Patent Publication Number: US-2015063888-A1

Title: Sheet conveying apparatus, and image forming apparatus including sheet conveying apparatus

Description:
The application is based on Japanese Patent Application No. 2013-176603 filed with the Japan Patent Office on Aug. 28, 2013, the contents of which are incorporated herein by reference. 
     BACKGROUND 
     The disclosure relates to a sheet conveying apparatus that conveys sheets and an image forming apparatus including the sheet conveying apparatus. 
     Image forming apparatuses that form images on sheets conventionally include a sheet conveying apparatus that conveys sheets. A sheet with an image formed on a surface of the sheet using an electrophotographic technique is discharged into a sheet discharging section provided in the apparatus main body of the image forming apparatus. 
     A technique is known which uses a first conveying path and a second conveying path arranged as conveying paths along which sheets with images formed thereon are conveyed to a sheet discharging section. 
     According to this technique, the first conveying path and the second conveying path each include a conveying roller arranged on the conveying path to convey sheets. Regardless of which of the conveying paths is used to convey sheets, both of the conveying rollers is rotated. 
     SUMMARY 
     A sheet conveying apparatus according to an aspect of the disclosure includes a first conveying path, a second conveying path and a third conveying path, a switching guide, a conveying roller, a roller shaft, a driving mechanism, a transmission mechanism, and an position change mechanism. A sheet is conveyed along the first conveying path in a predetermined conveying direction. The second conveying path and the third conveying path are formed on a downstream side of the first conveying path in the conveying direction by diverging from the first conveying path so that the sheet is selectively conveyed along the second conveying path or along the third conveying path. The switching guide is arranged to extend in a sheet width direction crossing the conveying direction and switches the conveying path, to which the sheet conveyed from the first conveying path, between the second conveying path and the third conveying path. The switching guide enables an position thereof to be changed between a first position in which the sheet is conveyed into the second conveying path and a second position in which the sheet is conveyed into the third conveying path. The conveying roller is arranged on the third conveying path to convey the sheet conveyed from the first conveying path. The roller shaft is arranged to extend in the sheet width direction and axially supports the conveying roller rotatably. The driving mechanism generates a rotational driving force that rotates the conveying roller. The transmission mechanism disconnects transmission of the rotational driving force to the conveying roller in the first position of the switching guide and transmits the rotational driving force to the conveying roller in the second position of the switching guide. The position change mechanism changes the position of the switching guide between the first position and the second position. 
     Furthermore, an image forming apparatus according to another aspect of the disclosure includes an apparatus main body, an image forming section, and the sheet conveying apparatus. The image forming section is arranged in the apparatus main body to form a toner image on a sheet. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing the appearance of an image forming apparatus according to an embodiment of the disclosure; 
         FIG. 2  is a cross-sectional view schematically showing the internal structure of the image forming apparatus according to the embodiment of the disclosure; 
         FIG. 3  is a cross-sectional view of the periphery of a sheet conveying apparatus in the image forming apparatus according to the embodiment of the disclosure; 
         FIG. 4  is a cross-sectional view of the periphery of the sheet conveying apparatus in the image forming apparatus according to the embodiment of the disclosure; 
         FIG. 5  is an exploded perspective view of the sheet conveying apparatus according to the embodiment of the disclosure; 
         FIG. 6  is an exploded perspective view of the sheet conveying apparatus according to the embodiment of the disclosure; 
         FIG. 7  is a perspective view of a part of the sheet conveying apparatus according to the embodiment of the disclosure; 
         FIG. 8  is a perspective view of a part of the sheet conveying apparatus according to the embodiment of the disclosure; 
         FIG. 9  is a perspective view of the periphery of the sheet conveying apparatus in the image forming apparatus according to the embodiment of the disclosure; 
         FIG. 10  is a cross-sectional view of the periphery of a driving mechanism of the sheet conveying apparatus according to the embodiment of the disclosure; 
         FIG. 11  is a cross-sectional view of the periphery of the driving mechanism of the sheet conveying apparatus according to the embodiment of the disclosure; 
         FIG. 12  is a perspective view of the periphery of a switching guide of the sheet conveying apparatus according to the embodiment of the disclosure; 
         FIG. 13  is a perspective view of the periphery of the switching guide of the sheet conveying apparatus according to the embodiment of the disclosure; 
         FIG. 14  is an enlarged perspective view of the periphery of an position change mechanism of the sheet conveying apparatus according to the embodiment of the disclosure; and 
         FIG. 15  is an enlarged perspective view of the periphery of the position change mechanism of the sheet conveying apparatus according to the embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the drawings, an embodiment of the disclosure will be described below.  FIG. 1  is a perspective view of a printer  100  (image forming apparatus) according to an embodiment of the disclosure.  FIG. 2  is a cross-sectional view schematically showing the internal structure of the printer  100 . The printer  100  shown in  FIG. 1  and  FIG. 2  is what is called a monochrome printer machine. However, in other embodiments, the image forming apparatus may be a color printer, a facsimile apparatus, a multifunction printer having the functions of a color printer and a facsimile apparatus, or another other apparatus that forms a toner image on a sheet. Terms such as “upper” and “lower”, “front” and “rear”, and “left” and “right” as used herein are simply intended for clear description and not for limitation of the principle of the image forming apparatus. 
     The printer  100  includes a housing  200  (apparatus main body) that houses various apparatuses for forming an image on a sheet S. The housing  200  includes an upper wall  201  that defines an upper surface of the housing  200 , a bottom wall  220  ( FIG. 2 ) that defines a bottom surface of the housing  200 , a rear wall  245  ( FIG. 2 ) between the upper wall  201  and the bottom wall  220 , and a front wall  250  positioned in front of the rear wall  245 . The housing  200  includes a main body internal space  260  (internal space) in which various apparatuses are arranged. 
