Service manual

2.3.2.5 Printhead Driver Circuit
The printhead driver circuit for this printer is composed of the following two parts:
❒ Common driver circuit (common drive pulse generation)
❒ Head driver circuit (nozzle control built on the printhead)
The common driver circuit is hybrid IC H8D2778A on the C184 MAIN board. The head driver circuit is IC
SED61110D0A on the printhead unit itself. The printhead drive signals are output from gate array E05B21.
They consist of the common driver control signals (SBDT/SCDAT, SCLK,
SSTB, SCLR, BH1C0/CH1C0,
BH1C1/CH1C1, BH1D/CH1D, BHDIS/CHDIS) and the nozzle select signals (BHDAT/CHDAT,
BHCLK/CHCLK, BHLAT/CHLAT,
BHNCHG/CHNCHG).
The common driver control signals from gate array E05B21 are translated to common drive voltage pulses by
IC H8D2778A and input to each printhead nozzle PZT. The nozzle select signals are also output from gate
array E05B21 to SED6110D0A on the head unit to select the print nozzles. Then the ink dots are ejected from
the selected nozzles.
E05B21 (IC2)
COM
SED6110DOA
(U1)
CN11
C
N
1
LAT
CLK
SI
C184 MAIN
On Carriage (Head Driver Board)
SBDAT
SCLK
SSTB
SCLR
H8D2778A
BH1C0/1
BH1D
BHDIS
BHCLK
BHLAT
BHDAT
BHNCHG
SED6110DOA
(U2)
LAT
CLK
SI
H8D2778A
SCDAT
CH1C0/1
CH1D
CHDIS
CHCLK
CHLAT
CHDAT
CHNCHG
CN12
C
N
1
COM
Common Driver
Common Driver
Black Head Nozzles
Color Head Nozzles
Figure 2-6. Printhead Driver Circuit Block Diagram
Stylus Pro XL+ Service Manual Operating Principles
Rev.A 2-7