Patent ID: 7267217

Claim:
An apparatus for conveying work sequentially passed from a first position and second position to at least a specific position, comprising: a first detector that detects if the conveyed work is or is not present at the first position; a second detector that detects if the conveyed work that has passed or is passing the first position is or is not present at the second position; a first calculator that calculates a first distance travelled by the conveyed work after the conveyed work is known from a detection result of the first detector to have passed the first position; a second calculator that calculates a second distance travelled by the conveyed work after the conveyed work is known from a detection result of the second detector to have passed the second position; and an evaluator that determines, after the presence of the conveyed work is no longer detected at the second position, if the conveyed work was or was not removed when the conveyed work was present at least at the second position based on the calculated first travelled distance and the calculated second travelled distance.