Patent Publication Number: US-9884486-B2

Title: Printing apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority benefit of Japanese Patent Application No. 2015-100579, filed on May 15, 2015. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     TECHNICAL FIELD 
     The present disclosure relates to a printing apparatus. 
     RELATED ART 
     Printing apparatuses using inkjet heads jet ink from the inkjet heads onto media such as recording paper, thereby performing printing. However, in a case where ink is slowly dried, wet ink may be mixed, resulting in a decrease in chroma or blurring of images. Especially, in printing apparatuses, such as line printers, which eject ink in units of lines extending in a main scan direction while conveying media, since the amount of ink ejection relative to the medium conveyance speed is large, it is difficult for ink to be dried. For this reason, conventional printing apparatuses which positively dry ink ejected on media are described. 
     For example, an inkjet printer disclosed in JP-A-2001-334647 blows warm air to media after printing, thereby drying ink ejected on the media. However, warm air flows between an inkjet head and a medium, ink ejection positions on the medium may be deviated from predetermined positions, resulting in a degradation in the printing quality. In order to prevent this problem, in the above described inkjet printer, the warm-air blowing direction is set to the medium conveyance direction. 
     However, in a case of blowing warm air directly to a medium by a fan, so-called “cockling” which is a phenomenon that temperature on the medium becomes uneven, and this uneven temperature causes difference in drying time, whereby wrinkles are made in a wave shape in the medium may occur. Also, in the case of blowing warm air directly to a medium, since temperature management is likely to be insufficiently performed, cockling may be caused by drying failure attributable to deficiency in the amount of heat or excessive heating. Also, although it is preferable that the ink drying time should be very short, rapid drying which is performed by increasing the amount of warm air or raising the temperature of warm air, or uneven drying is likely to lead to occurrence of cockling. As described above, it has been very difficult to dry ink ejected on media without causing cockling. 
     SUMMARY 
     The present disclosure is made in view of the above described circumstances, and the present disclosure provides a printing apparatus capable of drying ink on media while suppressing cockling from occurring. 
     In order to solve the above described problems, a printing apparatus according to the present disclosure includes: a head that ejects an ink onto a recording medium; a driver that relatively moves positions of the head and the recording medium; a cover member that is positioned on a downstream side from the head in a movement direction of the recording medium relative to the head, so as to cover at least a portion of the recording medium; a drying-air-flow supply that sends a drying air flow for drying the ink ejected on the recording medium, into a gap between the recording medium and the cover member; and a heater that heats at least one of the drying air flow and a preliminary air which is a previous stage of the drying air flow, wherein a flow path changer is provided so as to change a flow direction of the preliminary air which is the previous stage of the drying air flow, at least once. 
     In this disclosure, since the flow direction of the preliminary air which is the previous stage of the drying air flow is changed by the flow path changer, and then the preliminary air is sent as the drying air flow toward the gap between the recording medium and the cover member, it is possible to suppress the preliminary air from straightly flowing. Therefore, it is possible to suppress an uneven air flow from being created on the recording medium, and it is possible to suppress cockling from occurring. As a result, it is possible to dry the ink on the recording medium while suppressing cockling from occurring. Also, since at least one of the air from the air blower and the cover member is heated by the heater, and an air flow with little unevenness is used to raise the temperature of the drying air flow for drying the ink, it is possible to easily perform temperature management during drying of the ink. 
     Also, in the above described printing apparatus, the drying-air-flow supply may be an air blower for blowing the preliminary air, and the flow path changer may be an air-flow-direction changing wall part configured such that the preliminary air blown from the air blower collides with the air-flow-direction changing wall part, whereby the flow direction of the preliminary air is changed. 
     In this disclosure, since the air blower blows the preliminary air, whereby the preliminary air collides with the air-flow-direction changing wall part, whereby the flow direction is changed such that the preliminary air is used as the drying air flow, it is possible to easily create the drying air flow to flow toward the gap between the recording medium and the cover member. As a result, it is possible to easily dry the ink on the recording medium. 
     Also, in the above described printing apparatus, a widening duct in fan shape that spreads the preliminary air blown by the air blower, in a direction perpendicular to the movement direction of the recording medium may be disposed, and in the widening duct, near a leading end portion in an air blowing direction, a plurality of current plates extending in the flow direction of the preliminary air blown from the air blower may be provided in a line in a width direction. 
     In this disclosure, since the plurality of current plates is disposed inside the widening duct, it is possible to evenly send air out from an opening of the widening duct, and it is possible to evenly send air into an air flow path. As a result, the volume of air flow is uniformized, and it is possible to suppress unevenness in heating which is performed by the heater, and it is possible to suppress the ink from being unevenly dried. 
     Also, in the above described printing apparatus, the flow path changer may be an air blower for blowing the preliminary air positioned on an opposite side of the cover member to the recording medium, into the gap between the recording medium and the cover member. 
     In this disclosure, since the preliminary air positioned on the opposite side of the cover member to the recording medium is blown into the gap between the recording medium and the cover member by the air blower, it is possible to use the preliminary air as the drying air flow by changing the flow direction of the preliminary air. Therefore, it is possible to easily send the drying air flow toward the gap between the recording medium and the cover member, and it is possible to easily dry the ink on the recording medium by the drying air flow. 
     Also, in the above described printing apparatus, the flow path changer may be an air breather for sucking the drying air flow. 
     In this disclosure, since the drying air flow between the recording medium and the cover member is sucked by the air breather, it is possible to produce a negative pressure in the gap between the recording medium and the cover member, and this negative pressure causes the flow direction of the preliminary air positioned on the opposite side of the cover member to the recording medium to change such that the preliminary air flows into the gap between the recording medium and the cover member. Therefore, it is possible to easily send the drying air flow toward the gap between the recording medium and the cover member, and it is possible to easily dry the ink on the recording medium by the drying air flow. 
     Also, in the above described printing apparatus, the flow path changer may change the flow direction of the preliminary air such that the preliminary air flows toward a lower side in the gap between the recording medium and the cover member. 
     In this disclosure, since the preliminary air blown from the air blower is sent downward, thereby flowing as the drying air flow toward the gap between the recording medium and the cover member, in a case where air is heated by the heater, thereby flowing upward, it is possible to direct the flow of air downward. As a result, it is possible to make warm air stay between the cover member and the recording medium, and it is possible to improve drying efficiency. Also, since air blown from the air blower is directed downward, it is possible to make it difficult for heat generated by the heater to be transferred to the head. Therefore, it is possible to reduce adverse effects such as poor ink ejection attributable to drying of nozzles. 
     Also, in the above described printing apparatus, the heater may comprise a cord type heater, and be bonded to the cover member, and the heater may heat the cover member, thereby heating the drying air flow. 
     In this disclosure, since the heater heats the cover member, thereby heating the drying air flow in the air flow path, it is possible to perform temperature management by detecting the temperature of the cover member, and it is possible to improve the reliability of temperature management. Also, in a case of heating the drying air flow in the air flow path, the cover member is also heated. Therefore, it is possible to improve heating efficiency during heating of the drying air flow. Also, since the inexpensive cord type heater is used as the heater, it is possible to suppress the manufacturing cost. Further, since the cord type heater is bonded to the cover member, it is possible to thin a cover for covering the cord type heater, and it is possible to make the whole apparatus compact. 
     Also, in the above described printing apparatus, the cord type heater may be disposed throughout a width direction of the recording medium in a direction perpendicular to the movement direction of the recording medium. 
     In this disclosure, since the cord type heater is provided throughout the width direction of the recording medium in the main scan direction, it is possible to suppress a reduction in temperature at joints of heaters. In other words, for example, unlike in a case of using glass tube heaters or sheath heaters as the heater, it is possible to suppress a reduction in temperature at joints. As a result, it is possible to more surely and evenly heat air in the air flow path. 
     Also, in the above described printing apparatus, after the flow direction of all of the preliminary air is changed by the flow path changer, the preliminary air may be used as the drying air flow. 
     In this disclosure, after the flow direction of all of the preliminary air is changed by the air-flow-direction changing wall part, whereby unevenness of the air flow is reduced, the preliminary air is sent as the drying air flow into the gap between the recording medium and the cover member. Therefore, it is possible to suppress a drying air flow having been unevenly heated from coming into contact with the recording medium. As a result, it is possible to more surely suppress cockling attributable to uneven drying or a variation in temperature. 
     Also, in the above described printing apparatus, between the head and an air outlet from which an air is sent out after the flow direction of the air is changed by the flow path changer, a partition plate may be disposed to separate the air outlet and the head. 
     In this disclosure, since the partition plate is provided between the air outlet and the head, it is possible to suppress a flow of heated air from reaching the head, thereby suppressing the heated air from drying ink on ejection ports of the head. As a result, printing failures are prevented from being caused by drying of ink on the ejection ports of the head, and it is possible to dry ink on the recording medium. 
