Abstract: An image forming apparatus includes a rotatable intermediate transfer member; a first image forming portion having a first photosensitive member which rotates, a first developing unit, and a first charge eliminating unit; a second image forming portion that is located on a downstream side of the first image forming portion in a rotational direction of the intermediate transfer member, and that has a second photosensitive member which rotates, a second developing unit, and a second charge eliminating unit; a transfer unit; and a switching unit that switches a light amount of the second charge eliminating unit when a usage amount of the second image forming portion reaches a predetermined amount to a value that is greater than a light amount of the first charge eliminating unit when a usage amount of the first image forming portion reaches the predetermined amount.

Abstract: An image forming apparatus includes a photosensitive member, a first charging roller, a first cleaning member, a second charging roller, and a second cleaning member. The following relationship is satisfied: (X×L0+L1+L2)?(Y×L3+L4)?0 where L0 represents a length of a whole circumference of the first charging roller, L1 represents a length between a first contact area and a first contact position of the first charging roller and the photosensitive member, L3 represents a length of a whole circumference of the second charging roller, L4 represents a length between a second contact area and a second contact position, L2 represents a length between the first contact position and the second contact position, X represents an integer in a range of 0?X?40, and Y represents an integer in a range of 0?Y?40.

Abstract: An image forming apparatus has a changing portion configured to change, based on a detection result of a temperature sensor, response sensitivity in starting of power supply by a determination portion based on a detection result of a human body detection sensor in a case where a human body approaches the human body detection sensor. The changing portion increases the sensitivity in a case where a temperature detected by the temperature sensor is a second temperature lower than a first temperature than in a case where the temperature detected by the temperature sensor is the first temperature.

Abstract: An image forming apparatus includes a photosensitive member, a first charging roller, a first cleaning member, a second charging roller, and a second cleaning member. The relationship is satisfied (X×L0+L1+L2)?(Y×L3+L4)?0 where L0 represents a length of a whole circumference of the first charging roller, L1 represents a length between the first contact area and the first contact position of the first charging roller and the photosensitive member, L3 represents a length of a whole circumference of the second charging roller, L4 represents a length between the second contact area and the second contact position, L2 represents a length between the first contact position and the second contact position, X represents an integer in a range of 0?X?40, and Y represents an integer in a range of 0?Y?40.

Abstract: An image forming apparatus includes: a rotatable intermediate transfer member; a first image forming portion having a first photosensitive member which rotates, a first developing unit, and a first charge eliminating unit; a second image forming portion that is located on a downstream side relative to the first image forming portion in a rotational direction of the intermediate transfer member, and that has a second photosensitive member which rotates, a second developing unit, and a second charge eliminating unit; a transfer unit; and a switching unit that switches a light amount of the second charge eliminating unit when a usage amount of the second image forming portion reaches a predetermined amount to a value that is greater than a light amount of the first charge eliminating unit when a usage amount of the first image forming portion reaches the predetermined amount.

Abstract: An image forming apparatus has a changing portion configured to change, based on a detection result of a temperature sensor, response sensitivity in starting of power supply by a determination portion based on a detection result of a human body detection sensor in a case where a human body approaches the human body detection sensor. The changing portion increases the sensitivity in a case where a temperature detected by the temperature sensor is a second temperature lower than a first temperature than in a case where the temperature detected by the temperature sensor is the first temperature.

Abstract: An image forming apparatus includes an intermediary transfer member, a first image forming portion including a first photosensitive member, a first charging member, a first developing device, a first transfer portion, and a first pre-exposure device, a second image forming portion including a second photosensitive member, a second charging member, a second developing device, a second transfer portion, and a second pre-exposure device, a current detecting portion, and an adjusting portion for adjusting an exposure amount of the first photosensitive member by the first pre-exposure device on the basis of a detection result of the detecting portion in a region on the first photosensitive member having contacted a toner band formed in a maximum amount per unit area on the intermediary transfer member by the second image forming portion in a state in which a transfer current is supplied.

Abstract: In an image forming apparatus including a plurality of image forming stations, on the basis of a density of a toner image formed in an upstream image forming station, an operation of a pre-exposure device in a downstream image forming station is controlled.

Abstract: A control portion switches first and second modes based on information which influences a toner charging amount. In the first mode, a driving input to the developer bearing member is stopped in response to image formation completion before or at the same time when a trailing end of a charging area reaches the development position, and an application of the development voltage is stopped after the trailing end reaches the development position. In the second mode, The driving input to the developer bearing member is stopped in response to image formation completion before or at the same time when the trailing end reaches the development position, and the application of the development voltage is stopped at a timing after the trailing end reaches the development position and earlier than that in the first mode, or at the same time when the trailing end reaches the development position.

Abstract: When attachment of an unused photoconductor unit is detected, a mode is executed in which, during non-image formation, a first current flowing in a charging roller is detected when a photoconductor is re-charged without irradiation of light by a pre-exposure device after being charged and passing through a transfer position during non-image formation, and a second current flowing in the charging roller is detected when the photoconductor is re-charged with irradiation of light by the pre-exposure device after being charged and passing through the transfer position, and a current supplied to an LED lamp during image formation is controlled in accordance with detection results.

Abstract: An image forming apparatus includes an intermediary transfer member, a first image forming portion including a first photosensitive member, a first charging member, a first developing device, a first transfer portion, and a first pre-exposure device, a second image forming portion including a second photosensitive member, a second charging member, a second developing device, a second transfer portion, and a second pre-exposure device, a current detecting portion, and an adjusting portion for adjusting an exposure amount of the first photosensitive member by the first pre-exposure device on the basis of a detection result of the detecting portion in a region on the first photosensitive member having contacted a toner band formed in a maximum amount per unit area on the intermediary transfer member by the second image forming portion in a state in which a transfer current is supplied.

