Samsung SF4500, Service Manual

Page: 45 / 130

6-14 Samsung Electronics
6-1-5 Printer
6-1-5-1. GENERAL
It drives inkjet head to print printing data re c e i v e d
f rom the computer or fax data coming through the
line. It roughly consists of head driver, head
c o n t ro l l e r, and the ambient temperature sensor. Fig.6-
1 - 11. Block Diagram of Printer shows the entire stru c-
t u re .
6-1-5-2. HEAD DRIVER (U26, U27, U32, U22)
This part drives and inks inkjet head. Color inkjet
head drives 192 nozzles, while mono inkjet head dri-
ves 208 nozzles. Mono inkjet head is composed of 16
g roups of 13 nozzles. As to the driver that composes
each nozzle, 13 row 7-bit driver (U26, U27) selects
head address and 16 column 8-bit
driver (U32, U33) sends head data. Head driver
converts control signals from MFP c o n t roller to
+ 11 . 7 5 V, the level to be able to drive the head, and
p rovides them for the inkjet head.
• Row Driver Circuit (HD7:U26:U27)
This is a 13-line signal impressed to row drive IC
t h rough the output port of MFP c o n t ro l l e r ( / H G A 1
- /HGA13), used as an address to drive the head in
ink cartridge. Pulse period differs according to
head driving
f re q u e n c y. In 1200dpi (in case of Head: 12KHz)
mode, timing period is 2.6usec (1/1200÷16 gro u p s ) .
The signal put in each driver(window time) is
active “L”, with the biggest driver current max
1 0 0 m A and output v11 . 7 5 V.
• Column Driver Circuit (HD8:U32,U33)
It is the fire enable pulse of real head. 16 lines are
put out as head driving data lines through the out-
put port of MFP c o n t roller (HOE1 - HOE16).
Enable pulse impressed to the head is put out with-
in window time (Low). It has the function to move
it forward or backward by the register in MFP c o n-
t ro l l e r. Besides the output signal may
d i ffer in accordance with the type of head (mono or
color). If there is data, printing image is put out at
“H”. If not, it is put out at “L”. In case of Babbage
head, pulse width is always 1.3use re g a rdless of
the type of the head, with the
maximum driving current 400mAand output volt-
age +11 . 7 5 V.