by Dennis Crouch
In an earlier post, I wrote about the Code of Federal Regulations’ requirement that patent claims “should” be drafted in Jepson form. 37 C.F.R. 1.75(e). This claim structure uses the preamble to particularly identify the elements of the invention known in the art with the body simply reciting the “portion of the claimed combination which the applicant considers as the new or improved portion.” In my view, Jespon claims are so nice to read because they actually spell out what has been improved by the invention. Unfortunately, they also are seen as increasing the chance that the patent will be both narrowly interpreted and found invalid – and that the statement regarding the prior art will be seen as an admission. For much these same reasons, most patents no longer particularly identify their “invention” beyond stating that it is embodied by each claim taken as a whole. Prof. Kayton, who trained generations of patent attorneys in his PRG classes was particularly adamant about avoiding Jepson claims.
Gene Quinn on his blog writes “No patent attorney in their right mind would follow this suggestion.” (referring to Rule 1.75(e)). While I largely agree that Jepson claims are problematic for the reasons stated above – I would caution patent attorneys to ensure that their ethical guidelines are being met. In particular, when the law says that attorneys “should” do something, it seems improper to entirely ignore the law’s suggestion. Rather, the patent attorney should consider – as stated in the Rule – whether “the nature of the case admits” such a claim form. An additional ethical trick when thinking through this is to consider whether a family-member patent claim has already been (or will be) filed in a separate jurisdiction that requires this form.
In a 2009 post, Aaron Feigelson reported some interesting data on the use of Jepson claims in the US. Essentially that its use had dropped tremendously as shown by Feigelson’s chart below (reproduced with permission).
Feigelson’s data just ran through 2009 and may actually overstate the prevalence of Jepson claims because he includes any patent with the word “improvement” in the claim. I just updated the data up through 2017 with the chart shown below – looking for patents having at least one claim with the following phrase “the improvement compris.” As you can see, less than 1 out of every 1,000 newly issued patents is in this claim form. 
The most recent patent with a Jepson claim is U.S. Patent No. 9,744,559 covers the use of nanoparticle materials for “high contrast surface marking,” and is only found in Claim 24.
24. In a thermally activated, chemically based marking method comprising the steps of:
applying a layer of a marking composition to the surface of a substrate and irradiating said layer with radiant energy which is absorbed by at least one component of said marking composition,
the improvement comprising the use of marking compositions comprising amounts of at least one pigment encapsulated in silica nanoparticles and further comprising nanoparticles of materials selected from the group consisting of silica, metal oxides and metal compounds comprising at least one of tungsten, molybdenum and chromium, and combinations thereof,
wherein these materials are all colloidally suspended in a liquid comprising aqueous and/or organic solvents, said amounts being sufficient to produce a marking layer atop said substrate having improved properties including at least one of stronger bonds, better color properties, and finishes smooth enough not to retain bacteria.