Patent Publication Number: US-8109601-B2

Title: Printer

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Japanese Application No. 2007-111465, filed on Apr. 20, 2007, the entire contents of which are herein incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to printers for printing on a print medium by ejecting ink droplets on the print medium, and maintenance devices for such printers. 
     2. Discussion of the Background 
     One type of printer is configured as an apparatus that includes a print head with nozzles for ejecting ink droplets, and which prints by reciprocating the print head along a guide rail in left-and-right directions on a print medium and ejecting ink droplets through the nozzles to the print medium. Such a printer can be provided near an end of the guide rail with a maintenance device for performing maintenance on the nozzles. The maintenance device is placed at a position where the print head stands by during no printing operation of the printer (hereinafter, called a “standby position”) and is provided with an ink receiving chamber that opens at its upper surface facing the nozzles. 
     Since ink remains at an end of the nozzle for a long period of time when the print head is in the standby position, the ink may solidify so that the nozzle end becomes clogged. In order to prevent such clogging, a residual ink is ejected from the nozzle to the ink receiving chamber at certain intervals of time. During this procedure, the ejected residual ink is received by the ink receiving chamber and is sent to a waste liquid tank, where the ink is collected in the waste liquid tank. When a certain amount of residual ink is collected, the waste liquid tank is detached from the printer and the residual ink is discarded and thus wasted. Such a printer configuration as mentioned above is shown in JP-A-2002-79692, for example. 
     However, problems associated with such a waste liquid tank configuration have been identified. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, a printer is provided that includes a medium supporting member configured to support a print medium, where the medium supporting member has a predetermined width in a left-right direction, a print head disposed to face the medium supporting member in a vertical direction, and a maintenance device disposed to face a lower surface of the print head when the print head is in a first position at one end of a reciprocating movement of the print head. The print head has nozzles for ejecting ink droplets downward, and the print head is configured to freely reciprocate above the medium supporting member in the left-right direction. The printer is configured to print on the print medium by ejecting printing ink droplets from the nozzles to the print medium while reciprocating the print head. The maintenance device is configured to receive residual ink ejected from the nozzles when the print head is in the first position. The maintenance device includes an ink receiving chamber configured to open upward to receive the residual ink ejected from the nozzles, and a liquid injection member configured to inject liquid into the ink receiving chamber when the print head is away from the first position where the print head faces the ink receiving chamber in the vertical direction. 
     In another aspect of the invention, a printer is provided that includes a medium supporting member configured to support a print medium, a print head disposed to face the medium supporting member, and a maintenance device including an ink receiving chamber disposed to face a lower surface of the print head when the print head is in a first position along the width of the medium supporting member. The print head has nozzles for ejecting ink droplets toward the medium supporting member, and the print head is configured to reciprocate across a width of the medium supporting member. The ink receiving chamber is configured to receive residual ink ejected from the nozzles when the print head is in the first position, and the maintenance device further includes a liquid injection member configured to inject liquid into the ink receiving chamber when the print head is away from the first position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention and many of the attendant advantages thereof will become readily apparent with reference to the following detailed description, particularly when considered in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view showing a printer according to an embodiment of the present invention; 
         FIG. 2  is a side view showing a print head and a maintenance device according to an embodiment of the invention; 
         FIG. 3  is a plan view showing the maintenance device and the print head; 
         FIG. 4  is a plan view showing the maintenance device and the print head; 
         FIG. 5  is a plan view showing the maintenance device and the print head in a standby position; 
         FIG. 6  is a plan view showing the maintenance device; and 
         FIG. 7  is a flow chart showing the actions of the maintenance device and the print head. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. In the following description, the constituent elements having substantially the same function and arrangement are denoted by the same reference numerals, and repetitive descriptions will be made only when necessary. 
     As noted above, problems associated with related art waste liquid tank configurations have been identified. For example, when a tube or the like is used to send the residual ink received by the ink receiving chamber to the waste liquid tank, the ink can become solidified inside the tube and the tube can become clogged according to the inner diameter and the length of the tube, so that it is difficult to send the residual ink to the waste liquid tank. 
     According to an aspect of the invention, the present invention addresses the aforementioned problem. 
