Oki OKIOFFICE84, Maintenance Manual

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R51
A3 - 7 40672201TH Rev. 4
A3.1.6 R51 Circuit Diagram (Page 6/12)
1. Block diagram
The circuit diagram shown on page 6/12 consists of connector CN12 that provides an
interface between R51 board and LED print head.
Figure A3.1.6 shows the related signals and block diagram of LED print head.
2. Function
Data of 1664 LEDs on the LED print head is loaded into the shift registers by the HCLCK
(4MHz or 6.7 MHz) signal. After the 1664 bit (208 mm) data is loaded in the shift regis-
ters, it is then loaded in the latch circuit by the HLATCH signal. The turning -on and off of
the LEDs are controlled by STRB1-N to STRB4-N signals.
LED head interface signals output from IOGA4
•
HDATA 0 : Print data i.e., data to be printed
• HCLCK : Transfer clock for print data (4.0 MHz or 6.7 MHz)
• HLATCH : Latch signal for print data
• STRB1-N to STRB4-N : LED head strobe signals
Shift register
Latch
Strobe
CN12
8
6
9
10, 11, 12, 13
1, 2
3, 4
5, 14
+5 V
0 V
LED
1664 bits (208 mm)
LED print head
R51
HCLCK (1.0 MHz)
HDATA 0
HLATCH
STRB1-N to STRB4-N
0 VP
+5 V
0 V
IOGA4
IC2
Figure A3.1.6 Related Signals and Block Diagram of LED Head