HP LaserJet II Serie Manual De Instrucciones página 224

HP 33440/HP 33449 COMBINED SERVICE MANUAL
Table 7-23. Black Pages
1. No Primary
Corona. (Blotchy
with undefined
border.)
2.
Laser/Scanning
Cable Assembly.
(Defined border)
3. Laser/Smnning
Assembly.
(Defined border)
4. DC Controller
PCA.
(Defined border)
The Primary Corona applies a negative
charge to the drum's surface which repels
the less-negatively-charged toner, except
in those areas exposed to the laser light.
Without the Primary Corona's charge,
bemuse of the erase lamps the drum's
surface would be neutral, attracting the
less-negatively-charged toner and, therefore,
creating a totally black image.
Low-level signals exchanged between the
Laser/Scanning Assembly and the DC
Controller may be affecting laser output.
Circuitry in the assembly is musing the
laser to run out of control.
If the laser drive circuitry is damaged so
that the laser is always on, the surface of
the drum would be constantly discharged
by the laser.
Table 7-24. Very Faint Print
F
1. Empty EP-S
Cartridge.
2. Weak or no
Transfer Corona
current.
No toner is available for print.
The Transfer Corona's purpose is to apply a
positive charge to the back of the paper to
attract the negatively charged toner image
from the drum to the paper.
3. Weak or no If no developer bias is available, toner is not
developer bias.
attracted to the drum's discharged areas.
4. Paper. The paper moisture content, conductiviv,
finish, etc., may not be acceptable for use in
the electrophotographic process.
5.
Drum ground A dirty' or damaged drum ground contact
path interrupted.
will not allow electrical discharge or
laser-exposed areas.
Replace the EP-S Cartridge.
If the problem persists, refer
to Table 7-45, "High-Voltage
Systems Checks."
Replace the Laser/Scanning
Cable Assembly.
Replace the Laser/Smnning
Assembly.
Replace the DC Controller
PCA followed by the I/F
PCA as required. Hinti
Disconnect the I/F PCA
from the DC Controller and
perform a Test Print to
determine the source.
Perform the "Image
Development (Half Self Test)
Functional Check" following
these tables and proceed as
directed.
Refer to Table 7-45, "High-
Voltage System Checks."
Try a known type and source
of paper. Refer to the Paper
Specifications Guide or
Chapter 2, Section 2-4.
Clean or repair the drum
ground conticts.
7-60