telephone answering device -- TAD
what is your contrast /resolution set to?
maybe that is it??
is the glass smudged or filmy?
found some info about black faxes being sent-
http://www.fixya.com/support/t395454..._sending_solid
http://www.fixya.com/support/t102413..._sending_solid
this one has a bunch of solutions see # 8 for a free /easy one first.