Patent Publication Number: US-8113624-B2

Title: Image recording apparatus that prevents deterioration of an elastic blade

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Patent Application No. 2008-211307, which was filed on Aug. 20, 2008, the disclosure of which is herein incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image recording apparatus which records an image on a recording medium. 
     2. Discussion of Related Art 
     US 2006/0170727 A1 (corresponding to JP 2006-212863 A) (hereinafter, referred to as “Patent Document 1”) discloses an inkjet recording apparatus which includes a wiping device having an elastic blade that is located on one of opposite sides of an inkjet recording head that is vertically movable. In the inkjet recording apparatus, after the recording head is moved upward to a position where a vicinity of an edge of the elastic blade is contactable with the nozzle surface of the recording head, the wiping device is moved from the one of opposite sides of the recording head along the nozzle surface, so that the elastic blade wipes a nozzle surface of the inkjet recording head. 
     However, in the inkjet recording apparatus disclosed in Patent Document 1, when a wiping operation begins, the elastic blade is moved from the one side of the recording head along the nozzle surface. Therefore, the elastic blade comes into contact with one of end portions of the nozzle surface, i.e., one of corners of the recording head every time the wiping operation is performed, so that the elastic blade is deteriorated at an early point. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an image recording apparatus that prevents an early deterioration of the blade caused by contacting the end portion of the nozzle surface. 
     According to the present invention, there is provided an image recording apparatus comprising: a recording head having an ejection surface which includes an ejection area that has a plurality of ejection openings for ejecting liquid and non-ejection areas having no ejection openings that are provided on opposite ends of the ejection area in one direction and on a same plane with the ejection area; an elastic blade which is configured to wipe the ejection surface; a first moving device which is configured to move the blade and the ejection surface relative to each other in the one direction; a second moving device which is configured to move the blade and the ejection surface relative to each other in a direction perpendicular to the ejection surface; and a controller which controls the first moving device and the second moving device. During a first predetermined period of time that includes a point of time when the blade comes into contact with the ejection surface, the controller controls the second moving device so as to cause a relative movement of the blade and the ejection surface in the direction perpendicular to the ejection surface and in a direction in which the blade relatively moves toward the ejection surface and controls the first moving device so as to cause the relative movement of the blade to the ejection surface in the one direction, and during a second predetermined period of time that comes after the first predetermined period of time, the controller controls the second moving device such that the blade is in contact with the ejection surface and the first moving device such that the blade wipes at least the ejection area by a relative movement of the blade to the ejection surface in the one direction. 
     In the image recording apparatus, the blade is prevented from (compression) buckling when the blade contacts the ejection surface, and also prevented from deterioration of the blade in early stage caused by contacting the end portion of the ejection surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and optional objects, features, and advantages of the present invention will be better understood by reading the following detailed description of the preferred embodiments of the invention when considered in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view schematically showing an inkjet printer as one embodiment to which the present invention is applied; 
         FIG. 2  is a side view schematically showing the inkjet printer; 
         FIG. 3  is a bottom view of four inkjet heads of the inkjet printer shown in  FIG. 1 ; 
         FIG. 4  is a block diagram showing a structure of a controller of the inkjet printer shown in  FIG. 1 ; and 
         FIG. 5  is an illustrative view for explaining process steps of a wiping operation:  FIG. 5A  shows a state of the inkjet heads and a blade when the blade is positioned at a wiping start position;  FIG. 5B  shows another state thereof at an end of a first predetermined period of time;  FIG. 5C  shows another state thereof at an end of a second predetermined period of time; and  FIG. 5D  shows another state thereof at an end of a third predetermined period of time when the blade is positioned at a wiping end position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, there will be described preferred embodiments of the present invention with reference to the drawings. As shown in  FIG. 1 , an inkjet printer  1  as one embodiment of an image recording apparatus to which the present invention is applied is a color inkjet printer that includes four inkjet heads (or printheads)  2  as recording heads. In the inkjet printer  1 , there is provided a feeding device  40  that feeds a recording sheet P as a recording medium. The inkjet printer  1  further includes a controller  100  that controls various operations of the inkjet printer  1 . 
