Epson TM-U375 Technical Manual page 82

CONFIDENTIAL
Problem
Paper roll is not fed or
paper roll feed pitch is
irregular.
Paper roll is not take up
or is taken up loosely.
Cut sheet is positioned
correctly, but printer
does not detect it. Or
cut sheet eject waiting
status is not released
when cut sheet is re-
moved.
Cut sheet is not fed.
Table 4-3. Printer Mechanism Problems (continued)
Level
Probable Cause
Paper roll supply problem
J paper feed roller wear
Worn gears around paper
roll feed driving area
Spring-J holding roller
is unhooked or damaged.
Main circuit board unit
failure (Paper feed motor
drive signal failure)
J paper guide roller is
dislocated.
Paper take-up shaft as-
sembly wear or damage
Wear or damage on Pa-
per take-up gear, Paper
take-up torque spring,
or Paper take-up drive
pulley
Paper take-up belt is dis-
lodged or damaged.
V sensor sub-assembly
failure
Main circuit board unit
(detection circuit) failure
Cut sheet problem
Cut sheet is not inserted
properly.
Obstacle in paper path
inside printer
Cut sheet feed driving
rollers wear
Solenoid-Paper hold-
i n g s w i t c h i n g w i r e
break
Checkpoint
A
Check whether paper roll cor-
responds to specifications.
A Check paper roll path for ob-
stacles.
B
Check surface of J paper feed
roller for wear and damage.
B Check gears for wear and dam-
age.
B Check to see if the spring is
unhooked or damaged.
B
Check input signal to paper
feed motor drive terminals of
CN12 with an oscilloscope.
A Check to see if J paper guide
roller is dislocated.
B Check Paper take up shaft
ass'y for wear and damage.
B
Check the parts for wear and
damage.
B
Check for seating of and dam-
age to the belt.
B
Insert paper and check sensor
output signal with an oscillo-
scope.
B
Check input of pin 8 of CPU,
U12. (Paper existence: LOW.)
A Check whether cut sheet cor-
responds to specifications.
A
Check if cut sheet is inserted
along the guide of Case-Main.
A Check paper path in printer for
obstacles.
B
Check Intermediate drive
roller, Intermediate holding
roller, and V paper feed roller
assemblies for wear.
Check resistance of the sole-
B
noid. (Nominal value: approx.
10 Ω ± 10%)
Action
Use paper roll that corre-
sponds to specifications.
Remove any obstacles
from paper path.
Replace J paper feed
roller shaft assembly.
Replace any damaged
gears.
Hook Spring-J holding
roller or replace it.
Replace Main circuit
board unit.
Attach J paper guide
roller.
Replace Paper take-up
shaft assembly.
Replace any damaged
parts.
Position the belt properly
or replace it.
Replace V sensor sub-
assembly.
Repair TOF/BOF sensor
circuit.
Use cut sheet that corre-
sponds to specifications.
(See Section 1.2.3, Paper
specifications .)
Insert cut sheet along the
guide.
Remove any obstacles.
Replace any worn parts.
Replace Solenoid-Paper
holding switching.
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