Hello dre1123,
The shelf life of an opened imaging unit is very short! If you have not exposed it to light (any light of any kind) it should last for quite some time if it's just sitting in the dark. If it is not hidden from the light, the symptoms will be an area of under-toned print or possibly the whole page will be under-toned. The surface area of the OPC Drum that has been exposed to light will have a reduced ability to receive and transfer toner to the paper.
I hope that this answered your question.
John
