Patent Publication Number: US-8534808-B2

Title: Liquid ejecting apparatus and cleaning method in liquid ejecting apparatus

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a liquid ejecting apparatus such as an ink jet type printer, for example, and a cleaning method in a liquid ejecting apparatus. 
     2. Related Art 
     Heretofore, as a liquid ejecting apparatus which ejects liquid onto a target, an ink jet type printer has become widely known. The printer is made so as to carry out printing (image formation) on the target by ejecting ink (liquid), which is supplied to a recording head (a liquid ejecting head), from nozzles formed in the recording head. 
     In such a printer, if the mixing-in of air bubbles, the rising of a meniscus, the thickening of ink, or the like occurs, satisfactory ejection of ink cannot be attained, thereby causing the lowering of printing quality. For this reason, in such a printer, for example, as described in JP-A-2007-152725, cleaning (pressurization cleaning) is performed by pressuring and supplying ink from the upstream side which is an ink cartridge side containing ink to the downstream side which is the recording head side, thereby discharging ink from the nozzle. 
     In such a printer, back pressure is applied to ink, thereby making a meniscus of ink be located in the vicinity of a nozzle orifice. As a configuration of applying back pressure to ink, in general, a one-way valve is used which allows passage of ink from the upstream side to the downstream side in a case where the downstream side has been decompressed. The one-way valve has a pressure chamber, in which a volume changes in accordance with a change in pressure on the downstream side, and if the downstream side is decompressed, the pressure chamber contracts, thereby opening the valve, whereas a valve closed state is maintained even if ink is pressurized and supplied from the upstream side. 
     For this reason, like the printer of JP-A-2007-152725, in the case of pressurizing and supplying ink from the cartridge side, thereby supplying it to the nozzle side, ink remains pressurized further in the downstream side than the one-way valve. 
     Further, in such a printer, ink mist which is generated accompanying the ejection of ink, or ink overflowed from the nozzle adheres to a nozzle formation face of the recording head, in which the nozzles are formed, whereby the nozzle formation face is contaminated. Accordingly, for example, as described in JP-A-2009-178867, wiping which sweeps the nozzle formation face by using a wiper is performed, thereby removing foreign materials adhered to the nozzle formation face. 
     Incidentally, ink supplied to the recording head forms a meniscus in the vicinity of the nozzle orifice and is ejected from the nozzle in accordance with the driving of a piezoelectric element. For this reason, if the wiper comes into contact with the nozzle formation face, there is a possibility that ink may flow out down the wiper. Accordingly, in the printer of JP-A-2009-178867, the contact between the wiper and ink is suppressed by performing wiping in a state where the meniscus is drawn into the nozzle by driving the piezoelectric element. 
     Incidentally, in a case where ink is pressurized further at the downstream side than the one-way valve, since a pressurizing force is also transmitted to the one-way valve, the pressure chamber expands, thereby accumulating the pressurizing force. For this reason, like the printer of JP-A-2007-152725, in a case where cleaning is performed by pressurizing ink further at the downstream side than the one-way valve, the back pressure of ink cannot be adjusted by the one-way valve, and further, the pressurizing force accumulated in the pressure chamber is transmitted to the nozzle side. Even after the end of cleaning, there is a fear that ink overflows from the nozzle, such that a lot of ink is wasted with the cleaning. 
     Further, in the printer described in JP-A-2009-178867, the meniscus of ink is made to be located in the vicinity of the nozzle orifice by a capillary force. Since ink is forced to the nozzle orifice side by the capillary force of the nozzle, in the case of raising the meniscus by driving the piezoelectric element, it is difficult to maintain the risen position. 
     Accordingly, as the manner of providing a suction force larger than the capillary force of the nozzle, the manner of suctioning ink by using a pump can be considered. However, in the case of providing a pump at a single flow path (liquid supply flow path) which communicates with a plurality of nozzles and suctions ink, thereby raising the meniscus, the more the distance from the pump to the nozzle is distant, the more difficult it is for the suction force of the pump to reach the nozzle. For this reason, the more the distance from the pump to the nozzle is distant, the more easily the position of the meniscus is lowered, so that variation occurs in position of the meniscus for each nozzle. 
     Therefore, if ink is supplied to the nozzle side after the end of wiping, in the nozzle in which the meniscus is maintained at the risen position, the meniscus moves to the vicinity of the nozzle orifice. On the other hand, in the nozzle in which the meniscus has descended, there is a possibility that ink may overflow from the nozzle. 
     SUMMARY 
     An advantage of some aspects of the invention is that it provides a liquid ejecting apparatus in which it is possible to perform wiping where outflow of liquid from a nozzle is suppressed, a liquid ejecting apparatus in which it is possible to perform cleaning where consumption of liquid after the end of the cleaning is suppressed, and a cleaning method in a liquid ejecting apparatus. 
     According to a first aspect of the invention, there is provided a liquid ejecting apparatus including: nozzles which eject liquid; a liquid supply flow path which supplies the liquid from a liquid supply source to the nozzles; a pump which suctions the liquid in the liquid supply flow path from a first position in the liquid supply flow path and discharges the liquid from the first position into the liquid supply flow path; a one-way valve which is provided at a second position which is further on the upstream side than the first position in the liquid supply flow path, and is opened in a case where a pressure chamber, in which a volume changes in accordance with a change in pressure on the downstream side, contracts in accordance with decompression on the downstream side, thereby allowing passage of the liquid from the liquid supply source side to the nozzle side; and a control unit which controls the driving of the pump so as to make the pump suction the liquid in the liquid supply flow path from the first position after making the pump discharge the liquid from the first position into the liquid supply flow path. 
     According to this configuration, by performing the discharge driving of the pump, it is possible to perform a cleaning process in which liquid is supplied to the nozzle side through the liquid supply flow path and then discharged from the nozzle. At this time, since the pump discharges liquid into the liquid flow path at the first position, discharge pressure also acts on the pressure chamber of the one-way valve provided at the second position. Then, in the one-way valve, the pressure chamber expands with a valve closing state maintained, and thereby accumulates a pressurizing force. However, since the pump performs suction driving after the discharge driving is performed, transmission of the pressurizing force to the nozzle side can be suppressed by suctioning liquid in the liquid supply flow path, thereby contracting the pressure chamber. Therefore, it is possible to perform cleaning where consumption of liquid after the end of the cleaning is suppressed. 
     In the liquid ejecting apparatus according to the above aspect of the invention, the pump may include a volume-variable liquid chamber which communicates with the inside of the liquid supply flow path, a volume-variable gas chamber which contains gas, and a volume changing section which changes the volumes of the liquid chamber and the gas chamber, and the control unit may control the volume changing section to make the pressure of the gas compressed by reducing the volume of the gas chamber act on the liquid in the liquid chamber, thereby making the pump perform discharge driving. 
     In a case where the viscosity of liquid has increased or a case where air bubbles have been mixed in liquid, the fluidity of the liquid decreases. In that respect, according to this configuration, by compressing gas in the gas chamber and also providing the pressure of the compressed gas to liquid in the liquid chamber, it is possible to vigorously discharge liquid into the liquid supply flow path. Since it is not necessary to provide a configuration of accumulating the pressurizing force of the pump, such as a valve, at the liquid supply flow path, an increase in the number of parts is suppressed, whereby it is possible to speed up the flow velocity of liquid. 
     In the liquid ejecting apparatus according to the above aspect of the invention, an amount of liquid that the pump can suction in accordance with the suction driving may be larger than an amount of change in the volume of the pressure chamber. 