     The feeding device  40  includes a pair of belt rollers  41   a ,  41   b  and an endless feed belt  42  which is wound on the pair of belt rollers  41   a ,  41   b . The belt rollers  41   a ,  41   b  extend in a main scanning direction and are spaced from each other horizontally in a sub-scanning direction that is perpendicular to the main scanning direction. When a feed motor  110  (shown in  FIG. 4 ) is driven by controlling of the controller  100 , one belt roller  41   a  is rotated in a direction that is indicated by an arrow A in  FIG. 1 . As the belt roller  41   a  is rotated, the feed belt  42  is circulated in the same direction indicated by the arrow A in  FIG. 1 . In this embodiment, an area of an outer circumferential surface of the feed belt  42  that faces upward functions as a feeding surface on which the recording sheet P is fed in a sheet feed direction B or a direction that extends from a front side to a back side in  FIG. 1 . The other belt roller  41   b  is a driven roller that is rotated by a circulation of the feed belt  42 . 
     In the present embodiment, the sub-scanning direction is a direction that extends parallel to the sheet feed direction B of the recording sheet P by the feeding device  40 , and the main scanning direction as one direction is a direction that extends horizontally and that is perpendicular to the sub-scanning direction or a left-right direction in  FIG. 1 . 
     The feeding device  40  also includes a plurality of nip rollers  43  that are coaxially connected to each other in the main scanning direction. The plurality of nip rollers  43  are rotatably supported by a shaft  43   a , and the shaft  43   a  is biased downward by a biasing device (not shown) such that the nip rollers  43  are pressed against the feeding surface of the feed belt  42 . Each nip roller  43  is a driven roller, similar to the belt roller  41   b , which is rotated by the circulation of the feed belt  42 . 
     The recording sheet P is fed by the feeding device  40  as follows. When a leading end of the recording sheet P reaches an area that is located between the nip rollers  43  and the feed belt  42 , the recording sheet P is nipped by the nip rollers  43  and the feed belt  42  and fed in the sheet feed direction B with the circulation of the feed belt  42 . The recording sheet P is fed in the sheet feed direction B with being supported by the feeding surface of the feed belt  42  to a position where the recording sheet P is opposed to the ejection surface  3  of each of the four inkjet heads  2 . 
     The four inkjet heads  2  correspond to four colors of inks (magenta, yellow, cyan, and black), and as shown in  FIGS. 1 and 2 , each inkjet head  2  has a generally parallelepiped shape extending in the main scanning direction. The four inkjet heads  2  are arranged in the sub-scanning direction so as to be spaced apart at predetermined intervals therebetween and are fixed to a frame (not shown). In other words, the inkjet printer  1  in the present embodiment is a line-type printer. 
     Each inkjet head  2  includes a reservoir unit  5  for temporarily accommodating ink that is supplied from an ink tank (not shown), a support plate  6  that is fixed to a bottom surface of the reservoir unit  5 , and a head body  7  that is fixed to a bottom surface of the support plate  6 . 
     The support plate  6  is a plate-like member having a length or a dimension in the main scanning direction that is longer than that of each of the reservoir unit  5  and the head body  7  and is fixed to the frame (not shown) at opposite ends thereof in the main scanning direction. In the support plate  6 , there is formed a communication passage through which a passage of the reservoir unit  5  and a passage of the head body  7  are communicated with each other, so that ink accommodated in the reservoir unit  5  flows into the head body  7  through the communication passage. 
