Patent Publication Number: US-2004041330-A1

Title: Media pick-up device of media dispenser

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a media dispenser, and more particularly, to a media pick-up device of a media dispenser which can use various kinds of media of different thickness.  
       [0003] 2. Description of the Related Art  
       [0004]FIG. 1 is a construction view showing a media dispenser in accordance with the conventional art.  
       [0005] As shown in FIG. 1, the media dispenser according to the conventional art comprises: a base plate  6  in which a media cassette  2  for storing media and a reject box  4  for collecting inferior media are loaded; a media pickup unit  8  installed at the lower side of the base plate  6  for discharging the media stored in the media cassette  2  by separating sheet by sheet; a media feeding unit  10  for feeding the media discharged through the media pickup unit  8 ; a media discharging unit  12  for discharging the media fed by the media feeding unit  10  to outside; a driving means for generating driving force; a power transmitting means for transmitting the driving force generated at the driving means to each unit; and a media rejection means for separating and collecting abnormal media.  
       [0006] The base plate  6  has an interior loading space for loading the media cassette  2  at the front side, another interior loading space for loading the reject box  4  for loading inferior media at the upper side of the above interior loading space, and a door  16  at the front side of the two interior loading spaces.  
       [0007] A locking system  18  for preventing an arbitrary external access to the media cassette  2  and the reject box  4  is installed at the door  16 . Also, a cushion member  20  abutted on the front surface of the media cassette  2  for buffering impact is installed on the inner surface of the door  16 .  
       [0008] A power board  22  for using the power supplied from outside in overall components of the media dispenser directly is installed at the lower side of the position where the media cassette  2  of the base plate  6  is loaded.  
       [0009] It is desirable that the driving means is a driving motor  24  installed at one side of the base plate  6  for generating rotational force. A driving pulley  26  is installed in the driving motor  24 .  
       [0010] The above power transmitting means transmits power generated in the driving motor  24  to each unit. A driving pulley  26  of the driving motor is connected to a driven pulley  30  by a driving belt  28  and power is transmitted to the driven pulley  30 . A timing belt  32  is wound on the driven pulley  30 , a lower connection pulley  34  for driving the media pickup unit  8  is wound at the lower end of the timing belt  32  and an eject pulley  36  for driving the media discharging unit  12  is wound at the upper end of the timing belt  32 .  
       [0011] A plurality of tension pulleys  38  and  40  for maintaining tension of the timing belt  32  are installed at one side of the timing belt  32 .  
       [0012] The lower connection pulley  34  transmits rotational force generated by the rotation of the timing belt  32  to the media pickup unit  8  and transmits the rotational force to the media feeding unit by being connected to the media feeding unit.  
       [0013] The media feeding unit  10  for guiding the media discharged through the media pickup unit  8  to the media discharging unit  12 , comprises a first feeding belt  74  wound between a first feeding roller  70  which is positioned on the identical shaft as the lower connection pulley  34  and a second feeding roller  72  positioned at the upper side; and a second feeding belt  76  positioned under the condition of being abutted to the first feeding belt  74 , which is rotated to feed the media.  
       [0014] The first feeding belt  74  is wound between the first feeding roller  70  which is positioned on the identical shaft as the above lower connection pulley  34  and the second feeding roller  72 , rotating by receiving rotational force from the above lower connection pulley  34  and a plurality of guide rollers  78  and  80  for guiding the media are installed at one side of the first feeding belt  74  rotatably.  
       [0015] The second feeding belt  76  positioned under the condition of being abutted to the outer surface of the first feeding belt  74  rotates in the same direction of the first feeding belt  74  and is wound between a third feeding roller  82  which is positioned at the lower side of the base plate  6  rotatably and a fourth feeding roller  84  positioned at the upper front end of the base plate  6 .  
       [0016] A plurality of guide rollers  86  and  88  for guiding the second feeding belt  76  are positioned at one side of the second feeding belt  76 .  
       [0017] Here, the fourth feeding roller  84  is positioned on the identical shaft as a gear  90  in gear with the eject pulley  36  on which the timing belt  32  is wound and receives the rotational force thus to drive the above second feeding belt  76 .  
