Patent Publication Number: US-7584958-B2

Title: Document stack leveling method, and a document finisher including the same

Description:
BACKGROUND OF THE INVENTION 
     Document finisher modules are known. Xerox has launched the Base Finisher Module, a finishing device with stacking (with and without offsetting), stapling (portrait, landscape and dual), and dual finishing (unload while run) capabilities. As depicted in  FIG. 1 , the architecture consists of an input transport  10 , compiler  50  and a stack tray  60  with a full capacity of 3,000 sheets. This capacity decreases as stack flatness deteriorates due to any of paper curl, waviness and staple thickness. The uneven stack growth caused by staple thickness creates the following problem and the need for this invention. 
     First, as to stack quality and productivity, the stack flatness rapidly deteriorates due to the cumulative effect of the staple thickness, significantly reducing the number of sheets and sets that can be stacked reliably. Currently small stapled sheets comprising 15 sheets or less are limited to low number of sets to minimize shutdowns. 
     Second, as to handling, the stack of stapled sets is unstable, making it very difficult to handle, store and package. 
     Thus, there is a need for the present invention. 
     BRIEF SUMMARY OF THE INVENTION 
     In a first aspect of the invention, there is provided a method for leveling a document stack comprising (a) providing a document stack leveling container for leveling a stack of one or more documents, each document having a document thick side that is thicker than the opposite document thin side, the document stack leveling container having generally-upright container sides defining an upper container mouth and an opposite container bottom, the document stack leveling container mouth and sides forming a container hollow, a document stack top surface leveling ramp disposed in the document stack leveling container hollow so an included ramp surface slopes downward from an included container shallow end towards the opposite included container deep end; and (b) disposing documents in the document stack leveling container to form a document stack therein with the included document thick sides generally proximate to the document stack leveling container deep end. 
     In a second aspect of the invention, there is provided a document finisher arranged for leveling a document stack in accordance with a method, the method comprising (a) providing a document stack leveling container for leveling a stack of one or more documents, each document having a document thick side that is thicker than the opposite document thin side, the document stack leveling container having generally-upright container sides defining an upper container mouth and an opposite container bottom, the document stack leveling container mouth and sides forming a container hollow, a document stack top surface leveling ramp disposed in the document stack leveling container hollow so an included ramp surface slopes downward from an included container shallow end towards the opposite included container deep end; and (b) arranging the document finisher to dispose documents in the document stack leveling container to form a document stack therein with the included document thick sides generally proximate to the document stack leveling container deep end. 
     In a third aspect of the invention, there is provided a method for leveling a document stack comprising (a) providing a container means for leveling a document stack of one or more documents, each document having a document thick side that is thicker than the opposite document thin side; and (b) disposing documents in the container means, thus forming a document stack therein; where the container means includes a bottom surface arranged such that an included document stack top surface is maintained substantially level. 
     In a fourth aspect of the invention, there is provided a document finisher arranged for leveling a document stack comprising container means for leveling a document stack of one or more documents, each document having a document thick side that is thicker than the opposite document thin side; and means for disposing documents in the container means, thus forming a document stack therein; where the container means includes a bottom surface arranged such that an included document stack top surface is maintained substantially level. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  depicts a document finisher module  100  in accordance with the prior art wherein the depicted document stack top surface  201  is NOT maintained substantially horizontal and level. 
         FIG. 2  depicts a document finisher module  1000  arranged with a document stack leveling container  300 . In accordance with the present invention, the depicted document stack stop surface  201  is maintained substantially horizontal and level. 
         FIG. 3  depicts the document stack leveling container  300  of  FIG. 2 . 
         FIG. 4  depicts a document stack  200 , including a depicted document stack top surface  201 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Briefly, in accordance with the present invention, a document finisher is arranged for forming a document stack whose top surface is maintained substantially level. The document finisher includes a document stack leveling container for containing a document stack of one or more documents. Each document has a document thick side that is thicker than the opposite document thin side. The document stack leveling container includes a hollow. The document finisher is arranged for disposing documents in the hollow, thus forming a document stack therein. The hollow includes a bottom shaped such that the document stack top surface is maintained substantially level. 
     Referring to  FIG. 4  the depicted document stack  200  comprises one or more documents  20 ,  20 ′. Each document  20 ,  20 ′ includes a document thick side  28 ,  28 ′ that is thicker than the corresponding opposite document thin side  24 ,  24 ′. Thus, the depicted document thick side  28 ,  28 ′ has a corresponding thickness  8 ,  8 ′ and the depicted opposite document thin side  24 ,  24 ′ has a corresponding thickness  4 ,  4 ′, where the document thick side  28 ,  28 ′ thickness  8 ,  8 ′ is greater than the document thin side  24 ,  24 ′ thickness  4 ,  4 ′. In one embodiment, the documents  20 ,  20 ′ comprise media sheets that are fastened near the document thick side  28 ,  28 ′. In  FIG. 4  suitable document fasteners are depicted by reference numbers  27 . 1 ,  27 . 2  and  27 . 3 . In one embodiment, the document thick side  28 ,  28 ′ thickness  8 ,  8 ′ is based on the presence of one or more document fasteners  27 . 1 ,  27 . 2  and  27 . 3 . In one embodiment, the media sheets are fastened with staples, thus forming stapled media sets. 
     Referring to  FIG. 1  during compiling the sheets  20  enter the compiler area  50  via the input transport  10 . After the full set is compiled it is dropped  3 ′ on the document stack  200  below. The maximum capacity of the document finisher module  100  is 3000 sheets. 
