Image forming apparatus including sheet cassette and capable of providing stabilized conveying performance of sheet positioned in sheet cassette

An image forming apparatus comprising:

• a housing;
• a sheet cassette movable in a first direction between an internal position and an external position, the sheet cassette comprising:
• a sheet accommodating portion configured to accommodate therein a sheet, the sheet accommodating portion being positioned inside the housing in a state where the sheet cassette is at the internal position, the sheet accommodating portion being positioned outside the housing in a state where the sheet cassette is at the external position;
• and
• a first roller;
• a second roller contacting the first roller in the state where the sheet cassette is at the internal position and configured to convey the sheet positioned in the sheet cassette in cooperation with the first roller;
• a gear train comprising a gear rotatable together with the second roller;
• a pendulum gear movable between a meshing position where the pendulum gear is in meshing engagement with the gear train and a separated position where the pendulum gear is separated away from the gear train;
• and
• a stop member configured to be moved from a first position to a second position in a second direction crossing the first direction by being pressed by a part of the sheet cassette moving from the external position to the internal position, the stop member being at the first position in the state where the sheet cassette is at the external position, the stop member retaining the pendulum gear at the separated position in a state where the stop member is at the first position, the stop member allowing the pendulum gear to move from the separated position to the meshing position in a state where the stop member is at the second position;
• wherein, in the state where the sheet cassette is at the internal position and the stop member is at the second position, the stop member is out of contact with the part of the sheet cassette in the first direction but contacts the part of the sheet cassette in the second direction.