     Also, in the above described printing apparatus, the cover member may include: a first cover part, and a second cover part which is positioned on the downstream side from the first cover part in the movement direction of the recording medium, and on the cover member, a rotator which rotates on a rotating shaft extending in a direction perpendicular to the movement direction of the recording medium may be connected, and the first cover part and the second cover part may be connected by the rotator so as to be rotatable with respect to each other. 
     In this disclosure, since the first cover part and the second cover part are connected so as to be able to relatively rotate, it is possible to fold the first cover part and the second cover part on the occasion of setting a recording medium, and to unfold the first cover part and the second cover part on the occasion of starting printing. As a result, it is possible to suppress ease of setting of a recording medium from being damaged, and provide the cover member at a position facing a recording medium. Also, even in a case where a recording medium is jammed, or a trouble occurs in the heater or the like, if necessary, it is possible to unfold and fold the first cover part and the second cover part, whereby it is possible to easily handle those troubles. As a result, it is possible to improve maintainability. 
     Also, the above described printing apparatus may further include: an after-platen that supports a portion of the recording medium positioned on the downstream side from the head in the movement direction of the recording medium relative to the head; and a recording-medium heater that is disposed on the after-platen, and heats the recording medium, wherein the recording-medium heater is configured such that a downstream area in the movement direction of the recording medium heats the recording medium at a higher temperature as compared to an upstream area. 
     In this disclosure, when ink ejected on the recording medium is dried by the recording-medium heater, the upstream area in the movement direction of the recording medium serves as a buffer zone, whereby it is possible to suppress sudden drying. As a result, it is possible to suppress cockling from occurring. 
     Also, the above described printing apparatus may further include: recording medium members that regulate movement of the recording medium in a width direction and a thickness direction of the recording medium, wherein, in the movement direction of the recording medium relative to the head, the recording medium members are disposed in an area where the head ejects the ink onto the recording medium. 
     In this disclosure, since it is possible to regulate movement of a recording medium in the width direction and the thickness direction of the recording medium by the recording medium members when the head ejects the ink onto the recording medium, it is possible to suppress cockling from occurring. 
     Also, the above described printing apparatus may further include: an after-platen that supports a portion of the recording medium positioned on the downstream side from the head in the movement direction of the recording medium relative to the head; a recording-medium heater that is disposed on the after-platen, and heats the recording medium; and recording medium members that regulate movement of the recording medium in a width direction and a thickness direction of the recording medium, wherein, in the movement direction of the recording medium relative to the head, the recording medium members are disposed throughout an area where the head ejects the ink onto the recording medium and a position of an upstream end of an area where the recording-medium heater is disposed. 
     In this disclosure, in a state where ink ejected on the recording medium is wet, it is possible to hold the recording medium by the recording medium members. In this way, while being held by the recording medium members, the recording medium moves to the area where the recording-medium heater is disposed. Therefore, after a predetermined time from ink ejection, it is possible to dry ink in the area where the recording-medium heater is disposed. Therefore, it becomes difficult for a recording medium to be suddenly deformed, and it is possible to effectively suppress cockling from occurring. 
     Also, a printing apparatus according to the present disclosure includes: a head that ejects an ink onto a recording medium; a driver that relatively moves the positions of the head and the recording medium; a platen for mounting the recording medium; a cover member that is positioned on a downstream side from the head in a movement direction of the recording medium relative to the head, so as to cover at least a portion of the recording medium; a drying-air-flow supply that sends a drying air flow for drying the ink ejected on the recording medium, into a gap between the recording medium and the cover member; and a heater that heats at least one of the drying air flow and a preliminary air which is a previous stage of the drying air flow, wherein the cover member is a boxed member formed in a box shape and having an internal space filled with air, and the boxed member contains the heater and the drying-air-flow supply. 
     In this disclosure, since the heater and the drying-air-flow supply are stored inside the boxed member formed as the cover member, it is possible to improve heating efficiency due to heat insulating effect while saving space. Therefore, it is possible to evenly heat the space between the cover member and the recording medium, and it is possible to suppress temperature unevenness. As a result, it is possible to dry ink on the recording medium while suppressing cockling from occurring. 
     Also, in the above described printing apparatus, the drying-air-flow supply may be disposed on an opposite side of the heater to the platen. 
     In this disclosure, since the drying-air-flow supply is disposed at a position on the opposite side of the heater to the platen, so as to overlap the heater, it is possible to suppress the drying-air-flow supply from protruding outward from the heater disposition area where the heater is disposed, thereby suppressing the drying-air-flow supply from occupying a large space. As a result, it is possible to save space. 
     Also, in the above described printing apparatus, the cover member may be formed in long shape along the platen in a direction of gravity, and an opening for sending out the drying air flow or the preliminary air may be formed at a top of the boxed member in the direction of gravity, and the drying air flow or the preliminary air may be sent from the opening by the drying-air-flow supply, whereby the drying air flow is introduced into the gap between the platen and the cover member. 
     In this disclosure, since the drying air flow or the preliminary air is sent from the opening formed at the top of the boxed member, it is possible to suppress the heated drying air flow positioned between the platen and the cover member from exiting from the upper side in the direction of gravity. As a result, it is possible to further improve heating efficiency. 
     The printing apparatus according to the present disclosure has an effect that it is possible to dry ink on media while suppressing cockling from occurring. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a printing apparatus according to an embodiment. 
         FIG. 2  is a schematic view illustrating the configuration of the printing apparatus shown in  FIG. 1 . 
         FIG. 3  is a perspective view of a dryer shown in  FIG. 1 . 
         FIG. 4  is a cross-sectional view as the dryer shown in  FIG. 3  is seen in a main scan direction. 
         FIG. 5  is a perspective view illustrating the dryer shown in  FIG. 3  without heating element covers. 
         FIG. 6  is a perspective view of a widening duct shown in  FIG. 5 . 
         FIG. 7  is a plan view of a cover member shown in  FIG. 4 . 
         FIG. 8  is a perspective view illustrating the state of the dryer when the printing apparatus performs printing. 
         FIG. 9  is a perspective view illustrating the dryer in a case of folding the dryer shown in  FIG. 8 . 
         FIG. 10  is a perspective view illustrating the dryer shown in  FIG. 9  in a state where the dryer is folded. 
         FIG. 11  is a perspective view illustrating the printing apparatus in a state where the dryer is folded. 
         FIG. 12  is a view for explaining a case of using air blowing fans as flow path changer, as a modification of the printing apparatus according to the embodiment. 
         FIG. 13  is a view for explaining a case of using air intake fans as flow path changer, as another modification of the printing apparatus according to the embodiment. 
         FIG. 14  is a view for explaining a cord type heater which is provided in an after-platen, as another modification of the printing apparatus according to the embodiment. 
         FIG. 15  is a detailed view of a portion including the after-platen shown in  FIG. 14 . 
         FIG. 16  is a view as seen in a direction shown by arrows C-C of  FIG. 15 . 
         FIG. 17  is a view as seen in a direction shown by arrows A-A of  FIG. 14 . 
         FIG. 18  is a view as seen in a direction shown by arrows B-B of  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of a printing apparatus according to the present disclosure will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited by the embodiment. Also, in components of the following embodiment, ones with which person skilled in the art can easily substitute the components, and ones which are substantially identical to the components are included. 
     Embodiment 
       FIG. 1  is a perspective view of a printing apparatus of an embodiment. FIG.  2  is a schematic view illustrating the configuration of the printing apparatus shown in  FIG. 1 . A printing apparatus  1  according to the present embodiment is configured by assembling a dryer  20  with a printing apparatus main body  2 , and the printing apparatus main body  2  includes: a head  4 , a platen  7 , and a driver  10 . The printing apparatus main body  2  is supported by legs  3 , which are placed at desired positions on the ground, whereby the printing apparatus main body  2  is installed at an arbitrary installation position. The head  4  included in the printing apparatus main body  2  is configured to be able to eject ink onto a medium  100  which is a recording medium when performing printing on the medium  100 . The head  4  is configured to be able to eject ink while moving along a Y bar  5  extending in one direction, and the movement direction of the head  4  is a main scan direction (a Y direction in the drawings) when the printing apparatus  1  performs printing. 
     Also, the platen  7  is composed of a mounting table for mounting the medium  100  on the occasion of ejecting ink onto the medium  100 . The head  4  is disposed above the platen  7 , so as to be able to eject ink onto the medium  100  from the above of the medium  100  mounted on the platen  7 . 
     Also, the driver  10  is configured so as to be able to relatively move the positions of the head  4  and the medium  100 . Since the medium  100  is wound like a roll in advance by a medium feeding roller  13  for winding a medium  100  before printing, when the printing apparatus  1  performs printing, the driver  10  relatively moves the medium  100  with respect to the head  4  while drawing the medium wounded around the medium feeding roller  13 . The direction in which the driver  10  moves the medium  100  with respect to the head  4  is a sub scan direction (an X direction in the drawings) which is a direction perpendicular to both of the main scan direction and an up and down direction (a Z direction in the drawings) in the normal use mode of the printing apparatus  1 . 
