It is important that the filter is glued in front of the air outlet. However, many laser printers have multiple openings, not every one of which is an air outlet. To find out if you have the correct opening in front of you, please proceed as follows:

• Take a small piece of thin string
• Print several pages directly one after the other so that the fan starts up
• Hold the string in front of the openings
• Where the string is blown away from the fan is where the air outlet is located