bizhub 250 TCR issue C2557

[stw]

Hello,

I've been working around an ATDC sensor issue for nearly a year already, but would like to solve it now since the device also requires other replacement parts (thanks for helping me in this thread (https://www.copytechnet.com/forums/konica-minolta/165887-bizhub-250-gray-black-background-after-cleaning.html)).

There seems to be some issue with toner replenishing. I don't know why, but it seems to put too much toner in the developing unit such that the toner/carrier ratio gets into an invalid range leading to a C2557 error code.
Back when the issue first arose (about ~1y ago) I tried to clean the ATDC sensor, but that didn't change anything.

My workaround was to operate the device without a toner bottle installed until it really needs toner. I checked that via the service menu - Level info - ATDC value. When the ATDC sensor value was already out of range (too high, e.g. 8.5%) I also temporarily adjusted the ATDC gain (in sevice menu - Printer settings; e.g. from 160 to 190) to allow printing again - until the TCR was slowly sinking again with normal usage (without toner bottle installed). After quite some pages printed the ATDC value gets back into a normal range and I reverted the ATDC gain setting to its usual value.

I'm not sure whether it was just coincidence, but the issue started after changing toner bottles. The device has only been operated with original KM toner. The imaging unit is still original as far as I know. The number of printed pages per year is rather low at about 7.000 per year.

If you have an idea what could be wrong please let me know - Thanks a lot!

Best regards,
stw

[zayonc]

the solenoid bracket must be in contact with the gear teeth. if the bracket under the action of the spring does not press against the teeth of the gear, you need to change the solenoid. or wash the bracked from the sticky substance

[copyman]

zayonc gave you some good advice.

Also have you ever changed the developer powder (usually done along with drum) and do the ATDC setup properly?

[Woxner]

since it is over toning it is 100% the toner solenoid. it gets sticky from the old foam. Also you must replace dev and drum at the same time and reset the two counters. if not it will continue the toner issue. prev posts are correct

[femaster]

since it is over toning it is 100% the toner solenoid. it gets sticky from the old foam. Also you must replace dev and drum at the same time and reset the two counters. if not it will continue the toner issue. prev posts are correct

Woxner is correct. We've come across this tons of time. There is a foam noise dampening pad in the toner add drive unit. The foam gets really sticky causing the arm on the solenoid to get stuck in the open position and results in the machine dumping way too much toner into the development unit. In the image below, the relevant area is circled, and the foam pad is on the back side of the tab indicated by the arrow. Completely remove the foam and clean up any stickiness with alcohol or other appropriate glue removal product. I personally just leave it that way afterwards. You may hear a light occasional ticking noise afterwards, but it's easier to live with that than the headache of the over-toning. issue.

It's a bit of a PIA to get to this assembly and remove it in order to clean it up, but there really isn't any other options unfortunately. Good luck.

53331

[beothy58]

Woxner is correct. We've come across this tons of time. There is a foam noise dampening pad in the toner add drive unit. The foam gets really sticky causing the arm on the solenoid to get stuck in the open position and results in the machine dumping way too much toner into the development unit. In the image below, the relevant area is circled, and the foam pad is on the back side of the tab indicated by the arrow. Completely remove the foam and clean up any stickiness with alcohol or other appropriate glue removal product. I personally just leave it that way afterwards. You may hear a light occasional ticking noise afterwards, but it's easier to live with that than the headache of the over-toning. issue.

It's a bit of a PIA to get to this assembly and remove it in order to clean it up, but there really isn't any other options unfortunately. Good luck.

53331

Hi,
I have a similar problem. The developer unit is full with the toner powder and the error code c2557 came a lot of time. What can I do? How to reduce overtoning?
Thank for your help in advance!
András

[femaster]

Woxner is correct. We've come across this tons of time. There is a foam noise dampening pad in the toner add drive unit. The foam gets really sticky causing the arm on the solenoid to get stuck in the open position and results in the machine dumping way too much toner into the development unit. In the image below, the relevant area is circled, and the foam pad is on the back side of the tab indicated by the arrow. Completely remove the foam and clean up any stickiness with alcohol or other appropriate glue removal product. I personally just leave it that way afterwards. You may hear a light occasional ticking noise afterwards, but it's easier to live with that than the headache of the over-toning. issue.

It's a bit of a PIA to get to this assembly and remove it in order to clean it up, but there really isn't any other options unfortunately. Good luck.

53331

Hi,
I have a similar problem. The developer unit is full with the toner powder and the error code c2557 came a lot of time. What can I do? How to reduce overtoning?
Thank for your help in advance!
András

Umm, do what I said in the post of mine that you quoted... :confused:

[allan]

O the good old days. There was a metal pin the broke out of the toner supply assy. Remember changing every last one of those broken brackets. Took about 45min if you were quick enough.