     According to this configuration, since the pressure chamber expanded in accordance with the discharge driving of the pump can be contracted by the suction driving of the pump so as to become a minimal volume, transmission of the pressurizing force to the nozzle side can be suppressed. In a case where the pump has suctioned liquid equal to or greater than an amount of change in the pressure chamber, since the inside of the pressure chamber is decompressed, the one-way valve is opened, so that liquid is supplied from the upstream side into the pressure chamber. For this reason, it is possible to suppress consumption of liquid after cleaning and also adjust pressure further on the downstream side than the one-way valve in the liquid supply flow path. 
     According to a second aspect of the invention, there is provided a cleaning method in a liquid ejecting apparatus which includes nozzles which eject liquid, and a liquid supply flow path which supplies the liquid from a liquid supply source to the nozzles, the method including: suctioning the liquid in the liquid supply flow path from a first position in the liquid supply flow path; and discharging the liquid suctioned in the suctioning from the first position in the liquid supply flow path into the liquid supply flow path. 
     According to this configuration, the same working effects as those of the invention related to the liquid ejecting apparatus according to the first aspect can be obtained. 
     In the cleaning method in a liquid ejection apparatus according to the second aspect of the invention, the method may further include opening a one-way valve, after the suctioning, which is provided at a second position further on the upstream side than the first position in the liquid supply flow path and is opened in a case where a pressure chamber, in which a volume changes in accordance with a change in pressure on the downstream side, contracts in accordance with decompression on the downstream side, thereby allowing passage of the liquid from the liquid supply source side to the nozzle side. 
     In the cleaning method in a liquid ejection apparatus according to the second aspect of the invention, the method may further include closing the one-way valve after the liquid is discharged into the liquid supply flow path in the discharging. 
     In the cleaning method in a liquid ejection apparatus according to the second aspect of the invention, the method may further include suctioning the liquid in the liquid supply flow path from the first position in the liquid supply flow path after the liquid is discharged into the liquid supply flow path in the discharging. 
     According to a third aspect of the invention, there is provided a liquid ejecting apparatus including: a plurality of nozzles which ejects liquid; a liquid supply chamber which communicates with each of the plurality of nozzles, thereby supplying the liquid to each of the nozzles; a liquid supply flow path which supplies the liquid from a liquid supply source to the liquid supply chamber and is connected at a plurality of branched flow paths thereof to the liquid supply chamber; a pump which suctions the liquid in the liquid supply flow path and discharges the liquid into the liquid supply flow path; a wiping section which brings a wiper into contact with a nozzle formation face of a liquid ejecting head, in which the nozzles are formed, thereby sweeping the nozzle formation face; and a control unit which makes the wiping section sweep the nozzle formation face after the liquid is suctioned from the liquid supply flow path by making the pump perform suction driving, and thereafter, makes the pump perform discharge driving, thereby discharging the liquid to the liquid supply flow path. 
     For example, in the case of suctioning liquid by a single liquid supply flow path which is not branched, a difference in suction power which is transmitted to the respective nozzles become larger, so that variation occurs in the positions of the meniscuses M. In that respect, according to this configuration, since the liquid supply flow path is branched and connected to the liquid supply chamber, suction power can be transmitted to plural locations in the liquid supply chamber. Since the nozzle formation face can be swept by the wiping section in a state where the meniscus has risen in each nozzle, consumption of liquid accompanying the contact of the wiper with liquid can be suppressed. Since the meniscus rises in a state where variation in position has been reduced, it is possible to suppress the overflowing of liquid from the nozzle at the time of the discharge driving of the pump. Therefore, it is possible to perform wiping where outflow of liquid from the nozzle is suppressed. 
     In the liquid ejecting apparatus according to the third aspect of the invention, in the liquid supply chamber, at least one connection port, to which the downstream end of the liquid supply flow path is connected, may be formed for each of a plurality of areas sectioned along a longitudinal direction of the liquid supply chamber. 
     According to this configuration, since at least one connection port is formed for each of a plurality of areas in the liquid supply chamber, a possibility that the downstream ends of the liquid supply flow path may be disproportionately connected to the liquid supply chamber is reduced. Therefore, the bias of suction power which is exerted to the inside of the liquid supply chamber when the pump performs the suction driving is suppressed, so that variation in the positions of the meniscuses can be further reduced. 
     In the liquid ejecting apparatus according to the third aspect of the invention, in the liquid supply flow path, a connection position where the pump is connected may be further on the upstream side than a branching portion where the liquid supply flow path is branched. 
     According to this configuration, it is possible to transmit pressure to the liquid supply chamber through the branched liquid supply flow path by driving a single pump. Therefore, compared to a case where the pump is provided at each flow path which is further on the downstream side than the branching portion, the number of parts is reduced, so that a reduction in size of the liquid ejecting apparatus can be attained. 
     The liquid ejecting apparatus according to the third aspect of the invention may further include a flow path valve which is provided at a position which is further on the upstream side than a connection position of the pump in the liquid supply flow path, so as to be able to open and close the inside of the liquid supply flow path, wherein the control unit carries out suction driving of the pump in a state where the flow path valve has been closed. 
     According to this configuration, the pump performs the suction driving in a state where the flow path valve has been closed, whereby it is possible to suppress the inflow of liquid from the upstream side and suction liquid from the downstream side. Therefore, the amount of liquid which is supplied to the downstream side when the pump performs the discharge driving becomes approximately equal to the amount of liquid suctioned in accordance with the suction driving. For this reason, it is possible to reduce a possibility that liquid may overflow from the nozzle, and also to reduce a possibility that the nozzle formation face after wiping may be contaminated with liquid overflowed from the nozzle. 
     According to a fourth aspect of the invention, there is provided a wiping method in a liquid ejection apparatus which includes a plurality of nozzles which ejects liquid, a liquid supply chamber which communicates with each of the plurality of nozzles, and a liquid supply flow path which can supply the liquid from the upstream side which is a liquid supply source side to the downstream side which is the liquid supply chamber side and is connected at branched downstream ends thereof to the liquid supply chamber, the method including: suctioning the liquid in the liquid supply flow path by performing suction driving of a pump capable of suctioning the liquid in the liquid supply flow path and also capable of discharging the liquid into the liquid supply flow path; wiping a nozzle formation face of a liquid ejection head, in which the nozzles are formed, by bringing a wiper into contact with the nozzle formation face in a state where the liquid has been suctioned in the suctioning; and discharging the liquid suctioned in the suctioning into the liquid supply flow path by performing discharge driving of the pump. 
     According to this configuration, the same working effects as those of the invention related to the liquid ejecting apparatus according to the third aspect can be obtained. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a schematic diagram of a printer of an embodiment. 
         FIG. 2  is a schematic diagram of an ink supply system of a first embodiment. 
         FIG. 3  is a sectional schematic diagram as viewed in the direction of the arrow III-III of  FIG. 2 . 
         FIG. 4  is a schematic diagram of a maintenance pump in a standby state. 
         FIG. 5  is a schematic diagram of the maintenance pump at the time of the end of suction driving. 
         FIG. 6  is a schematic diagram of the maintenance pump at the time of the start of the suction driving. 
         FIG. 7  is a schematic diagram of a nozzle at the time of the suction driving of the maintenance pump. 
         FIG. 8  is a schematic diagram of the nozzle at the time of the discharge driving of the maintenance pump. 
         FIG. 9  is a schematic diagram of the nozzle after the end of cleaning. 
         FIG. 10  is a schematic diagram of an ink supply system of a second embodiment. 
         FIG. 11  is a sectional schematic diagram as viewed in the direction of the arrow XI-XI of  FIG. 10 . 
         FIG. 12  is a schematic diagram of a maintenance pump of the second embodiment. 
         FIG. 13  is a block diagram of a control section. 
         FIG. 14  is a sectional schematic diagram as viewed in the direction of the arrow XIV-XIV of  FIG. 11 . 
