Patent Publication Number: US-6341773-B1

Title: Dynamic sequencer for sheets of printed paper

Description:
FIELD OF THE INVENTION 
     The present invention relates to a dynamic sequencer for sheets of printed paper and more particularly to a dynamic sequencer for sheets of paper printed in two-up and slalom for being used in a files forming machine and comprising an input section for two sheets lying in a flanking relationship with respects to a longitudinal axis and a collecting station for collecting the superposed sheets. 
     BACKGROUND OF THE INVENTION 
     Generally, the files forming machines utilize laser printers, which, for reason of cost and velocity, print the data on continuous forms with perforated edges having the width of two flanked sheets. In fact, the cost of a laser printing for commercial purposes depends on the number of rows and not on their width. The sheets are printed together, as alternated couples, on the moving form and according to the method known as in “two-up” and “slalom.” A sequencer device separates the sheets by means of longitudinal and transversal cuts on the form and superimposes the individual sheets, in sequence, for the formation of the files in the established order. 
     A sequencer for sheets of paper printed in two-up is known in which the sheets separated from the continuous form are temporarily arrested in front of a conveyor belt disposed perpendicularly to and beneath the cutting station. Two solenoids are simultaneously actuated for pushing the sheets on the conveyor belt. Then, the belt superimposes the sheets, in the sense of the width, against stop elements of another conveyor belt. In view of the intermittent movement of the sheets, a sequencer of this type is relatively time-consuming in the forming of the files. Further, the transversal disposition of the conveyor belt is the cause of an excessive encumbrance of the files forming machine. 
     A known dynamic sequencer of printed sheets provides to engage the sheets with two deflectors after the separation from the form. The deflectors twist the sheets and upset them on a transversal conveyor belt for the collection of the file. This sequencer is quick but results rather expensive and bulky owing to he catching mechanism necessary to assuring a twisting without jams of the separated sheets. Further the files will result upset, with difficulties fin positioning data reading devices and rotated through 90° with respect to the axis of advancing , with difficulties in the operation of a following device. 
     SUMMARY OF THE INVENTION 
     The principal object of the present invention is therefore to provide a dynamic sequencer for two-up and slalom printed sheets to be used in files forming machines performing a high productivity and resulting of costs and dimensions relatively limited. 
     This object is achieved by the dynamic sequencer of the above mentioned type, comprising overlapping means for moving the sheets of a file from the input section to the collecting station along two respective trajectories, in which the overlapping means provides a transversal constant trim, and in which the trajectories of the sheets include at least a divergent portion divergent in height from the input section, at least an approaching portion for approaching, in projection, at least a sheet toward another sheet along the longitudinal axis and at least a concurrent portion for causing at least a sheet to be concurrent in height toward the collecting station in a superimposed relationship with another sheet of the file. 
     The characteristics of the invention will become clear from the following detailed description of a preferred embodiment given purely by way of non-limitative example with the aid of the accompanying drawings wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 represents a schematic plan view of a files forming machine including a dynamic sequencer for printed sheets according to the invention; 
     FIG. 2 shows a scheme of printing for the sheets of the sequencer of FIG. 1; 
     FIG. 3 shows a scheme representative of the formation of files according to the invention; 
     FIG. 4 shows a schematic plan view of the sequencer of the invention; 
     FIG. 5 represents a lateral view of the sequencer of FIG. 4; 
     FIG. 6 represents a schematic perspective view of the sequencer according to the invention; and 
     FIG. 7 represents a partial plan view of the device of Fig. 6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIG. 1, number  16  represents a portion of a machine for forming printed files, including a dynamic sequencer  17  according to the invention. 
     The files forming machine comprises a printer laser of known type disposed upstream of the portion  16  and not shown in the drawings, and an output conveyer belt  20 . 
     As for the present invention, a file  21  is constituted by a plurality of sheets  19 - 1 ,  19 - 2  . . .  19 - n  and the laser printer provides to print the content of all the sheets  19 - 1 ,  19 - 2  . . .  19 - n  on a continuous form  18  according to the technique known as “two-up” and “slalom.” 
