Patent Publication Number: US-8992003-B2

Title: Recording medium feeding device and recording apparatus

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a recording medium feeding device and a recording apparatus including the same. 
     In the invention, the recording apparatus includes an ink jet printer, a line printer, a copy machine, a facsimile, and the like. 
     2. Related Art 
     In the related art, in a recording apparatus such as an ink jet printer, there is provided a recording medium feeding device that separates one sheet of recording media from a sheet feeding tray which supports a plurality of stacked recording media, and feeds it to a recording unit which performs a recording process, and the like. In the recording medium feeding device, there is provided a separating inclined portion that is inclined at a predetermined angle with respect to a surface on which the recording media in the sheet feeding tray is placed. The recording medium stacked on the sheet feeding tray comes into contact with a pick-up roller and then is fed out toward the separating inclined portion. At this time, leading edges of the recording media which are fed in a state in which a plurality of sheets is stacked one on top of another, come into contact with the inclined surface of the separating inclined portion and are subjected to the influence of a load (including a reaction force and a frictional force) in the direction opposite to the feeding direction. Thereby, the stacked recording media are separated by the separating inclined portion and finally, only one recording medium which is at the topmost position is fed out to the downstream side of a feeding path. 
     Incidentally, in the recording medium feeding device, the separating inclined portion is installed at a position opposing the leading edge of the recoding medium accommodated in the sheet feeding tray. Therefore, if the sheet feeding tray is forcefully inserted in a recording medium feeding device main body (hereinafter, referred to as a “device main body”), the recording medium is moved from an interior of the tray in the insertion direction due to an inertial force and thus is likely to ride on the inclined surface of the separating inclined portion. Therefore, there is a possibility that the recording medium feeding device may not separate the stacked recording media one by one and thus the stacked recording media may be fed as they are stacked one on top of another. In addition, even though the sheet feeding tray is slowly attached to the device main body, the recording medium may frequently ride on the inclined surface of the separating inclined portion. 
     Techniques for solving such a problem have been studied. For example, in JP-A-2011-132029, a stopper mechanism is installed at the position opposing the leading edge of the recording medium in the device main body. The stopper mechanism is configured to enable the displacement between a regulating state where the movement of the recording medium is regulated in the insertion direction of the sheet feeding tray when the sheet feeding tray is inserted to the device main body and a regulating release state where in a predetermined time after the sheet feeding tray is inserted, the regulating state is released, and the recording medium is able to be fed to the feeding path. 
     Incidentally, in the recording medium feeding device, an engaging portion is disposed in the vicinity of the stopper such that the engaging portion is engaged with the sheet feeding tray to switch the stopper from the regulating state to the regulating release state, and thus the state of the stopper is switched by a displacement operation of the engaging portion. However, in the configuration of the related art, since the engaging portion was disposed in the vicinity of the stopper, it was difficult to reduce the size of the stopper mechanism. 
     However, on the other hand, if the engaging portion is separated from the stopper, the engaging portion, that is a portion which receives a force from the sheet feeding tray, and the stopper, that is a portion which applies the reaction force with respect to the engaging portion, are separated from each other. Accordingly, due to the influence of a rotating moment, the displacement is made even whilst a force being applied to the engaging portion in a direction deflected with respect to an inherent displacement direction and thereby the engaging portion is unable to smoothly perform the displacement operation, that is, there is a possibility that switching the state of the stopper may not be performed. 
     SUMMARY 
     An advantage of some aspects of the invention is to provide a recording medium feeding device and a recording apparatus in which separating an engaging portion from a stopper no longer causes trouble in a switching operation of the stopper. 
     In addition, a sheet accommodating portion in which sheets are accommodated in a recording apparatus is referred to as various terms such as a “cassette” and a “tray”, however, in the present description, the term of the “tray” is used. 
     According to a first aspect of the invention, there is provided a recording medium feeding device including a feeding unit that feeds a recording medium; a tray that accommodates a recording medium, which is attachable to and detachable from a device main body including the feeding unit; a stopper that is able to switch between a regulating state in which the stopper comes into contact with a leading edge of the recording medium which is accommodated in the tray to regulate a movement of the recording medium, and a regulating release state in which the regulating state is released to enable the recording medium to be fed to a feeding path; and a switching unit that, is engaged with the tray to switch the stopper from the regulating state to the regulating release state when the tray is inserted into the device main body, wherein the switching unit includes engaging portions that are engaged with the tray, and wherein the engaging portions are disposed, being separated from the stopper, at both sides of the stopper in a width direction of the recording medium. 
     In this aspect, since the engaging portions are disposed at positions separated from the stopper, it is possible to reduce the size of the stopper and the switching unit of the stopper. In addition, when the tray and the engaging portions are engaged with each other, a force which acts on the engaging portions is applied to the stopper and the switching unit via the engaging portions which are disposed at both sides of the stopper. Therefore, it is possible to reduce the force applying to the engaging portions in the direction deflected with respect to a displacement direction thereof. 
     The switching unit may include a first biasing unit that biases the stopper in a direction of the stopper from the regulating state to the regulating release state in one side of the engaging portions between the engaging portions which are disposed at both sides of the stopper, a second biasing unit that biases the stopper in a switching direction of the stopper from the regulating state to the regulating release state in the other side of the engaging portions of the engaging portions which are disposed at both sides of the stopper, a third biasing unit that biases the stopper in a direction that switches the stopper from the regulating release state to the regulating state in one side of the engaging portions, and a fourth biasing unit that biases the stopper in a switching direction of the stopper from the regulating release state to the regulating state in the other side of the engaging portions. 
