Patent Publication Number: US-2020276846-A1

Title: Printing apparatus

Description:
The present application is based on, and claims priority from JP Application Serial Number 2019-037294, filed Mar. 1, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a printing apparatus. 
     2. Related Art 
     In a known printing apparatus that houses a recording medium such as roll paper, a housing portion is covered with a cover that opens and closes with one end as a rotational movement center (see, for example, U.S. Pat. No. 8,985,730). 
     In the printing apparatus, work for housing and mounting a consumable item such as a recording medium may be limited by an opening direction of the cover. For example, when a continuous sheet is used as the recording medium, the cover of the housing portion is opened and the continuous sheet is set in the printing apparatus. 
     However, the cover that covers the housing portion opens in one direction, and the opening direction is only one. Thus, it may be difficult to perform the work from a direction opposite to the opening direction. Further, when the printing apparatus is arranged in consideration of the working operation, an arrangement place of the printing apparatus may be constrained. 
     The present disclosure has been made in view of the above-mentioned problem, and an object thereof is to facilitate, in an apparatus that performs printing on a recording medium, work for housing the recording medium into the apparatus, and the like. 
     SUMMARY 
     One aspect for solving the above-described problem is a printing apparatus including a housing portion configured to house a recording medium, a transport unit configured to transport the recording medium from the housing portion to a printing unit, and a cover configured to open and close the housing portion, where the cover is rotatably supported by a first support shaft and a second support shaft, the first support shaft is disposed in a position closer to the printing unit than to the housing portion, and the second support shaft is disposed in a position farther from the printing unit than from the housing portion, and the cover is configured such that, when displaced from a closed position in a first direction, the cover is spaced from the second support shaft and is rotationally movable around the first support shaft up to a first open position, and that, when displaced from the closed position in a second direction, the cover is spaced from the first support shaft and is rotationally movable around the second support shaft up to a second open position. 
     In the printing apparatus described above, the transport unit may be configured to transport an external recording medium to the printing unit, the cover in the first open position may form, in the housing portion, an opening through which the recording medium is insertable to the housing portion, and also open, at one end of the housing portion, an insertion opening that guides the external recording medium into a printing apparatus main body, and the cover in the second open position may form, in the housing portion, an opening through which the recording medium and the external recording medium are loadable on the transport unit. 
     Further, the printing apparatus described above may further include a first engagement member provided at the cover, and configured to engage with the first support shaft such that the cover is rotationally movable from the closed position of the cover to the first open position, and disengage from the first support shaft by moving with respect to the first support shaft, and a second engagement member provided at the cover, and configured to engage with the second support shaft such that the cover is rotationally movable from the closed position of the cover to the second open position, and disengage from the second support shaft by moving with respect to the second support shaft. 
     The printing apparatus described above may further include a first spur gear provided at the cover, and configured to mesh with a first internal gear, provided at a peripheral portion of the first support shaft and rotate, due to a rotational movement of the cover around the first support shaft, a first damper configured to apply a load to rotation of the first spur gear, a second spur gear provided at the cover, and configured to mesh with a second internal gear, provided at a peripheral portion of the second support shaft, and rotate due to a rotational movement of the cover around the second support shaft, and a second damper configured to apply a load to rotation of the second spur gear. 
     In the printing apparatus described above, the second support shaft may be located in a direction opposite to a discharge direction of the recording medium with respect to the first support shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view illustrating an internal structure of a printing apparatus loaded with fanfold paper. 
         FIG. 2  is a back view of the printing apparatus. 
         FIG. 3  is a side view of a main portion illustrating an engagement mechanism of a front support portion and a cover front portion. 
         FIG. 4  is a side view of a main portion illustrating an engagement mechanism of a rear support portion and a cover rear portion. 
         FIG. 5  is an explanatory diagram illustrating an operation of a buffering mechanism of the cover rear portion. 
         FIG. 6  is a side view illustrating an internal structure of the printing apparatus loaded with roll paper. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings. In the drawings, a reference sign Up represents an upper side, a reference sign Fr represents a front side, and a reference sign Rh represents a right side. 
     As illustrated in  FIG. 1 , a printing apparatus  1  includes a printing apparatus main body  10 . The printing apparatus main body  10  is provided with a printing unit  20  that performs printing on a recording medium, a housing portion  21  that houses the recording medium, and a cover  60  that covers the housing portion  21 . In the printing apparatus main body  10 , the housing portion  21  is provided behind the printing unit  20 . 
     A sheet P illustrated in  FIG. 1  is fanfold paper  101 . The sheet P is guided to a paper guide  33  and a paper holder  34 , and is fed to the printing unit  20  on the front side. The sheet P printed by the printing unit  20  is discharged from a paper exit  22  formed on a front surface of the printing apparatus  1 . The paper guide  33  is a rest that supports the sheet P from below. The paper holder  34  is located above the sheet P so as to face the paper guide  33 , and holds down floating of the sheet P. 
