Canon LBP7210Cdn Manual page 303

Specify the settings for [Page Size] and [Output Size].
(1) Display the [Page Setup] sheet.
(2) Select the page size of the document created by an application.
(3) Select the size of the paper loaded in the paper source as needed.
Specify the scaling factor.
(1) Select the [Manual Scaling] check box.
(2) Specify the desired scaling factor.
Confirm the settings, then click [OK].
The [Print] dialog box reappears.