Oki PAGE 18, Service Manual, Page: 49 / 395

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Service Guide OKIPAGE 18/18n
Chapter 2 Operation Description
2.3.4 Revision of LED Head Illumination
An LED correcting head, which is capable of correcting the illumination of the LED for each dot, is being used in this
printer. LED illumination correction function of 16 steps is carried out by using an EEPROM which is installed in the
LSI that maintains the LED illumination correction values, and an LED correction drivers together as a pair.
The LED correcting head consists of the correction control LSI , LED drivers , and an LED array.
The block diagram of the LED correcting head is shown below.
(1) Both sides wire-bonding head
In OKIPAGE 18/18n, the correction control of LED head is executed directly by the CPU.
The procedure is as follows
(i) LED head is set to the correction control read mode and all correction data stored in EEPROM within the
correction control LSI are read by CPU, and stored temporarily in the memory.
ii) Next LED head is set to the correction control direct mode and the correction data stored temporarily in the
memory is transferred directly to the LED driver.