     The present invention generally relates to a printer for printing on a print medium by ejecting ink droplets on the print medium. According to an aspect of the invention, a printer is provided having a maintenance device that is placed near an end of the printer for performing maintenance for nozzles, and in which residual ink received by an ink receiving chamber can be sent to the waste liquid tank without solidification of the ink. 
     In an embodiment of the invention, a printer is provided that includes: a medium supporting member which supports a print medium, having a predetermined width in the left-right direction, in a state placed thereon; a print head which is disposed to face the medium supporting member in the vertical direction, has nozzles for ejecting ink droplets downward, and freely reciprocates above the medium supporting member in the width direction; and a maintenance device which is disposed to face a lower surface of the print head when the print head is in a position at one end of its reciprocating movement and receives residual ink in the nozzles which is ejected from the nozzles when the print head is in the position at one end of its reciprocating movement. The printer conducts intended printing on the print medium by ejecting printing ink droplets from the nozzles to the print medium with reciprocating the print head. The maintenance device has an ink receiving chamber which opens upward to receive the residual ink ejected from the nozzles, and a liquid injection member which injects liquid into the ink receiving chamber when the print head is away from a position where the print head faces the ink receiving chamber in the vertical direction. 
     In a printer having the aforementioned structure, it is preferable that the maintenance device has an evacuating means which evacuates the liquid injection member, placed above the ink receiving chamber, out of the position above the ink receiving member when the print head moves to the one end of its reciprocating movement. 
     According to such an embodiment, since the maintenance device has the liquid injection member for injecting liquid into the ink receiving chamber so that the residual ink and the injected liquid are mixed in the ink receiving chamber, the concentration of the residual ink in the ink receiving chamber can be reduced so that the residual ink is hardly solidified, and the viscosity of the residual ink is lowered so that the residual ink easily flows, thereby facilitating the residual ink discharging outside from the ink receiving chamber. 
     Furthermore, since the maintenance device preferably has an evacuating means for evacuating the liquid injection member from the position above the ink receiving chamber when the print head is returned from the position above the medium supporting member to the standby position. Accordingly, when the residual ink is ejected from the nozzles while the print head is in the standby position, the residual ink ejected is not interfered with the liquid injection member and is thus prevented from scattering, thereby further ensuring the receiving of the residual ink by the ink receiving chamber. Further, the liquid injection member is therefore prevented from being contaminated with the residual ink, thereby decreasing the frequency of cleaning of the maintenance device and thus improving the workability of the printer. Furthermore, even when the liquid injection member and the lower surface of the print head are placed at positions of interfering with each other in the vertical direction, the liquid injection member is evacuated out of the area where the print head passes by the evacuating means and is not interfered with the print head, thereby achieving safe operation of the printer. Moreover, the liquid injection member and the lower surface of the print head can be designed to have a smaller distance therebetween in the vertical direction, thereby enabling the reduction in size of the printer. 
     Hereinafter, a preferred embodiment of a printer  1  according to the present invention will be described with reference to  FIG. 1  through  FIG. 7 . For ease of explanation, leftward (left), rightward (right), forward (front), backward (rear), upward and downward directions (sometime referred to as a vertical direction) are defined by the directions of arrows shown in  FIG. 1 . 
     As shown in  FIG. 1 , the printer  1  is a printing apparatus for printing by ejecting liquid ink droplets to a sheet-like print medium  2 , which is carried in a state wound into a roll. The printer  1  includes a printing section  10  for conducting the printing process which is disposed in an upper portion of the printer  1 , and a retaining section  50  which is disposed in a lower portion of the printer  1 . 
     The printing section  10  mainly includes a left storage housing  11 , a right storage housing  12 , a print head  13 , a guide rail  14 , a holding member  15 , and a platen (or medium supporting member)  16 . The guide rail  14  extends in the left-right direction for a length longer than the width of the print medium  2  such that the left and right ends of the guide rail  14  are housed in the left storage housing  11  and the right storage housing  12 , respectively. The guide rail  14  is provided with grooves that are formed in its front surface to extend in the left-right direction for limiting movement in the forward, backward, upward, and downward directions of the print head  13 . 
