HP LaserJet 4

There are also PostScript variants of these machines with the '4M' designation, where M stands for, but is not limited to, usage with an Apple Macintosh.

Hewlett-Packard dominated the laser printing sector during this time in part due to their reliability, relatively affordable pricing, and the spread of LaserJet 4 models from personal use up to heavy business use.

The EX (and EX+) print engine is known for its reliability and longevity, and in comparison to earlier generations of laser printers, these machines have acquired a 'workhorse' reputation.

The heat shrink extra diameter pulls the paper quicker and resolves the wear/slip issues.

Another alternative is to use coarse quality abrasive paper such as those used by belt sanders to roughen the surfaces of the rollers.

[5] These models also feature a 20-30W power saving (stand-by) mode, which was not included in the original Laserjet 4.

The 4Si (and 4Si MX for the Macintosh) were heavy-duty business printers, produced using the Canon NX engine.

[6] The 4Si worked at 17 PPM, could print on paper up to 8.5"x14", and could be upgraded with a duplexing unit and an envelope feeder.

The error accumulates with each page printed, and eventually the paper is entering the mechanism so late that the printer believes that a jam has occurred.

This problem is fixed by removing the felt pads, cleaning off the adhesive (isopropyl alcohol works well), and placing some electrical tape or other material to provide a cushion for the solenoid.

[5] Common Fixes of the LaserJet 4V and 4MV model can have accordion jam as well, caused either by a worn roller or broken tooth on the gear at the fuser door.