     The printing unit  20  is disposed in front of the paper guide  33  and the paper holder  34 . The printing unit  20  includes a platen  35 , a printing head  40 , and carriage guide shafts  41  and  42 . The printing head  40  in the present exemplary embodiment can spray ink in a plurality of colors. As the ink that can be sprayed, for example, ink in four colors of cyan, magenta, yellow, and black can be sprayed onto the sheet P. The ink is stored in an ink cartridge  24 . 
     The ink cartridge  24  is disposed in a front lower portion of the printing apparatus main body  10 . An ink supply unit  23  is provided in a front upper portion of the printing apparatus main body  10 . The ink in the ink cartridge  24  is supplied to the printing head  40  via the ink supply unit  23 . The printing head  40  performs scanning along the carriage guide shafts  41  and  42  disposed in a left-and-right width direction of the printing apparatus  1 , and performs printing on the sheet P. Further, a substrate  25  that controls an operation of the printing apparatus  1  is disposed in front of the ink cartridge  24 . 
     The platen  35  of the printing unit  20  has a flat surface disposed along a transport direction F. This flat surface is located below a transport path  110  of the sheet P, and faces the printing head  40 . The platen  35  is fixed to the printing apparatus main body  10  of the printing apparatus  1 , and supports the sheet P from below. The flat surface of the platen  35  is substantially horizontal in an installation state and a use state of the printing apparatus  1 . A transport belt  52  passes over the flat surface of the platen  35 . The transport belt  52  is a wide and endless-shaped belt, and is disposed so as to go around to the lower side of the platen  35  from above the flat surface of the platen  35  via a roller  52   a.    
     Of a front surface of the transport belt  52 , at least a surface facing upward on the flat surface of the platen  35  is a rough surface with a high coefficient of friction. The transport belt  52  may be formed of an elastic material such as rubber and synthetic resin. A drive mechanism (not illustrated) that moves the transport belt  52  is disposed below the platen  35 . 
     A driven roller (not illustrated) is disposed between the printing head  40  and the paper holder  34  so as to face the platen  35 . 
     The driven roller is rotatably supported on the printing apparatus main body  10  of the printing apparatus  1 . The driven roller is biased toward the flat surface of the platen  35 . In the transport path  110 , the sheet P is sandwiched between the driven roller (not illustrated) and the transport belt  52 , and is reliably transported in the transport direction F as the transport belt  52  moves. 
     Further, a holding roller (not illustrated) that holds down the sheet P so as to prevent floating of the sheet P from the transport belt  52  is disposed on the printing head  40 . The paper guide  33 , the paper holder  34 , the transport belt  52 , the roller  52   a , and the mechanism for driving the transport belt  52  constitute a transport unit  30  that transports the sheet P to the printing unit  20 . 
     A cutter unit for cutting the sheet P can be mounted on the front surface of the printing apparatus main body  10 . The cutter unit may make a cut while leaving a part of the sheet P in the width direction, or may completely cut the sheet P. The printing apparatus  1  cuts the sheet P printed by the printing head  40  to a predetermined length by the cutter unit, and can discharge the sheet P from the paper exit  22 . 
     A winding unit (not illustrated) can be attached to and detached from the front surface of the printing apparatus main body  10  below the paper exit  22 . The winding unit includes a winding drum that winds the sheet P discharged from the paper exit  22 , and a drive unit (not illustrated) that rotates the winding drum, and the winding unit can wind the sheet P. A peeler may be attached to the front surface of the printing apparatus main body  10 . The peeler can wind release paper while removing a label from the release paper. 
     The housing portion  21  having an open upper portion is provided in the rear portion of the printing apparatus main body  10 . The housing portion  21  is disposed behind the printing unit  20 . The paper guide  33  and the paper holder  34  are disposed in the housing portion  21 . The housing portion  21  is covered by the cover  60 . 
     According to the present exemplary embodiment, the cover  60  is supported by a front support portion  11  and a rear support portion  12  so as to be freely open and closed in two directions R 1  and R 2 . A rear portion  60   r  of the cover  60  is rotationally moved in the first direction R 1  with respect to the front support portion  11 , and the cover  60  is rotationally moved to a first open position C 1 . Further, a front portion  60   f  of the cover  60  is rotationally moved in the second direction R 2  with respect to the rear support portion  12 , and the cover  60  is rotationally moved to a second open position C 2 . 
       FIG. 2  is a back view of the printing apparatus. 
     As illustrated in  FIG. 2 , an insertion opening  71  is formed in a rear surface of the printing apparatus  1  with the cover  60  being closed. The insertion opening  71  is formed between a notch  60   n  provided in a lower portion of the rear portion  60   r  and a rear upper edge  6   a  of an outer packaging  6  of the printing apparatus  1 . The insertion opening  71  is formed in an upper portion of a rear end of the housing portion  21 . 
