MPC 7501, banding in all colors (CMYK).

[Staffan]

Hello.

I have a problem with a Ricoh MP C7501.
The machine has about 200,000 in color and 50,000 in the black.

I get banding in all four colors.

I go into the SP2-109-2 Select Pattern and choose 100% Coverage.

Then I set these values:
SP2-109-05 Density: K to 15
SP2-109-06 Density: M to 0
SP2-109-07 Density: C to 0
SP2-109-08 Density: Y to 0
Enters the Copy Mode, choose Color, choose A3 (with coated paper), running an A3 with 100% coverage.

Proceed as with all four colors by changing the density so that I only get one color for each PCU.

Each paper look the same those first 48 mm, perfect coverage.
Then starts banding...!!!
The banding don´t show any repetitive/periodical/recurrent patterns.

I have changed these parts in all four PCU / Devunit:

Developer.
Drum.
Both CL-Blade
CL-Brush.
Coatningbar.
I have cleaned Dr. Blade.


I have changed these parts in the Image Transfer Unit:

All four Image Transfer Rollers.
Paper Transfer Roller in the ITB Unit.
The cables from the Transfer Rollers down to the Power Pack.
The actual Powerpack.
Bearings on both sides (and therefore cable from Paper Transfer Roller to PowerPack) of Paper Transfer Roller in the ITB Unit.
Both CL-Blade.
Both CL-Brush.
Coatingbar.


I have changed these parts in the Paper Transfer Unit.

Paper Transfer Roller.
Coating Bar.
Both CL-Blade.
Both CL-Brush



Now I'm out of ideas, what can cause this.
Maby the paper starts to go unstable when it comes over to feed between Paper Trasnfer Unit and Fuser-unit.
But is not 48 mm between Paper Transfer Unit and the feed after that, it is too short.

I'm more into that the Power suply Board can not provide enough power to the BIAS-rollers in the developer unit and / or Paper transfer Rolers.


All modifications are made, it's newest software.
Please, is there any ideas!

[zames77]

We'd really have to see an image to give you any decent help, otherwise we're just guessing at what might be the cause. Can you upload the image?

[stu]

Hi can you post a sample pic? Having similar issue, banding in mainsscan direction, looking likes the dev units in my case,

[Eric1968]

Don't think it's a Power Supply issue. There are some issues regarding image quality and toner scattering. Engine and System firmware should be the latest versions. I have a few bulletins, but unfortunately they're in Dutch.

[TonerMunkeh]

Looking at the list of parts you've fitted to the PCU's you haven't mentioned that you have replaced the charge roller assemblies on the colour PCU's. Are you only getting banding on CMY or black too? If it's just CMY it could be the charge cleaning rollers have broken down.