US2833212A - Ink motions for printing machines - Google Patents

Description

y 1958 c. A. HARLESS' 2,833,212

' INK MOTIONS FOR PRINTING MACBINES Filed Feb. 21, 1955 I 2 Sheets-Sheet 1 FIG. I.

INVENTOR May 6, 1958 c. A. HARLESS INK MOTIONS FOR PRINTING MACHINES 2 Sheets-Sheet 2 Filed Feb. 21, 1955 A ORE United States Patent 2,833,212 INK MOTIONS FOR PRINTING MACHINES Charles A. Harless, Riverside, Conn., assignor to R. Hoe & Co., Inc., New York, N. Y., a corporation of New York Application February 21, 1955, Serial No. 489,655

8 Claims. (Cl. 101-349 between rollers is provided to smooth the ink into a.

reasonably uniform film circumferentially of the form rollers, and an axially reciprocating movement is provided for some of the rollersso as to distribute the ink axially of the form rollers.

In typical previously used ink motions, the soft surfaced rollers are free running, while the hard surfaced rollers are gear driven, and the required gearing for driving the cylinders rotatably, and the mechanism for axially reciprocatingsome of them, places rather definite limitations upon the size of rollers and also upon the location of their axes. A succession of hard surfaced rollers or ink drums must, by reason of the interposition between them of soft surfaced transfer rollers, rotate in the same direction, requiring the use of intermediate idle gears,

reference to the axially reciprocating mechanism. Typical heavy letterpress equipment may include two or three gear driven and axially reciprocated cylinders, the number of'these cylinders found necessary depending upon the type of ink used and the type of printing being done.

The limitation of available space where three axially reciprocated elements are used, frequently limits the possible location of the ink rail or other element supplying ink to the first cylinder of the ink motion.

The general object of the present invention is to pro-f,-

vide an ink motion having improved ink distributing capacity, while at the same time providing a more compact installation as well asa simplified and easily accessible arrangement of rollers.

It has been found that by utilizing a set of three rollers for transferring ink from one vibrator or axially reciproeating cylinder to the next, a very definite improvement in ink distribution may be obtained. At the same time, the construction is simplified and it becomes possible to mum etficiency and ease of adjustment.

In the drawings:

Fig; 1 is an end elevation, partly broken away, on the section planes indicated generally at 1-1 and 1'--1' in Fig. 2;

Fig. 2 is a section on the line 2-2 of Fig. l; and

Fig. 3 is an enlargement of a part of Fig. 2.

The printing unit shown is of the familiar arch type, havingtwo printing couples 10, 11 and 10, 11'. The

frame structure 12 is indicated in phantom. The right and left hand sides of the unit differ only in that the rollers relocate the ink pump or ink rail in a position for maxiand, these gear centers must be located properly with the drum 20.

and cylinders are positioned in transposed horizontal relation, so corresponding rollers in each side of the unit are accessible from the outside of the frame. For completeness of illustration, the parts are shown on two different section planes, so that the roller sockets or mountings are shown in the right hand half of the unit and the gearing on the left. It will be understood that roller sockets and gearing as shown are provided for both halves of the unit, and corresponding parts are identified by corresponding reference numerals, with the reference numerals applying to the right hand side of the unit having prime superscripts.

The frame and gearing arrangement is generally the same as shown in prior Harless application Serial No. 421,379, filed April 6, 1954 for Inking Mechanism for Printing Machines, and the roller socket mountings are of the type shown in prior Harless application Serial No. 344,444, filed March 24, 1953 for Ink Roller Mounting.

Each ink motion includes a first ink drum 20 to which the ink is applied by an ink rail 21, connected to a pump 22, the ink pump and ink rail arrangement being of the type shown in prior Worthington application Serial No. 440,690, filed July 1, 1954, for Inking Mechanisms. The ink drum 20 as well as the second ink drum 23 is driven by gearing including a gear 25 fixed to the shaft of the plate cylinder 11, an idle intermediate gear 26, a gear 27 fixed to the shaft of the ink drum 23, an idle gear 28 and a gear 29 fixed to the shaft of ink drum 20. The drums 20 and 23 are reciprocated axially by means ,ofa' drive mechanism 30, the specific form of which forms no part of the present invention and the details of which are shown in prior Harless application Serial No. 421,379, mentioned above. The peripheral speeds of . drums 20 and 23 are equal and are the same as the peripheral speed of the plate cylinder 11.

The ink motion alsoincludes form rollers 31 and 32 for transferring ink from the ink drum 23 to the plate cylinder 11, and a train of rollers 33, 34 and 35 for trans- 'ferring ink from the drum 20 to the drum 23, as well as rider or distributing rollers 36and 37 cooperating with An additional rider 38 may be provided where indicated in dotted lines, when the direction of rotation of the ink motionis reversed.