     As illustrated in  FIG. 1 , the fanfold paper  101  passes through the insertion opening  71  that communicates with the housing portion  21 , and is supplied to the inside of the printing apparatus  1 . 
     The notch  60   n  is formed open to a position exceeding a height of a second support shaft  12   a , which will be described later, in a position C 0  in which the cover  60  illustrated in  FIG. 1  is closed. In this way, with the cover  60  being open to the second open position C 2 , the insertion opening  71  is formed between the notch  60   n  and the outer packaging  6 . Therefore, even when the cover  60  is located in the second open position C 2 , the insertion opening  71  is exposed to the rear, and thus the sheet P can pass through the insertion port  71  and the printing apparatus  1  can be loaded with the fanfold paper  101 . 
     Further, the rear portion  60   r  of the cover  60  is rotationally moved in the first direction R 1  with respect to the front support portion  11 , and the cover  60  is rotationally moved to the first open position C 1 . When the cover  60  is rotationally moved to the first open position C 1 , the housing portion  21  and an opening surrounded by the cover  60  in the first open position C 1  open greatly toward the rear of the printing apparatus  1 . In this way, even when the cover  60  is located in the first open position C 1 , the fanfold paper  101  disposed behind the printing apparatus  1  can be more easily loaded from the rear of the printing apparatus  1 . 
       FIG. 3  is a side view of a main portion illustrating an engagement mechanism A of the front support portion  11  and the front portion  60   f  of the cover  60 . The front portion  60   f  of the cover  60  is disposed between the front support portions  11  provided on left and right side portions of the printing apparatus main body  10 . A first support shaft  11   a  that extends toward the cover  60  is provided on each of the left and right front support portions  11 . Each of the left and right first support shafts  11   a  together with the second support shaft  12   a , which will be described later, constitute a support shaft portion  60   a  that rotatably supports the cover  60 . 
     When the front portion  60   f  of the cover  60  is opened, engagement between the engagement mechanism A and the first support shaft  11   a  is released, and the front portion  60   f  is separated from the front support portion  11 . 
     The first support shaft  11   a  is a short pin protruding toward the cover  60 . An extension direction of the first support shaft  11   a  coincides with the left-and-right direction of the printing apparatus  1 . 
     The engagement mechanism A is constituted by a first engagement member  65  that engages with the first support shaft  11   a , a front rod  64   f  that is a rotational movement shaft of the first engagement member  65 , and a front lever  66   f  that releases the engagement. The first engagement members  65  provided on the left and right of the front portion  60   f  of the cover  60  are fixed to left and right end portions of the front rod  64   f  so as to be relatively rotationally immovable. 
     The front lever  66   f  is fixed to the center of the front rod  64   f , and the front lever  66   f  is rotatably supported on the cover  60  with the front rod  64   f  as a rotational movement shaft. 
     In the position C 0  illustrated in  FIG. 1  in which the cover  60  is closed, the first support shaft  11   a  fits into a guide groove  67  provided on each of left and right side surfaces of the front portion  60   f , and is engaged by the first engagement member  65 . The first engagement member  65  is configured to have a hook shape in which a tip portion is curved in a rotational movement direction. The first engagement member  65  is movable between an engagement position A 1  and a release position A 2 . 
     The first engagement member  65  is biased by a biasing member (not illustrated) so as to move from the release position A 2  to the engagement position A 1 . 
     The guide groove  67  is provided obliquely downward on a partway portion in a thickness direction of the front portion  60   f  in a closed state of the cover  60 . 
     When the front portion  60   f  of the cover  60  is closed, the first support shaft  11   a  is introduced into the guide groove  67  from a lower end portion  67   b  of the guide groove  67 . Then, the first support shaft  11   a  abuts the first engagement member  65 , and rotationally moves the first engagement member  65  toward the release position A 2 . When the first support shaft  11   a  reaches an upper end portion  67   a  of the guide groove  67 , the first engagement member  65  returns to the engagement position A 1 . Then, the first support shaft  11   a  is held between the upper end portion  67   a  of the guide groove  67  and the first engagement member  65 . In this way, the engagement mechanism A and the first support shaft  11   a  engage with each other. 
     In the engagement position A 1 , the first engagement member  65  protrudes from a rear surface  67   c  of the guide groove  67  toward the guide groove  67 . In the guide groove  67 , the first engagement member  65  is configured to have a shape in which the amount of protrusion into the guide groove  67  is reduced toward the lower end portion  67   b  of the guide groove  67 . 
