Abstract:
A liquid ejecting apparatus including a main tank configured to agitate a liquid accommodated in the main tank; a sub tank configured to receive the liquid supplied from the main tank; heads that eject the liquid supplied from the sub tank; and a liquid supply tube having connector tubes that branch off to the heads respectively; a pump that sucks liquid from the main tank and discharges such liquid to the sub tank; and a valve separated from the pump that operates to allow or restrict flow of the liquid between the main tank and the sub tank. The main ink tank may include a drawer assembly, a portion of which is manually movable to agitate the liquid. The main tank may have a capacity that is greater than that of the sub tank.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
     This application is a continuation of, and claims priority under 35 U.S.C. §120 on, application Ser. No. 14/056,273, filed Oct. 17, 2013, now U.S. Pat. No. 8,764,140, issued Jul. 1, 2014, which is a continuation of application Ser. No. 13/683,382, filed Nov. 21, 2012, now U.S. Pat. No. 8,585,191, issued Nov. 19, 2013, which is a continuation of application Ser. No. 12/858,620, filed Aug. 18, 2010, now U.S. Pat. No. 8,336,999, issued Dec. 25, 2012, which claims priority under 35 U.S.C. §119 on Japanese Patent Application No. 2009-202339, filed Sep. 2, 2009. Each of the above-identified related applications is expressly incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     1. Field of Invention 
     The present invention relates to a liquid ejecting apparatus in which liquid, such as ink, is supplied from a liquid storage unit to a liquid ejection unit. 
     2. Description of Related Art 
     Until now, an ink jet-type printer (hereinafter referred to as “printer”) disclosed in JP-A-2000-211152 has been proposed as a liquid ejecting apparatus capable of supplying a liquid from a liquid storage unit for storing the liquid to a liquid ejection unit. The printer disclosed in JP-A-2000-211152 includes a recording head serving as a liquid ejecting unit for ejecting ink as the liquid onto a target such as recording paper, and a sub-tank for temporarily accommodating the ink to be supplied to the inside of the recording head. The inside of the sub-tank is supplied with the ink from an ink cartridge, which serves as a liquid storage unit, via an ink supply tube. 
     Recently, as the ink to be ejected onto the target, UV (Ultra Violet) ink which is cured by irradiation of ultraviolet rays has been used. A portion of the ink component may be easily settled in the ink cartridge which stores the high viscosity ink, such as UV ink. For this reason, a component ratio of the ink supplied to the recording head via the sub-tank from the ink cartridge may vary slightly whenever a process of supplying the ink from the ink cartridge side is performed. Accordingly, a variation occurs in the component ratio of the ink ejected from the recording head, and, as a result, it is difficult to constantly maintain the quality of a product (i.e., a target of printing completion) made by ejecting the ink onto the target. 
     In addition, if the ink is accommodated in the sub-tank for a long time, a portion of the ink component may be settled in the sub-tank. In a case where the ink is supplied to the recording head side from the sub-tank in this state, a variation may occur in the component ratio of the ink which is ejected from the recording head. 
     SUMMARY OF INVENTION 
     An advantage of some aspects of the invention is that it provides an apparatus in which a liquid having a uniform component ratio can be supplied to a liquid ejecting apparatus. 
     According to an aspect of the invention, there is provided a liquid ejecting apparatus comprising a main tank configured to agitate a liquid accommodated in the main tank; a sub tank configured to receive the liquid supplied from the main tank; multiple heads that eject the liquid supplied from the sub tank; a liquid supply tube having connector tubes that branch off to the heads respectively; a pump configured to suck the liquid from the main tank and discharge such liquid to the sub tank; and a valve separated from the pump that operates to allow or restrict flow of the liquid between the main tank and the sub tank. 
     The main ink tank may include a drawer assembly, a portion of which is manually movable to agitate the liquid. Agitation may be carried out at set times to ensure that one or more components of the liquid does not settle in the main tank. 
     A residual amount sensor may be provided. The sensor enables accurate determination of the residual amount of the liquid in the main tank. 
     The main tank may be configured to have a size which can accommodate all of the liquid in the sub tank. That is, the capacity of the main tank is greater than that of the sub tank. This enables the supply of liquid having a uniform component ratio to the liquid ejecting apparatus. 
     In another other variations, the liquid ejecting apparatus further comprises liquid circulation tubes corresponding to the heads respectively, where the liquid in each head flows into the sub tank through the corresponding liquid circulation tube. Also, a supply passage heater may be provided to heat the liquid in the connector tubes. 
     The liquid may be UV ink that is cured by irradiation of ultraviolet rays. 
     Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings. 
    
    
     
       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 diagram schematically illustrating the configuration of an ink jet-type printer according to an embodiment of the invention. 
         FIGS. 2A and 2B  are diagrams schematically illustrating the configuration of a holder. 
         FIG. 3  is a sectional-side view schematically illustrating the internal configuration of a main tank. 
         FIG. 4  is a block diagram illustrating an electric configuration. 
         FIG. 5  is a flowchart illustrating a routine of processing ink supply. 
         FIG. 6  is a flowchart illustrating a routine of processing a sub-tank. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     One embodiment of the invention will be described with reference to  FIGS. 1 to 6 . 
     As shown in  FIG. 1 , an ink jet-type printer  11  (hereinafter referred to as a “printer”) serving as a liquid ejecting apparatus includes a printing section  12  capable of performing a printing process with respect to a target (e.g., a film or glass plate), which is not illustrated, by using UV (Ultra Violet) ink (ultraviolet curable ink) as one example of a liquid. In addition, the printer  11  of this embodiment is provided with an irradiation unit (not illustrated) that irradiates ultraviolet rays onto the target, on which the printing is completed by the printing section  12 , to cure the UV ink landed on the target. In this instance, the UV ink contains a pigment component with low dispersion stability, and also has a property of such that the pigment component is easily settled. 
     The printing section  12  includes a holder  14  on which an ink cartridge  13  serving as a liquid storage unit for storing the LTV ink is mounted, and a main tank  15  formed in a substantially cylindrical shape having a bottom surface and located below the holder  14  in the direction of gravity. The holder  14  is provided with a hollow ink supply needle  17  which can be attached to or detached from a derivation portion  16  of the ink cartridge  13  which is located at a mounting position indicated by a double-dotted chain line in  FIG. 1 . In addition, the holder  14  is connected to a first ink supply tube  18  serving as a liquid connection passage. The upstream end portion  18   a  of the first ink supply tube  18  is communicated with the inside of the ink supply needle  17  as a liquid connection passage, and the downstream end portion  18   b  of the first ink supply tube  18  is located in the inside of the main tank  15 . The main tank  15  is configured in such a way that the capacity of the UV ink is sufficiently larger than the storage amount of the UV ink in the ink cartridge  13 . The side wall of the main tank  15  is provided with a plurality (two in this embodiment) of main-side residual amount sensors  19  and  20  for detecting the residual amount of the UV ink in the main tank  15  based on the position of a liquid level A 1  of the UV ink. Each of the main-side residual amount sensors  19  and  20  is located at a different position in the direction of gravity. 
