Printer Lights

This printer doesn't really need a lot of controls, as document
handling is controlled in software, but it still exhibits good design.
The printer presents its status with an elegant set of 4 lights. The
large blue light is simply a power indicator, represented with the
standard power icon (though it's not visible in the picture). It also
flashes when the printer is first turned on.

The other three lights present problems and other notices to the user.
Low toner causes just the toner light to illuminate, while an empty or
broken toner cartridge lights both the Toner and Error indicators.
Similarly, an aging drum illuminates the Drum light, and more serious
problems cause the Error light to turn on as well. Finally, general
errors, such as the access door being opened, result in just the Error
light. In this way, five error states are shown with only three
lights. The simple labels help with easy recognition of the type and
severity of the problem.

-- Kevin Gessner