Laser scanner with diode and pixel-level beam intensity modulator

摘要

The scanner employs a polygonal mirror (12) with a control circuit (11) linked to a CPU (33). The CPU memory (31) contains the bit pattern of the image to be reproduced. The beam from the laser diode (16) is collimated (17) and split (18) into a scanning beam (L1) and a power measurement beam (L2). The beam intensity for each pixel is regulated to conform to its grey scale level. Each pixel is represented by a 10-bit data word giving 1024 levels of grey-scale information. A two-dimensional image is produced on a photoconductive drum (PD) and developed with toner. A mirror (21) outside the region covered by the scan reflects light on to a beam position detector (22) which clocks each movement.