     For example, a file  21  with six sheets can be printed on the form  18  in slalom, as represented in FIG. 2, in accordance with the order ( 6 ), ( 5 ), ( 4 ), ( 3 ), ( 2 ), ( 1 ) and in which the sheets  19 - 1 ,  19 - 2 ;  19 - 3 ,  194 ; and  19 - 5 ,  19 - 6  result in a flanking relationship. The sheets  19 - 1  to  19 - 6  can be also sequenced to define two files of three sheets to be printed in the order ( 6 ), ( 5 ) and ( 4 ) and ( 3 ), ( 2 ) and ( 1 ), respectively. 
     The dynamic sequencer  17  of the invention comprises an input section  22 , overlapping means  23 , and a collecting station  24 . The input section  22  is adjacent to the laser printer for separating two sheets  19 - a  and  19 - b  from the form  18  and disposing them in a flanging (two-up) relationship. The overlapping means  23 , guide and move the sheets up to an overlapping condition, and the collecting station  24  collects the files  21  and delivers them toward the output conveyer belt  20  of the machine. 
     Specifically, the input section  22  defines a longitudinal horizontal axis  27  and comprises a static and/or dynamic cutter means not shown in the drawings. The cutter means executes transversal and longitudinal cuts on the forms  18 , such to separate the sheets  19 - a  and  19 - b , each of a given width “W” and a length “L”. The form  18  unwinds along a horizontal axis parallel to the axis  27  and the section  22  provides to present the sheets  19 - a  and  19   b  on a horizontal support plane  26  at the sides of the longitudinal axis  27 . 
     In accordance with the invention the overlapping means  23  (FIGS. 3,  4  and  6 ) guide and move the sheets  19 - a ,  19 - b  from the input section  22  to the collecting station  24  along two respective trajectories  28 ,  29 . These trajectories cross in diagonal in the space and are such to maintain the sheets in a transversal trim substantially constant and horizontal. 
     The trajectories  28 ,  29  include divergent portions  31 ,  32 , approaching portions  33 ,  34  and concurrent portions  36 ,  37 . The divergent portions  31 ,  32  are divergent in height from the support plane  26 ; the approaching portions  33 ,  34  are of constant height and approach the sheets in diagonal toward a geometrical vertical surface passing through the longitudinal axis  27 ; and the concurrent portions  36 ,  37  are concurrent in height toward the collecting station  24 . 
     Suitably, the overlapping means  23  comprise a divergence unity  38 , a crossing unity  39  and a convergence unity  40  which are set in cascade along the axis  27  between the input section  22  and the collection station  24 . The divergence unity  38  is provided for guiding and moving the sheets  19 - a ,  19 - b  along the respective divergent portions  31 ,  32  of the trajectories  28 ,  29 ; the crossing unity  39  guides and moves the sheets along the approaching portions  33 ,  34 ; and the convergence unity  40  guides and moves the sheets along the concurrent portions  36 ,  37 . 
     The divergence unity  38  comprises two inclined planes  41  and  42  for guiding the sheets  19 - a  and  19 - b , respectively, and two extractors  43  and  44  disposed transversely to the support plane  26 . The inclined planes  41  and  42  pass through the divergent portions  31  and  32  and the extractors  43  and  44  are designed for engaging the sheets of the plane  26  and moving them along the planes  41  and  42 . The leading edges of these planes are aligned each other and adjacent to the extractors  43  and  44 , whilst the trailing edges are disposed at different heights, adjacent to respective horizontal movement surfaces  46  and  47 . These surfaces  46  and  47  are positioned one above the other, spaced apart a distance “H” in height, and pass through the approaching portions  33  and  34  of the trajectories  28 ,  29 . 
     The inclined plane  41  (see FIG. 5) is ascending with respect to the support plane  26  for dragging the sheet  19 -a on the movement surface  46  to a height “H/  2 ” above the support plane  26 . The inclined plane  42  is descending for dragging the sheet  19 - b  on the movement surface  47  to a height “H/ 2 ” under the plane  26 . 
