TONER DENSITY DETECTION AND TONER SUPPLY15 January 1992
6. TONER DENSITY DETECTION AND TONER
SUPPLY
6.1 OVERVIEW
Original Lead
Sensor
Edge
Pattern
Original
ONOFFONOFF
Development
Leading EdgeID SensorBias
ABCDEPattern
Erase
RAM Clear
1234567891011121314202122
Toner Density DetectionToner Density DetectionToner Density
Detection
1st2nd3rd
Low Toner Density
Toner Supply Timing
Detection
Toner Add
Toner Supply Clutch ONDetection
(10 times)
The CPU checks toner density by directly sensing the image density every 10
copy cycles. If the RAM is cleared (SP99), or a new RAM is installed, the
CPU checks the image density at the beginning of the first copy cycle.
During the check cycles, the sensor pattern is exposed prior to the exposure
of the original. After the sensor pattern is developed, its reflectivity is checked
by the image density sensor (a photosensor). The CPU notes the reflectivity
and if the reflected light is too strong, indicating a too low toner density
condition, toner is added to the development unit.
The toner is not added all at once. The CPU will energize the toner supply
clutch for the proper amount of time in order to add a selected amount of
toner over the next 10 cycles.
When the free run mode (turn DIP switch 101-1 ON) is selected, the CPU
checks the toner density every copy cycle.
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ACEC
RICOH