         FIG. 15  is a sectional schematic diagram of a recording head of a comparative example. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, embodiments that embody a liquid ejecting apparatus according to the invention in an ink jet type printer will be described on the basis of the drawings. A “right-and-left direction” and an “up-and-down direction”, as mentioned in the following explanation, are respectively set to represent a right-and-left direction and an up-and-down direction, that are indicated by arrows in  FIG. 1 . A “front-and-back direction”, as mentioned herein, is set to represent a direction perpendicular to the plane of paper of  FIG. 1 . 
     As shown in  FIG. 1 , an ink jet type printer (hereinafter also referred to as a “printer”)  11  as the liquid ejecting apparatus includes a transport unit  13  for transporting paper  12  as a target and a recording head unit  15  for carrying out printing on the paper  12 . 
     The transport unit  13  includes a rectangular plate-like platen  17  which is long in the right-and-left direction. While a driving roller  18  extending the front-and-back direction is disposed at the right side of the platen  17  so as to be able to be rotationally driven by a driving motor  19 , a driven roller  20  extending the front-and-back direction is rotatably disposed at the left side of the platen  17 . Further, a tension roller  21  extending the front-and-back direction is rotatably disposed below the platen  17 . 
     An endless transport belt  22  having a plurality of through-holes is wound around the driving roller  18 , the driven roller  20 , and the tension roller  21  so as to surround the platen  17 . In this case, the tension roller  21  is biased downward by a spring member (not shown) and provides tension to the transport belt  22 , thereby suppressing slack of the transport belt  22 . 
     By rotationally driving the driving roller  18  in the clockwise direction as viewed from the front side, the transport belt  22  is moved to circle outside the driving roller  18 , the tension roller  21 , and the driven roller  20  in the clockwise direction as viewed from the front side. The paper  12  is suctioned to the platen  17  side across the transport belt  22  by a suction section (not shown) in a case where the paper  12  is located at a position facing the upper face of the platen  17 , and is transported from the left side that is the upstream side toward the right side that is the downstream side. 
     A pair of upper and lower paper feed rollers  23  for sequentially feeding one by one a plurality of unprinted paper  12  onto the transport belt  22  is provided at the diagonally left upper side of the driven roller  20 . On the other hand, a pair of upper and lower paper discharge rollers  24  for discharging one by one the printed paper  12  from above the transport belt  22  is provided at the diagonally right upper side of the driving roller  18 . 
     As shown in  FIGS. 1 and 2 , at the recording head unit  15 , recording heads  26  to  29  as a plurality of pieces (in this embodiment, four pieces) of liquid ejecting heads each extending in the front-and-back direction are provided at intervals in the right-and-left direction. In nozzle formation faces  26   a  to  29   a , each of which becomes the lower face of each of the recording heads  26  to  29 , a number of nozzles  30  are regularly opened at given intervals in the front-and-back direction so as to form rows of nozzles along the front-and-back direction. To each nozzle  30  constituted in this manner, the same type of ink (liquid) is supplied for each of the recording heads  26  to  29  and then ejected from the nozzle  30 . 
     As shown in  FIG. 2 , an ink supply device  33  which supplies black ink from an ink cartridge  31  as a liquid supply source, in which the black ink is contained, through an ink flow path  32  as a liquid supply flow path is connected to the first recording head  26 . Similarly, the ink supply device  33  which supplies ink from each of the ink cartridges  31 , in which ink of the respective colors of cyan, magenta, and yellow is contained, is connected to each of the second to fourth recording heads  27  to  29 . 
     However, since the configurations of the respective ink supply devices  33 , each of which supplies ink from each ink cartridge  31  to each of the recording heads  26  to  29 , are the same as each other, in  FIG. 2 , only one ink supply device  33  which supplies ink to the first recording head  26  is shown along with the first recording head  26  and the ink cartridge  31 . In the following description, the first recording head  26  and the ink supply device  33  supplying ink to the first recording head  26 , which are shown in  FIG. 2 , are explained as an example. 
     As shown in  FIGS. 2 and 3 , in the first recording head  26 , a reservoir  36  which communicates with the downstream side of the ink flow path  32  is formed so as to extend in the front-and-back direction along the row of nozzles and also a plurality of branched flow paths  35  individually corresponding to the respective nozzles  30  from plural positions in the extending direction of the reservoir  36  is formed in a divergent fashion. Downstream end positions in the reservoir  36 , which become the branching points of the branched flow paths  35 , are set to be a branching position PB. 
     Each branched flow path  35  is constituted by a cavity  37  which communicates with the nozzle  30 , and a communicating flow path  38  which communicates with the cavity  37  and the reservoir  36 . In a direction (a direction perpendicular to the plane of paper in  FIG. 3 ) perpendicular to a direction in which ink flows, a cross-section area of the communicating flow path  38  is set to be small compared to a cross-section area of a flow path of the cavity  37 . 
     Further, as shown in  FIG. 3 , at a position adjacent to the cavity  37 , a piezoelectric element  40  is disposed through a vibration plate  39  which forms one wall face of the cavity  37 . By vibrating the vibration plate  39  by contracting and extending the piezoelectric element  40 , the volume of the cavity  37  is changed, whereby ink is ejected from the nozzle  30 . If ink in the cavity  37  is reduced in accordance with ejection, ink is supplied from the ink cartridge  31  side through the communicating flow path  38 , the reservoir  36 , and the ink flow path  32 . Therefore, the branched flow path  35 , the reservoir  36 , and the ink flow path  32  serve as a liquid supply flow path capable of supplying ink from the upstream side which is the ink cartridge  31  side to the downstream side which is the nozzle  30  side. 
     The nozzle  30  is constituted by a tapered portion  42 , in which a cross-section area is gradually reduced from the upstream side connected to the cavity  37  toward the downstream side, and an opening portion  43  which communicates with the tapered portion  42  and also is opened at the nozzle formation face  26   a . If ink is filled in the nozzle  30  from the upstream side, a meniscus M is formed in the nozzle  30  and in the vicinity of a nozzle orifice  44  opened at the nozzle formation face  26   a . The meniscus M is a curved surface in which the central portion of ink can rise due to capillarity so as to form a concave face shape as viewed from the nozzle orifice  44 . 
     As shown in  FIG. 2 , in the ink cartridge  31 , an ink pack  46  containing ink and having flexibility is housed in a case  47 . A pressurizing pump  49  is connected to the case  47  through an air flow path  48  and also the upstream end of the ink flow path  32  is connected to the ink pack  46 . Therefore, if the pressurizing pump  49  supplies air into the case  47  through the air flow path  48 , the ink pack  46  is crushed, so that ink in the ink pack  46  is supplied to the ink flow path  32 . 
     In the ink flow path  32 , at a pressure-adjusting position PT as a second position, a one-way valve  51  is provided which allows passage of ink from the upstream side to the downstream side in accordance with decompression on the downstream side, thereby adjusting pressure in the ink flow path  32 . The one-way valve  51  includes a storage chamber  52  which primarily stores ink pressurized and supplied from the ink cartridge  31 , and a pressure chamber  53  which is located further on the downstream side than the storage chamber  52 . The storage chamber  52  and the pressure chamber  53  are separated by a partition wall portion  54  and communicate with each other by the movement in a valve opening direction of a valve body  56 , which is biased in a valve closing direction by a spring  55 , thereby coming into contact with the partition wall portion  54 . 
