Less than 21ppm	21 to 30 ppm	Sharp Laser	Sharp	Office Equip
21 to 30 ppm	31 to 45 ppm	HP Inkjet	Okidata
31 to 45 ppm	46 to 55 ppm	HP Laserjet
46 to 55 ppm	56 to 70 ppm
56 to 70 ppm
71 + ppm