Service manual

ENWW Chapter 5 Theory of operation 103
Sheet feeders
HP LaserJet 2300 series printers can use two optional sheet feeders: the 250-sheet feeder and
the 500-sheet feeder.
The sheet feeders are driven by the printer and controlled by the printer’s engine controller. The
engine controller drives the solenoid at a necessary timing through the sheet feeder PCA. The
paper sensor detects media.
The sheet feeder picks up media loaded in the cassettes and transports it to the printer.
The flow of media is illustrated in figure 33 (the 500-sheet paper feeder is shown).
Figure 33. Pickup-feed paper path
The main motor (M903) uses gears to drive the sheet feeder.
When a print command is received from the formatter, the main motor (M903), reverse motor
(M904), and scanner motor start rotating. The heating element temperature begins to rise.
The sheet feeder pickup solenoids (SL2001, SL2002) are turned on when the following three
requirements are met:
● the main motor has been driven for 0.35 seconds
● the scanner motor has reached the specified rotation number
● the heating element temperature has been brought to the specified temperature, or the
specified period of time has elapsed after start of the temperature control
SL2001 and SL2002 transmit the main motor’s rotation to the pickup roller. The pickup roller
makes a rotation to pick up media in the cassette.
The separation pad separates the media and transports it to the printer. The media goes through
the transfer, separation, and fuser/delivery blocks, and is delivered to the selected tray.