Patent Publication Number: US-10315869-B2

Title: Sheet feeding device and image forming apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC § 119 from Japanese Patent Application No. 2017-185370 filed Sep. 26, 2017. 
     BACKGROUND 
     Technical Field 
     The present invention relates to a sheet feeding device and an image forming apparatus. 
     Related Art 
     In a sheet feeding device of an image forming apparatus, in some cases, a contact section that contacts sheets stacked on a sheet stacking section and a releasing section that releases the contact by the contact section are provided in addition to a feeding section for feeding the sheets. 
     SUMMARY 
     According to an aspect of the present invention, there is provided a sheet feeding device including: a feeding unit that is provided to be movable in a forward-backward direction to move forward or backward relative to a sheet placing unit on which a sheet is placed, and feeds the sheet; a moving unit that moves the feeding unit in the forward-backward direction; a contact unit that is provided to be movable, with which the sheet placed on the sheet placing unit is brought into contact; a limitation unit that limits movement of the contact unit; and a releasing unit that, when the moving unit moves the feeding unit in a direction away from the sheet placing unit, with the movement of the feeding unit, releases limitation on the movement of the contact unit by the limitation unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
         FIG. 1  is an overall view of an image forming apparatus of the exemplary embodiment; 
         FIG. 2  is an overall perspective view of a second sheet supply section of the exemplary embodiment; 
         FIG. 3  is an overall perspective view of a sheet feeding section of the exemplary embodiment; 
         FIG. 4  is a plan view of the sheet feeding section of the exemplary embodiment; 
         FIG. 5  is an illustration diagram of a regulation section of the exemplary embodiment; 
         FIG. 6  is an illustration diagram that illustrates a relationship among a feeding section, the regulation section and a second drive section of the exemplary embodiment; 
         FIGS. 7A to 7D  are illustration diagrams of operations of a supporter of the exemplary embodiment; 
         FIG. 8  is a relationship diagram of the supporter and the regulation section at a releasing position; 
         FIG. 9  is a relationship diagram of the supporter and the regulation section moving toward the releasing position; 
         FIG. 10  is a relationship diagram of the supporter and the regulation section at a feeding position; 
         FIG. 11  is a relationship diagram of the supporter and the regulation section moving toward a standby position; and 
         FIGS. 12A to 12C  are illustration diagrams of the sheet feeding section in a modified example. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an exemplary embodiment according to the present invention will be described in detail with reference to attached drawings. 
     [Image Forming Apparatus  1 ] 
       FIG. 1  is an overall view of an image forming apparatus  1  of the exemplary embodiment. 
     The image forming apparatus  1  includes: an image forming section  10  that forms an image corresponding to image data of each color; an image reading device  20  that reads an image of an original; a sheet transport system  30  that transports sheets P; and a first sheet supply section  40  that supplies the sheets P to the image forming section  10 . Moreover, the image forming apparatus  1  includes: a second sheet supply section  50  (an example of a sheet feeding device) that supplies the sheets P to the image forming section  10 ; and a main body housing section  60  that contains the image forming section  10 , the sheet transport system  30  and the first sheet supply section  40 . 
     Note that, in the following description, a direction of a front side and a back side on the page of the image forming apparatus  1  shown in  FIG. 1  is referred to as a front-back direction D. Moreover, a description will be given while assuming that a horizontal direction on the page of the image forming apparatus  1  shown in  FIG. 1  is a horizontal direction H and a vertical direction on the page is a vertical direction V. 
     The image forming section  10  is provided with four image forming units  11  ( 11 Y,  11 M,  11 C and  11 K) disposed in parallel at regular intervals. Each of the image forming units  11 Y,  11 M,  11 C and  11 K includes a photoconductive drum  12  that forms an electrostatic latent image and carries a toner image, to thereby forms the toner image by the so-called electrophotographic system. The image forming units  11 Y,  11 M,  11 C and  11 K form toner images of yellow (Y), magenta (M), cyan (C) and black (K), respectively. 
     Moreover, the image forming section  10  includes an intermediate transfer belt  13  onto which the toner image of each color formed on the photoconductive drum  12  of each image forming unit  11  is transferred. Moreover, the image forming section  10  includes a primary transfer roll  14  that sequentially transfers (primarily transfers) toner images of respective colors formed in the image forming units  11  onto the intermediate transfer belt  13 . Further, the image forming section  10  includes: a secondary transfer section  15  that collectively transfers (secondarily transfers) the toner images of the respective colors overlapped to be formed on the intermediate transfer belt  13  onto the sheet P; and a fixing section  16  that fixes the toner images of the respective colors having been secondarily transferred to the sheet P. 
     The image reading device  20  transmits read image data to a controller of the image forming section  10  or a device outside of the image forming apparatus. Moreover, the image reading device  20  includes an original feeding device  21  that sequentially feeds originals stacked on a stacking section  21 S one by one to a reading sensor for causing the sensor to read images on the originals. 
     The sheet transport system  30  includes: a first transport path  31  that transports the sheets P supplied from the first sheet supply section  40  toward the secondary transfer section  15 ; a second transport path  32  that transports the sheets P supplied from the second sheet supply section  50  toward the secondary transfer section  15 ; a third transport path  34  that transports the sheets P from the secondary transfer section  15  to the fixing section  16 ; and a fourth transport path  35  that inverts the sheets P passed through the fixing section  16  and transports the sheets P to the secondary transfer section  15  again. 
