You forgot to mention what version of OS X you are running, but you may need an updated driver.
Printer and Scanner software available for download:
Here's a link to the MP640 printer driver for 10.5 and onwards.
You will need to remove the printer you currently have in Print & Fax and add it again after installing this new driver.
Note that when you select to add the printer, the scanner will appear quickly but the printer, shown as canonijnetwork in the Kind column, can take up to 15 seconds longer to appear.
But now it doesn't recongnise the both side printing option .... Do you know what I should do to get it. Actually it is so great to print that it is just an option !!! I also have a problem as it always print in color even if I ask for grayscale print.... it has a lots of bugs !! and this is painful as I don't know how to say that I don't care if the magenta color is empty which is happening know and it doesn't want to print anything ! I am sorry there are so many bugs but maybe I sould uninstall and install again everything. My version is 10.6.8 snow leopard.
Thank you for your help!!