Mechanism and method of multiple documents feeding detection

Abstract

The present invention provides a multiple documents feeding detection mechanism includes an advancing roller applying a driving torque, a retarding roller applying a resisting torque and connected to the advancing roller for transporting pieces of documents, and a detecting means. The friction of a surface of the advancing roller, the friction of a surface of the retarding roller, the driving torque and the resisting torque are tuned to urge the retarding roller either into rotation while one signal document fed into a nip between the advancing roller and the retarding roller, or in standstill while multiple document fed into the nip. The detecting means determines whether the multiple documents feeding is caused by monitoring an action of the retarding roller.

1 . A multiple documents feeding detection mechanism, comprising:
 a driving means;   an advancing roller driven by the driving means;   a retarding roller being against the advancing roller for transporting one piece of document therebetween;   a clutch providing a resisting torque to the retarding roller; and   a detecting means monitoring an action of the retarding roller for determining multiple documents being fed into a nip between the advancing roller and the retarding roller;   wherein the friction coefficient of a surface of the advancing roller is greater than the friction coefficient of a surface of the retarding roller, and the friction coefficient of the surface of the retarding roller is greater than the friction coefficient of the fed documents,   wherein if the multiple documents are fed into the nip, then the friction of the surface of the retarding roller-to-the document will be greater than the friction between the documents to remain the retarding roller be in standstill.   
     
     
         2 . The multiple documents feeding detection mechanism as claimed in  claim 1 , wherein the detecting means comprises a disk, at least a through hole penetrating the disk, a shaft coaxially interconnecting the retarding roller and the disk, a light source located at one side of the disk and aligned with the through hole, a sensor located at the other side of the disk and aligned together with the light source and the through hole, and a processor connected to the sensor. 
     
     
         3 . The multiple documents feeding detection mechanism as claimed in  claim 1 , wherein the detecting means comprises a disk having staggered a low reflecting portion and a high reflecting portion on one surface thereof, a shaft coaxially interconnecting the retarding roller and the disk, a light source and a sensor located at the same side of the disk and facing the high reflecting portion and the low reflecting portion, and a processor connected to the sensor. 
     
     
         4 . The multiple documents feeding detection mechanism as claimed in  claim 3 , wherein the low reflecting portion is made of a black material, the high reflecting portion is made of a white material. 
     
     
         5 . A multiple documents feeding detection method, comprising:
 providing an advancing roller applied a driving torque;   providing a retarding roller applied a resisting torque less than the driving torque, and against the advancing roller for transporting one piece of document;   monitoring an action of the retarding roller by a detecting means to detect whether the multiple documents being fed into a nip between the advancing roller and the retarding roller;   wherein the friction coefficient of a surface of the advancing roller is greater than the friction coefficient of a surface of the retarding roller, and the friction coefficient of the surface of the retarding roller is greater than the friction coefficient of the fed documents,   wherein if multiple documents are fed into the nip, then the friction of the surface of the retarding roller-to-the document is greater than the friction between the documents to remain the retarding roller be in standstill.   
     
     
         6 . The method as claimed in  claim 5 , further comprises:
 providing a disk acted with the retarding roller, an obstructing portion and a penetrating portion formed on the disk;   locating a light source at one side of the disk, locating a sensor at the other side of the disk, the light source and the sensor aligned with each other, and aligned together with the penetrating portion of the disk;   connecting a processor to the sensor;   wherein if the sensor receives a beam from the light source alternately radiating through the penetrating portion and then obstructed by the obstructing portion of the disk, then the processor determines that there is only one single document fed into the nip; if the sensor receives the beam from the light source constantly radiating through the penetrating portion of the disk or constantly obstructed by the obstructing portion of the disk, then the processor determines there are multiple documents fed into the nip.   
     
     
         7 . The multiple documents feeding detection method as claimed in  claim 6 , wherein said beam radiated from said light source is one of a visible beam and an invisible beam. 
     