     The ejection surface  3  that is a bottom surface of the head body  7  is a horizontal and flat surface, and the ejection surface  3  is opposed to and parallel to the feeding surface of the feed belt  42 . As shown in  FIG. 3 , the ejection surface  3  includes (1) an ejection area  3   a  that includes a plurality of nozzle rows in which a plurality of nozzles  4  as ejection openings for ejecting ink as liquid are arranged in the main scanning direction and that is a rectangular area which extends in the main scanning direction with a width in the sub-scanning direction identical to that of the head body  7 , and (2) non-ejection areas  3   b ,  3   c  without ejection openings that are provided on opposite ends of the ejection area  3   a  in the main scanning direction and that are on a same plane with the ejection area  3   a . In the present embodiment, one of the opposite non-ejection areas  3   b ,  3   c  that is located closer to a blade  50  that is positioned at a retracted position (described later) is the non-ejection area  3   b , while the other that is located apart or farther from the blade  50  at the retracted position is the non-ejection area  3   c.    
     When the recording sheet P passes through an area that is opposed to the ejection area  3   a  while being fed by the feeding device  40 , each inkjet head  2  is controlled by the controller  100  such that droplets of the ink of each color are ejected in order from each of the nozzles  4  in each ejection surface  3  toward the recording sheet P, and an image is then formed on a desired position or area of the recording sheet P. Then, the recording sheet is discharged onto a sheet-discharge tray, not shown, by the feeding device  40 . 
     As shown in  FIG. 1 , in the inkjet printer  1 , there is disposed a head moving device  10  as a second moving device that moves the frame to which the four inkjet heads  2  are fixed in a vertical direction perpendicular to the ejection surface  3  (a direction C) or in a direction perpendicular to the main scanning direction and the sub-scanning direction. As the frame is moved up and down in the vertical direction, the inkjet heads  2  are also moved up and down in the vertical direction. 
     When the controller  100  controls the head moving device  10  to move the inkjet heads  2  in the vertical direction or in the direction C, a clearance between the feeding surface of the feed belt  42  and the ejection surface  3  is changed. As shown in  FIG. 2 , the four inkjet heads  2  are normally positioned at a printing (recording) position, a lowermost position within a movable range of the head moving device  10 , where the inkjet heads  2  performs a printing operation by ejecting ink toward the recording sheet P. When the inkjet heads  2  are positioned at the printing position, a small clearance is made between the feeding surface and the ejection surface  3  of the inkjet heads  2 . When a wiping operation is performed, the inkjet heads  2  are moved by the head moving device  10  to a position that is higher than the printing position. 
     On one of opposite sides of the feeding device  40  in the main scanning direction, there is disposed a moving plate  44  as a support member. The moving plate  44  is a plate that supports the blade  50  for wiping ink stuck or adhered to the ejection surface  3  and is arranged to be reciprocateable in the main scanning direction. One of opposite ends of the moving plate  44  in the sub-scanning direction is attached to a drive belt  49 , as described later. 
     The blade  50  is made of an elastic material such as a resin or a rubber, and a thickness of the blade  50  in the main scanning direction is made relatively small. One of opposite end portions of the blade  50  or one end portion thereof is contactable with the ejection surface  3 , and the other end portion of the blade  50  that is closer to the moving plate  44  is fixed to the moving plate  44 . Further, a length of the blade  50  in the sub-scanning direction is slightly longer than a total length of the four inkjet heads  2  in the sub-scanning direction. Therefore, as the blade  50  is moved in the main scanning direction in a state in which the blade  50  is in contact with the ejection surface  3 , the four ejection surfaces  3  of the four inkjet heads  2  can be wiped at once by the blade  50 . 
     The inkjet printer  1  further includes a drive device  46  as a first moving device by which the moving plate  44  is reciprocated in the main scanning direction. The drive device  46  includes a driven roller  47 , a driving roller  48 , a drive belt  49  and a drive motor  120  (shown in  FIG. 4 ) for driving the driving roller  48 . The driven roller  47  and the driving roller  48  are spaced apart from each other horizontally and in the main scanning direction and are disposed to be rotatable about a rotation axis extending in the sub-scanning direction. The drive belt  49  is wound on the driven roller  47  and the driving roller  48 . 
