Future reference: For "unknown distro" on HPLIP, you need only go into the files and change "ubuntu" to "zorin" and then run the installer - it will work just fine.
Sorry but I don't understand what you mean. I just checked the hplip folder in my downloads folder and I can't see 'ubuntu' anywhere in the files or folders.
It is one of the files within the installer- and is content within the file. It is not a file named Ubuntu and I uhhh... realize now I cannot remember the name of the file.
It's been a while... And I commented off hand as I thought your issue was solved.
I did a search of posts on the topic of the forum as we on here have covered this a few times... Haven't found that particular technique but I did find a post from azorin re: Zorin 15, but should still be applicable: