Abstract:
A fluid ejection apparatus ejects a fluid from a nozzle and includes a nozzle opening surface in which the nozzle is formed. A fluid removal unit removes fluid adhering to the nozzle opening surface. The fluid removal unit includes a plate-shaped wiper member that is formed from an elastic material. The wiper member moves from one end of the nozzle opening surface to the other as the ejection head or the wiper member moves while in a state where the wiper member makes contact with the nozzle opening surface and elastically deforms. A splash catching member is erected in front of the wiper member when the wiper member moving relative along the nozzle opening surface separates from the nozzle opening surface and returns to its original shape. The splash catching member catches objects that had been adhering to the nozzle opening surface and are scattered by the wiper member.

Description:
[0001]    This application claims the benefit of Japanese Patent Application No. 2009-033593, filed Feb. 17, 2009, which is expressly incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a technique for ejecting a fluid onto an ejection target medium. 
         [0004]    2. Related Art 
         [0005]    Ink jet printers print images by ejecting ink onto a print medium. Because the locations in which ink is ejected, the ejection amount, and so on can be controlled with an extremely high level of precision, high-quality images can be printed. Fluid ejection apparatuses that form various types of functional components, such as electrodes, sensors, and the like, by ejecting fluids containing various types of functional materials onto a substrate have also been proposed. 
         [0006]    Fluid ejection apparatuses such as ink jet printers and the like include an ejection head provided with multiple nozzles, and eject a fluid such as ink onto an ejection target medium (for example, a print sheet) by ejecting the fluid from the nozzles while changing the relative position between the ejection head and the ejection target medium. If a foreign object adheres to a nozzle opening surface formed in the ejection head in a position facing the ejection target medium, there is a risk that the foreign object will obstruct the ejection of the fluid. Accordingly, the stable ejection of the fluid is facilitated by using a plate-shaped member formed from an elastic material such as silicon rubber (a wiper member) to remove the foreign object that has adhered to the nozzle opening surface. Note that the operation for using such a wiper member to remove objects adhering to the nozzle opening surface is called “wiping”. 
         [0007]    During wiping, the wiper member is in an elastically deformed state due to the nozzle opening surface. The elastically deformed wiper member thus forcefully attempts to return to its original shape after the wiping has ended, and if the objects that adhered to the nozzle opening surface and were removed are scattered as a result, there is a risk that the surrounding area will be soiled thereby. Accordingly, a technique that attempts to avoid soiling the surrounding area by suppressing the force with which the wiper member returns to its original shape has been proposed (JP-A-07-032611). 
         [0008]    However, there is a problem with the stated proposed technique in that soiling the surrounding area due to the objects that adhered to the nozzle opening surface being scattered during removal cannot be completely avoided. That is, even if the force with which the wiper member returns to its original shape is suppressed, the wiper member nevertheless attempts to return under its own elastic force, and thus the objects that adhered to the nozzle opening surface may still be scattered at that time. Accordingly, there is a problem in that a situation in which the surrounding area is soiled by adhering objects that have been scattered cannot be completely prevented. 
       SUMMARY 
       [0009]    An advantage of some aspects of the invention is to provide a technique that enables the complete elimination of the risk that a surrounding area will be soiled by scattered adhering objects that were removed from a nozzle opening surface by the wiper member. 
         [0010]    In order to solve at least part of the problem mentioned above, a fluid ejection apparatus according to an aspect of the invention adopts the following configuration. That is, the apparatus is a fluid ejection apparatus that ejects a fluid from a nozzle provided in an ejection head, and includes: a nozzle opening surface in which the nozzle is provided; and a fluid removal unit that removes fluid adhering to the nozzle opening surface. The fluid removal unit has: an approximately plate-shaped wiper member formed from an elastic material; a relative movement unit that causes the wiper member to move relative to the nozzle opening surface from one end of the nozzle opening surface to the other end of the nozzle opening surface by causing at least one of the ejection head and the wiper member to move while in a state where the wiper member makes contact with the nozzle opening surface and elastically deforms; and a splash catching member, having an approximate plate shape, that is erected in front of the wiper member when the wiper member moving relative along the nozzle opening surface separates from the nozzle opening surface and returns to its original shape, the splash catching member catching objects that had been adhering to the nozzle opening surface and that are scattered by the wiper member. 
         [0011]    With the fluid ejection apparatus according to this aspect of the invention, at least one of the ejection head and the wiper member is caused to move while in a state where the wiper member makes contact with the nozzle opening surface, and thus it is possible to remove objects that have adhered to the nozzle opening surface. In addition, when the wiper member separates from the nozzle opening surface and returns to its original shape, the approximately plate-shaped splash catching member is erected in front of the wiper member (in a direction in which the wiper member relatively moves to reach a point for separating from the nozzle opening surface); accordingly, even if objects that had been adhering to the nozzle opening surface are scattered from the wiper member, those objects can be caught. 
         [0012]    In order to effectively remove objects that adhere to the nozzle opening surface, it is necessary to bring the wiper member into contact with the nozzle opening surface and cause the wiper member to deform. As a result, when the wiper member separates from the nozzle opening surface, the wiper member will inevitably return to its original shape. As long as the wiper member returning to its original shape is inevitable, it is extremely difficult to completely prevent the wiper member from scattering objects adhering thereto at that time. However, if the objects scattered by the wiper member are caught instead, erecting the splash catching member in front of the wiper member makes it possible to catch the entirety of the splash. Accordingly, it is possible to easily and completely prevent the surrounding area from being soiled by objects removed from the nozzle opening surface and scattered by the wiper member. 
         [0013]    In addition, according to another aspect of the invention, the splash catching member in the fluid ejecting apparatus may be provided in a position adjacent to the wiper member. The splash catching member may enter a withdrawn state in which the splash catching member does not interfere with the nozzle opening surface in a stage before the wiper member makes contact with the nozzle opening surface, and may then return to the erect state in front of the wiper member in a stage before the wiper member separates from the nozzle opening surface. 
         [0014]    Providing the splash catching member adjacent to the wiper member in this manner makes it possible to process the objects caught by the splash catching member collectively along with the objects removed by the wiper member. 
         [0015]    According to another aspect of the invention, the fluid ejection apparatus may be configured as follows. First, the splash catching member is configured of a retractable member. The splash catching member may enter the state in which it is withdrawn from the nozzle opening surface by tilting upon making contact with the ejection head before the wiper member makes contact with the ejection head, and may then return to the erect state in front of the wiper member by separating from the ejection head before the wiper member separates from the nozzle opening surface. 
         [0016]    If an attempt is made to withdraw the splash catching member by sliding the splash catching member when withdrawing the splash catching member to a position in which it does not interfere with the nozzle opening surface, an actuator that drives the splash catching member is required to perform a stroke having the same amount of movement as the splash catching member. As opposed to this, if the splash catching member is withdrawn by tilting the splash catching member, the tip portion of the splash catching member experiences a large amount of movement even if the splash catching member is withdrawn by only a small rotational angle. Accordingly, tilting the splash catching member rather than sliding the splash catching member makes it easier to withdraw the splash catching member to a position in which the splash catching member does not interfere with the nozzle opening surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
           [0018]      FIG. 1  is a descriptive diagram illustrating the general configuration of a fluid ejection apparatus according to an embodiment of the invention, using an ink jet printer as an example. 
           [0019]      FIG. 2  is a perspective view illustrating a carriage case from the bottom surface thereof. 
           [0020]      FIG. 3  is a perspective view illustrating the external shape of a wiping mechanism according to an embodiment of the invention. 
           [0021]      FIG. 4  is an exploded view of an ink guard and guide cams. 
           [0022]      FIGS. 5A to 5E  are descriptive diagrams illustrating a wiping operation performed by a wiping mechanism according to an embodiment of the invention. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0023]    Hereinafter, an embodiment of the invention will be described according to the following order in order to clarify the content of the invention. 
         [0024]    A. Apparatus Configuration 
         [0025]    B. Wiping Mechanism 
       A. Apparatus Configuration 
       [0026]      FIG. 1  is a descriptive diagram illustrating the general configuration of a fluid ejection apparatus according to an embodiment of the invention, using what is known as an ink jet printer as an example. As shown in  FIG. 1 , an ink jet printer  10  is configured of: a carriage  20  that forms ink dots upon a print medium  2  while moving back and forth in the main scanning direction; a driving mechanism  30  that moves the carriage  20  back and forth; a paper transport roller  40  for transporting the print medium  2 ; a cap  50  in which a rubber material is formed in a concave shape; a wiping mechanism  60  for removing foreign objects such as ink that have adhered to the bottom surface of the carriage  20  (the side of the carriage  20  that faces the print medium  2 ); and so on. 