       [0018] In the above media feeding unit  10 , when the driving motor  24  is driven, the timing belt  32  rotates and accordingly, the lower connection pulley  34  and the eject pulley  36  rotate. Then, the first feeding roller  70  positioned on the identical shaft as the lower connection pulley  34  rotates and has the first feeding belt  74  rotate. The fourth feeding roller  84  in gear with the eject pulley  36  rotates and has the second feeding belt  76  rotate.  
       [0019] Then, the media discharged through the above media pickup unit  8  pass through between the first feeding belt  74  and the second feeding belt  76  and are guided to the media discharging unit  12 .  
       [0020] The media discharging unit  12  discharges the media fed from the media feeding unit  10  to the user and the media discharging unit  12  comprises a first discharging roller  98  which is positioned on the identical shaft as the eject pulley  36  and rotates; and a second discharging roller  100  connected to the first discharging roller  98  by a discharging belt  102 . The discharging belt  102  under the condition of being abutted to the upper side of the second feeding belt  76  is rotated in the same direction and discharges the media to outside.  
       [0021] As shown in FIGS. 2 and 3, the media pickup unit  8  for discharging the media cassette by separating sheet by sheet, comprises: a pickup roller  42  positioned at the rear side of the media cassette  2  for discharging the media stored in the media cassette  2  to the lower direction by friction; a feeding roller  44  and a separating roller  46  positioned at the lower side of the pickup roller  42 , for feeding the media discharged by the pickup roller  42  by separating the media sheet by sheet; and a guide member  48  for guiding the media fed through the feeding roller  44  and separating roller  46  to the upper direction.  
       [0022] The pickup roller  42  is positioned at the rear side of the media cassette  2  rotatably and a rubber unit  50  is formed on a certain part of the circumferential surface. Accordingly, the rubber unit  50  rubs with the media, discharges the media by separating and receives power in gear with the feeding roller  44 .  
       [0023] Namely, a driving gear  60  and a driven gear  58  are installed on the rotation shafts  54  and  56  of the feeding roller and the pickup roller, and an idle gear  52  is in gear between the driving gear  60  and driven gear  58  thus to transmit the rotational force of the feeding roller  44  to the pickup roller  42 .  
       [0024] Pulleys  110  and  112  are respectively fixed to the rotation shaft  56  of the feeding roller  44  and the rotation shaft  114  of the separating roller  46 , and a connection belt  62  is wound between the pulleys  110  and  112  thus to be rotated in the same direction. Also, the feeding roller  44  and the separating roller  46  maintain a predetermined overlap thus to feed the media discharged through the pickup roller  42  by separating sheet by sheet. That is, several sheets of media are inputted as the feeding roller  44  rotates, and the several sheets of media inputted by the rotation of the feeding roller  44  are separated one sheet by one sheet by friction in accordance with that the separating roller  46  rotates in the same direction of the feeding roller  44 .  
       [0025] Herein, in case that the overlap amount between the feeding roller  44  and the separating roller  46  is fixed as about 0.4 mm, media having thickness only of 0.1˜0.3 mm can be used.  
       [0026] A clutch  64  for controlling power transmitted from the lower connection pulley  34  to the feeding roller  44  is installed at the rotation shaft  54  of the feeding roller  44 . That is, the clutch  64  is installed on the same shaft as the feeding roller  44  and connected in gear with the lower connection pulley  34  by a clutch gear  66 , thereby transmitting or intercepting the power transmitted from the lower connection pulley  34  to the feeding roller  44 .  
       [0027] Herein, the clutch  64  uses a solenoid method to transmit power in case power supply is applied and intercept power in case power supply is intercept. Contrarily, another solenoid method to intercept power in case power supply is applied and transmit power in case power supply is intercept can be used.  
