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AssigneeFujitsu Limited
InventorsMamoru Horiuchi, Yoshinori Wada, Hirotoshi Shimizu, Yuji Uehara, Masahiro Wanou, Masatoshi Kimura
Estimating the term…
A checking method for a device having a plurality of light emitting elements, especially an LED array installed in electronic printing equipment. The check is done while the LED array is mounted in the equipment and does not require removal thereof. The check is done in a short time period, so it can be done during a period of page change of the printer, without disturbing the operation of the printer. Each of the LEDs are lighted one by one with a pulse. The output emission of the array is detected by a photoelectric detector which is positioned to detect the emission from any of the LEDs. The output of the detector becomes a burst of pulses, each of the pulses representing the emission property of a corresponding LED. Each pulse is converted into a digital signal and stored in a RAM as emission data. The emission data is fed back to the driver of each LED to compensate for differences in the emission characteristics of the LEDs. This improves the uniformity of the output image the electronic printer. Each time of the check is performed, the RAM is rewritten. Thereby, a change in the emission data indicates a change or degradation of one or more of the LEDs. This enables one to forecast the life expectancy of the LED array, and maintenance of the printer becomes easier.
A method of checking a light emitting device having a plurality of light emitting elements, without removing the light emitting device from equipment using said light emitting device, said equipment having means for driving each of said light emitting elements and a target to be irradiated by radiation emitted from said light emitting elements, said emitted light defining an optical path, said method comprising the steps of:
A method for checking a light emitting device having a plurality of light emitting elements, without removing the light emitting device from equipment using said light emitting device, said equipment having means for driving each of said light emitting elements and a target to be irradiated by radiation emitted from said light emitting elements, said method comprising the steps of:
An apparatus for checking a light emitting device having a plurality of light emitting elements, without removing said light emitting device from equipment using said light emitting device, said equipment having means for driving each of said light emitting elements and a target to be irradiated by radiation emitted from said light emitting elements, said emitted light defining an optical path, said apparatus comprising:
An apparatus for checking a light emitting device having a plurality of light emitting elements, without removing the light emitting device from equipment using the light emitting device, said equipment having means for driving each of said light emitting elements and a target to be irradiated by radiation emitted from said light emitting elements, said apparatus comprising:
An apparatus, for checking a light emitting device having a plurality of light emitting elements, without removing said light emitting device from equipment using said light emitting device, said equipment having means for driving each of said light emitting elements and a target to be irradiated by radiation emitted from said light emitting elements, said apparatus comprising:
Dependencies are inferred from the claim text.