US2908221A - Method of and apparatus for printing - Google Patents

Description

0a. 13, 1959 G. R. BRODIE 2,908,221

METHOD OF AND APPARATUS FOR PRINTING 2 She ets-Sheet 1 Filed Nov. 13, 1952 r h niv @NVENTOR GEORGE R. Bacon;

2 Sheetcs-Sl'leet.v 2

s, R. BRODIE METHOD OF AND APPARATUS FOR PRINTING Filed No v. 1-3. 1952 INVENTOR GEORGER BRODIE lamu'ylm ATTORN Y5 2,908,221 Patented Get. 13,

METHOD OF AND APPARATUS FOR PRINTING George R. Brodie, Lower Merion Township, Montgomery County, Pa., assignor to Fredk Levey (30., 1110., New York, N.Y., a. corporation of New York Application- November '13, 1952, Serial No. 320,263

11 Claims. (Cl. 101350) This invention relates to the art of printing and more particularly to that aspect of the printing art in which there is used a' printing ink containing a volatile solvent and subject to drying by the evaporation ofthe solvent, e.g,, the so-called quick-drying evaporative type inks.

In the operation of conventional rotary printing presses, the ink is supplied to what is known as a fountain roller and from thence is passed by means of a series of intermediate rollers to the plate cylinder. The purpose of these intermediate rollers is to effect an even distribution of the ink about the circumference of the inking rollers and to assure the application of the right. quantity of ink to: the plate cylinder.

Frequently, the density of the printing surfaces or plates at one longitudinal section of the plate cylinder is very different from that at another longitudinal. section. The rate at which ink must be supplied to the more dense printing surfaces is, of course, greater than that at which the ink is supplied to the less. densesurfaces. To accommodate such conditions, it is. conventional practice to apply a thicker film of the ink tothatsection of the. fountain roller corresponding to. the more dense printing surfaces. This is usually accomplished by means of a doctor blade which is adjustable.v tov fit more closely against the fountain roller at. the sections thereof where lessink is required. for the corresponding section of the plate cylinder.

As a film of ink of the: evaporative type is. passed along this series ofrollers. leading from. the fountain roller to the plate cylinder, there is considerable evaporation. of the volatile ink solvent. This condition is aggravated: by the fact that the rate of evaporation. of. the solvent is substantially uniform over the entire surface of any given ink transfer roller while the thickness of the ink film, and consequently the volume of ink, is usually not uniform. Therefore, the proportion of solvent evaporated, relative to the amount of ink from. which it is evaporated, will be greater at those sections of the rollers carrying the thinner film of ink and consequently, the. ink at. those sections will become more tacky than will the; ink at other sections Where the ink film is thicker. Indeed, at some sections of the plate cylinder theink may become so tacky as to pull and tear the paper web.

To avoid this condition, it has been proposed to spray additional solvent. onto those sections of the series of rollers where. the ink tends to become. more tacky so as to compensate for the subsequent evaporation. In other words, additional solvent would be sprayed. onto: those areas of the ink transfer rollers carryingthe thinner films of This proposal, however, has proved unsatisfactory. It is difficult to adjust the spraysand to prevent dripping of the solvent onto the rollers and:- to. concentrate the spray at the desired areas of the rollers. The spray tends to fiy. and dilute the ink films on other areasv of the rollers of the press. Also an excessive amount. of equipment is required for such spraying of the. volatile; solvent.

A further difiiculty encountered in using inks of this type on rotary printing presses is that the ink film tends to dry on the rollers and on the printing surfaces when the presses are stopped.

It is an object of my present invention to avoid. eX- cessive drying of the ink on the ink transfer rollers due to solvent evaporation and to avoid the difiiculties heretofore experienced in attemptsto compensate for evapo ration by spraying with additional ink solvent. A fill:- ther object of the present invention is to prevent excessive drying of the ink while the presses arenot. in open ation, or to avoid the consequences of such drying. These and other objects are attained by my present invention as will appearfrom' the following detailed descrip- .tion thereof.

My present invention provides an improved. method of supplying additional ink solvent to one or more of the ink transfer rollers or longitudinal. sections of such rollers and also provides improved apparatus especially adapted to the carrying out of the process.

