HP CP6015dn Service Manual - Page 665

Alignment of paper The alignment motor (M5) drives the alignment plates each time paper is output, putting both left and right edges of the sheet in order. The alignment-plate motor is a four-phase stepping motor. The position of the alignment plate is identified by the number of motor pulses from the alignment-plate home-position sensor (PI5). The following briefly describes how the saddle-stitching mechanism operates on two sheets. 1. When the first sheet is output, the alignment plates touch the left and right edges of the stack (first alignment). The alignment plates leave the home position in advance and wait at points 10 mm from the edges of the stack. Figure 8-62 Paper alignment (1 of 8) Sheets Alignment plate Alignment plate Paper positioning plate Alignment plate home position sensor (PI5) 2. The alignment plates move away from the stack and then return (Second alignment). Figure 8-63 Paper alignment (2 of 8) 3. The alignment plates move 10 mm from the edge of the stack. Figure 8-64 Paper alignment (3 of 8) 4. When the stack arrives, steps 1 through 3 repeat. ENWW Theory of operation 623