Abstract:
A paper feeding device and an electronic apparatus having the same include a pickup roller moving upwardly and downwardly to selectively contact a document stacked on a document tray. A restrainer moves in directions for blocking a leading end of a document stacked on the document tray from the feeding roller when the pickup roller is lifted, and for unblocking the leading end of document from the feeding roller when the pickup roller is lowered. Accordingly, unintended contact between the document and the feeding roller is prevented when stacking the document, thereby preventing damage of the document during paper feeding.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application the claims benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 2005-50305, filed Jun. 13, 2005, the entire contents of which are hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an electronic apparatus. More particularly, the present invention relates to a paper feeding device supplying paper sheets into a main body of an electronic apparatus, and an electronic apparatus having the same.  
         [0004]     2. Description of the Related Art  
         [0005]     Generally, office electronic apparatuses, such as a photocopier, a scanner, a multifunction apparatus, and a printer, include a paper feeding device to supply a main body thereof with document sheets for recording thereon an image or document sheets bearing the image to be scanned. Recently, an automatic document feeder (ADF) has been developed and used, that is mounted on the outside of a main body of the electronic apparatus to automatically supply a plurality of document sheets one by one.  
         [0006]      FIG. 1  schematically shows a conventional paper feeding device used in an office electronic apparatus. Referring to  FIG. 1 , a paper feeding device  10  includes a pickup roller  30  picking up document M stacked on a document tray  15 . A feeding roller  20  feeds the document M picked up by the pickup roller  30  into the main body of the electronic apparatus. A friction member  40  is mounted corresponding to the feeding roller  20  to prevent the feeding of multiple sheets at one time into the main body.  
         [0007]     In the conventional paper feeding device  10 , when feeding the document M, the pickup roller  30  is lowered and brought into contact with the document M to feed the document M to the feeding roller  20 . The feeding roller  20  then transfers the document M fed by the pickup roller  30  into the main body of the electronic apparatus. When the paper feeding operation is completed, the pickup roller  30  is lifted back to an initial position. The conventional paper feeding device  10  as described above is convenient since it can feed many sheets of document M into the main body sheet by sheet.  
         [0008]     However, according to the conventional paper feeding device  10 , when the document M is put nearer the feeding roller  20  rather than a preset correct position P, a leading end of the document M may contact with the feeding roller  20  even before the paper feeding. When the feeding roller  20  is rotated in this state, multiple-sheet feeding may be caused. The multiple-sheet feeding refers to an occurrence where a plurality of document sheets are overlappedly fed at once. Additionally, when many sheets of document M are stacked incorrectly as described above, the document M stacked at an upper part may be bent and damaged by contact with the feeding roller  20 , as shown in  FIG. 1 . Furthermore, paper jams may be generated so that the document M cannot be advanced into the main body of the electronic apparatus. Thus, when the conventional paper feeding device  10  cannot assure normal operation of paper feeding, printing and scanning of an image may not be correctly performed.  
         [0009]     Accordingly, a need exists for an improved paper feeding device for an electronic apparatus that substantially prevents feeding multiple sheets at one time.  
       SUMMARY OF THE INVENTION  
       [0010]     Accordingly, an aspect of the present invention is to provide an improved paper feeding device capable of assuring normal operation of paper feeding, and an electronic apparatus having the same.  
         [0011]     A paper feeding device and an electronic apparatus having the same include a restrainer moving in directions for blocking a leading end of a document stacked on the document tray from the feeding roller when the pickup roller is lifted, and for opening a pathway between the leading end of the document from the feeding roller when the pickup roller is lowered.  
         [0012]     According to another aspect of the present invention, paper feeding device and an electronic apparatus having the same include a paper feeding device for an electronic apparatus. A feeding roller is rotatable in a first direction for feeding a document picked up and fed from a document tray by a pickup roller into a main body of the electronic apparatus. A restrainer is movably disposed between the pickup roller and the feeding roller to open between the pickup roller and the feeding roller only when the feeding roller is rotated in the first direction.  
         [0013]     Therefore, unintended contact between the document and the feeding roller may be substantially prevented, thereby preventing damage of the document during paper feeding.  
         [0014]     According to an exemplary implementation of the present invention, the paper feeding device may further include a lifting and lowering driver that lowers the restrainer when the pickup roller is lifted and that lifts the restrainer when the pickup roller is lowered.  
