Patent Abstract:
An ink jet recording apparatus includes a recording head having an ink ejection surface; a blade for wiping the ink ejection surface; a blade cleaning device that cleans the blade by collecting contamination liquid deposited on the blade and including at least ink; a cleaning liquid supplying device that supplies, to the blade, cleaning liquid mainly comprising liquid having a volatility lower than the ink; a residual ink absorbing material provided at such a position that it is out of contact to the blade; and a discharge path for discharging the contamination ink collected by the blade cleaning device to the residual ink absorbing material.

Full Description:
FIELD OF THE INVENTION AND RELATED ART 
     The present invention relates to an ink jet recording apparatus which records on a recording medium by ejecting ink. In particular, it relates to an ink jet recording apparatus having a means for wiping the ink ejecting surface of its recording head. 
     An ink jet recording apparatus forms letters, pictures, and the like images, on recording medium, by adhering to the recording medium, the ink which it ejects through the nozzles of its recording head. It is a recording apparatus of the nonimpact type, being therefore low in noise, and also, is capable of recording at a high speed as well as high level of density. On the other hand, however, it suffers from its own problems, because it ejects ink through minute nozzles. That is, while an ink jet recording apparatus is used, the ink which does not contribute to recording sometimes adheres to the ink ejecting surface of its recording head. The adhesion of ink to the ink ejecting surface interferes with the ejection of ink from the recording head. For example, it causes the recording head to eject ink in the wrong direction, or prevents the recording head from ejecting ink. Therefore, an ink jet recording apparatus is provided with a means for wiping clean (which hereafter may be referred to simply as “wiping”) the ink ejecting surface of its recording head, in order to remove the ink having adhered to the ink ejecting surface. As a wiping means, such as the one described above, a blade capable of gliding on the ink ejecting surface while remaining in contact with the ink ejecting surface is used. More specifically, the ink having adhered to the ink ejecting surface of the recording head is removed by wiping the surface with the blade. Further, it is desired that an ink jet recording apparatus is provided with a means for cleaning the cleaning blade, in order to maintain the wiping performance of the blade. The blade cleaning means is to remove the liquid (which hereafter will be referred to as contaminated ink), which includes at least the ink having adhered to the blade while the blade was wiping the ink ejecting surface. 
     An example of an ink jet recording apparatus provided with a blade cleaning means is recorded in No. 3428893 of the official gazette of Patent Office of Japan. In the case of this ink jet recording apparatus, the contaminated ink having adhered to the blade is wiped away by placing the ink in contact with the edge portion of the blade cleaning member of the blade cleaning means. This cleaning method, however, is problematic in that as a blade cleaning means, such as the above described one, is repeatedly used, the contaminated ink accumulates on the blade cleaning means. If the ink ejecting surface is wiped with the cleaning blade on which the contaminated ink has accumulated by a substantial amount, the contaminated ink on the cleaning blade transfers back onto the ink ejecting surface, recontaminating the ink ejecting surface of the recording head. 
     Further, in recent years, the development of inks which are superior in recording density, water resistance and weather resistance, has been in limelight. However, inks which are superior in durability (fastness) are generally highly agglutinative, being therefore likely to more quickly increase in viscosity, and/or more quickly solidify after it adheres to the ink ejecting surface of the recording head of an ink jet recording apparatus, than an ordinary ink. Thus, the length of time it takes for an ink jet recording head to begin improperly ejecting ink after contaminated ink, which is higher in durability (fastness), is transferred back onto the ink ejecting surface of the recording head is substantially shorter than the length of time it takes for the ink jet recording head to begin improperly ejecting ink after contaminated ink, which is lower in durability (fastness), is transferred back onto the ink ejecting surface of the recording head. 
     Proposed in Japanese Laid-open Patent Application H07-068791 is a blade cleaning means, which is provided with a porous member for absorbing the contaminated ink to prevent the contaminated ink from transferring back onto the ink ejecting surface. According to this proposal, the contaminated ink on the blade is recovered by using a capillary tube, and then, is absorbed from the capillary tube by a porous member placed in contact with the opposite end the capillary tube from the end through the contaminated ink is recovered. 
     In the case of the structure of the blade cleaning means recorded in Japanese Laid-open Patent Application H07-068791, as an ink (pigment-based ink, for example) which is higher in durability (fastness) is used, the contaminated ink increases in viscosity in the porous member and/or capillary tube of a blade cleaning means, and/or solidifies in the porous member and/or capillary tube. That is, the when an ink which is high in durability (fastness) is used, the porous member and/or capillary tube, with which the blade cleaning means is provided, are likely to be plugged up, and therefore, the porous member is likely to deteriorate in the ability for absorbing the contaminated ink, earlier than expected. As one of the methods for solving this problem, it is possible to impregnate the porous member with liquid capable of dissolving the contaminated ink. However, the employment of this type of method subjects the joint between the capillary tube and porous member to the load generated by the weight of the contaminated ink in the porous member. This load interferes with the flow of the contaminated ink from the capillary tube into the porous member, making it difficult to increase the amount by which the contaminated ink can be absorbed by the porous member. Therefore, it is difficult to continuously and satisfactorily wipe clean the ink ejecting surface of a recording head for a long time. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention, which was made in consideration of the above described problems of the prior art, is to provide an ink jet recording apparatus, the amount by which it can store the contaminated ink recovered by its blade cleaning means is significantly greater than the amount by which an ink jet recording apparatus in accordance with the prior art can stores the contaminated ink recovered by its blade cleaning means. 
