Canon LBP6780x Manual page 149

The quality of paper may deteriorate if stored improperly even when the paper meets the normal specifications.
Inferior paper may cause misfeeds, paper jams, or deterioration in print quality.
How to store paper
Observe the following guidelines when storing and handling paper.
Store paper on a flat surface.
To help paper avoid moisture or dryness, keep paper in its wrapper until it is ready to be used.
Do not place paper in the condition where it may curl or become creased.
Do not store paper vertically or store too many stacks of paper in one pile.
Do not store paper in the following locations.
A location exposed to direct sunlight
A location subject to high humidity
A dry location
A location with a temperature or humidity that differs significantly from the location where it will be used
If you print on damp paper
If you print on damp paper, steam may be emitted from the printer output area.
This is due to moisture in the paper evaporating because of the heat generated when toner fixes. This is not a malfunction.
(This is likely to occur when the room temperature is low.)
Storing Printouts
When handling or storing paper printed by this printer, be careful of the following points.
How to store printouts
Store paper on a flat surface.
Avoid storing printouts in folders made of PVC material, as this may cause the toner to melt and stick to the PVC
material. Toner may peel when printouts are folded or creased.
Store printouts in the condition where they are not folded or creased as toner may peel.
Avoid rubbing the printed paper with fingers or cloth because it may cause toner stain or toner peeling.
Put printouts in a binder when storing for a long period of time (two years or longer).
Printouts may discolor when stored for a long period of time.
Avoid storing printouts in a location subject to high temperatures.
Precautions when sticking printouts with adhesive
Be sure to use insoluble adhesive.
Test the adhesive on an unneeded printout before using.
Before stacking printouts that have adhesive, check that the adhesive completely dried.