Fading black prints WC7655

[aca2122]

Hello all,

I have a WC7655 that the solid black areas start to fade out. When it started doing this, I replaced the black developer and housing thinking it was at the end of its life. It printed fine for a couple of days maybe to a week. It started than to fade again. I replaced the K developer bias. Still no go. From service mode if tone up it prints fine than starts to fade out after awhile. I tried replacing the toner sensor, no go. I am at a loss on this. When I do the ProCon the black adc is off which I can correct by tone up the black, but the problem comes back again. The procon printout will have the 100% k box kinda splotchy.

The one thing I did discover is if i run solid black all over the page, it corrects itself. The first couple pages dont look that great, than they are fine. I hear it dispensing toner while doing this.

I have wiped down the MOB/ADC sensor. I'm just at a loss on what it is doing. All of the other colors are fine, black is the problem. I have also replaced the drum as well.

Should I replace the MOB/ADC sensor? If that doesnt work try the MCU?

Thanks!

[Mukasa]

Re: Fading black prints WC7655

[QUOTE=aca2122;531575]Hello all,

I have a WC7655 that the solid black areas start to fade out. When it started doing this, I replaced the black developer and housing thinking it was at the end of its life. It printed fine for a couple of days maybe to a week. It started than to fade again. I replaced the K developer bias. Still no go. From service mode if tone up it prints fine than starts to fade out after awhile. I tried replacing the toner sensor, no go. I am at a loss on this. When I do the ProCon the black adc is off which I can correct by tone up the black, but the problem comes back again. The procon printout will have the 100% k box kinda splotchy.

The one thing I did discover is if i run solid black all over the page, it corrects itself. The first couple pages dont look that great, than they are fine. I hear it dispensing toner while doing this.

I have wiped down the MOB/ADC sensor. I'm just at a loss on what it is doing. All of the other colors are fine, black is the problem. I have also replaced the drum as well.

Should I replace the MOB/ADC sensor? If that doesnt work try the MCU?


Hello
If what ever your have said is true, that you replaced a new black drum catridge still copies fades again then you have to check for the black developer bais.
1. check for the black drum earthing , the drum sits on it at the extrime left if it there and clean.
2. Remove Xerographic Developer Drawer and check by touching or seeing the developer bais housing if broken at the rear of the machine.
3. The developer tanks ATC sensors values should all read the same with that of the NVM of the machine.( mainly black),if there not the same correct them
and perform MAX setup .

Rgds