     In this case, since the switching unit is provided with the biasing units that bias the stopper in a switching direction from the regulating state to the regulating release state, and in the switching direction from the regulating release state to the regulating state, in the individual engaging portion, it is possible to reliably switch the stopper to an individual state. In addition, in the invention, the term “biasing the stopper” may also include either directly biasing the stopper or indirectly biasing the stopper via the other member. 
     An individual biasing force of the first biasing unit and the second biasing unit may be set to be decreased as a distance becomes longer, depending on the distance between the position at which the individual biasing unit biases the engaging portion and the stopper. 
     In this case, since the individual biasing force of the first biasing unit and the second biasing unit is set such that rotating moments which act on the one side of the engaging portions and the other side of the engaging portions are substantially similar to each other, it is possible to reduce the force applying to the engaging portions even in the direction deflected with respect to the displacement direction thereof. 
     An individual biasing force of the third biasing unit and the fourth biasing unit may be set to be decreased as the distance becomes longer, depending on the distance between the position at which the individual biasing unit biases the engaging portion and the stopper. 
     In this case, since the individual biasing force of the third biasing unit and the fourth biasing unit is set such that as the rotating moments which act on the one side of the engaging portions and the other side of the engaging portions are substantially similar to each other, it is possible to reduce a possibility that the engaging portion may be gouged. 
     According to a second aspect of the invention, there is provided a recording medium feeding device including a feeding unit that feeds a recording medium, a lower side tray that accommodates a recording medium, which is attachable to and detachable from a device main body including the feeding unit, an upper side tray that accommodates a recording medium, which is attachable to and detachable from the device main body and is located above a mounting position of the lower side tray when being mounted in the device main body, a stopper that is able to switch between a regulating state which comes into contact with a leading edge of the recording medium which is accommodated in the lower side tray to regulate a movement of the recording medium, and a regulating release state in which the regulating state is released to enable the recording medium to be fed to a sheet feeding path, and a switching unit that is engaged with the lower side tray to switch the stopper from the regulating state to the regulating release state when the lower side tray is inserted into the device main body, wherein the switching unit includes engaging portions that are engaged with the lower side tray, and wherein the engaging portions are disposed, being separated from the stopper, at both sides of the stopper in a width direction of the recording medium. 
     In this aspect, since the engaging portions are disposed at the positions separated from the stopper, it is possible to reduce the size of the stopper and the switching unit of the stopper. In addition, when the lower side tray and the engaging portion are engaged with each other, the force which acts on the engaging portions acts on the stopper and the switching unit via the engaging portions disposed at both sides of the stopper. Therefore, it is possible to reduce the force applying to the engaging portions in the direction deflected with respect to the displacement direction thereof. 
     The stopper may be formed at a height where the stopper is able to engage with the leading edge of the recording medium which is accommodated in the lower side tray, and at a height where the stopper does not engage with the recording medium which is accommodated in the upper side tray. 
     In this case, the size of the stopper may be reduced in the height direction of the recording apparatus and the size of the recording apparatus may be reduced in the height direction. 
     The recording medium feeding device may further include a braking mechanism that applies a braking force to the stopper when switching from the regulating state of the stopper to the regulating release state. 
     In this case, the switching operation of the stopper may be smoothly performed and thereby after the operation of the leading edge of the recording medium which is accommodated in the tray is reliably regulated, the stopper may be switched to the regulating release state. 
     The switching unit may include a first slider that is engaged with the stopper and is displaceable in an advancing and retreating direction with respect to the leading edge of the recording medium, a second slider that is displaceable together with the engaging portion in the advancing and retreating direction, and a connecting member that connects the first slider and the second slider together. 
     In this case, the switching unit is divided into the first slider, the second slider and the connecting member and thereby components may be easily molded so that a low cost is realized. 
     The connecting member may be molded by sheet metal working. 
     In this case, it is possible to increase the rigidity of the connecting member and also it is possible to decrease bending of the connecting member even though the distance is long between the position where the engaging unit is biased and the stopper. 
     According to a third aspect of the invention, there is provided a recording apparatus including a recording unit that performs recording on the recording medium; and any one of the recording medium feeding devices described above. 
     According to the third aspect, in the recording apparatus, it is possible to obtain the same operation effects as those in the first and second aspect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a side cross-sectional view of a printer according to the present invention when an upper side tray is located in a retreated position. 
         FIG. 2  is a side cross-sectional view of the printer according to the present invention when the upper side tray is located in an abutting position. 
         FIG. 3  is a perspective view illustrating a portion opposing a leading edge of a sheet which is accommodated in a lower side tray, in a sheet feeding device main body according to a first embodiment. 
         FIG. 4  is a perspective view illustrating a stopper mechanism in the first embodiment. 
         FIG. 5  is an exploded perspective view illustrating a configuration of the stopper mechanism in the first embodiment. 
         FIG. 6  is a plan view illustrating a disengaged state of the stopper mechanism in the first embodiment. 
         FIG. 7  is a plan view illustrating an engaged state between the stopper mechanism and the lower side tray in the first embodiment. 
         FIG. 8A  is a side view illustrating a regulating state of the stopper in the first embodiment, and  FIG. 8B  is a side view illustrating a regulating release state of the stopper in the first embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each embodiment, the same reference numerals will be given to the same configuration and description will be given only in the first embodiment, and in subsequent embodiments the description of the configuration will be omitted. 
