode is performed only by adjusting the end position of the lens assembly at the position for the other magnification mode. Hence, during the change of the magnification modes from one to the other the position of the mirror assembly per se remains unchanged.

Optical assembly for use in copying machine

An electrophotographic copying machine comprises a transparent support for the support of an original to be copied, a photo-receptor, an optical projecting system for projecting an image of the original onto the photo-receptor and an exposure adjustment for controlling a pattern of distribution on the photo-receptor of rays of light carrying the image of the original. The optical projecting system includes a projecting lens assembly supported for movement between at least first and second positions wherein the image of the original can be reproduced on a copying paper in different magnifications. The exposure adjustment is positioned between the transparent support and the optical projecting system and is comprised of a fixedly supported light shielding member.

Electrophotographic copying machine

A slit exposure scanning type electrophotographic copying apparatus equipped with a braking device for the scanning system. The braking device includes a brake shaft rotatably disposed in a driving mechanism of the scanning system, and a spring member which is mounted on the brake shaft and is adapted to impart a braking force at least at a scanning starting position which is decreased in its braking force following starting of the scanning.

Electrophotographic copying apparatus equipped with improved braking

A lens positioning device for an electrophotographic copying machine having at least three magnification modes and including a projecting lens unit movable along the optical axis between extreme positions representing the largest and smallest magnifications through an intermediate position representing a magnification substantially intermediately between the largest and smallest magnifications. The lens positioning device comprises a stopper mechanism for trapping the projecting lens unit at the intermediate position accurately and exactly. This stopper mechanism includes at least one blocking element pivotally carried by a movable block and operable to halt the movement of the projecting lens unit when the movable block is moved to a position where the blocking element is ready to engage the projecting lens unit.

Optical apparatus for electrophotographic copying machine

A variable magnification electrophotographic copying apparatus includes an original holder and an original scanning mechanism of the original holder advancing type or of the scanning mirror advancing type. The focus of the image projector lens is adjusted concurrently with the speed of the scanning mirror or original carrier relative to the photosensitive drum speed to adjust the image magnification ratio. Copy paper is withdrawn from a roll thereof and advanced past a cutter through an image transfer station adjacent to the photosensitive drum. The cutter is actuated in response to the position of an indexing member movable along the length of the original and the relative speed of movement of the original or scanning mirror to actuate the cutter so as to cut the copy paper to a length corresponding to the length of the image of the original on the copy paper. The copy paper feed is synchronized with the image scanning so that the leading edge of the image coincides with the leading edge of the copy paper. Switches are actuated by the indexing member carried by the moving original holder or the indexing member of a stationary original holder carries the switches actuated by the scanning mirror carriage and controls the actuation of the cutter.

Scanning type variable magnification electrophotographic copying machine

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

A slit-scanning type optical copying apparatus, wherein successive increments of the surface of an original are scanned by reciprocating an original-carrying support or an original-image scanning mirror, so that an original image is focused on a photosensitive member moving or turning at a given speed or at a given R.P.M. in a given direction, through a projecting optical system including an objective lens. In this optical copying apparatus, the projecting optical system comprises: a single objective lens; a roof reflecting member having adjoining reflecting surfaces making a right angle therebetween, the aforesaid reflecting member being positioned in the rear of the objective lens; a single half-mirror positioned in the optical path in the front of the objective lens and oriented to direct projecting beams from the original onto the lens and to direct projecting beams from the lens onto the photosensitive member, respectively; and means for turning the reflecting member through an angle of 90.degree. in response to the advancing and returning movements of the original carrying support or original-image scanning mirror.

Optical copying apparatus

A transfer type electrophotographic copying apparatus for high speed copying system which includes a photoconductive photoreceptor in the form of an endless belt and movably suspended by a plurality of rollers so as to provide a plurality of flat surfaces. A flat portion which is formed on the photoreceptor belt facing a transfer corona charger and which is directed approximately parallel to a path of a copy paper sheet is effective for shortening the length of the paper path and for improving transferred images, while blower means disposed in a fixing device is adapted to assist in the separation of the copied paper from the photoreceptor belt in normal copying operation, and to direct cooling air to the fixing device in case of paper jamming. Heat shielding means is disposed between the fixing device and the photoreceptor belt.

Transfer type electrophotographic copying apparatus

A lens selection device for placing any one of three or more magnification lenses in an operative position where its optical axis aligns with a respective reference axis, a selected lens being shifted along a fixed path from a retracted position to the operative position thereof by separate drive means numbering one less than the quantity of the lenses. In the case of three lenses, for instance, a first drive means is used to shift a first lens, a second drive means is used to shift a second lens, and a follower means coupled with a third lens is used to shift it to its operative position when the first (or the second) lens is driven to its retracted position.

Lens selection device

An original document holder for application in electrophotographic copiers of the instantaneous exposure type which use high intensity xenon flash lamps. The holder is a box-shaped cover with at least one movable, spring-closed side such that extra large, thick documents such as books may be copied without danger of light leakage by virtue of light-tight engagement of the movable side with the projecting portions of such documents.

Growing community of inventors

Aichi, Japan

Hiroshi Ikeda