When a laser beam is scanned on the surface of a photo receptor, the scanning time from Start of Scan (S.O.S.) to End of Scan (E.O.S.) varies. This variation is due to several factors, primarily the motor speed fluctuation. This variation in speed is defined as jitter.

The basic structure of our measurement method of jitter is shown in the figure below. In this figure, the polygon scanner is running at the rated speed. Scanning time, the reflected laser beam to travel between detector A and B, is measured by the high speed counter.

NOTE: There are several different components of jitter. One of the components that has a significant effect on the overall jitter is the spot size of the laser beam on the mirror facet. The smaller the spot size, in general, the higher the overall jitter. To keep the jitter value as low as possible, we advise our customers to use the largest spot size on the mirror facet that will work in their system. A beam spot size on the mirror facet of ø 3mm (0.12 inch) or larger is a good starting point.