Lewis E. Walkup v. Harold G. Greig

332 F.2d 800, 52 C.C.P.A. 701
CourtCourt of Customs and Patent Appeals
DecidedJune 11, 1964
DocketPatent Appeal 7053
StatusPublished
Cited by8 cases

This text of 332 F.2d 800 (Lewis E. Walkup v. Harold G. Greig) 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
Lewis E. Walkup v. Harold G. Greig, 332 F.2d 800, 52 C.C.P.A. 701 (ccpa 1964).

Opinions

WORLEY, Chief Judge.

Walkup, junior party in Interference No. 89,802, appeals from the decision of the Board of Patent Interferences awarding priority of invention of the eight counts therein to Greig, senior party. Walkup states here that he seeks reversal of the board’s decision as to counts 1 to 7, but not count 8. Accordingly the appeal is dismissed as to that count.

Greig is involved on the basis of his patent No. 2,811,465, having a filing date of April 30, 1952, and assigned to Radio Corporation of America, hereafter RCA. The counts correspond to claims of that patent copied in Walkup application Serial No. 401,811, filed January 4, 1954, and owned by the Xerox Corporation, [801]*801which was formerly the Haloid Company, hereafter Haloid.1

Greig took no testimony to prove conception and reduction to practice prior to his filing date and thus is restricted to that date. Walkup took testimony and relied on certain activities which took place between August 25 and September 5, 1950, as proving conception and actual reduction to practice.

The counts are directed to a device for use in the reproduction of visual images by the process of xerography. Testimony for Walkup shows that xerography involves the use of a base plate of conductive material coated with a thin layer of photoconductive material which is relatively insulating in darkness and relatively conductive when illuminated. The entire exposed area of the photo-conductive coating is first given a uniform electrical charge in the darkness, which charge remains as static electricity. Then a light image of the item to be reproduced is made to fall on the surface of the photoconductive layer with the result that the illuminated areas of the layer become relatively conductive and the charges on those areas pass through the layer to the underlying base plate and discharge to ground. The non-illuminated areas continue to be non-conductive, and the charges there remain in place on the surface of the photo-conductive layer. There is thus created on the photoconductive layer a pattern of electrostatic charges corresponding to the applied light image, which pattern is referred to in the counts as a “latent electrostatic charge image.”

The latent electrostatic charge image is developed by turning it into a material and visible image. To accomplish that, a finely-divided pigmented electroscopic powder of opposite polarity to the charges on the photoconductive surface is transported into the field of attraction of those charges. The particles, called toner, are attracted to and held on only the charged area of the plate. Subsequently, the toner image is transferred to another surface, as to paper. In another form of xerography, the toner is not applied to the plate bearing the latent image, but is applied directly to a paper web placed on the plate after its exposure, the toner being held on the paper by the electrostatic charges on the plate acting through the paper.

The counts relate to a development device for conveying toner particles into the field of attraction of the latent image to develop a material image from the latent image. In general, the device embodies a cylindrical member having a surface which is capable of retaining toner means received from supply means and is rotated into contact with the image bearing surface. The construction is brought out more specifically by counts 1 and 7 which are representative and read:

“1. A device for applying electroscopic developer material to a record receiving medium bearing a latent electrostatic charge image to be developed, said device comprising a cylindrical member presenting a peripheral surface capable of retaining a quantity of electroscopic material thereon, means for uniformly distributing a quantity of electroscopic developer material on said surface, and means for bringing said surface into contact with the surface of the record receiving medium.
“7. A device for applying electroscopic developer powder to a record receiving medium bearing a latent electrostatic charge image to be developed, said device comprising a cylindrical roller member having a surface provided with a multiplicity of small pits substantially uniformly distributed about said surface, means for applying a quantity of electroscopic developer powder to said roller, said powder being received and held by an electrostatic attractive force in said pits, and means for passing the record receiving medium into intimate rolling contact with said roller member [802]*802whereby to transfer, through electrostatic attraction greater than said first mentioned attractive force, portions of said developer powder from said roller onto selected areas of said record receiving member corresponding to said charge image.”

In 1950, Battelle Memorial Institute was conducting research on xerography under the sponsorship of Haloid. The work was carried on in the Graphic Arts Division of Battelle under the direction of one William T. Reid, and Walkup was Assistant Supervisor of that Division in charge of the work done on xerography.

Prior to August and September of 1950, Walkup had been active in work on a technique of xerographic development known as “cascade.” He describes cascade development as employing a mixture of small dust-like particles of toner, which it is desired to deposit in charged image areas, and larger bead or marble-like particles called “carrier,” which are predominately of spherical shape. The mixture tumbles or slides across a sloping image-bearing plate under the influence of gravity. The particles and toner have such properties, described as “tribo-electrical” relationship, that the toner particles will have a polarity causing them to detach themselves from the carrier particles in charged portions of the image-bearing articles and be attracted to the photoconductive surface.

For conception of the different type of development of the invention in issue, referred to as brush development, Walk-up relies on a June 14, 1950 entry in his laboratory notebook which reads:

“It has been known an [sic] used that a granular material can be used as a vehicle for developer powder both in the development and the cleaning of a xerographic plate. If a lot of developer powder is mixed with the larger granular material then the resulting mixture is rich in powder and if it is cascaded over a plate carrying an electrostatic image some of its powder will be given to the image and the image ‘developed’. If, on the other hand, there is little or no powder mixed with the granular material it will be poor or “lean” in powder. If the granular material is cascaded over the plate it will take powder off of the plate. This removal of the powder from the plate is used in cleaning the residual image off of the plate.
“The basically new idea suggested here consists in substituting fine fibers, as of a brush or fur, for the granular material. In this capacity, the fibers of the brush should work in a manner similar to action of the granular cleaner. Thus a soft brush should clean a plate, and a brush loaded with powder should ‘develop’ a plate. For either use the brush ox-fiber element may take a number of physical forms of which a cylinder with the fibers extending out approximately radially is typical and perhaps desirable. Departures from the radial direction may be desirable so that the fiber touches the plate as a line rather than as a point.
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Lewis E. Walkup v. Harold G. Greig
332 F.2d 800 (Customs and Patent Appeals, 1964)

Cite This Page — Counsel Stack

Bluebook (online)
332 F.2d 800, 52 C.C.P.A. 701, Counsel Stack Legal Research, https://law.counselstack.com/opinion/lewis-e-walkup-v-harold-g-greig-ccpa-1964.