When is Use of a Trademark an Infringement?

The key issue in determining infringement is whether there is a likelihood of confusion caused by the alleged infringer’s use of the owner’s mark (or something similar). The courts look at several factors in assessing likelihood of confusion. The factors are:

• The strength of the mark. Is the mark well-known? Has the owner devoted much time, money and effort to publicize the mark? How closely is it associated with the owner and its products and services?
• The degree of similarity between the mark and the thing alleged infringer is using–how close are they in appearance, meaning or sound?
• The proximity of the parties’ products–are they in the same product category? Do they
  use the same channels of distribution?
• The likelihood that, if the parties’ products do not directly compete, they will sometime in the future ‘bridge the gap’ that currently exists.
• Actual confusion. Is there anecdotal evidence of confusion? Does the owner have a survey of consumers demonstrating confusion?
• The intent of the defendants–did defendant know of plaintiff’s mark? Did defendant
  deliberately copy plaintiff’s mark?
• The quality of the products–is defendant’s product clearly inferior to plaintiff’s?
• The sophistication of the purchasers–are they discerning or careful enough that confusion is unlikely?

The court will balance these factors, and a trademark plaintiff need not prevail on each of them to succeed on its claim. For example, actual confusion is not required. Malicious intent is not required–a defendant who acts in complete good faith may still be prevented from using its own mark. Generally, and as one might expect, courts use common sense in balancing the relevant factors.