     The first sheet supply section  40  includes plural sheet container sections  41 . Moreover, each of the sheet container section  41  has a feed-out roll  42  that feeds out the sheets P that are contained. Then, the first sheet supply section  40  feeds out the sheets P from each of the sheet container section  41  and supplies the sheets P toward the sheet transport system  30 . 
     &lt;Second Sheet Supply Section  50 &gt; 
       FIG. 2  is an overall perspective view of a second sheet supply section  50  of the exemplary embodiment. 
     As shown in  FIG. 2 , the second sheet supply section  50  includes: a sheet section  51  on which the sheets P are placed; and a sheet feeding section  80  that feeds the sheets P placed on the sheet section  51  toward the image forming section  10 . 
     The second sheet supply section  50  is a so-called manual feed tray. The second sheet supply section  50  is, when a user is going to form an image on a sheet P of an arbitrary size, a component on which the sheets P of the arbitrary size are set to be supplied to the image forming section  10 . The second sheet supply section  50  of the exemplary embodiment is able to supply sheets sizes of which ranges from, for example, a relatively small-sized sheet, such as a postcard, to a nonstandard-sized sheet up to A3 size, for example, toward the image forming section  10 . 
     Moreover, as shown in  FIG. 2 , the sheet feeding section  80  includes: a sensor  98  that senses presence or absence of the sheets P on a sheet stacking surface  52 P; and a cover  99  that covers various kinds of components in the sheet feeding section  80 . 
     The sensor  98  is disposed on a downstream side in the sheet feeding direction (in the exemplary embodiment, the horizontal direction H) in the sheet section  51 . Moreover, the sensor  98  is rotatably supported, and, when the sheets P are placed on the sheet stacking surface  52 P, the end portion of the sheets P on the downstream side in the feeding direction thereof can be brought into contact with the sensor  98 . Then, the sensor  98  is able to sense the presence or absence of the sheets on the sheet stacking surface  52 P in response to a rotating angle of itself. 
     The cover  99  is fastened to the main body housing section  60  (refer to  FIG. 1 ). The cover  99  covers components subjected to moving operations, such as roll members. 
     [Sheet Section  51 ] 
     The sheet section  51  includes: a sheet stacking section  52  on which the sheets P are placed (an example of a sheet placing unit); an expansion section  55  that expands the surface to place the sheets P in addition to the sheet stacking section  52 ; and a sheet guiding section  70  that guides the sheets P toward the sheet feeding section  80 . 
     Note that the sheet section  51  of the exemplary embodiment is provided rotatably so that the sheet stacking surface  52 P, which will be described later, can be positioned in an open state of facing upward in the vertical direction V or in a closed sate of facing the side portion of the main body housing section  60  (refer to  FIG. 1 ). 
     [Sheet Stacking Section  52 ] 
     The sheet stacking section  52  includes the sheet stacking surface  52 P facing upward in the vertical direction V. Then, the sheet stacking section  52  forms a location, where a sheet bundle (sheets P) to be fed by the sheet feeding section  80  is placed, on the sheet stacking surface  52 P. Moreover, in the exemplary embodiment, the sheet feeding direction in which the sheets P are fed in the sheet stacking section  52  is the horizontal direction H. 
     Note that, in the sheet stacking section  52  of the exemplary embodiment, the width in the front-back direction D corresponds to the length of the A4-size sheet. Moreover, in the sheet stacking section  52 , the width in the horizontal direction H corresponds to the width of the A4-size sheet. 
     [Expansion Section  55 ] 
     The expansion section  55  is disposed below the sheet stacking section  52  in the vertical direction V. Moreover, the expansion section  55  is movable in the horizontal direction H. Then, the expansion section  55  expands the surface for placing the sheets P in addition to the sheet stacking surface  52 P in a state of being pulled out from the sheet stacking section  52 . Then, in the state of being pulled out, the expansion section  55  makes it possible to place, for example, up to the A3-size sheet together with the sheet stacking section  52 . On the other hand, when not being used by the user, the expansion section  55  is contained under the sheet stacking section  52 . 
     [Sheet Guiding Section  70 ] 
     The sheet guiding section  70  includes: a first guiding section  71  that is provided on the front side in the front-back direction D and guides the sheets placed on the sheet stacking section  52 ; and a second guiding section  72  that is provided on the back side to be paired with the first guiding section  71  for guiding the sheets P. 
     The first guiding section  71  and the second guiding section  72  are movable in the front-back direction D in the sheet stacking section  52  by the operation of the user. The first guiding section  71  and the second guiding section  72  can be positioned at an arbitrary position in the front-back direction D. 
     Further, the first guiding section  71  and the second guiding section  72  move so that the moving amount when one of them is moved and the moving amount when the other one is moved are the same. Consequently, the sheet guiding section  70  is aligned so that the center portion of the sheet in the front-back direction D is aligned to a predetermined position in the sheet stacking section  52 . 
     Further, each of the first guiding section  71  and the second guiding section  72  includes a regulation section  70 R provided in accordance with the maximum sheet number stackable on the sheet stacking surface  52 P. The regulation section  70 R projects toward the inside of the sheet stacking surface  52 P. Moreover, when the sheets P of the maximum stacking number are stacked on the sheet stacking surface  52 P, the regulation section  70 R is provided at the height of the uppermost sheet P on the bundle of sheets of the maximum stacking number. The regulation section  70 R indicates the height (thickness) of the sheet bundle corresponding to the maximum stacking number to the user, and regulates the sheets not to be stacked exceeding the regulation section  70 R. 