         [0027]    Of these, the carriage  20  is provided with an ink cartridge  28  that holds ink, a carriage case  22  in which the ink cartridge  28  is installed, and so on, and an ejection head  24  for ejecting ink droplets is provided on the bottom surface of the carriage case  22 . The ink within the ink cartridge  28  is supplied to the ejection head  24 , and an appropriate amount thereof is ejected onto the print medium  2 . Furthermore, guide rails  26 , mentioned later, that protrude on both sides of the ejection head  24  are provided on the bottom surface of the carriage case  22 . The guide rails  26  will be described later with reference to another drawing. 
         [0028]    The ejection head  24  is provided with multiple nozzles for ejecting ink, but if foreign objects such as ink, dust, or the like adhere to a nozzle opening surface into which these nozzles open, the ink cannot be ejected in an appropriate manner. Accordingly, a wiping operation for wiping off foreign objects that have adhered to the nozzle opening surface is carried out by causing one of a wiper blade formed from an elastic material such as silicon rubber and the ejection head  24  to move relative to the other in a state in which the wiper blade is pressed against the nozzle opening surface. The wiping mechanism  60  is a mechanism for performing such a wiping operation. Meanwhile, if the wiper blade that is pressed against the nozzle opening surface returns to its original shape after the wiping operation has ended and scatters the foreign objects, such as ink, that have been wiped off of the nozzle opening surface, the surrounding area will be soiled. Accordingly, the wiping mechanism  60  according to this embodiment is provided with an ink guard (a splash catching member) for preventing foreign objects from the wiper blade from scattering into the surrounding area. The specific structure of the wiping mechanism  60  and the action by which foreign objects scattered by the wiper blade are guarded against will be described in detail later. 
         [0029]    Meanwhile, the paper transport roller  40  is driven by a driving motor, a gear mechanism, and so on (not shown), and is capable of transporting the print medium  2  in the sub-scanning direction in predetermined increments. 
         [0030]      FIG. 2  is a perspective view illustrating the carriage case  22  from the bottom surface thereof. As shown in  FIG. 2 , the ejection head  24  is provided on the bottom surface of the carriage case  22 , and multiple small nozzles for ejecting ink are open on the surface of the ejection head  24  that faces the print medium  2 . These nozzles are provided in a state in which they are grouped by the color of the ink they eject. With the ink jet printer  10  according to this embodiment, four colors of ink, or black ink (K ink), cyan ink (C ink), magenta ink (M ink), and yellow ink (Y ink), are installed, and the nozzles are provided in a state in which they are roughly divided into four groups, or a nozzle group that ejects K ink, a nozzle group that ejects C ink, a nozzle group that ejects M ink, and a nozzle group that ejects Y ink. A nozzle opening surface  25  is formed for each of these nozzle groups. 
         [0031]    Meanwhile, as shown in  FIG. 2 , plate-shaped guide rails  26  protrude on both sides of the ejection head  24 . Although details will be provided later, with the ink jet printer  10  according to this embodiment, the ink guard is driven by using these guide rails  26  to partially depress the wiping mechanism  60 . Hereinafter, the structure of the wiping mechanism  60  and operations of the wiping mechanism  60  according to this embodiment will be described in detail. 
       B. Wiping Mechanism 
       [0032]      FIG. 3  is a perspective view illustrating the external shape of the wiping mechanism  60  provided in the ink jet printer  10  according to this embodiment. As shown in  FIG. 3 , the wiping mechanism  60  according to this embodiment is configured of an approximately plate-shaped wiper blade  62 , and approximately plate-shaped ink guard  64  provided approximately parallel to the wiper blade  62 , a pair of guide cams  66  provided so as to sandwich the wiper blade  62  and the ink guard  64  on both sides thereof, and so on. Of these, the pair of guide cams  66  and the ink guard  64  are linked to each other, and the configuration is such that the ink guard  64  moves in correspondence with movement in which the guide cams  66  are depressed by the aforementioned guide rails  26 . As opposed to this, the wiper blade  62  and the guide cams  66  do not move in correspondence with each other, and thus even if the guide cams  66  are depressed, the wiper blade  62  does not move as a result thereof. Furthermore, as shown in  FIG. 3 , the cap  50  is, when viewed from the wiper blade  62 , provided on the far side of the ink guard  64 , so that the ink guard  64  is located between the wiper blade  62  and the cap  50 . In addition, the ink guard  64  is formed so as to be larger than the wiper blade  62  in terms of both width and height. 
