Sheet conveyance apparatus, image reading apparatus and image forming apparatus

An image reading apparatus comprising:

• an image reading unit configured to read an image on a sheet;
• and
• a sheet conveyance apparatus comprising:
• a conveyance roller configured to convey the sheet;
• a driving source configured to drive the conveyance roller;
• and
• a drive transmission mechanism configured to transmit a driving force from the driving source to the conveyance roller, the drive transmission mechanism comprising:
• a shaft;
• a first rotary member supported on the shaft and driven to rotate by the driving source;
• a second rotary member supported on the shaft and connected to the conveyance roller so as to rotate the conveyance roller;
• and
• a coupling member engaged with the first rotary member and rotated integrally with the first rotary member, the coupling member comprising a body portion positioned on a side opposite from the second rotary member in an axial direction of the shaft with respect to the first rotary member and a projected portion projected from the body portion and extending toward the second rotary member in the axial direction through the first rotary member, the coupling member being movable in the axial direction between a coupling position, at which the projected portion engages with the second rotary member such that the second rotary member rotates integrally with the first rotary member, and a release position, at which the projected portion is separated from the second rotary member such that a relative rotation of the second rotary member with respect to the first rotary member is permitted,
• wherein the first rotary member comprises an opening portion through which the projected portion of the coupling member is inserted, and
• the second rotary member comprises an engagement portion engaging with the projected portion projected from the first rotary member through the opening portion.

An image forming apparatus comprising:

• an image forming portion configured to form an image on a sheet;
• and
• a sheet conveyance apparatus comprising:
• a conveyance roller configured to convey the sheet;
• a driving source configured to drive the conveyance roller;
• and
• a drive transmission mechanism configured to transmit a driving force from the driving source to the conveyance roller, the drive transmission mechanism comprising:
• a shaft;
• a first rotary member supported on the shaft and driven to rotate by the driving source;
• a second rotary member supported on the shaft and connected to the conveyance roller so as to rotate the conveyance roller;
• and
• a coupling member engaged with the first rotary member and rotated integrally with the first rotary member, the coupling member comprising a body portion positioned on a side opposite from the second rotary member in an axial direction of the shaft with respect to the first rotary member and a projected portion projected from the body portion and extending toward the second rotary member in the axial direction through the first rotary member, the coupling member being movable in the axial direction between a coupling position, at which the projected portion engages with the second rotary member such that the second rotary member rotates integrally with the first rotary member, and a release position, at which the projected portion is separated from the second rotary member such that a relative rotation of the second rotary member with respect to the first rotary member is permitted,
• wherein the first rotary member comprises an opening portion through which the projected portion of the coupling member is inserted, and
• the second rotary member comprises an engagement portion engaging with the projected portion projected from the first rotary member through the opening portion.

A sheet conveyance apparatus comprising:

• a conveyance roller configured to convey a sheet;
• a driving source configured to drive the conveyance roller;
• and
• a drive transmission mechanism configured to transmit a driving force from the driving source to the conveyance roller, the drive transmission mechanism comprising:
• a shaft;
• a gear supported on the shaft and driven to rotate by the driving source;
• a pulley supported on the shaft and connected to the conveyance roller so as to rotate the conveyance roller;
• and
• an engagement claw engaged with the gear so as to rotate integrally with the gear, the engagement claw being movable in an axial direction of the shaft between a coupling position, at which the engagement claw engages with the pulley such that the pulley is rotated integrally with the gear, and a release position, at which the engagement claw is separated from the pulley such that a relative rotation of the pulley with respect to the gear is permitted.