Door opening and closing mechanism with dual pivot axis for a door

A door opening and closing mechanism fitted on a door that closes and opens an opening formed in a body of an apparatus by being brought into and out of contact with a rim of the opening, comprising:

• cam mechanisms that permit the door to engage with and disengage from the body at either one of right and left sides of the door, each of the cam mechanisms being movable between a first lock position and a second lock position, the cam mechanisms, each being disposed at a respective one of said sides and including:
• a groove cam guided by a rotating member in a direction generally perpendicular to a longitudinal axis of the rotating member;
• a lock outer cam having a slide surface;
• and
• a slide outer cam,
• wherein, when the door is closed, the cam mechanisms at both of said sides are kept in the first lock position and, when the door is opened at one of said sides, the other side of the door slides obliquely in a rearward direction toward the body of the apparatus and thereby causes the cam mechanism at the other side to be brought into the second lock position so as to be rotatably locked in the second lock position which allows the door to pivot about the cam mechanism at the other side of the door, and
• wherein, when the door is opened at said one side, at the other side, a vertex of the slide outer cam and a vertex of the lock outer cam are displaced from each other in a radial direction with respect to the rotating member, a distance, as much as at least 0.2% of a maximum distance between the groove cams.