Patent Publication Number: US-9421776-B2

Title: Recovery system for recording head and ink-jet recording apparatus including the same

Description:
INCORPORATION BY REFERENCE 
     The present application is based on Japanese Patent Application No. 2014-263990 filed on Dec. 26, 2014, the contents of which are hereby incorporated by reference. 
     BACKGROUND 
     The present disclosure relates to an ink-jet recording apparatus that performs recording by ejecting ink onto a recording medium such as a paper sheet, more particularly, to: a recovery system for a recording head that forcibly pushes out ink from an ejecting nozzle of the recording head, thereafter, wipes away the purged ink adhering to an ink ejecting surface by means of a wiper; and to an ink-jet recording apparatus that includes the recovery system. 
     As recording apparatuses such as a facsimile, a copy machine, a printer, ink-jet recording apparatuses which form an image by ejecting ink are widely used because they can form a high-definition image. 
     In such ink-jet recording apparatuses, there is a case where deterioration (curved fly) in linear traveling of ink, failed ink ejection and the like occur and printing performance of the recording head declines. As a cause of this, occurrence of a meniscus trouble is conceivable which is caused by that foreign mater such as paper powder, dust and debris occurring during a sheet (recording medium) conveyance time, a minuscule ink drop (hereinafter, called a mist) ejected along with an ink drop for image recording, and a bouncing mist, which occurs when the ink drop adheres to the recording medium, adheres to the ink ejecting surface of the recording head. Besides, decline in sealing performance during a cap mounting time caused by that the mist adheres to a cap mounting place and dries and occurrence of increased viscosity of the ink in the nozzle due to the sealing performance decline are also conceivable. 
     Because of this, a structure is used, in which to prevent: the drying of ink in the ejecting nozzle whose opening is formed through the ink ejecting surface of the recording head; and clogging of the nozzle caused by the thickened ink in the ejecting nozzle, the ink is forcibly pushed out (purged) from the nozzle, thereafter, the purged ink adhering to the ink ejecting surface (nozzle surface) is wiped away by means of a wiper to perform a recording head recovery process. 
     For example, a method is known, in which a wiper is pressed at a predetermined contact pressure against a portion of an ink ejecting surface of a recording head, where there is not a nozzle, to clean the ink ejecting surface. Specifically, as shown in  FIG. 35A , a wiper  103  is pressed substantially perpendicularly to a region (wiping start position) outside a nozzle region  102 , where ejecting nozzles are disposed, of an ink ejecting surface  101   a  of a recording head  101 . Next, as shown in  FIG. 35B ,  FIG. 35C , the wiper  103  is horizontally moved along the ink ejecting surface  101   a  in an arrow A direction to wipe away ink  104  on the nozzle region  102 , and as shown in  FIG. 35D , after the wiper  103  is made to leave the ink ejecting surface  101   a , the wiper  103  is horizontally moved in an arrow A′ direction and returned to the wiping start position. 
     But, according to the method shown in  FIG. 35A  to  FIG. 35D , as shown in  FIG. 36A , inks  104   a ,  104   b  respectively adhere to a side surface and tip end of the wiper  103  during a second wiping time. The inks  104   a ,  104   b  adhering to the side surface and tip end of the wiper  103  are exposed to air to become high in viscosity, and adhere to the ink ejecting surface  101   a  as shown in  FIG. 36B  and  FIG. 36C . 
     As described above, the wiping operation is repeated, whereby the ink  104   b  collects gradually near the wiping start position to form a large ink puddle. And, there is a disadvantage that this ink puddle falls on or contact the recording medium passing under the ink ejecting surface  101   a  to dirty a print surface. 
     To improve the disadvantage, a wiping mechanism for an ink-jet recording apparatus is known, which has two wipers that can successively contact the ink ejecting surface of the recording head wherein the preceding wiper wipes away the purged ink and the following wiper wipes away ink that remains near a wiping start position of the preceding wiper. 
     SUMMARY 
     A recovery system for a recording head according to an aspect of the present disclosure is a recovery system for a recording head that is provided with a nozzle region from which an ejecting nozzle for ejecting ink onto a recording medium is opened, and which includes a wiper, a drive mechanism, and a control portion. The wiper wipes away purged ink that is forcibly pushed out from the ejecting nozzle. The drive mechanism reciprocates the wiper along an ink ejecting surface that includes the nozzle region. The control portion controls the pushing-out and ejection of the ink from the ejecting nozzle and the operation of the drive mechanism. The control portion is able to execute a recording head recovery operation that includes: a first ink pushing-out operation that forcibly pushes out the ink from the ejecting nozzle and makes the purged ink adhere to the nozzle region; a first wiping operation that presses the wiper against a first position outside the nozzle region of the ink ejecting surface, thereafter, moves the wiper to the nozzle region in a first direction along the ink ejecting surface with the wiper pressed against the ink ejecting surface, thereby wipes away the purged ink, and moves the wiper to a second position opposite to the first position with respect to the nozzle region; and a second wiping operation that moves the wiper from a position opposite to the first position with respect to the nozzle region to a position on the first position side with respect to the nozzle region with the wiper pressed against the ink ejecting surface. The wiper includes: a first wiping surface disposed to face in the first direction; a second wiping surface disposed to face in a second direction opposite to the first direction; and an upper surface disposed between the first wiping surface and the second wiping surface. The first wiping surface includes a first upper end portion that contacts the ink ejecting surface when the wiper moves in the first direction in the first wiping operation, the second wiping surface includes a second upper end portion that contacts the ink ejecting surface when the wiper moves in the second direction in the second wiping operation, and the upper surface is provided with a convex portion, which is rectangular in a side view, between the first upper end portion and the second upper end portion, and provided with a first step portion, which becomes higher from the first upper end portion to the second upper end portion, between the first upper end portion and the convex portion. 
     Still other objects of the present disclosure and specific advantages obtained by the present disclosure will become more apparent from the following description of embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view showing a structure of an ink-jet recording apparatus according to a first embodiment of the present disclosure. 
         FIG. 2  is a view of a first conveyance unit and a recording portion of the ink-jet recording apparatus shown in  FIG. 1  seen from above. 
         FIG. 3  is a view of the recording portion seen from diagonally above. 