     [Sheet Feeding Section  80 ] 
       FIG. 3  is an overall perspective view of the sheet feeding section  80  of the exemplary embodiment. 
       FIG. 4  is a plan view of the sheet feeding section  80  of the exemplary embodiment. 
       FIG. 5  is an illustration diagram of a regulation section  80 C of the exemplary embodiment. Note that  FIG. 5  shows a state in which a supporter  85  is positioned at a standby position, which will be described later. 
       FIG. 6  is an illustration diagram that illustrates a relationship among a feeding section  80 A, the regulation section  80 C and a second drive section  80 E of the exemplary embodiment. 
     As shown in  FIG. 3 , the sheet feeding section  80  includes: a feeding section  80 A (an example of a feeding unit) provided to be movable with respect to the sheet stacking surface  52 P to feed the sheets; and a suppressing section  80 B that suppresses multiple feeding of the sheets P when the sheets P are fed by the feeding section  80 A. Moreover, the sheet feeding section  80  includes a regulation section  80 C that regulates movement of the sheets P (the sheet bundle) stacked on the sheet stacking surface  52 P toward the downstream side in the sheet feeding direction. Further, the sheet feeding section  80  includes: a first drive section  80 D that drives pickup rolls  81  and feed rolls  82 , which will be described later; and a second drive section  80 E (an example of a moving unit) that drives a supporter  85 , which will be described later. 
     (Feeding Section  80 A) 
     As shown in  FIG. 4 , the feeding section  80 A includes: the pickup rolls  81  that are provided to be movable with respect to the sheet stacking surface  52 P (refer to  FIG. 3 ) to pick up the sheets P on the sheet stacking surface  52 P; and the feed rolls  82  that move in the same manner as the pickup rolls  81  to feed the sheets P picked up by the pickup rolls  81  toward the downstream side in the feeding direction. Further, the feeding section  80 A includes: a first shaft  83  to which the feed rolls  82  are attached; and a second shaft  84  to which the pickup rolls  81  are attached. 
     Further, the feeding section  80 A includes a first gear  831 , a gear group  832  and a second gear  833  that transfer rotation of the first shaft  83  to the second shaft  84 . Moreover, the feeding section  80 A includes: the supporter  85  through which the above-described first shaft  83  and second shaft  84  are passed; an arm  86  fastened to the supporter  85 ; and a tension spring  87  that provides a spring force (an example of an elastic force) to the supporter  85 . 
     Then, the feeding section  80 A includes: an unlock section  88  (an example of a releasing unit) that releases lock (limit on movement) on a stopper  93  by a stopper lock  94  to be described later; and a maintaining section  89  (an example of a maintaining unit) that maintains an unlocked state of the stopper  93  by the stopper lock  94 . 
     The pickup rolls  81  are fastened to the second shaft  84 . Moreover, in the exemplary embodiment, two pickup rolls  81  are provided in line in an axial direction of the second shaft  84 . Then, with the rotation of the second shaft  84 , the pickup rolls  81  are rotated in the same direction as the second shaft  84 . 
     The feed rolls  82  are fastened to the first shaft  83 . Moreover, in the exemplary embodiment, two feed rolls  82  are provided in line in the axial direction of the first shaft  83 . Then, with the rotation of the first shaft  83 , the feed rolls  82  are rotated in the same direction as the first shaft  83 . 
     Moreover, the feed rolls  82  are provided downstream of the pickup rolls  81  in the sheet feeding direction. The feed rolls  82  feed the sheet P while holding the sheet P with a retard roll  90  (refer to  FIG. 3 ), which will be described later. 
     The first shaft  83  is rotatably supported by the supporter  85  via a not-shown bearing. Moreover, the first shaft  83  is provided along the front-back direction D. Then, the first shaft  83  rotates, to thereby rotate the feed rolls  82  as described above. On the other hand, the first shaft  83  does not transfer the rotational force to the supporter  85 . In other words, the first shaft  83  slips in the supporter  85 . On the other hand, the first shaft  83  functions as a rotation shaft of the supporter  85 . 
     The second shaft  84  is rotatably supported by the supporter  85  via a not-shown bearing. The second shaft  84  is disposed upstream of the first shaft  83  in the sheet feeding direction. Moreover, the second shaft  84  is provided along the first shaft  83  with a predetermined interval. Then, the second shaft  84  rotates, to thereby rotate the pickup rolls  81  as described above. However, the second shaft  84  does not transfer the rotational force to the supporter  85 . 
     The first gear  831  is fastened to the first shaft  83 . Moreover, the first gear  831  is connected to the gear group  832 . The first gear  831  transfers the rotational force of the first shaft  83  to the gear group  832 . 
     The gear group  832  includes plural gear members. Then, the gear group  832  is connected to each of the first gear  831  and the second gear  833 . The gear group  832  transfers the rotational force of the first gear  831  to the second gear  833 . Moreover, the number of gears included in the gear group  832  is adjusted so that the rotation direction of the first gear  831  and the rotation direction of the second gear  833  are the same direction. In other words, the gear group  832  causes the first shaft  83  and the second shaft  84  to rotate in the same rotation direction. 
