Sheet conveyor and image forming apparatus

An image forming apparatus comprising:

• a sheet conveyor;
• and
• a print engine configured to form an image on a sheet fed from the sheet conveyor,
• the sheet conveyor comprising:
• a sheet tray configured to support the sheet;
• a motor;
• a drive shaft extending in an axial direction, the drive shaft having a tip end in the axial direction, the drive shaft having an end portion including the tip end, the drive shaft being rotatable in a first direction by receiving driving force of a forward rotation of the motor;
• a roller rotatable to feed the sheet supported by the sheet tray;
• and
• a hollow portion provided at the roller coaxially with the roller, the end portion of the drive shaft being inserted in the hollow portion,
• the hollow portion having an inner surface and a protrusion, the protrusion protruding radially inward from the inner surface and extending in the axial direction,
• the end portion of the drive shaft having a groove configured to fit to the protrusion,
• the groove having a first side surface and a second side surface, the second side surface facing the first side surface and located downstream of the first side surface in the first direction,
• the first side surface having a first contact surface configured to contact one side surface of the protrusion,
• the second side surface having a second contact surface and a guide surface, the second contact surface being smaller than the first contact surface, the second contact surface being configured to contact an other side surface of the protrusion, the guide surface being inclined away from the first contact surface in a direction from a tip-side end of the second contact surface toward the tip end of the drive shaft, the tip-side end of the second contact surface being an end facing toward the tip end of the drive shaft, the guide surface being configured to guide the protrusion to the groove.

A sheet conveyor comprising:

• a motor;
• a sheet tray configured to support sheets;
• a supply roller configured to supply the sheets supported by the sheet tray,
• a separation roller configured to separate the sheets supplied from the supply roller into one sheet at a time and to convey the one sheet, and
• a drive shaft extending in an axial direction, the drive shaft having a tip end in the axial direction, the drive shaft having an end portion including the tip end, the drive shaft being rotatable in a first direction by receiving driving force of a forward rotation of the motor, the drive shaft configured to transmit the driving force to the separation roller;
• the end portion of the drive shaft having a groove,
• the groove having a first side surface and a second side surface, the second side surface facing the first side surface and located downstream of the first side surface in the first direction,
• the first side surface having a first contact surface,
• the second side surface having a second contact surface and a guide surface, the second contact surface being smaller than the first contact surface, the guide surface being inclined away from the first contact surface in a direction from a tip-side end of the second contact surface toward the tip end of the drive shaft, the tip-side end of the second contact surface being an end facing toward the tip end of the drive shaft,
• the separation roller including a one-way clutch configured to:
• connect to the drive shaft when the drive shaft rotates in the first direction, and
• allow the roller to rotate in the first direction when the drive shaft is stopped.