     For this reason, if ink is ejected from the nozzle  30 , thereby being consumed, the inside of the pressure chamber  53  is decompressed, so that a film  57  is bent and deformed to the pressure chamber  53  side on the basis of the differential pressure between the pressure chamber  53  and the atmosphere. If the bending force becomes larger than the biasing force of the spring  55 , the valve body  56  moves to a valve opening position, in which the valve body  56  is separated from the partition wall portion  54 , so that the pressurized ink in the storage chamber  52  flows to the pressure chamber  53  side. If ink flows into the pressure chamber  53 , whereby the chamber pressure thereof is increased, the biasing force of the spring  55  overcomes, whereby the valve body  56  moves to a valve closing position in which the valve body  56  comes into contact with the partition wall portion  54  again. 
     In this manner, the one-way valve  51  is opened by decompression further on the downstream side than the valve body  56 , whereas, in a case where the upstream side is pressurized, the valve body  56  is forced in a closing direction, so that a valve closing state is maintained without valve opening. Also in a case where the downstream side is pressurized, similarly, since the film  57  is bent and deformed in a direction increasing the volume of the pressure chamber  53 , the valve body  56  maintains a valve closing state without receiving a force in a valve opening direction from the film  57 . Further, since ink on the upstream side remains pressurized by the pressurizing pump  49 , the upstream side further than the valve body  56  is not decompressed. The one-way valve  51  is a valve which is opened only when the downstream side is decompressed. 
     A portion of the pressure chamber  53  is constituted by the film  57  made of a flexible material (for example, synthetic resin, rubber, or the like) and for example, a cantilevered metal fragment (for example, a piece of a metal fragment of a comb-tooth shape) (not shown) capable of being deformed along with the film  57  is disposed at a contact place of the valve body  56 . 
     A maintenance pump  61  as a pump which changes pressure in the ink flow path  32 , thereby allowing ink to be suctioned and discharged, is connected to a pressure-changing position PH as a first position which is further on the downstream side than the pressure-adjusting position PT. 
     The maintenance pump  61  is a pump capable of pressurizing ink in the recording head  26 . The pressurizing pump  49  is provided separately from the maintenance pump  61 . However, pressurization by the pressurizing pump  49  is blocked by the one-way valve  51 , so that the pressurizing force cannot be transmitted to the recording head  26 . Accordingly, in order to perform maintenance of the recording head  26 , the maintenance pump  61  capable of pressurizing ink in the recording head  26  is required separately from the pressurizing pump  49 . 
     As shown in  FIG. 4 , the maintenance pump  61  includes a tube  62  having flexibility, a frame body  63  supporting the tube  62 , and a pressing mechanism  64  capable of pressing the tube  62 . A base end portion  62   a  of the tube  62  is connected to the ink flow path  32 , whereas a leading end portion  62   b  of the tube  62  is blocked. 
     The frame body  63  has a base end support portion  63   a , a leading end support portion  63   b , and an intermediate support portion  63   c , which respectively support the base end portion  62   a , the leading end portion  62   b , and an intermediate portion  62   c  of the tube  62 . The base end support portion  63   a  and the leading end support portion  63   b  of the frame body  63  are formed into a tubular shape so as to support the base end portion  62   a  and the leading end portion  62   b  of the tube  62  in a state where the end portions are inserted therein. The intermediate support portion  63   c  of the frame body  63  is a plate-like body connecting the base end support portion  63   a  and the leading end support portion  63   b  and is formed to be curved in a circular arc shape in a cross section so as to support the intermediate portion  62   c  of the tube  62  from the outer circumference side thereof in a state where the intermediate portion  62   c  is curved in a circular arc shape. 
     The pressing mechanism  64  is disposed at a position on the inner side (inner circumference side) of the intermediate portion  62   c  of the tube  62  supported by the intermediate support portion  63   c  of the frame body  63  in a state where the intermediate portion  62   c  is curved in a circular arc shape. The pressing mechanism  64  includes a rotating plate  66  rotatable around a driving shaft  65 , and a pressing roller  67  rotatably provided at a leading end portion of a tongue portion  66   a  protruding outward in the radial direction of the rotating plate  66 . The pressing roller  67  is disposed to be capable of clamping the tube  62  so as to crush the tube  62  in cooperation with the intermediate support portion  63   c  by pressing the intermediate portion  62   c  of the tube  62  from the inner circumference side toward the intermediate support portion  63   c  side of the frame body  63 . 
     For this reason, the inside of the tube  62  (specifically, the intermediate portion  62   c ) is sectioned into an ink chamber  69  as a liquid chamber which is on the base end portion  62   a  side, and a gas chamber  70  which is on the leading end portion  62   b  side, with a pressing point  62   d  crushed by the pressing roller  67  and the intermediate support portion  63   c  of the frame body  63  as a boundary. The ink chamber  69  communicates with the ink flow path  32 , thereby being filled with ink. On the other hand, in the gas chamber  70 , gas (for example, air) is contained. 
     If the driving shaft  65  rotates in accordance with the driving of a pressing motor  68  (refer to  FIG. 2 ), the pressing roller  67  rotates along with the rotating plate  66  in a direction (the clockwise direction) indicated by a white arrow in  FIG. 4 . If the pressing roller  67  rotationally moves in a state where it has crushed the tube  62 , the pressing point  62   d  moves in a direction in which the volume of the ink chamber  69  is increased and also the volume of the gas chamber  70  is reduced. Therefore, the pressing roller  67  serves as a volume changing section which changes the volumes of the ink chamber  69  and the gas chamber  70 . 
     Specifically, when the pressing roller  67  which is located at a standby position P 1 , as shown in  FIG. 4 , rotationally moves up to a suction ending position P 2  shown in  FIG. 5 , the volume of the ink chamber  69  is increased, so that ink is suctioned from the inside of the ink flow path  32 . On the other hand, the volume of the gas chamber  70  is reduced, so that the contained gas is compressed. 
     For this reason, if the pressing roller  67  rotationally moves additionally from the suction ending position P 2 , thereby being located at a non-clamping area A, a clamped state of the tube  62  is released, so that the pressure of the compressed air contained in the gas chamber  70  acts on ink in the ink chamber  69 . For this reason, the ink is pushed by the gas, thereby moving to the base end portion  62   a  side and then being discharged into the ink flow path  32 . The non-clamping area A is at a position where the pressing roller  67  does not face the intermediate support portion  63   c  through the tube  62 . 
     If the pressing roller  67  rotationally moves additionally, thereby moving up to a clamping area B where the pressing roller  67  can clamp the tube  62  along with the intermediate support portion  63   c , as shown in  FIG. 6 , the pressing roller  67  presses the tube  62  against the intermediate support portion  63   c , thereby clamping the tube  62 . The clamping area B is at a position where the pressing roller  67  faces the intermediate support portion  63   c  through the tube  62  and presses the tube  62  against the intermediate support portion  63   c , thereby being capable of clamping the tube  62 . The pressing roller  67  rotationally moves additionally from a suction starting position P 3  shown in  FIG. 6 , whereby ink in the ink flow path  32  is suctioned into the ink chamber  69 . 
     Therefore, the maintenance pump  61  performs discharge driving and suction driving by the rotational driving of the driving shaft  65  by the pressing motor  68 . In this embodiment, the thickness and the length of the tube  62  are set such that the volume of the tube  62  between the suction starting position P 3  and the standby position P 1  becomes equal to or greater than the amount of change in volume of the pressure chamber  53  accompanying the displacement of the film  57 . 
     Further, as shown in  FIG. 2 , at the printer  11 , a control section  72  as a control unit which performs overall control of the operation status of the printer  11  is provided. The control section  72  controls the driving of the piezoelectric element  40  provided at each of the recording heads  26  to  29 , the pressuring pump  49 , and the pressing motor  68 , thereby performing printing and cleaning processes. 
     Next, an action in the printer  11  constituted as described above will be described below. 