         [0033]      FIG. 4  is an exploded view of the ink guard  64  and the guide cams  66 . The wiper blade  62  has been omitted from  FIG. 4  in order to avoid complicating the drawing. As shown in  FIG. 4 , a shaft is formed in the bottom side of the ink guard  64 , which is formed approximately as a plate shape, and small pinion gears  64   p  are fitted onto both sides of the shaft; thus the ink guard  64  and the pinion gears  64   p  are formed as a single integral component. Meanwhile, a thin shaft  66   s  is provided parallel to the shaft in the bottom side of the ink guard  64 , and the pair of guide cams  66  is attached so as to sandwich the ink guard  64  and the shaft  66   s.  Furthermore, as shown in  FIG. 4 , a rack  66   r  is formed on the inner side of each guide cam  66 , and what is known as a rack and pinion mechanism is thus configured by engaging the rack  66   r  with the pinion gears  64   p  of the ink guard  64 . 
         [0034]    Meanwhile, a cam surface is formed on the upper surface of the guide cams  66 . When the cam surface is pushed by the guide rails  26  provided in the ejection head  24 , the guide cams  66  rotate about the shaft  66   s  functioning as the rotational axis, and that movement is transmitted to the rack and pinion mechanism, causing the ink guard  64  to rotate and fall. Meanwhile, springs and stoppers (not shown) are also provided in the guide cams  66 . Accordingly, the guide cams  66  are in the state shown in  FIG. 3  when not being pressed by the guide rails  26 , and rotate about the shaft  66   s  only when being depressed by the guide rails  26 . Note that the wiper blade  62  is provided in the space between the shaft  66   s  and the ink guard  64 , as shown in  FIG. 3 . Hereinafter, an operation by which the wiping mechanism  60  according to this embodiment, configured as described thus far, wipes away ink or the like that has adhered to the nozzle opening surface  25  of the ejection head  24  will be described. 
         [0035]      FIGS. 5A to 5E  are descriptive diagrams illustrating operations by which the wiping mechanism  60  according to this embodiment wipes away ink or the like that has adhered to the nozzle opening surface  25  of the ejection head  24  (a wiping operation). With the ink jet printer  10  according to this embodiment, the carriage case  22  is capable of moving in the sub scanning direction, but the cap  50 , the wiping mechanism  60 , and so on are in a fixed state. Accordingly, the wiping operation is carried out by moving the carriage case  22  toward the wiping mechanism  60 .  FIG. 5A  illustrates a state in which the carriage case  22  is being moved in order to perform the wiping operation. Here, the guide rails  26  are provided protruding from the bottom surface of the carriage case  22 , as described earlier using  FIG. 2 , and the guide cams  66  are provided in the wiping mechanism  60 , as described earlier using  FIG. 3 . As shown in  FIG. 5A , the guide rails  26  and the guide cams  66  are provided in positions in which they interfere with each other as the carriage case  22  approaches the guide cams  66 . Accordingly, the guide rails  26  provided in the carriage case  22  ultimately depress the guide cams  66 , causing the guide cams  66  to rotate about the shaft  66   s.    
         [0036]      FIG. 5B  illustrates a state in which the guide cams  66  have rotated about the shaft  66   s  as a result of being depressed by the guide rails  26 . As shown in  FIG. 4 , a rack and pinion mechanism is formed between the guide cams  66  and the ink guard  64 , and thus the rotational movement of the guide cams  66  is transmitted to the ink guard  64 , causing the ink guard  64  to rotate so as to slant. The speed reduction ratio of the rack and pinion mechanism is set so that the rotation of the guide cams  66  is transmitted to the pinion gears  64   p  of the ink guard  64  in an accelerated state. Accordingly, the ink guard  64  experiences a large amount of rotation due to even a small amount of rotation by the guide cams  66 , as shown in  FIG. 5B . As a result of the ink guard  64  experiencing such a large amount of rotation, the tip of the ink guard  64  draws away to a position in which it will not interfere with the bottom surface of the ejection head  24 . 
