Patent Publication Number: US-11040532-B2

Title: Inkjet printer

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority benefit of Japanese Patent Application No. 2018-115638, filed on Jun. 18, 2018. 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 an inkjet printer. 
     DESCRIPTION OF THE BACKGROUND ART 
     The inkjet printer includes a head cap that covers an ejection surface of an inkjet head (lower surface where an ink ejection port is provided) when performing maintenance on the inkjet head, for example, when purging, flushing, or suctioning ink in the nozzle (e.g., Japanese Unexamined Patent Publication No. 2018-69713 (Patent Literature 1)).
     Patent Literature 1: Japanese Unexamined Patent Publication No. 2018-69713   

     SUMMARY 
     The inventors of the present disclosure found that in an inkjet printer that uses a head cap of the conventional art, a large amount of ink remains on the ink ejection surface after the maintenance. If a large amount of ink remains, the ink may be solidified at the ejection port for ejecting the ink and clogging may occur. Furthermore, when collectively wiping a plurality of ejection surfaces that eject different inks after the maintenance, another ink may affect the ejection port of one ink by the wiping (e.g., the other ink may enter the ejection port of the one ink by the wiping), and color mixing may occur. 
     The present disclosure provides an inkjet printer in which the amount of ink remaining on the ejection surface after maintenance is small. 
     An inkjet printer according to a first aspect of the present disclosure includes an inkjet head including a first protrusion that protrudes downward, the first protrusion having a lower surface provided with a first ejection port for ejecting a first ink as a first ejection surface; and a head cap mounted to the inkjet head when ejecting the first ink from the first ejection port to perform a maintenance on the inkjet head; where the head cap includes a first bottom portion, and a first side wall extending from the first bottom portion toward a side of the inkjet head; the first bottom portion and the first side wall form a first recess that covers the first ejection port when the head cap is mounted to the inkjet head; and the first side wall has a shape in which at least a part of an upper end portion of the first side wall abuts against a region at a periphery of the first ejection surface and does not abut against the first ejection surface when the head cap is mounted to the inkjet head. 
     The inventors of the present application have found that the reason why the amount of ink remaining on the ejection surface after maintenance is large is because the upper end of the head cap abuts against the ejection surface (see e.g., cap member in Japanese Unexamined Patent Publication No. 2018-69713). Therefore, in the disclosure of the present application, the first side wall is shaped so that at least a part of an upper end portion thereof abuts against a region at a periphery of the first ejection surface and does not abut against the first ejection surface when the head cap is mounted to the inkjet head. The amount of ink remaining on the ejection surface after maintenance can be reduced by adopting such a configuration. 
     The first protrusion may include a side surface having an inclined surface, and the upper end portion of the first side wall may include an abutment portion that abuts against the inclined surface. 
     With such a configuration, the head cap is suitably mounted to the inkjet head. 
     The first protrusion may include a side surface having an inclined surface; and the upper end portion of the first side wall may include an abutment portion that abuts against the inclined surface and a periphery of the side surface of the inkjet head. 
     With such a configuration, the head cap is suitably mounted to the inkjet head. 
     The maintenance may be a maintenance by purge. 
     The inventors of the present application have found that the amount of ink remaining on the ejection surface after maintenance is large particularly when performing purge as maintenance. Therefore, the amount of ink remaining on the ejection surface after maintenance can be effectively reduced by adopting the configuration described above. 
     The first ejection surface may be a surface from which the first ink is wiped by wiping. 
     According to the above configuration, the ink remaining on the ejection surface after maintenance can be wiped off. 
     The inkjet head may further include a second protrusion that protrudes downward, the second protrusion having a lower surface provided with a second ejection port for ejecting a second ink as a second ejection surface; when the head cap is mounted to the inkjet head, the first ink and the second ink may be ejected from the first ejection port and the second ejection port, respectively; the head cap may include a second bottom portion, and a second side wall extending from the second bottom portion toward the side of the inkjet head; the second bottom portion and the second side wall may form a second recess that covers the second ejection port when the head cap is mounted to the inkjet head; the inkjet printer may further include a wiping member that collectively wipes the first ejection surface and the second ejection surface after the maintenance; and the second side wall may have a shape in which at least a part of an upper end portion of the second side wall abuts against a region at a periphery of the second ejection surface and does not abut against the second ejection surface when the head cap is mounted to the inkjet head. 