       [0028] Such media pickup unit  8  transmits the rotational force of the lower connection pulley  34  to the feeding roller  44  when the clutch means  64  is on. Then the separating roller  46  wound on the feeding roller  44  by the connection belt  62  rotates, and the pickup roller  42  in gear with the feeding roller  44  rotates together. Then, as the pickup roller  42  rotates, the rubber unit  50  of the pickup roller  42  discharges the media downwardly by being rubbed with the media. The media discharged by the pickup roller  42  are separated passing through between the feeding roller  44  and the separating roller  46  and the separated media move upwardly along the guide member  48  and are guided to the media feeding unit  10 .  
       [0029] When the clutch means  64  is turned off, power transmitted from the lower connection pulley  34  to the feeding roller  44  is intercept, thus to stop the media pickup operation.  
       [0030] According to on/off of the clutch means  64 , the media pickup unit  8  performs pickup/pickup halting operation repeatedly.  
       [0031] However, in the media pickup device of the media dispenser, since the feeding roller  44  and the separating roller  46  are connected by the connection belt  62  and the overlap amount therebetween is fixed, only media having thickness proper to the overlap amount can be used. According to this, various kinds of media having various thickness can not be used.  
       SUMMARY OF THE INVENTION  
       [0032] Therefore, an object of the present invention is to provide a media pickup device of a media dispenser which can use various kinds of media having different thickness by installing a variable means at a separating roller and thus by varying an overlap amount between a feeding roller and the separating roller.  
       [0033] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a media pickup device of a media dispenser comprising: a feeding roller and a separating roller arranged with a predetermined interval for separating media discharged from a media cassette sheet by sheet and feeding; and a variable means for varying an overlap amount between the feeding roller and the separating roller according to thickness of media.  
       [0034] At a rotation shaft of the separating roller of the media pickup device, installed is a one-way clutch which makes the separating roller maintain a static state in a direction where media pass and rotate in the opposite direction thereof  
       [0035] The variable means comprises: a supporting bracket for supporting both ends of the rotation shaft of the separating roller; a supporting shaft for rotatably supporting another side of the supporting bracket; and a torsion spring installed between the supporting shaft and the supporting bracket for providing a predetermined elastic force to push the separating roller to the feeding roller.  
       [0036] One side of the supporting bracket of the media pickup device is fixed to both ends of the rotation shaft of the separating roller, another side thereof is rotatably supported by being inserted to the supporting shaft, and a stopper for determining an initial overlap amount between the feeding roller and the separating roller is formed at one side thereof.  
       [0037] The torsion spring of the media pickup device is wound on the supporting shaft, and is formed as a coil spring of which one end is fixed on the supporting shaft and another end is fixed to the supporting bracket.  
       [0038] The media pickup device of the media dispenser according to the present invention comprises: a feeding roller and a separating roller arranged with a predetermined interval for separating media discharged from a media cassette sheet by sheet and feeding; a variable means for varying an overlap amount between the feeding roller and the separating roller according to thickness of media; and an adjusting unit for adjusting a maximum overlap amount between the feeding roller and the separating roller.  
       [0039] The variable means for varying the overlap amount comprises: a supporting bracket for supporting both ends of the rotation shaft of the separating roller; a supporting shaft for fixing another side of the supporting bracket and being rotatably supported by a base plate; and a tension spring connected to one side of the supporting shaft for pushing the separating roller to the feeding roller.  
       [0040] The tension spring is a coil spring connected between a connection bracket fixed to one side of the supporting shaft and a connection rod fixed to the base plate.  
       [0041] A stopper for determining an initial overlap amount between the feeding roller and the separating roller is contacted on the front surface of the connection frame, and an adjusting unit for adjusting a maximum overlap amount between the feeding roller and the separating roller is installed at the rear surface of the connection frame.  
       [0042] The adjusting unit of the media pickup device comprises: an adjusting bracket fixed to the base plate; and an adjusting bolt screw-engaged to the adjusting bracket and thus contacted to the rear surface of the connection frame for adjusting a maximum rotation amount of the supporting shaft.  
       [0043] The media pickup device of the media dispenser according to the present invention comprises: a feeding roller and a separating roller arranged with a predetermined interval for separating media discharged from a media cassette sheet by sheet and feeding; a tension spring for pushing the separating roller to the feeding roller in order to vary an overlap amount therebetween according to thickness of media; and a tension adjusting means for adjusting tension of the tension spring.  
