Abstract: The image forming apparatus forms a test chart on an image bearing member, the test chart including a plurality of test images including a first test image of a first density and a second test image formed at a position different from a position of the first test image in a conveying direction of a recording medium, the second test image having a second density different from the first density. The image forming apparatus transfers the test chart to the recording medium with a transfer roller and controls the rotation velocity of the transfer roller when the recording medium passes through a transfer portion based on a result of reading the test chart on the recording medium with a reading unit.

Abstract: An image forming apparatus includes an image forming unit configured to form an image on a sheet, a reversing unit configured to convey a sheet conveyed from the image forming unit in a first direction, stop the conveyance, and then convey the sheet in a second direction, which is opposite to the first direction, an image detection unit disposed to detect at least a portion of the image on the sheet stopped by the reversing unit, and a control unit configured to control the reversing unit and the image detection unit. The control unit is configured to detect the image on the sheet by the image detection unit while the sheet conveyance is stopped by the reversing unit.

Abstract: A calculation system includes an obtaining unit and a calculation unit. The obtaining unit obtains information of a sheet. The calculation unit calculates an amount of change in length of the sheet in a conveyance direction of the sheet heated by a heating device to fix a toner image to the sheet based on the information of the sheet obtained by the obtaining unit and an elapsed time from a time when the sheet passes through the heating device.

Abstract: A sheet feeding apparatus includes a sheet supporting unit, a sheet feed unit, an air separation unit configured to separate the uppermost sheet by blowing the air onto a side surface of the sheet bundle supported by the sheet supporting unit, a velocity detection unit configured to detect actual velocity of a sheet fed by the sheet feed unit, a drive load detection unit configured to detect an actual drive load for feeding the sheet by the sheet feed unit, and a controller configured to control the sheet feed unit and the air separation unit. In a case where the sheet is fed by the sheet feed unit, the controller is configured to control an operation of the air separation unit depending on the actual velocity of the sheet detected by the velocity detection unit and the actual drive load detected by the drive load detection unit.

Abstract: The image forming apparatus forms a test chart on an image bearing member, the test chart including a plurality of test images including a first test image of a first density and a second test image formed at a position different from a position of the first test image in a conveying direction of a recording medium, the second test image having a second density different from the first density. The image forming apparatus transfers the test chart to the recording medium with a transfer roller and controls the rotation velocity of the transfer roller when the recording medium passes through a transfer portion based on a result of reading the test chart on the recording medium with a reading unit.

Abstract: The image forming apparatus forms a test chart on an image bearing member, the test chart including a plurality of test images including a first test image of a first density and a second test image formed at a position different from a position of the first test image in a conveying direction of a recording medium, the second test image having a second density different from the first density. The image forming apparatus transfers the test chart to the recording medium with a transfer roller and controls the rotation velocity of the transfer roller when the recording medium passes through a transfer portion based on a result of reading the test chart on the recording medium with a reading unit.

Abstract: A sheet feeding device includes a feeding roller pair, a detecting portion, a first changing portion, a second changing portion, and a controller for controlling the first changing portion and the second changing portion. The controller starts a first feeding operation for feeding a sheet toward the obliquely feeding roller pair in a nipping state of the feeding roller pair and then starts a second feeding operation for feeding the sheet for abutting a side end of the sheet against the reference member in the nipping state of the obliquely feeding roller pair. The controller changes, after the first feeding operation is started and before the second feeding operation is started, a start timing of the second feeding operation on the basis of a detection result of a position of the side end of the sheet detected by the detecting portion.

Abstract: An image forming apparatus includes a rotatable image bearing member, a rotatable transfer member, a first driving source to drive the image bearing member, a second driving source to drive the transfer member, and a control portion. Based on a toner amount per unit area of the toner image transferred to each of a plurality of first divided regions on a plane of a recording material in a feeding direction, the control portion controls a driving speed of the transfer member while each of the plurality of the first divided regions passes through a transfer portion. The control portion acquires an index value correlating with a toner amount of the toner image transferred to each of a plurality of second divided regions of each first divided region in a widthwise direction, and controls the driving speed based on the index value while the first divided region passes through the transfer portion.

Abstract: The image forming apparatus forms a test chart on an image bearing member, the test chart including a plurality of test images including a first test image of a first density and a second test image formed at a position different from a position of the first test image in a conveying direction of a recording medium, the second test image having a second density different from the first density. The image forming apparatus transfers the test chart to the recording medium with a transfer roller and controls the rotation velocity of the transfer roller when the recording medium passes through a transfer portion based on a result of reading the test chart on the recording medium with a reading unit.

Abstract: An image forming apparatus includes a rotatable image bearing member, a rotatable transfer member, a first driving source to drive the image bearing member, a second driving source to drive the transfer member, and a control. Based on a toner amount per unit area of the toner image transferred to each of a plurality of first divided regions of an in-plane of a recording material in a feeding direction, the control portion controls a driving speed of the transfer member while each of the plurality of the first divided regions passes through a transfer portion. The control portion acquires an index value correlating with a toner amount of the toner image transferred to each of a plurality of second divided regions of the first divided region in a widthwise direction, and controls the driving speed based on the index value while the first divided region passes through the transfer portion.