     Mixing of color can be prevented by adopting the configuration described above. 
     According to the present disclosure, an inkjet printer in which the amount of ink remaining on the ejection surface after maintenance is small can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic overall view of an inkjet printer according to one embodiment of the present disclosure. 
         FIGS. 2A and 2B  are configuration views of a first head unit and a second head unit. 
         FIG. 3  is a configuration view of an ink supply mechanism and the like. 
         FIG. 4A  is a cross-sectional view of the first inkjet head take along a short side direction. 
         FIG. 4B  is a cross-sectional view of the first inkjet head taken along a longitudinal direction. 
         FIG. 5  is a configuration view of a maintenance mechanism. 
         FIG. 6A  is a plan view of a head cap. 
         FIG. 6B  is a cross-sectional view of the head cap taken along a short side direction. 
         FIG. 6C  is a cross-sectional view of the head cap taken along a longitudinal direction. 
         FIG. 7A  is a cross-sectional view of that in which the head cap is mounted to the first inkjet head is taken along a short side direction. 
         FIG. 7B  is a cross-sectional view of that in which the head cap is mounted to the first inkjet head is taken along a longitudinal direction. 
         FIG. 8  is a cross-sectional view of that in which the head cap is mounted to the first inkjet head is taken along a short side direction showing a state after purge. 
         FIGS. 9A and 9B  are views showing a state of wiping. 
         FIGS. 10A to 10C  are explanatory views of a conventional head cap. 
         FIGS. 11A to 11C  are views for explaining the effects of the embodiment. 
         FIG. 12  is a cross-sectional view of than in which a head cap according to a modification is mounted to the first inkjet head is taken along a short side direction. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an inkjet printer  10  according to one embodiment of the present disclosure will be described with reference to the attached drawings. 
     (Schematic Configuration of Inkjet Printer  10 ) 
     As shown in  FIG. 1 , the inkjet printer  10  includes a printer main body  11 , a conveying apparatus  12 , and a frame  13 . The inkjet printer  10  is configured to print an image on a medium (here, paper) M through an inkjet method. 
     The printer main body  11  is a portion that prints an image, and is supported by the frame  13  together with the conveying apparatus  12 . The conveying apparatus  12  transports the medium M from the back toward the front along a sub scanning direction (front-back direction) by, for example, a roller. The printer main body  11  includes a first head unit  100  and a second head unit  200  configured to eject the ink to the medium M through the inkjet method. The first head unit  100  and the second head unit  200  are mounted on a carriage (not shown) movably provided in a main scanning direction, and move along the main scanning direction by the movement of the carriage. The printer main body  11  also includes a controller  11 A that controls the operation of the inkjet printer  10 . Although the details will be described later, the printer main body  11  has a maintenance mechanism  500  (see  FIG. 5  etc., not shown in  FIG. 1 ) for performing maintenance (cleaning) on the first head unit  100  and the second head unit  200 . 
     In the inkjet printer  10 , a process in which the first head unit  100  and the second head unit  200  eject ink while moving along the main scanning direction, and a process in which the conveying apparatus  12  moves the medium M along the sub scanning direction are repeatedly carried out. These processes are performed under the control of the controller  11 A. An image is formed (printed) on the medium M by the ejected ink by repeatedly carrying out such processes. 
     (First Head Unit  100  and Second Head Unit  200 ) 
     As shown in  FIG. 2A , the first head unit  100  includes a 1-1 sub tank  110 , a 1-2 sub tank  120 , and a first inkjet head  130 . The 1-1 sub tank  110  and the 1-2 sub tank  120  are disposed on the first inkjet head  130 . 
     The 1-1 sub tank  110  stores ink of Y (yellow) (hereinafter, also referred to as yellow ink). The 1-2 sub tank  120  stores ink of C (cyan) (hereinafter also referred to as cyan ink). The first inkjet head  130  individually ejects the yellow ink and the cyan ink supplied from the 1-1 sub tank  110  and the 1-2 sub tank  120 . The first inkjet head  130  ejects ink in the form of droplets through a piezoelectric method or a thermal method. 
