I have seen this before, and my belief is that the envelope printing in Word acts "differently" in that it uses HTML or similar formatting by nature.
This means that the printing is done in "colour" even if b/w is specified.
The green tinge would suggest that your colour cartridge is low/empty on one colour perhaps, as normally all 3 colours would give black.
This means that the printing is done in "colour" even if b/w is specified.
The green tinge would suggest that your colour cartridge is low/empty on one colour perhaps, as normally all 3 colours would give black.