US3272122A - Method of adjusting a foreshortened impression roller - Google Patents

Description

p 3, 1966 A. c. BEHRINGER N 3,272,122

METHOD OF ADJUSTING A FORESHORTENED IMPRESSION ROLLER Filed March 21, 1961 5 Sheets$heet l INVENTOR. ALFRED C. BEHRINGER BY 4 12 ,EZQ ZMM y his ATTORNEYS ROLLER Sept. 13, 1966 A. c. BEHRINGER METHOD OF ADJUSTING A FORESHORTENED IMPRESSION 5 Sheets-Sheet 2 Filed March 21, 1961 gm OUT OF LEVEL FIG. 4B.

INVENTOR. ALFRED C. BEHRINGER his AT TOR/V11 Y5 A. C. BEHRINGER 5 Km H m N N P. E w m VH2 A T MB A D .s w h 6 w H A M METHOD OF ADJUSTING A FGRESHORTENED IMPRESSION ROLLER Filed March 21, 1961 ROLLER Sept. 13, 1966 A. c. BEHRINGER METHOD OF ADJUSTING A FORESHORTENE'D IMPRESSION 5 Sheets-Sheet 4 Filed March 21, 1961 INVENTOR. ALF'RED C. BEHRINGER his ATTORNEYS Sept. 13, 1966 METHOD OF ADJUSTING A FORESHORTENED IMPRESSION ROLLER Filed March 21, 1961 A. c. BEHRINGER 3,272,122

5 Sheets-Sheet 5 J? a 72 4 L I 1" 66 i5 g a 67 69 Q 6 F/G 7 65 I ll 65 his ATTORNEYS United States Patent 3,272,122 METHOD OF ADJUSTING A FORESHORTENED IMPRESSION ROLLER Alfred C. Behringer, Cupsaw Lake, Ringwood, N.J., assignor to Publication Corporation, New York, N.Y., a corporation of New York Filed Mar. 21, 1961, Ser. No. 97,202 1 Claim. (Cl. 101-426) This invention relates to improvements in printing presses, and more particularly to an improved rotogravure printing press and to a method of adjusting the impression roller of a rotogravure printing press relative to the printing cylinder when an impression roller of less than full length is used.

In conventional rotogravure printing presses, the matter to be printed is etched in the surface of a printing cylinder which rotates on a fixed axis partly immersed in an ink reservoir. The excess ink is wiped from the surface of the printing cylinder by a doctor blade, and the inked impressions are printed on a paper web fed between the printing cylinder and a rotatable impression roller in tangential relationship to the printing cylinder. The impression cylinder is mounted between a pair of springloaded supports which are separately adjustable in the side frames of the printing press to permit the impression roller to be bodily translated toward and away from the printing cylinder or angularly orientated with respect to the printing cylinder. For convenience, especially in large presses, these supports are driven by a motor through clutch means so that the end supports for the impression roller can be moved separately or in synchronism. When the impression roller is in operative tangential relationship with the printing cylinder, the springs which act on the end supports determine the pressure engagement between the impression roller and the printing cylinder.

The initial adjustments of the impression roller relative to the printing cylinder to obtain the desired uniform pressure between them is critical in high quality printing. It involves time-consuming adjustments in the relative positions of the end supports with the drive clutch disengaged, adjustment of the springs which act on the end supports, and the setting of limit switches which determine the operative position of the impression roller and the throw-out pressure of the impression roller. Once these initial adjustments have been made, they are preferably retained until further adjustments become necessary.

From time to time, it becomes necessary to convert the press to print on a narrower web of paper from less than the full length of the printing cylinder. In such instances, one end of the printing cylinder is not used, and a shorter impression roller is employed so as not to transfer ink from the printing cylinder to the impression roller in the non-printing areas. In a typical example, it may be desirable to print from three-quarters of the full length of the printing cylinder, in which case, a foreshortened impression roller of three-quarters length is used. When it has been necessary to use impression rollers of less than full length, pressmen have encountered great difficulty in obtaining uniform pressure between the impression roller and the printing cylinder throughout the length of the bite between the cylinders. This results from the fact that the operative position of the impression roller is determined by the pressure engagement between the impression roller and the printing cylinder. More specifically, when the impression roller is being moved by power into operative position with respect to the printing cylinder, the end supports move toward the printing cylinder until the desired spring pressure at one end of the press is obtained, at which point a limit switch stops the further movement of the end supports. However, because the shortened end of the im- 3,272,122 Patented Sept. 13, 1966 pression roller oifers less resistance to the spring, the corresponding end support will travel a greater distance than the opposite end support before suflicient spring pressure is built up to stop the motion of the end support, thereby tilting the axis of the impression roller downwardly at the short end of the impression roller, producing excessively high pressure between the impression roller and the printing cylinder at the short end and insufficient pressure between the printing cylinder and the impression roller at the opposite end. Needless to say, this produces a much heavier impression and excessive wear at the foreshortened end of the impression roller and a lighter impression at the opposite end.

In the past, this non-uniform pressure between the foreshortened impression roller and the printing cylinder has been compensated for in various ways. In some instances, a ring or band several inches wide is permitted to remain on the foreshortened end of the impression roller to provide increased resistance to the spring which acts on the corresponding end support for the impression roller, thereby minimizing to some extent the tendency of the axis of the impression roller to assume a tilted position relative to the axis of the printing cylinder. Obviously, however, this ring or band will not provide the same resistance for the spring as a full length impression roller, so that this method by itself is not a satisfactory solution to the problem.

Another method of attempting to improve the uniformity of the impression when .a shorter impression roller is used, which can be used by itself or in conjunction with the ring or band described above, is to change the relative positions of the end supports for the impression rollers by declutching one of the end supports from the drive mot-or and lowering the end support for the impression roller opposite the foreshortened end in relation to the end support at the foreshortened end in order to apply additional pressure to the impression roller at the end opposite the foreshortened end. The disadvantage of this method, however, is that it is virtually a hit-and-miss proposition, since there is no way of determining the amount of reverse tilt that will be necessary in order to produce a parallel relationship when the impression roller is restored to pressure engagement with the printing cylinder. Also, this type of compensation, while improving uniformity, makes for greater than desired pressure, resulting in greater heat and wear. In addition, when a full length impression roller is substituted for the short length impression roller, it will be necessary to readjust the impression roller for uniformity.

The object of the present invention is to provide a simple solution to this problem of adjusting a foreshortened impression roller relative to the printing cylinder to obtain uniform pressure engagement throughout the length of the bite therebetween without losing resistance for the spring on the foreshortened end of the impresion roller. This is accomplished in the present invention by intercepting the end support for the impression roller at the foreshortened end at approximately the position which it would occupy with a properly adjusted impresion roller of full length. The particular interceptor used can be improvised by the pressman, such as, for example, a shim of the desired thickness can be interposed between the movable end support and a part of the frame, or preferably, the interceptor can be in the form of an adjustable stop built into the machine to produce this result.

The present invention provides a simple solution to the problem of obtaining a proper adjustment of a foreshortened impression roller relative to the printing cylinder so as to produce uniform pressure engagement therebetween throughout the entire length of the impression roller. The solution is far superior to the conventional practices heretofore in use without requiring disengagement of the clutch, relative positioning of the end supports for the impression roller, or resetting of the springs.

For a complete understanding of the present invention, reference can be made to the detailed description which follows, and to the accompanying drawings, in which:

FIGURE 1A is a front view of a printing press equipped with a full length impression roller;

FIGURE 1B is a side elevation of the printing press shown in FIGURE 1A, showing the spring compression indicators;

FIGURE 2A is a view similar to FIGURE 1A showing in somewhat exaggerated fashion the condition of the press when equipped with a foreshortened impression roller without benefit of the present invention;

FIGURE 2B is a side elevation of the press showing the change in the readings of the spring compression indicators when the press is equipped with a foreshortened impression roller;

FIGURE 3A is a view similar to FIGURE 2A illustrating the conventional method of compensating for the loss of uniformity when a foreshortened impression roller is used;

FIGURE 3B is a side elevation of the view shown in FIGURE 3A;

FIGURE 4A is a view similar to FIGURE 2A, except that the position of the end support for the impression roller at the foreshortened end has been intercepted in accordance with the present invention;

FIGURE 4B is a side elevation of FIGURE 4A, showing an interceptor shim in place;

FIGURE 5 is an enlarged view similar to FIGURE 4B showing certain of the operative mechanism in crosssection and a screw type inteceptor;

FIGURE 6 is a view generally similar to FIGURE 4B showing the dial indicating apparatus in more detail and the preferred form of interceptor;

FIGURE 7 is a cross-sectional view taken along a plane 7-7 of FIGURE 6, looking in the direction of the arrows; and

FIGURE 8 is a cross-sectional view taken along a plane 88 of FIGURE 7, looking in the direction of the arrows.

A conventional rotogravure printing press, as shown in FIGURES 1A and 1B, comprises a printing cylinder 1, an impression roller 2, and an impression back-up roller 3 for the impression roller. The printing cylinder 1 is supported for rotation in bearings mounted in the side frames 4 and 5 of the press. The impression roller and the backup roller are supported for rotation between slide blocks or end supports 6, one of which is vertically adjustable in the side frame 4 and the other of which is vertically adjustable in the side frame 5.

The printing cyclinder carries an etched printing surface to be printed. The printing cylinder rotates partly immersed in an ink reservoir (not shown), and excess ink is wiped from the printing cylinder by a doctor blade before the printing surface comes into printing contact with a paper web fed between the printing cylinder and impression roller.

The slide blocks 6 are movable in their respective side frames to translate the impression and back-up rollers toward and away from the printing cylinder under the power of a motor 7 supported from a cross-beam 8 of the frame of the press. A shaft 9, supported for rotation between the side frames of the machine above the impression and back-up rollers, is driven by the motor 7 through a gear transmission system 10. One end of the shaft 9 transmits motion through a coupling 11 to raise or lower the slide block 6 guided for movement in the side frame 4, and the other end of the shaft 9 transmits motion through a clutch 12 to raise or lower the slide block guided for movement in the side frame 5. The clutch 12 is engaged and disengaged by the actuation of a clutch lever 13. When the clutch 12 is engaged, the

motor imparts motion to both slide blocks 6 in synchronism. When the clutch is disengaged, the motor remains operatively connected to the slide block accommodated for movement in the side frame 4, but it is disconnected from the slide block accommodated for movement in the frame 5. It is apparent that by disengaging the clutch the slide blocks can be adjusted relative to each other to change the angle of the axis of rotation of the impression roller.

The means for translating the rotational movement of the shaft 9 into vertical movement of one of the slide blocks 6 is shown in FIGURE 5. Although FIGURE 5 shows only the mechanism for raising and lowering the slide block of the side frame 5, the slide block of the side frame 4 is raised and lowered by a similar mechanism on the opposite side of the press. This mechanism includes a worm 15 driven from the shaft 9 through the clutch 12, a rotatable pinion 16 supported between upper and lower stationary bearings 17 and 18, respectively, an internally threaded tubular element 19 connected by vertical splines 20 to the inner periphery of the worm gear 16, and a vertically movable, non-rotatable threaded shaft 21 threadably coupled to the tubular element 19 and supporting the slide block 6 at its lower end. The lower end of the threaded shaft 21 passes through a retaining plate 23 carried by the slide block 6.

The upper bearing 17 for the worm gear 16 is held in place by a stationary collar 24 affixed by bolts 25 to the upper end of the gear housing 26. The gear housing 26, in turn, is fixed to the side frame 5 of the press. The lower bearing 18 is held in place by a retaining plate 27 connected by bolts 28 to the underside of the gear housing.

The rotation of the worm 15 by the motor 7 imparts rotation to the worm gear 16 and the internally threaded element 19 splined to the worm gear, thereby moving the threaded shaft 21 in an axial direction to raise or lower the slide block 6, depending on the direction of rotation of the worm.

The slide blocks 6 are each accommodated between side guides 29 of the respective side frame. As explained above, the slide block carries the bearings for both the impression roller and the back-up roller, so that these rollers can be raised or lowered relative to the printing cylinder by raising or lowering the slide blocks. When the slide blocks are lowered to bring the impression roller into operative relationship with the printing cylinder, the desired pressure engagement between the printing cylinder and impression roller is obtained by compressing springs which act on the slide blocks 6. Toward this end, as shown in FIGURE 5, the slide block is acted on by a spring 30. The upper end of the spring 30 is received within an annular sleeve 31 of the respective side frame and acts against a rotatable spring backing element 32. The lower end of the spring 30 acts against a washer 33 interposed between the spring and a spring loading nut 34. The :loading nut 34 is threaded to a hearing retaining element 35 which is in telescoping relationship with the upper end of the threaded element 19, the bearing 36 being interposed therebetween to support the upper end of the threaded element 19 for rotation. The element 35 is connected to the collar 24 by vertical splines 36a.

When the slide block 6 is lowered to bring the impression roller into engagement with the printing cylinder, the continued rotation of the threaded element 19 causes it to move upwardly on the threaded shaft 21 against the action of the spring 30, since the slide block 6 and threaded shaft 21 cannot move downwardly any further. The threaded element 19 moves upwardly relative to the worm gear 16 because of the splined connection therebetween, and this upward movement lifts the element 35 and the loading nut 34, thereby compressing the spring 30 to increase the spring force exerted on the slide block, as well as to increase the pressure engagement between the printing cylinder and impression roller. A sleeve 38 surrounds the spring 30, but this sleeve moves relatively to and is guided by the spring backing element 32.

The force of the spring 30 on the slide block 6 can be varied by the rotation of the loading nut 34. Indicators 39 and 40 show the load of the springs for the slide blocks 6 accommodated in the side frames 4 and 5, respectively. The position of the loading nut is translated into a reading on the respective indicator by the mechanism shown in FIGURE 6. Toward this end, a finger 41 of a pivotal lever 42 is urged into contact with the underside of the loading nut 34 associated with the slide block of the side frame 5 by a spring 43. The position of the loading nut is translated into a reading on the dial indicator 40 through a turnbuckle link 44, an arm 45, a pivotal gear segment 46 moved by the arm 45, a gear 47 on a shaft 48 and mes-hing with the gear segment 46, a gear 49 on shaft 48, and gears 50 and 51 to the dial indicator 40. The spring force in thousands is read on the face of the gear 49 through an aperture 52 in the dial, and the force in hundreds is read by the position of the indicator 40 relative to the dial.

Similarly, the position of the loading nut associated with the side frame 4 is translated into a reading on the indicator 39 by a linkage generally designated by the mechanism 53 in FIGURE 6.

The shaft 48 carries two cams, one of which is capable of operating a limit switch 54 through a cam follower linkage 55 and the other of which is capable of operating a limit switch 56 through a cam follower linkage 57. The limit switch 54 operates to stop the downward movement of the slide block 6 at the desired compression of the spring 30, thereby to obtain the desired pressure engagement between the impression roller and the printing cylinder. The limit switch 56, on the other hand, operates in response to an overload spring force to raise the slide block and relieve pressure between the impression roller and the printing cylinder.

The rotogravure printing press, as described above is conventional, and the explanation has been set forth in this detail only to facilitate the understanding of the present invention.

FIGURE 1A shows a full length impression roller 2 of diameter al which has been properly adjusted relative to the printing cylinder 1 to obtain uniform flats P and P at opposite ends. If the slide blocks 6 which support the impression roller are then raised, a foreshortened impression roller of diameter d substituted for the full length impression roller and the slide blocks then lowered automatically by the motor 7 to the position determined by the limit switch 54, the slide block in the side frame 5 will travel further before the pre-set spring force is built up, causing the axis of the impression roller to tilt in the manner shown in FIGURE 2A. In this tilted condition, the flat P at the foreshortened end will be substantially greater than the flat P at the opposite end. This not only results in a heavier impression at the fore shortened end of the impression cylinder than at the opposite end, but results in higher heat and wear at the foreshortened end, all of which are detrimental to proper functioning of the press.

As explained above, the conventional methods of compensating for this non-uniformity of impression have been to leave a ring or band (not shown) on the impression roller spaced apart from the foreshortened end, and, as represented in FIGURE 3A, to tilt the impression and backup rollers reversely to the tilt shown in FIGURE 2A. This is accomplished by raising the impression roll above the printing cylinder, disengaging the clutch 12, lowering the slide block of the side frame 4 relative to the slide block of the side frame 5 to impart the opposite tilt, and then restoring the impression roller into operative position relative to the printing cylinder. As explained above, both of these methods are unsatisfactory, the former because it only decreases the non-uniformity of the printing impression, and the latter because it is a hit-and-rniss proposition, and results in excessive local pressure between the printing cylinder and the impression roller.

According to the present invention, as illustrated in FIGURE 4B, a uniform impression can be obtained between a foreshortened impression roller and the printing cylinder throughout the length of the impression roller without disengaging the clutch 12, resetting the springs 30 or moving the slide blocks relative to each other by intercepting the slide block at the aforeshortened end of the impression roller as it is being lowered to opera-r tive position, thereby insuring that it stops at the same position that it would occupy with a properly adjusted impression roller of full length. The interceptor then provides the necessary backing to permit the spring 30 to be compressed to the force necessary to actuate the limit switch 54 and stop the motor 7, with the result that the desired pressure engagement is obtained between the printing and impression cylinders without tilting the axis of rotation of the printing cylinder.

Although there are various ways of accomplishing this result, one method is to interpose a shim 60 (see FIG- URE 4B) of proper height between the base of the slide block 6 and the shelf or ledge 61 of the frame. If the diameter d, of the full length impression roller is the same as the diameter d of the foreshortened impression roller, the height x of the shim 60 should be equal to the space a (see FIGURE 1B) between the base of the slide block and the ledge or shelf 61 of the frame of a properly adjusted full length impression roller. If the diameters are different, the difference should be taken into consideration in selecting the height of the shim. For example, if the diameter d of the full length impression roller is greater than the diameter d of the foreshortened impression roller, the height x of the shim is determined by the relationship On the other hand, if the diameter d of the full length impression roller is less than the diameter d of the foreshortened impression roller, the height of the shim is determined by the relationship In lieu of a shim, the interceptor can take the form of an adjustable screw 62 threaded into the top of the shelf 61 or into the bottom of the slide block 6, the former being shown in FIGURE 5.