     As shown in  FIG. 2B , the second head unit  200  includes a 2-1 sub tank  210 , a 2-2 sub tank  220 , and a second inkjet head  230 . The 2-1 sub tank  210  and the 2-2 sub tank  220  are mounted on the second inkjet head  230 . 
     The 2-1 sub tank  210  stores ink of M (magenta) (hereinafter also referred to as magenta ink). The 2-2 sub tank  220  stores ink of K (key plate, here, black) (hereinafter also referred to as black ink). The second inkjet head  230  individually ejects the magenta ink and the black ink supplied from the 2-1 sub tank  210  and the 2-2 sub tank  220 . The second inkjet head  230  ejects ink in the form of droplets through a piezoelectric method or a thermal method. 
     (Ink Supply Mechanism  300 ) 
     The printer main body  11  also includes an ink supply mechanism  300  that supplies ink to the 1-1 sub tank  110 , the 1-2 sub tank  120 , the 2-1 sub tank  210 , and the 2-2 sub tank  220 . 
     As shown in  FIG. 3 , the ink supply mechanism  300  includes bottle tanks  311  to  314  and pumps  321  to  324 . 
     The bottle tank  311  is connected to a bottle for yellow ink (not shown, and stores the yellow ink supplied from the bottle. Similarly, the bottle tank  312  is connected to a bottle for cyan ink (not shown) and stores the cyan ink supplied from the bottle. The bottle tank  313  is connected to a bottle for magenta ink (not shown) and stores the magenta ink supplied from the bottle. The bottle tank  314  is connected to a bottle for black ink (not shown) and stores the black ink supplied from the bottle. 
     Each of the bottle tanks  311  to  314  is connected to each of the four sub tanks (1-1 sub tank  110 , 1-2 sub tank  120 , 2-1 sub tank  210 , and 2-2 sub tank  220 ). Each ink stored in the bottle tanks  311  to  314  is supplied to each of the four sub tanks. The supply/non-supply of ink is controlled by the pumps  321 - 324 . 
     Each of the four sub tanks is provided with a liquid level sensor (not shown) that detects the liquid level of the ink. The controller  11 A individually controls each of the pumps  321  to  324  based on the signal from the liquid level sensor so that each of the four sub tanks is filled with ink of greater than or equal to a predetermined amount. For example, when detecting that the liquid level of the ink stored in the 1-1 sub tank  110  is lower than a predetermined position by the liquid level sensor, the controller  11 A drives the pump  321  and performs a control to supply the yellow ink from the bottle tank  311  to the 1-1 sub tank  110 . 
     The printer main body  11  also includes a pneumatic circuit  400  of  FIG. 3 . The pneumatic circuit  400  is configured to include a pneumatic pump, an air chamber, a slot valve and the like, and adjusts the air pressure in the four sub tanks (air pressure of the gas above the ink liquid level) under the control of the controller  11 A. The pneumatic circuit  400  usually supplies a negative pressure, and supplies a positive pressure at the time of maintenance (purge herein) to be described later. The pneumatic circuit  400  may commonly supply negative pressure or positive pressure to each of the four sub tanks, or may supply the pressure individually and independently. 
     Since the ink is always stored in the four sub tanks, the ink supply path from the sub tank to the ink ejection port of the first inkjet head  130  or the second inkjet head  230  is filled with ink. When positive pressure is supplied to the sub tank, the ink in the sub tank is pushed, and the ink is ejected (purge) from the ejection port of the first inkjet head  130  or the second inkjet head  230 . For example, when the positive pressure is supplied to the 1-1 sub tank  110 , the yellow ink is ejected from the ejection port  131 A ( FIG. 4 ) of the yellow ink in the first inkjet head  130 . 
     (Ejector of First Inkjet Head  130  and Second Inkjet Head  230 ) 
     The lower part of the first inkjet head  130  is an ejector that ejects yellow ink and cyan ink. The ejector of the first inkjet head  130  includes, in addition to a plurality of ejection nozzles  131  and  132 , a lower surface  133  facing downward, a first protrusion  134  protruding from the lower surface  133 , and a second protrusion  135  protruding from the lower surface  133 . 
