Patent Publication Number: US-8973496-B2

Title: Screen printing machine

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a screen printing machine, and more particularly, to a screen printing machine which screen-prints applying material such as a cream solder or a conductive paste on a substrate such as a printed wiring board (PWB) or a printed circuit board (PCB) as a pretreatment for mounting an electronic component to the substrate. 
     2. Description of the Related Art 
     For example, as disclosed in Japanese Patent Application Laid-open No. 2008-105294 (hereinafter, “Patent Document 1”), a screen printing machine includes a screen mask in which a print pattern is formed, and a squeegee. The screen mask is mounted to a predetermined mask mounting area. In a printing process, the squeegee moves over the screen mask relative to the screen mask. Applying material supplied to the screen mask is rolled by the squeegee and applied to a substrate through a print pattern. The print pattern of a screen mask corresponds to each substrate. Therefore, when a substrate that is a production object is changed, a screen mask is also changed. Conventionally, as expressively described in Patent Document 1, a change of screen masks necessitates replacement of squeegees. 
     Conventionally, replacement work of a screen mask required attaching and detaching a squeegee even when changing the squeegee was not required. In other words, applying material is adhered to a squeegee immediately after use. Therefore, a state exists where the applying material adhered to the squeegee is more likely to drip down into a mask mounting area. On the other hand, a substrate conveying mechanism and a substrate supporting mechanism are facing the mask mounting area. When the applying material drips onto these mechanisms, there is a risk that a substrate may become dirty or operations of the mechanisms may be obstructed. Therefore, conventionally, processes involving replacing a screen mask inevitably require that the squeegee be removed in advance. As a result, preparation work is time-consuming. In addition, the versatility of squeegees cannot be fully utilized. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in consideration of the problems described above, and an object thereof is to provide a screen printing machine capable of reducing preparation work and utilizing the versatility of a squeegee. 
     In order to solve the problems described above, the present invention is a screen printing machine that prints applying material on a substrate, the screen printing machine including: a screen mask detachably mounted to a mask mounting area set in advance; a squeegee that is arranged above the screen mask mounted to the mask mounting area, and the squeegee reciprocates relative to the screen mask in a squeegee-movement direction set in advance; and a receptacle which is installed at a location so that the screen mask is allowed to be attached and detached and which catches applying material adhered to the squeegee. In this mode, attachment/detachment work of a screen mask can be executed while catching applying material which may drip from the squeegee into the receptacle when attaching or detaching the screen mask. Therefore, the applying material adhered to the squeegee does not involuntarily drip into the mask mounting area during attaching or detaching of the screen mask. In addition, the catching of applying material is executed at the location so that the screen mask is allowed to be attached and detached. Therefore, replacement work of a screen mask can be executed while catching the applying material on the squeegee into the receptacle. As a result, the screen mask can be replaced while leaving the squeegee is mounted. Accordingly, attachment/detachment work of a screen mask during replacement is dramatically simplified and preparation work becomes easier. In addition, the versatility of a squeegee can be effectively utilized. 
     As described above, according to the present invention, the screen mask can be replaced while leaving the squeegee is mounted. Accordingly, attachment/detachment work during replacement of the screen mask is dramatically simplified and preparation work becomes easier. In addition, the versatility of a squeegee can be effectively utilized. 
     Other features, objects, configurations, and operational advantages of the present invention will be readily appreciated from the following detailed description when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a screen printing machine according to a first embodiment of the present invention; 
         FIG. 2  is a schematic plan view of the screen printing machine in a state where a screen mask is installed; 
         FIG. 3  is a perspective view showing the screen printing machine from a different angle; 
         FIG. 4  is a side view showing a schematic configuration of the screen printing machine; 
         FIG. 5  is a schematic front view of the screen printing machine; 
         FIG. 6A  is a schematic side view showing a schematic configuration of an assembly of a traveling unit, a lifting unit, a supplying unit, and a print head during lowering of the print head of the screen printing machine; 
         FIG. 6B  is a schematic side view showing a schematic configuration of the assembly of the traveling unit, the lifting unit, the supplying unit, and the print head during lifting of the print head of the screen printing machine; 
         FIG. 7  is a perspective view showing a substantial part of the print head of the screen printing machine; 
         FIG. 8  is a motion diagram showing an operation example of the print head of the screen printing machine; 
         FIG. 9  is a partial schematic side view showing an enlargement of a substantial part of the screen printing machine; 
         FIG. 10A  is an exploded perspective view showing a configuration regarding a receptacle of the screen printing machine; 
         FIG. 10B  is an assembly perspective view showing a configuration regarding the receptacle of the screen printing machine; 
         FIG. 11  is a perspective view showing a configuration regarding a camera unit of the screen printing machine; 
         FIG. 12  is a perspective view showing an enlargement of a substantial part of the camera unit; 
         FIG. 13  is a perspective view showing an operation of a scraping unit provided in the camera unit; 
         FIG. 14  is a partial enlarged schematic side view showing a substantial part of a screen printing machine according to a second embodiment of the present invention; 
         FIG. 15  is a perspective view showing a substantial part of the screen printing machine according to the second embodiment; 
         FIG. 16  is a partial enlarged schematic side view showing a substantial part of a screen printing machine according to a third embodiment of the present invention; 
         FIG. 17  is a partial enlarged schematic side view showing an operation of the screen printing machine according to the third embodiment; and 
         FIG. 18  is a motion diagram showing an operation example of a print head of the screen printing machine according to the third embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, preferable modes for carrying out the present invention will be described with reference to the accompanying drawings. Moreover, in the respective embodiments described below, common members will be designated by same reference numerals and redundant descriptions will be omitted. 
     First Embodiment 
       FIG. 1  is a perspective view showing a schematic configuration of a screen printing machine  10  according to a first embodiment of the present invention.  FIG. 2  is a schematic plan view of the screen printing machine  10  in a state where a screen mask  1  is installed. A print substrate W or a processing object is conveyed in leftward and rightward directions of the screen printing machine  10 . In the following description, a direction in a conveying direction of the substrate W when conveyed as mentioned above will be assumed to be an X-axis direction and forward and backward directions of the screen printing machine  10  will be assumed to be a Y-axis direction. 
     Referring to  FIGS. 1 and 2 , the screen mask  1  has a frame  2  with four corners and a mask sheet  3  provided in tension on the frame  2 . A print area  3   a  is formed in an approximately central portion of the mask sheet  3 . The print area  3   a  is a rectangular area which fits the print substrate W that is a print object. A pattern which conforms to a corresponding print substrate W is formed in the print area  3   a . The pattern is formed of pores. Applying material such as a cream solder or a conductive paste is supplied to the print area  3   a . When the applying material is pressed into the print area  3   a , the applying material is transferred to the print substrate W via the pattern. Moreover, in the following description, an area on a front side of the print area  3   a  will be referred to as a front outside-of-print area  3   b , and an area on a rear side of the print area  3   a  will be referred to as a rear outside-of-print area  3   c.    
