Toner Level Detection - Canon imageRUNNER 2270 Service Manual

Chapter 7

7.8.6 Toner Level Detection

Detecting the Level of Toner Inside the Sub Hopper
The machine checks the level of the toner sensor located inside the sub hopper every 100
msec, and will assume the presence of toner inside the sub hopper if the sensor goes on
twice or more continuously (200 msec or more).
If the machine detects the absence of toner 100 times or more (10 sc or more) as the result
of its check on the sensor level made every 100 msec, the machine will assume that there is
no toner inside the sub hopper.
The machine executes the foregoing detection at all times regardless of the state (on or off)
of the main motor and the developing clutch.
Detecting the Level of Toner Inside the Developing Assembly
1. The machine samples the output of the toner level sensor located inside the developing
assembly every 100 msec (only if the developing clutch is on).
2. The machine uses a period of 1.5 sec (15 times; cumulative sampling of periods when the
clutch is on) as the unit of measurement: if the presence of toner is detected 3 times or
more, it will assume that there is toner inside the developing assembly; if the presence of
toner is detected less than 3 times, on the other hand, it will assume that there is no toner
inside the developing assembly.
However, in the case of the iR3570/iR4570 Series machines, the drive of the main motor is
controlled to 2 different speeds, and the toner inside the developing assembly is driven by
the main motor (using a clutch), requiring a switchover of methods of detection as follows:
Normal Speed Mode
The machine uses a period of 1.5 sec (25 times; cumulative sampling of periods when the
clutch is on) as the unit of measurement: if the presence of toner is detected 3 times or more,
it will assume that there is toner inside the developing assembly.
Low-Speed Mode
The machine uses a period of 2.5 sec (42 times; cumulative sampling of periods when the
clutch is on) as the unit of measurement: if it detects the presence of toner 5 times or more,
it will assume that there is toner inside the developing assembly.
The machine converts the number of samplings and the number of times toner detection has
been executed when switching over methods of detection. (The conversion is based on the
speed-to-amount relationship.)
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