     Now, if printing is started in the printer  11 , the control section  72  creates ejection timing for each nozzle  30  on the basis of printing data and also drives the piezoelectric element  40  on the basis of the ejection timing. Then, the vibration plate  39  is displaced in a direction reducing the volume of the cavity  37 , thereby ejecting ink from the nozzle  30 . Ink ejected from each nozzle  30  adheres to the paper  12  which is supported on and transported by the transport belt  22 , whereby printing is carried out on the paper  12 . 
     If ink is consumed by ejection from the nozzle  30 , decompression accompanying a reduction in ink is transmitted to the one-way valve  51  through the reservoir  36  and the ink flow path  32 . Then, the valve body  56  moves to a valve opening position against the biasing force of the spring  55 , so that ink in the storage chamber  52  flows to the pressure chamber  53  side. If ink flows into the pressure chamber  53 , whereby the chamber pressure thereof is increased, the biasing force of the spring  55  overcomes, whereby the valve body  56  moves to a valve closing position again. 
     Therefore, since the one-way valve  51  is made so as to allow passage of ink from the upstream side to the downstream side in accordance with decompression on the downstream side, ink corresponding to the consumed amount is supplied from the ink cartridge side. Therefore, even if ink is ejected from the nozzle in accordance with printing, the position of the meniscus M is located in the vicinity of the nozzle orifice  44 , as shown in  FIG. 3 . 
     Incidentally, if a period in which printing is not carried out, so that ink is not ejected from the nozzle, becomes longer, sometimes, ink evaporates from the nozzle orifice  44 , whereby ink is thickened or the position of the meniscus M rises. The rising of the position of the meniscus M sometimes occurs also in other situations such as a case where the printer  11  is subjected to a shock or a case where an end of the paper  12  comes into contact with the nozzle orifice  44 , as well as the time of evaporation of ink. 
     Therefore, the control section  72  carries out a cleaning process, for example, in a case where a cleaning process execution command from a user is received from an operation section (not shown) or a case where a decision is made that a predetermined time has passed from a cleaning process of the previous time. At the time of printing or standby, which become the time of a non-cleaning process, the pressing roller  67  of the maintenance pump  61  is set to be located at the standby position P 1  in the clamping area B. 
     The control section  72  drives the pressing motor  68 , thereby rotating the pressing roller  67  by one revolution around the driving shaft  65 . The pressing roller  67  which is located at the standby position P 1  moves to the suction ending position P 2  side and then passes through the non-clamping area A and the suction starting position P 3 , thereby returning to the standby position P 1 . 
     During movement from the standby position P 1  up to the suction ending position P 2 , since the volume of the ink chamber  69  is increased, the maintenance pump  61  performs suction driving, thereby suctioning ink from the ink flow path  32  (the first suctioning). 
     If the maintenance pump  61  performs the suction driving, further at the downstream side than the pressure-changing position PH in the ink flow path  32 , ink is suctioned from the nozzle  30  side. Therefore, the meniscus M located in the vicinity of the nozzle orifice  44  rises in position, as shown in  FIG. 7 , and also, in the nozzle  30  in which the position of the meniscus M has risen originally, the position further rises. Negative pressure accompanying the suction driving of the maintenance pump  61  also acts further on the upstream side than the pressure-changing position PH. For this reason, the film  57  is displaced in a direction in which the volume of the pressure chamber  57  is reduced, thereby opening the one-way valve  51 , so that ink is also supplied from the ink cartridge  31  side. 
     Now, if the pressing roller  67  rotationally moves additionally from the suction ending position P 2 , thereby moving to the non-clamping area A, the maintenance pump  61  performs the discharge driving. The pressure of gas in the gas chamber  70  acts on ink in the ink chamber  69 , so that ink in the ink chamber  69  is discharged into the ink flow path  32  (discharging). 
     Incidentally, the one-way valve  51  provided further at the upstream side than the pressure-changing position PH in the ink flow path  32  is opened when it is decompressed from the downstream side, whereas the one-way valve  51  maintains a valve closing state when it is pressurized from the downstream side. For this reason, if ink is discharged from the maintenance pump  61 , since the one-way valve  51  remains closed, ink is supplied to the nozzle  30  side which is further on the downstream side than the pressure-adjusting position PT. Ink that the maintenance pump  61  discharges in accordance with the discharge driving is the sum of ink filled in the ink chamber  69  in a case where the pressing roller  67  is located at the standby position P 1  and ink suctioned in the first suctioning. Further, since ink is also suctioned from the ink cartridge  31  side at the time of the suction driving, the amount of ink which is supplied to the nozzle  30  side at the time of the discharge driving is larger than the amount of ink suctioned from the nozzle  30  side in the first suctioning. 
     Therefore, if the maintenance pump  61  performs the discharge driving, ink thickened in the vicinity of the nozzle orifice  44  or ink in which air bubbles are mixed therein is discharged along with ink supplied form the maintenance pump  61  side, so that cleaning of the recording head  26  is performed. Incidentally, if ink is discharged from the nozzle  30  in accordance with the cleaning, ink sometimes adheres to the nozzle formation face  26   a  in the vicinity of the nozzle orifice  44  (refer to  FIG. 8 ). 
     Further, at the time of the discharge driving of the maintenance pump  61 , the discharge pressure of the maintenance pump  61  acts on the pressure chamber  53 , so that the film  57  is bent and deformed to the atmospheric pressure side, thereby increasing the volume of the pressure chamber  53 . For this reason, in the pressure chamber  53 , in which the volume is increased, whereby a pressurizing force is accumulated, negative pressure cannot be applied to ink and further the accumulated pressurizing force is transmitted to the nozzle  30  side, so that there is also a possibility that discharge of ink from the nozzle  30  may be continued. 
     However, the pressing roller  67  passes through the non-clamping area A and also rotationally moves to the suction starting position P 3  which is further on the base end portion  62   a  side than the suction ending position P 2 , thereby crushing the tube  62 . Further, the control section  72  stops the driving of the pressing motor  68  at the timing when the pressing roller  67  is located at the standby position P 1 . During the movement of the pressing roller  67  from the suction starting position P 3  up to the standby position P 1 , since the volume of the ink chamber  69  is increased, the maintenance pump  61  performs the suction driving, thereby suctioning ink from the ink flow path  32  (the second suctioning). 
     Then, further at the downstream side than the pressure-changing position PH, since ink is suctioned from the nozzle  30  side, ink adhered to the vicinity of the nozzle orifice  44  is suctioned into the nozzle  30 . Further at the upstream side than the pressure-changing position PH, since ink in the pressure chamber  53  is suctioned, the film  57  is bent and deformed to the storage chamber  52  side, so that a pressurized state is released. Incidentally, in this embodiment, the volume of the tube  62  between the suction starting position P 3  and the standby position P 1  is set to be equal to or more than the amount of change in the volume of the pressure chamber  53  accompanying the displacement of the film  57 . For this reason, in a case where ink larger than the amount of change in the volume of the pressure chamber  53  is suctioned in accordance with the suction driving of the maintenance pump  61 , the one-way valve  51  is opened, whereby ink is supplied from the ink cartridge  31  side. Therefore, as shown in  FIG. 9 , the meniscus M is located in the vicinity of the nozzle orifice  44 . 
     According to the above-described embodiment, the following effects can be obtained. 
     (1) By the discharge driving of the maintenance pump  61 , the cleaning process can be performed in which ink is supplied to the nozzle  30  side through the ink flow path  32  and then discharged from the nozzle  30 . At this time, since the maintenance pump  61  discharges ink into the ink flow path  32  at the pressure-changing position PH, discharge pressure also acts on the pressure chamber  53  of the one-way valve  51  provided at the pressure-adjusting position PT. Then, while the one-way valve  51  maintains a closed state, the pressure chamber  53  expands, thereby accumulating a pressurizing force. However, since the maintenance pump  61  performs the suction driving after the discharge driving, it is possible to suppress transmission of the pressurizing force to the nozzle  30  side by suctioning ink in the ink flow path  32 , thereby contracting the pressure chamber  53 . Therefore, it is possible to perform the cleaning where the consumption of ink after the end of the cleaning is suppressed. 