     A sheet discharge section  210  (upper surface sheet discharge section) is arranged in a central portion of the upper wall  201 . The sheet discharge section  210  includes an inclined surface that is inclined downward from a front portion toward a rear portion of the upper wall  201 . The sheet S with an image formed thereon by an image forming section  120  described below is discharged into the sheet discharge section  210 . Furthermore, a manual tray  240  is arranged in a central portion of the front wall  250  in an up-down direction. 
     The manual tray  240  is rotationally movable in the up-down direction (arrow D 1  in  FIG. 2 ) using a lower end of the manual tray  240  as a pivot. 
     The printer  100  includes a cassette  110 , a pickup roller  112 , a first sheet feeding roller  113 , a second sheet feeding roller  114 , a conveying roller  115 , a registration roller pair  116 , and the image forming section  120 . 
     The cassette  110  internally houses sheets S. The cassette  110  includes a lift plate  111  supports the sheets S. The lift plate  111  is inclined so as to push leading edges of the sheets S up. The cassette  110  defines a part of the front wall  250  of the housing  200  and can be withdrawn forward with respect to the housing  200 . 
     The pickup roller  112  is arranged above the leading edges of the sheets S pushed up by the lift plate  111 . Rotation of the pickup roller  112  allows the sheet S to be conveyed from the cassette  110 . 
     The first sheet feeding roller  113  is disposed on a downstream side of the pickup roller  112 . The first sheet feeding roller  113  feeds the sheet S further downstream. The second sheet feeding roller  114  is disposed inside (behind) a pivot of the manual tray  240 . The second sheet feeding roller  114  draws the sheet S on the manual tray  240  into the housing  200 . A user can selectively use the sheet S housed in the cassette  110  or the sheet S placed on the manual tray  240 . 
     The conveying roller  115  is disposed on a downstream side of the first sheet feeding roller  113  and the second sheet feeding roller  114  in a sheet conveying direction (hereinafter also simply referred to as a conveying direction) (“downstream in the sheet conveying direction” is hereinafter also simply referred to as “downstream”). The conveying roller  115  conveys the sheet S fed out by the first sheet feeding roller  113  and the second sheet feeding roller  114 , further downstream. 
     The registration roller pair  116  has a function to correct diagonal conveyance of the sheet S. This allows an image formed on the sheet S to be aligned. The registration roller pair  116  feeds the sheet S to the image forming section  120  in a timely manner when the image forming section  120  forms an image. 
     The image forming section  120  is arranged in the housing  200  to form a toner image on the sheet S. The image forming section  120  includes a photosensitive drum  121  (image bearer), a charger  122 , an exposure apparatus  123 , a developing apparatus  124 , a toner container  125 , a transfer roller  126  (transfer section), and a cleaning apparatus  127 . 
     The photosensitive drum  121  is shaped like a cylinder. An electrostatic latent image is formed on a circumferential surface of the photosensitive drum  121 , and the photosensitive drum  121  bears a toner image associated with the electrostatic latent image. A predetermined voltage is applied to the charger  122  to substantially uniformly charge a circumferential surface of the photosensitive drum  121 . 
     The exposure apparatus  123  delivers laser light to the circumferential surface of the photosensitive drum  121  charged by the charger  122 . The laser light is delivered in accordance with image data output by an external apparatus such as a personal computer (not shown in the drawings) which is connected to the printer  100  for communication with the printer  100 . As a result, an electrostatic latent image corresponding to the image data is formed on the circumferential surface of the photosensitive drum  121 . 
     The developing apparatus  124  supplies toner to the circumferential surface of the photosensitive drum  121  with the electrostatic latent image formed thereon. The toner container  125  supplies toner to the developing apparatus  124 . When the developing apparatus  124  supplies the toner to the photosensitive drum  121 , the electrostatic latent image formed on the circumferential surface of the photosensitive drum  121  is developed (visualized). As a result, a toner image is formed on the circumferential surface of the photosensitive drum  121 . 
     The transfer roller  126  is rotatably disposed in abutting contact with the circumferential surface of the photosensitive drum  121 . When the sheet S conveyed from the registration roller pair  116  passes between the photosensitive drum  121  and the transfer roller  126 , the toner image formed on the circumferential surface of the photosensitive drum  121  is transferred to the sheet S. The transfer roller  126  is arranged opposite the exposure apparatus  123  as viewed from the photosensitive drum  121 . 
     The cleaning apparatus  127  removes toner remaining on the circumferential surface of the photosensitive drum  121  after the toner image is transferred to the sheet S. 
     The printer  100  further includes a fixing apparatus  130  (fixing section) arranged on a downstream side of the image forming section  120  in the conveying direction to execute a process of fixing the toner image on the sheet S. The fixing apparatus  130  includes a heating roller  131  (roller member) that melts the toner on the sheet S and a pressure roller  132  that brings the sheet S into tight contact with the heating roller  131 . When the sheet S passes between the heating roller  131  and the pressure roller  132 , the toner image is fixed to the sheet S. The heating roller  131  is rotationally driven by a driving mechanism  6  described below. The pressure roller  132  is rotated in conjunction with the heating roller  131 . 
     The printer  100  further includes a conveying roller pair  133  disposed on a downstream side of the fixing apparatus  130  and a discharge roller pair  134  disposed on a downstream side of the conveying roller pair  133 . The sheet S is conveyed upward by the conveying roller pair  133  and finally discharged from the housing  200  by the discharge roller pair  134 . The sheet S discharged from the housing  200  is stacked on the sheet discharge section  210 . 
     Moreover, the printer  100  includes a sheet conveying section  3  (sheet conveying apparatus). Now, with reference to  FIG. 3  and  FIG. 4  in addition to  FIG. 2 , the sheet conveying section  3  will be described.  FIG. 3  and  FIG. 4  are cross-sectional views of the sheet conveying section  3  of the printer  100  according to the present embodiment.  FIG. 3  is a cross-sectional view showing that the sheet guide  30  described below is in a first position where the sheet S is discharged into the sheet discharge section  210 . On the other hand,  FIG. 4  is a cross-sectional view showing that the sheet guide  30  is in a second position where the sheet S is discharged by a discharge roller  31  described below and arranged on the rear wall  245  side. 
