The Leicester-based company, which is the sister business of Leeds finisher Alpha Media Solutions, said that the Cylinder was chosen because of its versatility.
As well as enabling Senator to increase production, the machine can be used to die-cut, crease, emboss and perforate.
Ian Whitfield, managing director of Senator and Alpha, said: "Senator has been trading for more than 40 years now – a real achievement for a print finishing company.
"Investments such as the Heidelberg Cylinder not only mean the company is enhancing its proposition as an innovative print finisher with added complementary services for customers, but also reducing outsourcing costs and increasing production capability."
Senator, which employs 35 staff, has a turnover of more than £1.5m, with the two businesses sharing a combined turnover of £7m.
UPDATE: This article has been amended to reflect the fact that Senator employs 35 staff, not the 125 originally stated, which is the figure for the entire group.