Abstract:
A system and method of identifying the match of a printing cylinder and sleeve when the combination thereof has been dressed by laser ablation to achieve a degree of cylindricity. It is desirable to retain the identification of this match for reuse purposes and thereby avoid unnecessary redressing. The identification convention of the invention represents simple encoding, conventional marking means, and readability on sight.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    Not Applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]    Not Applicable 
       THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT  
       [0003]    Not Applicable 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC  
       [0004]    Not Applicable 
       BACKGROUND OF THE INVENTION  
       [0005]    1. Field of the Invention 
         [0006]    The field of the present invention is printing. More particularly, the field of the present invention is preparing cylinders and sleeves mounted thereon for optimum cylindricity and marking the relationship therebetween for the benefit of matching in future use scenarios. 
         [0007]    2. Description of Related Art 
         [0008]    It is well-known that printing plates or printing sleeves are mounted on cylinders in a printing operation. The cylinders can include one or more sleeves or other layers thereon. The printing plates are etched or engraved in accordance with a desired image in order to effect the printing operation. It is also known that such etching or engraving of the image on the printing plate can be accomplished by means of a laser. 
         [0009]    Typically, a printing press has a set of cylinders, or built-up mandrels, which are used to increase the diameter of the mandrel in the press. Sleeves corresponding to a plate repeat are mounted onto the cylinder. In the case of a printing sleeve, the sleeve itself is imaged as the plate. A typical printing operation for a 10-color press may have three to six sets of cylinders and 100 to 500 sleeves with inner diameters that correspond to the sets of cylinders. The outer diameter corresponds to the print repeat desired. 
         [0010]    However, a problem with such known arrangements is that the raised surface of the printing plate, when mounted on the cylinders and sleeves, is not adequately cylindrical. In other words, apart from the etched portions, there are variations in the radii at different positions of the raised surface of the printing plate, measured from the center of the cylinder to the raised surface of the printing plate, thereby providing variations in the cylindricity. 
         [0011]    U.S. Pat. No. 7,284,484 to the instant inventor, incorporated herein by reference, describes a method and product to improve the cylindricity of a combination of cylinder and sleeve by laser ablation. This is achieved by a system in which a control device, receiving data on variations in total indicated run-out (TI R) and taper from a detector, instructs a laser in the ablative correction of the sleeve surface to remove the variations through rotational and lengthwise translational movement relative to the sleeve. 
         [0012]    While the method is effective in correcting the printing package, a problem exists in the logistics of matching the components of cylinder, sleeve and plate, or printing sleeve, and storing them for reuse. An identification system is needed to restore the unique match of components, thereby to perpetuate the improvement and save costly regeneration of cylindricity. 
         [0013]    German patent DE 297 20 298 discloses a printing sleeve for a flexographic printing machine in whose envelope surface an electronic memory module configured as a transponder is introduced for the purpose of identification. Similarly, U.S. Pat. No. 7,308,854 to Rossini discloses an embeddable, activatable, signaling device that stores characterization data. Also, U.S. Pat. No. 6,377,772 to Chowdry discloses an indicia for identification purposes on the sleeve of a cylinder of an electrostatographic machine. 
         [0014]    While all of these prior art devices can record, or represent, data, they all require an electronic reader or scanner to interpret the stored information. The recording and reading sophistication of such devices exceeds the simple needs of matching components and introduces unnecessary costs when the storage and cross-referencing of a multiplicity of data is not required. Further, the press operator must carry, or otherwise consult, an electronic display to identify compatible components when a simple visual identification means would suffice. What is needed is a simple marking convention that gives immediate visual recognition to a proper match of components and can be easily and simply applied without embedding electronically-readable assets. 
       BRIEF SUMMARY OF THE INVENTION  
       [0015]    In view of the above-mentioned unfulfilled needs in the prior art, the present invention embodies, but is not limited by, the following objects and advantages: 
         [0016]    A first object of the present invention is to provide a means for identifying a relationship between a sleeve, or a printing sleeve, and a cylinder the combination of which has undergone a customization process specific to the combination. 
         [0017]    A second object of the present invention is to provide a visual means for recognizing the means for identifying without the aid of reading equipment. 
         [0018]    A third object of the present invention is to provide an efficient means for applying the means for identifying to the components thereby related. 
         [0019]    The preferred embodiment of the present invention is a marking convention wherein any cylinder is identified by an outside diameter and a number uniquely indicating one of several cylinders of the same diameter. The marking convention is further comprised of the outside diameter of a sleeve fitted to the cylinder for the purposes of cylindricity dressing by laser ablation combined with a number uniquely indicating one of several sleeves of the same diameter. For example, the identification code, C4.25-1-S4.75-5, identifies the 5th 4.75″ diameter sleeve matched to the 1st 4.25″ diameter cylinder. 
