HP LaserJet (Original, 1984)

What the HP LaserJet was

The HP LaserJet was a desktop laser printer introduced by Hewlett-Packard in 1984 under the model number 2686A. It was the first product in what became HP's long-running LaserJet family. The unit printed on cut-sheet paper at 300 dots per inch and eight pages per minute, using a print engine supplied by Canon. The HP Computer Museum records a launch price of US$3,495.

A new category: the first desktop laser printer

Hewlett-Packard's own virtual museum and independent histories both describe the LaserJet as the world's first desktop laser printer — a machine small and affordable enough to sit beside a personal computer rather than in a data-center print room. HP's account compares its market impact to that of the HP-35 handheld calculator about twelve years earlier, crediting it with opening an entirely new printer market. The HP Memory Project notes that HP was among the first to bring a Canon CX-engine product to the PC dealer channel in the United States and Europe, and reports that the LaserJet went on to sell roughly 250,000 units.

The Canon CX print engine and all-in-one cartridge

The LaserJet was built on Canon's CX print engine, an electrophotographic mechanism that HP integrated into its own controller and enclosure. The HP Memory Project notes that the engine used a solid-state laser diode of the type mass-produced for compact-disc players, which helped keep the optics inexpensive. Its defining innovation was an all-in-one cartridge that combined the toner with the photoconductor drum and the charging and cleaning systems in a single replaceable unit, so the wear-prone parts were renewed with every cartridge. This is the same class of engine and cartridge architecture described in the general account of laser printing.

How a page was rendered

Like other laser printers, the LaserJet formed an image by sweeping a modulated laser beam across a rotating photoconductor with a laser scanner unit, developing the resulting latent image with toner and fusing it to paper. Incoming print jobs were described in PCL (Printer Command Language); the HP Computer Museum and the HP Memory Project both record the original model as using PCL 3. Turning that page description into the dot pattern the laser writes is the job of a raster image processor.

Documented specifications

Authoritative records agree on the core specifications. The printer produced 300 dpi output at eight pages per minute and shipped with 128 KB of RAM, which the HP Computer Museum notes was not user-upgradable. Connectivity was limited to a single serial RS-232-C interface; the HP Computer Museum states that neither HP-IB nor a Centronics parallel port was offered on this model. Figures that cannot be traced to an authoritative source are omitted here rather than estimated.

Place in the LaserJet line

The original LaserJet was succeeded in September 1985 by the LaserJet Plus, which — as documented by Wikipedia and the HP Memory Project — added expandable memory and a parallel (Centronics) interface alongside broader font support, addressing limitations of the first model. The 1984 machine nonetheless established the naming, cut-sheet form factor and Canon-engine strategy that HP carried through later LaserJet generations.