Xerox WorkCentre XK50cx Service Manual page 43

Circuit
4-2-1 HEAD CONTROL PART
GENERAL
It drives inkjet head to print printing data received
from the computer or copy an original. It roughly
consists of head driver, head
controller, and the ambient temperature sensor.
Fig.4-2-1. Block Diagram of Driver PBA shows the
entire structure.
HEAD DRIVER (U38, U39, U40, U41)
This part drives and inks inkjet head. Color inkjet
head drives 192 nozzles, while mono inkjet head
drives 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 (U38,
U39) selects head address and 16 column 8-bit
driver (U40, U41) sends head data. Head driver
converts control signals from MFP controller to
+12V, the level to be able to drive the head, and
provides them for the inkjet head.
• Row Driver Circuit (HD7:U38:U39)
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: 19KHz)
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 +12V.
• Column Driver Circuit (HD8:U40,U41)
It is the fire enable pulse of real head. 16 lines are
put out as head driving data lines through the
output port of MFP controller (HOE1 - HOE16).
Enable pulse impressed to the head is put out
within window time (Low). It has the function to
move it forward or backward by the register in MFP
controller. 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
voltage +12V.
4-16
HEAD CONTROLLER
This part consists of +22V Power Controller to
control head driver, Fault Test, Head Detection,
Substrate Heating and ambient Temperature
Sensor. It checks and controls head driver and ink
cartridge.
Refer to FIG 4-2-1