     When the front portion  60   f  of the cover  60  is closed, the front portion  60   f  is rotationally moved downward around the second support shaft  12   a  illustrated in  FIG. 2 . In this way, the first support shaft  11   a  is introduced into the guide groove  67 , and the first support shaft  11   a  pushes and rotationally moves the first engagement member  65 . Then, when the first support shaft  11   a  reaches the upper end portion  67   a  of the guide groove  67 , the first engagement member  65  protrudes into the guide groove  67 , and the first support shaft  11   a  is locked by the first engagement member  65  and the guide groove  67 . 
     When the cover  60  opens from the front portion  60   f , the locking of the first support shaft  11   a  is released. At this time, the front lever  66   f  is rotationally moved upward around the front rod  64   f . In this way, the front lever  66   f  and the first engagement member  65  move to the release position A 2 . 
     Then, the first engagement member  65  retracts from the inside of the guide groove  67 . In this way, the locking of the first support shaft  11   a  is released, and the front portion  60   f  of the cover  60  can rotationally move in the second direction R 2  with the first support shaft  11   a  fitted in the guide groove  67 . 
     In the present exemplary embodiment, a buffering mechanism  70  as a gear wheel train that buffers a rotational movement around the front portion  60   f  is provided around the first support shaft  11   a . The buffering mechanism  70  is constituted by a first internal gear  73  provided on an upper end portion of the front support portion  11  of the printing apparatus  1 , a first spur gear  72  provided on the front portion  60   f  of the cover  60 , an intermediate gear  74 , a first damper  76 , and a damper gear  75  attached to a rotary shaft of the first damper  76 . 
     The first spur gear  72  is rotatably supported by the cover  60 . A rotational movement shaft of the first spur gear  72  coincides with the left-and-right direction of the printing apparatus  1 . The intermediate gear  74  meshing with the first spur gear  72  transmits the rotation of the first spur gear  72  to the first damper  76  via the damper gear  75 . For example, a rotary damper using a flow resistance or a rotary damper using a frictional resistance can be used as the first damper  76 . The first internal gear  73  is a peripheral portion of the first support shaft  11   a , and is provided on a circumferential portion. The first internal gear  73  is formed on an arc centered around the first support shaft  11   a  on the upper end portion of the front support portion  11 . 
     The first spur gear  72  is disposed such that a part of the first spur gear  72  protrudes forward with respect to the front portion  60   f  with the cover  60  in the closed position C 0 . 
     When the cover  60  rotationally moves at equal to or greater than a predetermined angle around the first support shaft  11   a , the first spur gear  72  meshes with the first internal gear  73 , and the first spur gear  72  rotates. Then, the first damper  76  applies a load to the rotation of the first spur gear  72  and buffers the rotational movement of the cover  60 . The predetermined angle is appropriately set by a shape of the cover  60 . 
     In the buffer mechanism  70  of the front portion  60   f , a range in which the first spur gear  72  and the first internal gear  73  do not mesh with each other is provided. A straight line F 1  is a straight line passing through the rotation center of the first spur gear  72  and the first support shaft  11   a  with the cover  60  in the closed position C 0 . A straight line F 2  is a straight line passing through the rotation center of the first spur gear  72  and the first support shaft  11   a  in a state in which the first spur gear  72  starts to contact the first internal gear  73 . A straight line F 3  is a straight line passing through the rotation center of the first spur gear  72  and the first support shaft  11   a  with the cover  60  in the second open position C 2 . 
     In a rotational movement range G 1  from the straight line F 1  to the straight line F 2 , the first spur gear  72  does not contact the first internal gear  73 , and the first damper  76  does not operate. An angle of the rotational movement range G 1  is a predetermined angle G 1  at which the first spur gear  72  and the first internal gear  73  do not contact each other. Further, the rotational movement range G 1  may be set to be a range from the closed position C 0  of the cover  60  to a rotational movement position in which the second support shaft  12   a  and a second engagement member  68  contact each other. In this way, when the cover  60  changes its posture due to contact with the second support shaft  12   a , a load is less likely to be applied to the first spur gear  72  and the first internal gear  73 . 
     In a rotational movement range G 2  from the straight line F 2  to the straight line F 3 , the first spur gear  72  contacts the first internal gear  73 , and the first damper  76  operates. In such a manner, the rotational movement range G 1  in which the first damper  76  does not operate and the rotational movement range G 2  in which the first damper  76  operates are sequentially provided between the closed position C 0  of the cover  60  and the second open position C 2 . 
       FIG. 4  is a side view of a main portion illustrating an engagement mechanism B of the rear support portion  12  and the rear portion  60   r  of the cover  60 . The engagement mechanism B is constituted by the second engagement member  68 , a rear rod  64   r  that is a rotational movement shaft of the second engagement member  68 , and a rear lever  66   r  that integrally rotationally moves with the second engagement member  68 . The second engagement member  68  is fixed to the rear rod  64   r . The second engagement members  68  are fixed to left and right end portions of the rear rod  64   r  so as to be relatively rotationally immovable. Further, the rear lever  66   r  is fixed to a central portion of the rear rod  64   r . The rear lever  66   r  is rotatably supported on the cover  60  with the rear rod  64   r  as a rotational movement shaft. 