     In the above-mentioned drive device  46 , when the controller  100  controls the drive motor  120  to rotate the driving roller  48  in a certain direction or in a clockwise direction in  FIG. 1 , the drive belt  49  is circulated. Thus, the moving plate  44  is moved in the main scanning direction from the retracted position that is located on the one side of the feeding device  40  in the main scanning direction, through a wiping start position where the moving plate  44  is opposed to the non-ejection area  3   b , to a wiping end position where the moving plate  44  is opposed to the non-ejection area  3   c.    
     On the other hand, when the controller  100  controls the drive motor  120  to rotate the driving roller  48  in an opposite direction to the certain direction or in a counterclockwise direction in  FIG. 1 , the moving plate  44  is moved in the main scanning direction from the wiping end position, through the wiping start position, to the retracted position. As mentioned above, when the moving plate  44  is moved in the main scanning direction in the state in which the blade  50  is in contact with the ejection surface  3 , the blade  50  is moved in the main scanning direction while being in contact with the ejection surface  3 , so that the blade  50  wipes off ink stuck to the ejection surface  3 . 
     Hereinafter, the controller  100  will be described. The controller  100  mainly consists of, e.g., a general-purpose personal computer (PC). The PC includes a CPU (Central Processing Unit) as an arithmetic processing unit, a ROM (Read Only Memory) where control programs that are executed by the CPU and data that are used in the control programs are stored, a RAM (Random Access Memory) for temporarily storing data when implementing programs and hardware including a hard disk. In the hard disk, various sorts of software are stored, including programs for controlling operations of the inkjet printer  1 . The controller  100  controls the inkjet heads  2 , the head moving device  10 , the feed motor  110  and the drive motor  120 . 
     The wiping operation of the ejection surface  3  performed by the blade  50  will be described with reference to  FIGS. 5A through 5D . First, when the wiping operation is performed, as shown in  FIG. 5A , the controller  100  controls the head moving device  10  such that the four inkjet heads  2  that are positioned at the printing position moves up to an X position that is higher than a height position of an edge of the one of the opposite end portions of the blade  50 . The X position is a height position of respective ejection surfaces  3  of the four inkjet heads  2  at a beginning of the wiping operation. Then, the controller  100  controls the drive motor  120  to move the blade  50  from the retracted position to the wiping start position in the main scanning direction. As shown in  FIG. 5A , a first predetermined period of time begins after the one end portion of the blade  50  and the non-ejection area  3   b  are spaced apart from each other and are opposed to each other. 
     Next, as shown in  FIG. 5B , during the first predetermined period of time, the controller  100  controls the head moving device  10  such that the four inkjet heads  2  are constantly moved down in the vertical direction, while the controller  100  controls the drive motor  120  such that the blade  50  is constantly moved in the main scanning direction. Thus, the blade  50  gradually moves closer to the non-ejection area  3   b  in an oblique (inclined) direction and then contacts the non-ejection area  3   b  from the oblique direction. The first predetermined period of time is a period of time including a point of time when the blade  50  contacts the non-ejection area  3   b  after relatively moving from the wiping start position and until before the blade  50  contacts the ejection area  3   a . In other words, at an end of the first predetermined period of time, the blade  50  is in contact with the non-ejection area  3   b . Further, because the four inkjet heads  2  are constantly moved down during the first predetermined period of time, the inkjet heads  2  are moved down even after the point of time when the blade  50  comes into contact with the non-ejection area  3   b . Therefore, as shown in  FIG. 5B , at the end of the first predetermined period of time, the blade  50  is in contact with the non-ejection area  3   b  in a state in which the blade  50  is bent, so that the blade  50  can certainly be in contact with the non-ejection area  3   b.    
