US3664298A

US3664298A - Manifold for fountain-type liquid dispenser

Info

Publication number: US3664298A
Application number: US22911A
Authority: US
Inventors: Edward Charles Giaimo Jr
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1970-03-26
Filing date: 1970-03-26
Publication date: 1972-05-23
Anticipated expiration: 1989-05-23
Also published as: SE363174B; GB1295027A; CH536663A; BE764784A; DE2114756A1; FR2078897A5; CA928489A; NL7104028A

Abstract

In an electrostatic printing machine, a manifold for applying liquid developer to an adjacent recording element comprises an elongated body of electrically conductive material. An exit slit, formed in the top surface, serves to direct the liquid developer to the recording element. A plurality of spaced-apart ridges extend upwardly from the top surface, adjacent side edges thereof, and form a plurality of spaced-apart slots between adjacent ridges, respectively, so that liquid developer that is pumped through the exit slit can flow off the top surface via the slots, in a direction perpendicular to the exit slit.

Description

United States Patent Giaimo, Jr.

[54] MANIFOLD FOR FOUNTAIN-TYPE LIQUID DISPENSER [72] Inventor: Edward Charles Glalmo, Jr., Princeton,

[73] Assignee: RCA Corporation [22] Filed: Mar. 26, 1970 [21] Appl. No.: 22,911

[52] US. Cl. ..l18/637, l18/DIG. 23, 118/429 [51] Int. Cl. ..G03g 13/00, [58] Field of Search ..1 18/637, 637 LX, DIG. 23, 612, 118/300, 410, 429, 400; 117/175, 37 LX, 222/579; 355/10; 228/36, 37

[56] References Clted UNITED STATES PATENTS 3,407,786 10/1968 Beyer'et a1 ..1 18/637 3,342,164 9/1967 Lewis ..118/637 3,507,252 4/1970 Leedom ..118/637 2,956,494 10/1960 Tyler et a1; 1 18/637 LX 1 May 23, 1972 3,303,983 2/ 1967 Patrick et al ..228/37 3,119,363 l/l964 Rieben ..ll3/l26 3,081,535 3/1963 Lincoln. ..228/37 3,536,243 10/1970 Higgins" ...228/37 3,482,755 12/1969 Racciti ..228/37 Primary Examiner-Morris Kaplan Assistant Examiner-Leo Millstein Attomey-Glenn H. Bruestle [57] ABSTRACT ln an electrostatic printing machine, a manifold for applying liquid developer to an adjacent recording element comprises an elongated body of electrically conductive material. An exit slit, formed in the top surface, serves to direct the liquid developer to the recording element. A plurality of spacedapart ridges extend upwardly from the top surface, adjacent side edges thereof, and form a plurality of spaced-apart slots I between adjacent ridges, respectively, so that liquid developer that is pumped through the exit slit can flow off the top surface via the slots, in a direction perpendicular to the exit slit.

8 Clalns, 5 Drawing Figures PATENTEDHAY 23 I972 SHEET 1 0F 2 MJW MANIFOLD FOR FOUNTAIN-TYPE LIQUID DISPENSER BACKGROUND OF THE INVENTION This invention relates generally to an improved manifold, and more particularly to an improved manifold for applying a liquid to a horizontal surface. The improved manifold is particularly useful in an electrostatic printing system for applying electroscopic liquid developer to the surface of a moving electrophotographic recording element to develop an electrostatic charge pattern thereon.