     The print head  13  has convexes formed on its rear surface that are slidably engaged with the grooves formed in the front surface of the guide rail  14 , whereby the print head  13  can freely reciprocate in the left-right direction along the guide rail  14 . The print head  13  is provided inside thereof with a plurality of nozzles (not shown), which are arranged to face downward to eject liquid ink droplets, supplied from a plurality of ink cartridges (not shown), to the print medium  2  on the platen  16  so that the nozzles face the print medium  2 . The print head  13  is provided with a slide projection  13   a  (see  FIGS. 2-5 ), which projects rightward from the right surface of the print head  13  and has a substantially triangular shape, as seen from above as shown in  FIG. 3 , and has a predetermined width in the vertical direction. Formed on the rear surface of the slide projection  13   a  is a slide slant face  13   b , which is inclined from the left rear side to the right front side. The slide slant face  13   b  is adapted to come in contact with a contact column  32 , as will be described later, in the vertical direction. When the print head  13  moves along the guide rail  14  to the right end portion (i.e., the “standby position”), the print head  13  and an ink receiving chamber  35  of a maintenance device  20 , as will be described later, are adapted to face each other in the vertical direction. During printing operation, print ink droplets ejected from the nozzles pass through an ejecting opening  13   c  formed in the lower surface of the print head  13  and adhere to the print medium  2 , thereby conducting the printing. 
     The left storage housing  11  is disposed at an upper left end of the printer  1  and is formed in a box-like shape to cover a left end portion of the guide rail  14 . The right storage housing  12  is disposed at an upper right end of the printer  1  and is formed in a box-like shape to cover a right end portion of the guide rail  14 . Placed inside the right storage housing  12  is the maintenance device  20 . Installed in the left storage housing  11  and the right storage housing  12  are, for example, an operation panel for operating the printer  1  and ink cartridges in which ink to be ejected from the nozzles is stored, but not shown. 
     The platen  16  extends in the left-right direction for a length longer than the width of the print medium  2  and is disposed below the print head  13 . As shown in  FIG. 1 , the platen  16  has slant surfaces at its both ends in the forward-backward direction so as to facilitate the feeding and discharging of the print medium  2  and has a surface facing the print head  13 , which is parallel with the lower surface of the print head  13 . The holding member  15  extends in the left-right direction for a length longer than the width of the print medium  2  and is disposed below the guide rail  14 . The holding member  15  is positioned at the back of the print head  13  and has a rotational roller (not shown) that is at the lower end of the holding member  15  to come in contact with the print medium  2 . In addition, the holding member  15  is arranged movably in the vertical direction. Therefore, the holding member  15  moves downward so that the rotational roller presses the print medium  2  on the platen  16  from above, thereby regulating the movement of the print medium  2  in the feeding direction (shown by an arrow in  FIG. 1 ). 
     As shown in  FIGS. 1 and 2 , the maintenance device  20  mainly includes a cleaning solution cartridge  21 , a supporting container  30 , a swing member  33 , an ink receiving chamber  35 , a wiper  38 , a drainage pump  40 , and a waste liquid tank  43 . The cleaning solution cartridge  21  is a cartridge containing cleaning solution, which is soluble in residual ink so as to decrease the concentration of the residual ink collected in the ink receiving chamber  35 . The cleaning solution cartridge  21  is placed on the upper surface of the right storage housing  12 . Further, the cleaning solution cartridge  21  is in communication with an end of a cleaning solution passage  23 , which is, for example, a flexible tube made of a resin material. A control valve  22  is disposed near the upper end of the cleaning solution passage  23  to control the dropping of the cleaning solution by gravity from the cleaning solution cartridge  21 . 
     The supporting container  30  is disposed inside the right storage housing  12  as shown in  FIG. 1  and includes a supporting box  30   a , which is made of, for example, a resin material to have a box-like shape that opens at its upper surface, and a supporting base  30   b , which is made of, for example, a metallic material to have a plate-like shape that is disposed on a rear edge of the upper opening of the supporting box  30   a  and extends rearward. The supporting container  30  is disposed at such a vertical position that the upper opening does not interfere with the lower surface of the print head  13 . In addition, the supporting base  30   b  has a cutout formed in a front portion of a right side and has a rear edge portion  30   c  at the rear end of the cutout. 
