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.

Disclosed is a paper feeding device comprising a storage surface for a stack of papers, with a leading edge, a trailing edge, and a first and a second side edge. The surface is adapted to be moved vertically. The device further comprises a vacuum feeder for feeding papers from their position on the storage surface and imparting on an uppermost sheet of paper a horizontal displacement, and a blower arrangement adapted to provide a curtain of air separating the uppermost sheet of paper from the rest of the stack of papers. The blower arrangement comprises a front blower unit having air openings with a first portion adapted to create first air cones and second portions adapted to create second air cones, wherein the first air cones are different from the second air cones.

A paper sheet processing apparatus including a plurality of transport units connected in a transport direction to which a paper sheet is transported, each of the plurality of transport units including a paper sheet detection sensor configured to detect presence/absence of the paper sheet, a transport mechanism configured to transport the paper sheet, driving means configured to drive the transport mechanism, and a controller unit configured to control the driving means, wherein the controller unit controls the driving means so that the paper sheet is transported by the transport mechanism based on a detection result of the paper sheet detection sensor.

According to one embodiment, a post-processing apparatus includes a first sensor, a second sensor, and a control unit. The first sensor detects an object in a predetermined area in which a predetermined post-process is performed on a sheet conveyed from an image forming apparatus. The second sensor detects an object at a position closer to an opening in the area than the position of the first sensor with respect to the opening through which the sheet passes when the post-processed sheet is discharged from the area. When the second sensor detects an object before the first sensor detects the object, the control unit performs a predetermined process for preventing the occurrence of a failure.

A sensor unit includes a first housing constituting a first conveying face of a sheet conveying passage, a second housing constituting a second conveying face arranged opposite the first conveying face with a predetermined gap, an edge detection sensor detecting a side edge along the sheet conveying direction, and a gap adjuster supporting the first housing movably in a direction in which the size of the gap increases. When, with the first housing arranged at the first position, a sheet with a thickness greater than a reference value passes through the sheet conveying passage, the first housing moves in the direction in which the size of the gap increases as the sheet enters the sheet conveying passage, to allow the passage of the sheet.

A reading device is configured to detect an edge position of a target object to be conveyed in a conveyance direction. The edge position is a position of an edge of the object in a width direction intersecting the conveyance direction. The reading device includes a sensor device, an adder, and an edge position detector. The sensor device includes a pixel array including a plurality of elements arranged in the width direction. The adder is configured to add detection signals output from the elements at respective positions in the width direction. The edge position detector is configured to detect the edge position on basis of a position at which an output of the adder changes to a value larger than a threshold. Each element is configured to output a detection signal based on a reception amount of light in one of different wavelength bands.

A method of testing a functional unit includes an optical sensor system (28) for detecting an optical signal from at least a part of a moving material web (14), a data processing system (36) for valuating the optical signals, and a display (38) displaying a state of the material web (14) and arranged in a sensitive range (30) of the sensor system (28).

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 method for detecting an edge of an object is carried out by means of a detection device (10), which has an emission region running along a first straight line and has a receiving region which runs along a second straight line, which is arranged in parallel to the first straight line. An emission subregion (11a-p) of the emission region is selected, which extends up to a first end of the emission region. Light is emitted from the emission subregion (11a-p) and a light signal of light reflected on the object is received in the receiving region. The emission subregion (11a-p) is then shifted along the first straight line in the direction of a second end of the emission region. Emitting, receiving and shifting are repeated until the emission subregion (11a-p) extends up to the second end at the start of the shifting step. A signal course is compiled from the received light signals, and the detection of the edge from the signal course is carried out.

A sheet conveying device, which is incorporated in an image forming apparatus, includes a first detector to detect an angle deviation of a recording medium to a sheet conveying direction, a second detector to detect a lateral shift of the recording medium to a width direction, a third detector to detect at least one of the angle deviation and the lateral shift after correction of the angle deviation detected by the first detector and the lateral shift detected by the second detector, and a rotary body to perform a primary movement by (1) rotating in the sheet conveying direction and returning to a reference position and by (2) moving in the width direction and returning to the reference position, and a secondary movement by performing at least one of (1) and (2) after the primary movement.