     In addition, the printing section  12  is provided with an agitation device  21  serving as an agitating unit for agitating the UV ink accommodated in the main tank  15 . The agitation device  21  includes an agitation motor  22  serving as a driving source, a shaft member  23 , serving as a rotation axis, which is rotated by the driving of the agitation motor  22 , and a plurality (only two illustrated in  FIG. 1 ) of blade members  24  installed at the front end (the lower end in  FIG. 1 ) of the shaft member  23 . 
     In addition, the printing section  12  is provided with a sub-tank  25  as another tank, of which the capacity of the UV ink is equal to or less than that of the main tank  15 , and a first liquid supply unit  26  serving as a liquid supplying unit for supplying the LTV ink to the inside of the sub-tank  25  from the main tank  15 . The first liquid supply unit  26  includes a second ink supply tube  27  as a liquid supply passage, of which the upstream end portion  27   a  is located in the main tank  15  and the downstream end portion  27   b  is connected to the sub-tank  25 , and a first pump  29  sucking the UV ink in the main tank  15  by the driving of the first driving motor  28  and discharging the UV ink to the sub-tank  25  side. In addition, the second ink supply tube  27  is provided with a first opening/closing valve (e.g., electro-magnetic valve)  30 , which operates to allow or restrict flow of the UV ink between the tanks  15  and  25 , at the sub-tank  25  side rather than the first pump  29 . 
     The sub-tank  25  includes a substantially cylindrical tank body having a bottom surface, and a cover portion closing an opening portion of the tank body. The side wall of the sub-tank  25  is provided with a sub-side residual amount sensor  31  for detecting the capacity of the UV ink temporarily accommodated in the sub-tank  25 . In a case where the liquid level A2 of the UV ink is at the same position as the installation position of the sub-side residual amount sensor  31  in the sub-tank  25  or is over the installation position, an “ON” signal is output from the sub-side residual amount sensor  31 . In addition, the sub-tank  25  is provided with a first temperature sensor  32  for detecting the temperature of the LTV ink in the sub-tank and a sub-tank heater  33  for heating the UV ink. Furthermore, the sub-tank  25  is connected to a compression/decompression unit  34  for compressing and decompressing the inside of the sub-tank  25 . 
     The compression/decompression unit  34  includes a second pump  36  that drives to feed the gas to the inside of the sub-tank  25  by a second driving motor  35  to compress the inside of the sub-tank  25 , and a second opening/closing valve (e.g., electro-magnetic valve)  37  that is in an open state in a case where the second pump  36  is driving or is in a closed state in a case where the second pump  36  is not driving. In addition, the compression/decompression unit  34  includes a third pump  39  that drives to exhaust the gas from the inside of the sub-tank  25  by a third driving motor  38  to decompress the inside of the sub-tank  25 , and a pressure opening valve  40  for opening the inside of the sub-tank  25  in the atmosphere. Moreover, the compression/decompression unit  34  is provided with a third opening/closing valve (e.g., electro-magnetic valve)  41  that is in an open state in a case where at least one of the third pump  39  and the pressure opening valve  40  is driving and is in a closed state in a case where both the third pump  39  and the pressure opening valve  40  are not driving. 
     In addition, the printing section  12  is provided with an ink ejection unit  42  for ejecting the UV ink onto the target, and the ink ejection unit  42  has a plurality (four in this embodiment) of recording heads (liquid ejecting units)  43 . Each of the recording heads  43  is provided with a pressure adjusting chamber (not illustrated) in the inside of the recording head. The UV ink in each of the pressure adjusting chambers is supplied to a plurality of nozzles (not illustrated) by the driving of a piezoelectric element (not illustrated), and then is appropriately ejected from each of the nozzles. In addition, each of the recording heads  43  is provided with a second temperature sensor  44  for detecting the temperature of the recording head, and a head heater  45  for keeping the UV ink in the pressure adjusting chamber warm. 
     Each of the recording heads  43  is supplied with the LTV ink from the sub-tank  25  via a second liquid supply unit  46 . The second liquid supply unit  46  includes a third ink supply tube  47  with the upstream end portion  47   a  located in the vicinity of the bottom portion of the sub-tank  25 . The downstream side of the third ink supply tube  47  is connected to a plurality (four in this embodiment) of connection tubes  48  corresponding to each of the recording heads  43 . Accordingly, in this embodiment, another liquid supply passage for supplying the UV ink to each of the recording heads  43  from the sub-tank  25  is formed by the third ink supply tube  47  and the connection tube  48 . In addition, the third ink supply tube  47  is provided with a fourth pump  50  for sucking the UV ink from the sub-tank  25  side in accordance with the driving of the fourth driving motor  49  to discharge the UV ink to each of the recording heads  43  side. Moreover, the third ink supply tube  47  is provided with a fourth opening/closing valve (e.g., electro-magnetic valve)  51  that operates to allow or restrict the flow of the LTV ink from the sub-tank  25  to each of the recording heads  43  side, and a damper  52  for damping fluctuation of the LTV ink supplied by the fourth pump  50  at each of the recording heads  43  side rather than the fourth pump  50 . 
     Each of the connector tubes  48  is configured in such a way that a passage sectional area of the connector tube is narrower than that of the third ink supply tube  47 . The UV ink flowing in each of the connector tubes  48  is heated by a supply passage heater  54  that is controlled based on the detected signal from the third temperature sensor  53 . 
     In addition, a plurality (four in this embodiment) ink circulation tubes  55  corresponding to each of the recording heads  43  is interposed between each of the recording heads  43  and the sub-tank  25 . Each of the ink circulation tubes  55  is configured in such a way that the upstream end portion  55   a  of the ink circulation tube is connected to each of the recording heads  43  and the downstream end portion  55   b  is located in the sub-tank  25 . Each of the ink circulation tubes  55  is provided with a fifth opening/closing valve (e.g., electro-magnetic valve)  56  that operates to allow or restrict the flow of the UV ink from each of the recording heads  43  side to the sub-tank  25  side. 
     In this instance, the printing section  12  includes a printing unit having the holder  14 , each tanks  15  and  25 , and the ink ejection unit  42  for each printing color as a configuration capable of ejecting UV ink of plural colors onto the target. However, only the printing unit for one color (e.g., white) will be described in this embodiment, and the description of the printing unit for other colors will be omitted for the sake of easy understanding of the specification. 
