近年來資訊業蓬勃發展，許多資料都需要藉由印表機的 工作，來得到完整的文件。印表機的列印工作由早期的點陣 式印表機到噴墨式印表機，一直發展至現今的雷射印表機。 其中雷射印表機穩定，高解析度的輸出品質，是其漸漸普遍 的原因。本文主要是在研究藉由旋轉多面鏡掃描在感光鼓上 的雷射光點之大小均勻性。因為光點大小的均勻性直接影響 了影像輸出的品質，可說是整個掃描系統之心臟部位。Recently, the information science is growing fast. There are many information which must be made by the printers . The developing processes of the printers are from the dots form to the jet form , then to the form of the laser printer. The stability of the laser printer, and the highly resolved output quality are the reasons of its r and popularity. The focus of this thesis is the study of the consistence of the spots of light on the light-sensing drum. Because the spot size and its uniformity and the consistence of the spots of light affect the output quality of the image directly, it is the heart of the whole scanning system.