Canon TR7660 Online Manual page 477

Note
• If the glass of ADF is dirty, black streaks appear on the paper as shown below.
Make sure original is properly loaded on platen or ADF.
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When you load the original on the platen, load it with the side to be copied facing down.
When you load the original on the ADF, load it with the side to be copied facing up.
Loading Originals
Is copy source a printed paper by printer?
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If you use a printout done by this printer as the original, print quality may be reduced depending on the condition
of the original.
Print from the printer directly, or reprint from the computer if you can reprint from it.
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