     The swing member  33  is made of, for example, a resin material to have a plate-like shape extending in the left-right direction, and has a rod-like return projection  33   a  extending in the right direction from the right surface of the swing member  33  as shown in  FIG. 3 . One end of a spring  33   b  is fixed to the right end of the return projection  33   a  and the other end of the spring  33   b  is fixed to the rear edge portion  30   c . In the state the swing member  33  is mounted on the upper surface of the supporting base  30   b , the supporting base  30   b  and the right end portion of the swing member  33  are connected by a pivot pin  31  so that the swing member  33  can freely swing in the forward-backward direction about the pivot pin  31 . That is, as the swing member  33  is moved to swing rearward and then force of holding the swing member  33  in this state is removed, the swing member  33  returns to the position shown in  FIG. 3  by spring force of the spring  33   b . The swing member  33  is provided with the contact column  32  at a position about the center in the left-right direction of the swing member  33 . The contact column  32  is formed in a column-like shape extending upward from the upper surface of the swing member  33 . 
     Fixed to the upper surface of the swing member  33  is an end of a fixing member  34 , which is formed in a plate shape, for example. On the other hand, at the other end of the fixing member  34 , one end of an injection pipe (or liquid injection member)  24 , which is made of a metal to have a tube-like shape and which is bent into substantially a V-like shape, is held by the fixing member  34  and is in communication with the lower end of the aforementioned cleaning solution passage  23 . When the print head  13  is not in the standby position, an injection port  24   a  of the other end of the injection pipe  24  is adapted to be positioned near the center of the ink receiving chamber  35  as seen from above as shown in  FIG. 6 . The injection pipe  24  is placed below the lower surface of the print head  13  in the vertical direction not to interfere with the lower surface of the print head  13  as shown in  FIG. 2 . 
     The ink receiving chamber  35  is made of, for example, a resin material. As shown in  FIG. 2 , the ink receiving member  35  is formed in substantially a rectangular parallelepiped, which opens at its upper surface and is hollow, and is disposed inside the supporting box  30   a  such that the height of the upper opening of the ink receiving chamber  35  and the height of the upper opening of the supporting box  30   a  are substantially equal. Filled in the hollow portion inside the ink receiving chamber  35  is a porous absorbing member  36 . Fixed to the ink receiving chamber  35  to cover the upper opening of the ink receiving chamber  35  is an upper frame  37  which is made of a metal to have a net-like structure such that the upper frame  37  is disposed on the absorbing member  36  from above. The upper frame  37  holds the absorbing member  36  not to project upward from the upper opening. 
     The wiper  38  is made of, for example, a resin material to have a plate-like shape extending in the forward-backward direction and is disposed at a vertical position capable of coming into contact with the lower surface of the print head  13 . The wiper  38  is connected at its lower portion to a wiper driving member  38   a , which is arranged inside the supporting box  30   a . By the wiper driving member  38   a , the wiper  38  can be reciprocated in the forward-backward direction as shown in  FIG. 3 . When the wiper  38  is moved to the rear side, the upper end of the wiper  38  can come in contact with the ejecting opening  13   c.    
     A drainage pump  40  is a device for forcing liquid to enter or discharge by operation of the drainage pump  40  and is disposed inside the printer  1 . As shown in  FIG. 2 , one end of a first discharge passage  41 , which is made of, for example, a resin material to have a tube-like shape, is in communication with the opening formed in the bottom of the ink receiving chamber  35 , and the other end of the first discharge passage  41  is in communication with the suction port of the drainage pump  40 . On the other hand, one end of a second discharge passage  42 , which is made of, for example, a resin material to have a tube-like shape, is in communication with the waste liquid tank  43 , and the discharge port of the drainage pump  40  is in communication with the other end of the discharge passage  42 . The waste liquid tank  43  is a tank having a hollow portion inside thereof and has an upper end in communication with the one end of the second discharge passage  42  so that liquid can enter into the waste liquid tank  43  through the second discharge passage  42  and can be stored in the waste liquid tank  43 . 
     As shown in  FIG. 1 , the retaining section  50  mainly includes a base  51 , supporting members  52 , guide supporting arms  53 , a first guide member  54 , a sheet supplying member  60 , fixing arms  70 , and a second guide member  71 . Further, the retaining section  50  has the same structure on the rear side as that on the front side. That is, the retaining section  50  has a sheet winding member (not shown) provided in a symmetrical position in the forward-backward direction to the sheet supplying member  60  on the front side. Therefore, explanation about the rear side of the retaining section  50  will be omitted. 