     The rear portion  60   r  of the cover  60  is disposed between the rear support portions  12  provided on the left and right side portions of the printing apparatus  1 . Each of the second support shafts  12   a  that extend toward the cover  60  is provided on the rear support portion  12 . Each of the left and right second support shaft  12   a  together with the first support shaft  11   a  constitute the support shaft portion  60   a  that rotatably supports the cover  60 . The second support shaft  12   a  is a short pin protruding toward the cover  60 . Then, an extension direction of the second support shaft  12   a  coincides with the left-and-right direction of the printing apparatus  1 . When the rear portion  60   r  of the cover  60  is opened, engagement between the engagement mechanism B and the second support shaft  12   a  is released, and the rear portion  60   r  is separated from the rear support portion  12 . 
     With the cover  60  in the closed position C 0 , the second support shaft  12   a  fits into a guide groove  69  provided in the cover  60  and is locked by the second engagement member  68 . 
     The guide groove  69  is provided in left and right side surfaces of the rear portion  60   r  of the cover  60 . The guide groove  69  is provided obliquely downward on a lower end portion of the rear portion  60   r  in the closed state of the cover  60 . A lower end portion  69   b  of the guide groove  69  opens downward. When the cover  60  is closed, the second support shaft  12   a  is introduced into the guide groove  69  from the lower end portion  69   b  of the guide groove  69 . The second support shaft  12   a  is locked by an upper end portion  69   a  of the guide groove  69  and the second engagement member  68 . 
     The second engagement member  68  is configured to have a hook shape in which a tip portion is curved in a rotational movement direction. The second engagement member  68  is movable between an engagement position B 1  and a release position B 2 . The second engagement member  68  is biased by a spring  68   a  so as to be rotationally moved from the release position B 2  to the engagement position B 1 . 
     The second engagement member  68  protrudes into the guide groove  69  from a front surface  69   c  of the guide groove  69 . The portion of the second engagement member  68  protruding into the guide groove  69  is configured such that the amount of protrusion into the guide groove  69  is reduced toward the lower end portion  69   b  of the guide groove  69 . 
     In this way, when the rear portion  60   r  of the cover  60  is closed, the second support shaft  12   a  is introduced into the guide groove  69  and pushes the second engagement member  68 , and thus rotationally moves the second engagement member  68  from the engagement position B 1  to the release position B 2 . 
     Then, when the second support shaft  12   a  reaches the upper end portion  69   a  of the guide groove  69 , the second engagement member  68  protrudes into the guide groove  69 , and the second support shaft  12   a  is locked by the second engagement member  68  and the guide groove  69 . 
     When the rear portion  60   r  of the cover  60  is opened, the locking of the second support shaft  12   a  is released. By rotationally moving the rear lever  66   r  upward, the second engagement member  68  retracts from the inside of the guide groove  69 , and moves from the engagement position B 1  to the release position B 2 . In this way, the locking of the second support shaft  12   a  is released, and the second support shaft  12   a  is movable within the guide groove  69 . 
     In the present exemplary embodiment, a buffering mechanism  80  configured as a gear wheel train that buffers a rotational movement around the rear portion  60   r  is provided. 
     The buffering mechanism  80  is constituted by a second internal gear  83  and a second spur gear  82  that are provided on an upper end portion of the rear support portion  12 , an intermediate gear  84 , a second damper  86 , and a damper gear  85  that rotationally moves integrally with a rotational movement shaft of the second damper  86 . 
     The second spur gear  82 , the intermediate gear  84 , and the second damper  86  are provided on the rear portion  60   r  of the cover  60 . The second internal gear  83  is a peripheral portion of the second support shaft  12   a , and is provided on a circumferential portion. The second internal gear  83  is formed on an arc centered around the second support shaft  12   a  on the upper end portion of the rear support portion  12 . 
     The second spur gear  82  is rotatably supported by the rear portion  60   r  of the cover  60 . A rotational movement shaft of the second spur gear  82  coincides with the left-and-right direction of the printing apparatus  1 . The intermediate gear  84  meshing with the second spur gear  82  transmits the rotation of the second spur gear  82  to the second damper  86 . Then, the second damper  86  buffers the rotational movement of the second spur gear  82 . 
     The second spur gear  82  is disposed such that a part thereof protrudes downward with respect to the rear portion  60   r . Then, when the cover  60  rotationally moves at equal to or greater than a predetermined angle around the second support shaft  12   a , the second spur gear  82  meshes with the second internal gear  83 , and the second spur gear  82  rotates. Then, the second damper  86  applies a load to the rotation of the second spur gear  82 , and buffers the rotational movement of the cover  60 . Further, the rotational movement by an empty weight of the cover  60  can be prevented by setting of the second damper  86 . The predetermined angle is appropriately set by a shape of the cover  60 . 
