Power Supply System AC/DC Power Distribution AC power is supplied to the low-voltage power supply circuit in the Engine Controller Board when the power switch (SW1) is turned on. The low-voltage power supply circuit supplies +24 VDC and +3.3 VDC required for the printer. +24 VDC is supplied to drive the main motor, scanner motor and fan, and to the high-voltage power supply. +3.3 VDC is used for sensors and ICs on the engine controller board. +24 VDC is divided into +24 VA which is normally supplied from the low-voltage power circuit, and +24VB which is interrupted when the door switch (SW101) turns off by opening the upper cover.
Figure 5-1 Low-voltage Power Supply Circuit If a short-circuit or other problems on the load side cause an excessive current flow from the +24VDC, or +3.3 VDC power supplies or generate abnormal voltage, the excess-current protection system and excess-voltage protection system automatically shut off the output voltage to protect the power supplies. If the protection systems are activated and the power supply circuit does not output DC voltage, it is necessary to turn the printer off, correct the problem in the faulty load, then turn the printer on again. The circuit has two fuses which break the circuit and cut off the output voltage if excess current flows through the AC line.
5-2 Functional Information