Printer problem

Hello,

To begin with, it may be a good idea to reset the printing system. Does the operating system offer a suitable driver to use?

Reset the Mac printing system to solve a problem - Apple Support

Add a printer on Mac - Apple Support

According to Canon's support page, the PIXMA iP100 does not have supported printer drivers for anything later than macOS Mojave 10.14.

https://www.canon-europe.com/support/consumer_products/products/printers/inkjet/pixma_ip_series/ip100.html?type=drivers&language=en&os=macos%2010.14%20(mojave)

This does not necessarily mean that it is impossible to use a newer operating system, but do not expect too much.

You could possibly test the Canon Printer Drivers v3.4 for macOS package download from Apple at https://support.apple.com/kb/DL1928?viewlocale=en_US&locale=en_US as well (a Canon iP100 series version 16.10.0.0 driver is mentioned in the article Printer and scanner drivers for Mac - Apple Support). It may or may not work.

Before testing printer drivers, make sure that you have backup copies of all important files (documents, photos, et cetera). Software conflicts cannot be ruled out.