In accordance with my invention addedl solvent isapplied toat least one off the ink-transfer rollers, advantageously the first roller of the series following the fountain roller and ductor, by rapidly rotating a cylindrical brush in close proximity to but out ofcontact with said roller or rollers of the series, about an axis substantially parallel to the axis of said ink-transfer roller,.wetting the bristles of said brush with the solvent and thus throwing the solvent from the brush onto the roller, in part at least by centrifugal force; The brush is with advantage, but not necessarily, coextensive. in length with the mktransfer roller. As an alternative, it maybe made up of a plurality of cylindrical segments mounted on a common shaft. applied to'the bristles by rotating the brush' roll'er'in contact with thesurface of a rotating cylinder'carrying a film of the solvent, as hereinafter more fully described; However, other means may be employed for' applying the solvent to the bristles.

The invention will be more particularly'describedi and illustrated by reference to the accompanying drawing of a particular advantageous embodiment thereof and of which Fig. 1 represents asomewhat fragmentary vertical sectional view of a rotary printing press embodying the invention; I I

Fig. 2 is asomewhat enlargedplan view of one means for applying theink solvent to conventional ink-transfer rollers; and

Fig. 3 is an enlarged fragmentary vertical sectional view of thebrush roller and a rotating.v cylinder adapted to apply the solvent to thebristles of the brush roller.

Referring more particularly to Fig. 1, the printing press supporting frame is represented at 1". Supported by this frame is a conventional fountain roller 2; ink trough 3* and a series of ink transfer rollers 4", 5, 6, 7, and 8. A pool of ink 9 is maintained in the trough 3 in contact with the fountain roller 2' and the thickness of the ink film applied toroller 2 is controlled in the usual manner by the adjustable doctor blade indicated at .10. Ink is conveyed from the fountain roller 2 to the ink-transfer roller 4 by means of the ductor 1-1 rotatably supported by the bracket 12 which in turnis supported by the frame 1 and which is adapted tobemoved back and forth. by the lever arm 1-3 so astobebrought alternately into contact with the surface of the fountain roller 2 and the ink-transfer roller 4, all of which is well understood in the art.

A brush roller 14 provided with flexible, "substantially. radially extending" bristles I5- is--alsosupported by the printing press frame 1 and is so positioned withrespect toia. rotating cylinder 16 that the tips ofthe bristles are in contact with the cylinder surface of rollers 16,

The solvent is, especially advantageously,

in Fig. 2 of the drawing. The segmental cylinder 16 is supported by a shaft 18 which in turn is supported by the printing press frame 1 and is adapted to be rotated by suitable means, advantageously. a variable speed electric motor, indicated at 19. Secured to the shaft 18 is a gear 20 adapted to mesh with gear 21 secured to a splined shaft 22, the latter also being supported by the printing press frame 1.

Spaced along thesplined shaft 22 and keyed thereto is a series of cylindrical discs 23 corresponding to the cylindrical segments of cylinder 16. 'These discs 23 are adapted to be moved longitudinally along the shaft, even during operation of the press, by means of the respective .yokes 24 adjustably supported by the rod 25 and adapted to be held in the desired position by means of the tension bolts 26.

The brush roller 14 is supported by shaft 27 which, in turn, is supported by the press frame 1 and is adapted to be rotated by suitable means advantageously by a variable speed electric motor represented at 28.

Positioned just below the series of cylindrical discs 23 and coextensive therewith is a trough or other container 29 adapted to hold a body of the ink solvent.

In operation, an ink film is applied to the ink-transfer rollers in the customary manner, which is well-known to the art and need not here be described. Ink solvent is supplied by any suitable means to the solvent trough 29 so as to maintain therein a body of solvent of suificient depth to wet the cylindrical surfaces of the discs 23.

The segmental cylinder is rotated, as by means of the motor 19 and, in turn, drives the splined shaft 22 through the gear train 20 and 21. The splined shaft, in turn, causes the discs 23 to rotate, carrying on their surfaces a film of the ink solvent from the trough 29 which is conveyed to a of the cylinder 16.

The solvent film is picked up from the segments of cylinder 16 by the bristles of the corresponding segment of the brush roller, the latter being operated in a clockwise direction. As previously indicated, the bristles are, with advantage, flexed somewhat as they pass in contact with the segments 17 and, when released, flip the particle of solvent carried by the bristle tip onto the roller 4, as more clearly shown in Fig. 1 of the drawings. The throwing of the solvent from the bristle tips onto the roller 4 is also promoted by centrifugal force. Where desired, the bristle tips may make only slight contact with the surfaces of the segments 17 so that there is little or no flexing, in which case a particle of solvent may be thrown from the bristle tips to the roller 4 substantially solely by centrifugal force. However, some flexing of the bristles is usually desirable.

