Abstract: An image forming apparatus includes: a process unit cartridge including an IC chip memory configured to store a set value table in which a set value as the replacement life of a process unit cartridge and a present value as the number of times of reuse are stored; a reader writer configured to read data from and write data in the IC chip memory; and a control unit configured to compare the set value and the present value readout from the IC chip memory and cause, when the present value exceeds the set value, a display unit to display indication that replacement is necessary.

Abstract: The image forming apparatus has a communicating portion from the first chamber 24 to the second chamber 25, and a communicating portion from the first chamber 24 to the third chamber 26, which are separated from each other. With this structure, an active flow of fresh toner into the third chamber 26, where a developer having a low toner ratio and low toner concentration is stirred together with recycle toner during an image forming operation is suppressed.

Abstract: The image forming apparatus has a communicating portion from the first chamber 24 to the second chamber 25, and a communicating portion from the first chamber 24 to the third chamber 26, which are separated from each other. With this structure, an active flow of fresh toner into the third chamber 26, where a developer having a low toner ratio and low toner concentration is stirred together with recycle toner during an image forming operation is suppressed.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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-am

Abstract: 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.

Abstract: 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-am

Abstract: 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 replenishment 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.

Abstract: 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.

Abstract: 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.

Abstract: A test signal generating circuit generates internal test control signals from a small number of signals supplied via an address terminal in a test mode operation. According to the test control signals, the values of internal row address signal bits from an address buffer are set, while a row-related control circuit with test control function controls operations of a row selection circuit and bit line peripheral circuitry according to the test control signals. A plurality of word lines are driven simultaneously into a selected state and an acceleration test is performed according to a small number of control signals in a short period of time. Voltage stress applied between memory cell capacitors and between word lines can be accelerated with a small number of control signals.

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

Abstract: An image forming apparatus and method cause a connecting/conveying device to convey a recovered toner from a cleaner part to recovered toner housing means to house therein the recovered toner, and cause control means to control recovered toner supply means and new toner supply means in accordance with a toner concentration ratio in a developing device, which is detected by toner concentration ratio detecting means, to supply the recovered toner, which is stored in the recovered toner housing means, and a new toner, which is stored in new toner housing means, to the developing device.

Abstract: 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.

Abstract: 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 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.

Abstract: In an SDRAM chip, two signal generation circuits are provided corresponding to two test circuits arranged at either ends of a rectangular semiconductor substrate. Each signal generation circuit is provided in the proximity of corresponding test circuit. Hence, a signal line for test signal can be reduced and smaller chip area can be achieved compared with the conventional case where one signal generation circuit is provided at a center of the semiconductor substrate and a test signal is supplied to two test circuits from the signal generation circuit.