
My customer called me with a C2840 code. "The IDC sensor (IDCS)
output value is detected not within the specified range on the IDC sensor
(IDCS) base correction when the rough adjustment ends."
He had several 12X18 samples on 100lb gloss text paper. The background was edge to edge and images could be seen
through the magenta.
I looked inside and saw the registration senor assembly
covered with toner. Some toner could be seen inside the lens of the front registration sensor.
I pulled out the unit and cleaned it off, lens and all. Wipe down the laser windows. Vacuum up the toner.
Cleaned the paper path, as toner was falling into the path. Put the vacuum on the waste toner ports.
Changed the box filter on the right side. I also vacuumed out the high voltage contacts on the back wall
of the process cavity.
I thought this odd. For 2 years I have been servicing these two C7000's and have never had this problem.
I had just done a PM on these two machines less than 40K pages ago. I did install a transfer rebuild kit in this
machine also.
This machine also gave me a C2452. "When the developing motor /M (M21) is ON, the maximum detection value
of TCR sensor /M (TCRS/ M) is the specified value and the difference between the maximum detection value and the
minimum detection value is over the specified value."
I looked at the magenta drum and it was covered with magenta toner, very heavy.
So the next time I tried to print it gave me C2451, "When the developing motor /Y (M20) is ON, the maximum detection value
of TCR sensor /Y (TCRS/ Y) is the specified value and the difference between the maximum detection value and the
minimum detection value is over the specified value."
Ran test prints and they all had a heavy yellow background. Ran I/O programs to add toner to the yellow. The toner senor voltage
was 4.6vdc. I can bring it down. But it still prints the yellow background which depletes the toner in the mix.
So it started out with heavy magenta background and ends with heavy yellow background. What the hell happen?
Tried using a used drum in the yellow spot just to see if I could see a change in the symptom. Nope that didn't happen.
So do I have 1 or 2 issues? Excessive toner dusting and heavy yellow background or did one cause the other? And why
did it change from magenta to yellow?
Are these machines prone to collect to much toner in the waste tubes backing up the system? If this was an old Kodak
I would say the developer bias voltage shorted out. But it's not. I tried to run test prints with the yellow density at 0 and it
gave the heavy background.
Naturally it's crunch time for the customer with lots of big full color jobs to run.
Thanks for listening and any help
DR
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