Abstract:
A ribbon transport apparatus for a printing press is provided. The ribbon transport apparatus includes a vacuum conveyor belt transporting a ribbon and a manifold supporting the vacuum conveyor belt. The vacuum conveyor belt and the manifold are arranged to draw the ribbon towards the vacuum conveyor belt via a suction. A method of transporting a ribbon in a printing press is also provided.

Description:
[0001]    The present invention relates generally to printing presses, and more particularly to web printing presses with web guiding apparatuses. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the web offset printing process, a continuous web of paper is transported through a printing press. Near the beginning of the press, one or more printing units may apply ink to the web to repeatedly create a pattern, or impression, of text and images. At the end of the press, a web conversion machine, such as a folder, may be used to cut and fold the web into signatures. 
         [0003]    To convert a web into signatures, the web may be slit into ribbons, and the ribbons may be redirected by lead rolls and angle bars into a stacked configuration for subsequent folding and cutting. Ribbons may be transported with each edge being an equal distance above the floor or with the ribbons traveling on-edge so that one edge is above the other. With on-edge ribbon transport, it can be more difficult to install the ribbons in the machine, and the ribbons may be more likely to fall to the floor when they break. 
       SUMMARY OF THE INVENTION 
       [0004]    A ribbon transport apparatus for a printing press is provided. The ribbon transport apparatus includes a vacuum conveyor belt transporting a ribbon and a manifold supporting the vacuum conveyor belt. The vacuum conveyor belt and the manifold are arranged to draw the ribbon towards the vacuum conveyor belt via a suction. 
         [0005]    A method of transporting a ribbon in a printing press is also provided. The method includes the steps of pulling air through holes of a vacuum conveyor belt to draw a ribbon to a surface of the vacuum conveyor belt and translating the vacuum conveyor belt to transport the ribbon. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The present invention is described below by reference to the following drawings, in which: 
           [0007]      FIG. 1  schematically shows a perspective view of a ribbon guiding section of a ribbon transport apparatus according to an embodiment of the present invention; and 
           [0008]      FIG. 2  schematically shows a plan view of the ribbon guiding section shown in  FIG. 1 ; 
           [0009]      FIG. 3  schematically shows a plan view of a ribbon transport apparatus according to an embodiment of the present invention; and 
           [0010]      FIG. 4  schematically shows a plan view of a ribbon transport apparatus according to another embodiment of the present invention transporting ribbons to a former. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]      FIG. 1  schematically shows a perspective view of a ribbon guiding section  10  of a ribbon transport apparatus according to an embodiment of the present invention. Ribbon guiding section  10  includes a vacuum conveyor belt  12 , a vacuum chamber manifold  14 , and a lead roll  16 . In this embodiment, a center axis CA 1  is aligned in the vertical direction and an outer surface  40  of vacuum conveyor belt  12  is aligned in the vertical direction, such that ribbon guiding section  10  may act to direct a ribbon  38 , while maintaining the vertical orientation of ribbon  38 , with one edge of ribbon  38  over the other, during a break or tear in ribbon  38 . 
         [0012]    Ribbon  38  may include a plurality of ribbons. Manifold  14  and lead roll  16  form a path for vacuum conveyor belt  12  to travel. Vacuum conveyor belt  12  is supported on lead roll  16  by an undercut  22  in lead roll  16 , which acts to control the orientation of vacuum conveyor belt  12 . Undercut  22  is machined into lead roll  16  in a manner such that undercut  22  extends radially into lead roll  16  a depth that is equal to or greater than a thickness of conveyor belt  12 . Undercut  22  is continuous throughout a circumference of lead roll  16 . Manifold  14  supports vacuum conveyor belt  12  as vacuum conveyor belt  12  travels towards and away from lead roll  16 , and is arranged to allow vacuum conveyor belt  12  to wrap around a front side  18  of lead roll  16  in undercut  22 . A portion  15  of manifold  14  that is upstream of lead roll  16  is angled in relation to a portion  17  of manifold  14  that is downstream of lead roll  16 . Manifold  14  is a continuous body and between portions  15 ,  17 , manifold  14  wraps around a back side  20  of lead roll  16  and ceases to contact vacuum conveyor belt  12  as vacuum conveyor belt  12  contacts undercut  22  of lead roll  16 . 
         [0013]    Vacuum conveyor belt  12  is shown as being discontinuous in order to show manifold  14  in better detail, but is a continuous belt traveling in a continuous loop. A continuous view of conveyor belt  12  traveling in a loop is shown in  FIG. 2 . Vacuum conveyor belt  12  and lead roll  16  are perforated with holes  26  and  28 , respectively. In order to draw ribbon  38  to the surface of vacuum conveyor belt  12  and to outer surface  24  of front side  18  of lead roll  16 , a pump  110  draws air into manifold  14  through holes  26  and into lead roll  16  through holes  28 . Lead roll  16  may be sealed at a bottom edge  30  and a top edge  32 . A sealing contact is formed between manifold  14  and conveyor belt  12  along an edge  34 . A center support  36  in manifold  14  prevents vacuum conveyor belt  12  from being drawn into manifold  14 . 