     (2) In a case where the viscosity of ink has risen or a case where air bubbles have been mixed in ink, the fluidity of ink decreases. In that respect, it is possible to vigorously discharge ink into the ink flow path  32  by compressing gas in the gas chamber  70  and also providing the pressure of the compressed gas to ink in the ink chamber  69 . Since it is not necessary to provide an accumulating configuration of the pressurizing force of the maintenance pump  61 , such as a valve, at the ink flow path  32 , an increase in the number of parts is suppressed, so that it is possible to speed up the flow velocity of ink. 
     (3) Since it is possible to contract the pressure chamber  53  expanded in accordance with the discharge driving of the maintenance pump  61  so as to become a minimal volume by the suction driving of the maintenance pump  61 , it is possible to suppress transmission of the pressurizing force to the nozzle  30  side. In a case where the maintenance pump  61  has suctioned ink equal to or more than the amount of change of the pressure chamber  53 , since the inside of the pressure chamber  53  is decompressed, the one-way valve  51  is opened, so that ink is supplied from the upstream side into the pressure chamber  53 . For this reason, it is possible to suppress the consumption of ink after the cleaning and also adjust pressure further on the downstream side than the one-way valve  51  in the ink flow path  32 . 
     (4) Ink suctioned by the movement of the pressing roller  67  from the suction starting position P 3  up to the standby position P 1  at the time of the cleaning of the previous time can be used in cleaning. Since in the case of performing cleaning, it is not necessary to suction all the amount of ink required for the cleaning, it is possible to promptly perform the cleaning. 
     In addition, the above-described embodiment may be modified as follows. 
     In the above-described embodiment, a configuration is also acceptable in which the pressing roller  67  is located at the suction ending position P 2  at the time of non-cleaning and at the time of cleaning, the pressing roller  67  is rotated by one revolution around the driving shaft  65  from the suction ending position P 2 . The maintenance pump  61  may be made to wait in a state where the volume of the ink chamber  69  is increased and also a state where the volume of the gas chamber  70  is reduced, whereby gas is compressed. In this case, if the control section  72  drives the pressing motor  68 , the pressing roller  67  moves to the non-clamping area A, whereby the maintenance pump  61  performs the discharge driving. Subsequently, since the pressing roller  67  moves in the clamping area B in a state where it has crushed the tube  62 , the volume of the ink chamber  69  is gradually increased, so that ink is suctioned from the ink flow path  32 . The pressurizing force remaining in the ink flow path  32  can be recovered by performing the suction driving of the maintenance pump  61  after the discharge driving. 
     In the above-described embodiment, in the maintenance pump  61 , the volume of the tube  62  between the suction starting position P 3  and the suction ending position P 2  may be set so as to become equal to or more than the amount of change in volume accompanying the displacement of the film  57  of the pressure chamber  53 . At the time of the discharge driving before the maintenance pump  61  stops, it is preferable to suction ink to the extent capable of recovering the pressurizing force accumulated in the pressure chamber  53 . 
     In the above-described embodiment, the maintenance pump  61  may be a piston pump or a diaphragm pump which changes the volume of the ink chamber by the displacement of a diaphragm. The volumes of the ink chamber and the gas chamber may be changed in accordance with the movement of a piston or a diaphragm. The maintenance pump  61  may be constituted to be a gear pump or a vane pump, which has an ink containing chamber, and move ink from the ink flow path  32  to the ink containing chamber in the case of performing the suction driving and ink from the ink containing chamber to the ink flow path  32  in the case of performing the discharge driving. 
     In the above-described embodiment, the maintenance pump  61  may perform the suction driving and the discharge driving by reciprocating the pressing roller  67  with the clamping state of the tube  62  maintained by the pressing roller  67  and the intermediate support portion  63   c . The control section  72  controls the pressing motor  68  so as to reciprocate the pressing roller  67  in the clamping area B. Then, the maintenance pump  61  performs the suction driving in a case where the pressing roller  67  moves in the clockwise direction in  FIG. 4  from the suction starting position P 3  to the suction ending position P 2  and performs the discharge driving in a case where the pressing roller  67  moves in the counterclockwise direction from the suction ending position P 2  to the suction starting position P 3 . In a case where the pressing roller  67  reciprocates in the clamping area B, a configuration is also acceptable in which the leading end portion  62   b  of the tube  62  is opened, so that the gas chamber  70  is not provided. 
     In the above-described embodiment, the frame body  63  may support the tube  62  in a linear fashion, and if the pressing point  62   d  can be changed in a state where the tube  62  is crushed, the clamping section can be arbitrarily changed. For example, the tube  62  may be clamped by a pair of pressing rollers. 
     In the above-described embodiment, the cleaning process may be performed by rotating more than once the pressing roller  67  around the driving shaft  65 . For example, in a case where the degree of the thickening of ink or the degree of the rising of the position of the meniscus M is high, there is a fear that restoration does not occur in single discharge driving of the maintenance pump  61 . In that respect, it is possible to restore the state of the nozzle  30  by carrying out the discharge driving more than once. Even in a case where the maintenance pump  61  is driven more than once, by performing the suction driving between the discharge driving processes, it is possible to suppress the overflowing of ink from the nozzle  30  at the time of the suction driving. By stopping the pressing roller  67  at the standby position P 1 , it is possible to suppress the overflowing of ink from the nozzle  30  even after the end of the cleaning, because it is possible to stop the maintenance pump  61  after the suction driving. 
     In the above-described embodiment, the maintenance pump  61  may be connected to the reservoir  36  to suction and discharge ink in the reservoir  36 . The pressure-changing position PH where the maintenance pump  61  is connected may be arbitrarily set between the pressure-adjusting position PT and the branching position PB. 
     Second Embodiment 
       FIG. 10  shows a schematic diagram of an ink supply system related to a second embodiment. At a position in the vicinity of each of the recording heads  26  to  29 , a wiper  34  (refer to  FIG. 14 ) capable of coming into contact with each of the nozzle formation faces  26   a  to  29   a , and a wiping mechanism  35  (refer to  FIG. 13 ) which moves the wiper  34  along each of the nozzle formation faces  26   a  to  29   a  are provided. The wiping mechanism  35  performs wiping which sweeps each of the nozzle formation faces  26   a  to  29   a  by the wiper  34  by moving the wiper  34  in a state where the wiper  34  has come into contact with each of the nozzle formation faces  26   a  to  29   a . Therefore, the wiping mechanism  35  functions as a wiping section. 
     As shown in  FIGS. 10 and 11 , in the first recording head  26 , the reservoir  36  as a liquid supply chamber is formed so as to extend in the front-and-back direction along the row of nozzles, similarly to the first embodiment. In the reservoir  36 , at least one connection port  36   a  is formed for each of a plurality of areas (in this embodiment, three areas A to C) sectioned at least in the longitudinal direction (the front-and-back direction) of the reservoir  36 . A plurality of downstream ends  32   b  of the ink flow path  32  branched at a branching portion  32   a  is respectively connected to each connection port  36   a.    
     It is preferable that the reservoir  36  be sectioned into the same number (in this embodiment, three) of areas A to C as the number of the downstream ends  32   b  of the ink flow path  32  which is connected thereto and further that the respective areas A to C have equal intervals in the front-and-back direction. For example, in a case where the shape of the reservoir  36  is line-symmetrical or point-symmetrical in the front-and-back direction, it is preferable that the areas A to C be sectioned so as to become line-symmetrical or point-symmetrical. It is preferable that the connection ports  36   a  be also formed so as to become line-symmetrical or point-symmetrical. In a case where a plurality of connection ports  36   a  is formed in one area, it is preferable to form the same number of connection ports  36   a  in the respective areas A to C. 
