Method and apparatus for enhancing laser printer resolution by using a

Abstract

A resolution enhancement apparatus and method of a laser printer using a modulated laser beam is adapted to an image forming apparatus of the laser printer, and includes a memory for storing sequentially input image data in a sequential scanning method, rearranging a scanning line order and generating an M.times.M sample window, M being an integer, a first processor for producing (M-2).sup.2 3.times.3 sample windows using the M.times.M sample window, determining which mask pattern among a plurality of mask patterns is coincident with each of the produced 3.times.3 sample windows, and outputting predetermined data with respect to direction and density of the image data according to the mask pattern, a second processor for determining to which group among a plurality of groups the image data belongs by using the predetermined data output from the first processor, and altering the image data into predetermined image data corresponding to the group to output the altered data, and a signal modulator for modulating the data output from said second processor into a predetermined pattern and outputting the modulated pattern, thereby minimizing the use of memory space by using four row line memories and enhancing resolution by expressing finite shapes according to nineteen modulation patterns while eliminating the more severe portions of pixel magnitude variation (step phenomenon).