Abstract:
The present invention provides a web processing device comprising: a coating unit which coats a long strip of web by using a bar having in an axial direction at least two spiral grooved portions differing in the spiraling direction of the spiral groove; and a cutting unit which cuts the coated web in the lengthwise direction in a coating position along the boundary between the two spiral grooved portions. By using the bar having two spiral grooved portions, any foreign matter can be quickly shoved out to prevent it from inviting a seam flaw and, moreover, the adverse effect of any seam flaw occurring along the boundary between the two spiral grooved portions can be eliminated, with the result that high-quality processed webs can be manufactured at a high yield.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a web processing device, and more particularly to a web processing device for manufacturing photosensitive films, such as photographic films, or magnetic tapes including computer backup tapes.  
         [0003]     2. Description of the Related Art  
         [0004]     Bar coaters are known as a device for applying a coating liquid to a continuously running long strip of web. A bar coater forms a coat layer over a surface of a continuously running web by discharging a coating liquid onto the part of the web upstream from the bar while keeping a columnar rod known as a bar in contact with the under face of the web. The bar is used in the same direction or the direction reverse to the continuous running of the web or in a stationary state. Known types of bars include a flat bar whose outer circumferential face is flat, a wire bar wound with a wire and a roll forming bar in whose outer circumferential face a spiral groove is cut.  
         [0005]     A bar coater using a roll forming bar, out of these different bars, is subject to a phenomenon in which any foreign matter such as burrs or chips from the web having reached the bar moves in the widthwise direction along the spiral groove, with the result that foreign matters positioned at the downstream end in the moving direction are shoved outward and automatically removed. At the same time, as foreign matters positioned at the upstream end in the moving direction move toward the middle part of the web, they may invite a seam flaw. In recent years, as the width of the web subjected to the coating process is greater than before, foreign matters on the web are more likely to fail to reach the edge of the web and thereby invite a seam flaw.  
         [0006]     Various shapes are proposed for roll forming bars conventionally. For instance, Japanese Utility Model Application Laid-Open No. 1994-29667 disclosed a bar having two spiral grooves which are symmetric between right and left. Since this bar moves foreign matters on the web rightward and leftward, they can be quickly shoved out of the edges of the web.  
       SUMMARY OF THE INVENTION  
       [0007]     However, it has been found that the use of a bar having two spiral grooves would give rise to seams and other flaws in the central position of the bar (namely on the boundary between the two spiral grooves), and this makes it impossible for the bar to be used as a satisfactory product. Thus, the present inventor tested a bar with two spiral grooves in various ways, and found that seam flaws both of thin coating and thick coating occurred on the boundary between the two spiral grooves, and that these seam flaws could hardly be eliminated even if the coating conditions were altered. Thus, even if seam flaws are controlled by using a bar having two spiral grooves, new seam flaws will occur, making it impossible for the bar to be used as a satisfactory product. Accordingly, it has been impossible to use a bar having two spiral grooves for practical purposes.  
         [0008]     An object of the present invention, attempted in view of these circumstances, is to provide a web processing device which can suppress seam flaws due to foreign matters by using a bar having two spiral grooves differing in spiraling direction and can eliminate the effects of seam flaws ensuing from the boundary between the two spiral grooves.  
         [0009]     In order to achieve the object stated above, according to a first aspect of the invention, a web processing device comprises a coating unit which coats a long strip of web by using a bar having in the axial direction at least two spiral grooved portions differing in the spiraling direction of the spiral groove, and a cutting unit which cuts the coated web in the lengthwise direction in a coating position along the boundary between the two spiral grooved portions.  
         [0010]     According to the first aspect of the invention, by combining a coating unit which performs coating by using a bar having at least two spiral grooved portions and a cutting unit which cuts a wider web into narrower strips, the cutting is accomplished along the boundary between the two grooved portions. As this causes the parts coated along the boundary between the grooved portions to be discarded as unnecessary ears of the cut web strips, they do not remain in the finished product and therefore have no adverse effect. Therefore according to the first aspect of the invention, by using the bar having two spiral grooved portions, any foreign matter can be quickly shoved out to prevent it from inviting a seam flaw and, moreover, the adverse effect of any seam flaw occurring along the boundary between the two spiral grooved portions can be eliminated, with the result that high-quality processed webs can be manufactured at a high yield.  
