HP 3500 Series

ENWW Pickup/feed system 177
Pickup/feed unit
The pickup/feed unit, being comprised of the pickup unit and feed unit, picks up paper from the
Tray 2 (cassette) or Tray 1 (multipurpose tray) pickup tray one-by-one and feeds it into the printer
until it reaches the fuser.
Figure 5-58 diagrams the pickup/feed unit.
The following is the pickup/feed sequence of operation.
1 The printer controls the fuser heater temperature and drives the scanner motor upon receipt of
a print command from the formatter.
2 When the fuser heater reaches a specified temperature, it drives the feed motor (M1).
3 The solenoid at each paper pickup source is turned on after a specified period from the
scanner motor drive start.
• Tray 1 (multipurpose tray): Tray 1 solenoid (SL1)
• Tray 2 (cassette): Tray 2 pickup solenoid (SL2)
As each pickup solenoid is turned on, each pick up roller rotates and picks up paper. The
separation pad prevents the double feeding of paper.
As the registration clutch (CL1) is turned on at the same time as solenoids, both the
registration roller and the feed roller rotate the paper is fed to the registration roller.
4 When the scanner is ready, the drum motor (M3) drives and rotates the ITB.
5 After a specified period since the drum motor (M3) drive start, the secondary transfer roller
engaging solenoid (SL4) is turned on and pushes the secondary transfer roller against the ITB
to rotate the roller. (See “Secondary transfer roller engaging/disengaging control” on page 5-
166 for details)
6 The registration shutter corrects the skew of the paper at the registration roller.
7 When the paper is detected by the registration paper sensor (PS4) after passing the
registration roller, the registration clutch (CL1) is turned off and stops the paper.
8 When the paper end reaches the edge of the image on the ITB, the registration clutch (CL1) is
turned on. This allows the paper to be fed.
The feeding speed changes based on the media specified by the formatter. (See Paper feeder
for details)
9 The toner is transferred onto the paper on the ITB and the paper is then fed to the
fuser/delivery unit.