Canon BJ-20 User Manual page 26

The printer starts printing a test page (Ripple Pattern Test).
5
A sample portion of the test page is shown below. If any printing problem
occurs, see chapter 7 on troubleshooting.
Ripple Pattern Test in BJ-10e mode
Self-test is completed when a full page of the test pattern is printed.
6
To suspend the test before it ends.
Press the LF/FF switch. To resume, press the switch again. When the test is
suspended (the ON LINE indicator blinking), you can, for example, press
the ON LINE switch to turn the printer online; but if you do so, you cannot
return to the test again, without starting from step again.
To quit the test before it ends.
Press the ON LINE switch. To remove the paper, press the ON LINE
switch to turn the printer offline, then press the
LF/FF switch.
Notes
In step 1, if you hold down the PITCH switch (instead of
the LF/FF switch), the printer will print a sample in each of
the following pitch and style (All Modes Test) using courier
font.
HQ proportional