     The plurality of ejection nozzles  131  are provided to pass through the inside of the first protrusion  134 . The plurality of ejection nozzles  131  are arranged in the sub scanning direction, and can each eject the yellow ink independently. The plurality of ejection nozzles  132  are provided to pass through the inside of the second protrusion  135 . The plurality of ejection nozzles  132  are arranged in the sub scanning direction, and can each eject the cyan ink independently. 
     The lower surface  133  forms the lower surface of the first inkjet head  130 , and is also a region at the periphery of the first protrusion  134  and the second protrusion  135 . 
     The first protrusion  134  and the second protrusion  135  are long in the sub scanning direction, and are formed to a quadrangular pyramid shape in which a short-side cross-section taken along the main scanning direction is a trapezoidal shape. 
     The first protrusion  134  has an ejection surface  134 A (lowermost surface, corresponding to upper surface of quadrangular pyramid) which is a lower surface facing downward. The ejection surface  134 A is provided with an opening on the lower side of the ejection nozzle  131 , that is, an ejection port  131 A for yellow ink. Furthermore, the first protrusion  134  includes an inclined surface  134 B (corresponding to side surface of quadrangular pyramid) at the periphery of the ejection surface  134 A. The inclined surface  134 B is a surface in which an angle formed with the ejection surface  134 A is an obtuse angle. The inclined surface  134 B is located between the ejection surface  134 A and the lower surface  133 . The inclined surface  134 B includes a first inclined surface  134 BA extending along the sub scanning direction (longitudinal direction of first protrusion  134 ), and a second inclined surface  134 BB extending along the main scanning direction (short side direction of first protrusion  134 ). 
     The second protrusion  135  has a shape similar to the first protrusion  134 . The second protrusion  135  includes an ejection surface  135 A provided with an opening on the lower side of the ejection nozzle  132 , that is, an ejection port  132 A for cyan ink. Furthermore, the second protrusion  135  includes an inclined surface  135 B. The inclined surface  135 B includes a first inclined surface  135 BA extending along the sub scanning direction and a second inclined surface (not shown) extending along the main scanning direction. 
     (Maintenance Mechanism  500 ) 
     The maintenance mechanism  500  in the printer main body  11  is a mechanism that performs maintenance to prevent clogging of the ejection nozzles of the first inkjet head  130  and the second inkjet head  230 . The first head unit  100  and the second head unit  200  are subjected to maintenance at an appropriate timing when located at the standby position. 
     The maintenance mechanism  500  includes a head cap  510 , a first drive mechanism  520 , a suction device  530 , a wiping blade  540 , and a second drive mechanism  550 . The maintenance mechanism  500  is prepared for the first inkjet head  130  and for the second inkjet head  230 , but as each maintenance mechanism  500  has the same structure, only the maintenance mechanism  500  for the first inkjet head  130  will be described herein. 
     The head cap  510  is mounted (abutted herein) to the first inkjet head  130  at the time of maintenance, and covers the ejection surface  134 A of the first protrusion  134  and the ejection surface  135 A of the second protrusion  135  and receives the ink ejected therefrom by purging. The head cap  510  includes a first recess  511  and a second recess  512  that accommodates ink, respectively. The first recess  511  and the second recess  512  are formed to a shape corresponding to the first protrusion  134  and the second protrusion  135 , and are long in the sub scanning direction. When the head cap  510  is mounted to the first inkjet head  130 , the first recess  511  accommodates and covers the first protrusion  134 , the ejection surface  134 A, and the ejection port  131 A. The second recess  512  accommodates and covers the second protrusion  135 , the ejection surface  135 A, and the ejection port  132 A. 
     The head cap  510  includes a bottom portion  513  and a side wall  514  extending upwardly from the bottom portion  513 . The side wall  514  has a shape combining two squares when viewed from above, and the first recess  511  and the second recess  512  are defined by the bottom portion  513  and the side wall  514 . A portion that defines the first recess  511  in the bottom portion  513  is referred to as a first bottom portion  513 A, and a portion that defines the second recess  512  is referred to as a second bottom portion  513 B. A portion (one square portion) that defines the first recess  511  in the side wall  514  is referred to as a first side wall  514 A, and a portion (one square portion) that defines the second recess  512  is referred to as a second side wall  514 B. 