     The base  51  is formed substantially in a rectangular parallelepiped extending in the left-right direction for a length longer than the width of the print medium  2  to support the printing section  10 , which is arranged above the base  51 . The supporting members  52  are each formed substantially in a rectangular parallelepiped extending in the forward direction and the rear ends of the supporting members  52  are fixed to the base  51  at lower portions near the left and right ends of the base  51 , respectively. The fixing arms  70  are each formed in a plate shape extending in the forward direction and the rear ends of the fixing arms  70  are fixed to the base  51  at portions substantially the same as the supporting members  52  in the left-right direction and above the supporting members  52 . 
     As shown in  FIG. 1 , the first guide member  54  is made of, for example, a metallic material to have a cylindrical shape extending in the left-right direction for a length longer than the width of the print medium  2 . Both ends of the guide member  54  in the left-right direction are rotatably supported by the front ends of the guide supporting arms  53 . On the other hand, the rear ends of the guide supporting arms  53  are rotatably supported by the supporting members  52 . According to this structure, the guide supporting arms  53  and the first guide member  54  can pivotally move in the vertical direction about the rear ends of the guide supporting arms  53 . 
     The sheet supplying member  60  has a sheet supplying shaft  61  extending in the left-right direction onto which the unprinted print medium  2  is wound. The ends in the left-right direction of the sheet supplying shaft  61  are rotatably supported by the supporting members  52 . At the portions of the sheet supplying shaft  61  supported by the supporting members  52 , it is configured to apply rotational force to the sheet supplying shaft  61  and to brake the sheet supplying shaft  61  to prevent the sheet supplying shaft  61  from freely rotating. 
     The sheet winding member disposed on the rear surface of the base  51  includes a sheet winding shaft (not shown) extending in the left-right direction onto which the print medium  2  that has been printed upon is wound. The ends in the left-right direction of the sheet winding shaft are rotatably supported by supporting members (not shown). Similarly to the sheet supplying member  60  as mentioned above, at the portions of the sheet winding shaft supported by the supporting members, it is configured to apply rotational force to the sheet winding shaft and to brake the sheet winding shaft to prevent the sheet winding shaft from freely rotating. 
     The second guide member  71  is made of, for example, a metallic material to have a cylindrical shape extending in the left-right direction for a length longer than the width of the print medium  2  and has a smooth peripheral surface. The second guide member  71  is held and fixed at both ends thereof by the fixing arms  70  and the fixing arms  70  are disposed on the front surface of the base  51  so that the second guide member  71  can smoothly introduce the print medium  2  to the slant surface at the front end of the platen  16 . 
     The structure of the inkjet printer  1  has been described above. Hereinafter, the actions of the print head  13  and the maintenance device  20  will be described with reference to a flow chart shown in  FIG. 7 . 
     First, in step S 1 , as shown in  FIG. 5 , the print head  13  is in the standby position at the right end of the guide rail  14 . In this state, the contact column  32  comes in contact with the slide slant face  13   b  so that the swing member  33  swings backward together with the injection pipe  24  and the fixing member  34  about the pivot pin  31 . Accordingly, the injection pipe  24  is evacuated to a position apart from the upper surface of the ink receiving chamber  35 , while the ejecting opening  13   c  and the upper opening of the ink receiving chamber  35  are substantially overlapped as seen from the above. The return projection  33   a  swings forward about the pivot pin  31  so that the spring  33   b  is drawn forward and thus stores its biasing force. The wiper  38  is in a forward position as shown by solid lines. In this position, the wiper  38  is never in contact with the ejecting opening  13   c  even when the print head  13  moves leftward along the guide rail  14 . 
     In step S 2 , in the state shown in  FIG. 5 , residual ink staying in the end portions of the nozzles are ejected to the ink receiving chamber  35  and is thus discharged. During this time, since the ejecting opening  13   c  and the upper opening of the ink receiving chamber  35  are substantially overlapped and the injection pipe  24  is evacuated from the upper surface of the ink receiving chamber  35  as mentioned above, the residual ink ejected is surely received by the ink receiving chamber  35 . The discharged residual ink interpenetrates into the absorbing member  36 , then flows downward in the ink receiving chamber  35 , and becomes deposited on the bottom of the ink receiving chamber  35 . 
