Technically, they're not permanent files, but they must be constantly present if your printer is in use (and for wireless printers "in use" does not mean "currently printing").
You can generally get rid of these if you turn off the printer and reboot to safe mode, no networking, but as Allan has said it best. These will be re-created when the printer goes back online again so you're never going to be rid of them in any meaningful sense and they take up virtually no space.
Using the TEMP folder for this sort of file goes way back, and the folder you show would not normally be visible. I gather that you've allowed hidden files and folders to be shown, as have I. Most users would never know these are present.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
Memory is a crazy woman that hoards rags and throws away food.
~ Austin O'Malley