     Another object of the present invention is to provide an ink jet recording apparatus, which is capable of continuously and satisfactorily wiping clean the ink ejecting surface of its recording head for a long period of time, and therefore, is capable of continuously and satisfactorily ejecting ink for a long period of time, and yet, is simple in structure. Another object of the present invention is to provide an ink jet recording apparatus, the ink ejecting performance of which remains the same whether it is used with an ink which is high in durability (fastness), or an ink which is normal in durability (fastness). 
     According to an aspect of the present invention, there is provided an ink jet recording apparatus comprising a recording head having an ink ejection surface; a blade for wiping said ink ejection surface; blade cleaning means for cleaning said blade by collecting contamination liquid deposited on said blade and including at least ink; cleaning liquid supplying means for supplying, to said blade, cleaning liquid mainly comprising liquid having a volatility lower than the ink. A residual ink absorbing material provided at such a position that it is out of contact to said blade; and a discharge path for discharging the contamination ink collected by said blade cleaning means to said residual ink absorbing material. 
     According to the present invention, it is possible to provide an ink jet recording apparatus, which is capable of maintaining the ink ejecting performance of its recording head at a satisfactorily level for a long period of time, by being capable of continuously and satisfactorily wiping clean the ink ejecting surface of its recording head for a long period of time. 
     These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of the ink jet recording apparatus in the first of the preferred embodiments of the present invention. 
         FIG. 2  is a plan view of the ink ejecting surface of the recording head shown in  FIG. 1 . 
         FIG. 3  is a perspective view of the maintenance unit shown in  FIG. 1 . 
         FIG. 4  is a perspective view of the blade cleaning means shown in  FIG. 1 . 
         FIG. 5  is a perspective view of the blade cleaning means in another preferred embodiment of the present invention. 
         FIG. 6A  is a drawing of the blade cleaning means, which is on standby. 
         FIG. 6B  is a drawing for describing the wiping step in the recording head maintaining process. 
         FIG. 6C  is a drawing for described the blade cleaning step in the recording head maintaining process. 
         FIG. 6D  is a drawing for describing the cleaning liquid applying step in the recording head maintaining process. 
         FIG. 6E  is a drawing for describing the swinging step in the recording head maintaining process. 
         FIG. 6F  is a drawing for describing the recovery step in the recording head maintaining process. 
         FIG. 7  is a perspective view of the maintenance unit in another preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Hereinafter, the preferred embodiments of the present invention will be described with reference to the appended drawings. 
       FIG. 1  is a perspective view of the ink jet recording apparatus in the first preferred embodiment of the present invention. An ink jet recording apparatus  100  has a recording head  101  for ejecting ink, and a carriage  102  on which the recording head  101  is mounted. 
     The carriage  102  is shaped so that an ink container  102  for supplying the recording head  101  with recording ink can be mounted on the carriage  102 . It is structured so that the ink container  109  is removably mountable thereon, and also, the ink container  102  thereon can be replaced with another ink container  102 . 
     Further, one end of the carriage  102  is supported by a carriage guide  112 , which extends in the direction indicated by a double-headed arrow mark in  FIG. 1 . Further, the ink jet recording apparatus  100  is provided with a combination of a motor  103  and a driving force transmitting mechanism  104 , which is for moving the carriage  102  back and forth along the carriage guide  112 . 
     Further, the ink jet recording apparatus  100  is provided with a paper feeding mechanism  106 , which is positioned so that as ink is ejecting out of the recording head  101 , it lands on a recording medium  105  in a manner to form an image on the recording medium  105 . 
     Further, the ink jet recording apparatus  100  is provided with a maintenance unit  107  for maintaining the recording head  101  in terms of recording performance, and also, for restoring the recording head  101  in terms of recording performance. The maintenance unit  107  is located outside the path of the recording medium  105 . The structural components of the ink jet recording apparatus  100  described above are attached to the chassis  108  of the ink jet recording apparatus  100 . 