     Then, the procedure proceeds to step S 3 . As shown in  FIG. 5 , the wiper  38  is moved to a position  38   b  shown by a two-dot chain line by the wiper driving member  38   a . In this state, since the wiper  38   b  is in the position  38   b , the ejecting opening  13   c  comes in contact with the end portion of the wiper  38  when the print head  13  moves leftward along the guide rail  14 . 
     Then, in step S 4 , the print head  13  is moved leftward along the guide rail  14  from the standby position to start printing. During this, since the wiper  38  is in the position  38   b  shown by the two-dot chain line as shown in  FIG. 5 , the print head  13  is moved with its ejecting opening  13   c  coming in contact with the end of the wiper  38  whereby the residual ink adhering to portions around the ejecting opening  13   c  is wiped by the wiper  38 . Therefore, printing ink ejected from the ejecting opening  13   c  is prevented from being mixed with residual ink, thereby improving the printing accuracy during printing. 
     Also in step S 4 , while the print head  13  is moved leftward from the standby position along the guide rail  14 , the contact column  32 , which is in contact with the slide slant face  13   b  because the contact column  32  is biased forward by the biasing force of the spring  33   b , moves forward with keeping the contact state according to the slide slant face  13   b , whereby the swing member  33  swings forward about the pivot pin  31  together with the injection pipe  24  and the fixing member  34 . After that, as the print head  13  is moved leftward to such a position that the slide slant face  13   b  and the contact column  32  are not in contact with each other, the injection port  24   a  is positioned near the center of the upper opening of the ink receiving chamber  35  (see  FIG. 3 ). The wiper  38  wipes the residual ink on the ejecting opening  13   c  while the print head  13  passes through above the wiper  38 . After that, the wiper  38  is returned to the position  38  shown by the solid line by the wiper driving member  38   a . The print head  13  moved to the position above the platen  16  is reciprocated in the left-right direction above the platen  16  and ejects printing ink droplets from the nozzles toward the print medium  2  while the print medium  2  is fed in the feeding direction, thereby conducting intended printing. 
     Then, the procedure proceeds to step S 5 . While the print head  13  conducts printing on the print medium  2 , in the maintenance device  20  in the state shown in  FIG. 6 , first the control valve  22  is opened for a certain period of time, the cleaning solution flows by gravity from the cleaning solution cartridge  21  through the cleaning solution passage  23  to the injection pipe  24  and is then injected from the injection port  24   a  to a portion about the center of the upper opening of the ink receiving chamber  35 . In this state, by opening the control valve  22  and driving the drainage pump  40  for a certain period of time, the residual ink and the cleaning solution deposited on the bottom of the ink receiving chamber  35  are forced to flow from a first discharge passage  41  to the drainage pump  40  and, after that, are forced to be discharged from the drainage pump  40  to the waste liquid tank  43  through a second discharge passage  42 . It should be noted that the injection of the cleaning solution from the injection port  24   a  and the driving of the drainage pump  40  are terminated before proceeding to next step S 6 . 
     Then, in step S 6 , after printing on the print medium  2  for a certain period of time, the print head  13  is returned to the standby position at the right end. At this point, the state around the right end is moved from the state shown in  FIG. 3  to the state shown in  FIG. 4  and is further moved from the state shown in  FIG. 4  to the state shown in  FIG. 5  (standby position). This movement will be described step by step. First, the print head  13  is moved from the left side to the right side of the supporting container  30  toward the standby position as shown in  FIG. 3 . After that, the print head  13  is moved further from the state shown in  FIG. 3  so that the slide slant face  13   b  comes in contact with the contact column  32 . As the print head  13  is moved rightward further from this state, the contact column  32  is moved backward along the slide slant face  13   b  and the swing member  33  with the injection pipe  24  and the fixing member  34  swings backward about the pivot pin  31  as shown in  FIG. 4 . During this, the return projection  33   a  swings forward about the pivot pin  31  to stretch the spring  33   b . After that, the print head  13  is further moved rightward and is therefore returned to the standby position shown in  FIG. 5 . In this state, the ejecting opening  13   c  and the upper opening of the ink receiving chamber  35  are substantially overlapped as seen from above. Since the detail of this state has been described above, explanation of this state will be omitted. 