         FIG. 4  is a view of a recording head that composes a line head of the recording portion. 
         FIG. 5  is a view of the recording head seen from an ink ejecting surface side. 
         FIG. 6  is a view of a wiping mechanism incorporated in a maintenance unit seen from diagonally above. 
         FIG. 7  is a view of a carriage composing the wiping mechanism seen from diagonally above. 
         FIG. 8  is a view showing a structure of a wiper. 
         FIG. 9  is a view showing a structure of a wiper upper portion seen from a wiper width direction. 
         FIG. 10  is a view showing a support frame composing the wiping mechanism seen from diagonally above. 
         FIG. 11  is a view showing a state in which the wiping mechanism is removed from a unit housing of a maintenance unit. 
         FIG. 12  is a view of a step-up/down mechanism disposed in the unit housing, that is, a view showing a state in which a lift member is in a horizontal state. 
         FIG. 13  is a view of the step-up/down mechanism disposed in the unit housing, that is, a view showing a state in which the lift member moves upright from the state of  FIG. 12 . 
         FIG. 14  is a view of the lift member that composes the step-up/down mechanism. 
         FIG. 15  is a view showing a state in which the maintenance unit is positioned under the recording portion. 
         FIG. 16  is a view showing a carriage, the wiper, the support frame, and the step-up/down mechanism in the maintenance unit in the state of  FIG. 15 . 
         FIG. 17  is a view showing a state in which the support frame and the carriage are stepped up by the step-up/down mechanism from the state of  FIG. 16  and the wiper is positioned to abut the ink ejecting surface. 
         FIG. 18  is a view of the recording head showing a state in which the wiper is positioned under a first position. 
         FIG. 19  is a view of the recording head seeing the ink ejecting surface in the state of  FIG. 18  from under. 
         FIG. 20  is a view of the recording head showing a state in which the wiper is moved in an arrow A direction with the wiper pressed against the ink ejecting surface. 
         FIG. 21  is a view showing a state of the wiper in which the wiper is being moved in the arrow A direction with pressed against the ink ejecting surface. 
         FIG. 22  is a view of the recording head showing a state in which the wiper is moved from the state of  FIG. 20  to a second position. 
         FIG. 23  is a view of the recording head showing a state in which the wiper is made to leave the ink ejecting surface at the second position. 
         FIG. 24  is a view of the recording head showing a state in which the wiper is moved in an arrow A′ direction from the state of  FIG. 23 . 
         FIG. 25  is a view of the recording head showing a state in which purged ink is pushed out from the state of  FIG. 24 . 
         FIG. 26  is a view of the recording head showing a state in which the wiper is pressed against the ink ejecting surface, thereafter, moved in the arrow A′ direction from the state of  FIG. 25 . 
         FIG. 27  is a view showing a state of the wiper in which the wiper is being moved in the arrow A′ direction with pressed against the ink ejecting surface. 
         FIG. 28  is a view of the recording head showing a state in which the wiper is further moved in the arrow A′ direction from the state of  FIG. 26  and the purged ink contacts remaining ink. 
         FIG. 29  is a view of the recording head showing a state in which the wiper is moved from the state of  FIG. 28  to an end edge on a downstream side in the arrow A′ direction. 
         FIG. 30  is a view showing a state in which the support frame and the carriage are stepped down by the step-up/down mechanism and the wiper leaves the ink ejecting surface. 
         FIG. 31  is a view of the recording head showing a state in which the wiper is made to leave the ink ejecting surface. 
         FIG. 32  is a view showing a wiper used in an ink-jet recording apparatus according to a second embodiment of the present disclosure. 
         FIG. 33  is a view showing, from a wiper width direction, a structure of an upper portion of the wiper used in the ink-jet recording apparatus according to the second embodiment of the present disclosure. 
         FIG. 34  is a view showing a structure of a cleaning mechanism disposed in an ink-jet recording apparatus according to a third embodiment of the present disclosure. 
         FIG. 35A  is a view showing a conventional wiping mechanism that makes a wiper contact an ink ejecting surface at a predetermined contact pressure from a substantially perpendicular direction and cleans the ink ejecting surface of a recording head, that is, a view showing a state in which the wiper is positioned under a wiping start position. 
         FIG. 35B  is a view of the recording head showing a state in which the wiper is moved from the state of  FIG. 35A  to a nozzle region while making the wiper contact the ink ejecting surface. 
         FIG. 35C  is a view of the recording head showing a state in which the wiper is further moved from the state of  FIG. 35B  to pass through the nozzle region. 
         FIG. 35D  is a view of the recording head showing a state in which the wiper is made to leave the ink ejecting surface from the state of  FIG. 35C . 
         FIG. 36A  is a view of the recording head showing a state in which the wiper is positioned under the wiping start position to perform a second wiping by using the conventional wiping mechanism shown in  FIG. 35A . 
         FIG. 36B  is a view of the recording head showing a state in which the wiper is made to contact the ink ejecting surface from the state of  FIG. 36A . 
         FIG. 36C  is a view of the recording head showing a state in which the wiper is moved from the state of  FIG. 36B  toward the nozzle region while making the wiper contact the ink ejecting surface. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present disclosure are described with reference to the drawings. 
     (First Embodiment) 
     As shown in  FIG. 1 , a sheet feeding tray  2  storing paper sheets S (recording media) is disposed in a left portion of an ink-jet recording apparatus  100  according to a first embodiment of the present disclosure. One end of the sheet feeding tray  2  is provided with a sheet feeding roller  3 , which feeds the sheets S stored in the sheet feeding tray  2  one after another beginning with the uppermost sheet S to a first conveyance unit  5  described later, and a driven roller  4  that is pressed against the sheet feeding roller  3  and driven to rotate. 
     The first conveyance unit  5  and a recording portion  9  are disposed downstream (right of  FIG. 1 ) from the sheet feeding roller  3  and driven roller  4  with respect to a sheet conveyance direction (arrow X direction). The first conveyance unit  5  has a structure which includes a first drive roller  6 , a first driven roller  7 , and a first conveyance belt  8  mounted on the first drive roller  6  and first driven roller  7 , wherein the first drive roller  6  is driven to rotate in a clockwise direction based on a control signal from a control portion  110  of the ink-jet recording apparatus  100 , whereby the sheet S held by the first conveyance belt  8  is conveyed in the arrow X direction. 
