US2586047A

US2586047A - Electronographic printing apparatus

Info

Publication number: US2586047A
Application number: US768308A
Authority: US
Inventors: William C Huebner
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-08-13
Filing date: 1947-08-13
Publication date: 1952-02-19
Anticipated expiration: 1969-02-19
Also published as: GB649060A

Description

1952 w. c. HUEBNER 2,586,047

ELECTRONOGRAPHIC PRINTING APPARATUS Filed Aug. 13, 1947 2 SHEETS-SHEET l WNW MIN

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INVENTOR. W LL! F! M E-HLIEZBNER BY F 2 55.12 a y 2 H J 1% FlTTElRNEYE Feb. 19, 1952 w. c. HUEBNER ELECTRONOGRAPHIC PRINTING APPARATUS 2 SHEETSSHEET 2 Filed Aug. 13, 1947 INVENTOR. WILLIFIM E-HLIEENER HTTDRNE 5 Patented Feb. 19, 1952 UNITED STATES PATENT OFFICE ELECTRONOGR A PHIC PRINTING APPARATUS 7 Claims.

- This invention relates to improved apparatus for and method of printing of the type wherein the ink is transferred from the inked image areas of the printing member of a printing couple to the surface of the print receiving material by means of the lines of force of an electro field of force to reproduce the image on said surface.

This type of printing is known as electronographic printing and reproduces the image on the print receiving material without the use of pressure or substantial pressure between the printing member and the print receiving material as distinguished from ordinary printing wherein the image is reproduced on the print receiving material by the exertion of substantial printing pressure between the printing member of the printing couple and the print receiving material.

Although reference has been made to the reproduction of an image on the print receiving material it will be understood that the apparatus may be employed to deposit a continuous coating on the print receiving material and in such instance the printing member will not be provided with image and non-image areas but the ink will be distributed over the entire printing surface of the member.

The dictionary definition of the term printing involves the use of pressure between the printing member and the print receiving material and hence there appears to be no available term in the English language which accurately defines the transference of ink from the printing member to the print receiving material where no printing pressure is employed. Consequently, throughout the present specification where the term printing and related terms are employed in describing and claiming the apparatus it is to be understood that such terms are used as being those nearest in appropriateness.

The expression field of force" is used herein to indicate the field or zone within which electronographic forces are sufliciently active or powerful to effect a transference of ink from one surface to another in the manner indicated. Also. the expression "lines of force is employed to indicate the forces themselves acting in a definite path or direction in effecting the transference of the ink.

It will be understood that the term ink employed herein is intended to refer to ink in the ordinary sense and also to any other substance which may be employed in reproducing on print receiving material an image carried by a printing member or in depositing on the material a coat- 2 ing coextensive with a predetermined surface area of the material.

As will be understood by those skilled in the art, the term image and related terms a used throughout the specification contemplates words, letters, delineations, drawings, pictures, illustrations, lines, figures and the like which may be reproduced on the print receiving material, and such term is used as embracing any one or any combination thereof.

An object of the invention is to provide an im= proved printing member for electronographic printing and which member is so constructed that the ink is expelled from the inside of the member to the outer printing surface thereof.

A further object is to provide a printing member as referred to in the last object and which member can be formed of metal or similar non= frangible material but will have a porosity equal to, or better than, a printing member formed of frangible ceramic material.

A-further object is to provide a printing memher as previously referred to and which member is so constructed that its degree of porosity can I be adapted to suit particular conditions as, for

instance, the use or" inks of different viscosity or consistency or the requirement for a heavy or a light deposit.

A further object is to provide a printing member wherein the printing surface is inked by expulsion of the ink from the interior of the member to the exterior thereof and which memher is so constructed that the ink can be readily expelled through the pores of the member by the lines of force of the electronographic field of force during the printing operation but will be held in the pores by capillary action except within the printing zone.

Another object or" the invention is to provide an electronographic printing apparatus and method wherein the printin zone extends over a wide area and thereby increases the time period in which the ink is transferred by the lines of force from the printing member to the print receiving material thus assuring the proper deposit of the nu; on the material with a minimum amount of current.