     The second gear  833  is fastened to the second shaft  84 . Moreover, the second gear  833  is connected to the gear group  832 . The second gear  833  transfers the rotational force of the gear group  832  to the second shaft  84 . 
     An outline of the supporter  85  is formed into a rectangular shape extending long in the front-back direction D. Then, in the exemplary embodiment, the supporter  85  is provided, inside thereof, with the first shaft  83 , the second shaft  84 , the first gear  831 , the gear group  832  and the second gear  833 . 
     Moreover, the supporter  85  is rotatable around the first shaft  83  as the rotation center. In the exemplary embodiment, the supporter  85  rotates, to thereby move the pickup rolls  81  forward or backward with respect to the sheet stacking surface  52 P (refer to  FIG. 3 ). 
     Then, as shown in  FIG. 3 , before the sheets are fed, the supporter  85  of the exemplary embodiment sometimes causes the pickup rolls  81  to be positioned at a standby position (sheet setting position), which is away from the sheet stacking surface  52 P by a predetermined distance for accepting setting of the sheets P on the sheet stacking surface  52 P by the user. 
     Moreover, immediately before the sheet feeding, the supporter  85  of the exemplary embodiment sometimes causes the pickup rolls  81  to be positioned at a releasing position (an unlock position) for releasing limitation on movement of the stopper  93 , which will be described later, of the regulation section  80 C. 
     Further, when the sheet feeding is to be performed, the supporter  85  of the exemplary embodiment sometimes causes the pickup rolls  81  to be positioned at the feeding position (sheet pickup position) where the pickup rolls  81  are brought into contact with the sheets P placed on the sheet stacking surface  52 P. 
     As shown in  FIG. 4 , the arm  86  is fastened to an end portion of the supporter  85  in the longitudinal direction. In the exemplary embodiment, the arm  86  is disposed on an opposite side of the side where the feed rolls  82  are provided. The arm  86  is formed to extend long in the horizontal direction H. Then, the arm  86  contacts a rotating cam  96 , which will be described later, of the second drive section  80 E. The arm  86  moves with the rotation of the rotating cam  96 , to thereby move the supporter  85 . 
     One end of the tension spring  87  is connected to the supporter  85 , and the other end thereof is connected to a stay  92 , which will be described later. Moreover, the tension spring  87  is connected to the supporter  85  on the downstream side of the first shaft  83  in the sheet feeding direction. Consequently, the tension spring  87  provides a force to the supporter  85  rotating around the first shaft  83  as the rotation center, the force rotating the second shaft  84  downward in the vertical direction V. In other words, the tension spring  87  always provides a force of a direction in which the pickup rolls  81  move toward the sheet stacking section  52  (refer to  FIG. 3 ) to the supporter  85 . 
     As shown in  FIG. 5 , the unlock section  88  is fastened to the supporter  85 . The unlock section  88  is provided to an end portion of the supporter  85  in the longitudinal direction, which is on the stopper lock  94  side, which will be described later, of the regulation section  80 C. The unlock section  88  of the exemplary embodiment projects in a columnar shape from the supporter  85  along the front-back direction D. Then, the unlock section  88  is disposed to contact the stopper lock  94  in accordance with the moving position of the supporter  85 . In the exemplary embodiment, the unlock section  88  is able to contact the stopper lock  94  when the supporter  85  is at the releasing position. 
     The maintaining section  89  is fastened to the supporter  85 . The maintaining section  89  is provided to an end portion of the supporter  85  in the longitudinal direction, which is on the stopper lock  94  side, which will be described later, of the regulation section  80 C. The maintaining section  89  of the exemplary embodiment projects in a columnar shape from the supporter  85  along the front-back direction D. Then, the maintaining section  89  is disposed to contact the stopper lock  94  in accordance with the moving position of the supporter  85 . In the exemplary embodiment, as will be described later, the maintaining section  89  is able to contact the stopper lock  94  when the supporter  85  is at the feeding position. 
     (Suppressing Section  80 B) 
     As shown in  FIG. 3 , the suppressing section  80 B includes: the retard roll  90  that rotates in a direction opposite to the rotation direction of the feed rolls  82 ; and a suppressing member  91  provided at a position facing the pickup rolls  81 . 
     The retard roll  90  is provided at a position facing the feed rolls  82 . The retard roll  90  rotates to forward the sheets P in a direction opposite to the sheet feeding direction by the feed rolls  82 . In other words, the retard roll  90  rotates in the direction opposite to the direction of rotation of the feed rolls  82 . Then, the retard roll  90  pinches the sheets P with the feed rolls  82 . For example, when the two sheets P are overlapped and sent between the retard roll  90  and the feed rolls  82  from the pickup rolls  81 , the retard roll  90  feeds back the sheet P that is not in contact with the feed rolls  82  to an opposite side of the sheet feeding direction. Consequently, only one sheet P is supplied by the feed rolls  82 . 
     The suppressing member  91  is provided at a position facing the pickup rolls  81 . The suppressing member  91  contacts, of the sheet bundle stacked on the sheet stacking surface  52 P, the sheet P that is closest to the sheet stacking surface  52 P. Then, when the uppermost sheet P of the sheet bundle is fed by the pickup rolls  81 , the suppressing member  91  causes the other sheets P to stay on the sheet stacking surface  52 P. 
