Patent Publication Number: US-11385576-B2

Title: Printing apparatus and control method thereof

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a printing apparatus and a control method thereof. 
     Description of the Related Art 
     Conventionally, there is known a printer including a heating device represented by a fixing device in a conveyance path of a print medium. In such a printer, the heating device may be inserted into and removed from the printer main body at the time of jam clearance or replacement of the fixing device. Since the heating device may be in a high temperature state caused by its operation, there is disclosed a technique of disabling insertion/removal of the heating device to/from the printer main body if the fixing device is at a temperature equal to or higher than a predetermined temperature, and enabling such insertion/removal if the fixing device is below the predetermined temperature (Japanese Patent Laid-Open No. 2013-140322). 
     SUMMARY OF THE INVENTION 
     According to one embodiment of the present invention, a printing apparatus comprises, a printing unit configured to print an image on a print medium, a heating unit configured to heat the print medium with the image printed thereon, a detection unit configured to detect a temperature of the heating unit, a housing configured to accommodate the printing unit and the heating unit, an openable/closable cover member provided on the housing and configured to cover the heating unit, a restricting unit capable of restricting an opening operation of the cover member, and a control unit configured to control the restricting unit so as to execute the restriction if the temperature of the heating unit exceeds a first threshold value, and release the restriction if the temperature of the heating unit is not more than a second threshold value lower than the first threshold value. 
     According to another embodiment of the present invention, a control method of a printing apparatus including a printing unit configured to print an image on a print medium, a heating unit configured to heat the print medium with the image printed thereon, a housing configured to accommodate the printing unit and the heating unit, an openable/closable cover member provided on the housing and configured to cover the heating unit, and a restricting unit capable of restricting an opening operation of the cover member, the method comprises, detecting a temperature of the heating unit, and controlling the restricting unit so as to execute the restriction if the temperature of the heating unit exceeds a first threshold value, and release the restriction if the temperature of the heating unit is not more than a second threshold value lower than the first threshold value. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a printing system; 
         FIG. 2  is a schematic view of a printing apparatus; 
         FIG. 3  is an explanatory view of a drying promotion unit; 
         FIG. 4  is an explanatory view of an exhaust unit; 
         FIG. 5  is a block diagram of a control unit of a main body apparatus; 
         FIG. 6  is an explanatory view of the operation of the printing apparatus shown in  FIG. 2 ; 
         FIG. 7  is an explanatory view of the operation of the printing apparatus shown in  FIG. 2 ; 
         FIG. 8  is an explanatory view of the operation of the printing apparatus shown in  FIG. 2 ; 
         FIG. 9  is an explanatory view of the operation of the printing apparatus shown in  FIG. 2 ; 
         FIG. 10A  is a schematic view of a cover member and a restricting mechanism in a closed state; 
         FIG. 10B  is a schematic view of the cover member and the restricting mechanism in the closed state; 
         FIG. 10C  is a schematic view of the cover member and the restricting mechanism in an open state; 
         FIG. 10D  is a schematic view of the cover member and the restricting mechanism in the open state; 
         FIG. 11A  is a sectional view taken along a line I-I in  FIG. 10A ; 
         FIG. 11B  is a sectional view showing a state in which a displacement member is set in a release position; 
         FIG. 12A  is a flowchart illustrating an example of processing executed by a restricting mechanism controller; 
         FIG. 12B  is a flowchart illustrating the example of the processing executed by the restricting mechanism controller; 
         FIG. 13A  is a flowchart illustrating another example of the processing executed by the restricting mechanism controller; 
         FIG. 13B  is a flowchart illustrating an example of processing executed by a display controller; 
         FIG. 13C  is an example of display by the display unit. 
         FIG. 14  is a flowchart illustrating another example of the processing executed by the display controller; 
         FIG. 15A  is a front view showing an arrangement example of a drying promotion unit; 
         FIG. 15B  is a sectional view taken along a line II-II in  FIG. 15A ; 
         FIG. 16A  is a front view showing another arrangement example of the drying promotion unit; 
         FIG. 16B  is a sectional view taken along a line III-III in  FIG. 16A ; 
         FIG. 17A  is a schematic front view showing a case in which a grip portion of the drying promotion unit shown in  FIG. 16A  is in an extended state; 
         FIG. 17B  is a sectional view taken along a line IV-IV in  FIG. 17A ; 
         FIG. 18  is a front view showing another arrangement example of the drying promotion unit; 
         FIG. 19A  is a front view showing still another arrangement example of the drying promotion unit; 
         FIG. 19B  is a view taken in the direction of an arrow A in  FIG. 19A  and showing an example of openings formed in the drying promotion unit; 
         FIG. 19C  is a view taken in the direction of the arrow A in  FIG. 19A  and showing another example of the openings formed in the drying promotion unit; and 
         FIG. 19D  is a view taken in the direction of the arrow A in  FIG. 19A  and showing still another example of the openings formed in the drying promotion unit. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The above-described conventional technique only disables the insertion/removal so that the heating device may be exposed to the outside. There is room for improvement in this point. 
     An embodiment of the present invention provides a technique of suppressing exposure of the device in a high temperature state to the outside. 
     Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note, the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but limitation is not made an invention that requires all such features, and multiple such features may be combined as appropriate. Furthermore, in the attached drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted. 
     &lt;Arrangement of Printing System&gt; 
       FIG. 1  is a front view of a printing system  1  according to an embodiment of the present invention. In the drawings including  FIG. 1 , arrows X and Y indicate a horizontal direction and a depth direction, respectively, which are perpendicular to each other. An arrow Z indicates a vertical direction. 
     The printing system  1  includes a main body apparatus  2  and a post processing apparatus  3 . The main body apparatus  2  according to this embodiment is an apparatus forming a multi-function peripheral, and has a copy function, a scanner function, and a printer function. The main body apparatus  2  includes a reading apparatus  4 , a printing apparatus  5 , and a feeding apparatus  6 , and an operation unit  7  is provided in the front portion of the main body apparatus  2 . The operation unit  7  serves as an input/output interface with a user, and includes, for example, an acceptance unit such as hard keys that accepts input from the user, and a display unit  7   a  such as a liquid crystal display that displays information. The operation unit  7  may be a touch panel that serves as the display unit  7   a  to accept input from the user and display information. The operation unit  7  also includes an output unit such as a voice generator. 
     The reading apparatus  4  includes an ADF (Automatic Document Feeder), and conveys stacked documents and reads document images. The feeding apparatus  6  is an apparatus that feeds a print medium to the printing apparatus  5 . In this embodiment, the print medium is a sheet such as paper or a film, and is particularly a cut sheet. The print medium may be referred to as a sheet hereinafter. The feeding apparatus  6  includes a plurality of cassettes  6   a  on which sheets are stacked, and a feeding mechanism (not shown) that feeds a sheet from the cassette  6   a  to the printing apparatus  5  on a conveyance path RT. 