     Then, as shown in  FIG. 5C , during a second predetermined period of time that comes after the first predetermined period of time and that is a period of time ranging from the end of the first predetermined period of time to a point of time when the blade  50  passes over one of opposite ends of the ejection area  3   a  in the main scanning direction that is closer to the non-ejection area  3   c  after passing through the ejection area  3   a  in the main scanning direction, the controller  100  controls the head moving device  10  such that the four inkjet heads  2  are constantly kept from moving in the vertical direction and controls the drive motor  120  such that the blade  50  constantly moves in the main scanning direction. Accordingly, the blade  50  moves in the main scanning direction in a state of being in contact with the ejection surface  3  so as to wipe ink that is stuck to the ejection surface  3 . More specifically, at a beginning of the second predetermined period of time, the blade  50  is in contact with the non-ejection area  3   b , and then, the blade  50  is moved by the drive motor  120  in the main scanning direction so as to contact a whole range of the ejection area  3   a  in the main scanning direction. After that, the blade  50  passes over the one end of the ejection surface  3  and then contacts the non-ejection area  3   c . Therefore, at an end of the second predetermined period of time, the blade  50  is in contact with the non-ejection area  3   c . Accordingly, the blade  50  can wipe the ink that is stuck to a whole area of the ejection area  3   a.    
     In the present embodiment, the controller  100  controls the drive motor  120  so as to move the blade  50  in the main scanning direction at a speed during the first predetermined period of time that is slower than that during the second predetermined period of time. This is because a difference between an actual moving speed of the blade  50  in the main scanning direction during the first predetermined period of time and a desired moving speed thereof during the first predetermined period of time (or a deviation in the actual moving speed of the blade  50  during the first predetermined period of time from the desired moving speed thereof during the first predetermined period of time) can be minimized, and an offset amount of a contact position where the blade  50  contacts the non-ejection area  3   b  of the ejection surface  3  in the main scanning direction can be minimized, so that the blade  50  can certainly come into contact with the non-ejection area  3   b . Further, during the second predetermined period of time when the wiping operation is performed after the first predetermined period of time, the moving speed of the blade  50  in the main scanning direction is made faster than that during the first predetermined period of time, so that the wiping operation can be performed quickly. Moreover, since, during the wiping operation, the blade  50  and the moving plate  44  are movable in the main scanning direction only within an area in which the blade  50  is opposed to the ejection surface  3 , a movable area of the blade  50  in the main scanning direction can be made small and the wiping operation can be performed more quickly. Furthermore, during the second predetermined period of time, the controller  100  controls the head moving device  10  such that the four inkjet heads  2  are constantly kept from moving in the vertical direction, so that the blade  50  can be in contact with the ejection surface  3  (the ejection area  3   a  and the non-ejection areas  3   b ,  3   c ) at a constant force, leading to stabilizing of ink wiping performance. 
     As shown in  FIG. 5D , during a third predetermined period of time after the second predetermined period of time, ranging from the end of the second predetermined period of time to the point of time when the blade  50  is spaced apart from the non-ejection area  3   c  and opposed thereto after moving away from the non-ejection area  3   c , the controller  110  controls the head moving device  10  such that the four inkjet heads  2  constantly moves up to the X position and the drive motor  120  such that the blade  50  constantly moves in the main scanning direction to the wiping end position. In this case, the blade  50  is gradually moved away from the non-ejection area  3   c . Though a large amount of ink is stuck to the blade  50  after the wiping operation of the ejection area  3   a , because the blade  50  is gradually moved away from the non-ejection area  3   c , it can be prevented that ink is splashed. The third predetermined period of time is a period of time including a point of time when the blade  50  relatively moves away from the non-ejection area  3   c , ranging from a point of time when the blade  50  is in contact with the non-ejection area  3   c  after passing through the ejection area  3   a  to the point of time when the blade  50  is spaced apart from the non-ejection area  3   c  and opposed thereto after moving away from the non-ejection area  3   c.    
