Patent Publication Number: US-8974036-B2

Title: Ink discharge apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Patent Application No. 2010-138304 filed on Jun. 17, 2010 the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an ink discharge apparatus which performs printing with respect to a recording medium such as paper (paper sheet) with ink droplets of an ink discharged from a plurality of nozzles provided on a nozzle surface of a discharge head. 
     2. Description of the Related Art 
     An ink discharge apparatus has a discharge head provided with a nozzle surface. For example, a plurality of nozzles are disposed on the nozzle surface; and liquid droplets of a deep color ink are jetted from deep color nozzles and liquid droplets of a light color ink are jetted from light color nozzles onto a recording medium such as paper (paper sheet), thereby performing printing on the recording medium. When such a printing operation is repeated, in a case that time interval from the previous printing to the next printing becomes great, etc., clogging of the nozzles occurs in some cases. In order to solve the clogging, a maintenance device is provided on a body of the ink discharge apparatus (apparatus body). 
     The maintenance device is provided with a suction cap and a suction mechanism. The suction cap is brought into contact with the nozzle surface of the discharge head. In a state that the suction cap is brought into contact with the nozzle surface, the suction mechanism is connected to a suction port provided on the suction cap, and the suction mechanism performs suction operation via the suction port, thereby removing ink solid matter, etc. clogged in the nozzles (so-called suction purge process). 
     In the suction purge process, the suction cap into which the ink is discharged is separated away from the nozzle surface so as to suck and remove the ink discharged in the suction cap, and the suction mechanism performs suction operation in a state that the contact state between the suction cap and the nozzle surfaces is released. 
     Conventionally, there has been suggested an ink discharge apparatus having a construction in which the suction cap is inclinable with respect to a carriage. In the ink discharge apparatus, the suction cap is inclined so that a portion, of the suction cap on a side of one end thereof (one end side), is open with respect to the nozzle surface and that the ink adhered to the nozzle surface is collected to the portion on the one end side of the suction cap; and the ink inside the suction cap is sucked. 
     SUMMARY OF THE INVENTION 
     Generally, in ink discharge apparatuses, a position at which the nozzle surface is installed in the discharge head (install position) is varied due to the installation error during the manufacture, etc. In order to tolerate this variation in the install position and to securely obtain the contact of the suction cap to the nozzle surface, a construction is considered in which the suction cap is installed (arranged) in the apparatus body with a predetermined clearance to make the suction cap be freely rockable three-dimensionally. Alternatively, another construction is considered in which the suction cap is provided with a partition wall so that the deep color nozzles and the light color nozzles can be covered with separate spaces, respectively, in a state that the suction cap is brought into contact with the nozzle surface. For example, a cap chamber of the suction cap is partitioned into two areas which are a deep color ink chamber and a light color ink chamber. 
     However, in a case that the suction cap is constructed to be three-dimensionally rockable, there is a fear that the ink might flow out of a cap chamber over the partition wall and inflow (enter) into another ink chamber adjacent to the cap chamber and mix with the ink in the adjacent cap chamber. In this situation, for example, if the deep color ink inflows into the light color ink chamber, the inside of the light color ink chamber is dirtied (stained) by the deep color ink. Such a dirtiness in the light color ink chamber cannot be completely removed by the suction alone. As a result, when the suction purge process is again performed in a state that the inside of the cap chamber (light color ink chamber) is dirtied by the deep color ink, there is a fear that the dirtied suction cap might be brought into contact with the nozzle surface, which in turn causes the deep color ink to adhere to the light color nozzles, thereby dirtying the light color nozzles. 
     An object of the preset teaching is to provide an ink discharge apparatus capable of suppressing the adhesion of the deep color ink to the light color nozzles and preventing the light color nozzles from being dirties by the deep color ink in a structure in which the cap member (suction cap member) is configured to be rockable for the purpose of tolerating the variation in the install position of the nozzle surface. 
     According to a first aspect of the present teaching, there is provided an ink discharge apparatus which discharges a first ink and a second ink having a color deeper than a color of the first ink, the ink discharge apparatus including: 
     a discharge head provided with a nozzle surface having a first nozzle which is formed in the nozzle surface and via which a liquid droplet of the first ink is discharged and a second nozzle which is formed in the nozzle surface and via which a liquid droplet of the second ink is discharged; and 
     a maintenance device which performs maintenance of the discharge head, the maintenance device including:
         a suction cap which is brought into contact with the nozzle surface to cover the first and second nozzles, and which has a partition wall and a suction port formed therein, the partition wall partitioning a space, defined between the suction cap and the nozzle surface in a state that the suction cap is brought into contact with the nozzle surface, into a first ink chamber facing the first nozzle and a second ink chamber facing the second nozzle,   a suction mechanism which is connected to the suction port of the suction cap, and   an urging mechanism which urges a corner portion of the suction cap in a third direction orthogonal to the nozzle surface; and       

     an apparatus body in which the maintenance device is arranged; 
     wherein the corner portion is located at an end, of the suction cap, on a side of the first ink chamber in a first direction, that is from the first nozzle toward the second nozzle and is parallel to the nozzle surface, and is located at an end in one side in a second direction, that is orthogonal to the first direction and is parallel to the nozzle surface; and 
     the suction cap is arranged with respect to the apparatus body with a predetermined clearance so that the suction cap is rockable in each of the first direction, the second direction and the third direction. 
