Abstract: A power supply device includes: a DC power supply that generates a DC voltage of a variable value and outputs the DC voltage; an AC power supply that generates an AC voltage of a variable value, and superimposes the AC voltage and the DC voltage to generate a superimposed voltage for output; and a control circuit. The control circuit start giving the DC power supply an instruction to output the DC voltage, and start giving the AC power supply an instruction to output the AC voltage for restricting output of the DC voltage. The control circuit controls an absolute value of the superimposed voltage to be smaller than or equal to a predetermined value in a predetermined period from a time when the giving of the instruction to output the AC voltage is started to a time when the restricting of the output of the DC voltage is started.

Abstract: An image forming system includes a post-processing unit capable of performing a post-processing on the sheet on which the toner image is formed. The image forming system is capable of executing a transfer cleaning operation to more toner from a transfer member to an image bearer by electrostatic force caused by cleaning bias applied by a bias applying unit in a state where the image bearer and the transfer member are rotated, to clean the transfer member, as an inter-sheet operation performed when at least one of inter-sheet areas that exist on the image bearer during a successive image forming period. The image forming system is capable of executing a rotation stop operation to stop rotation of the image bearer and the transfer member, as the inter-sheet operation when the post-processing is performed, in addition to the transfer cleaning operation, before or after the transfer cleaning operation is executed.

Abstract: An image forming apparatus includes an image bearer, a charging, a charge power supply to supply a charging bias to the charging device, a developing device, a toner adhesion amount detector, an environment detector, and a controller to determine whether to execute a charging bias adjustment process in which the charging device charges the image bearer to have different potentials, the developing device supplies the toner to the image bearer according to the different potentials, the toner adhesion amount detector detects the amount of toner adhering to the image bearer, and the controller adjusts the charging. The controller includes a memory device to store the environment data, and is configured to compare the environment data with previous environment data stored in the memory device, and determine not to execute the charging bias adjustment process when an environment change amount is not greater than a threshold.

Abstract: An image forming apparatus includes an image bearer, a charging, a charge power supply to supply a charging bias to the charging device, a developing device, a toner adhesion amount detector, an environment detector, and a controller to determine whether to execute a charging bias adjustment process in which the charging device charges the image bearer to have different potentials, the developing device supplies the toner to the image bearer according to the different potentials, the toner adhesion amount detector detects the amount of toner adhering to the image bearer, and the controller adjusts the charging. The controller includes a memory device to store the environment data, and is configured to compare the environment data with previous environment data stored in the memory device, and determine not to execute the charging bias adjustment process when an environment change amount is not greater than a threshold.

Abstract: An image forming system includes a post-processing unit capable of performing a post-processing on the sheet on which the toner image is formed. The image forming system is capable of executing a transfer cleaning operation to more toner from a transfer member to an image bearer by electrostatic force caused by cleaning bias applied by a bias applying unit in a state where the image bearer and the transfer member are rotated, to clean the transfer member, as an inter-sheet operation performed when at least one of inter-sheet areas that exist on the image bearer during a successive image forming period. The image forming system is capable of executing a rotation stop operation to stop rotation of the image bearer and the transfer member, as the inter-sheet operation when the post-processing is performed, in addition to the transfer cleaning operation, before or after the transfer cleaning operation is executed.

Abstract: An image forming system includes a post-processing unit capable of performing a post-processing on the sheet on which the toner image is formed. The image forming system is capable of executing a transfer cleaning operation to move toner from a transfer member to an image bearer by electrostatic force caused by cleaning bias applied by a bias applying unit in a state where the image bearer and the transfer member are rotated, to clean the transfer member, as an inter-sheet operation performed when at least one of inter-sheet areas that exist on the image bearer during a successive image forming period. The image forming system is capable of executing a rotation stop operation to stop rotation of the image bearer and the transfer member, as the inter-sheet operation when the post-processing is performed, in addition to the transfer cleaning operation, before or after the transfer cleaning operation is executed.

Abstract: An image forming apparatus includes an electrostatic latent image bearer; a charger to charge a surface of the electrostatic latent image bearer; a power source to output a charging bias supplied to the charger; an electrostatic latent image writing unit to write an electrostatic latent image on the surface of the electrostatic latent image bearer charged by the charger; a developing unit including a developing member to develop the electrostatic latent image to obtain a toner image; a developing power source to output a developing bias supplied to the developing unit; a processor to adjust the charging bias output from the power source to a predetermined target value; and a storage unit to store an adjustment value algorithm.