       FIG. 1  is a side cross-sectional view of an ink jet printer (hereinafter, referred to as a “printer”)  10  according to one embodiment of the “recording apparatus” when an upper side tray is located in a retreated position.  FIG. 2  is a side cross-sectional view of the printer  10  when the upper side tray is located in an abutting position.  FIG. 3  is a perspective view illustrating a portion opposing a leading edge of a sheet which is accommodated in a lower side tray, in a sheet feeding device main body according to a first embodiment.  FIG. 4  is a perspective view illustrating a stopper mechanism in the first embodiment.  FIG. 5  is an exploded perspective view illustrating a configuration of the stopper mechanism in the first embodiment. 
     In addition,  FIG. 6  is a plan view illustrating a disengaged state of the stopper mechanism in the first embodiment.  FIG. 7  is a plan view illustrating an engaged state between the stopper mechanism and the lower side tray in the first embodiment.  FIG. 8A  is a side view illustrating a regulating state of the stopper in the first embodiment.  FIG. 8B  is a side view illustrating a regulating release state of the stopper in the first embodiment. 
     In addition, in  FIGS. 1 and 2 , almost all of rollers are illustrated on the same plane, so as to illustrate the rollers which are disposed on a sheet transportation path of a printer  10 . However, positions in the depth direction (frontward and backward directions from the sheet surface of  FIGS. 1 and 2 ) are not necessarily matched (in some cases, matched). In addition, in an X-Y-Z axis direction coordinate system illustrated in each drawing, an X axis direction indicates a direction perpendicular to a sheet transporting (feeding) direction, a Y axis direction indicates the sheet transporting direction (a sheet feeding direction), and a Z axis direction indicates a height direction of the device, that is, the direction of the gravity. 
     Hereinafter, with reference to  FIGS. 1 and 2 , the overall configuration of the printer  10  will be described. The printer  10  includes a recording medium feeding device (hereinafter, referred to as a “feeding device”)  12 , and has a configuration where a sheet of paper (mainly a single sheet: hereinafter, referred to as a “sheet P”) as an example of the “recording medium” is fed one by one from the recording medium feeding device, recording (ink jet recording) in a recording unit  14  is performed, and then the sheet P is discharged toward a sheet discharge stacker  16  which is installed at the front side ( FIGS. 1 and 2 , −Y axis direction) of the device. 
     Hereinafter, more detailed descriptions will be made with regard to configuration elements on a sheet transporting path. The feeding device  12  includes a lower side tray  50 , an upper side tray  60  which is located on the upper side thereof, a stopper mechanism  18 , a pick-up roller  20  and a first separating unit  22 . The lower side tray  50  and the upper side tray  60  as a sheet accommodating portion capable of setting a plurality of sheets P in a stacked state are respectively configured to be attachable to or detachable from the front side of feeding device  12 . In addition, the upper side tray  60  is driven in a sheet transporting direction ( FIGS. 1 and 2 , Y axis direction) by a motor (not illustrated) and is configured to be movable between an abutting position, that is, a position capable of feeding the sheet (refer to  FIG. 2 ) and a retreated position (refer to  FIG. 1 ) displaced from the abutting position by a predetermined displacement amount to the opposite side to the sheet transporting direction. 
     In addition, in  FIGS. 1 and 2 , the sheet accommodated in the lower side tray  50  is represented by the reference numeral P 1  and the sheet accommodated in the upper side tray  60  is represented by the reference numeral P 2 , respectively (hereinafter, referred to as the “sheet P” in a case where there is no need to specifically distinguish them). 
     A stopper mechanism  18  is installed at a position opposing the leading edge of the sheet P 1  which is accommodated in the lower side tray  50  in the feeding device  12 . The stopper mechanism  18  is configured to be switchable between a regulating state (refer to  FIG. 8A ) and a regulating release state (refer to  FIG. 8B ) by being engaged with the lower side tray  50 . When the stopper mechanism  18  is in the regulating state, the stopper mechanism  18  comes into contact with the leading edge of the sheet P 1  to regulate the movement of the sheet P 1 , and when the stopper mechanism  18  is in the regulating release state, the stopper mechanism  18  enables the sheet P 1  to move to a feeding path. The stopper mechanism  18  holds the regulating state when the lower side tray  50  is in a detached state. 
     A pick-up roller  20  is rotationally driven by a motor (not illustrated) and is installed on an oscillating member  26  which oscillates about the center of an oscillating axis  24 . The pick-up roller  20  rotates while coming into contact with the topmost sheet P 1  which is accommodated in the lower side tray  50  when the upper side tray  60  is slid in the furthest retreated direction ( FIGS. 1 and 2 , −Y axis direction), that is, when the upper side tray  60  is located at the retreated position (refer to  FIG. 1 ) and also when the stopper mechanism  18  is in the regulating release state, and thereby feeds the topmost sheet P 1  from the lower side tray  50  to the feeding path. 
     In addition, the pick-up roller  20  rotates while coming into contact with the topmost sheet P 2  which is accommodated in the upper side tray  60 , in the abutting position where the upper side tray  60  is slid in the deepest direction (sheet feeding direction:  FIGS. 1 and 2 , +Y axis direction) of the device, that is, in a position where the sheet feeding is possible (refer to  FIG. 2 ), and thereby feeds the topmost sheet P 2  from the upper side tray  60  to the feeding path. 