To avoid the retention of any substantial amount of solvent on the bristle tips, a bar such as shown at 30, supported by the press frame, may be provided to effect a second flexing of the bristles. As a further precaution against the throwing of particles of solvent onto portions of the press where it is not desired, a shield, such as shown at 31 may be provided. However, usually such shield is not required. The shield shown is provided at its lower end with a trough 32 adapted to catch any solvent which might be thrown against the shield and, from whence, such solvent may be withdrawn by any suitable means.

As previously noted, it is frequently desirable to apply different quantities of solvent to different longitudinal sections of the ink-transfer rollers. This is accomplished by the apparatus shown by adjusting the position of the discs 23 with respect to the corresponding segments of roller 16 to effect greater or less surface contact becorresponding spaced segment tween the corresponding rotating elements. For instance, the position of the second and third discs from the right of Fig. 2 are so positioned with respect to the corresponding segments of roller 16 as to give maximum contact, While the position of the first disc from the left is so adjusted as to give no contact at all. Where there is maximum contact there is, of course, greater transfer of solvent to the brush roller and, from thence, to the corresponding longitudinal section of the ink-transfer rollers. Should it be desired to apply no added solvent whatever to some section of the ink-transfer roller, the disc corresponding to that section will be so adjusted as to avoid contact with the segments of roller 16.

As previously noted, the position of the several discs may be separately adjusted even during operation. Thus the amount of solvent applied to any section'of the inktransfer rollers may be varied at will without interfering in any way with the operation of the press.

A further advantage of my present invention is that it provides improved method and means of applying an extraordinary amount of solvent to the ink-transfer rollers at any time when a shutdown is contemplated This may be accomplished by increasing the speed of rotation of the cylindrical surfaces '17 and 23 by means of the variable speed motor 19, thus applying a maximum amount of solvent to the respective longitudinal sections of the ink-transfer rollers and plate cylinder where most needed, by virtue of the previously selected setting of the discs 23.

Under usual conditions, the quantity of additional solvent required by reason of a shutdown will be automatically applied to the ink-transfer rollers and plate cylinder, without readjusting the speed of rotation of either the brush roller or solvent-supplying surfaces 17 and 23, by continuing the operation of these elements at their normal speed while the press is gradually slowing down and starting up.

Where operation of the press is discontinued for only a short period, suflicient solvent can usually be supplied, as just described, to prevent excessive drying of the ink on the ink-transfer rollers and on the plate cylinder. However, where conditions require, additional solvent may be supplied as operation is resumed to soften any ink which may have become excessively tacky.

As appears from the foregoing description of the invention, added solvent may be applied to a single longitudinal segment of the ink rollers, to any selected segments, or over the entire length of these rollers, as the occasion requires. This may be accomplished by simple adjustment of the positions of the rotating elements 23 with respect to the corresponding elements 17 without interfering with press operation. I It will be understood that the invention in its broader aspect is not restricted to the specific means shown for applying the solvent to the brush roller. However, the mechanismshown is especially advantageous for that purpose because of the nicety of control of solvent quantities applied to the respective longitudinal sections of the ink transfer rollers and flexibility of operation. The rate at which the solvent is supplied to the rollers may be varied to a considerable extent by varying the speed of rotation of the solvent supplying surfaces either with, or Without, changing the speed of rotation of the brush roller. 7 i

Where the position of the brush roller with respect to the cylinder 16 is such as to cause a flexing of the bristles 15, the speed of rotation of the brush roller is subject to very considerable variation. However, where the position of the brush roller with respect to cylinder 16 is such as to cause little or no flexing of the bristles and no flexing rod, such as shown at 30,- is used, the speed of rotation of the brush cylinder should be such as to throw the solvent [from the bristles onto roller 4 by centrifugal force alone. In the latter case, the speed of rotation of the brush roller will depend somewhat upon the diameter of the roller but usually should be within the range of about 300 to 1800 rpm.

a uv-s I claim:

1. A rotary printing press comprising a series of substantially parallel ink-transfer rollers, means for applying a film of ink to said ink transfer rollers and means for applying an ink solvent in controlled, variable amounts to the ink film on the respective longitudinal'sections of the ink-transfer rollers comprising a cylindrical brush roller having substantially radially projecting flexible bristles adapted to be rotated about an axis substantially parallel to the axis of said ink-transfer rollers and positioned in close proximity to, but out of contact with, at least one of said ink-transfer rollers, a rotatable cylindrical body having its axis substantially parallel to the axis of said brush cylinder and adapted to be rotated in peripheral contact with said bristles but out of contact with the surfaces of said ink-transfer rollers and means for applying the ink solvent in controlled, variable amounts to the respective longitudinal sections of the cylindrical body.

