HP LaserJet II Serie Manual De Instrucciones página 241

HP 33440/HP 33449 COMBINED SERVICE MANUAL
Transfer Corona
The Transfer Corona applies a positive charge to the back of the paper during the transfer
process to attract the toner image from the surface of the photoconductive drum to the paper.
The High-Voltage Power Supply Assembly provides the voltage applied to the Transfer Corona
Assembly. The main microprocessor on the DC Controller PCA enables the Transfer Corona via
the HIGH-VOLTAGE TRANSFER ON (HVTON) signal, which occurs approximately two seconds
atier the PRNT command is issued by the Interface/Formatter PCA. The Transfer Corona remains
on until dl printing is complete,
Table 7-46. Transfer Corona Checks
1. Is the High-Voltage Power Supply Assembly
correctiy seated into iti connectors to the DC
Controller PCA?
2. Is the Transfer Corona wire broken?
3. Is the drum ground connector (see Figure
7-28) damaged?
4.
Are the Transfer Corona Assembly spring
connectors (located on the bottom of the
High-Voltage Power Supply Assembly
connector arm) dirty or bent?
5. Is the DC Controller PCA defective?
Vlsudly inspect. If necessary, remove the
assembly to vetify that dl pins are in their
respective connectors.
Inspect. If the wire is broken, replace the
assembly.
Inspect. Replace the High-Voltage Power
Supply Assembly if necessary.
Remove the High-Voltige Power Supply
Assembly. Inspect the Transfer Corona spring
connections (see Figure 7-28). Straighten or
clean the connectors if necessary.
See the "Transfer Corona Functional Check"
which follows.
Transfer Corona Functional Check
Veri& that the Transfer Corona enable signal (HVTON) on the High-Voltige Power Supply
Assembly is functioning as follows
1. Using a voltmeter and frame ground as a reference, measure the voltage level at J21O-10 (Test
Connector, see Figure 7-30) on the DC Controller PCA while initiating the printer Self Test,
The voltage level should toggle between +18.0 Vdc (disabled state) to 0.0 Vdc (enabled state)
No seconds tier the print cycle begins. If the voltage at J21O-10 does not toggle, replace the
DC Controller PCA. If the signal line is being switched but the Transfer Corona does not
appear to be functioning (i.e., producing a clear image on the drum but faint or white pages),
replace the High-Voltage Power Supply Assembly followed, if necessary, by the Transfer Corona
Assembly.
7-77