       [0044] The tension adjusting means of the media pickup device is an adjusting bolt for adjusting tension of the spring by being inserted to a through hole formed at the connection frame and screw-engaged to a base plate.  
       [0045] The media dispenser according to the present invention comprises: a media pickup unit for discharging media stored in a media cassette by separating sheet by sheet; a media feeding unit for feeding the media discharged through the media pickup unit; and a media discharging unit for discharging the media fed through the media feeding unit to outside, in which the media pickup unit comprises: a feeding roller and a separating roller for separating media discharged from the media cassette sheet by sheet and feeding; and a variable means for varying an overlap amount between the feeding roller and the separating roller according to thickness of media by being connected to the separating roller.  
       [0046] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0047] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.  
     [0048] In the drawings:  
     [0049]FIG. 1 is a construction view showing a media dispenser in accordance with the conventional art;  
     [0050]FIG. 2 is a perspective view showing a media pickup device in accordance with the conventional art;  
     [0051]FIG. 3 is a lateral view showing the media pickup device in accordance with the conventional art;  
     [0052]FIG. 4 is a lateral view showing a media pickup device according to the present invention;  
     [0053]FIG. 5 is a front view showing the media pickup device according to the present invention;  
     [0054]FIGS. 6 and 7 are views showing operational state of the media pickup device according to the present invention;  
     [0055]FIG. 8 is a lateral view showing the media pickup device according to a second embodiment of the present invention;  
     [0056]FIG. 9 is a frontal view of the media pickup device according to the second embodiment of the present invention;  
     [0057]FIG. 10 is a lateral view showing the media pickup device according to a third embodiment of the present invention; and  
     [0058]FIG. 11 is a front view of the media pickup device according to the third embodiment of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0059] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
     [0060]FIG. 4 is a lateral view showing a media pickup device according to the present invention, and FIG. 5 is a front view showing the media pickup device according to the present invention.  
     [0061] Referring to FIG. 1, the media dispenser according to the present invention a base plate  6  in which a media cassette  2  for storing media and a reject box  4  for collecting inferior media are loaded; a media pickup unit  8  installed at the lower side of the base plate  6  for discharging the media stored in the media cassette  2  by separating sheet by sheet; a media feeding unit  10  for feeding the media discharged through the media pickup unit  8 ; a media discharging unit  12  for discharging the media fed by the media feeding unit  10  to outside; a driving means for generating driving force; a power transmitting means for transmitting the driving force generated at the driving means to each unit; and a media rejection means for separating and collecting abnormal media.  
     [0062] The media dispenser according to the present invention has the same construction and operation as that of the conventional art except the media pickup unit, thereby omitting its explanation.  
     [0063] As shown in FIGS. 4 and 5, the media pickup device according to one embodiment of the present invention comprises: a pickup roller  150  positioned at the rear side of the media cassette  2  for discharging the media stored in the media cassette  2  to the lower direction by friction; a feeding roller  154  and a separating roller  156  positioned at the lower side of the pickup roller  150 , for feeding the media discharged by the pickup roller  150  by separating the media sheet by sheet; and a variable means installed at the separating roller  156  for varying an overlap amount between the feeding roller  154  and the separating roller  156 .  
     [0064] The pickup roller  150  is positioned at the rear side of the media cassette  2  rotatably, and a rubber unit  152  is formed on a certain part of the circumferential surface. Accordingly, the rubber unit  152  rubs with the media, discharges the media stored in the media cassette  2  by separating.  
     [0065] The feeding roller  154  is positioned at the lower side of the pickup roller  150  rotatably, and a rotation shaft  158  of the feeding roller  154  is connected with the power transmitting means thus to rotate the feeding roller  154 .  
     [0066] Also, a clutch  160  for controlling power transmitted from the power transmittance means to the feeding roller  154  is installed at the rotation shaft  158  of the feeding roller  154 .  
     [0067] Herein, the clutch  160  uses a solenoid method to transmit power in case power supply is applied and intercept power in case power supply is intercept. Contrarily, another solenoid method to intercept power in case power supply is applied and transmit power in case power supply is intercept can be used.  