         [0011]     According to a second aspect of the invention, the coating unit according to the first aspect of the invention is provided with a coating position adjusting device which adjusts the coating position in the widthwise direction of the web by shifting in the bar or the web relative to the widthwise direction of the web. Therefore, according to the second aspect of the invention, it is possible to adjust the coating position along the boundary between the spiral grooved portions in the widthwise direction of the web.  
         [0012]     According to a third aspect of the invention, the cutting unit according to the first or second aspect of the invention is provided with a cutting position adjusting device which adjusts the cutting position in the widthwise direction of the web according to the coating position in the widthwise direction of the web in the coating unit. Therefore, according to the third aspect of the invention, it is possible to cut the web according to the coating position and securely along the boundary between the two spirally grooved portions.  
         [0013]     According to a fourth aspect of the invention, the boundary between the spiral grooved portions according to any of the first through third aspects of the invention is so formed as not to let the spiral grooves overlap each other. The use of a bar having such a shape allows no foreign matters to be caught on the boundary because there is no spiral groove, and therefore can prevent seam flaws due to foreign matters from occurring on the boundary.  
         [0014]     According to a fifth aspect of the invention, the boundary between the spiral grooved portions according to any of the first through third aspects of the invention is so formed as to overlap each other on the boundary between the grooved portions and the length of the overlapping part is kept not less than 10 mm but not more than 30 mm in the axial direction of the bar. The use of a bar having such a shape, as it causes the coating liquid to be held in both spiral grooves, seam flaws due to thin coating can be restrained along the boundary.  
         [0015]     According to a sixth aspect of the invention, the bar according to any of the first through third aspects of the invention is formed by joining together rods at the end face in which spiral grooves differing in spiraling direction are cut. The use of a bar having such a configuration causes any foreign matter to be shoved out instead of staying on the boundary between the grooved portions. Accordingly, seam flaws due to foreign matters can be prevented all over the web.  
         [0016]     The web processing device according to the present invention, as it performs coating by using a bar having at least two spiral grooved portions and a cutting unit which cuts the web in the coating position on the boundary between the grooved portions, the rate of seam flaw occurrence due to foreign matters can be restrained, and the adverse effect of any seam flaw occurring along the boundary can be eliminated, with the result that high-quality processed webs can be manufactured at a high yield. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a schematic showing the configuration of a web processing device according to the invention;  
         [0018]      FIG. 2  shows a front view of a bar in a coating unit;  
         [0019]      FIG. 3  shows area P in  FIG. 2  on an enlarged scale;  
         [0020]      FIG. 4  is a perspective view schematically showing the configuration of the coating unit and a cutting unit;  
         [0021]      FIG. 5  illustrates the action of the web processing device;  
         [0022]      FIG. 6  shows a bar whose boundary of spiral grooves which differs in configuration from that shown in  FIG. 3 ;  
         [0023]      FIG. 7  shows another bar whose boundary of spiral grooves which differs in configuration from that shown in  FIG. 3 ;  
         [0024]      FIG. 8  shows a front view of a bar in a second preferred embodiment of the invention; and  
         [0025]      FIG. 9  shows a front view of a bar which differs in configuration from that shown in  FIG. 8 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     Web processing devices, which are preferred embodiments of the present invention will be described below with reference to the accompanying drawings.  FIG. 1  is a schematic showing the configuration of a web processing device according to the invention.  
         [0027]     As shown in  FIG. 1 , a web processing device  10  is mainly configured of a coating unit  14 , a drying unit  16 , a cutting unit  18  and a winding unit  20 , wherein a long strip of web  12  runs to pass the coating unit  14 , the drying unit  16 , the cutting unit  18  and the winding unit  20  in that sequence. Therefore, the long strip of web  12  is first coated on its under face with a coating liquid by the coating unit  14 , then undergoes drying of the coating liquid by the drying unit  16  and, after being cut in the lengthwise direction by the cutting unit  18 , is wound into a roll by the winding unit  20 . The individual processing units will now be described below.  
         [0028]     The coating unit  14  comprises a supporting member  24  having a V-shaped groove  24 A at the top and a bar  22  supported by the groove  24 A of the supporting member  24 . The web  12  is wound around a guide roller and other elements not shown, and a running path is so formed that the web  12  be brought into contact with the bar  22  at a prescribed lap angle. A discharge path  26  for the coating liquid is formed upstream from the bar  22  in the running direction of this web  12 , and the coating liquid is discharged from this discharge path  26  toward the under face of the web  12 . The coating liquid having stuck to the under face of the web  12  is measured by the bar  22 , and a prescribed quantity of the coating liquid is applied to the under face of the web  12 .  
