Abstract:
In an inkjet recording device, ink droplets remaining on a nozzle surface are wiped off and the wiped off ink droplets are prevented from being scattered so as to stably form good quality images. When the wiper blade wiping the nozzle surface of the recording heads to wipe off the ink droplets and the like is separated from the nozzle surface and the bend of the wiper blade is straightened to restore to its idle position, a reaction force eliminating member absorbs the reaction force generated and softly restores the wiper blade to its idle position. As a result, the reaction force caused when the bend of the wiper blade is suddenly straightened is controlled, thereby preventing the ink drops and foreign matter on the header of the wiper blade from being scattered and avoiding the contamination of the inside of the inkjet recording device.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an inkjet recording device for printing images on a printing medium by ejecting ink, and more particularly to a wiping device for eliminating fluid attached to the nozzle of the inkjet printer. 
         [0003]    2. Description of the Related Art 
         [0004]    An inkjet recording device is generally required to have a mechanism for maintaining the performance of the recording head that ejects ink droplets. As the functions of the mechanism, there are, for example, a capping function to prevent the nozzles ejecting ink droplets from dehydrating, a pumping function to fill the recording head with ink, and a nozzle cleaning function to clean the surface of the nozzle array of the recording head. Among those functions, the nozzle cleaning function is important, because when ejected ink droplets remain on the nozzle surface or foreign matter adheres to the nozzle surface, ink droplets may be ejected in the undesired direction or may become unable to be ejected, thereby seriously degrading the printing quality and image forming performance. 
         [0005]    Furthermore, the speed of image forming processing has been increased in recent inkjet recording devices. To that end, throughputs improved by increasing the number of nozzles of the recording head so that more ink droplets can be ejected in a single scan. As a result, more ink droplets may be left behind on the nozzle surface and the remaining ink droplets are wiped off with a wiper blade. However, when the nozzle surface is wiped off by the wiper blade as described, there is a problem that the ink droplets wiped off from the nozzle surface and adhered to the wiper blade may be flicked off at the moment when the wiper blade is separated from the recording head after wiping the nozzle surface due to the elastic reaction of the wiper blade, thereby contaminating the inside of the printer body with the spattered ink droplets and degrading the printing quality. 
         [0006]    To prevent the ink droplets adhered to the wiper blade from flicking off from the wiper blade, according to an inkjet recording device disclosed in the Patent Document 1 below, the wiper blade separates from the nozzle surface after passing the middle of the nozzle surface but before passing the end of the nozzle surface so that the wiper blade and the recording head are no longer in contact after the elastically deformed condition of the wiper blade is released. 
         [0007]    Further, according to an inkjet recording device disclosed in the Patent Document 2 below, when the ink droplets left behind on the nozzle surface of the recording head are wiped with a wiper blade capable of moving in the direction vertical to the height direction of the nozzle surface of the recording head, a carriage on which the recording head is mounted while performing a round-trip scanning movement is stopped in the middle of wiping operations while the wiper blade is bent. Then the wiper blade is moved to wipe the remaining nozzle surface while the wiper blade is gradually being lowered so as to reduce the elastic deformation of the wiper bade, thereby reducing the amount of flicked ink droplets. 
         [0008]    According to an inkjet recording device disclosed in the Patent Document 3 below, the wiper member for wiping off the nozzle surface of a recording head includes an ink absorbing section having elastic and superior water-absorbing characteristics and a wiping section provided adjacent to the ink absorbing section, closer to the nozzle surface than the ink absorbing section, and having lower water-absorbing characteristics. As a result, the wiping section wipes the ink droplets and the paper dust on the nozzle surface and then the wiped ink droplets and the like are absorbed into the ink absorbing section, thereby preventing the ink droplets from scattering. 
         [0009]    Further, according to an inkjet recording device disclosed in the Patent Document 4 below, there is provided an escape surface on the downstream side of the recording head (on the side where the wiper blade separates from the recording head) such that the height direction of the recording head vertical to the nozzle surface is gradually reduced as the wiper blade approaches the end of the downstream side of the recording head. Because of this structure, when the wiper blade wiping the nozzle surface proceeds to wipe the escape surface, the elastic deformation of the wiper blade is gradually reduced, thereby preventing the remaining ink droplets on the header of the wiper blade from flicking off caused by the reaction force due to suddenly eliminating the elastic deformation of the wiper blade. 
         [0010]    Patent Document 1: Japanese Patent Publication No: 3234087 
         [0011]    Patent Document 2: Japanese Patent Application Publication No: 2006-192693 
         [0012]    Patent Document 3: Japanese Patent Application Publication No: 2003-1833 
         [0013]    Patent Document 4: Japanese Patent Application Publication No: 2002-79680 
         [0014]    However, when the wiper blade separates from the nozzle surface after passing the middle of the nozzle surface but before passing the end of the nozzle surface as described in the Patent Document 1, or when the wiper blade gradually recedes from the nozzle surface during the wiping operations as described in the Patent Document 2, the portion between the middle to the end of the nozzle surface cannot be sufficiently wiped due to insufficient contacting pressure exerted by the wiper blade. As a result, the nozzle surface cannot be cleaned sufficiently and, disadvantageously, the ink droplets remaining on the nozzle surface due to the insufficient cleaning may contaminate recording paper. 
         [0015]    Further, even when the wiper blade is arranged so that the wiping section having lower water-absorbing characteristics wipes the ink droplets and the paper dust on the nozzle surface, and then the wiped ink droplets and the like are absorbed into the ink absorbing section having superior water-absorbing characteristics as described in the Patent Document 3, the ink droplets may not be sufficiently absorbed into the ink absorbing section in a case where the paper dust adheres to the surface of the ink absorbing section. 
         [0016]    Still further, the ink absorbing section is usually formed of an interconnected porous material so as to have water-absorbing characteristics. Since the holes of the porous material are likely to be sealed with a material such as the pigment of ink, the ink absorbing section may not stably absorb ink droplets for the long term. As a result, unfortunately, the scattering of ink droplets cannot be sufficiently prevented. 
         [0017]    Further, since the wiper member includes an ink absorbing section having elastic and superior water-absorbing characteristics and a wiping section having lower water-absorbing characteristics, the structure of the wiper member is complicated, thereby complicating the forming process and increasing the cost of the wiper member. 
         [0018]    Further, since the escape surface is formed on the downstream side of the nozzle surface to be wiped with the wiper blade as described in the Patent Document 4, the wiper blade cannot contact the escape surface with sufficient contact pressure. As a result, more ink droplets are likely to be left behind on the escape surface. In addition, if the left ink droplets are accumulated on the escape surface, the accumulated ink droplets may contaminate recording paper. 
       SUMMARY OF THE INVENTION 
       [0019]    The present invention is made in light of the above problems and may provide an inkjet recording device capable of wiping the nozzle surface to the end of the nozzle surface with sufficient contact pressure so as to wipe off the remaining ink droplets on the nozzle surface, thereby preventing the wiped ink droplets from scattering to stably form good quality images. 
         [0020]    According to one aspect of the present invention, there is provide an inkjet recording device including a recording head ejecting ink droplets to record a character and an image onto a recording medium, a carriage with the recording head mounted thereon performing a round-trip scanning movement, a wiping unit, and a blade elevating unit disposed within a scanning range of the carriage and moving the wiping unit upward and downward in the height direction of the nozzle surface of the recording head. The wiping unit includes a wiper blade made of an elastic body and formed in a flat plate shape for wiping a nozzle surface of the recording head, and a reaction force eliminating member reducing a reaction force of the wiper blade generated when a wiping operations of the wiper blade is terminated. 
         [0021]    According to another aspect of the present invention, the reaction force eliminating member has a spring characteristic, is made of a material having a Young&#39;s modulus higher than that of the wiper blade, and has a flat plate shape. 
         [0022]    According to still another aspect of the present invention, a supporting unit supports the wiper blade and the reaction force eliminating member has convex parts provided one on each upper end part thereof, the convex parts face the wiper blade, and the wiper blade and the reaction force eliminating member stand substantially upright on the supporting unit. 