     The first bottom portion  513 A has a through hole  513 C at the middle. The second bottom portion  513 B has a through hole  513 D at the middle. The through hole  513 C and the through hole  513 D are for discharging the ink stored in the first recess  511  and the second recess  512  in the purge to be described later. A plurality of through holes  513 C and a plurality of through holes  513 D may be provided. 
     The upper surface of the first side wall  514 A has an inclined surface  514 C. The inclined surface  514 C includes a first inclined surface  514 CA extending in the sub scanning direction and a second inclined surface  513 CB extending in the main scanning direction. The first side wall  514 A is shaped so as not to abut against the ejection surface  134 A of the first protrusion  134 . 
     The upper surface of the second side wall  514 B has an inclined surface  514 D. The inclined surface  514 D includes a first inclined surface  514 DA extending in the sub scanning direction and a second inclined surface  513 DB extending in the main scanning direction. The second side wall  514 B is shaped so as not to abut against the ejection surface  135 A of the second protrusion  135 . 
     In the head cap  510 , an upper end portion of the side wall  514 , that is, a portion that abuts against the first protrusion  134  and the second protrusion  135  is formed of an elastic material such as rubber, synthetic resin or the like so as to have elasticity, or may be formed by coating a metal, and the like with an elastic material. 
     The first drive mechanism  520  moves the head cap  510  up and down under the control of the controller  11 A. The first drive mechanism  520  is configured to include a ball screw, a rack and pinion, and the like. The first drive mechanism  520  locates the head cap  510  at the lower position at the time of normal operation (time of non-maintenance), and moves the head cap  510  upward and mounts (abuts herein) it to the first inkjet head  130  at the time of maintenance. 
     The suction device  530  includes one for the first recess  511  (hereinafter also referred to as a first suction device) and one for the second recess  512  (hereinafter also referred to as a second suction device), but as both suction devices have the same structure, the first suction device will be described here. 
     As shown in  FIG. 6 , the suction device  530  (first suction device) includes an ink flow path  531 , a valve (electromagnetic valve etc.)  532 , a pump  533 , and a waste liquid tank  534 . The suction device  530  (first suction device) suctions yellow ink (details will be described later) accumulated in the first recess  511  at the time of purge. 
     The ink flow path  531  is connected to the through hole  513 C provided in the first bottom portion  513 A. The ink flow path  531  flows the yellow ink (described in detail later) accumulated in the first recess  511  of the head cap  510  into the waste liquid tank  534 . The valve  532  and the pump  533  are provided in the middle of the ink flow path  531  and control the flow of the yellow ink under the control of the controller  11 A (details will be described later). 
     The wiping blade  540  is a plate-shaped elastic material, and wipes off the ink attached to the ejection surfaces  134 A and  135 A (details will be described later) by moving while making contact with the ejection surfaces  134 A and  135 A. 
     The second drive mechanism  550  drives the wiping blade  540  under the control of the controller  11 A. The second drive mechanism  550  is configured to include a linkage mechanism, a ball screw, a pinion and rack, or the like. 
     (Maintenance) 
     Although the maintenance is performed with respect to the first inkjet head  130  and the second inkjet head  230 , as both operations are the same, the maintenance of the first inkjet head  130  will be described below. 
     (Mounting of Head Cap  510 ) 
     At the start of maintenance, the controller  11 A moves the head cap  510  upward by the first drive mechanism  520 , presses and abuts (mounts) the head cap  510  against the first inkjet head  130 . The state of this abutment is shown in  FIG. 7 . The inclined surface  134 B of the first protrusion  134  of the first inkjet head  130  and the inclined surface  514 C of the first side wall  514 A have the same inclination angle or the like, and the inclined surface  134 B and the inclined surface  514 C are brought together in an abutted state. Specifically, the first inclined surface  134 BA and the first inclined surface  514 CA are brought together and abutted against each other. The second inclined surface  134 BB and the second inclined surface  514 CB are brought together and abutted against each other. Furthermore, the inclined surface  135 B of the second protrusion  135  of the first inkjet head  130  and the inclined surface  514 D of the second side wall  514 B have the same inclination angle, or the like and the inclined surface  135 B and the inclined surface  514 D are brought together in an abutted state. Specifically, the first inclined surface  135 BA and the first inclined surface  514 DA are brought together and abutted against each other. The second inclined surface  135 BB and the second inclined surface  514 DB are brought together and abutted against each other. 
