An image processing apparatus includes: a support surface configured to support a sheet, a sheet feeding roller configured to feed the sheet in a conveying direction, a separation member for separating the sheet one by one and positioned downstream of the sheet feeding roller in the conveying direction, and a regulating member displaceable between a first position where the regulating member abuts against a distal end of the sheet supported by the support surface to regulate passage of the sheet in the conveying direction between the sheet feeding roller and the separation member and a second position that is farther from a conveyance path than the first position and that allows passage of the sheet in the conveying direction. The regulating member has a wall surface that abuts against the distal end of the sheet and includes at least one protrusion on the wall surface.

In a sheet conveyor, a stopper piece of a sheet stopper temporarily stops a sheet supported on a sheet tray, and a pickup roller conveys the sheet from the sheet tray in a sheet conveying direction. A first sheet sensor disposed upstream of a registration roller and downstream of the stopper piece in the sheet conveying direction detects a leading edge of the sheet, and a second sheet sensor disposed downstream of the registration roller detects the leading edge of the sheet. A first contact member of the first sheet sensor receives the leading edge of the sheet. A second contact member of the second sheet sensor receives the leading edge of the sheet. The stopper piece, the first contact member, and the second contact member are offset from each other in a direction perpendicular to the sheet conveying direction and unaligned with each other in the sheet conveying direction.

A rotator control device includes drivers to drive rotators for sheet conveyance, respectively; and a processor including a selector to select, from the rotators, a pair of a first rotator subjected to rotation speed adjustment and a second rotator adjacent to the first rotator, and an acquisition unit to acquire a torque-related value representing a driving torque value of a driver to drive the second rotator or a value proportional thereto. The processor further includes a speed adjuster to adjust a rotation speed of the first rotator to approximate a variation in the torque-related value to zero. The selector selects a subsequent pair after adjustment of the rotation speed, designates the first rotator of the preceding pair as the second rotator of the subsequent pair, and selects, as the first rotator, a rotator adjacent to the first rotator of the preceding pair, opposite the second rotator of the preceding pair.

A document sheet transportation device includes a feeding portion which feeds a document sheet from a document sheet placement portion toward a document sheet transportation path. The feeding portion includes a holder, a feeding member, a supporting body supported by the holder, a rotatable stopper member having a contact end portion allowed to contact a front end of a document sheet, and a biasing member which applies a biasing force to the stopper member. The stopper member is allowed to change a position among a first position in which the contact end portion contacts the front end of the document sheet, a second position which allows feeding of the document sheet by the feeding member, and a third position which is rotated in the first rotating direction from the second position. The biasing member applies the biasing force to the stopper member in a reverse second rotating direction.

A medium feeding device including a medium mounting portion where media are mounted; a feeding roller that feeds the media from the medium mounting portion by contacting a bottommost sheet of the media mounted in the medium mounting portion, and rotating; a separator that separates a sheet of the media by nipping the sheet between the feeding roller and the separator; an abutting member that is provided above the feeding roller, is switchable between a closed posture that blocks a feeding path of the media upstream of the separator and an open posture that opens the feeding path, abuts against a leading edge of the media mounted in the medium mounting portion, and includes a friction surface at a position where the abutting member abuts against the leading edge; and a biasing member that biases the abutting member toward the closed posture.

A medium feeding device including a medium mounting portion where media are mounted; a feeding roller that feeds the media from the medium mounting portion by contacting a bottommost sheet of the media mounted in the medium mounting portion, and rotating; a separator that separates a sheet of the media by nipping the sheet between the feeding roller and the separator; an abutting member that is provided above the feeding roller, is switchable between a closed posture that blocks a feeding path of the media upstream of the separator and an open posture that opens the feeding path, abuts against a leading edge of the media mounted in the medium mounting portion, and includes a friction surface at a position where the abutting member abuts against the leading edge; and a biasing member that biases the abutting member toward the closed posture.

An image forming apparatus includes a print medium tray in which a print medium is loaded and a pickup roller which is configured to pick up the loaded print medium from the print medium tray. The pickup roller includes at least one first pickup block and at least one second pickup block configured to alternately come into contact with an upper portion of the loaded print medium. Using such a configuration, the pickup performance of the image forming apparatus may be improved.

An image forming apparatus includes a print medium tray in which a print medium is loaded and a pickup roller which is configured to pick up the loaded print medium from the print medium tray. The pickup roller includes at least one first pickup block and at least one second pickup block configured to alternately come into contact with an upper portion of the loaded print medium. Using such a configuration, the pickup performance of the image forming apparatus may be improved.

A sheet feeder includes: a feed roller; a transmission mechanism for transmitting a first drive force to the feed roller to rotate the feed roller in a feeding direction; a motor rotatable in a forward direction and in a reverse direction opposite the forward direction to generate a second drive force; a reverse roller rotatable in the feeding direction and in a counter-feeding direction opposite the feeding direction by the second drive force; and a driven part driven by the second drive force. The transmission mechanism transmits the first drive force to the feed roller to rotate the feed roller in the feeding direction in case that the reverse roller is rotated in the feeding direction; and the transmission mechanism transmits the first drive force to the feed roller to rotate the feed roller in the feeding direction in case that the reverse roller is rotated in the counter-feeding direction.

A sheet feeder includes: a feed roller; a transmission mechanism for transmitting a first drive force to the feed roller to rotate the feed roller in a feeding direction; a motor rotatable in a forward direction and in a reverse direction opposite the forward direction to generate a second drive force; a reverse roller rotatable in the feeding direction and in a counter-feeding direction opposite the feeding direction by the second drive force; and a driven part driven by the second drive force. The transmission mechanism transmits the first drive force to the feed roller to rotate the feed roller in the feeding direction in case that the reverse roller is rotated in the feeding direction; and the transmission mechanism transmits the first drive force to the feed roller to rotate the feed roller in the feeding direction in case that the reverse roller is rotated in the counter-feeding direction.