     Upper guide elements  48 ,  49  are provided for guiding the sheets  19 - a ,  19 - b  along the inclined planes  41 , and  42 . For example, these elements  48 ,  49  are constituted by longitudinal gratings having capability of removal and which define with the planes  41  and  42  respective channels for the passage of the sheets  19 - a  and  19 - b.    
     The extractors  43  and  44  comprise each two motorized taking-up rollers and contrast rollers disposed between the support plane  26  and the leading edges of the inclined planes  41  and  42 . These extractors are designated for extracting the sheets  19 - a  and  19 - b  from the plane  26 , up to bring their leading edges close to the movement surfaces  46  and  47 . It is performed by maintaining a constant trim and with the longitudinal axes of the sheets lying on the planes passing through the divergent portions  31  and  32  of the trajectories  28  and  29 . 
     The couples of rollers of the extractors  43  and  44  are separately motorized and can be actuated either in synchronism or in sequence. In the first case, the sheets are moved in pair for forming files with an even number of sheet. In the case of actuating in sequence, one of the two sheets  19   a ,  19 - b  can be stopped whilst the other proceeds toward the collecting station  24  to define files with an odd number of sheets. 
     The crossing unity  39  comprises two groups of conveyer belts  51  and  52  suitably motorized and positioned at different heights. The groups of conveyer belts  51  and  52  are provided for dragging the sheets  19 - a  and  19 - b , respectively, and in which each conveyer belt has an upper and a lower section. The directions of motion of the two groups of conveyer belts are inclined in diagonal in the space and concurrent in plane toward a common direction corresponding, in projection, to the longitudinal axis  27 . Adjacent to the inclined planes  41  and  42 , the groups  51  and  52  extend for a width a few larger than “2W”. Adjacent to the unity  40 , these groups extend for a width a few larger than “W”. The length of the conveyer belts  51  and  52  is a few longer than he length “L” of the sheets  19 - a  and  19 - b.    
     In detail, the upper sections of the conveyer belts of the group  51  are tangent and define the movement surface  46  and are disposed at the sides of and parallel to the divergent portion  33  of the trajectory  28 . The upper sections of the belts of the group  52  are tangent and define the movement surface  47  and are disposed at the sides of and parallel to the portion  34  of the trajectory  29 . Furthermore, the direction of dragging of the conveyer belts of the group  51  and that of the belts of the group  52  result, in plane, symmetrically confluent toward the axis  27 . 
     The conveyer belts of the groups  51  and  52  are supported in independent way by respective input pulleys  53 ,  54  and exit pulleys  56 ,  57 . The input pulleys  53 ,  54  are adjacent to the trailing edges of the inclined planes  41  and  42 , and the exit pulleys  56 ,  57  are adjacent to an upper entry  58  and a lower entry  59 , respectively, of the convergence unity  40 . The pulleys of the groups  51 ,  52  have rotation axes lying on a horizontal plane, staggered with respect to the axes of the other pulleys and inclined with respect to the trailing edges of the planes  41  and  42 . 
     According to the represented form of execution of the invention, the conveyer belts of the groups  51  and  52  have an identical length. All the belts extend from the input pulleys  53 ,  54  to the exit pulleys  56 ,  57  through the entire approaching portions  33 ,  34  of the trajectories  28  and  29 . Also the pulleys  56 ,  57  have the respective rotation axes inclined and staggered each other and parallel to the axes of the input pulleys  53 ,  54  for a planar configuration of rhomboidal appearance. The conveyer belts  51 , 52  are motorized either in cascade among the pulleys  53 ,  54 , or by means of an intermediate motor roller engaged with the conveyer belts  51 ,  52 . 
     Two groups of contrast belts  61 ,  62  and respective pulleys  63  and  64 ;  66  and  67  are associated to the groups of conveyer belts  51 ,  52 . The groups  61  and  62  are specular with respect to the groups  51  and  52  and the pulleys  63  and  64 ;  66  and  67  are cinematically connected with the pulleys of the groups  51  and  52 . The sheets  19 - a ,  19 - b  can be positively dragged between the upper sections of the belts of he groups  51  and  52  and the lower sections of the belts of the groups  61  and  62 . 