     As shown in  FIG. 3  and  FIG. 4 , the sheet conveying section  3  conveys the sheet S on which the fixing process has been executed by the fixing apparatus  130 . The sheet conveying section  3  includes a first conveying path SP 1 , a second conveying path SP 2 , and a third conveying path SP 3 . As shown in  FIG. 1  and  FIG. 3 , the first conveying path SP 1  extends so as to pass through the fixing apparatus  130  so that the sheet S is conveyed rearward (in a predetermined conveying direction). The second conveying path SP 2  and the third conveying path SP 3  are conveying paths formed on a downstream side of the first conveying path SP 1  in the conveying direction by diverging from the first conveying path SP 1  so that the sheet S is selectively conveyed along the second conveying path SP 2  or along the third conveying path SP 3 . The second conveying path SP 2  extends in a vertical direction along a rear wall  245 . The second conveying path SP 2  extends through the conveying roller pair  133  to the upper discharge roller pair  134 . That is, the sheet S is discharged into the sheet discharge section  210  via the second conveying path SP 2 . On the other hand, the third conveying path SP 3  is a conveying path extending from the first conveying path SP 1  toward the rear wall  245 . The sheet S conveyed into the third conveying path SP 3  is discharged to the outside of the rear wall  245  via a slit-like discharge opening  245 S ( FIG. 3 ) (side discharge section) formed in the rear wall  245 . A sheet discharge tray (not shown in the drawings) installed at the discharge opening  245 S allows the sheet S to be discharged into the sheet discharge tray via the third conveying path SP 3 . Any post-processing apparatus or the like may be connected to the discharge opening  245 S. 
     The sheet conveying section  3  includes a sheet guide  30  (switching guide), a discharge roller  31  (conveying roller), a driven roller  32 , and an intermediate conveying roller pair  33 . 
     The sheet guide  30  switches the conveying path along which the sheet S from the first conveying path SP 1  is conveyed, between the second conveying path SP 2  and the third conveying path SP 3 . The sheet guide  30  allows the position thereof to be changed between a first position in which the sheet S is conveyed into the second conveying path SP 2  and a second position in which the sheet S is conveyed into the third conveying path SP 3 . As described above,  FIG. 3  shows that the sheet guide  30  is placed in the first position, and  FIG. 4  shows that the sheet guide  30  is placed in the second position. A control section (not shown in the drawings) arranged in the printer  100  changes the position of the sheet guide  30  in accordance with a destination to which the sheet S is discharged. 
     The discharge roller  31  is arranged on the third conveying path SP 3  to convey the sheet S conveyed from the first conveying path SP 1  toward the discharge opening  245 S. The discharge roller  31  is rotatably supported by a guide unit  40  described below. Furthermore, the discharge roller  31  is rotationally driven by a driving mechanism  6  described below. The driven roller  32  is arranged above and opposite the discharge roller  31 . The driven roller  32  is rotatably supported by a frame (not shown in the drawings) in the housing  200 . The driven roller  32  rotates in conjunction with the discharge roller  31 . The sheet S is conveyed while passing between the discharge roller  31  and the driven roller  32 . The intermediate conveying roller pair  33  is arranged on a downstream side of the fixing apparatus  130  in the conveying direction. The intermediate conveying roller pair  33  conveys the sheet S toward the sheet guide  30 . The sheet S conveyed by the intermediate conveying roller pair  33  is guided by the sheet guide  30  and conveyed into the second conveying path SP 2  or into the third conveying path SP 3 . 
     Thus, in the present embodiment, the sheet S from the first conveying path SP 1  is selectively conveyed into the second conveying path SP 2  or into the third conveying path SP 3 . The discharge roller  31  is arranged on the third conveying path SP 3 . In other words, when the sheet S is conveyed into the second conveying path SP 2 , the discharge roller  31  need not be rotated. Conventionally, for example, when the sheet S are consecutively conveyed into the second conveying path SP 2 , unwanted rotation of the discharge roller  31  may facilitate wear of the discharge roller  31  and the driven roller  32  in conjunction with the rotation. Furthermore, conventionally, unwanted rotation sound may disadvantageously be generated in conjunction with the rotation of the discharge roller  31 . 
     According to the present embodiment, to solve such problems, the sheet conveying section  3  rotationally drives the discharge roller  31  in accordance with the destination into which the sheet S is conveyed. Now, with reference to  FIG. 5  to  FIG. 15 , the structure and functions of the sheet conveying section  3  will be described below in further detail.  FIG. 5  and  FIG. 6  are exploded perspective views of the sheet conveying section  3  according to the present embodiment.  FIG. 7  and  FIG. 8  are perspective views of the sheet guide  30  and a guide unit  40  in the sheet conveying section  3  according to the present embodiment.  FIG. 8  corresponds to  FIG. 7  in which a support frame  53  described below has been removed.  FIG. 9  is a perspective view of the periphery of the driving mechanism  6  of the sheet conveying section  3 .  FIG. 10  and  FIG. 11  are cross-sectional views of the periphery of a driving transmission mechanism of the sheet conveying section  3 .  FIG. 10  corresponds to a case where the sheet guide  30  is placed in the first position.  FIG. 11  corresponds to a case where the sheet guide  30  is placed in the second position.  FIG. 12  and  FIG. 13  are perspective views of the periphery of the sheet guide  30  of the sheet conveying section  3 .  FIG. 12  corresponds to the case where the sheet guide  30  is placed in the first position.  FIG. 13  corresponds to the case where the sheet guide  30  is placed in the second position.  FIG. 14  and  FIG. 15  are enlarged perspective view of the periphery of a moving mechanism  7  of the sheet guide  30 .  FIG. 14  corresponds to the case where the sheet guide  30  is placed in the first position.  FIG. 15  corresponds to the case where the sheet guide  30  is placed in the second position. 
