Abstract: An image forming apparatus executes charging, exposure, toner-supply suspension, and electric-field generation while a photosensitive member rotates at least a full turn. In the charging, a charger charges a portion of a circumferential surface of the photosensitive member. In the exposure, an exposure device exposes the portion, which has been charged in the charging, of the circumferential surface. In the toner-supply suspension, before the portion, which has been exposed in the exposure, of the circumferential surface passes a position at which developer from a developing unit is configured to initially adhere to the circumferential surface, a developing unit stops supplying developer to the photosensitive member. In the electric-field generation, an electric field is generated in a portion of the photosensitive layer of the photosensitive member corresponding to the portion, which has been exposed in the second exposure, of the circumferential surface.

Abstract: A cleaning roller includes a shaft and an elastic body. The shaft extends in an axial direction where a center axis of the shaft extends. The shaft defines a radial direction and has a circumferential surface. The elastic body is helically wound about the shaft and defines a helical direction. The elastic body has a widthwise dimension in a widthwise direction orthogonal to the helical direction and to the radial direction. The elastic body has a base end portion extending in the helical direction and a distal end portion extending in the helical direction. The base end portion is in contact with the circumferential surface and fixed thereto. The distal end portion has a sharp edge and is positioned farthest from the circumferential surface in the radial direction. The widthwise dimension is gradually reduced from the base end portion to the distal end portion in the radial direction.

Abstract: A cleaning roller including a shaft including a rotational axis extending in an axial direction and an elastic layer covering the shaft. The elastic layer includes a base covering the shaft and a first helical protrusion protruding from the base and having a first helical ridge.

Abstract: An image forming apparatus includes a photosensitive member, a charger, a developing device, a transfer device, a scraper, and a controller. The controller performs an image formation process to form the developer image on the photosensitive member by using the developing device. The controller acquires, as a first value, at least one of a value of the charging current flowing in the charger and a value of the transferring current flowing in the transfer device. The controller calculates an accumulation current value by using result of an integral of a second value over time. The second value is an absolute value of the first value. The controller performs a scraping process in which the scraper scrapes the photosensitive member when the accumulation current value reaches a threshold value.

Abstract: In an image forming apparatus, the image bearing member has a surface and configured to rotate about an axis. The collection device is in contact with the surface, and configured to collect materials adhered to the surface. The developing roller is configured to provide a charged toner having a first polarity. The processor is configured to perform: executing a print job in a printing period; executing, in a non-printing period, a first process in which the image bearing member is rotated at least one rotation while a holding bias is applied to the collection device, the holding bias having a second polarity opposite to the first polarity; and executing, in a non-printing period after the first process, a second process in which the image bearing member is rotated while an ejection bias is applied to the collection device, the ejection bias having the first polarity.

Abstract: A cleaning roller comprises a shaft including a rotational axis extending in an axial direction and an elastic layer covering the shaft. The elastic layer includes a base covering the shaft and a first helical protrusion protruding from the base and having a first helical ridge.

Abstract: A cleaning roller includes a shaft and an elastic body. The shaft extends in an axial direction where a center axis of the shaft extends. The shaft defines a radial direction and has a circumferential surface. The elastic body is helically wound about the shaft and defines a helical direction. The elastic body has a widthwise dimension in a widthwise direction orthogonal to the helical direction and to the radial direction. The elastic body has a base end portion extending in the helical direction and a distal end portion extending in the helical direction. The base end portion is in contact with the circumferential surface and fixed thereto. The distal end portion has a sharp edge and is positioned farthest from the circumferential surface in the radial direction. The widthwise dimension is gradually reduced from the base end portion to the distal end portion in the radial direction.

Abstract: An image forming apparatus includes a photosensitive member, a charger, a developing device, a transfer device, a scraper, and a controller. The controller performs an image formation process to form the developer image on the photosensitive member by using the developing device. The controller acquires, as a first value, at least one of a value of the charging current flowing in the charger and a value of the transferring current flowing in the transfer device. The controller calculates an accumulation current value by using result of an integral of a second value over time. The second value is an absolute value of the first value. The controller performs a scraping process in which the scraper scrapes the photosensitive member when the accumulation current value reaches a threshold value.

Abstract: An image forming apparatus is provided with: an image forming unit having a photosensitive member, a charger, and a developer carrier, the image forming unit being configured to transfer the developer image to a recording sheet to form an image on the recording sheet; a motor configured to drive the photosensitive member and the developer carrier; a controller configured to control the motor and the charger, and a re-conveyance mechanism configured to reverse the recording sheet discharged from the image forming unit and to convey the recording sheet back towards the image forming unit. The controller is configured to turn off the charger after the motor is turned off, during a time period after the recording sheet is discharged from the image forming unit until the recording sheet is re-conveyed to the image forming unit by the re-conveyance mechanism.