I just bought a Canon Pixma MX922 and am trying to print #10 envelopes. Will not print full length?

I just bought a Canon Pixma MX922 to print invitations for my best friend's wedding. I am trying to print the #10 envelopes and it recognizes the paper. The envelope is setup in MS Word. When i print it, it will not print on the last 1-1.5 inches of the envelope. I've tried changing the margins, the paper size, the font...i've converted it to a PDF and to a JPG and no matter what I do, it won't print on the tail end of the envelope. HELP!