         [0023]    According to still another aspect of the present invention, the supporting unit is removably attached to the blade elevating unit. 
         [0024]    According to an embodiment of the present invention, the header of the wiper blade wipes the nozzle surface of the recording head to wipe off the ink droplets and the like on the nozzle surface. When the header of the nozzle surface separates from the nozzle surface, the reacting force eliminating member absorbs the reaction force of the wiper blade so that the bent wiper blade is restored to its upright original position. As a result, the reaction force that would be otherwise generated by suddenly restoring the bent blade can be controlled, the scattering of the ink droplets and the foreign matter on the header of the wiper blade can be effectively prevented, and the contamination inside the inkjet recording device can be avoided accordingly. 
         [0025]    Further, the reaction force generated when the bent wiper blade is restored can be stably absorbed when the reaction force elimination member is formed so as to have a spring characteristic, made of a material having a Young&#39;s modulus higher than that of the wiper blade, and has a flat plate shape. 
         [0026]    Further, convex parts are provided one each on surfaces of the upper portion of the reaction force eliminating member such that the convex parts face the wiper blade. Then the supporting unit supports the reaction force eliminating member and the wiper blade so that the reaction force eliminating member and the wiper blade stand upright to secure the position accuracy of the wiper blade and the reaction force eliminating member, thereby enabling the secure absorption of the reaction force when the bent wiper blade is restored. 
         [0027]    Further, the wiper blade can be easily replaced when the supporting unit is provided so as to be attached to and detached from the blade elevating unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a perspective view of an inkjet recording device according to an embodiment of the present invention when viewed from a front side; 
           [0029]      FIG. 2  is a cut-open side view showing the configuration of a mechanical part of the inkjet recording device; 
           [0030]      FIG. 3  is a top view showing the configuration of a mechanical part of the inkjet recording device; 
           [0031]      FIG. 4  is a cut-open perspective view showing a maintaining and restoring mechanical part of the inkjet recording device; 
           [0032]      FIG. 5  is a drawing showing a wiper blade used in the inkjet recording device; 
           [0033]      FIGS. 6A and 6B  are drawings showing the configuration of a reaction force eliminating member used in the inkjet recording device; 
           [0034]      FIGS. 7A and 7B  are drawings showing the configuration of a supporting member used in the inkjet recording device; 
           [0035]      FIG. 8  is a drawing showing the configuration of a blade elevating mechanical part used in the inkjet recording device; 
           [0036]      FIGS. 9A and 9B  are drawings showing where the supporting member is engaged with the blade elevating member; and 
           [0037]      FIGS. 10A through 10C  are drawings showing the wiping operation of the wiper blade. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]      FIG. 1  is a perspective view of an inkjet recording device according to an embodiment of the present invention when viewed from a front side. The inkjet recording device includes a device main body  1 , a paper feeding tray  2  attached to the device main body  1  and storing recording papers, a paper discharging tray  3  attached to the device main body  1  and storing the recording papers on which images are recorded. An upper cover  4  is provided above the device main body  1  so as to be opened and closed. There is a cartridge mounting section  6  projected through a part of a front surface  5  of the device main body  1  and lower than the upper cover  4 . There is an operating section  7  above the cartridge mounting section  6 , including operation keys and a display. The cartridge mounting section  6  includes a front cover  8  to be opened and closed, and while the front cover  8  is opened, ink cartridges  9  which are main tanks for supplying inks can be detached and attached. 
         [0039]      FIGS. 2 and 3  show a mechanical part of the inkjet recording device. The mechanical part includes a guide rod  11 , a stay  12 , a carriage  13 , and recording heads  14 . The guide rod  11  and the stay  12  are guiding members placed laterally between the side plates of the device main body  1 . Further, the guide rod  11  and the stay  12  hold the carriage  13  so that the carriage  13  can slide in a main scanning direction. The carriage  13  is moved in the main scanning direction by a main scanning motor (not shown). In the carriage  13 , there are attached recording heads  14  including the inkjet heads that eject the ink droplets of the corresponding colors of yellow (Y), cyan (C), magenta (M), and black (B). The plural ink ejecting openings of the inkjet heads are arranged in the direction vertical to the main scanning direction and the ink ejected from the plural ink ejecting openings is directed downward. As an energy generating unit for ejecting the ink droplets, for example, a device such as a piezoelectric device, a thermal actuator utilizing the phase change due to the film boiling phenomenon of fluid using an electrothermal conversion device such as a heat-generating resistor member, a shape-memory-alloy actuator utilizing the metallic phase change due to temperature change, and an electrostatic actuator utilizing electrostatic power may be used. In this embodiment, for example, the piezoelectric actuator is used in the recording head  14 . 