     In order to control the carriage  102  in terms of its position in its moving range, the ink jet recording apparatus  100  is provided with a code strip  111 , which is parallel to the carriage guide  112 . Further, the carriage  102  is provided with a linear encoder (unshown), which is capable of reading the black bars printed on the code strip  110  with preset intervals. Thus, the ink jet recording apparatus  100  can precisely determine the location of the carriage  101 . Further, the ink jet recording apparatus  100  is provided with a referential position for the carriage  102 , which is within the moving (shuttling) range of the carriage  102 , and which is used to initialize the ink jet recording apparatus  100  in terms of the position (absolute position) of the recording head  101 . As for the methods for initializing the ink jet recording apparatus  100  in terms of the recording head position, there are the method which causes the carriage  101  to come into contact with a specific member, method which provides a special portion of the code strip  111  with a printed pattern dedicated to the initialization, etc. 
       FIG. 2  is a drawing for describing the structure of the ink ejecting surface  201  of the recording head  101 . The ink ejecting surface  201  has the opening of each of the multiple ink ejecting nozzles  202 . Each ink ejecting nozzle  202  (which hereafter will be referred to simply as ink nozzle  202 ) is provided with a means for generating the energy for ejecting ink. As the means for generating the ink ejecting energy, a heater or a piezoelectric element is used. In a case where a heater is used as the means for generating the ink ejecting energy, the heater is driven to very quickly heat the ink in the nozzle, in order to boil the ink in the so-called film-boiling fashion. As the ink boils in the film-boiling fashion, the force from the expansion of a bubble generated by the boiling of the ink is used to cause the ink in the nozzle to eject out of the nozzle. In a case where a piezoelectric element is used as the means for ejecting ink, each of the ink passages, or a part of the ink storage chamber, is provided with a piezoelectric element. If it is required to cause a given nozzle to eject out the ink therein, the piezoelectric element in the nozzle is made to deform by a preset electrical signal. In other words, the ink in the nozzle is pushed out (ejected out) by driving the piezoelectric element in the nozzle. 
     As the means for driving the means for generating the ink ejecting energy, an electrical signal is used. The electrical signal is supplied to the carriage  102  from the control chip (unshown), which the ink jet recording apparatus  100  has, through a flexible cable  110 . As the electrical signal is supplied to the carriage  102 , it is transmitted to the recording head  101 , and drives the ink ejecting energy generating means, causing thereby the ink in the nozzle to eject out of the nozzle. 
     Each electrical signal is transmitted with a preset timing to cause a specific nozzle to eject the ink in the nozzle onto the recording medium  105  supplied from the recording medium (paper) feeding mechanism  106 , while the recording medium  101  is conveyed at a preset pitch in synchronism with the movement of the carriage  102 . As a result, ink is deposited on the desired points across the entirety of the recording medium  105 . 
     In order to ensure that the ink is accurately ejected from the recording head  101 , the recording head  101  has to be properly maintained. The maintenance of the recording head  101  is carried out by a maintenance unit  107 , which wipes the ink ejecting surface  201  of the recording head  101  to remove the unwanted matters on the ink ejecting surface  201 , and also, causes the nozzle to discharge the ink therein to remove the bubbles remaining in the nozzle, and also, to remove the impurities having entered the nozzle. 
     Next, the structure of the maintenance unit  107  will be described in detailed with reference to  FIG. 3 . The maintenance unit  107  has a capping means  308 , a pair of blades  301 , a blade cleaning means  303 , a cleaning liquid supplying means  305 , and a waste ink absorbing means  310 . 
     Each blade  301 , that is, a wiper, is flat, and in the form of a long and narrow rectangle. It is fastened to a blade holder  302  by its bottom edge. The blade holder  302  is attached to a pair of blade holder guides  306 , which are straight and parallel to the direction of the normal line of the surface of the blade  301 . The blade holder  302  is reciprocally movable along the blade holder guides  306 . That is, the blade  301  is reciprocally movable in the direction parallel to the normal line of the surface of the blade  301 . As will be evident from  FIG. 3 , the maintenance unit  107  is provided two blades  303 , which are fixed to the blade holder  302 . 
     When the blades  301  are not used for wiping the surface  201  of the recording head  101 , they are kept on standby in their standby positions  313 , which are at one end of the moving range of the blades  301 . As for the order, in terms of closeness to the standby position  313 , in which the abovementioned components of the maintenance unit  107  are position, the cleaning position  312 , blade cleaning means  303 , and cleaning liquid supplying means  303  are positioned in the listed order within the moving range of the blades  301 . The cleaning position  312  is the position in which the blades  301  are when they wipe the ink ejecting surface  201  of the recording head  101 . 
     As the maintenance operation for the recording head  101  is started, the recording head  101  is moved, along with the carriage  102 , to the cleaning position  312 , at which the maintenance unit  107  carries out its cleaning operation.  FIG. 3  shows the recording head  101  and carriage  102 , which are at the cleaning position  312 . The maintenance unit  107  is positioned so that as the blades  301  are moved, the ink ejecting surface  201  of the recording head  101  (which is in the cleaning position  312 ) comes into contact with the top edge portion of each blade  301 . Further, the blade cleaning means  303  and cleaning liquid supplying means  305  are positioned so that as the blade  301  are moved, the top edge portion of each blade  301  comes into contact with the blade cleaning means  303  and cleaning liquid supplying means  305 . 
