Canon MB2100 SERIES Online Manual page 176

• To load paper larger than A4 size, press the lock (G) and pull the cassette all the way out.
5. Align the front paper guide (A) with the stack.
The paper guide (A) clicks into place when aligned with a page size marked on the cassette.
6. Slide the right paper guide (B) to align the right and left guides with both edges of the stack.
Do not set the paper guides too firmly against the paper, which may cause feeding problems.
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