HP 3390 Service Manual - Page 106

Basic operation This chapter presents an overview of the relationships between major components in the all-in-one, and includes a detailed discussion of the image-formation system. The following systems are discussed: ● Engine control system ● Laser/scanner system ● Pickup/feed/delivery system ● Image-formation system Figure 4-1 HP LaserJet 3390/3392 all-in-one system block diagram Sequence of operation for the base unit Operational sequences are controlled by the microprocessor and the DC controller. Table 4-1 Sequence of operation Name Timing Purpose WAIT From power-on until the end of the main-motor initial Detects the presence of a print cartridge; clears drive potential from the drum surface and cleans the transfer roller See Table 4-2 Power-on sequence on page 85 for a complete description of the WAIT (power-on) period. STBY (standby) From the end of the WAIT or LSTR period until either Prepares the all-in-one to receive print commands a print command is sent from the formatter or the power is turned off INTR (initial rotation) From the time of the print command until the pickup Prepares the photosensitive drum for printing solenoid is turned on 84 Chapter 4 Theory of operation ENWW