Minolta Camera Kabushiki Kaisha

Takao Fujiwara

Takaji Kurita

Kenichi Wada

Hiroshi Murasaki

Yuji Enoguchi

Masaya Ogawa

Susumu Tanaka

Hidetoshi Kawabata

Katsuhiko Takeda

Kouji Ito

Akihiro Nishida

Hideo Kitakubo

Takashi Kuwako

Kidetoshi Kawabata

Tatsuya Okada

Yoshitaro Furukawa

A developing device for color copiers and the like. The developing device has a plurality of developing units, each of which has a developing roller for developing an electrostatic latent image formed on an image carrier; a developing unit switching device for moving the developing units linearly and for selecting one of the developing units to oppose the image carrier; a fixed driving source for generating a driving force to drive the developing rollers; wrapping connecting apparatus which has a wrapping member and movable rotating structure having at least one rotating member and movable together with the developing units, the wrapping connecting apparatus being for conveying the driving force to the movable rotating structure; and a plurality of clutches, each of which is provided for one developing unit and is switched to a first state wherein the clutch conveys the driving force from the movable rotating structure to the developing roller and to a second state wherein there is no conveyance.

Developing device drive mechanism for selecting and powering developing

An image forming method and apparatus for forming a reproduced color image in which the sequence of supply of the toners of different colors onto the latent image carrier is selected according to the color information of the document to be copied. A controller is provided so as to control the various colored developers in a sequence in which the developers providing the different color toners are operated so that the second toner color overlaps the first toneer color and the first toner color can overlap on the second toner color through a series of colors.

Multi-color image forming method and an apparatus therefor

An image forming method and an apparatus therefor for forming a reproduced color image on a recording medium by repeating a process of forming on a latent image carrier an electrostatic latent image corresponding to a document image through an image exposure, depositing one of at least yellow, magenta and cyan toners on the electrostatic latent image, wherein a color which is read as a mixture of magenta and cyan is deposited as magenta or cyan according to the proportion of mixing of magenta and cyan in the mixed color.

Multicolored image forming method and apparatus therefor

An image forming apparatus which includes a color editing function is provided with two developing units, each of the developing units contain an impeding device for impeding flow of the developer as it is transported on a peripheral surface of the developing sleeve locally in the axial direction of the roller. An image editing device is provided for specifying an optical area of a desired image to be produced and a controller is provided for controlling the developing units so as to permit development of a specified area by one developing unit and to develop any unspecified area by the other developing unit.

Image forming apparatus having color editing function

An optical illumination device for a copying apparatus which includes a light source, a series of reflectors, and a light detecting member for detecting the amount of light reflected off of the original document to control the intensity of the light source. The series of reflectors includes two reflectors on the opposite side of the optical path from the light source which are integrally formed to provide an L-shape configuration in cross section. One of the integrally formed reflectors reflects the light from the document onto the light detecting member.

Optical illumination device for use in a copying apparatus

A toner scattering prevention device for preventing toner from scattering out of a developing device or a cleaning device. The device includes a toner sealing plate and a clamp arrangement. The clamp arrangement prevents the toner sealing plate from being displaced in a direction at right angles to a widthwise direction of a toner image support member but allows displacement of the toner sealing plate, resulting from expansion or shrinkage of the toner sealing plate in the widthwise direction of the toner image support member due to environmental changes, aging, etc.

Toner scattering prevention device

A photocopying machine equipped with a variable magnification arrangement including a cassette containing large-size copy paper and positioned to permit lengthways transport of copy paper through the machine and a cassette containing small-size copy paper and positioned to permit sideways transport of copy paper through the machine. The cassettes comprise actuation elements which actuate different combinations of switches in a control circuit, which in response causes adjustment of positions of photocopying machine elements for production of photocopies of different magnifications and causes selective forwarding of copy paper of the required size from a cassette.

Photocopying machine equipped with variable magnification arrangement

An electrophotographic copying apparatus has a drum with an endless photoconductive material on its periphery and has arranged around the periphery of the photoconductive drum an eraser unit, a charging unit, a slit exposure unit, a developing unit, a transfer unit and a cleaning unit disposed within or close to the developing unit. The charging, exposure and developing units are operable during the first revolution of the photoconductive drum to form an image thereon, the cleaning unit being operable to clean the surface of the photoconductive drum during the second revolution thereof. The photoconductive drum in the course of the second revolution is adapted to rotate until the rear end of the image formed on the photoconductive drum has passed the charging unit, whereupon one copying cycle is completed. The front end of the image to be subsequently formed can be positioned on a portion of the photoconductive drum other than where the front end of the image formed during the abovementioned cycle is positioned.

