Patent Publication Number: US-6698350-B2

Title: Sheet perfecting apparatus for satellite-type printing press

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to satellite-type printing press for sheet-fed printing, or more precisely, to sheet perfecting apparatus for such printing press. 
     2. Description of the Prior Art 
     Satellite-type printing press is known in which many printing units (four color units, for example) are provided in satellite-like manner around common pressure cylinder of large diameter. Such satellite-type printing press is a new step toward corresponding to the need of multi-sort short run printing. 
     In Japanese unexamined patent laid-open 244195/1996, a technique is disclosed in which a plurality of satellite-type printing presses are connected via sheet perfecting apparatus. According to the technique, four color printing is done on the surface of sheet by first satellite-type press and, after reversing the sheet, also four color printing is put on the opposite side of the sheet by the second satellite-type press. 
     From Japanese unexamined patent laid-open 169645/1987, for example, a technique is well known in which many printing units are connected in series and sheet perfecting apparatus is interposed therein. 
     It is true that both sides of sheet can be printed at one pass by the satellite-type printing press shown in before-mentioned Japanese unexamined patent laid-open 244195/1996, but the equipment is huge and switching of printing format is not at all flexible, as the technique presupposes two satellite-type printing units. 
     Also, before-mentioned sheet perfecting apparatus of series type printing press has a tendency to cause register error through gripping change of sheet, as the perfecting apparatus stays the sheet transfer path during one-side printing in which sheet perfecting is not needed. 
     SUMMARY OF THE INVENTION 
     In view of the above-described problems of the prior art techniques, the present invention provides an improved sheet perfecting apparatus for satellite-type printing press and aims at enabling double-side printing by only one satellite-type printing press itself, and preventing register error without connecting with sheet transfer path in case sheet reversing is not needed. 
     In accordance with sheet perfecting apparatus of the present invention, in the course of many printing units which are provided in satellite-like manner around a common pressure cylinder, a plurality of chain gripper means are paralleled and these means are connected via a perfecting cylinder. 
     The first chain gripper means accept the front end of sheet from common pressure cylinder and the sheet is then turned toward distant direction of common pressure cylinder. In the course of such sheet transfer, the rear end of sheet is gripped by perfecting gripper of perfecting cylinder and the sheet is reversed in accordance with the rotation of the cylinder. Then, the sheet is approached and transferred from the second chain gripper means to common pressure cylinder. 
     These and other objects of the invention will become apparent from the following description with reference to the drawings. But, these show merely an embodiment of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view showing an embodiment of sheet perfecting apparatus for satellite-type printing press according to the present invention. 
     FIG. 2 shows the first chain gripper means and perfecting cylinder of sheet perfecting apparatus. 
     FIG. 3 shows a state in which rear end of sheet is gripped by perfecting gripper of perfecting cylinder. 
     FIG. 4 shows a state in which sheet is reversed in accordance with the rotation of perfecting cylinder. 
     FIG. 5 mainly shows second gripper means of sheet perfecting apparatus. 
     FIG. 6 shows a state in which sheet is returned to common cylinder. 
     FIG. 7 shows a state in which sheet perfecting apparatus has no connection with sheet transfer path. 
     FIG. 8 shows a state in which position of perfecting cylinder is adjusted in accordance with sheet length. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     In the center of FIG. 1, common pressure cylinder  10  of relatively large diameter is shown which is rotatably supported between a pair of side frames  12  of printing press and is driven by motor (not shown). 
     The common pressure cylinder  10  has grippers  16  which grip the end of sheet. The common pressure cylinder  10  is a base for accepting sheet  14  from feeding cylinder  20  of sheet feeder  18  in the upper stream and, after printing, for delivering the printed sheet to delivery chain  24  of sheet delivery device  22  in the lower stream. 
     Four sets of printing units  26  are provided in satellite-like manner around the common pressure cylinder  10 . In order to perform offset printing, these printing units  26  have plate cylinder  28  equipped with printing plate and blanket cylinder  30  to transfer images. In addition, the plate cylinder  28  has inking device  32  and damping system  34 . The diameter of the common pressure cylinder  10  around which printing units  26  are provided in satellite-like manner is integer times (for example, four times) as large as that of plate cylinder  28  in order to perform multi-color printing by these printing units  26  in compliance with the rotation of the common pressure cylinder  10  which is driven by motor (not shown). 
     Sheet perfecting apparatus  36  according to the present invention is provided between second and third printing units  26 , basing upon rotational direction of common pressure cylinder  10  (counterclockwise in FIG.  1 ). From upper stream to down stream of sheet transfer path, the sheet perfecting apparatus  36  comprises first chain gripper means  38 , perfecting cylinder  40  and second chain gripper means  42 . 
     The concrete construction of first chain gripper means  38  can be imagined from delivery chain  24  of sheet delivery device  22 . A pair of sprocket wheels  44 ,  46  are provided near the circumference and upright position of common pressure cylinder  10  and rotatably supported by side frame  12  of printing press. Chain  48  is wound between sprocket wheels  44 ,  46 . (Also, another chain is wound between another pair of sprocket wheels which are provided at intervals perpendicular to the figure.) Grippers  50  are attached at proper intervals to supporting bar (not shown) which is extended between chain  48 . Running of chain  48  for first chain gripper means  38  and opening as well as shutting of gripper  50  are timed by drive force from printing press. Position of gripper  50  in longitudinal direction of chain  48  is decided upon that of gripper  16  on common pressure cylinder  10 . 