     Next, the ink cartridge  13  and the holder  14  will be described with reference to  FIGS. 2A and 2B . 
     As shown in  FIGS. 2A and 2B , the ink cartridge  13  includes a cartridge body  61  of a substantially rectangular parallelepiped shape which forms an ink storage chamber  60  (indicated by a dotted line in  FIGS. 2A and 2B ) for storing the UV ink therein. The bottom portion (left bottom portion in  FIGS. 2A and 2B ) of the cartridge body  61  is provided with the derivation portion  16  for deriving outwardly the UV ink from the ink storage chamber  60 . In this instance, a film for suppressing volatility of the ink solvent is attached to the derivation portion  16  of the unused ink cartridge  13 . 
     In addition, the cartridge body  61  is provided with an IC memory  62  in which various information such as the kinds of stored LTV ink (color information or the like) and a storage amount is stored, and an electrode terminal  63  serving as an access terminal of the IC memory  62 . In this instance, the IC memory  62  has a nonvolatile memory such as an EEPROM. 
     The holder  14  has a holder body  64 , with an upper portion of  FIG. 2A  being opened. The holder body  64  is provided therein with an accommodation space  65  for accommodating the ink cartridge  13  therein. A through-hole  66  is formed to penetrate the bottom portion  64   a  of the holder body  64  at a position corresponding to the derivation portion  16  of the ink cartridge  13 . The ink supply needle  17  is fitted into the through-hole  66 . A communication hole  17   a  is formed in the front end side (upper end side in  FIG. 2A ) of the ink supply needle  17  to communicate the inner portion and the outer portion of the ink supply needle. In addition, the bottom portion  64   a  of the holder body  64  is provided with a biasing member (coil spring or the like) (not illustrated) for biasing the ink cartridge  13  in an upward direction. The ink cartridge  13  is located at a position (position shown in  FIG. 2A ) by the biasing force from the biasing member, in which the ink supply needle  17  is not possibly to be inserted into the derivation portion  16  of the ink cartridge  13 . In this instance, the position of the ink cartridge  13  shown in  FIG. 2A  is referred to as a “standby position”. 
     In addition, the holder  14  is provided with a pressing device  67  which is positioned over the holder body  64  in  FIG. 2A  and is driven based on a control command from a control device  80  which will be described later. The pressing device  67  includes a press member  68  that comes into contact with the ink cartridge  13  to apply a press force to the ink cartridge towards the lower side in  FIG. 2A , and an attaching/detaching motor  69  to drive the press member  68  to advance and withdraw in an upward and downward direction in  FIG. 2A . In a case where the ink cartridge  13  located at the standby position is pressed in a downward direction in  FIG. 2A  by driving of the pressing device  67 , the ink cartridge  13  is moved in a downward direction against the biasing force from the biasing member. As a result, the ink supply needle  17  is inserted into the derivation portion  16  of the ink cartridge  13 , as shown in  FIG. 2B , and thus the LTV ink of the ink storage chamber  60  is derived to the main tank  15  side via the ink supply needle  17  and the first ink supply tube  18 . In this instance, the position of the ink cartridge  13  shown in  FIG. 2B  is referred to as a “mounting position”. 
     The side wall of the holder  14  is provided with two contact terminals  70   a  and  70   b  which are located along upward and downward directions in  FIGS. 2A and 2B , and each of the contact terminals  70   a  and  70   b  are electrically connected to the control device  80  which will be described later. In addition, in a case where the ink cartridge  13  is located at the standby position, the first contact terminal  70   a  of the contact terminals  70   a  and  70   b  which is positioned at the upper side is located at the position which comes into contact with the electrode terminal  63  of the ink cartridge  13 . In a case where the ink cartridge  13  is located at the mounting position, the second contact terminal  70   b  which is positioned at the lower side is located at the position which comes into contact with the electrode terminal  63  of the ink cartridge  13 . That is, even in the case where the ink cartridge  13  is located at the standby position or is located at the mounting position in this embodiment, if the ink cartridge  13  is mounted on the holder  14 , various information stored in the IC memory  62  can be read by the control device  80 . 
     Next, the internal configuration of the main tank  15  will be described with reference to  FIG. 3 . 
     As shown in  FIG. 3 , the first main-side residual amount sensor  19  which is positioned at the upper side of the main-side residual amount sensors  19  and  20  installed in the main tank  15  in the direction of gravity is located at the position in such a way that the main tank  15  can accommodate all the LTV ink stored in one ink cartridge  13 , in a case where the liquid level A 1  of the UV ink accommodated in the main tank  15  is positioned at a position equal to the installation position of the first main-side residual amount sensor  19 . In the case where the liquid level A 1  of the UV ink in the main tank  15  is positioned at a position equal to or higher than the installation position of the first main-side residual amount sensor  19 , an “ON signal” is output to the control device  80  from the first main-side residual amount sensor  19 . In this embodiment, the capacity of the UV ink, in the case where the liquid level A 1  of the LTV ink in the main tank  15  is positioned at a position equal to the installation position of the first main-side residual amount sensor  19 , is referred to as an “amount approximate to an upper limit”, and in this instance, the liquid level A 1  of the UV ink is referred to as a “level A 1  u approximate to the upper limit level”. 
     In addition, the second main-side residual amount sensor  20  which is positioned at the lower side in the direction of gravity is located at the position in such a way that the UV ink is supplied from the main tank  15  to the sub-tank  25  side to fill the inside of the sub-tank  25  with the LTV ink, in the case where the liquid level A 1  of the UV ink accommodated in the main tank  15  is positioned at a position equal to the installation position of the second main-side residual amount sensor  20 . In the case where the liquid level A 1  of the UV ink in the main tank  15  is positioned at a position equal to or higher than the installation position of the second main-side residual amount sensor  20 , an “ON signal” is output to the control device  80  from the second main-side residual amount sensor  20 . In this embodiment, the capacity of the UV ink, in the case where the liquid level A 1  of the UV ink is positioned at a position equal to the installation position of the second main-side residual amount sensor  20 , is referred to as an “amount approximate to a lower limit”, and in this instance, the liquid level A 1  of the UV ink is referred to as a “level A 1 d approximate to lower limit”. 
