Canon GP160DF Service Handbook page 122

CHAPTER 4 SERVICE MODE
Remarks:
When the test print switch (SW401) on the sensor PCB is pressed, the print patterns
shown below are output.
By outputting these test prints, you can conduct a print check with the scanning
assembly Operation panel assembly installed.
Precision screwdriver
Figure 4-18
4-66
Print pattern
Figure 4-19