PRINTHEAD HAVING NON-UNIFORMITY CORRECTION BASED ON SPATIAL ENERGY PROFILE DATA, A METHOD FOR NON-UNIFORMITY CORRECTION OF A PRINTHEAD, AND AN APPARATUS FOR MEASURING SPATIAL ENERGY PROFILE DATA IN A PRINTHEAD

摘要

A printhead having a plurality of exposure elements (18) with improved non-uniformity correction. Spatial variance of the energy emitted by the exposure elements (18) is measured and used to establish spot size characteristics for each exposure element. A sensor (26) scans multiple points along the pixel area written by each exposure element (18) and measures a corresponding output power value at each point. The output power values are evaluated to determine a maximum output power value for the exposure element (18) and to obtain a spot size for the exposure element (18) based on full-width at half-power values. Both spot size data, which can thus be obtained and stored only once, and output power values are then used to correct for non-uniformity's between the exposure elements (18).