Patent ID: 8805022

Claim:
A velocity detection apparatus which detects a position of a moving object at a first timing and a second timing to detect a velocity of the moving object using a difference between the first timing and the second timing, the first timing being a timing at which an identifiable mark position of the moving object is detected by a first detector, the second timing being a timing at which the mark position is detected by a second detector, the velocity detection apparatus comprising: one light source configured to illuminate the moving object using divergent luminous flux; a first photo sensor that includes a first signal processor and a first detector configured to detect the mark position of the moving object based on light obtained by illuminating the moving object using the one light source; and a second photo sensor that includes a second signal processor and a second detector disposed at a position shifted in a moving direction of the moving object with respect to the first detector and is configured to detect the mark position of the moving object based on the light obtained by illuminating the moving object using the one light source, wherein a vertical projection position of the light source onto a plane, which is parallel to a main surface of the first detector or the second detector, is located between vertical projection positions of the first detector and the second detector onto the plane, and wherein the first photo sensor and the second photo sensor are disposed differently from each other when being projected onto the plane.