Sa, who joined the club this summer, broke the deadlock inside the opening 10 minutes when Nick Blackman crossed the ball in from the right, leaving the striker to hit it first time from close range.
It did not take the visitors long to get back on level terms though, as Ryan Fraser created some space in the Reading penalty area to get a shot away, which Jonathan Bond parried straight into the path of Freddie Sears, leaving the striker with a simple tap-in.
The Royals were soon making their way back down the other end, and restored their lead within six minutes of opening the scoring through another Sa strike, this time with a long-range finish past Dean Gerken.
Ipswich had further chances to try to get back on level terms before the break, but Christophe Berra and Sears both missed the target, while Matej Vydra was unable to get a shot away down the other end.
Reading soon managed to extend their lead after the restart as Sa burst into the box looking for his hat-trick, but picked out Blackman instead, leaving the midfielder to rifle it in from a tight angle.
The home side continued to look the more likely in front of goal with Vydra curling the ball over the crossbar, before Gerken came off his line to stop the on-loan Watford striker from picking out Blackman moments later.
Ipswich tried to give themselves some hope inside the final 30 minutes as Brett Pitman attempted to head the ball over Bond, only to clatter his effort onto the crossbar.
The miss proved to be a costly one as Reading soon made their way back down the other end, with Blackman and Sa linking up again, this time resulting in the Portuguese striker diverting the ball past Gerken to complete his hat-trick.
Ainlsey Maitland-Niles came off the bench for Mick McCarthy's side in the closing stages, and tried to get in a position to grab a late consolation, but a poor first touch let him down as he lined up a shot from a cross in from the left.
There was more to come from Reading though as Oliver Norwood added a fifth for the hosts with just a couple of minutes remaining, letting a shot fly from over 30 yards out, leaving Gerken rooted to the spot as it sped into the back of the net.
The result moves Reading up to fifth in the table, while Ipswich slip to fourth.