Abstract: An image forming apparatus includes an image forming portion, a belt, a plurality of stretching rollers including an inner roller and an upstream roller, an outer member, an urging member, a first position changing mechanism, a storing portion, a controller, and an operating portion. The controller controls the first position changing mechanism on the basis of a kind of a recording material on which an image is formed, first set information stored in the storing portion, and first input information for changing setting of a position of the urging member inputted to the controller through the operating portion.

Abstract: An image forming apparatus includes an image forming portion, a rotatable endless belt, a plurality of stretching rollers including an inner roller and an upstream roller, an outer member, a guiding member, a sheet-like pressing member, and a coating member. The coating member is disposed on the pressing member so as not to contact the belt and is electrically grounded or electrically conducted to the guiding member. The coating member is formed of a material lower in surface resistivity than the pressing member.

Abstract: An image forming apparatus 100, which carries out constant-voltage control of a voltage applied to a transfer member 8 and is capable of executing limiter control for controlling the voltage applied to the transfer member 8 based on a detection result of a current detecting portion 21 so that the detection result falls within a predetermined range, is capable of executing a first mode in which a toner image is transferred onto a recording material P and a second mode in which a plurality of test toner images are transferred onto the recording material P by applying a plurality of different voltages to the transfer member 8, and a controller 50 is capable of carrying out the limiter control while the recording material P passes through the transfer portion 8 in executing the first mode and does not carry out the limiter control while an area onto which the plurality of test images are transferred passes through a transfer portion N2 in executing the second mode.

Abstract: An image forming apparatus includes an image bearing member, an intermediary transfer belt, a transfer member, a voltage source for applying a voltage to the transfer member, a detecting portion for detecting a current flowing through the transfer member, and a controller for carrying out constant-voltage control so that the voltage applied to the transfer member becomes a target voltage when a recording material P passes through a transfer portion. The controller is capable of changing the voltage applied to the transfer member so that a detection result detected by the detecting portion during transfer falls within a predetermined range. The controller changes the predetermined range on the basis of the detection result detected by the detecting portion when the voltage is applied to the transfer member in a state in which the recording material P is absent in the transfer portion.

Abstract: An image forming apparatus, which carries out constant-voltage control of a voltage applied to a transfer member and is capable of executing limiter control for controlling the voltage applied to the transfer member based on a detection result of a current detecting portion so that the detection result falls within a predetermined range, is capable of executing a first mode in which a toner image is transferred onto a recording material and a second mode in which a plurality of test toner images are transferred onto the recording material by applying a plurality of different voltages to the transfer member. A controller is capable of carrying out the limiter control while the recording material passes through the transfer portion in executing the first mode and does not carry out the limiter control while an area onto which the plurality of test images are transferred passes through a transfer portion in executing the second mode.

Abstract: An image forming apparatus includes an image forming portion, a rotatable endless belt, a plurality of stretching rollers including an inner roller and an upstream roller, an outer member, a guiding member, a sheet-like pressing member, and a coating member. The coating member is disposed on the pressing member so as not to contact the belt and is electrically grounded or electrically conducted to the guiding member. The coating member is formed of a material lower in surface resistivity than the pressing member.

Abstract: An image forming apparatus includes an image forming portion, a belt, a plurality of stretching rollers including an inner roller and an upstream roller, an outer member, an urging member, a first position changing mechanism, a storing portion, a controller, and an operating portion. The controller controls the first position changing mechanism on the basis of a kind of a recording material on which an image is formed, first set information stored in the storing portion, and first input information for changing setting of a position of the urging member inputted to the controller through the operating portion.

Abstract: An image forming apparatus 100, which carries out constant-voltage control of a voltage applied to a transfer member 8 and is capable of executing limiter control for controlling the voltage applied to the transfer member 8 based on a detection result of a current detecting portion 21 so that the detection result falls within a predetermined range, is capable of executing a first mode in which a toner image is transferred onto a recording material P and a second mode in which a plurality of test toner images are transferred onto the recording material P by applying a plurality of different voltages to the transfer member 8, and a controller 50 is capable of carrying out the limiter control while the recording material P passes through the transfer portion 8 in executing the first mode and does not carry out the limiter control while an area onto which the plurality of test images are transferred passes through a transfer portion N2 in executing the second mode.

Abstract: An image forming apparatus includes an image forming portion, a belt, a plurality of stretching rollers including an inner roller and an upstream roller, an outer member, an urging member, a first position changing mechanism, a storing portion, a controller, and an operating portion. The controller controls the first position changing mechanism on the basis of a kind of a recording material on which an image is formed, first set information stored in the storing portion, and first input information for changing setting of a position of the urging member inputted to the controller through the operating portion.

Abstract: An image forming apparatus includes an image bearing member, an intermediary transfer belt, a transfer member, a voltage source for applying a voltage to the transfer member, a detecting portion for detecting a current flowing through the transfer member, and a controller for carrying out constant-voltage control so that the voltage applied to the transfer member becomes a target voltage when a recording material P passes through a transfer portion. The controller is capable of changing the voltage applied to the transfer member so that a detection result detected by the detecting portion during transfer falls within a predetermined range. The controller changes the predetermined range on the basis of the detection result detected by the detecting portion when the voltage is applied to the transfer member in a state in which the recording material P is absent in the transfer portion.

