MF424 will not print cleanly on No. 10 envelopes

[pditmars]

PS. Apologies for posting this in the wrong forum, but I am desperate for any possible hints as to what is going on.

I just purchased a new Canon MF424 one week ago from Amazon.Com. I am using the original toner that came with the machine. All printing is excellent except that I cannot get No. 10 envelopes to print cleanly. I am using the manual feeder.

The text has gaps in the printing and the bits that are missing appear offset by about 2 3/16" to the left. See picture below.

This does not happen if I feed a normal piece of paper (cut to envelope size) in the manual feeder. 

I am printing from MS-word 2007, Windows 7. I have set the print settings to single sided, with "Envelope No. 10" on page size and output size. I am using plain 24# number 10 envelopes. I have also tried to print on high quality envelopes with the same results.

I have tried most of the "Special Processing" image quality settings on the printer and nothing changes.  It appears that the printer cannot handle printing on something as thick as an envelope. 

Please help me fix this problem. The printer is excellent otherwise, but I MUST be able to print envelopes cleanly.

[pditmars]

Problem Solved! 

Apparently the printer MUST be told via the attached control panel that the multi-function tray is getting envelopes. I had thought that the information was passed from the computer via the driver, since there is a choice for that when you click on printer properties when you are printing.

So... if you see this problem, go to your printer and select "paper settings" from the home screen and choose "no. 10 (COM10)" paper for the multi-function tray (first tray on my screen).

Hope this helps someone.