     [0068] The separating roller  156  is positioned to have a predetermined overlap amount with the feeding roller  154  and maintains a static state, so that media which passes through between the separating roller  156  and the feeding roller  154  can be separated sheet by sheet by friction.  
     [0069] That is, one way clutch  164  is respectively formed at both ends of a rotation shaft  162  of the separating roller  156 . The one way clutch  164  makes the separating roller  156  maintain a static state in a direction where media pass thus to generate friction with the media, and makes the separating roller  156  rotate in the opposite direction thereof thus to prevent partial side wear from being generated at a friction surface of the separating roller  156 .  
     [0070] The variable means comprises: a supporting bracket  166  for supporting both ends of the rotation shaft  162  of the separating roller  156 ; a supporting shaft  168  for rotatably supporting another side of the supporting bracket  166 ; and a torsion spring  170  installed between the supporting shaft  168  and the supporting bracket  166  for providing a predetermined elastic force to push the separating roller  156  to the feeding roller  154 .  
     [0071] One side of the supporting bracket  166  of the media pickup device is wound and fixed to an outer circumference surface of the one way clutch  164  arranged both ends of the rotation shaft  162  of the separating roller  156 , and another side thereof is rotatably supported by being inserted to the supporting shaft  168 . Also, a stopper  172  is formed at one side thereof to prevent the supporting bracket  166  from being rotated more than a predetermined number of times by an elastic force of the torsion spring  170 .  
     [0072] That is, the stopper  172  is prolonged from one side of the supporting bracket  166  and blocked by a blocking pin  174  fixed to the base plate  6 . According to this, an initial overlap amount between the feeding roller  154  and the separating roller  156  is set.  
     [0073] At this time, the initial overlap amount between the feeding roller  154  and the separating roller  156  is set on the basis of a case that thickness of the media is minimum.  
     [0074] The supporting shat  168  rotatably supports the supporting bracket  166  under a state that both ends thereof are fixed to the base plate  6 , respectively.  
     [0075] The torsion spring  170  formed of a coil spring is wound on the supporting shaft  168 , and has one end fixed on the supporting shaft  168  and another end fixed to the supporting bracket  166 . That is, the torsion spring  170  provides the elastic force to the supporting bracket  166  with one direction, thereby pushing the feeding roller to the separating roller.  
     [0076] The torsion spring  170  has a predetermined elastic force so as to vary the overlap amount between the separating roller and the feeding roller according to thickness of the media which pass through therebetween.  
     [0077] Operations of the media pickup device of the media dispenser according to one embodiment of the present invention will be explained.  
     [0078]FIGS. 6 and 7 are views showing operational state of the media pickup device according to the present invention.  
     [0079] If the driving means is operated, power is transmitted to the rotation shaft  158  of the feeding roller  154  through the clutch  160 , thus the feeding roller is operated and the pickup roller  150  in gear with the feeding roller  154  is rotated.  
     [0080] When the pickup roller  150  is rotated, a media  180  stored in the media cassette  2  is rubbed with the rubber unit  152  of the pickup roller  150 , discharges towards the lower direction, separated sheet by sheet by passing through between the feeding roller  154  and the separating roller  156 , and guided by the media feeding unit  10 , thereby being discharged to outside through the discharging unit  12 .  
     [0081] At this time, the rotation shaft  162  of the separating roller  156  is supported by the one way clutch  164  and maintains a static state towards a direction where the media  180  is discharged thus to generate friction with the media  180  and to separate the media  180  sheet by sheet. Also, the rotation shaft  162  is rotated in the opposite direction thus to prevent partial side wear from being generated.  
     [0082] As shown in FIG. 6, when a thick media  182  passes through between the feeding roller  154  and the separating roller  156 , the separating roller  156  overcomes an elastic force of the torsion spring  170  by a pushing force of the media  182  and then moves towards the lower side direction. According to this, an overlap amount between the feeding roller  154  and the separating roller  156  becomes less and thereby the thick media  182  can be easily separated.  
