large vertical streaks on paper

[GilTaylor]

I have an HP Color LaserJet 2600n and it has worked great for years with no problems.  It has been used infrequently during that time.  a few months ago, I noticed that the printing quality had deminished and that vertical lines about 2" on each side had appeared.  The lines became progressively worse fairly fast.  The black cartridge ran out and I replaced it with a new genuine HP cartridge, but the lines didn't disappear.  

I could see the tonner on the transfer belt and tried cleaning it up.  I also noted that the blue cartridge door didn't always close when I opened the door to the printer.  for some reason it was getting stuck open, but i fixed it and it seems to close every time, but the streaks remained.

If I clean the tonner off the transfer belt, the streaks go away for about 3 pages then return.  I have tried the trouble shooting steps of shaking the cartridges side to side and doing the auto clean and align functions, but no changes.

I am out of ideas, can anyone guide me here?

[davidzuts]

If the issue goes away for 2 pages after you clean the transfer belt that would indicate toner cartridge issues still. The toner can only come from one place and that is the toner cartridges. See if you can tell what color the lines are as it could be cyan which is also dark. The way the printer works is the transfer belt only provides a different charge to the back of the paper as it moves up to move the toner from the cartridge drums to the paper. The way the belt gets toner on the edges is after the paper has passed the belt picks up residual toner left on the toner drums. That toner on the belt is supposed to be removed by depositiong in the lower toner cartridge (I think magenta) waste toner bin). Knowing this it is possible the magenta toner bin is full so the excess toner is not removed. Keep in mind toner lines on the belt on the outer edges is normal as you have to place a sheet of paper on the belt to see if the lines are on the paper or outside the paper ends. If outside the paper ends, the issue is then definitley one or more toners.

[GilTaylor]

thank you for your reply,

I notice tha two of the tonner cartridges indicate a much lower amount remaining then the new or one of the others.  I am not sure which ones.

How do I check or empty the tonner bin if full or is it part of one of those cartridges?