         [0015]     According to an exemplary implementation of the present invention, the pickup roller is connected to a driving source provided to the electronic apparatus through a predetermined gear train. The lifting and lowering driver includes a pinion mounted at the gear train. A rack gear part is formed at one side of the restrainer along an ascending and descending direction of the restrainer and meshed with the pinion.  
         [0016]     According to an exemplary implementation of the present invention, the pinion is coaxially arranged with one selected from a plurality of idler gears mounted to the gear train. The lifting and lowering driver further includes a clutch for connection between the pinion and rotary shaft of the selected idler gear for selective power transmission.  
         [0017]     According to an exemplary implementation of the present invention, the pinion is connected with one of the idler gears, which is rotated in the same direction with the pickup roller.  
         [0018]     According to an exemplary implementation of the present invention, the pickup unit may include a feeding roller disposed between the driving source and the pickup roller to feed the document fed by the pickup roller into the main body of the electronic apparatus. The idler gear connected to the pinion is one of the plurality of idler gears connecting the feeding roller and the pickup roller to each other.  
         [0019]     According to an exemplary implementation of the present invention, the pickup unit may include a frame supporting the idler gears and the pickup roller to be rotatable, and pivoted with respect to the feeding roller when the feeding roller is rotated. The frame includes a guide groove to contactingly support sliding of the side of the restrainer.  
         [0020]     According to an exemplary implementation of the present invention, the clutch includes a spring clutch that rotates the pinion when the idler gears are rotated in a direction for lifting the restrainer and releases the connection between the idler gears and the pinion when the idler gears are rotated in a direction for lowering the restrainer, so that the restrainer descends by its own weight. According to this, power transmission by the idler gears and the pinion may be implemented with a simple structure and at a low cost.  
         [0021]     According to an exemplary implementation of the present invention, the restrainer includes a contacting portion for contact with the frame at a predetermined position when being lifted by rotation of the pinion.  
         [0022]     According to an exemplary implementation of the present invention, the paper feeding device may further include a detecting sensor detecting the document as fed to a predetermined position by the feeding roller. The feeding roller is driven in the opposite direction to a direction of feeding the document into the main body, thereby lifting the pickup roller and lowering the restrainer.  
         [0023]     According to an exemplary implementation of the present invention, the restrainer includes a stopper restraining the leading end of document from advancing to the feeding roller while the restrainer is lowered. A guide part is connected to one side of the stopper and faces an upper side of the document being fed to the feeding roller while the restrainer is lifted.  
         [0024]     According to an exemplary implementation of the present invention, the paper feeding device further includes a friction member mounted to face the feeding roller to substantially prevent multi-sheet feeding by friction with the document. The guide part is slanted with respect to the stopper to form an angle for guiding the document between the friction member and the feeding roller.  
         [0025]     Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the present invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
       [0026]     The above aspect and other features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawing figures, wherein;  
         [0027]      FIG. 1  is a view of a conventional paper feeding device;  
         [0028]      FIG. 2  is a schematic view of an image scanning apparatus employing the paper feeding device according to an exemplary embodiment of the present invention;  
         [0029]      FIG. 3  is a perspective view of a pickup unit of  FIG. 2 ; and  
         [0030]      FIGS. 4 and 5  are schematic views illustrating the operation of the pickup unit according to an exemplary embodiment of the present invention.  
     
    
       [0031]     Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures.  
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0032]     Hereinafter, certain exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawing figures.  
         [0033]     The matters defined in the description, such as a detailed construction and elements thereof, are provided to assist in a comprehensive understanding of the invention. Thus, it is apparent that the present invention may be carried out without those defined matters. Also, well-known functions or constructions are not described in detail to provide a clear and concise description of the exemplary embodiments.  
         [0034]      FIG. 2  shows an image scanning apparatus as an example of electric apparatuses including a paper feeding device according to an exemplary embodiment of the present invention.  
         [0035]     Referring to  FIG. 2 , an image scanning apparatus  100  according to an exemplary embodiment of the present invention includes a paper feeding device  200 , an image sensor S, and a paper feeding path  130  connecting the paper feeding device  200  and the image sensor S.  
         [0036]     The paper feeding device  200  includes a document tray  210  and a pickup unit  300  to supply a document M to the image sensor S. The document tray  210  is capable of stacking a plurality of sheets of document M thereon and exposed outside of the image scanning apparatus  100 . A detection sensor SI detects whether the document M is stacked on the document tray  210 .  