Another object is to provide an electronographic printing apparatus and method wherein relatively low voltages may be employed for the current which produces the electro field of force and thus the proper insulating of the various parts of the apparatus is facilitated and the safety factor of the use of the apparatus is increased.

A further and more specific object is to proaseaosw vide in an electronographic printing apparatus improved and novel discharge and attraction elements for producing the electro fields of force and particularly a substantially continuous field of force which extends over a large area.

A further object is to provide in an electronographic printing apparatus improved and novel discharge and attraction elements so constructed as to produce a multiplicity of electro fields of force so located as to merge with each other to form a substantially continuous electro field of force over a large area.

Further and additional objects and advantages residing in the invention and not specifically referred to above will become apparent hereinafter :iuring the detailed description which is to fol- Referring to the accompanying drawings:

Fig. 1 is an end view of a printing couple of an electronographic printing apparatus embodying the invention with the supporting frame for the couple omitted and is shown partly in section and partly in elevation;

Fig. 2 is a fragmentary sectional view throu h one end of the printing couple shown in Fig. 1 and is taken substantially on line 22 of Fig. 1 looking in the direction of the arrows:

Fig. 3 is a fragmentary sectional view on a larger scale of a portion of the printing member shown in Fig. 2;

Fig. 4 is a detached plan view of a length of the coil extension spring which is used in forming the printing member of Figs. 1 to 3 inclusive;

Fig. 5 is an end view of said length of coil p Fig. 6 is a fragmentary outside elevation of the printing member of Fig. 1;

Fig. 7 is a schematic view illustrating a portion 01' the discharge and attraction elements shown in Figs. 1 and 2 and indicating the se arate but merging fields of force extending between said elements;

Fig. 8 is a view similar to Fig. 1 but illustrating a modified form of apparatus embodying the invention;

Fig. 9 is an outside elevational view of a portion of the apparatus shown in Fig. 8 and is taken looking from the left-hand side of Fig. 8;

Fig. 10 is a view similar to Fig. 8 but illustrating a still different form of apparatus embodying the invention;

Fig. 11 is a fragmentary outside elevational view of the apparatus shown in Fig. 10 and is taken looking from the left-hand side of Fig. 10; and

Fig. 12 is a schematic illustration of the fields of force produced by the pins of the discharge and attraction elements of Fig. 10 and which pins are in staggered relationship as clearly indicated in said Fig. 12.

The printing couples illustrated in the drawing and embodying the present invention may be arranged as cooperating units in the frame of the printing press shown in my copending application Serial No. 689,490 filed August 9, 1946, now Patent No. 2,557,381 dated June 19, 1951.

Referring first to Figs. 1 to 3 inclusive, the printing couple, one end of which is shown therein, comprises a cylindrical printing member which is supported on a stationary shaft IS, with said shaft supported at its opposite ends in the frame N5 of the machine. The hubs ll of the disk-like members or end plates i8 of the printing member are rotatably mounted on the shaft IS in spaced relation and one or both of said end plates 4 a may be provided with a gear It for driving the rotatable printing member. The inner end of each huh I! is provided with a shouldered portion on which is fixed a supporting plate 20 formed of suitable electrical insulating material and contacting the inner side of the adjacent end plate I 8. The supporting plates 20 located adjacent to the opposite ends of the printing member are provided with machined inwardly facing shoulders and on which shoulders is mounted a metal cylinder 2! provided with a plurality of openings 22. These openings communicate at their inner ends with a cylindrical chamber 23 formed between the outer perforate cylinder 21 and an inner imperforate metal cylinder at which has its opposite ends extending into circular grooves formed in the supporting plates 20, with suitable packing positioned in said grooves to seal the connection between the inner cylinder and the supporting plates.