         [0040]    In addition, in the carriage  13 , there are sub tanks  15  that are fluid containers for supplying each ink to the corresponding recording head  14 . Each ink is supplied from the corresponding ink cartridge  9  to the corresponding sub tank  15  via the corresponding ink supply tube  16 . The ink cartridges  9  store the corresponding inks of yellow (Y), cyan (C), magenta (M), and black (B) as the color components of the inkjet recording device. The sub tanks  15  supply the ink to the recording heads  14  and the ink cartridges  9  supply the ink to the sub tanks  15 . The sub tanks  15  and the ink cartridges  9  constitute an ink supplying device. 
         [0041]    In the inkjet recording device, there is a paper feeding section for feeding the recording papers  18  accumulated on the paper accumulating section (thick plate)  17  of the paper feeding tray  2 . The paper feeding section includes a half-moon roller (paper feeding roller)  19  and a separation pad  20 . The half-moon roller (paper feeding roller)  19  separates and feeds one sheet of recording papers  18  at a time from the paper accumulating section  17 . The separation pad  20  faces the paper feeding roller  19 . The separation pad  20  is pressed toward the side of the paper feeding roller  19 . 
         [0042]    Further, in the inkjet recording device, there is a feeding section for feeding the recording papers  18  from the paper feeding tray  2  to a position below the recording heads  14  through a guide  21 . The feeding section includes a conveying belt  22 , a counter roller  23 , a conveying guide  24 , a pressing member  25 , a head pressure roller  26 , a charge roller  27 , a conveying roller  28 , a tension roller  29 , and a guide member  30 . The conveying belt  22  electrostatically attracts and conveys the recording paper  18 . The counter roller  23  sandwiches the recording paper  18  from the paper feeding section through the guide  21  with the conveying belt  22  to convey the sandwiched recording paper  18 . The conveying guide  24  changes the feeding direction of the recording paper  18  fed substantially vertically upward by substantially 90 degrees so that the recording paper  18  is placed on the conveying belt  22 . The head pressure roller  26  is pressed toward the conveying belt  22  by the pressing member  25 . The charge roller  27  is a charging unit for charging the surface of the conveying belt  22 . Herein, the conveying belt  22  is an endless belt suspended between the conveying roller  28  and the tension roller  29  so as to rotate in the belt conveying direction as shown in  FIG. 3 . The charge roller  27  contacts the surface of the conveying belt  22  and is disposed so that the charge roller  27  rotates according to the rotation of the conveying belt  22 . 
         [0043]    At the rear side of the conveying belt  22 , there is the guide member  30  disposed corresponding to the printing area defined by the recording heads  14 . The upper surface of the guide member  30  protrudes to the side of the recording heads  14  beyond the upper tangent line between the conveying roller  28  and the tension roller  29  each roller supporting the conveying belt  22 . Because of this structure, the conveying belt  22  is pressed upward and guided by the upper surface of the guide member  30 , thereby maintaining the high-precision flatness of the conveying belt  22 . 
         [0044]    Further, in the inkjet recording device, there is a discharging section for discharging the recording paper  18  recorded on by the recording heads  14 . The discharging section includes a separating click  31  and paper discharging rollers  32  and  33 . The separating click  31  separates the recording paper  18  from the conveying belt  22 . The paper discharging tray  3  is disposed below the paper discharging roller  32 . The position between the paper discharging rollers  32  and  33  is set higher to some extent than the paper discharging tray  3  so that as many recording papers  18  as possible can be stored in the paper discharging tray  3 . 
