Method and apparatus for compensation of LED-array output power variation in electrophotographic printing
AssigneeMatsushita Graphic Communication Systems, Inc.
InventorsKiyoshi Futatsugi, Inui Yasuo, Mitsuo Mochizuki, Akira Hichijou
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Abstract
In a method and an apparatus for compensation of any variation that occurs in the output power or luminous energy of a LED array used in electrophotographic printing, the time for applying a current to one line of the LED array is optimally divided into a fundamental on-time for constant current application to the individual elements of the LED array and a compensational on-time for selective current application thereto in such a manner that the exposure values on a photosensitive medium become uniform.
Claims10
A method of compensating any variation in LED-array output power by controlling a current on-time for individual LED array elements in such a manner that the exposure values thereof on a photosensitive medium become uniform, said method comprising:
- determining a current on-time relative to one line of the LED array by setting a fundamental on-time for constant current application to the individual LED array elements and at least one compensational on-time for selective current application thereto;
- dividing the luminous energy distribution of said LED array into 2.sup.n parts where n represents the set number of the compensational on-time;
- and attaining a coincidence between the maximum and minimum luminous energies in each of the divided 2.sup.n parts of said luminous energy distribution.
A method of compensating any variation in LED-array output power by controlling a current on-time for individual LED array elements in such a manner that the exposure values thereof on a photosensitive medium become uniform, said method comprising:
- determining a current on-time relative to one line of the LED array by setting a fundamental on-time for constant current application to the individual LED array elements and at least one compensational on-time for selective current application thereto;
- dividing the luminous energy distribution of said LED array into 2.sup.n parts where n represents the set number of the compensational on-time;
- and minimizing the difference between the maximum and minimum values in the entire 2.sup.n parts of the luminous energy distribution.
Dependencies are inferred from the claim text.