Method and apparatus for testing the wrappers of cigarettes and the like

Abstract

A first signal is generated indicative of the gas permeability of the wrapper of the article being tested. A second signal is generated indicative of the porosity of the material of the wrappers of the articles being tested. The first and second signals are processed to form for each article a third signal indicative, to an extent greater than the respective first signal, of the component of the gas permeability of the article not attributable to the porosity of the material of the wrapper. The third signal is compared to a reference signal to determine whether the wrapper of the tested article is defective. The aforementioned second signal is generated by averaging out the gas permeabilities of the wrappers of a number of such articles. In order to generate a second signal not influenced by the marked gas permeability variations encountered when testing defective cigarettes, the gas permeabilities of the wrappers of defective cigarettes are positively excluded from the averaging out involved in the generation of the aforementioned second signal.

Dependencies are inferred from the claim text.