     The recording portion  9  includes a head housing  10 , line heads  11 C,  11 M,  11 Y, and  11 K which are held by the head housing  10 . These line heads  11 C to  11 K are supported at a height to form a predetermined distance (e.g., 1 mm) from a conveyance surface of the first conveyance belt  8 , and as shown in  FIG. 2  and  FIG. 3 , a plurality of recording heads  17   a  to  17   c  (here, three) are arranged in a staggering pattern along a sheet width direction (vertical direction of  FIG. 2 ) perpendicular to the sheet conveyance direction. In the meantime,  FIG. 3  shows a state of the recording portion  9  seen from behind  FIG. 1  (above  FIG. 2 ), and the arrangement of the line heads  11 C to  11 K is reverse in  FIG. 1  and  FIG. 2 . 
     As shown in  FIG. 4  and  FIG. 5 , ink ejecting surfaces F of the recording heads  17   a  to  17   c  are each provided with nozzle regions R where many ejecting nozzles  18  (see  FIG. 2 ) are arranged. In the meantime, the recording heads  17   a  to  17   c  have the same shape and structure. Accordingly, in  FIG. 4  and  FIG. 5 , one drawing represents the recording heads  17   a  to  17   c.    
     The recording heads  17   a  to  17   c  composing each line head  11 C to  11 K are supplied with four color inks (cyan, magenta, yellow, and black) stored in respective ink tanks (not shown) corresponding to the respective line heads  11 C to  11 K. 
     By means of control signals from the control portion  110  (see  FIG. 1 ), each recording head  17   a  to  17   c  ejects ink, in accordance with image data received from an external computer, from the ink ejecting nozzles  18  to the sheet S that is attracted and held on the conveyance surface of the first conveyance belt  18 . In this way, the four color inks of cyan, magenta, yellow and black are superimposed, whereby a color image is formed on the sheet S on the sheet conveyance belt  8 . 
     Besides, to prevent defective ink ejection caused by drying or clogging of the recording heads  17   a  to  17   c , when starting a print operation after a long period suspension, a purge is executed to push out thickened ink from the ejecting nozzles  18  of all the recording heads  17   a  to  17   c , and between the print operations, a purge is executed to push out thickened ink present in the ejecting nozzles  18  from the ejecting nozzles  18  of some of the recording heads  17   a  to  17   c  whose ink ejecting amount is less than a predetermined value, thereby preparing for the next print operation. 
     Back to  FIG. 1 , a second conveyance unit  12  is disposed downstream (right of  FIG. 1 ) from the first conveyance unit  5  in the sheet conveyance direction. The second conveyance unit  12  includes a second drive roller  13 , a second driven roller  14 , and a second conveyance belt  15  mounted on the second drive roller  13  and second driven roller  14 , wherein the second drive roller  13  is driven to rotate in a clockwise direction, whereby the sheet S held by the second conveyance belt  15  is conveyed in the arrow X direction. 
     The sheet S on which an ink image is formed by the recording portion  9  is conveyed to the second conveyance unit  12 , and during passing through the second conveyance unit  12 , the ink ejected to the sheet S surface is dried. Besides, a maintenance unit  19  and a cap unit  90  are disposed under the second conveyance unit  12 . When performing the above purge, the maintenance unit  19  moves under the recording portion  9 , wipes away the ink which is pushed out from the ink ejecting nozzles  18  of the recording heads  17   a  to  17   c  and adheres to the ink ejecting surface F, and collects the wiped ink. When capping the ink ejecting surface F (see  FIG. 4 ) of the recording heads  17   a  to  17   c , the cap unit  90  horizontally moves under the recording portion  9 , further, moves upward to be mounted on a lower surface of the recording heads  17   a  to  17   c . In the meantime, a detailed structure of the maintenance unit  19  is described later. 
     Besides, a delivery roller pair  16 , which delivers the sheet S on which an image is recorded to outside an apparatus main body, is disposed downstream from the second conveyance unit  12  with respect to the sheet conveyance direction, and a delivery tray (not shown), in which the sheet S delivered to outside the apparatus main body is loaded, is disposed downstream from the delivery roller pair  16 . 
     The maintenance unit  19  is mounted with a wiping mechanism  30  shown in  FIG. 6 . The wiping mechanism  30  is composed of a substantially rectangular carriage  31  to which a plurality of wipers  35   a  to  35   c  (see  FIG. 7 ) are fixed, and a support frame  40  that supports the carriage  31 . Rail portions  41   a ,  41   b  are formed on opposing end edges of an upper surface of the support frame  40 , and slide rollers  36  disposed at four corners of the carriage  31  abut the rail portions  41   a ,  41   b , whereby the carriage  31  is supported slidably in an arrow AA′ direction with respect to the support frame  40 . 
     As shown in  FIG. 7 , the carriage  31  is formed into a frame shape by first stays  32   a,    32   b  that slidably engage with the rail portions  41   a ,  41   b  of the support frame  40  via the slide rollers  36 , and second stays  33   a ,  33   b , and  33   c  that are fixed between the first stays  32   a ,  32   b  like bridges. 
     The first stay  32   a  is provided with rack teeth  38  that mesh with an input gear  43  (see  FIG. 6 ) held by the support frame  40 . When the input gear  43  rotates in forward and backward directions, the carriage  31  reciprocates in a horizontal direction (arrow AA′ direction of  FIG. 6 ) along the support frame  40 . In the meantime, a drive mechanism of the present disclosure is composed of the rack teeth  38  and the input gear  43 . 
     The wipers  35   a  to  35   c  are members that wipe away the ink pushed out from the ejecting nozzles  18  of the respective recording heads  17   a  to  17   c . The wipers  35   a  to  35   c  are pressed from substantially vertical directions against positions outside the nozzle region R (see  FIG. 5 ) from which nozzle surfaces of the ejecting nozzles  18  are exposed, and clean the ink ejecting surface F including the nozzle region R in a predetermined direction (arrow AA′ direction of  FIG. 6 ) in accordance with the movement of the carriage  31 . 