     Next, an operation of the buffering mechanisms  70  and  80  will be described. 
       FIG. 5  is an explanatory diagram illustrating the operation of the buffering mechanism  80  of the rear portion  60   r  of the cover  60 . In  FIG. 5 , a state S 1  indicates a state in which the cover  60  is closed. 
     In this state S 1 , the second spur gear  82  and the second internal gear  83  do not mesh with each other, and the second damper  86  of the rear portion  60   r  is not in operation. 
     A state S 2  indicates a state in which the front portion  60   f  of the cover  60  is rotationally moved upward, and the second spur gear  82  and the second internal gear  83  start to mesh with each other. When the second spur gear  82  and the second internal gear  83  start to mesh with each other, the second damper  86  starts to operate. 
     A state S 3  indicates a state in which a maximum rotational movement state to the rear of the cover  60 . The state S 3  indicates a state in which the cover  60  is opened to the second, open position C 2 . In the state S 3 , the rotational movement of the cover  60  into the second direction R 2  is regulated by a stopper (not illustrated). A straight line L 1  is a straight line that connects the second support shaft  12   a  and a rotary shaft  82   a  of the second spur gear  82  in the state S 1 . A straight line L 2  is a straight line that connects the second support shaft  12   a  and the rotary shaft  82   a  in the state S 2 . A straight line L 3  is a straight line that connects the second support shaft  12   a  and the rotary shaft  82   a  in the state S 3 . 
     The cover  60  is rotationally moved from the state S 1  to the state S 3  with the second support shaft  12   a  as a rotational movement center. In a range from the state S 1  to the state S 3 , a range in which the second damper  86  does not work is provided. In the rotational movement range H 1  of the cover  60  from the state S 1  to the state S 2 , the second spur gear  82  does not contact the second internal gear  83 . An angle of a rotational movement range H 1  is a predetermined angle H 1  at which the second spur gear  82  and the second internal gear  83  do not contact each other. 
     Then, in a rotational movement range H 2  of the cover  60  from the state S 2  to the state S 3 , the second spur gear  82  contacts the second internal gear  83 . 
     In the rotational movement range H 1 , the second spur gear  82  and the second internal gear  83  do not mesh with each other. Thus, in the rotational movement range H 1 , the second damper  86  does not operate. 
     When the cover  60  is opened with the second support shaft  12   a  as the rotational movement center, the front lever  66   f  of the front portion  60   f  is lifted. The front lever  66   f  is lifted, and the engagement between the engagement mechanism A and the first support shaft  11   a  is released. The front portion  60   f  rotationally moves in the second direction R 2 . The second damper  86  does not operate until the engagement with the first support shaft  11   a  is sufficiently released, and thus an operation in the rotational movement range H 1  for opening the front portion  60   f  can be performed smoothly. 
     In the rotational movement range H 2 , the second spur gear  82  meshes with the second internal gear  83 . At this time, the second spur gear  82  meshes with the second internal gear  83  while rotating in the rotation direction R 3 . 
     In this way, the second spur gear  82  is rotationally moved by the rotational movement of the cover  60 , and a driving force is transmitted to the second damper  86  via the intermediate gear  84  and the damper gear  85 . Then, the second damper  86  operates, and a load is applied to the rotational movement of the cover  60 . Thus, when the cover  60  is rotationally moved in the rotational movement range H 2 , the behavior of the cover  60  during the rotational movement is stabilized by the second damper  86 . Further, sudden opening and closing of the cover  60  are suppressed. 
     When the cover  60  is closed with the second support shaft  12   a  as the rotational movement center, a state in which the second damper  86  operates in the rotational movement range H 2  changes to a state in which the second damper does not operate in the rotational movement range H 1 , and the first support shaft  11   a  can easily engage with the cover  60 . In this way, the cover  60  can be reliably closed. Further, the front portion  60   f  of the cover  60  can be closed by using an empty weight of the cover  60 . The rotational movement range H 1  may be set to be a range from the closed position C 0  of the cover  60  to a rotational movement position in which the first support shaft  11   a  and the first engagement member  65  contact each other. In this way, when the cover  60  changes its posture due to contact with the first support shaft  11   a , a load is less likely to be applied to the second spur gear  82  and the second internal gear  83 . 
     In the present exemplary embodiment, immediately before the cover  60  reaches the closed position C 0  from the open state, the second spur gear  82  is configured to escape to the outside of the second internal gear  83  such that the second spur gear  82  does not mesh with the second internal gear  83 , as illustrated in the state S 1  in  FIG. 5 . Therefore, in the present exemplary embodiment, locking of the second spur gear  82  can be prevented as compared to when the cover  60  reaches the closed position C 0  while the second spur gear  82  and the second internal gear  83  mesh with each other. 
