HP Inc. agreed to buy Samsung Electronics Co.’s printer business for $1.05 billion, a deal designed to help the Silicon Valley company expand into high-volume devices that handle printing and copying for office work groups.

The transaction, which is subject to regulatory approval, is expected to close within 12 months, the companies said Monday. After it is completed, Samsung has agreed to make an equity investment of $100 million to $300 million in HP through open-market stock purchases.

HP, created as part of the breakup of Hewlett-Packard Co. last fall, sells personal computers but gets most of its profit from supplying ink and toner for the printers it sells. It is the market leader in the desktop-class printer segment.

That business hasn’t been growing lately, in part because PC users print fewer pages these days. HP last month reported that revenue from ink and toner supplies declined 18% in the third fiscal quarter from the year-earlier period, while printer hardware unit sales were down 10%.