Mick McCarthy's visitors squandered a great chance to open the scoring in the early exchanges but Ashley Hemmings blazed wide while one-one-one with Town keeper Ben Smith.
Nicky Wroe responded for Town by forcing a save from Dorus De Vries, while at the other end Sam Winnall skipped past two challenges to set up James Cassidy, but Carl Regan blocked.
Steve Leslie forced a fine save for De Vries with a free-kick and James Collins sent an effort over the bar before almost setting up Marvin Morgan at the back post just before the break.
However, Town broke the deadlock 10 minutes after the restart when Shane Cansdell-Sherriff met Jon Taylor's corner with a header at the near post.
De Vries did well to keep out a low shot from Terry Gornell and deny Mark Wright with a follow up effort, but Town doubled their lead just minutes later.
Morgan finished off a fine passing move from Town when he fired past De Vries after being picked out by a threaded pass from Matthew Richards