Sharp Kabushiki Kaisha Corporation

Masato Asanuma

Masatoshi Kaneshige

Syouichi Fujita

Hideji Saiko

Kouichi Takenouchi

Hisashi Kunihiro

Toyoka Aimoto

Hiroo Naoi

Itaru Kawabata

Hirofumi Sakita

Toshiaki Ino

Jitsuo Masuda

Toshihisa Ishida

Yasuo Kitabatake

Kouji Shinkawa

Yukihisa Imaue

Kanshiro Okamoto

Yasuyuki Ishiguro

Mitsuru Tokuyama

Hideaki Hagihara

Hiroshi Kawahito

Motoyuki Itoyama

Yoshiaki Sanada

Nobuhiko Nakano

Masayasu Narimatsu

Keiji Kato

Katsuaki Sumida

Yukinori Andou

Yasuo Imai

Eiji Sato

Yuichiro Takesue

Katsushi Inoue

Katsuzo Uchida

Naoyuki Yamane

Takashi Sugito

Miki Demoto

Tamio Yoshikai

Eisaku Hatanaka

Katuaki Sumida

Kyoichi Takada

Forced supply of toner(s) from toner hopper(s) to developer storage container(s) is executed while interrupting and/or prohibiting image forming operation(s) so as to prevent consumption of toner(s), toner level(s) within toner hopper(s) being determined to be low and low toner level condition(s) being reported to user(s) when temporal change(s) in value(s) detected by toner sensor(s) is/are small.

Toner level detection method and image forming apparatus employing such toner level detection method

A device has a process cartridge that includes a main cartridge accommodating a photosensitive body and a toner cartridge for use in replenis`hing toner as a precondition, is to precisely judge the service life of a photosensitive body and replacement timing of a main cartridge. Whether a predetermined condition is satisfied or not is judged with reference to a recording sheets count value G, a total operation time Tt and a toner cartridge related operation time Tx of the photosensitive drum, and a toner replenishing time Ts. In cases where a predetermined condition is satisfied, a message is displayed to urge the user to replace the process cartridge or the toner cartridge. When the toner is used up, the recording operation is inhibited, and an instruction to replace the process cartridge or the toner cartridge is displayed. Consequently, it is possible to accurately replace the photosensitive drum and toner cartridge at their respective adequate replacement timings.

Image forming apparatus with detachable mounting process cartridge

To solve problems that the amount of reuse toner increases with time recovery of reuse toner is efficiently achieved while forming an image of high quality. In a toner replenishing apparatus, toner recovered by a cleaning unit is conveyed via conveying device and contained in a recovery toner container. When an amount of the recovery toner exceeds a predetermined capacity of the recovery toner container, the recovery toner flows into a fresh toner container over an upper edge of a partition wall. Fresh toner and recovery toner are replenished to a developing unit via a fresh toner replenishing roller and a recovery toner replenishing roller, respectively, and the ratio between fresh toner and recovery toner is selected so that the fresh toner occupies a larger part than the recovery toner. This ratio is controlled on the basis of the cumulative rotation time of a photoconductor drum counted by a counting device.

Toner replenishing apparatus and image forming apparatus equipped with same

A cleaning device comprises: a first conveying member disposed further upstream in the rotating direction of a photoconductor drum than a cleaning blade, and constructed to rotate in non-contacting relationship to the photoconductor drum to convey residual toner that was removed by the cleaning blade; a second conveying member disposed parallel to the first conveying member and constructed to rotate in non-contacting relationship to the first conveying member; a first bias power supply for applying to the first conveying member a bias voltage having a polarity opposite to the proper polarity of the developer applied for development; and a second bias power supply for applying to the second conveying member a bias voltage having the same polarity as the proper polarity.

Cleaning device with electrically biased conveying members for

In an image forming apparatus having a developing unit for developing an image using toner, a toner box for withholding the toner, and a toner transportation section for transporting the toner withheld in the toner box to the developing unit, the toner transportation section includes a transportation screw portion having formed a spiral blade section on its shaft, a pipe section for controlling a toner transportation route by covering the transportation screw portion of the toner transportation section, and a toner flow suppressing section for suppressing flow of the toner from a space between the transportation screw and pipe section. Consequently, a toner transportation opening formed near the transportation section can be closed, and therefore, the flowing of toner into the developing unit can be controlled or reduced by a simple and inexpensive arrangement.

Image forming apparatus having developer supply device

An image forming apparatus has a developer container, a development device for developing a latent image formed on a surface of a photoreceptor drum by supplying toner to the latent image, and an agitation roller for supplying toner to the development device and agitating the toner in the developer container. The development device and the agitation roller are installed in the developer container. Moreover, the image forming apparatus includes a flying toner detecting device for detecting an amount of toner flying from the development device, and a control unit for controlling various developer operations such as the toner related agitating operation of the agitation roller, toner supply amount, etc. in response to a result of a detection performed by the flying toner detecting device. This structure prevents the toner from flying from the development device.

Image forming apparatus with flying toner detecting device

The present invention is intended to provide a compact development apparatus using a nonmagnetic one-component toner. The apparatus comprises a toner storage container, a toner supply roller, a toner passage through which supplied toner passes, and an attracting fan for attracting the toner and generating a toner powder stream. The toner is held in the toner storage container. The toner supply roller supplies the toner from a supply port of the storage container. The toner passage is provided with an opening opposite to a photosensitive drum. The toner supplied into the toner passage and frictionally charged is attracted by the attracting fan. The toner travels from the opening to the drum. The toner adheres to an electrostatic latent image on the drum and thus the image is developed. Unused toner is transported into the toner passage and recovered.

Development apparatus for developing electrostatic latent image held by

The image forming apparatus of the invention controls the toner density by any one of the following configurations: by correcting the toner density of the developer in association with the agitation total; by controlling a process parameter so that the density of a toner patch formed on the photoreceptor corresponds to a prescribed density value and determining that developing performance of the developer is improved and canceling the toner density correction when the process parameter reaches the prescribed value; by changing the toner density reference value when the variation as to the charger output is equal to or greater than a first predetermined value and maintaining the changed toner density reference value until the variation of the charger output again becomes equal to or greater than the first predetermined value; or by prohibiting toner supply for a constant duration to prevent excessive toner supply if time from the end of the last operation of the developing unit to the start of a next operation, inclusive of the power-activation is equal to or longer the a predetermined period when the developing unit is activated to commence agitation of the developer.

Toner density control for an image forming apparatus

A developing unit comprises a magnet roller, a stirring roller, a carrying screw, a toner density sensor, and a sensor level adjusting device. When feeding or exhausting the developing powder, the rollers and screw are driven at a slower or faster rotary speed than the speed given when developing an image. After the supply of the developing powder is terminated, the rotary speed of the rollers and the screw is changed to the speed given for developing an image. After a certain time is elapsed, the adjusting device serves to start the level adjustment when the sensor produces a stable output.

Developing unit having capability of efficiently exchanging developing

A toner hopper is arranged to feed the toner stored in itself to a developing unit and have a stirring roller and a feeding roller respectively supported rotatably, an interlocking mechanism for transmitting the force of rotation to the stirring roller, a manually rotating mechanism for manually rotating the stirring roller, and an interlocking restricting mechanism. The interlocking mechanism restricts the operation of the interlocking mechanism such that the force of rotation of the stirring roller is not transmitted to the feeding roller while the manually rotating mechanism supplies force of rotation to the stirring roller.

Toner hopper having stirring and feeding rollers

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

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 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.

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Nara, Japan

Masato Asanuma