According to an embodiment, a paper-length detection device includes: a moving mechanism and an angle sensor. The moving mechanism supports a magnet. The moving mechanism causes a first regulatory member to move closer to or further from a second regulatory member in accordance with movement of the first regulatory member. The moving mechanism further causes the magnet to rotate in accordance with the movement of the first regulatory member closer to or further from the second regulatory member. The angle sensor faces the magnet and outputs a signal corresponding to an absolute angle with the magnet.

An image reading device includes: a transport unit configured to transport a medium; an emission unit configured to emit an ultrasonic wave in accordance with a driving voltage and a reception unit configured to receive the ultrasonic wave, the emission unit and the reception unit being disposed so that a transport path for the medium transported by the transport unit is interposed therebetween; a reading unit configured to read the medium; and a control unit configured to detect presence or absence of multi-feed of the medium on the basis of a signal received by the reception unit. The image reading device is configured to switch a posture into any of a first posture or a second posture. The first posture is a posture in which the transport path is sloped relative to a mounting surface. The second posture is a posture in which an angle of the transport path relative to the mounting surface is smaller than that in the first posture. The control unit sets a first driving voltage as the driving voltage when the posture is the first posture, and sets a second driving voltage lower than the first driving voltage as the driving voltage when the posture is the second posture.

An image reading device includes: a transport unit configured to transport a medium; an emission unit configured to emit an ultrasonic wave in accordance with a driving voltage and a reception unit configured to receive the ultrasonic wave, the emission unit and the reception unit being disposed so that a transport path for the medium transported by the transport unit is interposed therebetween; a reading unit configured to read the medium; and a control unit configured to detect presence or absence of multi-feed of the medium on the basis of a signal received by the reception unit. The image reading device is configured to switch a posture into any of a first posture or a second posture. The first posture is a posture in which the transport path is sloped relative to a mounting surface. The second posture is a posture in which an angle of the transport path relative to the mounting surface is smaller than that in the first posture. The control unit sets a first driving voltage as the driving voltage when the posture is the first posture, and sets a second driving voltage lower than the first driving voltage as the driving voltage when the posture is the second posture.

A printer includes a lower tray and an upper tray provided above the lower tray. Each tray is provided with an edge guide that is displaceable according to the sheet size and that guides an edge of sheets. A guide sensor capable of detecting the distance to each edge guide is spaced from the edge guide by a gap in the displacement direction of the edge guide.

A printer includes a lower tray and an upper tray provided above the lower tray. Each tray is provided with an edge guide that is displaceable according to the sheet size and that guides an edge of sheets. A guide sensor capable of detecting the distance to each edge guide is spaced from the edge guide by a gap in the displacement direction of the edge guide.

A vacuum belt conveyor sequentially delivers sheet articles to a digital printer. The sheets are held in position by vacuum on the underside of the sheets through apertures in the belts and covered by the sheets. A plurality of independent plenums on the underside of the belt have chambers respectively communicating with rows of apertures extending along the belt. Vacuum is selectively applied from a manifold only to the plenum chambers that supply apertures that are covered by the sheets so that the ink from the printer will not be directed from its intended position on the sheet by vacuum from adjacent uncovered belt apertures. The sheets are fed to the conveyor in synchronism with the conveyor speed by a timed feeder so that the sheets are carried by the conveyor with a predetermined gap between the sheets and no belt apertures in the gap. A sensor counts the apertures in the belt and activates the feeder at predetermined time intervals.

A vacuum belt conveyor sequentially delivers sheet articles to a digital printer. The sheets are held in position by vacuum on the underside of the sheets through apertures in the belts and covered by the sheets. A plurality of independent plenums on the underside of the belt have chambers respectively communicating with rows of apertures extending along the belt. Vacuum is selectively applied from a manifold only to the plenum chambers that supply apertures that are covered by the sheets so that the ink from the printer will not be directed from its intended position on the sheet by vacuum from adjacent uncovered belt apertures. The sheets are fed to the conveyor in synchronism with the conveyor speed by a timed feeder so that the sheets are carried by the conveyor with a predetermined gap between the sheets and no belt apertures in the gap. A sensor counts the apertures in the belt and activates the feeder at predetermined time intervals.

In a saddle-stitching apparatus, when a sheet is transported to a center-folding unit, a folding blade moves from a retrieved position to a nip position between a pair of folding rollers. A forward end of the folding blade comes into contact with a fold of the sheet, so that the sheet is folded along the fold. When the sheet is attached to the nip position between the folding rollers, the folding rollers start rotating and then, the folding blade inserts the center-folded sheet between the folding rollers. After the center-fold finishing is completed, the rotations of the folding rollers stop in timing at which the folding blade is pulled out of the nip position between the folding rollers. When pulling the folding blade out of the nip position between the folding rollers, the rotations of the folding rollers restart.

In a saddle-stitching apparatus, when a sheet is transported to a center-folding unit, a folding blade moves from a retrieved position to a nip position between a pair of folding rollers. A forward end of the folding blade comes into contact with a fold of the sheet, so that the sheet is folded along the fold. When the sheet is attached to the nip position between the folding rollers, the folding rollers start rotating and then, the folding blade inserts the center-folded sheet between the folding rollers. After the center-fold finishing is completed, the rotations of the folding rollers stop in timing at which the folding blade is pulled out of the nip position between the folding rollers. When pulling the folding blade out of the nip position between the folding rollers, the rotations of the folding rollers restart.

A sheet feeding device includes a stacking tray, a feeding portion, a first restricting member which includes a first restricting surface and a first supporting portion, a second restricting member which includes a second restricting surface and a second supporting portion, and an interrelating portion. In a state in which the first restricting surface and the second restricting surface are brought closest to each other, a part of the first restricting portion is positioned on a second restricting surface side with respect to a center line of the stacking tray, and a part of the second restricting portion is positioned on a first restricting surface side with respect to the center line.