What can be patented? It's a question of novelty: copies of patents referenced here are available from the Patent and Trademark Office, Box 9, Washington, DC 20231 or through www.uspto.gov for US$3.00 each.

Editor's Note: This column is a continuation of the Patent Corner articles appearing in TAPPI JOURNAL.

What requirements must be met in order to obtain a patent on an invention? Previously we have learned that inventions must fit into at least one of the statutory classes: a process, machine, an article of manufacture, or a composition of matter.

Other requirements for patentability include the following:

* The invention must be "useful."

* The invention must be "novel" (new or different).

* The invention must be "unobvious" to a person of normal skill in that particular technology area.

This month we will explore the second requirement, novelty.

On the face of it, novelty means only that your invention is new or different from any already known. In fact, your invention can be considered novel if it has:

* a new physical feature or process step,

* a new combination of separate old features or process steps, or

* a new use of an old invention.

In the previous Patent Corner example, a maintenance technician's new chipper blade holder invention uses a novel J-shaped groove, which locks the blade to the holder better than previous designs. The new groove shape would satisfy the novelty requirement because it is different from other shapes known or in use.

A papermaker's discovery that using a high concentration of a previously known defoamer as an additive improves fiber retention is an example of a "new use" of an existing invention and fulfills the novelty requirement.

In actuality, any difference between your invention, as claimed, and previously known "art" can be sufficient to satisfy the novelty requirement. Even slight differences between your invention and previous ones can be sufficient to satisfy the novelty requirement. However, your patent application would be rejected if held to be obvious (see the third requirement above). In other words, the examiner may reject patent application, saying that the slight difference is obvious to a person skilled in that particular technology area. The next Patent Corner will explain the obviousness requirement in more detail.

How can you determine if your invention is actually novel or different from previous inventions? A patent search, usually performed by a professional searcher, compares the novel aspect(s) of your invention to other issued U.S. patents and published applications. Your patent attorney or agent then evaluates the patents uncovered in the search to determine which aspects of your invention should be considered novel.

For economic reasons, many searches include only issued U.S. patents and published applications because many, if not most, existing inventions are disclosed in these sources. However, a published disclosure or public use of an invention in any country could potentially be cited against your invention, so a more extensive search may be appropriate.

The patent search allows your patent agent or attorney to fine-tune the patent application and ensure the novel features of your invention are identified and claimed.

The patent shown at left acknowledges prior use of PTFE strips embedded in suction roll seals. What is novel about this invention is its use of silicone oil and of PTFE powder dispersed within a composite that also includes nitrile rubber, carbon black and graphite. The resulting composite seal strip reduces the coefficient of friction against the inside surface of the suction roll shell, improving seal life.

This suction roll patent discloses a seal material made of a new combination of known materials; therefore, it is considered novel.

Ken Watkins is a Registered U.S. Patent Agent based in Dahlonega, Georgia, USA. Phone: [phone]. Email questions to [e-mail]