Complete, which employs 80 staff, supplies a range of office and production print equipment from Ricoh, Kyocera, Sharp and Samsung, as well as online print management software.
The company, whose clients include Money Advice Trust, Kings College Cambridge and South & City College Birmingham, also offers a managed print service for fleets of office printers.
Complete managing director Steve Ward, who retains his current role, said: "We have been a strong and solid business for the past 30 years and this move to Capita is a chance for the business to develop further and grow in the future.
"Capita is in a position to give the business all the support and investment it needs, building on what is clearly a success story with its existing managed print business."
David Lockie, divisional managing director of Capita Document & Information Services, added: "The business is expanding rapidly and we are going from strength to strength as our portfolio increases under direction from Alpesh Unalkat, managing director of managed print services. We are successfully pushing ahead with our strategy to grow apace and to seamlessly integrate all our businesses.
"Complete is a well-respected company with over 30 years’ experience in the print and document management business. Capita will build on that excellent reputation while continuing to deliver cost-effective and first-class end-to-end managed print services."
In July, Capita announced a £17m investment in a new 'white paper' print and distribution facility in Mansfield, including the first two Impika inkjet web presses in the UK. The company has also recently opened a new warehouse and distribution facility in Canning Town, four times the size of its previous building, and a 16,450sqm inbound mailing site, featuring digital mailrooms, storage and scanning.