An image forming unit including a photosensitive member including a gear portion on a one end side of the photosensitive member in a rotational axis direction, a roller that comes in contact with the photosensitive member, a bearing member that rotatably supports the roller, and an elastic member that urges the bearing member. In the image forming unit, directions of moments about a rotational axis of the roller acting on the bearing member disposed on the one end side of the photosensitive member in the rotational axis direction are the same in a case in which the roller is rotated and in a case in which the roller is stopped.

An image forming apparatus includes an intermediate transfer member that contacts an image bearing member to form a primary transfer portion, contacts a secondary transfer member to form a secondary transfer portion, and contacts a charging member that can receive a voltage from a charging power source, to form a charging portion. A toner image borne on the image bearing member is primarily transferred to the intermediate transfer member and secondarily transferred to a transfer material. If toner remains on the intermediate transfer member, the charging member electrically charges the remaining toner. If driving of the intermediate transfer member causes toner to drop onto the intermediate transfer member from the charging member, The timing at which to start image formation is controlled to prevent the dropped toner from moving to a transfer material conveyed to the secondary transfer portion.

A protruding portion protruding in a rotation axis direction of an image bearing member is provided at a position between the tip of a separation claw and an apex of the separation claw, when the apex of the separation claw is disposed at a position farthest from the surface of the image bearing member in a direction perpendicular to a straight line connecting the tip and the rotation center of a shaft portion of the separation claw.

A power supply apparatus includes: a detection circuit configured to feed back a voltage to a generation circuit. The detection circuit includes: a first resistor, a second resistor connected in series with the first resistor, a first conductive pattern configured to connect the first resistor and the second resistor in series, a first capacitor connected in parallel to the first resistor, a second capacitor connected in parallel to the second resistor and connected in series with the first capacitor, a second conductive pattern configured to connect the first capacitor and the second capacitor in series, and a third conductive pattern configured to electrically connect the first conductive pattern and the second conductive pattern. A thermal resistance of the third conductive pattern is greater than a thermal resistance of the first conductive pattern.

An image forming apparatus includes an intermediate transfer belt, an image forming device, a brush roller, a bias application device, and a controller. The bias application device applies, between the intermediate transfer belt and the brush roller, a bias for shifting a charged residual toner from the intermediate transfer belt to the brush roller. The controller controls, in a period in which calibration or maintenance is executed, the bias application device to set an application amount of the bias at a predefined first value only in a specified time zone in which the residual toner is present on the intermediate transfer belt and to set the application amount of the bias at a predefined second value smaller than the first value in time zones other than the specified time zone.

A photosensitive member unit includes a photosensitive member, a rotary member, a charging roller, a separating member, and a one-way clutch. The charging roller is moved to and positioned at the separate position in a case where the photosensitive member rotates in the second direction when the separating member is positioned at the first position. The charging roller is moved to and positioned at the contact position in a case where the photosensitive member rotates in the first direction when the separating member is positioned at the second position.

In a state that a first voltage is applied to a charging member so as to form a surface potential on a region of an image bearing member and a second voltage the same in polarity as the first voltage is applied to a transfer ember, a detection unit detects a transfer current in the region of the image bearing member during one rotation of the image hearing member after the region passes through a charging portion, when an absolute value of the surface potential formed on the region immediately before entry into the charging portion is larger than an absolute value of the surface potential formed on the region when it is positioned upstream of a transfer portion and downstream of the charging portion in a rotational direction of the image bearing member.

An electrophotographic image forming apparatus includes a photoconductive drum, a process roller to rotate in a state where the process roller elastically contacts a surface of the photoconductive drum, and a connecting member to allow the process roller to follow a movement of the photoconductive drum in an axial direction of the photoconductive drum.

An imaging device includes a photoconductive drum charged by a charge roll and opposed by developer roll. The developer roll adds toner to the drum to develop a latent image on the drum for transfer to media or an intermediate transfer member at a transfer roll. One or more high voltage power supplies communicate with a controller to set voltages on the rolls. During times of non-imaging, but rotation of the drum, the charge roll charges the drum to less than a Paschen breakdown voltage of the drum. A voltage of the transfer roll is determined that corresponds to a temperature and relative humidity of an operating environment of the imaging device and the developer roll is charged based thereon. The charge of the transfer roll is set close to the charge of the drum, but higher in magnitude. A laser may also discharge the drum.

An image forming apparatus includes an image carrier that carries an image to be transferred onto a recording medium, a charging member in contact with the image carrier, the charging member that charges the image carrier, an erase unit that erases charge on the image carrier; a current detector that detects a current flowing to the charging member; a forming unit that forms a charged region on a surface of the image carrier, and forms an erased region on the surface of the image carrier using the erase unit, and a state acquisition unit that acquires a deterioration state of the charging member based on (i) a first current flowing in response to applying a voltage from the charging member to the erased region and (ii) a second current flowing in response to applying a voltage from the charging member to the charged region.