HP LaserJet 4 (1992)

What the HP LaserJet 4 was

The HP LaserJet 4 was a desktop laser printer introduced by Hewlett-Packard in 1992 under the product number C2001A; Wikipedia dates the announcement to October 1992. It printed on cut-sheet paper at 600 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$2,199. A companion model, the LaserJet 4M (C2021A), shipped with PostScript and additional memory for Macintosh and mixed environments.

The first 600-dpi HP laser printer

The HP Computer Museum documents the LaserJet 4 as "HP's first 600 dot per inch laser printer," doubling the 300-dpi resolution that HP's LaserJet line had used since the original 1984 model. According to Wikipedia, HP's earlier LaserJet III (1990) had introduced Resolution Enhancement technology to smooth 300-dpi output; the LaserJet 4 instead delivered a native 600-dpi engine. Wikipedia notes the native 600-dpi engine produced sharper text and images than earlier 300-dpi LaserJets.

The Canon EX engine and microfine toner

Like earlier LaserJets, the model was built on a Canon print engine — in this case the Canon EX engine, an electrophotographic mechanism that HP paired with its own controller and firmware. Wikipedia notes the engine used microfine toner, a smaller-particle toner that helped the printer resolve the finer dots of its 600-dpi grid. The toner and the wear-prone imaging components were supplied together in a replaceable cartridge, following the all-in-one cartridge approach the LaserJet line had used from the start.

How a page was rendered

The LaserJet 4 formed each page by sweeping a modulated laser beam across a rotating photoconductor with a laser scanner unit, developing the latent image with toner and fusing it to paper. Incoming jobs were described in HP's PCL (Printer Command Language); Wikipedia records built-in PCL with PostScript available as an option, while the HP Computer Museum notes the LaserJet 4M shipped with PostScript as standard. Turning a page description into the dot pattern the laser writes is the work of a raster image processor.

Connectivity and memory

The HP Computer Museum notes that the LaserJet 4 offered both serial and parallel interfaces and could listen on both at the same time, and that it provided an MIO slot for an optional network (LAN) interface card. Wikipedia lists the base model as shipping with 2 MB of RAM, expandable to 34 MB, while the PostScript-equipped 4M shipped with 6 MB. Figures that cannot be traced to an authoritative source are omitted here rather than estimated.

TrueType fonts and screen matching

Wikipedia records that the LaserJet 4 brought TrueType font support to the LaserJet family, so that the fonts printed on the page matched the TrueType fonts shown on the computer screen. Combined with the higher 600-dpi resolution, this tightened the correspondence between what users saw in early WYSIWYG applications and what the printer produced.

Place in the LaserJet line

The LaserJet 4 anchored a broad family. HP offered the personal 4L and 4P models, the high-volume 4Si built on Canon's NX engine, and the PostScript 4M, and in 1994 refreshed the line with the LaserJet 4 Plus (C2037A) and 4M Plus (C2039A), which the HP Computer Museum records at a faster 12 pages per minute; Wikipedia identifies the improved engine as the Canon EX+. The 600-dpi base model succeeded the 300-dpi LaserJet III generation and carried forward the LaserJet naming and Canon-engine strategy that HP had established with the original 1984 LaserJet.

Reference scope

This page records only facts traceable to authoritative sources — HP's own museum records and archival histories — and omits any specification that cannot be sourced rather than estimating it. Documented figures for the base LaserJet 4 include a Canon EX engine, 600-dpi resolution, eight pages per minute, 2 MB of standard RAM (expandable to 34 MB), built-in PCL with optional PostScript, simultaneous serial and parallel interfaces with an MIO network slot, and a US$2,199 launch price. It is not a buying guide and quotes no current pricing or availability; the sources consulted are listed below.