HP Color 9850mfp Service Manual - Page 146

II UNIT EXPLANATION IMAGE STABILIZATION CONTROL 14.4 Dot diameter adjustment control hp Color 9850mfp The dot diameter adjustment control is a method by which intermediate exposure potential is output stably, regardless of the changes in the sensitivity of photosensitive materials or the stain of the writing system. The laser output is controlled by the printer control board (PRCB) so that the intermediate exposure potential that is determined by the PWM128 value for each color is between a developing bias value determined by the Dmax control and a maximum exposure potential. A. Explanation of the operation The drum potential exposed with a PWM128 value is read by the drum potential sensor and the MPC value for the laser is corrected to be within the standard value. B. Timing of the operation • When the main switch (SW2) is turned on for the first time in 6 hours or more after it was turned off. • When the job starts 6 hours or more after the SW2 has been turned on. • Every 1,000 pages of output. However at the time of completion of the job, when the 1,000th page is contained in the job. • When the humidity has changed more than 30% RH from the value measured at the last operation. • When the job starts where the process speed gets slowed down to 1/2 or 1/3 speed. However, once operated under this condition after the SW2 turns on, the operation is not carried out under this condition until the SW2 turns off. 2-72