Dell 1250c Color Laser Printer - Manual (Page 127)

Maintaining Your Printer 125
10 Replace the other three cartridges as well.
11 Close the toner access cover.
Cleaning the Color Toner Density (CTD) Sensor
CAUTION: To prevent electric shock, always turn off the printer and disconnect
the power cable from the grounded outlet before performing maintenance.
1 Ensure that the printer is turned off.
2 Push the rear cover release handle and open the rear cover.
Y Y