Detecting The Level Of Color Toner - Canon iR C6800 Series Service Manual

Chapter 7

7.7.5 Detecting the Level of Color Toner

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The machine is equipped with 2 types of detection mechanism to monitor the level of color toner:
1. based on the reading of the video counter
2. based on the state of the scanner sensor
Detection by the Reading of the Video Counter
The machine computes the amount of toner consumption for individual colors based on the video data coming from
the main controller, and uses the result to find out the level of toner remaining inside the color developing assembly.
The machine runs a check for every color print, and keeps the result of detection in the memory of the DC controller.
The range of toner level is between 1% and 100% (in 1% increments).
Memo:
When the color toner starts to run out, the machine indicates the user message "Toner Running Short," with the level
of toner falling to 10%. (at time of shipment)
The timing of indicating the message may be changed in service mode (between toner levels of 5% and 10%):
COPIER>OPTION>BODY>T LW LVL.
Detention by the Optical Sensor
The machine uses a penetration type sensor (color toner level sensor; PS25) to check the presence/absence of color
toner; specifically, the DC controller monitors the state of PS25, which consists of a light emitting segment (LED)
and a light receiving segment (PD).
When printing starts, the DC controller generates the LED drive signal (CL_TNR_SNS_ON) to turn on the LED.
The light from the light emitting segment moves through the light guide mounted to the cartridge to reach the inside
of the toner cartridge. The light then moves through the toner cartridge and then along the light guide to reach the
light receiving segment, causing the color toner level detection signal (CL_TNR_REMAIN) to be sent to the DC
controller.
The DC controller, in turn, detects the presence/absence of toner using the toner level detection signal occurring as
the result of turning on the light emitting segment of the sensor.
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