US 3261288 A
Abstract available in
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Description (OCR text may contain errors)
July 19, 1966 H, R, DlcKERsON 3,261,288
ANTISMEAR JACKET FOR TRANSFER DRUM Filed June 8, 1964 2 Sheets-Sheet 1 1 July 19, 1966 H, R, DlcKERsoN 3,261,288
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United States Patent 3,261,288 ANTISMEAR JACKET FOR TRANSFER DRUM Henry R. Dickerson, 3414 Grace Road, Kalamazoo Township, Kalamazoo County, Mich. Filed June 8, 1964, Ser. No. 373,430 5 Claims. (Cl. 101-420) This invention relates in general to an apparatus for preventing smearing on a freshly printed sheet passing through a printing machine and, more particularly, to a type of such apparatus adapted for use on a transfer drum or cylinder between two units of printing cylinders in a rotary sheet-fed offset press.
It has ,been common knowledge in the printing industry for many years that the smearing of freshly printed sheets has been a serious problem. In fact, it still produces staggering losses in some types of machines and on certain types of jobs. For example, this problem has been particularly acute in multicolor, rotary lsheet-fed offset presses where the 'freshly printed surface must engage the peripheral surface of the transfer drum as the printed sheet is moved from one unit of printing cylinders to the next. Even where some effort is made to minimize such smearing, considerable losses are still experienced and, moreover, the nal product is often smeared anyway. Many attempts have been made to overcome this smearing problem on -transfer drums or the like, but no satisfactory solution has been developed, insofar as I am aware.
For example, :attempts have been made to use air pressure to hold the printed surface away from the transfer drum during the transfer operation. However, it is very dicult lto control sheet material while air is being applied thereto, and it can result in movement of the sheet which not only creates smearing but also tends to throw the sheet out of register for the following printing operations. Moreover, it requires a very special type of transfer drum which must be installed upon the machine at a very high cost.
In another -attempt to solve this problem, printers have applied to the surface of the transfer drum strips of materials which are designed to engage unprinted portions of the printed sheet for the particular printing jo=b being run at any given time. However, the obvious difficulty with this method is that the unprinted areas are usually in a different place for each job. Accordingly, these spacing strips must be changed for each job at a very high cost in time and materials. In most multicolor offset printing operations, a few hours of down time for the purpose of providing :and/ or locating spacing elements on the transfer drum would absorb la substantial part of the profit in the job.
It occasionally happens that a piece of material upon which printing is being applied by a rotary sheet-fed press is either defective or becomes bent or folded during the printing operation so that it produces an oversize thickness in :a particular reg-ion which will pass through the printing press unless it is promptly detected .and removed. Thus, it is important that any type of antismear jacket used on a rotary sheet-fed printing press must be capable of receiving -an oversize thickness without injury to the jacket and without upsetting the normal operation of the press. Insofar las I am aware, many of the antismear devices which have been previously provided for the transfer drum on a rotary sheet-fed offset press would be adversely affected by the movement of an oversized thickness of material between the transfer drum the impression cylinder.
While the invention will be described herein as it applies to a multi-unit or multicolor rotary sheet-fed offset printing press, it will be recognized that the principles of the invention can be adapted for use in a at ICC bed printing press where the sheet of printed materials must move across a surface after it has been printed and, moreover, could be applied to other types of printing presses where the freshly printed sheet must move with its printed surface adjacent another surface whereby smearing may occur.
Accordingly, a primary object of this invention has been the provision of an antismear apparatus or jacket for preventing the smearing of a freshly printed sheet as it passes through a printing machine and particularly to a type of jacket which is adapted for mounting upon the transfer drum between two units of printing cylinders in a rotary sheet-fed offset printing press.
A further object of this invention has been the provision of an antismear jacket, as aforesaid, which can ibe mounted upon the transfer drum, for example, of an existing offset press without materially modifying the structure of the transfer drum or press and without altering its operation; and wherein said antismear jacket can be installed upon the transfer drum of the press without requiring a major shutdown of the press and, therefore, without materially interfering with operating schedules of said press.
