It’s almost an addiction.

Take a step into Bob Schwenk’s office and it’s clear: The Government Printing Office’s managing director of plant operations is a compulsive collector. Antique engraving tools, a composer stick for setting type and a heavy printing plate are some of the relics of the GPO’s past that clutter his furniture. He has gathered it all over decades of prowling the agency’s 1.5 million-square-foot building on North Capitol Street, picking up pieces of the past before they disappear.

“He’s always been that way,” said Richard Leeds, who has known Schwenk since 1977 and works in the GPO’s Information Technology & Systems division. “He’s always been a collector of artifacts.”

Schwenk has worked at the agency for 45 years, climbing his way up from photo engraver. Colleagues say he has helped guide the GPO through the many printing transitions, recognizing the need to keep pace with rapidly changing technology. The changes have had drastic effects on the agency, not least on the work force itself: During Schwenk’s tenure, the number of employees dropped from about 8,000 to 2,200.

But Schwenk, 65, was able to find himself a place at every technological turn, and he will retire on Jan. 3 after spending almost a half-century watching printing change.

“I’m just a smart ass is all,” Schwenk joked in an interview last week. “If you don’t keep up, you don’t survive, so every time there’s a change, you adapt to it.”

Schwenk grew up across the river in Anacostia, then a working-class neighborhood. The sights of Washington were his “playground,” he said. He hung out on the Capitol steps, ran to the top of the Washington Monument on dares and spent weekday afternoons on the National Mall. His dad worked as a machinist at the Navy Yard and his mother’s family once made meals for GPO employees.

Schwenk started out at the GPO in 1962 after working a couple of years in other nearby printing plants. He was 19, directionless and needed a job. His father encouraged him to apply for an apprenticeship at the GPO — something Schwenk was not excited about at first. When he finally took the test, he didn’t make the first cut, only starting his apprenticeship after someone else dropped out.

Throughout the years, he has thought about leaving. But “there was nowhere to go,” he said, and he eventually was able to find his niche in the evolving technologies of the printing press. He made friends, developed skills and, in 1977, moved from the photo engraving division to electronic printing, taking a pay cut because he knew it was the future.

His instinct was right. He now manages 1,200 people in an environment much more integrated than when he started. With the spread of computers and digitalization, the printing process now includes fewer steps with more across-the-board input. It’s an environment in which Schwenk seems to thrive.

“There’s a camaraderie born by necessity,” said Lyle Green, director of the GPO’s Congressional Publishing Services. Green has known Schwenk since he started as a proofreader 16 years ago. “We all have to work together. We rely on each other.”

When asked about his favorite aspect of the agency, Schwenk returns to this theme.

“This is so corny: the people. It’s the truth,” he said. “Not everyone loves me but everyone knows me.”

It is hard to imagine an unlikable Schwenk. He’s friendly, talkative, laid-back. He wears his gray hair in a ponytail and jokes that a button-down shirt and khakis is the most formal he gets. It seems as though he still can’t believe how far he’s come.

“I’ve been very fortunate to get as far as I have being as stupid as I am,” he said. He’s not so much an expert in the minutiae of the printing process, he said, but in making friends and keeping business going.

But he’s certainly interested in all the details. He tells the stories behind all his objects with palatable excitement, pulling out century-old books, rusted tools, even a GPO shot glass he gleaned from a garage sale. A few years ago, he found an engraving plate that printed the first photos of the moon. It’s probably his work.

He has seen national events through the lens of the GPO. When the riots hit D.C. in 1968, he watched from a window inside the red brick building, waiting as the fires burned the neighborhoods he grew up in. He kept coming to work as many city residents fled to the suburbs in the subsequent years, and now he watches the cranes from his office window as they rebuild those once-abandoned streets. In fact, he has watched every building around the GPO go up.

And then there’s the printing. He has helped print reports on many of the important national events in the past half-century, including the Watergate and Iran-Contra scandals. Some have interesting stories: In one, he describes holding up Monica Lewinsky’s “culottes” while others took photos for a printing of the evidence in the Paula Jones trial.

But as of Jan. 3, those days will be behind him. He plans to turn to his other hobbies and collections — taking trips on the Chesapeake in his 37-foot sailboat, for example, or riding his 1957 TR 3 Roadster. He also plans to visit more antique shops for his toy car collection, which includes 1,200 pieces lining the walls of a home workshop (“I just open a beer and watch them,” he jokes).

“I’m getting bored,” he said of his hobbies, perhaps with a little sarcasm. “I think I’m going to take up golf.”