IBM, the world's largest computer company, will end an era by closing its Washington computer punch card facility--its last such plant--by year's end.

The computer punch card, with its warning against bending, folding or mutilating, has been used for purposes ranging from U.S. Treasury checks to telephone bills.

"We've been closing our card-manufacturing plants since the early 1970s," said Irwin Schorr, a local International Business Machines Corp. spokesman. "It's a business that has really been declining in the last few years."

During IBM's early years, and during the incipient stages of the computer's development, punch card data processing was at the core of the company's operations. But with the advent of newer, more sophisticated data processing techniques, IBM began to deemphasize punch card computing, Schorr said.

Some 250 employes will be affected by IBM's decision to close its Washington punch card-producing facility. They will be retrained, Schorr said, and absorbed by the company's other Washington-area offices.

As a result of IBM's decision to get out of the punch card business, the company's biggest punch card purchaser, the Treasury Department, is preparing to alter the way it processes the 550 million-plus checks it mails out yearly. Other federal agencies that issue checks--the Defense Department and Postal Service, among others--will follow suit.

By next summer, checks printed by the Treasury no longer will be printed on the familiar green punch cards, but on computer-readable paper, said William E. Douglas, commissioner of the Treasury's Bureau of Government Financial Operations.

"The federal government is the last of the really big users in the card check market," Douglas said. "We knew we had to prepare to move to paper checks. It's a current technology and we'll probably save $6 million a year."

With the passing of the punch card era, the 35 IBM 1404 punch card check-writing machines that Treasury uses will be replaced by hardware produced by Honeywell and a Minneapolis firm, Data Card Corp., Douglas said.

"The new paper check is a much more secure check, with 15 security features built in," Douglas said. "It's a multihued check and it has designs in the background to prevent counterfeiting." Production of such a check was impossible with punch cards, he added.

Punch cards have been used for electronic tabulation since the late-1800s, when a U.S. Census Bureau worker, Herman Hollerith, developed a mechanized tabulation system. Hollerith's system, which used holes in punch cards to denote census-related data, featured an electronic sorter that "felt" the holes in the punch cards and distributed them to appropriate bins.

Hoping to cash in on his invention, Hollerith left the Census Bureau in 1896 to start up the Tabulating Machine Co., which he later sold to a collective that renamed it Computing-Tabulating-Recording Corp. That company was forerunner to IBM.

Refined versions of Hollerith's original punchcard computer formed the core of IBM's business until the 1960s. After making a conscious decision to get out of punch card data processing in the late 1960s, the company began to close its card-production plants. The Washington plant was the last of nine that IBM owned.

There are very few users of punch card-compatible computers these days, said Charlotte LeGates, communications director for the Computer and Business Manufacturers Association. "It's the same technology that was used in 1940," she explained. "The only places using them now are those places that can't afford new computer systems.

"The equipment is huge and cumbersome," she continued. "It's real slow, noisy and dirty. It even needs oiling."

Eventually all users of card punch computers will have to lay the machines to rest, LeGates said. "The people who can repair them are all retired."