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907tec
05-31-2012, 06:20 PM
Looking for a little help in fine-tuning some thick-paper settings, as I don't have much experience in that dept. I have a customer that is attempting to use 80lb Cover Paper (Smooth Finish) through the bypass on their Bizhub C451. According to the box of paper, it is equivalent to 215gsm, which should be within spec for the bypass tray. The only wildcard should be the coating/finish, which I am unfamiliar with. Anyways. Even after setting the tray to Thick 3 and setting the Thick Paper mode to "quality", they are getting faint black streaks on their prints.

I am unable to recreate the defect using regular weight paper of any size, also not getting the defect using 8.5x11 80# cover. When making copies of an 11x17 color sample on the 80lb Cover, I get light grey streaks running in direction of paper travel at 1" from trailing edge. I have tried various settings for the loop adjustment and the fuser transport speed, but nothing seems to even affect the streaks. I'd love to just blame the paper, but explaining that to this customer would be....touchy.

I have attached a cropped scan of the defect, though it doesn't show up very well. This is a view of the center portion of the trailing edge.








16074

CompyTech
05-31-2012, 09:00 PM
Looking for a little help in fine-tuning some thick-paper settings, as I don't have much experience in that dept. I have a customer that is attempting to use 80lb Cover Paper (Smooth Finish) through the bypass on their Bizhub C451. According to the box of paper, it is equivalent to 215gsm, which should be within spec for the bypass tray. The only wildcard should be the coating/finish, which I am unfamiliar with. Anyways. Even after setting the tray to Thick 3 and setting the Thick Paper mode to "quality", they are getting faint black streaks on their prints.

I am unable to recreate the defect using regular weight paper of any size, also not getting the defect using 8.5x11 80# cover. When making copies of an 11x17 color sample on the 80lb Cover, I get light grey streaks running in direction of paper travel at 1" from trailing edge. I have tried various settings for the loop adjustment and the fuser transport speed, but nothing seems to even affect the streaks. I'd love to just blame the paper, but explaining that to this customer would be....touchy.

I have attached a cropped scan of the defect, though it doesn't show up very well. This is a view of the center portion of the trailing edge.








16074


Try Xfer output fine adj. I don't if you have done that yet but in the past I have had some stuff like that doing dbl sided on thick and reg paper. look on PDF page #351 in the service manual(C351/C450) for more details. Good luck.

Spratt
06-01-2012, 01:44 AM
Hi
Have you tried increasing the fuser temp for thick paper?

907tec
06-01-2012, 01:54 AM
Well...apparently I was fooled yesterday. I was unable to recreate the issue using anything besides their 80# smooth cover stock, but now I can get it to happen on regular-bond paper. Now that it is happening more consistently (and on cheaper stock), I was able to determine that the Black IU is failing prematurely. I know about the lock-lever mods and have them installed, and this IU does not appear to be dumping. Looks more like the cleaning blade isn't cleaning well enough, and possibly some toner crusted on the drum ends to make things worse.

Naturally, I'm out of K-IU's at the moment, so you'll have to wait a couple days before I can update.

Thanks for the help so far, though.

blackcat4866
06-01-2012, 02:07 AM
Hi
Have you tried increasing the fuser temp for thick paper?

I was thinking about that too. On longer runs, thick paper bleeds heat from the fuser towards the center of the roller. The more consecutive prints, the more the difference between the center temperature and the edge temperature. If you do decide to elevate the fuser temperature for thick3, make sure that the edge temperature is not too high which has exactly the same effect as too low of a fixing temperature.

If you don't see the artifact on runs of 12 or less, I'd venture to guess that it's related to fixing temp. =^..^=

JustManuals
06-01-2012, 02:33 AM
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