Other

Kabushiki Kaisha Toshiba

Toshiba Tec Kabushiki Kaisha

Tetsuo Katoh

Shinichi Itoh

Tatsuyuki Miura

Seiji Tsuzuki

Takafumi Amano

Koichi Kuroyama

The image forming apparatus has a communicating portion from the first chamberto the second chamberand a communicating portion from the first chamberto the third chamberwhich are separated from each other. With this structure, an active flow of fresh toner into the third chamberwhere a developer having a low toner ratio and low toner concentration is stirred together with recycle toner during an image forming operation is suppressed.

Image forming apparatus and toner stirring method

In an image forming apparatus employing a two-component developing system, there are provided printed-sheet number counting means; developing-device drive time integrating means for integrating time during which a developing device drives; and a toner replenishing motor drive time integrating means for integrating time during which a toner replenishing motor drives. Integrated drive time of the developing device and integrated drive time of the toner replenishing motor every fixed printed-sheet number, and the toner consuming quantity per drive time of the developing device is calculated from the extracted data. The toner charge quantity in a developer is predicted on the basis of the calculated data, and a developing bias voltage applied to the developing device is changed to thereby revise an image density.

Image forming apparatus and method for revising image density

After a toner empty state, toner is filled. Following the filling of toner, a forcible toner replenishment mode is performed. After release of the forcible toner replenishment mode, a printer CPU replenishes only fresh toner and does not replenish recycled toner while image formation is performed on a predetermined number of paper sheets or while a developing device is driven for a predetermined time.

Image forming apparatus and developer replenishment control method

In an image forming apparatus employing a two-component developing system, there are provided print-sheet number counting means; developing-device drive time integrating means for integrating time during which a developing device drives; and a toner replenishing motor drive time integrated drive time integrating means for integrating time during which a toner replenishing motor drives. Integrated drive time of the developing device and integrated drive time of the motor toner replenishing motor every fixed printed-sheet number, and the toner consuming quantity per drive time of the developing device is calculated from the extracted data. The toner charge quantity in a developer is predicted on the basis of the calculated data, and a developing bias voltage applied to the developing device is changed to thereby revised an image density.

An apparatus for controlling the supply of a developing agent, installed in a developer, is equipped with a developing-agent amount detector to detect an amount of the developing agent consumed by the developer; a driving-time detector to detect a driving time for actually shaking the developing agent provided in the developer; a developing-agent density calculator to calculate an actual density of the developing agent in the developer based on the consumed amount of the developing agent detected by the developing-agent amount detector and the actual driving time detected by the driving-time detector; a developing-agent amount controller to compare the actual density detected by the developing-agent density calculator and a reference developing-agent density to perform forcible supply of the developing agent when the actual density is lower than the reference density whereas forcible consumption of the developing agent when the actual density is equal to or higher than the reference density; and a consumed-amount adjuster to adjust the consumed amount of the developing agent per unit of time under control by the developing-agent amount controller.

Apparatus and method of controlling supply of developing agent to developer

A fixing device is disclosed which includes a heat roller and a press roller through which an image recording medium carrying thereon a toner image is passed for fixing the toner image to the image recording medium. The fixing device further includes a sheet supply shaft carrying thereon a roll of cleaning sheet in the form of a web, a sheet winding shaft for winding thereon the cleaning sheet, and a motor for controllably driving the sheet winding shaft, the cleaning sheet being pressed against the heat roller for cleaning the peripheral surface thereof while being wound on the sheet winding shaft. The cleaning sheet is provided on one surface thereof with a pattern of markings, such as graduations, which is detectable by an optical sensor. The current speed of movement of the cleaning sheet is calculated by a speed calculator based on detection signals from the optical sensor. A speed of rotation of the motor is controlled so that the current sheet speed becomes a predetermined target speed.

Image forming apparatus including a cleaning sheet for cleaning a peripheral surface of a heat roller

An image forming apparatus and method causes a connecting/conveying device to convey a recovered toner from a cleaner part to a recovered toner housing unit to house therein the recovered toner. A controller controls a recovered toner supply unit and new toner supply unit in accordance with a toner concentration ratio in a developing device, which is detected by toner concentration ratio detecting unit, to supply the recovered toner, which is stored in the recovered toner housing unit, and a new toner, which is stored in new toner housing unit, to the developing device. The controller causes the amount of the recovered toner to be supplied to be less than the amount of the recovered toner during a usual operation, which is determined in accordance with the contents detected by the toner concentration ratio detecting unit, or stops the supply of the recovered toner, while a predetermined period condition is satisfied after the occurrence of a predetermined event in which the amount of the recovered toner stored in the recovered toner housing unit is temporarily excessive.

Apparatus and method for controlling the formation of an image with recovered and new toner

An image forming apparatus and method cause a connecting/conveying device to convey a recovered toner from a cleaner part to a recovered toner housing to house therein the recovered toner, and cause a control device to separately control a recovered toner supply device and a new toner supply device to supply the recovered toner, which is stored in the recovered toner housing, and/or a new toner, which is stored in a new toner housing, to a developing device. The control device restricts the supply of the recovered toner from the recovered toner housing to the developing device when a no-residual-amount detecting device detects no residual amount of the new toner in the new toner housing.

Apparatus and method for supplying new and recovered toner to a developing device

An image forming apparatus and method cause a connecting/conveying device to convey a recovered toner from a cleaner part to a recovered toner housing to house therein the recovered toner, and cause a controller to control a recovered toner supply and a new toner supply in accordance with a toner concentration ratio in a developing device, which is detected by a toner concentration ratio detector, to supply the recovered toner, which is stored in the recovered toner housing, and the new toner, which is stored in the new toner housing, to the developing device. The controller separately controls the recovered toner supply and the new toner supply in accordance with the contents detected by the toner concentration ratio detecting means, to cause to change the combination of the amounts of the recovered toner and new toner to be supplied to the developing device.

Apparatus and method for forming image

A developing apparatus faces an image carrier carrying an electrostatic latent image and comprises a developing section for developing the electrostatic latent image by supplying a developing agent thereto and a feeding section for feeding the developing agent to the developing section while stirring. The feeding section has a rotatable shaft member, a blade body formed spirally on an outer peripheral surface of the shaft member for feeding the developing agent in a shaft direction, and a plurality of projections located between tilted blade portions on the outer peripheral surface of the shaft member. The projections, each being placed at an interval from the tilted blade portions of the blade body and are arranged at predetermined intervals along circumference of the shaft member.

Developing apparatus and image forming apparatus

A toner density sensor detects the state where a toner cartridge is empty and the toner density in a developing unit is therefore low. In accordance with the sensing output of the toner density sensor, the surface potential of a photosensitive drum is decreased. By this control, the carriers of the developing agent are prevented from being attracted onto the photosensitive drum during the period between the time when the toner cartridge becomes empty and the toner density begins to decrease and the time when the copying operation stops due to the toner empty state. Hence, the images formed during that period are not poor in quality.

Image forming apparatus capable of varying charge amount in accordance

An image forming-apparatus of the present invention includes a charging device for applying a first potential and a second potential to a photosensitive drum, a keyboard for inputting a magnification of a copy image to be formed on the photosensitive drum, and a controller for controlling the charging device to control the magnitude of the potentials applied to the photosensitive drum from the charging device in accordance with the magnification input by the keyboard, thus increasing a difference between the first and second potentials in accordance with the degree of variation of the magnification in the case where the magnification input by the keyboard is less than 1.00.

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Kunitachi, Japan

Tetsuo Katoh