A sheet feeder includes a separation roller, a retard roller, and a return latch. The separation roller rotates in a forward direction to separate a sheet and transport the separated sheet in a sheet transport direction. The retard roller forms, together with the separation roller, a nip point and rotates in a reverse direction to return a sheet in a direction opposite to the sheet transport direction. The return latch moves from a retracted position to a protruding position to return a sheet remaining after separation by the separation roller to a position upstream of the nip point in the sheet transport direction. The return latch, when at the retracted position, is retracted from a sheet transport path and, when at the protruding position, protrudes to the sheet transport path.

A conveyance rotating body is rotatably supported by a support member. A second rotational axis at a rotation center of a driven transmission member is disposed at a position different from a position of a first rotational axis. When a feeding unit is attached to a sheet feeding apparatus, a drive transmission member and the driven transmission member engage with each other. When a driving force is transmitted from the drive transmission member to the driven transmission member, the feeding unit receives a force in an attachment direction of the feeding unit and is positioned with respect to the sheet feeding apparatus.

A sheet conveyance apparatus includes a cover unit, a base unit, a roller unit configured to be detachable from the cover unit, and comprising a roller configured to convey the sheet along a conveyance path and a holder comprising an arm portion configured to extend in a width direction orthogonal to a sheet conveyance direction, a cam configured to swing the holder by rotating, and a cover member configured to be openable and closable with respect to the cover unit and configured to cover at least a portion of the arm portion against the conveyance path in a closed state, the cover member being opened by being pressed by the arm portion in a case where the roller unit is detached from the cover unit.

An image recording device having a recording unit to record an image on a sheet is provided. The image recording unit includes a feed guide defining a first conveying path; an arm disposed between the recording unit and the tray, the arm having a feed roller rotatably disposed at a free end and configured to feed the sheet in the tray to the first conveying path. The arm pivots between a first arm position, and a second arm position. The return guide pivots between a first return guide position, and a second return guide position. A space occupied by the return guide in the first return guide position overlaps a space occupied by the arm in the second arm position. The return guide is in the second return guide position when the arm is in the second arm position which is retracted from an insertion space occupied by the tray.

A sheet conveyance apparatus includes a cover unit, a base unit, a roller unit configured to be detachable from the cover unit, and comprising a roller configured to convey the sheet along a conveyance path and a holder comprising an arm portion configured to extend in a width direction orthogonal to a sheet conveyance direction, a cam configured to swing the holder by rotating, and a cover member configured to be openable and closable with respect to the cover unit and configured to cover at least a portion of the arm portion against the conveyance path in a closed state, the cover member being opened by being pressed by the arm portion in a case where the roller unit is detached from the cover unit.

A sheet feeding apparatus includes a sheet accommodating unit, a sheet feeding unit, a first lifting portion, a second lifting portion, and a linear member configured to liftably support the first lifting portion and the second lifting portion, and stretched between the first lifting portion and the second lifting portion on a lower side of the stacking surface. In addition, a first winding unit, a second winding unit, and an adjustment member adjust both a first distance of the linear member between the first winding unit and the first lifting portion and a second distance of the linear member between the second winding unit and the second lifting portion.

A sheet feeding device includes a sheet accommodating portion mounted in a main assembly. With respect to a crossing direction perpendicularly crossing a pulling-out direction of the sheet accommodating portion from the main assembly as viewed in a direction of gravitation, the main assembly is provided with a positioning portion. A member-to-be-engaged is provided in one of the main assembly and the sheet accommodating portion. An engaging member is provided in the other of the main assembly and the sheet accommodating portion. The engaging member is elastically deformed when the sheet accommodating portion is pulled out in the pulling-out direction from a mounting position. The engaging member is provided swingably in the other one of the main assembly and the sheet accommodating portion so as to be capable of changing a position thereof with respect to the crossing direction.

An image forming apparatus includes a main body housing, an openable/closable part, a sheet feeding tray, an image forming device, a sheet feeding roller, a first coupling, a drive gear, a second coupling, a biasing member, and a link mechanism. The first coupling is provided in the sheet feeding roller. The second coupling is provided coaxially with the drive gear, rotatable following the drive gear, slidable relative to the drive gear in an axial direction and capable of fitting to the first coupling. The biasing member biases the second coupling to the first coupling to connect the second coupling to the first coupling. The link mechanism disconnects the second coupling from the first coupling against a biasing force of the biasing member so as to block a transmission of the drive force with an opening of the openable/closable part.

A holder supports a separation member. When a sheet cassette is attached to a main body portion, as the sheet cassette is moved in its attachment direction, a moving mechanism causes the holder to move from an initial position to an operation position. When the holder is at the initial position, the separation member is spaced from a feeding member and is able to pass below the feed-out member. When at the operation position, the holder presses the separation member against the feeding member. When the sheet cassette is attached to the main body portion, the moving mechanism causes the holder to move to the operation position after the separation member passes below the feed-out member. When the sheet cassette is drawn from the main body portion, the moving mechanism causes the holder to move to the initial position before the separation member reaches below the feed-out member.

A driving force transmission device includes a drive gear, a driven gear, which includes a gear portion and a partially toothless gear portion, rotates by the gear portion meshing with the drive gear, stops rotating in response to the partially toothless gear portion facing the drive gear, a first cam member and a second cam member which operate in conjunction with the driven gear, a first elastic member for urging the first cam member, a follower member to which urging force is applied by a second elastic member and which is moved by the second cam member, and a contact portion for coming into contact with the first cam member by urging force of the first elastic member. The first cam member includes a home cam surface for coming into contact with the contact portion so that rotation of the driven gear is limited.