Xerox Phaser 5500 series Дополнительное руководство - Страница 7

Questions and Answers

Stated Yield vs. Actual Yield

Color coverage varies by product class, but is generally much higher than black-

and-white products. Letter/A4-size color printers and MFPs can have average page

coverages in the 7 to 15% range (depending on application and mix between color

and black-and-white documents). Tabloid/A3-size color printers and MFPs tend to

drive higher color page coverages in the range of 10 to 30% in office environments.

In graphic arts environments, average color page coverages can increase to the 40

to 60% range. The ISO/IEC color standard is based on an overall page coverage in

the range of 20% — users whose average color coverage is under 20% are likely

to experience greater yields than reported, while those running higher coverage

applications will experience lower yields than reported.

Note — Most Xerox Phaser Printer users can check page coverage by application, or

average page coverage (for all printed jobs) by using Xerox CentreWare Internet Services

to log into the printer, or by using the Usage Profile utility from the printer control panel.

Q: If a page coverage percentage assumption is not part of the ISO/IEC standard,

how can it be useful in helping customers estimate how much yield they will get

for their applications?

A: The color and black-and-white ISO/IEC Yield Standards make use of predefined,

standardized pages that are representative of typical office documents. The black-

and-white test page has approximately 5% coverage, while the color testing suite

averages approximately 20% coverage. Differences in print engine technology and

imaging firmware mean the same document will not register the same coverage

across different engines. Customers who determine the average coverage of their

combined applications can estimate whether they will get more or less than the

published ISO/IEC yields. Customers who experience toner yields below published

ISO/IEC yields are likely printing documents with higher page coverage than ISO/IEC

testing specifies.

Q: How is color page coverage calculated?

A: Color page coverage is the sum of the individual coverages for cyan, yellow, magenta

and black toners or solid ink. Color applications tend to be more elaborate (often

including charts and images), so the area coverage tends to be much higher than

monochrome pages on average. It is not unusual to find color pages (like pictures)

with total coverage in the range of 40% to 60%, or even in excess of 100% if

"process black" is used (where cyan, yellow and magenta are combined to create

black). The color test suite for ISO/IEC CD 19798 and ISO/IEC 24711 is composed of

five representative samples of office color printing (see Appendix).

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7 – 15% Coverage

10 – 30% Coverage

30 – 40% Coverage

40 – 60% Coverage