     Further, the waste ink absorbing member  310  is positioned lower than the blade cleaning means  303 . In this embodiment, the waste ink absorbing member  310  is positioned directly below the blade cleaning means  303 . Further, the blade cleaning means  303  is in connection to a pair of conduits  304  which are tubular members for guiding the recovered contaminated ink to the waste ink absorbing member  310 . 
     The blade  301  is used to wipe away the ink, paper dust, and the like, which have adhered to the ink ejecting surface of the recording head  101 . The blade  301  is placed in contact with the ink ejecting surface  210  of the recording head  101  by the movement of the blade holder  302 , and then, is made to wipe the ink ejecting surface  201  of the recording head  101  by the further movement of the blade holder  302 . 
     The blade cleaning means  303 , which is a cleaner, removes the contaminated ink having adhered to the blade  301 , and then, collects (recovers) the contaminated ink as it removes the ink. “Contaminate ink” means the ink having adhered to the blade  301 , or the mixture of the ink having adhered to the blade  301  and the cleaning liquid (which will be described later). 
     Next, referring to  FIG. 4 , the structure of the blade cleaning means  303  will be described in detail. The broken lines in the drawing are for providing the phantom view of the interior of the blade cleaning means  303 . The blade cleaning means  303  is made up of an edge portion  401 , a contaminated ink recovering portion  402 , and a pair of joint portions  403 . The edge portion  401  is wide enough to contact the entirety of the cleaning edge portion of the blade  301  in terms of the lengthwise direction of the blade  301 . The contaminated ink recovering portion  402  (which hereafter will be referred to simply as recovery portion  402 ) is shaped like a cylindrical hollow column, the lateral wall of which is partially missing. It has grooves which are small enough to generate capillary force. It is attached to the edge portion  401 , and recovers the contaminated ink by its capillarity as the contaminated ink is scraped away from the blade  301 . The joint portions  403  are structured so that the contaminated ink recovered by the recovery portion  402  can pass through the joint portions  403 . Further, each joint portion  403  is provided with a protruding portion, which can be pressed into the ink guiding tube  304  to connect the joint portion  403  and ink guiding tube  304  to each other; the outward end of the joint portion  403  is connected to the ink guiding tube  304 , which is a contaminated ink guiding member. As described above, the recovery portion  402  of the blade cleaning means  303  is connected to the pair of conduits  304 , or recovered ink guiding tubes, so that the recovered contaminated ink flows through the joint portions  403  between the recovery portion and the recovered ink guiding tubes  304 . 
     As each of the abovementioned blades  301  moves, the blade  301  passes by the blade cleaning means  303 , with the top edge portion of the blade  301  remaining in contact with the edge portion  401 . Thus, the edge portion  401  scrapes the contaminated ink having adhered to the blades  301 , away from the blades  301 . Further, the contact pressure between each blade  301  and edge portion  401  can be increased by using an elastic substance, for example, rubber, as the material for the edge portion  401 . Increasing the contact pressure can increase the efficiency with which the contaminated ink having adhered to the blade  301  is scraped away from the blade  301 . 
     The grooves of the recovery portion  402  are structured so that they are greater in capillarity than the edge portion  401 . Therefore, it is possible for the contaminated ink to be recovered after being scraped away from the blades  301  by the edge portion  401 . 
     Referring to  FIG. 5 , the recovery portion  402  may be made up of multiple grooves. Providing the recovery portion  402  with multiple grooves makes it possible to more efficiently recover the contaminated ink after the contaminated ink is scraped away from the blades  301 . 
     Further, each joint portion  403  is structured to generate a greater amount of capillary force than the recovery portion  402  so that the contaminated ink is efficiently conveyed to the joint portions  403  after the contaminated ink is recovered by the recovery portion  402 . After the recovered contaminated ink is conveyed to the joint portions  403 , it flows through the ink guiding tube  304 , and then, is guided onto the waste ink absorbing member  310 , preventing thereby the problem that the contaminated ink collects on the blade cleaning means  304 . Therefore, the contaminated ink does not transferred back onto the blade  301  from the blade cleaning means  303 . 
     The recovery portion  402 , joint portions  403 , and guiding tubes  304  make up the ink removing means for removing the contaminated ink from the edge portion  401 . 
     Further, the cleaning liquid supplying means  305  shown in  FIG. 3  is provided with a supporting portion  503  for supporting the blade cleaning means  303 . The supporting portion  503  is at the end of the cleaning liquid supplying means  305 , on the side from which the blades  301  come into contact with the blade cleaning means  303 . It is in the supporting portion  503  that the joint portions  403  of the blade cleaning means  303  are fitted so that they are allowed to rotate by a preset angle while remaining fitted. 
