HP LJ4050tn Printing odd marks on page.

[teckkie2003]

I have a Laserjet 4050tn which prints odd 'marks' across the page. It happens intermittently and is not text in any font. It's a circle about an 8th of an inch (3-4mm) in diameter and I can't work out what's caused it and how to deal with it. They appear, perhaps one on a page, and there is not common pattern to them. It's almost like an air bubble has collapsed on the page and marked it.

The user's tell me that they have changed the toner cartridge, but I suspect that to be faulty.

I've cold reset the Printer, and then the Printer and Internal EIO card.

I've run the cleaning process countless times. I've even replaced the fuser unit with a known working unit.

Any thoughts would be greatly appreciated.



If in doubt, chuck it out!

 

[hpwizzard]

My next thought would be to inspect the transfer roller just behind the toner. Is it original HP toner btw. ? I guess the user has checked also for a previous toner leak that might have caused excess toner on the rollers. Another thing it could be is the media itself. Try use some other paper.

 

[jlasman]

I see the same thing from time to time on a LaserJet 4M+.

I feel pretty confident that it IS an actual character. It is perfectly formed and always the same. Out of context, I would say that it is a degree symbol, but it could be a lowercase "o". It is perfectly round.

Jim Asman
jlasman@telus.net

 

[jtymabel1]

i have seen that defect in other machines. i believe its called fish eyes..its common with remanufactured toner. its caused by contamination in the toner hopper or the toner itself.