         [0014]    During operation of ribbon guiding section  10 , a motor  100  rotates lead roll  16  about center axis CA 1  at a surface velocity V 1  and vacuum conveyor belt  12  slides along manifold  14  and in undercut  22  of lead roll  16  at velocity V 1 . Vacuum conveyor belt  12  and lead roll  16  are used to transport ribbon  38  along the path of vacuum conveyor belt  12  at velocity V 1 . When ribbon  38  is placed against outer surface  40  of vacuum conveyor belt  12 , ribbon  38  adheres to vacuum conveyor belt  12  due to the lower pressure inside manifold  14 . Ribbon  38  is carried by vacuum conveyor belt  12  to lead roll  16  where ribbon  38  adheres to outer surface  24  due to lower pressure inside lead roll  16 . Rotation of lead roll  16  causes ribbon  38  to wrap around front side  18  of lead roll  16 . Vacuum conveyor belt  12 , following a path of second portion  17  of manifold  14 , ensures that vacuum conveyor belt  12  does not wrap further around lead roll  16  to back side  20 , and transport ribbon  38  away from lead roll  16 . 
         [0015]    Although  FIG. 1  shows vacuum conveyor belt  12  positioned in the middle of lead roll  16 , vacuum conveyor belt  12  may be positioned anywhere between bottom edge  30  and top edge  32  of lead roll  16 . Additionally, the height of vacuum conveyor belt  12  may be varied as necessary to maximize support and transport of ribbon  38 . 
         [0016]      FIG. 2  shows a plan view of ribbon guiding section  10  shown in  FIG. 1 . Vacuum conveyor belt  12  transports ribbon  38  past lead roll  16 . Lead roll  16  includes undercut  22 , which is defined by an inner circumference  29 . A path of vacuum conveyor belt  22  is defined by manifold  14  and front side  18  of lead roll  16 . Manifold  14  is arranged such that portion  15  of manifold  22  supports vacuum conveyor belt  12  as vacuum conveyor belt  12  travels towards lead roll  16  and portion  17  of manifold  22  supports vacuum conveyor belt  12  as vacuum conveyor belt  12  travels away from lead roll  16 . Undercut  22  in lead roll  16  supports vacuum conveyor belt  12  as vacuum conveyor belt  12  passes lead roll  16 . As vacuum conveyor belt  12  transports ribbon  38  past lead roll  16 , ribbon  38  adheres to outer surface  24  of lead roll  16 . Vacuum conveyor belt  12 , along with manifold  14 , separates ribbon  38  from lead roll  16  at point  39 , where vacuum conveyor belt  12  comes out of contact with undercut  22 . Friction between vacuum conveyor belt  12  and a surface of inner circumference  29  of undercut  22  allows lead roll  16  to help transport vacuum conveyor  12  as lead roll is rotated. 
         [0017]      FIG. 3  schematically shows a plan view of a ribbon transport loop  50  according to an embodiment of the present invention. Vacuum conveyor belt  12  is wrapped around lead rolls  16 ,  116 , a pull roll  62  and return rolls  64  in a continuous loop. Lead rolls  16 ,  116  and pull roll  62  have undercuts to prevent vacuum conveyor belt  52  from protruding beyond outer surfaces of lead rolls  16 ,  116  and pull roll  62 . Return rolls  64  may also be undercut to prevent vertical slipping of vacuum conveyor belt  12 . 
         [0018]    Ribbon  38  enters ribbon transport loop  50  near a first end  68  of manifold  14 . An idle roller  58  helps guide ribbon  38  as ribbon  38  comes into contact with vacuum conveyor belt  12 , which is being continuously translated about lead rolls  16 ,  116 , return roll  64  and pull roll  62 . Vacuum conveyor belt  12 , forming a suction with manifold  14 , transports ribbon  38  to lead roll  16 . As vacuum conveyor belt  12  passes lead roll  16 , vacuum conveyor belt  12  comes out of contact with manifold  14  and passes through undercut  22  (see  FIG. 1 ) in lead roll  16 . Ribbon  38  is drawn to the surface of lead roll  16  and is transported by lead roll  16  as lead roll  16  rotates. As vacuum conveyor belt  12  exits undercut  22  (see  FIG. 1 ) of lead roll  16  ribbon  38  is drawn away from lead roll  16  and vacuum conveyor belt  12  comes back into contact with manifold  14 . 