A preferred form of interceptor is shown in FIGURES 6 to 8 of the drawings. This interceptor comprises a movable stop 63 carried by the slide block 6 and adjusted by a knob 64. The knob carries a dial 65 which moves relative to a stationary indicator 66 to facilitate adjustment of the stop. The knob rotates in bearings 67 of the slide block, and the knob carries a worm 68 which meshes with a pinion 69. The pinion is rotatably mounted in fixed bearings 70 within the slide block, and the pinion is internally threaded to displace the threaded stop 63 longitudinally to the desired position of adjustment indicated by the dial. A coverplate 71 holds the pinion 69 within a recess of the slide block 6, and the engagement of a key of the coverplate with a vertical groove 72 in the stop 63 prevents rotation of the stop.

In a press in which the springs 30 on both sides are initially balanced and the indicators are pre-set to show the balance, the setting of the interceptor can be on a trial-and-error basis, and the pressman will be able to ascertain that uniformity in pressure between the impression roller and the printing cylinder is obtained when the indicators 39 and 40 have identical readings. Moreover, with the preferred form of interceptor shown in FIGURES 6 to 8, it is possible to obtain uniform pressure between the impression roller and the printing cylinder without initial calculation by the adjustment of the knob 64d?0 obtain a uniform reading on the indicators 39 an The interceptors of the present invention not only stop the slide block at the foreshortened end of the impression roller in the position it would occupy with a properly adjusted impression roller of full length, providing the necessary resistance for the spring 30, but prevents the tilting of the axis of rotation of the impression roller depicted in FIGURE 2A. As a result, the desired uniform pressure is obtained throughout the length of the bite 'between the printing cylinder and impression roller without any adjustment of the springs 30, or any need to disengage the clutch 12 and move the slide blocks 6 relative to each other. Thus, a full length impression roller can be readily substituted for the foreshortened impression roller without readjustment of the press simply by removing the interceptor.

The interceptors of the present invention are preferably provided at both sides of the press because at times it may be desirable to foreshortcn the full length roller at one end or the other. In addition, the provision of interceptors at both sides of the press may be useful in obtaining improved printing and better register under certain conditions, such as for example, where it is desired to decrease the spring load on the impression roller without changing the initial adjustment of the springs and setting of the limit switches.

The invention is shown and described in preferred forms and by way of example only, and various modifications and variations can be made therein without departing from the spirit of the invention. The invention, therefore, is not to be limited to any particular form or embodiment, except insofar as limitations are expressly specified in the appended claim.

I claim:

The method of adjusting a roll short at one end relative to a full length cylinder of a printing press so that the roll acts uniformly against a length of the cylinder at one end of the cylinder, said printing press including a pair of end supports for the roll, common drive means for imparting movement to both of said end supports in unison to bring them into engagement with the cylinder, means controlled by said drive means for building up predetermined forces on both said end supports after the roll is brought into engagement with said cylinder, and means for stopping said common drive means when predetermined forces have been built up on both of said end supports to provide uniform pressure engagement between said cylinder and a roll which engages the full length of said cylinder, said method comprising the steps of moving the end supports by said common drive means to bring the short roll into operative engagement with the cylinder until said common drive means is stopped by the application of the predetermined forces on the end sup ports, and intercepting by interposing a stop in its path of travel the end support at the short end of the roll at the position which the end support would occupy if it carried a full length roll corrected for any difference between the diameter of the said full length and the short roll while permitting the common drive means to operate until the predetermined forces have been built up on both end supports, the full length end of the short roll moving to a position relative to the cylinder determined by the predetermined force transmitted to the respective end support and the short end of the short roll moving to and no further than the position determined by the said stop, thereby obtaining uniform pressure engagement between the short roll and the cylinder.

References Cited by the Examiner UNITED STATES PATENTS 240,282 4/ 1881 Stevens 308-59 252,705 1/1882 Stevens 30859 X 466,251 12/1891 Moore 308-59 X 1,261,903 4/1918 Brown 10123 2,076,241 4/ 1937 Luehrs 101247 2,118,965 5/1938 Buttner 101247 2,202,785 7/ 1940 Crafts. 2,212,820 8/1940 Barber 101-153 ROBERT E. PULFREY, Primary Examiner.

R. A. LEIGHEY, Examiner.

R. T. CUNNINGHAM, EDGAR S. BURR,

Assistant Examiners.

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