Canon MultiPASS C50 Service Manual page 96

Part 1: Facsimile
Ink empty detection
Ink empty detection during fax operation is performed by firing black ink between the light
source and receptor of the ink sensor, located on the left side of the printer. This function
does not work with the BC-22, only with BC-21 or BC-20.
NOTE
When ink passes between the source and the receptor, as shown in Figure 2-10 , the sensor
output will be a pulse waveform. The presence of ink may be determined from the pulse
generation time.
Ink empty detection is performed at the end of each received page of printing. If ink is not
detected on the first detection attempt, the ink nozzle is shifted slightly, and the detection
operation is repeated to double-check the first detection operation. If it is determined that
there is ink remaining, the image data for that page will be erased from memory. If the
cartridge is out of ink, the message "CHANGE CARTRIDGE" will be displayed to inform
the user that the cartridge is out of ink, and the page will be "received" to memory again
from the image data.
The detection level of the ink detection sensor is adjusted automatically by means of a
feedback circuit, and thus requires no manual adjustment. If the sensor output does not
reach a standard level, even after performing feedback control (such as if the receptor is
completely blocked, or if a sensor defect occurs), the ink sensor failure will be reported with
the display of the "CHECK PRINTER" (error code ##348) message.
B J
C a
r t r i
Signal sends to
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e
PCNT board
Ink detect sensor
Figure 2-10 Ink Empty Detection
2-16