     In general, the install position of the nozzle surface in the discharge head is varied due to the installation error during the manufacture, etc. In order to ensure that the suction cap is brought into contact with the nozzle surface while tolerating the variation in the install position, the suction cap is arranged, with the predetermined clearance, in the apparatus body to be rockable three-dimensionally in each of the first direction, the second direction orthogonal to the first direction and parallel to the nozzle surface and the orthogonal direction (third direction) orthogonal to the nozzle surface. Further, the suction cap is provided with the partition wall and is capable of covering the second nozzle (deep color nozzle) and the first nozzle (light color nozzle) with separate spaces, respectively, in a state that the suction cap is brought into contact with the nozzle surface. 
     However, since the suction cap is configured to be rockable in the three directions as described above, there is a fear that the ink might flow or move over or across the partition wall. In such a situation, if, for example, the second ink (deep color ink) inflows or enters into the side of the first ink chamber (light color ink chamber), the inside of the first ink chamber is dirtied by the second ink having the deep color. Such the dirtiness or stain cannot be completely removed or cleaned by the ink suction alone. As a result, when the purge process is executed again in such a state that the inside of the first ink chamber is dirtied by the second ink, there is a fear that the dirtied suction cap might be brought into contact with the nozzle surface, consequently causing the second ink to adhere to the first nozzle (light color nozzle), thereby dirtying the first nozzle. 
     In view of such a situation, in the ink discharge apparatus of the present teaching, the urging mechanism urges the suction cap in the orthogonal direction at the corner portion, of the suction cap, which is positioned in the suction cap at a portion of the first ink chamber, the portion being located on the opposite side opposite to the second ink chamber in the first direction and is located in the suction cap on the one side in the second direction. By urging the corner portion, of the first ink chamber, located on the opposite side opposite to the second ink chamber, the suction cap is inclined, while the suction cap is being separated away from the nozzle surface, so that a portion, of the suction cap, on the side of the second ink chamber is separated and away from the nozzle surface by a greater distance than another portion, of the suction cap, on the side of the first ink chamber. With this, even if the ink flows or moves over the partition wall, it is possible to make the first ink having the light color inflow (enter) into the second ink chamber, rather than the second ink having the deep color inflowing into the first ink chamber as described above. As a result, even when the first ink flows into and mixes with the second ink, the influence on the tint or color of the second ink is small than in a case that the second ink flows into and mixes with the first ink, thereby making it possible to suppress the influence on the tint or color of the ink to be considerably small. Therefore, it is possible to suppress the adhesion of the second ink to the first nozzle and prevent the first nozzle from being dirtied. 
     According to the present teaching, in the structure in which the cap body (cap member) is configured to be rockable to tolerate the variation in the install position of the nozzle surface, it is possible to suppress the adhesion of the second ink having the deep color to the first nozzle and suppress the dirtiness of the first nozzle due to the second ink. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plane view showing main constitutive parts or elements of a printer. 
         FIG. 2  is a bottom view showing construction of a carriage on the side of bottom surface thereof. 
         FIG. 3  is a plane view showing main constitutive parts or elements of a maintenance device. 
         FIG. 4  is a perspective view showing the main constitutive parts or elements of the maintenance device. 
         FIG. 5  is a schematic view showing expanded shape of a groove portion. 
         FIG. 6  is a side view schematically showing a construction of the maintenance device from the side portions or units thereof. 
         FIGS. 7A ,  7 B and  7 C are side views each schematically showing an operation for moving a position of a suction cap. 
         FIGS. 8A ,  8 B and  8 C are side views each schematically showing a change in posture of the suction cap. 
         FIG. 9  is a flow chart showing steps in a purge process. 
         FIG. 10  is a cross-sectional view showing a state that the suction cap is separated away from a nozzle surface. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following, an embodiment of the present teaching will be explained with reference to the drawings. In this embodiment, the present teaching is applied to a printer which performs printing of a desired text (letter) and/or a desired image on a recording paper (recording sheet) by jetting (discharging) an ink from a discharge head onto the recording paper. 
     With reference to  FIG. 1 , an explanation will be given about the schematic construction of a printer  2  as an embodiment of the ink discharge apparatus of the present teaching. 
     The printer  2  has an apparatus body  2 A which is provided with a printing unit  24 . The printing unit  24  includes a discharge head  39  of the ink-jet system and a carriage  38  in which the discharge head  39  is provided on a side of the bottom surface of the carriage  38 . The carriage  38  is supported to be slidable in a scanning direction (left/right direction in  FIG. 1 ) orthogonal to a transporting direction of the recording paper (direction from the upper side to the lower side of  FIG. 1 ). 
