| 摘要 |
PROBLEM TO BE SOLVED: To determine a 'scanner ready' state quickly by detecting the time variation of rotational speed when the rotational speed of scanner motor in a laser beam printer falls within a specified rotational speed range and comparing the detected variation with a predetermined variation rate. SOLUTION: After starting rotation of a scanner motor 603, a decision is made whether a count flag is O or 1. When the count flag is 0, rotational speed of the scanner motor 603 is waited for dropping below a lower limit and the r.p.m. dropping below the lower limit is stored in register A. A timer value for calculating the time variation of r.p.m. is then set such that at least the variation of r.p.m. can be calculated. Upon expiration of a time, the r.p.m. is stored in register B and if the absolute value of the time variation of r.p.m. is lower than a predetermined variation rate, a 'scanner ready' is transmitted to the image forming section of an engine and the operation is ended. |
