Patent ID: 8532557

Claim:
An attachment assist device to assist attachment of a retractable unit to a main body, the attachment assist device comprising: an engagement member provided in the retractable unit; a catch portion provided in the main body, to engage the engagement member when the retractable unit is set at a start position from which the retractable unit is drawn in an attachment direction into the main body against multiple resistive forces acting on the retractable unit while the retractable unit moves from the start position to a completion position, guide rails provided in the main body, to guide movement of the retractable unit; the catch portion engaging the engagement member at an engagement position disposed inside a rectangular area defined by two opposing corners respectively positioned at points of action of two of the multiple resistive forces acting on the retractable unit, except the resistive forces acting on the guide rails, on a projection plane on which the retractable unit is projected in the attachment direction; the drawing unit drawing the retractable unit to the drawing completion position in the main body when the engagement member engages the catch portion, a pivotable member to engage the engagement member, which enables the catch portion to rotate, the catch portion being formed in an end portion of the pivotable member; and an elastic member configured to be biased to cause the pivotable member to pivot in a direction in which the retractable unit is drawn into the main body when the catch portion engages the engagement member, the elastic member having a first end fixed to the main body and a second end opposite the first end, the second end fixed to the pivotable member.