     A pair of guide rails  43 ,  44  are arranged with respect to the carriage  38  on a side of the both end portions of the carriage  38  in the transporting direction, respectively. The guide rails  43 ,  44  face (are opposite to) each other with a predetermined distance in the transporting direction of the recording paper therebetween, and extend in the scanning direction. The guide rails  43 ,  44  are disposed inside the casing or housing of the printer  2 , and construct a part of a frame which supports the respective members constructing the printer  2 . The carriage  38  is arranged to straddle the guide rails  43 ,  44  and to be slidable movable in the scanning direction. 
     An edge portion  45 , of the guide rail  44 , located on the upstream in the transporting direction is bent upward substantially at right angle. The carriage  38  supported by the guide rails  43 ,  44  pinches and holds the edge portion  45  with holding members  21 ,  22  (see  FIG. 2 , to be described later on) so that the carriage  38  is slidably movable. With this, the carriage  38  is positioned with respect to the transporting direction of the recording paper, and the carriage  38  is slidably movable in the scanning direction. 
     A belt drive-transmitting mechanism  46  is arranged on the upper surface of the guide rail  44 . The belt drive-transmitting mechanism  46  has a driving pulley  47 , a driven pulley  48  and an endless loop-shaped belt  49 . 
     The driving pulley  47  and the driven pulley  48  are arranged on both ends in the scanning direction, respectively. The endless loop-shaped belt  49  is arranged to be stretched between the driving pulley  47  and the driven pulley  48 . A driving shaft of a carriage motor (not shown) disposed inside the printer  2  is connected to the shaft of the driving pulley  47 . Rotary driving force of the carriage motor is transmitted to the driving pulley  47  to rotate the driving pulley  47 , which in turn makes the belt  49  move in circular motion. 
     The carriage  38  is connected to the belt  49  on a side of the bottom surface thereof. Accordingly, the carriage  38  moves slidably (slides) on the guide rails  43 ,  44 , with the end portion  45  as the reference, based on the circular motion of the belt  49 . In such a manner, the carriage motor moves the carriage  38 . The discharge head  39  is placed on or attached to such a carriage  38 , and the discharge head  39  reciprocates in the scanning direction. 
     A platen  42  is disposed at a position below the discharge head  39  so that the platen  49  faces the discharge head  39 . The platen  42  is arranged across a center portion of a moving range of the carriage  38 , namely across an area in which the recording paper passes. Since the width of the platen  42  is sufficiently greater than the maximum width of a transportable recording paper, the both end portions of the recording paper always pass on the platen  42 . 
     A maintenance device  51  is arranged at a range or region, in the apparatus body  2 A of the printer  2 , in which the recording paper does not pass, namely a range outside the printing region by the discharge head  39 . In  FIG. 1 , the maintenance device  51  is arranged at the right end portion of the platen  42 . In the discharge head  39  of the ink jet system, when a long period of time elapsed as time interval from previous printing to next printing, etc., then clogging of nozzles  40  (see  FIG. 2 ) occurs in some cases. Accordingly, the maintenance device  51  prevents the clogging of nozzles by preventing the ink inside the nozzles  40  in the discharge head  39  from being dried, by sucking and removing air bubbles and/or foreign matter from the nozzles  40 , etc. In the embodiment, when no printing is performed, the carriage  38  is arranged at a position above or over the maintenance device  51 . Namely, the carriage  38  stands by at the position above the maintenance device  51  until next printing instruction is given. The maintenance device  51  will be described in detail later on. Note that the printing operation of the printer  2 , the maintenance process of the maintenance device  51  (for example, a purge process as described later on), etc. are controlled by a controller  120  (see  FIG. 1 ). The controller  120  includes, for example, a CPU, a ROM, a RAM, etc., and controls revolution of the carriage motor which drives the carriage  38 , driving of a cam mechanism  60  (to be described later on) of the maintenance device  51 , driving of a suction mechanism (to be described later on), etc. 
     Next, an explanation will be given about the construction of the carriage  38  on the side of the bottom surface thereof, with reference to  FIG. 2 . 
     As shown in  FIG. 2 , the discharge head  39  is arranged on the bottom surface of the carriage  38 , and a nozzle surface  30  of the discharge head  39  is exposed on the side of the lower surface of the carriage  38 . A plurality of nozzles  40  are formed in the nozzle surface  30 . A plurality of color inks (four color inks in the embodiment) are supplied to the discharge head  39  from ink cartridges, respectively, arranged inside the printer  2 . Four sub-tanks  23   a - 23   d,  storing the four color inks which are to be supplied to the discharge head  39  from the ink cartridges respectively, are mounted or placed inside the carriage  38 . Black, cyan, magenta and yellow inks are stored in the sub-tanks  23   a - 23   d,  respectively. The nozzles  40  include black color nozzles  40   a  jetting liquid droplets of the black color ink supplied from the sub-tank  23   a  and color nozzles  40   b  jetting liquid droplets of the color inks (cyan, magenta and yellow inks) supplied from the sub-tanks  23   b - 23   d.  While the carriage  38  is reciprocating in the scanning direction, minute droplets of the inks are selectively discharged from the nozzles  40  of the discharge head  39 . With this, printing is performed on a recording medium transported on the platen  42 . 
