Protective Functions; High-Voltage Power Supply Circuit; Controlling The Ess Mechanism; Outline - Canon SmartBase 1270D Service Manual

7.1.2 Protective Functions

The power supply PCB is equipped with an over-current/over-voltage protection mecha-
nism to prevent damage to the power circuit in the event of an over-current or over-voltage,
as caused by a short circuit or the like on the load side. If the over-current/over-voltage pro-
tective mechanism has gone ON, disconnect the power cord, and correct the fault; then, con-
nect the power cord once again to reset the machine. If short circuiting and resetting are re-
peated, the internal fuse (F1, F2, F101) can melt.

7.2 High-Voltage Power Supply Circuit

The high voltage output circuit is built into the DC controller PCB.
The CPU on the DC controller PCB sends instructions for the generation of the following
high voltages at specific timing:
• primary charging roller bias (AC voltage + DC negative voltage)
• developing bias (AC voltage + DC negative voltage)
• transfer charging roller bias (DC positive voltage or DC negative voltage)

7.3 Controlling the ESS Mechanism

7.3.1 Outline

The machine is equipped with an ESS mechanism to limit the consumption of power in
standby as much as possible. The ESS function is controlled by the image processor PCB,
and the machine shifts to ESS mode when the Energy Saver key in the control panel is
pressed or the machine remains in standby state for a specific period of time.
The standby period after which the ESS mode is started is set in user mode: 3 to 30 min
(factory default: 5 min).

7.3.2 Operation

While the machine remains in ESS mode, all in the control panel except the LED indica-
tor of the Energy Saver key will remain OFF. The machine will not shift to ESS mode under
any of the following conditions:
• The shift to ESS mode is not enabled in user mode.
• A jam or a service error occurred, and the Alarm lamp is ON. (In the case of the ab-
sence of toner or paper, the machine shifts to ESS mode in the absence of paper.)
• The image memory contains image data.
While the machine is in ESS mode, it will shift out of the state in response to a press on
the Energy Saver key; in addition, it will automatically shift out of the state under any of the
following conditions:
• Print data arrives from the PC.
• A fax arrives.
• Off-hook state is detected.
• A report output time occurs.
• A timer call time occurs.
*1: Only if equipped with fax functions.
COPYRIGHT © 2002 CANON INC.
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2000 2000 2000 2000 CANON SmartBase PC1210D/1230D/1270D REV. 1 MAR. 2002
CHAPTER 4 OPERATION
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