Abstract: An image forming apparatus is provided in which, during a continuous sheet passing, in the case where a between-sheets time is short, none of a cleaning mode and a drive OFF mode is performed; in the case where the between-sheets time is of a medium length of time, the cleaning mode is performed but the drive OFF mode is not performed; and in the case where the between-sheets time is long, both the cleaning mode and the drive OFF mode are performed. As a result, degradation of an image bearer due to the cleaning bias is alleviated, decreased productivity due to the cleaning mode is alleviated, a problem is alleviated in which a back surface of a recording medium gets dirty due to toner adhered to a transfer rotation body, and another problem is alleviated in which the service life of a driven member is shortened.

Abstract: An image forming apparatus includes an image bearer; a developing device; a transfer device; a waste-developer container; a developer collecting device including a collected-developer conveyor, a waste channel, a reuse channel, and a channel switching member to switch a route between the waste channel and the reuse channel; a switching determiner to determine whether to dispose or reuse collected developer; an operating condition data collector to collect and store operating condition data used as a degradation speed index of developer in the developing device; a determination type selector to select, according to the degradation speed index, one of a first determination type based on an operating amount and a second determination type based on developer replacement data indicating an amount of developer replaced with supplied developer in the developing device; and a switching controller to control the channel switching member according to determination made by the switching determiner.

Abstract: An image forming apparatus includes an image bearer rotating in a first direction while bearing a toner image thereon in a normal image forming operation; a toner image forming device to form the toner image on the image bearer; a transferring device to transfer the toner image to a recording medium eventually; a cleaning blade to block toner remaining on image bearer without being transferred; and a controller. The controller controls the image bearer to perform an inverse rotation operation in which the image bearer rotates in a second direction opposite to the first direction after controlling the toner image forming device to perform a special image forming operation such that the amount of toner input to the cleaning blade in the special image forming operation is greater than the amount of toner input to the cleaning blade in the normal image forming operation, and then stopping the image bearer.

Abstract: An image forming system includes a post-processing unit capable of performing a post-processing on the sheet on which the toner image is formed. The image forming system is capable of executing a transfer cleaning operation to move toner from a transfer member to an image bearer by electrostatic force caused by cleaning bias applied by a bias applying unit in a state where the image bearer and the transfer member are rotated, to clean the transfer member, as an inter-sheet operation performed when at least one of inter-sheet areas that exist on the image bearer during a successive image forming period. The image forming system is capable of executing a rotation stop operation to stop rotation of the image bearer and the transfer member, as the inter-sheet operation when the post-processing is performed, in addition to the transfer cleaning operation, before or after the transfer cleaning operation is executed.

Abstract: A development device is operable in multiple different speed modes and includes a developer bearer to carry developer, a developer regulator to adjust an amount of developer carried on the developer bearer, and multiple developer conveyance members disposed facing the developer bearer to transport developer in a longitudinal direction to circulate developer inside the development device. The multiple developer conveyance members including a first developer conveyance member to supply developer to the developer bearer and a second developer conveyance member to transport developer collected from the developer bearer. The development device executes developer amount balance adjustment in which a driving velocity of at least the multiple developer conveyance members is increased from a driving velocity in a lower-speed mode for a predetermined period after image development in the lower speed mode is completed and before image development in a higher speed mode is started.

Abstract: An image forming apparatus includes a latent image bearing member, a charging unit, a charging power source, a latent image writing unit, a development unit, a transfer unit, a toner detector, and a controller. The controller causes a background fog pattern to be formed on a surface of the latent image bearing member. In addition to the background fog pattern, the controller causes a latent image to be developed to form a toner image used for position identification on the surface of the latent image bearing member. The controller identifies a time when the toner image used for position identification has entered a detection range of the toner detector based on a change in outputs of the toner detector to determine a time when each of sections of the background fog pattern enters the detection range based on the identified time.