Abstract: A control portion switches first and second modes based on information which influences a toner charging amount. In the first mode, a driving input to the developer bearing member is stopped in response to image formation completion before or at the same time when a trailing end of a charging area reaches the development position, and an application of the development voltage is stopped after the trailing end reaches the development position. In the second mode, The driving input to the developer bearing member is stopped in response to image formation completion before or at the same time when the trailing end reaches the development position, and the application of the development voltage is stopped at a timing after the trailing end reaches the development position and earlier than that in the first mode, or at the same time when the trailing end reaches the development position.

Abstract: An image forming apparatus includes a rotatable photosensitive member; a charger for charging the photosensitive member by being supplied with a DC voltage; an image forming station for forming an image on the photosensitive member charged by the charger to form an electrostatic image; a current detector for detecting a DC current flowing to the charger when the charger is supplied with a DC voltage from the voltage source; an executing portion for executing pre-charging operation for charging by the charger the photosensitive member a which is rotating, after production of an image formation signal prior to image forming operation by the image forming station; and a controller for controlling an amount of rotation of the photosensitive member in the pre-charging operation on the basis of a DC current detected by the current detector during the pre-charging operation.

Abstract: When attachment of an unused photoconductor unit is detected, a mode is executed in which, during non-image formation, a first current flowing in a charging roller is detected when a photoconductor is re-charged without irradiation of light by a pre-exposure device after being charged and passing through a transfer position during non-image formation, and a second current flowing in the charging roller is detected when the photoconductor is re-charged with irradiation of light by the pre-exposure device after being charged and passing through the transfer position, and a current supplied to an LED lamp during image formation is controlled in accordance with detection results.

Abstract: An image forming apparatus includes a rotatable photosensitive member; a charger for charging the photosensitive member by being supplied with a DC voltage; an image forming station for forming an image on the photosensitive member charged by the charger to form an electrostatic image; a current detector for detecting a DC current flowing to the charger when the charger is supplied with a DC voltage from the voltage source; an executing portion for executing pre-charging operation for charging by the charger the photosensitive member a which is rotating, after production of an image formation signal prior to image forming operation by the image forming station; and a controller for controlling an amount of rotation of the photosensitive member in the pre-charging operation on the basis of a DC current detected by the current detector during the pre-charging operation.

Abstract: An image forming apparatus includes: a drum; a charger; a developing portion; a transfer portion; a first adjuster; a second adjuster; and a controller for controlling the first and second adjuster. A first voltage is applied to the first adjuster during a period from a time when a rear end of a region in which an electrostatic image corresponding to a final image is to be formed passes through the first adjuster until a time when the rear end passes through the charger. The first voltage is lower in absolute value than a voltage applied to the first adjuster. A second voltage is applied to the second adjuster when a front end of a region of the drum opposing the first adjuster to which the first voltage is applied reaches the second adjuster. The second voltage is higher in absolute value than the voltage applied to the second adjuster.

Abstract: An image forming apparatus includes an image bearing member, a first toner charging member, provided downstream of a transfer device and upstream of a charging device with respect to a rotational direction of the image bearing member, for electronically charging toner remaining on the image bearing member, and a second toner charging member, provided downstream of the first toner charging member and upstream of the charging device with respect to the rotational direction, for electrically charging the toner remaining on the image bearing member by being supplied with a voltage of a polarity identical to a normal charge polarity of the toner. In addition, a controller controls application of a predetermined voltage to the first toner charging member, and a first AC voltage is applied to a developer.

Abstract: An image forming apparatus includes an image bearing member; a brush roller, rotatable in a predetermined rotational direction, contacted to the image bearing member; and an applying device for applying a bias to the brush roller. The brush roller includes a shaft and a woven fabric brush including fibers planted in a strip-like base material, which is wound helically about the shaft with a helical winding gap. The woven fabric brush is subjected to fiber slanting processing so that the fibers of the helically wound woven fabric brush are slanted, so as to cover the helical winding gap, from a downstream side toward an upstream side with respect to a longitudinal direction in which a helically extending widthwise edge of the base material appears to be moving when the brush roller rotates in the predetermined rotational direction.

Abstract: An image forming apparatus includes: a drum; a charger; a developing portion; a transfer portion; a first adjuster; a second adjuster; and a controller for controlling the first and second adjuster. A first voltage is applied to the first adjuster during a period from a time when a rear end of a region in which an electrostatic image corresponding to a final image is to be formed passes through the first adjuster until a time when the rear end passes through the charger. The first voltage is lower in absolute value than a voltage applied to the first adjuster. A second voltage is applied to the second adjuster when a front end of a region of the drum opposing the first adjuster to which the first voltage is applied reaches the second adjuster. The second voltage is higher in absolute value than the voltage applied to the second adjuster.

Abstract: An image forming apparatus includes: a drum; a charger; a developing portion; a transfer portion; a first adjuster; a second adjuster; and a controller for controlling the first and second adjuster. A predetermined voltage is applied to the first adjuster during a period from a time when a rear end of a region in which an electrostatic image corresponding to a final image is to be formed passes through the first adjuster until the time when the rear end passes through the charger. The predetermined voltage is lower in absolute value than a voltage applied to the first adjuster. An AC voltage is applied to the developing portion when a front end of a region of the drum opposing the first adjuster to which the predetermined voltage is applied reaches the developing portion. The AC voltage is higher in peak-to-peak voltage than the voltage applied to the developing portion.