     The blades  301  come into contact with the edge portion  401  of the blade cleaning means  303 , by being moved in the direction indicated by an arrow mark B in  FIG. 3 . Whether the blades  301  come into contact with the edge portion  401  or not, the edge portion  401  remains stationary, remaining in its preset position (which hereafter will be referred to as home position. Thus, while each blade  301  is in contact with the edge portion  401  when the edge portion  401  is in its home position, there is a substantial amount of contact pressure between them, and therefore, the edge portion  401  can effectively scrape the contaminated ink having adhered to the blades  301 , away from the blades  301 . On the other, as the blades  301  are moved in the opposite direction (in which blades  301  are moved to be returned to standby position  313 ) from the direction indicated by the arrow mark B, the blade cleaning means  303  rotates as if the joint portions  403  were their rotational axle; in other words, the blade cleaning means  303  rotates away (retreats) from its home position. As the blade cleaning means  303  retreats from its home position, the contact pressure between each blade  301  and blade cleaning means  303  becomes smaller. Thus, the contact pressure generated between each blade  301  and blade cleaning means  303  when the blade  301  is moved toward its standby position  313  is smaller than that when the blade  301  is moved for its cleaning. As soon as each blade  301  is moved past the blade cleaning means  303  toward its standby position  313 , the blade cleaning means  303 , which had rotated away from its blade cleaning position, automatically rotates back into its blade cleaning posture. As for the mechanism which allows the blade cleaning means  303  to revert into its blade cleaning posture, the weight of the blade cleaning means  303  itself can be utilized, or a spring or the like member may be provided to apply to the blade cleaning means  303 , such a force that is opposite in direction to the direction in which the blade cleaning means  303  is rotated by the blades  301  when the blades  301  are moved back into their standby positions. 
     As the blade cleaning means  303  is moved as described above, each of the ink guiding tubes  304  is rotationally moved as if it were a swing attached to the end of the supporting portion  503 . That is, the blade  301  in motion, and the edge portion  401  which is being swayed by the blade  301 , make up the means which causes the guiding tube  304  to sway. The swaying of the guiding tube  304  gives the contaminated ink in the guiding tube  304  centrifugal force which works in the direction to move the ink toward the exit side of the guiding tube  304 . Further, since the waste ink absorbing member  310  is directly below the blade cleaning means  303 , the contaminated ink in the ink guiding tube  304  is affected by the gravity which acts on the contaminated ink in the ink guiding tube  304 , in the direction to move the contaminated ink toward the exit side of the guiding tube  304 , contributing to the extraction of the contaminated ink from the ink guiding tube  304 . Further, the blade cleaning means  303  is structured so that the exit end of the ink guiding tube  304  is in contact with the waste ink absorbing member  310 , at least when the blade cleaning means  303  is on standby. 
     Further, the cleaning liquid supplying means  305 , shown in  FIG. 3 , which is a liquid supplying means, has a cleaning liquid storing portion  501 , which is in the cleaning liquid supplying means  305 . The surface of the cleaning liquid supplying means  305 , with which the blade  301  comes into contact, has a cleaning liquid outlet  502 , which is made up of a porous substance with capillarity. Thus, the cleaning liquid in the cleaning liquid storage portion  501  forms meniscus in the cleaning liquid outlet  502 , being thereby prevented from leaking through the cleaning liquid outlet  502 . As the blade  301  comes into contact with the cleaning liquid outlet  502 , the meniscuses having been formed in the cleaning liquid outlet  502  by the cleaning liquid are broken by the contact, allowing the cleaning liquid to flow out of the cleaning liquid storing portion  501  so that the blade  301  is coated with the cleaning liquid. 
     As long as the cleaning liquid outlet  502  can be supplied with the cleaning liquid, the storage portion  501  may be any storage portion. For example, it may be filled with a porous member, which is smaller in capillary force than the cleaning liquid outlet  501 , or may be a plain empty space. 
     It is desired that the cleaning liquid is one of those which can easily dissolve or disperse the ink having adhered to the ink ejecting surface  201  of the recording head  101 . Further, it is also desired that the primary ingredient of the cleaning liquid is a liquid which is lower in volatility than the ink. Employing one of such inks as those described above can improve the efficiency with which the ink ejecting surface  201  of the recording head  101  is wiped clean. 
     Further, the employment of a cleaning liquid which is low in volatility can prevents the contaminated ink from drying up after its adhesion to the blade  301 . In other words, it can keep the contaminated ink fluid after the adhesion of the contaminated ink to the blade  301 , making it thereby possible to draw the contaminated ink into the waste ink absorbing member  310  even when an ink which is higher in terms of durability (fastness) is used. As an example of cleaning liquid, such as the one described above, water solution of glycerin may be listed. Incidentally, when water solution of glycerin is used, the glycerin percentage is desired to be no less than 50%. Further, as the examples of ink which are high in durability (fastness), there are inks which contain pigment. 
