CHAPTER 2
delivery cover.
+5VDC is divided into +5V which is normally supplied to the ICs on the DC controller PCB from the power supply and +5V for power-saving mode (P5VB1). Supply of +5V for the power- saving mode is stopped when the sleep command is received from the video controller. During standby mode and periods when printing is not possible (when /RDY signal is “H”), the +5V is supplied OFF and ON.
The DC controller PCB generates +5VC and supplies it to the laser driver. This is shown in the block diagram below.
2. Protective Function
The +24VDC, +5VDC, and +3.3VDC power supply circuits have an over-current protective func- tion and over-voltage protective function, which automatically interrupt output voltage to pro- tect the circuits when a short circuit or other troubles on the load side result in over-current flow or abnormal voltage.
If the over-current/over-voltage protective functions are activated, and no DC voltage is out- put from the power supply circuits, turn OFF the power switch, rectify the trouble on the load, and then turn ON the power switch again. Wait at least for 2 minutes before turning the power switch ON again.
If over-current flows through the AC line, the circuit breaker in the power supply is turned OFF to cut off the output voltage.
