Sheet transport mechanism and electrophotographic image forming apparatus incorporating same

A sheet transport mechanism, comprising:

• a curved path configured to convey sheets in a sheet transport direction, the curved path including an upstream section having first and second branches meeting to form a downstream section having a sheet transport path, the sheet transport path being a single path on the curved path downstream of the first and second branches;
• a first sheet transport member including a first roller configured to feed and convey the sheets along the first branch in the sheet transport direction and a second roller configured to feed and convey the sheets along the second branch in the sheet transport direction;
• a second sheet transport member disposed downstream along the transport path to advance the sheets in the sheet transport direction;
• a contact member disposed on a first sidewall of the sheet transport path to contact sheets advancing downstream from the first and second branches, the contact member configured to movably rotate between a first position and a second position, the contact member maintaining the first position when not in contact with the sheets, the contact member including,
• a first contact portion, configured to retreat from the sheet transport path as the contact member rotates toward the second position when a leading edge of one of the sheets makes contact with the first contact portion as the sheets move in the sheet transport direction,
• a second contact portion connected to the first contact portion, the second contact portion configured to avoid the sheet transport path when the contact member is in the first position, and enter the sheet transport path only when the contact member rotates toward the second position to advance the sheets, and
• a feeler connected to at least one of the first contact portion and the second contact portion;
• and
• a detector to detect a change in position of the feeler as the contact member rotates between the first position and the second position, wherein
• the contact member is disposed at a position further recessed from the sheet transport path than the downstream section of the sheet transport path, and
• the sheet transport mechanism includes a point of rotation disposed upstream from the first contact portion and downstream from the second contact portion in the sheet transport direction about which the first contact portion and the second contact portion rotate.