The manifold of the present invention is an improved structure for use with a fountain-type liquid dispenser of the type described in US. Pat. application, Ser. No. 640,564, filed May 23, 1967, for M. A. Leedom, and entitled Combination of a Container for a Liquid and Means for Dispensing the Liquid, now US. Pat. No. 3,507,252, issued on Apr. 21, 1970." In the prior-art liquid dispenser, an exit slit for a manifold is formed between two parallel and horizontal strips of metal, each strip having parallel sides and both strips functioning as a bias electrode when connected to a source of voltage. While the priorart manifold is suitable for certain applications, it has been found that when liquid developer, comprising toner particles dispersed in a carrier liquid, is pumped through the exit slit, the liquid developer does not always flow freely and directly from the exit slit to the nearest side edges of the bias electrode. This is believed to result from the interaction between the surface tension of the liquid developer and the nonuniform wetting of the bias electrode. Consequently, the liquid developer sometimes spills over the edges of the bias electrode only at random points along its length, causing transverse eddy currents to form in the liquid developer. This action tends to concentrate the toner particles of the liquid developer at those points along the edges of the bias electrode where the liquid developer spills over. Such action may result in an uneven application of the liquid developer to a recording element to be developed, causing uneven development and I SUMMARY OF THE INVENTION The improved manifold for applying a liquid to a surface comprises a body that has a surface with an exit slit formed in a portion thereof. Means are disposed along each side of the exit slit to cause liquid dispensed from the exit slit to flow laterally therefrom to, and over, opposite edges of the top surface at a multiplicity of points thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional drawing, partly schematic, of a combination of a container for a liquid and means for dispensing the liquid, showing a cross-section of the improved manifold, taken along the line 11 in FIG. 2, for applying the liquid to a moving electrophotographic recording element;

FIG. 2 is an enlarged, perspective view of the improved manifold shown in FIG. 1;

FIG. 3 is an enlarged, perspective view of another embodiment of the improved manifold;

FIG. 4 is a fragmentary, enlarged, perspective view of still another embodiment of the improved manifold; and

FIG. 5 is an enlarged perspective view of a further embodiment of the improved manifold.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, there is shown an electrophotographic recording system 10 for electrostatically charging, exposing, and developing an electrophotographic recording element 12 with the aid of a fountain-type liquid dispenser 14 for an electroscopic liquid developer 16. With the exception of an improved manifold 20 for the fountain-type liquid dispenser 14, the operation of the electrophotographic recording system 10 is described in detail in the aforementioned US. Pat. application, Ser. No. 640,5 64.

Briefly, the recording element 12, comprising a substrate 22 of paper and a photoconductive layer 24 thereon, is electro statically charged in darkness by double corona discharge devices 26 and 28 connected to a suitable source of unidirectional voltage. The electrostatically charged photoconductive layer 24 is exposed by an image on the face of a cathode-ray tube 30, the cathode-ray tube 30 being connected to a suitable signal source 32, such as a character generator well known in the art. The recording element 12 with an electrostatic latent image thereon, resulting from the exposure of the charged photoconductive layer 24, is moved in the directions of the

arrows

34 and 36 by any suitable means, adjacent to the manifold 20 where it is developed by the electroscopic liquid developer 16. The developed image which may be dried by any suitable means known in the art represents a reproduction of the exposure image provided by the cathode-ray tube 30.

The operation of the fountain-type liquid dispenser 14, with the exception of the improved manifold 20, is also fully explained in the aforementioned US. Pat. application, Ser. No. 640,564. Briefly, the liquid developer 16, in a reservoir 38, is pumped by a pump 40 through suitable conduits to a standpipe 42 and to the manifold 20, in directions indicated by arrows representing liquid developer flow. The liquid developer 16 is returned from both the standpipe 42 and the manifold 20 through suitably placed return conduits, as indicated by the arrows showing the directions of flow of the liquid developer 16. The standpipe 42 communicates with the manifold 20 and serves to provide a constant pressure to the liquid developer 16 emerging from the manifold 20.

The improved manifold 20, shown in FIGS. 1 and 2, comprises an elongated body which may be either a solid metal, such as stainless steel, for example, or a body 44 of plastic material covered with a cover 46 of metal, such as stainless steel. The improved manifold 20 is secured to the top surface 47 of the fountain-type liquid dispenser 14, as at 49, by any suitable adhesive or fastening means. The cover 46 of the improved manifold 20 comprises electrically conductive material because it functions as a bias electrode, the cover 46 being connected to the negative terminal of a variable voltage source 48 by a conductor 50. An electrically conductive roller 52, for disposing a horizontal surface of the recording element 12 adjacent to the manifold 20 for development, is connected to the positive terminal of the voltage source 48 through a conductor 54. The polarity of these connections depends on the charge on the recording element 12, the polarity of the toner particles in the liquid developer 16, and whether direct orreversal prints are desired. The conductor 50 is attached to the cover 46 by any suitable means, as, for example, solder.

