Ricoh A-P4, Service Manual

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changed over to image pixel count mode with SP2208-01 (Toner Supply Mode) remain in effect and
cannot be changed.
Toner Near End/End Detection
Standard Method for Toner Near-End/End Condition Detection
The toner near-end condition is detected based on the Vt(10) output from the TD sensor.
• If the difference between Vref (toner supply reference voltage) and Vt (10) is less than or equal to –
0.45, then toner concentration is judged as very low and K (the toner supply coefficient) is set to 0.25,
the machine enters the toner near end condition and the machine switches on the toner supply motor.
• If a difference greater than –0.45 is detected, then toner concentration is judged as low but the
machine does another test by comparing Vref and Vt (10).
• If the machine determines that Vt (10) is greater than Vref 40 times, the toner supply motor switches
on and remains on for twice the time that Vt (10) was greater than Vref. If the toner concentration is
still low, then the machine enters the toner near end condition.
The final toner end is detected using the ID sensor. If the ID sensor detects that the ID sensor pattern is very
light (Vsp drops below 2.0 V), then the sensor triggers the toner end condition.
If Vsp is less than 2.0 V, the density of the ID sensor pattern is very light, so the machine detects the toner
end condition. However, if Vsp remains higher than 2.0 V but 90 copies have been made after toner near
end was determined, the machine enters the toner end condition.
• The number of copies between toner near-end and toner end can be changed with SP2213. The
default is 90 copies.
Adjustable Near-end Warning Method
By storing a value in SP2975, a near-end warning can be set up to appear on the LCD when the toner
supply motor has rotated for a certain amount of time from after a new toner bottle was installed. This allows
the user to be prepared much earlier than just 90 prints to change the bottle. Refer to the SP table for more.
Toner End Recovery
If the front door is opened and then closed while a toner near end/end condition exists, the machine will
attempt to recover. When the front door is closed, the toner supply motor turns on to supply toner. The
machine checks the TD sensor output 2 seconds after the main motor turns on (Vtp), and the sensor is
checked again every 1 second (Vtp1)
Development
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