     The printing apparatus  5  prints an image on the sheet. The printing apparatus  5  includes a printing unit  30  that prints an image by discharging ink to a sheet, and a first drying promotion unit  40  and a second drying promotion unit  50  that promote drying of the sheet. Details of the printing apparatus  5  will be described later. 
     The post processing apparatus  3  serves as a finisher (sheet processing apparatus) that is separably attached to a side portion of the main body apparatus  2  as an optional apparatus and performs post processing of the sheet. The post processing includes, for example, a stacking processing of stacking, on a tray  3   a , a sheet discharged from the printing apparatus  5 , a sort processing of taking in a plurality of sheets discharged from the printing apparatus  5  and aligning and bundling them, stapling processing of binding bundled sheets by staplers, binding processing, and punching processing. 
     &lt;Arrangement of Printing Apparatus&gt; 
       FIG. 2  is an explanatory view showing the internal arrangement of the printing apparatus  5 . The printing apparatus  5  includes, as a frame for supporting the internal mechanism, a bottom wall portion  5   a , an upper wall portion  5   b , a right wall portion  5   c , a left wall portion  5   d , and a back wall portion  5   e . These wall portions define the internal space of the printing apparatus  5 . The internal space of the printing apparatus  5  is divided into a lower space SP 1  and an upper space SP 2  by a partition wall  5   h . The spaces SP 1  and SP 2  are not hermetically divided, and communicate with each other. 
     The bottom wall portion  5   a  includes an opening  5   f  through which a sheet fed from the feeding apparatus  6  passes. The right wall portion  5   c  includes an opening  5   g  through which a sheet passes to be discharged to the post processing apparatus  3 . For example, the left wall portion  5   d  and the right wall portion  5   c  may be supported to be opened/closed in a door type for maintenance. Alternatively, for example, an opening may be partially formed in each of the left wall portion  5   d  and the right wall portion  5   c  for maintenance, and a cover member may be provided so as to cover each opening. 
     In this embodiment, for jam clearance, replacement of the second drying promotion unit  50 , and the like, the left wall portion  5   d  is pivotably supported. That is, in this embodiment, the bottom wall portion  5   a , the upper wall portion  5   b , the right wall portion  5   c , the back wall portion  5   e , and the like form a housing  5   i  of the printing apparatus  5 , and the left wall portion  5   d  serves as the cover member that covers an opening  5   j  formed in the housing  5   i . The left wall portion  5   d  may be referred to as the cover member  5   d  hereinafter. In addition, in this embodiment, the printing apparatus  5  includes a restricting mechanism  80  (see  FIGS. 10 and 11 , and the like) capable of restricting the opening operation of the cover member  5   d  and releasing the restriction. 
     The printing apparatus  5  includes a conveyance unit  20 , the printing unit  30 , the first drying promotion unit  40 , the second drying promotion unit  50 , a correction unit  60 , and an exhaust unit  70 . 
     &lt;Conveyance Unit&gt; 
     The conveyance unit  20  is a mechanism that conveys a sheet along the conveyance path RT. In this embodiment, the conveyance path RT is a path which has the opening  5   f  as an upstream end and the opening  5   g  as a downstream end and on which the sheet is conveyed. The conveyance path RT includes main paths RT 1  and RT 2 , a switch-back path RT 3 , and an inverting path RT 4 . The main paths RT 1  and RT 2  are paths from the opening  5   f  to the opening  5   g  via an intermediate point M 1 . The main path RT 1  is a path from the opening  5   f  to the intermediate point M 1 , and the main path RT 2  is a path from the intermediate point M 1  to the opening  5   g . The main paths RT 1  and RT 2  are paths on which the sheet is conveyed leftward→upward→rightward, and the sheet passes through the printing unit  30 →first drying promotion unit  40 →second drying promotion unit  50 →correction unit  60 . For one-sided print of printing on only one surface of the sheet, the sheet is conveyed through the main paths RT 1  and RT 2 . 
     The switch-back path RT 3  and the inverting path RT 4  are paths on which the sheet is conveyed after printing on one surface for double-sided print of printing on both surfaces of the sheet. The switch-back path RT 3  forms a path from the intermediate point M 1 , which is different from the main path RT 2 . The inverting path RT 4  is a path from the intermediate point M 1  to a midway joining point M 2  on the main path RT 1 . The sheet is inverted via the inverting path RT 4 , and is returned to the main path RT 1  again. 
     When referring to the downstream side and the upstream side in the following description, the conveyance direction of the sheet on the conveyance path RT is set as a reference. 
     The conveyance unit  20  includes a driving mechanism that applies a conveying force to the sheet, and a guide that guides conveyance of the sheet along the conveyance path RT, and  FIG. 2  shows part of the conveyance unit  20 . The driving mechanism includes a plurality of conveyance rollers  21  driven by a driving source such as a motor. For each conveyance roller  21 , a driven roller or a spur is arranged to face it. The sheet is conveyed while being nipped between each conveyance roller  21  and its corresponding driven roller or spur. The spur is arranged to contact a printing surface in a region on the downstream side with respect to the printing unit  30  in order to retain the quality of a printed image. The guide includes guide members  22  to  24 . The guide member  24  is supported by the left wall portion  5   d . Part of the conveyance path RT is formed between the guide members  23  and  24  and part of the main path RT 1  is formed between the guide members  22  and  24 . 
     The conveyance unit  20  includes path switching units  25  and  26 . The path switching units  25  and  26  are units that switch the guiding path of the sheet, and are operated by a driving source such as an electromagnetic solenoid or a motor. For one-sided print, the path switching units  25  and  26  guide the sheet from the main path RT 1  to the main path RT 2 . For double-sided print, the path switching units  25  and  26  guide the sheet from the main path RT 1  to the switch-back path RT 3 , and guide the switched-back sheet to the inverting path RT 4 .  FIG. 3  shows the path switching mode of the path switching units  25  and  26 . The path switching units  25  and  26  each include a pivotable flap, and switch the path by the positions of the flaps. The positions indicated by solid lines are those for one-sided print, and the positions indicated by broken lines are those for double-sided print. 
     &lt;Printing Unit&gt; 
     Referring back to  FIG. 2 , the printing unit  30  includes printheads  31 , and each printhead  31  is an inkjet head that forms an image (ink image) by discharging ink to a sheet. Inks to be discharged by the printheads  31  are reserved in a plurality of ink reservoirs T. The ink reservoirs T are provided for the respective kinds of inks. The kinds of inks are, for example, yellow, magenta, cyan, and black as kinds of colors. 