     The driver  10  which moves the medium  100  in the sub scan direction includes: a drive roller  11  which draws the medium  100  from the medium feeding roller  13  and conveys the medium  100  to a side of the head  4 , and a winding roller  12  which winds the medium  100  after ink is ejected from the head  4 . All of the drive roller  11 , the winding roller  12 , and the medium feeding roller  13  are composed of rollers having rotating shafts which are disposed in the main scan direction. Also, the medium feeding roller  13  and the winding roller  12  are disposed below the platen  7 . Therefore, the medium  100  is disposed from the lower side toward the upper side over an area from the medium feeding roller  13  to the platen  7 , and is disposed from the upper side toward the lower side over an area from the platen  7  to the winding roller  12 . 
     Both of the drive roller  11  and the winding roller  12  included in the driver  10  are configured to be able to receive power from an electric motor (not shown) which is a power source, and be rotatable by power transmitted from the electric motor. Their rotation directions are directions making it possible to convey the medium  100  from the drive roller  11  to the winding roller  12  through the gap between the head  4  and the platen  7 , and the rotation speed of the winding roller  12  is higher than the rotation speed of the drive roller  11 . 
     Also, the drive roller  11  is configured to be able to rotate on the rotating shaft while bringing the outer circumferential surface into contact with the medium  100 , thereby conveying the medium  100  being in contact with the outer circumferential surface to the side of the head  4 . As described above, at a position where the outer circumferential surface of the drive roller  11  comes into contact with the medium  100 , on the opposite side of the medium  100  to the side which comes into contact with the outer circumferential surface of the drive roller  11 , a driven roller  14  is disposed such that its outer circumferential surface comes into contact with the medium  100 , similarly to the drive roller  11 . In other words, the medium  100  is threaded from the medium feeding roller  13  toward the gap between the head  4  and the platen  7  through the gap between the drive roller  11  and the driven roller  14 . While the driven roller  14  rotates according to movement of the medium  100  attributable to rotation of the drive roller  11 , it comes into contact with the medium  100 , thereby applying a biasing force in a direction for pressing the medium  100  against the drive roller  11 . 
     The winding roller  12  is positioned on the downstream side from the platen  7  in the movement direction of the medium  100  which is moved by the driver  10 , that is, the conveyance direction of the medium  100 , and is configured to be able to wind the medium  100  which is fed by the drive roller  11 . 
     Between the winding roller  12  and the platen  7 , a positioning roller  15  is provided so as to apply a biasing force to the medium  100 , thereby tensioning a portion of the medium  100  which is positioned between the positioning roller  15  and the platen  7 . At a position on the downstream side from the platen  7  in the conveyance direction of the medium  100 , the positioning roller  15  comes into contact with, for example, a surface of the medium  100  on the side being in contact with the platen  7 , thereby applying the biasing force to the medium  100 . Since the winding roller  12  is disposed on the downstream side from the positioning roller  15  in the conveyance direction of the medium  100 , in an area which is positioned on the downstream side from the platen  7  in the conveyance direction of the medium  100 , the upstream side and downstream side of the positioning roller  15  differ in the conveyance direction. The path which starts from the medium feeding roller  13 , passes through the gap between the drive roller  11  and the driven roller  14 , passes the top of the platen  7 , and leads to the winding roller  12  through the positioning roller  15  is a conveyance path  8  which is a path in which the medium  100  is conveyed. 
     The dryer  20  included in the printing apparatus  1  according to the present embodiment is disposed on the downstream side from an area where the head  4  is disposed, in the conveyance direction of the medium  100 , so as to face the surface of the medium  100  to which ink ejected from the head  4  attaches. More specifically, the dryer  20  is disposed so as to face a portion of the medium  100  which is positioned between the head  4  and the positioning roller  15  in the conveyance direction of the medium  100 . In other words, the dryer  20  is disposed so as to face a portion of the medium  100  disposed from the upper side toward the lower side in a portion of the conveyance path from the platen  7  toward the positioning roller  15  and the winding roller  12 . Also, the width of the dryer  20  in the main scan direction is set to a width larger than the width of the medium  100  in the main scan direction. 
     The dryer  20  includes: a first heating element  21 , and a second heating element  22  which is disposed below the first heating element  21 . In other words, the second heating element  22  is disposed on the downstream side from the first heating element  21  in the conveyance direction of the medium  100 . Both of the first heating element  21  and the second heating element  22  are composed of boxy members formed in box shapes and having internal spaces filled with air. The first heating element  21  and the second heating element  22  are formed so as to extend in the main scan direction, and are connected to each other by a hinge  23  which is a rotator which rotates on a rotating shaft extending in the main scan direction of the head  4 . The hinge  23  is connected to a lower end portion of the first heating element  21  and an upper end portion of the second heating element  22 , whereby the first heating element  21  and the second heating element  22  become able to relatively rotate on the rotating shaft of the hinge  23 . Since the first heating element  21  and the second heating element  22  become able to relatively rotate by the hinge  23  as described above, the dryer  20  becomes able to expand and contract in a direction along the conveyance path  8 . 
     The first heating element  21  and the second heating element  22  have cover members  25  on their sides facing the medium  100 . The cover members  25  include: a first cover part  26 , and a second cover part  27  which is positioned on the downstream side from the first cover part  26  in the movement direction of the medium  100 , and are positioned on the downstream side from the head  4  in the movement direction of the medium  100  relative to the head  4 , so as to cover at least a portion of the medium  100 . Of them, the first cover part  26  constitutes the first heating element  21 , and the second cover part  27  constitutes the second heating element  22 . The first cover part  26  and the second cover part  27 , that is, the first heating element  21  and the second heating element  22  are formed in long shape in the direction of gravity along the platen  7 . The cover members  25  are formed so as to cover at least a portion of the conveyance path  8  for conveying the medium  100 , and the cover members  25  are configured such that at least a part of the portion covering the conveyance path  8  can expand and contract according to relative rotation of the first heating element  21  and the second heating element  22 . 
     Specifically, the first cover part  26  is provided on a face of the first heating element  21  facing the medium  100 , and the second cover part  27  is provided on a face of the second heating element  22  facing the medium  100 . Both of the first cover part  26  and the second cover part  27  are formed by sheet-metal members, and are turned such that their plate thickness directions become close to the thickness direction of the medium  100 , and are disposed so as to face the medium  100 . Since the cover members  25  which are provided as described above are provided on the first heating element  21  and the second heating element  22  to which the hinge  23  is connected, it can be said that the hinge  23  is connected to the cover members  25 . In this way, the first cover part  26  and the second cover part  27  are connected by the hinge  23  disposed therebetween, so as to be able to relatively rotate with respect to each other, and at least one of them is configured to be able to retreat from a position for covering the conveyance path  8  by relatively rotating by the hinge  23 . 
     Also, in the first heating element  21 , air blowers  40  are provided so as to blow air to a space between the dryer  20  and the medium  100 , and the air blowers  40  are stored in the first heating element  21 . Each air blower  40  has an air outlet  61  formed in a surface facing the medium  100 , that is, a surface facing the platen  7 , and can blow air from the air outlet  61  to the space between the dryer  20  and the medium  100 . The air outlet  61  of each air blower  40  is formed in the vicinity of the upper end of a surface of the dryer  20  facing the medium  100 . Specifically, the air outlets  61  are formed at the top of the first heating element  21  in the direction of gravity, and are openings for blowing a drying air flow Fd (see  FIG. 4 ) or preliminary air Ap (see  FIG. 4 ) by air blowing fans  45  such that the drying air flow Fd is introduced into the gap between the platen  7  and the cover members  25 . 
     The air blowers  40  which are formed as described above include: the air blowing fans  45  which are air blowers, and air-flow-direction changing wall parts  60  which are provided on the air flow path of the air blowing fans  45  and change the flow direction of air blown from the air blowing fans  45 . Of them, the air blowing fans  45  are provided as drying-air-flow supply which cause the drying air flow Fd (see  FIG. 4 ) for drying ink ejected on the medium  100  to flow between the medium  100  and the cover members  25 . If electric power is supplied to the air blowing fans  45 , the air blowing fans become able to operate to create wind inside the air blowers  40 , thereby blowing the preliminary air Ap (see  FIG. 4 ) which is the previous stage of the drying air flow Fd. 
     Also, the air-flow-direction changing wall parts  60  are provided as flow path changer for changing the flow direction of the preliminary air Ap which is the previous stage of the drying air flow Fd. Specifically, the air-flow-direction changing wall parts  60  are provided above the air blowing fans  45 , such that the preliminary air Ap blown from the air blowing fans  45  can collide with the air-flow-direction changing wall parts  60 , whereby the flow direction can be changed. In this way, the air-flow-direction changing wall parts  60  can change the flow direction of the preliminary air Ap blown upward from the air blowing fans  45 , thereby directing the wind toward the air outlets  61 . In other words, the air-flow-direction changing wall parts  60  direct air blown from the air blowing fans  45  downward, thereby directing the wind created in the air blowers  40  toward the air outlets  61 , and send the wind out from the air outlets  61 , thereby sending the wind as the drying air flow Fd toward the gap between the medium  100  and the cover members  25 . 