A further object of this invention has been the provision of an antismear jacket, as aforesaid, which is arranged to engage selected parts of the freshly printed side of a printed sheet as it is moved by a transfer drum, the contact with the printed side being along narrow lines or a series of points along such lines so that `smearing is generally avoided or is -at least maintained at an absolute minimum commensurate with supporting the printed sheet with the necessary firmness to move it from one unit of printing cylinders to the next; and wherein the line of contact or the line of points of contact or multiples of such lines can be quickly changed as, for example, in several minutes, whereby the transfer drum can be adjusted Ifor antismear operation with respect to a different printing job in less time than -it requires to prepare the remainder of the machine for the new printing job.
A further object of this invention has been the provision of an antismear jacket, as aforesaid, which is easily adapted to Ia variety of different installations and uses, which can be operated by any person capable of operating a printing press, which can be installed by any person capable of maintaining a printing press, which requires little or no maintenance, which is not readily susceptible to damage, which, particularly in terms of the initial cost of the printing press, adds an almost negligible amount to the cost of the press and is capable of paying for itself in saved time and reduction of waste in a very short period of time.
Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon reading the following descriptive material and examining the accompanying drawings, in which:
FIGURE 1 is a broken and somewhat schematic, side elevational view of an offset printing press showing one application of the invention.
FIGURE 2 is a transaxial, cross-sectional view of a transfer drum having a pair of antismear jackets mounted thereon.
FIGURE 3 is a broken sectional view taken along the -line III-III in FIGURE 2.
FIGURE 4 is an enlarged fragment of the structure shown in FIGURE 2.
FIGURE 5 is an enlarged sectional view taken along the line V--V in FIGURE 4.
FIGURE 6 is a broken frag-ment of an antismear jacket in its substantially flat position.
FIGURE 7 is a sectional view taken along the line VII-VII in FIGURE 6.
FIGURE 8 is a broken plan view substantially as taken from the line VIII-VIII in FIGURE 4.
FIGURE 9 is a sectional view substantially as taken along the line IX-IX in FIGURE 5.
FIGURE 10 is a transaxial, cross-sectional view of a transfer drum utilizing a single antismear jacket.
FIGURE 11 is a fragment of the jacket appearing in FIGURE 10.
For convenience of illustration, the terms upper, lower and words of similar import will have reference to the antismear jacket or parts thereof, when said jacket is in its substantially flat position, as appearing in FIG- URES 4, 7 and 9. The terms front and rear or leading and trailing will have reference, respectively, to the right and left ends of the antismear jacket or the portions of the drum to which it is attached as appearing in FIGURES 6 and 7. The terms inner, outer and derivatives thereof will have reference to the geometric center of the transfer drum and parts of the antismear jacket, as applied to the transfer drum.
General construction The objects and purposes of the invention, including those set forth above, have been met by providing a plurality of parallel and closely spaced elements and associated parts capable of locating said elements substantially within the same plane, or adjacent a single curved surface. In one preferred embodiment, said elements are mounted upon a substantially tlat sheet of material to form a single jacket or assembly which can be quickly secured upon the peripheral surface of an existing transfer drum, for example.
More specifically, one end of each element is secured to the sheet material substantially along a line near one edge thereof and the opposite ends of said elements are connected to devices for selectively moving said opposite ends between two positions, In one position of an opposite end, the respective element is held snugly against the adjacent surface of the si eet material, particularly when it is mounted upon a transfer drum. In the other position, the element is spaced `a selected distance substantially throughout its length away from the adjacent surface of the sheet material. Each element is connected to a mechanism for resiliently urging the elements into the raised position, and to a device for releasably opposing such urging.