     As described above, the holding members  21 ,  22  which pinch and hold the edge portion  45  of the guide rail  44  are provided on the side of the bottom surface of the carriage  38 . The holding member  21  is a fixed-type pinching/holding member which is fixed with respect to the carriage  38 ; on the other hand, the holding member  22  is configured to be a movable-type pinching/holding member which is movable with respect to the carriage  38 . Generally, in the printer  2 , the install position of the nozzle surface  30  in the discharge head  39  is varied (deviated, fluctuated) in some cases due to any installation error during the manufacture, etc. Due to such variation in the install position, in some cases, the transporting direction of the recording paper and the alignment (arrangement) direction of the nozzles  40  of the discharge head  39  (up/down direction in  FIG. 2 ) are not parallel. Even in such a situation, by adjusting the position of the above-described pinching/holding member  22  of the movable type, it is possible to reciprocate the discharge head  39  in the scanning direction while making the transporting direction of the recording paper and the arrangement direction of the nozzles  40  be parallel to each other. 
     Note that the color ink (color inks) and the black color ink correspond to the first ink (light color ink) and the second ink (deep color ink) and the black color nozzle  40   a  and the color nozzle  40   b  correspond to the second nozzle (deep color nozzle) and the first nozzle (light color nozzle), respectively, of the present teaching. 
     Next, an explanation will be given about the maintenance device  51  with reference to  FIGS. 3 to 5 . 
     The maintenance device  51  includes a suction cap  55 , an exhaust cap  56 , an outer frame section  50  supporting the suction cap  55  and the exhaust cap  56 , a maintenance base  57  to which the outer frame section  50  is attachable or mountable, a changeover valve  63 , and a cam mechanism  60 . 
     When the carriage  38  is moved to a capping position (position indicated by two-dot chain lines in  FIG. 6  which will be described later on) set to be directly above the maintenance device  51 , the suction cap  55  is brought into contact with the nozzle surface  30  of the discharge head  39  so as to cover the plurality of nozzles  40 . As shown in  FIGS. 3 and 4 , the suction cap  51  is provided with an outer periphery portion  58  at the outer periphery portion thereof. Inside the outer periphery portion  58 , a partition wall  52  is provided which partitions an inner space, defined by the nozzle surface  30  and the suction cap  55  in a state that the suction cap  55  is brought into contact with the nozzle surface  30 , into two spaces. Namely, the partition wall  52  partitions (divides) the inner space into a black color ink chamber  55 A which is located on one side in the scanning direction parallel to the nozzle surface  30  (left side in  FIGS. 3 and 4 ) and which faces or is opposite to the black color nozzles  40   a,  and a color ink chamber  55 B which is located on the other side in the scanning direction (right side in  FIGS. 3 and 4 ) and which faces or is opposite to the color nozzles  40   b.  Note that the scanning direction parallel to the nozzle surface corresponds to the first direction of the present teaching. In the following, the scanning direction is appropriately referred to as the “first direction”. 
     Suction ports  53  and  54  are provided on the inside of the outer periphery portion  58  and in the black color ink chamber  55 A and the color ink chamber  55 B, respectively, each at a position on one side in the transporting direction (lower end side in  FIG. 3 ). A pump  110  (see  FIG. 10 ) as the suction mechanism is connected to the suction ports  53  and  54 . Here, the transporting direction means a direction orthogonal to the first direction and parallel to the nozzle surface  30 , and corresponds to the second direction of the present teaching. In the followings, the transporting direction is appropriately referred to as the “second direction”. 
     The outer frame section  50  supporting the suction cap  55  is supported with respect to the maintenance base  57  elastically in the up and down direction via a plurality of coil springs  65  disposed between a lower portion of the outer frame section  50  and the bottom surface of the maintenance base  57  (see  FIGS. 6 and 7  which will be described later on). Since the outer frame section  50  is elastically supported in such a manner, the suction cap  55  is arranged with respect to the maintenance base  57  (in other words, with respect to the apparatus body  2 A) with a predetermined clearance to be rockable in each of the first direction, the second direction and the vertical direction orthogonal to the first and second directions. The vertical direction described above corresponds to the third direction of the present teaching. In the followings, the vertical direction is appropriately referred to as the “third direction”. 
     Note that the present teaching is not limited to the construction in which the outer frame section  50  is elastically supported with respect to the maintenance base  57  via the coil springs  65 . For example, it is allowable that a guide groove is formed in the maintenance base  57  and a projection, etc. which is engageable with the guide groove is formed on the outer frame section  50 , and that the outer frame section  50  is supported with respect to the maintenance base  57  via the projection, etc. engaged with the guide groove. In such a case and when the width of the guide groove is formed to be greater than the width of the projection, the outer frame section  50  is rockable in each of the first to third directions by an amount corresponding to a clearance between the guide groove and the projection. 
     The exhaust cap  56  is brought into contact with an opening surface  71  (see  FIG. 2 ) formed with exhaust ports which are connected to the sub-tanks  23   a - 23   d  communicating with the discharge head  39 . The exhaust cap  56  is used to suck and exhaust air bubbles from an ink flow passage upstream of the nozzles  40 . 