     Also, in the dryer  20 , at least one cord type heater  28  is provided as heater for heating air blown from the air blowing fans  45  or/and the cover members  25 . The cord type heaters  28  are bonded to the opposite surfaces of the cover members  25  to their surfaces facing the medium  100 , and are bonded to both of the first cover part  26  and the second cover part  27 . The cord type heaters  28  which are bonded to the cover members  25  as described above can heat the cover members  25 , thereby heating the drying air flow Fd blown toward the gap between the medium  100  and the cover members  25  by the air blowers  40 . 
     In the printing apparatus  1 , between the air outlets  61  which are formed at the dryer  20  and the head  4  which is provided in the printing apparatus main body  2 , a partition plate  18  is provided to separate the air outlets  61  and the head  4 . The partition plate  18  is provided in the printing apparatus main body  2  so as to be positioned above the platen  7  and on the downstream side from the head  4  in the conveyance direction of the medium  100 . When the medium  100  is mounted on the platen  7  and is conveyed from the side of the head  4  to the side where the positioning roller  15  and the winding roller  12  are positioned, the medium is conveyed through the gap between the partition plate  18  and the platen  7 . 
       FIG. 3  is a perspective view of the dryer shown in  FIG. 1 .  FIG. 4  is a cross-sectional view as the dryer shown in  FIG. 3  is seen in the main scan direction. The dryer  20  is assembled with the printing apparatus main body  2  by fixing members  75  which are disposed on both ends of the dryer  20  in the main scan direction. The fixing members  75  are provided on two portions on both sides of the dryer  20  in the main scan direction, and extend from both end portions of the dryer  20  toward the side where the printing apparatus main body  2  is positioned, as seen from the dryer  20 . 
     In the dryer  20 , at both end portions of the second heating element  22  in the main scan direction, rotation connection parts  24  are provided so as to be close to the lower end of the second heating element  22 . The rotation connection parts are connected to the fixing members  75 , so as to be rotatable. Since the rotation connection parts  24  are formed so as to protrude in the main scan direction, the second heating element  22  connected to the fixing members  75  by the rotation connection parts  24  is rotatable on the axial center of the rotation connection parts  24  extending in the main scan direction. 
     Also, on the portions of the fixing members  75  which are connected to the rotation connection parts  24 , side plates  70  are attached. Like the fixing members  75 , the side plates  70  are provided at two portions on both sides of the dryer  20  in the main scan direction. On the first heating element  21 , engagement members  73  are provided so as to be close to the upper ends of both end portions of the first heating element  21  in the main scan direction and protrude in the main scan direction, and in the side plates  70 , folding/unfolding guides  71  for inserting the engagement members  73  are formed. The folding/unfolding guides  71  are formed, in a slit shape, as guide parts for guiding the engagement members  73 , thereby guiding the first heating element  21  during rotation, when the first heating element  21  relatively rotates with respect to the second heating element  22  by the hinge  23 . 
     Also, the first heating element  21  and the second heating element  22  have heating element covers  30  as their covers. The heating element covers  30  are provided on the opposite faces of the first heating element  21  and the second heating element  22  to their faces where the cover members  25  are provided. Specifically, on the first heating element  21 , a first heating element cover  31  is provided as a heating element cover  30 , and on the second heating element  22 , a second heating element cover  32  is provided as a heating element cover  30 . 
     The first heating element cover  31  and the second heating element cover  32  are formed so as to cover the opposite faces of the first heating element  21  and the second heating element  22  to their faces where the cover members  25  are provided, respectively. On the first heating element cover  31  of the first heating element cover  31  and the second heating element cover  32 , handles  35  are provided such that a user of the printing apparatus  1  can hold them to rotate the first heating element  21  and the second heating element  22 . The handles  35  are provided at two portions positioned on the upper half of the first heating element cover  31 , and the two handles  35  are provided almost in an inverted V shape so as to be symmetric with respect to the center of the first heating element cover  31  in the main scan direction. In other words, the two handles  35  are positioned such that the user can easily hold them with both hands. 
     Also, the air blower  40  are disposed inside the first heating element cover  31 , so as to be close to the upper end of the inside of a space which is defined by the first heating element cover  31  and the first cover part  26 . The upper end portion of the first heating element cover  31  is provided as the air-flow-direction changing wall parts  60 . Between the air blowing fans  45  and the air-flow-direction changing wall parts  60 , widening ducts  50  and current plates  55  (to be described below) are provided. 
     Also, the upper end portion of the first heating element cover  31  is formed to be curved to the side where the first cover part  26  is positioned and be closer to the platen  7  than the first cover part  26  is. Therefore, on a face of the first heating element  21  on a side of the first cover part  26 , between the first cover part  26  and a portion of the first heating element cover  31  closer to the platen  7  than the first cover part  26  is, a gap is formed. This gap is formed as the air outlets  61 . Since the air outlets  61  are formed by the first cover part  26  and a portion of the first heating element cover  31  near its upper end as described above, the air outlets  61  are open substantially downward, and connect the inside and outside of the first heating element  21 . 
     In the dryer  20  having the air outlets  61  formed on the face positioned on a side of the platen  7  as described above, a space which is defined by the platen  7  and a face of the dryer where the cover members  25  are positioned is formed as an air flow path  90  of a wind sent out from the air outlets  61 . 
       FIG. 5  is a perspective view illustrating the dryer shown in  FIG. 3  without the heating element covers. Inside the first heating element  21  and the second heating element  22 , at portions closer to the heating element covers  30  than to the cover members  25 , heat insulating materials  38  are disposed. The heat insulating materials  38  are formed such that heat conductivity becomes low, and are disposed inside the first heating element  21  and the second heating element  22  so as to cover the whole cover members  25 . 
     Also, the plurality of air blower  40  is provided in a line in the main scan direction inside the first heating element  21 , and each air blower  40  includes an air blowing fan  45  and a widening duct  50 . Each widening duct  50  is formed in a fan shape for spreading the preliminary air Ap, blown from the air blowing fan  45 , in a direction perpendicular to the movement direction of the medium  100 , that is, the main scan direction. Specifically, an air blowing fan  45  is attached to each widening duct  50 , and each widening duct  50  is formed in a fan shape which widens in the main scan direction as it goes from a position where the air blowing fan  45  is disposed toward the upper end side of the first heating element  21 . Since each widening duct  50  is formed in a fan shape as described, the plurality of widening ducts  50  are disposed inside the first heating element  21  so as to be continuous in the main scan direction. 
       FIG. 6  is a perspective view of a widening duct shown in  FIG. 5 . The widening duct  50  is formed by assembling a fan side member  51  to be positioned on a side of the first heating element cover  31  and an air outlet side member  52  to be positioned on a side of the first cover part  26 . The fan side member  51  and the air outlet side member  52  are formed in fan shapes or trapezoidal shapes, and their shapes as they are seen substantially in the sub scan direction are similar to each other. The fan side member  51  and the air outlet side member  52  are assembled, whereby the widening duct  50  is formed so as to have an internal space. Also, at both ends of a portion of the widening duct  50  widening in the main scan direction, inclined surfaces  53  are provided so as to stand in the thickness direction of the first heating element  21 , and the internal space of the widening duct  50  is closed with respect to the main scan direction by the inclined surfaces. 
     Meanwhile, as for the heights of the trapezoidal shapes which are the shapes of the fan side member  51  and the air outlet side member  52 , the height of the air outlet side member  52  is lower than the height of the fan side member  51 . Also, in an end portion of the fan side member  51  on the wider side of the widening duct  50 , a wall surface is formed so as to stand in the thickness direction of the first heating element  21 . A portion which is defined by an end portion of the air outlet side member  52  on the wider side and a wall surface provided at the end portion on the wider side of the fan side member  51  so as to stand in the thickness direction of the first heating element  21  becomes a widening-duct opening  54  which is an opening of the widening duct  50 . The internal space of the widening duct  50  is connected to the outside of the widening duct  50  through the widening-duct opening  54 . The widening duct  50  is attached to the first heating element  21 , such that the widening-duct opening  54  is positioned in the vicinity of the air outlet  61  and the widening-duct opening  54  and the air outlet  61  are connected. An air blowing fan  45  is attached to the fan side member  51  so as to be able to blow air to the internal space of the widening duct  50 . 
     Also, the wall surfaces provided at the end portions of the fan side members  51  of the widening ducts  50  on the wider side so as to stand in the thickness direction of the first heating element  21 , and the upper end portion of the first heating element cover  31  constitute the air-flow-direction changing wall parts  60 . To this end, the widening-duct openings  54  are formed adjacent to the air-flow-direction changing wall parts  60 . 
