Abstract: 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.

Abstract: 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.

Abstract: An image forming apparatus includes a photosensitive drum, a primary transfer roller, first and second voltage applicators, first and second voltage controllers, a current detector, and a charging roller. The first voltage controller controls a voltage applied to the primary transfer roller through the first voltage applicator. The current detector detects a current value of a current flowing through the primary transfer roller. The second voltage controller controls a voltage applied to the charging roller through the second voltage applicator. The second voltage controller causes a voltage having a smaller absolute value than a dark potential of the photosensitive drum to be applied to the photosensitive drum during a transfer voltage control period. During the transfer voltage control period, the first voltage controller causes a voltage to be applied to the primary transfer roller, and the current detector detects the current value.

Abstract: An image forming apparatus includes a photosensitive drum, a primary transfer roller, first and second voltage applicators, first and second voltage controllers, a current detector, and a charging roller. The first voltage controller controls a voltage applied to the primary transfer roller through the first voltage applicator. The current detector detects a current value of a current flowing through the primary transfer roller. The second voltage controller controls a voltage applied to the charging roller through the second voltage applicator. The second voltage controller causes a voltage having a smaller absolute value than a dark potential of the photosensitive drum to be applied to the photosensitive drum during a transfer voltage control period. During the transfer voltage control period, the first voltage controller causes a voltage to be applied to the primary transfer roller, and the current detector detects the current value.

Abstract: A transfer device includes a conveyance belt, a transfer roller, and a stretch roller. The conveyance belt is in contact with an image carrier that carries a toner image, and conveys a sheet via a contact position with the image carrier. A voltage having a polarity opposite to a charging polarity of toner that forms the toner image is applied to the transfer roller, and the transfer roller transfers the toner image carried by the image carrier onto the sheet at the contact position. The stretch roller stretches the conveyance belt at a separation position in which the sheet is separated from the conveyance belt and which is downstream of the contact position in a conveyance direction in which the sheet is conveyed by the conveyance belt, and the voltage having the polarity opposite to the charging polarity of the toner is applied to the stretch roller.

Abstract: An image forming apparatus includes development sections having development rollers, photosensitive drums, primary transfer rollers disposed opposite to the photosensitive drums in one-to-one correspondence, an intermediate transfer belt, and a voltage application section. The voltage application section includes a first voltage application section and a second voltage application section. In forced toner discharge from the development sections, the first voltage application section applies opposite polarity voltage between each of three upstream primary transfer rollers among the primary transfer rollers and the corresponding one of the photosensitive drums. The second voltage application section applies positive polarity voltage between a most downstream primary transfer roller and the corresponding one of the photosensitive drums.

Abstract: A transfer device includes a conveyance belt, a transfer roller, and a stretch roller. The conveyance belt is in contact with an image carrier that carries a toner image, and conveys a sheet via a contact position with the image carrier. A voltage having a polarity opposite to a charging polarity of toner that forms the toner image is applied to the transfer roller, and the transfer roller transfers the toner image carried by the image carrier onto the sheet at the contact position. The stretch roller stretches the conveyance belt at a separation position in which the sheet is separated from the conveyance belt and which is downstream of the contact position in a conveyance direction in which the sheet is conveyed by the conveyance belt, and the voltage having the polarity opposite to the charging polarity of the toner is applied to the stretch roller.

Abstract: An image forming apparatus (1) includes an image forming section (12), an intermediate transfer belt (125), a drive roller (125A), a secondary transfer roller (210), a brush section (80), a cleaning device (70), a power supply device (81), and a ground portion (82). The brush section (80) is disposed at a location downstream of the secondary transfer roller (210) in a direction of travel of the intermediate transfer belt (125) and facing the drive roller (125A) with the intermediate transfer belt (125) in between. A potential difference is applied between the brush section (80) and the secondary transfer roller (210) by the power supply device (81) and the ground portion (82), so that an electric current having the same polarity as a normal charge polarity flows from the brush section (80) through the drive roller (125A) to the secondary transfer roller (210).

Abstract: An image forming apparatus includes development sections having development rollers, photosensitive drums, primary transfer rollers disposed opposite to the photosensitive drums in one-to-one correspondence, an intermediate transfer belt, and a voltage application section. The voltage application section includes a first voltage application section and a second voltage application section. In forced toner discharge from the development sections, the first voltage application section applies opposite polarity voltage between each of three upstream primary transfer rollers among the primary transfer rollers and the corresponding one of the photosensitive drums. The second voltage application section applies positive polarity voltage between a most downstream primary transfer roller and the corresponding one of the photosensitive drums.

Abstract: An image forming apparatus (1) includes an image forming section (12), an intermediate transfer belt (125), a drive roller (125A), a secondary transfer roller (210), a brush section (80), a cleaning device (70), a power supply device (81), and a ground portion (82). The brush section (80) is disposed at a location downstream of the secondary transfer roller (210) in a direction of travel of the intermediate transfer belt (125) and facing the drive roller (125A) with the intermediate transfer belt (125) in between. A potential difference is applied between the brush section (80) and the secondary transfer roller (210) by the power supply device (81) and the ground portion (82), so that an electric current having the same polarity as a normal charge polarity flows from the brush section (80) through the drive roller (125A) to the secondary transfer roller (210).

Abstract: An image forming apparatus includes: a photosensitive drum; a transfer belt configured to be charged to an opposite polarity to the surface of the photosensitive drum to electrostatically attract a recording paper sheet and convey the sheet while pressing the sheet against the photosensitive drum, thereby transferring a toner image formed on the surface of the photosensitive drum to the sheet; a fixing section configured to apply heat to the recording paper sheet having the toner image transferred thereto and thus fix the toner image on the sheet; a toner collecting member disposed to face a separating position where the recording paper sheet is separated from the transfer belt and extending in a width direction of the sheet being conveyed, the toner collecting member being electrically grounded; and a thermally conductive member configured to collect heat near the fixing section and conduct the collected heat to the toner collecting member.