     A resistance of the second damper  86  can be arbitrarily set, and the second damper  86  can also limit the rotational movement due to an empty weight of the cover  60 . In this case, the cover  60  can be held in any position between the state S 2  and the state S 3 . 
     Next, the operation of the buffer mechanism  70  of the front portion  60   f  illustrated in  FIG. 3  will be described. 
     The operation of the buffer mechanism  70  is almost the same as the operation of the buffer mechanism  80 . The rear portion  60   r  of the cover  60  is rotationally moved from the closed state in  FIG. 3  with respect to the front support portion  11  in the first direction R 1 , and the cover  60  is rotationally moved to the first open position C 1 , as illustrated in  FIG. 1 . 
     The state in  FIG. 3  is a state in which the first spur gear  72  and the first internal gear  73  do not mesh with each other, and the buffering mechanism  70  is not in operation. When the cover  60  starts to gradually rotationally move in the first direction R 1  from the closed state in  FIG. 3 , the first spur gear  72  and the first internal gear  73  start to mesh with each other, and the first damper  76  gradually starts to operate similarly to the operation of the buffering mechanism  80  described above. When the cover  60  reaches the first open position C 1 , which is the maximum rotational movement state to the front, the rotational movement of the cover  60  into the first direction R 1  is regulated by a stopper (not illustrated). 
     The rotational movement range G 1  is a range in which the first spur gear  72  does not contact the first internal gear  73 , and the first damper  76  does not operate. The rotational movement range G 2  is a range in which the first spur gear  72  contacts the first internal gear  73 , and the first damper  76  operates. In this way, in the buffer mechanism  70  of the front portion  60   f  of the cover  60 , the rotational movement range G 1  in which the first damper  76  does not operate and the rotational movement range G 2  in which the first damper  76  operates are also provided similarly to the buffering mechanism  80 . 
     In the present exemplary embodiment, immediately before the cover  60  reaches the closed position C 0  from the open state, the first spur gear  72  is configured to escape to the outside of the first internal gear  73  such that the first spur gear  72  does not mesh with the first internal gear  73 , as illustrated in  FIG. 3 . Therefore, in the present exemplary embodiment, locking of the first spur gear  72  can be prevented as compared to when the cover  60  reaches the closed position C 0  while the first spur gear  72  and the first internal gear  73  mesh with each other. 
     A resistance of the first damper  76  can be arbitrarily set, and the first damper  76  can also limit the rotational movement due to an empty weight of the cover  60 . 
       FIG. 6  illustrates a state in which roll paper  102  is loaded. The same portion as that in  FIG. 1  is denoted by the same reference sign, and description thereof will be omitted. 
     In the present exemplary embodiment, when the roll paper is loaded from the front of the printing apparatus  1 , the front portion  60   f  of the cover  60  is rotationally moved in the second direction R 2 , and the housing portion  21  is opened. The roll paper  102  is disposed in the opened housing portion  21 . One end of the disposed roll paper  102  is pulled out and loaded between the paper guide  33  and the paper holder  34 . Then, the sheet P is introduced into the printing unit  20 , and the cover  60  is closed. When work is conducted from the front of the printing apparatus  1 , the front portion  60   f  of the cover  60  is opened to the second open position C 2 , and thus a great work space close to the front of the printing apparatus  1  is secured. 
     In the present exemplary embodiment, the rear portion  60   r  of the cover  60  may be opened to the first open position C 1  illustrated in  FIG. 1 , and the roll paper  102  may be loaded from the rear of the printing apparatus  1 . 
     In the printing apparatus  1  according to the present exemplary embodiment, the front portion  60   f  or the rear portion  60   r  of the cover  60  is opened, and thus fanfold paper and roll paper can be loaded from the front and rear of the printing apparatus  1  along the transport direction F of the sheet P. Therefore, a degree of freedom in the arrangement of the printing apparatus  1  is less likely to be limited for loading work of the sheet P. 
     The printing apparatus  1  according to the exemplary embodiment to which the present disclosure is applied is the printing apparatus  1  including the printing unit  20  configured to perform printing on the sheet P being a recording medium. The printing apparatus  1  includes, in the printing apparatus main body  10 , the housing portion  21  configured to house the sheet P, the transport unit  30  configured to transport the sheet P from the housing portion  21  to the printing unit  20 , the cover  60  configured to open and close the housing portion  21 , and the first support shaft  11   a  and the second support shaft  12   a  configured to rotatably support the cover  60 . The first support shaft  11   a  is disposed in a position closer to the printing unit  20  than the housing portion  21 , and the second support shaft  12   a  is disposed in a position farther from the printing unit  20  than the housing portion  21 . When the cover  60  is displaced from the closed position C 0  in the first direction R 1 , the cover  60  is spaced from the second support shaft  12   a  and is rotationally movable around the first support shaft  11   a  to the first open position C 1 . When the cover  60  is displaced from the closed position C 0  in the second direction R 2 , the cover  60  is spaced from the first support shaft  11   a  and is rotationally movable around the second support shaft  12   a  to the second open position C 2 . 
