Samsung S8 Phone

[minesapint]

My Samsung S8 android phone usually connects to my D-link router wirelessly with no problem at all. I also have my Samsung laser printer listed in the available devices section of my wireless connections on the phone. Sometimes, I'll notice that the usual notification sound for Facebook, texts etc have not been heard for hours or overnight. When I pick up the phone, it shows that no Internet is available. On checking the wireless connections, the phone shows it has connected to the printer rather than the router. Putting it right is not the problem, but I'd like to know if I can set my router to be the "default" connection that the phone should use to try to stop it connecting to my printer.
Thank you.