Abstract:
This invention relates to a media multi-feed rejection apparatus, comprising: a plurality of feed rollers; a feed roller driving means operatively connected to one of the plurality of feed rollers; a clutch means operatively connected to the other of the plurality of feed rollers; and a single channel encoder means operatively connected to the clutch means to measure a rotation of the other of the plurality of feed rollers.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a media multi-feed rejection apparatus, comprising: a plurality of feed rollers; a feed roller driving means operatively connected to one of the plurality of feed rollers; a clutch means operatively connected to the other of the plurality of feed rollers; and a single channel encoder means operatively connected to the clutch means to measure a rotation of the other of the plurality of feed rollers. 
     2. Description of the Related Art 
     Double feeding of media is not desirable because the printing mechanism will assume that the at least two sheets of media are one sheet of media and print the image across both sheets of media. Also, the double feeding of media may create a media jam in the media handling mechanism. Prior to the present invention, as set forth in general terms above and more specifically below, it is known, in the media handling art to employ a variety of techniques to prevent double feeding of media. Such techniques include various sensors along the media handling path that are used to detect double feeding of media. Also, various mechanisms are utilized to interact with the media in order to prevent double feeding of media. While such systems have met with a modicum of success, none of these systems employ an encoder that monitors the rotation of a counter-rotating roller during the multi-feed rejection process in order to determine the shortest time required to eliminate all excess sheets. Consequently, a more advantageous media double feeding elimination system, then, would be provided if an encoder that monitors the rotation of a counter-rotating roller during the multi-feed rejection process is utilized to determine the shortest time required to eliminate all excess sheets. 
     It is apparent from the above that there exists a need in the art for a velocity mode encoder that is used to determine the optimum time to stop a multi-feed rejection process on a counter-rotating roller feed system. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure. 
     SUMMARY OF THE INVENTION 
     Generally speaking, an embodiment of this invention fulfills these needs by providing a media multi-feed rejection apparatus, comprising: a plurality of feed rollers; a feed roller driving means operatively connected to one of the plurality of feed rollers; a clutch means operatively connected to the other of the plurality of feed rollers; and a single channel encoder means operatively connected to the clutch means to measure a rotation of the other of the plurality of feed rollers. 
     In certain preferred embodiments, one of the plurality of feed rollers is comprised of a counter-rotating tire. Also, the feed roller driving means is further comprised of a motor. Also, the clutch means is further comprised of slip torque clutch. Also, the clutch means is operatively connected to the feed roller driving means. Finally, the single channel encoder means is further comprised of a velocity mode only encoder. 
     In another further preferred embodiment, a single channel encoder is used to determine the optimum time to stop a multi-feed rejection process on a counter-rotating roller feed system by monitoring the rotation of a counter-rotating roller during the multi-feed rejection process to determine the shortest time required to eliminate all excess sheets. 
     The preferred media multi-feed rejection apparatus, according to various embodiments of the present invention, offers the following advantages: ease-of-use; reduced power consumption; reduced power dissipation; reduced noise; reduced mechanical wear; decreased likelihood of media multi-feed; and reduced time to determine the shortest time required to eliminate all excess sheets. In fact, in many of the preferred embodiments, these factors of reduced power consumption, reduced power dissipation, reduced noise, reduced mechanical wear, decreased likelihood of media multi-feed, and reduced time to determine the shortest time required to eliminate all excess sheets are optimized to an extent that is considerably higher than heretofore achieved in prior, known media multi-feed rejection systems. 