     In the feeding device  12 , a first separating unit  22  is installed at a position opposing the leading edges of the sheet P 1  which is set in the lower side tray  50  or at a position opposing the leading edges of the sheet P 2  which is set in the upper side tray  60 . The first separating unit  22  comes into contact with the leading edge of sheet P which is fed out from the lower side tray  50  or the upper side tray  60  by the rotation of the pick-up roller  20 , and in a state in which the sheet P is in contact with the first separating unit  22 , the sheet P is transported to a downstream side of the feeding path. Thereby, the topmost sheet P and the subsequent top sheet P are separated. 
     At the downstream side of the feeding path of the first separating unit  22 , a second separating unit  32  is installed, which is configured to include a separating roller  28  and a driving roller  30  driven by a motor (not illustrated) and separates the sheets P. In addition, at the downstream side of the feeding path of the second separating unit  32 , a driven roller  34  is installed, which is driven to rotate by pinching the sheet P with the driving roller  30 . In addition, at the downstream side of the feeding path of the driven roller  34 , a transportation unit  40  is installed, which is provided with a transportation driving roller  36  which is driven by a motor (not illustrated) and a transportation driven roller  38  which is driven to rotate while being in pressed contact with the transportation driving roller. The sheet P is fed to the further downstream side by the transportation unit  40 . 
     At the downstream side of the transportation unit  40 , a recording unit  14  is installed. The recording unit  14  is provided with a recording head  42  and a lower guide member  44  which opposes the recording head. The recording head  42  opposes the sheet P, being installed at the bottom portion of a carriage  46 . The carriage  46  is driven to reciprocate in a main scanning direction (frontward and backward directions from the sheet surface of  FIG. 1 , that is, X axis direction) by a driving motor (not illustrated). 
     The lower guide member  44  supports the sheet P and defines a distance between the sheet P and the recording head  42 . Then, at the downstream side of the lower guide member  44 , a discharge unit  48  is installed, which discharges the sheet P on which the recording has been performed. The discharge unit  48  is provided with a discharge driving roller  52  which is driven by a motor (not illustrated) and a discharge driven roller  54  that comes into contact with the discharge driving roller and is driven to rotate. The sheet P on which the recording is performed by the recording unit  14  is pinched by the discharge unit  48  and is discharged to the sheet discharge stacker  16  which is installed at the front side of the device. In addition, the sheet discharge stacker  16  is configured to be extractable to the front side of the device. 
     In addition, in a case where the recording is performed on both surfaces of the sheet P in the printer  10 , the recording is performed on the first surface of the sheet P by the recording unit  14 , and thereafter, the sheet P is returned to an upstream side of the transportation unit  40  so that a trailing edge of the sheet when the recording has been performed on the first surface becomes the leading edge by a reverse operation of the transportation unit  40  and the discharge unit  48 . Then, the sheet P is further fed to an inversing path  56  by the reverse operation of the transportation unit  40 . The sheet P which is fed to the inversing path  56  is pinched by the driving roller  30  and an inverse roller  58  and is returned to the feeding path again. 
     The sheet P which is returned to the feeding path is fed again to the transportation unit  40  at the downstream side of the feeding path by the driving roller  30  through the separating roller  28  and the driven roller  34 . At this time, the first surface and the second surface of the sheet P are curved to be reversed to the second surface and then oppose the recording head  42 . The sheet P is fed to the recording unit  14  by the transportation unit  40 . The sheet P on which the recording of the second surface has been performed by the recording unit  14  is pinched by the discharge unit  48  and then is discharged to the sheet discharge stacker  16  that is installed on the front side of the device. 
     Referring to  FIG. 3 , in the sheet feeding device  12 , a portion  12   a  (hereinafter, referred to as an “opposing portion”) which opposes the leading edge of the sheet P 1  which is accommodated in the lower side tray  50  and the leading edge of the sheet P 2  which is accommodated in the upper side tray  60  is illustrated. The opposing portion  12   a  is configured by the stopper mechanism  18  that regulates the movement of the sheet P 1  and the first separating unit  22  that separates the sheets P. 
     The first separating unit  22  is provided with a plurality of first separating inclined surfaces  62  and a plurality of second separating inclined surfaces  64  that extend along with the sheet feeding path. The second separating inclined surfaces  64  have a height different from the first separating inclined surfaces  62  in the height direction of the recording apparatus. The first separating inclined surfaces  62  are disposed with an appropriate space in the X axis direction in the opposing portion  12   a , and oppose the sheet P 1  which is accommodated in the lower side tray  50  and the sheet P 2  which is accommodated in the upper side tray  60 . 
     The second separating inclined surfaces  64  are set so that their height is lower than the lower side of the upper side tray  60 . That is, the second separating inclined surfaces  64  do not oppose the leading edge of the sheet P 2  which is accommodated in the upper side tray  60 . For this reason, when the sheet P 1  which is accommodated in the lower side tray  50  is fed, the first separating inclined surfaces  62  and the second separating inclined surfaces  64  come into contact with the leading edge of the sheet P 1  and thus separate the sheets P 1 . 
     When the sheet P 2  which is accommodated in the upper side tray  60  is fed, the first separating inclined surfaces  62  come into contact with the leading edges of the sheets P 2  and separates the sheets P 2 . Accordingly, the first separating unit  22  is able to change the separating conditions in conjunction with the sheets P 1  which are accommodated in the lower side tray  50  or the sheet P 2  which is accommodated in the upper side tray  60  by changing the number of the separating inclined surfaces which come into contact with the leading edge of the sheet and thereby it is possible to allow optimum separating conditions in conjunction with the sheets P 1  and P 2  respectively. 