2. The apparatus of claim 1 in which the cylindrical body is made up of a series of longitudinally spaced radially projecting segments.

3. The apparatus of claim 2 in which the means for applying the solvent film to the respective segments of the cylindrical body comprises a series of cylindrical discs mounted on a rotatable shaft parallel to the axis of the cylindrical segments and adapted .to be rotated by the shaft in peripheral contact with corresponding segments, and means for wetting the peripheral surfaces of the several discs with the solvent.

4. The apparatus of claim 3 in which said discs are adapted to be moved along the shaft, thereby varying the width of the peripheral contact between the respective segments and the corresponding discs.

5. In the process of printing with an evaporative type, quick-drying ink whereby the ink is conveyed as films of controlled thickness along a series of parallel ink-transfer rollers, the ink films on the respective longitudinal sections of the rollers being of variable thickness, the method of applying an ink solvent in controlled amounts to the ink film and for varying the amount of solvent applied to the respective sections, which comprises mechanically throwing fine particles of the solvent against the surface of the ink film, in part at least by centrifugal force, by rotating a cylindrical brush roller comprising substantially radially projecting flexible bristles, in close proximity to, but out of contact with, one of said ink-transfer rollers, the axis of said brush roller being substantially parallel with the axes of said transfer roller, applying the ink solvent to the tips of said bristles, whereby the solvent is thrown from said bristles onto the film of ink carried by the transfer roller, and separately controlling the amount of solvent applied to the bristles of the respective longitudinal sections of the brush roller.

6. The process of claim 5 in which the solvent is thrown from the bristles onto the ink film, in part at least, by a flexing of the bristles.

7. The process of claim 5 in which the quantity of ink solvent applied to the tips of said bristles of the respective longitudinal sections of the brush roller is inversely proportionate to the thickness of the ink film carried by the corresponding sections of the ink-transfer roller.

8. The process of claim 5 in which the ink solvent is applied to the tips of said bristles by rotating the cylindrical brush with its bristles in peripheral contact with a rotating cylinder and controlling the amounts of solvent applied to the respective longitudinal sections of the ink film by applying separately controlled amounts of the solvent to the corresponding longitudinal sections of the cylinder.

9. In the process of printing with an evaporative type, quick-drying ink whereby the ink is conveyed as films of controlled thickness along the series of parallel inktransfer rollers, the ink films on the respective longitudinal sections of the rollers. being of a variable thickness, the method of applying an ink solvent in controlled amounts to the ink film and for varying the amounts. of solvent applied to the respective longitudinal sections which comprises throwing finely divided particles of the solvent against the surface of the ink film, in part at least by centrifugal force, by rotating a cylindrical brush having substantially radially projecting flexible bristles in close proximity to, but out of contact with, one of said ink-transfer rollers, the axis of said bnush roller being substantially parallel with the axis of said transfer roller, applying the ink solvent to the tips of said bristles by rotating the cylindrical brush with its bristles in peripheral contact with the surfaces of a roller comprising a series of radially projecting cylindrical sections and applying varying selected amounts of the solvent to the respective longitudinal sections of the roller.

10. The process of claim 9 in which the ink solvent applied to the respective sections of the roller by ro tating a cylindrical disk in peripheral contact therewith while wetting another portion of the periphery of the disk with the solvent.

' 11. The process of claim 10 in which the amount of solvent applied to the respective sections of the roller is controlled by varying the width of peripheral contact between said section and the corresponding disk.

References Cited in the file of this patent UNITED STATES PATENTS Re. 1,649 Fuzzard Apr. 5, 1864 169,268 Isbell Oct. 26, 1875 639,382 Harley Dec. 19, 1899 1,185,670 Hoe June 6, 1916 1,207,258 Wood Dec. 5, 1916 1,262,707 Smith Apr. 16, 1918 1,574,063 Cadgene et a1 Feb. 23 ,1926 1,617,875 Swanson Feb. 15, 1927 1,686,968 Harber Oct. 9, 1928 1,778,476 Wood Oct. 14, 1930 1,837,702 Canfield Dec. 22, 1931 1,945,631 Frankboner Feb. 6, 1934 2,154,544 Taylor Apr. 18, 1939 2,275,148 Hornbeck Mar. 3, 1942 2,283,830 Taylor May 19, 1942 2,299,994 Kokay Oct. 27, 1942 2,347,619 Taylor et a1 Apr. 25, 1944 2,578,921 Cramer Dec. 18, 1951 2,707,916 Smith et a1. May 10, 1955 FOREIGN PATENTS Germany Nov. 12, 1923

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