Drum cleaning

[R. Levor]

FYI-
A few weeks ago I asked about getting remanufactured drums for my
Brother HL5140. Then I decided, nothing to lose, and I tried cleaning
the drum with denatured alcohol, and I rubbed it pretty hard. Came out
great, no more spots on printouts. So it's worth a try.

Bob

 

[Arthur Entlich]

A few cautions.

There are many causes for spots on laser printer drums. Some are just
transfer of hot toner or developer that fuses to it. This shouldn't
happen, but with double sided printing or other design flaws in
printers, sometimes fused toner can get stuck to the drum. Sometimes
it's contaminants that were on some paper, like glue or jelly from a
sandwich you were eating ;-) if you reuse paper.

However, there are other causes. Scratches, or pits into the drum's
photosensitive surface can pick up toner. Cleaning can help with this
but they come back shortly. A drum that is failing may begin to give
low contrast copies and increasing the darkness of the print may make it
passable longer, but defects are more likely to show up from any flaw
on the drum. Toner spillage from the toner cartridge, developer, or poor
clean up of the drum due to a bad wiper or excess waste toner removal
system failure (due to being overfilled etc) may cause random dots or spots.

If you do decide to try to clean the drum, here are some suggestions:

1) Only work on the drum in low light conditions, they are light
sensitive and bright full spectrum light or UV can permanently damage them

2) Make sure to use a non-abrasive rag so you don't scratch it up. If
possible handle it wearing cotton gloves, or gloves made of plastic that
are non-abrasive and not coated with anything that may transfer to the
drum.

3) Be very careful with the solvent you choose. Not all drums have the
same surface, and some may be permanently made useless if you use the
wrong solvent. Denatured alcohol may be safe for some, but always try a
very small location on the very edge of the drum first and allow it to
sit to determine if it will dissolve, craze, or soften the drum's surface.

DO NOT use acetone, as it will dissolve the surface of many types of
laser drums.

4) Some drums may seem to be "fixed" after cleaning but will rapidly
fail or decline after cleaning with a solvent because they may have a
special surface coating that was removed by the cleaning process.

Ultimately, cleaning of a drum should probably only be considered as a
last effort if you are set to replace it otherwise.

Art

 

[Bob L.]

I appreciate the tips. It was indeed a "last effort." So far so good.

Bob L.

 

[Davy]

I would have thought if there was any unwanted blemishes on the prin
and they are in the same spot time after time then one could assum
it to be the drum

If the blemishes are 'not' in the same place print after print then
would be looking elsewhere

If there is toner spillage for example or toner dust anywhere in th
vacinity, this is more than likely to be picked up by the charge o
the drum and produced as unwanted blemishes, these will not be in th
same spot every time

The coating on the drum is only microns thick, as Arthur say's grea
care needs to be taken that this is not impaired

Just my way of thinking which seems logical

 

[Tony]

FYI-
A few weeks ago I asked about getting remanufactured drums for my
Brother HL5140. Then I decided, nothing to lose, and I tried cleaning
the drum with denatured alcohol, and I rubbed it pretty hard. Came out
great, no more spots on printouts. So it's worth a try.

Bob

For clarification if anybody else has this sort of problem....
The vast majority of monochrome laser printers have several rollers (usually
the drum and 2 rollers in the cartridge and/or drum unit, and generally three
rollers in the printer itself) which can produce blemishes on the output due to
defects on the roller. These defects can be as simple as some toner stuck to
the roller which might be able to be cleaned off or as serious as physical
damage or wear which necessitates the replacement of the offending part.
In just about all printers of this type (monochrome lasers) such defects will
repeat on the page and the distance between each blemish usually allows the
technician to precisely determine which roller is at fault (distance between
blemishes equals roller circumference) this is called a repetitive defect.
These defects can be dark or can be absence of toner depending on which roller
is at fault. The defect will always be the same distance from the side of the
page (as it feeds from the printer) but the first occurence will almost always
vary in distance from the leading edge of the page. Cleaning drums with
isopropyl is often succesful although there are some that die when you do it
(organic non-selenium based drums), but the biggest issue is that drums need to
be lubricated with a dry powder conductive lubricant to prevent them from
binding. This is less of an issue with Brother lasers than it is with some
other makes. Not lubricating the drum can result in early permanent drum
failure. In use the toner acts to some extent as a lubricant but the initial
lubrication is an important requirement. Also drums are destroyed almost
immediately by exposure to direct sunlight and deteriorate quickly in any other
sort of light (5 minutes can be enough to permanently damage the drum).
The above applies equally to most colour lasers except those that use an OCP
belt in place of a drum, in that case any defect on the belt will almost always
occur only once on the page and always in the same horizontal and vertical
position, this is because the belts are usually not manufactured as a
continuous belt and have a join. This join is avoided by the printer when
printing so the belt is always in the same position relative to the start of
the page (ie it is between pages) unlike drums which have no join and do not
have this problem. This is why most printers with OPC belts cannot print
banners. Repetitive defects on lasers with OPC belts follow the same rules as
for lasers with drums except for belt defects.
Tony

 

[Arthur Entlich]

Those drums require several full rotations to print a letter size, so
blemishes may repeat several times. Those blemishes may change location
relative to the paper, although they will tend to be in the same place
relative to one another. Some types of toner "spills" or excesses will
show up at the same location on each page, as a horizontal line, for
instance. Some laser printers have poor toner removal systems that clog
or back up and redeposit toner on the drum. If the wiper blade which
cleans the drum of excess toner as it turns, is not working well, it may
leave a pattern on the drum also, that can be either random or more
regular.

Art

 

[Arthur Entlich]

Some great and valuable information, Tony. Thanks

Art