Beam scan type recording apparatus with electrically F theta correcting function

Claim 1

A beam scan type recording apparatus for deflecting and scanning using a deflecting means a laser beam emitted from a laser source periodically at each occurrence of a timing pulse signal so as to form an image on a photosensitive medium for recording a visible image comprised of dot images, comprising: a clock generator for generating a reference clock signal having a predetermined frequency; an address counter for altering the counting value by one in accordance with a dot clock signal outputted at a timing for recording one dot image so as to output the counting value as address data; a memory means for changing a time interval between adjacent occurrences of said timing pulse signal by storing numerical data representing time interval between emission timings of the laser beam corresponding to respective dot images at each address corresponding thereto so as to output the numerical data stored at the address corresponding to the address data input from said address counter, said numerical data corresponding to at least a center portion of said photoconductive medium in a direction of scan of the laser beam being different from said numerical data corresponding to end portions of said photoconductive medium in the direction of the scan of the laser beam; a dot clock counter being set the numerical data outputted from said memory means as a preset value in response to a load signal, counting the value by one in accordance with the reference clock signal outputted from said clock generator, and outputting said timing pulse signal when the counting value agrees with the present value, said timing pulse signal being returned to said dot clock counter as the load signal and being supplied to said address counter to rest it; and a driving means for driving said laser means according to image data in synchronous with said timing pulse signal outputted from said dot clock counter; whereby the scan of the laser beam is ensured at a predetermined speed without an optical correction means.