     Inside each widening duct  50  which is formed as described above, in the vicinity of the wider end portion, that is, in the vicinity of the widening-duct opening  54 , a plurality of current plates  55  extending in the flow direction of the preliminary air Ap blown from the air blowing fan  45  is provided side by side in the width direction. The current plates  55  are provided over a portion between the fan side member  51  and the air outlet side member  52  such that the thickness direction is aligned with the widening direction of the widening duct  50  and the width direction is aligned with the height direction of the trapezoidal shapes which are the shapes of the fan side member  51  and the air outlet side member  52 . 
       FIG. 7  is a plan view of a cover member shown in  FIG. 4 . The cord type heaters  28  which are bonded to the cover members  25  are provided throughout the width direction of the medium  100  in the direction perpendicular to the movement direction of the medium  100 . Specifically, the cord type heaters  28  are disposed along the main scan direction on the cover members  25  and are turned in the vicinities of the end portions of the cover members  25  in the main scan direction, such that portions along the main scan direction are disposed in parallel in an up and down direction. In this way, the cord type heaters  28  are disposed over the entire areas of the cover members  25 , that is, the cord type heaters  28  are disposed over the entire areas of both of the first cover part  26  and the second cover part  27 . Therefore, the cord type heaters  28  are stored in the first heating element  21  and the second heating element  22 . Also, the air blower  40  which are stored in the first heating element  21  are disposed on the opposite side of the cord type heater  28  to the platen  7  so as to overlap the cord type heater  28 . 
     The dryer  20  and the printing apparatus main body  2  which are configured as described above are controlled by a control unit (not shown) which is provided in the printing apparatus main body  2 . The control unit is a unit for controlling each unit of the printing apparatus  1 , and includes a central processing unit (CPU) which functions as a controller for performing various processes, a random access memory (RAM) and a read only memory (ROM) for storing a variety of information, and so on. The control unit performs control on printing of the printing apparatus main body  2  on the medium  100  and an operation of the dryer  20  for drying the printed medium  100 . 
     The printing apparatus  1  according to the present embodiment is configured as described above, and the effects of the printing apparatus will be described below. On the occasion of performing printing on the medium  100 , the medium  100  wound around the medium feeding roller  13  like a roll is drawn from the medium feeding roller  13 , and passes through the gap between the head  4  and the platen  7 . In a state where the medium  100  has been disposed between the medium feeding roller  13  and the winding roller  12 , the printing apparatus  1  performs printing. 
       FIG. 8  is a perspective view illustrating the state of the dryer when the printing apparatus performs printing. Also, on the occasion of performing printing using the printing apparatus  1 , the dryer  20  in which the first heating element  21  and the second heating element  22  can relatively rotate is controlled, such that the first heating element  21  and the second heating element  22  are unfolded, whereby the cover members  25  of them face the medium  100 . Specifically, the engagement members  73  provided on the first heating element  21  are positioned at engagement portions  72  which are positions in the folding/unfolding guides  71  formed in the side plates  70  and where the engagement members  73  are inserted to unfold the first heating element  21  and the second heating element  22 . As a result, the dryer  20  becomes a state where the first heating element  21  and the second heating element  22  are unfolded and the first cover part  26  and the second cover part  27  face the medium  100 . 
     The printing apparatus  1  performs printing on the medium  100  by ejecting ink from the head  4  onto the medium  100 . At this time, the control unit moves the head  4  along the Y bar  5 , thereby moving the head  4  back and forth in the main scan direction. Therefore, the head  4  ejects ink onto the medium  100  placed on the platen  7  while reciprocating in the main scan direction, such that the ink lands on the medium  100 , thereby performing printing on the medium  100 . 
     After printing is performed on a predetermined range in the main scan direction by the head  4 , the control unit controls the driver  10 , thereby operating the drive roller  11  and the winding roller  12  to move the medium  100  from a side of the medium feeding roller  13  toward a side of the winding roller  12  by a predetermined movement amount. In other words, the control unit performs control such that the medium  100  moves with respect to the head  4  in the sub scan direction by the predetermined movement amount. After the medium  100  moves, the control unit re-performs control such that the head  4  is moved in the main scan direction while ink is ejected from the head  4 , whereby printing is performed on the predetermined range in the main scan direction. The printing apparatus  1  repeats the above described operation, thereby performing printing on the medium  100 . 
     Since the printing apparatus  1  performs printing while conveying the medium  100  in the sub scan direction as described above, the medium  100  after landing of ink is conveyed to a position facing the dryer  20 . During printing of the printing apparatus  1 , in the dryer  20 , while the cord type heaters  28  generate heat, the air blowing fans  45  create wind by the preliminary air Ap. In the case where the cord type heaters  28  generate heat, the heat generated by the cord type heaters  28  is transferred to the cover members  25 , and the transferred heat is transferred throughout the cover members  25  composed of a metal material. Therefore, the temperatures of the whole cover members  25  rise. 
     Also, the flow direction of the preliminary air Ap blown from the air blowing fans  45  by the air blowing fans  45  is changed by the air-flow-direction changing wall parts  60 , such that the preliminary air flows toward the gap between the medium  100  and the cover members  25 . Specifically, the preliminary air Ap blown from the air blowing fan  45  flows into the widening ducts  50 . Since the widening ducts  50  have the widening-duct openings  54  formed at their end portions on the wider side, the preliminary air Ap entering the widening ducts  50  flows toward the widening-duct openings  54 , that is, toward the end portions on the wider side. 
     Since the plurality of current plates  55  is disposed inside the widening ducts  50 , the preliminary air Ap flowing in the widening ducts  50  toward the openings  54  positioned on the wider side passes through the current plates  55 , thereby being rectified. In other words, the preliminary air Ap flowing in the widening ducts  50  is rectified by the current plates  55 , whereby turbulence of the flow is reduced, and in this state, the preliminary air smoothly flows in the widening ducts  50  toward the end portions. 
     If the preliminary air Ap flows in the widening ducts  50  as described above, thereby reaching a side of the widening-duct opening  54  positioned on the wider side of the widening ducts  50 , the preliminary air is sent out from the widening ducts  50  through the widening-duct openings  54  positioned near the air-flow-direction changing wall part  60 . 
     The preliminary air Ap flowing from the widening ducts  50  to the outside of the widening ducts  50  through the widening-duct openings  54  is guided to the air-flow-direction changing wall parts  60  of the first heating element cover  31  while flowing toward the air outlets  61 . The air flowing toward the air outlets  61  passes through the air outlets  61 , thereby flowing from the inside of the first heating element  21  to the outside of the first heating element  21 . Since the air outlets  61  are open substantially downward, the air flowing out from the air outlets  61  flows downward. Therefore, the preliminary air Ap flowing out from the air outlet  61  flows, as the drying air flow Fd for drying ink ejected on the medium  100 , toward the gap between the medium  100  and the cover members  25 . 
     Since the air blowing fans  45  blow air only inside the widening ducts  50 , whereby the preliminary air Ap in the widening ducts  50  is sent out from the widening-duct openings  54 , the flow direction of all of the air which is sent from the air blowing fans  45  toward the gap between the medium  100  and the cover members  25  is changed by the air-flow-direction changing wall parts  60 . In other words, the flow direction of the preliminary air Ap sent from the air blowing fans  45  is changed by the air-flow-direction changing wall part  60 , whereby the preliminary air flows as the drying air flow Fd into the air flow path  90  between the medium  100  and the cover members  25 . 
     As described above, since the temperatures of the cover members  25  which constitute the air flow path  90  together with the medium  100  are increased by heat generation of the cord type heaters  28 , the temperature of the drying air flow Fd which flows in the air flow path  90  also rises due to radiant heat from the cover members  25 . In the air flow path  90 , the air blown from the air blowing fans  45  is sequentially sent downward from the air outlets  61  while air heated by radiant heat from the cover members  25  tends to move upward. Therefore, the drying air flow Fd in the air flow path  90  is agitated while being heated. 
     During printing of the printing apparatus  1 , after ink ejected from the head  4  lands on the medium  100 , the medium is conveyed from the top of the platen  7  toward the winding roller  12  by the driver  10 , thereby moving into the air flow path  90 . Ink on the medium  100  moving into the air flow path  90  after landing of ink ejected from the head  4  may be wet still. However, since the drying air flow Fd in the air flow path  90  has been heated and agitated, the whole of a portion of the medium  100  which is positioned in the air flow path  90  is heated by the drying air flow Fd having been heated and agitated while steam arising from the ink is removed. Therefore, if ink is ejected from the head  4  and lands on a portion of the medium  100 , and the portion of the medium  100  is positioned in the air flow path  90 , the ink appropriately dries. 
     Also, most of air flowing from the air outlet  61  of the dryer  20  into the air flow path  90  flows downward. However, in some cases such as a case where the volume of air is large, the flow of the air may become turbulent, thereby flowing upward. In this case, it can be considered that a portion of the air flows toward the head  4  of the printing apparatus main body  2 . Even in this case, since the printing apparatus main body  2  has the partition plate  18  which separates the air outlets  61  and the head  4 , the air flowing toward the head  4  is blocked by the partition plate  18 . 
