C6500, quality problem only on black AND heavy paper

[Ab_NL]

Several engines have the problem of smearing black toner only on heavy paper (>250 grams).
Sometimes the problem appears at the first print and then disappears, in some cases it appears after the second or third print and stays on it.
This seams related to the new type of drum (DU104) combined with the new firmware release 70-GN3.
Settings of the dipswitches are as recommended by KM.

If you load 250 grams paper in the drawer but make selection as if it is 100 grams, no toner smearing appears.
Replacing the drum with a new one solves the problem temporarily (two days) After two days the problem came back and we exchanged the drums of Yellow and Black.
Replacing the developer and developerunit solves the problem temporarily.
Cleaning assembly and TR unit has been replaced

Changing the AC bias fine adjustment for black form 0 to +5 reduces the problem.

All the above options are temporarily.
I think there is a relation between the new drums and this problem?
Has anyone had same experience?

See sample below.....

Regards, Ab

21172

[Konicoz]

Im new with the C6500 and had C2211-13 errors, I was told to update to V70 and install DU104's, I have had nothing but Copy Quality problems since. Nightmare so feel your pain. Try increase belt line speed to -20, colour registration and FD mag adj. Also set to thick paper mode in user settings - cant remember exactly where that is but I will confirm tomorrow, been running now 2 weeks without problems, thank fk

[Captain Jack]

I am having same issue on a C6000 and a C7000 replaced transfer belt assy., fuser, and I am replacing the developer unit monday, mostly on heavy paper 257 to 300gsm.

[kalindd]

Guys just stop replacing parts.
Actually, replacing the dev unit and drum will probably fix the problem.

Anyway.
Take a look at both pics. The problem is with the distance between drum and developing unit, it becomes too narrow. ( see the 1st pic)
Place tape on BOTH sides of drum unit, like shown on the pic, rotate the dev unit by hand so everything can come to normal in the dev unit. Put everything back and you should be fine.

I actually use the orange tape that comes with the drums. I place two layers one on top of each other.

Good luck.

[Captain Jack]

This is a great tip using the orange tape ! I am just trying to figure out what happens to the machine when the heavy gsm selection is used, and why using 100 gsm would be better to fix this problem. Maybe the developer station motor spins at a faster speed with heavy paper settings and is fluffing up the developer mix causing the footprint to get closer to the drum, and why only on black ? Maybe the replacement bag of developer mix has too much developer in it. I have seen the black developer unit footprint swell up in the center causing a really large area of copy quality, and replaced the unit the next day for this only to hear the customer say they ran all the rest of the day with no problems, and when I looked at the old developer unit footprint when I replaced it , it looked fine ! Do we have some developer units out there where the magnets are shifting or the internal augers are not working right.:confused:

[Captain Jack]

Ok , two days ago I went back to this customer and was going to put some tape on the drum when I noticed there was an adjustment plate with one screw, so I moved the plate at both ends of the drum for max distance from developer unit, than I ran a # 53 test target, the rear looked fine but the front looked light so I readjusted the front plate just alittle and that worked great....no more black smudge.

[Ab_NL]

Feedback from all our installed engines is that using a piece of tape on the drum is doing the case.
Adjustment of the drum is rather undefined and hard to explain to all our tech's.
Thanks for the feedback we got in earlier situations......

Regards, Ab

[kalindd]

Ok , two days ago I went back to this customer and was going to put some tape on the drum when I noticed there was an adjustment plate with one screw, so I moved the plate at both ends of the drum for max distance from developer unit, than I ran a # 53 test target, the rear looked fine but the front looked light so I readjusted the front plate just alittle and that worked great....no more black smudge.

Yes you are right. You can use the adjustment plates, but we are talking about microns here. I would not bother to play around with those plates.
It takes you about 10 secs to place the tape and you are free to go to the next customer.:)

But everyone has choice.

Cheers. :D

[methogod]

that looks like your dropping developer. not possitive, but when my yellow DV UNIT failed it started dumping which looked much worse then your image, but i would check look into that...

i have 2 C6501s running DU104s without any issues....

[Harris]

Guys just stop replacing parts.
Actually, replacing the dev unit and drum will probably fix the problem.

Anyway.
Take a look at both pics. The problem is with the distance between drum and developing unit, it becomes too narrow. ( see the 1st pic)
Place tape on BOTH sides of drum unit, like shown on the pic, rotate the dev unit by hand so everything can come to normal in the dev unit. Put everything back and you should be fine.

I actually use the orange tape that comes with the drums. I place two layers one on top of each other.

Good luck.

Thanks so much for this advice. Tried it and so far so good, you saved my life.