Envelopes

[grabagrannie]

I just tried (for the first time) to print an envelope. I have a CanonMP160 printer. On the 'Printer' dialog box I selected what was already there - the icon (first icon on the left) appeared to show that, if I inserted the envelope so that the edge with the flap went in first, the address would be printed horizontally across the envelope, 6.00 cm from the left and 5.50 cm from the top. The 'Print from top' button was 'on'. This seemed to be confirmed by the print preview. The envelope is 22 cm x 11 cm.
However, when I put the envelope in and clicked 'Print', the envelope came out with the address printed vertically (!) 6.00 cm from the top (the edge that went into the printer first) and 5.50 cm from the left.
Doubtless there is some logic to this, but can somebody please explain what I did wrong, and how do I get it right