Opening and closing device

An opening and closing device for moving a movable member comprising:

• a drive gear connected to a power source;
• a driven gear geared with the drive gear;
• an immovable portion supporting the drive gear and the driven gear;
• a dynamic transmission mechanism, connected to the driven gear so that the driven gear and the dynamic transmission mechanism rotate together as a unit, the dynamic transmission mechanism transmitting a drive force of the power source from the driven gear to the movable member;
• and
• a shock absorbing member for applying a force to the movable member in accordance with a state of the movable member;
• wherein a direction of a rotational force affecting the driven gear via the dynamic transmission mechanism in accordance with a resultant force from a weight of the movable member and the shock absorbing member fluctuates;
• a friction member applied at least at one position between relatively movable facing surfaces of the immovable portion, the drive gear, the driven gear, and the dynamic power transmission mechanism.