Abstract:
In order to provide a printing unit ( 1; 50 ) of modular design with the lowest possible expenditure on construction and high flexibility, the printing unit ( 1; 50 ) of modular design for printing webs ( 29 ) has a stand ( 2; 2′; 54 ), which is provided with at least one crossmember ( 3; 4; 51 ) at both ends (drive and operating side), printing cylinders ( 9  to  16 ) being mounted in the crossmembers ( 3; 4; 51 ) in such a way that a structural unit comprising crossmembers ( 3; 4; 51 ) and printing cylinders ( 9  to  16 ) can be taken completely out of and put into the stand ( 2; 2′; 54 ).

Description:
PRIORITY CLAIM 
     This is a U.S. national stage of application No. PCT/EP2003/014208, filed on 13 Dec. 2003. Priority is claimed on the following application(s): Country: Germany, Application No.: 102 60 574.2, Filed: 21 Dec. 2002. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a printing unit for printing webs. 
     The object of the invention is to provide a printing unit which is designed with the lowest possible expenditure on construction and high flexibility. 
     SUMMARY OF THE INVENTION  
     The modular printing unit according to the invention comprises three main groups a frame; subunits; and at least one cross member:
         the frame, performs the load-bearing function and accommodates all the services and operating elements (alternatively a stand configured in the manner of a frame can also be used),   the format-independent “subunits” are mounted in the frame or stand and which contain the auxiliary subassemblies necessary to the printing process (In the offset process which is common nowadays, the subunits mainly include inking and damping units), and   the at least one crossmember is configured as a “locking bar”, which is arranged in the frame or connected to the stand on both sides and in which the main subassemblies necessary for printing—plate cylinders and rubber-covered cylinders in offset printing—are mounted.
 
In addition, additional equipment such as plate loading systems or digital imaging systems (direct imaging) can be mounted in the crossmember.
       

     Each crossmember is equipped with one or more swinging arms for what are known as the printing mechanisms, in order to pivot the rubber-covered cylinders. 
     A great advantage of this system is the independence of the printing process, so that adaptations to the future innovations are possible at any time by replacing the corresponding subassemblies. In addition, the fundamental change or adaptation to other printing processes and to all varieties of offset printing can be covered. By means of the appropriate adaptation of the subunits and/or the crossmember, the printing unit can be extended or converted to anilox, dry offset printing, gravure printing or any printing process developed in the future, with its preconditions. 
     The modular printing unit of the present invention may be configured as an H printing unit equipped with 1, 2, 3, 4 or more printing points or a modular printing unit configured as an I printing unit with 1, 2 or more printing points. In the I design, imprinting mechanisms may also be installed. The subunits of the modular printing unit are preassembled for this purpose and are attached to the frame. 
     The ratio of the plate cylinders to rubber-covered cylinders mounted in the crossmember can be x:x or x:y (for y&gt;x), but advantageously 1:1, 1:2 and 2:2. However, 2:3, 3:3 and so on are just as conceivable. 
     The proportion of the wall for inking and damping units is separate from the proportion of the wall for plate cylinders and rubber-covered cylinders and is called a “subunit” here. The inking units can alternatively contain 1, 2, 3 or 4 and more ink applicator rolls and as many distributor cylinders as desired. The damping units can alternatively contain 1 or 2 damping solution transfer rolls and as many distributor cylinders as desired. Inking and damping units can also be connected to one or more “coupling rolls” for indirect damping. 
     The rubber-covered cylinder is pivoted out by means of a swinging arm arranged in the crossmember for good accessibility (for example replacement of the rubber-covered cylinder cover, removal of a wrap); the pivot for this purpose is advantageously located at the center of the plate cylinder. Translational movements are not absolutely necessary but there is the possibility of displacing the impression cylinder, rubber-covered cylinder and plate cylinder arranged in the crossmember in the translational direction in relation to one another. 
     The subunits are designed in a modular way, which are advantageously constructed identically, these primarily accommodating inking and damping units. As a result of the identical structure of the subunits, these can advantageously be given the same dimensions, which improves the replaceability and minimizes the production costs. 
     From this, in the case of identical subunits, it is possible to derive
         a) H printing units with identical height and, if appropriate, format-dependent different width with a horizontal crossmember and   b) I printing units with identical widths and, if appropriate, format-dependent different height with vertical crossmember.       