     First Embodiment 
     The stopper mechanism  18  is provided with a stopper  66  that is disposed in the vicinity of the center of the X axis direction in the opposing portion  12   a  and a switching unit  68  that switches the stopper  66  from the regulating state to the regulating release state. In a state in which the first separating unit  22  is attached to the opposing portion  12   a , the switching unit  68  has the upward and forward sides (−Y axis direction) covered by the first separating unit  22 . 
     The switching unit  68  is provided with engaging portions  70  and  72  that are disposed with a distance in the X axis direction from the stopper  66  at both sides of the stopper  66 . The engaging portions  70  and  72  are disposed in openings  73  and  73  that are installed at positions pinched by the first separating inclined surfaces  62  of the first separating unit  22 . In addition, the engaging portions  70  and  72  are configured to be displaceable in the Y axis direction with respect to the opposing portion  12   a  and when being in a disengaging state with the lower side tray  50 , is protruded further than the first separating unit  22  in the −Y axis direction. Hereinafter, the stopper mechanism  18  will be described in more detail with reference to  FIGS. 4 and 5 . 
     The switching unit  68  is provided with a cam slider  74  that is engaged with the stopper  66  as a “first slider” and is displaceable in the Y axis direction, the first engaging portion  70  that is disposed with a distance in the X axis direction from the stopper  66 , the second engaging portion  72  that is disposed with a distance in the −X axis direction from the stopper  66 , a first engaging slider  78  that is displaceable in the Y axis direction together with the first engaging portion  70  as a “second slider”, and a second engaging slider  80  that is displaceable in the Y axis direction together with the second engaging portion  72  as the “second slider”. 
     In addition, the switching unit  68  is provided with a first connecting member  82  that connects a cam slider  74  and the first engaging slider  78  as a “connecting member”, a second connecting member  84  that connects a cam slider  74  and the second engaging slider  80  as a “connecting member”, a coil spring  88  as a “first biasing unit” and a coil spring  86  as a “third biasing unit” that are disposed at the first engaging portion  70  side, and a coil spring  92  as a “second biasing unit” and a coil spring  90  as a “fourth biasing unit” that are disposed at the second engaging portion  72  side. 
     At the lower end of the stopper  66 , a stopper rotating axis  94  that extends in the X axis direction is installed. The stopper rotating axis  94  is fitted with a hook-shaped bottom engaging portion  96  that is installed at the bottom surface  76  of the opposing portion  12   a . In the upper side of the stopper rotating axis  94 , a regulating portion  98  for regulating the movement of the sheet P 1  is installed. In the regulating portion  98 , a regulating surface  100  which comes into contact with the leading edges of the sheets P 1  is formed and then a pair of side walls  102  that extends in the Y axis direction from both sides of the regulating surface  100  in the X axis direction is installed. On a pair of the side walls  102 , engaging pins  104  that are protruded in the X axis direction from the side walls and oppose each other are installed. 
     The cam slider  74  is provided with a main body  106 , a stopper engaging portion  108  that is protruded in the Z axis direction from the main body  106 , and a pair of connecting portions  110  that is protruded to both sides in the X axis direction from the main body  106  to be extended in the X axis direction. In the main body  106 , a first sliding portion  112  is installed. The first sliding portion  112  is formed with concave portions and convex portions such that when the Y axis direction is set to a sliding direction, the shape of the cross section intersecting the sliding direction, that is, the cross section in the X axis direction comes to have a concave and convex shape (so called, comb-teeth shape) that concave and convex portions are repeatedly formed in the X axis direction. In addition the concave and convex portions are extended along the Y axis direction. 
     In addition, a second sliding portion  114  that is fitted to the first sliding portion  112  is installed at the bottom  76  of the opposing portion  12   a . In the second sliding portion  114 , the cross section in the X axis direction comes to have a concave and convex shape (so called, a comb-teeth shape) that concave and convex portions are repeatedly formed in the X axis direction. In addition, the concave and convex portions of the second sliding portion  114  extend along the Y axis direction to be formed longer than the concave and convex portions of the first sliding portion  112  in the Y axis direction. 
     The first sliding portion  112  and the second sliding portion  114  have their mutual concave and convex portions slidably fitted to each other through a viscous material (such as grease). That is, the cam slider  74  is slidably configured in the Y axis direction with respect to the bottom surface  76  of the opposing portion  12   a . In addition, the first sliding portion  112  and the second sliding portion  114  configure a braking mechanism  115  that applies a braking force to the cam slider  74  in the Y axis direction. 
     In the stopper engaging portion  108 , slit-shaped engaging space  116  with a predetermined width (refer to  FIGS. 8A and 8B ) which penetrates in the X axis direction and has an opening end in the −Y axis direction side is provided so as to be diagonally inclined downwardly in the −Y axis direction. The engaging pins  104  of the stopper  66  are engaged with the engaging space  116 . The connecting portions  110  are connected to the opposing first engaging slider  78  via the first connecting member  82  or to the second engaging slider  80  via the second connecting member  84 . 
