Canon MX870 Series User Manual page 312

Note
The printer automatically reduces the print area depending on the staple position margin.
Complete the setup
4.
Click OK on the Page Setup tab.
When you execute print, the data is printed with the specified staple side and margin width.
Important
Staple Side and Specify Margin... appear grayed out and are unavailable when:
Borderless, Poster, or Booklet is selected for Page Layout.
Scaled is selected for Page Layout (When Duplex Printing is also selected, only Staple Side can
be specified).
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