The various roller socket mountings 4045 are arranged to permit adjustment of the positionof the rollers with reference to their cooperating ink drums and the plate cylinder, as usual. The rollers 31, 32, 33, 35, 36,

37 and 38 are all soft surfaced rollers, rubber surfaced rollers being preferred, but rollers surfaced with other compositions being useable as well. The roller 34, however, is a hard surfaced steel drum having a shaft 51 mounted in bearings 50 held in the frame 12. These are thrust bearings and hold the drum so as to prevent its motion axially.

The soft surfaced rollers 33 and 35 are adjusted with reference to the hard surfaced drums 20, 23- and 34 for a flat of about inch to /2 inch, the precise flat being selected by the pressman according to the ink and operation conditions so as to obtain the best ink distribution.

A major. feature of the present invention consists in the combination with the two successive gear driven and 3 3 (driven by drum and roller (driven by"dnim 23), sothatthe system of rollers 20 33-34352 3 and gears 27-28'2"9 taken in the cyclical order stated form a closed system in which it is conceivable that at any of the contacts or cuts 20 33, 3334,-3435 or 35-23 the driving torque may -be from either "one of the pair'in que's'tiondto the other and may,-hen'ce, with respect to a given roller, be either an acclerating'torque or a decelerating torque. The torque transmission at any given contact will-be a function of the fiat end of the ink thickness as well as any other'factors influencing the friction or viscous drag "between rollers.

The precise speed relationships between h ard and siift surfaced'r'olle'rs in driving contact under ink motion con.- ditions Iare not fully understood :High speed,photographysho wmhowever, that the condition at a' cut in an ink motion is of an oscillating or variable character as distinguished from a. smooth and steady rotation and transfer or ink filmgas the ink can be seen to well out betweenjollers adjacent the flat, creating a body'ofink which disappearsand then reforms. It is probable that the-driveconditions and, :hence, speed of the various rollers which are not geardriven are unstable and variable, it being likelyfthat there is a tendency for slip at agiven cut to reduce the thickness of ink film in the "flat, thereby giving -'the"driving roller a better grip on the driven roller so as to, accelerate the latterand. reduce the slip,.-perrnitting a thicker to pass, which, again, reduces the 'grip;oftheidriving roller on the driven roller, permitting theslip to increase, creating a cycle of unknown period and producing an average drive speed ratio which is ex- 'tremely unstable and sensitive to variationsinthe various ccindfitio'ns. I

Tests of the ink inotion oftheinventionhave led to the surprising result" that the ink distribution obtained-is; not onlyas good as, but is better than that obtained with an ink' rnbtion with comparablenumber of cuts but difiering in that theroller- 34, or corresponding roller, is gear driven instead of running free. Whilethere'is'considerable. question as toflthe precise {13350118 for this improvemerit, there is noquestion as to the fact of the-improvement, since the ink distribution characteristics havebeen tested byprinting a;;uni;form half tone screen formation and then observing =the variation in tone density-inthe printing. The elimination-of periodic waves of greater and less density printing, whenvusing the inkm'otion of the invention, is very striking. t

Observations of the roller :speeds have produced-some very interesting results. In the installation tested, the driven rollers-or dru'ms operated without gain, sot-hat the peripheral speeds ofldrums 2!) and- 23 were-equal. The peripheral speed of these rollers'and speed of the idle hard surfaced roller 34' were measured under a variety of ink conditions and; over, a;rangeef -about 300-900 feet per minute peripheral speed. -Under actual printing conditions, a slippage'of-about' 9% :wasbb'se'rved, the relationship between roller speeds being apparently linear. The results obtained are summarized inth'e following table: 1

e' i-ipfiage in feet per minute, this "being the-ditference between column 2 and column 1, and the fourth column expresses this slippage as a percentage figure. It will be observed that the slippage appears to increase as the speed of roller 34 is increased from 240-245 feet per minute to 506-508 feet per minute and then decreases at the higher speed of 765 feet per minute. It will also be observed that the percentage of slip varies significantly between observations No. l and No. 5 at approximately the same speeds and also between observations No. 2 and No.4 'at substantia'lly the same speed. The=average percentage ofslip was about 9%. It is apparent that there is an automatic adjustment of slippage, which is not "a-sirnple function of drive speed and whichvaries markedly even though the ink feed and other operating conditions are maintained constant so far as possible. In view of the demonstrated improvement in ink distribution which was obtained, and in view of the demonstrated slippage and variation in slippagewhich wereobserved, it has been concluded that the floating. drive of :theintermediate hard roller .34 produces automatic variation in speed of this roller with corresponding variation injthe slippage at the cuts, which variation works in such a di- 'r'e'ction as to compensate automatically forffiuctuations in thickness of ink film and to vary the slippage in .a man her 'to reduce" suchffluctuations.