     The printheads  31  are provided for the respective kinds of inks. In this embodiment, each printhead  31  is a full-line head extended in the Y direction, and nozzles are arrayed within a range where they cover the width of an image printing area of a sheet having a usable maximum size. Each printhead includes a lower surface facing the sheet via a minute gap (for example, several mm), and the lower surface forms an ink discharge surface with the opened nozzle. 
     Each nozzle includes a discharge element. The discharge element is, for example, an element that generates a pressure in the nozzle and discharges ink in the nozzle, and the technique of a known inkjet head is applicable. Examples of the discharge element are an element that discharges ink by causing film boiling in ink with an electrothermal transducer and forming a bubble, an element that discharges ink by an electromechanical transducer, and an element that discharges ink by using static electricity. The discharge element that uses the electrothermal transducer can be used to perform high-speed and high-density printing. 
     Note that the printing unit  30  may be a serial-type printing unit in which printheads mounted on a carriage execute printing by reciprocally moving in the width direction of a sheet. The number of kinds of discharged inks may be one, for example, only black ink may be discharged. As the print mode of the printing unit  30 , a print mode of a single ink or a print mode of a plurality of kinds of inks can be selected. Each ink may mainly contain a coloring material (dye or pigment) and a solvent component. As a solvent component, a water-based material can be used. As a dye, for example, a water-soluble dye represented by a direct dye, an acid dye, a basic dye, a reactive dye, an edible pigment, or the like is preferable. However, any dye may be used as long as an image that satisfies a fixing property, color development, sharpness, stability, light resistance, and other required properties in combination of the print medium is obtained. As a pigment, carbon black or the like is preferable. Any of a method using a pigment and a dispersant, a method using a self-dispersion type pigment, and a method of performing microencapsulation can be used. Furthermore, ink can be used by adding, as appropriate, various additives such as a solvent component, a solubilizer, a viscosity modifier, a surfactant, a surface tension regulator, a pH adjuster, and a resistivity modifier. 
     &lt;Drying Promotion Unit&gt; 
     A sheet on which an image has been printed by the printing unit  30  may be expanded due to the liquid of the ink, and may be waved. Such sheet causes a paper jam in the printing apparatus  5  or degrades stackability/alignment in the post processing apparatus  3 . By promoting drying of the sheet, it is possible to suppress expansion of the sheet caused by the liquid of the ink. The printing apparatus  5  according to this embodiment includes the plurality of drying promotion units, that is, the first drying promotion unit  40  and the second drying promotion unit  50  of different sheet drying methods. 
     The first drying promotion unit  40  is a unit that is arranged on the downstream side with respect to the printing unit  30  and promotes drying of the sheet by blowing warm air to the sheet without contacting the sheet. The structure of the first drying promotion unit  40  will be described with reference to  FIGS. 2 and 3 . 
     The first drying promotion unit  40  includes a hollow body  41  that defines the internal space, and a fan  42  and heating elements  43  all of which are arranged in the hollow body  41 . The hollow body  41  includes an air intake port  41   a  in a right portion. A wall portion  41   b  that forms the left portion of the hollow body  41  is a guide wall portion also serving as a sheet conveyance guide, and is extended in the Y direction to cover the width of a sheet having the maximum size. The guide wall portion  41   b  has a C-shaped sectional shape (a section on an X-Z plane), and includes a wall surface facing the guide members  22  to  24 . Part of the conveyance path RT is formed between the wall surface and the guide members  22  to  24 , and the intermediate point M 1  is also set. In the guide wall portion  41   b , a number of warm air blowing holes N communicating with the internal space of the hollow body  41  are formed. 
     The fan  42  is an electric fan that uses a motor as a driving source, and is, for example, a sirocco fan. The fan  42  introduces air from the air intake port  41   a  into the hollow body  41 . The pressure in the hollow body  41  increases by the introduced air, and the air in the hollow body  41  is blown out of the hollow body  41  from the blowing holes N. One fan  42  may be provided or a plurality of fans  42  may be juxtaposed in the Y direction. 
     The heating elements  43  heat the air introduced by the fan  42  from the air intake port  41   a  into the hollow body  41 . In this embodiment, each heating element  43  is a rod-like heating element such as an infrared lamp heater, and is extended in the Y direction. The plurality of heating elements  43  are arrayed in the Z direction. The plurality of heating elements  43  are arranged between the fan  42  and the air intake port  41   a , and the air introduced from the air intake port  41   a  into the hollow body  41  is heated when it passes through the heating elements  43 . A temperature sensor  44  is provided in the first drying promotion unit  40 , and driving of the heating elements  43  is controlled in accordance with the detection result of the temperature sensor  44 . 
     With this arrangement, the first drying promotion unit  40  blows warm air from the blowing holes N, as indicated by an airflow represented by arrows in  FIG. 3 . This can heat the sheet passing through the conveyance path RT, and promote evaporation of a liquid contained in the ink image on the sheet, thereby promoting drying of the sheet. 
     The second drying promotion unit  50  is a thermal fixing unit that is arranged on the downstream side with respect to the first drying promotion unit  40  and promotes drying of the sheet by heating the sheet in contact with the image printing surface of the sheet. The structure of the second drying promotion unit  50  will be described with reference to  FIG. 2 . 
     The second drying promotion unit  50  includes a heater  51  and a roller  56 , which are extended in the Y direction to cover the width of a sheet having the maximum size. The heater  51  includes a support member  53  that supports a heating element  54 . The heating element  54  is, for example, a ceramic heater, and is extended in the Y direction. The temperature of the heating element  54  is detected by a temperature sensor  55  represented by a thermistor, and driving of the heating element  54  is controlled based on a detection result. 
     The support member  53  also supports a film  52 . The film  52  is formed in a cylindrical shape and extended in the Y direction. The film  52  is supported by the support member  53  to be rotatable about the support member  53 , and is interposed between the roller  56  and the heating element  54 . The film  52  is, for example, a single-layer film or composite layer film having a film thickness of 10 μm (inclusive) to 100 μm (inclusive). When the film  52  is a single-layer film, for example, PTFE, PFA, or FEP is used as a material. When the film  52  is a composite film, for example, it is a film with a layer structure that covers or coats a layer of polyimide, polyamide-imide, PEEK, PES, PPS, or the like with PTFE, PFA, FEP, or the like. 
     Note that the arrangement of the heater  51  is not limited to this, and may have, for example, a structure that includes a heating element such as a halogen heater in a hollow metal core and covers the periphery of the core with an elastic body such as a silicone rubber. 
     The roller  56  is formed by covering the periphery of a core  56   a  with an elastic body  56   b  such as a silicone rubber. The roller  56  is pressed against the heater  51  by a predetermined pressing force, and the roller  56  and the heater  51  form a nip portion. The roller  56  is rotated using a motor as a driving source, and the film  52  rotates together with the roller  56 . With this arrangement, the sheet is heated while being conveyed in the nip portion, thereby making it possible to promote drying of the sheet. 
