Xerox Phaser 8860 Service Manual page 246

If the Printhead does not reach the standby position, the Wiper Blade can contact or interfere
with the Printhead. Problems with the Wiper or Media Drive assemblies (including the clutch)
can cause excessive ripple and or drive power levels. Review the results of the Paper Path
Drive and the Wiper Shaft tests to verify the wiper mechanism drive is operating properly
before investigating problems indicated by this test. Variation in the Up and Down Drive charac-
teristics are often caused by CW/CCW drive differences in the Media Drive Assembly. A slip-
ping Head Maintenance Clutch could produce several out of bounds results. Check the clutch
using with the Wiper Shaft test. Incorrect Wiper Belt tension can introduce variation in several
ripple or position values, especially the turnaround recovery time.
Table 30 Wiper Drive Nominal Values
R# Characteristic Typical Value
0 Up Motion Drive Error (min) N/A
1 Up Motion Drive Error Ripple N/A
(min)
2 Up Distance (min) N/A
3 Lock Encounter Distance N/A
(min)
4 Lock Engage Distance (min) N/A
5 Lock Engage Peak (min) N/A
6 Down Motion Drive Error N/A
(min)
7 Down Motion Drive Error Rip- N/A
ple (min)
8 Down Distance (min) N/A
9 Lock Disengage Distance N/A
(min)
10 Lock Disengage Peak (min) N/A
11 Bottom Encounter Distance N/A
(min)
12 Turnaround Recovery time N/A
(sec)
Diagnostics
Print Engine Check Menu Tests
Result
Reports the average following error while
move the wiper up from the low limit to
the lock encounter point.
Reports the difference between the max
and min following error over the same
interval.
Reports the difference between the max
and min limits of travel when moving up.
Reports the distance up from the lower
limit of travel at which the head lock latch
is encountered.
Reports the distance up from the lower
limit of travel at which the head lock latch
engages.
Reports the peak following error at the
point the latch engages.
Reports the average following error while
move the wiper up from the low limit to
the lock encounter point.
Reports the difference between the max
and min following error over the same
interval.
Reports the difference between the max
and min limits of travel when moving up.
Reports the distance up from the upper
stall point at which the head lock latch
releases.
Reports the peak following error at the
point the latch releases.
Reports the distance up from the upper
limit of travel at which the wiper first
encounters the lower travel limit.
Reports the time following the start of the
turnaround motion that the motion drive
error return to normal in the opposite
direction.
Paper Path Drive Test
This test exercises the Media Drive gear train and shafts. This test runs the Media Drive gear
train for a short time to loosen up the gears and bearings. Next, the gear train is abruptly
reversed to capture the reversal transient (which includes the swing gear motion), and opera-
tion in the other direction. No media is needed for this test to run. However, check that the Tray
1 pick gear, Tray 2 Pick Clutch, and Head Maintenance Clutch are disengaged before running
this test. Verify proper Media Drive motor operation with the Media Path Motor test.
Excessive following error (fe) during the drive intervals might indicate:
• Weak Media Drive motor
• Shafts with high drive requirements due to dry or misaligned bushings, bent shafts, roller
tension springs too strong, shaft gear diameter too large, rollers that are hard or dirty.
• Media Drive Assembly with high drive requirements due to warpage, no lubrication, gear
diameter too large, or out of spec face gear
Excessive ripple may indicate heavy load, malformed gear teeth, eccentric gears, bent shafts,
dirt on rollers, or warped face gear. An out of spec transition time might indicate and issue with
the meshing gears or a bound up Media Drive Assembly swing gear. The power peaks indicate
when swing gears loose contact on one side (reducing the required power), and make contact
on the other side, accelerating the upper shafts in the opposite direction.
Table 31 Paper Path Drive Nominal Values
R# Characteristic
0 CW MP fe Av (counts)
1 CW MP fe Ripple (counts)
2 CCW MP fe Av (counts)
3 CCW MP fe Ripple (counts)
4 Swing Arm Transition Time
(sec)
Tray 2, 3, and 4 Lift Plate Drive Test
This test exercises the selected Lift Motor and Lift Plate mechanism. This test. raises the Lift
Plate until it stalls against the upper stop. If the tray is empty (the normal situation), the No
Paper Sensor is not activated, but the Paper Height Sensor is. If the tray contains 1 sheet of
media (additional media would distort the power and lift distance readings), both sensors
would are activated.
09/2007
6-26
Typical Value Result
N/A Reports the average drive following error
level in the foreword direction.
N/A Reports the average drive following error
ripple in the foreword direction.
N/A Reports the average drive following error
level in the backward direction.
N/A Reports the average following error rip-
ple in the backward direction.
N/A Reports the time that the lower portion of
the paper path drive is disconnected
while the swing arm transitions to the
other rotation direction drive position.
Phaser 8860/8860MFP Service Manual
Initial Issue