Personal laser printers appeared in the desktop printer market with the introduction of the LX print engine, which was featured in the Hewlett-Packard LaserJet IIp (1989) and IIIp (1991). These printers, featuring 300 dpi resolution and 4 page per minute (ppm) print speeds, stayed in production for nearly five years. The unique design of the LX engine had the paper feed in a vertical direction, which allowed the printer to have a relatively small footprint for desktop use.
The introduction of the LX engine also marked the beginning of a new, compact cartridge design. The cartridge was held together with two cartridge pins and separated into two distinct sections - the waste bin and hopper. Similar designs can be found in the FX-V and BX/BXII cartridges.
The LX cartridge was the first Canon cartridge to use a primary charge roller (PCR) to replace the corona charging and erase lamps found in earlier SX and CX cartridges. The PCR allowed a reduction in high voltage power supply size, weight and cost. Elimination of the erase lamp assembly saved cost and space around the drum, as well as reduced Ozone emissions from the printer. Most unusual about the LX was the very limited access to the wiper blade for replacement as the blade screws were enclosed in the sealed waste bin section.