Canon imagePROGRAF iPF5000 Series Service Manual page 77

Valve open/closed detection sensor
The photo-interrupter-type valve open/closed detection sensor detects the valve cam state.
When the link that operates in conjunction with the valve cam shields light, this sensor detects that the ink supply valve has been opened.
Ink detection sensor
Presence of absence of ink in the ink tank is detected according to whether the two hollow needles are electrically connected.
When the ink level in the ink tank lowers below the wall around the hollow needle at the air passage, this hollow needle is electrically disconnected form the hollow
needle located on the ink supply side, thus detecting that the printer has run out of ink.
Head management sensor
The photo-transmission-type sensor detects that the printhead is discharging ink.
The carriage moves to and stops at the detection positions for individual nozzle arrays. When the carriage is at a stop, nozzles discharge ink on after another.
The sensor detects each nozzle due to the voltage change caused when ink discharged from the nozzle blocks the sensor light.
Sensor
F-2-51
Ink tank
Needle (ink supply)
F-2-52
Printhead
Nozzle unit
Head management
sensor unit
F-2-53
Slits
Wall
Rubber plug
Needle(air passage)
Chapter 2
2-37