     In the present embodiment, the inclined surfaces  134 B and  135 B of the first protrusion  134  and the second protrusion  135  of the first inkjet head  130  abut against the inclined surfaces  514 C and  514 D of the side walls  514  of the head cap  510 , but other portions of the first inkjet head  130  are not abutted against the head cap  510 . Specifically, the head cap  510  is not abutted against the lower surface  133  of the first inkjet head  130 , and is also not abutted against the ejection surfaces  134 A and  135 A of the first protrusion  134  and the second protrusion  135 . In particular, the side walls  514  are formed to a shape so as not to overlap the ejection surfaces  134 A and  135 A when viewed in the vertical direction, whereby the head cap  510  does not abut against the ejection surfaces  134 A and  135 A. 
     The abutment between the inclined surfaces facilitates positioning of the head cap  510  to the first inkjet head  130  at the time of abutment. 
     (Maintenance by Purge) 
     After the head cap  510  is mounted, the controller  11 A performs a purge. Specifically, the controller  11 A controls the pneumatic circuit  400  and supplies positive pressure to the 1-1 sub tank  110  and the 1-2 sub tank  120  for a predetermined time. As a result, the yellow ink is ejected from the plurality of ejection nozzles  131  (ejection ports  131 A) of the first inkjet head  130 . At this time, the controller  11 A has the valve  532  of the suction device  530  closed. Therefore, the first recess  511  of the head cap  510  is filled with the yellow ink as shown in  FIG. 8A . Similarly, the cyan ink is ejected from the plurality of ejection nozzles  132  (ejection ports  132 A) of the first inkjet head  130 , and the second recess  512  of the head cap  510  is filled with the cyan ink as shown in  FIG. 8 . 
     (Ink Suction) 
     Thereafter, the controller  11 A controls and opens the valve  532  and controls and operates the pump  533 . Thus, the suction device  530  suctions the yellow ink in the first recess  511  and discharges it to the waste liquid tank  534 . Such suction is also performed on the cyan ink in the second recess  512 . Each ink in the first recess  511  and the second recess  512  may not be completely removed, and ink may attach and remain on ejection surfaces  134 A and  135 A. 
     (Wiping) 
     Thereafter, the controller  11 A controls the second drive mechanism  550  to move the wiping blade  540  in the sub scanning direction while simultaneously bringing the wiping blade  540  into contact with the ejection surfaces  134 A and  135 A (see  FIGS. 9A and 9B ; wiping). Thus, the ink attached to the ejection surfaces  134 A and  135 A (see residual ink L in  FIG. 9B ) can be wiped from both ejection surfaces  134 A and  135 A all at once. 
     (Effects of the Present Embodiment) 
     As shown in  FIGS. 10A to 10C , when the conventional head cap  1510  is mounted to the first inkjet head  130 , a part of the upper end thereof abuts against the ejection surface  134 A of the first protrusion  134 . In this case, even if the ink is suctioned, the ink L 2  remains at the corner of the abutment portion between the head cap  1510  and the ejection surface  134 A ( FIG. 10A ). In such a case, the ink L 2  enters the gap formed when the head cap  1510  is separated from the first inkjet head  130  ( FIG. 10B ), and the ink L 2  remains on the ejection surface  134 A even when the head cap  1510  is completely separated from the first inkjet head  130 . Even in a state in which the head cap  1510  is mounted to the first inkjet head  130 , the ink L 2  remains similar to the above if there is a gap between the head cap  1510  and the ejection surface  134 A. In this case, the ink L 2  may be moved and dried at the ejection port  131 A by the wiping of the wiping blade  540 , and the ejection port  131 A may get clogged. Furthermore, since the wiping by the wiping blade  540  is collectively performed on both the ejection surface  134 A and the ejection surface  135 A, the ink L 2  (yellow ink) may move to the ejection port  132 A of the cyan ink and the color mixture (mixing of color of ink ejected from ejection port  132 A) may occur. The ejection surface  134 A is normally subjected to water-repellent treatment, but the water-repellency degrades due to the aging degradation. With such a degradation, the amount of ink L 2  increases, and the clogging or color mixing appears notably. 