While the specific apparatus disclosed hereinafter with respect to the antismear jacket is designed for use on the transfer drum of a multiunit, rotary sheet-fed offset printing press, it will be recognized that the same principles can be adapted to other types of printing machines. Moreover, while the elements are designed in this particular disclosure for extension around the axis of the transfer drum, it will ybe apparent that, by minor modification, the elements can be arranged for extension lengthwise of the drum and parallel with its axis.
Detailed description The antismear apparatus 1G (FIGURES 2 and 3), which illustrates one embodiment of the invention, is particularly adapted for moun-ting upon the transfer drum 11 of a rotary sheet-fed offset printing press 12, a portion of which is schematically shown in FIGURE 1. Since a transfer drum is usually used between two units of printing cylinders in a multicolor offset printing press, FIGURE 1 discloses similar units 13 and I4 having plate cylinders 16 and 17, blanket cylinders 18 and 19, and impression cylinders 20 and 21, respectively. Generally speaking, the afore-mentioned parts of the offset press 12 may be substantially conventional and, therefore, may be found in a number of existing, offset printing machines, such as those mentioned in my copending patent application Serial No. 300 890, led August 8, 1963, for
@Lees Cil a Printing Machine and Method, now Patent No. 3,172,359.
The transfer drum or cylinder 11 is provided with a pair of parallel wells 24 and 25 which extend lengthwise of the drum on diametrically opposite sides thereof. The wells divide the peripheral surface of the transfer drum into two sheet engaging or transfer surfaces 26 and 27, which extend between the wells 2S and 25 on opposite sides of the drum 11, the circumferential length of each surface being approximately equal to the circumferential length of the unbroken part of the peripheral surface on each of the impression cylinders 20 `and 21. Accordingly, a piece of sheet stock 28 (FIGURES 1 and 3) may be transferred from the impression cylinder 20 to the impression cylinder 21 by the transfer drum i1 and thence, for example, to a discharge device 29 which conveys the printed sheet stock 28 to the discharge end of the printing machine. Additional units of printing cylinders and transfer drums could be provided on both sides of those specifically disclosed.
Since the transfer drum has two transfer surfaces 26 and 27, it can transfer two printed sheets from one unit to the next during each revolution of the transfer drum. Accordingly, a pair of antismear apparatuses 10 and 10a, which may be identical, are mounted upon transfer drum 11. However, since the two antismear apparatuses 10 and 10a may be identical, only one such apparatus will be described and it will be understood that such description also applies to the other antismear apparatus.
As shown in FIGURES 4, 6 and 7, the antismear apparatus 1d is comprised of a base sheet or plate 32 which is preferably as wide as the transfer drum 11 and somewhat longer than the circumferential length of the transfer surface 26. The opposite, circumferential end portions of the base sheet 32 are bent to form flanges 33 and 34 which extend in approximately the same direction inwardly away from the sheet 32 for reception into the wells 24 and 25, respectively. The base sheet 32 may be fabricated from sheet metal and is sufficiently flexible that it can be wrapped around and held snugly against the transfer surface 26 of the drum 11.
The free edge of the flanges 33 (FIGURE 4) is rigidly secured, as by welding, to an elongated, substantially rigid mounting plate 36 which is tightly held against the bottom wall 37 of the well 24 by means, such as the screws 38. An elongated support beam 39 having a substantially L-shaped cross section (FIGURES 4 and 9) is rigidly secured to, and extends lengthwise of, the mounting plate 3e approximately midway between the lengthwise edges thereof.
The flange 34 is tightly held, as shown in FIGURE 4 with respect to the end portion 34a, against a sidewall of the well 25 (FIGURE 2) by means of the elongated gripper pad 42.
