Dell 1815dn Multifunction Mono Laser Printer - Manual (Page 131)

The paper storage environment should be properly maintained to ensure optimum performance. The required condition is 20° C to 24° C (68° F to 75° F), with
a relative humidity of 4 percent to 55 percent. The following guidelines should be considered when evaluating the paper's storage environment:
l Paper should be stored at or near room temperature.
l The air should not be too dry or too humid.
l The best way to store an opened ream of paper is to rewrap it tightly in its moisture-proof wrapping. If the printer environment is subject to extremes,
unwrap only the amount of paper to be used during the day's operation to prevent unwanted moisture changes.