Kyocera 2160 Color Fundamentals

The Color Laser Printer Guide: Industry Briefing

Color Fundamentals

Let’s focus next on some of the main technical and per-

formance issues that crop up in any discussion of color

printers.

Laser basics

As with monochrome machines, color laser printers work

by having a light source etch an image onto a photosen-

sitive drum that then attracts toner; the toner is trans-

ferred to paper, heated, and fused; and an image is creat-

ed. The difference is that with monochrome lasers, the

process is completed with one pass through the machine,

but with older color models, the imaging (at least tradi-

tionally) takes place a total of four times — one for each

of the four process colors from which all composite col-

ors are formed. This explains why color print speeds have

typically been much slower.

But lately, the fastest models are using tandem engines

featuring a one-pass process, resulting in color speeds

that are the same or almost as fast as black-only ones.

The engine prints the three basic printer colors — cyan,

magenta, and yellow — in tandem with black, in a single

pass of the paper through the imaging unit. These one-

pass engines may be either laser- or LED-powered.In the

past few years, this technology has almost completely

taken over the industry. Only older and less expensive

models offer four-pass color.

Solid ink jet: laser-class alternative

Solid ink jet technology shouldn’t be confused with ther-

mal ink jet, the much more common and less expensive

variety. The image quality, full-color speed, and price of

solid ink jet all place it in the laser class.

At present, Xerox is the only vendor in this guide that

offers products using solid ink jet technology. (As we

mentioned above, Xerox also sells color laser and LED

printers.)

Solid ink jet technology relies on a solid block of ink

that’s melted and dropped precisely onto the paper.The

ink resolidifies immediately in a process designed to

maintain its clarity.Because very little ink soaks into the

paper, solid ink jets deliver brighter colors than regular

laser.Speeds are brisk by full-color standards.

Solid ink jets aren’t fussy about what type of plain paper

they print onto — they generally work fine with regular

copier and laser printer paper.One benefit of the technol-

ogy is that the output doesn’t smudge if it gets wet.

Recent developments byXerox have diminished some

earlier disadvantages of solid ink jet printing, such as a

tendency to jam in copier document feeders due to added

thickness and its vulnerability to scratches.

Xerox’s solid ink jet machines are comparable to the

less expensive color lasers. Therefore, the product posi-

tioning stresses brilliant colors, along with economy,as a

reason to opt for this technology.Xerox has established a

successful niche with these printers.

You may sometimes hear solid ink jets referred to as

“phase change” printers, a term that refers to the melt-

ing/resolidifying process — there’s no special signifi-

cance to this, and the term is synonymous with “solid ink

jet.”

The colors themselves

All color print technologies involve mixing three or four

basic colors to create millions of color combinations. You

may hear of a three-color palette abbreviated “CMY,”

standing for cyan, magenta, and yellow. To form a com-

posite black, CMY printers combine the three primary

colors.

However, current color laser printers — including all

featured in this guide — have a separate,tr ue black (des-

ignated as “K” in printer lingo). This four-color palette is

referred to as “CMYK,” and it’s preferable to the three-

color variety: CMYK models typically generate richer-

looking black text than those that combine the CMY col-

ors to create composite black. The colors themselves

come in the form of different substances, depending on

the print technology — in the case of lasers, it is toner.

Keep in mind that computer monitors use a different

palette — red, green, and blue (RGB) — to mix their col-

ors. Toreconcile the two color sets, some printers include

color-matching software that lets users specify which

monitor they have,enabling the printer to adjust the out-

put to matchthe monitor.

In addition, there is a whole subindustry devoted to

third-party software and hardware tools designed to con-

trol, match, and calibrate color to satisfy the pickiest peo-

ple. Advanced users (especially those in the graphic arts,

publishing, and design businesses) will look for “manual”

controls. However, most mainstream users will be con-

tent with software that automatically optimizes color

reproduction to suit the content of each page.

How important is resolution?

The best way to judge print quality is simply to look at it.

If you must judge image quality by reviewing machine

specifications, you should be aware that there are differ-

ing schools of thought as to what matters most. In the

black-and-white market, the main reference point on a

spec sheet when it comes to image quality is a printer’s

resolution. This is measured by the number of dots per

square inch, normally noted as the number of dots per

inchin a row times the number of dots in a column. For