The pivot rod 43 is mounted by means of rod supports, one of which is shown at in FIGURE 9, upon the upright flange 45 I.of the beam 39. A plurality of preferably identical and approximately L-shaped levers 47 are pivotally mounted near the apex yof each upon the pivot shaft 43 at closely spaced intervals lengthwise thereof. A ratchet wheel 43 is rigidly secured to the shaft 43 adjacent each lever 47. An L-shaped pawl 49 is pivotally supported upon each lever 47 for engagement with the teeth of one ratchet wheel '43 whereby rotation of said lever 47 with yrespect to said shaft 43 in ia clockwise direction as appearing in `FIGURE 9, or a counter-clockwise direc-tion as appearing in FIGURE 4, is positively prevented. A spring 52 is connected between the pawl 49 .and the upright arm 53 on the lever 47 whereby said p-awl 49 is continuously urged into engagement with the ratchet rwheel 48.
A plurality of elongated, resiliently flexible spacing elements 54 rare pivotally secured at one end of each by a pivot pin `56 (FIGURE 9) to the free end of the upright arm 53 ion a lever 47. A plurality of openings 57 may be `provided in the arm 53 tio adjust the location of the pivot pin 56 in -accordance with the needs of a particular installation The other end of each spacing element S4, which is preferably made of steel, is secured, as by means of the rivets 58, to the base sheet 32 adjacent the liange 34 (FIGURES 6 and 7).
Throughout most of its length, each spacing element 54 is substantially channel shaped (FIGUiRE l3) whereby strength and substantially uniform curvature lengthwise thereof are achieved. However, it will be recognized that other cross-sectional shapes and type-s of material may be used in the elements 54. Thus, the specic shapes and materials mentioned above are for illustrative purposes only. The bottom .side 59 on each element, which is preferably arcuate transversely thereof, is located on the radially outer side thereof to provide a relatively thin line of contact with the surface of the sheet stock 23 (FIGURE 3) supported thereby.
The Iopposite ends 61 and 62 of each spacing element are preferably flattened so that they lie in substantially perpendicular planes. That is, the flattened end l61 of each spacing element 54 is substantially parallel with the base sheet 32 to wh-ich it is secured. The opposite end 62 of each spacing element is flattened so that it is substantially parallel with the at surface lof the arm 53 on a lever 47. Accordingly, each element is able to ex more readily away from the base sheet 32 .adjacent its connection to the base sheet than at any other point lengthwise thereof. This flexion may be encouraged by prebendi-ng the end portions 61 slightly away from the sheet 3-2. Tlhe flat end 62 cccupie-s about the same amount of space occupied by the lever 47 whereby the spacing between adjacent elements 54 `can be held to a minimum, depending largely upon the requirements for operating clearance between the elements 454. That is, no additional space need be provided to allow for the levers 47.
A plurality of guide rods 63 (FIGURES 4 and 7) are are each pivotally connected at .one end of each to a spacing element =54 by a pivot pin 64 lnear the flange 33. The other end of each guide rod 63 is slideably received through an opening r6.6 in the flange 46 (FIGURE 9). A spiral spring 67 is sleeved upon each rod 63 and is held under compression between the llange 416 and a collar 68 secured on -said rod 63, whereby said rod is urged out of the well 24. Said other end of each rod 63 is threaded and engaged lby a nut y69 for limiting and adjusting lthe .movement of said rod by the spring v67. Each rod 63 bears against the corner 72between the base sheet 32 and the ange 33 when its -associated spacing element is in its raise-d position, as appearing in FIGURE 4. This arrangement tends to hold the spacing element at a substantially uniform distance away from the base sheet 32 `from the guide rod 63 to a point near the at end 6i1 thereof.
A plurali-ty of grippers 73 (FIGURE 8) are secured upon and are simultaneously movable with the gripper shaft 74 so that their tips enga-ge the outer edge of the gripper pad 42 in a substantially conventional manner. Referring Ito the apparatus (FIGURE 4), the gripper pad 42a is disposed slightly outwardly of the surface 27. Thus, a sheet of material 28 engaged between the grippers 73 and the gripper pad 42a is held away from the adjacent portions of .the spacing elements 54a where they tend to remain somewhat closer to the base sheet l32 than at any other point lengthwise thereof, This arrangement also applies to the corresponding parts of the apparatus 10. The antismear apparatus 10a (FIGURE 2) may be substantially identical in other respects to the antismear apparatus 10 described above.