     By means of the combination of a top left and bottom right subunit designed in a modular way, it is possible to construct an I printing unit for a left-right machine; by means of the combination of a top right and bottom left subunit designed in a modular way, it is possible to construct an I printing unit for a right-left machine. 
     The plate cylinders and rubber-covered cylinders may be arranged in the crossmember in one line parallel to the crossmember, crossed in any direction or arranged at angles to one another. 
     The modular printing unit can be equipped with various types of drive:
         an H drive for the simultaneous drive of four printing mechanisms, integrated in the frame;   a bridge drive for the simultaneous drive of two printing mechanisms, integrated in the crossmember, advantageously positioned at the center of the plate cylinder and driving the rubber-covered cylinder via drive elements; or   an individual drive for each printing mechanism, integrated in the crossmember, advantageously positioned at the center of the plate cylinder and driving the rubber-covered cylinder via drive elements, or integrated in the respective subunit.       

     In order to throw the print on and off, plate cylinder and rubber-covered cylinder can be moved toward each other via eccentrics. 
     The frames, crossmembers and swinging arms can be created constructionally simply and, as a result, cost-effectively. For example, the crossmembers can be implemented with commercially available profiles. In addition, the printing units configured by means of the frame, the crossmembers and the swinging arms are distinguished by a reduced-weight, compact and space-saving design. 
     Thus, using one and the same printing unit, it is possible to print as desired in the gravure printing or offset printing process, it being possible for the machine to be converted simply from one process to the other as a result of the modular design and the replacement of the crossmember fitted with the appropriate cylinders and the replacement of the corresponding modular subunits. In addition, both printing processes can be used simultaneously. Furthermore, for example the one printing process can be used for the recto printing and the other printing process can be used for the verso printing. The press manufacturer can create the machines for both processes identically from the same components, which permits cost-effective fabrication. In addition, the printing devices can be designed with variable format, that is to say they can be converted simply to other formats, i.e. other diameters of the printing mechanism cylinders and section lengths. Moreover, the printing unit can be changed over quickly to different production variants. Furthermore, the printing unit can also be converted to a varnishing unit or at least as a varnishing mechanism for recto printing or for verso printing. 
     It is significant that a printing unit of modular design is provided for printing webs, which has a stand which is provided with at least one crossmember at both ends (drive side and operating side), printing cylinders being mounted in the crossmembers in such a way that a structural unit comprising crossmembers and printing cylinders can be taken completely out of and put into the stand. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       In the drawings, wherein like reference characters denote similar elements throughout the several views: 
         FIG. 1  is a schematic side view of a printing unit according to the invention, configured as an H printing unit having four printing points, 
         FIG. 2  is a sectional plan view of a drive of a printing mechanism according to  FIG. 1 , 
         FIG. 3  is a sectional plan view of a further drive of a printing mechanism according to  FIG. 1 , 
         FIGS. 4   a  and  4   b  are side views of a printing unit according to the invention configured as an I printing unit, 
         FIGS. 5   a  and  5   b  are schematic side views of shows the subunits in printing machines having different formats. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       FIG. 1  shows a printing unit  1  of a web-fed rotary press, comprising a stand  2  constructed in the manner of a frame. Two crossmembers  3 ;  4  are connected to the latter on both sides (only one side is shown in  FIG. 1 ), in each case two printing mechanisms  5  to  8  having plate cylinders  9  to  12  and rubber-covered cylinders  13  to  16  being arranged in the crossmembers  3 ;  4  and the crossmembers  3 ;  4  being arranged horizontally in the stand  2 . The plate cylinders  9  to  12  and the rubber-covered cylinders  13  to  16  are here arranged in line in the crossmember  3 ;  4 . They can be arranged in the crossmember  3 ;  4  crossed in any direction or at angles to one another, not illustrated here. Each printing mechanism  5  to  8  or each plate cylinder  9  to  12  is connected to a subunit  17  to  20  of modular design, the subunit  17  to  20  being arranged between the respective crossmember  3 ;  4  and the stand  2 . Inking and damping units, not specifically illustrated, are integrated in the subunits  17  to  20 . 
