Abstract: An image forming apparatus has a photosensitive member, a charger, a developing device, a transfer device, and a controller. In a printing control, the controller rotates the photosensitive member in a forward direction and applies a first transfer bias. In a reverse rotation control, the controller rotates the photosensitive member in a reverse direction and applies a second transfer bias being zero after finishing the printing control. In a forward rotation control, the controller rotates the photosensitive member in the forward direction and applies a third transfer bias for a period including a time that a part of the photosensitive member reaches the transfer device after finishing the reverse rotation control. The part faces the developing device when the rotating direction of the photosensitive member is switched. The third transfer bias has an opposite polarity to the first transfer bias and an absolute value larger than the second transfer bias.

Abstract: An image forming apparatus has a photosensitive member, a charger, a developing device, a transfer device, and a controller. In a printing control, the controller rotates the photosensitive member in a forward direction and applies a first transfer bias. In a reverse rotation control, the controller rotates the photosensitive member in a reverse direction and applies a second transfer bias being zero after finishing the printing control. In a forward rotation control, the controller rotates the photosensitive member in the forward direction and applies a third transfer bias for a period including a time that a part of the photosensitive member reaches the transfer device after finishing the reverse rotation control. The part faces the developing device when the rotating direction of the photosensitive member is switched. The third transfer bias has an opposite polarity to the first transfer bias and an absolute value larger than the second transfer bias.

Abstract: An image forming apparatus includes: a first image forming unit including a first transfer unit forming a first nip with a first photosensitive drum for black; a second image forming unit including a second transfer unit forming a second nip with a second photosensitive drum for a color; and a control device which, when a first sheet and a second sheet are continuously conveyed in corresponding order by the conveyance belt at the monochrome mode, is configured to supply a first transfer current for a first time period during which the first sheet or the second sheet pass through the second nip and supply a second transfer current, which is smaller than the first transfer current, for a second time period that is a sheet interval between the first sheet and the second sheet.

Abstract: An image forming device, comprising: a recovering member that is provided for the at least one photosensitive body and recovers adhered substances adhered to the at least one photosensitive body; a belt cleaner that removes the adhered substances adhered to the transfer belt; a cleaning process execution unit that executes a cleaning process in which the adhered substances are transferred from the recovering member to the transfer belt via the at least one photosensitive body; a use amount calculation unit that divides a developer image for transferring to the sheet-like medium into a plurality of areas in a main scanning direction so as to calculate a developer use amount in each of the plurality of areas; and a cleaning time determination unit that determines a time for which the cleaning process is executed, based on a maximum value of the developer use amounts of the plurality of areas.

Abstract: An image forming device, including: photosensitive bodies arranged in parallel in a predetermined direction; a belt that runs in the predetermined direction to transfer a developer image formed on each of the photosensitive bodies to a sheet-like medium; recovering members that are respectively provided for the photosensitive bodies, wherein each recovering member recovers adhered substances adhered to each photosensitive body after the developer image was transferred to the sheet-like medium; a belt cleaner that removes the adhered substances adhered to the belt; a cleaning process execution unit that executes a cleaning process in which the adhered substances are transferred from each recovering member to the belt via each photosensitive body; and a cleaning time determination unit that determines a time period for which the cleaning process is executed, based on a color of the image formed on the sheet-like medium.

Abstract: An image forming apparatus includes: a first image forming unit including a first transfer unit forming a first nip with a first photosensitive drum for black; a second image forming unit including a second transfer unit forming a second nip with a second photosensitive drum for a color; and a control device which, when a first sheet and a second sheet are continuously conveyed in corresponding order by the conveyance belt at the monochrome mode, is configured to supply a first transfer current for a first time period during which the first sheet or the second sheet pass through the second nip and supply a second transfer current, which is smaller than the first transfer current, for a second time period that is a sheet interval between the first sheet and the second sheet.

Abstract: An image forming device, including: photosensitive bodies arranged in parallel in a predetermined direction; a belt that runs in the predetermined direction to transfer a developer image formed on each of the photosensitive bodies to a sheet-like medium; recovering members that are respectively provided for the photosensitive bodies, wherein each recovering member recovers adhered substances adhered to each photosensitive body after the developer image was transferred to the sheet-like medium; a belt cleaner that removes the adhered substances adhered to the belt; a cleaning process execution unit that executes a cleaning process in which the adhered substances are transferred from each recovering member to the belt via each photosensitive body; and a cleaning time determination unit that determines a time period for which the cleaning process is executed, based on a color of the image formed on the sheet-like medium.