     The suction cap  55  is constructed to be rockably movable as described above. Accordingly, even in a case that the install position of the nozzle surface  30  in the discharge head  39  is varied due to the installation error, etc., as described above, it is possible to ensure that the suction cap is brought into contact with the nozzle surface  30  while tolerating the variation of the install position. 
     Note that as shown in  FIG. 3 , the outer frame section  50  is provided with projections  72  and  73  which project in the first direction at one side surface (first side surface)  50   b  (left side in  FIG. 3 ) and the other side surface (second side surface)  50   c  (right side in  FIG. 3 ) of the maintenance base  57 , respectively. On the other hand, the maintenance base  57  is provided with groove portions  74  which are formed in the maintenance base  57  on the one side and the other side, respectively of the first direction and which guide the projections  72  and  73 , respectively. The groove portions  74  regulate the movement of the outer frame section  50  toward the both sides in the second direction, and which guide the projections  72 ,  73  respectively so that the outer frame section  50  moves in the third direction between a contact position at which the suction cap  55  is brought into contact with the nozzle surface  30  and a separate position at which the suction cap  55  is separated and away from the nozzle surface  30 . As shown in  FIG. 5 , each of the groove portions  74  is constructed so that a width size L 2  at the upper side in the second direction is greater than a width size L 1  at the lower side in the second direction. Namely, the groove portions  74  are each formed to have a reverse tapered shape gradually widening from the separate position toward the contact position in the third direction. 
     Further, as shown in  FIGS. 3 and 4 , the maintenance device  51  has a coil spring  75  which urges the suction cap  55  upward in the third direction in the vicinity of a corner portion C, of the color ink chamber  55 B, the corner portion C being positioned on an opposite side opposite to the black color ink chamber  55 A in the first direction and is positioned on a side of one end (one end side) of the suction cap  55  in the second direction. The coil spring  75  is arranged between the maintenance base  57  and the bottom surface of the outer frame section  50 . The coil spring  75  corresponds to the urging mechanism of the present teaching. 
     The cam mechanism  60  is arranged at a position below or under the outer frame section  50 . The cam mechanism  60  includes a slide cam  11 , a second pinion gear  15 , a third pinion gear  16 , a first rack gear  17  and a second rack gear  18 . The cam mechanism  60  is capable of holding the suction cap  55  at the contact position at which the suction cap  55  is brought into contact with the nozzle surface  30  and at the separate position at which the suction cap  55  is separated away from the nozzle surface  30 . 
     Next, an explanation will be given about an operation for moving the suction cap between the contact position and the separate position by the cam mechanism  60 , with reference to  FIGS. 6 and 7 . 
     In a case that the coil springs  65  which elastically support the outer frame section  50  are allowed to have a natural length, namely in a state that any external force is not applied to the outer frame section  50 , the suction cap  55  is arranged at the separate position at which the suction cap  55  is separated away from the discharge head  39  (see  FIGS. 6 and 7A ). When the outer frame section  50  is pushed upward by the slide cam  11 , the coil springs  65  are stretched and the suction cap  55  moves (is moved) from the separate position to the contact position (see  FIG. 7C ) at which the suction cap  55  is brought into contact with the discharge head  39  and covers the nozzle surface  30 . 
     Actually, when the suction cap  55  is positioned at a position other than the contact position, the suction cap  55  assumes an inclined posture due to the urging force of the above-described coil spring  75 . However, for making the explanation be easy to understand, it is assumed that in  FIGS. 6 and 7  the suction cap  55  moves while assuming a horizontal posture. Change in the posture of the suction cap  55  by the coil spring  75  will be explained later on (see  FIG. 8 ). 
     The changeover valve  63  is attached at a position below or under the maintenance base  57 . The changeover valve  63  has tube joints  64  which are connected to the suction ports  53 ,  54  of the suction cap  55  and the exhaust cap  56 , respectively. An end of a tube (not shown in the drawings) is connected to each of the tube joints  64 , and the other end of the unillustrated tube is connected to the pump. Adjustment is made by using the changeover  63  so that at least one of the suction ports  53 ,  54  is communicated with the pump  110 , or that the pump  110  and the exhaust cap  56  are communicated, in a state that the suction cap  55  is moved (has moved) to the contact position and covers the nozzle surface  30 . At this time, when the pump  110  is driven in a state that at least one of the suction ports  53 ,  54  is communicated with the pump  110 , the ink inside the nozzles  40  is forcibly sucked and exhausted (discharged) by the pump  110 . Such an operation is referred to as suction purge process. 
     As shown in  FIG. 6 , an abutting portion  37  for defining the posture of the suction cap  55  when the suction cap  55  is brought into contact with the nozzle surface  30  is provided on the carriage  38  so that the abutting portion  37  projects from the carriage  38  in the second direction. On the other hand, a recess-shaped abutted portion  59 , against which the abutting portion  37  formed on the carriage  38  abuts, is provided on the outer frame section  50  at an inner circumference surface thereof. 