     The screen mask  1  is detachably mounted to the screen printing machine  10  by an operator. 
     The screen printing machine  10  has a base  11 . The base  11  is a structure that is rectangular in plan view. Legs  11   a  are provided at four corners of the base  11 . The base  11  also has lower beams  11   b  which couple front and rear legs  11   a  with each other, and upper beams  11   c  which couple the front and rear legs  11   a  with each other above the lower beams  11   b . The lower beams  11   b  and the upper beams  11   c  are respectively provided to the left and the right of the base  11 . Conveying paths which convey the print substrate W in the X-axis direction are respectively formed between the lower beams  11   b  and the upper beams  11   c.    
     A mask supporting mechanism  12  which supports the screen mask  1  is provided on the upper beams  11   c  of the base  11 . Along a longitudinal direction of each of the upper beams  11   c , the mask supporting mechanism  12  includes a mask receiving plate  12   a  extended on an inner side of the upper beam  11   c  and a clamp unit  12   b  provided in an upper part of the mask receiving plate  12   a  (the four corners of the base  11 ). 
     As shown in  FIGS. 3 to 5 , each of the mask receiving plates  12   a  face each other at an interval set in advance in the X-axis direction and extend horizontally in the Y-axis direction at a same height. The mask receiving plates  12   a  are, respectively, members for receiving a lower surface of the frame  2  of the screen mask  1 . A stopper (not shown) for positioning the frame  2  of the screen mask  1  is provided at a lower end of the mask receiving plate  12   a.    
     The clamp unit  12   b  of the mask supporting mechanism  12  has a stay  12   c  fixed to the upper beam  11   c  and an air cylinder  12   d  mounted to the stay  12   c . The stay  12   c  is arranged at the four corners of the base  11  (refer to  FIG. 1 ). Each stay  12   c  faces a corresponding mask receiving plate  12   a  from above or below across a predetermined gap. Therefore, a space for inserting or removing the screen mask  1  forward or backward is formed between the mask receiving plates  12   a  and the stays  12   c . Accordingly, by inserting the screen mask  1  from the front of the screen printing machine  10  and positioning the screen mask  1  by the stopper, the screen mask  1  is mounted to a mask mounting area (an area in which the screen mask  1  is installed in  FIG. 2 ) defined by the base  11 . The air cylinders  12   d  provided on the respective stays  12   c  are arranged with each of their rods facing downward. Besides being controlled by a control unit  100  (to be described later), the air cylinders  12   d  can be operated from an operating panel (not shown). Due to the control or operation described above, the air cylinders  12   d  are switched between a clamp state where the rods are extended and a clamp release state where the rods are contracted. The mask receiving plate  12   a  and the clamp unit  12   b  constitute the mask supporting mechanism  12 . Due to the mask supporting mechanism  12 , the screen mask  1  is detachably mounted to the mask mounting area. 
     Substrate conveying conveyors (not shown) are installed on both sides of the base  11  in the X-axis direction. One substrate conveying conveyor constitutes a carry-in conveyor which carries the print substrate W into the base  11 , and the other substrate conveying conveyor constitutes a carry-out conveyor which carries out the print substrate W from the base  11 . A print stage  20  is installed in the base  11 . The print stage  20  receives the substrate W from the carry-in conveyor, and lifts the substrate W onto a lower surface of the mask sheet  3  according to a procedure set in advance. In addition, after a printing process is completed, the print stage  20  lowers the substrate W from the lower surface of the mask sheet  3  and hands over the substrate W to the carry-out conveyor. 
     Referring to  FIG. 4 , the print stage  20  includes a quadruple axes unit  21  and a substrate supporting unit  22  arranged above the quadruple axes unit  21 . 
     The quadruple axes unit  21  hierarchically includes a plurality of table mechanisms with different directions of movement. By combining these table mechanisms, the quadruple axes unit  21  supports the print substrate W carried in by the carry-in conveyor so as to be displaceable in directions of the X axis, the Y axis, a Z axis, and an R axis (rotation around the Z axis) while keeping the print substrate W horizontal. Each table mechanism of the quadruple axes unit  21  includes motors. The motors of the respective table mechanisms are controlled by the control unit  100  (to be described later). Due to control by the control unit  100 , the quadruple axes unit  21  is configured so as to be capable of moving the print substrate W supported by the quadruple axes unit  21  to a position where a camera unit  26  arranged on a left hand-side in  FIG. 4  is able to capture an image of the print substrate W. 
     The substrate supporting unit  22  includes a plurality of support pins  23  which receives a lower surface of the print substrate W, and a clamp unit  24  which clamps the print substrate W supported by the support pins  23 . The support pins  23  are mounted so as to be ascendable and descendable relative to the quadruple axes unit  21 . The clamp unit  24  is provided with a fixed portion  24   a  which is fixed to the quadruple axes unit  21  and a movable portion  24   b  which is capable of moving in the Y-axis direction relative to the fixed portion  24   a . Conveyor belts which form a pair to carry in or carry out the print substrate W in the X-axis direction are respectively mounted to upper ends of the fixed portion  24   a  and the movable portion  24   b . A position of the movable portion  24   b  is adjusted in correspondence with a dimension of the print substrate W in the Y-axis direction. When the print substrate W is carried onto the conveyor belt of the clamp unit  24  from the carry-in conveyor, the respective support pins  23  of the substrate supporting unit  22  protrude and support the print substrate W from a lower side thereof (a rear surface thereof). Then, the print substrate W is clamped by the clamp unit  24  in the Y-axis direction. Accordingly, the print substrate W is to be fixed in a state where the print substrate W is positioned with respect to the substrate supporting unit  22 . In addition, due to the lifting/lowering function of the quadruple axes unit  21 , the print substrate W carried by the substrate supporting unit  22  is capable of ascending and descending between two positions: an overlay mount position to which the print substrate W is lifted between both mask receiving plates  12   a  of the mask supporting mechanism  12  and at which the print substrate W is overlay-mounted on the lower surface of the mask sheet  3  of the screen mask  1 ; and a carry-out/carry-in position to which the print substrate W is lowered from the overlay mount position and at which the print substrate W is supplied to the substrate carry-in conveyor or the substrate carry-out conveyor. 
