Canon CLBR 460ps Service Manual page 141

3. Paper size detection
The paper size and presence of the cassette are detected by the paper size detection switches
(SW801 to 803). Combinations of paper size detection switches are listed in Table 2-5-2.
Paper size
Legal
A4
Letter
Executive
B5
B5-ISO
A5
No cassette
The size of the paper set on the multi-purpose tray cannot be detected as the tray has no paper
size detection mechanism. The size of the paper set in the cassette can be detected with the
switches mentioned above. However, as the paper size is set by the user in case of the univer-
sal cassette, false detection may result from wrong setting by the user.
This printer detects the paper size by measuring time from refeeding (start of the registration
roller clutch (CL1) drive) until the trailing edge of the paper clears the registration paper sensor
(PS2). If the detected paper size differs from the size specified by the video controller or the above
mentioned switches, the DC controller assesses a paper size mismatch and reports it to the video
controller.
In case of duplex printing, if the PS2 detects small paper size that cannot be fed to the duplex-
ing unit, the M-CPU delivers the paper to the face-down tray.
Table 2-5-2
Cassette paper size detection switch
SW801 SW802
OFF OFF
ON ON
OFF ON
OFF ON
ON ON
ON OFF
ON OFF
OFF OFF
CHAPTER 2
SW803
ON
ON
ON
OFF
OFF
OFF
ON
OFF
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