HP 8550 Service Manual - Page 193

Scanner motor Figure 87 shows the circuit used to control the scanner motor. The circuit has the following functions: l Controls the direction of rotation of the scanner motor l Controls the speed of rotation of the scanner motor The scanner motor changes its direction of rotation to move the scanner forward and in reverse. The speed of its rotation during scanning varies according to the selected reproduction ratio. The scanner moves at four different speeds when moving in reverse. The greater the distance, the greater the speed. The four speeds are described below, compared to the forward speed with a 1:1 enlargement ratio. l One-page mode (7.7 times as fast) l Reverse distance of the mirror 1 mount is 105.1 mm or more (16.4 times as fast) l Reverse distance of the mirror 1 mount is 70.1 mm or more and less than 105.1 mm (9.3 times as fast) l Reverse distance of the mirror 1 mount is less than 70.1 mm (5.7 times as fast) Figure 87. Scanner motor circuit EN Copy module 191