The outer circumference of the hub ll of one or both end plates [8 mounts a stationary ring 25 which is provided with a bore having connected thereto a supply conduit 26 extending from a suitable source of supply of ink. This bore communicates at its inner end with a passage 21 formed in the ring and extending axially with respect to the shaft i5 and communicating with an annular groove 28 formed in the outer side of the adjacent end plate i8. The annular groove 28 by means of one or more openings 20 formed in the end plate commnicates with the inner end of the space 30 between the end plate l8 and the adjacent supporting plate 20, said space 30 being formed by milling out the inner face of the plate 18. The outer end of the space 30 is in communication by means of one or more openings 3! formed in the supporting plate 20 with the cylindrical chamber 23 that is intermediate the outer perforate metal cylinder 2| and the inner imperforate cylinder 28. It will thus be seen that ink can be supplied to the cylindrical chamber 23 and this supply of ink may or may not be under pressure depending upon operating conditions. It is believed that gravity fiow of the ink to the chamber 23 will in most cases prove sufficient to adequately supply the ink to said chamber. However, in some cases it may be pref erable to have the ink supplied under slight pressure.

A closely coiled extension spring 32 is spirally wound under slight tension on the exterior of the outer metal cylinder 2! with its side edges in tight contact with each other and has its opposite ends suitably anchored to said cylinder. It will be understood that the slight tension under which the spring 32 is wound on the cylinder creates slight spaces between each coil of the spring and hence said wound spring may be designated as perforate. Reference to Figs. 4 and 5 will show that the coil spring preferably is of substantially rectangular configuration in cross section and that the outer surface of each coil is serrated as indicated at 33. It will also be noted that the outer surface of the outer perforate metal cylinder 2! is serrated over its entire area as indicated at Ma to provide minute passages or pores between the outer cylinder and the bpring 32 and which communicate with the openings 22 in the cylinder and with the slight spaces between each coil of the spring 32.

A strip 34 of fine mesh perforate material such as bronze screen or fiber glass is spirally wound on the outer cylinder over the wound spring 32 with the convolutions thereof oppositely disamen posed to the convolutions of the wound spring and with the' edges of the convolutions of the strip in close engagement. A second strip 35 of similar fine mesh perforate material is spirally wound over the first strip with the convolutions thereof being oppositely disposed to the convolutions of the first strip.

In this manner the outer cylinder 2| is provided with a smooth outer printing surface and the wound spring and the wound strips in effect are porous due to the spaces between the coils of the spring, the serrations on the outer side of the spring, and the fine mesh of the double layer of strips. Therefore, ink which is in the cylindrical chamber 23 can pass through the openings 22 in the outer cylinder 2| through the minute passages formed by the serrations 2la on the outer surfaces of the cylinder and through the pores of the spring and strips. Thus ink can be expelled from interiorly of the cylinder, i. e. from the chamber 23, to the outer surface thereof and over the entire area of the cylinder. However, unless the ink is expelled or propelled through the pores of the cylinder, spring and strips by some propelling force the ink will be retained in said pores by capillary action.

When the printing couple is employed for depositing a continuous coating on the print receiving material the entire area of the cylinder will be porous for the passage of ink. However, when the printing couple is to be employed for reproducing an image on the print receiving material then the outer surface of the cylinder will have the non-image areas masked or blocked against the passage of ink through the pores of such areas. These masked or block d non-ima e areas are indicated in Fig. 3 at 36 and can be formed on the cylinder in various ways. As an example of how the masked non-image areas can be formed. the cylinder may be covered with a light sensitive material such as bichrornated colloids, then the image areas are photographed onto the surface of the cylinder after which the outer surface of the cylinder is developed and the image portions thereof washed off while the light hardened non-image areas remain and form the masking non-image portions. It will be understood that the image and non-image areas on the cylinder 2i can be produced by any well-known process and since the production of these areas form per se no part of the present invention it is not believed necessary to further explain herein in greater detail the production of such areas on the cylinder. It should suffice to say that the image and non-image areas can be produced on the outer surface of the cylinder photographically. by galvanic process or simply by using a stencil and producing the areas thereon by a painting process.

