A sheet feeding device includes a first feeding roller pair, an upstream feeding roller pair, a downstream feeding roller pair, a second feeding roller pair, a first detecting portion, a second detecting portion, a third detecting portion, and a controller. The controller calculates a sheet feeding speed on the basis of a first time and a first distance. The controller calculates a length of the sheet with respect to the sheet feeding direction on the basis of the sheet feeding speed, a second time, and a second distance. The controller controls a sheet feeding timing by the second feeding roller pair on the basis of information of the length of the sheet.

A sheet stacker includes a housing, a fence, a first distance measurement sensor, and a second distance measurement sensor. The fence is movable in a fence moving direction on the housing and is configured to regulate a position of an end of a sheet. The first distance measurement sensor is configured to measure a distance between the fence and a first portion of the housing, the first portion being on one side of the housing with respect to the fence in the fence moving direction. The second distance measurement sensor is configured to measure a distance between the fence and a second portion of the housing, the second portion being on another side of the housing with respect to the fence in the fence moving direction.

An image reading apparatus includes a feeding roller that includes a first roller and a second roller provided at an interval in a width direction intersecting a medium feeding direction, and feeds a sheet from a placing section; and a skew detection section that detects skew of the sheet fed from the feeding roller. Skew is corrected by giving a difference between a rotation speed of the first roller and a rotation speed of the second roller with respect to at least one of the relevant sheet detected by the skew detection section and subsequent sheets fed following the relevant sheet based on a skew amount in the sheet.

A sensor (10) is used for detecting at least one edge of at least one product web (1) running in a run direction (2). The sensor (10) has active elements (11), which are arranged adjacent to one another and are formed by transmitters (12) and receivers (13). In this case, the transmitters (12) can emit waves (14) which are received by the receivers (13). The product web (1) is provided for influencing the waves (14) in the radiation path between the transmitters (12) and receivers (13). In this case, a first (21, 31) and second (22, 32) of the active elements (11) are adjacent and have a mutual first spacing (41). The second (22, 32) and a third (23, 33) of the active elements (11) are also adjacent to one another and have a second spacing (42), which corresponds to at least 1.2 times the first spacing (41).

An image recording apparatus including: a recording unit; an accommodation part configured to accommodate therein a plurality of recording media including first and second recording medium and having a support surface on which the plurality of the recording media is supported; a conveying path; a feeder roller contacting the recording medium in the accommodation part from above; a reversing path; a recording medium detection unit located above the support surface and between the feeder roller and a downstream end of the support surface in the conveying direction; and a controller configured to control the feeder roller so as to feed the second recording medium in a manner that a front end portion of the second recording medium overlaps a rear end portion of the first recording medium, when the recording medium detection unit detects the rear end portion of the first recording medium fed by the feeder roller.

An image reading apparatus includes a feeding roller that includes a first roller and a second roller provided at an interval in a width direction intersecting a medium feeding direction, and feeds a sheet from a placing section; and a skew detection section that detects skew of the sheet fed from the feeding roller. Skew is corrected by giving a difference between a rotation speed of the first roller and a rotation speed of the second roller with respect to at least one of the relevant sheet detected by the skew detection section and subsequent sheets fed following the relevant sheet based on a skew amount in the sheet.

A multi-feed detection device includes a transmission circuit substrate to which an ultrasonic transmitter transmitting an ultrasonic wave is installed, and an ultrasonic receiver receiving the ultrasonic wave. The ultrasonic transmitter has arrayed ultrasonic transmission elements and transmits ultrasonic waves with different phases from the ultrasonic transmission elements to transmit the ultrasonic waves in a direction diagonally intersecting a thickness direction of the transmission circuit substrate.

An image forming apparatus comprises a plurality of sheet detection units, provided at different positions along a sheet width direction, configured to detect the sheet conveyed on a conveyance path. A controller determines, by using the plurality of sheet detection units, a presence or absence of a sheet being conveyed in each of a plurality of regions sectioned in the sheet width direction, and determines, based on input image data, a presence or absence of an image to be formed in each of the plurality of regions. The controller further determines, based on the above determination results, whether or not the image to be formed on the sheet being conveyed is to be formed with a deviation from the sheet, and controls an image forming operation in accordance with this determination result.

A pick attempt of a media sheet from a media tray is initiated by rotating a pick roller a number of rotations that is set to greater than one in response to the sheet having been designated as a special media sheet type and that is set to one in response to the sheet not having been so designated. In response to a pick sensor detecting the sheet after the pick attempt has been attempted, a turn roller is rotated to advance the sheet to a print engine, and while the turn roller is rotating, the pick roller is rotated to assist advancement of the media sheet. A controller manages per-sheet and per-tray pick attempt counters while the sheet is individually attempted to be picked and advanced, using the counters to determine whether to initiate another pick attempt of the sheet when a current pick attempt has failed.

A multi-feed detection device includes a transmission circuit substrate on which an ultrasonic transmitter transmitting an ultrasonic wave is installed, and an ultrasonic receiver receiving the ultrasonic wave. The ultrasonic transmitter transmits the ultrasonic wave in a direction intersecting a thickness direction of the transmission circuit substrate and at least one of the ultrasonic transmitter and the ultrasonic receiver has a plurality of ultrasonic elements.