Patent ID: 8339436

Claim:
An exposure unit containment mechanism comprising: an exposure unit that performs exposure in accordance with image data; and a frame that defines a space having an opening and containing the exposure unit inserted therein through the opening, wherein the exposure unit includes: first protrusions provided at a position spaced apart from a center of gravity of the exposure unit in a direction of insertion of the exposure unit into the space, such that the first protrusions protrude left and right with respect to the direction of insertion; a second protrusion that protrudes in a direction having a downward component; and third protrusions provided at a position spaced apart from the first protrusions and the second protrusion in a direction opposite to the direction of insertion, such that the third protrusions protrude in the left and right directions, and the frame includes: a guide member that contacts the first protrusions from above to limit movement of the first protrusions in an upward direction and guide the insertion of the exposure unit; a first limiting member that, when the exposure unit is guided by the guide member into the space, contacts the second protrusion from the left and from the right to limit left and right movement of the second protrusion; a second limiting member that, in a state where the movement of the second protrusion is limited by the first limiting member, contacts the first protrusions from underneath to limit downward movement of the first protrusions; a first pressing member that presses the first protrusions from above when the first protrusions are in contact with the second limiting member; a supporting member that supports the third protrusions from underneath; a third limiting member that, in a state where the first protrusions are pressed by the first pressing member, contacts the third protrusions in the direction opposite to the direction of insertion to limit movement of the third protrusions in the direction of insertion; and a second pressing member that presses the third protrusions, whose movement in the direction of insertion is limited by the third limiting member, against the third limiting member and against the supporting member.