A sheet conveying device, which is included in an image forming apparatus, includes a pair of rollers configured to convey a sheet in a sheet conveyance passage, a detector configured to optically detect an attitude of the sheet, one of a rotation device to rotate the pair of rollers in a direction parallel to a plane of the sheet and a moving device to move the pair of rollers in a width direction, and a controller configured to correct the attitude of the pair of rollers at a time interval, based on a detection result obtained by the detector. The controller performs the correcting operation by setting, according to reflectance of the sheet, at least one of a light emission time of the detector, the time interval of the correcting operation, light emission intensity of the detector and a conveying speed of the sheet.

A sheet conveying device, which is included in an image forming apparatus and a post processing device, includes a position detector configured to detect a position of a sheet, a sheet conveying body, a fixed body, a movable body configured to move, relative to the fixing body, between a first position and a second position different from the first position, and an index mounted on the fixed body. The sheet conveying device further includes a data storing device, a conveyance positional deviation calculator configured to calculate a positional deviation amount of the sheet to the reference sheet conveyance position, a detected positional deviation calculator configured to calculate a positional deviation amount of the position detector to the index based on a result of the position detector, and a reference position detector configured to correct the reference sheet conveyance position based on a result of the detected positional deviation calculator.

A label winding device is for receiving a medium including a label liner and a label member that is removably attached to the label liner and has at least one label portion and a waste portion, separating the waste portion from the label liner at a waste separation portion, and winding the at least one label portion with the label liner. The label winding device includes: a waste winder for winding the separated waste portion; a label winder for winding the at least one label portion with the label liner without the separated waste portion; a waste guide for guiding the separated waste portion to the waste winder; a support for rotatably supporting the waste guide; a sensor for detecting a rotational speed of the waste guide; and a waste break detector for detecting break of the waste portion on a basis of the detection by the sensor.

A sheet conveying device, which is included in an image forming apparatus and a post processing device, includes multiple position detectors and a position corrector. The multiple position detectors are aligned along a sheet conveying direction and configured to detect a side end of a sheet. The position corrector is configured to convey the sheet and correct a position of the sheet based on a positional deviation amount of the sheet, obtained by a detection result of the multiple position detectors. The positional deviation amount of the sheet is obtained by an extreme downstream position detector in the sheet conveying direction, of the multiple position detectors. A position of a subsequent sheet is corrected based on a sum of the positional deviation amount of the sheet and a positional deviation amount of the subsequent sheet.

A sheet conveying device, which is included in an image forming apparatus and a post processing device, includes a position detector configured to detect a position of a sheet, a sheet conveying body, a fixed body, a movable body configured to move, relative to the fixing body, between a first position and a second position different from the first position, and an index mounted on the fixed body. The sheet conveying device further includes a data storing device, a conveyance positional deviation calculator configured to calculate a positional deviation amount of the sheet to the reference sheet conveyance position, a detected positional deviation calculator configured to calculate a positional deviation amount of the position detector to the index based on a result of the position detector, and a reference position detector configured to correct the reference sheet conveyance position based on a result of the detected positional deviation calculator.

A post-processing apparatus includes a discharge tray, a sheet conveyor configured to convey a sheet onto the discharge tray, a drive unit configured to drive the sheet conveyor, a sensor configured to detect a position of the sheet discharged onto the discharge tray, and a control unit configured to determine a parameter to control the drive unit based on an output of the sensor, and to control the drive unit based on the determined parameter.

A sheet stacker includes a lifting mechanism, a tray, a conveyor, processing circuitry, an upper-limit sensor, a lift pause sensor, a lower-limit sensor, and a lowering pause sensor. The tray stacks multiple sheets. The conveyor above the tray conveys a sheet. The processing circuitry controls, via the lifting mechanism, a height position of the tray. The upper-limit sensor detects that an uppermost sheet of the sheets has reached an upper-limit position. The lift pause sensor detects that the uppermost sheet has reached a lift pause position lower than the upper-limit position. The lower-limit sensor detects that the tray has reached a lower-limit position. The lowering pause sensor detects that the tray has reached a lowering pause position higher than the lower-limit position. The upper-limit sensor, the lift pause sensor, the lower-limit sensor, and the lowering pause sensor are disposed in a space in which the tray is lifted and lowered.

A sheet conveying device, which is included in an image forming apparatus, includes a drive device, a pair of sheet holding rollers to convey a sheet in a sheet conveying direction, a gate to which a leading end of the sheet contacts, a first detector disposed upstream from the pair of sheet holding rollers to detect a position of the sheet and a second detector disposed downstream from the pair of sheet holding rollers to detect a position of the sheet. The pair of sheet holding rollers performs a primary correction to detect and correct a lateral displacement amount of the sheet by moving the pair of sheet holding rollers while holding the sheet, and then performs a secondary correction to detect and correct at least one of a subsequent lateral displacement of the sheet and an angular displacement of the sheet.

A sheet ejection device includes: a paper ejection chain (22b) for conveying paper (W); a first pile (26) or a second pile (26b) having loading plates (27a or 27b) arranged in a multistage manner and used for loading the paper ejected from the paper ejection chain; a first beam sensor (62a or 62b), a second beam sensor (63a or 63b), and a third beam sensor (64a or 64b) for detecting an intrusion into the first pile or the second pile. The sheet ejection device further comprises: a plate upper-limit position detection sensor (58a or 58b) for detecting that the loading plate has been positioned at a plate upper-limit position (L2); and a control device (50) for, based on the detection signal of the plate upper-limit position detection sensor, neglecting (disabling) a command for stopping a driving device (printing machine), the command is issued by the first to third beam sensors.

In a case where a skew of a document being conveyed is detected by a detection unit, an image reading apparatus notifies that documents having different sheet widths may be included in documents stacked on a stacking unit.