I have a new Canon MG 5250 printer and am trying to set it up so that I can select which tray to print from as I use different types of A4 paper (ie I sometimes use up old paper which has printing on one side.) I just cannot find the directions to do this in the manual. Most of the time I want to print just one document from the rear tray.
You should be able to go to Devices & Printers - right click on your Printer and select Printing Preferences - under Tab for Printing Shortcuts select Paper Source - there you should have a choice of Trays
I have a slightly different Canon printer, but it operates in a similar way. To be honest, I find that it is a bit hit and miss in its selection of trays from which to print and will sometimes print from the cassette even if I select rear tray as the source.
I find the only guaranteed way is to pull out the cassette tray before printing. It should, in theory, be possible to set one tray up as the dafault and just change it to the other tray when required by selecting PRINT from the main menu (do NOT use the print icon on the toolbar). Under "Properties" you can select the paper source as a one-off after which the default applies again. But, as I say, on my printer it does not always work so I finish up pulling out the cassette tray.
My Canon printer also has a little switch that allows you to manually select either the rear or the cassette and this overrides the default. You just have to remember to toggle it back again when you have finished using the non default tray (or you will get as I often do, a section of the crossword copied from the newspaper on beautiful high definition glossy photo paper).