     The above and other features of the present invention, which will become more apparent as the description proceeds, are best understood by considering the following detailed description in conjunction with the accompanying drawings, wherein like characters represent like parts throughout the several views and in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of an optimized multi-feed rejection apparatus, according to one embodiment of the present invention; 
         FIG. 2  is a schematic illustration of the optimized multi-feed rejection apparatus with the encoded counter-rotating roller, according to another embodiment of the present invention; 
         FIG. 3  is another schematic illustration of the optimized multi-feed rejection apparatus, according to another embodiment of the present invention; 
         FIG. 4  is a schematic illustration of the optimized multi-feed rejection apparatus, wherein a media multi-feed is prevented, according to another embodiment of the present invention; and 
         FIG. 5  is a schematic illustration of the optimized multi-feed rejection apparatus, wherein a media multi-feed is not present, according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference first to  FIG. 1 , there is illustrated one preferred embodiment for use of the concepts of this invention. As shown in  FIG. 1 , media multi-feed rejection apparatus  2  is illustrated. Apparatus  2  includes, in part, upper feed roller  4 , lower feed roller  6 , upper feed roller drive shaft  8 , upper feed roller drive gear  10 , lower drive gear  12 , lower drive shaft  14 , drive motor  16 , and lower feed roller drive gears  18 ,  20 . Lower feed roller  6 , preferably, is any suitable counter-rotating feed roller. Drive motor  16 , preferably, is any suitable motor that is capable of rotating the various elements of apparatus  2 . 
     With respect to  FIG. 1 , drive motor  16  is operatively connected to lower drive shaft  14 . Lower drive shaft  14  is operatively connected to lower drive gear  12 . Lower drive gear  12  is operatively connected to upper feed roller drive gear  10 . Upper feed roller drive gear  10  rotates to cause upper feed roller drive shaft  8  and upper feed roller  4  to rotate. Also,. lower drive gear  12  is operatively connected to lower feed roller drive gears  18 ,  20  to cause lower feed roller  6  to rotate, as will be described below. It is to be understood that upper feed roller  4  and lower feed roller  6  are located with respect to each other so as to feed a sheet of media  100  ( FIG. 4 ) from the media stack towards the printing mechanism (not shown). 
     With respect to  FIG. 2 , apparatus  2  further includes drive gear  50 , drive gear  52 , drive shaft  53 , conventional slip torque clutch  54 , drive shaft  55 , single channel encoder  56 , lower feed roller drive shaft  58 , and lower feed roller drive shaft bracket  60 . Slip torque clutch  54 , preferably, is any suitable clutch that allows lower feed roller  6  to counter-rotate and prevent lower feed roller  6  from rotating in the opposite direction. Also, single channel encoder  56 , preferably, is any suitable velocity mode only encoder that is capable of reading any component directly coupled to lower feed roller  6 , such as gear teeth or a film or shutter wheel encoder disk. 
     As shown in  FIG. 2 , lower drive gear  12  ( FIG. 1 ) is operatively connected to lower feed roller drive gears  18 ,  20 . Drive gear  50  is rotationally connected to lower feed roller drive  18 . Drive gear  50  interacts with drive gear  52 . Drive gear  52  is rotationally connected to drive shaft  53 . Drive shaft  53  interacts with conventional slip torque clutch  54 . Conventional slip torque clutch  54  interacts with drive shaft  55 . Drive shaft  55  is rotationally connected to single channel encoder  56 . Lower feed roller drive gear  18  is operatively connected to lower feed roller drive gear  20 . Lower feed roller drive gear  20  is rotationally connected to lower feed roller drive shaft  58 . Lower feed roller drive shaft  58  is retained in place by lower feed roller drive shaft bracket  60 . Finally, lower feed roller drive shaft  58  is operatively connected to lower feed roller  6 . 
     With respect to  FIGS. 3-5 , the spaced relationship (nip) between upper feed roller  4  and lower feed roller  6  are more clearly illustrated and will be discussed in more detail below. 
