I had installed MG6800 series XPS Printer Driver. Then IJ Scan Utility was not installed. After reading the following article, I installed MG6800 series MP Printer Driver without removing the XPS driver, Then IJ Scan Utility was added and started to work.
However the Scan row of Quick Menu is still empty. We have MG7720, and the Scan row has correct entries. Unfortunately, I forgot how I made Quick Menu work. I will appreciate any advice.