     Four wipers  35   a  are fixed to the second stay  33   a  at substantially equal intervals, likewise, four wipers  35   b  are fixed to the second stay  33   b  at substantially equal intervals, and four wipers  35   c  are fixed to the second stay  33   c  at substantially equal intervals. The wipers  35   a ,  35   c  are respectively disposed at positions corresponding to the left and right recording heads  17   a ,  17   c  (see  FIG. 3 ) that compose each line head  11  C to  11 K. Besides, the wiper  35   b  is disposed at a position corresponding to the central recording head  17   b  (see  FIG. 3 ) that composes each line head  11  C to  11 K, is deviated and fixed a predetermined distance away from the wipers  35   a ,  35   c  in a direction perpendicular to the movement direction (arrow AA′ direction of  FIG. 6 ) of the carriage  31 . 
     As shown in  FIG. 8  and  FIG. 9 , each wiper  35   a  to  35   c  includes: a first wiping surface  35   d  that is disposed to face in the A direction (first direction); a second wiping surface  35   e  that is disposed to face in a direction (second direction) opposite to the A direction; and an upper surface  35   f  that is disposed between the first wiping surface  35   d  and the second wiping surface  35   e.    
     The first wiping surface  35   d  wipes away purged ink  22   b  (see  FIG. 18 ), which is pushed out by a first ink pushing-out operation described later, during a first wiping operation time described later. A first upper end portion  35   g  of the first wiping surface  35   d  is pressed against the ink ejecting surface F when the wipers  35   a  to  35   c  move in the arrow A direction in the first wiping operation. 
     The second wiping surface  35   e  wipes away purged ink  22   c  (see  FIG. 25 ), which is pushed out by a second ink pushing-out operation described later, during a second wiping operation time described later. A second upper end portion  35   h  of the second wiping surface  35   e  is pressed against the ink ejecting surface F when the wipers  35   a  to  35   c  move in a direction (arrow A′ direction) opposite to the arrow A direction in the second wiping operation. 
     The upper surface  35   f  is provided with a convex portion C, which protrudes upward and is rectangular in a side view, between the first upper end portion  35   g  and the second upper end portion  35   h . A first step portion L 1 , which becomes higher (rises) in a direction from the first upper end portion  35   g  to the second upper end portion  35   h , is formed between the first upper end portion  35   g  and the convex portion C, and a second step portion L 2 , which becomes lower (declines) in the direction from the first upper end portion  35   g  to the second upper end portion  35   h , is formed between the convex portion C and the second upper end portion  35   h . In the meantime, the convex portion C (first step portion L 1 , second step portion L 2 ) does not contact the ink ejecting surface F when the wipers  35   a  to  35   c  move in the arrow AA′ direction in the first wiping operation and second wiping operation that are described later. 
     For example, the wipers  35   a  to  35   c  are each formed to have a width of about 2.5 mm when seeing from the arrow A direction and a width (distance between the first wiping surface  35   d  and the second wiping surface  35   e ) of about 1.0 mm in a cross-sectional view. Besides, the convex portion C is formed into a square that has an edge length of about 0.5 mm in a cross-sectional view. 
     As shown in  FIG. 7 , gap rollers  37  are dispose at four positions of upper surfaces of the second stays  33   a ,  33   c . When the wiping mechanism  30  is stepped up toward the recording portion  9  to perform the wiping operation for the ink ejecting surface F of the recording heads  17   a  to  17   c  by means of the wipers  35   a  to  35   c , the gap rollers  37  abut the head housing  10  of the recording portion  9  to keep a contact state of the wipers  35   a  to  35   c  with the ink ejecting surface F constant. 
     As shown in  FIG. 10 , the upper surface of the support frame  40  is provided with an ink collection tray  44  for collecting the wasted ink that is wiped away from the ink ejecting surface F by the wipers  35   a  to  35   c . At a substantially central portion of the ink collection tray  44 , a groove portion  44   a  is formed along an extension direction of the second stays  33   a  to  33   c , and tray surfaces  44   b ,  44   c  on both sides of the groove portion  44   a  have a descending gradient toward the groove portion  44   a . The groove portion  44   a  is provided therein with ink discharging holes  44   d , and a bottom surface of the groove portion  44   a  has a descending gradient toward the ink discharging holes  44   d.    
     The wasted ink, which is wiped away from the ink ejecting surface F by the wipers  35   a  to  35   c  and falls to the tray surfaces  44   b  and  44   c , is collected in the groove portion  44   a,  further, flows in the groove portion  44   a  to the ink discharging holes  44   d . Thereafter, the wasted ink is collected by a wasted ink collection tank (not shown) via an ink collection path (not shown) that is connected to the ink discharging holes  44   d.    
     Next, a step-up/down mechanism  50  for stepping-up/down the wiping mechanism  30  of the present embodiment is described. The maintenance unit  19  includes a unit housing  45  shown in  FIG. 11 , the wiping mechanism  30  (see  FIG. 6 ) disposed in the unit housing  45 , and the step-up/down mechanism  50  disposed in the unit housing  45 . As shown in  FIG. 11  and  FIG. 12 , on a bottom surface  45   a  of the unit housing  45 , the step-up/down mechanisms  50 , in which two lift members  50   a  are fixed to both ends of a shaft  50 , are disposed in pairs along opposing side surfaces  45   b ,  45   c  in the movement direction (arrow AA′ direction of  FIG. 6 ) of the carriage  31 . In other words, the step-up/down mechanisms  50  are disposed at positions opposing both ends (both upper and lower end portions of  FIG. 2 ) of the recording portion  9  in the width direction of the head housing  10 . In the meantime, in  FIG. 11 , the step-up/down mechanism  50  near the side surface  45   c  is not shown. Besides, a side surface  45   d  of the unit housing  45  abutting the side surfaces  45   b ,  45   c  of the unit housing  45  is provided with a motor  47 , and a drive transmission shaft  48  that transmits rotation force of the motor  47  to the shaft  50   b.    
     As shown in  FIG. 14 , a lower end portion of the lift member  50   a  is fixed to the shaft  50   b , and the lift member  50   a  pivots in accordance with rotation of the shaft  50   b . A pushing-up roller  53  is rotatably disposed on an upper end portion of the lift member  50   a . The pushing-up roller  53  is biased by a coil spring  55  in a direction (upward direction of  FIG. 14 ) leaving the shaft  50   b.    
