Until 1984, desktop printing was the domain of daisy-wheel and dot-matrix technology.

Desktop printers were called impact printers because they required a printing head to contact the paper to leave an impression.

By today's standards, the printers were slow. They had limited ability to change fonts on a page, and at 150 dots per inch they couldn't reproduce graphics well.

Then Hewlett-Packard introduced its LaserJet printer at Comdex, a former annual electronics industry convention in Atlanta.

"The LaserJet stole the show in Atlanta," said Von Hansen, an engineer in Boise who was part of the development team. "We knew we had something, but we never dreamed it would be this big."

It's HP's most successful product ever, Hansen said.

With the LaserJet turning 25 this year, the anniversary is being marked Tuesday by a sitewide celebration at the HP campus in Boise. The day will include visits from Vyomesh Joshi, executive vice president of the Imaging and Printing Group, who is based in San Diego; and David Murphy, the senior vice president of LaserJet and Enterprise Solutions, who is based in Palo Alto, Calif.

Laser printers were not new in 1984. They were invented by Xerox in 1969, but they were big machines with enormous price tags. Xerox, IBM, and Hewlett-Packard offered laser printers starting at about $100,000 each.

The first LaserJet printed 300 dots per inch - smoothing graphics dramatically - and allowed desktop publishers to mix fonts on a single page. Its cost was just $3,500.

Hansen, now 57, was an HP engineer and project manager in Boise. He and his team developed the printer in partnership with Canon, which designed the printer engine.

The team developed Printer Command Language, which made high-resolution printing with changeable fonts and smooth graphics possible. PCL became the industry standard and is still installed in every laser printer, regardless of the maker.

On a flight home from New Orleans in February, 1984 Hansen found himself seated in coach, across the aisle from Microsoft founder Bill Gates, then a mogul-in-the-making. The chance meeting led to years of support from Microsoft for LaserJet products, Hansen said.

"They had just come out with Word, and Gates just loved this product," Hansen said.

Now the vice president and general manager of value enterprise products and supplies division in Boise, Hansen has been with HP for 33 years.

LaserJet printers were assembled in Boise, and the controllers - the electronic brains of the machines - were manufactured in Boise until 1999, said HP communications manager Kipp Martell.

The original LaserJet was designed to last five years, but many have soldiered on.

A year ago Hansen found a LaserJet still being used on the desk of the dean of the College of Engineering at Utah State, where he studied as an undergraduate.

"They were built like little tanks," he said.

Brad Talbutt: 672-6737