LED-writer with improved uniform light output

摘要

The invention adjusts the calibration of each light emitting element, such as a light emitting diode (LED) by storing data representative of the difference between a linear or non-linear characteristic of the LED. In a printer or copier, a print engine uses LEDs to form a latent image on a photosensitive member. A linear regression identifies the differences between the slope of the individual LED and the average LED. A further, non-linear regression identifies the curvature of the individual LEDs. The differences in linear slope and/or curvature are stored and used to correct the calibration of each LED when the LED is recalibrated during operation and in response to a global calibration signal, GREF.