Abstract:
Embodiments of the present invention relate to an apparatus (i.e. an automatic teller machine) comprising an optical sensor. The optical sensor is configured to detect thickness of paper. Advantages of some embodiments of the present invention are that by determining a thickness of paper, it can be confirmed that two pieces of paper are not stuck together. For example, if two substantially identical pieces of paper are stuck together, then their thickness will be approximately twice the thickness of a single sheet. Accordingly, upon detection of two or more sheets of paper stuck together, a device, that automatically handles paper, may cause the sheets of paper to be separated.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to detecting thickness of paper.  
           [0003]    2. Background of the Related Art  
           [0004]    Devices that automatically handle paper (i.e. photocopy machines) are commonplace. These devices are useful, so that large amounts of paper can be handled efficiency and effectively (i.e. making a photocopy of a large document). Devices that handle paper must have mechanisms that replicate manual handling of paper. For example, photocopy machines have feeders for moving paper, sheet by sheet.  
           [0005]    A normal manual function of handling paper is for a person to use their hands to confirm that two sheets of paper are not stuck together. This is important, as if two sheets of paper are stuck together, paper may be wasted or inaccurately dispensed. If devices that automatically handle paper do not confirm if two sheets of paper are stuck together, then these devices may be ineffective in accurately automatically handling paper. Accordingly, there has been a long felt need for devices that automatically handle paper to confirm that two sheets of paper are not stuck together. Further, there has been a long felt need for this confirmation to be accomplished at a reasonable price.  
         SUMMARY OF THE INVENTION  
         [0006]    Objects of the present invention at least include overcoming the disadvantages of the related art. Embodiments of the present invention relate to an apparatus (i.e. an automatic teller machine) comprising an optical sensor. The optical sensor is configured to detect thickness of paper. Advantages of some embodiments of the present invention are that by determining a thickness of paper, it can be confirmed that two pieces of paper are not stuck together. For example, if two substantially identical pieces of paper are stuck together, then their thickness will be approximately twice the thickness of a single sheet. Accordingly, upon detection of two or more sheets of paper stuck together, a device, that automatically handles paper, may cause the sheets of paper to be separated.  
           [0007]    In embodiments, the optical sensor comprises a light source, a light detector, and an interference substrate. The light detector is configured to receive light from the light source. The interference substrate is configured to change a quantity of light received at the light detector according to the thickness of a sheet of paper. For example, the light source may be directed to the light detector. The interference substrate may be movable and place in the light path between the light source and the light detector. Movement of the interference substrate may effect the amount of light received at the light detector. Further, movement of the interference substrate may correspond to the thickness of a sheet of paper. Accordingly, the thickness of a sheet of paper may be determined by the amount of light received at the light detector.  
           [0008]    Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is an exemplary view illustrating construction of a thickness measuring apparatus.  
         [0010]    [0010]FIG. 2 is an exemplary view illustrating construction of a rotational displacement detecting apparatus and a thickness measuring apparatus.  
         [0011]    [0011]FIG. 3 is an exemplary conceptual view illustrating an operation of a rotational displacement detecting apparatus.  
         [0012]    [0012]FIGS. 4 and 5 are exemplary conceptual views illustrating an operation of a rotational displacement detecting apparatus using a light transmission member with a slit. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0013]    Automatic teller machines (ATM), photocopiers, and printers may include a plurality of conveyance rollers and/or idle rollers which can withdraw medium such as bills, copy papers and print papers one by one from a cassette and convey it to a follow-up device. Thickness measuring devices may be provided at one side of a conveyance roller to measure thickness of a passing medium. The passing medium may be passed between a conveyance roller and an idle roller after being withdrawn from a corresponding cassette so as to check if the medium is double conveyed (i.e. to check whether two sheets are stuck together).  
