MPC6000 - Halo Effect

[E Winter]

Hi everybody,

I've a customer who's complaing about the halo effect on this machine. We tried the service bulletin (RTB18) but that doesn't helped a lot. The effect looks worser than on the images wich are included in the RTB btw. There's also a note that this seems to be a limitation on this machine so I don't really expect an "official" solution

We tried to run the machine with a fiery (together with a ricoh tech) - same issues, just more ways to work around it. Finally the only way to reduce the effect to almost zero is setting the printmode to a more or less "rough" print/dither pattern.

Unfortunately the quality is not acceptable in these mode because you'll get ugly moire effects. And on the other hand you have to deal with "halo" if you print with hq dither and smooth half-tones.

Well, any ideas besides swapping to an other machine?

[stephend]

MPC 6000

"This symptom is most visible when text is overlaid onto halftone areas as mentioned in the modes in
SYMPTOM. The greater the difference in image density between the text and halftone area, the more
noticeable the halo effect is.
This symptom is also noticeable to the user when the mode is changed to 2-bit mode. This is because the
default dithering pattern for 2-bit mode is designed to improve gradation, but makes the halo effect more
visible." from Ricoh bulletin that desribes the problem

Solutions to reduce the Halo effect:
1. print using 1 bit mode 600x600 (Default is 2 bit)
2. Change the dither pattern used in 2-bit mode (1800x600dpi).
3. Update the firmware to the latest version
4. Clear memory for the printer application (note that gamma curve will be back to default after this)
5. Reboot
6. Access SP (Printer) 1001-002 and press key 6 and then #
7. Exit SP mode and reboot
8. Run ACC Test pattern 2 (1800x600dpi)
Good luck!

[stephend]

an extra question

No banding in the midtones?
No marks on the carge rollers?
No pre-transfer problems...yet?

Ricoh has a conductive grease (specially designed for this model) that will improve the overall quality used in conjunction with other counter measures.
I'm figthing with this machine since day 1 and I can tell you that it's a real battle.

[E Winter]

No banding in the midtones?
No marks on the carge rollers?
No pre-transfer problems...yet?

Nope - we have just a few in the field and none of them is running in a real high volume enviroment so I guess I have to deal with these issues with a little delay. But thanks for the warning - I'll keep that in mind

You've quoted the technical tip I've already tried - the symptom was a bit reduced but quite far away from beeing satisfying - and the customer wasn't pleased with the decreased gradation.

[stephend]

MPC 6000

Then I will replace the pre-transfer rollers. Ricoh replaced the first production batch with a new type bigger in diameter. The units affected are
MODEL NAME SERIAL NUMBER
Gestetner MP C6000
Lanier LD260c
Ricoh Aficio MP C6000
Savin C6055

with serials:
M79803xxxxx

and
Gestetner MP C7500
Lanier LD275c
Ricoh Aficio MP C7500
Savin C7570
with serials M80803xxxxx

The procedure mentioned yesterday + pretransfer roller + conductive grease + new PCU unit + newest firmware + latest patches for Fiery did an improvement on our machines

[E Winter]

Thanks again!

Well, we told the customer that this is a "limitation" - he's running the machine within a trial period so he can decide to keep it "as is" or give it back. Of course we can try to swap misc. expensive parts but I don't see more than just a little chance to solve the issue. Of course I will take care to follow the tip with the conductive grease in the future.