The manifold 20 comprises a planar top surface 56 formed with an elongated exit slit 58 in a portion adapted to be disposed in a horizontal position. The exit slit 58 extends in a direction intermediate opposite ends 60 and 62 of the manifold 20 and is substantially parallel to opposite sides 64 and 66 of the manifold 20. The exit slit 58 extends through the top surface 56 and serves to communicate with the conduits of the fountain-type liquid dispenser 14 leading from the pump 40 to direct the liquid developer 16 onto the photoconductive surface 24 of the recording element 12. The portion of the top surface 56 in which the exit slit 58 is formed is adapted to be positioned in a horizontal plane so that it may direct the liquid developer 16 onto a horizontal portion of the recording element 12 that is disposed adjacent to, and slightly spaced from, the exit slit 58 by the roller 52.

Means are provided to cause the liquid developer 16 that emerges through the exit slit 58 to flow evenly over the surface 56 and to spill over opposite edges 68 and 70, formed by the top surface 56 and the opposite sides 64 and 66, respectively. To this end, a plurality of regularly spaced-apart fingers 72, extending laterally from a strip 74, are adhered to the opposite sides 64 and 66 by any suitable means, such as screws 73 and 75, to provide a plurality of regularly spaced-apart ridges 76 extending upwardly from the top surface 56 along the opposite edges 68 and 70. The upper portions of the fingers 72 are bent inwardly toward the exit slit 58 to provide the ridges 76. Regularly spaced-apart slots 78, formed by adjacent ridges 76, provide regularly spaced channels through which the liquid developer 16 that emerges through the exit slit 58 can spill over. Thus, by providing the plurality of regularly spaced slots 78, means are provided for the liquid developer 16 to spill over at a plurality of regularly spaced points along the opposite edges 68 and 70, whereby to provide a substantially even flow of liquid developer 16 over the top surface 56 in a direction substantially perpendicular to the length of the exit slit 58.

The width of each finger 72 may be in the range between 0.020 and 0.060 inch and the width of the slots between adjacent ridges 76 may be in the range between 0.010 and 0.030 inch. The thickness of the fingers 72 may be in the range between 0,005 and 0.015 inch and, hence, each extends a distance in the range between 0.005 and 0.015 inch above the top surface 56 of the manifold 20. This structure has the advantage of causing a head of liquid, larger than would otherwise be possible, to form on the top surface 56 for developing the recording element 12. The width of the manifold 20 is about one-half inch and its length about 6 inches. These measurements, however, are merely illustrative of one embodiment of the improved manifold 20 and are not to be considered in a limiting sense.

Referring now to FIG. 3, there is shown a manifold structure 80, another embodiment of the improved manifold 20. The manifold structure 80 comprises an elongated body 82 either entirely of an electrically conducting material or of a plastic material covered with a cover of electrically conducting material and secure to the top surface 47 of the fountain-type liquid dispenser 14. The manifold structure 80 is formed with an elongated exit slit 84 in a portion of a top concave surface 85 adapted to be disposed in a horizontal position, and extends in a direction intermediate ends 86 and 88 of the body 82. The exit slit 84 communicates with the pump 40 in the manner described for the manifold 20. A plurality of regularly spaced slots 90 are formed along the opposite side edges 92 and 94 of the concave surface 85 on opposite sides of the exit slit 84. The conductor 50 is connected to the end 86 of the body 82 by a screw 95.

