Blanton (2-3) yielded two runs on eight hits but didn't issue a walk while breaking a personal two-game losing streak.
Chad Qualls worked out of an eighth-inning jam and Jonathan Papelbon picked up his seventh save with a 1-2-3 ninth for the Phillies, who won for the third time in four games.
Ruiz drove in two with a single during the Phillies' four-run fourth inning and added a solo homer.
Jimmy Rollins contributed two RBI for the winners.
Cubs starter Randy Wells (0-1) surrendered four runs on three hits in a 3 2/3-inning effort.
Starlin Castro and Bryan LaHair drove in runs for Chicago.