     The slide cam  11  is supported to be movable in the second direction orthogonal to the scanning direction of the carriage  38 . The slide cam  11  has a guide surface which is abutted against the lower surface (bottom portion)  50   a  of the outer frame section  50 . As shown in  FIG. 6 , the guide surface includes a first guide surface  111  located at a high position in the vertical direction and a second guide surface  112  located at a low position in the vertical direction and an inclined surface  113  connecting the first guide surface  111  and the second guide surface  112 . 
     As shown in  FIG. 7A , in a case that only the second guide surface  112  enters (is displaced) into a gap between the lower surface  50   a  of the outer frame section  50  and the upper surface of the maintenance base  57 , and that the second guide surface  112  and the lower surface  50   a  of the outer frame section  50  are brought into abutment with each other, the suction cap  55  is held (maintained) at the separate position. 
     When the slide cam  11  slidably moves, by driving force transmitted from an unillustrated driving source, toward the one side in the second direction (rightward in  FIG. 7 ); then as shown in  FIG. 7B , the inclined surface  113 , in addition to the second guide surface  112 , also enters into the gap between the lower surface  50   a  of the outer frame section  50  and the upper surface of the maintenance base  57 . With this, the second guide surface  112  is separated and away from the lower surface  50   a  of the outer frame section  50  and the inclined surface  113  is brought into abutment against the lower surface  50   a  of the outer frame section  50 . As a result, the suction cap  55  moves from the separate position toward the contact position in accordance with the height of the inclined surface  113 . 
     When the slide cam  11  slidably moves, by the driving force transmitted from the unillustrated driving source, further toward the one side in the second direction (rightward in  FIG. 7 ), then as shown in  FIG. 7C , the first guide surface  111 , in addition to the second guide surface  112  and the inclined surface  113 , also enters into the gap between the lower surface  50   a  of the outer frame section  50  and the upper surface of the maintenance base  57 . With this, the inclined surface  113  is separated away from the lower surface  50   a  of the outer frame section  50 , and the first guide surface  111  abuts against the lower surface  50   a  of the outer frame section  50 . As a result, the suction cap  55  is held at the contact position. In such a manner, the suction cap  55  moves between the separate position and the contact position by the movement of the slide cam  11 . 
     Next, an explanation will be given about the posture change of the suction cap  55  by the urging force of the coil spring  75 , with reference to  FIG. 8 . Note that the states of the slid cam  11  shown in  FIGS. 8A ,  8 B and  8 C corresponds to those shown in  FIGS. 7A ,  7 B and  7 C, respectively. 
     As shown in  FIG. 8A , in a state that the suction cap  55  is held at the separate position, the outer frame section  50  is urged upward in the third direction by the coil spring  75 . Here, with respect to the second direction, the coil spring  75  is disposed on the outer frame section  50  at the corner portion on the side of the suction ports  53  and  54 . Therefore, the outer frame section  50  and the suction cap  55  are inclined by the urging force of the coil spring  75  so that the portion, of the suction cap  55 , on the side of the suction ports  53 ,  54  is located in the third direction on upper side of another portion of the suction cap  55  on the opposite side opposite to the suction ports  53 ,  54 . Further, with respect to the first direction, the coil spring  75  is disposed in the outer frame section  50  at the corner portion which is located on the opposite side opposite to the black color ink chamber  55 A. Therefore, the outer frame section  50  and the suction cap  55  are inclined by the urging force of the coil spring  75  so that the portion, of the suction cap  55 , on the side of the color ink chamber  55 B is located in the third direction on upper side of another portion of the suction cap  55  located on the side of the black color ink chamber  55 A. 
     When the slide cam  11  slidably moves to the one side in the second direction (rightward in  FIG. 8 ), then as shown in  FIG. 8B , the suction cap  55  moves from the separate position toward the contact position in accordance with the height of the inclined surface  113 . At this time also, the suction cap  55  is inclined by the urging force of the coil spring  75  so that with respect to the second direction, the portion of the suction cap  55  on the side of the suction ports  53 ,  54  is located in the third direction on the upper side of the another portion of the suction cap  55  on the opposite side to the suction ports  53 ,  54 ; and that with respect to the first direction, the portion of the suction cap  55  on the side of the color ink chamber  55 B is located in the third direction on the upper side of the another portion of the suction cap  55  on the side of the black color ink chamber  55 A. Note that in this situation, the inclination angle of the suction cap  55  is smaller than that shown in  FIG. 8A . 
     When the slide cam  11  further slidably moves to the one side in the second direction (rightward in  FIG. 8 ), then as shown in  FIG. 8C , the suction cap  55  is held at the contact position. At this time, the height position to which the outer frame section  50  and the suction cap  55  are pushed upward by the urging force of the coil spring  75  and the height position of the first guide surface  111  of the slide cam  11  become substantially identical. Therefore, the outer frame section  50  and the suction cap  55  are horizontal (level) in either of the first and second directions. Accordingly, it is possible to bring the suction cap  55  into contact with the nozzle surface  30 . 
