I had a worrying call about a Bizhub 362 that was getting C-2557 errors. A C-2557 error on a Konica Minolta copier is caused by the Toner Concentration Ratio (TCR) sensor in the black developer developer unit reading too high. The TCR sensor reads how much toner is in the developing unit and allows the machine to control the toner level by adding toner. But if the level is too high the copier can't easily remove the toner from the developer mix and so an error is generated. Sometimes the high reading is actually caused by too much toner in the developing unit but usually by old developer mix or a faulty sensor causing a bad reading.
However the machine I am looking at doesn't have any of those things wrong with it. How do I know? Because I changed the developing unit only a month ago. Also the error only occurs during longish print runs (50 pages) and if the machine is allowed to sit for a few minutes and turned off and on again it will work fine until another long print run is started.
I went into the service menu and had a look at the TCR sensor values and they seemed normal and then did an F8 just to be sure. No good.
While waiting for the F8 to finish I went and had a look at the Konica tech bulletins for this model and found an interesting bulletin all about this very problem. The Konica boffins mention that if the ozone filter is blocked it can cause the error. So I pulled the back off the machine and pulled the filter out and sure enough it was full of dust. I vacuumed it out and the other filters while I was in there and put the machine back together. I gave it a test and no more errors!
It seems that the restricted air flow through the filter was causing the imaging unit to overheat during longer prints and then the TCR sensor would start giving higher readings until it failed.
So just because the filters are hard to get to doesn't mean that you should ignore them. Clean your filters!
No comments:
Post a Comment