Canon C2050 Service Handbook page 167

IMG-DT-Y/M/C/K
Image Ratio of Copy/Print Job (average of past jobs)
Use This data is used when setting the timing at which the following message is
indicated: "Prepare for the Replacement of the Drum Unit" and "Replace
the Drum Unit."
Reference If the image ratio for copy/print jobs is low, the drum unit will last so much
longer; in this respect, the timing of indication may be delayed for users
making copies/prints with a low image ratio.
CRY-AVE
Copy/print Job Count (average of past jobs)
Use This data is used when setting the timing at which the following message is
indicated: "Prepare for the Replacement of the Drum Unit" and "Replace
the Drum Unit."
Reference If the copy/print count is high, the drum unit will last so much longer; in
this respect, the timing of indication may be delayed for users using a high
copy/print count.
SERVICE MODE
COPIER>DISPLAY
S-25