     In this embodiment, the first drying promotion unit  40  and the second drying promotion unit  50  dry the sheet in two stages. However, only the second drying promotion unit  50  may be provided. 
     &lt;Correction Unit&gt; 
     The correction unit  60  is a mechanism that corrects the curvature (curl in this example) of a sheet. In this embodiment, the correction unit  60  includes a large-diameter driving roller  61  and a small-diameter driven roller  62 . The driving roller  61  is a roller obtained by covering the periphery of a core with an elastic body such as a silicone rubber. The driven roller  62  is a metal roller. The driving roller  61  and the driven roller  62  are in press contact with each other. When a sheet passes between the driving roller  61  and the driven roller  62 , these rollers can apply a pressure to the sheet to correct the curl of the sheet. The correction unit  60  can apply, to the sheet, a correction force in, for example, an upwardly-convex direction. In this case, the correction unit  60  can correct a sheet having a downwardly-convex curl to a flatter state. 
     &lt;Exhaust Unit&gt; 
     The exhaust unit  70  is a unit that exhausts the air in the printing apparatus  5  outside the apparatus. The printing apparatus  5  according to this embodiment includes the first drying promotion unit  40  and the second drying promotion unit  50 , which raise the temperature in the apparatus. In addition, these units operate to evaporate moisture of ink. When continuously printing on a number of sheets, the humidity in the apparatus may rise. A high humidity curves the sheet. The conveyance distance of the sheet from the second drying promotion unit  50  to the opening  5   g  is relatively long, and the sheet is conveyed within the upper space SP 2  where water vapor is readily retained. In the space SP 2 , the sheet may be exposed to a high-humidity atmosphere. The humidity in the apparatus can be lowered when the exhaust unit  70  exhausts the air in the space SP 2  outside the apparatus. 
     The exhaust unit  70  according to this embodiment has a structure that naturally exhausts the air in the space SP 2  by a plurality of exhaust ducts  71  to  73 . However, the exhaust unit  70  may forcibly exhaust the air in the apparatus by a fan or the like. The structure of the exhaust unit  70  will be described with reference to  FIGS. 2 to 4 .  FIG. 4  is a plan view showing the periphery of the exhaust unit  70 , and does not illustrate the upper wall portion  5   b.    
     The exhaust duct  71  is a tube member including an extended portion  71   a  extended in the Y direction and an extended portion  71   b  extended from the far end portion in the Y direction of the extended portion  71   a  to the right side in the X direction. The extended portion  71   a  is extended at a position lower than the main path RT 2  near a sheet discharge position in the second drying promotion unit  50 . The extended portion  71   a  is an air intake portion in which a plurality of slits serving as air intake ports are formed in the upper left portion and the bottom portion. For example, air warmed by the second drying promotion unit  50  can be introduced from the slit in the upper left portion, and warm air blown from the blowing holes N of the first drying promotion unit  40  can be introduced from the slit in the bottom portion. The extended portion  71   a  is extended across the back wall portion  5   e , and the far end portion in the Y direction of the extended portion  71   a  and the extended portion  71   b  are located outside (on the far side in the Y direction of) the space SP 2 . Note that the extended portion  71   a  may be extended at a position above the main path RT 2 . 
     The exhaust duct  72  is a tube member including an extended portion  72   a  extended in the Y direction, a collecting portion  72   b  extending rightward from the extended portion  72   a , and an extended portion  72   c  extended from the right end portion of the collecting portion  72   b  to the far side in the Y direction. The extended portion  72   a  is extended at a position above the main path RT 2  near the sheet discharge position in the second drying promotion unit  50 . The bottom portion of the extended portion  72   a  is open to form an air intake port from which, for example, air warmed by the second drying promotion unit  50  or water vapor in the space SP 2  is introduced. The extended portion  72   a  protrudes above the upper wall portion  5   b  across the upper wall portion  5   b.    
     The collecting portion  72   b  has, in a planar view, a triangular shape which is wide on the side of the extended portion  72   a , and the overall collecting portion  72   b  is located above the upper wall portion  5   b . The collecting portion  72   b  collects, to the central portion in the Y direction in the right end portion, the air introduced into the extended portion  72   a . The collected air flows into the extended portion  72   c . The overall extended portion  72   c  is also located above the upper wall portion  5   b , and the extended portion  72   c  is partially bended and extended on the far side of the back wall portion  5   e . On the far side of the back wall portion  5   e , the extended portion  71   b  of the exhaust duct  71  is connected to the extended portion  72   c  of the exhaust duct  72 , and the internal spaces of these portions communicate with each other. The extended portion  72   c  is connected to the exhaust duct  73 . 
     The exhaust duct  73  is an exhaust member that is extended in the X direction and is open to the far side in the Y direction. The opening of the exhaust duct  73  faces a cover  8  that forms the exterior of the main body apparatus  2  on the back side. In the cover  8 , a number of slits (louver)  8   a  are formed, and the air flowing into the exhaust duct  73  is exhausted out of the apparatus from the back side of the main body apparatus  2  through the slits  8   a.    
     &lt;Control Unit&gt; 
     The control system of the main body apparatus  2  will be described.  FIG. 5  is a block diagram of a control unit  9  of the main body apparatus  2 . The control unit  9  includes a processing unit  10 , a storage unit  11 , a reading controller  13 , an image processing unit  14 , a head controller  15 , an engine controller  16 , a drying controller  17 , a display controller  18 , and a restricting mechanism controller  19 . The processing unit  10  is a processor represented by a CPU (Central Processing Unit), and comprehensively controls the operations of the units of the main body apparatus  2 . The storage unit  11  is, for example, a storage device such as a ROM or a RAM. The storage unit  11  stores a program to be executed by the processing unit  10 , and permanent data (for example, data concerning a sheet type stored in each cassette  6   a ) necessary for various operations of the main body apparatus  2 . The storage unit  11  serves as a work area of the processing unit  10  or a temporary storage area of various reception data to store various setting data. 
     The reading controller  13  controls the reading apparatus  4 . The image processing unit  14  performs image processing of image data to be processed by the main body apparatus  2 . The color space (for example, YCbCr) of input image data is converted into a standard RGB color space (for example, sRGB). Print data obtained by these image processes is stored in the storage unit  11 . The head controller  15  controls driving of the printing unit  30  in accordance with the print data based on a control command received from the processing unit  10 . For example, the engine controller  16  controls conveyance of a sheet. The drying controller  17  controls driving of the first drying promotion unit  40  and the second drying promotion unit  50 . The display controller  18  controls display of information by the display unit  7   a . The restricting mechanism controller  19  controls the restricting mechanism  80 . Each of these controllers includes a processor such as a CPU, a storage device such as a RAM or a ROM, and an interface with an external device. 
