KM C8000 Bent Corners and Jamming Exiting Fuser

rwyeth

Member
I picked up a Konica Minolta C8000, perhaps that was a mistake. Although, I have no complaints of the image quality or feeding of heavier stocks. Naively, I thought I might use it for my color NCR work. But, I can't seem to get it to feed Excel One NCR or any lighter paper without issues. What happens, consistently is that the left leading edge of the sheet will get folded as it leaves the fuser and enters the exit rollers. When the press stops, the paper entering the fuser looks perfect; so, I'm certain it is an issue leaving the fuser. At first, it would jam every sheet, the sheet would be accordioned shoved into the fuser exit. I've cleaned the separator claws, swapped the lower fuser belt assembly with a spare, inspected the exit guides and cleaned it all with rubbing alcohol...none of that worked. Finally, I reduced the fuser temperatures as far as I could and slowed the press down. That seemed to have fixed it for about 300 sheets. But, it's back at it with randomly folding the corner of the leading edge every few sheets or so. It seems like, perhaps, the paper curls enough coming out of the fuser that it causes the issue? I've also tried running the paper landscape...didn't help. Is it a lost cause? Would insanely expensive Xero/Form NCR solve the issue? Also, the paper is stored indoors with relatively low humidity. Please help...
 
Just a thought, How much gripper do you have on the actual printed sheet? If you have a lot of ink coverage close the edge it can cause problems on thin stock. Try running with at least .25” margin.
 
Just a thought, How much gripper do you have on the actual printed sheet? If you have a lot of ink coverage close the edge it can cause problems on thin stock. Try running with at least .25” margin.
That's a good thought. Heavy coverage may make the problem worse; but, it has the issue with virtually no coverage.
 
@rwyeth not wanting to be the bearer of bad news, however you should face reality here - the C8000 has widely been regarded as KM's greatest lemon for a long time. There is plenty of content on this forum and elsewhere about it, here's just one such discussion.

The machine is well over 12 years old now and KM took a remarkable leap when they replaced it with the C1060 (circa 9 years ago), the evolution path then went C2060, C3070, C4070.

Don't spend any money/time on it, as it would likely become a bottomless pit. Hopefully you got it very cheap, I'd be inclined to offload it and pick up one of the newer machines through the dealer who will supply the all vital CPC contract.
 
@rwyeth not wanting to be the bearer of bad news, however you should face reality here - the C8000 has widely been regarded as KM's greatest lemon for a long time. There is plenty of content on this forum and elsewhere about it, here's just one such discussion.

The machine is well over 12 years old now and KM took a remarkable leap when they replaced it with the C1060 (circa 9 years ago), the evolution path then went C2060, C3070, C4070.

Don't spend any money/time on it, as it would likely become a bottomless pit. Hopefully you got it very cheap, I'd be inclined to offload it and pick up one of the newer machines through the dealer who will supply the all vital CPC contract.
@Ynot_UK Unfortunately, I have come across a number of such opinions of the C8000. I probably should have spent more and gotten something a little newer. But, I made the effort to get it, install it, and do a little electrical upgrading to run it. So, with the service manual, ebay, and my willingness to work on it, I'm dedicated to run the thing for at least a little while.

If only I could get it to reliably feed thin stock...
 
Hi @rwyeth , I used to sell production gear for KM, and unfortunately I agree with @Ynot_UK - it was their most problematic machine. That being said, I had several customers who loved it, and the shop I now work at even had one when I first started and it worked 'mostly' ok for us. So all is not lost.

As for your bent corners, we had that occasionally, and there are two possibilities that come to mind. One is that there may be a tiny piece of paper stuck somewhere that the sensors aren't picking up. But since you said you tried landscape and portrait and it still happens, that tells me one of the plastic plates along the paper path is just slightly out of alignment. It could also be that one of the accessories is not perfectly level to the rest and the paper is hitting the edge as it passes from one accessory to the next. It would actually be more helpful if you were getting jams because the jam code tells the tech exactly where it's jamming. In your case, it's going to be a but of a hunt to find the spot that is causing this issue. Hopefully you don't have a long train of accessories! If you do have other finishers with output trays on the top (such as the FD or SD-506) then try having the job output to one of those top trays. This could help determine if the corner fold is happening in the FS or elsewhere.

One side note about what @Ynot_UK said regarding the replacement model, it was not the C1060/C1070 series. That replaced the C6000/C7000 series. The C8000 was replaced by the C1085/C1100 series, then the C6085/C6100. We jumped from the C8000 to the C6085 and love it. However, when our volume started increasing and we needed a 2nd color unit, those were no longer available and we had to get latest generation called the C7090/C7100. This has been a problematic machine for us and can not recommend it.
 
@jwheeler Thank you so much for the help and encouragement. I am really convinced that it occurs exiting the fuser. When I first tried to run the machine, it would jam coming off the fuser almost every time. That is when I cleaned the separator claws, played with the fuser exit roller pressure, thoroughly inspected that area, etc. If a sheet made it past the main body, it was good (except the bent corner); but, more often, it would be accordioned into the fuser exit guide/roller assembly. It seems that the leading edge just doesn't want to feed through the exit guide from the fuser (paper curl is my guess, or sticking to the fuser?) It seems that it is not before the fuser because the image is there and fused under the bend. Adjusting fuser temps and paper settings has helped; but, it still bends corners every few sheets. I actually just ran a short job of a few hundred NCR sheets; and, it only barely bent one corner. This is after I messed with the dehumidifier settings of the paper tray...time will tell... I plan to switch from Excel One to Superior with my next NCR order; and, I am thinking about replacing the fuser exit guide/roller assembly. Hopefully that works.

I am fairly new to printing; it is a side gig for me at this point. If I can keep this C8000 running long enough to expand my offerings and grow a bit; then I will look into spending more on something newer and known to be more reliable. What year did the C6085 come out?

PS. The only other issue I have had was a bit of grinding from the toner supply system. I pulled apart what I could and vacuumed out some excess black toner; hopefully that problem stays away for a while.
 

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