From the foregoing description it will be noted that the cylinder 2| constituting the printing member of the couple is so formed that the ink can be expelled from interiorly of the cylinder to the exterior thereof. It will further be noted that this printing member is formed entirely of non-frangible material but at the same time it has a porosity equal to or better than a printing member formed of frangible material such as a ceramic material. Consequently, the member is not subject to breakage in handling or use and the effective life of the printing member is greatly increased. Also since the printing member is built up of the metal cylinder and the wound spring and strips, the porosit of the member can be readily controlled to suit various desired operating conditions.

Reference has already been madeto the fact that the ink unless forcibly expelled to the exterior of the printing cylinder remains in the pores thereof by capillary action. The invention contemplates effecting this forcible expulsion of the ink from the inside of the cylinder to the exterior thereof by means of the lines of force of electro fields of force and which further act to transfer the ink from the exterior of the printing member to the print receiving material. An improved way of producing the electro fields of force and embodying one aspect of the present invention will now be described.

A discharge member is located within the inner cylinder 24 and this member comprises axially spaced split hubs 31 which are stationarily clamped by clamping means 38 around electrically insulating sleeves 39 located on the stationary shaft I5 intermediate the latter and said hubs. The hubs 31 are provided with radially extending spokes 40, it being noted that three such spokes are shown and that the two end spokes are oppositely disposed and spaced apart substantially Of course instead of the separate spokes 40 the hubs could be provided with segmental disks forming one integral spoke. The outer ends of the spokes 40 mount a segmental electricall conductive rim 4| which is concentric to the inner cylinder 24 and the outer cylinder 2| and is spaced from but adjacent to the inner surface of the inner cylinder. The rim 4i mounts a series of circularly spaced radially projecting discharge blades or elements 42 which extend substantially the longitudinal length of the printing member, that is, from closely adjacent one supporting plate 2t to closely adjacent the other supporting plate. The discharge blades or elements 42 have their free ends beveled to a sharp edge and located closely adjacent to the inner surface of the inner cylinder 24.

Electrically connected to the rim 4i is a conductor 43 in the form of a rod which extends radially of the printing member and passes through openings in the hub Bl, insulating sleeve 39 and shaft it to the hollow interior of the latter. The inner end of the conductor 43 is electrically connected to an electrical conduit 44 housed in an insulating tube 45 and extending through the hollow shaft 55 and connected to one pole of a source of high potential electric energy (not shown).

The attraction member is arranged exteriorly of the printing cylinder and comprises supporting end plates 48 spaced apart in a direction axially of the printing member and substantially semi-circular in shape and concentric to the printing cylinder and each provided at its 0pposite ends with laterally extending portions 4l electrically insulated from but supported by the frame of the printing apparatus. A curved rim plate 48 extends between the supporting end plates 46 and is secured thereto by suitable means as, for instance, welding. The run plate 48 is substantially semi-circular and is concentric to the printing cylinder and has secured to it circularly spaced radially projecting attraction blades or elements 49 which extend longitudinally from one end plate 46 to the other end plate 46 and have their ends secured to said plates as by welding. The free ends of the attraction blades or elements 49 are beveled and are spaced radially outwardly from the outer surface of the printing cylinder and are in alignment, respectively, with the discharge blades or elements 42 within the printing cylinder. The nm plate 48 has electrically connected to it a conductor 50 which in turn is connected to an electrical conduit that is connected to the other pole of the source of high potential electric energy.

From the foregoing description it will be understood that when the high potential electric current is applied to the conduits 44 and 5| that the discharge blades or elements 42 and the attraction blades or elements 49 are in the circuit and that a separate electro field of force extends across the gap between each cooperating pair of discharge and attraction blades or elements as clearly indicated in Fig. 7. The blades are so positioned that the separate electro fields of force extending between them combine to produce a substantially continuous electro field of force which is substantially semi-circular in extent and is co-extensive with the complete longitudinal length of the printing couple. Consequently, a printing zone covering a wide area is provided which results in increasing the time period in which the ink is transferred by the lines of force of the fields of force from the printing cylinder to the print receiving material and thereby assures the proper deposit of ink on the material. by the combined fields of force and the fact that the transfer of ink occurs throughout a relatively long period of time, relatively low voltages may be employed for the current which produces the electro fields of force thus simplifying the proper electrically insulating of the various parts of the apparatus and also providing an improve safety factor.

