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pinspin
02-02-2018, 02:09 PM
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
02-02-2018, 02:21 PM
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
02-02-2018, 04:53 PM
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
02-02-2018, 05:35 PM
- 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
02-02-2018, 06:14 PM
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
02-04-2018, 06:17 PM
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
02-05-2018, 01:33 PM
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
02-05-2018, 10:45 PM
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
02-19-2018, 05:31 PM
We replaced the drum and cleaned contacts , copier works perfectly.Thank you very much for the help !

G6token
02-25-2018, 06:57 AM
- 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 .
Are you using oem toner? The toner has a certain amount of dv in it to keep the dv unit dv level “topped up”. Maybe just a faulty dv unit. Tried cleaning the Print head also?

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