CP3525 - marks on paper - where to start?

[wny2016]

I have a very low-print count Color Laserjet CP3525 that a client gave me a few years ago when the dreaded 59.F.0 error popped up. I guess his IT guys thought it wasn't worth fixing. I  hauling it in (very heavy!) and stuck it in an unused corner of my studio, where it sat for a couple years.

Lately, after a short afternoon of unscrewing, unplugging, fixing the sticky sensor and putting it all back together - voila - a perfectly functioning Color Laserjet. I ran it for a while, noting that the Black toner warning  is at 300 or so copies. The first couple pages out of the printer show vertical black marks running the length of the page, maybe 1/2 inch wide or so. I cleaned off the edges of the transfer belt and wiped off some stray black toner I saw inside the machine. If I now run the printer, it produces fairly clean copies after a few faulty ones with the vertical lines/marks. 

If I leave the printer idle for a few days and try to print again, I get the same problems - which always diminish after I've run maybe half a dozen pages. I tried producing and running the cleaning page, which seems to help a bit. But I'm now trying to fix the problem permanently - where to start? I have a spare new HP C504X black toner cart. I have seen references that say after a toner cart gets fairly low, it might tend to leak, as the seals eventually fail. The fuser kit is another possibility - inexpensive to replace. Suggestions?  TIA!

[Repairatrooper]

If you have a cartridge problem you would see marks or toner on the green drums when you examine a cartridge. More commonly this issue is caused by either the secondary transfer roller (rarely) or by the transfer belt (very common). Due to design shortfalls, toner fails to move from the waste collector on the end of the belt into the waste toner bottle. Once too much toner builds up it gets pushed back out onto prints causing the lines you see. The challenge is, if left too long, the thin plastic cleaning blades get deformed and toner will continue to leak out, even if you manually drain the waste collector on the end of the belt. Clean to container, if that does not resolve the issue, you can purchase a replacement collector on Ebay and change it out.

[wny2016]

Thank you - very helpful. Typo: "Clean to container" - ? What is the exact name of the "waste collector" you are referring to? Is it the little plastic bottle? The one in the printer is about 1/3 full. The CP3525 uses CE254A (504A) Waste Toner Bottle - is that what I should replace?

[Repairatrooper]

Sorry, thought it was clear, on the end of the transfer belt that goes into the printer first is the collector where waste toner cleaned from the belt gets dumped, which is then supposed to be move into the waste toner bottle. Often the toner does not move from the collector on the belt to the waste bottle. If you remove the belt and carefully open the little shutter on the left front of the belt (over a garbage can) likely toner will run out. You need to remove as much of that waste as possible. Holding the shutter open while gently shaking the belt will help. You may also need to play with the small gear on the right front of the belt, flicking it back and forth, to get all the toner out. Wear gloves, because any finger prints on the belt will cause defects.

[wny2016]

Thanks for clarifying that - but I'm still really puzzled after looking at the transfer assembly. When you say, "left front" of the transfer belt assy, I am having trouble figuring out which "end" of the assembly is the "front". If I remove the unit from the printer, is the "front" the end that was furthest away from me when I was sliding it out? Or is the "front" the end closest to me when I am sliding it out?

I know this sounds pretty stupid, bit I am not seeing anything that resembles a shutter. When I initially removed the transfer belt assy, I saw a line of toner residue running down the belt itself along the long edge, about 1 inch in from the edge. I removed that with a lint-free wipe.

[Repairatrooper · Accepted solution]

These two photos should clarify the entire thing.