Abstract: An image forming apparatus includes a transfer portion, a fixing portion to fix the toner image onto the sheet, and a charge adjusting portion. The charge adjusting portion adjusts charge to the sheet on which the toner image is fixed. The charge adjusting portion is provided with first and second rollers, a supplying rotatable member and a power source. The first roller includes a shaft having conductivity and an outer circumferential portion including an ion conductive material formed on an outer periphery of the shaft, and is electrically floating. The second roller is disposed so as to nip the sheet between itself and the first roller. The supplying rotatable member is in contact with the first roller and supplies a current to the first roller. The power source applies a voltage of one polarity of a positive polarity and a negative polarity to the supplying rotatable member.

Abstract: An image forming apparatus includes a transfer portion, a fixing portion to fix the toner image onto the sheet, and a charge adjusting portion. The charge adjusting portion adjusts charge to the sheet on which the toner image is fixed. The charge adjusting portion is provided with first and second rollers, a supplying rotatable member and a power source. The first roller includes a shaft having conductivity and an outer circumferential portion including an ion conductive material formed on an outer periphery of the shaft, and is electrically floating. The second roller is disposed so as to nip the sheet between itself and the first roller. The supplying rotatable member is in contact with the first roller and supplies a current to the first roller. The power source applies a voltage of one polarity of a positive polarity and a negative polarity to the supplying rotatable member.

Abstract: An image forming apparatus includes a belt, an outer roller, stretching rollers including an inner roller and an upstream roller, a voltage source, a supporting member, a moving mechanism, a sensor, and a controller. On the basis of a first detection result of the sensor acquired under application of a test bias in a state in which the supporting member is disposed at a first position, the controller determines a first transfer bias to be applied to the outer roller or the inner roller during an operation in a first mode. On the basis of a second detection result of the sensor acquired under application of the test bias in the state in which the supporting member is disposed at a second position, the controller determines a second transfer bias to be applied to the outer roller or the inner roller during an operation in a second mode.

Abstract: An image forming apparatus includes a belt, an outer roller, stretching rollers including an inner roller and an upstream roller, a voltage source, a supporting member, a moving mechanism, a sensor, and a controller. On the basis of a first detection result of the sensor acquired under application of a test bias in a state in which the supporting member is disposed at a first position, the controller determines a first transfer bias applied to the outer roller or the inner roller during an operation in a first mode. On the basis of a second detection result of the sensor acquired under application of the test bias in the state in which the supporting member is disposed at a second position, the controller determines a second transfer bias applied to the outer roller or the inner roller during an operation in a second mode.

Abstract: An image forming apparatus includes a discharging device that discharges a sheet to which a toner image is transferred. The discharging device is disposed on a side opposite to a transfer surface of the sheet to which the toner image is transferred downstream from a nip portion between an intermediate transfer belt and an external secondary transfer roller in a sheet conveyance direction. The discharging device includes a grounded first discharging plate, and a grounded second discharging plate which is disposed downstream from the first discharging plate in the sheet conveyance direction at an angle different from an angle of the first discharging plate.

Abstract: An image forming apparatus includes a discharging device that discharges a sheet to which a toner image is transferred. The discharging device is disposed on a side opposite to a transfer surface of the sheet to which the toner image is transferred downstream from a nip portion between an intermediate transfer belt and an external secondary transfer roller in a sheet conveyance direction. The discharging device includes a grounded first discharging plate, and a grounded second discharging plate which is disposed downstream from the first discharging plate in the sheet conveyance direction at an angle different from an angle of the first discharging plate.

Abstract: An image forming apparatus includes image bearing members; an image forming unit; a movable endless belt, transfer members provided in contact with an inner peripheral surface of the belt and in neighborhoods of the transfer portions, wherein each of the transfer members is disposed at a position shifted toward a downstream side relative to an associated contact portion with respect to a movement direction of the belt, a voltage source, and an urging member for urging the belt to an associated image bearing member in contact with the inner peripheral surface of the belt. The urging member is provided correspondingly to at least one of the image bearing members.

