|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ozone (O3) is a gas composed of three oxygen atoms combined in a
ring; ozone itself is a toxic, blue colored gas which has a
distinct odor. It is about one and a half times heavier than air
and decomposes readily into molecular oxygen. Ozone gas in large
quantities is poisonous to humans, animals and most plants.
Stratospheric Ozone is produced by nature with solar UV radiation.
The gas is also produced by electrical devices when these devices
are operational and under a load. Corona discharge is a natural
and common phenomenon that takes place while the copier is in
production. It is interesting to note here that most electrical
devices emit a low output of ozone gas and are not required to
have any filtering devices. In the Xerox Docutech family of
printers and copiers, the Ozone filter assembly (53K861) is
employed to filter the ozone gas before being discharged to the
atmosphere.
Almost every technician working on the Xerox Docutech family knows
that the electrically charged dicorotrons emit ozone when they are
under a load. Field engineering saw a need to filter the ozone gas
before it was discharged into the office environment and developed
the Ozone filter (53K72). As the fleet of copiers and printers
age, the filtering system starts to loosen up a wee bit and
becomes less effective. One of the first symptoms of the Ozone
system showing signs that things are not kosher in Denmark is a
deletion on your copies. Keep in mind that there are many
components in the Ozone filtering system and each component needs
to be fully inspected, cleaned and replaced as needed.
Ozone Filter Assembly - 53K861
The first place to start, in my opinion, is the filtration system.
Remove both rear panels and remove the toner filter housing
assembly (53K1190) to allow you better access to the Ozone
filtration system. While you are in back of the machine, program
the printer for one copy and observe the Ozone blower motor
(127E2801). Does the motor come up to full speed and can you feel
the discharge from the filter assembly? When the blower is
energized, it should have the same amount of force that a restroom
hand dryer has. This blower motor is extremely reliable and has a
very long service life. However they have been known to fail in
the field. It is recommended that the Ozone filter should be
replaced every 100 million copies. When you order the Ozone
filter, ask if they would ship you a refurbished filter. Or if you
are into some high level dirt you can purchase activated charcoal
(at the local garden supply house) and open the plastic housing
and change the charcoal yourself. When closing the unit, make sure
it is sealed with good epoxy cement. I have found K-B Weld to be
an excellent two part epoxy. If the Ozone filter and blower
assembly are operating properly, then the next component to check
is the Ozac Duct assembly.
Ozac Duct Assembly
Examine the two hoses that are connected to the Ozone filter
assembly— are they secure and in place? Are the hose clamps in
place (419W3250)? Check the condition of the plastic hose. Ozone
gas has been a known source of rapid decay of most manmade
materials. Some clever technicians have used duct tape to repair
the cracks in the hose but that fix is extremely temporary and
should be fixed by using a new Ozac Duct Assembly (5090=119K86,
DT135=600K24340). For proper examination, it is recommended that
the entire Duct assembly be removed for close inspection. On a
work bench or some other suitable work space, check for ozone
damage (cracks) to the hose.
NOTE: once the assembly is on the bench you may notice new cracks
on the hose assembly. This is an indication that the hose was
damaged by the ozone gas (over time) and would have failed if you
had not touched the assembly in the first place. If you notice
that any plastic hose clamps have broken, do not use any metal
hose clamps to replace them. The plastic hose clamps are not
spared in the Xerox parts manual but you can use plastic ty-wraps
instead. Use a vacuum cleaner to remove any internal debris in the
tube assembly and inspect the duct assembly to make sure there are
no obstructions. What we want to do is ensure maximum airflow
through the assembly. Check the ends of the Ozac tube assembly
that connect to the Dicorotron connectors for any debris or
blockage and make sure they are clean.
Dicorotron Connectors
Next on the hit list is the Dicorotron Connectors. In the Docutech
family of printers there are 6 connectors that are used.
Charge 00 Connector 114K281
Charge 1 Connector 114K281
Charge 2 Connector 114K281
Preclean Connector 114K261
Detack Connector 114K271
Transfer Connector 114K271
Remove all six connectors and inspect them for debris. In the past
I have soaked the connectors in film remover to loosen up the gunk
that has accumulated in the connectors. While they are still wet,
use a soft (baby) bottlebrush to clean out the connectors. Be
careful not to lose the ‘O’ rings or rubber seals. Once the
connectors are cleaned and extremely dry you can re-install them
in their proper positions.
