Toner Near End/End Detection; Standard Method; Adjustable Near-End Warning Method - Ricoh A-P3 Service Manual

DEVELOPMENT 6 November, 2001

6.7.6 TONER NEAR END/END DETECTION

Standard Method

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 be 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.
NOTE: 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 cartridge was installed. This allows the user to be prepared much
earlier than just 90 prints to change the cartridge. Refer to the SP table for more.
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