Patent ID: 7116347
Filing Date: 2006-10-03
Classification: G02B,G06K,H04N

Abstract:
1. An optical scanning device comprising: a light source emitting a light beam based on a pixel clock; a scanning optical system scanning an image surface in a main scanning direction, by focusing a deflected light beam, derived from the light beam of the light source, onto the image surface as a beam spot, the scanning optical system providing an amount of linearity at an outer peripheral end of the image surface; an optical writing unit controlling ON/OFF state of the light source in accordance with an image signal; a frequency dividing unit, connected to the optical writing unit, generating a secondary frequency of the pixel clock at an output thereof, which is equal to an initial frequency of the pixel clock at an input thereof divided by a divisor integer; and an electrical correction unit configured to adjust the secondary frequency of the pixel clock at the output of the frequency dividing unit with respect to each of respective pixels included in the image signal while the amount of linearity remaining at the outer peripheral end of the image surface is provided by the scanning optical system, when the beam spot is located near the outer peripheral end of the image surface, so as to obtain uniform-velocity characteristics, wherein the scanning optical system is configured to satisfy the conditions 0.5% ≦|Lin|≦10% where Lin indicates the amount of the linearity, and the scanning optical system including a scanning lens device having lens surfaces that are concentric with respect to a reflection point of a rotary deflector, and the number of the concentric lens surfaces in the scanning lens device is either equal to or larger than the number of non-concentric lens surfaces in the scanning lens device.