US2327695A - Static eliminator in printing - Google Patents

Description

Patented Aug. 24, 1943 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to a static discharge device for use in discharging the static developed on paper when passing through a printing press.

It is old in the art to provide a high tension current which charges a number of discharge points that are preferably placed on an insulating bar that extends transversely across the paper as it runs through the press. These bars are made in a number of ways, but usually consist of a series of insulators mounted in a tube, each insulator supporting a short wire which extends toward the paper and acts as a discharge point. In order to energize the discharge points, a high tension element is introduced through the bar in such a manner that the electrons emitted from the element energize the discharge points, which constantly act to neutralize or discharge the static from the paper. When printing thin sheets or webs of paper, the static formed on the paper through the movement of one sheet over the other, is sufficient to cause considerable disruption of the sheets in the way they fall in the racks provided on the press; this interferes with the mechanical handling in connection with the printing.

A considerable amount of difficulty has been experienced in the type of high tension electrode which is used in the static eliminating bar, in that the electrode breaks down within a short time of use. These electrodes have here-to-fore been made from a conducting wire set within a rubber tube which acts as an insulating covering. The rubber deteriorates in a short time, and the high tension current begins to leak through, requiring an entire replacement of the rubber covered terminal.

I have found that a glass terminal, charged with the mercury vapor, or equivalent material, provides the same effect in the production of the required electrons, but does not deteriorate after long use.

In order that my invention may be more fully understood, reference is made to the accompanying drawing, in which:

Figure l is a diagrammatic elevation, showing the discharge bar with the discharge points projecting therefrom, and the electric transformer connections to energize the device.

Figure 2 is a partial sectional elevation showing the insulators cut away to expose the discharge points and the electrode for energizing the discharge bar.

Figure 3 is a section taken on the line 3-3 in Figure 1.

Figure 4 is a perspective view of the spacing block which separates the insulators.

Similar reference numerals refer to similar parts throughout the drawing.

In the drawing, l is a tube, preferably of metal. 2 is a support bracket attached to the ends of the tube, and adapted to be fitted to the frame of a printing press at such a position as to be under or over the sheet or web of paper as it passes through the press. 3 is a slot milled throughout the length of the tube, thereby forming two supporting edges 3A. 4 is an insulator, preferably porcelain, which is notched on each of its edges to conform to and engage the supporting edges 3A of the tube I, and in such a manner that the insulators will slide in the slot 3. The insulator 4 has a hole 5, adapted to receive a short piece of metal tubing 6, and from which projects substantially at ri ht angles a metal discharge wire I which extends through the insulator through a hole 8. In order to separate each of the insulators 4 with their discharge points 1 from the next insulator, a Wooden block spacer 9 is alternately inserted between the insulators. The spacer 9 is of sufiicient width to separate the tube 6, mounted in the insulator 4, from the succeeding tube 6. When the insulators, carrying their discharge points 1, and the spacers 9 are mounted in the slot 3 in the tube I, a high tension element If] is inserted through the bore of the tube 8. This high tension element is a glass tube in which there is sealed a conducting gas, such as mercury vapor. The high tension element It) is connected to the secondary H of a high tension transformer l2, which also has a primary l3 connected to an alternating current supply. The other end of the high tension secondary H is grounded preferably to the frame of the printing press.

In operation, the current is turned on the primary of the transformer, which induces a high tension current in the secondary coil II, which feeds to the high tension terminal which is preferably a mercury vapor tube It). This current induces a charge in the tube 6 mounted in the insulators 4, which is in turn carried to the discharge points 1. A sheet or web of paper [4, in passing through the press, has picked up a static charge from friction or by induction from other sheets or webs of paper, and moves over or under the discharge points I, whereupon the static charge on the paper is neutralized or discharged.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A static eliminator for printing operations,

consisting of a gas filled high tension tube, 'a plurality of conducting bands positioned around the said high tension tube and in capacity relation thereto, a conducting discharge point adjacent each of the said bands and. adapted to be placed in close proximity to a sheet or web of paper to be printed: I

2. A static eliminator for printing operations,

consisting of a source of high tension current, a gas filled tension tube, a plurality of conducting bands positioned around the said high tension tube and in capacity relation thereto, a conducting discharge point adjacent each of the said bands and adapted to be placed in close proximity to a sheet or web of paper to be printed.

THEODORE JOHN BEREGH.

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