"It not being. practical to varythe ink supplied under actual printing conditions,further series of tests wererun to"determine the effect of ink film thickness on the drive 'conditionsat a single cut. The results ofonc such set. of observations are set forth inthe'fdllowing table:

Second series FtZ/Mlrl. --Ft.YMin.' Ft/Min. 1 Percent 34 20 Sl pDMe' :Slippage In'rnaking the observations summarizedin this.table,..the 'conditionswere'the same as'described above, withthe enceptionthat the rubber roller 35 was. removed. The effect of'this, of course, was to increas cthequantity .of ink on 'the intermediate hard surfaced roller 34. It-will beno'ted thatthe percent of slippage .increasedquite ,significantly an'd'that'the variation'ofslippage with speedis very much reduced. The indicationris.that underaactual printing conditions, the ink film has a tendency-to vary in thickness with vspeed of operationmand. also with I other factorseven though'the speed remains constant, to such. an extent that'the drive torqueis markedly affected. ,It will be notedthat thespeeds of rotation in the secondrseries of observations are somewhat'ditferentfrlom those in the .first series, although not significantly so. This results from .the "factthatthe pressspeed was established accordingto the reading of the press tachometer, a less accurate instrument than the tachometers usedin making the observations.

Athird series of readings were taken withtheroller 35 replaced-and the lower roller "33 removed, itheresiult being "thatthe'cyli'nder 34 and following elements ran-substantially dry. The following results 'wereobtained:

T hird series FtJMin. FtJMln. "FM/Min. Percent 34 :20 rslippage 'Sllppage It will be observed that the slippage is markedly reduced, a's' rni'ght be expected, butalso that a rather anomalous effeet is obtained, in that the percent of slippage at the inter-. mediate speed is decreased by comparison with the slippage at high and low speeds, the reverse of what was found in the observations of the first series. It may be inferred that difference in thickness of ink film at a cut not only affects the percent of slippage at any given speed, but also affects in a very marked way the variation in slippage with variation in speed, going so far as to reverse the curve.

A fourth series of readings were made under the same conditions as the third series, but with the tachometer reading the speed of cylinder 23 instead of cylinder 20:

Fourth series As might be expected, the indicated percentage of slippage at the various speeds was approximately the same as in the 7 third series, in most cases, but exhibited a variation of about the same order of magnitude as observed at corresponding speeds in the other series. It is 'of interest to note that at the higher speed the slippage is reversed, indicating that the roller or cylinder 34 was travelling at a higher peripheral speed than the driving roller 23. This result, while apparently anomalous, is not inconsistent with the theory, so far as known, since variation in flat may change the drive ratio between a hard surfaced and soft surfaced roller so that a difference in flat at the cut 34-35 and the flat at the cut 35-43 could well result in negative slip, as indicated.

While a great deal of theorizing has been done on the variation of drive ratio between hard surfaced and soft surfaced rollers, and it is generally accepted that in friction drives the drive must be from soft to hard cylinder instead of vice versa, it is apparent that under actual press operating conditions, where the ink motion rollers are covered with a film of ink there is no simple explanation or formula which accounts for the observed phenomena. It appears, merely, as stated above, that the thickness of ink film influences the slippage and that the slippage variation is in a direction to regularize or even out the distribution of the ink. v

The compactness of the structure is quite striking, and permits an advantageous rearrangement of the ink rail with respect to the first drum or cylinder of the train. It will be observed that the ink rail is positioned directly below the first drum 20 and that it is mounted for a generally vertical pivotal movement toward and away from that drum. As a result, ink mist or spray from the various cuts is caught by the drums and rollers themselves, avoiding loss of ink and dirtying of adjacent mechanisms. The normal direction of rotation of the printing unit is clockwise as to the right hand plate cylinder and counter clockwise as to the left hand plate cylinder of the unit, and the direction of rotation of the driven ink drums associated with these cylinders is the same. It will be noted that ink mist emerging from the cut 34-20 is boxed in by the remaining rollers and cylinders so that it will not leave the ink motion. If the unit is reversed, the same effect is obtained, and, in fact, a tangent plane through any flat will lead to the surface of one of the rollers or cylinders of the ink motion, except for the cut 34-35. At this point, however, the ink film has been quite well distributed, so that the tendency toward ink mist formation is very much reduced. Although it would be difficult to demonstrate in any quantitative way, it appears that the ink mist produced at this cut (or at the cut 3334 when the unit is reversed) is reduced by permitting the cylinder 34 to run free.

