Abstract: An image forming apparatus includes a charging unit that charges an image bearing member, a developing unit that forms a toner image on an latent image formed on the image bearing member, a transfer unit that transfers the toner image onto a transfer material, a charge neutralizer that neutralizes a charge of the image bearing member downstream of a transfer portion and upstream of a charging portion in a rotating direction of the image bearing member, a conductive collecting unit that collects a material adhering on the image bearing member downstream of the transfer portion and upstream of the charging portion, wherein the developing unit collects residual toner on the image bearing member, an voltage application unit sets a potential difference between the voltage applied to the collecting unit and the surface electric potential of the image bearing member not more than a discharge threshold.

Abstract: An image forming apparatus includes a charging unit that charges an image bearing member, a developing unit that forms a toner image on an latent image formed on the image bearing member, a transfer unit that transfers the toner image onto a transfer material, a charge neutralizer that neutralizes a charge of the image bearing member downstream of a transfer portion and upstream of a charging portion in a rotating direction of the image bearing member, a conductive collecting unit that collects a material adhering on the image bearing member downstream of the transfer portion and upstream of the charging portion, wherein the developing unit collects residual toner on the image bearing member, an voltage application unit sets a potential difference between the voltage applied to the collecting unit and the surface electric potential of the image bearing member not more than a discharge threshold.

Abstract: A control unit performs control to make a direction of an electric field generated in a first area of an image carrier forming a transfer portion during image forming operation, relative to a voltage applied to a brush member in a state where the first area passes through a contact portion, different from a direction of an electric field generated in a second area of the image carrier forming the contact portion, relative to the voltage applied to the brush member during a period when operation is shifted from first operation in which the image carrier is rotated at a first speed to second operation in which the image carrier is rotated at a second speed different from the first speed, during non-image forming operation different from the image forming operation.

Abstract: An image forming apparatus includes an image bearing member, a charging member, a development member, a transfer member, a charging voltage application unit, a development voltage application unit, and a control unit. The development member collects toner that remains on a surface of the image bearing member after a toner image is transferred from the image bearing member surface to transfer material. The control unit controls application of a development voltage to apply, to the development member in a cleaning operation, a development voltage having a polarity that is opposite to a normal polarity, and controls application of a charging voltage to apply, to the charging member, a charging voltage having the normal polarity such that a potential difference formed at a charging portion between the applied charging voltage and a surface potential formed at the image bearing member surface is lower than or equal to a discharge start voltage.

Abstract: A driving unit is controlled so that a driving state where an image bearing member is driven with a first potential difference formed between a brush member and the image bearing member at a contact portion where the image bearing member is in contact with the brush member transitions to a stopped state where the image bearing member stops being driven with a second potential difference formed, the second potential difference having an absolute value less than that of the first potential difference.

Abstract: An image forming apparatus includes a control unit configured to perform a first mode, a second mode, and a third mode. The first mode is a mode in which a sheet conveyance unit is controlled so that an arrival time from a passage of a trailing edge of a preceding sheet through a nip portion to an arrival of a leading edge of a succeeding sheet succeeding to the preceding sheet at the nip portion becomes a first time. The second mode is a mode in which the sheet conveyance unit is controlled so that the arrival time becomes a second time. The third mode is a mode in which the sheet conveyance unit is controlled so that the arrival time becomes a third time. The second time is longer than the first time, and the third time is longer than the second time.

Abstract: An image forming apparatus includes a charging unit that charges an image bearing member, a developing unit that forms a toner image on an latent image formed on the image bearing member, a transfer unit that transfers the toner image onto a transfer material, a charge neutralizer that neutralizes a charge of the image bearing member downstream of a transfer portion and upstream of a charging portion in a rotating direction of the image bearing member, a conductive collecting unit that collects a material adhering on the image bearing member downstream of the transfer portion and upstream of the charging portion, wherein the developing unit collects residual toner on the image bearing member, an voltage application unit sets a potential difference between the voltage applied to the collecting unit and the surface electric potential of the image bearing member not more than a discharge threshold.

Abstract: An image forming apparatus includes a photosensitive member, a charging member, electrostatic image forming portion, a developing member, a transfer member, a transfer voltage source, a brush member, a brush voltage source, and a controller capable of executing a cleaning operation. The controller carries out control so that the cleaning operation includes a first operation in which a potential difference is formed between the transfer member and the photosensitive member so that toner charged to a normal charge polarity is moved from the transfer member toward the photosensitive member, and a second operation in which a potential difference is formed between the brush member and the photosensitive member so that the toner charged to the normal charge polarity is moved from the photosensitive member toward the brush member.

Abstract: An image forming apparatus includes a control unit configured to perform a first mode, a second mode, and a third mode. The first mode is a mode in which a sheet conveyance unit is controlled so that an arrival time from a passage of a trailing edge of a preceding sheet through a nip portion to an arrival of a leading edge of a succeeding sheet succeeding to the preceding sheet at the nip portion becomes a first time. The second mode is a mode in which the sheet conveyance unit is controlled so that the arrival time becomes a second time. The third mode is a mode in which the sheet conveyance unit is controlled so that the arrival time becomes a third time. The second time is longer than the first time, and The third time is longer than the second time.

Abstract: A controller can select and execute a full color mode of performing image formation in a first state in which each primary transfer member is in contact with an intermediate transfer belt, and a monochrome mode of performing image formation in a second state in which only a primary transfer member is in contact with the intermediate transfer belt. The controller determines which state of the first state and the second state is formed, based on a detection result obtained by a current detection circuit when a photosensitive drum is charged by a charging roller, and voltage is applied to the primary transfer member from a primary transfer power source.