     After ink on the medium  100  is dried by the drying air flow Fd flowing from the dryer  20  into the air flow path  90 , the medium is sequentially conveyed by the driver  10 , toward the winding roller  12  and is wound around the winding roller  12 . When the printing apparatus  1  performs printing on the medium  100 , as described above, printing is performed by the printing apparatus main body  2  while the medium  100  is conveyed, and ink on the medium  100  is dried by the dryer  20 . In this way, printing is continuously performed on the roll-like medium  100 . 
     Also, in the above described embodiment, air flowing into the air flow path  90  is heated by the heaters provided on the cover members  25 . However, the heater is not limited to the heaters provided on the cover members  25 , and a method of directly heating an air flow, such as a method of heating an air flow by a heater before or after the direction of the air flow is changed by the air-flow-direction changing wall parts  60  can be applied. 
     In a case where printing of the printing apparatus  1  has finished, the dryer  20  is folded if necessary.  FIG. 9  is a perspective view illustrating the dryer in a case of folding the dryer shown in  FIG. 8 . In the case of folding the dryer  20 , the user holds the handles  35  provided on the first heating element  21  and draws them up, thereby relatively rotating the first heating element  21  with respect to the second heating element  22  such that the engagement members  73  of the first heating element  21  engaged with the engagement portions  72  formed in the folding/unfolding guides  71  of the side plates  70  move along the folding/unfolding guides  71 . 
     Specifically, the engagement members  73  are moved downward along the folding/unfolding guides  71 , whereby the first cover part  26  and the second cover part  27  rotate so as to be almost horizontal. In this case, the second cover part  27  relatively rotates on the rotation connection parts  24  with respect to the fixing members  75 , and the first cover part  26  relatively rotates with respect to the second cover part  27  by the hinge  23 . In this way, the first cover part  26  and the second cover part  27  rotate toward each other so as to come close. 
       FIG. 10  is a perspective view illustrating the dryer shown in  FIG. 9  in a state where the dryer is folded. If the first heating element  21  and the second heating element  22  are relatively rotated, whereby the engagement members  73  provided on the first heating element  21  reach the lower ends of the folding/unfolding guides  71  formed in the side plates  70 , the engagement members  73  cannot be moved downward from the lower ends of the folding/unfolding guides. This state of the dryer  20  is the state where the first heating element  21  and the second heating element  22  are folded. The first heating element  21  and the second heating element  22  which can be folded as described above are configured by connecting them by the hinge  23  such that the cover members  25  do not protrude into the conveyance path  8  during expansion or contraction of the cover members  25 . Therefore, the first heating element  21  and the second heating element  22  relatively rotate such that, when the first heating element  21  and the second heating element  22  are folded, thereby contracting in the conveyance direction of the medium  100 , their end portion sides connected to the hinge  23  move away from the platen  7 . Therefore, in a state where the first heating element  21  and the second heating element  22  are folded, since the first cover part  26  faces substantially downward, and the second cover part  27  faces substantially upward, the first cover part  26  and the second cover part  27  substantially face each other. In other words, in the dryer  20 , when the first heating element  21  and the second heating element  22  are folded, the first cover part  26  and the second cover part  27  are positioned on the inner side. 
       FIG. 11  is a perspective view illustrating the printing apparatus in a state where the dryer is folded. In a case where the dryer  20  is folded, in the printing apparatus  1 , a portion of the platen  7  of the printing apparatus main body  2  positioned on a side of the dryer  20  is exposed. Therefore, in the case where the dryer  20  is folded, it is easy to perform maintenance such as setting of the medium  100  in the printing apparatus main body  2 . 
     In the printing apparatus  1  according to the above described embodiment, since the flow direction of the preliminary air Ap blown from the air blowing fans  45  is changed by the air-flow-direction changing wall parts  60  provided at the dryer  20 , and then the preliminary air flows, as the drying air flow Fd, toward the gap between the medium  100  and the cover members  25 , it is possible to suppress air blown from the air blowing fans  45  from straightly flowing. Therefore, it is possible to suppress an uneven air flow from being created on the medium  100 , and it is possible to suppress cockling from occurring. As a result, it is possible to dry ink on the medium  100  while suppressing cockling from occurring. Also, since heating of at least one of the drying air flow Fd and the preliminary air Ap by the cord type heaters  28  and an air flow with little unevenness are used to raise the temperature of the air flow path  90 , it is possible to easily perform temperature management during drying of ink. 
     Also, since the air blowing fans  45  blow the preliminary air Ap, whereby the preliminary air Ap collides with the air-flow-direction changing wall parts  60 , whereby the flow direction is changed such that the preliminary air is used as the drying air flow Fd, it is possible to easily create the drying air flow Fd to flow toward the gap between the medium  100  and the cover members  25 . As a result, it is possible to easily dry ink on the medium  100 . 
     Also, since the plurality of current plates  55  is provided inside the widening ducts  50 , it is possible to evenly send wind out from the widening-duct openings  54 , and it is possible to evenly send wind into the air flow path  90 . As a result, the volume of air flow is uniformized, and it is possible to suppress unevenness in heating which is performed by the cord type heaters  28 , and it is possible to suppress ink from being unevenly dried. 
     Also, since the air-flow-direction changing wall parts  60  direct the preliminary air Ap, blown from the air blowing fans  45 , downward, thereby sending the preliminary air as the drying air flow Fd toward the gap between the medium  100  and the cover members  25 , in a case where air is heated by the cord type heaters  28 , thereby flowing upward, it is possible to direct the flow of air downward. As a result, it is possible to make warm air stay between the cover members  25  and the medium  100 , and it is possible to improve drying efficiency. Also, since air blown from the air blowing fans  45  is directed downward, it is possible to make it difficult for heat generated by the cord type heaters  28  to be transferred to the head  4 . Therefore, it is possible to reduce adverse effects such as poor ink ejection attributable to drying of nozzles. 
     Also, since the cord type heaters  28  heat the cover members  25 , thereby heating the drying air flow Fd in the air flow path  90 , it is possible to perform temperature management by detecting the temperatures of the cover members  25 . Therefore, it is possible to improve the reliability of temperature management. Also, in a case of heating the drying air flow Fd in the air flow path  90 , the cover members  25  are also heated. Therefore, it is possible to improve heating efficiency during heating of the drying air flow Fd. Also, since the inexpensive cord type heaters  28  are used as heater, it is possible to suppress the manufacturing cost. Further, since the cord type heaters  28  are bonded to the cover members  25 , it is possible to thin the heating element covers  30  for covering the cord type heaters  28 , and it is possible to make the whole dryer  20  compact. 
     Also, since the cord type heaters  28  are provided throughout the width direction of the medium  100  in the main scan direction, it is possible to suppress a reduction in temperature at joints of heaters. In other words, for example, unlike in a case of using glass tube heaters or sheath heaters as heater, it is possible to suppress a reduction in temperature at joints. As a result, it is possible to more surely and evenly heat air in the air flow path  90 . 
     Also, since the direction of the whole of the drying air flow Fd which is sent from the air blowing fans  45  toward the gap between the medium  100  and the cover members  25  is changed by the air-flow-direction changing wall parts  60 , whereby unevenness of the air flow is reduced, it is possible to suppress a drying air flow Fd having been unevenly heated from coming into contact with the medium  100 . As a result, it is possible to more surely suppress cockling attributable to uneven drying or a variation in temperature. 
     Also, since the partition plate  18  is provided between the air outlet  61  and the head  4 , it is possible to suppress a flow of heated air from reaching the head  4 , thereby suppressing the heated air from drying ink on the ejection ports of the head  4 . As a result, printing failures are prevented from being caused by drying of ink on the ejection ports of the head  4 , and it is possible to dry ink on the medium  100 . 
     Also, since the first heating element  21  and the second heating element  22  of the dryer  20  are connected so as to be able to relatively rotate, it is possible to fold the first heating element  21  and the second heating element  22  on the occasion of setting the medium  100 , and to unfold the first heating element  21  and the second heating element  22  on the occasion of starting printing. As a result, it is possible to suppress ease of setting of the medium  100  from being damaged, and provide the cover members  25  at positions facing the medium  100 . Also, even in a case where the medium  100  is jammed or a trouble occurs in the dryer  20 , if necessary, it is possible to unfold and fold the first heating element  21  and the second heating element  22 , whereby it is possible to handle those troubles. As a result, it is possible to improve maintainability. 
     Also, the cord type heaters  28  and the air blowing fans  45  are stored inside the first heating element  21  which is configured using the first cover part  26 , it is possible to improve heating efficiency due to heat insulating effect while saving space. Therefore, it is possible to evenly heat the space between the cover members  25  and the medium  100 , and it is possible to suppress temperature unevenness. As a result, it is possible to dry ink on the medium  100  while suppressing cockling from occurring. 
     Also, since the air blowing fans  45  are provided at positions on the opposite sides of the cord type heaters  28  to the platen  7  so as to overlap the cord type heaters  28 , it is possible to suppress the air blowing fans  45  from protruding outward from the area where the cord type heaters  28  are provided, thereby suppressing the air blowing fans from occupying a large space. As a result, it is possible to save space. 