Abstract: An image forming apparatus includes an image bearing member; a stretched rotatable belt member; a transfer device for forming a transfer portion where a toner image is transferred from the image bearing member onto a recording material carried and conveyed on the belt member; a separation roller capable of separating the recording material from the belt member; a push-up device capable of pushing up a belt surface locally with respect to a widthwise direction of the belt member to separate the recording material from the belt member; and an execution portion for executing, when an abnormality occurs during an image forming operation, an operation in a stop mode in which the belt member is, after the image forming operation is stopped, rotated in a push-up state of the push-up device and then the rotation of the belt member is stopped.

Abstract: An image forming apparatus includes an intermediary transfer member having an elastic layer; a toner image forming portion for forming a toner image for an image to be carried on the intermediary transfer member; a transfer member, which presses the intermediary transfer member, for transferring the toner image for the image from the intermediary transfer member onto a recording material; a pressing mechanism capable of changing pressure applied from the transfer member to the intermediary transfer member; and a controller for controlling the toner image forming portion so that a length of the toner image for the image on the intermediary transfer member with respect to a rotational direction of the intermediary transfer member is decreased with an increase of the pressure.

Abstract: An image forming apparatus comprising: an image bearing member; a conveying member; a transfer means; an attraction means, which is disposed upstream of the transfer means in a conveying direction of the transfer material, for attracting the transfer material onto the conveying member; and a winding means, which is disposed downstream of the transfer means in the conveying direction of the transfer material, for winding the conveying member, wherein a contact amount between the conveying member and the winding means corresponding to a first region where a width of the attraction means pressing the conveying member in the conveying direction is smaller than the contact amount between the conveying member and the winding means corresponding to a second region in which a width of the attraction means which presses the conveying member in the conveying direction that is smaller than the first width.

Abstract: An image forming apparatus includes an image bearing member; an image forming portion for forming a toner image on the image bearing member, the image forming portion being capable of forming an image to be formed on a recording material and forming a control image for controlling an image density at a position adjacent to the image to be formed on the recording material; an intermediary transfer member rotatable while carrying the toner image transferred from the image bearing member; a transfer member for forming a transfer portion where the toner image is to be transferred from the intermediary transfer member onto the recording material; an electrostatic cleaning member for electrostatically removing the toner deposited on the transfer member; a density detecting portion, provided upstream of the transfer member with respect to a rotational direction of the intermediary transfer member, for detecting a density of the control image transferred on the intermediary transfer member; an adjusting portion for a

Abstract: An image forming apparatus includes an image forming device for forming a toner image on an image conveying member on the basis of an input image signal; a transfer device for transferring the toner image from the image conveying member onto an image receiving member; a bias applying device for applying a transfer bias to the transfer device when the toner image is transferred from the image conveying member onto the image receiving member; an executing portion for executing a test mode in which a test image is formed on the image conveying member and is then transferred onto the image receiving member; a detecting device for detecting a current passing through the transfer device in the test mode; a control device for controlling an image forming condition of the image forming device on the basis of an output of the detecting device; and a setting device for setting a test bias to be applied from the bias applying device at a value larger than the transfer bias in terms of an absolute value.

Abstract: An image forming apparatus includes an image bearing member; a stretched rotatable belt member; a transfer device for forming a transfer portion where a toner image is transferred from the image bearing member onto a recording material carried and conveyed on the belt member; a separation roller capable of separating the recording material from the belt member; a push-up device capable of pushing up a belt surface locally with respect to a widthwise direction of the belt member to separate the recording material from the belt member; and an execution portion for executing, when an abnormality occurs during an image forming operation, an operation in a stop mode in which the belt member is, after the image forming operation is stopped, rotated in a push-up state of the push-up device and then the rotation of the belt member is stopped.