Reference to Fig. 1 shows that the web 52 of print receiving material extends around the outside of the printing cylinder and is in contact therewith substantially throughout an arc of 180. In other words, the area of the print receiving material which is in contact with the printing cylinder at any given moment during the printing operation is substantially coextensive with the area of the combined fields of force. It will be understood that during the printing operation the printing cylinder is rotated through a drive train (not shown) and applied to the gear 19 and that the web of print receiving material 52 travels around the rotating printing cylinder in a predetermined direction and at a predetermined rate with suflicient tension being imparted thereto by means not shown to hold the web of print receiving material in proper contact with the printing cylinder, It will also be understood that the electro lines of force of the fields of force act to expel the ink from the cylindrical chamber 23 through the pores of the printing cylinder and to deposit the same upon the adjacent surface of the print receiving material. These deposits may be continuous if the printing cylinder is not provided with masked non-image areas and in such an event the deposits constitute a coating on the material. On the other hand, if the outer surface of the printing cylinder is provided with masked non-image areas and unmasked image areas, then the ink will only be expelled from the cylinder and deposited on the print receiving material in areas corresponding to the from each other.

Also, due to the extensive area covered image areas and thus the desired image will be lustrated. Insofar as the parts are identical with the parts of the printing couple illustrated in Figs. 1 to 7 inclusive they need not be redescribed and the same reference characters may be used to designate such parts. Theprinting couple illustrated in Figs. 8 and 9 differs from the previously described printing couple by the provision at each of the opposite ends of the attraction member of a pair of rollers 53, with the rollers of each pair being circularly spaced The rollers 53 engage the outer side of the web 52 adjacent the longitudinal edges thereof and frictionally rotate in contact with said web. The rollers 53 on their circumferences are provided with spiral contact surfaces 54 with the contact surfaces of the rollers at one end of the couple oppositely disposed with respect to the contact surfaces of the roller at the other end thereof. The rollers 53 thus function to pull the opposite longitudinal edges of the print receiving material outwardly to stretch out any irregularities or wrinkles which may be in the web. The rollers 53 are rotatably mounted on pins 55 which are fixedly supported in but insulated from suitable bosses formed on the frame of the printing apparatus. It will be understood that the supports for the rollers may be adjusted to provide for the proper contact with the web of print receiving material.

In Figs. 10 and 11 a still different form of the invention is illustrated but insofar as the parts are identical with the parts in the previously described forms the description thereof is not repeated and the same reference characters are applied to these parts. In this form the rim ll of the discharge member in place of mounting discharge blades or elements mounts radially extending discharge pins or elements 56. These pins or elements 56 are arranged in three circularly spaced groups with the pins of each group staggered as indicated in Fig. 12. It will be noted by reference to Fig. 12 that the pins or elements 56 of each group are arranged in a series of rows of pins or elements with the pins or elements of one row staggered or displaced in a direction longitudinally of the printing cylinder and with respect'to the pins or elements of the adjacent rows.

In the printing couple shown in Figs. 10 and 11 the attraction member is in the form of three segmental sections which are circularly spaced with respect to each other and are individually supported in and insulated from the frame of the printing apparatus. Each segmental section of the attraction member comprises a rim plate 51 which carries a series of rows of radially projecting attraction pins or elements 58 arranged similarly to the pins or elements 56 of the discharge member and with each pin or element 58 aligned with a corresponding pin or element 56. Each segmental section of the attraction -member is electrically connected to the same pole and common source of high potential electric energy.

Stationary shafts 59 are carried by but insulated from the frame of the apparatus and extend longitudinally of the printing couple intermediate the spaced sections of the attraction member. Each shaft 59 rotatably mounts a roller 6!] which extends longitudinally of the printing couple and is in frictional contact with the outer surface of the web 52 of the print receiving material and as said web travels around the printing cylinder, the rollers rotating in contact therewith iron or smooth out wrinkles or any unevenness in the web. It will be understood that the shafts 59 are adjustably supported by the frame so as to enable the rollers to be properly positioned in contact with the web of print receiving material.