     The shaft member  23  of the agitation device  21  in the main tank  15  is located at the same position as a center line (indicated by a one-dotted chain line in  FIG. 3 )  15   a  of the main tank  15 . That is, the shaft member  23  is located to be extended along the direction of gravity, and the front end (i.e., the lower end) of the shaft member  23  is positioned at a position lower than the installation position of the second main-side residual amount sensor  20 . In a case where each of the blade members  24  installed at the front end of the shaft member  23  is rotated together with the shaft member  23  in the arrow direction shown in  FIG. 3 , the blade member is configured draw the UV ink from the upper portion of each of the blade members  24  and discharge it toward the lower portion of each blade member  24 . That is, a suction pressure region Pa (region enclosed by the two-dotted chain line in  FIG. 3 ), in which pressure is lower than the other region, is formed just over each blade member  24  in the main tank  15 . In addition, a discharge pressure region Pb (region enclosed by the two-dotted chain line in  FIG. 3 ), in which pressure is higher than the other region, is formed just below each blade member  24 . As a result, convection of the UV ink indicated by an arrow in  FIG. 3  is created in the main tank  15  to agitate the UV ink in the main tank  15 . 
     In  FIG. 3 , the downstream end portion  18   b  of the first ink supply tube  18  is located at the left side of the shaft member  23  in  FIG. 3 , and is at a position higher than the installation position of the first main-side residual amount sensor  19  in the direction of weight. In addition, the downstream end portion  18   b  of the first ink supply tube  18  is bent so as to orient the sidewall (hereinafter referred to as “guide wall portion  71 ”) positioned at the left side of the sidewalls of the main tank  15  in  FIG. 3 . The LTV ink derived from the downstream end portion  18   b  of the first ink supply tube  18  is guided downwardly to the guide wall portion  71  of the main tank  15 , and thus is dipped in the LTV ink previously accommodated in the main tank  15 . That is, the UV ink flows down along the guide wall portion  71  of the main tank  15 . Accordingly, in this embodiment, the guide wall portion  71  functions as a guide portion for guiding downwardly the UV ink derived from the downstream end portion  18   b  of the first ink supply tube  18  in the direction of gravity. In this instance, the first ink supply tube  18  is configured to have flow passage resistance (e.g., a passage sectional area) against the LTV ink in such a way that bubbles does not mix in the UV ink in the main tank  15  when the UV ink dips to the liquid level A 1  through the guide wall portion  71 . 
     In  FIG. 3 , a second ink supply tube  27  is disposed at the right side of the shaft member  23 . That is, the upward end portion  27   a  of the second ink supply tube  27  is disposed at an opposite side of the downstream end portion  18   b  of the first ink supply tube  18 , with the shaft member  23  being interposed between the second ink supply tube and the first ink supply tube. The upward end portion  27   a  of the second ink supply tube  27  is disposed over each blade member  24  in the direction of gravity, and is disposed below the installation position of the second main-side residual amount sensor  20 . In this instance, the corresponding volume between the installation position of the second main-side residual amount sensor  20  and the installation position of the upstream end portion  27   a  of the second ink supply tube  27  is set to be slightly larger than the corresponding volume between the bottom portion of the sub-tank  25  and installation position of the sub-side residual amount sensor  31 . 
     Next, the electric configuration of the printing unit  12  according to this embodiment will be described with reference to  FIG. 4 . In this instance, the portions requiring the supply of the UV ink from the ink cartridge  13  to the sub-tank  25  are mainly shown in  FIG. 4 , and illustrations of the other portions are omitted. 
     As shown in  FIG. 4 , the input/output interface of the control device  80  is electrically connected with each contact terminal  70   a  and  70   b , the attaching/detaching motor  69 , the agitation motor  22 , the first driving motor  28 , the first opening/closing valve  30 , the compression/decompression unit  34  and each residual amount sensor  19 ,  20  and  31 . The control device  80  is provided with an ink supply control unit  81  mainly conducting the supply of the ink from the ink cartridge  13  to the sub-tank  25 , and a printing control unit  82  mainly conducting the printing processing on the target. In addition, the control device  80  is provided with a driver circuit (not illustrated) for the attaching/detaching motor  69 , a driver circuit (not illustrated) for the agitation motor  22 , a driver circuit (not illustrated) for the first driving motor  28 , a driver circuit (not illustrated) for the first opening/closing valve  30 , and a driver circuit (not illustrated) for the compression/decompression unit  34 . 
     The ink supply control unit  81  includes a CPU, a ROM and a RAM (not illustrated). In addition, the printing control unit  82  includes a CPU, a ROM, a RAM, an ASIC (Application Specific Integrated Circuit) (not illustrated) or the like. 
     Next, an ink supply processing routine which is executed by the ink supply control unit  81  of the control device  80  will be described with reference to a flowchart shown in  FIGS. 5 and 6 . 
     First, the ink supply control unit  81  executes the ink supply processing routine every predetermined desired cycle (e.g., one second). In the ink supply processing routine, the ink supply control unit  81  determines whether a power ON flag FLG 1  is ON or not (step S 10 ). The power ON flag FLG 1  is a flag which is set to be ON in a case where the power of the printer  11  is turned ON and then the UV ink accommodated in the main tank  15  is agitated. If the determination result of step S 10  is a negative determination (FLG 1 =OFF), the ink supply control unit  81  determines that agitation is not performed even once on the UV ink, sets the power ON flag FLG 1  to ON (step S 11 ), and then carries out the processing to step S 22  which will be described below. 
     Meanwhile, if the determination result of step S 10  is a positive determination (FLG 1 =ON), the ink supply control unit  81  determines whether or not an elapsed time Tk, after the agitation processing which will be described is finally performed, is less than a predetermined elapsed time threshold value KTk 1  (e.g., a value corresponding to one week) (step S 12 ). If the agitation on the UV ink in the main tank  15  is not performed during the time corresponding to the elapsed time threshold value KTk 1 , the UV ink pigment component may be settled in the main tank  15 . Accordingly, the elapsed time threshold value KTk 1  is a reference value to determine whether the sedimentation of the UV ink pigment component happens from the elapsed time Tk, and is set in advance by an experiment or simulation. If the determination result of step S 12  is a negative determination (Tk≧KTk 1  ), the ink supply control unit  81  determines that the sedimentation of the UV ink pigment component may have occurred in the main tank  15 , and then carries out the processing to step S 22  which will be described below. 
     Meanwhile, if the determination result of step S 12  is a positive determination (Tk&lt;KTk 1 ), the ink supply control unit  81  detects the ink residual amount IQsub of the LTV ink accommodated in the sub-tank  25  (step S 13 ). More specifically, the ink supply control unit  81  detects the supply amount of the LTV ink from the main tank  15  to the sub-tank  25  based on the driving velocity and driving time of the first pump  29 . In addition, the printing control unit  82  performs the measurement on the ejection amount of the UV ink when the UV ink is ejected from the nozzle of each recording head  43 . Accordingly, the ink supply control unit  81  obtains the ink residual amount IQsub in the sub-tank  25  by subtracting the total amount of the UV ink to be supplied to the sub-tank  25  from the main tank  15  by the total amount of the ink to be ejected from each recording head  43 . Consequently, step S 13  corresponds to the residual amount detection step in this embodiment. 
