Oki Data Corporation

Yoshitatsu Okiyama

Shinichi Murakami

Ken Kikuchi

Masato Sakai

Noboru Otaki

Kazuyoshi Yoshida

Makoto Yabuki

Fumiaki Yoshida

Syuichiro Ogata

Hiroyuki Inoue

Hisao Ono

Shigeki Nakajima

Yoshiharu Momiyama

Takashi Itaya

Kuniharu Hayashi

Toru Ishihara

Kazuhiko Nagaoka

Atsushi Kurabayashi

Masanori Maekawa

Masato Nagata

Hiroyuki Yajima

Norio Ebata

Makoto Otake

Tetsu Koyama

Junichi Ito

Teruaki Kuroda

Koji Ida

Syuiti Fujikura

Shuichiro Ogata

A toner cartridge includes a housing and a shutter inserted therein. The housing has a first partially cylindrical wall and a box-like portion that communicates with the first partially cylindrical wall. The shutter has a second partially cylindrical wall inserted inside the first partially cylindrical wall such that the second partially cylindrical wall is slidable on and concentric with an inner surface of the first partially cylindrical wall. The shutter has a supporting member that engages the housing to support the shutter such that the second partially cylindrical wall is in pressure contact with the first partially cylindrical wall. The supporting member may be in the shape of an arcuate member or ring that engages a part of the box-like portion so that the shutter is rotatably supported in the housing by the part and the first partially cylindrical wall. The housing has a projection or rib that inwardly projects toward the first partially cylindrical wall. The projection abuts the arcuate member so that the shutter is rotatably supported in the housing by the arcuate member and the first partially cylindrical wall.

Toner cartridge

To prevent irregular print density resulting from an uneven toner layer, a developer remover which may be a plurality of cylindrical members formed like rollers, a net-like member, roller member and/or a contact member, are arranged in a manner to contact a sponge roller When residual toner on the surface of a developing roller is scraped off by the sponge roller the developer remover pushes the toner away without allowing the toner to clot inside the sponge roller Consequently, the sponge roller's performance to remove toner from itself to the developing roller can be preserved for a long time.

Developing device having means to remove developer from a developer supplying member

A color image forming apparatus includes a carrier belt which runs along a transport path of a recording medium to transport the recording medium. A number of image-forming sections are aligned in the transport path. Each of the plurality of image-forming sections forms a toner image of a corresponding color included in an image signal. A plurality of transfer units are provided, with each being disposed to oppose a corresponding one of the number of image-forming sections. Each of the number of transfer units transferring the toner image of the corresponding color to the recording medium. A fixing unit is provided that fixes the toner image to the recording medium. A controller is provided that detects a number of colors in the image signal. The controller sets one set of speeds from a plurality of different sets of speeds in accordance with the number of colors. Each set of speeds includes a speed of the carrier belt, a speed at which each of the image-forming sections forms a respective toner image of a corresponding color, and a speed of the fixing unit. The speed of the carrier belt, the speed at which each of the image-forming sections forms a respective toner image of a corresponding color, and the speed of the fixing unit of any one respective set of speeds are substantially equal to each other.

Color image forming apparatus having a controller for setting printing

A medium-transporting apparatus has a carrier belt which carries a medium attracted thereto. An attraction roller is disposed in an abutting relation with the carrier belt. The print medium is sandwiched and passes between the attraction roller and the carrier belt. The attraction roller has a low resistance resilient roller and a high resistance member of an insulating material or a semiconductive material formed on the surface of the resilient roller. The member has a higher electrical resistance than the print medium and prevents current from flowing through areas in which the print medium is absent between the attraction roller and the carrier belt. The attraction roller receives a high voltage so that a discharge occurs between the attraction roller and the print medium when the print medium separates from the attraction roller as the print medium passes between the attraction roller and the carrier belt, thereby depositing charges on the print medium so that the print medium is electrostatically attracted to the carrier belt.

Medium transporting apparatus having attraction member

An image forming apparatus such as color electrophotographic printer has a plurality of image forming stations. Each image forming station includes an image forming cartridge and a toner cartridge mounted therein. The toner cartridge has a corresponding first engagement portion. The image forming cartridge has a receiving section with a corresponding second engagement portion. The receiving section detachably receives the corresponding toner cartridge therein with the second engagement portion fittingly engaging the first engagement portion. The first and second engagement portions are of a construction that they can be polarized such that the first engagement portions engage the second engagement portions in different engagement relations when the devices are received in the receiving sections, each of the toner cartridges being received in a corresponding one of the receiving sections. Such an engagement construction may also be applicable to the image forming cartridge and the receiving section formed in the body of the printer which receives the image forming cartridge. The image forming cartridges and the receiving sections are polarized such that they are fittingly engaged with each other in different engagement relations.

Image forming apparatus having a plurality of image forming stations

A belt unit has a drive roller, a driven roller, and a tension roller. An endless belt is mounted about the drive roller, driven roller, and tension roller. When the drive roller is driven by a motor, the endless belt runs with a print medium placed thereon. The tension roller longitudinally extends in a direction perpendicular to the direction in which the belt runs. First and second support members are pivotally mounted on a frame and support the tension roller between the first and second supports. The spring urges the support members so that the tension roller exerts tension on the belt. A coupling member such as a rod, wire, and plate couples the first support member to the second support member, so that a first pivotal movement of one of the first and second support members causes a second pivotal movement of the other of the first and second support members, the first and second pivotal movements applying a substantially same urging force to the belt.

