Ricoh said the undisclosed purchase of Ridgian is part of its "long term vision" to expand and enhance its services. Ridgian and its 50-strong workforce will remain a separate company controlled by Ricoh.
Ricoh UK chief executive Phil Keoghan said the business was a "great strategic and cultural fit".
Jason Betterridge, chief executive of Ridgian, added: "Both companies operate across a wide range of industries providing a rich shared client base to which we can add value not just via expanded services, but also through harmonised processes."
"This is an exciting time for Ridgian. Becoming part of a large, global company will enable us to tap into a wider network, and develop new and unique client offerings."