     From a state of  FIG. 12 , when the shaft  50   b  of the right step-up/down mechanism  50  is rotated in a clockwise direction and the shaft  50   b  of the left step-up/down mechanism  50  is rotated in a counterclockwise direction, the lift member  50   a  fallen inside the unit housing  45  rises in an outward direction (arrow B direction), In this way, the lift member  50   a  is switched from a horizontal state to an upright state (state of  FIG. 13 ) to step up the carriage  31  together with the support frame  40 . 
     On the other hand, from a state of  FIG. 13 , when the shaft  50   b  of the right step-up/down mechanism  50  is rotated in the counterclockwise direction and the shaft  50   b  of the left step-up/down mechanism  50  is rotated in the clockwise direction, the lift member  50   a  falls in an inward direction (arrow B′ direction) of the unit housing  45 , In this way, the lift member  50   a  is switched from the upright state to the horizontal state (state of  FIG. 12 ) to step down the carriage  31  together with the support frame  40 . 
     Next, a recovery operation of the recording heads  17   a  to  17   c  by means of the wiping mechanism  30  of the ink-jet recording apparatus  100  according to the present embodiment is described. In the meantime,  FIG. 16 ,  FIG. 17 , and  FIG. 30  each show a state in which the recording portion  9  and the maintenance unit  19  are seen from a downstream side (left of  FIG. 15 ) in the sheet conveyance direction. Besides, the support frame  40  is illustrated like a plate in a simplified manner, and as to the unit housing  45 , only the bottom surface  45   a  is illustrated. Besides, the recovery operation of the recording heads  17   a  to  17   c  and the cap unit mounting operation described later are executed by controlling operations of the recording heads  17   a  to  17   c , wiping mechanism  30 , step-up/down mechanism  50  and the like based on control signals from the control portion  110  (see  FIG. 1 ). 
     In a case where the recovery operation of the recording heads  17   a  to  17   c  is performed, first, as shown in  FIG. 15 , the first conveyance unit  5  located under the recording portion  9  is stepped down. And, the maintenance unit  19  disposed under the second conveyance unit  12  is moved horizontally to be positioned between the recording portion  9  and the first conveyance unit  5 . In this state, as shown in  FIG. 16 , the lift member  50   a  of the step-up/down mechanism  50  is in the horizontal state, and the wipers  35   a  to  35   c  fixed to the carriage  31  are spaced away from the ink ejecting surface F of the recording heads  17   a  to  17   c.    
     (First Ink Pushing-Out Operation) 
     Previous to the wiping operation (first wiping operation described later), the ink  22  is supplied to the recording heads  17   a  to  17   c . As shown in  FIG. 18 , the supplied ink  22  is forcibly pushed out (purged) from the ejecting nozzles  18 . The ink having high viscosity, foreign matter and air bubbles in the ejecting nozzles  18  are discharged by the purge operation, whereby it is possible to recover the recording heads  17   a  to  17   c . During this time, as shown in  FIG. 19 , the purged ink  22  is pushed out onto the ink ejecting surface F along the shape of the nozzle region R where the ejecting nozzles  18  are present. 
     (First Wiping Operation) 
     The wipers  35   a  to  35   c  are made to contact a first position P 1  of the ink ejecting surface F of the recording heads  17   a  to  17   c  outside the nozzle region R at a predetermined pressure. Specifically, as shown in  FIG. 17  and  FIG. 18 , the shaft  50   b  of the step-up/down mechanism  50  is rotated to make the lift member  50   a  rise upright in the arrow B direction, whereby the support frame  40  and the carriage  31  are stepped up. During this time, gap rollers  37  disposed on the carriage  31  are pressed against a lower surface of the head housing  10  by the bias force of the coil spring  55  (see  FIG. 14 ) of the lift member  50   a.  Accordingly, it is always possible to press the wipers  35   a  to  35   c  against the ink ejecting surface F at a constant pressure. 
     From the state in which tip ends of the wipers  35   a  to  35   c  are in tight contact with the ink ejecting surface F, the input gear  43  (see  FIG. 6 ) is rotated forward to move the carriage  31  in the arrow A direction of  FIG. 17 , whereby also the wipers  35   a  to  35   c  supported by the carriage  31  move, with pressed against the ink ejecting surface F, in the direction (left direction, first direction, arrow A direction) to the nozzle region R along the ink ejecting surface F as shown in  FIG. 20 . An upward force acts on the support frame  40  by means of the step-up/down mechanism  50 . Accordingly, the carriage  31  moves in the arrow A direction while keeping the state in which the gap rollers  37  are pressed against the head housing  10 . 
     At this time, as shown in  FIG. 20 , the remaining ink  22   a , which remains on the tip ends (upper surfaces  35   f ) of the wipers  35   a  to  35   c  during the previous recovery operation time of the recording heads and is exposed to air for a long time to become high in viscosity, adheres to the first position P 1  of the ink ejecting surface F and leaves the tip ends of the wipers  35   a  to  35   c.    
     In the meantime, as shown in  FIG. 21 , when the wipers  35   a  to  35   c  move in the arrow A direction in the first wiping operation, the convex portions C (first step portion L 1 , second step portion L 2 ) do not contact the ink ejecting surface F. 
     And, as shown in  FIG. 22 , the wipers  35   a  to  35   c  moves in the left direction (arrow A direction) wiping away the purged ink  22   b  on the ink ejecting surface F, and on arriving at a position (second position P 2 , left end edge) opposite to the first position P 1  with respect to the nozzle region R, the movement in the left direction is stopped. In the meantime, most of the wasted ink wiped away by the wipers  35   a  to  35   c  is collected by the ink collection tray  44  (see  FIG. 10 ). 
