An image forming apparatus includes a feeder unit, a separating unit, a conveying unit disposed downstream of the separating unit in a sheet feeding direction, an image forming unit disposed downstream of the conveying unit in the sheet feeding direction, a drive unit, and a control unit. The feeder unit feeds a sheet. The separating unit separates sheets fed by the feeder unit one by one. The conveying unit conveys the sheet. The image forming unit forms, while the sheet is being conveyed, an image on the sheet. The drive unit drives the conveying unit. The control unit controls the drive unit. After the conveyed sheet reaches the image forming unit, the control unit reduces a conveyance speed of the sheet conveyed by the conveying unit.

An image forming apparatus includes a feeder unit, a separating unit, a conveying unit disposed downstream of the separating unit in a sheet feeding direction, an image forming unit disposed downstream of the conveying unit in the sheet feeding direction, a drive unit, and a control unit. The feeder unit feeds a sheet. The separating unit separates sheets fed by the feeder unit one by one. The conveying unit conveys the sheet. The image forming unit forms, while the sheet is being conveyed, an image on the sheet. The drive unit drives the conveying unit. The control unit controls the drive unit. After the conveyed sheet reaches the image forming unit, the control unit reduces a conveyance speed of the sheet conveyed by the conveying unit.

A sheet feeder including a tray, a feeder roller, a guide, a separator, a motor, a controller, and a sensor, is provided. The sheet feeder separates an object sheet from other sheets in the tray and feed the object sheet through the guide and the separator by rotation of the feeder roller. The controller determines a remaining volume of the sheets in the tray based on a signal from the sensor; generate a velocity profile so that the object sheet is fed at a lower velocity in an earlier first period than a velocity in a later second period; based on the determined remaining volume of the plurality of sheets, modify at least one of a length of the first period and the target velocity in the first period of the velocity profile; and after modification of the velocity profile, control the motor in compliance with the modified velocity profile.

A sheet feeder including a tray, a feeder roller, a guide, a separator, a motor, a controller, and a sensor, is provided. The sheet feeder separates an object sheet from other sheets in the tray and feed the object sheet through the guide and the separator by rotation of the feeder roller. The controller determines a remaining volume of the sheets in the tray based on a signal from the sensor; generate a velocity profile so that the object sheet is fed at a lower velocity in an earlier first period than a velocity in a later second period; based on the determined remaining volume of the plurality of sheets, modify at least one of a length of the first period and the target velocity in the first period of the velocity profile; and after modification of the velocity profile, control the motor in compliance with the modified velocity profile.

An image forming apparatus may comprise the following elements. A stacking unit in which a sheet is stacked. A conveyance unit conveys the sheet. A time-counting unit counts a conveyance time from when the conveyance unit starts to convey the sheet until the sheet arrives at a predetermined position on a conveyance path. A determination unit determines that over stacking has occurred, if the conveyance time of the sheet exceeds a first over stacking threshold value.

An image forming apparatus may comprise the following elements. A stacking unit in which a sheet is stacked. A conveyance unit conveys the sheet. A time-counting unit counts a conveyance time from when the conveyance unit starts to convey the sheet until the sheet arrives at a predetermined position on a conveyance path. A determination unit determines that over stacking has occurred, if the conveyance time of the sheet exceeds a first over stacking threshold value.

When a discharge count has exceeded a specified number of sheets, a sheet discharge device executes a process of moving down a discharge tray by a specified quantity and thereafter moving up the discharge tray until a top-surface detection part outputs a top-surface detection signal, while clocking a move-up time lasting from a move-up start of the discharge tray until output of the top-surface detection signal by the top-surface detection part. When the move-up time is equal to or less than a reference time, the sheet discharge device makes a next sheet discharged while the top-surface detection part outputs the top-surface detection signal; on the other hand, when the move-up time is more than the reference time, the sheet discharge device executes a correction process of moving down the discharge tray before making the next sheet discharged.

When a discharge count has exceeded a specified number of sheets, a sheet discharge device executes a process of moving down a discharge tray by a specified quantity and thereafter moving up the discharge tray until a top-surface detection part outputs a top-surface detection signal, while clocking a move-up time lasting from a move-up start of the discharge tray until output of the top-surface detection signal by the top-surface detection part. When the move-up time is equal to or less than a reference time, the sheet discharge device makes a next sheet discharged while the top-surface detection part outputs the top-surface detection signal; on the other hand, when the move-up time is more than the reference time, the sheet discharge device executes a correction process of moving down the discharge tray before making the next sheet discharged.

A sheet loading device is provided with a sheet ejection portion, a sheet loading portion, a first detection mechanism, a driving device, a second detection mechanism, and a control portion. The driving device drives the sheet loading portion to ascend/descend between an upper surface detection position and a reference position made to descend by a prescribed distance from the upper surface detection position. The second detection mechanism detects that the sheet loading portion is at the reference position. In a case where sheets of the same type are ejected continuously from the sheet ejection portion, the control portion controls beforehand the sheet loading portion to ascend from the reference position to the upper surface detection position and sets a loadable number of sheets of the sheet loading portion in accordance with an ascending time of the sheet loading portion.

A sheet loading device is provided with a sheet ejection portion, a sheet loading portion, a first detection mechanism, a driving device, a second detection mechanism, and a control portion. The driving device drives the sheet loading portion to ascend/descend between an upper surface detection position and a reference position made to descend by a prescribed distance from the upper surface detection position. The second detection mechanism detects that the sheet loading portion is at the reference position. In a case where sheets of the same type are ejected continuously from the sheet ejection portion, the control portion controls beforehand the sheet loading portion to ascend from the reference position to the upper surface detection position and sets a loadable number of sheets of the sheet loading portion in accordance with an ascending time of the sheet loading portion.