     As shown in  FIG. 10 , an upstream end  32   c  of the ink flow path  32  is connected to the ink pack  46 . For this reason, if the pressurizing pump  49  supplies air into the case  47  through the air flow path  48 , the ink pack  46  is crushed, so that ink in the ink pack  46  is supplied to the ink flow path  32 . 
     In the ink flow path  32 , at a opening and closing position PK which is further on the downstream side than the pressure-adjusting position PT where the one-way valve  51  is provided, a flow path valve  60  capable of opening and closing the ink flow path  32  is provided. Further, a maintenance pump  161  as a pump which changes pressure in the ink flow path  32 , thereby being capable of suctioning and discharging ink, is connected to the pressure-changing position PH as a connection position which is further on the downstream side than the opening and closing position PK and further on the upstream side than the branching portion  32   a  of the ink flow path  32 . 
     As shown in  FIG. 12 , the maintenance pump  161  includes a tube  162  having flexibility, and a pair of pressing rollers  163  and  164 . A base end portion  162   a  of the tube  162  is connected to the ink flow path  32 , whereas a leading end portion  162   b  of the tube  162  is opened. The pair of pressing rollers  163  and  164  is disposed in a state where they clamp the tube  162  so as to crush the tube  162  from both sides. The maintenance pump  161  is provided with a movement mechanism  165  (refer to  FIG. 13 ) which reciprocates the pressing rollers  163  and  164  between a discharge position shown by a solid line in  FIG. 12  and a suction position shown by a two-dotted and dashed line. 
     By the movement of the pressing rollers  163  and  164 , which are located at the discharge position that is on the base end portion  162   a  side of the tube  162 , to the suction position side that is further on the leading end portion  162   b  side than the discharge position, ink in the ink flow path  32  is suctioned into the tube  162 . By the movement of the pressing rollers  163  and  164  which are located at the suction position to the discharge position side, ink in the tube  162  is pushed by the pressing rollers  163  and  164 , thereby being discharged to the ink flow path  32 . Therefore, the maintenance pump  161  performs the suction driving and the discharge driving by the movement of the pressing rollers  163  and  164  by the movement mechanism  165 . 
     Further, as shown in  FIG. 13 , at the printer  11 , a control section  167  as a control unit which performs overall control of the operation status of the printer  11  is provided. The control section  167  controls the driving of the wiping mechanism  35 , the piezoelectric element  40 , the pressurizing pump  49 , the flow path valve  60 , and the movement mechanism  165  in accordance with an input from an operation section  168  by a user, thereby performing printing and wiping processes. 
     Next, an action in the printer  11  constituted as described above will be described below. 
     Now, if printing is started in the printer  11 , the control section  167  creates ink ejection timing for each nozzle  30  on the basis of printing data and also drives the piezoelectric element  40  on the basis of the ejection timing. Then, the vibration plate  39  is displaced in a direction reducing the volume of the cavity  37 , thereby ejecting ink from the nozzle  30 . Ink ejected from each nozzle  30  adheres to the paper  12  which is supported on and transported by the transport belt  22 , whereby printing is carried out on the paper  12 . 
     The flow path valve  60  maintains a valve opening state at the time of printing. For this reason, if ink is ejected from the nozzle  30 , thereby being consumed, decompression accompanying a reduction in ink is transmitted to the one-way valve  51  through the reservoir  36  and the ink flow path  32 , so that the film  57  is bent and deformed to the pressure chamber  53  side on the basis of a differential pressure between the pressure chamber  53  and the atmosphere. Then, the valve body  56  moves to a valve opening position against the biasing force of the spring  55 , so that ink in the storage chamber  52  flows to the pressure chamber  53  side. If ink flows into the pressure chamber  53 , whereby the chamber pressure thereof is increased, the biasing force of the spring  55  overcomes, whereby the valve body  56  moves to a valve closing position again. 
     Therefore, since the one-way valve  51  is made so as to allow passage of ink from the upstream side to the downstream side in accordance with decompression on the downstream side, ink corresponding to the consumed amount is supplied from the ink cartridge side. Therefore, even if ink is ejected from the nozzle  30  in accordance with printing, the position of the meniscus M is located in the vicinity of the nozzle orifice  44 , as shown in  FIG. 11 . 
     Incidentally, if printing is performed by transporting the paper  12  and also ejecting ink from the nozzle  30 , ink mist or paper dust scattered in accordance with the ejection of ink adheres to the nozzle formation face  26   a.    
     For this reason, the control section  167  carries out a wiping process in a case where a wiping process execution command from a user is received from the operation section  168  or a case where a decision is made that the sweeping of the nozzle formation face  26   a  is required just after the cleaning process of discharging ink from the nozzle  30 , or the like. At the time of printing or standby, which becomes the time of a non-wiping process, a setting is made such that the pressing rollers  163  and  164  of the maintenance pump  161  are located at the discharge position and also the flow path valve  60  is opened. 
     Now, in the case of carrying out the wiping process, first, the control section  167  closes the flow path valve  60  and also drives the movement mechanism  165 , thereby moving the pressing rollers  163  and  164  to the suction position side. For this reason, the maintenance pump  161  performs suction driving, thereby suctioning ink further from the downstream side than the flow path valve  60  (suctioning). 
     Then, the position of the meniscus M which has been located in the vicinity of the nozzle orifice  44  rises as shown in  FIG. 14 . In this embodiment, suction power is provided to plural positions in the reservoir  36  through the ink flow path  32  branched at the branching portion  32   a . For this reason, since ink is suctioned in a state where variation in the suction power that is provided to the nozzle  30  is suppressed, the meniscus M of each nozzle  30  rises in a state where the variation is suppressed. 
     In a state where the meniscus M has risen, the control section  167  controls the driving of the wiping mechanism  35 , thereby moving the wiper  34  in a direction indicated by an arrow in  FIG. 14  in a state where the wiper  34  is brought into contact with the nozzle formation face  26   a  (wiping). Then, the nozzle formation face  26   a  is swept by the wiper  34 . 
     Thereafter, the control section  167  controls the movement mechanism  165  such that the maintenance pump  161  performs discharge driving, and pushes out ink in the tube  162  suctioned from the inside of the ink flow path  32  in accordance with the previous suction driving, from the inside of the tube  162 , thereby discharging the ink to the ink flow path  32  (discharging). However, since the flow path valve  60  further on the upstream side than the pressure-changing position PH, to which the maintenance pump  161  is connected, in the ink flow path  32  has been closed, the discharged ink is supplied to the downstream side. Therefore, the meniscus M which has risen in accordance with the suction driving of the maintenance pump  161  lowers in position, thereby moving to the vicinity of the nozzle orifice  44 . 
       FIG. 15  shows the positions of the meniscuses M in a case where an ink flow path, in which a downstream end is not branched, is connected to the central portion of the reservoir  36  and suction power is provided to one place in the reservoir  36 , as a comparative example. To the nozzle  30  of the central portion close to a connection port, suction power large compared to that to the nozzles  30  of both end portions distant from the connection port is provided. For this reason, in the nozzle  30  of the central portion, the position of the meniscus M rises, whereas in the nozzles  30  of both end portions, the meniscus M does not rise, whereby variation occurs in the positions of the meniscuses M. 
     For this reason, if the wiper  34  moves in a state where it has come into contact with the nozzle formation face  26   a , there is a fear that ink in the nozzle  30  may come into contact with the wiper  34 , whereby the ink flows down the wiper  34  to the outside of the nozzle  30 . 
