Sony UP-860 Service Manual page 52

iINT-v
Synchronized
0 1 2 3 4 5 St 63 64 65
STB | f
To Th T2 Ts Ts Teo abo S Ta Te
64CLK | |
reow=~
CLK
= oo 19] Ee
608 Goer
eet
5.3MHz :
4th stair
Ast stair 2nd stair 3rd stair' Sth stair 6th stair 64th stair _—_
64 bits transferred for one block;
in all 14 blocks of data are sent in parallel
(640aTA x 14=896DaTA)
OR
Fig.5-10. Stair Generation
5-6-3. Basic operation
All the signals are input to head from IC102. This section only explains the
operations for one block. (The operations for the other blocks are the same.)
(i) The 64 data items of screen printing are input to the shift register
synchronized with CLK.
(ii) When the STB pulse is input, the data input in (i) is moved from the shift
register section to the latch section.
(iii) When the DR pulse is input, the output stage transistors are switched ON/OFF
by the "H" and "L" latch section data. While the transistors are on, the
resistors heat up and thermosensitive paper changes color. The amount of heat
generated is controlled by varying the length of the DR pulses, so the color
darkness of the printing on thermosensitive paper can be varied.
* Note: The BEO terminal goes from "L" to "H" only when the power is turned on.
After that it stays "H".
5-6-4. Stair generation
As explained in the last section on basic operation, the darkness of the printing
can be controlled with the DR pulses, but it is also possible to change the darkness
by changing the high and low data input to the latch section. This section explains
this method.
(i) The data recorded in the video memory, IC103 to 105, in the print operation is
input to the IC102 stair data generation circuit by 1H(1 line). [The stair data
generation circuit outputs the 6 bits of data recorded in IC102 as one of 64
levels. If the 6-bit data is "3", then DATA "H" is sent to the head during the
Ist, 2nd, and 3rd stairs of DATA 1 to 6 in Fig.5-10, but from the 4th stairs
and later, the DATA "L"is sent.
In this way, the screen is printed with the third stair, but from the fourth stair
and later is not printed.(See the explanation of the basic oerations in 5-6-3.)
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