     Next, the ink supply control unit  81  determines whether the ink residual amount IQsub detected in step S 13  is equal to or less than the predetermined residual amount threshold value KIQsub (step S 14 ). The residual amount threshold value KIQsub is a reference value which is set in such a way that the liquid level A 2  of the UV ink in the sub-tank  25  is not positioned below the upstream end portion  47   a  of the third ink supply tube  47 , and is set in advance by an experiment or simulation. If the determination result of step S 14  is a negative determination (IQsub&gt;KIQsub), the ink supply control unit  81  determines that the capacity of the UV ink in the sub-tank  25  is sufficient, and then carries out the processing to step S 18  which will be described below. 
     Meanwhile, if the determination result of step S 14  is a positive determination (IQsub≦KIQsub), the ink supply control unit  81  determines whether or not the elapsed time Tk, after the agitation processing is finally performed, is equal to or more than a predetermined regulated time-threshold value KTk 2  (step S 15 ). If the UV ink in the main tank  15  is agitated by the agitation device  21 , bubbles may be mixed with the LTV ink. In a case where the UV ink is supplied from the main tank  15  to the sub-tank  25 , the LTV ink mixed with bubbles may be supplied to the sub-tank  25 . If the UV ink mixed with bubbles is supplied to each recording head  43  from the sub-tank  25 , ejection failure of the UV ink may happen. For this reason, after the agitation processing is performed, it would be better to wait until bubbles mixed with the UV ink are outwardly discharged. Accordingly, as a value corresponding to the standby time after the agitation processing in this embodiment, the regulation time threshold value KTk 2  is set in advance. 
     If the determination result of step S 15  is a negative determination (Tk&lt;KTk 2 ), the ink supply control unit  81  determines that bubbles may be still mixed with the UV ink in the main tank  15 , and executes the determination processing of step S 15  repeatedly until the determination result of step S 15  is a positive determination. Meanwhile, if the determination result of step S 15  is a positive determination (Tk≧KTk 2 ), the ink supply control unit  81  determines whether a supply stop flag FLG 2  is OFF or not (step S 16 ). The supply stop flag FLG 2  is a flag which is set to be ON in a case where it is determined that the supply of the UV ink to the sub-tank  25  is difficult since the residual amount of the ink in the main tank  15  is excessively small, that is, the capacity of the UV ink is sufficiently less than the amount approximate to the lower limit. If the determination result of step S 16  is a negative determination (FLG 2 =ON), the ink supply control unit  81  restricts the supply of the UV ink to the sub-tank  25 , and then carries out the processing to step S 19  which will be described below. Meanwhile, if the determination result of step S 16  is a positive determination (FLG 2 =OFF), the ink supply control unit  81  executes the sub-tank supply processing (will be described in detail in  FIG. 6 ) to supply the UV ink to the sub-tank  25  (step S 17 ), and then carries out the processing to next step S 18 . Accordingly, step S 17  corresponds to the second supply step in this embodiment. 
     In step S 18 , the ink supply control unit  81  determines whether the detection signal from the first main-side residual amount sensor  19  is an OFF signal or not. That is, it is determined in step S 18  whether or not the liquid level A 1  of the UV ink in the main tank  15  is positioned at a position equal to or higher than the installation position of the first main-side residual amount sensor  19 . In other words, in step S 18 , detected is the capacity of the UV ink in the main tank  15  based on the detection signal from the first main-side residual amount sensor  19 . Accordingly, step S 18  corresponds to the capacity detecting step in this embodiment. 
     If the determination result of step S 18  is a negative determination, the ink supply control unit  81  determines that the capacity of the UV ink in the main tank  15  is equal to or more than the approximate amount of the predetermined upper limit, and thus completes first the ink supply processing routine without performing the supply of the ink to the main tank  15 . Meanwhile, if the determination result of step S 18  is a positive determination, the ink supply control unit  81  carries out the processing to next step S 19 . 
     In step S 19 , the ink supply control unit  81  determines whether or not the ink cartridge  13  stored with the UV ink therein is mounted on the holder  14 . More specifically, the ink supply control unit  81  determines that the ink cartridge is mounted on the holder in a case where the information can be acquired from the IC memory  62  of the ink cartridge  13  through the contact terminal  70   a . In this instance, the ink supply control unit  81  determines that the ink cartridge  13  is not mounted on the holder  14  in a case where the information indicating that the storage amount of the UV ink in the ink cartridge  13  is zero 0 or nearly zero 0 is detected from IC memory  62 . If the determination result of step S 19  is a negative determination, the ink supply control unit  81  carries out the notification processing of notifying a command of mounting the ink cartridge  13  on the holder  14  (step S 20 ), and then first completes the ink supply processing routine. If the notification processing is performed, for example, the command of mounting the ink cartridge  13  on the holder  14  is displayed on a display screen of a computer, which is not illustrated, connected to the printer  11 . 
     Meanwhile, the determination result of step S 19  is a positive determination, the ink supply control unit  81  carries out the main tank supply processing to supply the UV ink to the main tank  15  (step S 21 ). That is, the ink supply control unit  81  controls the driving of the attaching/detaching motor  69  to move the press member  68  in a downward direction and move the ink cartridge  13  positioned at the standby position to the mounting position. Then, in a case where the elapsed time after the ink cartridge  13  is disposed at the mounting position passes a predetermined time, the ink supply control unit  81  determines that all the UV ink in the ink cartridge  13  is supplied to the main tank  15 . The ink supply control unit  81  controls the driving of the attaching/detaching motor  69  to move the press member  68  in an upward direction and move the ink cartridge  13  from the mounting position to the standby position, and then carries out the processing to the next step S 21 - 1 . Accordingly, the first supply step is constituted of steps S 19  to S 21  in this embodiment. 
     In step S 21 - 1 , the ink supply control unit  81  sets the supply stop flag FLG 2  as OFF, and then carries out the processing to next step S 22 . 
     In step S 22 , the ink supply control unit  81  performs the agitation processing of agitating the UV ink in the main tank  15 . More specifically, the ink supply control unit  81  controls the driving of the agitation motor  22  to rotate each blade member  24 . In a case where the elapsed time, after each blade member  24  starts to rotate, passes the predetermined rotation time threshold value, the ink supply control unit  81  determines that the LTV ink in the main tank  15  is sufficiently agitated, and then stops the agitation motor  22 . Accordingly, step S 22  corresponds to the agitation step in this embodiment. 
