Abstract: An aspect of the invention provides a charging control device of a color image forming apparatus, and the charging control device can properly control a charging potential of an image bearing body such that fog and uneven density are not generated even in a low-temperature environment. The image forming apparatus includes a high-voltage generation circuit 91 which applies an oscillating voltage to the charging member 42 disposed in contact with an image bearing body 41, a direct-current voltage and an alternating-current voltage being superimposed to form the oscillating voltage; a current detection unit 92 which detects a direct current value passed from the charging member 42 to the image bearing body 41; and a voltage control unit 96 which controls the alternating-current voltage such that the detected direct-current value is maintained in a target current range. The image forming apparatus also includes an aging control unit 95 to perform running-in.

Abstract: A controller takes in a detection signal indicating the surface electrical potential of a photoconductive drum (7) from a surface electrical potential sensor (step #1), and determines whether the surface electrical potential is smaller than the predetermined threshold value (step #2). As a result, when the controller (6) determines that the surface electrical potential is equal to or greater than the predetermined threshold value (NO in step #2), it uses the low print rate density patch to execute the density adjustments in accordance with the toner density and the developing bias associated with the density patch (step #3). When the controller (6) determines that the surface electrical potential is smaller than the predetermined threshold value (NO in step #1), it uses a high print rate density patch to execute the density adjustments in accordance with the toner density and the developing bias associated with the density patch (step #4).

Abstract: An image forming apparatus has a photosensitive drum (2), a transfer roller (5) above photosensitive drum (2), a transport line (14) that passes between photosensitive drum (2) and the transfer roller (5), a cleaning unit (6) below the transport line (14) and downstream of the photosensitive drum (2), and provided with a cleaning blade (11) and a polishing roller (10) to polish a surface of photosensitive drum (2), and rotation-direction selector (21) to selectively change a rotation direction of the polishing roller (10). The polishing roller (10) is above the cleaning blade (11) and rotationally upstream of photosensitive drum (2) relative to the cleaning blade (11). The rotation-direction selector (21) allows the polishing roller (10) to rotate in the same direction as the photosensitive drum (2) during a polishing mode for polishing the surface of photosensitive drum (2), and in a reverse direction at other times.

Abstract: An image forming apparatus is provided with a rotary image bearing member; a charging roller for charging the outer circumferential surface of the image bearing member by rotating in contact with the image bearing member; a brush roller for cleaning adhered matters on the outer circumferential surface of the charging roller by being held in contact with the charging roller due to its own weight and rotating; a driving mechanism for drivingly rotating the brush roller to have a linear velocity difference to the charging roller; and a moving mechanism for reciprocating the brush roller along the longitudinal direction thereof.

Abstract: An image forming apparatus charges the surface of a photosensitive member to a predetermined potential. A current detector detects a charging current when the charging bias is applied. A storage stores a target charging current value when the photosensitive member is charged to a required potential. A usage acquiring portion acquires information relating to usage of the charging roller. A bias corrector performs first and second corrections. The first correction compares a charging current value with a stored target charging current value and determines a new charging bias based on the comparison. The second correction determines whether usage of the charging roller is a predetermined first amount or a greater amount based on acquired usage information, and when the usage is the greater amount, changes the target charging current value in accordance with the usage amount and obtains a new charging bias based on the changed target charging current value.

Abstract: An image forming apparatus uses a charging roller to charge the surface of a photosensitive member to a predetermined potential. A current detector detects charging current when the charging bias is applied. A bias corrector corrects the charging bias and a storage stores a target charging current value when the photosensitive member is charged to a required potential. The bias corrector performs two corrections. The first correction compares a charging current value with a stored target charging current value, and determines a new bias based on the comparison. The second correction determines whether the bias obtained by the first correction is at a predetermined level or a higher level, and when the corrected charging bias is at the higher level, changes the target charging current value in accordance with the corrected charging bias and obtains a new charging bias on the basis of the changed target charging current value.

