David Nugent scored twice in four first-half minutes, David Jones made it three before the interval and sub Patrick Agyemang made it four five minutes from time, while Town rarely threatened Carlo Nash.
Ipswich made a decent start and Graham Alexander had to be alert to deny Ian Westlake after he was freed by a fine Owen Garvan crossfield pass.
Preston could have scored with their first real attack when Tyrone Mears' deep cross found Danny Dichio steaming in unmarked, but he thumped his header against the near post.
Nugent was booked for a bad foul on Luis Sito before Jim Magilton almost put Sam Parkin in, only for Chris Lucketti to block off the Town striker.
Lewis Price saved a looping Dichio header, Jones shot over from 20 yards twice, the second landing on the roof of the net, before Nash went full length to beat away a fierce low Magilton drive.
That proved to be a turning point as, a minute later, Jones won a loose ball close to halfway and played a perfectly weighted ball to free Nugent and the England Under-21 forward coolly slotted past Price.
On 34 minutes it was 2-0 as Paul McKenna played the ball in to Nugent, whose dazzling close control saw him beat two defenders before lashing an angled drive across Price.
Town made a change on 40 minutes when the lively Dean McDonald replaced Kevin Horlock and within a minute he collected a Westlake lay-off to fire a strong shot not far over.
Preston gave Ipswich a mountain to climb in first-half stoppage time as Jones and Dichio played a one-two on the edge of the box, with Jones collecting, holding off Matt Richards and sliding a shot beyond Price.
It made the second half a formality, and both teams seemed to know it, with no goalmouth action at all until after the hour, when McKenna's corner found Brian O'Neil unmarked, but he headed straight at Price.
Preston were playing within themselves, but they raised their game again late on to score a fourth, with sub Patrick Agyemang racing on to a hoofed clearance, holding off young defender Aidan Collins, before comfortably beating Price.