Sharp Kabushiki Kaisha Corporation

Tsutomu Nagata

Jun Yamaguchi

Naotaka Funayama

Yasuyuki Ishiguro

Toshio Nishino

Yoshiaki Sanada

Takahiko Kimura

Hiroshi Tanisawa

Yoshinori Otsuka

Masatoshi Kaneshige

Hiroshige Araki

Haruko Yoneda

Hiroshi Kawahito

Keiji Kato

Shoji Tomita

Takashi Hirota

Akira Nakakuma

Shuhichi Morikuni

Toru Yosioka

An image forming apparatus is provided having a mechanism that toner density of a toner image is automatically adjusted based on a toner patch. In an image forming apparatus including a document conveying section, a document reading section, an image forming section, a sheet discharging section, a sheet feeding section, a patch density detecting section, and a toner density adjusting section for adjusting density of a toner image depending on a result detected by the patch density detecting section, there are further provided a patch forming section for forming a toner patch, an operation detecting section for detecting an operating state of the patch density detecting section, and a patch printing section for printing the toner patch in response to such a result detected by the operation detecting section that the patch density detecting section does not properly operate, thereby adjusting the toner density based on the patch image.

Image forming apparatus and method with process control for stably forming images

A developing device is arranged such that Dg&#x3c;ds&#x3c;3Dg, and 3Dg&#x3c;dc&#x3c;6Dg, where ds is an end gap, Dg is an upstream gap, and dc is a center gap. The gap ds is a gap between a developer tankand either end portion of a developing rollerin the downstream of a transportation direction of the developing roller. The end portion of the developing rolleris an end portion thereof with respect to a rotation direction of the developing roller. The gap Dg is a gap between the developing rollerand a doctor blade. The gap dc is a smallest gap between the developer tankand the center portion b of the developing roller. With this arrangement, it is possible to prevent the toner scattering appropriately in the developing device for use of a two-component developer containing toner and carrier.

Developing device and image forming apparatus provided with same

An image apparatus includes a cartridge with two separate accommodating portions. The first accommodating portion for accommodating unused developer and is formed in a housing. A second accommodating portion for accommodating transfer residual developer is arranged adjacent to the first accommodating portion. A conveying member extending over the first and second accommodating portions, when an amount of transfer residual developer to be stored in the second accommodating portion exceeds a predetermined level, conveys the transfer residual developer from the second accommodating portion to the first accommodating portion. Each one of the accommodating portions includes an agitator.

Image apparatus with developing cartridge having two accommodating portions

A process cartridge includes a toner unit including a toner containing space and a toner supply space. A development unit including rollers. There is a holding frame having a fixture section for the development unit and an accepting section for the toner unit. The process cartridge is constructed arrangement in which the toner is fixed in a predetermined position in the accepting section of the holding frame or which the toner unit is detachably installed in a predetermined position in the accepting section of the holding frame.

Detachable process cartridge for image forming apparatus

A toner cartridge includes: a toner storage chamber; a toner collecting chamber; a partitioning wall for separating these chambers; a cylindrical return pipe penetrating through the partitioning wall with a conveyer screw arranged therein and is configured so that when the amount of untransferred toner collected into the toner collecting chamber exceeds the height of the return pipe, the untransferred toner is conveyed by the rotation of the conveyer screw to be returned into the toner storage chamber.

Toner cartridge and image forming apparatus

Toner cartridge

Developing unit for an image forming apparatus

The length of a conveying sheet is set to be greater than the rotational radius of an agitating element so that the distal end of the conveying sheet will slide over the inner wall of the toner container. A slider element having a low frictional resistance is attached at the distal end of the conveying sheet. The slider element preferably has a low coefficient of dynamic friction and is preferably made of a soft resilient material having a thickness smaller than the conveying sheet. Cutouts or openings may be preferably formed at the distal part. A multiple number of ribs are attached to the wall surface of the toner container at the highest position at which the wall and the top plate meet. The ribs are arranged apart from each other in the direction parallel to the agitating shaft of the agitating element. Each rib is a plate-like element projected inward from the wall surface in the toner container with its width put in the direction of the spacing. Further the end portions of the ribs on the interior side of the toner container are adapted to form a curved surface smoothly connecting the top plate surface and the wall surface.

