The machine, which will be operational by February, is expected to boost the company's digital colour output by 30%.
It will run alongside Indigo 5500 and 5000 presses at the 135-staff Exeter site, which serves book, journal and magazine publishers.
Andrew Lee, managing director at Polestar Wheatons, said the increased level of demand had come as more customers were looking for print in shorter runs.
"People are looking at the coppers a lot more, they don't want to pay expensive storage fees or have to pulp print that doesn't sell," he said.
"Digital print is the future and it is only a matter of time before it begins to put more pressure on litho technology."
The new Indigo also complements a mono operation that includes an Océ 9210 VarioStream press, which was installed less than a year ago.
Lee said: "We are delighted to be expanding our portfolio with the ability to produce litho-equivalent print, in up to seven colours and on a vast array of substrate weights."
Digital colour boom leads Polestar Wheatons to Indigo 3250 buy
Polestar Wheatons has responded to a growing demand for colour digital work by making its third investment in digital kit within 12 months with an HP Indigo 3250.