Abstract: An image forming apparatus includes an image forming unit configured to form an image on a sheet, a reversing unit configured to convey a sheet conveyed from the image forming unit in a first direction, stop the conveyance, and then convey the sheet in a second direction, which is opposite to the first direction, an image detection unit disposed to detect at least a portion of the image on the sheet stopped by the reversing unit, and a control unit configured to control the reversing unit and the image detection unit. The control unit is configured to detect the image on the sheet by the image detection unit while the sheet conveyance is stopped by the reversing unit.

Abstract: A sheet conveyance apparatus includes a conveyance roller, an abutment member including an abutment surface, an obliquely conveying roller configured to convey the sheet such that the side edge portion is moved toward the abutment surface, a sheet side-edge detection portion, and a controller. The controller is configured to control the conveyance force of the obliquely conveying roller at a first conveyance force until a predetermined time has elapsed, in an abutment operation in which the sheet is abutted against the abutment surface by the obliquely conveying roller, and control the conveyance force of the obliquely conveying roller at a second conveyance force larger than the first conveyance force if the predetermined time has elapsed and the position of the side edge portion of the sheet detected by the sheet side-edge detection portion is out of a predetermined range.

Abstract: A calculation system includes an obtaining unit and a calculation unit. The obtaining unit obtains information of a sheet. The calculation unit calculates an amount of change in length of the sheet in a conveyance direction of the sheet heated by a heating device to fix a toner image to the sheet based on the information of the sheet obtained by the obtaining unit and an elapsed time from a time when the sheet passes through the heating device.

Abstract: A sheet feeding apparatus includes a sheet supporting unit, a sheet feed unit, an air separation unit configured to separate the uppermost sheet by blowing the air onto a side surface of the sheet bundle supported by the sheet supporting unit, a velocity detection unit configured to detect actual velocity of a sheet fed by the sheet feed unit, a drive load detection unit configured to detect an actual drive load for feeding the sheet by the sheet feed unit, and a controller configured to control the sheet feed unit and the air separation unit. In a case where the sheet is fed by the sheet feed unit, the controller is configured to control an operation of the air separation unit depending on the actual velocity of the sheet detected by the velocity detection unit and the actual drive load detected by the drive load detection unit.

Abstract: A sheet conveyance apparatus includes a conveyance guide configured to guide a sheet along a conveyance center line extending in a conveyance direction, a reference member including an abutment surface, a conveyance unit configured to convey the sheet while abutting a first edge of the sheet against the abutment surface, a detection unit configured to detect a first angle formed between the first edge of the sheet and a second edge adjacent to the first edge, a moving unit configured to move the reference member so as to change a second angle formed between the abutment surface and the conveyance center line, and a control unit configured to perform a movement process in which the moving unit moves the reference member such that, when the first angle is referred to as ?, the second angle becomes an absolute value of a difference 90 degrees minus ?.

Abstract: An image forming apparatus includes a control unit that controls a conveyance velocity of conveying a recording medium by a fixing unit, to form a loop in the recording medium between a transfer nip portion and a fixing nip portion, in which the control unit controls the conveyance velocity to decrease the loop when a rear end of the recording medium reaches a first position that is apart upstream, in the conveyance direction, from a conveying nip portion of a conveying unit, by a distance that corresponds to a circumference length of a pressure-applying rotating member multiplied by an integer.

Abstract: A sheet feeding device includes a feeding roller pair, a detecting portion, a first changing portion, a second changing portion, and a controller for controlling the first changing portion and the second changing portion. The controller starts a first feeding operation for feeding a sheet toward the obliquely feeding roller pair in a nipping state of the feeding roller pair and then starts a second feeding operation for feeding the sheet for abutting a side end of the sheet against the reference member in the nipping state of the obliquely feeding roller pair. The controller changes, after the first feeding operation is started and before the second feeding operation is started, a start timing of the second feeding operation on the basis of a detection result of a position of the side end of the sheet detected by the detecting portion.

Abstract: A sheet conveyance apparatus includes a conveyance roller, an abutment member including an abutment surface against which a side edge, in a width direction, of the sheet abuts, and configured to correct a skew of the sheet, an obliquely conveying roller configured to convey the sheet such as the side edge of the sheet is conveyed toward the abutment surface, a sheet side edge detection portion configured to detect a position of the side edge of the sheet, and a control unit configured to control that a conveyance force, in the width direction, by the obliquely conveying roller in response to a detection result of the sheet side edge detection portion becomes smaller than that in an abutment movement.

Abstract: An image forming apparatus includes a control unit that controls a conveyance velocity of conveying a recording medium by a fixing unit, to form a loop in the recording medium between a transfer nip portion and a fixing nip portion, in which the control unit controls the conveyance velocity to decrease the loop when a rear end of the recording medium reaches a first position that is apart upstream, in the conveyance direction, from a conveying nip portion of a conveying unit, by a distance that corresponds to a circumference length of a pressure-applying rotating member multiplied by an integer.

Abstract: A sheet feeding device includes a sheet accommodating portion for accommodating a sheet, a feeding roller for feeding the sheet by rotation thereof in a state in which the feeding roller contacts an uppermost sheet accommodated in the sheet accommodating portion, a detecting portion for detecting a surface property of the sheet accommodated in the sheet accommodating portion, a changing means for changing contact pressure of the feeding roller to the uppermost sheet, and a controller for controlling the changing means so as to change the contact pressure on the basis of a result of the surface property of the sheet detected by the detecting portion.