         [0019]    Vacuum conveyor belt  12 , following a path of manifold  14 , transports ribbon  38  from lead roll  16  to lead roll  116 . Manifold  14  comes out of contact with vacuum conveyor belt  12  as vacuum conveyor belt approaches lead roll  116 . Lead roll  116  is configured similar to lead roll  16  and transports ribbon  38  in the same manner as lead roll  16 . Lead roll  116  includes an undercut similar to undercut  22  (see  FIG. 1 ) and interacts with vacuum conveyor belt  12  in the same manner as lead roll  16 . After vacuum conveyor belt  12  comes out of contact with undercut  22 , vacuum conveyor belt  12  is guided by manifold  14  again unit a second end  70  of manifold  14 . Vacuum conveyor belt  12  transports ribbon  38  past end  70  to pull roll  62 . Ribbon  38  is pulled away from ribbon transport apparatus  50  at pull roll  62  by an RTF  76 , which transports ribbon  38  to a former for longitudinal folding. 
         [0020]    During operation of ribbon transport loop  50 , a motor rotates pull roll  62  about a center axis CA 2  at a velocity V 2 , causing vacuum conveyor belt  12  to travel around the loop at velocity V 2 . When a ribbon  38  is placed against vacuum conveyor belt  52  at first end  68 , ribbon  38  adheres to vacuum conveyor belt  52  due to lower pressure inside manifold  54 . 
         [0021]    The center axes of idler roll  58 , lead rolls  16 ,  116  and pull roll  62  may be aligned vertically or horizontally. Vacuum conveyor belt  52  may thus transport ribbon  38  on-edge, as shown in  FIG. 3 , so that one edge of ribbon  38  is above the other edge, or not on-edge, so that both edges of ribbon  38  are approximately the same distance above the floor. 
         [0022]    Unlike web-up chains requiring a cross member to be positioned and attached to the lead edge of ribbon  38 , vacuum conveyor belt  12  does not require the use of a cross member. Ribbon  38  may be attached to vacuum conveyor belt  12  anywhere along loop  66  between first end  68  and second end  70 . 
         [0023]    Vacuum conveyor belt  12  may also be used to transport ribbon  38  after initial installation of ribbon  38 . When a web break or ribbon break occurs, vacuum conveyor belt  12  may continue to hold and carry ribbon  38 , thereby preventing ribbon  38  from falling to the floor. Vacuum conveyor belt  12  thus may advantageously facilitate recovery from web breaks or ribbon breaks. When a web break or ribbon break occurs, vacuum conveyor belt  12  may continue to hold and carry ribbon  38 , thereby preventing ribbon  38  from falling out of place and preventing ribbon weave. Vacuum conveyor belt  12  thus may advantageously facilitate recovery from web breaks or ribbon breaks. 
         [0024]    Vacuum conveyor belt  12  and manifold  14  could extend beyond pull roll  62  and be used to carry ribbon  38  away from RTF  76  in the event of a web or ribbon break. The broken ribbon could be collected on a spool and later discarded or reused. 
         [0025]    Although  FIG. 3  shows only ribbon  38  and one ribbon transport loop  50 , additional loops may be employed to transport additional ribbons. Multiple vacuum conveyor belts may make it easier to install multiple ribbons because access to the ribbons can be limited, particularly when the ribbons are transported on-edge. By facilitating ribbon installation, ribbon paths may thus advantageously be placed closer together, saving valuable space. 
         [0026]      FIG. 4  schematically shows a plan view of a ribbon transport apparatus  120  according to another embodiment of the present invention transporting multiple ribbons  102 ,  103 ,  104 ,  105 ,  106 ,  107  to a former  82 . Each ribbon  102 ,  103 ,  104 ,  105 ,  106 ,  107  is transported by a respective ribbon transport loop  92 ,  93 ,  94 ,  95 ,  96 ,  97 . Each ribbon transport loop  92 ,  93 ,  94 ,  95 ,  96 ,  97  is configured similar to ribbon transport loop  50  shown in  FIG. 3 . Each ribbon transport loop  92 ,  93 ,  94 ,  95 ,  96 ,  97  may include lead rolls  16 ,  116 , return rolls  64 , idler rolls  58 ,  63 , vacuum conveyor belt  12  and manifold  14 . Ribbons  102 ,  103 ,  104 ,  105 ,  106 ,  107  are drawn together to form a ribbon bundle  86  by RTF  76 . Ribbon bundle  86  is longitudinally folded by former  82  and transported away from ribbon transport apparatus  12  by nip rolls  84  for further processing, such as cutting, cross-folding and other finishing operations. 
         [0027]    Vacuum conveyor belts could be used to stabilize ribbons during a production run or eliminate the need to tram and level the lead rolls to a fine precision. The vacuum conveyor belt traction would overcome the lateral forces from an out of tram roll. Undercuts in lead rolls  16 ,  116  and pull rolls  62  could have a small crown to help steer vacuum conveyor belts  12  and ribbons  102 ,  103 ,  104 ,  105 ,  106 ,  107 . 
         [0028]    In the preceding specification, the invention has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.