[Misc] Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

[Takhnamishvili]

Hello guys,

Some days ago I had a service call on bizhub Pro 951, as customer described printouts became very light, so when trying to print 100% coverage, printouts came out more likely 10% of coverage instead of 100%. After investigation I discovered that intermediate toner hopper was empty, so there was no toner inside at all, toner bottle was not empty. I removed Dev. Unit, opened it and discovered that there was very low amount of developer inside. As it seems during printing, supplying of toner stopped and machine used up developer. The strange thing is that machine does not give any error codes about abnormal density, as it seems machine does not recognize any abnormality. IDC sensor was replaced without any success. I tried to perform toner density initial adj. from the service mode and it completed without any errors too. There are 3 sensors inside machine which controls amount of toner inside hoppers,I tried to check them with I/O check mode, but got nothing, just "----" these symbols on "Out". So questions are, does anyone had issue such like this? Have anyone some ideas what might be wrong with machine? I think it may be a TCR sensor, which must recognize low amount of toner inside dev unit, and "ask" for it, am I right?

Thanks in advance..

[Albonline]

Re: Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

Hello guys,

Some days ago I had a service call on bizhub Pro 951, as customer described printouts became very light, so when trying to print 100% coverage, printouts were more likely 10% of coverage instead of 100%. After investigation I discovered that intermediate toner hopper was empty, so there was no toner inside at all, toner bottle was not empty. I removed Dev. Unit, opened it and discovered that there was a very low amount of developer inside. As it seems during printing, supplying of toner stopped and machine used up developer. The strange thing is that machine does not give any error codes about abnormal density, as it seems machine does not recognizes any abnormality. IDC sensor was replaced without any success. I tried to perform toner density initial adj. from the service mode and it completed without any errors too. There are 3 sensors inside machine which controls amount of toner inside hoppers,I tried to check them with I/O check mode, but got nothing, just "----" these symbols on "Out". So questions is, does anyone had issue such like this? Have anyone some ideas what might be wrong with machine? I think it may be a TCR sensor, which must recognize low amount of toner inside dev unit, and "ask" for it, am I right?

Thanks in advance..

print the dip switch list from a working unit and compare to your non working unit. think you will find your fix there. if you cant get a good switch list set them to factory defaults , listed in service manual.

[Takhnamishvili]

Re: Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

print the dip switch list from a working unit and compare to your non working unit. think you will find your fix there. if you cant get a good switch list set them to factory defaults , listed in service manual.

Ok, I think it will be better to set them to factory defaults.
I will update how it goes.

Thanks for suggestion

[blackcat4866]

Re: Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

The first thing I'd do is determine why the sub hopper is empty. Once you get the sub-hopper to fill, then you can address the toner density issue.

I realize there's a risk that you'll wreck new developer, but you won't know anything for sure until you install and stir new developer. =^..^=

[Takhnamishvili]

Re: Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

The first thing I'd do is determine why the sub hopper is empty. Once you get the sub-hopper to fill, then you can address the toner density issue.

I realize there's a risk that you'll wreck new developer, but you won't know anything for sure until you install and stir new developer. =^..^=

Thank you for your reply,
I filled sub hopper with toner manually, turn on MFP, tried to perform adjustments, tried to print but toner did not "go" to dev. unit anyway. So because of it, I think that problem may be in TCR sensor..

[allan]

Re: Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

Does the toner pumps kick on at that time did you check the tubes? Warning on leaving those pipes disconnected.
Check the pumps and the air separator.
Check if the toner is leaving the main hopper.
When you do these input checks close the doors.
It could be showing nothing because from startup there was no data collected and nothing to display??
Meter on the machine?

[davel]

[allan]

Re: Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

Wow great stuff in the manual about the supply operation. Rock solid design!!
If the air in the closed loop pump system gets blocked off the encoder on the pump motors they will pick up on it and error out. Less than 85% of deemed speed.
So don't think your problem is with the pumps.

You can put your ear up to the toner sensors and you should hear a whistling sound come from them if they are active.

[Takhnamishvili]

Re: Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

Hi all,

Thanks for your suggestions. Some days ago I solved problem, there was toner clogged in the tube, I cleaned the tube and problem solved.

[allan]

Re: Bizhub Pro 951 - machine does not recognize low toner amount in Dev. Unit

Are you using original toner?