Abstract: An image forming device, comprising: a recovering member that is provided for the at least one photosensitive body and recovers adhered substances adhered to the at least one photosensitive body; a belt cleaner that removes the adhered substances adhered to the transfer belt; a cleaning process execution unit that executes a cleaning process in which the adhered substances are transferred from the recovering member to the transfer belt via the at least one photosensitive body; a use amount calculation unit that divides a developer image for transferring to the sheet-like medium into a plurality of areas in a main scanning direction so as to calculate a developer use amount in each of the plurality of areas; and a cleaning time determination unit that determines a time for which the cleaning process is executed, based on a maximum value of the developer use amounts of the plurality of areas.

Abstract: A belt cleaning device includes a cleaning roller, a backup roller, and a roller-pressing-state setting mechanism. The cleaning roller is disposed in confrontation with a surface of a belt. The backup roller is disposed in confrontation with the cleaning roller with the belt interposed between the cleaning roller and the backup roller. The roller-pressing-state setting mechanism selectively sets a state of the backup roller to a first state in which the backup roller is pressed against the cleaning roller via the belt, allowing a first pressure to be applied between the cleaning roller and the surface of the belt, and a second state in which a second pressure is applied between the cleaning roller and the surface of the belt. The second pressure is less than the first pressure.

Abstract: The present invention provides an image forming apparatus including a belt, a cleaning roller opposed to a surface of the belt, a voltage generating circuit generating a voltage applied to the cleaning roller, a voltage value detecting circuit detecting a voltage value applied to the cleaning roller, a control unit controlling the voltage generating circuit by inputting a control signal to the voltage generating circuit such that the voltage value detected by the voltage value detecting circuit is set to the same value as a target voltage value, and a target voltage value setting section setting the target voltage value based on a duty of the control signal input from the control unit to the voltage generating circuit.

Abstract: An image forming device is provided with a photoreceptor, a belt, a back member, a front member, and a voltage change device. The belt faces the photoreceptor. The back member is disposed on a back side of the belt. The front member is disposed on a front side of the belt. The front member is disposed adjacent to the belt and faces the back member. The voltage change device is configured to change voltage between the back member and the front member within a range excluding zero. Based on detected conditions such as the number of sheets printed, the replacement of a developer cartridge, or the current between the back member and the front member, the voltage change device change the voltage between the back member and the front member to enhance the ability to clean the belt.

Abstract: An image forming apparatus includes: a plurality of rollers including at least one drive roller to be rotatively driven; a belt passed around the plurality of rollers; and a press member which is disposed opposite the drive roller with the belt interposed therebetween and presses the belt against the drive roller.

Abstract: The present invention provides an image forming apparatus including a belt, a cleaning roller opposed to a surface of the belt, a voltage generating circuit generating a voltage applied to the cleaning roller, a voltage value detecting circuit detecting a voltage value applied to the cleaning roller, a control unit controlling the voltage generating circuit by inputting a control signal to the voltage generating circuit such that the voltage value detected by the voltage value detecting circuit is set to the same value as a target voltage value, and a target voltage value setting section setting the target voltage value based on a duty of the control signal input from the control unit to the voltage generating circuit.

Abstract: An image forming device is provided with a photoreceptor, a belt, a back member, a first front member, and a first voltage change device. The belt faces the photoreceptor. The back member is disposed on a back side of the belt. The first front member is disposed on a front side of the belt. The first front member is disposed adjacent to the belt and faces the back member. The first voltage change device is capable of changing voltage between the back member and the first front member within a range excluding zero.

Abstract: A belt cleaning device includes a cleaning roller, a backup roller, and a roller-pressing-state setting mechanism. The cleaning roller is disposed in confrontation with a surface of a belt. The backup roller is disposed in confrontation with the cleaning roller with the belt interposed between the cleaning roller and the backup roller. The roller-pressing-state setting mechanism selectively sets a state of the backup roller to a first state in which the backup roller is pressed against the cleaning roller via the belt, allowing a first pressure to be applied between the cleaning roller and the surface of the belt, and a second state in which a second pressure is applied between the cleaning roller and the surface of the belt. The second pressure is less than the first pressure.

Abstract: An image forming apparatus includes: a plurality of rollers including at least one drive roller to be rotatively driven; a belt passed around the plurality of rollers; and a press member which is disposed opposite the drive roller with the belt interposed therebetween and presses the belt against the drive roller.