Patent ID: 8439357

Claim:
A paper transport device comprising: a transport section that transports paper to a reversal position in a first direction on a first transport path, and reverses a transport direction to a second direction that is a direction opposite to the first direction at the reversal position, to transport the paper onto a second transport path that branches from the first transport path; and a detecting section that detects that the paper is transported in the first direction, and has arrived at the reversal position, wherein the detecting section includes a first member that is arranged closer to the reversal position side than a branch point on the first transport path branched to the second transport path, and changes posture thereof among a first posture free of the contact with paper, a second posture where the first member comes into contact with the paper transported in the first direction and has rotated in the first direction from the first posture, and a third posture where the first member comes into contact with the paper transported in the second direction and has rotated in the second direction from the first posture, after the paper has passed in the first direction, a second member that changes posture thereof between a fourth posture and a fifth posture by rotation, a detector that (i) detects whether the second member is in the fourth posture or in the fifth posture, and (ii) keeps detecting the second member even if the first member rotates toward the third posture from the first posture, and a joint member that couples the first member and the second member together, allows the second member to be in the fourth posture when the first member is in the first posture, rotates the second member to the fifth posture when a movement in which the first member rotates toward the second posture from the first posture is transmitted to the second member and the first member has rotated to the second posture, and does not transmit a movement in which the first member rotates toward the third posture from the first posture, to the second member, and keeps the second member in the fourth posture.