How to obtain a driver for an unsupported printer model

Hi,

I am trying to get a HP Photosmart B109a-m printer to work on Ubuntu 20.04.
It used to work on Ubuntu 16.04 without me having to install any additional drivers, but although printing still works, the scanner functionality does not work anymore. The scanner is not detected anymore.
I tried to install hplip-3.21.6 as I was hoping that that would fix the problem, but hp-check fails with "error: Unsupported model: Photosmart_B109a-m".

Is there another driver that can be used to support this model or is there another way to fix this issue?

Thank you very much!

Wolfgang