     As shown in  FIG. 5  and  FIG. 6 , the sheet conveying section  3  includes, in addition to the sheet guide  30  and the discharge roller  31 , the guide unit  40 , a roller shaft  31 A, and a transmission mechanism  5 . 
     The sheet guide  30  is a member extending in a sheet width direction (lateral direction) crossing the sheet conveying direction and is shaped generally like a triangle in section as viewed in a front-rear direction and in the up-down direction. The sheet guide  30  includes a guide main body  300 , a first support shaft  303  and a second support shaft  304  (guide shaft section), and an engaging shaft section  305 . 
     The guide main body  300  extends along an axial direction (sheet width direction) of the roller shaft  31 A described below. The guide main body  300  is a main body section of the sheet guide  30 . The guide main body  300  includes a first guide surface  301  and a second guide surface  302 . 
     The first guide surface  301  corresponds to one of the surfaces of the guide main body  300  extending in the sheet width direction. When the sheet guide  30  is in the first position, the sheet S conveyed from the intermediate conveying roller pair  33  is conveyed into the second conveying path SP 2  in abutting contact with the first guide surface  301 . The first guide surface  301  includes a plurality of ribs formed thereon and arranged at intervals in the lateral direction as shown in  FIG. 5 . 
     The second guide surface  302  corresponds to the other of the surfaces of the guide main body  300  extending in the sheet width direction. That is, the second guide surface  302  is arranged on a back surface of the first guide surface  301 . When the sheet guide  30  is in the second position, the sheet S conveyed from the intermediate conveying roller pair  33  is conveyed into the third conveying path SP 3  in abutting contact with the second guide surface  302 . The second guide surface  302  is leading end portions of the plurality of ribs arranged at intervals in the lateral direction as shown in  FIG. 5  and  FIG. 6 . The leading end portions of the plurality of ribs are curved so as to guide the sheet S toward the discharge roller  31 . 
     The first support shaft  303  and the second support shaft  304  are arranged on a right sidewall and a left sidewall, respectively, of the guide main body  300 . The first support shaft  303  and the second support shaft  304  are each arranged in a portion of the corresponding sidewall of the guide main body  300  which is located on a downstream side in the conveying direction for the sheet S. The first support shaft  303  and the second support shaft  304  are shaft sections extending from the guide main body  300  in the sheet width direction. The first support shaft  303  projects rightward from the right sidewall of the guide main body  300 . The second support shaft  304  projects leftward from the left sidewall of the guide main body  300 . The first support shaft  303  is inserted through a first bearing hole  402 A in the guide unit  40  described below. The second support shaft  304  is inserted through a second bearing hole  403 A in the guide unit  40 . The guide main body  300  moves rotationally around the first support shaft  303  and the second support shaft  304  to allow the sheet guide  30  to change the position thereof between the first position and the second position. 
     The engaging shaft section  305  is a projecting portion arranged on the left sidewall of the guide main body  300  below the second support shaft  304 . The engaging shaft section  305  projects leftward from the sidewall and includes a groove (not shown in the drawings) at a leading end portion of the engaging shaft section  305 . One end of a link  71  of the moving mechanism  7  described below is engaged with the groove in the engaging shaft section  305 . 
     The guide unit  40  is a unit arranged inside the housing  200  below the sheet guide  30 . The guide unit  40  is arranged on an upstream side of the sheet guide  30  in the conveying direction for the sheet S, to guide the sheet S. The guide unit  40  supports the sheet guide  30  so that the sheet guide  30  is rotationally movable. 
     The guide unit  40  supports the discharge roller  31  so that the discharge roller is rotationally movable. Furthermore, the guide unit  40  includes a unit guide section  401 , a first support wall  402 , and a second support wall  403 . 
     The unit guide section  401  is the main body section of the guide unit  40 . The unit guide section  401  has a function to guide the sheet S to the third conveying path SP 3 . As shown in  FIG. 5 , the unit guide section  401  includes a plurality of ribs arranged thereon at intervals in the lateral direction. Furthermore, the unit guide section  401  includes a pair of cutout portions  401 A formed at an upper edge of the unit guide section  401 . A pair of discharge rollers  31  is exposed from the cutout portions  401 A. The sheet S is conveyed into the third conveying path SP 3  while passing between the second guide surface  302  of the sheet guide  30  and the unit guide section  401 . Furthermore, as shown in  FIG. 2 , when the sheet S conveyed to the upper discharge roller pair  134  is conveyed in the opposite direction and conveyed into an opposite conveying path SP 4  ( FIG. 2 ), the unit guide section  401  guides the sheet S. The sheet S reaches the image forming section  120  again after being conveyed into the opposite conveying path SP 4  so that a toner image formed on a back surface of the sheet S. 
     The first support wall  402  is a sidewall portion arranged on the right side of the unit guide section  401 . The first support wall  402  stands so as to face rightward. The first support wall  402  includes a first bearing hole  402 A and a shaft insertion hole  402 B. The first bearing hole  402 A is a hole portion formed at an upper, rear end portion of the first support wall  402  so as to penetrate the first support wall  402  in the lateral direction. The first support shaft  303  is inserted through the first bearing hole  402 A. The shaft insertion hole  402 B is a hole portion formed below the first bearing hole  402 A so as to penetrate the first support wall  402  in the lateral direction. A roller shaft  31 A described below is inserted through the shaft insertion hole  402 B. 
     The second support wall  403  is a sidewall portion arranged on the left side of the unit guide section  401 . The second support wall  403  is a wall portion shaped like the character L as viewed in plan and stands so as to face forward and leftward. As shown in  FIG. 6 , the second support wall  403  includes a second bearing hole  403 A, a second roller bearing section  403 B, and a second bearing piece  403 C. The second bearing hole  403 A is a hole portion formed at an upper, rear end portion of the second support wall  403  so as to penetrate the second support wall  403  in the lateral direction. The second support shaft  304  is inserted through the second bearing hole  403 A. The second roller bearing section  403 B is a C-shaped bearing section arranged near the boundary between the unit guide section  401  and the second support wall  403 . The second bearing piece  403 C is a bearing fitted into the second roller bearing section  403 B. The second bearing piece  403 C supports the roller shaft  31 A so that the roller shaft  31 A is rotatable. 