Operation In a preferred embodiment of the invention, the antismear apparatus 10 (FIGURES 6 and 7) or 10a (FIG- URE 2) will Ibe preassemb'led as appearing in FIGURES 6 and 7 prior to installation. However, as discussed hereinafter with respect to fthe disclosure in FIGURE 10, the various parts of the antismear apparatus can be mounted directly upon the transfer drum so `that the 'base sheet 32 is unnecessary, particularly where the press Iis being equipped with the antismear apparatus at its point of manufacture. Nevertheless, even under such circumstances, it may be ydesirable to include the base sheet 32 to simplify the maintenance of the apparatus 10. That is, it might be somewhat easier and require less down time to replace an entire antismear apparatus, when repairs are needed in some cases, than it would to repair the apparatus while it Iis :on the machine.
Under normal circumstances, the antismear apparatus will be designed for a transfer drum having a particular diameter and having a transfer surface of a particular axial and circumferential size. Accordingly, installation of the antismear apparatus can be quickly effected lby fastening the mounting plate 66 in the well 24, for example, and then wrapping the base sheet 32 around the peripheral surface 26 until the flange 34 can be clamped between one side of the well 25 and lthe gripper pad 42. Minor adjustments lof the nut 69 on the guide rod 63 and of the connection between the end 62 4of the spacing ele-ment 54 and its lever `47 may be required for the particular installation. However, with lexperience these .adjustments can generally be made in advance of the installation.
Normally the mounting of the antismear apparatus 10 upon the transfer drum =111 will not adversely affect its operation or the operation of the offset press l12 of which the transfer drum is a part. Accordingly, a printing operation can be promptly commenced in which a piece of sheet stock 2S printed by the printing cylinders in the irst unit 13 can be transferred by the drum 11 to the printing cylinders in the second unit `114 (FIGURE l) with either no smearing whatsoever or an almost negligible amount of same.
More specifically, the `operator determines which parts of the surface on the printed sheet can be engaged along a line lengthwise thereof without contacting the printing on such sheet. Upon selecting such lines, he then manually operates the pawls 49 on the levers 47 controlling those spacing elements extending along said lines. Counter-clockwise movement of the palwl 49, as appearing in FIGURE 9, will permit the spiral spring 67 yon its associated guide rod 63 to urge its corresponding spacing element 54 -rightwardly (FIGURES 7 and 9) and thereby rotate the lever 47 around the pivot shaft 43 in a clockwise direction. When the nut 69 engages the upright flange 46, as shown in FIGURE 4, the spacing element 54 will be in its raised position for engagement with the noninked portion of the printed sheet.
There may be circumstances under which it is virtually impossible to nd a single line along a printed sheet wherein it will be completely clear from printed material. However, it may be possible to ind lines wherein the contact with the printed material will occur at a minimum of points. However, the effectiveness of the antismear apparatus will be reduced very little due to the fact that the spacing elements 54 will contact the sheet stock substantially along a single line and, accordingly, will cross any printed matter, such as a letter, in a very small area, which will produce an almost negligible amount of smearing.
After a particular printing operation has been cornpleted, the raised spacing elements can be returned to their lowered positions against the base sheet 32 by rotating in a clockwise direction, as appearing in FIGURE 4, the levers 47 connected to the raised elements. Thereafter, the antismear apparatus can be prepared for another operation merely by releasing the pawls 49 on the appropriate levers 47 controlling those spacing elements 54 which it is desired to raise for the purpose of engaging the sheet stock along an unprinted line and thereby holding the remainder of the printed sheet away from the other spacing elements 54. It will be seen that these adjustments can be made in a matter of minutes.
