Canon MultiPASS C5000 Service Manual page 84

Part 1: Facsimile
NOTE
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.
When ink passes between the source and the receptor, as shown in Figure Z-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 "REPLACE 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.
Figure 2-10 Ink Empty Detection
Signal sends to
PCNT board
Ink detect sensor
2-l 6