The radius of curvature of the top concave surface 85, which functions as a reservoir, is slightly greater than the radius of curvature of the cylindrical surface of the roller 52. Since a typical recording element may have a thickness of about 3 mils, and the roller 52 may have a radius of curvature of about one-halfinch, the radius of curvature of the top concave surface 85 should be about 0.050 inch greater than the radius of curvature of the roller 52, the top concave surface 85 being spaced a distance of about 0.050 inch from the roller 52. The slots 90 have a width in the range between 0.010 and 0.030 inch, and ridges 96, extending between the slots 90, have a width in the range between 0.020 and 0.060 inch. The foregoing dimensions are merely illustrative and are not to be construed in a limiting sense. The ridges 96 extend upwardly from the portion of the top surface 85 that defines the exit slit 84 so that liquid pumped through the exit slit 84 can flow over the top surface 85 and off therefrom through the spaced-apart slots 90.

In operation, the manifold structure 80, as part of the fountain-type dispenser 14, is disposed with its exit slit 84 horizontally adjacent to, but slightly spaced from, the horizontal portion of the recording element 12, the latter being positioned opposite the exit slit 84 by the roller 52. Liquid developer 16 pumped through the exit slit 84 by the pump 40 tends to form a bead of liquid developer 16 on the concave surface 85, but the regularly spaced-apart slots 90 provide spill over points for the bead. Hence, the liquid developer 16 emerging from the exit slit 84 flows laterally over the concave surface 85, in a direction substantially perpendicularly from the exit slit 84.

Referring now to FIG. 4, there is shown a manifold structure 100. The manifold structure 100 comprises an elongated body 102 either entirely of an electrically conducting material or of a plastic material covered with a cover of electrically conducting material. The manifold structure 100 is formed with an elongated slit 104 in a portion of a top surface 106.

Means are provided to cause liquid developer that emerges through the slot 104 to flow laterally over the surface 106 and to spill over opposite side edges 108 and 110 of the top surface 106. To this end, a plurality of regularly spaced-apart fingers 112, extending upwardly from a strip 114, are adhered to

opposite sides

116 and 118 of the manifold structure 100. The strips 114 are secured to the

sides

116 and 118 by any suitable means, such as by screws, for example. The fingers 112 may have a thickness of between 0.005 and 0.015 inch and may extend above the top surface 106 a distance of about 0.015 inch.

In operation, the manifold structure 100 functions substan tially the same as the manifold 20. Liquid developer pumped through the exit slit 104 initially tends to form a bead on the surface 106, the bead formation being aided by the extension of the fingers 1 12, acting as a dam, above the top surface 106. When the bead of liquid developer becomes large enough to overcome its surface tension, the liquid developer flows over the

edges

108 and 110 through grooves 120, formed between the upwardly extending fingers 112. This action tends to provide a reservoir of liquid developer on the top surface 106 with a lateral flow of the liquid developer from the exit slit 104 to the grooves 120.

Referring now to FIG. 5, there is shown a manifold structure 130, a further embodiment of the manifold 20. The manifold structure comprises an elongated body 132, as of stainless steel, having a top surface 134 formed with an elongated exit slit 136 therethrough. A ridge 138, of rectangular shape, surrounds the exit slit 136, and extends upwardly from the top surface 134 a distance of about 0.015 inch. The ridge 138 is coextensive with the side and end vertical walls of the elongated body 132.

The surface of the ridge 138 is roughened, as by sandblasting or abrading by any suitable means, to provide it with a plurality of minute grooves to enhance the wetting by the liquid developer adapted to flow thereover. Perferably the abrading should be in a direction perpendicular to the length of the exit slit 136 so that the minute grooves formed in the ridge 138 will be substantially perpendicular to the exit slit 136 too. In operation, liquid developer pumped through the exit slit 136 of the manifold structure 130 first forms a bead, or reservoir, on the top surface 134 and then flows over the ridge 138 at a plurality of points provided by the minute grooves in the roughened ridge 138.

Thus, each of the

improved manifolds

20, 80, 100, and 130 provides, along its opposite edges, a controlled rupture of the fluid surface tension of the liquid developer 16, thereby causing the liquid developer to flow essentially in directions substantially perpendicular to the exit slit and providing an even application of the liquid developer 16 to the recording element 12.

I claim:

1. A manifold for applying a liquid to a surface comprising a body having a generally horizontal top surface,

an exit slit formed through a portion of said top surface,

a plurality of spaced-apart ridges extending upwardly from said portion of said top surface, on opposite sides of, and spaced from, said exit slit, and forming a plurality of spaced-apart slots between adjacent ridges, whereby said liquid, when pumped through said exit slit, can flow over said top surface and off therefrom through said slots.

