Canon GP215 Service Handbook page 169

q q L-TEST1:
solid black test print
• Use it to check white spots or white lines.
• If white spots are noted, suspect dirt on the
transfer charging roller or the separation
static eliminator.
• If white lines are noted, suspect shading
faults because of dirt on the standard white
plate.
w w L-TEST2:
halftone test print
• Use it to check for transfer faults, black
lines, white lines, or uneven intervals.
• If transfer faults are noted (vertical white
spots), suspect dirt on the transfer charging
roller or the separation static eliminator.
• If black lines are noted, suspect scratches
on the drum or dirt on the primary charging
roller.
e e L-TEST3:
blank test print
• Use it to check for fogging.
• If fogging is noted, suspect a fault in the
photosensitive drum, developing system, or
laser system.
r r 17-gradation test print
• Use it to check gradation and check for fog-
ging, white lines, and uneven (left/right)
density.
• If gradation is not good, suspect a fault in
the laser system.
• If fogging is noted, suspect a fault in the
photosensitive drum, developing assembly,
or laser system.
• If white bands are noted, suspect a fault in
the developing system or dirt on the trans-
fer charging roller.
If white lines are noted, suspect a shading
fault because of dirt on the standard white
plate.
• If uneven density (left/right) is noted, sus-
pect dirt on the primary charging roller or a
fault in the developing system.
SERVICE MODE
7–61