Thanks for all the replies. I found out what was going on. The black cartridge ran out of ink but the software didn't indicate it (based on # pages printed). I think it dried out rather than the ink actually being used. I use it infrequently; I print documents on my Brother and print envelopes on my Lexmark because the Brother seems to crunch envelopes. To continue, the printer started printing envelopes in red and then nothing. The envelopes would move through the printer, the print heads would do their thing but it wouldn't print. No error message. This is when I replaced the black cartridge. No joy. I then reinstalled the software. No joy. Here's what I think happened. The color cartridge was also out of ink and again the software didn't indicate that condition (based on # pages printed). So the printer thought it was printing based on pages printed but it wasn't. The solution was to change the print characters to black. And walahhhh, it now prints my envelopes.
Thanks again for all the help.
Sail