Abstract:
A gathering device for gathering books is provided including a gathering conveyor for transporting a book, a variable static charging unit having a voltage output providing a static charge to the book on the gathering conveyor and a controller connected to the variable static charging unit, the controller controlling the voltage output of the variable static charging unit.

Description:
[0001]     This claims the benefit of U.S. Provisional Application No. 60/838,636, filed on Aug. 18, 2006 and hereby incorporated by reference herein. 
     
    
     BACKGROUND  
       [0002]     Gathering devices such as perfect binders, saddle stitchers and mailroom inserters may use hoppers or feeders to collect sheet material. A saddle stitcher or perfect binder may for example collect folded printed materials fed from hoppers or feeders onto a saddle or perfect binder conveyor, respectively, to form a magazine or other printed product. In the context of the present application, the term hopper and feeder are used synonymously.  
         [0003]     U.S. Pat. No. 6,267,225 purportedly discloses a device for conveying thin workpieces for machines used in the printing technology field having at least one movable conveying element having an electrically insulating contact surface supporting at least one workpiece as it is being conveyed.  
         [0004]     U.S. Pat. No. 6,616,134 discloses a device for electrostatically charging a multilayer material web includes electrostatic charge elements assigned to outer sides of the multilayer material web, the charge elements being disposed upline of an inlet of the multilayer material web into a cylinder.  
         [0005]     U.S. Publication No. 2006/0180697 purportedly discloses an electrostatic charging system holds a film web to a roll without significant slippage, thus allowing for proper tension control of the web even with extreme differences in tension upstream and downstream of the motorized roll.  
       SUMMARY OF THE INVENTION  
       [0006]     In accordance with an embodiment of the present invention, a gathering device for gathering books includes a gathering conveyor for transporting a book and a variable static charging unit. The variable static charging unit has a voltage output providing a static charge to the book on the gathering conveyor. A controller connected to the variable static charging unit is provided. The controller controls the voltage output of the variable static charging unit. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     A preferred embodiment of the present invention will be elucidated with reference to the drawings, in which:  
         [0008]      FIG. 1  shows a front view of a section of a gathering device according to the present invention;  
         [0009]      FIG. 2  shows a top view of the  FIG. 1  embodiment; and  
         [0010]      FIG. 3  shows linear pinners. 
     
    
     DETAILED DESCRIPTION  
       [0011]     Sheets of gathered books may separate at high speeds as the sheets move down a gathering conveyor, for example, a gathering chain. Typically, a static charge can be induced into the book to prevent separation. However, too much static can pin the sheets to, if provided, steel sheet guides, and too little static can cause pages of the books to separate.  
         [0012]      FIGS. 1 and 2  show a gathering device  200  in accordance with an embodiment of the present invention. Gathering device  200  includes a hopper  40 , a gathering conveyor, for example, a gathering chain  30 , a static charging unit  50  and books  20  being transported on gathering chain  30  in a direction of travel X. Sheet guides  12  guide books  20  traveling on gathering chain  30 . More than one hopper  40  may be provided as desired.  
         [0013]     Pinners, for example, linear pinners  10 ,  10 ′, are positioned to apply a static charge to books  20  and are connected to static charging unit  50 . As shown in  FIGS. 2 and 3 , linear pinner  10 , may be mounted, for example, on a side of gathering chain  30  and linear pinner  10 ′ may be mounted on an opposite side of gathering chain  30 . Thus, a static charge may be applied to both sides of books  20 .  
         [0014]     The amount of static charge introduced into books  20  is a combination of a voltage output by charging unit  50  and a duration of time books are under linear pinners  10  receiving a static charge. Controller  100  adjusts the voltage output of static charging unit  50  according to the actual speed of gathering chain  30 . The amount of static charge applied to books  50  is adjusted for starts, stops and speed changes of gathering chain  30 . When gathering chain  30  stops and starts in order to, for example, clear a jam, controller  100  adjusts the voltage output of static charging unit  50  to adjust the static charge applied to books  20 . Thus, the static charge applied to books  20  is varied accordingly to the speed of gathering chain  30 .  
         [0015]     In this embodiment, a machine controller  100  controls a speed of gathering chain  30  and a voltage output of static charging unit  50 . Alternatively, the controller may not control the speed of gathering conveyor and may, for example, only control the static charging unit.  
         [0016]     Pinners  10 ,  10 ′ receive voltage output from static charging unit  50  and transmit a static charge to book  20 . Controller  100  varies voltage output of static charging unit  50  so a proper static charge is supplied to book  20  by linear pinners  10 ,  10 ′. A proper static charge is a static charge that does not result in pinning of books  20  to sheet guides  12 . The proper static charge may be the maximum charge which does not result in pinning or less than the maximum charge. Furthermore, the desired static charge may be greater than or equal to the charge required to keep pages of the books from separating. The proper static charge may be adjusted as desired by the operator or specifications of a given job.  
         [0017]     The controller may determine the speed of gathering conveyor in any suitable manner. The controller may determine the speed, for example, from an encoder on a motor driving the gathering conveyor, from other sensors on the gathering device, or by monitoring the actual speed in another way. Furthermore, the controller may determine the speed of the gathering conveyor from, for example, a speed set for the gathering conveyor at a user interface.  
         [0018]     The amount of static voltage provided may be, for example, a function of the book materials or size, the speed of the conveyor, the types and materials of the sheet guides provided, and may be based on predetermined tables or operator knowledge. Moreover, the amount of static charge can be varied as speed varies. By controlling the amount of static charge applied to books, reduced paper jams and improved book quality may result.  
         [0019]     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.