         [0014]    [0014]FIG. 1 is an exemplary illustration of embodiments of the present invention including a conveyance unit including a conveyance roller  11  and/or an idle roller  13  installed to be rotatable at an idle rotational shaft  14  parallel to a conveyance rotational shaft  12  of the conveyance roller  11  and accessible to and isolated from the conveyance roller  11 , so as to convey the medium  10  together with the conveyance roller  11 . The conveyance unit may include a measuring shaft  17  and a first rotary arm  19 . Measuring shaft  17  may be installed parallel to idle rotational shaft  14 . One end of first rotary arm  19  may be fixed at idle rotational shaft  14 . The other end of first rotary arm  19  may be fixed at measuring shaft  17  so that the idle rotational shaft  14  is rotated centering around the measuring shaft  17  when the medium  10  passes between the convey roller  11  and the idle roller  13 . Second rotary arm  21  may be rotated according to rotation of measuring shaft  17  by being extended along a radial direction of the measuring shaft  17 . Body  31  may be installed near an end portion of second rotary arm, so as to be rotatable centered around a rotational shaft  32  installed parallel to the measuring shaft  17 . Hooking jaw  34  may be formed spaced apart from rotational shaft  32  so that body  31  may be rotated in a state of being in contact with second rotary arm  21  when second rotary arm  21  is rotated by the measuring shaft  17 . Rotational displacement detecting unit  35  may be coupled at rotational shaft  32  of the body  31  and may detect a rotational displacement of body  31 .  
         [0015]    When medium  10  is inserted between conveyance roller  11  and idle roller  13 , idle roller  13  may be moved from conveyance roller  11  a distance corresponding to the thickness of medium  10 . Accordingly, measuring shaft  17  may be rotated corresponding to the thickness of the medium  10  by first rotary arm  19 . Accordingly, second rotary arm  21  fixedly installed at measuring shaft  17  may be rotated. Body  31 , being in contact with hooking jaw  34 , near the end portion of second rotary arm  21 , may be rotated around a pivot of rotational shaft  32  according to the rotation of second rotary arm  21 . Rotational displacement of body  32  may be detected by rotational displacement detecting unit  35  and a thickness of medium  10  may be calculated from the rotational displacement of rotational displacement detecting unit  35 .  
         [0016]    Rotational displacement detecting unit  35  may use a differential transformer (i.e. a rotary variable differential transformer) to accurately detect a rotational displacement corresponding to the thickness of medium  10  having a small thickness dimension. However, embodiments utilizing a differential transformer have some disadvantages. For instance, differential transformers are relatively expensive. Further, differential transformers should be fabricated and assembled very precisely. Therefore, their fabrication and assembling is expensive.  
         [0017]    A thickness measuring apparatus of embodiments of the present invention may include a conveyance unit having a conveyance roller  110  and/or an idle roller  130  for conveying medium  100 . Displacement transformation unit may be for transforming a displacement (δ) of idle roller  130  to a rotational displacement (θ) according to the thickness (δ) of medium  100  when medium  100  passes between conveyance roller  110  and idle roller  130 . A rotational displacement detecting unit may be for detecting a rotational displacement by changing a quantity of light depending on the rotational displacement (θ). Thickness calculating unit  440  may be for calculating a thickness of medium  100  from rotational displacement detected by rotational displacement detecting unit. Medium  100  may be a bill, photocopy paper, and/or print paper used for either an ATM, a photocopier, or a printer.  
         [0018]    Idle roller  130 , which may be included in a conveyance unit, may be installed at rotational shaft  131 , which may not be rotated but may rotatably support idle roller  130 . Rotational shaft  131  may be installed to be accessible to or separated from the conveyance roller  110 . Displacement transformation unit may transform linear displacement of rotational shaft  131  of idle roller  130  to rotational displacement of medium  100  passing conveyance roller  110  and idle roller  130 . Displacement transformation unit may include a rotary arm  120  of which one end may be fixed at rotational shaft  131  of idle roller  130  and/or the other end may be fixed at transformation rotational shaft  170  so that rotary arm  120  may be rotated centering around transformation rotational shaft  170  by displacement (δ) of rotational shaft  131  of idle roller  130 . For example, a small displacement (δ) of idle roller  130  may be transformed to a rotational displacement (θ) of transformation rotational shaft  17  by rotary arm  120 .  
         [0019]    Rotational displacement detecting unit may include an input unit  220 , a detection rotational shaft  270 ; a rotational member  210 , and/or a rotational displacement detecting unit. Input unit  220  may be for receiving rotational displacement (θ). Detection rotational shaft  270  may be rotated as much as corresponding to rotational displacement (θ) inputted to input unit  220 . Rotational member  210  may be fixedly installed at detection rotational shaft  270  and may be rotated according to rotation of detection rotational shaft  270 . Rotational displacement detecting unit may be installed at a free end of rotational member  210  and may detect a rotational displacement by changing a quantity of light received according to rotational displacement (θ).  
