A sheet conveyance apparatus includes a sheet supporting tray to support a sheet, a sheet conveyance unit to convey the sheet supported on the sheet supporting tray, a first detection sensor to detect the supported sheet at a first detection position, and a second detection sensor to detect the supported sheet at a second detection position farther from a center of the sheet supporting tray in a sheet width direction than the first detection position. In addition, a control unit controls the sheet conveyance unit in a first mode in a case where the first and second detection sensors detect the sheet, and controls the sheet conveyance unit in a second mode in which a sheet conveyance speed is slower than that of the first mode in a case where the first detection sensor detects the sheet and the second detection sensor detects no sheet.

A sheet conveyance apparatus includes a sheet supporting tray to support a sheet, a sheet conveyance unit to convey the sheet supported on the sheet supporting tray, a first detection sensor to detect the supported sheet at a first detection position, and a second detection sensor to detect the supported sheet at a second detection position farther from a center of the sheet supporting tray in a sheet width direction than the first detection position. In addition, a control unit controls the sheet conveyance unit in a first mode in a case where the first and second detection sensors detect the sheet, and controls the sheet conveyance unit in a second mode in which a sheet conveyance speed is slower than that of the first mode in a case where the first detection sensor detects the sheet and the second detection sensor detects no sheet.

A conveyance apparatus includes a bearing rotator, an entrance rotator, an exit rotator, a first driver circuit, a downstream conveyor, a second driver circuit, and a recording medium detector. The entrance rotator receives a recording medium at a first position. The downstream conveyor receives the medium at a second position. As a process of removing the medium, the first driver circuit starts rotation operation after the second driver circuit starts driving the downstream conveyor and rotates the rotators for not less than a period of time for the medium to be conveyed from the first position to the second position. The second driver circuit continues driving the downstream conveyor for not less than a period of time for the medium to be conveyed from the second position to a position at which the medium is detected after the rotation operation of the first driver circuit is stopped.

A conveyance apparatus includes a bearing rotator, an entrance rotator, an exit rotator, a first driver circuit, a downstream conveyor, a second driver circuit, and a recording medium detector. The entrance rotator receives a recording medium at a first position. The downstream conveyor receives the medium at a second position. As a process of removing the medium, the first driver circuit starts rotation operation after the second driver circuit starts driving the downstream conveyor and rotates the rotators for not less than a period of time for the medium to be conveyed from the first position to the second position. The second driver circuit continues driving the downstream conveyor for not less than a period of time for the medium to be conveyed from the second position to a position at which the medium is detected after the rotation operation of the first driver circuit is stopped.

A feeder of a sheet treating or a sheet processing machine comprises a sensor system, which sensor system, on a front side pointing in a direction of transport of the sheets to be fed or on the opposing, rear side of the pile of sheets to be fed, comprises one or more sensors, by the use of which sensors, a distance, with respect to at least two locations, which are spaced apart from one another transversely to the transport direction, at the relevant front or rear sides of the pile, can be ascertained. A method is provided for detecting or correcting sheets having deviated positions or dimensions in such a sheet feeder of a sheet treating or processing machine.

A feeder of a sheet treating or a sheet processing machine comprises a sensor system, which sensor system, on a front side pointing in a direction of transport of the sheets to be fed or on the opposing, rear side of the pile of sheets to be fed, comprises one or more sensors, by the use of which sensors, a distance, with respect to at least two locations, which are spaced apart from one another transversely to the transport direction, at the relevant front or rear sides of the pile, can be ascertained. A method is provided for detecting or correcting sheets having deviated positions or dimensions in such a sheet feeder of a sheet treating or processing machine.

An image forming device includes an image forming unit, a reading unit, a registration-less unit, and an engine control unit. The reading unit reads a sheet to be conveyed. The engine control unit moves the other end side of the registration-less unit to correct skew. The engine control unit obtains a deviation amount (first deviation amount) of the position of the sheet based on the correction, and changes a sheet conveyance speed from a first speed to a second speed when the sheet enters the registration-less unit. The engine control unit adjusts the timing to change from the first speed to the second speed based on the first deviation amount.

An image forming device includes an image forming unit, a reading unit, a registration-less unit, and an engine control unit. The reading unit reads a sheet to be conveyed. The engine control unit moves the other end side of the registration-less unit to correct skew. The engine control unit obtains a deviation amount (first deviation amount) of the position of the sheet based on the correction, and changes a sheet conveyance speed from a first speed to a second speed when the sheet enters the registration-less unit. The engine control unit adjusts the timing to change from the first speed to the second speed based on the first deviation amount.

A sheet feeding device includes a sheet stacking unit, a long sheet stacking unit, a first guide, a first detector, and a closing unit. The sheet stacking unit is movable up and down. Sheets are stacked on the sheet stacking unit. The long sheet stacking unit is detachably mounted on the sheet stacking unit. Long sheets are stacked on the long sheet stacking unit. The first guide is movable along a feeding direction through a groove. The first guide is deformable into a shape that does not interfere with the long sheet stacking unit. The first guide guides a rear end portion of the sheets in the feeding direction. The first detector is provided in the first guide. The first detector detects the sheets stacked on the sheet stacking unit. The closing unit is detachably attached to the groove in the sheet stacking unit. The closing unit closes the groove.

A sheet feeding device includes a sheet stacking unit, a long sheet stacking unit, a first guide, a first detector, and a closing unit. The sheet stacking unit is movable up and down. Sheets are stacked on the sheet stacking unit. The long sheet stacking unit is detachably mounted on the sheet stacking unit. Long sheets are stacked on the long sheet stacking unit. The first guide is movable along a feeding direction through a groove. The first guide is deformable into a shape that does not interfere with the long sheet stacking unit. The first guide guides a rear end portion of the sheets in the feeding direction. The first detector is provided in the first guide. The first detector detects the sheets stacked on the sheet stacking unit. The closing unit is detachably attached to the groove in the sheet stacking unit. The closing unit closes the groove.