One of the important aspects to think of when choosing a printer or buying a replacement cartridge, is how much ink or toner that cartridge actually contains. Amount of ink or toner in cartridge is usually called cartridge yield or page yield.
When you turn to see what the yield of a cartridge is, you will see a number of pages the cartridge is enough to print. For instance, IBM 28P2008 toner cartridge has a declared yield of 30,000 pages, while HP C6657AN ink cartridge capable of printing 400 pages. For a reason that is beyond me, ink cartridges are less capacious.
But printed pages differ from one another. One time you print a to-do list, next time it’s 10-page report.
For the purpose of cartridge yield measure, almost all printer manufacturers base their black ink/toner cartridge yields on 5% coverage. This means only 5% of the whole page is covered with ink or toner. 5% coverage implies basic type with no bold characters, no graphics and no pictures.
CMYK toners for color laser printers and copiers base their cartridges yields on 20% to 35% coverage (5% to 7% per color). In reality, if a document had a 100% fill, there would be 400% coverage. Tri-color inkjet/toner cartridges base their page yield on 15% coverage (5% per color).
Now take the last two paragraphs above and place them on a Letter-sized sheet of paper. Congratulations! You have created a sample 5% coverage page:
Let me ask you how often, if ever, you print pages like that? Who would ever need 400 or even 30,000 such pages?
Filling up the page, I managed to repeat the two paragraphs as many as 6 times, which gives us 30% coverage. This seems more like a commonly printed page:
I wonder why they don’t measure ink/toner cartridge yield in 30% coverage pages as more realistic. It’s clear that given a definite amount of ink in a cartridge, this would mean fewer pages to be printed and demonstrated.
On the other hand, I would know how many printed pages I’d have with maximum use of ink, i.e. I would be aware of the worst possible state of thing. Hence, if I print not that much text and graphics per page, I get more printed pages.
Wouldn’t it be more fair and realistic information for us, customers? I believe it would.
Whatever is the reason for using 5% coverage as industry standard, now you know what it is like and can approximate it for real-life prints.