Abstract: An image forming apparatus includes: an image bearing member; a developer carrying member to correspond to the image bearing member; drive portion to rotationally drive the developer carrying member; control unit to control the rotational drive by the drive portion, and detection portion to detect information from the toner patch. Modes for controlling, by control unit, the rotational drive of the drive portion include (i) a first mode which uses a first driving condition including a first peripheral speed ratio between the developer carrying member and the image bearing member and (ii) a second mode which uses a second driving condition including a second peripheral speed ratio which is higher than the first peripheral speed ratio. The control unit controls the image bearing member to form the toner patch for each of peripheral speed ratios and sets the second driving condition on the basis of the detected information.

Abstract: A controller can select and execute a full color mode of performing image formation in a first state in which each primary transfer member is in contact with an intermediate transfer belt, and a monochrome mode of performing image formation in a second state in which only a primary transfer member is in contact with the intermediate transfer belt. The controller determines which state of the first state and the second state is formed, based on a detection result obtained by a current detection circuit when a photosensitive drum is charged by a charging roller, and voltage is applied to the primary transfer member from a primary transfer power source.

Abstract: An image forming apparatus includes: an image bearing member; a developer carrying member to correspond to the image bearing member; drive portion to rotationally drive the developer carrying member; control unit to control the rotational drive by the drive portion, and detection portion to detect information from the toner patch. Modes for controlling, by control unit, the rotational drive of the drive portion include (i) a first mode which uses a first driving condition including a first peripheral speed ratio between the developer carrying member and the image bearing member and (ii) a second mode which uses a second driving condition including a second peripheral speed ratio which is higher than the first peripheral speed ratio. The control unit controls the image bearing member to form the toner patch for each of peripheral speed ratios and sets the second driving condition on the basis of the detected information.

Abstract: An image forming apparatus includes a voltage adjustment portion having a voltage adjustment member connected to a contact member contacting an endless belt, the voltage adjustment portion changing a current flowing from a current supply member contacting the belt at a position different from a position, at which an image bearing member contacts the belt with respect to a rotating direction of the belt, to the voltage adjustment member via the belt according to a control signal input from a control portion outputting a control signal, thereby changing a size of a transfer potential to transfer a toner image borne by the image bearing member onto the belt at a part at which the belt contacts the image bearing member.

Abstract: The image forming apparatus includes an image bearing member; an ionically conductive intermediate transferring belt; a primary transfer member; an opposing member that opposes the current supply member through the intermediate transferring belt, and a control unit configured to execute a recovery operation in a state where a primary transfer in which a toner image is primarily transferred to the image intermediate transferring belt from the image bearing member is not performed, wherein the recovery operation includes to supply a current flowing in a flow direction opposite to a flow direction of a current in the primary transfer through the opposing member from the current supply member to remove an uneven distribution of the conductive agent in the intermediate transferring belt caused by primary transfer.

Abstract: A voltage applying portion applies voltage to a current supply member, the current supply member being provided with primary transfer voltage to pass current through a contact portion contacting with a belt, thereby bringing the potential of the belt a primary transfer potential, and being provided with secondary transfer voltage so that a potential difference for secondary transfer is formed between the current supplying member and a support member while a recording material is nipped by the contact portion. The voltage applying portion changes the second transfer voltage so that the potential difference for the secondary transfer between the current supply member and the support member becomes smaller as a potential adjusting portion that maintains the potential of the support member at a prescribed sustaining potential in a variable manner in order to change a primary transfer potential reduces gradually the sustaining potential.

Abstract: In a non-image forming state, an image forming apparatus changes the magnitude of a control signal output by a control portion, and when a current supply member supplies a belt with an amount of current generated by adding, to a predetermined target current used for image formation, an amount of current that flows from a contact member to the ground and changes in accordance with the magnitude of the control signal, the image forming apparatus acquires the magnitude of the control signal generated when the current, which is supplied from the current supply member to the belt and flows to a voltage adjusting member from the belt via the contact member, becomes zero.

Abstract: The present disclosure is directed to suppressing image defects due to variations in the values of currents flowing through respective photosensitive drums during image formation, and reducing the absolute value of a voltage applied when a primary transfer power supply unit applies a voltage of polarity opposite to that during image formation, to primary transfer members. There is provided an image forming apparatus including a transfer member configured to make contact with an inner peripheral surface of a transfer belt, a first power supply unit configured to apply a voltage to the transfer member, a resistance element connected between the first power supply unit and the transfer member, and a diode connected in parallel with the resistance element in a direction in which a current flowing in a first direction is blocked and a current flowing in a second direction is passed.

Abstract: After primary transfer, in a state where a pressing force of a primary transfer brush is released to separate an intermediate transfer belt from a photosensitive drum, current is impeded to the primary transfer brush. After that, the total current supplied from a secondary transfer roller and a conductive brush is set as a total current whose value is smaller than that of the total current supplied during the primary transfer.

Abstract: In a non-image forming state, an image forming apparatus changes the magnitude of a control signal output by a control portion, and when a current supply member supplies a belt with an amount of current generated by adding, to a predetermined target current used for image formation, an amount of current that flows from a contact member to the ground and changes in accordance with the magnitude of the control signal, the image forming apparatus acquires the magnitude of the control signal generated when the current, which is supplied from the current supply member to the belt and flows to a voltage adjusting member from the belt via the contact member, becomes zero.