Abstract: An image forming apparatus is provided in which, during a continuous sheet passing, in the case where a between-sheets time is short, none of a cleaning mode and a drive OFF mode is performed; in the case where the between-sheets time is of a medium length of time, the cleaning mode is performed but the drive OFF mode is not performed; and in the case where the between-sheets time is long, both the cleaning mode and the drive OFF mode are performed. As a result, degradation of an image bearer due to the cleaning bias is alleviated, decreased productivity due to the cleaning mode is alleviated, a problem is alleviated in which a back surface of a recording medium gets dirty due to toner adhered to a transfer rotation body, and another problem is alleviated in which the service life of a driven member is shortened.

Abstract: An image forming apparatus includes an image bearer; a developing device; a transfer device; a waste-developer container; a developer collecting device including a collected-developer conveyor, a waste channel, a reuse channel, and a channel switching member to switch a route between the waste channel and the reuse channel; a switching determiner to determine whether to dispose or reuse collected developer; an operating condition data collector to collect and store operating condition data used as a degradation speed index of developer in the developing device; a determination type selector to select, according to the degradation speed index, one of a first determination type based on an operating amount and a second determination type based on developer replacement data indicating an amount of developer replaced with supplied developer in the developing device; and a switching controller to control the channel switching member according to determination made by the switching determiner.

Abstract: A development device is operable in multiple different speed modes and includes a developer bearer to carry developer, a developer regulator to adjust an amount of developer carried on the developer bearer, and multiple developer conveyance members disposed facing the developer bearer to transport developer in a longitudinal direction to circulate developer inside the development device. The multiple developer conveyance members including a first developer conveyance member to supply developer to the developer bearer and a second developer conveyance member to transport developer collected from the developer bearer. The development device executes developer amount balance adjustment in which a driving velocity of at least the multiple developer conveyance members is increased from a driving velocity in a lower-speed mode for a predetermined period after image development in the lower speed mode is completed and before image development in a higher speed mode is started.

Abstract: An image forming apparatus includes a latent image carrier, a charging device, a latent image forming device, a developing device, a transfer device, a toner amount detector, and a control circuit to execute an imaging condition determination process. The control circuit obtains a linear approximation formula of a developing potential and an amount of toner according to an exposure potential of the patch pattern and a detected amount of toner to calculate a developing gamma and a developing start voltage according to a gradient of the linear approximation formula, determines target charging potential, exposure potential and developing bias according to the developing gamma and the developing start voltage, determines an amount of a background potential to be corrected according to a difference between the developing start voltage and a target developing start voltage obtained according to environmental information, and corrects the target charging potential.

Abstract: The image forming apparatus includes a process unit, a latent image writer, a power source, and a controller. The process unit is detachably attachable relative to the image forming apparatus and includes, as a single integrated unit, a latent image bearing member to bear a latent image on a surface thereof, a charging device to charge the surface of the latent image bearing member, and a development device to develop the latent image with toner. The controller causes the power source to output a charging bias at a predetermined target level supplied to the charging device. The process unit includes a first storage device to store correction information for calculating the predetermined target level of the charging bias in accordance with a combination of the latent image bearing member and the charging device. The controller corrects the predetermined target level based on the correction information in the first storage device.

Abstract: An image forming apparatus includes an image bearer rotating in a first direction while bearing a toner image thereon in a normal image forming operation; a toner image forming device to form the toner image on the image bearer; a transferring device to transfer the toner image to a recording medium eventually; a cleaning blade to block toner remaining on image bearer without being transferred; and a controller. The controller controls the image bearer to perform an inverse rotation operation in which the image bearer rotates in a second direction opposite to the first direction after controlling the toner image forming device to perform a special image forming operation such that the amount of toner input to the cleaning blade in the special image forming operation is greater than the amount of toner input to the cleaning blade in the normal image forming operation, and then stopping the image bearer.

Abstract: An image forming apparatus includes a latent image carrier to carry a latent image on a surface thereof, a developing device to develop the latent image with toner to form a toner image on the surface of the latent image carrier, a transfer unit to transfer the toner image onto a recording medium, and a controller. The controller executes an image density adjustment control of adjusting a developing bias to obtain a target image density. The controller further executes a forced toner consumption control of forcibly consuming the toner contained in the developing device by attaching the toner to the latent image carrier to form a toner pattern on the surface of the latent image carrier. The controller executes the forced toner consumption control to forcibly consume a smaller amount of toner in response to a higher developing bias as adjusted by the image density adjustment control.