Everseal Stationery Products Ltd v Document Management Solutions Ltd & Others  EWHC 842 (IPEC) is a decision of Judge Hacon in the Intellectual Property Enterprise Court, England and Wales, dating back to the beginning of this month.
Everseal had a patent for a product which still has some currency, even in the age of the internet: this product was a "mailer", this being a business communication which was folded, sealed by an adhesive around its periphery and sent through the terrestrial post. Claim 1 of Everseal's patent disclosed a mailer including an adhesive which self-sealed irreversibly under "finger pressure" namely pressure of 500 kPa or less. Claim 7 disclosed a mailer in which the adhesive was a natural rubber latex adhesive stabilised with ammonia.
DMS developed mailers which were referred to in the judgment as Mailer 1, Mailer 2 and Mailer 3. Everseal sued DMS for infringement of its patent; DMS counterclaimed for invalidity. The court had to decide whether (i) DMS's mailers fell within claims 1 and 7, and in particular whether DMS's adhesives sealed "irreversibly" and (ii) whether the patent was invalid for lack of novelty or inventive step over three pieces of prior art (Viking mailer, Faltin, and Johnsen).
Judge Hacon held for DMS. In his view:
* an adhesive self-sealed "irreversibly" if the recipient, receiving the mailer, could tell from both the adhesive structure and the appearance of the base material that it had previously been opened. If the fact that it had previously been opened was not betrayed by each of those criteria taken separately, the adhesive did not self-seal irreversibly when the mailer was first closed.
* it could be assumed that anyone who had previously opened the mailer without permission would have taken some limited effort to hide the fact that he had done so.
* the seals on Mailer 1 were irreversible within that meaning; mailer 1 infringed claim 1 of the patent.
* infringement of claim 7 would have required Everseal to show that the adhesive used for Mailer 1 was a natural rubber adhesive stabilised with ammonia, but there was no evidence to that effect.
* experiments carried out by DMS did not enable the court to reach any conclusion as to whether opening Mailers 2 or 3 resulted in the disruption in the mailer's base material so as to demonstrate that their adhesives sealed irreversibly, and Everseal had chosen not to conduct its own experiments.
* the burden rested on Everseal to prove infringement, but it had not done so regarding Mailers 2 and 3.
* turning now to the counterclaim, claim 1 of the patent lacked novelty over the Viking mailer which had an irreversible seal and had self-sealed under finger pressure. Claim 7 did not however lack novelty over the Viking mailer.
* where lack of novelty turned on whether an alleged prior use had particular features, it was sufficient to adduce evidence which proved, on the balance of probabilities, facts establishing that the prior use had those features. In contrast, where the court was invited to infer that prior use had one or more features on the basis of primary facts proved, the invention would lack novelty only if the inference was inevitable. Here the evidence -- that it was likely that the adhesive in the Viking mailer was a natural rubber latex stabilised with ammonia -- was not enough to establish lack of novelty regarding claim 7.
* the patent did not lack novelty over Faltin or Johnsen, since neither of them explicitly disclosed an irreversible seal.
* Claim 1 did however lack inventive step over Faltin and Johnsen, and over the Viking mailer if it did not anticipate the invention. Everseal had suggested no technical prejudice which would have deterred a skilled team, working prior to the claimed invention, from using an adhesive which self-sealed under finger pressure to create an irreversible seal.
* Claim 7 also lacked inventive step, the evidence being that a skilled person would have been expected to find a suitable formulation without difficulty.
This is a curious case, in that the litigation over this patent was commenced in the Patents County Court (PCC) in February 2010, before that court's rules were radically overhauled with effect from 1 October. The PCC then gave separate rulings on two preliminary points; the ownership of the patent was disputed; there were also a Tomlin Order, allegations of unlawful threats and two separate applications to amend the patent before the infringement action was finally heard by the IPEC. One might be tempted to wonder whether the sequential segmenting of issues is always more efficient than trying to hear as many things as possible all in one go.