         [0045]    Further, a double-sided paper feeding unit  34  is removably attached to the rear side of the device main body  1 . The double-sided paper feeding unit  24  receives the recording paper  18  returned by the reverse rotation of the conveying belt  22 , turns the recording paper  18  over, and feeds the recording paper  18  to a position between the counter roller  28  and the conveying belt  22  again. On the double-sided paper feeding unit  34 , there is a manual paper feeding unit  35 . 
         [0046]    Further, as shown in  FIG. 3 , there is a maintaining and restoring mechanical section  36  disposed in a non-printing area on one side in the scanning direction of the carriage  13 . The maintaining and restoring mechanical section  36  is a reliability maintaining unit for maintaining and restoring the condition of the nozzles of the recording heads  14 . Further, there is an ink collecting container  37  disposed in another non-printing area on the other side in the scanning direction of the carriage  13 . 
         [0047]    As shown in  FIG. 4 , the maintaining and restoring mechanical section  36  includes capping members  38   a  through  38   d , a suction pump  39 , a suction cap  40  in communication with the suction pump  39 , a wiping unit  41  for cleaning the nozzle surface by wiping, and an ink collecting section  42 . The capping members  38   a  through  38   d  cap the nozzle surface to prevent the nozzles of the recording heads  14  from drying. The suction pump  39  is provided for filling the recording heads  14  with ink. 
         [0048]    The wiping unit  41  includes a wiper blade  43 , a reaction force eliminating member  44 , a supporting member  45 , and a blade elevating mechanical section  46 . The wiper blade  43  is made of an elastic material such a rubber elastic material and formed in a tabular shape as shown in  FIG. 5 . The wiper blade  43  includes plural, for example three, attaching holes  47  on the middle lower side of the wiper blade  43 . The wiper blade  43  wipes off the ink droplets and foreign matter attached to the nozzle surface while pressing the header section of the wiper blade  43  toward the nozzle surface. The reaction force eliminating member  44  has a spring characteristic and is made of a material having a Young&#39;s modulus higher than the wiper blade  43  has such as Ethylene Propylene Methylene Linkage (EPML) and silicon as an elastic material, stainless and aluminum as the metallic material of a non-elastic material, and ABS and polyoxymethylene (POM) as a resin material and formed in a tabular shape as shown in  FIGS. 6A and 6B . The reaction force eliminating member  44  includes a blade contacting section  49  and attaching holes  50 . The blade contacting section  49  has two convex parts  48  provided one on each upper side so that the convex parts  48  contact the wiper blade  43 . The attaching holes  50  are formed in the middle part of the reaction force eliminating member  44 . 
         [0049]    As shown in  FIGS. 7A and 7B , the wiper blade  43  and the reaction force eliminating member  44  are attached to the supporting member  45  such that the convex parts  48  formed on the blade contacting section  49  of the reaction force eliminating member  44  face and contact the wiper blade  43 . The supporting member  45  has a boss  51  at the middle lower part for elevating the supporting member  45  and a pair of guide rollers  52  provided on each end side in the width direction. The blade elevating mechanical section  46  is provided between the both ends in the width direction as shown in  FIG. 4  and includes guide grooves  53  for guiding the guide rollers  52  of the supporting member  45  and an axle cam  55  having a plate cam  54  at one end of the axle cam  55  as shown in  FIG. 8 . The plate cam  54 , as shown in  FIGS. 9A and 9B , has a cam groove  56  on the surface of the plate cam  54  for engaging the boss  51  for elevating the supporting member  45  and a cut-out section  57  disposed substantially where the cam groove  56  is closest to the rotating center of the cam groove  56  so that the boss  51  is inserted through the cut-out section  57 . The axle cam  55  is supported by plural guide sections  58  and has a rotation transmission section  59  connected to a rotation driving section (not shown) through the other end of the rotation transmission section  59 . 