     Then, the ink supply control unit  81  resets the elapsed time Tk after completion of the final agitation process as zero 0 (step S 23 ). After that, the ink supply control unit  81  just completes the ink supply processing routine. 
     Next, the sub-tank supply processing (sub-tank supply processing routine) will be described based on the flowchart shown in  FIG. 6 . 
     First, in the sub-tank supply processing routine, the ink supply control unit  81  determines whether the detection signal of the second main-side residual amount sensor  20  is an OFF signal or not (step S 30 ). If the determination result is a positive determination, the ink supply control unit  81  determines that the capacity of the UV ink in the main tank  15  is equal to or less than the amount approximate to the lower limit, sets the supply stop flag FLG 2  as ON (step S 31 ), and then carries out the processing to step S 33  which will be described below. If the determination result is a negative determination in step S 30 , the ink supply control unit  81  determines that the capacity of the UV ink in the main tank  15  is more than the amount approximate to the lower limit, sets the supply stop flag FLG 2  as OFF (step S 32 ), and then carries out the processing to next step S 33 . 
     In step S 33 , the ink supply control unit  81  operates the third opening/closing valve  41  and the pressure opening valve  40  to open the inside of the sub-tank  25  to the air. The ink supply control unit  81  operates the first opening/closing valve  30  in the open state (step S 34 ), and then controls the first driving motor  28  to drive the first pump  29  (step S 35 ). The ink supply control unit  81  determines whether the detection signal from the sub-side residual amount sensor  31  is an ON signal or not (step S 36 ). If the determination result is a negative determination, the ink supply control unit  81  determines that the liquid level A 2  of the UV ink in the sub-tank  25  is positioned at a position lower than the installation position of the sub-side residual amount sensor  31 , and carries out the determination processing of step S 36  repeatedly until the determination result of step S 36  is the positive determination. 
     Meanwhile, if the determination result is a positive determination in step S 36 , the ink supply control unit  81  determines that the liquid level A 2  of the UV ink in the sub-tank  25  is positioned at a position equal to or higher than the installation position of the sub-side residual amount sensor  31 , and stops the first driving motor  28  to stop the first pump  29  (step S 37 ). Then, the ink supply control unit  81  operates the pressure opening valve  40  and the third opening/closing valve  41  of the compression/decompression unit  34  in a closed state, and simultaneously operates the first opening/closing valve  30  in a closed state (step S 38 ). After that, the ink supply control unit  81  completes the sub-tank supply processing routine. 
     Next, a method of supplying the UV ink in the printer  11  according to this embodiment will be described. 
     First, if the liquid level A 1  of the UV ink in the main tank  15  is positioned at a position equal to or lower than the installation position of the first main-side residual amount sensor  19  in the direction of gravity, it starts to supply the UV ink to the main tank  15 . That is, the ink cartridge  13  installed on the holder  14  moves from the standby position (refer to  FIG. 2A ) to the mounting position (refer to  FIG. 2B ) by the driving of the press device  67 . The ink supply needle  17  is inserted into the derivation portion  16  of the ink cartridge  13 , and the UV ink in the ink storage chamber  60  of the ink cartridge  13  is derived through the ink supply needle  17  and the first ink supply tube  18 . In this instance, the UV ink derived from the downstream end portion  18   b  of the first ink supply tube  18  is guided in a downward direction along the guide wall portion  71  opposite to the downstream end portion  18   b . As a result, when the UV ink supplied from the ink cartridge  13  dips to the liquid level A 1  of the UV ink previously supplied to the main tank  15 , it is possible to suppress bubbles from being mixed with the LTV ink in the main tank  15 . 
     If all the UV ink in the ink cartridge  13  is supplied to the main tank  15 , the ink cartridge  13  installed at the mounting position is moved to the standby position, and the supply of the UV ink to the main tank  15  is completed. Then, the LTV ink to be accommodated in the main tank  15  is agitated in the main tank  15 . That is, each of the blade members  24  is rotated in a direction indicated by the arrow in  FIG. 3  by the driving of the agitation motor  22 . The suction pressure region Pa is formed in the region over each blade member  24 , and simultaneously, the discharge pressure region Pb is formed in the region below each blade member  24 . As a result, the convection of the UV ink indicated by the arrow in  FIG. 3  is created in the main tank  15  to agitate the LTV ink in the main tank  15 . For this reason, although the pigment component has settled in the vicinity of the bottom portion of the main tank  15 , the component ratio of the LTV ink in the main tank  15  can be stabilized by the agitation processing using the agitation device  21 . In this instance, the ‘stabilization of the component ratio’ herein indicates that the component ratios of the LTV ink are substantially equal to each other at plural different positions in the main tank  15 . 
     If the agitation processing is completed, bubbles may be mixed with the LTV ink in the main tank  15  by the agitation. For this reason, until the time corresponding to the regulation time threshold value KTk 2  passes after the agitation processing is completed, the supply of the UV ink from the main tank  15  to the sub-tank  25  side is restricted. 
     After that, if the liquid level A 2  of the UV ink in the sub-tank  25  is positioned at the position substantially equal to the upstream end portion  47   a  of the second liquid supply unit  46  in the direction of gravity, the LTV ink is supplied to the sub-tank  25  from the main tank  15 . In this instance, the inside of the sub-tank  25  is opened to the air by the operation of the pressure opening valve  40  and the third opening/closing valve  41  of the compression/decompression unit  34 . In this instance, if the first opening/closing valve  30  is opened and simultaneously the first pump  29  is driven, the UV ink in the main tank  15  is supplied to the sub-tank  25  through the second ink supply tube  27 . Then, the liquid level A 2  of the UV ink in the sub-tank  25  is gradually increased. If the liquid level A 2  of the UV ink in the sub-tank  25  is positioned at the position equal to or higher than the installation position of the sub-side residual amount sensor  31 , the supply of the UV ink to the sub-tank  25  is stopped. That is, the pressure opening valve  40  and the third opening/closing valve  41  of the compression/decompression unit  34  are in the closed state, and simultaneously, the driving of the first pump  29  is stopped. In addition, the first opening valve  30  is in the closed state. 
     In this instance, in a case where the supply start timing of the UV ink to the sub-tank  25  is overlapped with the supply start timing of the LTV ink to the main tank  15 , the supply of the UV ink to the sub-tank  25  is first carried out. That is, the supply of the UV ink to the sub-tank  25  is completed, and then the UV ink is supplied to the main tank  15 . In addition, in a case where the ink cartridge  13  is not mounted on the holder  14  at the supply start timing of the UV ink to the main tank  15 , a notification urging the user to mount the ink cartridge  13  is performed. 
