High Speed Sheet Feeder Sheet Spacing System and Method

Abstract

A document system and method of moving documents of a stack. The system operates to move documents by rotating a feed wheel and a transport wheel to move a document in a feed direction. The space between documents is maintained by controlling the speed of the feed wheel and the transport wheel independently.

What is claimed is: 
     
         1 . A document system for a document, including:
 a feed servo controller;   a feed servo motor controllable by the feed servo motor;   a feed wheel adjustably rotatable by the feeder servo motor to move the document in a feed direction;   a feed sensor downstream of the feed wheel in the feed direction and capable of detecting the presence of the document;   a transport servo controller;   a transport servo motor controllable by the transport servo controller;   transport wheels downstream of the feed wheel and the feed sensor in the feed direction, wherein at least one of the transport wheels is adjustably rotatable by the transport servo motor to continue to move the document in the feed direction;   a transport sensor downstream of one of the transport wheels in the feed direction and capable of detecting the presence of the document;   an encoder operably connected to a transport wheel to measure the length of the document; and   wherein the rotational speed of the feed wheel and the rotational speed of the transport wheels are controllable independently.   
     
     
         2 . The system of  claim 1 , further including a stack of documents. 
     
     
         3 . The system of  claim 1 , including two transport wheels connected together for rotation, one of the transport wheels capable of driving the other transport wheel. 
     
     
         4 . The system of  claim 1 , further including an accumulator for collecting the document after being fed by the transport wheels. 
     
     
         5 . The system of  claim 1 , wherein more than on transport wheel is adjustably rotatable by the transport servo motor. 
     
     
         6 . The system of  claim 1 , further including a processor and wherein the feed sensor produces an output signal indicative of the detection of the document. 
     
     
         7 . The system of  claim 6 , wherein the feed servo motor is controlled by the feed servo controller depending on the output signal from the feed sensor. 
     
     
         8 . The system of  claim 1 , further including a processor and wherein the transport sensor produces an output signal indicative of the detection of the document. 
     
     
         9 . The system of  claim 8 , wherein the transport servo motor is controlled by the feed servo controller depending on the output signal from the transport sensor. 
     
     
         10 . The system of  claim 1 , wherein the transport sensor is operably connected with the encoder such that an output signal of the transport sensor activates the encoder. 
     
     
         11 . The system of  claim 1 , wherein the feed wheel is rotatable at multiple predetermined speeds. 
     
     
         12 . The system of  claim 1 , wherein the transport wheels are rotatable at multiple predetermined speeds. 
     
     
         13 . The system of  claim 1 , the document further including a visual code, the system further including a scanner to detect the visual code. 
     
     
         14 . A method of moving documents of a stack, including:
 rotating a feed wheel to move a document in a feed direction;   rotating a transport wheel downstream of the feed wheel to continue to move the document in the feed direction;   rotating the feed wheel and the transport wheel to move additional documents; and   maintaining a space between the documents moving in the feed direction by controlling the speed of the feed wheel and the speed of the transport wheel independently.   
     
     
         15 . The method of  claim 14 , wherein rotating the feed wheel further includes rotating the feed wheel at a first feed speed to initiate moving a document in the feed direction to a first alignment point. 
     
     
         16 . The method of  claim 14 , further including:
 rotating the feed wheel at a first feed speed;   detecting the presence of a document at a first alignment point and then stopping the feed wheel;   rotating the feed wheel at a second feed speed that is faster than the first speed;   rotating the transport wheel at a first transport speed that is the same as the second feed speed; and   wherein maintaining the space between documents includes:
 determining if the document is at a predetermined position along the feed direction; and 
 if the document is not at the predetermined position, adjusting the speed of at least one of the feed to move the next document slower and wheel and the transport wheel to move the document faster. 
   
     
     
         17 . The method of  claim 16 , wherein adjusting the speed of at least one of the speed wheel and the transport wheel includes at least one of:
 decreasing the speed of the feed wheel to either the first feed speed or a third feed speed that is slower than the first feed speed and slower than the second feed speed; and   increasing the speed of the transport wheel to a second transport speed.   
     
     
         18 . The method of  claim 16 , wherein adjusting the speed of at least one of the speed wheel and the transport wheel is done after the document is past the feed wheel. 
     
     
         19 . The method of  claim 16  wherein determining if the document is at a predetermined position includes measuring the length of a document to pass the predetermined position. 
     
     
         20 . The method of  claim 16 , further including:
 determining if the document has moved past the first alignment point; and   if the document has moved past the first alignment point, rotating the feed wheel at the second feed speed and rotating the transport wheel at the first transport speed.   
     
     
         21 . The method of  claim 14 , including:
 determining the number of documents to move past the predetermined position;   if the number of documents is equal to or greater than a set count value:
 stopping the rotation of the transport wheel; 
 rotating the feed wheel at the first feed speed to move a document to a first alignment point; and 
 detecting the presence of a document at the first alignment point and then stopping the feed wheel. 
   
     
     
         22 . The method of  claim 14 , including:
 determining the number of documents to move past a predetermined position;   measuring the length of a document that has passed the predetermined location;   if the number of documents is less than a set count value, determining if a document is located at a first alignment point;   if no document is detected at the first alignment point:
 rotating the feed wheel at the second feed speed; and 
 rotating the transport wheel at the first transport speed; 
   determining if a document is located at the predetermined location;   if no document is detected at the predetermined location, determining if the measured length of the document is correct; and   if the measured length of the document is incorrect, initiating a system error routine and stopping both the feed wheel and the transport wheel.   
     
     
         23 . The method of  claim 22 , wherein:
 the documents include a visual code; and   if no document is detected at either the first alignment point or the predetermined location and if the measured length of the document is correct, scanning the visual code on a document to determine if a set error occurred;   if a set error occurred, initiating a system error routine and stopping both the feed wheel and the transport wheel.   
     
     
         25 . The method of  claim 14 , further including rotating the feed wheel at the second feed speed and rotating the transport wheel at the first transport feed after a document passes the first alignment point.