Electrical Circuit Operating Principles; C301Psb/Pse Board - Epson Stylus Photo 720 Service Manual

EPSON Stylus Photo 720 / EPSON Stylus Photo EX3

2.2 Electrical Circuit Operating Principles

The electric circuit of the Stylus Photo 720 / Stylus Photo EX3 consists of the
following boards.
Main board:
o
Power supply board:
o
Panel board:
o
This section provides operating principles of C301PSB/PSE Board and C301MAIN
Board. Refer to Figure 2-11 for the major connection of the three boards and their
roles.
C209PNL Board (Stylus Photo 720)
C366PNL Board (Stylus Photo EX3)
C301MAIN Board
3.3V Driver IC 5V Driver IC
3.3V Regulator
+5V DC
Power Off
C301 PSB/PSE
Board
Figure 2-11. Electric Circuit of Stylus Photo 720 /
Stylus Photo EX3
Operating Principles
C301MAIN Board

C301PSB/PSE Board

C209PNL Board (Stylus Photo 720)
C366PNL Board (Stylus Photo EX3)
Printer Mechanism
CR Motor
PF Motor
Head Driver Board
Several Sensors
+42V DC
Electrical Circuit Operating Principles
2.2.1 C301PSB/PSE Board
The power supply boards of Stylus Photo 720 / Stylus Photo EX3 use a RCC (Ringing
Chalk Converter) circuit, which generates +42VDC for drive line and +5VDC for logic
line to drive the printer. The application of the output voltage is described below.
Table 2-7. Application of the DC Voltages
Voltage
• Motors (CR Motor, ASF/Pump Motor, PF Motor)
+42VDC • Printhead common voltage
• Printhead nozzle selector 42V drive voltage
• C301MAIN control circuit logic
• C301MAIN IC16 3.3V generating regulator
+5VDC • C209PNL Board (Stylus Photo 720)
• C366PNL Board (Stylus Photo EX3)
• Sensors
Stylus Photo 720 / Stylus Photo EX3 uses the delay circuit (secondary side power
switch). Use of the secondary switch enables the circuit to keep supplying voltage to 5
V line and 24 V line for approximately 30 seconds if the printer power is turned off
through the panel switch. Even if the printer is turned off through the panel switch
while it is in operation, the printer turns the power supply off after performing the
capping operation to prevent ink leakage or dry printhead nozzles that may be caused
when the printhead is left without capping.
AC voltage input from AC inlet first goes through filter circuit that removes high
frequency components and is then converted to DC voltage via the rectifier circuit and
the smoothing circuit. DC voltage is then lead to the switching circuit and FET Q1
preforms the switching operation. By the switching operation of the primary circuit,
+42VDC is generated and stabilized at the secondary circuit. This +42VDC generated
by the secondary circuit is converted to +5VDC by the chopping regulator IC of the
secondary circuit.
Revision A
Application
42