     Consequently, the following effects can be obtained in this embodiment. 
     (1) It is possible to supply the UV ink to the main tank  15  from the ink cartridge  13 . By agitating the UV ink supplied to the main tank  15 , it is possible to suppress a portion (in this instance, the pigment component) of the UV ink component from being settled in the main tank  15 . That is, it is possible to supply the UV ink with a uniform component ratio to the recording head  43 . For this reason, it is possible to always eject the UV ink with a uniform component ratio onto the target, and stabilize the quality of the printed product (i.e., the target of the printing completing) by the printer  11 . 
     (2) The UV ink in the ink cartridge  13  is supplied to the main tank  15  through the first ink supply tube  18  and the guide wall portion  71 . In this instance, since the UV ink is guided in the downward direction by the guide wall portion  71 , it is possible to suppress bubbles from being created in the UV ink in the main tank  15 , when the UV ink dips to the liquid level A 1  of the UV ink previously accommodated in the main tank  15 . Accordingly, it is possible to suppress bubbles mixed with the LTV ink from being supplied to the recording head  43  together with the UV ink. Also, it is possible to suppress generation of ejection failure of the LTV ink by the recording head  43 . 
     (3) In this embodiment, a portion (i.e., the guide wall portion  71 ) of the sidewall of the main tank  15  serves as a guide portion. For this reason, it is possible to simplify the whole apparatus as compared with the case in which a guide portion is installed separately from the sidewall in the main tank  15 . 
     (4) In general, the UV ink pigment component may be settled in the lower portion of the main tank  15  rather than the blade member  24 . For this reason, in the case where the upward end portion  27   a  of the second ink supply tube  27  is disposed at a position lower than the blade member  24 , the pigment component precipitates, and thus UV ink with a component ratio differing from the regular component ratio may be supplied to the recording head  43  side. In this regard, the upward end portion  27   a  of the second ink supply tube  27  is disposed at the position higher than the blade member  24  in this embodiment. For this reason, it is possible to suppress the LTV ink different from the regular component ratio from being supplied to the recording head  43  side. 
     (5) In addition, in this embodiment, the blade member  24  is rotated to generate convection as shown by the arrow in  FIG. 3 . For this reason, even though the pigment component has settled in the main tank  15 , it is possible to solve the problem of the sedimentation appropriately. 
     (6) In the vicinity of the portion in which the LTV ink from the ink cartridge  13  is dipped in the main tank  15 , the component ratio of the UV ink may be different from the regular component ratio in accordance with the circumference in the ink cartridge  13 . For this reason, by disposing the downstream end portion  18   b  of the first ink supply tube  18  at the position spaced apart from the upstream end portion  27   a  of the second ink supply tube  27 , it is possible to suppress the UV ink with the component ratio from being supplied to the recording head  43  side. 
     (7) In this embodiment, even though the liquid level A 1  of the UV ink is positioned at the position equal to the installation position of the second main-side residual amount sensor  20  in the main tank  15 , the UV ink in the main tank  15  can be agitated by the rotation of the blade member  24 . In addition, the UV ink in the main tank  15  can be supplied to the recording head  43  side. For this reason, it is possible to suppress the ejection of the UV ink onto the target from being stopped. 
     (8) In the case where the liquid level A 1  of the UV ink in the main tank  15  is positioned at the position equal to or higher than the installation position of the first main-side residual amount sensor  19 , the main tank  15  doesn&#39;t have the space to accommodate all the UV ink in the ink cartridge  13 . For this reason, the supply of the UV ink to the main tank  15  is restricted. That is, the supply of the LTV ink to the main tank  15  from the ink cartridge  13  little by little is avoided, and the UV ink with a uniform component ratio can be supplied to the recording head  43  side. 
     (9) In the case where the capacity of the UV ink in the sub-tank  25  is reduced, the UV ink in the main tank  15  is supplied to the sub-tank  25 , and the UV ink is supplied to the recording head  43  from the sub-tank  25 . That is, in the case where it is necessary to supply the ink to the sub-tank  25 , it is possible to perform the supply of the UV ink to the sub-tank  25  from the main tank  15 . 
     (10) Immediately after the UV ink is supplied to the main tank  15  from the ink cartridge  13 , bubbles can be mixed with the UV ink accommodated in the main tank  15 . For this reason, in the case where the supply start timing of the UV ink to the main tank  15  is overlapped with the supply start timing of the UV ink to the sub-tank  25 , the supply of the UV ink to the sub-tank  25  is first carried out. Therefore, it is possible to suppress the supply of the UV ink mixed with bubbles to the sub-tank  25  side from the main tank  15 . 
     (11) The agitation of UV ink in the main tank  15  is periodically carried out. For this reason, even though the UV ink is accommodated in the main tank  15  for a long time and thus the pigment component settles, it is possible to solve the problem of the sedimentation periodically. 
     (12) In this embodiment, the agitation processing is carried out when electric power is supplied to the printer  11 . For this reason, even though the pigment component has settled in the main tank  15  while the power of the printer  11  is turned off, it is possible to solve the problem of the sedimentation of the pigment component in the main tank  15  by the agitation processing which is carried out immediately after the input of the electric power to the printer  11 . 
     (13) In addition, in the case where the UV ink is supplied to the main tank  15  from the ink cartridge  13 , the component ratios of the UV ink may be different at each position in the main tank  15 . Accordingly, in this embodiment, the agitation processing is carried out when supplying the UV ink to the main tank  15 . For this reason, the UV ink with a uniform component ratio can be supplied to the recording head  43  side. 
     (14) In this embodiment, the UV ink is temporarily accommodated in the sub-tank  25  from the main tank  15 , and then is supplied to the recording head  43 . For this reason, even though the UV ink supplied from the main tank  15  is mixed with bubbles, bubbles are outwardly discharged from the UV ink while the UV ink is temporarily accommodated in the sub-tank  25 . Therefore, it is possible to suppress the supply of the UV ink mixed with bubbles to the recording head  43 , and thus it is possible to suppress the generation of ejection failures of the UV ink. 
     In this instance, the embodiment may be altered into the following embodiments. 
     In an embodiment, the notification processing may be notification by sound. 
     In an embodiment, the printing unit  12  may include a plurality of sub-tanks  25  each corresponding to each recording head  43 . In this instance, the first liquid supply unit  26  may be formed for each sub-tank  25 . 
     In an embodiment, the sub-tank  25  may be omitted from the printing unit  12 . In this instance, each of the recording heads  43  is directly supplied with the UV ink from the main tank  15 . 
