Diagnostic Aids
3-27
4520-xxx
Fuser Operation
Hot Roll Fuser
The hot roll fuser is made up of two primary assemblies. The first
assembly is the top fuser cover which contains the thermistor/cable,
thermal fuse, cable assembly, left and right lamp brackets and cover.
This is a complete assembly and the parts cannot be individually
replaced as in previous Lexmark laser printers.
The thermal fuse (two fuses in series) protects the fuser assembly
and surrounding parts from ignition in the event of a failure in the
fuser control circuitry by opening the AC circuit to the lamp. The
thermistor assembly is designed to keep the temperature of the
fuser hot roll within a predetermined temperature by being in contact
with the fuser hot roll and changes resistance as the temperature of
the hot roll increases. The thermistor resistance changes from
approximately 150K ohms to approximately 260K ohms as the
temperature of the fuser hot roll increases. The thermistor is
connected to the fuser control board connector J2-1 and J2-2 and
from J2 to J1-2 and J1-3 on the fuser control board to J16-2 and
J16-3 on the engine board. J16-2 (THERMGND) and J16-3
(THERM) are connected to module U10. U10 monitors the change
in thermistor resistance and sends a signal (HEATON) from J30-A25
through the interconnect board to CN3-9 on the LVPS to signal the
triac to turn the fuser lamp on or off to maintain the correct fuser
temperature.
The voltage drop across the thermistor is proportional to the fuser
temperature and varies from approximately 2.0 V dc (cold) to 2.3 V
dc (warm during idle) to approximately 2.7 V dc during continuous
printing. These voltages are assuming the fuser temperature is set
to normal. The HEATON signal from CN3-9 varies from 0 V dc (lamp
on) to +5 V dc (lamp off) and is connected to the cathode of an Opto
triac to control the fuser lamp. The second part of the assembly is
the fuser frame which contains the hot roll, backup roll, and
associated parts as well as the paper exit guide assembly, narrow
media sensor, fuser control board and the envelope conditioner
solenoid.
Summary of Contents for T52 Series
Page 8: ...viii Service Manual 4520 xxx ...
Page 10: ...x Service Manual 4520 xxx Class 1 Laser Statement Label ...
Page 17: ...Notices and Safety Information xvii 4520 xxx Japanese Laser Notice Chinese Laser Notice ...
Page 24: ...xxiv Service Manual 4520 xxx ...
Page 162: ...3 30 Service Manual 4520 xxx ...
Page 224: ...5 2 Service Manual 4520 xxx ...
Page 231: ...Connector Locations 5 9 4520 xxx Engine Board ...
Page 232: ...5 10 Service Manual 4520 xxx Controller Board Non Network ...
Page 233: ...Connector Locations 5 11 4520 xxx Controller Board Network ...
Page 235: ...Connector Locations 5 13 4520 xxx ...
Page 237: ...Connector Locations 5 15 4520 xxx 210 220 001 002 ...
Page 239: ...Connector Locations 5 17 4520 xxx ...
Page 242: ...5 20 Service Manual 4520 xxx ...
Page 246: ...7 2 Service Manual 4520 xxx Assembly 1 Covers ...
Page 248: ...7 4 Service Manual 4520 xxx Assembly 2 Frame ...
Page 250: ...7 6 Service Manual 4520 xxx Assembly 2 Frame continued ...
Page 252: ...7 8 Service Manual 4520 xxx Assembly 3 Printhead ...
Page 254: ...7 10 Service Manual 4520 xxx Assembly 4 Paper Feed Autocompensator ...
Page 256: ...7 12 Service Manual 4520 xxx Assembly 5 Paper Feed Multipurpose Unit ...
Page 258: ...7 14 Service Manual 4520 xxx Assembly 6 Paper Feed Alignment ...
Page 260: ...7 16 Service Manual 4520 xxx Assembly 7 Paper Feed Output ...
Page 262: ...7 18 Service Manual 4520 xxx Assembly 8 Integrated Paper Tray 500 Sheet ...
Page 264: ...7 20 Service Manual 4520 xxx Assembly 9 Main Drive ...
Page 266: ...7 22 Service Manual 4520 xxx Assembly 10 Developer Drive ...
Page 268: ...7 24 Service Manual 4520 xxx Assembly 11 Hot Roll Fuser ...
Page 270: ...7 26 Service Manual 4520 xxx Assembly 12 Transfer ...
Page 272: ...7 28 Service Manual 4520 xxx Assembly 13 Charging ...
Page 274: ...7 30 Service Manual 4520 xxx Assembly 14 Electronics 1 ...
Page 276: ...7 32 Service Manual 4520 xxx Assembly 14 Electronics I continued ...
Page 278: ...7 34 Service Manual 4520 xxx Assembly 15 Electronics II ...
Page 280: ...7 36 Service Manual 4520 xxx Assembly 16 Electronics III ...
Page 282: ...7 38 Service Manual 4520 xxx Assembly 17 Electronics IV ...
Page 284: ...7 40 Service Manual 4520 xxx Assembly 18 Electronics V ...
Page 286: ...7 42 Service Manual 4520 xxx Assembly 19 Electronics VI ...
Page 288: ...7 44 Service Manual 4520 xxx Assembly 20 250 Sheet Tray ...
Page 290: ...7 46 Service Manual 4520 xxx Assembly 20 250 Sheet Tray continued ...
Page 292: ...7 48 Service Manual 4520 xxx Assembly 21 Integrated Paper Tray 250 Sheet ...
Page 294: ...7 50 Service Manual 4520 xxx Assembly 22 500 Sheet Tray ...
Page 296: ...7 52 Service Manual 4520 xxx Assembly 22 500 Sheet Tray continued ...
Page 298: ...7 54 Service Manual 4520 xxx Assembly 23 Duplex Unit ...
Page 300: ...7 56 Service Manual 4520 xxx Assembly 23 Duplex Unit continued ...
Page 302: ...7 58 Service Manual 4520 xxx Assembly 23 Duplex Unit continued ...
Page 304: ...7 60 Service Manual 4520 xxx Assembly 24 Envelope Feeder ...
Page 306: ...7 62 Service Manual 4520 xxx Assembly 25 High Capacity Feeder ...
Page 308: ...7 64 Service Manual 4520 xxx Assembly 25 High Capacity Feeder continued ...
Page 310: ...7 66 Service Manual 4520 xxx Assembly 25 High Capacity Feeder continued ...
Page 312: ...7 68 Service Manual 4520 xxx Assembly 25 High Capacity Feeder continued ...
Page 314: ...7 70 Service Manual 4520 xxx Assembly 25 High Capacity Feeder continued ...
Page 316: ...7 72 Service Manual 4520 xxx Assembly 26 Kiosk Vertical Paper Adapter ...
Page 318: ...7 74 Service Manual 4520 xxx Assembly 27 Kiosk Horizontal Paper Adapter ...
Page 324: ...7 80 Service Manual 4520 xxx ...
Page 334: ...I 10 Service Manual 4520 xxx ...