• Vt = 0.5 volts or lower
• Vt = 4.0 volts or higher
Then SC340 (TD Sensor Output Error) is logged.
Abnormal ID Sensor Output
Abnormal output detected during process control at power-on: SC353 or SC354 is issued. Toner supply
during copying will then be controlled using the TD sensor only, until the machine is repaired.
Abnormal output detected when updating Vref: SC350, 351, or 352 is issued, and Vref is not updated
(the machine uses the current value).
Toner End Detection
The toner end sensor is checked every copy.
• Toner near end. When the toner end sensor remains on for two consecutive pages, the toner supply
motor turns on for 1.1 s. If the toner supply motor has turned on more than 30 times during the last
100 prints, the “Toner Near End” warning is issued. The warning is cleared if the toner end sensor
turns off.
• Toner end. If the toner end sensor remains on for about 1,000 copies (A4 size with 6% coverage),
the "Toner End” warning is issued. If the toner end sensor switches off twice consecutively, the toner
end sensor copy counter is reset to zero.
Toner End Recovery
If the front door is opened and closed while a toner near end or toner end condition exists, the machine
attempts to recover using measurements from the toner end sensor and TD sensor, based on the possibility
that the toner bottle has been replaced.
1. The drum development motor, charge grid, and development bias switch on.
2. The toner supply motor switches on for 1.1 s, the toner supply clutch switches on for 1 s, and the CPU
checks the toner end sensor output.
3. If the toner end sensor is OFF, i.e. there is toner in the hopper, the CPU compares Vt and Vref.
• If Vt is less than or equal to Vref, there is sufficient toner in the development unit. The CPU waits
20 s for the toner in the developer to mix evenly, the above components switch off, and the
machine is released from the toner end or toner near end status.
• If Vt is more than Vref, the CPU turns on the toner supply clutch for 1 s again until Vt becomes
less than or equal to Vref.
• If the toner end sensor output remains on even after seven attempts of the above procedure, the
components switch off and the machine remains in the “Toner End” status.
6. Details
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