     (Leaving Operation) 
     After the execution of the first wiping operation, as shown in  FIG. 23 , the wipers  35   a  to  35   c  are made to leave the ink ejecting surface F. Specifically, by rotating backward the shaft  50   b  (see  FIG. 17 ) of the step-up/down mechanism  50 , the lift member  50   a  is pivoted in the arrow B′ direction and brought to the horizontal state, whereby the support frame  40  and the carriage  31  are stepped down. In the meantime, the upper surfaces  35   f  of the wipers  35   a  to  35   c  are each provided thereon with the first step portion L 1 . Accordingly, it is possible to alleviate the purged ink  22   b  on the first wiping surface  35   d  moving to the second wiping surface  35   e . Because of this, when making the wipers  35   a  to  35   c  leave the ink ejecting surface F, it is possible to reduce the amount of the purged ink  22   b  that adheres to the upper surfaces  35   f  of the wipers  35   a  to  35   c . Besides, the upper surfaces  35   f  of the wipers  35   a  to  35   c  are provided thereon with the first step portions L 1  and the wipers  35   a  to  35   c  are moved to the left end edge of the ink ejecting surface F in the first wiping operation, whereby when the wipers  35   a  to  35   c  are made to leave the ink ejecting surface F, it is sufficiently possible to alleviate the purged ink  22   b  remaining on the ink ejecting surface F. 
     (Moving Operation) 
     After the execution of the leaving operation, as shown in  FIG. 24 , the wipers  35   a  to  35   c  are moved horizontally. Specifically, the input gear  43  (see  FIG. 6 ) is rotated backward from the state of  FIG. 23  to move the carriage  31  in the arrow A′ direction, whereby as shown in  FIG. 24 , the wipers  35   a  to  35   c  supported by the carriage  31  move in the same direction (right direction) as the nozzle region R with respect to the second position P 2 . In the meantime, it is also possible to execute the second wiping operation described later without moving the wipers  35   a  to  35   c  in the right direction, but the wipers  35   a  to  35   c  are moved a little in the right direction, whereby in the second wiping operation, it is possible to alleviate the upper surfaces  35   f  of the wipers  35   a  to  35   c  contacting the left end portion (corner portion) of the ink ejecting surface F and damaging in the second wiping operation. 
     (Second Ink Pushing-Out Operation) 
     After the execution of the moving operation, the ink  22  is supplied to the recording heads  17   a  to  17   c . As shown in  FIG. 25 , the supplied ink  22  is forcibly pushed out (purged) from the ink ejecting nozzles  18 . In this way, like the first ink pushing-out operation, the purged ink  22   c  adheres to the ink ejecting surface F. 
     (Second Wiping Operation) 
     Thereafter, a wiping operation is performed which wipes away the purged ink  22   c  and remaining ink  22   a  on the ink ejecting surface F. Specifically, the shaft  50   b  of the step-up/down mechanism  50  is rotated to make the lift member  50   a  rise upright in the arrow B direction, whereby the support frame  40  and the carriage  31  are stepped up. In this way, the wipers  35   a  to  35   c  are made to contact a left position of the ink ejecting surface F of the recording heads  17   a  to  17   c  with respect to the nozzle region R at a predetermined pressure. And, the input gear  43  (see  FIG. 6 ) is rotated backward to move the carriage  31  in the arrow A′ direction (right direction, second direction), whereby as shown in  FIG. 26 , the wipers  35   a  to  35   c  move in a direction (right direction) to the nozzle region R along the ink ejecting surface F with the wipers  35   a  to  35   c  pressed against the ink ejecting surface F. 
     In the meantime, as shown in  FIG. 27 , in the second wiping operation, when the wipers  35   a  to  35   c  move in the arrow A′ direction, the convex portions C (first step portion L 1 , second step portion L 2 ) do not contact the ink ejecting surface F. 
     And, the purged ink  22   c  pushed out by the second ink pushing-out operation and the remaining ink  22   a  adhering to the first position P 1  are wiped away. At this time, as shown in  FIG. 28 , when the purged ink  22   c  wiped away by the wipers  35   a  to  35   c  contacts the remaining ink  22   a , the remaining ink  22   a  merges into the purged ink  22   c  and the viscosity of the remaining ink  22   a  declines. 
     Thereafter, the wipers  35   a  to  35   c  each move to an end edge (right end edge of  FIG. 29 ) of the ink ejecting surface F of the recording heads  17   a  to  17   c , and most of the wasted ink wiped away by the wipers  35   a  to  35   c  flows down to be collected by the ink collection tray  44  (see  FIG. 10 ). And, as shown in  FIG. 30 , the shaft  50   b  of the step-up/down mechanism  50  is rotated to make the lift member  50   a  fall in the arrow B′ direction, whereby the wipers  35   a  to  35   c  are evacuated downward from the ink ejecting surface F of the recording heads  17   a  to  17   c  to return the maintenance unit  19  to the state of  FIG. 16 . 
     In the meantime, as shown in  FIG. 9 , the upper surfaces  35   f  of the wipers  35   a  to  35   c  are each provided with the second step portion L 2 . Accordingly, as shown in  FIG. 31 , it is possible to alleviate the purged ink  22   c  on the second wiping surface  35   e  moving to the first wiping surface  35   d . Because of this, when the wipers  35   a  to  35   c  are made to leave the ink ejecting surface F, it is possible to reduce the amount of the purged ink  22   c  that adheres to the upper surfaces  35   f  of the wipers  35   a  to  35   c . Besides, the upper surfaces  35   f  of the wipers  35   a  to  35   c  are provided thereon with the second step portions L 2  and in the second wiping operation, the wipers  35   a  to  35   c  are moved to the right end edge of the ink ejecting surface F, whereby when the wipers  35   a  to  35   c  are made to leave the ink ejecting surface F, it is possible to sufficiently alleviate the purged ink  22   c  remaining on the ink ejecting surface F. 
     Lastly, the maintenance unit  19  positioned between the recording portion  9  and the first conveyance unit  5  is moved horizontally to be positioned under the second conveyance unit  12 , and the first conveyance unit  5  is stepped up to a predetermined position to end the recovery operation of the recording heads  17   a  to  17   c.    
     In a case where the cap unit  90  is mounted onto the recording heads  17   a  to  17   c , first, as shown in  FIG. 15 , the first belt conveyance portion  5  disposed to oppose a lower surface of the recoding portion  9  is stepped down. And, the cap unit  90  disposed under the second belt conveyance portion  12  is moved horizontally into between the recording portion  9  and the first belt conveyance portion  5  to be positioned at a position opposing the recording portion  9 . 