     The first engaging portion  70  is provided with a main body  118  and an engaging protrusion portion  120  that is protruded from the main body  118  in the −Y axis direction. In addition, the first engaging portion  70  has the end portions  122  of both sides in the X axis direction of the main body  118  engaged with a pair of the sliding paths  124  installed on the bottom surface  76  of the opposing portion  12   a  and is configured to be slidable in the Y axis direction while the engagement state is held. One end of the coil spring  86  that is the third biasing unit is supported by or fixed to the rear surface of the main body  118 . The other end of the coil spring  86  is fixed to or supported by the rear surface  126  of the opposing portion  12   a . The coil spring  86  biases the first engaging portion  70  in the −Y axis direction. 
     In addition, a concave portion  128  is installed in the main body  118 . A coil spring  88  is stored in the concave portion  128  and one end of the coil spring  88  is fixed to or supported by the main body  118 . The other end of the coil spring  88  is fixed to or supported by the first engaging slider  78 . That is, the first engaging portion  70  and the first engaging slider  78  are connected to each other by the coil spring  88  that is the first biasing unit. In addition, the coil spring  86  and the coil spring  88  are disposed in parallel to be expandable and contractible along the Y axis direction. 
     The first engaging slider  78  is configured by a main body  130  and a connecting portion  132 . The coil spring  88  that is supported by or fixed to the main body  118  of the first engaging portion  70  is connected to the main body  130 . In addition, the lower portion of the main body  130  is formed in conjunction with an outer shape of the main body  118  of the first engaging portion  70  with a cross-sectional shape in the X axis direction so that the main body  118  of the first engaging portion  70  is slidable with respect to the main body  130 . The connecting portion  132  extends toward the cam slider  74  from the main body  130  in the X axis direction. The connecting portion  132  is connected to the connecting portion  110  of the cam slider  74  via the first connecting member  82 . 
     The first connecting member  82  is formed from a metal material by sheet metal working (such as press working) and extends along the X axis direction. The first connecting member  82  connects the connecting portion  110  of the cam slider  74  and the connecting portion  132  of the first engaging slider  78 , and covers the upper surface and the side surface of the connecting portions  110  and  132  along the X axis direction so that the connecting portions  110  and  132  are reinforced. Thereby, it is possible to decrease bending in the connecting portions  110  and  132  when the cam slider  74  is displaced. Further, the first connecting member  82  may be formed by the sheet metal working (such as the press working) to achieve the reduced cost. 
     Configurations of the second engaging portion  72 , the second engaging slider  80 , the second connecting member  84  and the coil spring  90  that is the fourth biasing unit, and the coil spring  92  that is the second biasing unit are the same as those of the first engaging portion  70 , the first engaging slider  78 , the first connecting member  82 , and the coil springs  86  and  88 . Therefore the description thereof will be omitted. 
     In addition, the coil springs  88  and  92  are configured to act on the stopper  66  when the stopper  66  is displaced from the regulating state to regulating release state. Further, the coil springs  86  and  90  are configured to act on the stopper  66  when the stopper  66  is displaced from the regulating release state to the regulating state. Hereinafter, the displacement of the stopper  66  from the regulating state to the regulating release state or from the regulating release state to the regulating state will be described in detail together with the operations of the coil springs  86 ,  88 ,  90  and  92 . 
     Referring to  FIG. 6 , the first engaging portion  70  is disposed with a distance L 1  from the stopper  66 . On the other hand, the second engaging portion  72  is disposed with a distance L 2  from the stopper  66 . The distance L 2  is set to be longer than the distance L 1 . Therefore, if a biasing force (spring force F 4 ) of the coil spring  90  that is the fourth biasing unit which biases the second engaging portion  72  is set to be the same size force as the biasing force (spring force F 3 ) of the coil spring  86  that is the third biasing unit which biases the first engaging portion  70 , or is set to be a stronger force than the spring force F 3 , the rotation moment N 4  which acts on the second engaging portion  72  is greater than the rotation moment N 3  which acts on the first engaging portion  70 . Thereby, when the stopper mechanism  18  is viewed from the direction Z toward the direction −Z, the stopper mechanism  18  is displaced clockwise around the axis of the cam slider  74  and a force is applied to the first sliding portion  112  and the second sliding portion  114  in a direction deflected with respect to the sliding direction. 
     For this reason, in the present embodiment, the spring force F 3  of the coil spring  86  that is the third biasing unit and the spring force F 4  of the coil spring  90  that is the fourth biasing unit which biases the second engaging portion  72  are set to be decreased in proportion to the distance from the stopper  66  (as the distances become longer), in comparing the distance L 1  with the distance L 2 . More specifically, the rotation moment N 3  (=F 3 ×L 1 ) which acts on the first engaging portion  70  and the rotation moment N 4  (=F 4 ×L 2 ) which acts on the second engaging portion  72  are set to be substantially the same. Such a relationship allows that the rotation moments N 3  and N 4  which act on the first engaging portion  70  and the second engaging portion  72  are balanced with each other, and thereby the forces are unlikely to be applied to the first sliding portion  112  and the second sliding portion  114  in the directions deflected with respect to the sliding directions. 
     Referring to  FIG. 7 , when the stopper  66  is displaced from the regulating state to the regulating release state, the coil spring  88  that is disposed between the first engaging portion  70  and the first engaging slider  78  is compressed to generate the spring force F 1 . In addition, the coil spring  92  that is disposed between the second engaging portion  72  and the second engaging slider  80  is also compressed to generate the spring force F 2 . 