     (Regulation Section  80 C) 
     Subsequently, the regulation section  80 C will be described in detail. 
     As shown in  FIG. 3 , when the sheets P are set on the sheet stacking section  52 , it is necessary to stem the sheets P on the downstream side in the sheet feeding direction of the sheet stacking section  52  to prevent the sheets P from entering the back side of the sheet feeding section  80 . Then, in the sheet feeding section  80  of the exemplary embodiment, movement of the sheets P toward the downstream side of the sheet feeding direction is regulated by the regulation section  80 C. On the other hand, when the sheets P placed on the sheet stacking section  52  are fed, it is necessary to release regulation on the movement of the sheets P by the regulation section  80 C. 
     As shown in  FIG. 5 , the regulation section  80 C includes: the stay  92  fastened to the main body housing section  60  (refer to  FIG. 1 ); the stopper  93  (an example of a contact unit) that contacts the sheets P stacked on the sheet stacking section  52  to regulate movement of the sheets P toward the downstream side in the feeding direction; and the stopper lock  94  (an example of a limitation unit) that limits movement of the stopper  93 . 
     The stay  92  is formed by a sheet metal. Then, the stay  92  is supported by the main body housing section  60 . Note that, even when the supporter  85  is moved by the second drive section  80 E, the stay  92  does not move. 
     As shown in  FIG. 6 , the stopper  93  is a member including a bending portion and extending in one direction. The stopper  93  is provided to be rotatable around a stopper shaft  93 S as a rotation center. In the exemplary embodiment, the stopper shaft  93 S is supported by the stay  92 . In other words, the stopper  93  is provided separately from the supporter  85 . 
     Moreover, the stopper  93  includes: a sheet regulation portion  931  with which the sheets P are brought into contact; and a receiving portion  932  that receives engagement of the stopper lock  94 . 
     Note that, in the exemplary embodiment, a center of gravity of the stopper  93  exists on the downstream side of the stopper shaft  93 S in the sheet feeding direction. Consequently, in a free state of not being in contact with the sheets P, the sheet regulation portion  931  side of the stopper  93  is going to rotate toward the downstream side in the sheet feeding direction by its own weight. 
     The sheet regulation portion  931  is formed to extend from the stopper shaft  93 S toward the sheet stacking surface  52 P. Then, in a state in which rotation of the stopper  93  is prevented by the stopper lock  94 , the sheet regulation portion  931  regulates movement of the sheets P stacked on the sheet stacking surface  52 P toward the downstream side of the stopper  93  in the sheet feeding direction. 
     The receiving portion  932  is formed to receive a latch portion  941 F, which will be described later, of the stopper lock  94 . Then, in the state where the stopper lock  94  is engaged, the receiving portion  932  limits the rotation of the stopper  93  around the stopper shaft  93 S. Even when the sheet regulation portion  931  of the stopper  93  is pressed by the sheet bundle, the receiving portion  932  stops the rotation of the stopper  93 . This makes the stopper  93  regulate the movement of the sheets P by the sheet regulation portion  931 . On the other hand, in the state where the stopper lock  94  is not engaged in the receiving portion  932 , the stopper  93  is able to rotate around the stopper shaft  93 S. Consequently, when the sheets P on the sheet stacking surface  52 P are fed, the stopper  93  is rotated by the contact of the sheets P, to thereby makes it possible to feed the sheets P. 
     The stopper lock  94  is a member extending long in one direction. Then, the stopper lock  94  is provided to be rotatable around a stopper lock shaft  94 S as a rotation center. In the exemplary embodiment, the stopper lock shaft  94 S is supported by the stay  92 . In other words, the stopper lock  94  is provided separately from the supporter  85 . 
     Moreover, the stopper lock  94  includes: a first arm portion  941  provided on one side with respect to the stopper lock shaft  94 S and a second arm portion  942  provided on the other side with respect to the stopper lock shaft  94 S. 
     The first arm portion  941  includes, on an end portion thereof, the latch portion  941 F (an example of a latch unit) to be engaged in the receiving portion  932  of the stopper  93 . Then, the latch portion  941 F is engaged in the receiving portion  932  of the stopper  93 , and thereby, the stopper lock  94  limits the rotation of the stopper  93 . 
     Then, the first arm portion  941  is positioned on the course of the unlock section  88  that moves with the supporter  85 . In particular, the first arm portion  941  is positioned on the course of the unlock section  88  when the supporter  85  is at the releasing position, to thereby contact the unlock section  88  at that time. Then, due to the contact of the unlock section  88  with the first arm portion  941  of the stopper lock  94 , the stopper lock  94  rotates in a direction in which the latch portion  941 F moves away from the receiving portion  932  of the stopper  93 . 
     The second arm portion  942  is positioned on the course of the maintaining section  89  that moves with the supporter  85 . In particular, the second arm portion  942  is positioned on the course of the maintaining section  89  when the supporter  85  is at the feeding position, to thereby contact the maintaining section  89  at that time. Then, due to the contact of the maintaining section  89  with the second arm portion  942  of the stopper lock  94 , the stopper lock  94  rotates in a direction in which the latch portion  941 F moves away from the receiving portion  932  of the stopper  93 , and the state is maintained. 
     Moreover, in the exemplary embodiment, the first arm portion  941  is longer than the second arm portion  942 . Consequently, in a free state of not being in contact with other members, the first arm portion  941  side of the stopper lock  94  is going to rotate in the downward direction by its own weight. 
