A dot printer has an LED array printer head consisting an array of LEDs, drivers for independently driving the LEDs, and time control circuits for controlling ON or OFF times of the LEDs by energizing the drivers in accordance with image data and correction data stored in a memory. The LEDs can be divided...http://www.google.de/patents/US4596995?utm_source=gb-gplus-sharePatent US4596995 - Dot printer having means for correcting intensity variations
