11: Head-To-Drum Gap; Manuf X-Axis (Scanner) - Xerox Phaser 840 Service Manual

11: Head-to-Drum Gap

This print indicates if the gap between the
printhead and the drum is correct.
Lines.
The horizontal lines of the print are
made up of long and short dashes. Inspect the
first and last 1/2 in. (12 mm) of the black lines
for the vertical distance between the short
dashes and long dashes:
If the short dashes are any distance
I
below, inline, or slightly above (with no
separation) with the long dashes, then the
drum gap is correct.
If the short dashes are above the long
I
dashes with significant line separation,
then the drum gap is too wide and must be
readjusted.
If the short dashes on one side of the print
I
extend farther below the long dashes than
on the other side of the print with a
noticeable difference (1/64 in., 0.4 mm or
more), or if the short dashes extend below
the long dashes on one side of the print
and the short dashes extend above the
long dashes on the other side of the print
(with line separation), then the printhead is
skewed and must be readjusted.
Text. Examine each end of the band of text.
Look for fuzziness or differences between the
quality of the characters on the left and right
ends of the print. A difference indicates the
printhead gaps at each end of the printhead are
not equal.
Perform the procedure "Printhead-to-drum
spacing adjustment (Phaser 840 Printer Only)",
on page 4-146. The Phaser 850/860 printer.
should never require this adjustment
12.: Manuf x-axis
(scanner)
This print is used for manufacturing and
engineering evaluation of printhead
performance.
5 - 166 Phaser 840/850/860/8200 Color Printer - Service Manual
EFGHIJKLMNOPQ
EFGHIJKLMNOP
FGHIJKLMNOPQ
EFGHIJKLMNOPQ
EFGHIJKLMNOP
EFGHIJKLMNOP
Time_to_Drum/Head_to_Drum test print:
Short dashes above the line indicate large time_to_drum and/or large head_to_drum gap.
Short dashes below the line indicate small time_to_drum and/or small head_to_drum gap.
Indicates
optimum head-to-drum
gap setting
0388-39