     With respect to  FIGS. 1-5 , the operation of multi-feed media rejection apparatus  2  will now be discussed. Drive motor  16  is operated at a constant speed to induce separation between sheets of media  100  and  102  ( FIGS. 4 and 5 ) being pulled off of a stack of media (not shown). Drive motor  16  causes upper feed roller  4  to rotate in the direction of arrow A ( FIGS. 3 and 4 ) to cause the media  100  to be transported from the media stack towards the printing mechanism. At the same time, drive motor  16  drives the input of the slip torque clutch  54  that causes lower feed roller  6  to rotate. In this manner, lower feed roller  6  will rotate only if two or more sheets of media  100  and  102  are present in the nip between upper feed roller  4  and lower feed roller  6  because the staged upper sheet of media  100  ( FIG. 4 ) is stalled by the locked upper feed roller  4  ( FIG. 4 ). If the lower feed roller  6  contacts the stalled upper sheet of media  100 , lower feed roller  6  will grip that sheet of media and stop, as well ( FIG. 5 ). It is to be understood that the torque and contact force of the lower feed roller  6  are designed to separate the two sheets of media  100  and  102  ( FIG. 4 ) from each other but grip to any media surface, even if only one sheet of media  100  ( FIG. 5 ) is present. If the lower feed roller  6  contacts the lower sheet of media  102  of a media multi-feed from the stack of media, the counter-rotating nature of lower feed roller  6  along the direction of arrow B ( FIGS. 3 and 4 ) will cause the lower sheet of media  102  to be rejected or otherwise transferred back towards the stack of media and allow only the upper sheet of media  100  to be transported towards the printing mechanism. 
     As discussed above, during a specific multi-media feed separation sequence, drive motor  16  is operated at a constant speed to induce separation of the multi-media feed. Encoder  56  is conventionally sampled and a velocity of lower feed roller  6  is determined. The velocity of lower feed roller  6  is conventionally compared against a target value. If the velocity of lower feed roller  6  is above the target value, it can be assumed that a multi-media feed separation is being performed and should be allowed to continue. Conversely, if the velocity of lower feed roller  6  is below the target value, it can be assumed that no multi-media feed is present at the nip between upper feed roller  4  and lower feed roller  6 . It is to be understood that a maximum time limit may be imposed on how long the velocity of lower feed roller  6  can be maintained above the target value. If the maximum time limit is exceeded, multi-feed media rejection apparatus  2  is checked/observed to determine if excessive slippage is occurring at the nip between upper feed roller  4  and lower feed roller  6 . 
     It is to be understood that the present invention can be embodied in any computer-readable medium for use by or in connection with an instruction-execution system, apparatus or device such as a computer/processor based system, processor-containing system or other system that can fetch the instructions from the instruction-execution system, apparatus or device, and execute the instructions contained therein. In the context of this disclosure, a “computer-readable medium” can be any means that can store a program for use by or in connection with the instruction-execution system, apparatus or device. The computer-readable medium can comprise any one of many physical media such as, for example, electronic, magnetic, or semiconductor media. More specific examples of a suitable computer-readable medium would include, but are not limited to, a portable magnetic computer diskette such as floppy diskettes or hard drives, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory, or a portable compact disc. It is to be understood that the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a single manner, if necessary, and then stored in a computer memory. 
     Those skilled in the art will understand that various embodiment of the present invention can be implemented in hardware, software, firmware or combinations thereof. Separate embodiments of the present invention can be implemented using a combination of hardware and software or firmware that is stored in memory and executed by a suitable instruction-execution system. If implemented solely in hardware, as in an alternative embodiment, the present invention can be separately implemented with any or a combination of technologies which are well known in the art (for example, discrete-logic circuits, application-specific integrated circuits (ASICs), programmable-gate arrays (PGAs), field-programmable gate arrays (FPGAs), and/or other later developed technologies. In preferred embodiments, the present invention can be implemented in a combination of software and data executed and stored under the control of a computing device. 
     It will be well understood by one having ordinary skill in the art, after having become familiar with the teachings of the present invention, that software applications may be written in a number of programming languages now known or later developed. 
     Once given the above disclosure, many other features, modifications or improvements will become apparent to the skilled artisan. Such features, modifications or improvements are, therefore, considered to be a part of this invention, the scope of which is to be determined by the following claims.