     
         8 . The method as claimed in  claim 6 , wherein if the beam radiating through the penetrating portion and obstructed by the obstructing portion of the disk alternately, then the sensor sends out a continuous pulse to the processor for determining that there is one single document fed into the nip; if the beam obstructed by the obstructing portion constantly due to standstill of the disk, then the sensor sends out a first potential signal to the processor for determining there are multiple document fed into the nip; if the beam radiating through the penetrating portion constantly due to the standstill of the disk, then the sensor sends out a second potential signal to the processor for determining there are multiple documents fed into the nip. 
     
     
         9 . The method as claimed in  claim 8 , wherein the first potential signal is a low potential signal and the second potential signal is a high potential signal. 
     
     
         10 . The method as claimed in  claim 5 , further comprises:
 providing a disk acted with the retarding roller, a low reflecting portion and a high reflecting portion formed on the disk;   locating a light source radiating a beam, and a sensor at one side of the disk;   connecting a processor to the sensor;   wherein while the sensor receives a variable intensity of the beam reflected by the high reflecting portion and then be absorbed by the low reflecting portion of the disk repeatedly due to movement of the disk, the processor determines that there is only one single document fed into the nip;   wherein the processor determines multiple document are fed into the nip while the sensor receives a constant intensity of the beam reflected by one of the low reflecting portion and the high reflecting portion of the disk.   
     
     
         11 . The method as claimed in  claim 10 , wherein the sensor sends out a continuous pulse signal to the processor according to the received variable intensity of the beam, and then the processor determines that there is only one single document fed into the nip according to received continuous pulse signal; wherein the sensor sends out a constant signal to the processor according to the received constant intensity of the beam, and then the processor determines multiple document fed into the nip according to received constant signal. 
     
     
         12 . The method as claimed in  claim 10 , wherein the high reflecting portion is made of a white material, the low reflecting portion is made of a black material. 
     
     
         13 . A multiple documents feeding detection mechanism, comprising:
 an advancing roller having a surface with a first friction coefficient;   a driving mean providing a driving torque to the advancing roller;   a retarding roller having a surface with a second friction coefficient, against the advancing roller for transporting one piece of document with a third friction coefficient;   a clutch providing a resisting torque to the retarding roller, the resisting torque being less than the driving torque, if there are multiple documents fed into the nip, then the retarding roller remains in standstill;   a disk driven into action with the retarding roller, having a first tuning portion and a second tuning portion;   a source radiating a beam to the disk;   a sensor sending a first signal according to a received variable intensity of the beam radiated from the source and then alternately tuning by the first tuning portion and the second tuning portion due to movement of the disk, and sending a second signal according to a received constant intensity of the beam radiated from the source and then tuning by one of the first tuning portion and the second tuning portion due to standstill of the disk; and   a processor connected to the sensor, determining multiple documents fed into the nip according to a received second signal from the sensor, and determining that there is one single document fed into the nip according to a received first signal from the sensor.   
     
     
         14 . A multiple documents feeding detection method, comprising:
 providing an advancing roller;   applying a driving torque to the advancing roller;   providing a retarding roller against the advancing roller for transporting one piece of document;   applying a resisting torque to the retarding roller;   setting the friction coefficient of a surface of the advancing roller be greater than the friction coefficient of a surface of the retarding roller, the driving torque be greater than the resisting torque, to urge the retarding roller into rotation when only one single document fed into a nip between the advancing roller and the retarding roller, and urge the retarding roller be in standstill when multiple documents fed into the nip;   providing a disk with a first tuning portion and a second tuning portion, driven into action with the retarding roller;   radiating a beam to the disk;   determining there is one single document fed into the nip according to a received variable intensity of the beam alternately tuned by the first tuning portion and the second tuning portion due to the movement of the disk;   determining that there are multiple documents fed into the nip according to a received constant intensity of the beam tuned by one of the first tuning portion and the second tuning portion due to standstill of the disk.