This appeal is from the decision of the Patent Office Board of Appeals which affirmed the rejection of claims 126 to 162 in appellants' application serial No. 662,319, filed May 29, 1957, entitled "Photographic Reproduction." Thirty-one claims stand allowed.

The invention relates to electrophotography, in particular to chemical compounds which are photoconductive and thus useful as coatings for substrata on which it is desired to reproduce images. The compounds are 2,5-bis (para-aminophenyl)-1,3,4-oxadiazoles.

In electrophotography, a substratum (e. g., paper, glass, metal foil, etc.) is coated with a photoconductive substance (i. e., a substance whose electrical conductivity is dependent upon the amount of light to which it is subjected) to provide a surface upon which images are reproducible. The photoconductive layer, although not light-sensitive per se, is rendered so by applying to the coated article an electrostatic charge (e. g., by corona discharge1). Images to be reproduced are placed atop the charged surface which is exposed to illumination by conventional photographic methods, whereby the coating locally dissipates its charge in proportion to the intensity of illumination. Non-illuminated areas, which retain their charge, are then treated with electroscopic powder (e. g., colored synthetic resins) resulting in a visible image which may be transferred to another surface or may be fixed (e. g., by fusing), rendering the powder permanently adherent to the coated substratum.

The rejected claims define electrophotographic articles as well as a method of making them.2 Claims 129, 130, 131 and 157 are representative (emphasis ours):

"129. An electrophotographic material comprising an electrically conductive support layer and a photoconductive insulating layer, the latter containing a compound having the formula

NOTE: OPINION CONTAINING TABLE OR OTHER DATA THAT IS NOT VIEWABLE in which R, R₁, R₂, and R₃ are selected from the group consisting of hydrogen, alkyl, cycloalkyl, and acyl radicals; and X and X₁ are selected from the group consisting of hydrogen and halogen.

"130. An electrophotographic material according to claim 129 in which the photoconductive layer contains a dyestuff sensitizer.

"131. An electrophotographic material according to claim 129 in which the photoconductive layer contains an organic colloid.

"157. A method of making an electrophotographic material which comprises coating an electrically conductive support layer with a photoconductive insulating layer comprising a 2,5-bis-(p-aminophenyl)-1,3,4-oxadiazole."

The other rejected claims differ from the above claims in defining the oxadiazole compound with varying degrees of specificity. In article claims 141 to 156, specific oxadiazoles are recited. "Dyestuff sensitizers" according to appellants' specification are used to extend the sensitivity of the photoconductive layer "into the visible part of the spectrum * * *." Appellants disclose a host of dyes as applicable including triarylmethanes, xanthenes, thiazines, etc. "Organic colloids" are said to be "advantageous in preparing the photoconductive insulating layers" and may be natural and synthetic resins, synthetic polymers and the like. For what purpose they are "advantageous" is not expressly disclosed, but apparently they provide a fusible medium for fixation of the photoconductive layer after exposure.

The sole ground of rejection is unpatentability over the following reference:

In the Siegrist et al. patent, entitled "New Ox-Diazole Compounds and Process for their Manufacture," the patentees teach various oxadiazoles, the sole statement of utility of which is "for making organic material impenetrable to ultraviolet rays, for the optic brightening of organic material or as an intermediate product for the preparation of dyestuffs." (Emphasis ours.) Such compounds also "exhibit in solution or when applied to a substratum a green-blue to violet fluorescence in daylight or ultra-violet light." (Emphasis ours.) Appellants assert, and the Patent Office concedes, there is no teaching in Siegrist et al. that any oxadiazoles possess photoconductive properties. Appellants concede that some of the oxidiazoles of their claims are disclosed by Siegrist et al.

We shall discuss separately the rejection of the article claims and method claims.

The Patent Office position is that the reference teaches, or at least suggests, a "backing member" upon which is coated an oxadiazole as ultraviolet brightener; that such "backing member" may be paper which is "organic material"; and that such coated paper would inherently be an article defined by appellants' claims. Stated another way, the Patent Office position is that appellants' claims define an article not distinguishable from a coated paper suggested by Siegrist et al.

"It is the Examiner's position that the instant claims recite no new or unobvious article even though the intended use may be different.

"Siegrist et al clearly discloses coating the composition on a `backing member', which is substantially all the structure that is required * * * [by appellants'] claims * * * to be `an electrophotographic material'. * * *

"The requirement in the instant claims that the backing member be `electrically conductive' is not seen to define any significant structural distinction since any material is `electrically conductive', even the best insulators known. In any event, note that applicants may employ such backing materials as glass or paper * * *. The obvious and well known use for ultra-violet absorbers and optic brighteners, the utility suggested by the reference * * * is in paints, inks, photographs, and coating compositions in general, for example in the optical brightening of paper. Nor is it deemed unobvious to broadly classify substrates into two distinct categories, i. e. conductive and non-conductive, where there is no apparent reason to limit the reference to non-conductive substrates."

"Appellants rely upon the preamble directed to `An electrophotographic material' to support patentability of [the] article claims * *.

"We do not agree with appellants' interpretation of the preamble which, in our opinion, neither requires specific structure nor suggests a particular function. The term `An electrophotographic material' does not indicate what structure other than that specified in the terms of the claims is required nor how said material is to be employed in an electrophotographic process. Thus, the preample differs from those considered by the court in the decisions cited in appellants' brief and in particular, from the printing plate to which the claims in In re Schmidt, 48 CCPA 1140; 772 O.G. 897; 293 F.(2d) 274; 130 U.S.P.Q. (BNA) 404 were directed. * * *

"We further disagree with appellants in that we must look to appellants' specification to determine what is intended by the claimed element, `an electrically conductive support layer', since this term is not of itself clearly definitive. As pointed out by the Examiner, appellants' description includes as apparent representatives of this element, a glass plate * * * or paper sheets or webs * * *. We note the paper sheets or glass plates are not stated to be further treated to make them additionally electro-conductive and in fact, the paper sheets are treated with coatings which would be expected to tend to decrease electrical conductivity. Thus, we agree with the Examiner, in view of the disclosed representative examples of the otherwise undefined electrically conductive support layer, that the substrates to which reference is made in Siegrist et al., or which are suggested therein, must inherently fall within the terms of the claims.

