Abstract: The control unit executes a mode of detecting the image density of the toner image for control. The control unit sets the target toner density so that the target toner density becomes smaller than before execution of the mode and also set the target transfer current so that the target transfer current becomes smaller, in a case where the image density detected in the mode is higher by a predetermined threshold or more than a reference density.

Abstract: In an image forming apparatus, a cleaning blade, disposed on a downstream side of a transfer roller in a rotation direction of an image carrier, removes toner remaining on the image carrier after transfer of a toner image to an intermediate transfer member. After completion of an image forming operation, a controller causes the transfer roller to separate from the intermediate transfer member, cause the developing device to form on the image carrier a toner band to be supplied to the cleaning blade, and cause rotation of the image carrier to stop such that at least a part of the toner band formed on the image carrier stops within a section from a first position facing the transfer roller to a second position facing the cleaning blade in the rotation direction.

Abstract: In an image forming apparatus, a cleaning blade, disposed on a downstream side of a transfer roller in a rotation direction of an image carrier, removes toner remaining on the image carrier after transfer of a toner image to an intermediate transfer member. After completion of an image forming operation, a controller causes the transfer roller to separate from the intermediate transfer member, cause the developing device to form on the image carrier a toner band to be supplied to the cleaning blade, and cause rotation of the image carrier to stop such that at least a part of the toner band formed on the image carrier stops within a section from a first position facing the transfer roller to a second position facing the cleaning blade in the rotation direction.

Abstract: The control unit executes a mode of detecting the image density of the toner image for control. The control unit sets the target toner density so that the target toner density becomes smaller than before execution of the mode and also set the target transfer current so that the target transfer current becomes smaller, in a case where the image density detected in the mode is higher by a predetermined threshold or more than a reference density.

Abstract: An image forming apparatus includes a photosensitive member, a rotatable intermediate transfer belt configured to come into contact with a photosensitive member at a first contact portion on an outer peripheral surface thereof, and, a transfer member configured to come into contact with an inner peripheral surface of the intermediate transfer belt at a second contact portion. The transfer member is disposed such that an upstream end of the second contact portion is positioned downstream of a downstream end of the first contact portion in the rotation direction of the intermediate transfer belt. In a case where a surface resistivity measured on the outer peripheral surface of the intermediate transfer belt is G and a surface resistivity measured on the inner peripheral surface of the intermediate transfer belt is N, 0.75?N/G?1.2 is satisfied.

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 an image bearing member, a transfer roller, an electric energy supply member, a voltage source, a detector, and a controller for adjusting a transfer voltage. A circumferential length 2K of the transfer roller and a distance k measured along an outer periphery of the transfer roller from the electric energy supplying member to the transfer roller satisfy 0.8K?k?1.2K. The controller controls the voltage source so as to satisfy 0.7T?t?1.3T, where 2T is time required for one full rotation of the transfer roller, and t is time during which the voltage source supplies the test current or the test voltage per one level in the operation of a setting mode.

Abstract: An image forming apparatus includes an image bearing member 7, a transfer roller 8, an electric energy supply member 9, a voltage source E2, a detecting means 32 a controlling means 50 for adjusting a transfer voltage. A circumferential length 2K of the transfer roller, and a distance k measured along an outer periphery of the transfer roller from the electric energy supplying portion to the transfer portion satisfy 0.8K?k?1.2K. The controller controls the voltage source so as to satisfy 0.7T?t?1.3T, where 2T is time required for one full rotation of the transfer roller, and t is time during which the voltage source supplies in the test current or the test voltage per one level in the operation of the setting mode.

Abstract: An image forming apparatus includes a photosensitive member, a rotatable intermediate transfer belt configured to come into contact with a photosensitive member at a first contact portion on an outer peripheral surface thereof, and, a transfer member configured to come into contact with an inner peripheral surface of the intermediate transfer belt at a second contact portion. The transfer member is disposed such that an upstream end of the second contact portion is positioned downstream of a downstream end of the first contact portion in the rotation direction of the intermediate transfer belt. In a case where a surface resistivity measured on the outer peripheral surface of the intermediate transfer belt is G and a surface resistivity measured on the inner peripheral surface of the intermediate transfer belt is N, 0.75?N/G?1.2 is satisfied.

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 control unit configured to execute a first mode and a second mode of forming images on first through third image bearing members. In the first mode, a toner image is formed on a third image bearing member without having toner images formed on the first and second image bearing members in a state where the first through third image bearing members are abutted against an intermediate transfer body. In the first mode, the control unit controls at least a first charging device such that a primary transfer contrast in a first primary transfer portion is set to be equal to or greater than a discharge starting voltage, and applies an AC voltage to a second charging device such that a discharge current having a current quantity smaller than that in the second mode is supplied.

