Canon Ip1800 Driver Download Windows 7

When I go to the Windows 7 compatibility center, I find that the Canon ip1800 USB ink jet printer is compatible with Windows 7 x64. When I plug my printer into a USB port on the back of my eMachines ET1831 running Windows 7 x64, in Device Manager an Unknown device under Other devices appears. Simultaneously, in the Devices and Printers window, a new category named Unspecified appears containing one item - USB Composite Device.
I have tried to manually install a driver for the USB Composite Device. The driver I tried to install was a Vista x64 driver for my printer. All seemed to be going well untill I received a message that the driver didn't have the proper digital certificate.
When I visit the Canon web site, there are no Windows 7 drivers available for my printer (x86 or x64). When I call Canon tech support they say that's correct. They don't distribute Windows 7 drivers. I must obtain them from the computer manufacturer or Microsoft. When I protested, they would simply reiterate that the procedure for Windows 7 was different, and that I must get my drivers elsewhere.
When I go to the eMachines site, as I expected the only drivers availabe are for the harware inside the computer box. When I call eMachines tech support, they say sorry, they don't supply printer drivers other than those that come prepackaged in Windows 7.
Scrutinizing the Microsoft web site, I find no place to download third party printer drivers. I do find references to 'go to the manufacturer's web site'.
I find myself in the middle of an equilateral triangle with the vertices inhabited by Microsoft, eMachines and Canon. Each has both arms raised with forefingers pointing at the other two vertices saying 'It's not my problem. Try them!'.
Since Microsoft claims that the Canon ip1800 is compatible with Windows 7 x64, a driver must exist. Please inform me how I may obtain it. The automatic procedure is not working, and there seems to be no backup.
HELP!