High Quality Content by WIKIPEDIA articles! The HP LaserJet 4 (abbreviated sometimes to LJ4 or HP4) is a group of monochrome laser printers produced in the early to mid-1990s as part of the LaserJet series by Hewlett Packard (HP). The 4 series has various models, including the standard LaserJet 4 for business use, the 4L for personal use and the 4P for small businesses. Additional models included the 4Si model, created as a heavy-duty business printer, and the 4V model, a B-size printer for desktop publishing and graphic artists. There are also Apple Macintosh specific variants of these machines with the `4M` designation. Hewlett Packard also released an upgraded version of the LaserJet 4/4M known as the 4 Plus (`4+`)/4M Plus (`4M+`).