         [0037]    As shown in  FIG. 5C , when the carriage case  22  is moved further with the guide rails  26  still depressing the guide cams  66  (with the tip of the ink guard  64  still drawn away as a result), the ejection head  24  makes contact with the wiper blade  62 . To rephrase, the ink guard  64  is in a state in which it is drawn away from the ejection head  24  prior to the ejection head  24  making contact with the wiper blade  62 . Meanwhile, as described earlier, the wiper blade  62  is formed from an elastic material such as silicon rubber or the like, and thus the wiper blade  62  deforms upon making contact with the ejection head  24 . Accordingly, the wiper blade  62  is pressed against the nozzle opening surface  25  formed on the bottom surface of the ejection head  24  as a result of the movement of the carriage case  22 , and when the carriage case  22  is moved in this state, foreign objects such as ink adhering to the nozzle opening surface  25  are wiped away by the wiper blade  62 . 
         [0038]    If the carriage case  22  continues to move while the wiper blade  62  wipes away foreign objects from the nozzle opening surface  25 , the guide rails  26  will eventually pass, and as a result, the guide cams  66  will attempt to return to their original position.  FIG. 5D  illustrates a state in which the guide rails  26  have passed, and the guide cams  66  are beginning to return as a result thereof. As illustrated in  FIG. 5D , when the guide cams  66  attempt to return to their original position, the ink guard  64 , which has been drawn away, also attempts to return to its original position. Meanwhile, at this stage, the wiper blade  62  remains in a state in which it is pressed against the nozzle opening surface  25 . To rephrase, the ink guard  64  begins to return to its original position at a stage in which the wiper blade  62  is still pressed against the nozzle opening surface  25 . 
         [0039]      FIG. 5E  illustrates a state occurring immediately before the wiper blade  62  leaves the nozzle opening surface  25  and returns to its original position. At this stage, the ink guard  64  is already in an upright state. Accordingly, even if the wiper blade  62 , which has been pressed against the nozzle opening surface  25  and has been deformed as a result, forcefully returns to its original position and scatters the ink and the like wiped off from the nozzle opening surface  25  at that time, the ink guard  64 , which has already returned to its upright state, can guard against this scattering. It is therefore possible to completely remove the risk of the other portions of the ink jet printer  10  being soiled. Further descriptions on this point will be provided hereinafter. 
         [0040]    In the wiping operation, it is of course necessary for the wiper blade  62  to be in a state in which it is pressed against the nozzle opening surface  25 . Naturally, as a result, it is difficult to avoid the wiper blade  62  that has been deformed from returning to its original shape after the wiping operation has ended. If the force by which the wiper blade  62  attempts to return to its original shape is suppressed, it is possible to suppress the ink and the like wiped from the nozzle opening surface  25  from scattering. However, unless the wiper blade  62  is completely suppressed from returning, simply suppressing the force by which the wiper blade  62  attempts to return merely reduces the amount of scattering, and thus it is not possible to completely eliminate the scattering. Accordingly, rather than preventing the wiper blade  62  from scattering ink, this embodiment ensures that the surrounding area will not be soiled even if ink is scattered. As described above, as long as the wiper blade  62  deforms, it is not possible to completely prevent ink from scattering; however, if the scattered ink is prevented from soiling the surrounding area, the same effect can be realized to its full extent. Accordingly, with the ink jet printer  10  according to this embodiment, the risk that ink that has been wiped off by the wiper blade  62  splashes back and soils the surrounding area can be completely eliminated. 
         [0041]    Although a fluid ejection apparatus according to this embodiment has been described using the ink jet printer  10  as an example, the invention is not limited to the aforementioned embodiment or variations thereof; many other embodiments are possible without departing from the spirit of the invention. 
         [0042]    The invention can be used in technology that ejects a fluid such as ink onto a medium such as a print sheet.