HP LaserJet II Serie Manual De Instrucciones página 234

HP 33440/HP 33449 COMBINED SERVICE MANUAL
Image Development (Half Self Test) Functional Check
The EP process can be subdivided into the following stages (see Chapter 5, Section 5-2):
Cleaning (Physid and Electrostatic).
Conditioning (Primary Corona and grid).
Writing (Laser Modulation).
Development (Formation of the Toner Image).
Transfer (Transfer Corona charge to transfer the image to paper),
The purpose of the Hdf SeMTest Check is to determine which of the EP processes are functioning.
Perform the test as follows:
1. Press the TESTPRINTbution.
2. After the paper has advanced halfway through the printer (the leading edge of the paper should
have advanced at least past the Transfer Corona), open the Top Cover Assembly.
3. Open the EP-S Cartridge's drum shield (see Figure 7-27) to view the drum's surface.
If a dark and distinct toner image is present on the drum's surface, assume that the first four
functions of the EP process are functioning, concentrate troubleshooting efforts to a transfer
problem, and proceed to Table 7-46. If the drum image is faint, veri$ proper laser power per
the "Laser Power Verifimtion" in Section 7-4, followed by the "High-Voltage System Checks,"
(Table 7-45) in this section. If NO image is present on the photoconductive drum, concentrate
troubleshooting efforts on the earlier stages of the EP process as follows
Drum Rotation Functional Check
The photoconductive drum, located in the EP-S Cartridge, must rotate for the EP process to
function. The photoconductive drum receives its drive from the Main Motor gear train. To verify
whether the drum is rotating, proceed as follows:
1.
2.
3.
Open the printer's Top Cover Assembly. Open the EP-S Cartridge's drum shield (cover) to view
the photoconductive drum.
With a felt-tipped marker, draw a tine on the edge of the drum (away from the print image
area). Note the position of the line.
CIose the printer and power it on. The one-second start-up sequence should rotate the drum
enough to move the mark. Open the printer and inspect the drum. Veri& that the mark drawn
in Step 2 of this procedure has moved.
If the mark has not moved, inspect the gear train to ensure that it is meshing with the EP-S
Cartridge gears. If the Main Motor and drive gears appear to be functional and yet the EP
drum does not move, the Top Cover Assembly Hinge Brackets may have been bent and require
replacement.
7-70