View Full Version : KM c6501. Poor Halftone quality.

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09-27-2010, 05:54 PM
This is regards to KM C 6501.
We are facing problem with CMYK Halftone, while printing the tones at 100% the halftone seem to be very faint and not as per the mark. The halftone quality looks like as if it is printed at 50% coverage.

Total count is 00143040. Drums,Developers and Charging corona are out of life. All the Drums and Charging Corona are replaced. Cyan Developer unit and Developing powder was replace a month ago. For test purpose new Magenta Developing powder was replaced. Calibration done after changing these consumables. All the CMYK halftone were printed at 100% coverage. The halftone quality is the same as it was. No improvement on the quality.
I am thinking to change the transfer belt unit or else the CMYK transfer rollers and the second transfer roller.

Has any one faced this type of problem.
If any feedback on this problem will be appreciated!!


09-28-2010, 04:38 AM
Not to nitpick....but just to make sure....

Was the toner density initial performed BEFORE anything else right after new developer powder was put in?

Or my personal favourite....ensuring that the counters were reset before doing the new developer and drum peculiarity settings?

You may be forced to start from square one and restart ALL the dev units. It sucks and it is expensive, but it may be the only recourse.

The transfer belt is typically replaced at 200K, but this is not set in gold. I have some customers who have gone well past that and are still happy with the quality output. Replacing the drums and charge wires are more often than not the majority of issues we see, but those should be replaced at 100K intervals, as more often than not, they seldom live past this regarding quality.

09-28-2010, 10:29 AM
Thank you for your feedback.
The Counter for Drum and Developer was reset.Toner density initial performed after new Drums installed.
I totally agree with you on the the transfer belt.
Well, I have to clean all the Electrical connector with ISO proply related to consumables.

09-28-2010, 09:15 PM
did you make auto gamma adj. and printer gamma adj?

if you print test pattern 53 with 100 or 130 values (sepately for every color), how the prints look?

10-15-2010, 08:12 AM
Dear All,
Sorry for late reply!!
Well, now my machine is working fine!! Problem is solved after cleaning all the electric contacts.
Thank you very much for your support.

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