How can I scan from my dell v313 to my macbook air?

I have a Dell v313 wireless printer/scanner/copier. I never had an issue printing from my Macbook Air to the Dell but I have been unable to scan to my laptop. I've tried the Dell website and Lexmark software updates but nothing seems to work. A 'genius' at the Apple store told me to use my USB cable but while the laptop then sees the printer, it still won't scan.

What am I doing wrong?? I want to buy an imac to replace my Windows PC but then I won't be able to use the scanner at all.