CM4730 Issue

[Bigjimfanning]

I have been working on an HP CM4730. About a month and a half ago one of my techs installed a Fuser and Transfer Belt. Recieved a call about 3 weeks ago that the machine was printing in Greyscale and jamming at the Fuser. Sent my tech out and he said the Fuser was bad. Replaced Fuser and the machine started working just fine. One week later received a call back that the machine was printing in Greyscale again. So this time I went out thinking this might be a toner. I swapped one of them at a time but this did not fix the issue. After putting the old cartridges back in (ending with Magenta) I ran a test print with the old cartridge in there and then suddenly it jammed at the fuser but the page in the fuser suddenly had color on it. Removed the paper from the fuser and toner was easily wiped off the page.

I have been having a defective problem with the 4700 fuser’s lately so I installed a Fuser from a different vendor to make sure I wasn’t dealing with it a defective product. When I put the fuser back in, the machine started printing beautiful pages as normal. I ran about 40 test prints through there and didn’t have a single jam or quality defect. Received a call this afternoon that the machine started printing in Grayscale again, jamming at the fuser again and the toner is not fusing properly to the paper.

Can anyone give me insight into what else this could be? My first thought is possibly a low voltage power supply. Any direction you could give would be much appreciated.

[Copier-Pro]

Hi I would like to assist to the best of my ability to solve your problem.I hope the information i supply will be of help.

I had a different model machine with the same symptoms a while back.Maybe make sure that the high voltage contact springs is not deformed on the board side as well as the toner cartridge side.At the end i replace the high voltage board on the machine,but if i remember correctly it was a all in one board.Low and high voltage on one board.Hope this will solve the problem.

[Valsimot · Accepted solution]

Regarding the grayscale issue, I would replace a transfer belt from a working machine and leave it for testing purposes.

[Bigjimfanning]

Thanks for the info. I did replace the Transfer Belt with a new one and it is still reverting to Greyscale. When I put a new Fuser in the machine, the color comes back but only temporarily (maybe 1 week) The missing color always conisides with the Fuser suddenly failing to fuse the toner.

[Bigjimfanning]

Thanks so much for the info. My suspicion was leaning towards power supply issue so this is where I will start. I will let you know what I find. Out of curiosity, what was the model of printer you were having your issue on? Was it a LJ 4700?

[Bigjimfanning]

So, I went back out again today and noticed a couple of things. First, I checked Tray 3 and noticed that the feed roller was really worn. 2nd, I examined the Transfer Belt and noticed a tear on the right side. I had one with me just in case so I replaced. Replaced the Feed Roller and printed about 50 pages through the machine without a jam or color loss. Here’s what I think was happening:

Due to the tear in the ITB, I think the machine was reverting back to greyscale. I think the jamming at the Fuser was caused by the worn roller. The first page picked up fine, making its way through the paper path and stopping at the Fuser at the same time as the roller in Tray 3 was attempting to pick up the second sheet. Because it was worn it didn’t pick it up properly causing a phantom paper jam and erroring the machine. This caused the first sheet to look as if it was stuck at the Fuser but really had never entered the Fuser because of the second page mispick. Hence the reason for toner being able to wipe right off of the page. This makes sense because when the client would print one page, it would print with no problem. However, if they printed 2 or more the machine would jam and lose color. Thanks so much to both of you for your input even though I don’t think it turned out to be a power supply after all. Only time will tell for sure but it is running great for now.