Reference to Fig. 12 will show that the electro fields of force between each cooperating pair of aligned discharge and attraction pins or elements merges with the electro fields of force extending between the adjacent and surrounding pairs of discharge and attraction pins or elements and hence the separate but merging electro fields of force combine in effect to produce a substantially continuous electro field of force over a wide area and extending the complete width of the web. Inasmuch as three of such extensive combined electro fields of force are provided it will be seen that the printing Zone extends substantially 189 of the printing cylinder and substantially over the entire area of the web that is in contact with the printing cylinder at any given moment. This produces the advantages already pointed out in connection with the description of the printing couple illustrated in Figs. 1 to 7 inclusive.

Although a number of embodiments of the invention have been illustrated and described herein it will be understood that the invention is susceptible of many various modifications and adaptations within the scope of the appended claims.

Having thus described my invention, I claim:

1. In an electronographic printing couple, a rotatable cylindrical printing member having an outer Wall provided with porous image portions and imperforate non-image portions, a stationary discharge member located within said printing member and adapted to be connected to one pole of a source of high potential electric energy. a stationary attraction member located exterior-1y of said printing member in spaced relation th reto and adapted to be connected to the other pole of said source of energy, said discharge and attraction elements being substantially coextensive in length with said printing member and being curved concentrically to the curvature of said printing member and correlated to each other and extending through a substantial arc, said printing member being provided interiorly thereof with means for containing an ink supply and in communication with the pores of said image portions, said printing member being adapted to have a web of print receiving material passing around its exterior circumference in contact therewith throughout an are substantially coextensive with the discharge and attraction members with said web located within the space between the printing member and the attraction member and moving in timed relation to said printing member, wherefore when said discharge and attraction members are energized an electrostatic field of force is created therebetween with the lines of force thereof passing through the outer wall of the printing member and acting to migrate the ink from the ink 19 supply within the printing member through the pores of the image portions and upon the print receiving material to reproduce the printed image thereon.

2. An electronographic printing couple as defined in claim 1 and wherein the discharge and attraction members are provided on their adjacent surfaces with a plurality of projections with the projections of the discharge member extending toward the inner side of the outer wall of the printing member and the projections of the attraction member extending toward the outer side of the outer wall of the printing member.

3. An electronographic printing couple as defined in claim 2 and wherein the projections on the discharge and attraction members are in the form of blades projecting radially with respect to the printing member and extending longitudinally thereof.

4. An electronographic printing couple as defined in claim 2 and wherein the projections on the discharge and attraction members are in the form of spaced pins projecting radially with respect to said printing member.

5. An electronographic printing couple as defined in claim 2 and wherein the projections on the discharge and attraction members are in the form of pins arranged in circularly spaced groups with each group including circularly spaced rows of pins, with the pins of one row staggered with respect to the pins of the adjacent rows.

6. An electronographic printing couple as defined in claim 2 and wherein are provided rollers spaced circumferentially of the printing member and extending longitudinally thereof and disposed to contact the web of print receiving material to smooth out wrinkles or uneven portions thereof.

7. An electronographic printing couple as defined in claim 6 and wherein said rollers are provided with spirally disposed contacting surfaces acting to press the web of print receiving material with a pressure directed laterally outwardly of the side edges of the web.

WILLIAM C. HUEBNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 751,947 Schoening Feb. 9, 1904 1,337,530 Page Apr. 20, 1920 1,575,508 Rosenhouer Mar. 2, 1926 1,856,181 Burkholdt May 3, 1932 2,152,077 Meston et a1 Mar. 28, 1939 2,224,391 Huebner Dec. 10, 1940 1,820,194 Huebner Aug. 25, 1931 FOREIGN PATENTS Number Country Date 602,985 Great Britain June 7, 1948