     The roller shaft  31 A is arranged to extend in the sheet width direction, which crosses the conveying direction for the sheet S, and axially supports the pair of discharge rollers  31  so that the discharge rollers  31  are rotatable. A left end portion of the roller shaft  31 A is rotatably supported by the second bearing piece  403 C as described above. On the other hand, a right end portion of the roller shaft  31 A is rotatably supported by a first bearing piece  50 D fitted in a hole portion  50 C described below. 
     The transmission mechanism  5  is arranged opposite a right side (the other end side of the guide main body  300  in the sheet width direction) of the guide main body  300  of the sheet guide  30 . A part of the transmission mechanism  5  is installed on a first support wall  402  of the guide unit  40 . The transmission mechanism  5  disconnects transmission, to the discharge roller  31 , of a rotational driving force generated by the driving mechanism  6  described below, in association with the first position of the sheet guide  30 . Furthermore, the transmission mechanism  5  transmits the rotational driving force to the discharge roller  31  in association with the second position of the sheet guide  30 . In other words, the transmission mechanism  5  couples a transmission gear section  51  and the driving mechanism  6  together in conjunction with a change in the position of the sheet guide  30  from the first position to the second position which change is made by the moving mechanism  7  described below. Furthermore, the transmission mechanism  5  cancels (uncouples) the coupling between the transmission gear section  51  and the driving mechanism  6  in conjunction with a change in the position of the sheet guide  30  from the second position to the first position which change is made by the moving mechanism  7 . 
     The transmission mechanism  5  includes a discharge roller gear  52  (roller input gear), a rotational moving gear unit  5 A, the support frame  53 , and a bias spring  54 . 
     The rotational moving gear unit  5 A is rotationally movable between the first support wall  402  and the support frame  53 . The rotational moving gear unit  5 A moves rotationally using the roller shaft  31 A as a pivot. The rotational moving gear unit  5 A includes a gear plate  50  (gear mounting plate) and the transmission gear section  51 . 
     The gear plate  50  is the main body section of the rotational moving gear unit  5 A and is a plate-like member arranged between the first support wall  402  and the support frame  53 . The gear plate  50  is provided at one end side of the roller shaft  31 A. The gear plate  50  supports the transmission gear section  51  so that the transmission gear section  51  is rotatable, and can swing around the roller shaft  31 A with respect to the support frame  53  described below. The gear plate  50  includes a first gear shaft  50 A, a second gear shaft  50 B, a hole portion  50 C, a first bearing piece  50 D, and a pressed portion  50 E. 
     The first gear shaft  50 A projects rightward from a front portion of the gear plate  50 . The first gear shaft  50 A is shaped like a cylinder. A first transmission gear  51 A is axially supported by the first gear shaft  50 A so as to be rotatable. 
     The second gear shaft  50 B projects rightward from a rear, upper portion of the gear plate  50 . The second gear shaft  50 B is shaped like a cylinder. A second transmission gear  51 B is axially supported by the second gear shaft  50 B so as to be rotatable. 
     The hole portion  50 C is a hole portion formed in the gear plate  50  below the second gear shaft  50 B so as to penetrate the gear plate  50  in the lateral direction. The first bearing piece  50 D is a bearing fitted into the hole portion  50 C. After penetrating the shaft insertion hole  402 B ( FIG. 5 ), the roller shaft  31 A is inserted through the first bearing piece  50 D. Moreover, the right leading end portion of the roller shaft  31 A penetrates the first bearing piece  50 D and is inserted through the discharge roller gear  52  described below. 
     The pressed portion  50 E is a rectangular projecting piece projecting leftward from a rear edge of the gear plate  50 . The pressed portion  50 E is biased forward by the bias spring  54  described below. 
     The transmission gear section  51  is coupled to the discharge roller gear  52  described below and can be coupled to the driving mechanism  6  also described below. As a result, the transmission gear section  51  can couple the discharge roller gear  52  and the driving mechanism  6  together and cancel the coupling. The transmission gear section  51  has a function to transmit a rotational driving force transmitted from the driving mechanism  6 , to the discharge roller gear  52 . The transmission gear section  51  includes the first transmission gear  51 A and the second transmission gear  51 B. 
     The first transmission gear  51 A is axially supported by the first gear shaft  50 A so as to be rotatable. The first transmission gear  51 A can be coupled to an idler gear  62  of the driving mechanism  6  described below. The first transmission gear  51 A transmits a rotational driving force transmitted from the idler gear  62 , to the second transmission gear  51 B. 
     The second transmission gear  51 B is axially supported by the second gear shaft  50 B so as to be rotatable. The second transmission gear  51 B is coupled to the discharge roller gear  52 . The second transmission gear  51 B transmits a rotational driving force transmitted from the first transmission gear  51 A, to the discharge roller gear  52 . 
     The discharge roller gear  52  is arranged below the second transmission gear  51 B. The discharge roller gear  52  is a gear fixed to the roller shaft  31 A and to which a rotational driving force needed to rotate the discharge roller  31  is input. As shown in  FIG. 6 , the discharge roller gear  52  includes a D surface shaft section  52 A. The D surface shaft section  52 A projects from a side surface of the discharge roller gear  52 . The D surface shaft section  52 A is a generally cylindrical portion including an internal space shaped like the character D as viewed in cross section. As described above, the leading end portion of the roller shaft  31 A having penetrated the first bearing piece  50 D is inserted through the D surface shaft section  52 A. At this time, as shown in  FIG. 6 , the leading end portion of the roller shaft  31 A includes a D surface shape corresponding to the shape of the D surface shaft section  52 A. Thus, the discharge roller gear  52  is installed on the leading end portion of the roller shaft  31 A to enable the discharge roller gear  52  and the roller shaft  31 A to be integrally rotated. As a result, the discharge roller  31  rotates with the roller shaft  31 A. 