* * * * *

"Merely referring to a possible use for such an article, not specified in the reference, does not render the composite patentable. We consider the situation before us to be somewhat analogous to that in In re Rosicky, 47 CCPA 861; 755 O.G. 929; 276 F.(2d) 656; 125 U.S.P.Q. (BNA) 341, since we hold the teaching of the utility of the oxadiazoles in Siegrist et al. to suggest to the chemist the use thereof as applied to substrates including paper, fabrics, and other material falling within the terms of appellants' claims."

Appellants argue that the preamble of their claims, when considered in conjunction with the other claim limitations, distinguishes their invention structurally over Siegrist et al.; that "There is no disclosure in Siegrist et al. of a photoconductive insulating layer or an electrically conductive support layer" and that accordingly "these structural recitations of the claims are not met"; that the claims are "definitive of an article of manufacture" not taught by the reference; and that the preamble does not constitute a mere "use" limitation.

We agree with the Patent Office that Siegrist et al. fairly teach paper coated with oxadiazole as optical brightener. The issue then is simply whether appellants' claims, read in the light of the disclosure distinguish the "electrophotographic material" over such coated paper.

As to the claim preamble, this court has frequently considered problems related thereto. See, e. g., Kropa v. Robie et al., 187 F.2d 150, 38 CCPA 858, and cases cited therein. We know no general rule for deciding the weight to be given preamples as positive structural limitations. Ellis,3 for example, states "Preambles are used primarily to give the field within which the invention has utility. They designate use rather than structure, form or composition." (Emphasis ours.)

In the instant case, we do not consider it to be controlling that the reference does not in haec verba disclose "electrophotographic material." The claims as a whole must be analyzed in light of the disclosure to see if the article defined thereby is distinguishable in fact, vis-à-vis in verbis, over the prior art.4

We first consider the limitation "electrically conductive support layer." As did the board, we look to the specification to see what appellants' claims mean. It says the support "may be of any material suitable for use in electrophotographic processes, for example, aluminum or other metal plates or foils; glass plates; paper sheets or webs, or plastic foil * * *." (Emphasis ours.) The paper may be pretreated against penetration in a conventional manner by coating with methyl cellulose, polyvinyl alcohol or the like. In twenty examples, sixteen employ paper as the support layer, defined simply as "paper foil," "transparent paper" or "translucent paper." Appellants, in neither the disclosure nor their brief, indicate that such paper is of any special type, other than being "suitable for use in electrophotographic processes."5 Accordingly, we are not convinced that a typical paper substrate suggested for use by Siegrist et al. is not "electrically conductive" as contemplated by appellants.

Appellants' "photoconductive insulating layer" may be an oxadiazole per se or mixtures thereof, or may be oxadiazoles in admixture with dyestuff sensitizers or organic colloids, discussed supra. As to coatings of oxadiazole per se, upon which we believe the phrase "photoconductive insulating layer" reads, nothing in the record indicates such a layer to be unlike oxadiazole coatings for ultraviolet reflecting. Merely calling the coating a "photoconductive insulating layer" does not make it any the less an admittedly old oxadiazole. Thus we hold that claims reciting an "electrically conductive support layer" and a "photoconductive insulating layer * * * containing * * [oxadiazole]" do not therein distinguish over Siegrist et al.

However, we do not agree with the board that claims which require that "dyestuff sensitizer" or "organic colloid" be present in the photoconductive layer do not distinguish over Siegrist et al.6 Nothing in the reference suggests dyestuff sensitizers or organic colloids in admixture with oxadiazoles, such admixture then used as a coating. A claim to such a combination of coating and support layer defines an article structurally different from any taught by Siegrist et al.

Thus, we hold the claims reciting that the "photoconductive insulating layer" contains oxadiazole do not distinguish over Siegrist et al. while the claims which recite "dyestuff sensitizer" and "organic colloid" as part of the "photoconductive insulating layer" do so distinguish.

Method claims 157 to 162 recite simply "coating" a support layer with photoconductive insulating layer. The examiner stated:

"Claims 157 to 162 do not distinguish over the references [sic] in that they merely recite the obvious method for preparing the article, i. e. by `coating'."

"Process claims 157 to 162 are directed to a single-step method which comprises `coating'. As pointed out in appellants' specification * * * the coating is applied `in known manner'. Hence the claimed step functionally defined in terms of its result cannot differentiate over the application to a substratum taught in Siegrist et al. and is apparently obvious to one having ordinary skill in this art."

Appellants urge in their brief "that while it may be obvious to prepare the article by coating once the article is known, it certainly can not be obvious to prepare the article by such a process when the article is unknown and, absent appellants' disclosure, there is nothing to teach the claimed article."

We agree with the board. Appellants' coating process appears to be conventional and therefore obvious. The fact that the final product is novel is not controlling of obviousness of the method. In re Larsen, 292 F.2d 531, 49 CCPA 711.

For reasons above stated, the decision of the board is affirmed as to claims 126, 129, 132, 135, 138 and 141 to 162; and is reversed as to claims 127, 128, 130, 131, 133, 134, 136, 137, 139 and 140.

Modified.