How Printer Ink Works

The differences between the two make each better suited for different purposes. Laser printers are faster (printing more pages per minute), tend to produce higher quality results (with some exceptions) and are more well-suited for high-volume printing than inkjet printers. Laser printers also print much sharper lines and are therefore well-suited for text, logos and simple business graphics. The economical laser printers are mostly monochrome, however. Modern inkjet printers print both black and white and color these days, and they have an edge on laser printers for photo printing because they tend to blend colors better. There are, however, expensive commercial color laser printers that are good at printing photos.

Resolutions vary from printer to printer. They've improved greatly since those early 96-dots-per-inch (dpi) inkjets in the mid-80s. The first desktop inkjet printers only had 12 nozzles on the printhead, but new printers have hundreds, sometimes even thousands, all less than half the thickness of a human hair, improving resolution greatly. Resolution has also been improved by the use of lighter cyan and magenta inks, colors that appear smaller to us, and the ability of printers to spray different drop sizes [source: Mitchell]. Common default resolutions for inkjet printers are 300 to 600 dpi, with higher resolutions possible in a lot of printers, some going into thousands of dots per inch.

The earliest desktop laser printers (including that first HP LaserJet) printed at 300 dpi resolution. Common laser printer resolutions today are 1200 or 2400 dpi, with some lower-end models printing at 300 or 600 dpi. All are perfectly adequate for printing most documents, with dpis in those ranges not being terribly discernible from one another to the naked eye. Dpi does make a noticeable difference with photo printing.

With inkjet printers, the ink usually dries quickly, but in some cases the wet ink may need a little time to dry, so you can smudge it if you handle a newly printed page. With laser printers, the ink is fused to the paper before it exits the machine and does not smudge. The type of paper also makes a difference. Ink bleeds and spreads out on paper if it's too porous. Brighter white 24-pound paper is usually recommended for inkjets, rather than lighter 20-pound paper used for copiers and laser printers. Special photo paper is advisable for printing photographs.

The ink itself can affect print quality as well. Dye-based inks (which are soluble in water or other solvents) are better for blending colors and are therefore best for photos, but they may result in lines that are less sharp. Pigment-based inks (with insoluble pigment particles suspended in liquid) tend to result in sharper lines, so they're better for text, logos and other simple graphics. Indecisive? It's possible to find printers that let you swap cartridges to the type of ink you need.