HP 8000dn Service Manual - Page 162

Paper Jam Detection The PIU Sensor (PS2), the Registration Sensor (PS1), the Fuser Delivery Sensor (PS1403), and the Face-Down Delivery Sensor (PS1402) detect paper moving through the printer (see figure 5-15 on page 118 and table 5-1 on page 119 for a description of each sensor and illustration of its locations). If a paper jam is detected, the DC Controller immediately stops the printing process and causes a message to be displayed on the control panel. If a paper jam occurs in the Envelope Feeder, duplexer, 2000-sheet Input Tray, Multibin Mailbox/5-bin Mailbox with Stapler, 2 x 500-sheet Input Tray, or 7-bin Tabletop Mailbox, the message will indicate the approximate location. See Chapter 7 for more details. Printer Timing The Formatter PCA and the DC Controller PCA share information during printer operation. This information consists of printer status, command, and dot-image data. Figure 5-23 and figure 5-24 show the general timing of the printer events. Table 5-7 lists the events that take place during normal printer operation. Table 5-7. Printer Timing Period Timing Purpose WAIT From power on to the end of Main Motor initial rotation. Clear the drum surface potential and clean the Transfer Roller. STBY (standby) From the end of the WAIT or the LSTR period until Maintain the printer in the READY the input of the PRNT signal from the Formatter state. PCA. Or from the end of the LSTR period to power off. INTR (initial rotation) From the input of the PRNT signal from the Formatter PCA until the laser diode intensity has been stabilized. Stabilize the photosensitive drum sensitivity in preparation for printing. Clean the Transfer Roller. PRNT (print) From the end of the initial rotation until the Scanner Form images on the photosensitive Motor stops. drum based on the /VDO signal from the Formatter PCA. Transfer the image to the media. 138 Chapter 5 Functional Overview EN