     (First Drive Section  80 D) 
     As shown in  FIG. 4 , the first drive section  80 D includes: a drive gear  95  fastened to the first shaft  83 ; and a first motor  95 M that rotates the drive gear  95 . 
     The drive gear  95  is connected to a not-shown gear member driven by the first motor  95 M. The drive gear  95  transfers the power of the first motor  95 M to the first shaft  83 . 
     The first motor  95 M is controlled by a not-shown controller to be operated at a predetermined timing. Then, the first motor  95 M rotates the first shaft  83  via the drive gear  95 , to thereby rotate the feed rolls  82 . Further, the first motor  95 M rotates the second shaft  84  via the first shaft  83 , to thereby rotate the pickup rolls  81 . 
     (Second Drive Section  80 E) 
     The second drive section  80 E includes: a rotating cam  96  (an example of a rotating cam) connected to the arm  86 ; a cam shaft  96 S serving as the rotation shaft of the rotating cam  96 ; a second drive gear  97  fastened to the cam shaft  96 S; and a second motor  97 M that rotates the second drive gear  97 . 
     As shown in  FIG. 6 , the rotating cam  96  has a predetermined cam profile formed on an outer circumferential portion thereof, and rotates around the cam shaft  96 S as the rotation center. The rotating cam  96  moves the supporter  85  via the arm  86 . 
     The rotating cam  96  of the exemplary embodiment includes, as the cam profile in the circumferential direction of the rotating cam  96 : a first shape portion  961  that causes the supporter  85  to be positioned at the standby position; a second shape portion  962  that causes the supporter  85  to be positioned at the releasing position; and a third shape portion  963  that causes the supporter  85  to be positioned at the feeding position. Then, in the exemplary embodiment, the rotating cam  96  rotates in the predetermined direction, to be thereby brought into contact with the arm  86  by the first shape portion  961 , the second shape portion  962  and the third shape portion  963  in this order. 
     The first shape portion  961  is a region where the distance from the cam shaft  96 S is a first radius R 1 . 
     The second shape portion  962  is a region where the distance from the cam shaft  96 S is a second radius R 2 , which is longer than the first radius R 1 . Note that the second radius R 2  in the second shape portion  962  is the largest radius in the rotating cam  96  of the exemplary embodiment. 
     Further, the third shape portion  963  is a region where the distance from the cam shaft  96 S is a third radius R 3 , which is shorter than the first radius R 1 . The third radius R 3  in the third shape portion  963  is the shortest radius in the rotating cam  96  of the exemplary embodiment. Then, in the exemplary embodiment, with the third shape portion  963 , the contact by the arm  86  is released, to thereby set the arm  86  free. 
     Then, the rotating cam  96  of the exemplary embodiment varies smoothly from the first shape portion  961  to the second shape portion  962  and then the third shape portion  963 . Consequently, in the exemplary embodiment, when the portion of the rotating cam  96  that is in contact with the arm  86  is changed, a load due to the change is not applied to the second motor  97 M. 
     The cam shaft  96 S is rotatably supported by a not-shown member. To the cam shaft  96 S, the rotating cam  96  is fastened. The cam shaft  96 S becomes the rotation center of the rotating cam  96 . 
     The second drive gear  97  is connected to a not-shown gear member driven by the second motor  97 M. The second drive gear  97  transfers the power of the second motor  97 M to the cam shaft  96 S. 
     The second motor  97 M is controlled by a not-shown controller to be operated at a predetermined timing and a rotation amount. Then, the second motor  97 M rotates the cam shaft  96 S via the second drive gear  97 , to thereby rotate the rotating cam  96 . Note that, in the exemplary embodiment, the second motor  97 M rotates the rotating cam  96  in a predetermined direction. 
     Next, moving operations of the supporter  85  by the first drive section  80 D will be described in detail. 
       FIGS. 7A to 7D  are illustration diagrams of operations of the supporter  85  of the exemplary embodiment. 
     As described above, in the exemplary embodiment, the first drive section  80 D rotates the supporter  85  in accordance with the rotating angle of the rotating cam  96 . With the rotation, the supporter  85  moves the pickup rolls  81  forward or backward with respect to the sheet stacking surface  52 P. 
     As shown in  FIG. 7A , the rotating cam  96  brings the first shape portion  961  in contact with the arm  86 , to thereby set the supporter  85  at the standby position. In this state, the pickup rolls  81  supported by the supporter  85  are separated from the sheet stacking surface  52 P by a predetermined distance. The position of the pickup rolls  81  at this time corresponds to the height of the regulation section  70 R (refer to  FIG. 2 ). In other words, the rotating cam  96  brings the first shape portion  961  into contact with the arm  86 , to thereby causes the pickup rolls  81  at the position corresponding to the height of the uppermost sheet when the sheets of the maximum stacking number are set on the sheet stacking surface  52 P (full stack height). 
     As shown in  FIG. 7B , the rotating cam  96  brings the second shape portion  962  in contact with the arm  86 , to thereby set the supporter  85  at the releasing position. In this state, the pickup rolls  81  supported by the supporter  85  are at the position higher than the height of the uppermost sheet P when the sheets P of the maximum stacking number are set on the sheet stacking surface  52 P. 
