So, after I read all thread and tried different suggested solutions (thank you, guys!) I finally managed to make my Canon I-Sensys MF4140 to work in my Ubuntu 12.04 64-Bit version.
1. Downloaded the UFR II Printer Driver for Linux Version 2.50 from Canon U.S.A.
2. Extracted from archive and converted the 64-Bit RPM drivers to DEB:
3. Renamed existing '/usr/lib64' to '/usr/lib64.old'
sudo alien cndrvcups-ufr2-us-2.50-1.x86_64.rpm --scripts
sudo alien cndrvcups-common-2.50-1.x86_64.rpm --scripts
4. Created the symbolic link '/usr/lib64' to '/usr/lib':
sudo mv /usr/lib64 /usr/lib64.old
5. Installed dependencies (I do not know if I realy needed all of them ):
sudo ln -s /usr/lib /usr/lib64
6. Installed the .deb packages:
sudo apt-get install libc6-i386 ia32-libs lib32z1
7. Plugged the printer and it worked!
sudo dpkg -i cndrvcups-common_2.50-2_amd64.deb
sudo dpkg -i cndrvcups-ufr2-us_2.50-2_amd64.deb
(I printed a test page and a page from a PDF document).