Canon LBP7210Cdn Manual page 86

When loading transparencies, labels, or coated paper, fan them a few sheets at a time, and
then align the edges.
CAUTION
Be careful when handling paper.
Handle paper carefully not to cut your hands with the edges of the paper.
IMPORTANT
Be careful when handling transparencies, labels, or coated paper.
Be sure to fan the transparencies, labels, or coated paper thoroughly before loading
them. If they are not fanned enough, multiple sheets of paper may be fed at once,
causing paper jams.
When fanning or aligning the transparencies or coated paper, try to hold the edges
to avoid touching the printing surface.
Take care not to mark or stain the printing surface of the transparencies or coated
paper with fingerprints, dust, or oil. This may result in poor print quality.
Gently load the paper stack under the load limit guides (A) until it touches the back of the
tray.
Make sure that the paper stack does not exceed the load limit mark lines (B).