     As shown in  FIG. 7C , the rotating cam  96  causes the third shape portion  963  to face the arm  86 , to thereby set the supporter  85  at the feeding position. Specifically, due to the third shape portion  963  of the rotating cam  96  facing the arm  86 , the arm  86  becomes incapable of reaching the rotating cam  96 . As a result, the arm  86  and the supporter  85  to which the arm  86  is connected become freely rotatable around the first shaft  83  as the rotation center. Here, to the supporter  85 , the tension spring  87  is connected. Consequently, a side of the supporter  85  opposite to the pickup rolls  81  in the horizontal direction H is pulled up by the tension spring  87 . As a result, the pickup rolls  81  supported by the supporter  85  are moved in a direction approaching the sheet stacking surface  52 P. Note that, in this state, the pickup rolls  81  are positioned at the height of the sheets P placed on the sheet stacking surface  52 P. 
     Then, as shown in  FIG. 7D , the rotating cam  96  is brought into contact with the arm  86  from the third shape portion  963  to the first shape portion  961 , and thereby the supporter  85  moves upward. Then, the supporter  85  returns to the standby position again. 
     Note that, as described above, as shown in  FIGS. 7A and 7B , in the exemplary embodiment, the supporter  85  (the pickup rolls  81 ) is moved in a direction away from the sheet stacking surface  52 P by the driving force of the second motor  97 M via the rotating cam  96 . On the other hand, as shown in  FIG. 7C , the supporter  85  (the pickup rolls  81 ) is moved in a direction approaching the sheet stacking surface  52 P by the spring force of the tension spring  87 . 
     Subsequently, with reference to  FIGS. 8 to 11 , the relationship between the supporter  85  and the regulation section  80 C will be described. 
       FIG. 8  is a relationship diagram of the supporter  85  and the regulation section  80 C at the releasing position. 
       FIG. 9  is a relationship diagram of the supporter  85  and the regulation section  80 C moving toward the releasing position. 
       FIG. 10  is a relationship diagram of the supporter  85  and the regulation section  80 C at the feeding position. 
       FIG. 11  is a relationship diagram of the supporter  85  and the regulation section  80 C moving toward the standby position. 
     As shown in  FIG. 6 , the supporter  85  at the standby position sets the pickup rolls  81  at a position separated from the sheet stacking surface  52 P by the predetermined distance. Consequently, on the sheet stacking surface  52 P, including the location under the pickup rolls  81 , the sheets P can be placed. At this time, the stopper  93  is positioned on the downstream side in the sheet feeding direction of the sheet stacking surface  52 P. Further, rotation of the stopper  93  is limited by the stopper lock  94 . Consequently, even though the sheets P are pressed toward the downstream side in the sheet feeding direction when the user sets the sheets P on the sheet stacking surface  52 P, the sheets P do not enter inside the sheet feeding section  80 . 
     Thereafter, for example, with the start of printing or the like by the user as an impetus, the rotating cam  96  is rotated. Then, the sheet feeding section  80 , first, moves the supporter  85  moves from the standby position to the releasing position. 
     As shown in  FIG. 8 , the supporter  85  at the releasing position sets the pickup rolls  81  at a position farther away than the standby position from the sheet stacking surface  52 P. At this time, the unlock section  88  provided to the supporter  85  is moved upward together with the supporter  85 . Then, with the movement, the unlock section  88  is brought into contact with the first arm portion  941  of the stopper lock  94 . This rotates the stopper lock  94  in a direction in which the latch portion  941 F of the stopper lock  94  moves away from the receiving portion  932  of the stopper  93 . As a result, the stopper lock  94  releases the limit on the rotation of the stopper  93 . 
     Thereafter, as shown in  FIG. 9 , the unlock section  88  does not contact the stopper lock  94 . Consequently, the stopper lock  94  is going to rotate in a direction in which the latch portion  941 F approaches the receiving portion  932 . On the other hand, since the load of the sheet bundle is applied to the sheet regulation portion  931 , the receiving portion  932  side of the stopper  93  is slightly rotated toward the upstream side in the sheet feeding direction. Accordingly, though not in contact with the unlock section  88 , the latch portion  941 F of the stopper lock  94  is not engaged in the receiving portion  932 . 
     Further, as shown in  FIG. 10 , the sheet feeding section  80  further rotates the rotating cam  96 , to thereby move the supporter  85  from the releasing position to the feeding position. In other words, the pickup rolls  81  are moved in a direction approaching the sheet stacking surface  52 P (the sheets P). At this time, the sheets P are placed on the sheet stacking surface  52 P. Therefore, the pickup rolls  81  are stopped at the position to contact the uppermost sheet P of the sheet bundle. 
     Moreover, since the supporter  85  moves in the direction approaching the sheet stacking surface  52 P, the maintaining section  89  fastened to the supporter  85  moves downward together with the supporter  85 . Then, with the movement, the maintaining section  89  is brought into contact with the second arm portion  942  of the stopper lock  94 . This rotates the stopper lock  94  in a direction in which the latch portion  941 F moves away from the receiving portion  932 . Consequently, the state of releasing the regulation of the stopper  93  by the stopper lock  94  is maintained. After the limit on the movement of the stopper  93  by the stopper lock  94  is released, the state is continued, at least, for a period in which the supporter  85  moves in the direction approaching the sheet stacking section  52 . 
