II. LENS DRIVE SYSTEMA. Movement of the Lens1. OutlineThe lens assembly is driven by the lens motor (M3).The machine uses center reference, in which copy paper is centered along thefeeding path for pick-up and feeding. Figure 3-201 shows the spatial relationshipbetween copy paper and original.When the power switch is turned on, the lens motor (M3) starts to rotate, moving thelens in the direction of the lens home position sensor (PS19). The lens motor starts torotate in reverse when the signal plate blocks the lens home position sensor, and stopswhen the lens is at Direct position.The microprocessor on the DC controller remembers the Direct position of the lens.When the ratio is changed, drive pulses corresponding in number to the selected ratiowill be applied to the lens motor to promptly change the position of the lens.When moving in Enlarge direction (as from Reduce to Direct), the lens is first movedpast the position for the selected ratio; it is then moved back to the appropriate positionby rotating the lens motor in reverse, thereby ensuring correct positioning of the lens.Figure 3-2013-2CHAPTER 3 EXPOSURE SYSTEMCOPYRIGHT © 1997 CANON INC. CANON NP6330 REV.0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)Copyboard glassOriginal CopierReferenceCopy paper