     Also, since the drying air flow Fd or the preliminary air Ap is sent from the air outlets  61  formed at the top of the first heating element  21 , it is possible to suppress the heated drying air flow Fd positioned between the platen  7  and the cover members  25  from exiting from the upper side in the direction of gravity. In other words, since the heated drying air flow Fd tends to move upward, but is sent downward from the air outlets  61  formed at the top of the first heating element  21 , it is possible to suppress the drying air flow Fd from exiting upward from the gap between the platen  7  and the cover members  25 . As a result, it becomes easy to hold the heated drying air flow Fd between the platen  7  and the cover members  25 , and it is possible to further improve the heating efficiency. 
     Modifications 
     Also, in the printing apparatus  1  according to the above described embodiment, if air is blown from the air blowing fans  45  toward the gap between the cover members  25  and the medium  100 , and enters the gap, the air is heated by the cord type heaters  28  with the cover members  25  interposed between. However, air may be heated before being sent into the gap between the cover members  25  and the medium  100 . For example, cord type heaters  28  may be disposed inside the widening ducts  50 . In this case, air heated in the widening ducts  50  may be sent out from the air outlets  61  and flow into the gap between the cover members  25  and the medium  100 . In a case where air is directed substantially downward by the air-flow-direction changing wall parts  60  and then flows into the gap between the cover members  25  and the medium  100 , the heating timing may be before or after the air enters the gap between the cover members and the medium. 
     Also, in the printing apparatus  1  according to the above described embodiment, the air-flow-direction changing wall parts  60  are used as the flow path changer for changing the flow direction of the preliminary air Ap. However, as the flow path changer, devices other than the air-flow-direction changing wall parts  60  may be used.  FIG. 12  is a view for explaining a case of using air blowing fans as flow path changer, as a modification of the printing apparatus according to the embodiment. For example, air blowing fans  110  which are air blower may be provided on the upper side of the first cover part  26  as shown in  FIG. 12 , and be used as flow path changer. In this case, the air blowing fans  110  are provided not only as drying-air-flow supply for sending the drying air flow Fd into the gap between the medium  100  and the cover members  25  but also as flow path changer. Specifically, the air blowing fans  110  are disposed so as to be able to send air from the above of the air flow path  90  between the medium  100  and the cover members  25  into the air flow path  90 . In this case, the air blowing fans  110  are disposed such that, if the preliminary air Ap positioned on the opposite side of the cover members  25  to the medium  100  is heated, the preliminary air ascends toward the air blowing faces of the air blowing fans  110 . 
     In this case, if the preliminary air Ap positioned on the opposite side of the cover members  25  to the medium  100  is heated by the cord type heaters  28  provided on the cover members  25 , the heated preliminary air Ap is sent into the gap between the medium  100  and the cover members  25  by the air blowing fans  110 . In other words, the air blowing fans  110  change the flow direction of the heated preliminary air Ap, thereby sending the preliminary air Ap as the drying air flow Fd into the gap between the medium  100  and the cover members  25 . If the drying air flow Fd enters the gap between the medium  100  and the cover members  25 , the drying air flow in the gap is heated by the cord type heaters  28 , whereby the temperature rises. Therefore, it is possible to easily send the drying air flow Fd toward the gap between the medium  100  and the cover members  25 , and it is possible to easily dry ink on the medium  100  by the drying air flow Fd. 
     Also, the flow path changer may suck air, thereby changing the flow direction of the preliminary air Ap.  FIG. 13  is a view for explaining a case of using air intake fans as flow path changer, as another modification of the printing apparatus according to the embodiment. For example, air intake fans  120  which are air breathers may be provided below the second cover part  27  as shown in  FIG. 13 , and be used as flow path changer. In this case, the air intake fans  120  are provided not only as drying-air-flow supply for sending the drying air flow Fd into the gap between the medium  100  and the cover members  25  but also as flow path changer. Specifically, the air intake fans  120  are provided so as to be able to suck the drying air flow Fd in the air flow path  90  from below the air flow path  90  between the medium  100  and the cover members  25 . In this case, it is preferable to form the upper end portion of the first heating element cover  31  so as to cover even the upper side of the first cover part  26  such that the preliminary air Ap positioned on the opposite side of the first cover part  26  to the medium  100  flows into the gap between the medium  100  and the cover members  25 , without flowing upward. 
     If the air intake fans  120  are provided as described above, the air intake fans  120  can suck the drying air flow Fd in the air flow path  90  between the medium  100  and the cover members  25 , from below of the air flow path  90 , and send the drying air flow downward. In a case where the drying air flow Fd in the air flow path  90  flows downward, since a negative pressure is produced inside the air flow path  90 , the preliminary air Ap positioned on the opposite side of the first cover part  26  to the medium  100  flows from the upper end side of the first cover part  26  into the air flow path  90  between the medium  100  and the cover members  25 . In other words, the air intake fans  120  suck the drying air flow Fd in the gap between the medium  100  and the cover members  25 , thereby changing the flow direction of the preliminary air Ap positioned on the opposite side of the cover members  25  to the medium  100 , such that the preliminary air flows as the drying air flow Fd into the gap between the medium  100  and the cover members  25 . Since the preliminary air Ap is heated by the cord type heaters  28  disposed on the cover members  25 , whereby its temperature rises, the temperature of the drying air flow Fd to flow into the gap between the medium  100  and the cover members  25  also rises. Also, the drying air flow Fd in the gap between the medium  100  and the cover members  25  is heated by the cord type heaters  28 , whereby its temperature rises. Therefore, it is possible to easily send the drying air flow Fd toward the gap between the medium  100  and the cover members  25 , and it is possible to easily dry ink on the medium  100  by the drying air flow Fd. Also, since the preliminary air Ap entering the dryer  20  from the outside is also sucked downward by the air intake fans  120 , the flow direction of a high proportion of the preliminary air can be changed such that the preliminary air is introduced into the gap between the medium  100  and the cover members  25 . 
     Also, heater may be provided on the platen  7 , and the set temperatures of the heater may differ depending on positions on the conveyance path  8 .  FIG. 14  is a view for explaining cord type heaters which are provided on an after-platen, as another modification of the printing apparatus according to the embodiment.  FIG. 15  is a detailed view of a portion including the after-platen shown in  FIG. 14 .  FIG. 16  is a view as seen in a direction shown by arrows C-C of  FIG. 15 . In the case of providing heater on the platen  7 , for example, as shown in  FIGS. 14 to 16 , cord type heaters  135  may be buried as heater in an after-platen  130  which is a portion of the platen  7  and is positioned on the downstream side from the scanning area of the head  4  in the movement direction of the medium  100 . In other words, the after-platen  130  is composed of a member for supporting a portion of the medium  100  positioned on the downstream side from the head  4  in the movement direction of the medium  100  relative to the head  4 , and on the after-platen  130 , the cord type heaters  135  are provided as recording-medium heater for heating the medium  100 . Similarly to the cord type heaters  28  (see  FIG. 7 ) which are bonded to the cover members  25 , the cord type heaters  135  are disposed along the main scan direction on the after-platen  130 , and are turned in the vicinities of the end portions of the after-platen  130  in the main scan direction. Therefore, portions of the cord type heaters  135  along the main scan direction are disposed in parallel in the movement direction of the medium  100 . 
     As described above, the cord type heaters  135  which are provided on the after-platen  130  are configured such that some of them positioned on the downstream side in the movement direction of the medium  100  heat the medium  100  at a higher temperature than the others positioned on the upstream side. Specifically, on the after-platen  130 , as the cord type heaters  135 , upstream cord type heaters  136  to be disposed on the relatively upstream side, and downstream cord type heaters  137  to be disposed on the downstream side from the upstream cord type heaters  136  are provided. On the after-platen  130 , a heating area  156  is set as an area where the medium  100  is heated by the cord type heaters  135 . In other words, since the upstream cord type heaters  136  and the downstream cord type heaters  137  are provided as the cord type heaters  135 , as the heating area  156 , an upstream area A 1  which is an area where heating is performed by the upstream cord type heaters  136 , and a downstream area A 2  which is an area where heating is performed by the downstream cord type heaters  137  are set. 
     Specifically, the after-platen  130  where the heating areas  156  are set is formed in a curved shape such that a portion close to the upstream end in the movement direction of the medium  100  gradually curves from a horizontal state to a vertical state as it goes toward the downstream side in the movement direction of the medium  100 . The heating area  156  is an area of the after-platen  130  where the cord type heaters  135  are disposed, and is provided from the vicinity of the portion of the after-platen  130  where the curve is formed in the movement direction of the medium  100 , to the downstream side in the movement direction of the medium  100 . Of the upstream area A 1  and the downstream area A 2  constituting the heating area  156 , the upstream area A 1  is set such that the length in the movement direction of the medium  100  becomes about one-third of the length of the heating area  156 , and the downstream area A 2  is set such that the length in the movement direction of the medium  100  becomes about two-third of the length of the heating area  156 . In other words, the upstream cord type heaters  136  are disposed in the range of one-third of the heating area  156  positioned on the upstream side in the movement direction of the medium  100 , and the downstream cord type heaters  137  are disposed in the range of two-third of the heating area  156  positioned on the downstream side in the movement direction of the medium  100 . 
