Canon MP 700 Service Manual page 30

The sensors detecting document/paper-fedding condition or ink presence/absence are mounted.
Carriage encoder film:
Detects the state of carriage unit.
Paper feed encoder film:
Detects the state of paper feed roller
MultiPASS MP730/MP700 Chapter 2: Technical Reference
Document edge sensor (MP730 only)
Detects the trailing edge of the document.
Document sensor (MP730 only)
Detects whether or not a document is set.
Cover sensor:
Detects the state of flatbed unit
Ink sensor:
Detects that there is
no ink in the inkchamber
Figure 2-3 Sensor Layout
2-3
Paper edge sensor:
Detects the state of
paper feeding and deliverry.
ASF sensor:
Detects the state of ASF
Purge sensor:
Detects the state of
purge unit