Strong’s Office Systems, 1040 Vt., has announced plans to close part of its Lawrence business Tuesday.

The announcement marks the third Lawrence store in the past year to exit the office supply market. Earlier this month, Sav-On Office Supplies closed its only Lawrence location at 2020 W. 23rd St. Laser Logic Inc., a Lawrence computer supply company that added an office supply division in 1999, closed its office supply operations in September, owner John Ross said.

In a recent letter to its customers, managers of Strong’s cited “superstores and national chains” as the primary reason for the decision to exit the office supply market.

“In the last five years there have been some really large national office supply groups here,” said Connie Warkins, Strong’s workplace consultant. “Many of our big accounts who used to buy all their supplies locally now are corporately ordered to purchase elsewhere.”

Office Depot, the world’s largest office products seller, opened a store in 1999 at 2525 Iowa.

Seven Lawrence employees will lose their jobs as a result of the Strong’s closing, Warkins said.

“It’s been a tough go for a number of years, and I can understand why they made the decision,” Warkins said. “I’m saddened by the fact that there are people here who are going to be losing their jobs after being here for a long time.”

Warkins said the store planned to enhance its office furniture design and supply businesses.

“Our furniture part will be here and will take the whole building,” she said. “We had a very good, strong year in furniture last year, and with the growth of the community, I only see great things in the future.”

The closing of Sav-On Office Supplies cost four employees their jobs. Laser Logic Inc., 2214 Yale Road, continues to sell and service laser printers at its location.

The recent shifts have left Lawrence with two office supply stores: M&M Office Supply, 623 Mass., the only independent supplier, and Office Depot.