         [0020]    Input unit  220  may include rotary arm  120  of displacement transformation unit and may receive a small displacement of idle roller  130 . Rotary arm  120  may transmit displacement as a rotational displacement of transformation rotational shaft  170 . Detection rotational shaft  270  may be coaxially formed with transformation rotational shaft  170  of displacement transformation unit, to receive rotational displacement (θ) from rotary arm  120 . Since rotational displacement may be very small (i.e. due to the thickness of paper), the rotational displacement may need to be amplified. Rotational member  210  may be longer than rotary arm  170 . Displacement of rotational displacement detecting unit which may be installed at a free end of rotational member  210  and may be increased for input of rotational displacement (θ). In embodiments, in order to amplify a small rotational displacement, an additional rotational displacement amplifying unit (not shown) of a link structure consisting of rotary arms with different lengths may be connected between detection rotational shaft  270  and transformation rotational shaft  170 .  
         [0021]    In embodiments, rotational displacement detecting unit may include a first light transmission member  310 , a second light transmission member  320 , a light receiving unit  420 , and a rotational displacement calculating unit  430 . First light transmission member  310  may be fixedly installed at a free end of rotational member  210  and may be moved according to rotation of rotational member  210 . Second light transmission member  320  may be fixed to be overlapped with first light transmission member  310  when the first light transmission member  310  is moved. A light emitting unit  210  may be for irradiating light to first light transmission member  310  and second light transmission member  320 . Light receiving unit  420  may be for detecting a quantity of light irradiated by light emitting unit  410  which may change as overlap between first light transmission member  310  and second light transmission member  320  changes. Rotational displacement calculating unit  430  may be for calculating a rotational displacement from the quantity of light detected by light receiving unit  420 .  
         [0022]    Light emitting unit  410  may be fixedly installed near first and second light transmission members  310  and  320  in order to irradiate light to be transmitted through first and second light transmission members  310  and  320  to light receiving unit  420 . Light receiving unit  420  may be fixedly installed near first and second light transmission members  310  and  320  so as to detect light having passed first and second light transmission members  310  and  320 . Rotational displacement calculating unit  430  may be connected to light receiving unit  420  and may calculate a rotational displacement (θ) of rotary arm  180  upon receiving a signal according to a change in the quantity of light of light receiving unit  420 .  
         [0023]    [0023]FIGS. 3, 4 and  5  are exemplary illustrations of second light transmission member  320  which may be fixed close to first light transmission member  310 . First light transmission member  310  may be fixedly installed at a free end of rotational member  210 . First light transmission member  310  and second light transmission member  320  may use a polarization filter or a slit in the direction in which light is irradiated to change the quantity of light received at light receiving unit  420 . Particularly, the quantity of light may be changed as first and second light transmission members  310  and  320  are mutually interfered owing to a displacement of the first light transmission member  310  according to rotation of rotational member  210 .  
         [0024]    In exemplary embodiments where first and second light transmission members  310  and  320  are used as polarizing filters (i.e. embodiments illustrated in FIG. 3), rotational member  210  is rotated according to rotation of transformation rotational shaft  170 . First rotational member  310  may be installed at a free end of rotational member  210 . Rotational member  210  may be moved and overlapped with second rotational member  320  as much as corresponding to a rotational displacement (θ), thereby changing the quantity of light received by light receiving unit  420 .  
         [0025]    In embodiments, by installing a polarizing filter used for first light transmission member  310  and second light transmission member  320  such that the polarization direction can be vertical, light may be interrupted as much as the first light transmission member  310  and the second light transmission member  320  are overlapped. Light interruption may be detected by light receiving unit  420 . Rotational displacement calculating unit  430  may calculate rotational displacement (θ) of rotary arm  120  from the quantity of light received at the light receiving unit  420 .  