     Then, in the exemplary embodiment, the sheets P are sequentially fed from the sheet bundle on the sheet stacking surface  52 P by the pickup rolls  81 . 
     Thereafter, when all of the sheets P on the sheet stacking surface  52 P are fed, the rotating cam  96  is rotated to move the supporter  85  in the direction away from the sheet stacking surface  52 P. Note that sensing of presence or absence of the sheets P on the sheet stacking surface  52 P is performed by the sensor  98  (refer to  FIG. 2 ). 
     Then, as shown in  FIG. 11 , when there is no sheet P on the sheet stacking surface  52 P, the sheet regulation portion  931  of the stopper  93  moves toward the upstream side in the sheet feeding direction. In other words, the stopper  93  is going to move in a direction in which the receiving portion  932  approaches the stopper lock  94 . Moreover, the supporter  85  moves in the direction away from the sheet stacking surface  52 P, to thereby rotate the stopper lock  94  in a direction in which the latch portion  941 F approaches the receiving portion  932 . This disposes the stopper  93  and the stopper lock  94  in a positional relationship that enables the latch portion  941 F and the receiving portion  932  to be engaged in each other again. 
     In the sheet feeding section  80  of the exemplary embodiment configured as described above, limitation on rotation of the stopper  93  by the stopper lock  94  is released by the unlock section  88  fastened to the supporter  85  driven by the second motor  97 M. Accordingly, for example, even in the case where a large load is applied on the stopper  93  and the stopper lock  94  and the stopper  93  are strongly engaged with each other, such as when a large number of sheets P are placed on the sheet stacking surface  52 P, the engagement is released by use of the driving force of the second motor  97 M. 
     Moreover, in the sheet feeding section  80  in the exemplary embodiment, the supporter  85  is moved by the spring force of the tension spring  87  to set the supporter  85  at the feeding position. Therefore, in the sheet feeding section  80  of the exemplary embodiment, the pickup rolls  81  contact the sheets P with a constant force regardless of conditions. 
     [Image Forming Apparatus  1  in Modified Example] 
       FIGS. 12A to 12C  are illustration diagrams of the sheet feeding section  80  in a modified example. 
     Next, the image forming apparatus  1  of a modified example will be described. Note that, in the description of the modified example, configurations similar to those in the above-described exemplary embodiment are assigned with same reference signs, and detailed descriptions thereof will be omitted. 
     The image forming apparatus  1  in the modified example is different from the above-described exemplary embodiment in a configuration of a second drive section  280 E of the sheet feeding section  80 . Hereinafter, the second drive section  280 E of the modified example will be described in detail. 
     As shown in  FIG. 12A , the second drive section  280 E of the modified example includes: a third gear  835  that transfers power to the supporter  85 ; a fourth gear  836  connected to the third gear  835 ; and the second motor  97 M that rotates the fourth gear  836 . 
     The third gear  835  is rotatably supported by the first shaft  83 . In other words, the third gear  835  spins around the first shaft  83 . The third gear  835  is connected to the supporter  85 . The third gear  835  is also connected to the fourth gear  836 . 
     The fourth gear  836  is driven by the second motor  97 M and transfers the rotational force to the third gear  835 . Further, the fourth gear  836  includes: a teeth portion  836 P in which teeth engaged with the third gear  835  in the circumferential direction are formed; and a flat portion  836 N on which no teeth are formed. In other words, the fourth gear  836  is a missing teeth gear. 
     In the sheet feeding section  80  of the modified example, the second drive section  280 E rotates the fourth gear  836 , to thereby moves the supporter  85  to the standby position, the releasing position and the feeding position. 
     As shown in  FIG. 12B , when the supporter  85  is moved from the standby position to the releasing position, the fourth gear  836  is rotated by the second motor  97 M. At this time, the teeth portion  836 P of the fourth gear  836  is engaged with the third gear  835 . This rotates the third gear  835 , and thereby the supporter  85  is rotated upwardly around the first shaft  83  as the rotation shaft. With the movement of the supporter  85 , the unlock section  88  releases limitation on the rotation of the stopper  93  by the stopper lock  94  (refer to  FIG. 8 ). 
     Further, as shown in  FIG. 12C , when the supporter  85  is moved from the releasing position to the feeding position, the fourth gear  836  is further rotated by the second motor  97 M. Therefore, the flat portion  836 N of the fourth gear  836  faces the third gear  835 . This releases the engagement between the third gear  835  and the fourth gear  836 . As a result, the supporter  85  is rotated in a direction in which the pickup rolls  81  approach the sheet stacking surface  52 P by the spring force of the tension spring  87 . 
     Thereafter, when the sheets P of the sheet bundle on the sheet stacking surface  52 P are sequentially fed, the fourth gear  836  is rotated by the second motor  97 M. Then, by engaging the teeth portion  836 P of the fourth gear  836  with the third gear  835 , the supporter  85  is rotated to return to the standby position again. 
     Note that, in the description of the exemplary embodiment, the example applying the above-described sheet guiding section  70  in the second sheet supply section  50  is taken; however, the sheet guiding section  70  is not limited to be applied to the second sheet supply section  50 . The sheet guiding section  70  may be applied to, for example, the stacking section  21 S of the original feeding device  21 . Further, the sheet guiding section  70  may be applied to the first sheet supply section  40 . 
     The foregoing description of the present exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The present exemplary embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.