Samsung SF-4500 Service Manual page 45

6-1-5 Printer
6-1-5-1. GENERAL
It drives inkjet head to print printing data received
from the computer or fax data coming through the
line. It roughly consists of head driver, head
controller, and the ambient temperature sensor. Fig.6-
1-11. Block Diagram of Printer shows the entire struc-
ture.
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
groups 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 controller to
+11.75V, the level to be able to drive the head, and
provides them for the inkjet head.
• Row Driver Circuit (HD7:U26:U27)
This is a 13-line signal impressed to row drive IC
through the output port of MFP controller(/HGA1
- /HGA13), used as an address to drive the head in
ink cartridge. Pulse period differs according to
head driving
frequency. In 1200dpi (in case of Head: 12KHz)
mode, timing period is 2.6usec (1/1200÷16 groups).
The signal put in each driver(window time) is
active "L", with the biggest driver current max
100mA and output voltage +11.75V.
6-14
• 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 controller (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 con-
troller. Besides the output signal may
differ 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 regardless of
the type of the head, with the
maximum driving current 400mA and output volt-
age +11.75V.
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