Bizhub c250i magenta stripes and grainy color

[occus]

Re: Bizhub c250i magenta stripes and grainy color

Last week this customer called me and said he had yellow streaks on the print. In the morning everything was still good and they replaced the yellow toner because it was empty.
When I was on site I could see how the charging roller and the cleaning roller underneath were full of yellow toner. The pattern was like the magenta earlyer. I then put this drum in the magenta slot and was expecting to see a magenta stripes(with 6-7cm) but that wasn't the case.
Only after 15 prints did a few thin stripes become visible.
The drum values were also (still) too high. That's why I replaced the yellow drum. But even with the new drum the print was still not okay... not even after 20 A3 prints for cleaning. Stabilyzer and Gradation with no effects.

Photo of print with swapped drum yellow/magenta. After replacing yellow drum the yellow pattern was still there.
yellow.jpg


During my search I discovered a few fine lines in cyan full pattern and decided to swap the cyan drum too. And then, like a miracle, this yellow pattern disappeared immediately.

Now all the drums have been replaced from the factory, last year the magenta and now the Y+C which had a life value of 59%.
That grain in the print is still present.

The next day I had a call from another customer, yellow toner was replaced and about 2 weeks later there was a slight yellow background on the entire paper. But more about that in the other thread for background. (really interesting information)
Of corse i have only genuine original Toner.

[barber782]

Re: Bizhub c250i magenta stripes and grainy color

I would personally try changing the colour reproduction back to 8 series:
Switch 153 change to Hex 40,
Run Stablisation after and grads

Found that the solids always look really grainy out of the box. had a a lot of customers complain about the colour quality.
After applying this they are happy.

Just a thought.

[occus]

Re: Bizhub c250i magenta stripes and grainy color

already done but with no effect to the grainy print.

[tsbservice]

Re: Bizhub c250i magenta stripes and grainy color

already done but with no effect to the grainy print.

Maybe new fusing units can help
We have yet to see it.

[occus]

Re: Bizhub c250i magenta stripes and grainy color

I thought about that too but the device has no warranty and I have to pay the costs myself.
So I wait until the customer complains or the fuser goes away early.

[REGSIS]

Re: Bizhub c250i magenta stripes and grainy color

Grainy halfone is all about toner from mine experience.
Customers bought "OEM toner" but from their sellers' "another channels" i.e. not from KM.

Those toners caused P-21 and stripes on transfer belt besides grainy halftones. Vd and Vg were raised to 500 and 600V instead 300V and 400V.

You can try to vacuum M toner hopper and put a new OEM M toner bought directly from KM. Run manual tonner add/hopper fill. Raise TCR value for M to +1. After 50 A3 halftones 255 of M you should notice a change and grainy halftone should be gone. Lower TCR value back to 0.

Hope this helps.

[occus]

Re: Bizhub c250i magenta stripes and grainy color

In my case, the problem already existed with the first factory toner. I actually only have contract customers.

[occus]

The story continues...

The customer calls and says he changed the cyan toner in the morning. In the afternoon, there were 5cm wide cyan streaks on the printout, and then soon after, the entire page, including the background.

The last drum I replaced was still at 86% (1 year before) and failed again. The surface of the drum, the charging roller, and the cleaning roller were completely full again. So I replaced the drum again, and the problem was solved immediately. I adjusted the stabilizer and gradation, and made various test prints. In the afternoon, the customer calls again > cyan background.

Now I had no choice to replace the developing unit. I didn't have one in stock, so I used a used one from an old machine. I transferred the toner sensor from the old DV to the used one, and it worked.

I can therefore say that this grainy image quality comes from the DV, because that also solved it.

Finally, I'd like to point out that I've had four customers call me about background or thick streaks after replacing their toner. These are all contract customers who receive original toner from me. Either there's bad toner in circulation, or bad developing units were installed at the factory.

[tsbservice]

I believe they are bad developer units from factory destroying your drums. Will see if can find anything related later.

[femaster]

We have had a number of i-model machines over the last few years with bad DEV units from the factory. Everything seems to be working fine in the beginning, but then when they start getting some pages on them, the drums and charge rollers come out completely wrapped in toner in areas. I've seen it happen with as low as a few thousand pages, all the way up to 30+K pages. You replace the destroyed drum and it works perfectly again for a period of time and you end up with the same toner wrapped drum again. The only solution is to replace the DEV unit along with the drum. There was definitely some sort of an issue with the DEV units, but looking at them you would never be able to tell. We still have no idea what the problem is with them, just that replacing them fixes the toner covered drum issue.

[stronghold]

Hello,

What firmware version is installed?

I’ve had similar cases with the i-series before. In my case, I resolved this issue without replacing the DV unit.

Is it possible to print the full ink fill report (*Level History 1*) from the service menu and send a photo?

The procedure is as follows:
**Service Mode → State Confirmation → Level History 1 → Press Start**.

This print function reflects the complete ink fill status and is crucial for further diagnostics.

[occus]

Hello,

What firmware version is installed?

I’ve had similar cases with the i-series before. In my case, I resolved this issue without replacing the DV unit.

Is it possible to print the full ink fill report (*Level History 1*) from the service menu and send a photo?

The procedure is as follows:
**Service Mode → State Confirmation → Level History 1 → Press Start**.

This print function reflects the complete ink fill status and is crucial for further diagnostics.

Problem ist solved now after change of the DV cyan, Firmware G00-RF