LX-105O+
Service Manual
Operating Principles
2.3.2 Operating Principles of the Main Control Circuit
The printer CPU is an 8-bit CPU
~D7810HG
running at 15 MHz. It oversees control of all the
components of the printer. The
E05A30
gate array contains various memory management functions
that control the assignment of the memory and 1/0 areas.
CPU
vPD781OHG
(2C)
Bm
~c”’””’
E05A30
(3B)
E
Control Panel
Parallel l/F
I
CR
motor
driver

EIE

m
Figure 2-11. Main Control Circuit Block Diagram
Table 2-3 lists the functions of the components and circuits of the printer. The CPU converts the
print data sent from the host computer to image data (the print image). The image data is then
loaded to RAM. Each line of data is processed sequentially. The CPU transfers the print data to the
printhead
drive circuit. The CPU sends the
printhead
drive pulse to the
printhead
drive circuit. The
length of this pulse corresponds to the pnnthead drive voltage. The head drive circuit then outputs
the-head drive signal. -
Print
tl
Host
Data
Computer
+24V
line
L
Printhead
Drive
CPU
Data Input
Print Data
Convertor
I
1
Image Data
Transfer
RAM
Input
Buffer
+
Image
Buffer

L?ap’nthead

Figure 2-12. Data Flow
Rev.
A
2-9
II