     A mask camera (not shown) is provided on the print stage  20 . The mask camera is an example of an imaging unit. The mask camera captures images of a plurality of fiducial marks (not shown) on the lower surface of the screen mask  1  supported by the mask supporting mechanism (to be described later). An image captured by the mask camera is processed by the control unit  100  as information for identifying a position, a type, or the like of the screen mask  1 . The mask camera is provided on the print stage  20  so as to be movable in the X-axis direction. In addition, due to the quadruple axes unit  21  of the print stage  20  being movable in the Y-axis direction, the mask camera is capable of capturing images of a plurality of fiducial marks or the like separated from each other in both the X-direction and the Y-direction and recognizing the positions of the fiducial marks or the like. 
     Moreover, since further configurations, operational advantages, and the like of the print stage  20  are disclosed in detail in, for example, Japanese Patent Application No. 2009-27310 (Japanese Patent Application Laid-open No. 2010-179628) previously submitted by the present applicant, a further description will be omitted. 
     Next, referring to  FIGS. 1 ,  2 , and  11 , a beam  13  extending in the X-axis direction is provided in a rear end portion of the base  11 . The beam  13  is placed laterally on an upper part of a rear end of the upper beam  11   c  of the base  11 . A pair of rails  14  that is vertically aligned is fixed to a side portion of the beam  13 . A slider  26   a  (refer to  FIG. 4 ) of the camera unit  26  is coupled to the rails  14 . In addition, a ball screw mechanism  28  is provided on the beam  13 . The ball screw mechanism  28  includes a ball screw  28   a  which is arranged between the rails  14  and which extends in the X-axis direction, a motor  28   b  which drives the ball screw  28   a , and a nut  28   c  (refer to  FIG. 4 ) which screws onto the ball screw  28   a . The nut  28   c  is fixed to the camera unit  26 . Therefore, the camera unit  26  is able to reciprocate in the X-axis direction within a range set in advance. The camera unit  26  includes a substrate camera  27 . The substrate camera  27  is an imaging unit for capturing images of a plurality of fiducial marks or the like of the print substrate W. Moreover, due to the quadruple axes unit  21  of the print stage  20  being movable in the Y-axis direction, the substrate camera  27  is capable of capturing images of a plurality of fiducial marks or the like separated from each other in the X-direction and the Y-direction and recognizing the positions of the fiducial marks or the like. 
     Referring to  FIGS. 2 to 5 , a traveling unit  30  is arranged in front of the camera unit  26 . The traveling unit  30  includes a supplying unit  40  which supplies applying material, and a print head  60  which rolls the supplied applying material on the mask sheet  3  and which presses the applying material into a pattern. 
     To mount the traveling unit  30 , Y-axis frames  11   e  are respectively rising on the left and right upper beams  11   c  of the base  11 . The Y-axis frames  11   e  are structures that extend in the Y-axis direction. Rails  11   f  are respectively fixed parallel to each other in the Y-axis direction to the upper portions of the Y-axis frames  11   e . Sliders  31  of the traveling unit  30  are respectively mounted in pairs on each rail  11   f.    
     Each slider  31  of the traveling unit  30  is capable of moving forward and backward in a stroke range set in advance. Each slider  31  carries a body  32 . The body  32  is a structure that integrally includes pillar-bodies  35  respectively provided left and right, and a beam  36  which couples the pillar-bodies  35  with each other in the X-axis direction. The pillar-bodies  35  respectively integrally include a foot portion  35   a  which is fixed to a corresponding slider  31  and a leg portion  35   b  which rises from the foot portion  35   a.    
     A ball screw mechanism  37  is coupled to the pillar-body  35  on a downstream side in a substrate conveying direction. The ball screw mechanism  37  includes a ball screw  37   a  which is rotatably mounted in the Y-axis direction to the Y-axis frame  11   e  on the downstream side in the substrate conveying direction, a motor  37   b  which drives the ball screw  37   a , and a slider  37   c  which includes a nut that screws onto the ball screw  37   a . The motor  37   b  rotates the ball screw  37   a  bi-directionally. In addition, the slider  37   c  is fixed to the foot portion  35   a  described earlier. Furthermore, due to control by the control unit  100 , when the motor  37   b  is actuated, the slider  37   c  moves forward or backward depending on a direction of rotation of the motor  37   b . The movement force in the direction is transferred from the foot portion  35   a  of the pillar-body  35  to the body  32  via the leg portion  35   b  to enable the body  32  to reciprocate along the rail  11   f.    
     Next, a reinforcing plate  35   c  is provided between the respective leg portions  35   b  of the body  32 . The reinforcing plate  35   c  is fixed between a side portion of each pillar-body  35  and a lower surface of the beam  36  and reinforces the body  32 . A guide rail  38  which extends in the X-axis direction is fixed to a front surface of the reinforcing plate  35   c . The supplying unit  40  is supported by the guide rail  38  via the slider  39 . The supplying unit  40  is configured so as to be reciprocable in the X-axis direction due to a ball screw mechanism (not shown) mounted on the body  32 . 
     Next, referring to  FIGS. 3 to 5 , the supplying unit  40  includes a unit frame  41 , a discharge adapter  42  which is detachably mounted to the front of the unit frame  41 , a container  43  which is mounted to the discharge adapter  42 , and a drive unit  44  which drives the container  43 . 
     The unit frame  41  is mounted to the slider  39  of the guide rail  38 . Therefore, the supplying unit  40  is capable of reciprocating in the X-axis direction as a whole. 
     The discharge adapter  42  includes an annular piston arranged facing upward. A applying material flow channel is vertically formed inside the piston. A shutter  45  is formed at a downstream end of the flow channel. When the shutter  45  is opened, applying material flowed out from the container  43  is discharged downward. 
     The container  43  is a bottomed cylinder which conforms to the piston of the discharge adapter  42 . The container  43  is filled with applying material upon delivery. By inserting the piston of the discharge adapter  42  into an opening of the container  43 , the container  43  is coupled so as to be displaceable relative to the discharge adapter  42 . In addition, an O ring is provided on an outer circumference of the piston. The O ring secures liquid tightness between the container  43  and the piston of the discharge adapter  42  while allowing relative displacement of the container  43  and the piston of the discharge adapter  42 . Furthermore, due to the container  43  being coupled to the discharge adapter  42 , the applying material in the container  43  is supplied from the discharge adapter  42 . Assembly of the container  43  and the discharge adapter  42  is attachable and detachable to and from the unit frame  41  from a front side of the screen printing machine  10 . 
     The drive unit  44  includes a ball screw mechanism and a pressing member which is vertically driven by the ball screw mechanism, and uses the pressing member to press the container  43  downward and supply the applying material in the container  43  to the discharge adapter  42 . 
