bizhub c250i C2551 cyan toner low density error

[occus]

Today i had a C2551 low density error on a bizhub c250i. The popup alert was showing to open and close the front cover and if done after 5 prints it alerts again.

The toner cyan was full but the status was empty. I reset the toner cyan with engine dip switch to full.
After i tryed to increase the toner level with manual ad toner serveral times but it does not help... (from 2% to max 2.5%)
The next step was to fill the hopper and toner again but low density persists.

I disasembled some covers and toner and check the developing unit. It seems there are no toner in the DV. It must be from hopper or backward.
After several tests i tryed to add toner with open shutters and no bottles (by the way, how can i cheat the sensor from the waste toner drive/box? that will be very usefull)
Everythings drives in the hopper, maked a comparison test with all colors how it works. So the hopper function looks good.

Next step:
The theory of operation tells me the toner bottle motor starts only (even you ad manual toner) wenn the toner empty is unblocked. Ok i try to see what happen in the black color and made 50 sheets solid full pattern print to decrease the black toner level. I see the toner bottle motor starts to drive on the right side, and the cyan at the same time for a view mm on the left and stops. The motor is the same for c/k.
On the cyan hopper i take out the toner empty sensor to clean and to unblock and made the same test but the toner bottle motor drive only a quarter...
Now i think its the toner bottle motor or if you look in the parts cataloge the Toner bottle drive assy... nice

Has anybody experience with this?

[tsbservice]

Those gears inside Toner Bottle Drive Assy looks like can be purchased(see P48 from parts manual). I will remove and disassemble this assy to check Cyan part drive.

Another thought after reading manual. What will happen if toner empty sensor/C actuator(AA2J404300) is broken?

[drowranger]

Seen it on yellow. one gear inside the toner drive assembly was not seated properly to drive frame. Try taking the drive assembly apart and reassemble before ordering parts.

[REGSIS]

Today i had a C2551 low density error on a bizhub c250i. The popup alert was showing to open and close the front cover and if done after 5 prints it alerts again.

The toner cyan was full but the status was empty. I reset the toner cyan with engine dip switch to full.
After i tryed to increase the toner level with manual ad toner serveral times but it does not help... (from 2% to max 2.5%)
The next step was to fill the hopper and toner again but low density persists.

I disasembled some covers and toner and check the developing unit. It seems there are no toner in the DV. It must be from hopper or backward.
After several tests i tryed to add toner with open shutters and no bottles (by the way, how can i cheat the sensor from the waste toner drive/box? that will be very usefull)
Everythings drives in the hopper, maked a comparison test with all colors how it works. So the hopper function looks good.

Next step:
The theory of operation tells me the toner bottle motor starts only (even you ad manual toner) wenn the toner empty is unblocked. Ok i try to see what happen in the black color and made 50 sheets solid full pattern print to decrease the black toner level. I see the toner bottle motor starts to drive on the right side, and the cyan at the same time for a view mm on the left and stops. The motor is the same for c/k.
On the cyan hopper i take out the toner empty sensor to clean and to unblock and made the same test but the toner bottle motor drive only a quarter...
Now i think its the toner bottle motor or if you look in the parts cataloge the Toner bottle drive assy... nice

Has anybody experience with this?

If I get it correctly, toner hopper is not filled with toner and toner bottle C is not turned a full circle!? In that case check the toner motor C and gears.

P.S. If hopper is filled with toner (bottles are turning) and nothing goes into developing unit - check the hopper. I had this problem on C360 series C364/e series and C368 series. Mainly the gears and bushings (C364e) were the cause, only once I had to replace hopper assy.

[tech51]

Check the paddle in the hopper hasn’t got stuck or fallen off. If it doesn’t move the machine assumes the hopper is full and never rotates the bottle.
Had this a few times on previous models.
Also make sure the sensors are clean on the hopper.

[occus]

Ok, i'm done...

Before I disassembled the Toner bottle drive I thought there was a clutch or something similar. But it works with normal left and right rotation and a gear jumps back and forth between cyan-drive and black-drive. Unfortunately the gear was stuck. I moved it back and forth manually and greased it a little. Then it worked again.


When I thought I was done i made a check of all colors (decreased toner level with full solid pattern) the device showed me the error 2555 (yellow) ... yes, I love that. I checked the gearbox at M / Y but there was nothing, the gears run smoth. after research it was the toner empty sensor.


The device has just 4000 black prints and 4500 color prints.

I hope this can save time for somebody.

1. you need only disassemble the upper back cover to get the toner drive motors
2. you can remove and install the hopper unit without remove the drums and dv's.(take care for the shutter)

[tsbservice]

...I hope this can save time for somebody.

1. you need only disassemble the upper back cover to get the toner drive motors
2. you can remove and install the hopper unit without remove the drums and dv's.(take care for the shutter)

And Thank you for following up!