HP 4550 Service Manual - Page 132

Side registration adjustment The printer adjusts side registration so that the center of the paper (in the horizontal direction), matches the center of the printable area on the ITB when printing on the second side. The side registration guides press against both sides of the paper in order to complete the adjustment. The duplex driver PCB then drives the side registration motor (M3103) clockwise and moves the home registration guide to the home position. Once the side registration home position sensor (PS3105) detects the home position of the side registration guide, the duplex driver PCB stops M3103 and holds the side registration guide at the home position. Figure 5-34 Side registration adjustment When the duplex paper pick-up sensor (PS3103) detects paper, the paper is fed along the feed rollers. Once the duplex paper pick-up sensor (PS3103) detects the paper, the paper is stopped and the paper is freed from the feed rollers. According to the paper-size data received from the DC controller, the duplex driver runs the side registration motor (M3103) the prescribed number of pulses, moving the side registration guide and aligning the paper position. This completes the side registration in the paper process. Figure 5-35 Duplex feed roller pressure 130 Theory of operation C7085-90921