     In the present embodiment, the controller  100  controls the drive motor  120  so as to move the blade  50  in the main scanning direction at a speed during the third predetermined period of time that is slower than that during the second predetermined period of time. This is because a difference between an actual moving speed of the blade  50  in the main scanning direction during the third predetermined period of time and a desired moving speed thereof during the third predetermined period of time (or a deviation in the actual moving speed of the blade  50  during the third predetermined period of time from the desired moving speed thereof during the third predetermined period of time) can be reduced, and an offset amount of a separating (moving-away) position in the main scanning direction where the blade  50  relatively moves away from the ejection surface  3  can be minimized, so that the blade  50  can certainly be moved away from the ejection surface  3  within the non-ejection area  3   c  in the main scanning direction. The controller  100  also controls the drive motor  120  so as to move the blade  50  in the main scanning direction at the speed during the third predetermined period of time that is identical with that during the first predetermined period of time. Therefore, the moving speed of the blade  50  can be easily controlled by the controller  100  at two moving speeds of the blade  50 , i.e., the moving speed during the first predetermined period of time and during the third predetermined period of time, and the moving speed during the second predetermined period of time. 
     In the above-described inkjet printer  1 , since the blade  50  gradually moves closer to the ejection surface  3  in the oblique direction and then contacts the ejection surface  3 , the blade  50  is prevented from compression buckling when the blade  50  contacts the ejection surface  3 , and also prevented from deterioration in early stage caused by contacting end portions of the ejection surface  3 . More precisely, because, during the first predetermined period of time, the controller  100  controls the head moving device  10  such that the four inkjet heads  2  constantly moves down in the vertical direction, and the drive motor  120  such that the blade  50  constantly moves in the main scanning direction, the blade  50  gradually moves closer to the non-ejection area  3   b  in the oblique direction and then contacts the same  3   b , so that the blade  50  is prevented from compression buckling when contacting the ejection surface  3 . Further, since a position of the blade  50  shown in  FIG. 5A  is the wiping start position of the blade  50 , the blade  50  does not contact one corner of each inkjet head  2  (one of opposite end portions of the ejection surface  3  that is closer to the non-ejection area  3   b ), so that early deterioration of the blade  50  can be prevented. Furthermore, since a position of the blade  50  shown in  FIG. 5D  is the wiping end position, the blade  50  does not contact the other corner of each inkjet head  2  (the other end portion of the ejection surface  3  that is closer to the non-ejection area  3   c ), so that early deterioration of the blade  50  can be further prevented. 
     The present invention is not limited to the present embodiment. It is to be understood that the present invention may be embodied with various changes and modifications that may occur to a person skilled in the art, without departing from the spirit and scope of the invention defined in the appended claims. 
     In the illustrated embodiment, the blade  50  has a length that is slightly longer than a total length of the four inkjet heads  2  in the sub-scanning direction, so that the blade  50  can wipe the four ejection surfaces  3  of the four inkjet heads  2  at once. However, four blades  50  may be provided corresponding to the four inkjet heads  2 . 
     In the illustrated embodiment, the inkjet heads  2  are movable in the vertical direction by the head moving device  10  and the blade  50  is movable in the main scanning direction by the drive device  46 . However, the inkjet heads  2  and the blade  50  are movable relative to each other in the vertical direction and in the main scanning direction, and either of the inkjet heads  2  and the blade  50  may be relatively movable in the vertical direction and in the main scanning direction. For example, the inkjet heads  2  may be fixedly provided, while the blade  50  may be movable in the main scanning direction by the drive device  46  and in the vertical direction by a moving device that is newly disposed. On the contrary, the blade  50  may be fixedly provided, while the inkjet heads  2  may be movable in the vertical direction by the head moving device  10  and in the main scanning direction by a drive device that is newly disposed. 
     In the illustrated embodiment, the moving speed of the blade  50  in the main scanning direction is variable by control of the controller  100 . However, the moving speed of the blade  50  may be always kept constant, so that the controller  100  can easily control the moving speed of the blade  50 . 