Dicorotron Housings
Ozone contamination on the Xerographic Photoreceptor belt is
caused by ozone gas settling on the belt, under the Dicorotron(s),
when the copier is in the stand by position. Changing the
photoreceptor belt will not fix the problem because the
Dicorotrons are contaminated with ozone gas and will recontaminate
the new photoreceptor belt. It is imperative that all Dicorotrons
be replaced so that recontamination will not occur. Depending on
what configuration of Dicorotron housings you are using it is
important that you replace them with the same type of Dicorotron.
There are two Dicorotron housings in use: They are as follows….
White housing assembly 125K1081
Yellow housing assembly 125K1450
It is strongly recommended that you never wash any Dicorotron
housing with any type of liquid whatsoever. Once the Dicorotron
housing has been exposed to ozone gas, it will become contaminated
forever. Washing or trying to clean it will not fix the deletions
from Ozone contamination and will most likely wash off any
reflective (black) paint on the inside of the Dicorotron housing.
And it will contaminate any new belt you install on the Docutech.
Dicorotron Shield(s)
The Dicorotron shields can become contaminated from ozone gas and
once contaminated they are hard to restore. A technician from Long
Island (NY) suggested the use of a cotton swab (for his 12-gauge
shotgun) to clean the inside of the Dicorotron shield (55K10311).
The diameter of the swab was good and the cleaning seemed to work
just fine on the new stainless steel shields.
Final Reassembly
Once all components are examined, cleaned or replaced for
contamination, re-assembly can begin. Make sure that all fittings
and connectors are firmly connected to ensure proper vacuum on the
Ozac system. I think the key element is to make sure the system is
completely tight and secured. Things like the little white plastic
hose clamps are replaced with hose clamps of equal properties
(plastic) and are securely in place. In a pinch I have had success
with using plastic ty-wraps until I could replace the clamps with
the real thing. Check, and re-check your work as you go along to
insure best results when you finish.
Ozone Blower Continuous Run Kit
Of all the problems that are directed to me, ozone deletions rank
there in the top ten percent of inquiries. Most technicians and
self-maintenance customers deal with this phenomenon in their own
way and some have actually fixed the problem on their own.
Networking is critical in this field and I encourage people to
communicate with others in the field with common problems for
solutions. Overall, ozone contamination continues to be a big
problem in the field and many photoreceptor belts needlessly end
up in the evening trash barrel.
In a recent conversation with Danny (a technician from the
Midwest) about ozone deletions, he mentioned that he had that
problem with a Docutech and when the photoreceptor belt was
removed from the machine, he carefully wrapped it up in the
original packing material and stored the belt in a back room.
After two years he had an occasion to use the photoreceptor belt
for a test and found that the ozone deletion had mysteriously
disappeared. The belt was re-installed and dc-951 performed. This
Docutech is still running on that same belt. It surprised me when
we spoke about this, but placing this photoreceptor belt in deep
storage for a long time may have cured the belt of the ozone
deletion. Hey, it’s worth the effort to try to save the belt.
Thanks Danny.
After the printer has been re-assembled, we can turn our attention
to a Continuous Run Kit that will keep the Ozone Blower motor
constantly on when the machine is powered up. This retrofit was
designed by field engineering and is the only official fix for
deletions. United Laboratory approved retrofit kit number
600K42550 as an electrical wiring fix to keep the blower on at all
times. It is strongly recommended that no home remedy be used to
cheat the blower motor so that it remains on all the time. Before
you install this kit, read the instructions twice and make sure
you have all the tools, and supplies necessary. Oh, and one more
point; do not forget to turn off and unplug the copier / printer
before you start the retrofit.
When all work is completed and the new photoreceptor belt has been
installed you must run dc-951 to set up the new belt with the
system. If you have any questions or concerns about the
installation of the 600K42550 kit, please e-mail me at
Villagecopierny@AOL.COM
. I will be happy to help in any way I can. or call Xerox parts
center 1-800-349-2496. Have your credit card handy.