     An I/O  12  is an interface (I/F) for connecting the control unit  9  to a host apparatus H and the post processing apparatus  3 , and is a local I/F or a network I/F. The host apparatus H is an apparatus serving as a supply source of image data for causing the printing apparatus  5  to perform a printing operation. The host apparatus H may be a general-purpose or dedicated computer, or a dedicated image apparatus including an image reader, such as image capture, a digital camera, or a photo storage. 
     Operation Example 
     An example of the printing operation of the printing apparatus  5  under the control of the control unit  9  will be described with reference to  FIGS. 6 to 9 . First, an operation when printing an image on one surface of a sheet will be described with reference to  FIGS. 6 and 7 . When printing an image on one surface of a sheet, the path switching units  25  and  26  are set at the positions (the positions indicated by solid lines in  FIG. 3 ) for one-sided print. The heating elements  43  of the first drying promotion unit  40  and the heating element  54  of the second drying promotion unit  50  are maintained in advance at a predetermined temperature. 
     A state ST 1  shown in  FIG. 6  indicates a state in which a sheet P fed from the feeding apparatus  6  has been conveyed by the conveyance unit  20  to the printing unit  30  on the main path RT 1 , and printing by the printing unit  30  has started. The printing unit  30  prints an image by discharging ink to the sheet P as indicated by an arrow. The sheet P is conveyed toward the first drying promotion unit  40 . The first drying promotion unit  40  starts to operate, and blows warm air to the conveyed sheet P, as indicated by a state ST 2  shown in  FIG. 6 . The warm air promotes drying of the sheet P wet with ink. 
     The sheet P is further conveyed toward the second drying promotion unit  50  on the main path RT 2 . The second drying promotion unit  50  starts to operate, the roller  56  rotates, as indicated by a state ST 3  shown in  FIG. 7 , and the sheet P is heated by the heater  51  while being conveyed. Drying of the sheet P is further promoted. 
     As indicated by a state ST 4  shown in  FIG. 7 , the sheet P is further conveyed toward the correction unit  60  on the main path RT 2 . The correction unit  60  starts to operate, and the sheet P is discharged from the opening  5   g  to the post processing apparatus  3  while the curl of the sheet P is corrected. 
     An operation when printing images on both surfaces of a sheet will be described next with reference to  FIGS. 8 and 9 . A state ST 11  shown in  FIG. 8  indicates a state in which the sheet P fed from the feeding apparatus  6  has been conveyed by the conveyance unit  20  to the printing unit  30  on the main path RT 1 , and the printing unit  30  has started printing. The printing unit  30  prints an image by discharging ink to the front surface of the sheet P, as indicated by an arrow. The path switching unit  26  is set at the position (the position indicated by the broken line in  FIG. 3 ) for double-sided print. 
     The sheet P is conveyed toward the first drying promotion unit  40 . The first drying promotion unit  40  starts to operate, and blows warm air to the conveyed sheet P, as indicated by a state ST 12  shown in  FIG. 8 . The warm air promotes drying of the sheet P wet with ink. The path switching unit  26  guides the sheet P not to be conveyed to the second drying promotion unit  50  but to be conveyed to the switch-back path RT 3 . When the trailing edge of the sheet P passes through the position of the path switching unit  25 , the path switching unit  25  is set at the position for double-sided print. Subsequently, the conveyance unit  20  conveys the sheet P in a reverse direction on the switch-back path RT 3  (switch-back conveyance). 
     The path switching unit  25  guides the sheet P to be conveyed to the inverting path RT 4 , as indicated by a state ST 13  shown in  FIG. 9 . Then, the sheet P is returned to the main path RT 1 , as indicated by a state ST 14  shown in  FIG. 9 . The path switching unit  25  is set at the position (the position indicated by the solid line in  FIG. 3 ) for one-sided print. The printing unit  30  prints an image by discharging ink to the back surface of the sheet P, as indicated by an arrow. Operations after that are the same as those in the states ST 2  to ST 4  for one-sided print. 
     &lt;Arrangement of Cover Member&gt; 
       FIG. 10A  is a schematic view showing the arrangement of the cover member  5   d  and the restricting mechanism  80 , and shows a closed state in which the cover member  5   d  is closed.  FIG. 10B  is a schematic view showing the arrangement of the cover member  5   d  and the restricting mechanism  80 , and shows the printing apparatus  5  in the closed state when viewed from above.  FIG. 10C  is a schematic view showing the arrangement of the cover member  5   d  and the restricting mechanism  80 , and shows an open state in which the cover member  5   d  is opened.  FIG. 10D  is a schematic view showing the arrangement of the cover member  5   d  and the restricting mechanism  80 , and shows the printing apparatus  5  in the open state when viewed from above. Each of  FIGS. 10A and 10C  is a view of the printing apparatus  5  when viewed from the left side in  FIG. 1 . Note that in  FIGS. 10A to 10D , some components such as the guide members  22  to  24  are not illustrated in order to make the drawings easy to see. 
     In this embodiment, the left side of the cover member  5   d  is pivotably supported by the housing  5   i  when viewed from the front, and formed to be opened to the left with respect to the housing  5   i . When the cover member  5   d  is opened, the second drying promotion unit  50  is exposed through the opening  5   j . Therefore, the second drying promotion unit  50  can be removed from the housing  5   i  via the opening  5   j.    
     Note that in this embodiment, although omitted in  FIGS. 10C and 10D , the guide members  23  and  24  are provided such that the second drying promotion unit  50  can be exposed when viewed from the opening  5   j  side at the time of opening the cover member  5   d . For example, the guide member  24  may be supported by the cover member  5   d . Alternatively, for example, the guide member  23  may be supported so as to be pivotable with respect to the housing  5   i , and the entire second drying promotion unit  50  may be exposed by pivoting the guide member  23 . With this arrangement, it is possible to perform jam clearance near the second drying promotion unit  50 , and attach/detach the second drying promotion unit  50 . 
     The mode of opening/closing the cover member  5   d  can be appropriately designed. For example, the cover member  5   d  may be opened to the right, opened vertically, or the like. Further, the cover member  5   d  may be removable from the housing  5   i , or may be a slide type. 
     &lt;Arrangement of Restricting Mechanism&gt; 
       FIG. 11A  is a sectional view taken along a line I-I in  FIG. 10A , and shows a state in which a displacement member  81  is set in a restriction position, and  FIG. 11B  is a sectional view showing a state in which the displacement member  81  is set in a release position. The printing apparatus  5  includes the restricting mechanism  80  for restricting the opening operation of the cover member  5   d , that is, for locking the cover member  5  in the closed state. In this embodiment, the restricting mechanism  80  includes the displacement member  81 , an actuator  82  that drives the displacement member  81 , and an engaging portion  83  that engages with the displacement member  81 . 
