User Guide

Paper-pickup-and-feed system
The pickup-and-feed system consists of various rollers that the printer motors drive. The printer uses
tray 1 (the manual feeding tray) and a cassette in tray 2 as media sources. The printed media is
delivered to either the rear output bin (straight-through printing) or the top output bin (the default
destination). One 500-sheet feeder and one 1,500-sheet feeder can be added to HP LaserJet
4200/4300 Series printers. Two additional 500-sheet feeders and one 1,500-sheet feeder can be
added to HP LaserJet 4250/4350 Series printers. These accessories are discussed later in this
chapter.
The tray 1 paper sensor (on the tray 1 pickup assembly; PS105) detects media in tray 1. The tray 2
paper sensor (PS101) detects media in tray 2. The paper-size sensor (PS106) and the paper-size
switch (SW102) detect the media that is loaded in the tray 2 cassette.
Two motors, a clutch, and a solenoid that are controlled by the dc controller PCA drive all of the
rollers in the HP LaserJet 4200 Series printers. The HP LaserJet 4250, 4300, and 4350 Series
printers use three motors, a clutch, and a solenoid. See
Motor and fan control.
The pre-feed, top-of-page, and fuser-assembly delivery sensors (PS102, PS103, PS108) detect
media arriving and passing along the paper path. If the media does not reach or pass these sensors
within a specific amount of time, the microprocessor on the dc controller PCA halts the printer
functions and a jam error message appears on the control-panel display. See
Alphabetical printer
messages and Numerical printer messages.
For information about the location of printer switches, sensors, and motors see
Printer switches and
sensors and Printer motors and fans.
114 5 Theory of operation