The firm, formerly known as Dittoprint, hopes the investment will take it into the PrintWeek Top 500 by adding at least 2m to its current 3.3m turnover.
It is replacing a four-year-old four-colour press but will retain a five-colour Speedmaster 74.
It is also adding a second buckle folder and Polar 92ED with Transomat powerlift and jogger.
The firm prints match programmes for both Rangers and Celtic, and chief executive Jim Watt said the new press would enable it to turn around the Rangers job in three hours.
DP21 employs more than 50 staff and also has digital printing capacity.
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