Sharp Kabushiki Kaisha Corporation

Masatoshi Kaneshige

Masato Asanuma

Yasuyuki Ishiguro

Toshio Nishino

Yoshiaki Sanada

Naotaka Funayama

Tsutomu Nagata

Hiroshi Kubota

Jun Yamaguchi

Koichi Mihara

Hisashi Kunihiro

Toyoka Aimoto

Hiroshi Tanisawa

Yoshinori Otsuka

Hiroshige Araki

Haruko Yoneda

Takahiko Kimura

Toshihide Ohgoshi

Hideaki Hagihara

Hideaki Kurimoto

Toshihiko Takaya

Ryosuke Mano

Ikuo Itoh

Akira Nakakuma

Shuuhei Yamamoto

Tamio Yoshikai

Toshiyuki Kurosaka

Kohichi Mihara

A developing device of the present invention has a toner supply opening in a first carrying path and in the upstream of the developer carrying direction of a first carrying screw which is further from a developing roller; and a moquette member having feathers on its surface, and being provided, along the developer carrying direction, on the first carrying path. With this arrangement, it is possible to realize a compact developing device having a simple arrangement in which the supplied toner is speedily mixed with the preexisted developer, and the stable toner which is uniformly dispersed and charged can be speedily supplied for development.

Developing device and image forming apparatus including same

A toner bottle stores toner in a cylindrical section having an inner circumferential surface provided with a plurality of protruding portions raised inward the cylindrical section. When the cylindrical section is driven to rotate on its central axis, the toner is discharged from the cylindrical section via an outlet. When cross-sections perpendicular to the central axis of the cylindrical section are projected from a longitudinal direction of the cylindrical section, the cylindrical section has an inner circumference provided with one or more regions where the protruding portions are not projected. This prevents the toner from making contact with the protruding portions. Therefore, the toner can be conveyed while suppressing the generation of frictional heat by reducing the resistance between the toner and the protruding portions.

Developer container, developer supply device, and image forming apparatus

Toner cartridge

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

For realizing a satisfactory and stable developing process, the charge state of a developer and the density of toner particles contained in the developer is kept constant in the developing process. A developing roller to be driven rotationally is provided in a developing tank containing a developer. The developer is sucked magnetically using the magnetic force of a magnet provided in a developing sleeve composing the developing roller. The developer is then fed into a developing area opposed to a photosensitive member, then collected into the developing tank after the developing process is ended. The magnet is composed of an odd number of magnetic poles; developing pole, feeding pole, magnetic force distribution adjusting pole, developer sucking pole, developer separating pole, auxiliary collecting pole, and collecting pole. Between the sucking pole and the developing pole, an even number of poles are disposed. Between the developing pole and the separating pole are disposed an even number of poles. Consequently, the developer used for visualizing an image is separated while it is stuck on the developing sleeve when the developer is separated at the separating pole. When the developer is replaced, sticking of toner on the developing sleeve can be reduced significantly. In addition, the supplied developer is fixed in both toner density and charging level at the developing pole in developing.

Apparatus for controlling the movement of magnetized developer material

Disclosed is a method of determining the density of toner in the developer in an image forming apparatus by the use of a density sensor which is located beside a stirring member for stirring the developer. The density of toner is repeatedly measured at regular intervals for a predetermined period of time, which is the time required for the stirring member to make one complete revolution or a plurality of complete revolutions. The measured values of toner density are averaged, so that the mean value is taken as the density of toner in the developer. Since the values of toner density are averaged over the above-mentioned predetermined period of time, the unevenness in the toner density caused by the revolution of the stirring member is leveled off, thereby attaining accuracy in the determination of the toner density. Also because the density sensor is located beside the stirring member, the height of the developer tank can be kept small.

Method of determining the density of toner

The developing device, which is capable of mixing developers with magnetic toners and capable of providing the developers having a uniform magnetic toner density to a photoconductor for a copying machine, the device having a developing tank which contains a roller composed of a sleeve and a magnetic body with the magnetic body being disposed inside of the sleeve concentrically and rotatably with respect to each other, the device also having a magnetic toner supply tank disposed adjacent to the developing tank for supplying the magnetic toners to the developing tank through a toner supply port, the developing device includes a unit coupled to the developing tank for controlling an amount of the developers to be supplied to the sleeve, and a unit disposed between the toner supply port and the control unit for scraping the developers from the sleeve. The scraping unit is so arranged that a stirring portion is formed in association with the sleeve for stirring the developers scraped from the sleeve and the magnetic toners supplied from the toner supply tank through the toner supply port. The scaping unit has a throughhole for making the scraped developers to be mixed with the magnetic toners supplied from the toner supply tank through the toner supply port in accordance with a magnetic force produced by the magnetic body so as to produce a flow of the developers which passes through the throughhole.

Developing device with a scraping unit arranged to form a stirring area

A developing device for an electrophotographic copier includes a shutter along its toner supply route and a toner concentration detector sensor connected to a timing circuit. If the toner concentration is detected low, the timing circuit causes the toner supply to continue even after development is completed and the shutter is closed. An auxiliary stirrer is provided to keep stirring freshly supplied toner even after development is completed and the shutter is closed.

Developing device with shutter

A developing device for an electrophotographic apparatus includes a developing magnet roller, a transfer magnet roller and a separator for separating these rollers. Each of these rollers has a sleeve which is rotatably fitted around a columnar magnet piece. Between the sleeve of the developing magnet roller and the separator is a gap which is greater than the thickness of a developer layer formed on a surface of the sleeve of the developing magnet roller.

Developing device for electrophotographic apparatus having magnet rollers

A developing device for a copier is comprised of a developer roller having a shaft rotatably supported by its developing tank and a magnet structure affixed to this supporting shaft and having a plurality of magnet poles on its external peripheral surface. An arcuate brush forming plate is disposed between the developer roller and the photoreceptor of the copier. One end of this plate is formed to scrape developing agent attached to the developer roller such that it can be transported onto this brush forming plate.

Developing device with a magnetic brush turning plate

A developing device comprising: a developing magnet roller for feeding developer onto a photoreceptor; a shutter mechanism for switching from feeding developer to the developing magnet roller to suspending the above supply, or vice versa; a delivery magnet roller for receiving developer from the developing magnet roller and conveying it to a path leading to the shutter mechanism; a toner feed path for interconnecting a toner hopper disposed at the upper end of a main body of the developing device and the space above the shutter mechanism. In order to prevent toner from escaping through a gap formed between the toner hopper and its lid, the developing device is designed to have an interconnecting path for interconnecting the space in the vicinity of the toner feed path within the main body and a different space within the main body, or to have, within the toner hopper, a guide member for guiding air that has come into the toner hopper from the main body through the toner feed path, so as to avoid a gap between the toner hopper and its lid, thereby preventing toner from scattering outside the developing device through the above gap.

Developing device

A developing apparatus which includes a developing section disposed to confront a recording medium for effecting development, and a device for supplying developing material to the developing section. The developing device is characterized in that there is mounted a stirring device rotatably provided in a supply passage for supplying the developing material to the developing section, and shutter plates are provided on an outer periphery of the stirring device so as to be controlled for rotation, thereby selectively closing or opening the supply passage.

Developing apparatus

An image forming apparatus including a developing unit for developing an electrostatic latent image formed on an image carrier, and an image forming unit. A mechanism is provided which permits the image forming unit and developing unit to be mounted on or dismounted from the image forming apparatus in the proper order. A developing unit-positioning guide is provided by first mounting the image forming unit on the image forming apparatus.

Growing community of inventors

Ikoma, Japan

Masatoshi Kaneshige