     The waste ink absorbing member  310  is desired to be formed of a porous material capable of absorbing the contaminated ink. Further, the pores of the porous material for the waste ink absorbing member  310  are smaller in diameter than the internal diameter of the waste ink guiding tube  304 , in order to ensure that the waste ink absorbing member  310  is greater in capillary force than the ink guiding tube  304 , and therefore, the contaminated ink is efficiently drawing into the waste ink absorbing member  310  from the ink guiding tube  304 . 
     Further, the waste ink absorbing member  310  is desired not be water repellent; it is desired to have a certain amount of affinity for water. With the waste ink absorbing member  310  having a certain level affinity for water, the adjacencies of the waste ink absorbing member  310  is kept humid by the contaminated ink having been drawn into the waste ink absorbing member  310 . That is, the blade cleaning means  303 , which is above the waste ink absorbing member  310 , is kept in a humid environment. Therefore, the contaminated ink in the waste ink absorbing member  310  is better prevented from drying up. Therefore, the maintenance unit  107  in this embodiment is significantly greater in the level of fluidity with which the contaminated ink flows through the ink guiding tube  304  than a conventional maintenance unit, that is, a maintenance unit in accordance with the prior art. Therefore, the maintenance unit  107  in this embodiment can significantly more efficiently draw the contaminated ink into the waste ink absorbing member  310  than a conventional maintenance unit, even when an ink which is high in durability (fastness) is used. 
     Further, the waste ink absorbing member  310  is desired to be replaceable so that it can be ensured that the contaminated ink is efficiently absorbed away for a long period of time. Incidentally, it is desired that, if necessary, the waste ink absorbing member  310  is impregnated with a solvent capable of dissolving or dispersing the ink having increased in viscosity. With the waste ink absorbing member  310  impregnated with such a solvent, it is possible to prevent the waste ink absorbing member  310  from clogging up. 
     The capping means  308  is disposed below the recording head cleaning position  312  of the maintenance unit  107 . It is structured so that it can cover the entirety of the ink ejecting surface  201 . Further, the capping means  308  is in connection with the a suctioning means  309 , and one end of the suctioning means  309  is in connection with the waste ink absorbing member  310 . 
     In a case where a recording operation of the recording head  101  is suspended longer than a preset length of time, the ink ejecting surface  201  is placed in the “capped state”. The “capped state” means the state in which the ink ejecting surface  201  remains airtightly sealed by being entirely covered by the capping means  308 . Capping the ink ejecting surface  201  can ensure that the recording head  101  is prevented from being physically damaged, and also, the ink in each ink ejecting nozzle  202  of the recording head  101  is prevented from drying up. That is, the capping can prevent the ink ejecting nozzle  202  from clogging up. Further, while the ink ejecting surface  201  remains capped, the ink ejecting nozzle  202  may be forced to discharge the ink therein, by suctioning the ink ejecting nozzle  202  by the suctioning means  309 , in order to make the ink ejecting nozzle  202  discharge the air bubbles, high viscosity ink (body of ink, from which its volatile ingredients have evaporated), debris, etc., along with the ink. Described above is how the recording head  101  is maintained in terms of ink ejecting performance. The body of waste ink (which hereafter will be referred to simply as waste ink) having been discharged by the suctioning means  309  as described above, is eventually discharged into the waste ink absorbing member  310 . As described above, the waste ink absorbing member  310  can be utilized as a liquid storage portion for the waste ink. Integrating the member for storing the contaminated ink, and the member for storing the waste ink, into a single member as described above can simplify the maintenance unit  107  in structure. It is desired that this integration causes the contaminated ink and waste ink to mix with each other as little as possible, in order to ensure that the waste ink absorbing member  310  remains absorbent for a long time. This can be easily achieved by placing the discharging end of the ink guiding tube  304 , away from the outlet of the suctioning means  309 . Further, a part of the waste ink absorbing member  310  may be separated from the main portion of the waste ink absorbing member  310 . 
     It is possible that when ink is forcefully discharged by the suctioning means  309  as described above, the discharge ink will adheres to the ink ejecting surface  201  of the recording head  101 . Thus, it is desired that when this process of forcefully discharging ink is carried out, the above described process of wiping the ink ejecting surface  201  of the recording head  101  is also carried out so that the recording head  101  is better maintained. 
     Next, referring to  FIGS. 6A-6F , the flow of the process of wiping the ink ejecting surface  201  of the recording head  101  with the maintaining unit  107  will be described. The broken lines in the drawings represent the phantom view of the interior of the cleaning liquid outlet  502 . The process of wiping the ink ejecting surface  201  has: a standby step, a wiping step, a blade cleaning step, a cleaning liquid applying step, a swinging step, and a recovery step. 
