Gear, sheet conveyance device, and image forming apparatus

An image forming apparatus, comprising:

• a rotary shaft configured to include an engaged portion having a concave-shape;
• a conveyance roller configured to rotate around the rotary shaft and to convey a sheet;
• a driving source configured to drive the conveyance roller;
• a gear configured to rotate integrally with the rotary shaft and to transmit a driving force from the driving source to the conveyance roller;
• and
• an image forming unit configured to form an image on the sheet conveyed by the conveyance roller,
• wherein the gear includes:
• a tooth portion configured to engage with another gear,
• a wall surface configured to form an insertion hole into which the rotary shaft is inserted,
• a deformable portion configured to have a cantilever shape at least partially provided in an area provided with the tooth portion in a rotation axis direction of the gear, configured to form the insertion hole together with the wall surface, and configured to be elastically deformed by being pressed by the rotary shaft when the rotary shaft is inserted into the insertion hole,
• an engaging part configured to protrude from the deformable portion toward a rotation center of the gear, to engage with the engaged portion of the rotary shaft when the rotary shaft is inserted while elastically deforming the deformable portion, and to prevent the rotary shaft from falling off from the insertion hole, and
• a pressing part configured to protrude from the wall surface toward the rotation center of the gear, configured to be elastically deformed by being pressed by the rotary shaft when the rotary shaft is inserted into the insertion hole, and configured to press the rotary shaft toward the wall surface on a side opposite to the deformable portion in a state where the gear is attached to the rotary shaft.

A gear configured to be attached to a rotary shaft configured to include an engaged portion having a concave-shape, configured to rotate integrally with the rotary shaft, and configured to transmit a driving force from a driving source to a conveyance roller configured to convey a sheet, the gear comprising:

• a tooth portion configured to engage with another gear,
• a wall surface configured to form an insertion hole into which the rotary shaft is inserted,
• a deformable portion configured to have a cantilever shape at least partially provided in an area provided with the tooth portion in a rotation axis direction of the gear, configured to form the insertion hole together with the wall surface, and configured to be elastically deformed by being pressed by the rotary shaft when the rotary shaft is inserted into the insertion hole,
• an engaging part configured to protrude from the deformable portion toward a rotation center of the gear, to engage with the engaged portion of the rotary shaft when the rotary shaft is inserted while elastically deforming the deformable portion, and to prevent the rotary shaft from falling off from the insertion hole, and
• a pressing part configured to protrude from the wall surface toward the rotation center of the gear, configured to be elastically deformed by being pressed by the rotary shaft when the rotary shaft is inserted into the insertion hole, and configured to press the rotary shaft toward the wall surface on a side opposite to the deformable portion in a state where the gear is attached to the rotary shaft.