     The biasing force of the coil spring  88 , that is, the spring force F 1  biases the first engaging slider  78  in Y axis direction. At this time, the rotation moment N 1  (=F 1 ×L 1 ) acts on the first engaging slider  78 . In addition, the biasing force of the coil spring  92 , that is, the spring force F 2  biases the second engaging slider  80  in the Y axis direction. At this time, the rotation moment N 2  (=F 2 ×L 2 ) acts on the second engaging slider  80 . 
     Therefore, if the spring force F 2  of the coil spring  92  that biases the second engaging slider  80  is set to be the same size force as the spring force F 1  of the coil spring  88  that biases the first engaging slider  78  or is set to be a stronger force, the rotation moment N 2  which acts on the second engaging slider  80  is greater than the rotation moment N 1  which acts on the first engaging slider  78 . Thereby, when the stopper mechanism  18  is viewed from the direction Z toward the direction −Z, the stopper mechanism  18  is displaced clockwise around the axis of the cam slider  74 , and thus forces are applied to the first sliding portion  112  and the second sliding portion  114  in directions deflected with respect to the sliding directions. 
     For this reason, in the present embodiment, the spring force F 1  of the coil spring  88  that is the first biasing unit and the spring force F 2  of the coil spring  92  that is the second biasing unit which biases the second engaging portion  72  are set to be decreased in proportion to the distance from the stopper  66  (as the distances become longer), in comparing the distance L 1  with the distance L 2 . More specifically, the rotation moment N 1  (=F 1 ×L 1 ) which acts on the first engaging portion  70  and the rotation moment N 2  (=F 2 ×L 2 ) which acts on the second engaging portion  72  are set to be substantially the same. Such a relationship allows that the rotation moments N 1  and N 2  which act on the first engaging slider  78  and the second engaging slider  80  are balanced with each other, and thereby the forces are unlikely to be applied to the first sliding portion  112  and the second sliding portion  114  in the directions deflected with respect to the directions. 
     Here, the displacement of the stopper mechanism  18  from the regulating state to the regulating release state will be described with reference to  FIGS. 6 and 7 . In FIG.  6 , the stopper mechanism  18  is in the regulating state. The leading edges of the engaging protrusion portions  120  from the first engaging portion  70  and the second engaging portion  72  are placed at an engaging release position Y 1  in the Y axis direction, respectively. 
     In  FIG. 7 , if the lower side tray  50  is inserted from the front side of the opposing portion  12   a , that is, in the −Y axis direction, the leading edge  50   a  of the lower side tray  50  comes into contact with the leading edges of the engaging protrusion portions  120  of the first engaging portion  70  and the second engaging portion  72 . If the lower side tray  50  is pushed toward the opposing portion  12   a , the first engaging portion  70  and the second engaging portion  72  are pushed in the Y axis direction against the biasing force of the coil springs  86  and  90 . Thereby, the leading edges of the engaging protrusion portions  120  of the first engaging portion  70  and second engaging portion  72  are displaced to an engaging position Y 2 . At this time, by the operation of the braking mechanism  115 , the cam slider  74  does not move immediately, the coil spring  88  that is disposed between the first engaging portion  70  and the first engaging slider  78  and the coil spring  92  that is disposed between the second engaging portion  72  and the second engaging slider  80  remain in a compressed state for the time being. 
     The compressed coil springs  88  and  92  generate the spring force F 1  of the coil spring  88  and the spring force F 2  of the coil spring  92 , along the Y axis direction. Accordingly, the generated spring forces F 1  and F 2  cause the cam slider  74  to move (slide) together with the first engaging slider  78  and the second engaging slider  80  in the Y axis direction. The braking force of the braking mechanism  115  acts on the movement, and thereby the cam slider  74  slowly moves in the Y axis direction at a speed corresponding to the difference between the spring forces F 1  and F 2  and the braking force. Therefore, in the stopper mechanism  18 , the stopper  66  that is operated in link with the cam slider  74  using the cam mechanism is slowly rotated to move from the regulating position to the regulating release position due to the action of the braking force rendered by the braking mechanism  115 . Therefore, the stopper  66  reliably regulates the movement of the sheet P 1  in the Y axis direction and thereafter, is displaced to the regulating release state. 
     Next, the displacement of the stopper  66  from the regulating state to the regulating release state will be described with reference to  FIGS. 8A and 8B . In  FIG. 8A , the stopper  66  is in the regulating state. In  FIG. 8A , the cam slider  74 , and the stopper  66  that is engaged with the cam slider  74  via the engaging space  116  and the engaging pin  104  are biased by the coil springs  86  and  90 , toward a bottom surface engaging portion  96  via the first engaging portion  70 , the second engaging portion  72 , the first connecting member  82  and the second connecting member  84 , that is, in the −Y axis direction. At this time, the stopper  66  is in a state in which the regulating portion  98  is upstanding with respect to the bottom surface  76  of the opposing portion  12   a  and its regulating surface  100  opposes the leading edge of the sheet P 1  in the lower side tray  50 . Therefore, the regulating surface  100  comes into contact with the leading edge of the sheet P 1  and thus it is possible to regulate the movement in the Y axis direction. 