     As shown in FIG. 2, running direction of chain  48  is clockwise in the figure, in other words, the direction that accepts front end of sheet  14  and lead it to remote direction from circumference of common pressure cylinder  10 . 
     Perfecting cylinder  40  of sheet perfecting apparatus  36  is situated between first and second chain gripper means  38 ,  42  which run in parallel and perfecting gripper  52  is swingably provided around circumference of cylinders. As to perfecting gripper  52 , a pair of fingers are opened as well as closed for gripping sheet  14  end and gripper  52  swings around axis  54  for position control. Such perfecting gripper  52  is well known in the prior art series-type printing press. Perfecting cylinder  40  is rotatably supported between side frames  12  and, as shown in FIG. 8, moved in parallel to first and second chain gripper means  38 ,  42  far and near from common pressure cylinder  10  in compliance with sheet length (length of sheet  14  in its running direction). In concrete, support portion of perfecting cylinder  40  is groove-fitted with side frame  12  and slidably adjusted in compliance with sheet length. As second chain gripper means  42  accepts drive force from printing press, perfecting cylinder  40  further takes up its rotation force from second chain gripper means  42 . 
     Construction of second chain gripper means  42  is similar to that of first chain gripper means  38 . As shown in FIG. 5, chain  60  is wound between sprocket wheels  56 ,  58  near the circumference and upright position of common pressure cylinder  10 . (Also, another chain is wound between another pair of sprocket wheels which are provided at intervals perpendicular to the figure.) Grippers  62  are attached at proper intervals to supporting bar (not shown) which is extended between chain  60 . Running direction of second chain gripper means  42  is also clockwise in the figure. The substantial role is accepting sheet  14  end and transferring it to common pressure cylinder  10 . 
     In case of one-side printing (surface printing) in which sheet perfecting is not needed, sprocket wheels  44 ,  56  of first and second chain gripper means  38 ,  42  are separated from common pressure cylinder  10 , as shown in FIG. 7, or else rotation of sprocket wheels  44 ,  56  are stopped. Thereby, first and second chain gripper means  38 ,  42  have no connection with sheet  14  which is transferred by gripper  16  of common pressure cylinder  10 . 
     Next, function of above-described construction is detailed. In double-side printing (perfect printing) in which sheet  14  is reversed, two colors are printed on the surface of sheet  14  by first and second printing units  26 . Front end of sheet  14  is gripped by gripper  16  of common pressure cylinder  10  and, as shown in FIG. 2, reaches at opposing point of common pressure cylinder  10  against sprocket wheel  44  of first chain gripper means  38 . Front end of sheet  14  is then accepted by gripper  50  of first chain gripper means  38  and sheet  14  is transferred away from common pressure cylinder  10  with running of chain  48 . 
     Sheet  14  is transferred to upright direction along chain  48 . When rear end reaches at opposing point against perfecting cylinder  40 , as shown in FIG. 3, rear end is gripped by perfecting gripper  52  of perfecting cylinder  40 . 
     Then, as shown in FIG. 4, perfecting gripper  52  which gripped rear end of sheet  14  turns in accordance with rotation of perfecting cylinder  40 , thereby sheet  14  is reversed. 
     In FIG. 5, sheet  14  end (which was rear end before) is delivered to gripper  62  of second chain gripper means  42  at opposing point of perfecting cylinder  40  against second chain gripper means  42 . Substantial role of second chain gripper means  42  is to lead sheet  14  to common pressure cylinder  10  again and, as shown in FIG. 6, sheet  14  end is delivered to common pressure cylinder  10  at opposing point against sprocket wheel  56 . 
     Hereafter, third and fourth printing units  26  print on backside of sheet  14  and finally double-side printing of two colors on surface as well as two colors on backside is completed. 
     As described before in relation to FIG. 8, position of perfecting cylinder  40  is adjusted in parallel to first and second chain gripper means  38 ,  42  in compliance with sheet length. 
     Sheet perfecting apparatus according to the present invention has, as described with FIG. 7, no relation with sheet transfer path in one-side printing in which sheet reversing is not needed. 
     According to the present invention, double-side printing of, for example, two colors on surface as well as two colors on backside is possible by only one satellite-type printing press, as in the course of many printing units  26  which are provided in satellite-like manner around common pressure cylinder  10 , a plurality of chain gripper means  38 ,  42  are paralleled and these means  38 ,  42  are connected via perfecting cylinder  40 . The apparatus does not intervene in sheet transfer path in one-side printing in which sheet reversing is not needed, therefore, high register accuracy is secured. In addition, despite variety of sheet length, corresponding adjustment can easily be attained by the apparatus. 
     As detailed, sheet perfecting apparatus is very unique in its construction and can contribute to the progress of printing technique. 
     The present invention is not limited to the embodiment described hitherto. Various changes and modification can, of course, be made without departing from the spirit of the invention. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
       10  common pressure cylinder 
       14  sheet 
       16  gripper 
       26  printing unit 
       36  sheet perfecting apparatus 
       38  first chain gripper 
       40  perfecting cylinder 
       42  second chain gripper 
       50  gripper 
       52  perfecting gripper 
       62  gripper