Belt unit

A color image forming apparatus provides the prolonged life of the photosensitive drums, carrier belt, and toner of the respective colors and improves the quality of the printed color image. A carrier belt transports a recording medium placed thereon so that the recording medium passes through a plurality of printing mechanisms which print images of different colors on the recording medium in superposition. Each printing mechanism prints an image of a corresponding color. The printing mechanism is adapted to be moved into its operative position where the photosensitive drum of the printing mechanism is in contact with the carrier belt to print the image on the recording medium, and into its non-operative position where the photosensitive drum of the printing mechanism is not in contact with the carrier belt. A controller receives print data from a host device such as a personal computer and checks each page of the print data to determine whether any one of a predetermined plurality of colors is missing in the page. If a particular color is missing in the print data, then the controller outputs an UP signal to a positioning mechanism for a corresponding printing mechanism. If the color is not missing, then the controller outputs a DOWN signal. The printing mechanism moves a corresponding printing mechanism into the operative position if the UP signal is received from the controller and into its operative position if the DOWN signal is received.

Color image forming apparatus having a printing mechanism selectively

An image recording apparatus includes a rotating photosensitive drum, a developing unit, a neutralizing device, and a transferring device. An electrostatic latent image is formed on a charged surface of the rotating photosensitive drum, the electrostatic latent image being developed by a developing unit and subsequently transferred by a transferring device to a print medium. The neutralizing device neutralizes the charged surface of the photosensitive drum at the point on the surface disposed downstream of the developing unit and upstream of the transferring device with respect to rotation of the photosensitive drum. A controller controls the neutralizing device according to characteristics of the print medium such as size, material, insulation, and transparency. The neutralizing device may be operated in different modes. For example, the neutralizing device may neutralize an entirety of the charged surface of the photosensitive drum only if the print medium is of a predetermined characteristic, i.e., an insulating sheet such as a transparent OHP sheet or may neutralize only selected parts of the charged surface of the photosensitive drum according to a width of the print medium.

Image recording apparatus having a neutralizing device

A method of forming an electrostatic latent image includes printing operation and toner recovering operation. The printing operation includes charging, forming an electrostatic latent image, developing, and transferring operations. The toner recovering operation includes the step of charging the photosensitive drum in timed relation to the rotation of the photosensitive drum after printing operation so that reversely charged toner deposited on the charging roller migrates from the charging roller to the photosensitive drum. The toner migrated from the charging roller to the photosensitive drum is recovered into a developer. An apparatus for forming an image includes a charging roller, photosensitive drum, developing roller, and transfer roller. The apparatus further includes a reversely-charged-toner recovering device which causes the photosensitive drum to be charged in timed relation to the rotation of the photosensitive drum after printing operation so that the reversely charged toner deposited on the charging roller migrates to the photosensitive drum. The developer recovers the toner which has migrated to the photosensitive drum from the charging roller.

Method and apparatus for forming an electrostatic latent image with

A method of forming an electrostatic latent image includes printing operation and toner recovering operation. the printing operation includes charging, forming an electrostatic latent image, developing, and transferring operations. The toner recovering operation includes the step of charging the photosensitive drum in timed relation to the rotation of the photosensitive drum after printing operation so that reversely charged toner deposited on the charging roller migrates from the charging roller to the photosensitive drum. The toner migrated from the charging roller to the photosensitive drum is recovered into a developer. An apparatus for forming an image includes a charging roller, photosensitive drum, developing roller, and transfer roller. The apparatus further includes a reversely-charged-toner recovering device which causes the photosensitive drum to be charged in timed relation to the rotation of the photosensitive drum after printing operation so that the reversely charged toner deposited on the charging roller migrates to the photosensitive drum. The developer recovers the toner which has migrated to the photosensitive drum from the charging roller.

An electrophotographic recording apparatus that removes reverse-charged toner that is charged with a polarity opposite to a polarity of a normal-charged toner. The apparatus includes a carrier belt; a transfer roller for carrying the toner adhering to the surface of the photosensitive body toward the carrier belt; a transfer power supply for applying to the transfer roller a first voltage that causes the normal-charged toner adhering to the surface of the photosensitive body to be transferred to the recording medium on the carrier belt, and a second voltage, of opposite polarity to the first voltage, that causes the reverse-charged toner adhering to the surface of the photosensitive body to be transferred to the carrier belt; and a carrier belt cleaning blade. A control circuit controls an operation of the transfer power supply, whereby the first voltage is applied to the transfer roller during an image-forming stage, and the second voltage is applied to the transfer roller during a reverse-charged toner removing stage. For example, the normal-charged toner may have a negative polarity, the reverse-charged toner may have a positive polarity, the first voltage may be positive, and the second voltage may be negative.

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Tokyo, Japan

Yoshitatsu Okiyama