Abstract: An aspect of the invention provides a charging control device of a color image forming apparatus, and the charging control device can properly control a charging potential of an image bearing body such that fog and uneven density are not generated even in a low-temperature environment. The image forming apparatus includes a high-voltage generation circuit 91 which applies an oscillating voltage to the charging member 42 disposed in contact with an image bearing body 41, a direct-current voltage and an alternating-current voltage being superimposed to form the oscillating voltage; a current detection unit 92 which detects a direct current value passed from the charging member 42 to the image bearing body 41; and a voltage control unit 96 which controls the alternating-current voltage such that the detected direct-current value is maintained in a target current range. The image forming apparatus also includes an aging control unit 95 to perform running-in.

Abstract: A controller takes in a detection signal indicating the surface electrical potential of a photoconductive drum (7) from a surface electrical potential sensor (step #1), and determines whether the surface electrical potential is smaller than the predetermined threshold value (step #2). As a result, when the controller (6) determines that the surface electrical potential is equal to or greater than the predetermined threshold value (NO in step #2), it uses the low print rate density patch to execute the density adjustments in accordance with the toner density and the developing bias associated with the density patch (step #3). When the controller (6) determines that the surface electrical potential is smaller than the predetermined threshold value (NO in step #1), it uses the high print rate density patch to execute the density adjustments in accordance with the toner density and the developing bias associated with the density patch (step #4).

Abstract: An image forming apparatus has a photosensitive drum (2), a transfer roller (5) above photosensitive drum (2), a transport line (14) that passes between photosensitive drum (2) and the transfer roller (5), a cleaning unit (6) below the transport line (14) and downstream of the photosensitive drum (2), and provided with a cleaning blade (11) and a polishing roller (10) to polish a surface of photosensitive drum (2), and rotation-direction selector (21) to selectively change a rotation direction of the polishing roller (10). The polishing roller (10) is above the cleaning blade (11) and rotationally upstream of photosensitive drum (2) relative to the cleaning blade (11). The rotation-direction selector (21) allows the polishing roller (10) to rotate in the same direction as the photosensitive drum (2) during a polishing mode for polishing the surface of photosensitive drum (2), and in a reverse direction at other times.

Abstract: An image forming apparatus uses a charging roller to charge the surface of a photosensitive member to a predetermined potential. A current detector detects charging current when the charging bias is applied. A bias corrector corrects the charging bias and a storage stores a target charging current value when the photosensitive member is charged to a required potential. The bias corrector performs two corrections. The first correction compares a charging current value with a stored target charging current value, and determines a new bias based on the comparison. The second correction determines whether the bias obtained by the first correction is at a predetermined level or a higher level, and when the corrected charging bias is at the higher level, changes the target charging current value in accordance with the corrected charging bias and obtains a new charging bias on the basis of the changed target charging current value.

Abstract: An image forming apparatus charges the surface of a photosensitive member to a predetermined potential. A current detector detects a charging current when the charging bias is applied. A storage stores a target charging current value when the photosensitive member is charged to a required potential. A usage acquiring portion acquires information relating to usage of the charging roller. A bias corrector performs first and second corrections. The first correction compares a charging current value with a stored target charging current value and determines a new charging bias based on the comparison. The second correction determines whether usage of the charging roller is a predetermined first amount or a greater amount based on acquired usage information, and when the usage is the greater amount, changes the target charging current value in accordance with the usage amount and obtains a new charging bias based on the changed target charging current value.

Abstract: An image forming apparatus is provided with a rotary image bearing member; a charging roller for charging the outer circumferential surface of the image bearing member by rotating in contact with the image bearing member; a brush roller for cleaning adhered matters on the outer circumferential surface of the charging roller by being held in contact with the charging roller due to its own weight and rotating; a driving mechanism for drivingly rotating the brush roller to have a linear velocity difference to the charging roller; and a moving mechanism for reciprocating the brush roller along the longitudinal direction thereof.