MX-M850 Low toner density

[Bani]

Hallo,

I have done a PM 100k Prints ago.
Customer say the density is too low.
Now i tonered up the machine and performed 25/2 and made all
quality adjustments.
After 1 week and 20k prints, customer says that density is too low again.
What can I do by the next visit.
Total counter is 2,600k.

Thanks in advance.
Bani

[OMD-227]

When you did the PM, did you replace the dev?
I have tried to extend the dev life on the Hercules machines as a test, but it always let me down about 750K (due at 500K). So replacing the dev every 500K is very important. Otherwise, density drops right off.
Early on I tested if the dev could last the same time as the drum for 1 million, but more often than not, it didnt last... still looked ok, but had poor density.

Does your dev unit have the spring fitted to the MG roller shaft? (picture attached).
Without this modification, the dev bias voltage varies, causing faint, irregular density, at an irregular pitch, especially on halftones.
If your dev unit doesn't have this spring, install it ASAP. Part number is MSPRC3855FCZZ

Also, adjust the transfer control settings in sim 8-20. The 850 Hercules should be set to 40.

Make sure the firmware is up-to-date, as many changes have been made to process control timing etc etc in the newer versions.

[Bani]

Thank you wazza for your quick reply.
Firmware is up to date, and Dev is replacet at PM.
I know this bulletin, but my machine is younger then the bulletin is.
I check the spring at the next visit and let you know whats up with the machine.

Bani

[ren2003]

hey bani did you ever find the solution to this issue? iv'e been having this same issue with some of my MX-M850's that are over 300K. Please let me now. in my case it comes and goes, when i go out to the customer is just do a halftone calibration which fixes it 2 days later the customer calls back with the same issue. any help will be greatly appreciated