         [0037]     The pickup unit  300  feeds the document M stacked on the document tray  210  sheet by sheet to the image sensor S while driving a pickup roller  330 , and restrains the stacked document M from contacting with a feeding roller  320  during a standby mode. For this, as shown in  FIGS. 2 and 3 , the pickup unit  300  includes a feeding roller  320 , the pickup roller  330 , a restrainer  400 , and a lifting and lowering driver  360 .  
         [0038]     The pickup roller  330  feeds the document M stacked on the document tray  210  to the feeding roller  320 . The feeding roller  320  feeds the document M fed by the pickup roller  330  to the paper feeding path  130 . The feeding roller  320  may be rotated by a predetermined driving source provided in a main body  110  of the electronic apparatus. As shown in  FIG. 3 , the pickup roller  330  according to an exemplary embodiment of the present invention is transmitted with a rotational force from the feeding roller  320  through a gear train  350  including a plurality of idler gears  351 ,  352 , and  354  that are rotatably mounted on a frame  310 . The gear train  350  is provided to transmit the rotational force from the feeding roller  320  to the pickup roller  330 , which is at a predetermined distance from the feeding roller  320 . To rotate the pickup roller  330  and the feeding roller  320  in the same direction, the gear train  350  includes an odd number of idler gears. In this exemplary embodiment, therefore, the gear train  350  has first to third idler gears  351 ,  352  and  354 , as shown in  FIG. 3 . The frame  310  is connected to a feeding roller rotary shaft  321  to lift and lower the pickup roller  330  in association with rotation of the feeding roller  320 . According to this structure, when the feeding roller  320  is rotated in a first direction B ( FIG. 4 ) for feeding the document M, the pickup roller  330  is lowered in a direction D ( FIG. 4 ) for contacting an upper side of the document M. When the feeding roller  320  is rotated in a second direction C ( FIG. 5 ), that is opposite to the previous direction B, the pickup roller  330  is distanced from the document M in a direction E ( FIG. 5 ). The pickup unit  300  may be configured as a single module including the feeding roller  320 , the pickup roller  330 , the idler gears  351 ,  352 , and  354 , the restrainer  400 , and the lifting and lowering driver  360  that will be described hereinafter. As long as the feeding roller rotary shaft  321  of the feeding roller  320  is supportedly mounted in the main body  110 , the other rollers and gears may be normally operated. Therefore, the assembling process of the main body  110  may be simplified by configuring the pickup unit  300  as a single module.  
         [0039]     The restrainer  400  prevents contact between the leading end of the document M and the feeding roller  320  caused by stacking the document M carelessly in a standby mode in which the pickup roller  330  is lifted. The restrainer  400  is mounted to the pickup unit  300  to move up and down and has a stopper  410  and a guide part  420 . The stopper  410  descends when the pickup roller  330  is lifted and thereby blocks between the feeding roller  320  and the leading end of the document M, as shown in  FIG. 4 . The guide part  420  extends from one side of the stopper  410 . Ascending as the pickup roller  330  is lowered, the guide part  420  guides the upper side of the document M picked up by the pickup roller  330  between the feeding roller  320  and a friction member  290 , as shown in  FIG. 5 . The friction member  290  is provided to substantially prevent multi-sheet feeding. The stopper  410  and the guide part  420  are, for example, slanted with respect to each other. Referring to  FIG. 5 , an angle θ formed between the stopper  410  and the guide part  420  has, for example, a size such that an end  420   a  ( FIG. 3 ) of the guide part  420  directs documents M between the friction member  290  and the feeding roller  320 . The angle θ may be determined, for example, in consideration of varied positions of the restrainer  400  according to the descending of the pickup roller  330 .  
         [0040]     The restrainer  400  is moved up and down by the lifting and lowering driver  360  operated in association with rotation of the feeding roller  320 . In this exemplary embodiment, the lifting and lowering driver  360  includes a pinion  361  and a rack gear part  365 . The pinion  361  is rotatably supported by the frame  310  to be coaxially arranged with the second idler gear  352  for driving the pinion  361 . In an exemplary implementation, the second idler gear  352  is rotated in the same direction as the pickup roller  330 . The rack gear part  365  is formed at one side of the restrainer  400  facing the pinion  361  along an ascending and descending direction of the restrainer  400 , and engages with the pinion  361 . As shown in  FIG. 3 , a pinion rotary shaft  362  of the pinion  361  and an idler gear rotary shaft  353  of the second idler gear  352  are connected to each other through a spring clutch  367 . Accordingly, when the feeding roller  320  is rotated in the first direction B ( FIG. 4 ), the spring clutch  367  is compressed and therefore, the pinion  361  is rotated in association with driving of the second idler gears  352 . Consequently, the restrainer  400  is lifted. The restrainer  400  is lifted until a contacting portion  411  thereof is brought into contact with the frame  310 . In this exemplary embodiment, the restrainer  400  is lifted until the contacting portion  411  is stopped by an end of a guide groove  315  formed on an inner wall of the frame  310 . However, the present invention may be embodied in other various ways. For example, the restrainer  400  may be in another form so that lifting of the restrainer  400  may be restricted by contact thereof with a lower end of the frame  310 . Furthermore, another type of clutch may be used instead of the spring clutch  367  to connect the respective second idler gears  352  with the pinion  361  for selective power transmission. The guide groove  315  is formed on an inner wall of the frame  310  for sliding of a side edge of the restrainer  400 , so that the restrainer  400  may be lifted with the rack gear part  365  and the pinion  361  firmly meshed with each other. When the feeding roller  320  is stopped or rotated in the second direction C ( FIG. 5 ), the restrainer  400  descends by its own weight since the pinion  361  driven by the spring clutch  367  is stopped. The restrainer  400  descends until a lower end of the stopper  410  contacts a bottom surface  210   a  of the document tray  210 , which supports a lower side of the document M, as shown in  FIG. 4 .  
         [0041]     An exemplary embodiment of the present invention applied to the image scanning apparatus has been described so far. However, the present invention is not limited to this case but applicable for other various office electronic apparatuses requiring paper supply, such as a printer, a copier, and a facsimile.  
         [0042]     The operation of the paper feeding device according to an exemplary embodiment of the present invention will now be described with reference to  FIGS. 4 and 5 .  
         [0043]     In the standby mode in which the document M is not being fed, the restrainer  400  is in a lowered state, as shown in  FIG. 4 . Therefore, when stacking the sheets of document M, contact between the leading end of the document M and the feeding roller  320  is prevented. When the feeding roller  320  starts rotating in the first direction B to feed the document M, the pickup roller  330  is lowered in the arrowed direction D ( FIG. 4 ) and contacts the upper side of the document M, as shown in  FIG. 5 . When the pickup roller  330  is lowered, the restrainer  400  is lifted in an arrowed direction F ( FIG. 4 ) by reciprocal action of the rack gear  365  and the pinion  361  until an end of the guide part  420  directs sheets of document M between the feeding roller  320  and the friction member  290 . After the restrainer  400  is lifted and the pickup roller is lowered completely, the pickup roller  330  is rotated in the first direction B and feeds an uppermost sheet of the document M stacked on the document tray  210  to the feeding roller  320 . The upper side of the document M being fed by the pickup roller  330  is prevented by the guide part  420  of the restrainer  400  from being lifted over a predetermined height. The document M fed to the feeding roller  320  is fed to the paper feeding path  130  ( FIG. 2 ) by rotation of the feeding roller  320 . The feeding roller  320  is rotated until the detection sensor S 2  ( FIG. 2 ) senses the document M having been fed to a predetermined position.  
         [0044]     When the paper feeding by the feeding roller  320  is completed, the feeding roller  320  is rotated in the second direction C to lift the pickup roller  330  in an arrowed direction E ( FIG. 5 ) so that the pickup roller  330  is separated from the document M. At this time, as a driving force of the second idler gear  352  applied to the pinion  361  is removed, the restrainer  400  descends by its own weight in an arrowed direction G After the restrainer  400  is lowered and the pickup roller  330  is lifted completely, the respective parts are positioned as shown in  FIG. 4  and stand by in this state until feeding of another document M is required.  
         [0045]     According to an exemplary embodiment of the present invention as described above, contact of the document M stacked on the document tray  201  with the feeding roller  320  is restricted when the feeding roller  320  and the pickup roller  330  are not driven. According to this configuration, unintended contact between the document M and the feeding roller  320  while the document M is stacked on the document tray  201  may be prevented, thereby restraining damage of the document M by the feeding roller  320  being rotated for the paper feeding. Additionally, the upper side of the document M may be controlled by the guide member  420  when the restrainer  400  is lifted, thereby restraining damage of the document M by rotation of the feeding roller  320 , which is caused when the document M is incorrectly fed. Finally, deterioration of quality of printed image and read image may be prevented.  
         [0046]     While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.