Bizhub C308 , not enough black

[pinspin]

Hello . We have a problem with the quality of black printing on Bizhub C 308 . We cleaned copier , replaced sub hopper unit , high-voltage power supply unit , developer unit , but after 5K copies malfunction returned . The developer unit has less developer now. We will be grateful for any advice .

[Mitch Barron]

Re: Bizhub C308 , not enough black

have you tried color calibration from service mode? Do you have some examples of the problem? I have found very often that when a color is printing weak that a color calibration fixed the problem. What do you mean the developer unit has less developer? Do you mean toner?

[pinspin]

Re: Bizhub C308 , not enough black

have you tried color calibration from service mode? Do you have some examples of the problem? I have found very often that when a color is printing weak that a color calibration fixed the problem. What do you mean the developer unit has less developer? Do you mean toner?

- Yes , we performed calibration after replacing the developer unit . Black was perfect , but after 5000 copiers the black became weak.
- The developer poured out of the developer unit , but we have not found yet where the developer falls .

[jrf]

Re: Bizhub C308 , not enough black

- Yes , we performed calibration after replacing the developer unit . Black was perfect , but after 5000 copiers the black became weak.
- The developer poured out of the developer unit , but we have not found yet where the developer falls .

We had a similar issue with a C368.
It was a bad connection on the black toner supply unit, it's located at the front of the machine under the output tray.
Good luck

[tech51]

Re: Bizhub C308 , not enough black

You don't say if you've replaced the drum.
I had a faulty drum once which drained the cyan dev, swapped it into the magenta & it drained that one as well.
The drum was underlife & showed no sign of wear so it might be worth a try.

[Reed]

Re: Bizhub C308 , not enough black

I agree with Tech51. Try a new drum. I have seen faulty drum units on other machines (Sharp & Toshiba ) pull developer causing light copies/stripes.

[kenpio]

Re: Bizhub C308 , not enough black

Had a C658 that drained the developer just on start up! Changed both the drum and developer and all was well. Yes change the HV unit also as per KM.

KEN

[EarthKmTech]

Re: Bizhub C308 , not enough black

faulty drums are easy to test - theres no need to swap to another position and destroy yet another developing unit. Pull out your multimeter set to ohms and check for continuity between rear side contact and PCR shaft. The developer pulling fault is caused by lost connection to the pcr.

Haven't seen this as an intermittent fault yet, it either always works or it doesn't but I guess anything is possible!

[pinspin]

Re: Bizhub C308 , not enough black

We replaced the drum and cleaned contacts , copier works perfectly.Thank you very much for the help !

[G6token]

Re: Bizhub C308 , not enough black

- Yes , we performed calibration after replacing the developer unit . Black was perfect , but after 5000 copiers the black became weak.
- The developer poured out of the developer unit , but we have not found yet where the developer falls .