TechBooks, a Fairfax company that helps publishers format and convert books and reports into digital form, has acquired Maximize Learning, an online-learning firm based in Pune, India.

Financial terms of the deal were not disclosed, but the purchase will add more than 400 employees to TechBooks' staff of 2,500.

The acquisition is TechBooks' second big announcement in as many weeks. On Aug. 17, the privately held firm said it landed a $45 million investment from American Capital Strategies Ltd. of Bethesda.

TechBooks was founded in 1988 as a publishing company but transformed its business model soon after. Today the company, which has most of its staff in New Delhi, provides outsourcing services to other publishers.

For instance, if the publisher of a medical journal wants to create an online database of past issues, it might tap TechBooks to convert each issue, code the documents with XML language, add hyperlinks and make the text searchable.

The company also prepares and formats textbooks and reports -- such as Securities and Exchange Commission filings -- for both print and online publication.

Rakesh C. Gupta, TechBooks chief executive, said the purchase of Maximize Learning broadens the company's menu of online content services. Maximize creates custom e-learning courses for companies. So if a credit card company is introducing a new product, it might hire Maximize to develop a short online course to explain the new product to employees and customers.

The investment from American Capital Strategies is TechBooks' fourth round of funding. The firm had previously raised a total of $24 million from various investors. Gupta said the new cash infusion will be used to pay off some old investors, complete the acquisition of Maximize and look for other purchases.