     Further, in a case where the maintenance pump  161  performs the discharge driving, since a pressurizing force is also applied to the nozzle  30  in which the meniscus M is located in the vicinity of the nozzle orifice  44 , there is a fear that ink may overflow from the nozzle  30 . 
     Therefore, it is preferable to provide the suction power in a state where the ink flow path  32  is connected to plural positions of the reservoir  36  in such a manner that a difference of the distance between the respective nozzles  30  becomes small. 
     According to the above-described embodiment, the following effects can be obtained. 
     (5) For example, in a case where ink is suctioned by a single ink flow path  32  which is not branched, a difference in suction power which is transmitted to the respective nozzles  30  becomes large, so that variation occurs in the positions of the meniscuses M. In that respect, since the ink flow path  32  is branched and connected to the reservoir  36 , it is possible to transmit suction power to plural locations in the reservoir  36 . Since it is possible to sweep the nozzle formation face  26   a  by the wiper  34  in a state where the meniscuses M have risen in the respective nozzles  30 , it is possible to suppress the consumption of ink accompanying the contact of the wiper  34  with ink. Since the positions of the meniscuses M move up in a state where variation in position is reduced, it is possible to suppress the overflowing of ink from the nozzle  30  at the time of the discharge driving of the maintenance pump  161 . Therefore, it is possible to perform wiping where the outflow of ink from the nozzle  30  is suppressed. 
     (6) Since at least one connection port  36   a  is formed for each of a plurality of areas in the reservoir  36 , a possibility that the downstream ends  32   b  of the ink flow path  32  may be disproportionately connected to the reservoir  36  is reduced. Therefore, the bias of suction power which is exerted to the inside of the reservoir  36  when the maintenance pump  161  performs the suction driving is suppressed, so that variation in the positions of the meniscuses M can be further reduced. 
     (7) It is possible to transmit pressure to the reservoir  36  through the branched ink flow path  32  by driving a single maintenance pump  161 . Therefore, compared to a case where the maintenance pump  161  is provided at each ink flow path  32  which is further on the downstream side than the branching portion  32   a , the number of parts is reduced, so that a reduction in size of the printer  11  can be attained. 
     (8) By performing the suction driving of the maintenance pump  161  in a state where the flow path valve  60  has been closed, it is possible to suppress the inflow of ink from the upstream side and suction ink from the downstream side. Therefore, the amount of ink which is supplied to the downstream side when the maintenance pump  161  performs the discharge driving becomes approximately equal to the amount of ink suctioned in accordance with the suction driving. For this reason, it is possible to reduce a possibility that ink may overflow from the nozzle  30 , and also to reduce a possibility that the nozzle formation face  26   a  after wiping may be contaminated with ink overflowed from the nozzle  30 . 
     In addition, the above-described embodiment may be modified as follows. 
     In the above-described embodiment, the maintenance pump  161  may be a piston pump or a diaphragm pump which changes the volume of a pump chamber by the displacement of a diaphragm. The maintenance pump may be constituted to be a gear pump or a vane pump, which has an ink containing chamber, and move ink from the ink flow path  32  to the ink containing chamber in the case of performing the suction driving and ink from the ink containing chamber to the ink flow path  32  in the case of performing the discharge driving. In a case where the gear pump or the vane pump is adopted as the maintenance pump  161 , it is also acceptable to adopt a configuration in which the one-way valve  51  and the flow path valve  60  are not provided and ink is suctioned from the nozzle  30  side by supplying ink from the downstream side to the upstream side. 
     In the above-described embodiment, the flow path valve  60  may be provided at a position which is further on the upstream side than the pressure-adjusting position PT where the one-way valve  51  is provided, in the ink flow path  32 . By performing the suction driving of the maintenance pump  161  in a state where the flow path valve  60  which is located further at the upstream side than the one-way valve  51  has been closed, ink further from the upstream side than the flow path valve  60  is not supplied even if the one-way valve  51  is opened, and ink is suctioned from the nozzle  30  side. On the other hand, in a case where the maintenance pump  161  performs the discharge driving, since the one-way valve  51  is closed, ink is supplied to the nozzle  30  side. Therefore, since ink suctioned from the nozzle  30  side can be supplied to the nozzle  30  side, it is possible to suppress the discharging of ink from the nozzle  30 . 
     In the above-described embodiment, a plurality of maintenance pumps  161  and flow path valves  60  may be respectively provided at each ink flow path  32  further on the downstream side than the branching portion  32   a . The respective branched ink flow paths  32  communicate with each other. For this reason, it is also acceptable to provide the maintenance pump  61  at a single ink flow path  32  which is branched at the branching portion  32   a  and is further on the downstream side than the branching portion  32   a , and also provide the flow path valve  60  at the ink flow path  32  further on the upstream side than the branching portion  32   a.    
     In the above-described embodiment, it is preferable if at least two connection ports  36   a  are formed in the reservoir  36  and the branched ink flow path  32  is connected to the connection ports  36   a . Even in a case where a plurality of connection ports  36   a  is closely formed, it is possible to suppress the bias of suction power which is transmitted to the nozzles  30 , compared to a case where ink is suctioned from a single connection port  36   a.    
     In the above-described embodiments, the liquid ejecting apparatus is embodied in the ink jet type printer  11 . However, a liquid ejecting apparatus that ejects or discharges liquid other than ink may be adopted. The invention can be applied to various liquid ejecting apparatuses that are each provided with a liquid ejecting head or the like that discharge a minutely small amount of liquid droplet. In addition, the liquid droplet describes a liquid in a state of being discharged from the liquid ejecting apparatus and also includes droplets of a granular shape or a tear shape, or droplets tailing into a line. It is acceptable if the liquid as mentioned herein is a material that can be ejected by a liquid ejecting apparatus. For example, it is acceptable if the liquid is a substance in a liquid state, and the liquid includes not only liquids in a liquid state with high or low viscosity, a flow state such as sol, gel water, other inorganic or organic solvents, solution, liquid resin, or liquid metal (metal melt), and one state of substance, but also a material in which particles of a functional material composed of a solid material such as pigment or metal particles are dissolved, dispersed, or mixed in a solvent, or the like. Also, ink as described in the above-described embodiments, a liquid crystal, or the like can be given as representative examples of the liquid. Here, ink is set to include general water-based ink and oil-based ink and various liquid compositions such as gel ink, hot-melt ink, and the like. As specific examples of the liquid ejecting apparatus, the following can be given: a liquid ejecting apparatus that ejects liquids that include, in a dispersed or dissolved form, materials such as an electrode material or a color material, which is used for the manufacturing or the like of, for example, a liquid crystal display, an EL (electroluminescence) display, a surface-emitting display, or a color filter; a liquid ejecting apparatus that ejects a biological organic matter that is used for the manufacturing of biochips; a liquid ejecting apparatus that is used as a precision pipette and ejects liquid that is a sample; a textile printing apparatus; a micro-dispenser; and the like. Further, the following liquid ejecting apparatuses may be adopted: a liquid ejecting apparatus that ejects lubricant oil to a precision machine such as a clock or a camera by using a pinpoint; a liquid ejecting apparatus that ejects a transparent resin solution such as ultraviolet curing resin onto a substrate in order to form a minute hemispherical lens (an optical lens) or the like which is used in an optical communication element or the like; and a liquid ejecting apparatus that ejects an etching solution such as acid or alkali in order to etch a substrate or the like. The invention can be applied to any one type of liquid ejecting apparatus among these. 
     The entire disclosure of Japanese Patent Application Nos. 2010-025281, filed Feb. 8, 2010, 2010-025280, filed Feb. 8, 2010 are expressly incorporated by reference herein.