2. A manifold as described in claim 1, wherein said body comprises an electrically conductive material,

and

said top surface is substantially planar.

3. A manifold as described in claim 1, wherein at least said top surface of said body comprises an electrically conductive material, and

said top surface is concave.

4. A manifold as described in claim 1, wherein each of said plurality of slots extends in a direction transverse to the length of said exit slit.

5. A manifold for applying a liquid to a horizontal surface,

said manifold comprising an elongated body having a generally horizontal top surface,

said body having a pair of opposite'ends, a pair of opposite sides between said ends, and forming a pair of opposite edges with said top surface, and an exit slit between'said sides and extending in a direction intermediate said ends, said exit slit extending through a portion of said top surface, the length of said exit slit in said top surface extending in substantially the same direction as said opposite edges, and comprising means for directing said liquid to said horizontal surface, and

a plurality of spaced-apart ridges extending upwardly from said portion of said top surface adjacent said edges, and forming a plurality of spaced-apart slots between adjacent ridges, respectively.

6. A manifold as described in claim 5, wherein said body comprises electrically conductive material,

said top surface is substantially planar, and

said plurality of spaced-apart ridges comprise a plurality of metal fingers disposed along said opposite edges and in contact with said opposite sides and said top surface.

7. A manifold as described in claim 5, wherein said body comprises electrically conductive material,

said top surface is concave, and

said plurality of spaced-apart slots are formed along said opposite edges in directions transverse to the length of said exit slit.

8. A manifold as described in claim 5, wherein said body comprises electrically conductive. material and means for connecting a source of voltage thereto, and

said ridges and said slots are spaced from each other in a regular pattern, the width of said ridges being in the range between 0.020 to 0.060 inch, and the width of said slots formed between adjacent ridges being in the range between 0.010 and 0.030 inch.

Claims

1. A manifold for applying a liquid to a surface comprising a body having a generally horizontal top surface, an exit slit formed through a portion of said top surface, a plurality of spaced-apart ridges extending upwardly from said portion of said top surface, on opposite sides of, and spaced from, said exit slit, and forming a plurality of spaced-apart slots between adjacent ridges, whereby said liquid, when pumped through said exit slit, can flow over said top surface and off therefrom through said slots.

2. A manifold as described in claim 1, wherein said body comprises an electrically conductive material, and said top surface is substantially planar.

3. A manifold as described in claim 1, wherein at least said top surface of said body comprises an electrically conductive material, and said top surface is concave.

5. A manifold for applying a liquid to a horizontal surface, said manifold comprising an elongated body having a generally horizontal top surface, said body having a pair of opposite ends, a pair of opposite sides between said ends, and forming a pair of opposite edges with said top surface, and an exit slit between said sides and extending in a direction intermediate said ends, said exit slit extending through a portion of said top surface, the length of said exit slit in said top surface extending in substantially the same direction as said opposite edges, and comprising means for directing said liquid to said horizontal surface, and a plurality of spaced-apart ridges extending upwardly from said portion of said top surface adjacent said edges, and forming a plurality of spaced-apart slots between adjacent ridges, respectively.

6. A manifold as described in claim 5, wherein said body comprises electrically conductive material, said top surface is substantially planar, and said plurality of spaced-apart ridges comprise a plurality of metal fingers disposed along said opposite edges and in contact with said opposite sides and said top surface.

7. A manifold as described in claim 5, wherein said body comprises electrically conductive material, said top surface is concave, and said plurality of spaced-apart slots are formed along said opposite edges in directions transverse to the length of said exit slit.

8. A manifold as described in claim 5, wherein said body comprises electrically conductive material and means for connecting a source of voltage thereto, and said ridges and said slots are spaced from each other in a regular pattern, the width of said ridges being in the range between 0.020 to 0.060 inch, and the width of said slots formed between adjacent ridges being in the range between 0.010 and 0.030 inch.