Apparatus and method for determining beam delays in a printing device

A method in an apparatus including a photosensitive surface, an integrated scan detector, a beam calibration controller, and a raster output scanner including a first optical emitter and at least one second optical emitter, the method comprising:

• scanning a first beam from the first optical emitter across the photosensitive surface;
• scanning a second beam from the at least one second optical emitter across the photosensitive surface;
• detecting, by the integrated scan detector, the first beam from the first optical emitter and the second beam from the at least one second optical emitter;
• producing a signal based on the beams detected from the raster output scanner by the integrated scan detector;
• determining, by the beam calibration controller, at least one beam delay between the first optical emitter and the at least one second optical emitter based on signals from the integrated scan detector;
• and
• delaying operation between the first optical emitter and the at least one second optical emitter based on the at least one beam delay.

An image forming apparatus comprising:

• a photosensitive surface;
• a raster output scanner optically coupled to the photosensitive surface, the raster output scanner including a first optical emitter configured to scan a first beam across the photosensitive surface to form an image on the photosensitive surface, the raster output scanner including a plurality of second optical emitters including at least one second optical emitter configured to scan a second beam across the photosensitive surface to form an image on the photosensitive surface;
• an integrated scan detector configured to detect the beams from the raster output scanner and configured to produce a signal based on the beams detected from the raster output scanner;
• and
• a beam calibration controller coupled to the integrated scan detector, the beam calibration controller configured to determine at least one beam delay between the first optical emitter and the at least one second optical emitter by operating the raster output scanner to illuminate the integrated scan detector with the first beam from the first optical emitter, receiving a first signal from the integrated scan detector corresponding to the integrated scan detector detecting the first beam, operating the raster output scanner to illuminate the integrated scan detector with the second beam from a second optical emitter of the plurality of second optical emitters, receiving a second signal from the integrated scan detector corresponding to the integrated scan detector detecting the second beam, and determining at least one beam delay for the second optical emitter based on a time between receiving the first signal from the integrated scan detector and receiving the second signal from the integrated scan detector and the beam calibration controller is configured to delay operation between the first optical emitter and the second optical emitter based on the at least one beam delay.