Unfortunately, Canon does not support the Laser Shot LBP1120 under Windows 10. It was only supported through Windows 8. There are Unix drivers available here: https://www.canon-europe.com/support/consumer_products/products/printers/laser/laser_shot_lbp1120.html?type=drivers&language=en&os=windows%2010%20(32-bit)
. Since the Laser Shot LBP1120 was released with Windows 98/Me, Windows 2000 and Windows XP drivers, Canon supported this printer for over 10 years. If your system has sufficient memory and virtual machine support (BIOS or UEFI), you could try using a virtual machine with Windows 7 (with appropriate license) or a supported version of Unix/Linux to run the printer. Alternatively, create a dual boot machine with one of those OS versions on the computer.
I wish that I had better news for you.
(Another alternative is to write your own driver (or find a programmer who will do that). I don't write drivers myself.)