     The support frame  53  is a frame installed on the first support wall  402  of the guide unit  40 . The support frame  53  supports one end of the roller shaft  31 A. A space portion in which the rotational moving gear unit  5 A is rotationally movable is formed between the support frame  53  and the first support wall  402 . The support frame  53  includes a first slot  53 A, a second slot  53 B, and a first roller bearing section  53 C. A leading end portion of the first gear shaft  50 A having penetrated the first transmission gear  51 A is inserted into the first slot  53 A. Similarly, a leading end portion of the second gear shaft  50 B having penetrated the second transmission gear  51 B is inserted into the second slot  53 B. Furthermore, the first roller bearing section  53 C is a hole portion that axially supports the D surface shaft section  52 A so that the D surface shaft section  52 A is rotatable. 
     As shown in  FIG. 5  to  FIG. 8 , the rotational moving gear unit  5 A is rotationally movably supported between the first support wall  402  and the support frame  53 . As shown in  FIG. 7 , the first slot  53 A and the second slot  53 B are slots formed along the circumferential direction in the rotation of the rotational moving gear unit  5 A, which are formed so that the rotational moving gear unit  5 A can move rotationally. In conjunction with the rotational movement of the rotational moving gear unit  5 A, the first gear shaft  50 A moves along the first slot  53 A. Furthermore, the second gear shaft  50 B moves along the second slot  53 B. Additionally, above the second gear shaft  50 B, the first support shaft  303  is axially supported by the first support wall  402  as shown in  FIG. 8 . 
     The bias spring  54  is a coil spring compressively placed between a frame (not shown in the drawings) in the housing  200  and the pressed portion  50 E of the gear plate  50 . The bias spring  54  biases the gear plate  50  forward from the frame. In other words, the bias spring  54  biases the gear plate  50  in one direction around the roller shaft  31 A so as to couple the transmission gear section  51  to the driving mechanism  6  described below. 
     Moreover, the transmission mechanism  5  includes a pressing wall portion  306  (pressing portion). The pressing wall portion  306  separates from the pressed portion  50 E of the gear plate  50  in conjunction with a change in the position of the sheet guide  30  from the first position to the second position. As a result, the pressing wall portion  306  permits the transmission gear section  51  and the driving mechanism  6  to be coupled together under the biasing force of the bias spring  54 . On the other hand, the pressing wall portion  306  comes into abutting contact with the pressed portion  50 E of the gear plate  50  in conjunction with a change in the position of the sheet guide  30  from the second position to the first position. As a result, the pressing wall portion  306  rotates (rocks) the gear plate  50 , against the biasing force, in a direction opposite to the biasing direction of the bias spring  54  (the direction opposite to the one direction) around the roller shaft  31 A, separating the transmission gear section  51  from the driving mechanism  6 . The pressing wall portion  306  will further be described. The pressing wall portion  306  separates from the gear plate  50  when the sheet guide  30  is in the first position, to permit the transmission gear section  51  to couple to the driving mechanism  6  under the biasing force of the bias spring  54 . Furthermore, the pressing wall portion  306  comes into abutting contact with the gear plate  50  when the sheet guide  30  is in the second position, to uncouple, against the biasing force, the coupling between the transmission gear section  51  and the driving mechanism  6 . 
     Thus, according to the present embodiment, the pressing wall portion  306 , a part of the guide main body  300 , has a pressing portion function to bring the transmission gear section  51  into contact with the driving mechanism  6  and to separate the transmission gear section  51  from the driving mechanism  6 . The pressing wall portion  306  corresponds to a lower edge of the right (the other end portion on the sheet width direction) sidewall of the guide main body  300 . 
     Moreover, as shown in  FIG. 9  to  FIG. 11 , the sheet conveying section  3  includes the driving mechanism  6  ( FIG. 9 ) and an intermediate conveying gear  63  ( FIG. 10 ). Furthermore, the printer  100  includes a heating roller gear  131 A ( FIG. 10 ). Moreover, the sheet conveying section  3  includes the moving mechanism  7  (position change mechanism) ( FIG. 12  to  FIG. 15 ). 
     The driving mechanism  6  generates a rotational driving force that rotates the discharge roller  31 . Furthermore, according to the present embodiment, the driving mechanism  6  generates a rotational driving force that rotates the heating roller  131  of the fixing apparatus  130 . The driving mechanism  6  includes a driving motor  61  and an idler gear  62 . The driving motor  61  is a motor that generates the rotational driving force. The idler gear  62  is a gear coupled to a driving shaft (not shown in the drawings) of the driving motor  61 . The idler gear  62  is axially supported by the frame (not shown in the drawings) in the housing  200  so as to be rotatable. 
     The intermediate conveying gear  63  is located below and coupled to the idler gear  62 . The intermediate conveying gear  63  is a gear that transmits a rotational driving force to the intermediate conveying roller pair  33 . A rotational driving force generated by the driving motor  61  is transmitted to the intermediate conveying roller pair  33  via the idler gear  62  and the intermediate conveying gear  63 . 
     The heating roller gear  131 A is located in front of and coupled to the idler gear  62 . The heating roller gear  131 A is a gear that transmits a rotational driving force to the heating roller  131 . The heating roller gear  131 A is axially supported by the frame (not shown in the drawings) in the housing  200  so as to be rotatable. A rotational driving force generated by the driving motor  61  is transmitted to the heating roller  131  via the idler gear  62  and the heating roller gear  131 A. Then, as described above, the pressure roller  132  ( FIG. 2 ) rotates in conjunction with the heating roller  131  to covey the sheet S along the first conveying path SP 1  with a fixing process executed on the sheet S. 
     As shown in  FIG. 12  and  FIG. 15 , the moving mechanism  7  is arranged opposite a left end portion of the sheet guide  30  (one end side of the guide main body  300  in the sheet width direction). Furthermore, as shown in  FIG. 15 , the moving mechanism  7  is arranged on a right side of a rear wall left end portion  245 A. The rear wall left end portion  245 A is a wall portion formed by bending a left end portion of the rear wall  245  forward. In  FIG. 15 , illustration of the guide unit  40  ( FIG. 5 ) is omitted. 