     As depicted in  FIG. 1 , for stapled sets a build-up of staples causes the document stack  200  to grow uneven and very unstable. Currently the stack height is limited for stapled sets with the worst-case being small sets, 15 sheets or less. 
     Referring to  FIG. 2 , the document stack leveling container  300  provides the necessary structure to allow the growth of the stapled set document stack  200 . In addition, the container  300  facilitates the handling of unstable stacks and may be used as a storage and shipping container. 
     Referring to  FIG. 3  there is depicted a document stack leveling container  300  wherein stapled sets may be stacked, stored and delivered. In various embodiments, the document stack leveling container contains a depicted sensor cutout  390  and depicted one or more clamp open notches  391 ,  392 , which set tray height. These optional features  390 ,  391 ,  392  enable the document stack leveling container  300  to interact with sensors and mechanisms within the  FIG. 2  finisher  1000  as it facilitates the required structure for stack growth. In addition the document stack leveling container  300  may serve as a ready-to-use storage carton, shipping carton, or both. A key benefit is there are no new sensors, electronics or software required to operate with the document stack leveling container. 
     As shown, the document stack leveling container  300  comprises generally-upright container sides  301 ,  302 ,  303 ,  304  defining an upper container mouth  310  and an opposite container bottom  320 . The container mouth  310  and sides  301 - 304  form a container hollow  330 . As shown, a document stack top surface leveling ramp  400  is disposed in the document stack leveling container hollow  330  so that an included ramp surface  401  slopes downward from an included container shallow end  340  towards the opposite included container deep end  380 . As shown, the ramp  400  comprises a ramp height  410  and a ramp bottom  430  sized such that the document stack top surface  201  depicted in  FIG. 2  is maintained substantially level. In one embodiment, the ramp surface  401  is inclined at an angle  420  so that each document  20  flows  9  down the ramp towards the container deep end  380 . 
     Referring now generally to  FIGS. 2-3 , there is provided the first aspect of the invention, namely, a method for leveling a document stack  200 . 
     Thus, in accordance with the first aspect, the document stack  200  is leveled by providing a document stack leveling container  300  for leveling a stack  200  of one or more documents  20 ,  20 ′; and disposing 3 documents  20 ,  20 ′ in the document stack leveling container  300  to form a document stack  200  therein with the included document thick sides  28 ,  28 ′ generally proximate to the document stack leveling container deep end  380 . As a result, the document stack top surface  201  is maintained substantially level. 
     In one embodiment, the above method includes providing a document finisher  1000  and arranging the document finisher for disposing the documents  20 ,  20 ′ in the document stack leveling container  300 . 
     In one embodiment, the document stack leveling container  300  is detachable from the document finisher  1000 . 
     In one embodiment, the document stack leveling container  300  comprises any of a storage carton and a shipping carton. 
     In one embodiment, the method includes providing a sensor cutout  390  in the document stack leveling container  300  bottom  320  near the document stack leveling container deep end  380 . 
     In one embodiment, the document stack leveling container  300  is comprised of cardboard. 
     In one embodiment, the method includes providing one or more clamp open notches  391 ,  392  in the mouth  310  proximate to the document stack leveling container deep end  380 . 
     Still referring generally to  FIGS. 2-3 , there is provided the second aspect of the invention, namely, a document finisher  1000  arranged for leveling a document stack  200  in accordance with a method. 
     Thus, in accordance with the second aspect, the method comprises providing a document stack leveling container  300  for leveling a stack  200  of one or more documents  20 ,  20 ′; and arranging the document finisher  1000  to dispose 3 documents  20 ,  20 ′ in the document stack leveling container  300  to form a document stack  200  therein with the included document thick sides  28 ,  28 ′ generally proximate to the document stack leveling container deep end  380 . As a result, the document stack top surface  201  is maintained substantially level. 
     Referring still generally to  FIGS. 2-3 , there is provided the third aspect of the invention, namely, a method for leveling a document stack  200 . 
     Thus, in accordance with the third aspect, the method comprises providing a container means  300  for leveling a document stack  200  of one or more documents  20 ,  20 ′; and disposing 3 documents in the container means, thus forming a document stack  200  therein; where the container means includes a bottom surface  401  arranged such that an included document stack top surface  201  is maintained substantially level. 
     In one embodiment, the above method includes providing a document finisher  1000  and arranging the document finisher for disposing the documents in the container means  300 . In one variation of this embodiment, the container means  300  is detachable from the document finisher  1000 . 
     Still referring generally to  FIGS. 2-3 , there is provided the fourth aspect of the invention, namely, a document finisher  1000  arranged for leveling a document stack. 
     Thus, in accordance with the fourth aspect, the document finisher  1000  comprises container means  300  for leveling a document stack  200 ; and means for disposing 3 documents in the container means, thus forming a document stack  200  therein; where the container means includes a bottom surface  401  arranged such that an included document stack top surface  201  is maintained substantially level. 
     In one embodiment, the container means  300  is detachable from the document finisher  1000 . 
     In summary, there is provided a document stack leveling container wherein stapled sets are stacked by a printer or copier. The document stack leveling container is placed on the output tray. The document stack leveling container includes a sloped bottom to accommodate stable build up on one edge or corner, and has cutout features that enable it to interact with sensors and mechanisms in the finisher to monitor tray position and stack height. Using the document stack leveling container, up to about 2000 sheets can be stacked, whereas without the document stack leveling container the limit is about 200 for 2-sheet sets, the worst case. The document stack leveling container is feasible to manufacture from cardboard. 
     The table below lists the drawing element reference numbers together with their corresponding written description: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 No.: 
                 Description: 
               