     Moreover, since further configurations, operational advantages, and the like of the supplying unit  40  are disclosed in detail in, for example, Japanese Patent Application No. 2009-27310 (Japanese Patent Application Laid-open No. 2010-179628) described earlier, a further description will be omitted. 
     Next, a print head  60  is mounted to the traveling unit  30  via the lifting unit  50 . The print head  60  is arranged on a rear side of the supplying unit  40 . Due to the traveling unit  30 , the print head  60  reciprocates in the Y-axis direction together with the body  32 . In the following description, a movement from front to rear will be assumed to be an advancing movement and a movement in an opposite direction will be assumed to be a retreating movement. In the present embodiment, a direction in which the traveling unit  30  reciprocates is an example of a squeegee-movement direction. 
     Referring to  FIGS. 6A ,  6 B, and  7 , the print head  60  has a main frame  61  which is made of aluminum or the like. The main frame  61  is guided in the Z-axis direction by a guide rail (not shown) provided on the body  32  of the traveling unit  30 . In addition, the lifting unit  50  includes a ball screw mechanism  51  which vertically lifts and lowers the print head  60  via the main frame  61 . The ball screw mechanism  51  includes a ball screw  51   a  which is supported in the Z-axis direction so as to be rotatable around the Z-axis, a motor unit  51   b  which drives the ball screw  51   a , and a nut  51   c  which screws onto the ball screw  51   a . The nut  51   c  is mounted to the main frame  61 . An input pulley  51   d  is fixed to a head of the ball screw  51   a . In addition, the motor unit  51   b  is coupled to the pulley  51   d  by a timing belt or the like (not shown) so as to be capable of transferring power to the pulley  51   d . Therefore, the print head  60  is vertically lifted or lowered by the lifting unit  50  via the main frame  61 . As a result, due to the lifting unit  50 , the print head  60  is displaceable between a descending position where a squeegee  91  is abutted on the mask sheet  3  of the screen mask  1  as shown in  FIG. 6A , and an ascending position where the print head  60  rises to above the screen mask  1  as shown in  FIG. 6B . 
     Next, the print head  60  will be described in detail. 
     A support plate  63  is coupled via a sliding post  62  under the main frame  61  of the print head  60  so as to be displaceable in the Z-axis direction. A pressure sensor  64  such as a load cell is arranged between the support plate  63  and the main frame  61 . 
     A pair of bearings  65  is provided at a lower portion (lower surface) of the support plate  63 . Each bearing  65  faces along the Y-axis direction. The bearings  65  rotatably support a first support shaft  66  that extends in the Y-axis direction. A sub-frame  67  is fixed to the first support shaft  66 . Accordingly, the sub-frame  67  is swingably supported around the Y-axis. 
     A unit assembly  70  and a drive mechanism  80  for driving the unit assembly  70  are mounted on the sub-frame  67 . 
     Referring to  FIG. 7 , the unit assembly  70  includes an assemble plate  71 , a pair of coupling protrusions  72  protruding in a midway portion of the assemble plate  71  in a longitudinal direction thereof, and a second support shaft  73  that is fixed to each coupling protrusion  72 . 
     The assemble plate  71  is a rectangular plate-like member that is elongated in the X-axis direction. The coupling protrusions  72  face each other in the X-axis direction across the sub-frame  67 . The second support shaft  73  is fixed to the coupling protrusions  72  and, at the same time, rotatably coupled to the sub-frame  67  via a bearing or the like. Therefore, the unit assembly  70  is swingably supported around the X-axis with respect to the sub-frame  67 . 
     The drive mechanism  80  includes a gear box  81  and a servo motor  82 . The gear box  81  is fixed to one end (a left side in  FIG. 7 ) of the sub-frame  67 . In addition, one end of the pair of coupling protrusions  72  is arranged at one end of the gear box  81 . One end of the second support shaft  73  penetrates the gear box  81  and is fixed to the coupling protrusions  72  at the one end of the gear box  81 . 
     A transmission gear (not shown) is fixed to a portion inserted into the gear box  81  among the second support shaft  73 . An idle gear (not shown) that is supported inside the gear box  81  meshes with the transmission gear. The servo motor  82  as a drive source is fixed to the other end (a right side in  FIG. 7 ) of the sub-frame  67 . The servo motor  82  faces a side surface portion and extends toward an opposite side to the gear box  81  or the other end (the right side in  FIG. 7 ) in the X-axis direction. An output gear of the servo motor  82  is inserted into the gear box  81  and meshes with the idle gear. Accordingly, when the servo motor  82  is actuated, a torque of the servo motor  82  is transmitted to the second support shaft  73  via the respective gears. As a result, the unit assembly  70  is rotationally driven around the second support shaft  73 . The servo motor  82 , the respective gears, the second support shaft  73 , and the like constitute the drive mechanism  80  of the unit assembly  70 . 
     A squeegee unit  90  is detachably assembled onto the unit assembly  70 . The squeegee unit  90  includes a squeegee  91  and a squeegee holder  92  that holds the squeegee  91 . 
     The squeegee  91  is a plate-like member that is elongated in the X-axis direction. In order to give the squeegee  91  moderate elasticity, a material of the squeegee  91  is suitably selected from polymeric material such as urethane rubber, polyacetal, polyethylene, and polyester (urethane rubber is adopted in the illustrated embodiment). One surface of the squeegee  91  forms a flat working surface  91   a  for scraping solder. In addition, another surface of the squeegee  91  acts as a mounting surface to be fixed to the squeegee holder  92 . 
     Similar to the squeegee  91 , the squeegee holder  92  is a member that is elongated in the X-axis direction. A pair of bolts  93  is mounted to the squeegee holder  92 . The bolts  93  are inserted through a guide groove  71   a  that is formed in the assemble plate  71  of the unit assembly  70  when the squeegee holder  92  is placed on top of the unit assembly  70 . A nut member  94  screws onto each bolt  93 . The nut member  94  fastens the unit assembly  70  between the nut member  94  and the squeegee holder  92 . Accordingly, the squeegee holder  92  is fixed to the unit assembly  70 . A lateral leakage-preventing plate  95  is rotatably mounted to both sides of the squeegee holder  92 . The lateral leakage-preventing plate  95  is configured so as to be torsionable relative to the squeegee holder  92  due to the force of a torsion spring (not shown). Therefore, the lateral leakage-preventing plate  95  is held by the squeegee holder  92  so that a center line of the lateral leakage-preventing plate  95  is positioned perpendicular to the working surface  91   a  of the squeegee  91 . 
