HP Color 9850mfp Service Manual - Page 365

II UNIT EXPLANATION Q5686A/Q5687A 5.2 Operation FOLDING/THREE-FOLDING (Q5687A ONLY) 5.2.1 Folding knife control The folding knife driven by the folding knife motor (M719) is used in the folding, stitch-and-fold, and threefolding modes. In the three-folding mode, it is used at the first folding. A. Folding knife operation The folding knife motor (M719) rotates the crank shaft a half turn through gear to thrust the folding knife [1] to the nip section of the folding roller [2]. The folding roller pulls in the paper and presses it down for folding. The folding position is controlled according to the stop position of the booklet stopper. [3] PS722 [1] [2] B. Folding knife control A specified period of time after the folding passage sensor (PS726) detects paper and the booklet stopper stops at the folding position, the folding knife motor (M719) turns on to thrust the folding knife to the paper. The folding knife sticks out and draws back once, and stops when the folding knife HP sensor (PS722) detects the change from "H" to "L." 2-35