     In the standby step, the blade  301  is kept on standby in the cleaning blade standby position  313  ( 6 A). When the blade  301  is in its standby position, the recording head  101  is recording an image, is being subjected to the operation for suctioning out the ink in the ink ejecting nozzles  202 , or remains capped. Also in this step, the cleaning end portion of the blade  301  remains coated with the cleaning liquid which was applied thereto in the preceding cleaning liquid applying step. 
     In the wiping step, the ink ejecting surface  201  of the recording head  101  is wiped by the blade  301  ( FIG. 6B ). More specifically, as a command for wiping the ink ejecting surface  201  is issued, the recording head  101  is moved to the ink ejecting surface cleaning position  312  in the maintenance unit  107  so that the ink ejecting surface  201  is positioned in the path of the blade  301 . Then, the blade holder  302  is moved. As the blade holder  302  is moved, the cleaning edge of the blade  301  glides across the ink ejecting surface  201  while remaining in contact with the ink ejecting surface  201 , wiping the ink ejecting surface  201 . Thus, when the recording head  101  is wiped next time, it is wiped with the clean blade  301 . 
     Further, the cleaning edge of the blade  301  is coated with the cleaning liquid. Therefore, the ink ejecting surface  201  is supplied with the cleaning liquid during the wiping step. Therefore, the contaminated ink on the ink ejecting surface  201  can be very effectively removed through the wiping step. As the wiping step is carried out, the mixture of the contaminated ink and cleaning liquid, which has been wiped away from the ink ejecting surface  201 , adheres to the blade  301 . 
     In the blade cleaning step, the contaminated ink having adhered to the blade  301  during the wiping step is recovered ( FIG. 6C ). More specifically, after the completion of the wiping step, the cleaning edge portion of the blade  301  is placed in contact with the edge portion  401  of the blade cleaning means  303 , and is moved toward the cleaning liquid supplying means  305  while being rubbed by the edge portion  401 . During this movement of the blade  301 , the edge portion  401  remains stationary in its home position, because the ink guiding tubes  304  have come into contact with the waste ink absorbing member  310 , being thereby prevented from rotating in the clockwise direction. Therefore, the contaminated ink having adhered to the blade  301  is scraped away by the edge portion  401  of the blade cleaning means  303 . The body of ink having just been scraped away from the blade  301  is recovered from the edge portion  401  by the recovery portion  402 , and is quickly guided into the ink guiding tubes  304  by the capillarity of the grooves of the recovery portion  402 . 
     In the cleaning liquid applying step, the cleaning liquid is applied to the edge portion of the blade  301  ( FIG. 6D ). More specifically, after the completion of the blade cleaning step, the blade  301  is continuously moved toward the cleaning liquid supplying means  305 , until the cleaning edge portion of the blade  301  comes into contact with the cleaning liquid outlet  502 , by which the cleaning edge portion of the blade  301  is to be coated with the cleaning liquid. In other words, the cleaning liquid applying step is carried out simply by moving the blade  301  straight forward. This is possible because the blade cleaning means  303  is between the recording head cleaning position  312  of the maintenance unit  107 , and the cleaning liquid supplying means  305 . 
     After the coating of the blade  301  with the cleaning liquid, the blade  301  is moved backward to be returned to its standby position  313 . 
     The swinging step is the step for making it easier to retract the blade  301  ( FIG. 6E ). More specifically, after the completion of the cleaning liquid applying step, the blade  301  is continuously moved backward, and is made to pass by the blade cleaning means  303  from the opposite direction from the direction in which it is made to pass by the blade cleaning means  303  in the blade cleaning step. During this backward movement of the blade  301  along the blade cleaning means  303 , the blade  301  continuously pushes up the edge portion  401  of the blade cleaning means  303 . The blade cleaning means  303  is structured so that it is allowed to rotate about the joint portions  403 , in the counterclockwise direction in  FIG. 6E . Thus, it does not occur that the blade  301  is subjected to a large amount of resistance from the blade cleaning means  303 . Therefore, the blade  301  can be easily retracted. During this step, the ink guiding tube  304  is rotated about its lengthwise end on the contaminated ink entrance side by the rotational movement of the blade cleaning means  303 . 
     After the contaminated ink is scraped away in the blade cleaning step, it is guided into the ink guiding tube  304  through the area with which the blade  301  does not come into contact. Therefore, it does not occur that the contaminated ink transfers back onto the blade  301  in the swinging step. 
