HP Color LaserJet 4650dtn patchy toner on right of paper

[krtaylor7024]

I have an HP Color Laserjet 4650dtn. Recently it has started having missing / patchy toner on only the rightinch or so side of the page, mostly the yellow and cyan. Blue and black doesn't seem to have as much if any problem.

I tried replacing the toner cartridges - no difference.

I saw suggestions that this could be caused by a worn-out transfer belt. Sure enough, about that time the printer warned that the transfer belt was nearing the end of its life. So I replaced it - no difference.

The only thing left that I see would be to replace the fuser, which I can do, but I don't see much suggestion of fuser problems causing these symptoms. But, maybe?

All parts are genuine HP.

Any ideas? It's a real workhorse of a printer and I don't know of any new printer that is nearly as durable, so I really would rather repair than replace if I can.

[Repairatrooper]

Can you post a sample? This model is pretty reliable and the most common issues we run into are print defects related to dirt in the optics of the printer or failing High Voltage Power Supply. Typically fuser failure will result in non-bonded toner, if the rollers in the fuser look clean that is less likely the issue. Also make sure that this device has adequate power. It needs over 12 amps during normal printing and any other large device on the same circuit can result in power starvation.

[krtaylor7024]

Thanks for answering!  Here's a scan of a test print I made.

Ignore the banding, that's a scanner artifact - the important part is the missing colors at the right side of each color bar.  As you can see, it's mostly a problem for magenta and yellow, less so for cyan, and minimally so for black.

The printer is on a circuit with other devices, but nothing of particularly heavy draw.  I think the largest draw on the same circuit is my computer workstation, which is also on its own UPS.  The printer is on an APC pro surge suppressor, but not a UPS.  Nothing significant has been added to the circuit for a long time, since before this problem appeared.

I thought there might be dirt somewhere in the optics, and I'd be glad to do some cleaning, but haven't found anything discussing where exactly those optics are to clean them.  Do you have a guide?

The fuser rollers look generally OK.  In particular, I see no difference on them across their width, and this problem is arising only ever on once side of the paper, so I'd expect that area to look different if that were the problem.

[edit] No matter what I do, the image upload in this message system doesn't work.  The image uploads fine and appears in the preview, but then when I post, it just gives a warning icon.  My "saved photos" are all just warning icons.  I tried both GIF and PNG, no difference.  Is there some other way to do it or is the board just broken?

[Repairatrooper]

By their design, surge suppressors can cause issues with printers. They re designed to clamp down when  large in inrush of power is detected and the 10+ amps the printer draws looks just like a surge. Connect the printer directly to the wall and see if that helps. No picture on your last post. 

Have all cartridges been changed? A bad cartridge (often yellow) can cause a current drain on the high voltage power supply resulting in failure of image on one side.

As for cleaning the optics, the amount of disassembly required is beyond the time I have to post here. You basically have to remove all the laser scanners, open them and clean the lenses and mirrors. If the inside of the printer is not that dirty this is less likely the issue. You can find vendors online selling service manuals that would be a great help and someone may have made a video on youtube showing the procedure.

[krtaylor7024]

I couldn't get the message board to display my image.  Here's a link to another location I uploaded it to that seems to work.

I did not know that about laser printers and surge suppressors.  I took the printer off the surge suppressor and plugged it directly into the wall, and reprinted my test print.  It didn't help.  😞

I have replaced all the cartridges except the cyan since the problem first appeared.  And I'm about to replace that one too.

[krtaylor7024]

Update: The cyan cartridge just ran out, and I replaced it (genuine HP).  No difference.  So, all cartridges plus the transfer belt have now been replaced since this problem first appeared, none of which helped.

You suggested perhaps a power supply issue?  Would that  generally cause a problem on just one side of the paper, rather than randomly or consistently throughout?  I suppose I could probably replace the power board, I've been inside the printer before, though it's not much fun.

[krtaylor7024]

So just to follow up - sounds like the recommendation is to replace the high voltage power supply?  Looks like they aren't really available new anymore, but there are plenty of refurbished ones I can buy, and I found the maintenance manual showing how to do it.

https://www.printerparts-exchange.com/media/custom/upload/Color4600_4610_4650.pdf

[krtaylor7024]

Hello, just wanted to confirm - the consensus is that I should order and replace the high voltage power supply to hopefully resolve this problem?