Microsoft Knowledge Base Article 895612 contains the following introduction:
This article describes how to find a compatible printer driver for your computer that is running a 64-bit version of Microsoft Windows. The information in this article may be useful if you cannot obtain a WHQL signed printer driver from the printer manufacturer or from the Microsoft Windows Update Web site. This article also provides a method that you can use if you need a printer driver for a printer that is not supported on your computer that is running a 64-bit version of Windows.
Note To print from a computer that is running a 64-bit version of Windows, you must have a 64-bit printer driver. You cannot use a 32-bit printer driver on a computer that is running a 64-bit version of Windows.