         [0050]    To configure the wiping unit  40 , first, the axle cam  55  of the blade elevating mechanical section  46  is positioned so that the cut-out section  57  of the plate cam  54  is positioned at the top of the plate cam  54 . Next, the guide rollers  53  of the supporting member  45  with the wiper blade  43  and the reaction force eliminating member  44  attached to the supporting member  45  are inserted into the guide grooves  53 . Then, the boss  51  for elevating the supporting member  54  is inserted into the cut-out section  54  so that the boss  51  is engaged into the cam groove  56 . In this manner, the supporting member  45  is attached to the blade elevating mechanical section  46  to configure the wiping unit  40 . According to this mechanism where the supporting member  45  with the wiper blade  43  and the reaction force eliminating member  44  fixed to the supporting member  45  is attached to the blade elevating mechanical section  46 , the wiper blade  43  and the reaction force eliminating member  44  are raised and lowered according to the movement of the supporting member  45  up and down by rotating the axle cam  55  so as to move the boss  51  upward and downward along the cam groove  56  of the plate cam  54 . 
         [0051]    The operation of wiping off the ink droplets and foreign matter attached to the nozzle surface of the recording heads  14  using the wiper blade  43  being moved upward and downward by the blade elevating mechanical section  46  is described with reference to  FIGS. 10A through 10C . 
         [0052]    When the recording heads  14  moving at a constant speed of the carriage  13  approach the maintaining and restoring mechanical section  36 , the supporting member  45  with the wiper blade  43  and the reaction force eliminating member  44  fixed to the supporting member  45  is raised by rotating the axle cam  55  of the blade elevating mechanical section  46  to the position where the reaction force eliminating member  44  does not contact the nozzle surface but the header portion of the wiper blade  43  protrudes by a prescribed length beyond the nozzle surface  141  of the recording heads  14  as shown in  FIG. 10A . In this condition, when the moving recording heads  14  contact the wiper blade  43 , as shown in  FIG. 10B , the wiper blade  43  bends and the header portion of the wiper blade  43  is in contact with and pressed toward the nozzle surface  141 . As a result, as the recording heads  14  move, the ink droplets and foreign matter attached to the nozzle surface  141  are wiped off and removed. Then, the recording heads  14  further move. When the end of the nozzle surface  141  passes over the header portion of the bent wiper blade  43  and the header portion of the wiper blade  43  separates from the nozzle surface  141  and while the bend of the wiper blade  43  is returned to its idle position, both end portions of the wiper blade  43  contact the corresponding convex parts  48  of the blade contacting sections  49  of the reaction force eliminating member  44  and the reaction force generated when the bent of the wiper blade  43  is straightened is absorbed by the spring characteristic of the reaction force eliminating member  44  so as to return the wiper blade  43  to its idle position. Because of this feature, the reaction force generated when the bend of the wiper blade  43  is suddenly straightened can be controlled, thereby preventing the ink droplets and foreign matter attached to the header portion of the wiper blade  43  from being scattered and avoiding the contamination in the device main body  1  of the inkjet recording device and the degradation of the quality of the forming images. 
         [0053]    When the recording heads  14  passed beyond the maintaining and restoring mechanical section  36 , the supporting member  45  with the wiper blade  43  and reaction force eliminating member  44  fixed to the supporting member  45  is lifted down to a prescribed position by rotating the axle cam  55  of the blade elevating mechanical section  46 . 
         [0054]    To remove and replace the wiper blade  43  of the maintaining and restoring mechanical section  36 , the axle cam  55  of the blade elevating mechanical section  46  is rotated so that the cut-out section  57  of the plate cam  54  is positioned at the boss  51  for elevating the supporting member  45  and the supporting member  45  is pulled out of the blade elevating mechanical section  46 . Then the wiper blade  43  and the reaction force eliminating member  44  are removed from the supporting member  45  and replaced by a new wiper blade  43  and a new reaction force eliminating member  44 . In this manner, wiper blade  43  can be replaced easily and the maintenance operation can be performed easily. 
         [0055]    The present invention is not limited to the above-mentioned embodiments, and variations and modifications may be made without departing from the scope of the present invention. 
         [0056]    The present application is based on and claims the benefit of priority of Japanese Patent Application No. 2007-059388, filed on Mar. 9, 2007 the entire contents of which are hereby incorporated by reference.