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Photocopier - paper scratches on the OPC

The ps voltage was a bit high but not enough to push the corona voltage from

5.55KV to over 8KV. The preset only varied it a few hundred volts. Put a dropper in line and its now 5.8KV and working , subjectively, just as before - lines on the paper image. But these lines are no longer "burned" onto the OCD. Previously if you removed the corona housing and wire, then the lines still emerged onto the paper for a number of runs because of a build up on the OCD, that failed to clean off with AC and wiper blade. Now if you remove the corona the next output is plain white so the cleaning process can now cope with it. I tried changing the corona housing to a spare one but the lines are in exactly the same place. It is difficult convincing myself that the toner lies in fine lines on the OCD as there is no obvious repeat, coincident with the lines on the paper. There are hundreds of such fine lines with nothing making the most persistently tranferrd ones stand out. If the following makes no difference I will try the earlier OCD that worked fine but the original owner managed to scratch numerous deep lines axial to the drum so produced heavy black lines obscuring the image. If the lines stay in the same position then it will be a total mystery as I've cleaned ,twice now, all surfaces near the OCD path. I should have said these present lines are so fine they are just intrusive rather than blocking information.

Going back to my original thinking, as this all started about coincident with forced change of toner supplier. I made up a test batch of some of the toner mixed about 2 :3 of charcoal sieved down to 75 microns, the thinking is it would dilurte an excess of oil/styrene. It takes a while for this to work through the feed system but so far the ratio of blackness of wanted image to tram lines has improved, I think. I can get hold of styrene and have plenty of silicone oil but how do you mix 98 percent sieved charcoal with 2 percent or so of liquids without clumping? At this rate I may as well try formulating my own toner . My set of old brass lab sieves go down to 75 micron, any ideas for a source of mesh of order 30 or 40 micron?

Reply to
N_Cook
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Jesus. You're sure trying to do this the hard way!

Have you cleaned the laser module window, & tried swapping out the cartridge?

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

from

"burned"

then

cleaning

with

nothing

worked

to

cleaned

the

thinking

to

charcoal

well

75

This is conventional copier with document glass and toner hopper feed. The same problem must apply to cartridge/laser systems for when the original specified cartridges are no longer available and supposed replacement equivalents are not equivalent. Its just that the process (whatever it is) is otherwise going on , unseen , inside the cartridge.

Reply to
N_Cook

I tried the original OCD with the deep scratch lines axial to the drum and there is not the slightest hint of any of the thousands of paper scratch lines on the original, coming through to the paper, just the deep imperfections coming through. That is old OCD with the current toner produces a good black image with no tramlines. I'm wondering if too high a volts/mm in the active layer, from the corona wire being too high a voltage can cause damage. Somehow in conjunction with very fine scratches , give a concentrated charge distribution and very locally damage the germanium or cadmium sulphide or whatever the active layer is. With the problem OCD outside the machine I gave it a very close inspection and I can still not see any correlation between the paper scratch lines that cause tramline output and any of the thousands oif other possible ones.

It is a continuum thing. If more toner is allowed through then more and more tramlines appear. I could understand it if some bits of hair conducted straight from corona to OCD to cause a few permanently affected rings but not this situation.

Reply to
N_Cook

Sorry, I had some sort of brainfart & was thinking that you were talking about a laser, not a copier. You should clean all the mirrors in the optical path, & look for stray hairs or other debris. Your problem is incredibly unlikely to be related to the composition of your toner.

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

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