     Next, the first belt conveyance portion  5  is stepped up, whereby the cap unit  90  is pushed up. And, at a time the cap unit  90  comes into tight contact with the recording heads  17   a  to  17   c , the stepping-up of the first belt conveyance portion  5  is stopped to complete the mounting of the cap unit  90 . 
     In the present embodiment, as described above, after the execution of the first wiping operation, by executing the second wiping operation in which the wipers  35   a  to  35   c  are moved along the ink ejecting surface F from the position opposite to the first position P 1  with respect to the nozzle region R to the position on the first position P 1  side with respect to the nozzle region R, it is possible to wipe away the remaining ink  22   a  adhering to the first position P 1  by means of the wipers  35   a  to  35   c . In this way, it is possible to alleviate the remaining ink  22   a  collecting on the ink ejecting surface F. Accordingly, it is possible to alleviate a large ink puddle forming. Besides, unlike the case of disposing the two wipers  35   a  to  35   c  that successively contact the ink ejecting surface F (the ink-jet recording apparatus that has the above two wipers), it is possible to alleviate the number of the wipers  35   a  to  35   c  increasing. Accordingly, it is possible to alleviate a structure of the recovery system for the recording heads  17   a  to  17   c  becoming complicated. 
     Besides, the upper surfaces  35   f  of the wipers  35   a  to  35   c  are each provided thereon with the convex portion C, and the first step portion L 1 , which becomes higher in the direction from the first upper end portion  35   g  to the second upper end portion  35   h , is formed between the first upper end portion  35   g  and the convex portion C. In this way, it is possible to alleviate the ink  22  moving in the direction from the first upper end portion  35   g  to the second upper end portion  35   h  by means of the first step portion L 1 . Accordingly, it is possible to alleviate the ink  22 , which is wiped away by the first wiping surface  35   d , adhering to the second upper end portion  35   h . Because of this, at the start time of the second wiping operation, it is possible to alleviate the ink  22  on the second upper end portion  35   h  being stretched and adhering to the ink ejecting surface F. In the meantime, in a case where only a small amount of the ink  22  adheres to the second upper end portion  35   h , if the second wiping operation is executed, the ink  22  is stretched to adhere to the ink ejecting surface F, and some amount of the ink is not wiped away and left. 
     Besides, the upper surfaces  35   f  of the wipers  35   a  to  35   c  are each provided thereon with the first step portion L 1 , whereby during the leaving operation time after the first wiping operation, it is possible to reduce the amount of the ink  22  that adheres to the upper surfaces  35   f  of the wipers  35   a  to  35   c  and to the ink ejecting surface F. 
     Besides, as described above, when the wiper  35   a  to  35   c  move in the arrow A direction (left direction) in the first wiping operation, the first step portions L 1  do not contact the ink ejecting surface F. In this way, only the first upper end portions  35   g  contact the ink ejecting surface F. Accordingly, it is possible to alleviate a contact pressure of the first upper end portion  35   g  against the ink ejecting surface F changing. 
     Besides, as described above, the upper surfaces  35   f  are each provided thereon with the second step portion L 2 , which becomes lower in the direction from the first upper end portion  35   g  to the second upper end portion  35   h , between the convex portion C and the second upper end portion  35   h . In this way, it is possible to alleviate the ink  22  moving from the second upper end portion  35   h  to the first upper end portion  35   g  by means of the second step portion L 2 . Because of this, during the leaving operation time after the second wiping operation, it is possible to reduce the amount of the ink  22  that adheres to the upper surfaces  35   f  of the wipers  35   a  to  35   c  and to the ink ejecting surface F. 
     Besides, as described above, when the wiper  35   a  to  35   c  move in the arrow A′ direction (right direction) in the second wiping operation, the second step portions L 2  do not contact the ink ejecting surface F. In this way, only the second upper end portions  35   h  contact the ink ejecting surface F. Accordingly, it is possible to alleviate a contact pressure of the second upper end portion  35   h  against the ink ejecting surface F changing. 
     Besides, as described above, in the second wiping operation, the wipers  35   a  to  35   c  are moved in the arrow A′ direction (right direction), whereby the wipers  35   a  to  35   c  wipe away the purged ink  22   c  pushed out during the second ink pushing-out operation time, thereafter, wipe away the remaining ink  22   a  adhering to the first position P 1 . In this way, when the wipers  35   a  to  35   c  wipe away the remaining ink  22   a , the purged ink  22   c , which is not high in viscosity, contacts the remaining ink  22   a  that is exposed to air for a long time to become high in viscosity. Accordingly, the remaining ink  22   a  merges into the purged ink  22   b  and the viscosity of the remaining ink  22   a  declines. Because of this, in the second wiping operation, it is possible to make it easy for the wipers  35   a  to  35   c  to wipe away the remaining ink  22   a  that adheres to the ink ejecting surface F. 
     Besides, as described above, after the execution of the first wiping operation, the leaving operation is executed which makes the wipers  35   a  to  35   c  leave the ink ejecting surface F. In this way, it is possible to temporarily eliminate bends (deformations) of the wipers  35   a  to  35   c  by means of the leaving operation. Accordingly, it is possible to easily press the second upper end portions  35   h  of the second wiping surfaces  35   e  of the wipers  35   a  to  35   c  against the ink ejecting surface F. 
     (Second Embodiment) 
     Next, with reference to  FIG. 32  and  FIG. 33 , the wipers  35   a  to  35   c , which are used in the ink-jet recording apparatus  100  according to a second embodiment of the present disclosure, are described. 
     In the second embodiment of the present disclosure, as shown in  FIG. 32  and  FIG. 33 , like the above first embodiment, the wipers  35   a  to  35   c  each include the first wiping surface  35   d , the second wiping surface  35   e , and the upper surface  35   f.    
     The upper surface  35   f  is provided thereon with the convex portion C which is rectangular in a side view. In the second embodiment, the convex portion C is formed to be coplanar with the second wiping surface  35   e , and the first step portion L 1 , which becomes higher in the direction from the first upper end portion  35   g  to the second upper end portion  35   h , is formed between the first upper end portion  35   g  and the convex portion C. In the meantime, when the wiper  35   a  to  35   c  move in the arrow A direction in the first wiping operation, the convex portions C (first step portion L 1 ) do not contact the ink ejecting surface F. 
