HP LaserJet 4
| Company type | Product line |
|---|---|
| Industry | Printing technology |
| Founded | 1992 |
| Founder | Hewlett-Packard |
| Defunct | 1990s |
| Successor | HP LaserJet 5 series |
Area served | Global |
| Products | Monochrome laser printers (LaserJet 4, 4L, 4P, 4Si, 4V, 4LC, 4LJ Pro) |
| Parent | Hewlett-Packard |
The HP LaserJet 4 series, frequently referred to as LJ4 or HP4, comprises a range of monochrome laser printers developed by Hewlett-Packard (HP) during the early to mid-1990s within the LaserJet product line. This lineup encompasses models designed for distinct user groups: the base LaserJet 4 aimed at corporate environments, the 4L suited for individual users, and the 4P intended for small business operations. Additional specialized models include the robust 4Si, crafted for demanding commercial use, and the 4V, a B-size printer tailored to meet the needs of desktop publishing and graphic design professionals. Versions equipped with PostScript capabilities bear the '4M' designation, signifying compatibility with systems such as Apple Macintosh. HP also launched enhanced iterations named the 4 Plus ('4+') and 4M Plus ('4M+').
Celebrated for their ruggedness—particularly the 4/4M/4+/4M+ variants—the LaserJet 4 series combined sturdy build quality with integrated PCL and optional PostScript functionality, technologies that remain relevant in contemporary computing environments. HP’s leadership in laser printing throughout this period was largely attributed to these printers’ dependable performance, attractive pricing, and extensive market reach spanning personal to heavy-duty business applications.
Production ceased during the 1990s, with HP endorsing the HP LaserJet 5 series as their replacement. Nevertheless, LaserJet 4 drivers continue to enjoy broad software support and are commonly employed as substitute drivers for other printers compatible with PCL.
Common issues
The EX (and EX+) print engine is well-regarded for its robustness and durability, accommodating a monthly duty cycle up to 20,000 pages. Many units have demonstrated longevity beyond one million pages printed, reinforcing their reputation as reliable workhorses. Despite this, extended operation can result in typical mechanical wear, especially since these models were succeeded by the LaserJet 5 in 1995.
Paper exit jams
A frequent malfunction involves "accordion" or "washboard" jams, where paper becomes tightly folded along the exit path, often occurring behind the rear access panel. This symptom usually points to deteriorated delivery rollers at the final stage of paper ejection. Replacement roller kits are widely available and effectively address this issue. Cost-effective maintenance alternatives include augmenting roller diameter using heat shrink tubing to enhance traction or roughening roller surfaces with coarse abrasive paper to reduce slippage—both strategies help prolong printer service life.
4/4M
Launched in 1992, the initial LaserJet 4 utilized the Canon EX laser print engine and delivered printing speeds of eight pages per minute. Its paper feeders lacked extension capabilities.
4+/4M+
Introduced in 1994, the LaserJet 4 Plus (4+) upgraded to the Canon EX+ engine, increasing print speed to twelve pages per minute. Duplex printing was available optionally through an accessory (HP part C3157A). The processor frequency rose from 20 MHz to 25 MHz thanks to Hewlett Packard's Memory Enhancement Technology, while the printing system supported improved grayscale rendering. Additionally, these models featured a power-saving standby mode consuming between 20 and 30 watts—an energy conservation feature absent from the original LaserJet 4.
4Si
The 4Si and its Macintosh counterpart, the 4Si MX, were robust business printers powered by the Canon NX engine. Capable of printing at 17 pages per minute, these models accommodated paper sizes up to 8.5"x14" and offered optional upgrades such as duplex printing and envelope feeders.
A prevalent problem with earlier IIISi and 4Si units is the occurrence of "phantom paper jams" during extended print runs. This issue stems from a delayed release of the solenoid within the paper tray assembly, causing gradually decreasing top margins and erroneous jam alerts. Resolving this requires removing the felt pads from the solenoids, thoroughly cleaning off adhesive residues, and inserting cushioning materials—though this repair demands disassembling a significant portion of the input mechanism.
4L and 4P
Within the LaserJet 4 lineup, smaller models were designed for individual users and small businesses: the 4L and 4P, along with their Macintosh-compatible versions, 4ML and 4MP. Both employed the then-new Canon PX engine. The 4L operated with a 300 DPI PX engine, while the 4P upgraded to a 600 DPI PX-II engine. Notably, the 4L introduced energy-saving features that powered down the device during periods of inactivity. It was also the first LaserJet assembled using a "Mass Customization & Bulk Shipping" approach, where key components were regionally assembled near customers. This method significantly reduced tariff expenses and shipping fees by millions and shortened delivery times by several weeks. Initially implemented in North America, Europe, and Asia, this strategy focused on entry-level models like the 4L and 4P.
4V
Targeted at graphic designers, the B-size 4V and its Macintosh version, the 4MV, utilized the Canon BX-II engine. Released in 1994, these printers captured a significant market share due to their competitive pricing. The 4V series was HP's first to offer an optional internal hard drive. Although generally dependable, they commonly experienced accordion-style paper jams caused by worn pickup rollers or damaged gears in the fuser door assembly. Typical maintenance involved replacing components such as pickup rollers, fuser doors, or delivery rollers.
4LC and 4LJ Pro
The 4LC and 4LJ Pro were adaptations of the 4L model tailored for Chinese and Japanese markets respectively. Introduced in April 1995 (4LC) and May 1995 (4LJ Pro), these printers were HP’s initial offerings specifically designed for China and Japan. Both incorporated a newly developed two-byte PCL font system for Asian characters, featured memory enhancements, and operated at a resolution of 600 DPI with standard 2MB RAM.
Macintosh variants
Models bearing an 'M' suffix across all four series were optimized for Apple Macintosh systems. These variants included enhanced networking capabilities such as JetDirect Ethernet or LocalTalk support, integrated PostScript Level 2 functionality, and increased default memory capacity.
Comparison
| Model | Release Date | Canon Print Engine | Print Resolution (DPI) | Print Speed (PPM) | Standard RAM (MB) | Maximum RAM (MB) |
|---|---|---|---|---|---|---|
| 4 (4M) | October 1992 | EX | 600 | 8 | 2 (6) | 34 (26) |
| 4Si (4Si MX) | April 1993 | NX | 600 | 17 | 2 | 34 |
| 4L (4ML) | May 1993 | PX | 300 | 4 | 1 (2) | 2 (2) |
| 4P (4MP) | October 1993 | PX-II | 600 | 4 | 2 (6) | 26 (22) |
| 4+ (4M+) | May 1994 | EX+ | 600 | 12 | 2 (6) | 66 (50) |
| 4V (4MV) | September 1994 | BX-II | 600 | 16 | 4 (12) | 68 (52) |
| 4LC/4LJ Pro | April/May 1995 | |||||
| 600 | ||||||
| 2 |