     The pulleys and the conveyer belts of the groups  51 ,  52  are arranged under the movement surfaces  46  and  47  while the pulleys and the belts of the groups  61 ,  62  are ranged above these surfaces. The sheets will be engaged by the upper and lower sections of the conveyer and contrast belts tangent to the surfaces  46  and  47 . With this structure, the sheets  19 - a  and  19   b  are susceptible of movement along horizontal surfaces comprising the convergence portions  33  and  34 . It occurs with a minimum shifting of the sets firm the support plane  26 , without any deflection and stop and according to a law of motion substantially linear. 
     Suitably, the distance “H” is dimensioned in such a way to consent the pulleys  64  and  67  of the groups  61  and the pulleys  53  and  56  of the group  52  to be one above the other without any obstacle to the movement of the sheets  19 - a  and  19 - b.    
     The pulleys of the groups of belts  51 ,  61  and  52 ,  62  are supported by frames  68 ,  69  each having capability of adjustment by means of two screw-and-notch couplings  71 - a ,  72 - a  and  71 - b ,  72 - b  (FIG.  7 ). Thus, the inclination of the conveyer belts and their position with respects to the trailing edge of the support plane  26  and the entries  58  and  59  of the convergence unity  40  can be modified for an optimal dynamic superposition of the printed sheets. The frames with the respective groups of belts can be removed for the access to the movement surfaces of the sheets  19 - a  and  19 - b.    
     The convergence unity  40  includes two couples of guide planes  73  and  74  and contrast planes  76  and  77  and a couple of extraction rollers  78 ,  79 . The couples of planes  73 ,  76  and  74 ,  77  are descendant and ascendant, respectively, and are aligned with the entries  58  and  59 . These planes define two guided channels for the sheets  19 - a  and  19 - b , which are spaced the one with respect to the other and in a condition of overlapping. The channels are concurrent toward a common exit adjacent to the extractor rollers  78 ,  79 . The rollers provide to drag the sheets  19 - a ,  19 - b  from the exit of the channels and the surfaces  46  and  47  to the collecting station  24  along a direction of movement substantially coincident with the longitudinal axis  27 . 
     The guide planes  73  and  74  and the contrast planes  76  and  77  are laterally limited by two walls  81  and have capability of longitudinal adjustment with respect to the rollers  78 ,  79  for a dynamic optimal stacking of the printed sheets. For example, it is performed by screw-and-notch couplings  82 ,  83 . 
     The collecting station  24  comprises a supporting plane  80  and delivery means not shown in the drawings. The plane  80  is arranged at the entry of the collecting station  24  and is delimited by a longitudinal controlled arrest element  84  (see FIG. 4) and two lateral slide bars  86  and  87  for forming the file  21 . The sheets  19 - a ,  19 - b  superposed and in movement can be arrested by the element  84  and leveled in the file by the element  84  and the bars  86  and  87 . Thereafter, the delivery means will provide to deliver the formed file to the conveyer belt  2 . 0  of the machine. 
     The operation of the sequencer  17  is the following: 
     In the input section  22 , the form  18  is cut in manner to forming the flanked sheets  19 - a  and  19 - b  and presenting them on the support plane  26  against the extractors  43  and  44 . The motorized rollers move the sheets  19 - a  and  19 - b  longitudinally on the planes  42  and  41 , respectively salient and descending, maintaining the relation of flanking thereof and the transversal horizontal trim. 
     The sheets  19 - a  and  19 - b  are engaged by the leading edges of the belts of the groups  51  and  61  and the belts of the groups  52  and  62 , respectively, in synchronism with the extractors  43  and  44 . The conveyer belts drag the sheets on the surfaces  46  and  47  (see FIG. 3) in diagonal up to reaching, in projection, a condition of symmetry with respect to the longitudinal axis  27 . 
     In the case in which both the sheets  19 - a  and  19 - b  are moved together, these sheets will result in an overlapping relationship on the surfaces  46  and  47 . The movement of the sheets is linear and includes an approaching transversal component equal to the half of the width “W”. Then, the sheets  19 - a  and  19 - b  are pushed by the conveyer belts along the channels defined by the planes  73 ,  74  and the walls  81  toward the supporting plane  80  and against the arrest element  84 . The lower surface of the sheet  19 - a  will be superimposed on the upper surface of the sheet  19 - b , while the slide bars  86  and  87  level the edges of all the sheets. 
