A drive transmission device (6) includes a first drive train (62) and a second drive train (63). The first drive train (62) includes a first gear (621), a second gear (622), a rotary shaft (623), and one-way clutches (624). The second drive train (63) includes a third gear (631), a fourth gear (632), a rotary shaft (633), and an electromagnetic clutch (634). The third gear (631) engages the first gear (621) and the fourth gear (632) engages the second gear (622). A rotational speed of a pickup roller (12) is switched by switching on/off the electromagnetic clutch (634) to change a transmission path of driving force.

A feed device includes: a feed tray configured to accommodate a roll, in which a medium is rolled in a roll shape, rotatably; a housing configured to support the feed tray installable; and a pull-back mechanism configured to pull back the medium unrolled from the roll in a direction orthogonal to a rotation axis of the roll in conjunction with an outward movement of the feed tray from the housing in the direction orthogonal to the rotation axis of the roll.

In one example, a media feed system includes a pick arm that is adjustable at a pivot and operable to maintain a distance between a pick roller and a separation wall as the pick arm changes orientation. In another example, a media feed system may include a pick arm, a pick roller coupled to the pick arm, a pivot coupled to the pick arm, and a plate coupled to the pivot via a pin and slot interface. In that example, a slot of the pin and slot interface is to adjust position of the pivot and adjust orientation of the pick arm.

A document conveyance device includes a feed roller, a separation roller, a first motor for generating a first drive force for driving the separation roller, a planet gear, a drive gear, a second motor for generating a second drive force, and a position switching mechanism for switching a position of the planet gear from a first position in which the planet gear is separated from the drive gear and does not transmit the first drive force to the separation roller to a second position in which the planet gear engages with the drive gear and transmits the first drive force to the separation roller, based on the second drive force. The position switching mechanism includes a support member for supporting the planet gear, and a transfer mechanism for moving the support member so that the planet gear engages with the drive gear, based on the second drive force. The further movement of the planet gear is prevented after the planet gear engaged with the drive gear.

A document conveyance device includes a feed roller, a separation roller, a first motor for generating a first drive force for driving the separation roller, a planet gear, a drive gear, a second motor for generating a second drive force, and a position switching mechanism for switching a position of the planet gear from a first position in which the planet gear is separated from the drive gear and does not transmit the first drive force to the separation roller to a second position in which the planet gear engages with the drive gear and transmits the first drive force to the separation roller, based on the second drive force. The position switching mechanism includes a support member for supporting the planet gear, and a transfer mechanism for moving the support member so that the planet gear engages with the drive gear, based on the second drive force. The further movement of the planet gear is prevented after the planet gear engaged with the drive gear.

A sheet supplier, including: a tray including a sheet support surface; a sheet supply roller configured to supply an uppermost one of sheets; a rotational member configured to contact a lowermost one of the sheets; a presser configured to press the supply roller relative to the rotational member; and a supporter configured to support the rotational member by a contact portion such that the rotational member is rotated by a movement of the lowermost sheet and to limit a movement of the rotational member caused by a force of the lowermost sheet in a sheet supply direction; wherein, where static friction coefficients between the supply roller and the uppermost sheet, between the sheets on the support surface, between the rotational member and the lowermost sheet, and between the rotational member and the contact portion are respectively defined as 2, 3, and 4, the following expressions are satisfied: 1>4>2, 3>4.

A drive transmission device (6) includes a first drive train (62) and a second drive train (63). The first drive train (62) includes a first gear (621), a second gear (622), a rotary shaft (623), and one-way clutches (624). The second drive train (63) includes a third gear (631), a fourth gear (632), a rotary shaft (633), and an electromagnetic clutch (634). The third gear (631) engages the first gear (621) and the fourth gear (632) engages the second gear (622). A rotational speed of a pickup roller (12) is switched by switching on/off the electromagnetic clutch (634) to change a transmission path of driving force.

In one example, a media feed system includes a pick arm that is adjustable at a pivot and operable to maintain a distance between a pick roller and a separation wall as the pick arm changes orientation. In another example, a media feed system may include a pick arm, a pick roller coupled to the pick arm, a pivot coupled to the pick arm, and a plate coupled to the pivot via a pin and slot interface. In that example, a slot of the pin and slot interface is to adjust position of the pivot and adjust orientation of the pick arm.

A sheet supplier, including: a tray including a sheet support surface; a sheet supply roller configured to supply an uppermost one of sheets; a rotational member configured to contact a lowermost one of the sheets; a presser configured to press the supply roller relative to the rotational member; and a supporter configured to support the rotational member by a contact portion such that the rotational member is rotated by a movement of the lowermost sheet and to limit a movement of the rotational member caused by a force of the lowermost sheet in a sheet supply direction; wherein, where static friction coefficients between the supply roller and the uppermost sheet, between the sheets on the support surface, between the rotational member and the lowermost sheet, and between the rotational member and the contact portion are respectively defined as 2, 3, and 4, the following expressions are satisfied: 1>4>2, 3>4.

A sheet feeding apparatus capable of lifting a feed roller at low cost without increasing size thereof and an image forming apparatus including the same are proposed. A sheet fed from a rotary feed member is conveyed by a rotary conveyance member while being separated one by one by a rotary separation member being in contact with the rotary conveyance member. The rotary feed member is moved between a standby position above the sheet and an abutment position where the rotary feed member abuts with the sheet by a lifting portion. The lifting portion includes an actuation member moving a holding portion up and down and a drive member driving the actuation member. The actuation member is disposed on a second shaft, which is configured to rotate the rotary separation member.