Image quality issue Bizhub C658

[JasonSBE]

I'm already sending a tech out in the morning to swap the HV board and DC contacts, but I wanted to put this up here in case there's something else we should be looking at.

The machine presented with image quality issues last week. We swapped the K Developer with one from another machine for testing purposes. It cleaned up and was working right. Now the issue has returned. Same image quality and same symptoms. My tech didn't check the Table values in state confirmation. I ran out there today and noticed that the K values are abnormally high. I put in a new drum and tried to calibrate to see if it would come down, but it didn't really improve. I set the background image density to 5 for K and that has helped the image quality but not the underlying issue. We're going out tomorrow with a new OEM developer, a hv board, and a dv contact assembly in the morning.

samples.jpg

It isn't letting me upload the pictures of the VDC and VG values. Files prolly too big.

Before new drum/gradation adjust:

Plain Paper:
Vcd-c 338
vdc-m 350
Vdc-y 452
vdc-k 800


Vg-C 488
Vg-M 505
Vg-Y 352
Vg-K 800

After new drum

Vcd-c 372
vdc-m 399
Vdc-y 407
vdc-k 771


Vg-C 522
Vg-M 554
Vg-Y 557
Vg-K 996

[Brad6784]

Re: Image quality issue Bizhub C658

I'm already sending a tech out in the morning to swap the HV board and DC contacts, but I wanted to put this up here in case there's something else we should be looking at.

The machine presented with image quality issues last week. We swapped the K Developer with one from another machine for testing purposes. It cleaned up and was working right. Now the issue has returned. Same image quality and same symptoms. My tech didn't check the Table values in state confirmation. I ran out there today and noticed that the K values are abnormally high. I put in a new drum and tried to calibrate to see if it would come down, but it didn't really improve. I set the background image density to 5 for K and that has helped the image quality but not the underlying issue. We're going out tomorrow with a new OEM developer, a hv board, and a dv contact assembly in the morning.

[ATTACH=CONFIG]57267[/ATTACH]

It isn't letting me upload the pictures of the VDC and VG values. Files prolly too big.

Before new drum/gradation adjust:

Plain Paper:
Vcd-c 338
vdc-m 350
Vdc-y 452
vdc-k 800


Vg-C 488
Vg-M 505
Vg-Y 352
Vg-K 800

After new drum

Vcd-c 372
vdc-m 399
Vdc-y 407
vdc-k 771


Vg-C 522
Vg-M 554
Vg-Y 557
Vg-K 996

That looks like an issue with the toner, is it OEM toner or compat? If it was a toner issue, that would also explain why a replacement dev unit cured it for a little while. I would take a new toner, fit it and run sky shots to clear the hopper (or vac it out) and then fit a new dev unit.

Good luck.


Sent from my iPhone using Tapatalk

[tsbservice]

Re: Image quality issue Bizhub C658

Never ever trust used good known developer unit. Period.
Especially black is so cheap to do experiments with.
K voltages are extremely high.
Go for new one. Stock it.

[copyman]

Re: Image quality issue Bizhub C658

That sample is classic example of developer unit being depleted of developer. I swap developer units from other machines all the time with no issues so think you are on right track with HV pwb. Usually when I have a machine producing a sample like that I put new drum and either a used dev unit or add aftermarket developer to existing dev unit. If dev unit life is at 25% or less I will replace with new unit. Especially the black since like tsbservice posted they are so inexpensive.

Also agree with Brad that aftermarket toner could cause issues.

[JasonSBE]

Re: Image quality issue Bizhub C658

Thanks all for the solid tips. The toner may not be OEM. We have been trying to get back to all OEM toner but some sites still have compatible. I'm gonna have my guy check. I know swapping devs is not a good idea, we just didn't have any available at the time. We've had them on order for over a week. Thankfully we're supposed to be getting some tomorrow. I'll try the toner first, and if it's compatible we will vacuum out the sub hopper and try to bleed out the other toner. If it doesn't clear up we'll change the dev. It already has a new drum. If the numbers are still sketchy, we'll try the dv connections and hv board.

[rrrohan]

Re: Image quality issue Bizhub C658

if i see non genuine toner spares at customers that we supplied during the shortage i just bin them as the supplier we used atleast were killing devs and even drum (leaving weird sticky residue on them)

id vote genuine toner after cleaning hopper and new dev

[copyman]

Re: Image quality issue Bizhub C658

if i see non genuine toner spares at customers that we supplied during the shortage i just bin them as the supplier we used atleast were killing devs and even drum (leaving weird sticky residue on them)

id vote genuine toner after cleaning hopper and new dev

I'm also cleaning up the mess that Konica Minolta put us into with the toner shortage last year. After many years of educating my customers to use only genuine toners I had to sell them aftermarket during the shortage. Now trying to get all my customers back to genuine. So far I've been lucky with only a few machines affected by crap toner. I'm still pissed at Kon/Min. If I wasn't so close to retirement I would have switched OEM's, that's how mad the toner and machine shortage made me !!!!