     According to the printing apparatus  1  described above, the cover  60  can be opened and closed with the first support shaft  11   a  or the second support shaft  12   a  as a rotational movement center. Thus, work for housing and loading the sheet P can be performed from two directions with respect to the printing apparatus  1 . Further, how the cover  60  opens can be selected in accordance with a working space for housing and loading. In this way, the cover  60  is less likely to enter the working space during housing and loading, and the work for housing and loading the sheet P into the printing apparatus  1  can be easily performed. Since the mounting of the sheet P can be appropriately selected from the two directions, a degree of freedom in installation of the printing apparatus  1  is increased. Further, when a plurality of types of the sheet P are used, an optimal mounting method can be selected, and the usability of the printing apparatus  1  is improved. 
     In the printing apparatus  1  described above, the transport unit  30  is configured to transport, to the printing unit  20 , the fanfold paper  101  being an external recording medium supplied from the outside of the printing apparatus main body  10 , the cover  60  in the first open position C 1  forms, in the housing portion  21 , the opening through which the sheet P is insertable to the housing portion  21 , and also opens, at one end of the housing portion  21 , the insertion opening  71  that guides the fanfold paper  101  into the printing apparatus  1 , and the cover  60  in the second open position C 2  forms, in the housing portion  21 , the opening through which the sheet P and the fanfold paper  101  are loadable on the transport unit  30 . 
     According to the printing apparatus  1  described above, the fanfold paper  101  passes through the insertion opening  71  by closing the cover  60 , and thus the fanfold paper  101  can be easily loaded in the printing apparatus  1 . 
     Further, the printing apparatus  1  described above may further include the first engagement member  65  provided at the cover  60 , and configured to engage with the first support shaft  11   a  such that the cover  60  is rotationally movable from the closed position C 0  of the cover  60  to the first open position C 1 , and disengage from the first support shaft  11   a  by moving with respect to the first support shaft  11   a , and the second engagement member  68  provided at the cover  60 , and configured to engage with the second support shaft  12   a  such that the cover  60  is rotationally movable from the closed position C 0  of the cover  60  to the second open position C 2 , and disengage from the second support shaft  12   a  by moving with respect to the second support shaft  12   a.    
     According to the printing apparatus described above, the first engagement member  65  engages with the first support shaft  11   a  or the second engagement member  68  engages with the second support shaft  12   a  in the rotational movement state of the cover  60 . In this way, the behavior of the cover  60  is stabilized when the cover  60  is opened and closed. Then, work for housing and loading the sheet P accompanied by opening and closing of the cover  60  can be easily performed. The cover  60  can be stably held in the closed position C 0  while the cover  60  can be opened and closed in two directions. 
     The printing apparatus  1  described above may further include the first spur gear  72  provided at the cover  60 , and configured to mesh with the first internal gear  73  provided on the peripheral portion of the first support shaft  11   a  and rotate by the rotational movement of the cover  60  around the first support shaft  11   a , the first damper  76  configured to apply a load to rotation of the first spur gear  72 , the second spur gear  82  provided at the cover  60 , and configured to mesh with the second internal gear  83  provided on the peripheral portion of the second support shaft  12   a  and rotate by the rotational movement of the cover  60  around the second support shaft  12   a , and the second damper  86  configured to apply a load to rotation of the second spur gear  82 . 
     According to the printing apparatus described above, the first damper  76  and the second damper  86  can suppress sudden opening and closing of the cover  60 , and the behavior of the cover  60  is stabilized when the cover  60  is opened and closed. In this way, work for housing and loading the sheet P accompanied by opening and closing of the cover  60  can be easily performed. 
     In the printing apparatus  1  described above, the second support shaft  12   a  may be located in a direction opposite to the discharge direction of the sheet P with respect to the first support shaft  11   a.    
     According to the printing apparatus described above, the opening direction when the cover  60  rotationally moves around the first support shaft  11   a  is the discharge direction of the sheet P, and the opening direction when the cover rotationally moves around the second support shaft  12   a  is opposite to the discharge direction of the sheet P. In this way, the cover  60  opens along the movement direction of the sheet P, and work for housing and loading the sheet P can be easily performed. 
     Each of the exemplary embodiments described above merely represents one aspect of the present disclosure, and the specific aspects of the present disclosure and the scope of application of the present disclosure are not limited to the exemplary embodiments described above. In the exemplary embodiments described above, the cover  60  is described as a cover that covers the housing portion  21  housing the recording medium. However, the present disclosure is not limited thereto, and the present disclosure is applicable to a cover that covers a housing portion of an article other than the recording medium, for example, a housing portion of a consumable item such as recording paper and an ink cartridge.