     The moving mechanism  7  changes the position of the sheet guide  30  between the first position and the second position. Specifically, the moving mechanism  7  is coupled to one end side (left end side) of the guide main body  300  in the sheet width direction in order to induce the guide main body  300  to rotationally move around the first support shaft  303  and the second support shaft  304 . The moving mechanism  7  includes a solenoid  70  and a link  71 . The solenoid  70  performs a projecting and retracting operation in order to change the position of the sheet guide  30 . The solenoid  70  is controlled by a control section (not shown in the drawings) provided in the printer  100 . The solenoid  70  includes a main body section  70 A and a projecting and retracting shaft  70 B. The main body section  70 A is the main body section of the solenoid  70 . The projecting and retracting shaft  70 B is a shaft section provided to project upward from the main body section  70 A. The projecting and retracting shaft  70 B projects from and retracts into the main body section  70 A in the up-down direction. The link  71  is a link member that couples the guide main body  300  and the projecting and retracting shaft  70 B together. As shown in  FIG. 15 , a lower end portion of the link  71  is rotatably coupled to the projecting and retracting shaft  70 B. Similarly, an upper end portion of the link  71  is rotatably coupled to the engaging shaft section  305  of the guide main body  300 . 
     Now, operation of the transmission mechanism  5  in conjunction with a change in the position of the sheet guide  30  will be described. 
     As shown in  FIG. 3 , when the sheet S with a fixing process executed on the sheet S by the fixing apparatus  130  is discharged into the discharge section  210 , the control section (not shown in the drawings) controls the solenoid  70  to retract the projecting and retracting shaft  70 B as shown in  FIG. 14 . At this time, the link  71  coupled to the projecting and retracting shaft  70 B has lowered the engaging shaft section  305  downward, and thus, the leading end portion (lower end portion) of the guide main body  300  extends downward ( FIG. 12 ). As a result, as shown in  FIG. 3 , the sheet S is conveyed into the second conveying path SP 2  (arrow D 31  in  FIG. 3 ) while being guided by the sheet guide  30  and discharged into the sheet discharge section  210 . 
     At this time, as shown in  FIG. 12 , the pressing wall portion  306  of the sheet guide  30  biases the pressed portion  50 E rearward against the biasing force of the bias spring  54 . Thus, the gear plate  50  is rotationally moved rearward using the roller shaft  31 A as a pivot ( FIG. 12 ), separating the first transmission gear  51 A from the idler gear  62  ( FIG. 10 ). In this case, a rotational driving force generated by the driving mechanism  6  is transmitted to the heating roller  131  via the idler gear  62  and the heating roller gear  131 A (arrows D 102 , D 103 , and D 104  in  FIG. 10 ). Furthermore, the intermediate conveying roller pair  33  is rotated via the intermediate conveying gear  63 . On the other hand, the first transmission gear  51 A is separate from the idler gear  62 , and thus, the rotational driving force of the idler gear  62  is not transmitted to the first transmission gear  51 A. Thus, the discharge roller gear  52  is prevented from rotating, with the rotation of the discharge roller  31  stopped. 
     As described above, when the sheet S is discharged into the sheet discharge section  210  via the second conveying path SP 2 , unwanted rotation of the discharge roller  31  is prevented. As a result, possible wear of and damage to the discharge roller  31  and possible noise are prevented which are involved in the unwanted rotation. 
     On the other hand, in the state shown in  FIG. 3 ,  FIG. 10 ,  FIG. 12 , and  FIG. 14  (the first position of the sheet guide  30 ), when the destination into which the sheet S is discharged is set to the discharge opening  245 S ( FIG. 3 ), the position of the sheet guide  30  is changed to the second position. That is, the control section (not shown in the drawings) controls the solenoid  70  to project the projecting and retracting shaft  70 B from the main body section  70 A (arrow D 121  in  FIG. 12  and arrow D 141  in  FIG. 14 ). As a result, the link  71  coupled to the projecting and retracting shaft  70 B pushes the engaging shaft section  305  upward. Then, the guide main body  300  moves rotationally around the first support shaft  303  and the second support shaft  304  (arrow D 142  in  FIG. 14 ) so as to move the leading end portion of the guide main body  300  upward. As a result, the sheet guide  30  is placed into the second position shown in  FIG. 4 ,  FIG. 13 , and  FIG. 15 . 
     As the position of the sheet guide  30  changes, the pressing wall portion  306  ( FIG. 12 ) of the guide main body  300  moves forward away from the pressed portion  50 E. As a result, the gear plate  50  is rotationally moved, by the biasing force of the bias spring  54 , in the direction of arrow D 122  in  FIG. 12  using the roller shaft  31 A as a pivot. At this time, the first transmission gear  51 A moves in the direction of arrow D 101  in  FIG. 10  to couple to the idler gear  62  ( FIG. 11 ). 
     When the driving motor  61  is rotated by the control section (not shown in the drawings), the heating roller  131  is rotated via the idler gear  62  and the heating roller gear  131 A (arrows D 112 , D 113 , and D 114  in  FIG. 11 ). Furthermore, the intermediate conveying roller pair  33  is rotated via the intermediate conveying gear  63 . Moreover, a rotational driving force is transmitted from the idler gear  62  to the first transmission gear  51 A to rotate the second transmission gear  51 B and the discharge roller gear  52  (arrows D 115 , D 116 , and D 117  in  FIG. 11 ). As a result, the discharge roller gear  52  and the roller shaft  31 A rotate integrally to rotate the discharge roller  31  in the direction of arrow D 133  in  FIG. 13 . Thus, when the sheet S is conveyed into the third conveying path SP 3  by the sheet guide  30  placed in the second position ( FIG. 4 ), the discharge roller  31  is rotated by the driving mechanism  6 . As a result, the sheet S is stabilized and conveyed along the third conveying path SP toward the discharge opening  245 S ( FIG. 4 ) and then discharged through the discharge opening  245 S (arrow D 41  in  FIG. 4 ). 