     For example, the wipers  35   a  to  35   c  are each formed to have a width of about 2.5 mm when seeing from the arrow A direction and a width (distance between the first wiping surface  35   d  and the second wiping surface  35   e ) of about 1.5 mm in a cross-sectional view. Besides, the convex portion C is formed into a square that has an edge length of about 0.5 mm in a cross-sectional view. In other words, the distance between the first upper end portion  35   g  and the first step portion L 1  is about 1.0 mm, and the height of the first step portion L 1  is about 0.5 mm. 
     The other structures of the second embodiment and the recovery operation of the recording heads  17   a  to  17   c  are the same as the first embodiment. 
     In the present embodiment, as described above, the convex portions C of the wipers  35   a  to  35   c  are formed to be coplanar with the second wiping surfaces  35   e . Even in this case, it is possible to alleviate the ink  22  moving in the direction from the first upper end portion  35   g  to the second upper end portion  35   h  by means of the first step portion L 1 . Accordingly, it is possible to alleviate the ink  22 , which is wiped away by the first wiping surface  35   d,  adhering to the second upper end portion  35   h . Besides, it is possible to reduce the amount of the ink  22  which adheres to the upper surfaces  35   f  of the wipers  35   a  to  35   c  and to the ink ejecting surface F. 
     The other effects of the second embodiment are the same as the first embodiment. 
     (Third Embodiment) 
     Next, with reference to  FIG. 34 , the ink-jet recording apparatus  100  according to a third embodiment of the present disclosure is described. 
     In the third embodiment of the present disclosure, as shown in  FIG. 34 , the ink-jet recording apparatus  100  includes a cleaning mechanism  70  that cleans the upper surfaces  35   f  of the wipers  35   a  to  35   c . The cleaning mechanism  70  includes: a cleaning member  71  which is formed of a fiber web and the like and to which the ink  22  adhering to the upper surfaces  35   f  of the wipers  35   a  to  35   c  is transferred; a sending roller  72  around which the cleaning member  71  is wound; and a winding roller  73  that winds the cleaning member  71  sent out from the sending roller  72 . 
     Besides, in the third embodiment, after the execution of the second wiping operation of the recovery operation of the recording heads  17   a  to  17   c , the upper surfaces  35   f  of the wipers  35   a  to  35   c  are made to contact and leave the cleaning member  71  a plurality of times, whereby the ink  22  on the upper surfaces  35   f  of the wipers  35   a  to  35   c  is absorbed by the cleaning member  71 . In the meantime, in a case where the absorbing power of the cleaning member  71  declines, the winding roller  73  is rotated to enable the upper surfaces  35   f  of the wipers  35   a  to  35   c  to abut a clean transfer surface of the cleaning member  71 , whereby it is possible to recover the absorbing power of the cleaning member  71 . Accordingly, it is possible to sufficiently clean the upper surfaces  35   f  of the wipers  35   a  to  35   c.    
     The other structures of the third embodiment and the other recovery operation of the recording heads  17   a  to  17   c  are the same as the second embodiment. 
     In the present embodiment, as described above, the cleaning mechanism  70  is disposed which cleans the upper surfaces  35   f  of the wipers  35   a  to  35   c . In this way, it is possible to remove the ink  22  on the upper surfaces  35   f  of the wipers  35   a  to  35   c . Accordingly, it is possible to alleviate the ink  22 , which adheres to the wipers  35   a  to  35   c,  adhering to the ink ejecting surface F during the next recovery operation time. 
     The other effects of the third embodiment are the same as the second embodiment. 
     It should be considered that the embodiments disclosed this time are examples in all respects and are not limiting. The scope of the present disclosure is not indicated by the above description of the embodiments but by the claims, and all modifications within the scope of the claims and the meaning equivalent to the claims are covered. 
     For example, in the above embodiments, the first ink pushing-out operation is executed before the first wiping operation, but if it is before the wipers  35   a  to  35   c  enter the nozzle region R, the first ink pushing-out operation may be executed at the same time as the first wiping operation. 
     Besides, in the above embodiments, the second ink pushing-out operation is executed after the leaving operation, but may be executed before the leaving operation, and if it is before the wipers  35   a  to  35   c  enter the nozzle region R, the second ink pushing-out operation may be executed at the same time as the second wiping operation. 
     Besides, for example, in the above first embodiment, the example is described, in which the convex portions C of the wipers  35   a  to  35   c  are formed not to contact the ink ejecting surface F when the wipers  35   a  to  35   c  move in the arrow AA′ direction in the first wiping operation and second wiping operation, but the present disclosure is not limited to this. For example, the wipers  35   a  to  35   c  may be formed in such a manner that both the first upper end portion  35   g  and the convex portion C (first step portion L 1 ) contact the ink ejecting surface F when the wipers  35   a  to  35   c  move in the A′ direction in the first wiping operation. Besides, the wipers  35   a  to  35   c  may be formed in such a manner that both the second upper end portion  35   h  and the convex portion C (second step portion L 2 ) contact the ink ejecting surface F when the wipers  35   a  to  35   c  move in the A′ direction in the second wiping operation. However, to alleviate the contact pressure of the first upper end portion  35   g  and second upper end portion  35   h  against the ink ejecting surface F changing, it is preferable to form the wipers  35   a  to  35   c  in such a manner that the convex portion C does not contact the ink ejecting surface F when the wipers  35   a  to  35   c  move in the AA′ direction in the first wiping operation and second wiping operation. 
     Besides, as to the drive mechanism (rack teeth  38 , input gear  43 ) and the step-up/down mechanism  50 , it is possible to use another conventionally known drive mechanism and step-up/down mechanism. It is also possible to suitably set the number of the ejecting nozzles  18  of the recording heads  17   a  to  17   c , the nozzle interval and the like in accordance with the specifications of the ink-jet recording apparatus  100 . Besides, the number of recording heads is not especially limited, and for example, it is also possible to dispose the recording head  17  one, two, four or more for each line head  11 C to  11 K. 
     Besides, the present disclosure is also applicable to an ink-jet recording apparatus for single color printing that includes only one of the line heads  11 C to  11 K. In this case, the recording heads  17   a  to  17   c  are each disposed one. Accordingly, also the wipers  35   a  to  35   c  each may be fixed one to the carriage  31 .