     In this embodiment, when the head cap  510  is mounted to the first inkjet head  130 , the upper ends of the side walls  514  of the head cap  510  do not abut against the ejection surfaces  134 A and  135 A. In such a case, similar to the case of  FIG. 10C , even if the ink L 2  remains at the corner ( FIG. 11A ), the ink L 2  can be guided to the gap formed when the head cap  510  is separated from the first inkjet head  130  ( FIG. 11B ). In such a case, even if the head cap  510  is completely separated from the first inkjet head  130 , the ink L 2  remains on the first inclined surface  134 BA but does not remain on the ejection surface  134 A ( FIG. 11C ). Thus, the amount of ink remaining on the ejection surface  134 A is reduced, and the clogging and color mixing that occur in the subsequent wiping by the wiping blade  540  are also prevented. In particular, even if the water repellency is degraded, the clogging or color mixing can be effectively prevented. 
     (Modifications) 
     The present disclosure is not limited to the embodiment described above. The embodiment described above may be modified in various manners. A known method can be adopted for the maintenance such as the purge. 
     (First Modification) 
     The maintenance may be, for example, flushing (ejection of ink) or suction of ink in the ejection nozzle. Even in these cases, it is assumed that remaining of ink L 2  as shown in  FIGS. 10A to 10C  and  FIGS. 11A to 11C  (in particular, in the case where the ink is scattered) may occur, and hence the present disclosure can also be applied to flushing and the suction described above. However, as the remaining of ink L 2  significantly appears at the time of purge, the present disclosure is particularly effective in an inkjet printer that performs purge. 
     (Second Modification) 
     In the description made above, when the head cap  510  is mounted to the first inkjet head  130 , not all the upper ends of the side walls  514  of the head cap  510  abut against the ejection surfaces  134 A and  135 A, but a part of the upper ends may abut against the ejection surfaces  134 A and  135 A. For example, the side wall  514  may be formed to a shape in which all the portions extending in the longitudinal direction of the side wall  514  do not abut against the ejection surface  134 A or  135 A (e.g., do not overlap when viewed from the vertical direction), and at least a part of the portion extending in the short side direction abuts against the ejection surface  134 A or  135 A. Furthermore, the side wall  514  may be formed to a shape in which all the portions extending in the short side direction of the side wall  514  do not abut against the ejection surface  134 A or  135 A (e.g., do not overlap when viewed from the vertical direction), and at least a part of the portion extending in the longitudinal direction abuts against the ejection surface  134 A or  135 A. Even in such a case, the amount of ink remaining on the ejection surface after maintenance is less than in a mode in which all the upper ends are abutted against the ejection surfaces  134 A and  135 A. 
     (Third Modification) 
     The upper end of the side wall  514  of the head cap  510  may be abutted against the lower surface  133  of the first inkjet head  130 . For example, as shown in  FIG. 12 , the side wall  514  may be formed to a shape in which that the upper surface S of the side wall  514  abuts against the lower surface  133 , in addition to the inclined surface  134 B of the first inkjet head  130  and the like abutting against the inclined surface  514 C and the like. 
     (Fourth Modification) 
     The ejection surface  134 A and the like may have some steps. For example, even if there is a step, if the surface is to be wiped as a whole, such a surface is the ejection surface. Furthermore, the lower surface surrounded by the inclined surface (top of protrusion having inclined surface as side surface) constitutes the ejection surface as a whole even if there is a slight step. 
     (Fifth Modification) 
     The wiping blade  540  (one example of wiping member) may be changed to another wiping member (member that performs wiping (wiping, brushing, etc.)). Moreover, the moving direction may be the main scanning direction.