               
                   
                   
               
             
            
               
                   
                   1 
                 document travel path 
               
               
                   
                   3 
                 disposing document 
               
               
                   
                   3′ 
                 disposing document 
               
               
                   
                   4 
                 document thin side thickness 
               
               
                   
                   4′ 
                 document thin side thickness 
               
               
                   
                   8 
                 document thick side thickness 
               
               
                   
                   8′ 
                 document thick side thickness 
               
               
                   
                   9 
                 document flow 
               
               
                   
                  10 
                 input transport 
               
               
                   
                  20 
                 document 
               
               
                   
                  20′ 
                 document 
               
               
                   
                  24 
                 document thin side 
               
               
                   
                  27.1 
                 document fastener 
               
               
                   
                  27.2 
                 document fastener 
               
               
                   
                  27.3 
                 document fastener 
               
               
                   
                  28 
                 document thick side 
               
               
                   
                  50 
                 compiler 
               
               
                   
                  60 
                 stack tray 
               
               
                   
                  100 
                 document finisher module 
               
               
                   
                  200 
                 document stack 
               
               
                   
                  201 
                 document stack top surface 
               
               
                   
                  240 
                 document stack thin side 
               
               
                   
                  280 
                 document stack thick side 
               
               
                   
                  300 
                 document stack leveling container 
               
               
                   
                  301-304 
                 document stack leveling container sides 
               
               
                   
                  310 
                 document stack leveling container mouth 
               
               
                   
                  320 
                 document stack leveling container bottom 
               
               
                   
                  330 
                 document stack leveling container hollow 
               
               
                   
                  340 
                 document stack leveling container shallow end 
               
               
                   
                  380 
                 document stack leveling container deep end 
               
               
                   
                  390 
                 sensor cutout 
               
               
                   
                  391, 392 
                 clamp open notches 
               
               
                   
                  400 
                 ramp 
               
               
                   
                  401 
                 ramp surface 
               
               
                   
                  410 
                 ramp height 
               
               
                   
                  420 
                 ramp angle 
               
               
                   
                  430 
                 ramp bottom length 
               
               
                   
                 1000 
                 document finisher module 
               
               
                   
                   
               
            
           
         
       
     
     While particular embodiments have been described hereinabove, alternatives, modifications, variations, improvements and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications, variations, improvements and substantial equivalents.