     If the files  21  include an odd number of sheets, for instance three sheets  19 - 1 ,  19 - 2  and  19 - 3  of the set of sheets  19 - 1  to  19 - 6 , the sequence of print on the sheets is ( 3 ), ( 1 ), ( 2 ). The sheets  19 - 1  and  19 - 2  are separated from the form and moved together as above described. The sheet  19 - 2  will be deposited on the supporting plane  80  and the sheet  19 - 1  will be superposed on the sheet  19 - 2 . 
     On the contrary, after the separation from the form of the sheets  19 - 3  and  194 , only the extractor  43  and the conveyer belts of the groups  53  and  63  are actuated. Thus the sheet  194  remains on the plane  26  and the sheet  19 - 3  is moved along the trajectory  28  and stacked over the sheet  19 - 1 . Thereafter, the formed file is delivered from the collecting station  24  to the conveyer  20 . 
     The forming of the other file requires the actuation of the extractor  44  and the conveyer belts of the groups  52  and  62 . The arrested sheet  19 - 4  will be moved along the trajectory  29  and deposited on the supporting plane  80 . Then, the sheets  19 - 5  and  19 - 6  are separated from the form  18  and moved together as above described. The sheet  19 - 6  will be deposited on the sheet  19 - 4 , the sheet  19 - 5  will be superpose on the sheet  19 - 6  and the formed file will be delivered to the conveyer  20 . 
     The dynamic sequencer of the invention results of high speed with the capability of collecting files having an even or an odd number of sheets and performing an accurate overlapping of the sheets. 
     Advantageously, the files are formed with the same disposition of the sheets used for the print. Therefore, the data on the first sheet of the file can be directly observed on the upper surface of the first sheet. Further, the files can be moved along the longitudinal axis of the sheets for a following enveloping process to be executed in a natural way. 
     In alternative to the continuous form, the dynamic sequencer  17  can use stacks of double width sheets fed by a suitable sheet feeder. In this case, the cutter of the input section  22  is simple and executes only the longitudinal cutting for the separation of the two sheets from the single double width sheet fed by the feeder. The sequencing of the sheets for the forming of the file results the same as for the sheets separated from the continuous form. A sequencer of his type is particularly useful for the forming of files of “A4” sized sheets derived from printed sheets fed by a feeder for “A3” sized sheets. 
     A sequencer  17  using a continuous form can provide a cutter of the input section  22  which, in addition to the longitudinal cutting, is adapted to execute transversal cuttings starting from the two sides of the form  18  and selectively limited to the width “W” for the separation of a single sheet. The unit  38  includes a single extractor with a motorized taking-up roller and contrast rollers for extracting either the two sheets  19 - a  and  19 - b  or the sole sheet  19 - a  or  19 - b  jointly or singularly separated from the form. 
     In the first case, the sheets are moved in pair. In the second case, the cutter separates a sole sheet and the motorized roller acts and moves the separated sheet whilst it slides without effect on the sheet attached to the form. The arrested sheet will be moved for the forming of the following files only after the actuating of the cutter and its separation from the form  18 . 
     As further alternatives, the divergence unity  38 , the crossing unity  39  and the convergence unity  40  can modify the trajectory of a sole sheet  19 - a  or  19 - b  for reaching the desired overlapping in the file. 
     In a second form of execution of the invention, not represented in the drawings, the conveyer and/or contrast belts of the groups  51 ,  61 ;  52 ,  62  have different lengths, scaled from the half of the portions of trajectory  33 ,  34  and split. A series of intermediate pulleys is added to the first and the second plurality of pulleys. The intermediate pulleys are fixed on a common motor axis disposed in a median position with respect to the pulleys  53 ,  54 ;  56 ,  57 . 
     Naturally, the principle of the disclosure remaining the same, the embodiments and the details of manufacture may be widely varied with respect to that described and illustrated by way of non-limitative example, without, by this, departing from the ambit of the present invention.