The spacing elements 54 will, when their pawls are released, tend to arch away uniformly from the base sheet ansiosa 32 substantially throughout the lengths of said elements 54, except adjacent to the ends of thereof secured to the base sheet 32. However, it has been found that the engagement of the sheet stock between the gripper pad 42 and the grippers '73a will tend to hold the leading end of the sheet stock away from the adjacent ends of the spacing elements 54. On a conventional offset press, this spacing from lthe elements 54 will extend along the sheet stock approximately eight or ten inches. In this distance, the appropriate, released spacing elements 54 will become sufficiently arched away from the base sheet 32 to perform their proper spacing and antismear functions.
Should a piece of folded stock 28 (FIGURE l) pass between an impression cylinder and :the transfer drum il, no material harm is done since the spacing elements 54 will merely flex downwardly against the base sheet 32 under the folded stock. The spiral soring 67 will resiliently absorb such movement without damage to the guide rod 63, and the lever 47 will be able to rotate in a clockwise direction, as appearino in FGURE 4, to protect the element 54 and its associated mechanism. lf desired, means may be provided for holding the pawl 49 away from the ratchet wheel 4S, when its associated element is raised, so `that re-engagement thereof will not be effected. However even without such means, it is only necessary to manually release the pawls 49 of the particular spacing ele "rents that are so affected after the above-mentioned movement of the levers. The levers can be numbered so that a quick check can be made to see that the proper elements 54 are raised.
Thus, it will be seen that the antismear apparatus is not only capable of performing the desired function, but it is also capable of absorbing the type of harsh treatment to which the remainder of the machine may occasionally be subjected.
Modijed structure As mentioned above, FIGURE l illustrates an antismear apparatus di) which is substantially similar to the antismear apparatus l@ (FIGURES 6 and 7) except that there is no base sheet corresponding to the base sheet 32. That is, the spacing elements 81 are mounted directly upon the transfer drum 32 adjacent one side of the single well 83 therein. However, in all other respects, the antismear apparatus 8l) may be substantially the same as the antismear apparatus both in construction and in operation.
FIGURE ll illustrates spacinn elements 9d for an antismear apparatus 91 in which the said elements would run substantially parallel with the axis of the transfer drum. In such case, and to avoid the undesirable effects of friction, inertia and centrifugal force, a plurality of spacers 92. are secured to and extend away from the base sheet 95, which is mounted upon the surface 93 of the rum 94 between each pair of adjacent spacing elements. The fastening of the spacing elements 9d upon the drum 94 at the opposite axial ends thereof could be substantially the same as provided in the mounting of the spacing elements in the antismear apparatus itl. However, leaf springs 98 may be mounted within the channel of each element 90 at selected points lengthwise of said element to urge the element away from the base sheet @S and into its raised position. It will also be seen that this type of construction could also be applied to a fiat bed press to accomplish substantially the same ends.
In conventional offset presses, the peripheral surfaces of the transfer drum and the impression cylinder are spaced about one-fourth of an inch from each other at their nearest points. This provides ample space for the apparatus lil or the apparatus titl, when the spacing elements thereof are in their raised positions.
Since, as mentioned above, there may be times in which there is absolutely no line along a printed sheet where some printing does not exist, `the problem of supporting the sheet without smearing the printing thereon may be further minimized by providing the outer edge of each spacing element 99 with a plurality of spaced, upward projections 96 which would engage the sheet stock 97 along a line of relatively small points of contact. The arrangement not only reduces the chance of contact between the spacing elements and a printed part of the sheet, but also makes possible the use of a wiping roller S5 (FIGURE 1G) which engages the projections 96 during each rotation of the transfer drum and wipes off any ink which might be deposited upon the projections. Any type of conventional, cloth roller could be used for this purpose.