     Similarly, in the state shown in  FIG. 4 ,  FIG. 11 ,  FIG. 13 , and  FIG. 15  (the second position of the sheet guide  30 ), when the destination into which the sheet S is discharged is set to the sheet discharge section  210  again, the position of the sheet guide  30  is changed to the first position. That is, the control section (not shown in the drawings) controls the solenoid  70  to retract the projecting and retracting shaft  70 B into the main body section  70 A (arrow D 131  in  FIG. 13  and arrow D 151  in  FIG. 15 ). As a result, the link  71  coupled to the projecting and retracting shaft  70 B pushes the engaging shaft section  305  downward. Then, the guide main body  300  moves rotationally around the first support shaft  303  and the second support shaft  304  (arrow D 152  in  FIG. 15 ) so as to move the leading end portion of the guide main body  300  downward. As a result, the sheet guide  30  is placed into the first position again shown in  FIG. 3 ,  FIG. 12 , and  FIG. 14 . 
     As the position of the sheet guide  30  changes, the pressing wall portion  306  of the guide main body  300  ( FIG. 12 ) moves rearward and comes into abutting contact with the pressed portion  50 E. As a result, the gear plate  50  moves rotationally in the direction of arrow D 132  in  FIG. 13  using the roller shaft  31 A as a pivot while compressing the bias spring  54 . At this time, the first transmission gear  51 A moves in the direction of arrow D 111  in  FIG. 11  to separate from the idler gear  62  ( FIG. 10 ). Thus, the force required for the solenoid  70  to switch the position of the sheet guide  30  is preset higher than the biasing force of the bias spring  54 . 
     As described above, according to the present embodiment, the discharge roller  31  is rotated in association with the case where the sheet S is conveyed into the third conveying path SP 3 . Thus, the unwanted rotation of the discharge roller  31  is prevented. Furthermore, the transmission of the rotational driving force to the discharge roller  31  can be switched by coupling the transmission gear section  51  and the driving mechanism  6  together and uncoupling the coupling. Moreover, the gear plate  50 , the bias spring  54 , and the pressing wall portion  306  enable the coupling of the transmission gear section  51  and the driving mechanism  6  and cancellation of the coupling. In particular, the rotational movement of the gear plate  50  utilizing the roller shaft  31 A as a hinged pivot makes a space occupied by the sheet conveying section  3  as small as possible, while enabling the coupling and the cancellation of the coupling. Moreover, rotational movement of the gear plate  50  allows the transmission of the rotational driving force to the discharge roller gear  52  to be switched without moving the axial position of the roller shaft  31 A, which supports the discharge roller  31 . 
     Furthermore, in the present embodiment, a part of the sheet guide  30  is utilized as a pressing portion that rotationally moves the gear plate  50 , allowing the transmission gear section  51  to be separated from the driving mechanism  6 . Thus, compared to a case where another pressing portion is adopted, the present embodiment enables the transmission mechanism  5  to be made more compact. Additionally, the gear plate  50  can be rotationally moved utilizing the turning force of the sheet guide  30 , rotated around the first support shaft  303  and the second support shaft  304  by the moving mechanism  7 . 
     Furthermore, according to the present embodiment, the moving mechanism  7  is arranged on one end side of the guide main body  300  of the sheet guide  30 , and the transmission mechanism  5  is arranged on the other end side of the guide main body  300 . Thus, the opposite end sides of the sheet guide  30  in the sheet width direction are effectively utilized. The space occupied by the sheet conveying section  3  is made as small as possible, with coupling of the transmission gear section  51  and the driving mechanism  6  and cancellation of the coupling enabled. Additionally, a part of the other end side of the guide main body  300  can be utilized to separate the transmission gear section  51  from the driving mechanism  6 . 
     Moreover, according to the present embodiment, the sheet S with a fixing process executed thereon is selectively conveyed to the two conveying paths (second conveying path SP 2  and third conveying path SP 3 ). Furthermore, the driving mechanism  6  has both the function to rotationally drive the heating roller  131  of the fixing apparatus  130  and the function to rotationally drive the discharge roller  31 . In other words, the discharge roller  31  can be selectively rotated utilizing the driving mechanism  6  that rotates the heating roller  131 . Then, the sheet S with the fixing process executed thereon is selectively discharged into the sheet discharge section  210  arranged in the upper portion of the housing  200  or into the discharge opening  245 S (side discharge section) arranged in the rear wall  245  located on the rear side of the housing  200 . 
     The sheet conveying section  3  and the printer  100  (image forming apparatus) having the same according to the embodiment of the disclosure have been described. However, the disclosure is not limited to the embodiment. For example, the following variations are possible. 
     (1) According to the embodiment, the moving mechanism  7  that changes the position of the sheet guide  30  has been described using the solenoid  70 . However, the disclosure is not limited to this. Another moving mechanism (position change mechanism) such as a driving motor or a cam mechanism may be applied as the moving mechanism  7 . 
     (2) Furthermore, in the embodiment, the aspect has been described in which the transmission gear section  51  that transmits a rotational driving force to the discharge roller gear  52  includes two gears, the first transmission gear  51 A and the second transmission gear  51 B. However, the disclosure is not limited to this. The transmission gear section  51  may include one gear or three or more gears. 
     (3) Additionally, in the embodiment, the aspect has been described in which the sheet conveying section  3  conveys the sheet S with a fixing process executed on the sheet S by the fixing apparatus  130 . However, the disclosure is not limited to this. The sheet conveying section  3  may be applied to another conveying area in which the sheet S is conveyed from the first conveying path SP 1  to the second conveying path SP 2  or the third conveying path SP 3 . In addition, the sheet conveying section  3  may be applied to a post-processing apparatus with a sort function to allow the sheet S to be selectively discharged to a plurality of destinations. 
     Although the present disclosure has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present disclosure hereinafter defined, they should be construed as being included therein.