Trademark infringement is a violation of the exclusive rights of associated with a trademark without the authorization of the trademark owner and without any contractual or statutory licensee. Infringement may occur when one party, the "infringer", "accused" or "defendant", uses a trademark which is identical or confusingly similar to a trademark owned by another party, "owner", "plaintiff", "accuser", or "registrant"[if the mark is registered], in relation to products or services which are identical or similar to the products or services on which the owner uses the mark. The owner does not need a registration to sue you for infringement, sense trademark rights are based on use not registration in the USA. The owner of a trademark may sue someone that infringes its trademark. Registration gives certain benefits in such suits.
Outside the United States, trademark ownership is based on registration in most countries. In such a "registration" country, a trademark which is not registered cannot be "infringed" as such, and the trademark owner cannot bring infringement proceedings unless and until the trademark is registered. However, the owner may be able to commence litigation under the common law of "unfair business practices". In some jurisdictions, infringement of "trade dress" (the overall appearancespace or "get up" of packaging or store design) may also be illegal and is considered a form of trademark infringement. if you want to learn more about "trade dress infringement.", Google the term "Two Pesos Taco Cabana" and you will be able to review a leading case with excellent discussion of the law.
The standard for proving trademark infringement in the US and many foreign jurisdictions is whether there is a likelihood of confusion, meaning that consumers will be likely to be confused into believing the products or services originated from the trademark owner, were associated with the trademark owner, or were sponsored by the trademark owner. As you can appreciate, from the viewpoint of the trademark owner, when that happens the reputation of the trademark owner is no longer exclusively in the control of the trademark owner but rather is partially in the control of the infringer and thus the trademark owner loses the capacity to guarantee a certain level of quality that the owner desires that consumers associate with the trademark.
Likelihood of confusion is not necessarily measured by actual consumer confusion, though normally one of the elements, but by a series of criteria Courts have established. A prime example is the test announced by the Ninth Circuit Court of Appeals in AMF, Inc v Sleekcraft Boats, 599 F.2d 341 (C.A.9) 1979. The Court there announced eight specific elements to measure likelihood of confusion:
The most widely used test is a 13 factor test enunciated in the famous trademark case In re E.I. du Pont de Nemours & Co., 476 F.2d 1357, 177 USPQ 563 (CCPA 1973), known collectively as the DuPont factors.
Defenses: The party accused of infringement may be able to defeat infringement proceedings if it can establish a valid exception, such as:
Comparative advertising. Use of the trademark for purposes of comparing your product to the product bearing the trademark.
Nominative use. Use where necessary to describe the trademarked product or service. (e.g. you can find that at any Walgreen's store")
Laches & Estoppel. Where the trademark owner has delayed so long that the accused infringer is deemed to be justified in thinking the owner does not object or consents, and so consent is given by such inaction. Estoppel is where the trademark owner has not just failed to act, but has affirmatively done something that has made it unfair to allow the owner to subsequently sue for infringement. (e.g. where the owner has consented and then seeks to withdraw consent after the other party has detrimentally relied on the consent).
Prior Use by the Infringer.
If the respective marks and products or services are entirely dissimilar, trademark infringement may still be established if the registered mark is famous under the doctrine of "trademark dilution", particularly where the trademark owner has a wide variety of goods bearing the trademark or has a history of expanding the use of its trademark into new product areas. For example, even if SONY was not using the Mark SONY on a given product, Sony Corporation would not willingly allow that trademark to be used on any product whatsoever unless Sony Corporation approved. Likewise, Coca-Cola would not allow its famous trademarks to be used for free ison any product that was not licensed by Coca-Cola Corporation since they make millions of dollars licensing their brand.
In some jurisdictions a party other than the owner (e.g. a licensee, distributor, franchisee or major customer) may be able to pursue trademark infringement proceedings against an infringer if the owner fails to do so because such party may have a huge investment in the trademark in a given locality
WHAT IF YOUR TRADEMARK IS INFRINGED?
You should immediately seek a free initial consultation with a trademark infringement attorney. If the infringement is in another state, you will want to contact a trademark attorney that practices nationwide. Since Federal trademark registration is pursuant to Federal law, most trademark attorneys practice nationwide. Most trademark infringement attorneys offer a FREE initial consultation, so you would be foolish not to take advantage of it.
WHAT IF YOU ARE ACCUSED OF INFRINGEMENT?
The same thing applies. Immediately seek a free consultation with a trademark litigation attorney before you take any action or respond in any way to the accusation. This is much like the admonition usually given by a criminal defense attorney to not say anything. If you are not experienced in trademark litigation, you should not be making any statements about your case except statements to your own trademark attorney. Failure to heed this advice will almost certainly jeopardize your case. Also, realize that time is of the essence. Failure to respond in a timely manner may be taken by a court as an indication of willfulness in your infringement and that can result in punitive damages, injunctions and other bad things.