     The displacement member  81  is a member provided on the housing  5   i  side and displaceable between the restriction position for restricting the opening operation of the cover member  5   d  and the release position for releasing the restriction. In this embodiment, the displacement member  81  has a rod-like shape extending vertically, and is vertically displaced between the restriction position and the release position. 
     The actuator  82  is provided on the housing  5   i  side. For example, the actuator  82  is an electric motor. As an example, the restricting mechanism  80  includes a rack and pinion mechanism, and this converts the rotational movement of the electric motor into the translational movement of the displacement member  81 . 
     Another known mechanical restricting mechanism can also be employed as the restricting mechanism  80 . Further, not only the mechanical mechanism but also an electromagnet or the like may be used to switch the restricting state and the release state. However, in this embodiment, by restricting the opening operation with the mechanical component, it is possible to more reliably restrict the pivot movement of the cover member  5   d.    
     The engaging portion  83  engages with the displacement member  81  in a state in which the displacement member  81  is set in the restriction position, thereby restricting the opening operation of the cover member  5   d . In this embodiment, the engaging portion  83  is provided on the cover member  5   d  side and, for example, is a concave portion corresponding to the shape of the displacement member  81 . 
     When the displacement member  81  is set in the restriction position (a position  1101 ) as shown in  FIG. 11A , the opening operation of the cover member  5   d  is restricted in the closed state in which the cover member  5   d  is kept closed ( FIG. 10A ). On the other hand, when the displacement member  81  is set in the release position (a position  1102 ) as shown in  FIG. 11B , the restriction of the opening operation of the cover member  5   d  is released, so that the cover member  5   d  can pivot with respect to the housing  5   i  ( FIG. 10C ). 
     PROCESSING EXAMPLES OF RESTRICTING MECHANISM CONTROLLER 
     When jam clearance occurs or when the second drying promotion unit  50  is to be inserted or removed, the user performs the operation while opening the cover member  5   d , but this causes the second drying promotion unit  50  and its surrounding members having reached a high temperature after operation to be exposed. Therefore, in this embodiment, the restricting mechanism controller  19  controls the restricting mechanism  80  based on the temperature condition of the second drying promotion unit  50 . With this operation, it is possible to suppress exposure of the second drying promotion unit  50  and its surrounding members in a high temperature state. Processing examples of the restricting mechanism controller  19  will be described below. 
     Processing Example 1 
       FIG. 12A  is a flowchart illustrating an example of processing executed by the restricting mechanism controller  19 .  FIG. 12B  is a flowchart illustrating an example of processing in step S 12  of  FIG. 12A . These flowcharts are implemented by, for example, the CPU loading a program stored in the ROM into the RAM and executing it in the restricting mechanism controller  19 . 
     In step S 11 , the restricting mechanism controller  19  checks the temperature condition of the second drying promotion unit  50 . In this embodiment, the restricting mechanism controller  19  acquires the temperature of the second drying promotion unit  50  from a detection result of the temperature sensor  55 . However, the restricting mechanism controller  19  may check the temperature condition of the second drying promotion unit  50  from its output, heating time, control condition of the warm-up control at startup, and the like of the second drying promotion unit  50 . That is, the temperature condition is not limited to the direct temperature information acquired from the temperature sensor or the like, but may be indirect temperature information estimated from another information. 
     In step S 12 , the restricting mechanism controller  19  controls the restricting mechanism  80  based on the temperature condition acquired in step S 11 , and the flowchart is terminated. An example of processing in step S 12  will be described with reference to  FIG. 12B . 
     In step S 121 , the restricting mechanism controller  19  determines whether the temperature as the temperature condition acquired in step S 11  exceeds a predetermined threshold value. If the temperature exceeds the predetermined threshold value, the process advances to step S 122 ; otherwise, the process advances to step S 123 . The threshold temperature may be set within a range of, for example, 50° to 60°. More specifically, the threshold temperature may be, for example, 55°. Note that when the restricting mechanism controller  19  acquires, as the temperature condition, information such as the output, heating time, control condition of the warm-up control at startup of the second drying promotion unit  50  in step S 11 , the process may advance to step S 122  if the acquired information satisfies a predetermined condition for restricting the opening operation. 
     In step S 122 , the restricting mechanism controller  19  restricts the opening operation of the cover member  5   d . That is, the restricting mechanism controller  19  controls the actuator  82  to displace the displacement member  81  from the release position to the restriction position. Thus, the opening operation of the cover member  5   d  is restricted. Note that if Yes in step S 121 , the restricting mechanism controller  19  may check the current position of the displacement member  81  before executing the processing in step S 122 , and if the displacement member  81  is already in the restriction position, the processing in step S 122  may be omitted. 
     In step S 123 , the restricting mechanism controller  19  releases the restriction of the opening operation of the cover member  5   d . That is, the restricting mechanism controller  19  controls the actuator  82  to displace the displacement member  81  from the restriction position to the release position. Thus, the restriction of the opening operation of the cover member  5   d  is released. Note that if No in step S 121 , the restricting mechanism controller  19  may check the current position of the displacement member  81  before executing the processing in step S 123 , and if the displacement member  81  is already in the release position, the processing in step S 123  may be omitted. 
     According to this processing example, the opening operation of the cover member  5   d  is restricted in accordance with the temperature condition of the second drying promotion unit  50 , so that it is possible to suppress exposure of the heading device in a high temperature state. 
     Processing Example 2 
       FIG. 13A  is a flowchart illustrating an example of processing executed by the restricting mechanism controller  19 , and  FIG. 13B  is a flowchart illustrating an example of processing executed by the display controller  18 . This processing example shows a processing example in a case of, if the opening operation of the cover member  5   d  is restricted, displaying information about the restriction on the display unit  7   a  included in the operation unit  7 .  FIG. 13C  is a view showing an example of display by the display unit  7   a.    
     Steps S 21  and S 22  are processing operations similar to those in steps S 11  and S 12 , respectively. In step S 23 , the restricting mechanism controller  19  notifies the display controller  18  of the state of restriction of the restricting mechanism  80 , and terminates the processing. In this embodiment, the restricting mechanism controller  19  notifies the display controller  18  whether the restricting mechanism  80  is in a restricting state or in a release state. 
     Processing by the display controller  18  will be described with reference to  FIG. 13B . In step S 25 , the display controller  18  checks the state of the restricting mechanism  80  based on the notification from the restricting mechanism controller  19  in step S 23 . If the restricting mechanism  80  is in the restricting state, that is, if the displacement member  81  is set in the restriction position, the display controller  18  advances to step S 26 . On the other hand, if the restricting mechanism  80  is in the release state, that is, if the displacement member  81  is set in the release position, the display controller  18  advances to step S 27 . 