     In the recovery step, the blade  301  retracts into its standby position  313  ( FIG. 6F ). More specifically, as the blade  301  separates from the edge portion  401  toward the end of the recovery step in which it is moved backward along the blade cleaning means  303 , the blade cleaning means  303  and ink guiding tube  304  rotate, due to their own weight, in the opposite direction from the direction in which they were rotated in the swinging step. As a result, they regain the natural posture, in which they remain stationary, with the bottom end of each ink guiding tube  304  remaining in contact with the waste ink absorbing member  310 . That is, in the swinging step and recovery step, each of the ink guiding tubes  304  swings about its lengthwise end, from which the contaminated ink entrances the ink guiding tube  304 . This swinging of the ink guiding tube  304  subjects the contaminated ink in the ink guiding tube  304  to centrifugal force, which works in the direction to guide the ink out of the ink guiding tube  304 , adding to the efficiency with which the contaminated ink is guided into the waste ink absorbing member  310 . 
     As the retraction of the blade  301  continues, the blade  301  eventually returns to its standby position. Also in this step, the recording head  101  is set aside from the path of the blade  301 , in order to prevent the blade  301  from coming into contact with the recording head  101 . As the blade  301  returns to its standby position  313 , the maintenance unit  107  becomes ready for cleaning, and remains on standby. 
     (Embodiment 1—Another Embodiment of Maintenance Unit) 
     Next, another embodiment of the maintenance unit will be described.  FIG. 7  is a perspective view of the maintenance unit in another embodiment of the present invention, and shows the structure of the unit. The maintenance unit in this embodiment has a pair of blades  301 , a blade cleaning means  303 , a cleaning liquid supplying means  305 , and a waste ink absorbing means  310 . These components, except for one of them, are similar in structure to the counterparts of the maintenance unit  107  shown in  FIG. 3 . The one component which is different from the counterpart shown in  FIG. 3  is the ink guiding member for providing the maintenance unit with the ink path for guiding the contaminated ink recovered by the blade cleaning means  303 , into the waste ink absorbing member  310 . 
     In this embodiment, the maintenance unit is provided with a pair of fibrous members  311  as the members for guiding the contaminated ink into the waste ink absorbing member  310 . The fibrous members  311  are attached to a pair of joint portions  503 , one for one, with which the blade cleaning means  303  is provided. The joint portion  503  is a piece of hollow tube. More specifically, the fibrous member  311  is connected to the recovery portion  402  of the blade cleaning means  303 , with the interposition of the joint portion  503  between the recovery portion  402  and fibrous member  311 , so that the liquid flows from the blade cleaning means  303  to the fibrous member  311  through the joint portion  503 . Thus, the contaminated ink recovered by the recovery portion  402  of the blade cleaning means  303  is transmitted to the fibrous member  311  through the joint portion  503 . 
     Like the above described ink guiding tube  304 , the fibrous member  311  guides the contaminated ink, which it has received from the joint portion  503 , into the waste ink absorbing member  310 . The fibrous member  311  is desired to have a certain level of wettability so that it can efficiently guide the contaminated ink into the waste ink absorbing member  310 . 
     Further, since the waste ink absorbing member  310  is directly below the blade cleaning means  303 , the contaminated ink in the fibrous member  311  is effectively guided onto the waste ink absorbing member  310  by gravity. 
     The maintenance unit in this embodiment may be structured so that the fibrous member  311  is made to swing like the ink guiding tubes  304  in the first embodiment, in order to raise the level of efficiency with which the contaminated ink is guided out of the fibrous members  311 . 
     In the above, a couple preferred embodiments of the present invention have been concretely described. However, these embodiments are not intended to limit the present invention in scope. That is, it is needless to say that the preferred embodiments are variously modifiable as long as the modifications do not contradict the gist of the present invention. For example, the structural components in the preceding embodiments of the present invention can be modified in shape, positioning, etc., as long as the modifications are compatible with the present invention. 
     In the preceding embodiments of the present invention, the maintenance unit  107  is provided with two blades  301 . However, the blade count may be one, or three or more. That is, the blade count may be changed in accordance with the shape, performance, etc., of the recording head  101 . Further, the shape of the blade  301  does not matter as long as the blade  301  can efficiently wipe the ink ejecting surface  201  of the recording head  101 , and also, can efficiently remove the contaminated ink having adhered to the ink ejecting surface  201 . 
     Further, regarding the shape of the recovery portion  402  of the blade cleaning means  303 , the recovery portion  402  does not need to be shaped like a piece of hollow column, a part of which is missing. That is, the shape of the recovery portion  402  may be any as long as the recovery portion  402  can move the contaminated ink to the ink guiding tubes, or fibrous members, after the contaminated ink is scraped away from the blades  301  by the edge portion  401 . 
     Further, in these embodiments, the blade cleaning means  303  is supported by the cleaning liquid supplying means  305 . However, as long as the blade cleaning means  303  is positioned so that it can come into contact with the blades  301 , it is not mandatory that the blade cleaning means  303  is supported by the cleaning liquid supplying means  305 . 
     While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims. 
     This application claims priority from Japanese Patent Application No. 315819/2007 filed Dec. 6, 2007, which is hereby incorporated by reference.

Technology Classification (CPC): 1