     As described earlier, with the print head  60  configured in this manner, the main frame  61  is coupled to the traveling unit  30  via the lifting unit  50 . Therefore, the squeegee  91  of the print head  60  advances or retreats relative to the screen mask  1  to perform a printing process. Printing performed by an advancing movement of the print head  60  is referred to as “advancing printing” and the opposite is referred to as “retreating printing”. With “advancing printing”, a printing operation is executed by advancing the squeegee  91 , moving a paste reservoir SP that is retained in the front outside-of-print area  3   b  to the rear outside-of-print area  3   c  to roll applying material, and kneading the applying material into the print area  3   a . In addition, with “retreating printing”, a printing operation is executed by moving the print head  60  in a retreating direction from the rear outside-of-print area  3   c  to the front outside-of-print area  3   b  or, in other words, in the Y-axis direction from the rear side to the front side to move the paste reservoir SP retained in the rear outside-of-print area  3   c  to the front outside-of-print area  3   b.    
     The servo motor  82  of the drive mechanism  80  rotationally moves the unit assembly  70  by a predetermined amount in accordance with a direction of the squeegee during a printing operation to adjust an attack angle of the squeegee  91 . Accordingly, the squeegee  91  is maintained in a lean-forward posture toward the downstream-side in the direction of advancing movement during advancing printing, and toward the downstream-side in the direction of retreating movement during retreating printing. As a result, the squeegee  91  is adjusted to an acute attack angle set in advance. In the illustrated embodiment, the drive mechanism  80  constitutes an angle varying means for varying an attack angle of the squeegee. 
     The screen printing machine  10  includes the control unit  100  (refer to  FIG. 4 ) for controlling the respective units described above. The control unit  100  is provided with a microprocessor, a memory, and other electronic devices, and logically constitutes a program executing section which executes various programs including printing processes and a data processing section which processes data supplied to the programs. The control unit  100  repetitively performs printing processes by controlling the respective portions of a print apparatus according to a print program stored in advance. In addition, the control unit  100  controls various motors and actuators such as an air cylinder built into the print stage  20  to carry the print substrate W in and out, position the print substrate W relative to the screen mask  1 , and the like. In addition, the control unit  100  controls the supplying unit  40  so that applying material is supplied to the screen mask  1 . Furthermore, the control unit  100  controls operations of the squeegee  91 . The control unit  100  includes a displaying/operating unit. The displaying/operating unit is a unit which displays a progress status, an error message, and the like of the print program and which functions as an interface used by a worker for inputting information such as various data and instructions to the control unit  100 . Various sensors are connected to the screen printing machine  10  in order to ensure that operations of the various portions are controlled accurately. The respective sensors are connected to the control unit  100  via an interface (not shown). 
     Next, a printing operation will be described. In a printing operation, a preparation step is first executed. In the preparation step, a width of the carry-in conveyor in the Y-axis direction, a width between the fixed portion  24   a  and the movable portion  24   b  of the print stage  20  in the Y-axis direction, and a width of the carry-out conveyor in the Y-axis direction are adjusted in accordance with a width of the print substrate W. In addition, after a new screen mask  1  is set by an operator, the frame  2  of the screen mask  1  is fixed to and arranged on the base  11  by the clamp unit  12   b . Furthermore, the squeegee holder  92  to which is assembled a desired squeegee  91  is assembled to the unit assembly  70 . Moreover, applying material is supplied to a surface of the screen mask  1  from the supplying unit  40  and a applying material paste reservoir SP along the X-axis is formed on a surface of the mask sheet  3 . 
     A printing step is executed after the preparation step. In the printing step, the respective portions of the screen printing machine  10  are controlled according to a print program stored in the control unit in advance to execute advancing printing and retreating printing by alternately switching between the two. 
     After the printing process, the substrate supporting unit  22  of the print stage  20  lowers the print substrate W and once again positions the print substrate W between the carry-in conveyor and the carry-out conveyor. In addition, the print substrate W after printing is carried out from the screen printing machine  10  by operations the reverse to the backup operation and the substrate clamping operation described above. 
     With the operations described above as one cycle, the screen printing machine  10  repeats the printing operation described above for each of a preset number of print substrates W. 
     When all printing operations are completed or when the screen mask  1  must be replaced in order to print a print substrate W with a different item number, in the present first embodiment, a rubbing operation of the squeegee  91  is performed at a timing set in advance using functions of the traveling unit  30  and the lifting unit  50 . 
     A more detailed description will now be given with reference to  FIGS. 2 and 8 . For example, after retreating printing is completed, the squeegee  91  of the print head  60  rises upward as depicted by [OPERATION B] in  FIG. 8  from a completion position depicted by [OPERATION A] in  FIG. 8 , and further moves in the retreating direction to straddle the applying material paste reservoir SP. Next, as depicted by [OPERATION C] in  FIG. 8 , the squeegee  91  descends in the front outside-of-print area  3   b  that is further forward than the paste reservoir SP. The squeegee  91  then retreats in a state where the squeegee  91  has landed on the mask sheet  3  of the screen mask  1 . Due to this retreating operation, excess applying material adhered to the squeegee  91  is removed in the front outside-of-print area  3   b . Moreover, when necessary, a further rubbing operation may be executed by further lifting the squeegee  91  as depicted by [OPERATION D] in  FIG. 8  from a downstream end position of a retreating movement and rotating the squeegee  91  around the second support shaft  73  (refer to  FIG. 7 ) to vary an attack angle thereof, and subsequently lowering the squeegee  91  as depicted by [OPERATION E] in  FIG. 8  and advancing the squeegee  91 . Due to this scraping operation, excess applying material adhered to the squeegee  91  is scraped off in the front outside-of-print area  3   b  of the mask sheet  3 . As a result, there is no longer a risk of the applying material dripping from the squeegee  91 . In the first embodiment, a further measure is taken in order to more reliably prevent dripping of the applying material from the squeegee  91 . This measure will be described below. 
     First, referring to  FIGS. 9 and 10 , a mounting frame  110  is provided on the base  11 . A receptacle  120  is held by the mounting frame  110 . 
     Referring now to  FIGS. 10A and 10B , the mounting frame  110  includes a frame main body  111  which extends in the X-axis direction. The frame main body  111  is a sheet-metal member that is rectangular in plan view. A total length of the frame main body  111  is set longer by a predetermined length than the frame  2  of the screen mask  1 . A front portion of the frame main body  111  is rectangularly notched. The rectangular notched portion is set longer than the frame  2  of the screen mask  1 . The frame main body  111  is arranged at a position which is slightly behind the screen mask  1  mounted to the mask mounting area and which faces above the screen mask  1 . The receptacle  120  is detachably held on an upper surface of the frame main body  111 . Therefore, the screen mask  1  is insertable and removable to the front and rear regardless of the mounting frame  110  and the receptacle  120 . 