     Then, the procedure proceeds to step S 7 . When it is determined that there is still a region where printing should be provided, the procedure returns to step S 2 . Until it is determined that all printing on the print medium  2  is completed, step S 2  through step S 6  are repeated. On the other hand, when it is determined that all printing on the print medium  2  is completed, the flow chart is terminated. 
     Hereinafter, the effects of the printer  1  according to the present invention will be summarized. First, by injecting cleaning solution into the ink receiving chamber  35 , the concentration of the residual ink received by the ink receiving chamber  35  is reduced, thereby preventing the ink from being solidified inside the first discharge passage  41  and the second discharge passage  42  and ensuring the residual ink to be discharged outside from the ink receiving chamber  35 . Since the concentration of the residual ink received by the ink receiving chamber  35  can be reduced, the ink is not solidified even when the first discharge passage  41  and the second discharge passage  42  are composed of piping materials having smaller diameter. Therefore, it is possible to reduce the manufacturing cost of the printer  1 . 
     Secondly, the cleaning solution is injected to the center of the ink receiving chamber  35  using the injection pipe  24  so that the cleaning solution uniformly interpenetrates inside the ink receiving chamber  35 , thereby reducing the concentration of the entire residual ink inside the ink receiving chamber  35 . Therefore, the residual ink is prevented from being solidified inside the ink receiving chamber  35 , thereby decreasing the frequency of cleaning of the ink receiving chamber  35  and improving the workability of the printer  1 . 
     Thirdly, the slide projection  13   a  and the contact column  32  come in contact with each other when the print head  13  is in the standby position so as to move the swing member  33 , whereby the injection pipe  24  is evacuated from the upper surface of the ink receiving chamber  35 . Therefore, the evacuation of the injection pipe  24  is achieved by a reasonable and easy method without using, for example, a sensor, thereby reducing the manufacturing cost of the printer  1 . Further, since the swing member  33  moved is adapted to be returned to the original position by the spring  33   b , the swing member  33  can be returned to the original position by a reasonable and easy method without using, for example, a motor, thereby reducing the manufacturing cost of the printer  1 . 
     In the aforementioned embodiment, the opening time period of the control valve  22  and the driving time period of the drainage pump  40  in step S 5  may be freely set. However, it is preferable that the opening time period of the control valve  22  is set such that the cleaning solution can uniformly interpenetrate into the absorbing member  36  and the driving time period of the drainage pump  40  is set such that the residual ink and the cleaning solution deposited on the bottom of the ink receiving chamber  35  can be discharged to the waste liquid tank  43  without remaining inside the first discharge passage  41  and the second discharge passage  42 . 
     Though the injection pipe  24  is evacuated from (or moved away from) the upper surface of the ink receiving chamber  35  by the swing action of the swing member  33 , which is caused by the contact between the slide projection  13   a  and the contact column  32  in the aforementioned embodiment, means for evacuating the injection pipe  24  (or means for moving the injection pipe  24  away) from the upper surface of the ink receiving chamber  35  is not limited to that of the aforementioned embodiment. 
     Though the wiper  38  is adapted not to come in contact with the ejecting opening  13   c  when the print head  13  is returned to the standby position after printing for a certain period of time in the aforementioned embodiment, the wiper  38  can be adapted to come in contact with the ejecting opening  13   c  even when the print head  13  is returned to the standby position similarly to the case that the print head  13  is moved from the standby position to the position above the platen  16 . 
     In the aforementioned embodiment, the lower surface of the print head  13  and the injection pipe  24  are adapted not to interfere with each other in the vertical direction. On the other hand, even when the lower surface of the print head  13  and the injection pipe  24  are adapted to interfere with each other, the interference between the injection pipe  24  and the print head  13  can be prevented by such an arrangement that the injection pipe  24  is evacuated completely out of the area where the print head  13  passes by an evacuating means. Therefore, in this case, the injection pipe  24  according to the present invention can be provided at a position above the ink receiving chamber  35 . 
     It should be noted that the exemplary embodiments depicted and described herein set forth the preferred embodiments of the present invention, and are not meant to limit the scope of the claims hereto in any way. Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.