Patent ID: 6100913
Filing Date: 2000-08-08
Classification: B41J,G06K

Abstract:
A method of correcting an amount of light emitted from each of a plurality of light emitting elements, comprising the steps of;measuring the amount of light emitted from each of the plurality of light emitting elements and determining a minimum value and a maximum value thereof;defining a first correction reference on the basis of the amount of light emitted from each of the plurality of light emitting elements;defining a first correction range having an upper limit and a lower limit, the first correction reference being substantially in the middle of the first correction range, the first correction range including a predetermined number of first sub-divided ranges between the upper limit and the lower limit, the first correction range being such that a first difference between the first correction reference and the amount of light emitted from each of the plurality of light emitting elements in the first correction range falls within a first predetermined range;determining whether the minimum value of the amount of light is within the first correction range;wherein if the minimum value of the amount of light is within the first correction range, the method further includes the steps of:determining a first correction value for each of the corresponding first sub-divided ranges, the first correction value being such that the first difference between the first correction reference and the amount of light emitted from each of the light emitting elements in the first correction range after correction is within a second predetermined range; andcorrecting the amount of light emitted from each of the light emitting elements in each of the first sub-divided ranges in accordance with the first correction value;wherein if the minimum value of the amount of light is not within the first correction range, the method further includes the steps of:defining a second correction range, the second correction range being defined by shifting the first correction range toward the minimum value by a predetermined quantity, the second correction range having a predetermined number of second sub-divided ranges and a second correction reference which is obtained by shifting the first correction reference by the predetermined quantity toward the minimum value;determining a second correction value for each of the second sub-divided ranges, the second correction value being such that a second difference between the second correction reference and the amount of light emitted from each of the emitting elements in the second correction range after correction is within the second predetermined range; andcorrecting the amount of light of each of the light emitting elements in each of the second sub-divided ranges in accordance with the second correction value.