Bob Larter wrote in message
...
N_Cook wrote:
ie the normal paper or dust slight scratches , not down to the metal
drum
from loose screw or swarf. All quite normal for any OPC.

It's perfectly normal for the OPC to have mild scratches on it. As long
as it's not down to the metal. (Which will give you white lines along
the print.)

Usually this is ok
but the original toner for this m/c not available, requiring second 1
only
source, supposed compatible, formulation. Very fine scratches seem to
hold
the toner , ie exposed bits of latent image retain the toner in the
scratches and so deposit as fine lines on the paper.

That's more likely to be due to dirt on the laser window. Give it a wipe
& a blow. A stray hair stuck in there, or in the laser window of the
cartridge will give you a line down the page.

If too much toner
passed to the OPC then more and more lines appear, so only possible to
produce grey rather than black output. The ac cleaning voltage is now at
maximum of 2.5 KV but some lines are still present with a grey image
rather
than black.
Anyone happen to know what needs adding to the toner to make it less
sticky
or whatever ? or some other procedure. I'm assuming the narrow scratches
are
physically holding the toner but thats only guessing really, decreasing
the
transfer voltage of course produces a lighter image and still transfers
the
lines, so not an option.

There's nothing 'sticky' about the toner. It adheres to the drum from
electrostatic attraction only. If it's sticking to the drum when it
shouldn't be, there's something wrong with the HV, or the IR laser or
cleaning light is not wiping the charge from the drum as it should.

Physically cleaning the OPC or leaving the background heater on all the
time
makes no difference. I'm wondering if the toner is too oily and
decanting to
a tumbler with blotting paper lining would remove some of the oiliness,
before returning to the hopper. Anyone know of a test for oiliness that
gives some sort of numerical result ?

Dry toner is *never* 'oily'. It's micron-sized particles.

Incidently anyone know what the marking B stands for, on the preset for
adjusting the 200 to 250V dc voltage of the OPC relative to frame and
what
this voltage is called ? The other presets are marked TR for transfer
and AC
for the ac cleaning voltage

'B' = Bias.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------


This is a conventional copier, not scanner/laser.
Silicone oil wick/baths at the output have not been used on photocopiers
since the days of sliding top ones, relying on silicones added (sub 1
percent) to the toner instead, not enough to appear oily to the touch but
enough to make sure paper does not stick to fuser drum or silicone rubber
pressure roller. The first one I came across to fix, was wet process toner
in paraffin carrier, 1970s vintage, paper on a roll and a vicious
guillotine.

The toner these days is mainly carbon/charcoal black but also such as
styrene ,styrene acrylic copolymer, polypropylene,metal complex dyes,
methylmethacrylate,styrene butylarylate, silicones and oleic acid