Toner supply device with rotatable agitating element

A toner reserve container provided with a toner replenishing roller and a replenishing port which constitute a toner replenishing portion is arranged adjacent to a developing hopper and is provided with a toner conveying unit. The conveying unit includes an agitator rotated about a rotary shaft and a conveying sheet fixed to the agitator and scooping up and conveying toner to the toner replenishing roller. The conveying sheet has a plurality of slits formed close to the end portion where it is fixed to the agitator and extending in the direction from the end portion to the tip end of the conveying sheet. When the conveying sheet is rotated and deformed, the plurality of slits absorb rotational load to keep toner conveyed by the conveying sheet stable for a long period of time.

Developing unit with agitator and conveying sheet for toner

A developing unit includes a developing hopper, a toner reserve container that incorporates a replenishing roller and a replenishing port forming a toner replenishing portion, arranged adjacent to the developing hopper in order to supply the toner to the developing hopper. The toner reserve container further includes an agitator rotatable about a rotary shaft and a conveying sheet attached to the agitator for conveying the toner to the replenishing roller. The conveying sheet has a bent portion where the conveying sheet is bent in the rotational direction of the agitator at a halfway point thereof with a predetermined angle &agr;. Deformation of the conveying sheet during rotation is absorbed around the position of the bent portion, so that the conveying sheet will not be plastically deformed at the attached part of the conveying sheet joined to the attachment edge of the agitator, whereby long stable toner conveyance by the conveying sheet can be maintained.

Developing unit equipped with a toner replenishing device configured with a conveying sheet and rotator

A developing apparatus is equipped with a development casing, a development roller, and developer stirring shafts that rotate together with the development roller. In this developing apparatus, the developer stirring shafts are disposed adjacent to each other and are also disposed substantially in parallel with the development roller. Each developer stirring shaft has a rotational axis that rotates together with the development roller and has a plurality of stirring vanes of an approximately elliptic shape laid out at a predetermined angle with respect to the rotational axis. The rotational axis is provided substantially in parallel with the development roller. The stirring vanes are disposed substantially in parallel with each other, with the opposing stirring vanes between the adjacent developer stirring shafts having mutually different installation positions in the axial direction.

Developing apparatus having stirring shafts with elliptic stirring vanes

A developing unit includes a developer hopper, a toner reserve container that incorporates a replenishing roller and a replenishing opening forming a toner replenishing portion, arranged adjacent to the developer hopper in order to replenish the toner to the developer hopper. The toner reserve container further includes an agitator rotatable about a rotary shaft with a conveying sheet for conveying the toner to the replenishing roller. The conveying sheet is attached to the agitator so that it becomes close to the rotary shaft of the agitator. By this configuration, an adequate space can be secured between the top plate, i.e., an operable/closable lid, constituting the toner reserve container and the conveying sheet so that the distal part of the conveying sheet can efficiently retain the toner, thus making it possible to improve the conveyance performance to the replenishing roller and realize an uniform amount of conveyance.

Developing unit and toner replenishing device with conveying apparatus

A developer cartridge capable of being fitted to the toner replenishing opening of a developer storage hopper has a sealing member for sealing the toner therein that is bonded to the rim of its replenishing opening to be opposed to the opening of the developer storage hopper. The bottom face of this developer cartridge which constitutes the bottom for supporting the toner stored therein is inclined upwards in the stripping direction of the sealing member, whereby the supplied amount of the toner at the stripping start of the sealing member is regulated when the sealing member is stripped so that the toner can be uniformly supplied across the full length of the developer storage hopper with respect to the stripping direction of the sealing member.

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Hirakata, Japan

Tsutomu Nagata