     [0083] Also, when a thicker media  184  is introduced, as shown in FIG. 7, the separating roller  156  more moves towards the lower side direction and thereby the overlap amount between the feeding roller  154  and the separating roller  156  becomes much less. At this time, the overlap amount is maintained by the elastic force of the torsion spring  170 .  
     [0084]FIG. 8 is a lateral view showing the media pickup device according to a second embodiment of the present invention, and FIG. 9 is a frontal view of the media pickup device according to the second embodiment of the present invention.  
     [0085] The media pickup device according to the second embodiment of the present invention comprises: a feeding roller  154  and a separating roller  156  positioned at the lower side of the pickup roller  150  for separating the media discharged from the pickup roller  150  sheet by sheet and feeding; and a variable means installed at the separating roller  156  for varying an overlap amount between the feeding roller  154  and the separating roller  156  according to thickness of media.  
     [0086] The variable means comprises: a supporting bracket  190  for supporting both ends of the rotation shaft  162  of the separating roller  156 ; a supporting shaft  192  for fixing another side of the supporting bracket  190  and being rotatably supported by the base plate  6 ; and a tension spring  194  connected to one side of the supporting shaft  192  for providing a predetermined elastic force so that the supporting shaft  192  can be rotated in one direction.  
     [0087] The supporting bracket  190  has one end portion fixed on the supporting shaft  192  with a predetermined interval and the other end portion for supporting both ends of the rotation shaft  162  of the separating roller  156 . A one way clutch  196  is installed at the rotation shaft  162  thus to rotate the separating roller  156  only in one direction.  
     [0088] A connection bracket  198  is fixed to one side of the supporting shaft  192  with a predetermined angle, and the tension spring  194  is connected between the connection bracket  198  and a connection rod  200  fixed to the base plate  6 .  
     [0089] Also, a stopper  202  for setting an initial overlap amount between the feeding roller  154  and the separating roller  156  is contacted on the front surface of the connection bracket  198 , and an adjusting unit for adjusting a maximum overlap amount between the feeding roller  154  and the separating roller  156  by controlling rotation amount of the supporting shaft  192  is positioned at the rear surface of the connection bracket  198 .  
     [0090] The stopper  202  is fixed to the base plate  6  and contacted on the front surface of the connection bracket  198  and thereby prevents the supporting shaft  192  from being rotated more than a predetermined number of times by the elastic force of the tension spring  194 . It is preferable that the initial overlap amount is set when thickness of the media is minimum.  
     [0091] The adjusting unit of the media pickup device comprises: an adjusting bracket  204  fixed to the base plate  6 ; and an adjusting bolt  206  screw-engaged to the adjusting bracket  204 . The adjusting unit controls a distance between the connection bracket  198  and the adjusting bolt  206  by tightening or loosening the bolt  206 , thereby controlling maximum rotation amount of the supporting shaft  192 .  
     [0092] That is, if the adjusting bolt  206  is controlled, the maximum rotation amount of the supporting shaft  192  is set and thereby a maximum overlap amount between the feeding roller  154  and the separating roller  156  is determined.  
     [0093] Operations of the media pickup device according to the second embodiment of the present invention will be explained.  
     [0094] First, the distance between the adjusting bolt  206  and the connection bracket  198  is controlled by tightening or loosening the adjusting bolt  206 , thereby determining maximum thickness of a media to be used.  
     [0095] Then, if the pickup roller  150  is rotated, the media  180  stored in the media cassette  2  is rubbed with the rubbing unit  152  of the pickup roller  150 , discharged to the lower side direction, passes through between the feeding roller  154  and the separating roller  156 , and thereby separated sheet by sheet.  
     [0096] At this time, in case that a thick media is used, the media is introduced between the feeding roller  154  and the separating roller  156  by the rotation of the feeding roller  154  and the separating roller  156  is separated from the feeding roller  154  by the introduction force of the media. According to this, the overlap amount between the separating roller  156  and the feeding roller  154  is controlled.  