     As illustrated in  FIG. 8B , when the engaging protrusion portion  120  of the second engaging portion  72  (first engaging portion  70 ) comes into contact with the leading edge  50   a  of the lower side tray  50  and is pushed by the lower side tray  50  in the Y axis direction and thus is displaced to the engaging position Y 2 , the cam slider  74 , as described above, is slowly displaced in the Y axis direction, being delayed by the movement of the first engaging portion  70  and the second engaging portion  72 . At this time, the stopper  66  is rotated centering the stopper rotating axis  94  and is operated so that the engaging pin  104  moves into the engaging space  116  and then the regulating surface  100  faces a Y axis direction side. Thereby, the regulating surface  100  releases the regulation of the leading edge of the sheet P 1  as illustrated in  FIG. 8B . 
     In addition, in  FIG. 8B , the regulating surface  100  that is in the regulating release state is displaced in the Y axis direction side further than the first separating inclined surface  62  and the second separating inclined surface  64  of the first separating unit  22  in order not to disturb the feeding of the sheet P 1 . In addition, the stopper  66 , as illustrated in  FIGS. 8A and 8B , is lower than the upper side tray  60  in the height of the Z axis direction. Therefore, the stopper  66  does not disturb the feeding of the sheet P 2  which is accommodated in the upper side tray  60 . 
     In addition, as illustrated in  FIGS. 8A and 8B , when the leading edge  50   a  of the lower side tray  50  which is in contact with the engaging protrusion portion  120  of the second engaging portion  72  (first engaging portion  70 ) is displaced from the engaging position Y 2  to the engaging release position Y 1 , the coil springs  86  and  90  bias the first engaging portion  70  and the second engaging portion  72  in the −Y axis direction using their biasing forces. Thereby, the leading edges of the engaging protrusion portions  120  of the first engaging portion  70  and the second engaging portion  72  are displaced from the engaging position Y 2  to the engaging release position Y 1 . 
     Therefore, the first engaging portion  70  and the second engaging portion  72 , and the first engaging slider  78  and the second engaging slider  80  that are respectively connected via the coil springs  88  and  92  are displaced in the −Y axis direction. Thereby, the stopper  66  is biased by the coil springs  88  and  92  in the −Y axis direction via the first engaging portion  70 , the second engaging portion  72 , the first connecting member  82 , the second connecting member  84  and the cam slider  74 , and thus is displaced from the regulating release state to the regulating state. That is, the coil springs  86  and  90  causes the stopper  66  to be displaced from the regulating release state to the regulating state. 
     Modified Example of First Embodiment 
     In addition, the first embodiment described above may be further modified as below. 
     (1) In the above embodiment, the lower side tray  50  and the upper side tray  60  are separately configured. However, the lower side tray  50  and the upper side tray  60  may be integrated with each other and both trays may be integrally configured to be attachable to and detachable from the device main body. In this case, the upper side tray  60  is provided so as to be slidable with respect to the lower side tray  50 . 
     (2) In addition, in the above embodiment, the sheet feeding tray is configured in two stages, but it may be configured in only a single stage. 
     (3) The distance L 1  between the stopper  66  and the first engaging portion  70  may be set to be longer than the distance L 2  between the stopper  66  and the second engaging portion  72 , and may be set to be the same. In this case, the spring forces (biasing forces) F 1  and F 2  are set so that the rotation moments N 1  and N 2  are the same, and the spring forces (biasing forces) F 3  and F 4  are set so that the rotation moments N 3  and N 4  are the same. In addition, it is desirable that the rotation moments N 1  and N 2  or the rotation moments N 3  and N 4  respectively be the same. However, if the forces in the deflected direction are reduced, they may not be the same. 
     (4) The engaging protrusion portion  120  of the first engaging portion  70  and the second engaging portion  72  may be configured to be engaged with the upper side tray  60 , instead of being engaged with the lower side tray  50 . 
     (5) The first biasing unit, the second biasing unit, the third biasing unit and the fourth biasing unit may employ an air pressure and hydraulic pressure, instead of the coil springs  86 ,  88 ,  90  and  92 . 
     (6) The respective ends of the third biasing unit and the fourth biasing unit may be fixed to or supported by the first engaging slider  78  and the second engaging slider  80 , instead of the first engaging portion  70  and the second engaging portion  72 . 
     (7) The cam slider  74 , the first engaging slider  78 , the second engaging slider  80 , the first connecting member  82  and the second connecting member  84  may be integrally molded. 
     In addition, in the present embodiment, the feeding device  12  according to the invention is adopted to the ink jet printer as an example of the recording apparatus, but it may be adopted to the other general liquid ejecting apparatuses. 
     Here, the liquid ejecting apparatus is not limited to a recording apparatus such as a printer in which an ink jet type recording head is used and an ink is ejected from the recording head so that the recording is performed on the recording medium, a copy machine and a facsimile, and may include an apparatus which ejects a liquid corresponding to the use thereof, instead of the ink, is ejected from the liquid ejecting head equivalent to the ink jet type recording head onto the ejecting medium equivalent to the recording medium, and adheres the ejected liquid to the recording medium. 
     As the liquid ejecting head, in addition to the recording head, a color material ejecting head which is used for manufacturing a color filter of a liquid crystal display and the like, an electrode material (conductive paste) ejecting head which is used for forming an electrode of an organic EL display, a field emission display (FED) and the like, a bio-organic material ejecting head which is used for manufacturing a biochip, and a sample ejecting head as a precision pipette, and the like are exemplified. 
     In addition, it is to be understood that the invention is not limited to the above embodiments, but within the scope of the invention described in claims, various modifications are possible, which are also included within the scope of the present invention. 
     The entire disclosure of Japanese Patent Application No. 2012-069212, filed Mar. 26, 2012, is expressly incorporated by reference herein.