Patent ID: 6608643
Filing Date: 2003-08-19
Classification: G02B

Abstract:
An image forming apparatus, comprising:a photoreceptor; an imaging system that controllably scans a plurality of light beams across the photoreceptor to form an image on the photoreceptor and comprising at least one adjustable element; at least one gray level detector located adjacent to the photoreceptor, said at least gray level detector usable to detect a developed area of a test patch image formed on the photoreceptor using the imaging system, the test patch image containing a pattern of developed regions that is indicative of an amount of beam spacing error between the plurality of light beams; and a control system connected to the at least one gray level detector and the imaging system, the control system usable to determine at least one differential gray level value based on output signals from the at least one gray level detector when detecting the test patch image.