Whatis claimed is: I,

1'. In a printing machine ink motion,and in combination, first and second axially reciprocable ink drums, gearing and drive mechanism for rotatably drivingand axially reciprocating the said drums, means for supplying ink to the first said drum and means for taking-ink from the second said drum for inking a printing cylinder, anink transfer mechanism between the two said drums comprising first and second soft surfaced rollers contacting the respective drums and a freely rotatable hard surfaced roller contacting the two said soft surfaced rollers.

2. In a printing machine ink motion, and in combination, first and second axially reciprocable ink drums, gearing and drive mechanism for rotatably driving and axially reciprocating the said drums, means'forv supplying'ink to the first said drum and means for taking ink from the second said drum for inking a printing cylinder, an ink transfer mechanism between the two said drums comprising first and second soft surfaced rollers contacting the respective drums and a freely rotatable but axially fixed hard surfaced roller contacting the two said soft surfaced rollers.

3. In a printing machine ink motion, and in combination, first and second axially reciprocable ink drums, gearing and drive mechanism for rotatably driving and axially reciprocating the said drums, means for supplying ink to the first said drum and means for taking ink from the second said drum for inkinga printing cylinder, an ink transfer mechanism between the two said drums comprising first and second soft surfaced rollers contacting the respective drums, a freely rotatable but axially fixed hard surfaced roller contacting the two said soft surfaced rollers, and adjustable supports for soft surfaced rollers whereby the axial distance thereof from the drums and intermediate roller may be regulated.

4. In a printing machine ink motion, and in combination, first and second axially reciprocable ink drums, gearing and drive mechanism for rotatably driving and axially reciprocating the said drums, means for supplying ink to the first said drum and means for taking ink from the second said drum for inking a printing cylinder, an ink transfer mechanism between the two said drums comprising first and second soft surfaced rollers contacting the respective drums and a freely rotatable hard surfaced roller contacting the two said soft surfaced rollers, the said rollers being arranged in mutual unstable driving relation for driving the said hard surfaced roller with a substantial and variable slippage.

5. In a printing machine ink motion, and in combination, first and second axially reciprocable ink drums, gearing and drive mechanism for rotatably driving and axially reciprocating the said drums, means for supplying ink to the first said drum and means for taking ink from the second said drum for inking a printing cylinder, an ink transfer mechanism between the two said drums comprising first and second soft surfaced rollers contacting the respective drumsand a freely rotatable hard surfaced roller contacting the two said soft surfaced rollers, the said rollers being arranged in mutual unstable driving relation for automatically varying the slippage ,ofthe hard surfaced roller, whereby variation in ink film thereon causes compensating variation in slippage.

6. In a printing machine ink motion, and in combination, first and second reciprocable ink drums, drive gearing therefor comprising a drive gear fixed to each drum, an intermediate idle gear in mesh with the said drive gears and mechanism for axially reciprocating the said drums, an axially fixed freely rotatable hard surfaced roller between the said drums and offset from their common axial plane, and soft surfaced rollers in ink transferring and driving relationship to the said drums and hard surfaced roller. 7

7, In Epfi'ntin'g *inaehine ink motion, andin combination, hrstflnd second reciproca'ble ink drums, drive gear ingmentor comprising 'a drive gear fixed to each. drum, an intermediate idle gear in mesh with the said drive gearmnumone side thereof, andmechanism for a'xially reeiprocatin'g-the said-drums, an axially'fi xed 'freelyrotatable hardsurfaced roller between the said drumsand also olfset from their common axial plane, and soft S'u'ffacdiollr's in -ink transferring and driving relation'ship tothesaid drums and hard surfaced roller, the said idle gear being supported with part of it in alignment with the-shaft of thesaid hard' surf-aced roller.

8. Ina printing machineinkmmion, and in combinatibn, andisecond reciproeable ink dnims, drive gearing-therefor eom risin'ga drivegear fixed to each drum, anintermediate idle gear in mesh with the said drive gears and toone side thereof, and mechanism for axially reciprocating the :said drums, an axially fixed freely rotatablehardsurfaced roller between the'said drums and offsetfromtheir common axial plane onthe side toward saididl'e gear, qs'oft surfaced rollers in ink transferring and driving relationship to the said drums and hard surfaced roller, and-an ink rail'supplying ink to the first said drum along a line substantially in the common axial plane of the said drums.

References-Citedin'thc file of this patent UNITEDSTATES PATENTS 396,612 Scott Jan. 22, 1889 2,163,374 Crafts June 20, 1939 2,378,926 \Huck June 26, 1945 2,448,975 Harrold Sept. 7, 1948 2,581,687 'McWhoftef Jan. 8, 1952

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