     A pair of arms  112  which respectively extend forward is integrally provided at both end portions of the frame main body  111 . The arms  112  extend from a rear end to a side portion of the screen mask  1  mounted to the mask mounting area. Each of the arms  112  is fixed to both end portions of the frame main body  111  by an approximately rectangular plate portion  114 . In addition, a wall portion  113  is rising from the frame main body  111 . The wall portion  113  and the plate portion  114  are structures which support the receptacle  120 . Furthermore, protrusions  115  which position the receptacle  120  are respectively provided at both end portions of the frame main body  111 . 
     The receptacle  120  is held at a position facing above the frame  2  of the screen mask  1  mounted to the mask mounting area in a state where the receptacle  120  is position by the wall portion  113  and the protrusions  115  of the plate portion  114 . In the illustrated example, the receptacle  120  is made of magnetic stainless steel, and magnets  116  are mounted at appropriate positions of the wall portion  113  and the plate portion  114 . Therefore, the receptacle  120  is locked at a home position by the magnetic force of the magnets  116 . 
     The receptacle  120  integrally includes a bottom plate  121  formed rectangular in plan view and wall portions  122  and  123  rising from outer peripheral edges of the bottom plate  121 . Sections of the wall portions  122  and  123  near a front end of the bottom plate  121  are set low in order to prevent the wall portions  122  and  123  from interfering with the squeegee  91  and the like. 
     In the first embodiment, after the rubbing operation shown in  FIG. 8  is executed at a required timing, the squeegee  91  is driven to change its posture that is inclined by 75 degrees relative to a horizontal direction. The squeegee  91  is then moved to a position facing an upper portion of the receptacle  120  as shown in  FIG. 9 . 
     Next, in the first embodiment, a scraping unit  140  is provided in order to clean the squeegee  91  in a more reliable manner. 
     Referring to  FIGS. 9 ,  11 , and  12 , in the first embodiment, the scraping unit  140  is annexed to the camera unit  26 . Specifically, the scraping unit  140  includes an air cylinder  141  mounted to a side portion of the substrate camera  27  of the camera unit  26 , a mounting member  143  that is driven in the Y-axis direction by a rod  142  of the air cylinder  141 , a scraping metal  144  that is detachably mounted to the mounting member  143 , and a stud screw  145  that detachably clamps the scraping metal  144  to the mounting member. The air cylinder  141  may be mounted to the stay  26   b  of the camera unit  26  and orients the rod  142  in the Y-axis direction, for example. The rod  142  may be a pair of upper and lower members, for example. Each rod  142  carries the mounting member  143  which has an approximately plate piece-like shape. The mounting member  143  is formed as a rectangular parallelepiped that extends vertically. 
     The scraping metal  144  is a sheet-metal member which integrally includes a joining portion  144   a  that joins a mounting surface (front surface) of the mounting member  143 , an arm portion  144   b  which extends in the Y-axis direction from one end in a width direction (X-axis direction) of the joining portion  144   a , a wire portion  144   c  formed on tips of the arm portion  144   b  (an opposite side to the joining portion  144   a ) by providing an opening in the arm portion  144   b , and a reinforced portion  144   d  that is provided so as to extend from an upper end edge of the arm portion  144   b.    
     A pair of slits that open from one end toward the other end is formed in the joining portion  144   a . The slits correspond to a pair of upper and lower screw holes formed in the mounting member  143 . A screw portion of the stud screw  145  screws into the screw hole. The stud screw  145  includes a knob  145   a  diameter of which is larger than that of the screw portion, and by grasping the knob  145   a , a worker can screw the screw portion into or screw off the screw portion from the screw hole of the mounting member  143  without using any tools. In assemble state, the joining portion  144   a  is clamped to the mounting member  143  by the stud screw  145 . Therefore, the joining portion  144   a  is detachably held relative to the mounting member  143 . Moreover, in the illustrated embodiment, a groove that enables manipulation by a tool is formed in a head of the knob  145   a.    
     The arm portion  144   b  is a plate member that has an overall trapezoidal shape, and the wire portion  144   c  on the tip (forward in the Y-axis direction) of the arm portion  144   b  is inclined by, for example, 75 degrees relative to a horizontal plane in correspondence with an angle of inclination of the squeegee  91 . The wire portion  144   c  has a linear shape that is narrower than the opening formed in the arm portion  144   b . During actuation, the wire portion  144   c  contacts an entire width of the working surface  91   a  of the squeegee  91  and reciprocates in the X-axis direction relative to the squeegee  91 . Due to this operation, the wire portion  144   c  forcibly scrapes off applying material remaining on the working surface  91   a  of the squeegee  91  into the receptacle  120  below. In doing so, since the wire portion  144   c  has a narrow linear shape, the applying material scraped off by the wire portion  144   c  is more likely to drip downward along the wire portion  144   c . Therefore, the applying material is unlikely to adhere to the wire portion  144   c.    
     Due to control by the control unit  100 , the air cylinder  141  of the scraping unit  140  is capable of slightly moving back and forth (an oscillating movement) at a scraping position that faces above the receptacle  120 . Due to the oscillating movement, applying material adhered to the wire portion  144   c  is forcibly shaken off into the receptacle  120 . 
     With the configuration described above, the control unit  100  executes a rubbing operation of the squeegee  91  for each lot production, for example. With this rubbing operation, as already described with reference to  FIG. 8 , applying material adhered to the squeegee  91  is removed from in the front outside-of-print area  3   b  or the rear outside-of-print area  3   c  set on the mask sheet  3  of the screen mask  1 . Subsequently, the control unit  100  moves the print head  60  and causes the squeegee  91  to face above the receptacle  120 . The scraping metal  144  of the scraping unit  140  faces above the receptacle  120 . When necessary, the control unit  100  actuates the motor  28   b  of the ball screw mechanism  28  that drives the camera unit  26 . Accordingly, the wire portion  144   c  of the scraping metal  144  can slide in the X-axis direction relative to the squeegee  91  in a state where the wire portion  144   c  contacts the working surface  91   a  of the squeegee  91 . Due to this scraping operation, applying material remaining on the working surface  91   a  of the squeegee  91  is reliably scraped off. The scraped-off applying material is reliably collected inside the receptacle  120 . Therefore, there is no risk of the applying material scattering and soiling the inside of the screen printing machine  10 . 
     In another mode, after a printing operation is completed, the rubbing operation ( FIG. 8 ) may be omitted and the squeegee  91  may be immediately moved to above the receptacle  120  to execute a scraping operation. 
