Since our supplier sent us the wrong "encoder" wheel for our machine, we had to clean up the old one and hope for the best.  That's a combo of ink powder and pulverized rubber from a motor belt near it in the machine.

Since our supplier sent us the wrong “encoder” wheel for our machine, we had to clean up the old one and hope for the best. That’s a combo of ink powder and pulverized rubber from a motor belt near it in the machine.