     In the illustrated embodiment, during the first predetermined period of time, the controller  100  controls the head moving device  10  such that the four inkjet heads  2  constantly moves down in the vertical direction, and controls the drive motor  120  such that the blade  50  constantly moves in the main scanning direction. However, it is satisfactory that the four inkjet heads  2  and the blade  50  are moved at least at the point of time during the first predetermined period of time when the blade  50  comes into contact with the non-ejection area  3   b . Therefore, during another period of time except the above-mentioned point of time within the first predetermined period of time, at least either of the four inkjet heads  2  and the blade  50  may be prevented from moving. Further, as mentioned above, in the case where the head moving device  10  and the drive motor  120  are constantly operated during the first predetermined period of time, it can be considered that another period of time when at least one of the four inkjet heads  2  and the blade  50  is prevented from moving is a period of time outside the first predetermined period of time. 
     Furthermore, in the illustrated embodiment, at the end of the first predetermined period of time, the blade is in contact with the non-ejection area  3   b  of the ejection surface  3 . Instead of this, the blade  50  may be in contact with the ejection area  3   a  of the ejection surface  3  at the end of the first predetermined period of time. In this case, it can be considered that, during a period of time from a point of time when the blade  50  is moved from the non-ejection area  3   b  to the ejection area  3   a  in the main scanning direction to the end of the first predetermined period of time, as far as the blade  50  is in contact with the ejection surface  3 , one of opposite end portions of the ejection area  3   a  in the main scanning direction that is closer to the non-ejection area  3   b  is wiped. 
     Though, in the illustrated embodiment, the end of the first predetermined period of time is considered as the beginning of the second predetermined period of time, the second predetermined period of time may begin at any time after the end of the first predetermined period of time. There may be provided a period of time as an interval of time between the first predetermined period of time and the second predetermined period of time, when the drive device  46  and the head moving device  10  are kept from operation. 
     Furthermore, in the illustrated embodiment, the controller  100  controls the head moving device  10  during the second predetermined period of time such that the four inkjet heads  2  are constantly kept from moving in the vertical direction. Instead of this, the four inkjet heads  2  may be moved in the vertical direction at least during a certain period of time within the second predetermined period of time. For example, the controller  100  may control the head moving device  10  during the second predetermined period of time such that the inkjet heads  2  are moved up or down at a small distance. In this case, during the second predetermined period of time, as far as the blade  50  is in contact with the ejection surface  3 , the four inkjet heads  2  can be moved in the vertical direction. 
     In the illustrated embodiment, at the end of the second predetermined period of time, the blade  50  is in contact with the non-ejection area  3   c  of the ejection surface  3 . Instead of this, the blade  50  may be in contact with the ejection area  3   a  of the ejection surface  3  at the end of the second predetermined period of time. In this case, it can be considered that, during a period of time from the end of the second predetermined period of time until when the blade  50  is moved from the ejection area  3   a  to the non-ejection area  3   c , as far as the blade  50  is in contact with the ejection surface  3 , the other end portion of the ejection area  3   a  in the main scanning direction that is closer to the non-ejection area  3   c  is wiped. 
     In the illustrated embodiment, during the third predetermined period of time, the controller  100  controls the head moving device  10  such that the four inkjet heads  2  are constantly moved up in the vertical direction, and controls the drive motor  120  such that the blade  50  is constantly moved in the main scanning direction. However, it is satisfactory that the four inkjet heads  2  are moved in the vertical direction at least at the point of time within the third predetermined period of time when the blade  50  is moved away from the ejection surface  3 . Therefore, during another period of time except the above-mentioned point of time within the third predetermined period of time, at least either of the four inkjet heads  2  and the blade  50  may be prevented from moving. Further, as mentioned above, in the case where the head moving device  10  and the drive motor  120  are constantly operated during the third predetermined period of time, it can be considered that another period of time when at least one of the four inkjet heads  2  and the blade  50  are prevented from moving is a period of time outside the third predetermined period of time. 
     The image recording apparatus to which the present invention is applied is, not limited to the line-type printer, applicable to a serial-type printer whose head is reciprocateable, and also, not limited to the printer, applicable to a facsimile, a copier and so forth.