Chapter 3 Image Faults; Initial Checks - Canon NP6621 Service Handbook

CHAPTER 3 IMAGE FAULTS

A. Initial Checks
1. Site Environment
a. The site must provide the rated power supply
voltage ±10%.
b. The site must not be subject to high or low
temperature/humidity; avoid areas near water
faucets, water boilers, and humidifiers. Avoid
areas near sources of fire or areas subject to
dust.
c. The site must be free of ammonium gas.
d. The site must be free of direct rays of the sun;
otherwise, provide curtains.
e. The site must be well ventilated.
f. The site must keep the machine level.
Check the site against the above requirements.
2. Originals Used
Identify whether the problem is due to the origi-
nals used or to the machine.
a. Originals with a reddish background can gener-
ate copies with poor contrast; for example,
reddish sheets and slips.
b. Originals which are diazo copies or which have
high transparency can generate copies that can
be mistaken for "foggy" copies.
Originals prepared in light pencil can generate
copies that can be mistaken for "light" copies.
3. Copyboard Cover and Copyboard
Glass
Check the copyboard cover and the copyboard
glass for dirt and scratches. If dirt is found, clean the
part using a solution of mild detergent or alcohol. If
scratches are found, replace the part.
4. Paper
a. Is the paper of a type recommended by Canon?
b. Is the paper moist? Try paper fresh out of
package.
5. Others
In winter, bringing a machine subjected to the
cold of a warehouse into a warm room can cause
condensation inside the machine, leading to vari-
ous problems.
Ex:
a. condensation on the scanning system
(glass, mirror, lens) can generate light im-
ages.
b. condensation on the charging system can
cause electrical leakage.
c. condensation on the pick-up/feeding guides
can cause feeding problems.
If condensation is noted, dry wipe the part or
leave the machine alone powered for 60 min.
IMAGE FAULTS
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