     [0097] That is, the separating roller  156  maintains a predetermined overlap amount with the feeding roller  154  by having a predetermined elastic force by the torsion spring  194 . Under this state, if a thick media is introduced, the separating roller  156  overcomes the elastic force of the torsion spring  194  and moves toward the lower side direction, thereby controlling the overlap amount with the feeding roller  154 .  
     [0098]FIG. 10 is a lateral view showing the media pickup device according to a third embodiment of the present invention, and FIG. 11 is a front view of the media pickup device according to the third embodiment of the present invention.  
     [0099] The media pickup device according to the third embodiment of the present invention comprises: a feeding roller  154  and a separating roller  156  positioned at the lower side of the pickup roller  150  for separating the media discharged from the pickup roller  150  sheet by sheet and feeding; and a variable means installed at the separating roller  156  for varying an overlap amount between the feeding roller  154  and the separating roller  156  according to thickness of media.  
     [0100] The variable means comprises: a supporting bracket  220  for supporting both ends of the rotation shaft  162  of the separating roller  156 ; a supporting shaft  222  for fixing another side of the supporting bracket  220  and being rotatably supported by the base plate  6 ; a tension spring  224  connected to one side of the supporting shaft  222  for pushing the separating roller  156  to the feeding roller  154 ; and a tension adjusting means for adjusting tension of the tension spring  224 .  
     [0101] A connection bracket  226  is fixed to one side of the supporting shaft  222 , and a through hole  230  is formed at the connection bracket  226 . An adjusting bolt  228  for adjusting tension of the tension spring  224  is inserted to the through hole  230 , and screw-engaged to the base plate  6 .  
     [0102] Herein, the through hole  230  has a size to maintain a predetermined distance with the adjusting bolt  228  in order to move right and left on the basis of the supporting shaft  222 .  
     [0103] The tension spring  224  is installed between the connection bracket  226  and the adjusting bolt  228 , and thus provides a predetermined elastic force to the connection bracket  226 .  
     [0104] Like this, if the adjusting bolt  228  is tightened, the tension spring  224  is compressed and thus a tension of the spring becomes great, and vice versa.  
     [0105] A stopper  236  for adjusting an initial overlap amount between the feeding roller  154  and the separating roller  156  is positioned at the front surface of the connection bracket  226 , and an adjusting unit  238  for adjusting a maximum overlap amount between the feeding roller  154  and the separating roller  156  by controlling rotation amount of the supporting shaft  192  is installed at the rear surface of the connection bracket  226 .  
     [0106] Operations of the media pickup device according to the third embodiment will be explained.  
     [0107] Once the pickup roller  150  is rotated, the media stored in the media cassette  2  is rubbed with the pickup roller  150 , discharged towards the lower side direction, passes through between the feeding roller  154  and the separating roller  156 , and thereby separated sheet by sheet.  
     [0108] At this time, in case that a thick media is used, the media is introduced between the feeding roller  154  and the separating roller  156  by the rotation of the feeding roller  154 , and the separating roller  156  overcomes the elastic force of the tension spring  224  by the introduction force of the media and is separated from the feeding roller  154 . According to this, the overlap amount between the separating roller  156  and the feeding roller  154  is controlled.  
     [0109] At this time, if the adjusting bolt  228  is tightened or loosened, the tension spring  224  is compressed or relaxed and thereby intensity of force applied to the separating roller  156  is controlled.  
     [0110] That is, if the force applied to the separating roller  156  is great, the thick media has a difficulty in being discharged between the feeding roller  154  and the separating roller  156 . Contrary to this, if the force applied to the separating roller  156  is less, friction force between the separating roller  156  and the media becomes weak and thereby the media can not be separated sheet by sheet. Therefore, the force applied to the separating roller  156  has to be maintained at the optimum state.  
     [0111] Accordingly, tension of the tension spring  224  is adjusted by tightening or loosening the adjusting bolt  228 , and thereby the force applied to the separating roller  156  can be controlled as the optimum state.  
     [0112] The media pickup device of the media dispenser according to the present invention has the following effects.  
     [0113] The media pickup device can use various kinds of media having different thickness by installing the variable means which varies an overlap amount between the feeding roller  154  and the separating roller  156  at the separating roller  156 .  
     [0114] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.