HP LaserJet 6p/mp Service Manual - Page 68

Basic sequence of operation The Formatter PCA and the DC Controller PCA share information during printer operation. The DC Controller-to-Formatter Connector (J201) forms a link that operates as a serial data bus. This allows printer status, command information, and dot-image data to be passed between the two PCAs. Figure 5-7 shows the general timing of the printer events. The following events take place during normal printer operation: Table 5-2 Printer timing Period Timing Purpose WAIT From when the paper is inserted to the end Clear the drum surface potential and clean of Main Motor initial rotation. the Transfer Roller. STBY (standby) From the end of the WAIT or the LSTR period until the input of the PRNT signal from the Formatter. Or from the end of the LSTR period until power OFF. Maintain the printer in ready state. INTR (initial rotation) From the input of the PRNT signal from the Stabilize the photosensitive drum Formatter until the laser diode intensity has sensitivity in preparation for printing. Also been stabilized. clean the Transfer Roller. PRNT From the end of initial rotation until the Scanner Motor stops. Form images on the photosensitive drum based on the /VDO signal from the Formatter and transfer the image to paper. LSTR (last rotation) From the primary voltage (DC) OFF until Deliver the last sheet of paper. Also clean the Main Motor stops. the Transfer Roller. If another PRNT signal is sent from the Formatter, the printer returns to the INTR period. If not, it returns to the STBY period. Refer to the Timing Diagrams on the following pages. 66 Functional overview EN