Abstract: A fur brush roller electrically absorbs and removes a transferred remaining toner on a surface of an image carrier through bias voltage impression. This fur brush roller includes: a foundation cloth, conductive yarns, and insulation yarns. The insulation yarns are subjected to crimp-texturizing processing. The conductive yarns and the insulation yarns are alternately pile-woven to the foundation cloth.

Abstract: An image forming apparatus includes: a photosensitive drum; a transfer belt configured to be charged to an opposite polarity to the surface of the photosensitive drum to electrostatically attract a recording paper sheet and convey the sheet while pressing the sheet against the photosensitive drum, thereby transferring a toner image formed on the surface of the photosensitive drum to the sheet; a fixing section configured to apply heat to the recording paper sheet having the toner image transferred thereto and thus fix the toner image on the sheet; a toner collecting member disposed to face a separating position where the recording paper sheet is separated from the transfer belt and extending in a width direction of the sheet being conveyed, the toner collecting member being electrically grounded; and a thermally conductive member configured to collect heat near the fixing section and conduct the collected heat to the toner collecting member.

Abstract: A fur brush roller electrically absorbs and removes a transferred remaining toner on a surface of an image carrier through bias voltage impression. This fur brush roller includes: a foundation cloth, conductive yarns, and insulation yarns. The insulation yarns are subjected to crimp-texturizing processing. The conductive yarns and the insulation yarns are alternately pile-woven to the foundation cloth.

Abstract: A developing device includes a developer supporting rotator, toner supporting rotator and voltage application unit. The toner supporting rotator is arranged opposite to a developer supporting rotator, supports toner supplied from the developer supporting rotator, and forms a toner layer by a magnetic brush. The voltage application unit causes the toner supported by the toner supporting rotator to an electrostatic latent image on a surface of an image carrier to develop it into a toner image. A longitudinal end portion of the toner supporting side magnetic member is positioned longitudinally more outside than a longitudinal end portion of the developer supporting side magnetic member. A surface of the second rotating sleeve positioned more outside than the end of the developer supporting side magnetic member is composed of a surface of low adherence with lower toner adherence and a higher dielectric constant than those of a surface positioned inside thereof.

Abstract: A developing device includes a case for housing a developer, a magnetic roller, an agitating member, a layer thickness restricting member and a plurality of projection members. The magnetic roller is arranged in the case, includes a rotary shaft and magnetically carries the developer on a circumferential surface. The agitating member is arranged to face the magnetic roller in the case, includes a shaft center and a screw forming portion arranged around the shaft center. The layer thickness restricting member restricts the layer thickness of the developer to a predetermined thickness. The plurality of projection members are arranged along a rotation axis direction of the magnetic roller to face the circumferential surface of the magnetic roller at a side upstream of the layer thickness restricting member in a rotating direction of the magnetic roller and comes into contact with the developer carried on the magnetic roller.

Abstract: A developing device includes a developer supporting rotator, toner supporting rotator and voltage application unit. The toner supporting rotator is arranged opposite to a developer supporting rotator, supports toner supplied from the developer supporting rotator, and forms a toner layer by a magnetic brush. The voltage application unit causes the toner supported by the toner supporting rotator to an electrostatic latent image on a surface of an image carrier to develop it into a toner image. A longitudinal end portion of the toner supporting side magnetic member is positioned longitudinally more outside than a longitudinal end portion of the developer supporting side magnetic member. A surface of the second rotating sleeve positioned more outside than the end of the developer supporting side magnetic member is composed of a surface of low adherence with lower toner adherence and a higher dielectric constant than those of a surface positioned inside thereof.

Abstract: A developing device is provided with a developer conveyance path for conveying a developer containing nonmagnetic toner and magnetic carrier, a wall portion including a wall surface for defining the developer conveyance path, a developing roller for supplying the toner from the developer conveyance path to an image bearing member, a conveying member extending in the developer conveyance path for conveying the developer while agitating it, a toner supply port arranged above the developer conveyance path for supplying new toner into the developer conveyance path from the outside, and a scraping member arranged at a position below the toner supply port in the developer conveyance path and adapted to scrape off the toner adhering to the wall surface while sliding in contact with the wall surface of the wall portion.

Abstract: A developing device includes a case for housing a developer, a magnetic roller, an agitating member, a layer thickness restricting member and a plurality of projection members. The magnetic roller is arranged in the case, includes a rotary shaft and magnetically carries the developer on a circumferential surface. The agitating member is arranged to face the magnetic roller in the case, includes a shaft center and a screw forming portion arranged around the shaft center. The layer thickness restricting member restricts the layer thickness of the developer to a predetermined thickness. The plurality of projection members are arranged along a rotation axis direction of the magnetic roller to face the circumferential surface of the magnetic roller at a side upstream of the layer thickness restricting member in a rotating direction of the magnetic roller and comes into contact with the developer carried on the magnetic roller.

Abstract: A developing device is provided with a developer conveyance path for conveying a developer containing nonmagnetic toner and magnetic carrier, a wall portion including a wall surface for defining the developer conveyance path, a developing roller for supplying the toner from the developer conveyance path to an image bearing member, a conveying member extending in the developer conveyance path for conveying the developer while agitating it, a toner supply port arranged above the developer conveyance path for supplying new toner into the developer conveyance path from the outside, and a scraping member arranged at a position below the toner supply port in the developer conveyance path and adapted to scrape off the toner adhering to the wall surface while sliding in contact with the wall surface of the wall portion.