     In step S 26 , the display controller  18  displays, on the display unit  7   a , information indicating that the opening operation of the cover member  5   d  is restricted by the restricting mechanism  80 .  FIG. 13C  shows an example of display on the display unit  7   a . As an example, the display controller  18  displays a message M such as “the cover is locked” on the display unit  7   a . Thus, the information indicating that the opening operation is restricted is informed to the user. Note that if it is confirmed in step S 25  that the restricting mechanism  80  is in the restricting state, the display controller  18  may check the current display condition of the display unit  7   a  before advancing to the processing in step S 26 , and if the message is already being displayed, the processing in step S 26  may be omitted. Alternatively, the display controller  18  may check the current display condition of the display unit  7   a  before advancing to the processing in step S 26 , and if the message is already being displayed, it may execute processing for continuing the display of the message. 
     In step S 27 , the display controller  18  terminates the display, on the display unit  7   a , of the information indicating that the opening operation of the cover member  5   d  is restricted by the restricting mechanism  80 . Note that if it is confirmed in step S 25  that the restricting mechanism  80  is in the release state, the display controller  18  may check the current display condition of the display unit  7   a  before advancing to the processing in step S 27 , and if the information is not being displayed, the processing in step S 27  may be omitted. 
     According to this processing example, the information indicating that the opening operation of the cover member  5   d  is restricted is displayed, so that the user can more readily recognize the restriction of the opening operation. Therefore, when the user tries to open the cover member  5   d  for jam clearance, replacement of the second drying promotion unit  50 , or the like, the user can recognize that the opening operation is restricted, so that the user convenience is improved. 
     Processing Example 3 
       FIG. 14  is a flowchart illustrating an example of processing executed by the display controller  18 . This processing example shows a processing example in a case of, if the opening operation of the cover member  5   d  is being released, displaying information indicating that the opening operation is not being restricted on the display unit  7   a  of the operation unit  7 . 
     Steps S 31  and S 32  are processing operations similar to those in steps S 25  and S 26 , respectively. In step S 33 , the display controller  18  displays, on the display unit  7   a , information indicating that the opening operation of the cover member  5   d  is being released by the restricting mechanism  80 . As an example, the restricting mechanism controller  19  displays a message such as “the cover is unlocked” on the display unit  7   a . Note that if it is confirmed in step S 31  that the restricting mechanism  80  is in the release state, the display controller  18  may check the current display condition of the display unit  7   a  before advancing to the processing in step S 33 , and if the message is already being displayed, the processing in step S 33  may be omitted. Alternatively, the display controller  18  may check the current display condition of the display unit  7   a  before advancing to the processing in step S 33 , and if the message is already being displayed, it may execute processing for continuing the display of the message. 
     According to this processing example, the information indicating that the opening operation of the cover member  5   d  is not being restricted is displayed, so that the user can more readily recognize the state of restriction of the cover member  5   d . Therefore, when the user tries to open the cover member  5   d  for jam clearance, replacement of the second drying promotion unit  50 , or the like, the user can recognize the state of restriction of the opening operation of the cover member  5   d , so that the user convenience is improved. 
     ARRANGEMENT EXAMPLE OF DRYING PROMOTION UNIT 
     Arrangement Example 1 
       FIG. 15A  is a front view showing an arrangement example of the second drying promotion unit  50 , and  FIG. 15B  is a sectional view taken along a line II-II in  FIG. 15A . Note that  FIG. 15A  is a schematic view of the second drying promotion unit  50  when viewed from the opening  5   j  side. In  FIG. 15B , for the sake of simplicity, hatching indicating the sectional view is appropriately omitted (this also applies to  FIGS. 16B and 17B  to be described later). 
     In this arrangement example, the second drying promotion unit  50  is provided so as to be attachable/detachable to/from attachment portions  58  provided on the housing  5   i  side at the time of attachment. The attachment portion  58  is, for example, a frame member supported by the housing  5   i . In the example shown in  FIG. 15A , the second drying promotion unit  50  is attached to the housing  5   i  so as to be sandwiched between two frame members which are vertically spaced apart from each other. 
     The second drying promotion unit  50  includes an accommodation portion  57  that accommodates the heater  51  and the roller  56 , which are extended in the widthwise direction crossing the conveyance direction of the sheet P, and the like. The accommodation portion  57  is formed by, for example, a resin member or the like so as to cover the heater  51 , the roller  56 , and the like. In addition, an opening (not shown) serving as the conveyance path of the print medium is provided in each of a front surface  578  and a back surface  579  of the accommodation portion  57 . 
     Further, a plurality of grip portions  57 A and  57 B spaced apart from each other are provided in the accommodation portion  57 . The user can remove the second drying promotion unit  50  from the housing  5   i  by gripping the grip portions  57 A and  57 B and pulling them out in the X direction. Since the plurality of grip portions ( 57 A and  57 B) are provided, the user can grip the second drying promotion unit  50 , which is a heavy load, at the plurality of portions, so that the user can more stably attach and detach the second drying promotion unit  50 . 
     The arrangement of the plurality of grip portions  57 A and  57 B can be appropriately designed. For example, the plurality of grip portions  57 A and  57 B may be provided with a center of gravity G of the second drying promotion unit  50  therebetween. With this arrangement, the second drying promotion unit  50  is less likely to incline when the user grips the second drying promotion unit  50 , so that the user can more stably attach and detach the second drying promotion unit  50 . In this embodiment, the plurality of grip portions  57 A and  57 B are provided on the both end portion sides of the roller  56 . Thus, it is possible to more stably attach and detach the second drying promotion unit  50  which is long in the widthwise direction. 
     Note that the number of the grip portions is not limited to two, and may be three or more. Further, in this embodiment, as shown in  FIG. 15B , the grip portions  57 A and  57 B are concave portions formed in the accommodation portion  57 . However, another shape can also be employed as the grip portion. For example, each grip portion may have a collar-like shape protruding from the accommodation portion  57  to the front side (X direction) or the like. 
     Arrangement Example 2 
       FIG. 16A  is a front view showing another arrangement example of the second drying promotion unit  50 , and a schematic view showing a case in which the grip portion is in a retracted state.  FIG. 16B  is a sectional view taken along a line III-III in  FIG. 16A .  FIG. 17A  is a schematic front view showing a case in which the grip portion of the second drying promotion unit  50  shown in  FIG. 16A  is in an extended state, and  FIG. 17B  is a sectional view taken along a line IV-IV in  FIG. 17A . Note that components similar to those of the second drying promotion unit  50  in &lt;Arrangement Example 1&gt; have the same reference numerals, and a description thereof will be omitted. 