     The purge process is performed in a state that the outer frame section  50  and the suction cap  55  are substantially horizontal in each of the first and second directions and that the suction cap  55  is brought into contact with the nozzle surface  30 . In the following, steps of the purge process will be explained with reference to a flow chart shown in  FIG. 9 . At first, with the above-described procedure, the suction cap  55  is brought into contact with the nozzle surface  30  (S 1 ). In a state that the suction cap  55  is brought into contact with the nozzle surface  30 , the switchover valve  63  is switched to communicate the suction port  53  with the pump  110  (S 2 ). The pump  110  is driven in this state to negatively pressurize a space surrounded by the black color ink chamber  55 A of the suction cap  55  and the nozzle surface  30 , thereby forcibly sucking the black color ink inside the nozzles  40  (S 3 : suction purge step). Next, the suction cap  55  is separated away from the nozzle  30  by moving the slide cam  11  in a procedure reverse to that performed for bringing the suction cap  55  into contact with the nozzle surface  30  (S 4 ). The pump  110  is driven in a state that the suction cap  55  is separated away from the nozzle surface  30 , thereby sucking the black color ink stored or accumulated inside the black color ink chamber  55 A of the suction cap  55  (S 5 : empty suction step). Afterwards, the steps of Si to S 5  are performed again to perform suction of the color ink. Specifically, the suction cap  55  is brought into contact with the nozzle surface  30  (S 6 ). In a state that the suction cap  55  is brought into contact with the nozzle surface  30 , the switchover valve  63  is switched to communicate the suction port  54  with the pump  110  (S 7 ). The pump  110  is driven in this state to negatively pressurize a space surrounded by the color ink chamber  55 B of the suction cap  55  and the nozzle surface  30 , thereby forcibly sucking the color ink inside the nozzles  40  (S 8 : suction purge step). Next, the suction cap  55  is separated away from the nozzle surface  30  by moving the slide cam  11  in the procedure reverse to that performed for bringing the suction cap  55  into contact with the nozzle surface  30  (S 9 ). The pump  110  is driven in a state that the suction cap  55  is separated away from the nozzle surface  30 , thereby sucking the color ink stored or accumulated inside the color ink chamber  55 B of the suction cap  55  (S 10 : empty suction step). 
     In the above explanation, the purge process is performed first for the black color ink and then the purge process is performed for the color ink. However, the present teaching is not limited to such an aspect; it is allowable to perform the purge process for the color ink before the purge process for the black color ink. Further, in the above explanation, the suction purge is performed to forcibly suck the ink inside the nozzles by the pump  110  in a state that the suction cap  55  is brought into contact with the nozzle surface  30 . However, the present teaching is not limited to such an aspect; it is allowable, for example, to drive the discharge head  39  in the state that the suction cap  55  is brought into contact with the nozzle surface  30  and to discharge the black color ink or the color ink toward the suction cap  55 , thereby forcibly discharge the ink inside the nozzles. 
     Here, when the suction cap  55  is moved to be separated away from the nozzle surface  30  after the purge process is completed, the state shown in  FIG. 8C  is changed to the state shown in  FIG. 8B , and then the state shown in  FIG. 8A  is provided. Namely, when the suction cap  55  is being separated away from the nozzle surface  30 , the suction cap  55  is inclined so that the portion of the suction cap  55  on the side of the black color ink chamber  55 A is separated further from the nozzle surface  30  in the third direction by a distance greater than the another portion of the suction cap  55  on the side of the color ink chamber  55 B, and is inclined so that the portion of the suction cap  55  on the side of the other end (opposite side to the suction ports  53 ,  54 ) is separated further from the nozzle surface  30  in the third direction by a distance greater than the another portion of the suction cap  55  on the one end side (side of the suction ports  53 ,  54 ). 
     The effects obtained by making the suction cap  55  assume such a posture will be explained with reference to  FIG. 10 . 
     As described above, in the embodiment, the suction cap  55  is configured to be rockable freely in three directions that are the first, second and third directions. Accordingly, there is a fear that the ink(s) might flow beyond the partition wall  52  depending on a rocking direction of the suction cap  55 . At this time, for example, if the black color ink flows and enters from the side of the black color ink chamber  55 A to the side of the color ink chamber  55 B, the color ink chamber  55 B is dirtied or stained by the black color ink. Such dirtiness inside the ink chamber in the suction cap cannot be completely removed only by sucking the ink from the cap chamber. As a result, when the suction purge process is performed again in a state that the color ink chamber is dirtied by the black color ink, there is a fear that the dirtied suction cap  55  might be brought into contact with the nozzle surface  30 , which in turn might make the black color ink adhere to the color nozzles  40   b,  thereby dirtying the color ink nozzles  40   b.    
     In the embodiment, as described above, the coil spring  75  urges the suction cap  55  in the third direction (up and down direction in  FIG. 10 ) in the vicinity of the corner portion C located in the color ink chamber  55 B at the side opposite to the black color ink chamber  55 A in the first direction (left and right direction in  FIG. 10 ) and is located at the one end side of the suction cap  55  in the second direction (direction perpendicular to the sheet surface of  FIG. 10 ). With this, as shown in  FIG. 10 , the suction cap  55  is inclined so that the portion thereof on side of the black color ink chamber  55 A is separated, in the third direction, further from the nozzle surface  30  by a distance greater than another portion of the suction cap  55  on the side of the color ink chamber  55 B when the suction cap  55  is being moved separate and away from the nozzle surface  30 . Accordingly, even when the ink flows beyond the partition wall  52 , it is possible to make the color ink inflow to the side of the black color ink chamber  55 A, rather than the black ink inflows to the side of the color ink chamber  55 B. As a result, even if the color ink inflows into and mixes with the black color ink, the influence to the hue or color of the black color ink is small, and it is possible to make the influence on the color of the ink be greatly smaller than in a case that the black color ink enters into and mixes with the color ink. Therefore, it is possible to suppress the dirtying of the color nozzles  40  due to the black color ink. 
