Change HP Officejet from offline to online

I cannot change my HP Officejet 6500 from Offline to Online. Scanner won't work since iMac update approximately 8 months ago.
My son uninstalls, then reinstalls printer when it goes Offline; but I can't do this every time I need to print.
Any suggestions or solutions?

I have an OFficejet 6500a Plus. I don't use the HP software at all. Just use the Apple drivers. I had to uninstall the HP drivers to get it working. I deleted the entire HP folder from Applications. When I need to scan, I open System Preferences>Print and Scan. I don't remember the exact set of steps to add the driver, but I think I just clicked on the "+" and it found the printer through Bonjour wirelessly.

The HP software interferes with the Apple drivers, which is why I couldn't scan until I got rid of it all.

Hope that helps some.