Id Sensor Operation During Machine Warm-Up - Ricoh Aficio 240W Service Manual

6.6.7 ID SENSOR OPERATION DURING MACHINE WARM-UP

Vsp/Vsg = 0.4/4.0 = 0.1 (Normal)
Vsg is checked one time only, when these two conditions occur at the same time:
• The machine is switched on with the main power switch or the operation switch
• The upper unit is closed.
At power on, the drum turns freely for 35 s to clean the surface of the drum against
the cleaning blade. When the machine makes the first copy after the power is
switched on, to calculate Vsp/Vsg it uses:
• The Vsg value measured immediately after power on.
• The last Vsp value measured before the machine was switched off.
After this, the machine uses the Vsg value measured immediately after the power
is switched on. But Vsp is measured after each copy.
The machine releases toner to the development unit when the value calculated for
Vsp/Vsg is more than 0.1. During standard operation, if Vsp/Vsg = 0.1 or less no
toner is supplied.
The timing chart on the next page shows the warm-up sequence. 'This sequence
occurs immediately after the machine is switched on. The machine measures
Vsp/Vsg during warm-up. This prevents dirty background on the first copies after
warm-up when hot roller temperature is less than 50°C.
NOTES:
• If SP2804 (Corona Wire Cleaning Interval) is set to clean the charge corona wire
during warm-up, Vsp/Vsg is measured after the wire is cleaned.
• SP2924 controls whether Vsg is measured during the warm-up sequence. For
more, refer to "4. Service Tables".
• If the machine is switched off and on after the warm-up sequence when Vsg is
less than 2.5V, the warm-up sequence is done; the setting of SP2924 (Warm-up
Control) is ignored.
SM
SW OFF
Vsp/Vsg = 0.4/3.0 = 0.13 (Add Toner)
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DEVELOPMENT
B125D960.WMF
B125