     Wit the embodiment, in particular, the following effect can also be obtained. Namely, after the suction purge step is completed for the black color ink or the color ink, the suction cap  55  is moved to be separate and away from the nozzle surface  30  in the third direction. At this time, immediately after the completion of the suction purge step, the ink is stored (accumulated) in the inner space of the suction cap  55 . In a case that the suction cap  55  is being separated away from the nozzle surface  30  while being inclined, the ink flows, owning to the action of surface tension, from a portion, of the suction cap  55 , separated from the nozzle surface  30  by a greater separating distance in the third direction to another portion, of the suction cap  55 , separated from the nozzle surface  30  by a smaller separating distance. In this embodiment, the coil spring  75  urges the portion, of the suction cap  55 , on the one end side in the second direction as described above. Therefore, with respect to the third direction, the separating distance at the portion of the suction cap  55  on the one end side is smaller than the separating distance at the another portion of the suction cap  55  on the other end side. Consequently, the ink flows from the other end side to the one end side in the suction cap  55 , as described above. Further, the suction ports  53 ,  54  are provided on the one end side in the second direction of the suction cap  55 . With this, it is possible to efficiently suck the ink flowed and gathered from the other end side to the one end side of the suction cap  55 , owing to the action of surface tension. 
     In the embodiment, the outer frame section  50  which supports the suction cap  55  and the maintenance base  57  in which the outer frame section  50  is installable are provided on the printer  2 . Further, the coil spring  75  is provided between the maintenance base  57  and the bottom surface of the outer frame section  50 . With this construction, the outer frame section  50  is arranged with a predetermined clearance with respect to the maintenance base  57  so that the outer frame section  50  is freely rockable in each of the first, second and third directions. With this, it is possible to rockably support the suction cap  55  three-dimensionally via the outer frame section  50 , and to assuredly realize a construction capable of efficiently suppressing the dirtying of the nozzle surface  30 . 
     Further, in the embodiment, the groove portions  74  are formed in the maintenance base  57  to regulate the movement of the outer frame section  50  along the second direction, and to guide the projections  72 ,  73  respectively so that the outer frame section  50  moves in the third direction between the contact position at which the suction cap  55  is brought into contact with the nozzle surface  30  and the separate position at which the suction cap  55  is separated and away from the nozzle surface  30 . As shown in  FIG. 5 , each of the groove portions  74  is constructed so that the width size in the second direction has a reverse tapered shape in which the width size is widened (expanded) in a direction toward the contact position from the separate position (see FIG.  7 ) of the suction cap  55  along the third direction, namely widened upward in the third direction. With this, while the suction cap  55  is moving in the third direction to the side at which the suction cap  55  is brought into contact with the nozzle surface  30 , the suction cap is allowed to rockably move to a great extent in the second direction. Accordingly, the suction cap  55  is allowed to have a contact with the nozzle surface  30  while tolerating the variation in the install position of the nozzle surface  30 , whereas in a state other than the above-described contact state, the rocking (swinging) motion of the suction cap  55  is suppressed to be small. In such a manner, it is possible to support the suction cap  55  stably. 
     Further, in the embodiment, the discharge head  39  is supported by the carriage  38  to be movable in the scanning direction. In such a construction, the discharge head  39  is transported to the maintenance device  51  by the carriage  38  when the maintenance such as the above-described purge operation is performed by the maintenance device  51 . The abutting portion  37  is provided on the carriage  38 ; and the abutted portion  59  provided on the outer frame section  50  of the maintenance device  51  is brought into abutment with the abutting portion  37 , thereby making it possible to define the posture of the suction cap  55 . With this, even when the install position of the nozzle surface  30  is varied or deviated, the posture of the suction cap  55  is adjusted by the abutment function of the abutting portion  37  of the carriage  38 , thereby making it possible to bring the nozzle surface  30  into contact with the suction cap  55  in an appropriate facing relationship. 
     Although the printer using the four color inks (black, cyan, magenta and yellow inks) is exemplified in the embodiment, there is no limitation to this, and it is allowable to apply the present teaching to a printer using three color inks (cyan, magenta and yellow inks). In such a case, the deep color ink (second ink) may be the cyan or magenta ink, and the light color ink (first ink) may be the yellow ink, and a construction similar to that of the embodiment may be provided. Further, the present teaching is not limited only to the application in which the printing is performed on paper or sheet, and may be applicable to an ink discharge apparatus which performs printing on a substrate, etc. 
     Note that the present teaching can be carried out while being modified in various ways within a scope or range without changing the gist or substance of the present teaching.