High-Voltage System Checks; Transfer Corona Checks - HP LaserJet II Serie Manual De Instrucciones

HP 33440/HP 33449 COMBINED SERVICE MANUAL
2.
Sealing tape not
removed.
3.
Broken Transfer
Corona wire or no
Transfer Corona
voltage.
4. No Developing
Bias.
5. No
drum
ground path.
6. Drum is not
rotating.
7. High-Voltage
3ystem
shorted-to-ground.
3. Bad
Laser/Scanning
3able Assembly.
1. Bent Top Cover
issembly Hinge
3rackets.
10. Blocked Laser
3eam.
Table 7-43. Wtite or Blank Pages
No toner is available for print.
No toner is available for print.
Without Transfer Corona voltage, toner
cannot be attracted from the surface of the
drum to the paper.
The Developing Bias applies a charge to the
developing cylinder which, in turn, passes
a charge to the toner. The charged toner
pafides are attracted to the neutralized
surface areas of the drum previously
discharged by the laser. If the charge on the
toner is missing, toner will not be attracted
to the drum and the page will be totily
whik.
If the drum ground discharge path is
interrupted, the laser light's discharging
effect mnnot occur and the highly negative
charge placed on the drum by the Primary
Corona will repel toner, leaving a white
page.
If the drum does not rotite, the page will be
white because the EP process functions will
not have occurred.
When the Transfer Corona is
shorted-to-ground, the current-limiting
circuitry within the High-Voltage Power
Supply Assembly disables ~ EP process
functional voltages. Without these voltages,
none of the EP process functions will occur.
Low-level signrds exchanged between the
Laser/Scanning Assembly and the DC
Controller may be affecting laser output.
With bent Hinge Brackets, the
Beam-to-Drum Mirror may improperly
reflect the laser beam or the drum drive
gear may not engage.
[f the Beam-to-Drum Mirror or EP-S
Cartridge shutiers do not open when the
EP-S Cartridge is instiled, the beam will
not reach the drum, resulting in an all-white
page.
..
.',.
AHON
Replace the EP-S Cartridge.
Remove tipe.
Perform the "Image
Development (Hrdf Self Test)
Functional Check" which
Followsto check dl other EP
processes.
Refer to Table 7-45,
"High-Voltage System
Ohecks."
Refer to Table 7-45,
"High-Voltage System
Checks."
Perform the "Drum Rotation
Functional ChecV' which
follows.
thoroughly clean or replace
the Transfer Corona
Assembly.
Replace the Laser/Scanning
UableAssembly.
?eplace the Top Cover
4ssembly Hinge Brackets..
Jerify the laser beam is not
]locked from striking the
1P drum (see the following
'Beam-to-Drum Mirror
Assembly Functional Check').
7-69