     In an embodiment, as the sensor for detecting the capacity of the accommodated UV ink, a float sensor may be installed in the main tank  15 . With this configuration, it is possible to appropriately detect the capacity of the UV ink in the main tank  15 . 
     In an embodiment, the main tank  15  may be provided with an arbitrary number of, that is, three or more, residual amount sensors. In this instance, each of the residual amount sensors may be disposed at different positions in the direction of gravity. 
     In an embodiment, the sub-tank  25  may be provided with an arbitrary number of, that is, two or more (e.g.,  2 ), residual amount sensors. In this instance, each of the residual amount sensors may be disposed at different positions in the direction of gravity. 
     In an embodiment, the upstream end portion  27   a  of the second ink supply tube  27  may be disposed at a position in the vicinity of the downstream end portion  18   b  of the first ink supply tube  18 . With the configuration, since the UV ink sufficiently agitated in the main tank  15  is supplied to the sub-tank  25  via the second ink supply tube  27 , the UV ink with the uniform component can be supplied to the recording head  43  side. 
     In an embodiment, the blade member  24  may be configured to rotate so as to generate the suction pressure region Pa at a lower portion and generate the discharge pressure region Pb at an upper portion. 
     In an embodiment, the agitation device  21  may be arbitrarily configured if the UV ink in the main tank  15  can be agitated. For example, the agitation device  21  may include a rotator disposed in the main tank  15 , and a driving source for generating a magnetic field at an outer portion of the main tank  15  to rotate the rotator in the main tank  15 . In addition, the agitation device  21  may agitate the UV ink in the main tank  15  by transferring ultrasonic waves or mechanical vibrations to the main tank  15 . Moreover, the agitation device  21  may include a pump for forcibly fluidizing the UV ink into the main tank  15 . 
     In an embodiment, the downstream end portion  18   b  of the first ink supply tube  18  may not be opposite to the sidewall of the main tank  15 . In this instance, it is preferable that the main tank  15  is provided therein with a guide portion for guiding the UV ink derived from the downstream end portion  18   b  of the first ink supply tube  18  such that the UV ink dips to the liquid level A 1  of the UV ink previously accommodated in the main tank  15 . In the case where the guide portion is installed, the downstream end portion  18   b  of the first ink supply tube  18  may be disposed at the outside of the main tank  15 . 
     In an embodiment, the UV ink derived from the downstream end portion  18   b  of the first ink supply tube  18  may be supplied to the inside of the main tank  15  without passing through the guide portion. In this instance, when the UV ink is supplied to the inside of the main tank  15 , the LTV ink may be mixed with bubbles, but after the agitation processing, the supply restriction period of the LTV ink to the sub-tank  25  side is set. For this reason, with the above configuration, it is possible to suppress the supply of the UV ink mixed with bubbles to the sub-tank  25  side. 
     In an embodiment, the holder  14  may be configured such that the ink supply needle  17  is inserted into the derivation portion  16  of the ink cartridge  13  mounted on the holder  14 . In this instance, the flow passage of the first ink supply tube  18  may be provided with an opening/closing valve which is opened and closed in accordance with the control command from the control device  80 . Therefore, when the UV ink is supplied to the main tank  15 , the opening/closing valve is opened. 
     In an embodiment, the main tank  15  may be disposed at a position higher than the ink cartridge  13  mounted on the holder  14  in the direction of gravity. In this instance, the flow passage of the first ink supply tube  18  may be provided with a pump which is driven when the LTV ink is supplied to the main tank  15 . 
     In an embodiment, the ink cartridge  13  disposed at the standby position may be manually disposed at the mounting position. In this instance, it is preferable that the notification of disposing the ink cartridge  13  at the mounting position is performed with respect to the user at the start timing of the first supply step. 
     In an embodiment, in the case where the printing is not performed towards a target, the UV ink can be supplied to the sub-tank  25  side from the main tank  15 , irrespective of the elapsed time after the agitation processing is completed. In this instance, even though the LTV ink mixed with bubbles is supplied to the inside of the sub-tank  25 , it is possible to naturally discharge outward the bubbles contained in the UV ink while the UV ink is temporarily accommodated in the sub-tank  25 . 
     In an embodiment, the agitation step may be initiated while the first supply step is performed. 
     In an embodiment, in a case where the elapsed time Tk after the agitation processing can be measured while the power of the printer  11  is turned off, the agitation processing may not necessarily be performed when the electric power is input to the printer  11 . That is, in a case where the elapsed time Tk is less than the elapsed time threshold value KTk 1  when the electric power is input to the printer  11 , the agitating processing may not be performed. In this instance, it is possible to quickly initiate the printing processing with respect to the target. 
     In an embodiment, the sub-tank  25  may be provided with an arbitrary number (e.g., two) of at least two residual amount sensors. In this instance, in the case where the liquid level A 2  of the UV ink is positioned at the position lower than the installation position of the residual amount sensor disposed at the lower side, the second supply step may be performed. 
     In an embodiment, the liquid storage unit for storing the UV ink may be formed in a drum or an envelope. 
     In this embodiment, although the printer  11  using the UV ink is exemplified, the invention is not limited thereto. A printer using other pigment ink may be exemplified. That is, a printer with ink, in which a portion of the components has settled during long reservation, may be exemplified. 
     In the above-described embodiment, although the ink jet-type printer  11  is exemplified as the liquid ejecting apparatus, aspects of the invention may be embodied as a liquid ejecting apparatus that ejects or discharges a liquid other than ink (including a liquid body in which particles of functional material are dispersed or mixed, liquid and a flowage body such as gel). For example, the liquid ejecting apparatus may be a liquid body ejecting apparatus that ejects a liquid body in which a material such as an electrode material or a color material (pixel material), which is used for manufacturing a liquid crystal display, an EL (electroluminescent) display, or a surface emitting display, is dispersed or dissolved, a liquid ejecting apparatus that ejects a bio organic used to manufacture bio chips, or a liquid ejecting apparatus that is used as a precision pipette to eject a sample of liquid. Furthermore, the liquid ejecting apparatus may be a liquid ejecting apparatus that ejects a pinpoint of a lubricant onto a precision machine such as watch or camera, a liquid ejecting apparatus that ejects a transparent resin liquid, such as an ultraviolet curing resin, for forming a microscopic semi-spherical lens (optical lens) used for an optical communication element, or the like, on a substrate, a liquid ejecting apparatus that ejects an etching solution such as acid or alkali to etch a substrate or the like, or a flowage body ejecting apparatus that ejects flowage body such as gel (e.g., physical gel). The invention may be applied to any one of the liquid ejecting apparatuses.