     Also, the set temperatures of the cord type heaters  135  for heating differ between the upstream cord type heaters  136  and the downstream cord type heaters  137 , and the set temperature T 2  of the downstream cord type heaters  137  is set to be higher than the set temperature T 1  of the upstream cord type heaters  136 . In other words, in the heating area  156  for heating the medium  100 , the set temperature T 2  of the downstream area A 2  is set to be higher than the set temperature T 1  of the upstream area A 1 . For example, the set temperature T 2  of the downstream area A 2  may be set to be higher than the set temperature T 1  of the upstream area A 1  by about 10° C., and the set temperature T 1  of the upstream area A 1  and the set temperature T 2  of the downstream area A 2  may be appropriately set to have such a temperature difference. 
     In the case where the cord type heaters  135  are provided on the after-platen  130  as described above, during printing of the printing apparatus  1 , if a portion of the medium  100  where ink ejected from the head  4  has landed reaches the position of the heating area  156 , it is possible to heat the medium  100  by the cord type heaters  135 . In this way, the cord type heaters  135  can dry ink on the medium  100 . In this case, in the heating area  156 , the set temperature T 1  of the upstream area A 1  is set to be higher than the set temperature T 2  of the downstream area A 2 , and the upstream area A 1  is provided as an area for performing low-temperature drying, and the downstream area A 2  is provided as an area for performing high-temperature drying. 
     Therefore, when the medium  100  passes the heating area  156 , ink on the medium is moderately dried at a relatively low temperature by the upstream cord type heaters  136  in the upstream area A 1 , and then is appropriately dried at a relatively high temperature by the downstream cord type heaters  137  in the downstream area A 2 . In this way, when the medium  100  passes the heating area  156 , the upstream area A 1  serves as a buffer zone for suppressing sudden drying. Therefore, it is possible to suppress cockling from occurring. 
     Also, on the platen  7 , members for supporting the medium  100  moving during printing may be provided.  FIG. 17  is a view as seen in a direction shown by arrows A-A of  FIG. 14 .  FIG. 18  is a view as seen in a direction shown by arrows B-B of FIG.  17 . As the members for supporting the medium  100 , for example, as shown in  FIGS. 14 to 18 , medium pressing members  140  which are recording medium members for regulating movement of the medium  100  in the width direction and thickness direction of the medium  100  may be attached to the platen  7 . In a head scan area  155  which is an area where the head  4  ejects ink onto the medium  100 , in the movement direction of the medium  100  relative to the head  4 , the medium pressing members  140  are disposed at two positions corresponding to the positions of both ends of the medium  100  in the main scan direction. Also, the head scan area  155  is an area where the head  4  reciprocates in the main scan direction during printing of the printing apparatus  1 , that is, an ejectable area where the head  4  can eject ink. 
     The medium pressing members  140  which are provided at two positions corresponding to the positions of both ends of the medium  100  in the main scan direction as described above are disposed throughout the head scan area  155  and the position of the upstream end of the heating area  156  in the movement direction of the medium  100  relative to the head  4 . In other words, the medium pressing members  140  are disposed from a position in the vicinity of the upstream end of the head scan area  155  in the movement direction of the medium  100  to the position of the upstream end of the upstream area A 1  of the heating area  156 . Therefore, the length Lh of the medium pressing members  140  in the sub scan direction is greater than the length Ls of the head scan area  155  in the sub scan direction. 
     The medium pressing members  140  which are provided as described above include vertical direction regulation parts  141  for regulating movement of the medium  100  upward, horizontal direction regulation parts  142  for regulating movement of the medium in a horizontal direction, and base parts  145  which are used to attach the medium pressing members  140  to the platen  7 . Of them, the horizontal direction regulation parts  142  are provided as wall parts which are connected to end portions of the base parts  145  in the sub scan direction and protrude upward from the end portions of the base parts  145 . Also, the vertical direction regulation parts  141  are provided as wall parts which protrude from the upper end portions of the horizontal direction regulation parts  142  toward the opposite sides of the horizontal direction regulation parts  142  to the base parts  145  in the main scan direction. In other words, each of pairs of the vertical direction regulation parts  141  and the horizontal direction regulation parts  142  is formed substantially in an inverted L shape as the medium pressing members  140  are seen in the sub scan direction. 
     Two pairs of the vertical direction regulation parts  141  and the horizontal direction regulation parts  142  are provided at two positions of one medium pressing member  140 , and those pairs of the vertical direction regulation parts  141  and the horizontal direction regulation parts  142  are provided on both sides of the corresponding medium pressing member  140  in the main scan direction. In other words, each medium pressing member  140  is formed so as to be axis-symmetrical with respect to the central portion in the main scan direction as the corresponding medium pressing member  140  is seen in the sub scan direction. 
     The base parts  145  have engagement portions  146  which are fit into grooves  150  which are formed in the platen  7 , whereby the medium pressing members  140  which are formed as described above are attached to the platen  7 . The plurality of grooves  150  is formed in the surface of the platen  7  for mounting the medium  100 , so as to extend in the main scan direction. The engagement portions  146  of the medium pressing members  140  are formed at positions on the lower surfaces of the base parts  145  corresponding to the grooves  150  of the platen  7 , so as to protrude downward. The engagement portions  146  are fit into the grooves  150  of the platen  7 , whereby the medium pressing members  140  are attached to the platen  7 . 
     In this case, two medium pressing members  140  are attached to the platen  7  such that the interval between horizontal direction regulation parts  142  included in the two medium pressing members  140  and facing each other is slightly larger than the width of the medium  100  in the main scan direction. In this way, the medium pressing members  140  are disposed throughout at least the head scan area  155  in the movement direction of the medium  100 , and are attached to the platen  7  such that the interval between the horizontal direction regulation parts  142  of the two medium pressing members  140  is slightly larger than the width of the medium  100  in the main scan direction. 
     The medium pressing members  140  are attached to the platen  7  with a gap between the vertical direction regulation parts  141  of the medium pressing members  140  and the platen  7 . During printing of the printing apparatus  1 , the medium  100  which moves on the platen  7  passes through the gap between the vertical direction regulation parts  141  and the platen  7 . Therefore, movement of the medium  100  upward is regulated by the vertical direction regulation parts  141 . Also, since the medium  100  which moves on the platen  7  passes between the horizontal direction regulation parts  142  of the medium pressing members  140  disposed near both ends of the medium  100  in the main scan direction, movement of the medium  100  in the main scan direction is regulated by the horizontal direction regulation parts  142 . As described above, during printing of the printing apparatus  1 , it is possible to regulate movement of the medium  100  in the vertical direction and the main scan direction, that is, movement of the medium  100  in the thickness direction and width direction of the medium  100 . Therefore, it is possible to suppress cockling from occurring. 
     Also, since the medium pressing members  140  are disposed throughout the head scan area  155  and the position of the upstream end of the upstream area A 1  included in the heating area  156  in the movement direction of the medium  100  relative to the head  4 , in a state where ink ejected on the medium  100  is wet, it is possible to hold the medium  100  by the medium pressing members  140 . Since the medium  100  moves to the heating area  156  while being held by the medium pressing members  140 , after a predetermined time from ink ejection, drying is performed in the heating area  156 . Therefore, it becomes difficult for the medium  100  to be suddenly deformed, and it is possible to effectively suppress cockling from occurring. 
     Also, since each medium pressing member  140  is formed such that the shape in the main scan direction is symmetrical with respect to the central portion in the main scan direction, it is possible to use each medium pressing member  140  on any end portion side of both end portions of the medium  100  in the main scan direction. However, the medium pressing members  140  do not necessarily need to have a symmetrical shape in the main scan direction. As long as the medium pressing members  140  have the vertical direction regulation parts  141  and the horizontal direction regulation parts  142 , it is possible to regulate movement of the medium  100  in the vertical direction and the main scan direction. 
     Also, in the printing apparatus  1  according to the above described embodiment, in the printing apparatus main body  2 , the head  4  is provided so as to move along the Y bar  5 , and during printing, the head  4  performs printing while reciprocating in the main scan direction. However, the head  4  may be provided so as to extend in the main scan direction. In other words, the head  4  may be provided so as to be able to eject ink over the entire print range in the main scan direction, and be configured such that, during printing, the head  4  can perform printing on the entire print range in the main scan direction at once without moving in the main scan direction. As long as the printing apparatus main body  2  is configured so as to be able to eject ink onto the medium  100  and be able to convey the medium  100  to the position of the dryer  20  after ink lands on the medium, the configuration of the head  4  does not matter. 
     Also, the above described printing apparatuses  1  according to the embodiment and modifications of the present disclosure are not limited to the embodiment and the modifications described above, and the components of the embodiment and the modifications can be appropriately combined.