| 摘要 |
<p>A method and apparatus is provided for registration of color images on a photoreceptor belt (14). Registration is accomplished by forming, in one embodiment, chevron-shaped registration marks (10,12) in non-image areas of the belt (14). A Raster Output Scanner (ROS) sweeps an output beam across the belt's surface. The beam is modulated in accordance with input video data to form successive color images. An unmodulated beam is also swept across the registration marks, each mark being successively swept by a plurality of beams. With each crossing of the legs of the chevron (10,12), two signals are generated by an associated sensor and stored in an averaging and extrapolation circuit. The multiple signals are compared and detection of the intersection is calculated by an extrapolation method. The averaging circuitry generates a registration signal which is used to enable an accurate start of page signal, to correct for skew and to adlust for errors and line-to-line spacing between lines in a color image frame (24). <IMAGE></p> |
