Application of Kenneth A. Metcalfe and William H. Lowe

410 F.2d 1378, 56 C.C.P.A. 1191
CourtCourt of Customs and Patent Appeals
DecidedJune 5, 1969
DocketPatent Appeal 8158
StatusPublished
Cited by8 cases

This text of 410 F.2d 1378 (Application of Kenneth A. Metcalfe and William H. Lowe) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Application of Kenneth A. Metcalfe and William H. Lowe, 410 F.2d 1378, 56 C.C.P.A. 1191 (ccpa 1969).

Opinion

RICH, Acting Chief Judge.

This appeal is from a decision of the Patent Office Board of Appeals affirm *1379 ing the rejection of claims 10-14 of application serial No. 293,853, filed July 9, 1963, entitled “Liquid Developer for Electrostatic Images.”

The Invention and Claims

The invention relates to a liquid developer for use in electrostatic printing processes. Broadly, such processes involve the creation of latent electrostatic images on a suitable substrate, such as paper, followed by “development” of the images by the application of pigment particles to render them visible. The particles, which have an electrical charge of their own, satisfy the charge of the electrostatic image and, being thereby deposited on the latter, render it visible. In liquid development of electrostatic images, the pigment particles are suspended in a liquid carrier which usually has high electrical resistivity to prevent the electrostatic image from leaking away prior to full development.

Appellants have discovered that the shelf life or “keeping qualities” of such liquid developers can be improved by dissolving therein a resin having a relatively small attraction with respect to the pigment particles so that only about 2% of the resin adheres to the particles. It appears that electrical charges are formed in the resin-containing liquid carrier and on the resin-coated pigment particles as a consequence of what appellants refer to as the “well known theory that a resin immersed in a liquid carrier will possess an electrical charge.” Since like charges repel each other, the resin acts as a dispersing agent in that the thinly coated pigment particles are forced apart. According to appellants, the particles remain in suspension for long periods without settling or clumping together, thereby avoiding sedimentation during storage.

Claim 10 is representative (emphasis added):

10. An improved liquid developer consisting essentially of pigment particles and a carrier liquid, said pigment particles being suspended in said carrier liquid, said liquid having relatively high electrical insulating properties, and a resin in said carrier liquid and having an oil length of not less than about 60% and being substantially fully polymerized, the pigment particles having a diameter of not greater than one micron and being insoluble in the carrier liquid, the resin being soluble in the carrier liquid, there being approximately six parts of resin to one part of pigment by weight, the said resin being a wetting agent for the pigment particles and being such that only about two percent of the said resin in relation to the weight of the pigment is held to the pigment, whereby the pigment particles are forced apart to deposit independently when subjected to an electrostatic field.

All the claims are rejected on three grounds: (1) Obviousness—35 U.S.C. § 103, (2) Insufficiency of Disclosure—35 U.S.C. § 112, and (3) Undue Breadth of Claims—35 U.S.C. § 112.

Obviousness

In support of the obviousness rejection the Patent Office relies on two United States patents:

Metcalfe 3,032,432 May 1, 1962

Mayer 2,891,911 June 28, 1959

Metcalfe discloses a liquid developer composition for developing electrostatic images containing a pigment, a high-resistivity carrier liquid, and a resin which functions as a “combined control and fixing agent.” It appears that the resin is the Metcalfe developer improves tone control during development by decreasing the electrical resistivity of the liquid carrier, thereby effecting a limited bleeding away of the electrostatic image.

The only specific resins mentioned in Metcalfe are “Rhodene L6/100 (a linseed oil modified alkyd resin of medium oil length)” and “Pentarol 20 (a phenol modified pentaerythritolester of [sic] resin).” In the only specific developer disclosed in Metcalfe these two resins are employed in equal amounts which provide a resin: pigment ratio of 1:5. Mayer *1380 is relied on “only for its disclosure of a pigment particle size below one micron.”

Sustaining the rejection of all claims as “unpatentable over Metcalfe * * * in view of Mayer et al., under 35 U.S.C. 103,” the board said:

Since the medium oil length resin in Metcalfe et al. apparently would be at least near 60% in length, and is dissolved in the same carrier liquid used by appellants, the only material distinction that we see in claim 10 over the references is the ratio of 6 parts resin per part pigment. The functional properties recited in the claims appear to be true of Metcalfe et al., at least to a material degree. * * * We see no reason why the ratio of 6 parts of resin to one part of pigment should be critical, especially as appellants’ Example 3 uses a ratio of 2.4:1. Adjustment of proportions is usually a routine matter, the optimum values depending upon the specific result desired.

We will not affirm this rejection because we are convinced that “the only material distinction” referred to by the board contributes quite materially to the un-obviousness of appellants’ invention “as a whole” (35 U.S.C. § 103), and because we See nothing in either of the cited references which would lead one of ordinary skill in the art to use, for any reason, thirty times the amount of the resins used by Metcalfe (6:1 claimed by appellants vs. 1:5 in Metcalfe) or to expect that carrier-soluble resins could be used as dispersing agents in such developers.

Sufficiency of Disclosure

Appellants have broadly disclosed that the resin used in the composition of their invention must be soluble in the carrier employed to an extent which makes it possible to have a resin :pigment ratio of about 6:1. It is also disclosed that the resin must be chosen so that only about 2% thereof adheres to the pigment. In addition, appellants’ specification contains three examples in which specific resins are shown to work with specific pigments and liquid carriers. In these examples, however, the resins employed are identified only by type, trademark, and manufacturer. Thus, the resins are identified in Example 1 as “a long oil linseed oil modified alkyd resin known under the trade mark PC2/70 of the Polymer Corp. Pty. Ltd., Sydney, oil length 72%”; in Example 2 as “ ‘Paralae 10’ * * * the trade mark of Imperial Chemical Industries for a long oil linseed oil modified alkyd resin”; and in Example 3 as “ ‘Super Beckosol 1352’ resin (an isophthalic long oil alkyd by Reichold Chemical Ind.

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410 F.2d 1378, 56 C.C.P.A. 1191, Counsel Stack Legal Research, https://law.counselstack.com/opinion/application-of-kenneth-a-metcalfe-and-william-h-lowe-ccpa-1969.