Ransburg Electro-Coating Corp. v. Ionic Electrostatic Corp., 10347.

• Decision Date: 11 April 1968
• Docket Number: No. 10347.,10347.
• Citation: 395 F.2d 92
• Parties: RANSBURG ELECTRO-COATING CORP., Appellee, v. IONIC ELECTROSTATIC CORPORATION, Appellant.
• Court: U.S. Court of Appeals — Fourth Circuit

395 F.2d 92 (1968)

RANSBURG ELECTRO-COATING CORP., Appellee, v. IONIC ELECTROSTATIC CORPORATION, Appellant.

No. 10347.

United States Court of Appeals Fourth Circuit.

Argued May 5, 1966.

Decided April 11, 1968.

Edward F. Levy, New York City (John S. McDaniel, Jr., Lawrence A. Kaufman, and Cable & McDaniel, Baltimore, Md., on the brief) for appellant.

James P. Hume, Chicago, Ill., Howard W. Clement, Chicago, Ill., Verne A. Trask, Indianapolis, Ind., and Anderson, Coe & King, Baltimore, Md., on the brief for appellee.

Before HAYNSWORTH, Chief Judge, and BOREMAN and J. SPENCER BELL,^* Circuit Judges.

HAYNSWORTH, Chief Judge:

The defendant has appealed from an order holding it in contempt of an injunctive order entered in a patent case. The contempt finding is premised upon a finding that certain devices for use in electrostatic spray painting systems are the equivalent of certain other devices previously found to infringe the plaintiff's patents and that the sale and use of the new devices were proscribed by the terms of the injunction. In light of the prior art, which the patentee has no right to appropriate, we think the finding erroneous.

Plaintiff's patents cover paint feeding mechanisms in which paint is delivered to atomizing heads connected with one terminal of a high voltage source on the order of 90,000 volts, creating an electrostatic field between the head and the grounded objects to be painted. The electrostatic forces atomize the paint into small droplets, each highly charged with negative ions, and the electrostatic field deposits them on the work. The defendant's devices with which we are now concerned have insulated or nonconductive heads unconnected to any power source. Rotated at speeds up to 21,000 r.p.m., atomization of the paint is essentially centrifugal, but the head itself is within an electrostatic field created by a discharging electrode electrically connected to a high voltage source from which the uncharged head acquires a static charge equal to that of any other object within the electrostatic field along the same line of force. Whether the plaintiff's patent and the injunction against its infringement can reach the defendant's devices in which the atomizing head is not the discharging electrode is the essential question.

Some reference to the prior art is essential to an understanding of the problem.

Spray painting has long been known. Compressed air has long been used for breaking paint into fine droplets, known in the trade as "atomizing," on the same principle as employed in ladies' perfume bottles, insecticide spray cans and a multitude of household and industrial devices. Air spray guns are still used for a multitude of purposes, including very fine finishing, though airless guns have been developed with nozzles which achieve atomization of paint delivered under pressure for use in such finishing.¹

Outside of the fine furniture field, however, the use of air spray guns for most industrial painting was wasteful of material, particularly when the objects to be painted were a succession of objects moving along a production line. There were other obvious disadvantages, for there was not only a waste of paint, but a collection of unwanted paint on other objects within the range of the sprayer.

This led to the introduction of electrostatic fields by connecting a discharging electrode to one side of a high voltage source and connecting the other side to the work to be painted or to the ground, in which event the work to be painted was grounded. Paint atomized in an air spray or centrifugally when introduced into such an electrostatic field picked up static charges from the field, which tended to make particles repel each other while each was being attracted to the work. This system was referred to for convenience as "Ransburg No. 1," for the plaintiff has long been prominent in this area and holds a number of expired patents upon variants of the general prior art system.

For the uses for which we are now concerned, the Ransburg No. 1 system was a substantial improvement over the use of spray guns without the assistance of the electrostatic field. It greatly reduced the waste of paint and its deposition upon unwanted material, but it did not entirely eliminate it. Some particles of paint acquired such great velocities that the forces in the electrostatic field were of insufficient strength to control their movement.

Ransburg then developed its No. 2 system represented by the patents in suit.² Under this system paint is fed at a controlled rate to a stationary head or one revolving at a relatively low speed for the sole purpose of delivering the paint in a film to the edge of the rotating head. The head itself is directly connected to the negative terminal of a high voltage source, however, which makes the head the discharging electrode. There is thus created an electrostatic field between the head, as the discharging electrode, and the work which, with 90,000 volts, is itself effective to break up the paint into fine particles and move the particles through the electrostatic field and deposit them on the work. The field is quite comparable to an electromagnetic field, which we have all observed with the use of iron filings, and is quite effective to deposit paint on all sides of such objects as broom handles.

The Ransburg No. 2 system is quite effective in overcoming the disadvantages of the No. 1 system. Waste is completely eliminated, or almost completely so, and the particles of the paint are finer and much more uniform than in the previous system as practiced before Ransburg No. 2 was developed. This was because no other forces than the electrostatic field were acting upon the particles to give them velocity and because the initial negative charge of each particles was substantially the same as that delivered directly to the discharging head by the power source. Inventiveness was said to lie essentially in use of the head as the discharging electrode and in the concept of achieving atomization by electrostatic forces rather than by the mechanical forces theretofore employed.

With general success, Ransburg asserted its patents on the No. 2 system against copyists defending on the ground of patent invalidity because of obviousness and non-infringement because in the accused devices atomization of the paint was achieved by a combination of mechanical and electrostatic forces.³ These were the original questions in this action, for the defendant had marketed spray guns with a spray head connected directly to a high voltage source, but rotating at speeds in the order of 900 r.p.m. so that atomization of the paint was the product of mechanical, as well as electrostatic forces. The District Court found the patents valid, and applied to them the "broad," not the "narrow"⁴ construction to find infringement as long as the electrostatic forces played a substantial, though not an exclusive, part in the atomization of the paint.⁵ We affirmed on the opinion of the District Court,⁶ and that seems to be the consensus,⁷ for Ransburg's patents are entitled to a sufficiently broad construction that they may not be practiced by the introduction of contributory forces which do not remove dependence upon the electrostatic forces for the atomization of the paint. It was found to have been quite enough if atomization of the paint had been accomplished through the teachings of the patent, though other available means to that end were also employed.

Appropriately, an injunction was issued against further infringement by Ionic. Meanwhile, however, Ionic had brought out three new models in which there is no direct connection between the atomizing head and the power source and in which, it is contended, electrostatic forces play no part in the atomization of the paint.

Because of these new models, of...