     The printing unit  1  equipped with four printing mechanisms  5  to  8  in this way represents what is known as an H printing unit with four printing points. A web  29  to be printed is led through between the rubber-covered cylinders  13  to  16 . The printing mechanisms  5  to  8  print the web  29  on both sides. 
     The rubber-covered cylinder  13 ; to  16  can be configured as an impression cylinder  50 , the respective form cylinder  9  to  12  belonging to the rubber-covered cylinder  13  to  16  now designed as an impression cylinder  42  being omitted. When impression cylinder  50  is used, the web  29  is thus printed on one side. 
     The respective rubber-covered cylinder  13  to  16  can be pivoted on the crossmember  3 ;  4  by means of a swinging arm  21  to  24 , the pivot of the swinging arm  21  to  24  preferably being an axle  25  to  28  of the respective plate cylinder  9  to  12 . The crossmember  3 ;  4  is screwed to the stand  2  on both sides (not specifically illustrated), so that, for example, replacement of the respective printing mechanisms  5  to  8  can be effected quickly. 
     The crossmember  3 ;  4  consists, for example, of sheet metal turned over at the edge or sheet metal profiles. The printing cylinders  9  to  16  can be moved in relation to each other via bearing points configured as eccentrics in order to throw the print on/off. 
       FIG. 2  shows a drive  30  of the printing mechanism  5 . The drive  30  comprises a drive motor  31  which has a drive connection to the plate cylinder  9  via a clutch  32 . The plate cylinder  9  is connected to the rubber-covered cylinder  13  via gears  33 ;  34  arranged on their axles  25 ;  35 . The drive motor  31  is arranged on a bracket  36  connected to the crossmember  3 . Mounted on the axle  25  of the plate cylinder  9  is the swinging arm  21 , which can be pivoted about the axle  25  by means of a pivoting motor  38  which is fixed to the bracket  36  and engages with a toothed segment  37  arranged on the winging arm  21 . Before the pivoting action, a locking device  39  has to be released which, during printing operation, connects the swinging arm  21  to the bracket  36  in a locking manner. It is self-evident that the crossmember  3  is equipped with a cutout  40  along the pivoting travel of the axle  35  of the rubber-covered cylinder  13 . Although not specifically illustrated, the swinging arm  21  can also be pivoted by means of an operating cylinder operated by pressure medium instead of by means of the pivoting motor. 
       FIG. 3  shows a variant of  FIG. 2 . Here, the drive motor  31  drives the rubber-covered cylinder  13  for example via a drive element  41 , for example a toothed belt. In a manner analogous to  FIG. 2 , the drive motor  31  is located in its position at the center M p  of the plate cylinder  9 , in order that it does not change its position when the rubber-covered cylinder  13  is pivoted out. 
       FIGS. 4A and 4B  a printing unit  50  which is configured as an I printing unit. In an I printing unit  50 , the crossmember  51  is, for example, configured in the shape of a T and the web  29  is led through the printing unit  50  in the horizontal direction. The I printing unit  50  can be equipped with 1 or 2 printing points. Thus, imprinting mechanisms can also be incorporated in an I design. The subunits  52 ;  53  are preassembled in a way analogous to  FIG. 1  for this purpose and are fitted in the stand  54 . 
     By means of the combination of a top left  52  and bottom right subunit  53  designed in a modular way, it is possible to construct an I printing unit  50  for a left-right machine (see  FIG. 4A ); by means of the combination of a top right  55  and bottom left subunit  56  designed in a modular way, it is possible to construct an I printing unit  50  for a right-left machine (see  FIG. 4B ). 
     The subunits  17  to  20  are shown in  FIGS. 5A and 5B  are arranged in two different stands  2 ;  2 ′. The subunits  17  to  20  always have the same dimensions, it being possible for the stands  2 ;  2 ′ to be different in their format or in their dimensions, the dimension and the format of the stands  2 ;  2 ′ depending on the number and dimension of the printing cylinders used. While viewing the two illustrations shown in  FIGS. 5A and 5B , it is possible to see the identically dimensioned subunits  17  to  20 , but with the format difference between the stands  2 ;  2 ′ represented by ΔB in  FIG. 5B .