         [0020]    Another aspect of the preferred embodiment is the means by which the marking convention can be applied to the sleeve. The marking convention can preferably be etched on the sleeve surface by the laser following an ablation session. This provides an immediate process which avoids subsequent steps, and ensures the replacement of any indicia previously placed which is removed by erosion in the current session. 
         [0021]    In a second embodiment of the present invention, the marking convention herein described can be applied in identical manner and means to a printing sleeve. 
         [0022]    A third embodiment of the present invention represents a method of identifying a unique relationship between a cylinder and a sleeve fitted thereto for the purposes of laser ablating a cylindricity correction. The method comprises the steps of marking a cylinder with a convention providing a unique identification thereto, mounting a sleeve having a compatible inside diameter and an outside diameter appropriate to the repeat length of a chosen printing plate to the cylinder, measuring the variability cylindricity of the mounted sleeve with respect to cylindricity, laser ablating the sleeve to achieve desired tolerances, marking the sleeve with a unique identification relating the sleeve and cylinder, and repeating the process for each new cylinder and sleeve combination. 
         [0023]    The embodiments and objects herein described are illustrative and not intended to be exhaustive. Other versions, methods and devices can be realized by a person having ordinary skill in the art through insightful reflection and through the practice of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
         [0024]    Various other objects, features and attendant advantages of the present invention will become fully appreciated through consideration of the accompanying drawings and the detailed description following, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0025]      FIG. 1  is a perspective view of a partially assembled sleeve and cylinder. 
           [0026]      FIG. 2  is a diagram of a sleeve and cylinder marking convention. 
           [0027]      FIG. 3  is a method diagram according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]    Referring to  FIG. 1 , a sleeve and cylinder assembly  10  is shown. For the purpose of definition, a printing cylinder  12  is mounted on mandrel  11  either while in the press, or out of the press. The printing cylinder  12  is also known as build up mandrel or intermediate plate cylinder. The sleeve  13  is mounted to the printing cylinder  12 , and the package can be mounted into the press, or assembled on the press. Sleeve  13  is shown in partial assembly to printing cylinder  12  where the sleeve jackets the cylinder. Printing plate  14  is mounted on sleeve  13 . An indicia  16  according to a sleeve marking convention  17  is shown on the surface of sleeve  13  at an easily readable location near the edge. The sleeve  13  can also be considered to be a printing sleeve for the purposes of this description, except that a printing plate would not, in this case, be mounted thereto. 
         [0029]    Referring to  FIG. 2 , a cylinder marking convention  15  and a sleeve marking convention  17  are shown. As seen from the cylinder marking convention  15 , each cylinder is marked to show two components of information, which include the outside diameter of the cylinder and a number that distinguishes the cylinder from other cylinders of the same diameter. As seen from the sleeve marking convention  17 , each sleeve is marked with four components of information. The first two represent the cylinder to which the sleeve is associated. The third number represents the outside diameter of the sleeve and the final number distinguishes the sleeve from other sleeves of the same diameter. The letters “C” and “S”, or another appropriate indicia, may precede the diameters to distinguish a cylinder diameter from a sleeve diameter, unless the order of presentation is a part of the convention. 
         [0030]    While the above marking convention is exemplary, it is to be considered only one of many within the conceptual framework of the present invention. In fact, any convention which relates the unique codes, symbols, or signatures of a discreet cylinder and a discreet sleeve having a relationship by virtue of customization of the cylinder and sleeve as a unit, is comprehended by this invention. By way of illustration, a convention of the form XXXYYY, where XXX is any sequence of any multiplicity of letters or numbers which uniquely identifies either of the cylinder or the sleeve, and YYY is any sequence of any multiplicity of letters or numbers which uniquely identifies the other of the cylinder and the sleeve, is a convention envisioned by the present invention. The above scheme can be expanded to XXXYYYZZZ, where ZZZ represents a third component, such as a printing plate. 
         [0031]    Another illustrative convention is of the form X1X2Y1Y2, where the Xs refer by 1st position to the cylinder and the Ys refer by 2nd position to the sleeve, or visa versa, and X1 and Y1 are letters or numbers uniquely indicating one of several diameters and X2 and Y2 are letters or numbers uniquely indicating one of several cylinders or sleeves of those diameters in a given relationship. 
         [0032]    According to a method embodiment of the present invention, as shown in  FIG. 3 , a printing cylinder  12  and associated sleeves are corrected and marked according to the cylinder marking convention  15  and the sleeve marking convention  17 . In step  50 , a printing cylinder  12  is selected and marked according to the cylinder marking convention  15  described in  FIG. 2 . Next, in steps  51 - 53 , the cylinder and sleeve combination are corrected for cylindricity. In step  54 , the sleeve is marked according to the sleeve marking convention  17  as shown in  FIG. 2 . Lastly, in step  55 , the process is repeated for each new sleeve and cylinder combination. 
         [0033]    It is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the preceding description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.