Abstract: An image forming apparatus includes an image forming portion, a belt, an inner roller, an outer member, an inner roller position changing mechanism, an acquiring portion, and a controller. In a case that information acquired by the acquiring portion shows that first and second recording materials are coated paper, the controller controls a position changing mechanism so that a position of the inner roller when a toner image is transferred onto the second recording material is changed to a second position. In a case that the information acquired by the acquiring portion shows that the first and second recording materials are plain paper, the controller controls the position changing mechanism so that the position of the inner roller when the toner image is transferred onto the second recording material is maintained at a first position.

Abstract: An image forming apparatus 100, which carries out constant-voltage control of a voltage applied to a transfer member 8 and is capable of executing limiter control for controlling the voltage applied to the transfer member 8 based on a detection result of a current detecting portion 21 so that the detection result falls within a predetermined range, is capable of executing a first mode in which a toner image is transferred onto a recording material P and a second mode in which a plurality of test toner images are transferred onto the recording material P by applying a plurality of different voltages to the transfer member 8, and a controller 50 is capable of carrying out the limiter control while the recording material P passes through the transfer portion 8 in executing the first mode and does not carry out the limiter control while an area onto which the plurality of test images are transferred passes through a transfer portion N2 in executing the second mode.

Abstract: An image forming apparatus includes an image bearing member, an intermediary transfer belt, a transfer member, a voltage source for applying a voltage to the transfer member, a detecting portion for detecting a current flowing through the transfer member, and a controller for carrying out constant-voltage control so that the voltage applied to the transfer member becomes a target voltage when a recording material P passes through a transfer portion. The controller is capable of changing the voltage applied to the transfer member so that a detection result detected by the detecting portion during transfer falls within a predetermined range. The controller changes the predetermined range on the basis of the detection result detected by the detecting portion when the voltage is applied to the transfer member in a state in which the recording material P is absent in the transfer portion.

Abstract: An image forming apparatus includes an image forming portion, a belt, a plurality of stretching rollers including an inner roller and an upstream roller, an outer member, an urging member, a first position changing mechanism, a storing portion, a controller, and an operating portion. The controller controls the first position changing mechanism on the basis of a kind of a recording material on which an image is formed, first set information stored in the storing portion, and first input information for changing setting of a position of the urging member inputted to the controller through the operating portion.

Abstract: An image forming apparatus includes an image forming portion, a belt, an inner roller, an outer member, an inner roller position changing mechanism, an acquiring portion, and a controller. In a case that second information acquired by the acquiring portion shows that first and second recording materials are coated paper, the controller controls a position changing mechanism so that a position of the inner roller when a toner image is transferred onto the second recording material is changed to a second position. In a case that the second information acquired by the acquiring portion shows that the first and second recording materials are plain paper, the controller controls the position changing mechanism so that the position of the inner roller when the toner image is transferred onto the second recording material is maintained at a first position.

Abstract: An image forming apparatus includes an image bearing member, a transfer member, a voltage source, a current detecting portion, a controller, and a receiving portion. During the recording material passing through the transfer portion, the controller controls a voltage applied to a transfer member on the basis of a detection result of the current detecting portion so that a current flowing through the transfer member falls within a predetermined range. The controller sets at least one of an upper limit and a lower limit of the predetermined range on the basis of a predetermined voltage changing instruction received by the receiving portion.

Abstract: An information which includes an image bearing member 1, an intermediary transfer belt 7, a transfer member 8, a voltage source 20 for applying a voltage to the transfer member 8, a detecting portion 21 for detecting a current flowing through the transfer member 8, and a controller 50 for carrying out constant-voltage control so that the voltage applied to the transfer member when a recording material P passes through a transfer portion N2 and in which the controller 50 is capable of changing the voltage applied to the transfer member 8 so that a detection result detected by the detecting portion 21 during transfer falls within a predetermined pass has a constitution in which said controller 50 changes the predetermined range on the basis of the detection result detected by the detecting portion 21 when the voltage is applied to the transfer member 8 in a state in which the recording material P is absent in the transfer portion N2.

Abstract: An image forming apparatus includes an image bearing member, a transfer member, a voltage source, a current detecting portion, a controller, and a receiving portion. During the recording material being passing through the transfer portion, the controller controls a voltage applied to a transfer member on the basis of a detection result of the current detecting portion so that a current flowing through the transfer member falls within a predetermined range. The controller sets at least one of an upper limit and a lower limit of the predetermined range on the basis of a predetermined voltage changing instruction received by the receiving portion.

Abstract: An image forming apparatus including: an image bearing member; a transfer member; a power supply; a conveyance path; a first detection portion; a second detection portion; and a controller configured to control a bias to be applied to the transfer member, wherein the controller controls a voltage to be applied to the transfer member when a first region of a recording material passes through a transfer portion, based on a detection result obtained by detecting the first region of the recording material by the first detection portion and a detection result obtained by detecting a second region of the recording material which is downstream of the first region with respected to a conveying direction of the recording material by the first detection portion, and a detection result detected by the second detection portion at a timing when the second region passes through the transfer portion.

Abstract: An image forming apparatus includes a belt, image forming unit, first and second transfer rollers, feeding portion, stretching roller and urging member. Regarding (1) a contact point between (i) an outer common tangential line between the stretching and first transfer rollers and (ii) the first transfer roller and (2) an intersection point between (i) the outer common tangential line and (ii) a line perpendicular to the outer common tangential line and passing through a rotation center of the second transfer roller, the contact point is closer to the stretching roller than the intersection point is to the stretching roller and a distance between the contact and intersection points is 5% or more of a diameter of the first transfer roller. The urging member urges the belt from an inner belt surface at a position, close to a transfer portion, between the first transfer roller and the belt.