         [0026]    In embodiments, first and second slits  511  and  521  may be sequentially disposed in a direction of light irradiation of the light emitting unit  410 . As illustrated in exemplary FIGS. 4 and 5, first light transmission member  510  may be moved as much as the rotational displacement (θ) of rotational member  210 . First and second slits  511  and  521  may be formed at first and second light transmission members  510  and  520  and may be diverged from each other. Consequently the quantity of light detected by light receiving unit  420  may change. Rotational displacement calculating unit  430  may calculate rotational displacement (θ) of rotary arm  120  according to the quantity of light detected by light receiving unit  420 .  
         [0027]    A rotational displacement detecting apparatus may be applicable in many diverse fields as an apparatus for measuring infinitesimal rotational displacement. A thickness calculating unit may calculate a thickness of a medium passing a conveyance roller and an idle roller. Rotational displacement may be calculated by a rotational displacement calculating unit of rotational displacement detecting apparatus. Rotational displacement and thickness of a medium may be calculated on a basis of relations (1=rθ) between a length (1) of an arc, a radius (r) of the arc, and an angle (θ) of the arc. Mathematical equations may be used (i.e. relations among lengths of each side of a triangle, an interior angle, and an exterior angle of the triangle).  
         [0028]    Embodiments of the present invention have many advantages. For example, unlike a RVDT which is relatively costly and needs relatively high precision, a comparatively low-priced light emitting device, light receiving device, first light transmission member, and/or second light transmission member may be used. Accordingly, embodiments of the present invention are advantageous, because manufacturing costs may be reduced. Further, since parts do not need to have the same high precision as a RVDT, fabrication is simplified. Since a rotational displacement detecting apparatus is used for a thickness measuring apparatus for measuring a thickness of a medium conveyed by a conveyance unit, thickness of a medium can be detected by a relatively simple apparatus.  
         [0029]    Objects of embodiments of the present invention are to provide a rotational displacement detecting apparatus that is capable of detecting a rotational displacement with a simple structure and to provide a thickness measuring apparatus that is capable of measuring a thickness of a medium by using the rotational displacement apparatus with the simple structure.  
         [0030]    To achieve these and other advantages and in accordance with the purpose of embodiments of the present invention, as embodied and broadly described herein, there may be provided a thickness detecting apparatus including: a conveyance unit having a conveyance roller and an idle roller for conveying a medium; a displacement transforming unit for transforming a displacement of the idle roller to a rotational displacement depending on the thickness of the medium when the medium passes between the conveyance roller and the idle roller; a rotational displacement detecting unit having a detector for detecting a rotational displacement by changing a quantity of light according to the rotational displacement; and/or a thickness calculating unit for calculating the thickness of the medium from the rotational displacement detected by the rotational displacement detecting unit.  
         [0031]    To achieve the above objects, there may also provided a thickness measuring apparatus including: a conveyance unit having a conveyance roller and an idle roller for conveying a medium; a rotary arm of which one end is fixedly installed at a rotational shaft of the idle roller and the other end is fixedly installed at a transformation rotational shaft installed parallel to a rotational shaft of the idle roller, so as to rotate the transformation rotational shaft according to displacement of the rotational shaft of the idle roller caused when the medium passes the conveyance roller and the idle roller; a rotational member fixedly installed at the transformation rotational shaft so as to be rotated together with the transformation rotational shaft; a first light transmission member fixedly installed at a free end of the rotational member and moved according to rotation of the rotational member; a second light transmission member fixed to be overlapped at some portion with the first light transmission member when the first light transmission member is moved; a light emitting unit for irradiating light to the first light transmission member and the second fight transmission member; a light receiving unit for detecting a quantity of light irradiated by the light emitting unit which is changed as the first light transmission member and the second light transmission member are overlapped; a rotational displacement calculating unit for calculating a rotational displacement from the quantity of light detected by the light receiving unit; and/or a thickness calculating unit for calculating a thickness of the medium from the rotational displacement calculated by the rotational displacement calculating unit.  
         [0032]    In order to achieve at least some objects, there may be provided a rotational displacement detecting apparatus including: an input unit for receiving a rotational displacement; a rotational shaft fixedly installed at the rotational shaft and rotated according to the rotational displacement of the rotational shaft; and/or a rotational displacement detecting unit installed at a free end of the rotational member and detecting a rotational displacement by changing quantity of light according to the rotational displacement.  
         [0033]    The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures.