Patent Publication Number: US-2023150265-A1

Title: Liquid discharge apparatus and wiper used in liquid discharge apparatus

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from Japanese Patent Application No. 2021-185042 filed on Nov. 12, 2021. The entire content of the priority application is incorporated herein by reference. 
     BACKGROUND ART 
     A certain publicly known liquid discharge apparatus is provided with a head, a wiper which makes contact with a nozzle surface of the head and which wipes the nozzle surface, and a spring applying a force in an opposite direction to a restoring force, of the wiper, by which the wiper deformed by the contact with the nozzle surface of the head attempts to be restored to the original shape thereof, so as to weaken the restoring force. The spring is used so as to weaken the restoring force of the wipe, and to thereby suppress a restoring speed by which the wiper is restored, which in turn prevents an ink adhered to a forward end (tip end) of the wiper from scattering. 
     DESCRIPTION 
     In the publicly known liquid discharge apparatus, even in a case that the forward end of the wiper makes contact with the nozzle surface of the head and wipes the nozzle surface, the spring pulls the wiper. Accordingly, a pressure generated in a case that the wiper makes contact with the nozzle surface is weakened as compared with a case that the spring is not provided, which in turn lowers the wiping performance of the wiper. 
     An object of the present disclosure is to provide a technique of suppressing any lowering in the wiping performance of the wiper while suppressing the scattering of the ink adhered to the forward end of the wiper. 
     According to an aspect of the present disclosure, there is provided a liquid discharge apparatus including: a head; a wiper; and a driving part. The head includes a lower surface including a nozzle surface in which a nozzle is opened. The wiper is configured to make contact with the nozzle surface of the head and to wipe the nozzle surface. The driving part is configured to drive at least one of the wiper and the head so as to cause the wiper to move relative to the head toward one side in a wiping direction in a state that the wiper makes contact with the nozzle surface. The wiper includes: a wiper body including a wiping part configured to wipe the nozzle surface; and a projection projecting from the wiper body toward the other side in the wiping direction. After the wiping part of the wiper body is separated from an end part on the one side in the wiping direction of the nozzle surface, the projection is configured to make contact with the lower surface of the head. 
     In the above-described configuration, the projection projects from the wiper body toward the other side in the wiping direction. Accordingly, while the wiper is (being) moved toward the one side in the wiping direction so that only the wiping part of the wiper body wipes the nozzle surface of the head, there is not any fear that the projection might make contact with the lower surface of the head and that the wiping performance of the wiping part might be lowered thereby. Further, the projection is configured to make contact with the lower surface of the head after the wiping part of the wiper body is separated from the end part on the one side in the wiping direction of the nozzle surface. With this, the projection is capable of suppressing the restoring force, of the wiper, by which the deformation of the wiper body is restored, after the wiping part of the wiper body is separated from the nozzle surface. Accordingly, it is possible to suppress the restoring speed of the wiper body and to thereby suppress the scattering of the ink adhered to the wiping part of the wiper body. Further, there is no need to separately provide a member different from the wiper in order to suppress the restoring force of the wiper body. With this, is it possible to suppress the manufacturing cost of the liquid discharge apparatus. Furthermore, the projection does not affect the deformation of the wiper body in a case that the wiper body wipes the nozzle surface. Accordingly, even in a case that the projection is formed in order to suppress the restoring force of the wiper body, there is no such a fear that the wiping performance of the wiper might be lowered. 
       FIG.  1    is a plan view schematically depicting the configuration of an ink-jet printer. 
       FIG.  2    is a bottom view depicting an example of a head of the ink-jet printer. 
       FIG.  3    is a cross-sectional view taken along a line in  FIG.  2   . 
       FIG.  4    is a block diagram schematically depicting the electric configuration in the ink-jet printer of the present embodiment. 
       FIG.  5    is a cross-sectional view taken along a line V-V in  FIG.  1   . 
       FIG.  6    is a cross-sectional view taken along a line IV-IV in  FIG.  1   . 
       FIG.  7    is a view schematically explaining a positional relationship between the head and a wiper at a time of a wiping operation. 
       FIG.  8 A  is a view schematically explaining the wiper as seen from a side of a first surface, and  FIG.  8 B  is a view schematically explaining the wiper as seen from a side of a second surface. 
       FIG.  9    is a view schematically explaining a positional relationship between a wiper body and the head. 
       FIG.  10 A  is a view schematically explaining a fixing member, and  FIG.  10 B  is a view schematically explaining a state that the wiper body is fixed to the fixing member. 
       FIG.  11 A  is a view schematically explaining a state that an upper end of the wiper body makes contact with the lower surface of the head, and  FIG.  11 B  is a view schematically explaining a state that a projection makes contact with the lower surface of the head. 
    
    
     In the following, an ink-jet printer  1  according to an embodiment of the present disclosure will be explained, with reference to the drawings. 
     In  FIG.  1   , the upstream side in a conveying direction of a medium M is defined as the front side of the ink-jet printer  1 , and the downstream side in the conveying direction is defined as the rear side of the ink-jet printer  1 . Further, a direction which is parallel to a plane or surface (conveyance plane or surface) in which the medium M such as print paper (print sheet, print paper sheet) is conveyed (a plane or surface parallel to the sheet surface of  FIG.  1   ) and which is orthogonal to the conveying direction is defined as a wiping direction. The wiping direction coincides with a width direction of the medium M. As will be described later on, the wiping direction is a direction in which the head  11  is moved with respect to a wiper  100  in a case that a wiping operation is performed by using the wiper  100 . One side of the wiping direction corresponds to the left side in a case that the ink-jet printer  1  is seen from the front side (the left side in  FIG.  1   ), and the other side of the wiping direction corresponds to the right side in a case that the ink-jet printer  1  is seen from the front side (the right side in  FIG.  1   ). Further, a direction orthogonal to the conveyance plane of the medium M (a direction orthogonal to the sheet surface of  FIG.  1   ) is defined as the up-down direction of the ink-jet printer. In  FIG.  1   , a side to which the front surface of the sheet is oriented or faces is the upper side, and a side to which the rear surface of the sheet is oriented or faces is the lower side. In the following explanation, the front (front side), the rear (rear side), the left (left side), the right (right side), the up (upper side) and the down (lower side) are appropriately used. 
     As depicted in  FIG.  1   , the ink-jet printer  1  is provided with a casing  2 , a platen  3 , a head bar  4 , conveying rollers  5 A and  5 B, a head holder  6 , a maintenance system  8  and a controller  10 . Note that the ink-jet printer  1  is an example of a “liquid discharge apparatus”. The configuration in which the head bar  4  and the maintenance system  8  are combined is an example of a “head bar system”. 
     As depicted in  FIG.  1   , the head holder  6  is arranged in the casing  2  so that the head holder  6  is movable in the wiping direction. The head holder  6  is arranged to sandwich, in the wiping direction, the both sides of the platen  3 . The head bar  4  is fixed to the head holder  6 . The head bar  4  is arranged at a location above the platen  3  so that a predetermined spacing distance is formed (defined) between the head bar  4  and the platen  3 . The medium M which is, for example, paper, etc., is conveyed on the upper surface of the platen  3 . 
     As depicted in  FIG.  1   , the head bar  4  is provided with 10 pieces of an ink-jet head  11  (hereinafter simply referred to as the “head(s)  11 ”. The ten heads  11  are arranged to form two rows along the wiping direction. Further, five heads  11 , among the ten heads  11 , which construct each of the two rows are arranged with equal spacing distances therebetween in the wiping direction. The two rows of the heads  11  are arranged to be shifted from each other in the wiping direction. Namely, the five heads  11  arranged on the upstream side in the conveying direction (the front side) are arranged to be shifted toward one side in the wiping direction (leftward) with respect to the five heads  11  arranged on the downstream side in the conveying direction (the rear side). In other words, the ten heads  11  are arranged in the staggered manner in the wiping direction. In the present embodiment, an ink supplied from a non-illustrated ink supplying part is discharged or ejected from each of the heads  11 . 
     The conveying roller  5 A is arranged on the front side with respect to the platen  3 , and the conveying roller  5 B is arranged on the rear side with respect to the platen  3 . Each of the conveying rollers  5 A and  5 B is driven by a non-illustrated motor, and conveys the medium M on the platen  3  rearward. Note that the medium M may be a roll-shaped sheet including a supply roll arranged on the upstream side in the conveying direction with respect to the platen  3 , and a recovery roll arranged on the downstream side in the conveying direction with respect to the platen  3 . In such a case, the medium M which is fed out from the supply roll passes on the platen  3 , and then is wound around (is taken up by) the recovery roll. Note that the supply roll may be attached to the conveying roller  5 A, and that the recovery roll may be attached to the conveying roller  5 B. Alternatively, the medium M may be a roll-shaped sheet including only a supply roll arranged on the upstream side in the conveying direction with respect to the platen  3 . In this case, the supply roller may be attached to the conveying roller  5 A. 
     The maintenance system  8  is arranged, in the inside of the casing  2 , at a location between the platen  3  and the head bar  4  regarding the up-down direction. As depicted in FIG. 1 , the maintenance system  8  is mainly provided with two wipers  100 , a maintenance base  82 , a pinion gear  83 , a rack gear  84 , a guide  85 , a driving motor  86  (see  FIG.  4   ) and an engaging block  87  (see  FIG.  6   ). In a case that maintenance is performed, the wiper  100  is caused to wipe a lower surface (a nozzle surface  41 A and a lower surface of a nozzle cover  241  (see  FIG.  2   ) which will be described later on) of each of the heads  11  while moving the head holder  6  (and the head bar  4 ) along the rack gear  84  toward the one side (right side) in the wiping direction. As depicted in  FIG.  1   , the rack gear  84  extends up to the right side with respect to (beyond) the maintenance base  82 . In a case that the maintenance is not performed, the head bar  4  is arranged at a position at which the head bar  4  does not interfere with the maintenance base  82  on the left side with respect to the maintenance base  82  (stand-by position, printing position). The detailed configuration of the maintenance system  8  will be described later on. 
     The controller  10  is capable of mutually communicating with an external apparatus  1000  such as a personal computer, etc. The controller  10  controls the operations of the respective heads  11  included in the head bar  4 , the conveying rollers  5 A and  5 B and the maintenance system  8 , based on an instruction from the external apparatus  1000  or an instruction from a user via an operating part (not depicted) provided on the ink-jet printer  1 . 
     Next, the lower surface of the head bar  4  and the lower surface of each of the heads  11  will be explained, with reference to  FIG.  2   . Note that  FIG.  2    depicts only a head  11  which is arranged rightmost among the five heads  11  arranged on the upstream side in the conveying direction and a head  11  which is arranged rightmost among the five heads  11  arranged on the downstream side in the conveying direction, and remaining heads  11  other than these two heads  11  are omitted in the illustration. 
     A bottom surface of each of the heads  11  faces or is opposite to the platen  3 . Further, a nozzle surface  41 A in which 1680 pieces of a nozzle  11   a  are opened is included in the bottom surface of each of the heads  11 . In the nozzle surface  41 A, the 1680 nozzles  11   a  form 24 pieces of a nozzle row arranged side by side in the conveying direction. Furthermore, each of the 24 nozzle rows includes 70 pieces of the nozzle  11   a  arranged side by side in the wiping direction with equal spacing distances therebetween. Each of the  70  nozzles  11   a  constructing one of the nozzle rows is arranged to be shifted in the wiping direction with respect to one of the 70 nozzles  11   a  constructing another nozzle row adjacent thereto in the conveying direction. In the following explanation, a virtual area which is an area which is on the inner side with respect to an outer edge of the nozzle surface  41 A of each of the heads  11  and which includes all the nozzles  11   a  formed in the nozzle surface  41 A in the inside of the area is referred to as a nozzle formation area  41 B. Further, each of the heads  11  has a nozzle cover  241  which is arranged therein and which is configured to cover the nozzle  41 A from therebelow so as to surround the nozzle formation area  41 B of the nozzle surface  41 A (see  FIGS.  2  and  9   ). As depicted in  FIG.  9   , the lower surface of the nozzle cover  241  protrude downward beyond the nozzle surface  41 A. In the following explanation, the lower surfaces of the nozzle surface  41 A and the nozzle cover  241  are collectively referred to as the “lower surface” of the head  11 , in some cases. 
     Ten pieces of an opening  4 A corresponding to the ten heads  11 , respectively, are formed in the lower surface of the head bar  4 . The ten openings  4 A are arranged in two rows in the staggered manner along the wiping direction. Five openings  4 A included in the ten openings  4 A and constructing each of the two rows are arranged in the wiping direction with equal spacing distances therebetween. As depicted in  FIG.  2   , each of the openings  4 A has a size which is substantially same as the lower surface of one of the heads  11 ; and the nozzle cover  241  and the nozzle surface  41 A (nozzle formation area  41 B) of each of the heads  11  is exposed from one of the openings  41 A corresponding thereto. Note that in the present embodiment, although not depicted in the drawings, the lower surface of the head bar  4  is flush with the nozzle surface  41 A of each of the heads  11 , and a lower end of the nozzle cover  241  of each of the heads  11  projects downward beyond the lower surface of the head bar  4 . Note that it is not necessarily indispensable that the lower surface of the head bar  4  is flush with the nozzle surface  41 A of each of the heads  11 . For example, it is allowable that the nozzle surface  41 A of each of the heads  11  protrudes downward beyond the lower surface of the head bar  4 . 
     Next, a channel unit  42  and an actuator unit  40  constructing each of the heads  11  will be explained, with reference to  FIGS.  2  to  4   . Note that since the configurations of the channel unit  42  and the actuator unit  40  are common to the ten heads  11 , the explanation will be given about the channel unit  42  and the actuator unit  40  in one piece of the head  11 . 
     As depicted in  FIG.  3   , the channel unit  42  is formed of a plurality of metal plates and a nozzle plate  41  which are stacked in the up-down direction. An ink channel such as individual channels  12  which include pressure chambers  12   a , respectively, a manifold  13 , etc., is formed in the plurality of metal plates by the etching. The nozzle plate  41  is formed, for example, of a polymeric synthetized resin material such as polyimide, etc., and is adhered to a lower surface of the stacked metal plates with an adhesive. A lower surface of the nozzle plate  41  becomes to be the above-described nozzle surface  41 A. Note that it is allowable that the nozzle plate  41  is also formed of a metallic material such as stainless steel, etc. 
     As depicted in  FIG.  3   , the individual channels  12  each of which communicates with one of the nozzles  11   a , and the manifold  13  communicating with the individual channels  12  are formed in the inside of the channel unit  42 . Although not depicted in the drawings, the manifold  13  extends in the wiping direction (in  FIG.  3   , a direction perpendicular to the sheet surface). The ink is supplied, via a non-illustrated ink supply port formed in the channel unit  42 , to the manifold  13  from a non-illustrated ink supplying part which is provided at the outside of the head  11 . 
     Note that although not depicted in the drawings, 1680 pieces of the individual channel  12  are arranged so as to form 24 individual channel rows extending in the wiping direction, in corresponds to that the 1680 nozzles  11   a  are arranged so as to form the 24 nozzle rows extending in the wiping direction, as described above. Further, 12 pieces of the manifold  13  are provided on the channel unit  24 ; each of the 12 manifolds  13  communicates with 140 individual channels  12 , among the 1680 individual channels  12 , constructing two individual channel rows among the 24 individual channel rows. With this, in the inside of the channel unit  42 , a plurality of ink channels are formed, each of the plurality of ink channel starting from the manifold  13 , passing the pressure chamber  12   a  of one of the plurality of individual channels  12 , and reaching one of the nozzles  11   a . Note that the number (quantity) of the manifold  13  formed in the channel unit  42  and the number (quantity) of the individual channel  12  communicating with the manifold  13  are not limited to or restricted by the above-described numbers (quantities). 
     As depicted in  FIG.  3   , one of the pressure chambers  12   a  is formed in each of the individual channels  12 , and the actuator unit  40  is arranged at a location above the pressure chambers  12   a . The actuator unit  40  is provided with a vibration plate  43  arranged on the upper surface of the channel unit  42  so as to cover all the pressure chambers  12   a , a piezoelectric body  44  arranged to cover the entire surface (entirety) of the upper surface of the vibration plate  43 , and 1680 individual electrodes  45  each of which is arranged, on the upper surface of the piezoelectric body  44 , at a position facing one of the pressure chambers  12   a . As will be described later on, the vibration plate  43  functions as a common electrode. The vibration plate  43  as the common electrode, each of the individual electrodes  45 , and a part, of the piezoelectric body  44 , which is sandwiched by one of the individual electrodes  45  and the vibration plate  43  form one piece of a driving element  46 . Namely, the actuator unit  40  includes 1680 pieces of the driving element  46 . 
     The vibration plate  43  is a metallic plate which has a substantially rectangular shape in a plan view, and is formed of an iron-based alloy such as stainless steel, a copper-based alloy, a nickel-based alloy, or a titanium-based alloy, etc. The upper surface of the vibration plate  43  having the electric conductivity is arranged on the side on which the lower surface of the piezoelectric body  44  is located. Accordingly, the upper surface of the vibration plate  43  is capable of functioning also as the common electrode. The vibration plate  43  as the common electrode is connected to a ground wiring of a driver IC  48  (see  FIG.  4   ) which drives the actuator unit  40 , and is maintained to be the ground potential at all times. Note that it is not necessarily indispensable that the vibration plate  43  is the metallic plate; for example, it is allowable that the vibration plate  43  is formed of a piezoelectric material which is same as that forming the piezoelectric body  44 , and that a metallic film as the common electrode is formed on the upper surface of the vibration plate  43 . 
     The piezoelectric body  44  is formed of a piezoelectric material composed primarily of lead zirconate titanate (PZT) which is a solid solution of lead titanate and lead zirconate and which is a ferroelectric substance. The piezoelectric body  44  is polarized in a thickness direction (up-down direction) at least at an area facing the pressure chamber  12   a  (a part sandwiched between the individual electrode  45  and the vibration plate  43 ). In the present embodiment, a layer of the piezoelectric body (piezoelectric layer) which is formed continuously across the plurality of pressure chambers  12   a  is formed on the upper surface of the vibration plate  43 . It is allowable, however, that 1680 pieces of an independent (separate) piezoelectric body  44  are provided, each corresponding to one of the 1680 pieces of the pressure chamber  12   a.    
     As depicted in  FIG.  3   , each of the individual electrodes  45  is arranged at an area, of the upper surface of the piezoelectric body  44 , which faces one of the pressure chambers  12   a . Each of the individual electrodes  45  is electrically connected to the driver IC  48  (see  FIG.  4   ) mounted on a non-illustrated flexible wiring (COF), via a signal line  34  (see  FIG.  4   ). As depicted in  FIG.  4   , the driver IC  48  is electrically connected to the controller  10 . The driver IC  48  applies a driving pulse signal to the individual electrode  45  of the driving element  46 , based on a signal transmitted from the controller  10 . With this, the driver IC  48  applies either one of a predetermined driving potential and the ground potential selectively to each of the individual electrodes  45 . 
     Next, an explanation will be given about an action of the driving element  46  of the actuator unit  40  at a time of ink discharge (ink ejection). In a case that the predetermined driving potential is applied from the driver IC  48  to a certain individual electrode  45  included in the individual electrodes  45 , a potential difference is generated between the certain individual electrode  45  to which the driving potential is applied and the vibration plate  43  as the common electrode and maintained at the ground potential. With this, an electric field in the thickness direction is generated at the part, of the piezoelectric body  44 , sandwiched between the certain individual electrode  45  and the vibration plate  43 . The direction of the electric filed is parallel to the polarization direction of the piezoelectric body  44 . Accordingly, due to this electric field, an area (active area), of the piezoelectric body  44 , which faces the certain individual electrode  45  contracts in a plane direction orthogonal to the thickness direction. Here, the vibration plate  43  which is on the lower side of the piezoelectric body  44  is fixed to the channel unit  42 . Accordingly, accompanying with the active area, of the piezoelectric body  44 , which is positioned on the upper surface of the vibration plate  43  contracting in the plane direction, a part of the vibration plate  43  which covers the pressure chamber  12   a  is deformed so as to project toward the pressure chamber  12   a  (unimorph deformation, see  FIG.  3   ). In this situation, since the volume inside the pressure chamber  12   a  is reduced, the pressure of the ink inside a certain pressure chamber  12   a , among the pressure chambers  12 , corresponding to the certain individual electrode  45  is increased, thereby discharging the ink from a nozzle  11   a , among the nozzles  11   a , communicating with the certain pressure chamber  12   a.    
     Next, an explanation will be given about the schematic electric configuration of the ink-jet printer  1 , with reference to  FIG.  4   . The controller  10  is electrically connected to each of the heads  11 . The controller  10  is mainly provided with a CPU (Central Processing Unit)  101 , a ROM (Read Only Memory)  102 , a RAM (Random Access Memory)  103 , and a non-volatile memory  104 . The ROM  102  stores a program(s), a variety of kinds of data, etc., with which the CPU controls a variety of kinds of operations. The RAM  103  is used as a memory area configured to temporarily store data, signal, etc., to be used by the CPU  101  for executing the program, or is used as a workspace for executing data processing. It is allowable to use, as the non-volatile memory  104 , for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory). Note that it is allowable to use a  1 VIPU (Microprocessor Unit) or a FPGA (Field Programmable Gate Array), rather than using the CPU  101 . 
     As depicted in  FIG.  4   , each of the heads  11  has a FPGA  20  and the driver IC  48 , in addition to the actuator unit  40  including the 1680 driving elements  46 . The FPGA  20  is connected to the drive IC  48  by a wiring  33  for control signal. Further, the driver IC  48  is connected to each of the driving elements  46  by a wiring  48  for driving signal. 
     In a case that the controller  10  receives image data from the external apparatus  1000 , the FPGA  20  outputs a control signal via the wiring  33  for control signal, under the control by the controller  10 . The driver IC  48  generates a driving signal for driving the actuator unit  40  based on the control signal inputted from the FPGA  20 , and outputs the generated driving signal to the actuator unit  40  via the wiring  34  for driving signal. 
     Further, a certain driving element  46 , among the driving elements  46 , is driven based on the driving signal supplied from the driver IC  48 , the ink is thereby discharged from a certain nozzle  11   a , among the nozzles  11   a , corresponding to the certain driving element  46 , in an amount corresponding to the driving signal. 
     Furthermore, the controller  10  is electrically connected to a conveying motor  51 , and controls the driving of the conveying motor  51  to thereby control the conveyance of the medium M by the conveying rollers  5 A and  5 B. Moreover, the controller  10  is electrically connected to the driving motor  86 , and controls the driving of the driving motor  86  to thereby control the movement of the head bar  4  in the wiping direction via the pinion gear  83 . 
     Next, the maintenance system  8  provided on the ink-jet printer  1  according to the present embodiment will be explained. 
     As depicted in  FIGS.  1 ,  5  and  7   , the rack gear  84  extends in the wiping direction. The rack gear  84  is arranged in the inside of the casing  2  (see  FIG.  1   ). As depicted in  FIG.  5   , teeth meshing or engaging with the pinion gear  83  are formed in the lower surface of the rack gear  84 . As depicted in  FIG.  7   , a length in the wiping direction of the rack gear  84  is longer than a length in the wiping direction of an area, of the head bar  4 , in which the ten heads  11  are arranged (hereinafter referred to as a “head arrangement area”). 
     As depicted in  FIG.  1   , the guide  85  extends in the wiping direction, and is arranged in the inside of the casing  2 . As depicted in  FIG.  6   , the guide  85  is arranged at a location below the rack gear  84  and the head holder  6 . Guide grooves  85 A are formed in side surfaces, respectively, which are on the both sides in the conveying direction of the guide  85 . A cross sectional shape of each of the guide grooves  85  is substantially rectangular, and each of the guide grooves  85 A extends in the wiping direction (direction perpendicular to the sheet surface of  FIG.  6   ). Note that as depicted in  FIG.  7   , a length in the wiping direction of the guide  85  is also longer than the length in the wiping direction of the head arrangement area in the head bar  4 . 
     The maintenance base  82  has a shape of a rectangular parallelepiped. As depicted in  FIG.  7   , a length in the conveying direction of the maintenance base  82  is longer than a length in the conveying direction of the head arrangement area in the head bar  4 . Further, as depicted in  FIG.  6   , a pinion gear  83  which protrudes rearward is provided on a side surface on one side in the conveying direction (rear side) of the head holder  6 , and the driving motor  86  connected to a rotation shaft  83 A of the pinion gear  83  is fixed to the inside of the maintenance base  82 . As depicted in  FIGS.  5  and  6   , the rotation shaft  83 A of the pinion gear  83  extends in the conveying direction, and teeth meshing with the teeth of the rack gear  84  are formed in a circumferential surface of the pinion gear  83 . Further, an engaging block  87  is provided on a location, in the lower surface of the head holder  6 , which is on the one side in the conveying direction (rear side). The engaging block  87  engages with the guide grooves  85 A of the guide  85 , while the pinion gear  83  meshes or engages with the rack gear  84 , thereby supporting the head holder  6 . Note that the positions in the up-down direction of the rack gear  84 , the guide  85  and the head holder  6  can be adjusted to a wiping position and to a retreating (retracting) position, by a non-illustrated lifting and lowering mechanism. The wiping position is a position at which an upper end  111  of the wiper  100  (to be described later on) is located above the nozzle surface  41 A (nozzle formation area  41 B) of the head  11 . The retreating position is a position at which the upper end  111  of the wiper  100  is located below the nozzle surface  41 A (nozzle formation area  41 B) of the head  11 . 
     As depicted in  FIG.  1   , the two wipers  100  are attached to the upper surface of the maintenance base  82 . Each of the two wipers  100  includes a member which is integrally formed by an EPDM rubber (a wiper body  110 , a base part  120  and a projection  130  which will be described later on). The EPDM rubber has the hardness of not less than 70 degrees, and has a property which is less likely to swell by the ink. The shape of each of the two wipers  100  will be described later on. As depicted in  FIGS.  1  and  7   , positions in the wiping direction of the two wipers  100  are shifted from each other. Specifically, a wiper  100  (hereinafter referred to as a “wiper  100 A”) included in the two wipers  100  and arranged on the upstream side in the conveying direction is arranged to shift to the one side in the wiping direction (to the left side, leftward) with respect to a wiper  100  (hereinafter referred to as a “wiper  100 B”) included in the two wipers  100  and arranged on the downstream side in the conveying direction. Further, as depicted in  FIG.  7   , the wiper  100 A is attached to the upper surface of the maintenance base  82  so that the nozzle formation area  41 B of each of the five heads  11  on the upstream side in the conveying direction (front side) is positioned between the both ends in the conveying direction of the wiper  100 A. Similarly, the wiper  100 B is attached to the upper surface of the maintenance base  82  so that the nozzle formation area  41 B of each of the five heads  11  on the downstream side in the conveying direction (rear side) is positioned between the both ends in the conveying direction of the wiper  100 B. 
     In a case that the pinion gear  83  rotates in normal and reverse directions in accordance with the driving of the driving motor  86 , the head holder  6  thereby moves in a reciprocal manner along the rack gear  84  and the guide  85  in the wiping direction. The head holder  6 , the driving motor  86 , the pinion gear  83 , the rack gear  84  and the guide  85  correspond to a “driving part” of the present disclosure. As will be described later on, in a state that the head holder  6  is moved to the maintenance position by the non-illustrated liftin-lowering mechanism, the head holder  6  is moved toward the right side in the wiping direction, thereby making it possible to perform a wiping operation of wiping the ink adhered to the nozzle formation area  41 B of the head  11 . In this situation, as depicted in  FIG.  7   , the upper end  111  (see  FIGS.  8 A and  8 B ) of the wiper  100 A successively makes contact with the nozzle formation areas  41 B of the respective five heads  11  on the upstream side in the conveying direction, and wipes off the ink adhered to the nozzle formation areas  41 B. Similarly, the upper end  111  (see  FIGS.  8 A and  8 B ) of the wiper  100 B successively makes contact with the nozzle formation areas  41 B of the respective five heads  11  on the downstream side in the conveying direction, and wipes off the ink adhered to the nozzle formation areas  41 B. Namely, each of the wiper  100 A and the wiper  100 B is capable of wiping a plurality of pieces of the nozzle formation area  41 B which are aligned in the wiping direction. In the maintenance system  8  of the present disclosure, since each of the wipers  100  is capable of wiping the plurality of pieces of the nozzle formation area in such a manner, it is possible to wipe the plurality of nozzle formation areas efficiently, and to shorten the time required for the maintenance. 
     Next, the shape of the wiper  100  will be explained, with reference to  FIGS.  8 A,  8 B,  9 ,  10 A and  10 B . As depicted in  FIGS.  8 A and  8 B , the wiper  100  is provided with a wiper body  110 , a base part  120 , two projections  131  and a fixing member  140  (see  FIGS.  7 ,  10 A and  10 B ). The wiper body  110  is a plate-like member elongated in the conveying direction. The wiper body  110  has a thickness in the wiping direction which becomes thinner further toward the upper side. A plurality of grooves  115  extending in the up-down direction are formed in a surface  113  (hereinafter referred to as a “first surface  113 ”) on the one side in the wiping direction (left side) of the wiper body  110 . A plurality of grooves  116  extending in the up-down direction and a plurality of grooves  117  extending in the conveying direction are formed in a surface  114  (hereinafter referred to as a “second surface  114 ”) on the other side in the wiping direction (right side) of the wiper body  110 . Stepped parts  112  of which height in the up-down direction is lower than the upper end  111  are formed, respectively, on both sides in the conveying direction of the upper end  111  of the wiper body  110 . The upper end  111  is an example of a “first area” of the present disclosure, and the stepped parts  112  are each an example of a “second area” of the present disclosure. In a case that the wiper  100  is at the wiping position, the upper end  111  makes contact with the nozzle surface  41  of the head  11 , and the stepped parts  112  make contact with the nozzle cover  241  of the head  11 , as will be described later on. 
     As depicted in  FIG.  8 A , the base part  120  is provided on a lower end of the first surface  113  of the wiper body  110 . The thickness (length in the wiping direction) of the base part  120  is greater than the thickness of the wiper body  110 . A projecting part  121  which projects in the up-down direction is formed at a central part in the conveying direction of the base part  120 . 
     As depicted in  FIG.  8 B , two projections  130  which project toward the other side (right side) in the wiping direction are formed in the second surface  114  of the wiper body  110 . In the present embodiment, the two projections  130  are arranged in the conveying direction with a spacing distance therebetween so that an inner side end in the conveying direction of each of the two projections  130  is located at a position which is same as one of the ends on the both sides in the conveying direction of the upper end  111  of the wiper body  110  (see  FIG.  9   ). In other words, each of the two projections  130  projects, in the second surface  114  of the wiper body  110 , from one of the stepped parts  112  toward the other side in the wiping direction (right side). Each of the projections  130  has a base  131  having a substantially rectangular parallelepiped shape and extending perpendicularly from the second surface  114 , and a supporting part  132  which spreads downward from a lower end of the base  131 . Note that an upper surface  131   a  of the base  131  is flush with one of the stepped parts  112  of the wiper body  110 . As will be described later on, in a case that the wiper  100  is at the wiping position, the upper surface  131   a  of the base  131  makes contact with the nozzle cover  241  of the head  11 . The upper surface  131   a  of the base  131  is an example of a “contact surface” of the present disclosure. 
     As depicted in  FIG.  8 B , a thickness in the conveying direction of the base  131  is greater than a thickness in the conveying direction of the supporting part  132 . An upper end of the supporting part  132  is continuously connected to a lower end of the base  131 , and a left end of the supporting part  132  is continuously connected to the second surfaced  114  of the wiper body  110 . A lower end of the supporting part  132  is located at a position lower than the center in the up-down direction of the second surface  114 . The supporting part  132  has a trapezoidal shape as seen in the conveying direction, and a length in the wiping direction of the supporting part  132  becomes longer further downward from the lower end of the base  131 . Further, a length in the up-down direction of the supporting part  132  becomes shorter as separating further away from the second surface  114  of the wiper body  110  toward the right side. 
     As depicted in  FIG.  9   , a width L 1  in the conveying direction of the upper end  111  of the wiper body  110  is greater than a length L 2  in the conveying direction of the nozzle formation area  41 B of each of the heads  11 , and is slightly smaller than an inner width L 3  of the nozzle cover  241 . Accordingly, in a case that the wiper  100  is positioned at the wiping position, the upper end  111  of the wiper body  100  is capable of making contact with the nozzle surface  41 B, without interfering with the nozzle cover  241 . Further, the width L 1  in the conveying direction of the upper end  111  of the wiper body  100  is greater than the length L 2  in the conveying direction of the nozzle formation area  41 B of each of the heads  11 . Accordingly, during the wiping operation, the upper end  111  of the wiper body  110  is capable of wiping the entirety of the nozzle formation area  41 B. Furthermore, a depth  1  in the up-down direction of the stepped parts  112  is substantially same as a height H in the up-down direction of the nozzle cover  241 . Moreover, as described above, the upper surface  131   a  of the base  131  is flush with the stepped parts  112  of the wiper body  110 . Accordingly, in the case that the wiper  100  is positioned at the wiping position, the stepped parts  112  of the wiper body  100  and the upper surface  131   a  of the base  131  are capable of making contact with the nozzle cover  241 . Further, a width L 4  in the conveying direction of the stepped parts  112  and a width L 5  in the conveying direction of the upper surface  131   a  of the base  131  are greater than a length L 6  in the conveying direction of the nozzle cover  241 . Accordingly, at the time of the wiping, the stepped parts  112  and the upper surface  131   a  of each of the projections  130  are capable of wiping the entirety of the nozzle cover  241 . 
     The fixing member  140  is a member configured to fix the wiper body  110  to the maintenance base  82 . As depicted in  FIG.  10 B , the fixing member  140  is provided with a first member  141  and a second member  145  which are fixable to the first member  141 . Note that the first member  141  is fixed to the maintenance base  82  (see  FIG.  7   ). As depicted in  FIG.  10 A , the first member  141  is a member having a cross section which is substantially a shape of a letter “L”, and elongated in the conveying direction. Two projecting bars  142  and  143  extending in the conveying direction are formed in a surface on the right side in the wiping direction of the first member  141 . The projecting bar  142  is positioned above the projecting bar  143 , and the projecting bars  142  and  143  are arranged with a spacing distance in the up-down direction. The projecting bar  142  is formed to have a discontinued gap  144  at a part in the conveying direction thereof. As depicted in  FIG.  10 B , it is possible to fix the wiper body  110  to the fixing member  140  by causing the base member  120  provided on the lower part of the wiper body  110  to be sandwiched between the first member  141  and the second member  145  in a state that the base part  120  is inserted between the two projecting bars  142  and  143 . Since the base part  120  is inserted between the two projecting bars  142  and  143 , there is no fear that the wiper body  110  might be deviated in the up-down direction. Further, although not depicted in the drawings, the projecting part  121  of the base part  120  engages with the gap  144  provided on the projecting bar  142 . With this, there is not such a fear that the wiper body  110  might be deviated in the conveying direction. 
     Next, the deformation of the wiper  100  during the wiping operation will be explained, with reference to  FIGS.  11 A and  11 B . 
     As depicted in  FIG.  11 A  in a dotted line, in a case that the wiper body  110  and the projection  130  do not make contact with the lower surface of the head  11 , the wiper body  110  stands vertically with respect to the maintenance base  82  so that the wiper body  110  is parallel to the up-down direction. A length L in the up-down direction (hereinafter referred to as a height L) of the wiper body  110  is greater than the distance in the up-down direction between the maintenance base  82  and the nozzle surface  41 A of the head  11 . In the case that the wiper body  110  do not make contact with the lower surface of the head  11 , the wiper body  110  and the head  11  overlap with each other in the up-down direction by an amount corresponding to a length LAP. Namely, the upper end  111  of the wiper body  110  is located above the nozzle surface  41 A of the head  11  by the length LAP. In this situation, a length of a part, which is included in the wiper body  110  and which does not overlap with the head  11  in the up-down direction, can be expressed as: length L-LAP. Note that the distance in the up-down direction between the upper end  111  of the wiper body  110  and the projection  130  is referred to as a distance 1. As described above, since the upper surface  131   a  of the projection  130  and the stepped parts  112  are flush with each other, the distance  1  corresponds to the depth in the up-down direction of the stepped parts  112  (see  FIG.  9   ). 
     As depicted in a solid line in  FIG.  11 A , in a case that the upper end  111  of the wiper body  110  makes contact with the nozzle surface  141 A, the wiper body  110  is deformed to be inclined by an angle θ 1  toward the other side in the wiping direction (right side), as compared with the case that the upper end  111  of the wiper body  110  does not make contact with the nozzle surface  141 A. Note that the angle θ 1  can be expressed as: θ 1 =arccos ((L-LAP)/L)[rad]. Note that since the projection  130  projects perpendicularly from the wiper body  110  toward the other side in the wiping direction (right side), the projection  130  does not make contact with the lower surface of the head  11  in a case that the upper end  111  of the wiper body  110  makes (is making) contact with the nozzle surface  41 A. In other words, in a case that the wiper body  110  makes (is making) contact with the nozzle surface  31 A of the head  11  and is thereby (being) deformed, the projection  130  does not hinder the wiper body  110  from being deformed. 
     Here, such a case is presumed that the projection  130  is not provided on the wiper  100 . In a case that the wiper  100  moves, with respect to the head  11 , toward the one side in the wiping direction (left side) and that the upper end  111  of the wiper body  110  is separated from the nozzle surface  41 A, the wiper body  110  is abruptly restored to a parallel state in which the wiper body  110  is parallel to the up-down direction. Namely, the wiper body  110  is consequently restored to be inclined by the angle θ 1  toward the one side in the wiping direction (left side). In this situation, there is such a fear that the ink which has been wiped from the nozzle surface  41   a  by the wiping operation and adhered to the first surface  113  of the wiper body  110  might be scattered in the surrounding due to the abrupt restoration of the wiper body  110 . 
     In view of this, the projection  130  is provided on the wiper  100  in the present embodiment. In this case, as depicted by the solid line in  FIG.  11 B , in the case that the wiper  100  moves, with respect to the head  11 , toward the one side in the wiping direction (left side) and that the upper end  111  of the wiper body  110  is separated from the nozzle surface  41 A, the projection  130  makes contact with the lower surface of the head  11  (for example, the lower surface of the nozzle cover  241 ) before the wiper body  110  becomes to be parallel to the up-down direction. With this, in an instant that the upper end  111  of the wiper body  110  is separated from the nozzle surface  41 A, the wiper body is restored toward the one side in the wiping direction (left side) only by an angle θ 2  (θ 2 &lt;θ 1 ), rather than by the angle θ 1 . Here, the angle θ 2  can be expressed as: θ 2 =arccos ((L- 1 )/L)[rad]. Further, provided that a distance along the projection  130  between the wiper body  110  and a contact point between the projection  130  and the head  11  in the case that the projection  130  makes contact with the lower surface of the head  11  is expressed as “X”, the X can be expressed as: X=L.sin θ 2 . The distance X corresponds to a height of the projection  130  from the wiper body  110  which is required in a case of determining the height L of the wiper body  110 , the overlap LAP in the up-down direction between the wiper body  110  and the nozzle surface  41 A of the head  11  and the distance  1  in the up-down direction between the upper end  111  of the wiper body  110  and the projection  130 . 
     In a case that the wiper  100  moves further toward the one side in the wiping direction (left side) with respect to the head  11  and that the projection  130  is separated from the lower surface of the head  11 , the wiper body  110  is restored toward the one side in the wiping direction (left side) further only by an angle θ 3  (θ 3 =θ 1 −θ 2 ). With this, the wiper body  111  is restored to the state of being parallel to the up-down direction. In such a manner, the wiper body  110  is restored gradually in the two phases after the upper end  111  of the wiper body  110  is separated from the nozzle surface  41 A. With this, occurrence of such a situation that the ink which has been wiped from the nozzle surface  41   a  by the wiping operation and adhered to the first surface  113  of the wiper body  110  is scattered in the surrounding due to the abrupt restoration of the wiper body  110  is lowered. 
     Note that according to the calculation by the inventors, it is found out that in a case that the height L of the wiper body  110  is 10.5 mm, the overlap LAP in the up-down direction between the wiper body  110  and the nozzle surface  41 A of the head  11  is 1.5 mm, and the distance  1  in the up-down direction between the upper end  111  of the wiper body  110  and the projection  130  is 0.4 mm, the angle θ 1  is 31.0°, the angle θ 2  is 15.9° and the angle θ 3  is 15.1°; and that the required height X of the projection  130  from the wiper body  110  is 2.87 mm. Further, it is found out that in a case that the height L of the wiper body  110  is 10.5 mm, the overlap LAP in the up-down direction between the wiper body  110  and the nozzle surface  41 A of the head  11  is 1.0 mm, and the distance  1  in the up-down direction between the upper end  111  of the wiper body  110  and the projection  130  is 0.4 mm, the angle θ 1  is 25.2° , the angle θ 2  is 15.9° and the angle θ 3  is 9.3°; and that the required height X of the projection  130  from the wiper body  110  is 2.87 mm. Furthermore, it is found out that in a case that the height L of the wiper body  110  is 10.5 mm, the overlap LAP in the up-down direction between the wiper body  110  and the nozzle surface  41 A of the head  11  is 0.5 mm, and the distance  1  in the up-down direction between the upper end  111  of the wiper body  110  and the projection  130  is 0.4 mm, the angle θ 1  is 17.8°, the angle θ 2  is 15.9° and the angle θ 3  is 1.9°; and that the required height X of the projection  130  from the wiper body  110  is 2.87 mm. In such a manner, it is found out that by fixing the height X of the wiper body and by changing the value of the overlap LAP in the up-down direction between the wiper body  110  and the nozzle surface  41 A of the head  11 , the angles θ 1  and θ 2  change as described above. 
     &lt;Effect of Embodiment&gt; 
     In the above-described embodiment, the head  11  has the lower surface including the nozzle surface  41 A in which the nozzles  11   a  are opened. The wiper  100  is configured to make contact with the nozzle surface  41 A of the head  11  and to wipe the nozzle surface  41 A. The head holder  6 , the driving motor  86 , the inion gear  83 , the rack gear  84  and the guide  85  are collectively referred to as the driving part. By using the driving part, it is possible to move the head holder  6  (head  11 ) so that the wiper  100  moves toward the one side in the wiping direction (left side) relative to (with respect to) the head  11  in the state that the wiper  100  makes contact with the nozzle surface  41 A. Note that the present disclosure is not necessarily limited to a configuration wherein the head  11  moves in the wiping direction in the state that the wiper  100  is fixed. It is allowable that the wiper  100  is configured to move in the wiping direction in a state that the head  11  stands still, or that both of the head  11  and the wiper  100  are configured to move in the wiping direction. 
     The wiper  100  is provided with the wiper body  110  having the upper end  111  which is a wiping part configured to wipe the nozzle surface  41 A, and the projection  130  which projects from the wiper body  110  toward the other side in the wiping direction (right side). After the upper end  111  of the wiper body  110  is separated from the end part on the one side in the wiping direction (left side) of the nozzle surface  41 A, the projection  130  makes contact with the lower surface of the head  11  (the lower surface of the nozzle cover  241 ). 
     After the upper end  111  of the wiper body  100  is separated from the end part on the one side in the wiping direction (left side) of the nozzle surface  41 A, the projection  130  makes contact with the lower surface of the head  11  (the lower surface of the nozzle cover  241 ), which in turn suppress occurrence of such a situation that the deformation of the wiper body  110  is restored all at once. With this, the restoring speed of the wiper body  110  is suppressed to thereby suppress the occurrence of such a situation that the ink which has been wiped from the nozzle surface  41   a  by the wiping operation and adhered to the first surface  113  and the upper end  111  of the wiper body  110  is scattered in the surrounding due to the abrupt restoration of the wiper body  110 . By providing the projection  130  as described above on the wiper  100 , the restoring force of the wiper body  110  is suppressed. Accordingly, there is no need to provide a member which is different from the wiper  100  separately so as to suppress the restoring force of the wiper body  110 , and to suppress the manufacturing cost. Further, since the projection  130  is formed in the second surface  114  on the other side in the wiping direction (right side), the projection  130  does not affect the deformation of the wiper body  110  in a case that the wiper body  110  wipes the nozzle surface  41 A. Accordingly, even in a case that the projection  130  is formed so as to suppress the restoring force of the wiper body  110 , there is not such a fear that the wiping performance of the wiper  100  might be lowered. 
     In the above-described embodiment, the wiper body  110  and the projection  130  are produced by being integrally formed. With this, it is possible to suppress the increase in the manufacturing cost of the wiper  130 . 
     In the above-described embodiment, the projection  130  is provided with the upper surface  131   a  of the base  131  which extends perpendicularly from the second surface  114  on the other side in the wiping direction (right side) of the wiper body  110 , and makes contact with the lower surface of the nozzle cover  241  of the head  11 . With this, it is possible to wipe the lower surface of the nozzle cover  241  by using the upper surface  131   a  of the base  131  of the projection  130 . 
     In the above-described embodiment, the supporting part  132  is provided on the projection  130 , at the location below the base  131 . The upper end of the supporting part  132  is continuously connected to the lower end of the base  131 , and the left end of the supporting part  132  is continuously connected to the second surface  114  of the wiper body  110 . The supporting part  132  has a shape of trapezoid as seen in the conveying direction, and the length in the wiping direction of the supporting part  132  becomes longer further downward from the lower end of the base  131 . By adopting such a configuration, it is possible to support the base  131  of the projection  130  more stably by the supporting part  132 . 
     In the above-described embodiment, the wiper body  110  has the upper end  111  as the wiping part configured to wipe the nozzle surface  41 A and the first surface  113 . Accordingly, the ink wiped from the nozzle surface  41 A by the wiping operation adheres to the first surface  113  of the wiper body  110 . Since the plurality of grooves  115  extending in the up-down direction are formed in the first surface  113  of the wiper body  110 , it is possible to move the ink adhered to the first surface  113  downward via the plurality of grooves  115 . With this, it is possible to suppress the occurrence of such a situation that the ink adhered to the first surface  113  is scattered in the surrounding in a case that the deformation of the wiper body  110  is restored. 
     In the above-described embodiment, the two projections  130  which project from the second surface  114  of the wiper body  110  are provided on the wiper  100 . The two projections  130  are arranged with the spacing distance in the conveying direction orthogonal to the wiping direction. Since the two projections  130  are provided on the wiper  100  in such a manner, it is possible to wipe two locations at a time by using the two projections  130 . 
     Further, the two projections  130  make contact with the nozzle cover  241 , rather than making contact with the nozzle surface  41 A in the lower surface of the head  11 . With this, it is possible to wipe the nozzle cover  241  at the same time with the wiping of the nozzle surface  41 A, rather than wiping only the nozzle surface  41 A. 
     In the above-described embodiment, the wiper body  110  has the upper end  111  making contact with the nozzle surface  41 A at the time of the wiping, and the stepped parts  112  of which height in the up-down direction is lower than that of the upper end  111 . At the time of the wiping, the stepped parts  112  make contact with the nozzle cover  241  which covers the nozzle surface  41 A from therebelow. With this, it is possible to perform wiping for the nozzle surface  41 A and the nozzle cover  241  at a time during the wiping. 
     In the present embodiment, in a case that the wiper  100  moves toward the one side in the wiping direction (left side) relative to the head  11  and that the upper end  111  of the wiper body  110  is separated from the nozzle surface  41 A, the projections  130  make contact with the lower surface of the nozzle cover  241  before the wiper body  110  becomes to be parallel to the up-down direction. In this case, since the projections  130  do not collide against the nozzle surface  41 A, there is not a fear that the projections  130  might damage the nozzle surface  41 A. 
     In the present embodiment, the plurality of grooves  116  extending in the up-down direction and the plurality of grooves  117  extending in the conveying direction are formed in the second surface  114  of the wiper body  110 . The plurality of grooves  116  have the effect of moving the ink adhered to the second surface  114  downward, similarly to the plurality of grooves  115 . Further, by providing the plurality of grooves  117  on the second surface  114 , it is possible to make the wiper body  110  to be easily deformable. 
     In the present embodiment, the two projecting bars  142  and  143  which are configured to fit to the base part  120  of the wiper  100  are formed in the fixing member  140 . Further, the projecting bar  142  of the fixing part  142  is provided with the gap  144  configured to fit to the projecting part  121  of the base part  120  of the wiper  100 . Since the base part  120  is inserted between the two projecting bars  142  and  143 , there is no such a fear that that the wiper body  110  might be deviated in the up-down direction. Further, since the projecting part  121  of the base part  120  engages with the gap  144  formed in the projecting bar  142 , there is not such a fear that the wiper body  110  might be deviated in the conveying direction. 
     In the present embodiment, each of the first surface  113  and the second surface  114  of the wiper body  110  is a broad wide surface expanding in the conveying direction and the up-down direction. The thickness in the wiping direction of the wiper body  110  becomes thinner further upward. Further, the two projections  130  are arranged to be apart in the both sides in the conveying direction of the second surface  114 . Each of the projections  130  has the base  131  and the supporting part  132 . The lower end of the supporting part  132  is located below the center in the up-down direction of the second surface  114  of the wiper body  110 . Further, the length in the conveying direction of each of the projections  130  is greater than the thickness in the conveying direction of the wiper body  110 . 
     Also in such a case, since after the upper end  111  of the wiper body  110  is separated from the end part on the one side in the wiping direction (left side) of the nozzle surface  41 A, the projections  130  make contact with the lower surface of the head  11  (the lower surface of the nozzle cover  241 ), it is possible to suppress occurrence of such a situation that the deformation of the wiper body  110  is restored all at once. This suppresses the occurrence of such a situation that the ink which has been wiped from the nozzle surface  41 A by the wiping operation and adhered to the first surface  113  and the upper end  111  of the wiper body  110  is scattered in the surrounding due to the abrupt restoration of the wiper body  110 . Further, by providing the projections  130  as described above on the wiper  100 , the restoring force of the wiper body  110  is suppressed. Accordingly, there is no need to provide a member which is different from the wiper  100  separately so as to suppress the restoring force of the wiper body  110 , and thus it is possible to suppress the manufacturing cost. Further, since the projections  130  are formed in the second surface  114  on the other side in the wiping direction (right side), the projections  130  do not affect the deformation of the wiper body  110  in a case that the wiper body  110  wipes the nozzle surface  41 A. Accordingly, even in a case that the projections  130  are formed so as to suppress the restoring force of the wiper body  110 , there is no such a fear that the wiping performance of the wiper  100  might be lowered. 
     While the invention has been described in conjunction with various example structures outlined above and illustrated in the figures, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example embodiments of the disclosure, as set forth above, are intended to be illustrative of the invention, and not limiting the invention. Various changes may be made without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to embrace all known or later developed alternatives, modifications, variations, improvements, and/or substantial equivalents. Some specific examples of potential alternatives, modifications, or variations in the described invention are provided below. 
     In the above-described embodiment, the wiper body  110 , the base part  120  and the projections  130  of the wiper  100  are integrally formed of the EPDM rubber. The present embodiment, however, is not limited to or restricted by this. For example, it is allowable to form the wiper body  110 , the base part  120  and the projections  130  of a perfluoro fluorine rubber, rather than forming the wiper body  110 , the base part  120  and the projections  130  of the EPDM rubber. Further, it is not necessarily indispensable that the wiper body  110 , the base part  120  and the projections  130  are integrally formed; it is allowable to form the wiper body  110 , the base part  120  and the projections  130  by combining separate (individual) members. Furthermore, although the hardness of the wiper member  100  is preferably not less than 70 degrees, it is not necessarily indispensable that the hardness of the wiper body  110  is not less than 70 degrees. 
     In the above-described embodiment, although the two pieces of the projection  130  are provided, the present disclosure is not necessarily limited to such an aspect. For example, it is allowable that the number (quantity) of the projection  130  may be  1  (one), or not less than 3. Further, the position in the conveying direction of the projection  130  may also be changed as appropriate. 
     In the above-described embodiment, although the upper surface  131   a  of the base  131  of the projection  130  and the stepped part  112  are formed to be flush with each other with respect to the up-down direction, the present disclosure it not limited to such an aspect. For example, it is allowable that the projection  130  is arranged so that the upper surface  131   a  is located below the stepped part  112 . Further, in the above-described embodiment, the upper surface  131   a  of the base  131  and the stepped part  112  are configured to make contact with the nozzle cover  241  and to wipe the nozzle cover  241 . The present disclosure, however, is not limited to such an aspect. For example, it is not necessarily indispensable that the nozzle cover  241  is provided on the head  11 . In such a case, it is allowable that the stepped part  112  is not provided, and that the upper surface  131   a  of the base  131  is configured to make contact with the nozzle surface  41 A. 
     In the above-described embodiment, although the ink-jet printer  1  is provided with one piece of the head bar  4 , the number (quantity) of the head bar  4  may be plural. Note that the number of the head  11  provided on the head bar  4  is not limited to 10 (ten). Further, the number of the nozzle  11   a  opened in the nozzle surface  41 A, the number of the nozzle row, and the number of the nozzle  11   a  forming each of the nozzle rows are not limited to the numbers, respectively, as described above. Furthermore, it is also possible to change the number and the arrangement of the individual channel  12  and the driving element  46  as appropriate, in accordance with the number and the arrangement of the nozzle  11   a.    
     It is allowable that the position at which the wiper  110 A is attached is not shifted in the wiping direction with respect to the position at which the wiper  100 B is attached. Namely, in the maintenance base  82 , the attachment position of the wiper  100 A and the attachment position of the wiper  100 B may be aligned in the wiping direction. 
     In the above-described embodiment, although the wiper  100 A and the wiper  100 B are provided as the separate members, the present disclosure is not limited to this. For example, the wiper  100 A and the wiper  100 B may be formed or molded as one member by connecting an end part on the one side in the conveying direction (end of the rear side) of the wiper  100 A and an end part on the other side in the conveying direction (end part on the front side) of the wiper  100 B are connected by a connecting part. 
     In the above-described embodiment, the head holder  6  is supported by the rack gear  84  and the guide  85  which are arranged on the one side in the conveying direction (rear side) with respect to the head holder  6 , the present disclosure in not limited to this. For example, it is allowable to further provide a guide extending in the wiping direction on the other side in the conveying direction (front side) with respect to the head holder  6 , and to support an end part on the other side in the conveying direction of the head holder  6  with this guide. In this case, it is also allowable to provide, on the end part on the other side in the conveying direction on the lower surface of the head holder  6 , a roller which is slidable along the added guide. 
     Further, it is allowable to arrange an absorbing member, for example such as a sponge, etc., configured to absorb the ink adhered to the first surface  113  of the wiper body  110 , on the fixing member  140  of the wiper  100 . 
     In the above-described embodiment, the channel unit  42  of each of the heads  11  is provided with the actuator unit  40  having the 1680 driving elements  46  corresponding, respectively to the 1680 individual channels  12 . The present disclosure, however, is not limited to such an aspect. For example, it is allowable to provide, on the channel unit  42 , a heater configured to bump the ink inside each of the individual channels  12  so as to discharge the ink from the nozzle  11   a , instead of the actuator unit  40 . 
     The medium M is not limited to the paper such as the print paper; the medium M may be, for example, a film formed of a resin, cloth, etc.