Although particular preferred embodiments of the invention have been disclosed above for illustrative purposes, it will be recognized that variations or modifications of such disclosure, which come within the scope of the appended claims, are fully contemplated.
lil/'hat is claimed is:
l. ln a machine for applying ink indicia to sheet material, said machine including a transfer surface adjacent to which an inked side of said sheet material must be placed before the ink is dry, an apparatus for preventing the smearing of said ink indicia by said surface comprising:
a plurality of substantially parallel elements supported adjacent said surface for movement toward and away from said surface;
means for holding said elements in first positions wherein the sides of said elements remote from said surface are, substantially throughout their lengths, substantially equidistant from said surface; and
means for moving and holding selected ones of said elements away from said surface in second positions where substantial portions of said remote sides of said selected elements are spaced from said surface a substantially uniform distance which is greater than said equal distance.
2. in a printing machine for applying ink indicia to sheet material, said machine having a plurality of cylinders including a transfer cylinder, mechanism for holding the printed side of said sheet material away from the peripheral surface of said transfer cylinder, comprising:
a plurality of spaced, adjacent and substantially parallel elements arranged along the peripheral surface of said transfer cylinder;
means for holding said elements in rst positions adjacent said peripheral surface so that the sides of said elements remote from said peripheral surface are all spaced substantially equal distances from said peripheral surface; and
means for selectively moving and holding said elements in second positions away from said peripheral surface, so that said remote sides of said elements are spaced, substantially throughout their lengths, from said peripheral surface a greater distance than said equal distance, whereby said sheet material can be engaged along lines on the printed side thereof where there is no printed indicia.
3. A mechanism according to claim 2 wherein sai-d elements extend circumferentially 'around and substantially completely cover the peripheral surface of the transfer cylinder;
wherein one end of each element, at corresponding ends thereof, is held with respect to said peripheral surface; and
wherein the other end of each element is movable radially and circumferentially of said peripheral surface.
4. A mechanism according to claim 2 wherein said elements are pivotally connected at corresponding ends thereof to said transfer cylinder adjacent the peripheral surface thereof;
wherein the other end of each element is movable with respect to said peripheral surface; and
wherein said means for holding said elements in said first positions includes a plurality of levers mounted upon said transfer cylinder and movable around a common axis, and a ratchet and pawl device associated with each lever for releasably preventing said movement in one direction around said axis.
5. In an offset printing press capable of applying inked indicia in a plurality of colors to sheet materials and having a transfer drum for advancing the sheet material from one part of the machine to another before ink indicia is dry on said sheet material, mechanism for preventing smearing of the undry ink as the sheet material is moved by said transfer drum, comprising:
a plurality of elongated, slightly spaced and parallel elements extending circurnferentially around and along a substantial portion of the peripheral surface of said transfer drum between the axial ends thereof, each element 'having a substantially U-shaped cross section opening toward said peripheral sur-face;
means connecting .one end of each one of said elements to said transfer drum near one edge of said peripheral surface, the other ends of said elements being located near the other edge of said surface and being movable with respect to said drum both radially and circumferentially thereof;
a plurality of L-shaped levers pivotally supported adjacent the apex of each on said transfer drum for movement -around a common axis parallel with the rotational axis of the drum, each lever being pivotally connected to a said other end of a said element;
pawl and ratchet means for releasably holding said levers Iagainst pivotal movement in one direction, whereby said elements are releasably held by said levers in lirst positions snugly adjacent said peripheral surface of said transfer drum, the radially outer edges of said elements dening a cylindrical surface substantially concentric with, .and only slightly larger in diameter than, the diameter of said transfer drum; and
resilient means connected between said transfer drum and each element near said other end thereof and continuously urging said other ends radially away from said peripheral surface and circumferentially away from said pivot axis, so that release of the pawl and ratchet associated with any given element permits movement thereof radially outwardly from said cylindrical surface, whereby said given element will engage the sheet material along an uninked portion thereon .and hold the printed indicia away from the adjacent elements.
References Cited by the Examiner UNITED STATES PATENTS 3,126,826 3/1964 Fischer -..10i-420 DAVID KLEIN, Primary Examiner.