A feeder includes: a mount board that moves vertically while allowing sheet-shaped media to be stacked thereon; a transport device that allows an uppermost one of the sheet-shaped media stacked on the mount board to be sucked by a suction portion to transport the uppermost sheet-shaped medium to a transporter and to feed the uppermost sheet-shaped medium to a destination; left and right edge air blowers that blow air to left and right edge portions, when viewed from an upstream side in a transportation direction, of upper ones of the sheet-shaped media stacked; and left and right detectors that are disposed on left and right sides of the suction portion at the same position in the transportation direction, and that individually detect downward or upward bend amounts of left and right edge portions of the uppermost sheet-shaped medium.

A conveyance device includes a conveyance roller, a registration roller, a sensor, a mode setting part, a storage, a conveyance state determination part and a drive control part. The mode setting part sets the mode to either a plain paper mode or a tab paper mode. The storage stores threshold information corresponding to the mode. The conveyance state determination part determines, when the plain paper mode is set, whether the conveyance state of the recording medium is a skew conveyance state or a tab paper conveyance state, based on the detection result of the sensor and the plain paper mode threshold information. The conveyance state determination part determines, when the tab paper mode is set, whether the conveyance state of the recording medium is the skew conveyance state or the tab paper conveyance state, based on the detection result of the sensor and the tab paper mode threshold information.

A sheet feeding device includes a sheet tray, a blower, a feeder, an illuminator, an imager, and circuitry. The sheet tray stacks sheets. The blower blows air to the sheets stacked on the sheet tray and floats an uppermost sheet of the sheets. The feeder feeds the uppermost sheet. The illuminator illuminates the uppermost sheet floating. The imager captures an image including the uppermost sheet illuminated by the illuminator. The circuitry adjusts an imaging condition based on the image captured by the imager.

A sheet feeder apparatus includes a width detector for a sheet placed on a sheet placement portion, a conveyor for conveying sheets while separating the sheets one by one, a first detector for detecting a sheet having a first width at a plurality of first positions, a second detector for detecting a sheet having a second width that is not detected by the first sheet detector at a plurality of second positions, and a controller for determining skewing of a sheet based on a result of the detection of the sheet performed by the first detector if the width of the sheet is the first width, and determining skewing of a sheet based on a result of the detection performed by the second detector if the width of the sheet is the second width.

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 medium feeding device includes a storage unit that stores media in a form of a sheet, a delivery unit that is disposed downstream in a medium delivery direction relative to the media stored in the storage unit and that delivers the media individually, a transfer unit that is disposed above the storage unit and that sticks by suction to each of the media stored in the storage unit and transfers the media to the delivery unit individually, and a fluffing unit that is disposed beside the media stored in the storage unit in a direction intersecting the medium delivery direction. The fluffing unit fluffs an upper-side region of the media in a state of being separated by blowing air toward a side of the media. The medium feeding device further includes plural position detection units that are arranged in a region that is on the delivery unit side relative to a position of a downstream end portion, in the medium delivery direction, of each of the media stored in the storage unit and that does not reach a contact portion where the delivery unit comes into contact with the media. The position detection units are arranged at an interval in a width direction of the media intersecting the medium delivery direction. The position detection units detect a position of the downstream end portion, in the medium delivery direction, of each of the media.

A sheet conveying device includes a sheet detection unit and a position adjusting mechanism. The position adjusting mechanism is disposed on a downstream side of the sheet detection unit in a sheet conveying direction in the sheet conveying path, includes an adjusting roller pair, and performs skew correction and positional displacement correction of a sheet, while conveying the sheet. The sheet conveying path includes a first conveying roller pair disposed on an upstream side of the position adjusting mechanism in the sheet conveying direction, and a curved part disposed between the adjusting roller pair and the first conveying roller pair, which curves in an S shape so as to be convex in a front and back side direction of the sheet alternately at different positions in the sheet conveying direction. The adjusting roller pair nips and conveys the sheet together with the first conveying roller pair.

A conveyance apparatus includes a separation unit configured to separate and convey a sheet, a detection unit configured to detect a floating of the sheet passing through the separation unit, and a control unit configured to stop separate conveyance by the separation unit if the detection unit detects the sheet for not less than a predetermined time and/or a predetermined count.

A conveyance apparatus includes a separation unit configured to separate and convey a sheet, a detection unit configured to detect a floating of the sheet passing through the separation unit, and a control unit configured to stop separate conveyance by the separation unit if the detection unit detects the sheet for not less than a predetermined time and/or a predetermined count.

An image forming apparatus includes a cassette that has a placement plate on which a sheet is set, a paper feed roller, a raising/lowering mechanism that raises and lowers the placement plate, a print unit, a sheet sensor, an upper limit sensor and a control unit. The control unit recognizes, based on an output of the sheet sensor, that the sheet supplied from a paper feed device reaches an installation position of the sheet sensor. The control unit detects, based on an output of the upper limit sensor, that the paper feed roller reaches a predetermined upper limit position or that the raising/lowering mechanism raises the placement plate such that the sheet reaches a feed position and uses the sheet sensor and the upper limit sensor so as to detect that the paper feed device encounters overload.