Abstract: An image forming apparatus includes an image bearing member, a developing apparatus, a toner supply portion, a toner density detection portion, an intermediate transfer body, a secondary transfer body, an image density detection unit, and a control unit. The control unit sets a transfer condition of at least either a primary transfer portion or a secondary transfer portion based on an image density being detected by the image density detection unit in a state where a target toner density set based on the image density being detected reaches a limit value of a predetermined setting range.

Abstract: An image forming apparatus includes an image bearing member, a transfer body, a bias applying portion, a current detection unit, and a control unit. The control unit is configured to change the upper limit voltage based on the current detected by the current detection unit in a state where a test bias is applied to the transfer portion during a non-image forming period, and a voltage of the test bias being applied.

Abstract: An image forming apparatus includes an image bearing member, a transfer body, a bias applying portion, a current detection unit, and a control unit. The control unit is configured to change the upper limit voltage based on the current detected by the current detection unit in a state where a test bias is applied to the transfer portion during a non-image forming period, and a voltage of the test bias being applied.

Abstract: An image forming apparatus includes an image bearing member, a developing apparatus, a toner supply portion, a toner density detection portion, an intermediate transfer body, a secondary transfer body, an image density detection unit, and a control unit. The control unit sets a transfer condition of at least either a primary transfer portion or a secondary transfer portion based on an image density being detected by the image density detection unit in a state where a target toner density set based on the image density being detected reaches a limit value of a predetermined setting range.

Abstract: An image forming apparatus includes a rotatable image drum for carrying a toner image; a transfer member contacted to the drum to transfer the toner image from the drum onto a transfer member; a cleaning blade provided downstream of the transfer member with respect to a peripheral moving direction of the drum and having a free end portion contacted to the drum, the blade being configured to remove, with rotation of the drum, toner remaining on the drum after transfer of the toner image by the transfer member; and a toner retaining member cooperative with the drum to provide a toner accommodation space toner removed from the drum by the blade. The toner retaining member can retain a part of the toner accommodated in the toner accommodation space and capable of being deformed by the toner accommodated in the accommodation space to discharge the toner from the accommodation space.

Abstract: An image forming apparatus includes a toner image forming portion, an endless belt, first, second, and third rollers, and an urging roller, and satisfies: 25 (mm)>X>(R1+R2)2?(R1?R2)2)1/2?L1)+7 (mm), 3.5 (mm)?Y>0.5 (mm), and L1>0 (mm). X is a distance between Lb passing through a rotation center of the third roller and perpendicular to an outer common tangential line L between the first and second rollers and Lc passing through a rotation center of the urging roller and L, R1 is a radius of the first roller, R2 is a radius of the urging roller, L1 is a distance between Lb and a line La passing through a rotation center of the first roller and L, and Y is a distance between L and a tangential line Ld of the urging roller parallel to L.

Abstract: An image forming apparatus including a control unit configured to execute a first mode and a second mode of forming images on first through third image bearing members. In the first mode, a toner image is formed on a third image bearing member without having toner images formed on first and second image bearing members in a state where the first through third image bearing members are abutted against an intermediate transfer body. In the first mode, the control unit controls at least a first charging device such that a primary transfer contrast in a first primary transfer portion is set equal to or greater than a discharge starting voltage, and applies an AC voltage to a second charging device such that a discharge current having a current quantity smaller than that in the second mode.

Abstract: An image forming apparatus includes a toner image forming portion, an endless belt, first, second, and third rollers, and an urging roller, and satisfies: 25 (mm)>X>(R1+R2)2?(R1?R2)2)1/2?L1)+7 (mm), 3.5 (mm)?Y>0.5 (mm), and L1>0 (mm). X is a distance between Lb passing through a rotation center of the third roller and perpendicular to an outer common tangential line L between the first and second rollers and Lc passing through a rotation center of the urging roller and L, R1 is a radius of the first roller, R2 is a radius of the urging roller, L1 is a distance between Lb and a line La passing through a rotation center of the first roller and L, and Y is a distance between L and a tangential line Ld of the urging roller parallel to L.

Abstract: An image forming apparatus includes a rotatable image drum for carrying a toner image; a transfer member contacted to the drum to transfer the toner image from the drum onto a transfer member; a cleaning blade provided downstream of the transfer member with respect to a peripheral moving direction of the drum and having a free end portion contacted to the drum, the blade being configured to remove, with rotation of the drum, toner remaining on the drum after transfer of the toner image by the transfer member; and a toner retaining member cooperative with the drum to provide a toner accommodation space toner removed from the drum by the blade. The toner retaining member can retain a part of the toner accommodated in the toner accommodation space and capable of being deformed by the toner accommodated in the accommodation space to discharge the toner from the accommodation space.