Ricoh Company, Ltd.

Takeshi Motohashi

Tsuyoshi Deki

Nobuo Iwata

Takahiro Tamiya

Noriyuki Kimura

Yoshiaki Tanaka

Hiroyuki Matsushiro

Tomonori Yabuta

Hiroshi Hosokawa

Hideo Aoki

Shigeo Kurotaka

Katsuhiro Kosuge

Hideaki Mochimaru

Hideto Miyazaki

Takashi Kimura

Eiichi Sasaki

Shigekazu Enoki

Nobuhiro Makita

Hideyuki Takemoto

Hiromi Takada

Hirotaka Hatta

Yutaka Shio

Yasuhiro Sagawa

Masayoshi Miyamoto

Takami Suzuki

Hiroyuki Idenawa

Tadaaki Kanno

Yasuyuki Nukaya

Toshio Shimazaki

Hajime Kanda

Shunichi Ogawa

Mamoru Takezawa

Shingo Kato

Hisao Ishizu

Shoji Yanagida

Tomoyuki Moriya

Fumihiro Kitahara

Tomio Wakabayashi

Shingo Katou

Iwao Mitsuki

Osamu Kuramochi

Makoto Yumoto

Koyo Hariyama

Hiroyuki Goto

Masashi Takiguchi

Takanori Yamaki

Takahiro Yagisita

Tomoo Sankoda

Eiji Hashimoto

An image forming apparatus includes a first sheet path, a first sheet transfer mechanism, an ejection mechanism, a second sheet path, and a sheet flipping mechanism. The first sheet path is in a first side of the image forming apparatus. The first sheet transfer mechanism sends recording sheets from a sheet cassette through the first sheet path. The ejection mechanism switches between an ejection process and a duplex recording process. The second sheet path receives the recording sheet from the ejection mechanism and returns it to the image recording mechanism. The second sheet path is on the other side of the apparatus than the first side in which the first sheet path is arranged. The sheet flipping mechanism flips the recording sheet and has a flipping space in which the recording sheet is flipped without coming outside of the image forming apparatus. The ejection mechanism, the second sheet path, and the sheet flipping mechanism are located in a separate add-on unit. The second sheet path has openable/closable side guides for operator access.

Image forming apparatus conveniently upgradable to a duplex image forming apparatus

A color image forming apparatus capable of superposing toner images of respective colors in accurate register by preventing an exposing position from being displaced in the subscanning direction. The rotation phase of a polygonal mirror is controlled on the basis of the mark detection timing of a mark sensor. Hence, the exposing position in the subscanning direction is prevented from being displaced without regard to irregularities in the circumferential length and feed speed of an intermediate image transfer belt.

Color image forming apparatus with polygonal mirror rotation phase control

A color printer for forming color toner images on a sheet of paper includes a photoconductive belt for bearing an electrostatic latent image thereon, a plurality of developing devices, and an intermediate transfer belt for forming composite toner images thereon. The intermediate transfer belt and the developing devices face each other across the photoconductive belt. The color printer further includes a front frame which is provided adjacent the intermediate transfer medium, a paper feed device which is provided in a lower position of the apparatus, and a paper output tray which is provided in a upper position of the apparatus. A paper transporting path between the paper feed device and the paper output tray is provided between the intermediate transfer belt and the front frame.

Color image forming apparatus including process cartridge

A color printer including a photoconductive belt, a black developing unit which is located adjacent the photoconductive belt and a revolving type developing unit which is located adjacent the photoconductive belt and has a developing position on the photoconductive belt which is different from that of the black developing unit. The revolving type developing unit has a yellow developing device, a magenta developing device and a cyan developing device, each including a detachable toner cartridge by which yellow toner, magenta toner and cyan toner is replenished. The black developing unit is replaceable independent of the revolving type developing unit by being removably mounted on a removable frame on which the revolving type developing unit is mounted. Both developing units are removable from the color printer as a body by removal of the removable frame from the color printer.

Developing device for image forming apparatus

In a paper conveyer of an image forming apparatus, a transfer operation is performed by a transfer roller and an unfixed image in the transfer operation is carried onto the lower side of a transfer paper sheet. The transfer paper sheet is conveyed to a fixing device constructed by a fixing roller and a pressurizing roller. A hardness of the fixing roller is smaller than that of the pressurizing roller, while a nipping portion of the fixing and pressurizing rollers is formed in a concave shape. The fixing and pressurizing rollers are arranged such that a nipping inlet port point of the fixing and pressurizing rollers is located in the vicinity of a line of a conveying locus of a thin transfer paper sheet. A paper guide plate guides the transfer paper sheet to the nipping inlet port. In this construction, a transferred paper sheet is conveyed such that this transferred paper sheet is reliably fed into the nipping portion of the fixing device, and it is possible to prevent an image rub, wrinkles, a jam, etc. from being caused.

Paper conveyer of image forming apparatus which conveys paper to a

In an image forming apparatus of the type sequentially forming powder images of different colors on an image carrier, and sequentially transferring them to an acceptor one above the other (primary transfer), an image transfer method is disclosed which prevents transfer dust from being transferred to the acceptor at the time of the primary transfer. During the primary transfer, a bias potential V.sub.1 is applied to one of two conductors located at an upstream side. The potential V.sub.1 has the same polarity as the charged powder carried on the image carrier. A potential V.sub.2 is applied to the other conductor at a downstream side and provided with a polarity opposite to the polarity of the charged powder. Every time the primary transfer is repeated, the potentials V.sub.l and V.sub.2 are respectively sequentially shifted toward the polarity of the powder and toward the polarity opposite to the polarity of the powder.

Image transfer method for an image forming apparatus

A developing device which is particularly advantageous from the standpoint of avoiding leakage or scattering of toner. The developing device is additionally advantageous in allowing for a compact design while reliably supplying toner to the complete area of a photosensitive member upon which a latent image is formed. The developing device includes a toner container having an opening in a lower part thereof, through which toner falls. A magnet bar is provided below the opening, with a developing grid covering a portion of the magnet bar. The magnet bar forms a magnetic toner brush which penetrates through holes in the developing grid, with the magnetic toner brush and grid cooperating to prevent excessive toner from falling through the opening and thus preventing excessive toner from scattering outside the developing device.

Developing device for an image forming apparatus

A laser printer or like electrostatic recording apparatus of the type developing an electrostatic latent image provided on a photoconductive drum by toner which is conveyed by a developing roller. Various devices of the apparatus including the photoconductive drum and developing roller are separated into an upper and a lower unit which are openable away from each other. A photoconductive drum assembly including the photoconductive element and a developing assembly including the developing roller are individually detachable from a body of the apparatus. Various measures are taken to enhance stable and safe operation, miniaturization, easy maintenance, operability, service life, and image quality.

Electrostatic recording apparatus

A printing device such as a printer of the type using a type wheel in which a carriage is loaded with a printing mechanism and movable along a carrier to allow the printing mechanism to print out data on a paper, which is wrapped around a platen. The carrier and/or the carriage is produced by press-forming a single sheet metal to cut down the production cost and the number of structural elements of the printer.

Printing device with carriage and carrier therefor each integrally

A printing apparatus having a printing unit and a paper supply unit mounted thereon is provided with a control means which controls a carriage such that it occupies a position other than its home position when a front end of a paper passes through a guide member for guiding a printed paper. The apparatus can be provided with a movable paper guide which is movable between a use position and a wait position. A clutch mechanism is provided for transferring rotation from the platen to a feed roller associated with the paper supply unit.

Paper feed roller drive system for a printer

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Kawasaki, Japan

Takeshi Motohashi