9-18
Phaser 440 Color Printer
9
Checks and Adjustments
Thermal head skew (to correct speckle and wrinkle)
This adjustment corrects for speckles in the prints. This adjustment allows you
to set the skew of the thermal head's elements in relation to the drum surface as
illustrated in Figure 9-3. Properly setting the skew of the thermal head places
the printing elements in parallel, optimum contact with the length of the drum,
eliminating speckles and wrinkling.
1.
Turn off the printer. Load the paper tray with transparency film. Be
sure to set the media select switches on the side of the tray.
2.
Remove the top rear cabinet panel to access the engine control board.
Refer to the Chapter 8 topic “Printer cabinet panels” on page 8-4.
3.
Set all the DIP 1 Switches off.
4.
Press and hold the
TEST
button and turn on the printer. Release the
TEST
button. The printer is now in service mode.
5.
Select test pattern 0, check/inspection pattern, by ensuring that all
DIP 1 switches are off.
6.
Toggle DIP Switch 1-8 on then off to start the print on transparency
film.
7.
Examine the print for speckle. Speckles appear as pale blue dropouts
in the blue field of the print on the left or right (or perhaps both) edges
of the print. If speckle appears, go to Step 10. Otherwise, go to Step 8.
8.
With a screwdriver, turn the pitch adjustment screw on the affected
side one turn counterclockwise. (Counterclockwise turns pull the
affected end of the printhead forward relative to the axis of the drum.)
9.
Print out another test print and examine it for speckles. Repeat Step 8
and 9 until speckles first appear.
10.
Now that speckles are apparent in the test prints, rotate the skew
adjustment screw on the affected side(s) of the thermal head one turn
clockwise. Print out a speckle test pattern. Continue this adjustment
until you reach the point in which speckles disappear from the test
prints. (Clockwise turns push the affected end of the printhead
rearward relative to the axis of the drum.)
11.
Rotate the pitch adjustment screw an additional one turn clockwise to
finish the adjustment.
12.
Apply cement compound to the screws to lock it in its current
position.
Tools required
■
#1 POSIDRIV
®
■
cement compound
■
Phillips screwdriver
■
transparency film