Abstract: An image forming apparatus includes an intermediary transfer member having an elastic layer; a toner image forming portion for forming a toner image for an image to be carried on the intermediary transfer member; a transfer member, which presses the intermediary transfer member, for transferring the toner image for the image from the intermediary transfer member onto a recording material; a pressing mechanism capable of changing pressure applied from the transfer member to the intermediary transfer member; and a controller for controlling the toner image forming portion so that a length of the toner image for the image on the intermediary transfer member with respect to a rotational direction of the intermediary transfer member is decreased with an increase of the pressure.

Abstract: In an image forming apparatus, when backside contamination of a recording material occurs, a control portion carries out control so that a plurality of restoring toner bands having a length L1 longer than a circumference L3 of a secondary transfer roller is formed at an interval L2 at positions in which the restoring toner bands can overlap with control images with respect to a longitudinal direction of the secondary transfer roller and then is transferred onto the secondary transfer roller through an intermediary transfer belt. The restoring toner bands transferred onto the secondary transfer roller stagnate on a fur brush rubbing against the secondary transfer roller to remove an electric discharge product deposited on the secondary transfer roller. The toner stagnating on the fur brush is inverted in charge polarity and then is re-transferred onto the intermediary transfer belt through the secondary transfer roller.

Abstract: An image forming apparatus includes an image bearing member; an image forming portion for forming a toner image on the image bearing member, the image forming portion being capable of forming an image to be formed on a recording material and forming a control image for controlling an image density at a position adjacent to the image to be formed on the recording material; an intermediary transfer member rotatable while carrying the toner image transferred from the image bearing member; a transfer member for forming a transfer portion where the toner image is to be transferred from the intermediary transfer member onto the recording material; an electrostatic cleaning member for electrostatically removing the toner deposited on the transfer member; a density detecting portion, provided upstream of the transfer member with respect to a rotational direction of the intermediary transfer member, for detecting a density of the control image transferred on the intermediary transfer member; an adjusting portion for a

Abstract: When a switch displayed on an operation panel is operated, a control portion starts aging control in which image formation is stopped and yellow toner is applied onto an intermediary transfer belt and a secondary transfer roller. A toner band is formed, on full circumference of the intermediary transfer belt at a position in which toner images for control are formed, with a width correspondingly to widths of the toner images for control.

Abstract: An image forming apparatus comprising: an image bearing member; a conveying member; a transfer means; an attraction means, which is disposed upstream of the transfer means in a conveying direction of the transfer material, for attracting the transfer material onto the conveying member; and a winding means, which is disposed downstream of the transfer means in the conveying direction of the transfer material, for winding the conveying member, wherein a contact amount between the conveying member and the winding means corresponding to a first region where a width of the attraction means pressing the conveying member in the conveying direction is smaller than the contact amount between the conveying member and the winding means corresponding to a second region in which a width of the attraction means which presses the conveying member in the conveying direction that is smaller than the first width.

Abstract: An image forming apparatus includes an image forming device for forming a toner image on an image conveying member on the basis of an input image signal; a transfer device for transferring the toner image from the image conveying member onto an image receiving member; a bias applying device for applying a transfer bias to the transfer device when the toner image is transferred from the image conveying member onto the image receiving member; an executing portion for executing a test mode in which a test image is formed on the image conveying member and is then transferred onto the image receiving member; a detecting device for detecting a current passing through the transfer device in the test mode; a control device for controlling an image forming condition of the image forming device on the basis of an output of the detecting device; and a setting device for setting a test bias to be applied from the bias applying device at a value larger than the transfer bias in terms of an absolute value.

Abstract: An image forming apparatus includes an image bearing member for bearing a toner image, a transfer member for forming a transfer portion for transferring the toner image onto a recording material in contact with the image bearing member, a vibration imparting portion for imparting vibration at a variable frequency to the recording material having passed through the transfer portion, and a control portion for controlling the frequency by the vibration imparting portion so that the frequency is decreased with an increasing length of the recording material having passed through the transfer portion during a process of passing the recording material through the transfer portion.