Howard A. Fromson v. Anitec Printing Plates, Inc., and James R. Sullivan and Thomas P. Rorke

132 F.3d 1437
CourtCourt of Appeals for the Federal Circuit
DecidedFebruary 23, 1998
Docket96-1337
StatusPublished
Cited by17 cases

This text of 132 F.3d 1437 (Howard A. Fromson v. Anitec Printing Plates, Inc., and James R. Sullivan and Thomas P. Rorke) is published on Counsel Stack Legal Research, covering Court of Appeals for the Federal Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Howard A. Fromson v. Anitec Printing Plates, Inc., and James R. Sullivan and Thomas P. Rorke, 132 F.3d 1437 (Fed. Cir. 1998).

Opinions

Opinion for the court filed by Circuit Judge PAULINE NEWMAN, in which Chief Judge MAYER and Circuit Judge PLAGER join. Separate opinion, concurring, filed by Chief Judge MAYER.

PAULINE NEWMAN, Circuit Judge.

Howard A. Fromson appeals the decision of the United States District Court for the District of Massachusetts,1 ruling that the process for continuously anodizing aluminum used by Anitee .Printing Plates, Inc. did not infringe Fromson’s United States Patent No. Re. 29,754 (the ’754 patent). The court also ruled that the ’754 patent was invalid on the ground of obviousness. We affirm the holding of non-infringement, and reverse the holding of invalidity.

The Patented Invention

This invention relates to an improved process for continuously anodizing aluminum, whereby certain processing problems of electrical arcing and resistance heating are relieved, resulting in improved products and procedures accompanied by more rapid and efficient commercial production.

Metallic aluminum spontaneously oxidizes in air to form a thin coating of aluminum oxide upon its surface. This oxide coating protects the aluminum metal from further oxidation; however, the air-formed oxide is relatively soft, readily scratched and removed, and not of controllable durability and other properties that may be desired for specific uses. By the electrochemical process of anodization an aluminum oxide coating of controlled properties can be formed, by passing an electric current through a suitable oxygen-containing electrolyte, using the . aluminum metal as the positive electrode in the circuit. Since the positive electrode is the anode, the process is called anodization. The electrolytically formed aluminum oxide can be made to varying degrees of thickness, porosity, and hardness, selected for specific end uses of the anodized product. These properties are varied by adjusting the electrolytic, physical, and chemical conditions of the process in accordance with an extensive body of technical knowledge, experience, and skill.

[1440]*1440The Fromson ’754 patent is directed to a continuous anodization- process wherein aluminum sheet or wire or other shapes, called the aluminum web, is passed through a tank containing anodizing electrolyte. More rapid, continuous processing increases production and reduces costs, but the faster the speed at which the aluminum web is passed through the anodizing cells the higher the electric current must be in order to produce an oxide layer of the desired thickness. In turn, the use of high electric current densities may produce arcing when mechanical contacts are used to charge the moving aluminum web, or may produce burning when electrolytic contact cells are used.

High current densities also generate high heat at the interface where the aluminum enters the electrolyte. Due to the low resistance at the interface, surging of electrical current as well as burning of the aluminum surface and possible boiling of the electrolyte can occur as the hot metal enters the cells. Another problem in commercial anodization processes is that of resistance heating, wherein the aluminum heats up as it conducts the anodizing current. Due to any of these events, the product may be marred and unacceptable for use. This combination of long-standing problems had not been satisfactorily solved at the time of Fromson’s ’754 invention, despite much effort over many years.

In the prior art it was known to conduct anodization by passing the aluminum web through an initial cell called a contact cell, before it entered the anodization cell. By using a contact cell to electrolytically introduce the anodizing current into the web, surface damage done by mechanical electrical contacts, such as brushes and rollers, was eliminated. According to the ’754 invention certain problems of prior contact cell processes are ameliorated by directing the current flow so that the aluminum web is passed through an anodizing cell before it enters the contact cell, using two or more separate power sources. In the first cell an initial anodized oxide coating is produced; this coating protects the aluminum from surging current as it enters the contact cell and then a second anodizing cell. Anodizing current in the first cell is introduced by way of the cathodic contact cell, while a separate source of direct current connects the contact cell and the second anodizing cell. Additional cells and current sources may also be present. Thus the ’754 process uses two or more direct current power sources, the first flowing between the first cell and the contact cell, the second flowing in the opposite direction between the contact cell and the second cell. The process is illustrated in Figure 2 of the ’754 patent:

FIG. Z
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The claims in suit are 2, 11, and 13-15. Claim 2 is the broadest claim:

2. In a process for continuously electrolytically anodizing aluminum, the improvement which comprises introducing anodizing direct current from two or more sources in a cathodic contact cell having therein anodes connected to said sources of direct current, the aluminum having an anodized oxide coating formed thereon before entering said cell through the action [1441]*1441of the direct current introduced in the contact cell itself.

Claim 11 specifically recites that the anodizing current is divided so as to flow through separate cross-sections of the web:

11. In a process for continuously electrolytically anodizing a moving aluminum web using the cathodic contact cell technique, the improvement which comprises introducing anodizing direct current from at least two direct current sources into said moving aluminum web into at least two cross-sections thereof, portion of the anodizing being carried out before the aluminum web enters the contact cell.

Claims 13-15 describe the process in greater detail. Claim 13, which depends from claim 11, recites that the anodizing currents flowing in two cross-sections of the web flow in opposite directions. Claims 14 and 15 both state that a porous anodic oxide coating is formed on the aluminum before it enters the contact cell. Claim 14 is illustrative:

14. Process for continuously forming a porous anodic oxide coating on aluminum which comprises:
(i) passing aluminum through a cathodic contact cell, said aluminum having a portion of the thickness of said porous anodic oxide coating already formed thereon before entering said contact cell through the action of anodizing direct current from a first source of direct current introduced into said contact cell; arid
(ii) further' anodizing the already ario-dized aluminum to form the remaining portion of the thickness of the porous anodic oxide coating by introducing anodizing direct current from a second source of direct current into said already anodized aluminum in said contact cell.

I

INFRINGEMENT

The Anitec process, as illustrated in an Anitec document at trial, also uses three cells, like the illustrated Fromson embodiment, plus a rinse step:

Anodizing Section
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132 F.3d 1437, Counsel Stack Legal Research, https://law.counselstack.com/opinion/howard-a-fromson-v-anitec-printing-plates-inc-and-james-r-sullivan-cafc-1998.