Electrophotographic copying apparatus

In an image transfer type copying apparatus including an image exposure station having an exposure lamp for successively projecting an image of the original onto a photosensitive member, charging means disposed around the photosensitive member for charging the surface of the photosensitive member, a developing station for developing an electrostatic latent image, a transfer station for transferring the developed image onto a copying member and a cleaning station for cleaning the residual toner, the improvement consists of an erasing station for erasing unnecessary charges formed by the charging station which remains operative even after formation of the latent image. A controller energizes the erasing lamp while the exposure lamp is still lit with the exposure lamp being effectively energized even after completion of exposure of the image. The erasing station is energized when the trailing edge of the latent image reaches a position not influenced by the erasing operation.

Erasing device for image transfer type copying apparatus

An electrophotographic copying apparatus which includes a thin sheet original transporting device having transporting rollers and disposed adjacent to a transparent platform for holding thick originals at the upper portion of the copying apparatus, and an image forming optical system moving device for moving the optical system from a scanning starting position for thick original copying to a stationary optical system position for thin sheet original copying in association with a change-over of operation from copying a thick original to copying a thin sheet original in order to eliminate disadvantages inherent in exposures in conventional copying apparatuses, and the distance between first and second reflecting mirrors of the optical system at the scanning starting position for copying thick originals is set to be less than that when the optical system is in the stationary position for reduction of the size of the copying apparatus.

Electrophotographic copying apparatus for copying thick and thin

An electrophotographic copying apparatus which is equipped with an improved arrangement for removing jammed copy paper. The apparatus is provided with a photoreceptor and a developing device combined into one unit which can be withdrawn to provide sufficient space for removing jammed copy paper, and is also provided with copy paper transporting members, a corona charger, a transfer charger, a copy paper separating claw etc. which can be moved away from a transfer section in one operation for facilitating access to the jammed copy paper in an efficient manner in the case of copy paper jamming. The transfer charger is covered when it is moved away from the transfer section to protect it from possible damage.

The heat and pressure rolls of a fusing apparatus for an electrophotographic copying machine are shifted into pressure contact with one another while a support sheet bearing a toner powder image passes therebetween, and are separated while the sheet is not therebetween. A driving mechanism drives both rolls when not in contact, while one of the rolls drives the other while in pressure contact. A shifting mechanism is actuated by a sheet detector for shifting the rolls into and out of contact. In another embodiment, the rolls are in light rolling contact, with no sheet passing therebetween, under the weight of one of the rolls idly mounted in place. A pressing mechanism presses the rolls into pressure contact, upon actuation by a sheet detector, while the sheet passes between the rolls.

Electrophotographic fusing apparatus

A belt support structure which telescopically movably supports a belt assembly in a photoelectrostatic copying machine. The belt support structure has first guide rails secured at at least two spaced points thereof to a wall or framework of the housing structure for the copying machine, second guide rails respectively telescopically movably mounted on the first guide rails and third guide rails telescopically mounted on the second guide rails. The third guide rails carry the belt assembly for pivotal movement between operative and released positions. When the belt assembly is in the released position outside the housing structure, replacement of the used photoreceptor belt, inspection, repair or cleaning of all operating elements of the copying machine arranged around the photoreceptor within the housing structure can be facilitated.

Belt support structure in copying machine

In an electrophotographic copying machine having a transparent support for support thereon the original to be copied, an illumination device for illuminating the original on the transparent support and a photoreceptor surface adapted to be driven past charging, exposure, developing, transfer and cleaning stations, a discharging device for extinguishing unnecessary electrostatic charge on the photoreceptor surface which is formed at an area between each two adjacent areas to be optically exposed to the incoming light, which discharging device has at least one light guide having one end situated adjacent an intercepting mechanism and the other end situated in the vicinity of the photoreceptor surface. The intercepting mechanism is brought into operation to intercept passage of discharging light towards the photoreceptor surface.

Device for extinguishing unnecessary electrostatic charge in

A developing material applicator for use in a photoelectrostatic copying machine to apply or depost a uniform layer of toner particles on the electrostatic latent image carried on a photoreceptor surface. The developing applicator comprises a housing structure having two compartments divided by a partition wall. Within a first one of the compartments, there is provided an impeller and a supply roll assembly for transferrence of the developing material from the first one of the compartments to the other second compartment. Within the second compartment and adjacent the supply roll assembly, there is positioned a clipping roll assembly for clipping the developing material carried by the supply roll assembly. An applicator is positioned within the second compartment at a developing zone where the photoreceptor surface is moved. The applicator applies the developing material over the photoreceptor surface after it has received the developing material from the clipping roll assembly.

Growing community of inventors

Sakai, Japan

Takao Fujiwara