     In this arrangement example, the second drying promotion unit  50  is provided with a main body  50 A which includes the heater  51 , the roller  56 , and the accommodation portion  57  that accommodates the heater  51  and the roller  56 , and a grip portion  57 C which is pivotable with respect to the main body  50 A. In this arrangement example, the grip portion  57 C pivots between the extended state ( FIG. 17A ) in which it stands upright with respect to the main body  50 A and the retracted state ( FIG. 16A ) in which it lies down with respect to the main body  50 A. 
     The grip portion  57 C is pivotably supported on the upper surface of the accommodation portion  57 . Further, the grip portion  57 C includes a grip member  571  which is gripped by the user, and connection members  572  each connecting the grip member  571  and a pivot shaft  573 . Note that this supporting mode of the grip portion  57 C is merely an example, and another supporting mode can also be employed. For example, the grip portion  57 C may be pivotably supported at the both side surfaces of the accommodation portion  57 . 
     As shown in  FIGS. 16A and 16B , in this arrangement example, the second drying promotion unit  50  is provided such that the grip portion  57 C in the retracted state is exposed upon opening the cover member  5   d . More specifically, the second drying promotion unit  50  is provided such that the grip member  571  of the grip portion  57 C is exposed. Thus, the user can grip the grip member  57 C and pull out the second drying promotion unit  50 . In addition, since the grip member  57 C lies down in the retracted state, the second drying promotion unit  50  can be accommodated more compactly. 
     When the second drying promotion unit  50  is pulled out from the attachment portions  58 , the grip portion  57 C is pivoted by the weight of the main body  50 A, so that the grip portion  57 C is set in the extended state ( FIG. 17A ). Since the grip portion  57 C stands upright in the extended state, the user can hang and hold the second drying promotion unit  50 . 
     Further, in this arrangement example, the pivot shaft of the grip portion  57 C is provided above the center of gravity G of the main body  50 A. In addition, the pivot shaft of the grip portion  57 C is provided behind (on the side far from the opening  5   j ) the center of gravity G of the main body  50 A in the pull-out direction (X direction). Thus, the inclination of the main body  50 A upon being pulled out can be further suppressed. 
     Note that it is also possible to employ an arrangement in which the grip portions  57 A and  57 B of arrangement example 1 and the grip portion  57 C of this arrangement example are used together. 
     Arrangement Example 3 
       FIG. 18  is a front view showing another arrangement example of the second drying promotion unit  50 . In this arrangement example, alignment portions  59 A for performing alignment upon attaching the second drying promotion unit  50  to attachment portions  59  are provided. On the other hand, alignment portions  57 D are provided on the accommodation portion  57  of the second drying promotion unit  50 . In this arrangement example, the alignment portions  59 A and  57 D are triangle marks. By aligning the vertical positions of the alignment portions  59 A and  57 D, the second drying promotion unit  50  can be aligned with the attachment portions  59 . 
     The mark shapes of the alignment portions  59 A and  57 D can be appropriately designed. For example, horizontal bars, or the like may be used. In addition, it is also possible to employ an arrangement in which the alignment portions  59 A are provided only on the attachment portions  59  and, for example, the upper or lower end of the accommodation portion  57  is aligned with the alignment portion  59 A. Further, as another mode of the alignment portions  59 A, it is also possible to employ, for example, an arrangement in which guide members protruding from the attachment portions  59  to the side on which the second drying promotion unit  50  is attached are provided. 
     Arrangement Example 4 
       FIG. 19A  is a front view showing another arrangement example of the second drying promotion unit  50 , and  FIGS. 19B to 19D  are views (top views) each taken in the direction of an arrow A in  FIG. 19A  and showing an example of openings formed in the second drying promotion unit  50 . Note that the reference numerals of the openings are partially omitted in  FIGS. 19B to 19D . 
     The second drying promotion unit  50  is configured to surround the heating element  51 , which is the heat source, with the accommodation portion  57 . Accordingly, heat is readily retained in the accommodation portion  57 , and it may take time for the second drying promotion unit  50  to fall to a temperature at which it can be removed. Therefore, in this embodiment, openings that make the inside and the outside of the accommodation portion  57  communicate with each other are formed. Thus, the heat inside the accommodation portion  57  is dissipated, and the temperature decrease of the second drying promotion unit  50  can be further promoted. 
     Examples of the openings include slit-shaped openings  575  ( FIG. 19B ), punch holes  576  ( FIG. 19C ), lattice-shaped openings  577  ( FIG. 19D ), or the like formed in the upper surface of the accommodation portion  57 . For example, these openings may be formed in a size that does not allow the user&#39;s finger to enter. With this arrangement, it is possible to promote the temperature decrease of the second drying promotion unit  50  while preventing the user from touching the roller  56  or the like in a high temperature state. In this arrangement example, the openings are formed in the upper surface of the accommodating portion  57 , but they may be formed in the side surface, the lower surface, or the like. 
     Another Embodiment 
     In the above-described embodiment, the second drying promotion unit  50  has been described as an example, but the present invention can also be applied to a unit such as the first drying promotion unit  40  that can reach a high temperature. The constituent members of the first drying promotion unit  40  can also reach a hot temperature due to warm air, and in that case, it is desirable to prevent the user from touching them. Therefore, the opening operation of the cover member  5   d  may be restricted if the first drying promotion unit  40  is considered to be at a high temperature. 
     The temperature threshold value for restricting the opening operation of the cover member  5   d  may be different from the temperature threshold value for releasing the restriction. That is, the temperature threshold value may have hysteresis. For example, there may be a temperature gradient in the accommodation portion  57 , so that there may be a portion in the accommodation portion  57  where the actual temperature is higher than the temperature detected by the temperature sensor  55 . For example, by setting the temperature threshold value for releasing the restriction lower than the temperature threshold value for restricting the opening operation, it is possible to suppress the exposure of the second drying promotion unit  50  in the high temperature state. 
     In addition, the situation may be limited in which information indicating that the opening operation is being restricted or information indicating that the opening operation is not being restricted is displayed on the display unit  7   a . For example, the restricting mechanism controller  19  may instruct the operation unit  7  to display the information only when the user is likely to open the cover member  5   d , such as when a jam has occurred or when the user is prompted to replace the second drying promotion unit  50 . Further, in the above-described embodiment, the above-described information related to the restriction of opening operation is notified to the user by display on the display unit  7   a , but another mode can also be employed as the mode of notification. For example, the apparatus main body  2  may include a loudspeaker or the like, and the loudspeaker may notify the above-described information by audio output. Furthermore, for example, the above-described information may be transmitted to a terminal owned by the user by wireless communication or the like, and the above-described information may be displayed on the terminal owned by the user. 
     Other Embodiments 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2019-164785, filed Sep. 10, 2019, which is hereby incorporated by reference herein in its entirety.