EPSON Stylus COLOR 3000

2.3 Electrical Circuit Operation Principles

This printer consists of the following circuit board:

￿C203 MAIN board

￿C178 PSB/PSE board

￿C203 Panel board

Head driver circuits are directly attached to the black and color printheads. Figure 2-13 shows the block diagram of the electrical circuit.

 

C203 PNL

 

 

C172 PSB/PSE

C203 MAIN

Printer Mechanism Unit

 

 

+5VDC

 

CR/PF/Pump

+42VDC

 

Motors

 

 

 

 

 

 

CR Unit

 

 

Color Head

Black Head

 

 

Driver Circuit

Driver Circuit

Figure 2-13. Electrical Circuit Block Diagram

2.3.1 C172 PSB/PSE Electrical Circuit Board

The output voltages of the PSB/PSE board are as shown in Table 2-7. Since the electrical circuit of this printer is in a secondary circuit, the delay timer can be used to allows the printer to execute the capping operation after the printer power is turned off. This is to prevent ink clogging or smudging caused by the exposed condition of the printhead.

 

Table 2-7. DC Voltage Distribution

 

 

 

VDC

 

Application

 

 

 

 

 

 

+42 V

 

￿ ￿￿ motor/￿￿ motor

 

￿ Printhead common voltage

 

 

+5 V

 

￿ C￿￿￿ MAIN control board (logic)

 

￿ Sensors

 

 

￿ Control panel, Head nozzle selection

 

 

 

The electrical circuit of this board uses the ￿￿￿ (Ringing Choke Converter) switching regulator. ￿￿ voltage is first input to the filter circuit for higher harmonics absorption and is converted into ￿￿ voltage thorough the rectifier and smoothing circuits. The ￿￿ voltage is then input to the switching circuit. These operations are followed by the transformer which generates and stabilizes +42 ￿￿￿ in the secondary side. The produced +42 ￿￿￿ is then converted into the stable +5 ￿￿￿ by the regulator IC. The ￿￿ on the ￿￿￿￿ !￿"# board monitors the on/off signal from the power switch on the control panel. When the power switch is turned off, the ￿￿ sends the ￿￿￿￿￿ ￿￿￿ signal (PSC) to the electrical circuit. The electrical board has a delay circuit (ZD86, C82 and Q84) to delay the power off. The delay period depends on the electrolytic capacitor. It continues to output +5 V and +42 V to keep the main circuit switch on the primary side active until all electric charge is discharged. The minimum delay period is normally 30 seconds, which ,however, varies depending on the capacitor size.

Rev. A

2-13