     An operator can execute replacement work of the screen mask  1  once the squeegee  91  moves to the receptacle  120 . In this case, since the replacement work of the screen mask  1  is executed in parallel to cleaning work of the squeegee  91 , preparation time can be reduced dramatically. Moreover, dripping of the applying material remaining on the squeegee  91  may be promoted by changing an attack angle of the squeegee  91  to the vicinity of 90 degrees (for example, to 75 degrees) during the movement of the squeegee  91  to above the receptacle  120 . 
     Second Embodiment 
     Next, a second embodiment will be described with reference to  FIGS. 14 and 15 . 
     As shown in the drawings, in the second embodiment, a scraping unit  140  is mounted to a supplying unit  40 . A stay  46  is annexed to a discharge adapter  42  of the supplying unit  40  according to the second embodiment, and an air cylinder  141  of the scraping unit  140  is mounted to the stay  46 . A rod  142  of the air cylinder  141  faces a squeegee  91  from front to rear. Since the supplying unit  40  and a print head  60  are mounted to a traveling unit  30 , the supplying unit  40  and the print head  60  integrally move in a Y-axis direction. Therefore, an interval across which the squeegee  91  and (a wire portion  144   c  of) scraping metal  144  of the scraping unit  140  face each other is set to an interval that does not obstruct a rotational movement of the squeegee  91 . At the same time, the rod  142  of the air cylinder  141  of the scraping unit  140  is set so as to be displaceable between a retreat position (a position shown in  FIG. 14 ) where the scraping metal  144  allows a rotational movement of the squeegee  91  and a sliding-contact position (a position shown in  FIG. 15 ) where the scraping metal  144  joins a working surface  91   a  of the squeegee  91 . 
     Otherwise, the second embodiment is similar to the first embodiment. 
     Even in the second embodiment, a cleaning operation of the squeegee  91  by the scraping unit  140  can be executed at a desired timing. 
     Third Embodiment 
     Next, a third embodiment will be described. 
     In the third embodiment, a double squeegee-type print head including two squeegees  91 A and  91 B is adopted as the print head  160 . 
     With the double squeegee-type print head  160 , an advancing unit  160 A that is used for advancing printing and a retreating unit  160 B that is used for retreating printing are mounted to a same main frame  161 . The respective units  160 A and  160 B include lifting units  162 A and  162 B and are configured so as to be capable of vertically lifting and lowering squeegee assembly portions  163 A and  163 B. The respective squeegee assembly units  163 A and  163 B carry the squeegees  91 A and  91 B at attack angles appropriate to respectively corresponding directions of movement. When executing advancing printing, the squeegee  91 A of the advancing unit  160 A is lowered while the squeegee  91 B of the retreating unit  160 B is lifted and the traveling unit advances. In addition, when executing retreating printing, the squeegee  91 A of the advancing unit  160 A is lifted while the squeegee  91 B of the retreating unit  160 B is lowered and the traveling unit retreats. 
     Depending on a printing operation, the control unit  100  selectively controls the advancing unit  160 A and the retreating unit  160 B. At the same time, during a required squeegee cleaning operation, the control unit  100  can lift or lower the squeegees  91 A and  91 B of both units  160 A and  160 B to supply the squeegees  91 A and  91 B to a scraping unit  240 . 
     The scraping unit  240  according to the third embodiment includes scraping metal  241  corresponding to the double squeegee-type print head  160 . The scraping metal  241  includes an advancing wire portion  241   a  that inclines in accordance with an angle of the advancing squeegee  91 A and a retreating wire portion  241   b  that inclines in accordance with an angle of the retreating squeegee  91 B. The advancing wire portion  241   a  and the retreating wire portion  241   b  are arranged so as to be left-right symmetrical and are set to specifications that allow the advancing wire portion  241   a  and the retreating wire portion  241   b  to simultaneously come into to sliding contact with the squeegee  91 A of the advancing unit  160 A and the squeegee  91 B of the retreating unit  160 B when both squeegees  91 A and  91 B are at a same height. 
     As a result, as shown in  FIG. 16 , by first adjusting the squeegee  91 A of the advancing unit  160 A and the squeegee  91 B of the retreating unit  160 B to a same height and having the squeegees  91 A and  91 B face above the scraping metal  241  and subsequently lowering the squeegees  91 A and  91 B of both units  160 A and  160 B, both squeegees  91 A and  91 B come into sliding contact with respectively corresponding wire portions  241   a  and  241   b  as shown in  FIG. 17 . By driving the scraping unit  240  in the X-axis direction in this state, the scraping metal  241  moves relative to both squeegees  91 A and  91 B. Consequently, applying material adhered to the working surfaces  91   a  of both squeegees  91 A and  91 B is forcibly scraped off by the wire portions  241   a  and  241   b  and collected in a receptacle  120 . 
     The scraping unit  240  may be mounted to a camera unit in a similar manner to the first embodiment or mounted to a supplying unit in a similar manner to the second embodiment. 
     As shown in  FIGS. 16 and 17 , the third embodiment is also provided with the receptacle  120 . Reflecting the fact that the print head  160  is a double squeegee-type print head, the receptacle  120  according to the third embodiment is set to specifications (in particular, dimensions in the Y-axis direction) that allow both the advancing unit  160 A and the retreating unit  160 B to simultaneously face the receptacle  120  from above. Accordingly, when the applying material adhered to the working surfaces  91   a  of both squeegees  91 A and  91 B is forcibly scraped off by the wire portions  241   a  and  241   b , the receptacle  120  can reliably collect the applying material. 
     In the third embodiment, a program of a control unit enables both squeegees  91 A and  91 B to execute a rubbing operation of the screen mask  1 . 
     A more detailed description will now be given with reference to  FIG. 18 . For example, when executing retreating printing, the squeegee  91 B of the retreating unit  160 B rises upward as depicted by [OPERATION B] in  FIG. 18  after the retreating printing is completed from a completion position depicted by [OPERATION A] in  FIG. 18 . Next, the print head  160  retreats as a whole and straddles a applying material paste reservoir SP. Subsequently, as depicted by [OPERATION C] in  FIG. 18 , the squeegee  91 B of the retreating unit  160 B descends in the front outside-of-print area  3   b  that is further forward than the paste reservoir SP. The squeegee  91 B of the retreating unit  160 B then retreats in a state where the squeegee  91 B is landed on the mask sheet  3  of the screen mask  1 . Due to this retreating operation, excess applying material adhered to the squeegee  91 B of the retreating unit  160 B is removed in the front outside-of-print area  3   b . Moreover, when necessary, a further rubbing operation may be executed by lifting the squeegee  91 B of the retreating unit  160 B from a downstream-end position of a retreating movement while lowering the squeegee  91 A of the advancing unit  160 A as depicted by [OPERATION D] in  FIG. 18  and then advancing the squeegee  91 A as depicted by [OPERATION E] in  FIG. 18 . Due to this rubbing operation, excess applying material adhered to the squeegee  91 A of the advancing unit  160 A is also removed in the front outside-of-print area  3   b  of the mask sheet  3 . As a result, there is no longer a risk of the applying material dripping from both squeegees  91 A and  91 B. 
     As described above, in the respective embodiments according to the present invention, attachment/detachment work of the screen mask  1  can be executed while catching applying material that may drip down from the squeegees  91 ,  91 A, and  91 B into the receptacle  120  when attaching or detaching the screen mask  1 . Therefore, the applying material adhered to the squeegees  91 ,  91 A, and  91 B does not involuntarily drip into the mask mounting area during attaching or detaching of the screen mask  1 . In addition, treatment of the applying material after catching can be performed more easily. Furthermore, the catching of applying material is executed at a location so that the screen mask is allowed to be attached and detached  1 . Therefore, replacement work of the screen mask  1  can be executed while catching the applying material on the squeegees  91 ,  91 A, and  91 B into the receptacle  120 . As a result, the screen mask  1  can be replaced while leaving the squeegees  91 ,  91 A, and  91 B mounted. Accordingly, attachment/detachment work during replacement of the screen mask  1  is dramatically simplified and preparation work becomes easier. In addition, the versatility of the squeegees  91 ,  91 A, and  91 B can be effectively utilized. 
     Furthermore, in the respective embodiments, the receptacle  120  is detachably fixed to a location so that the screen mask  1  is allowed to be attached and detached. Therefore, in the respective embodiments, since maintenance work can be performed by removing the receptacle  120 , maintainability can also be improved. 
     In addition, the respective embodiments further include a mounting frame  110  on which the receptacle  120  is mounted. The receptacle  120  is formed of a magnetic body, and the mounting frame  110  further includes a magnet  116  for locking the receptacle  120  to a catching area. Therefore, in the respective embodiments, the receptacle  120  can be detachably supported by the magnet  116 . Accordingly, handling of the receptacle  120  becomes easier. 
     In the respective embodiments, the screen mask  1  is so that a worker is allowed to insert and remove it at a front side (at one end) in the Y-axis direction, and the receptacle  120  is installed at a rear side (at the other end) in the Y-axis direction at a retreating position of the squeegees  91 ,  91 A, and  91 B. Therefore, in the respective embodiments, the worker can insert and remove the screen mask  1  on the front side in the Y-axis direction. During screen replacement, the squeegees  91 ,  91 A, and  91 B retreat to a side opposite to the worker or, in other words, to the rear side in the Y-axis direction. Therefore, the worker can perform work to insert and remove the screen mask  1  at a location that is furthest from the squeegees  91 ,  91 A, and  91 B. Accordingly, the worker can readily execute replacement work of the screen mask  1  without being distracted by the squeegees  91 ,  91 A, and  91 B. 
     Furthermore, the respective embodiments further include a lifting unit  50  that vertically drives the squeegees  91 ,  91 A, and  91 B, a traveling unit  30  which causes the squeegees  91 ,  91 A, and  91 B to reciprocate in respective Y-axis directions thereof via the lifting unit  50 , and a control unit  100  which controls the lifting unit  50  and the traveling unit  30  so that the squeegees  91 ,  91 A, and  91 B face above the receptacle  120  during replacement of the screen mask  1 . Therefore, in the respective embodiments, due to control by the control unit  100 , replacement work of the screen mask  1  can be executed while moving the squeegees  91 ,  91 A, and  91 B to above the receptacle  120  in order to avoid dripping of applying material. In particular, when the screen mask  1  is provided so that a worker can insert and remove the screen mask  1  on a front side (at one end) in the Y-axis direction and the receptacle  120  is provided at a position where the squeegees  91 ,  91 A, and  91 B retreat on a rear side (at the other end) in the Y-axis direction, the worker can execute replacement work of the screen mask  1  while completely ignoring the squeegees  91 ,  91 A, and  91 B. Therefore, workability can be improved. 
     In the respective embodiments, the control unit  100  controls the lifting unit  50  and the traveling unit  30  so that the squeegees  91 ,  91 A, and  91 B slide outside of a print area on the screen mask  1  after completion of a printing operation and allows the squeegee to move subsequently s  91 ,  91 A, and  91 B move to above the receptacle  120 . Therefore, in the respective embodiments, excess applying material can be scraped off outside of the print area in the screen mask  1  before moving the squeegees  91 ,  91 A, and  91 B to above the receptacle  120 . As a result, the applying material can be prevented from dripping during movement of the squeegees  91 ,  91 A, and  91 B. 
     Furthermore, in the first and second embodiments: the squeegee  91  is a single plate member of which attack angle is varied in accordance with the Y-axis direction; a gear box  81 , a servo motor  82 , a second support shaft  73 , and the like are further provided as angle varying means for varying the attack angle of the squeegee  91 ; and the control unit  100  controls a drive mechanism  80  as angle varying means so that the squeegee  91  inclines at a vertical angle or an angle in the vicinity of the vertical angle (for example, 75 degrees) during replacement of the screen mask  1 . Therefore, in the respective embodiments, when the squeegee  91  retreats to above the receptacle  120  during replacement of the screen mask  1 , applying material is more likely to drip from the squeegee  91  and catching is promoted. 
     In the third embodiment, the squeegees  91 A and  91 B are constituted by an advancing squeegee  91 A which slidingly contacts the screen mask  1  during an advancing movement, and a retreating squeegee  91 B which slidingly contacts the screen mask  1  during a retreating movement when reciprocating in the Y-axis direction, and the receptacle  120  is set to specifications which enable the receptacle  120  to face both the advancing squeegee  91 A and the retreating squeegee  91 B. Therefore, even when a so-called double squeegee-type print head is adopted, dripping of applying material from both squeegees  91 A and  91 B can be prevented. 
     In the respective embodiments described above, the receptacle  120  may be formed of a disposable material. Suitable disposable material includes paper and plastic. In this case, since caught applying material can be treated by replacing the receptacle  120 , handling of the receptacle  120  and the applying material becomes easier. 
     It is to be understood that the present invention is not limited to the embodiments described above and that various modifications may be made without departing from the spirit or scope of the present invention. 
     This application is based on Japanese Patent Application Serial No. 2012-162731, filed in Japan Patent Office on Jul. 23, 2012, the contents of which are hereby incorporated by reference.