         [0029]      FIG. 2  shows a front view of the bar  22 . As shown in  FIG. 2 , in the bar  22 , spiral grooves X and Y differing in spiraling direction are formed separately on the right and left parts of the bar  22 . Thus a grooved portion  22 X, in which the spiral groove X is formed, is disposed in the right half of the bar  22 , and a grooved portion  22 Y in which the spiral groove Y, differing from the spiral groove X in spiraling direction, is formed is disposed in the left half of the bar  22 .  
         [0030]     The bar  22  of this kind can be fabricated by subjecting a columnar core bar, after being ground, to roll forming. Roll forming is accomplished by rotating, after removing convexes on the surface of the bar by grinding it with a die having no groove, either the core bar or a die having a groove in the circumferential direction and shifting the core bar in the axial direction, while pressing this die against the outer circumferential face of the core bar. The two different the spiral grooves X and Y differing in spiraling direction are formed by performing this roll forming in two separate rounds, one applied to the right end to the center of the core bar and the other to the left end to the center of the core bar, and forming grooves in mutually reverse direction in those two rounds of roll forming. In this way, the grooved portion  22 X having the spiral groove X and the grooved portion  22 Y having the spiral groove Y are formed in the bar  22 . As the material of the core bar, a metal whose surface hardness is sufficient for roll forming, such as SUS  304  or SUS  316 , is used. There is no particular restriction regarding the shapes of the spiral groove X and Y, but they may have shapes of alternately repeated concaves and convexes each having an arciform section as shown in  FIG. 3 . Alternatively, concaves having an arciform section may as well be solely repeated, or convexes having an arciform section may as well be solely repeated.  
         [0031]     It is preferable for the core bar roll-formed as described above to be plated after its surface is completely cleared of adhesions by electrolytic defatting. A preferable way of plating is the formation of a coat of a hard material (for instance hard chromium plating, amorphous chromium plating, or the formatting of a ceramic coat, a diamond coat or a hard resin coat). The plating should preferably followed by buffing to remove pits and other flaws.  
         [0032]      FIG. 3  shows area P in  FIG. 2  on an enlarged scale. As shown in  FIG. 3 , the spiral groove X on the right side and the spiral groove Y on the left side are so formed as not to overlap each other in the central part. Thus, a flat part having neither the spiral groove X nor Y is disposed along the boundary Z between the grooved portion  22 X and the grooved portion  22 Y.  
         [0033]      FIG. 4  is a perspective view schematically showing the configuration of the coating unit  14  and the cutting unit  18  which are characteristic elements of the present invention. As shown in  FIG. 4 , the right end of the bar  22  of the coating unit  14  is linked to a rotating motor  30 , and by driving this rotating motor  30 , the bar  22  is turned in the running direction of the web  12 . The rotating motor  30  is mounted on a slide plate  32 , and this slide plate  32  is supported by a base  34  to be slidable in the widthwise direction of the bar  22  (namely the widthwise direction of the web). Further, a feed screw  36  is screwed into the slide plate  32 , and this feed screw  36  is turned by a positioning motor  40  via gears  38  and  38 . Therefore, by driving the positioning motor  40  to turn the feed screw  36 , the slide plate  32  and the rotating motor  30  slide to enable the position of the bar  22  to be adjusted in the widthwise direction. To add, the positioning motor  40  is connected to a controller  42 , and its driving is controlled by this controller  42 . The controller  42  is provided with an inching lever  42 A, and the positioning motor  40  is driven by manipulating this inching lever  42 A right and left to adjust the position of the bar  22  in the widthwise direction.  
         [0034]     A position detecting sensor  44  for detecting the position of the bar  22  in the widthwise direction is disposed to the left of the bar  22 . The position detecting sensor  44  is connected to the controller  42 , which subjects the position of the bar  22  to feedback control on the basis of the detection value of this position detecting sensor  44 .  
         [0035]     An edge position detecting sensor  46  for detecting the edge position of the web  12  is disposed on the upstream side of the bar  22  relative to the running direction of the web  12 . On the basis of the detection value of this edge position detecting sensor  46 , the controller  42  adjusts the position of the bar  22  in the widthwise direction, and arranges the boundary Z between the grooved portions  22 X and  22 Y in the central position of the web  12  in the widthwise direction.  
         [0036]     On the other hand, the cutting unit  18  is provided with a rotary cutter consisting of an upper cutting edge  50  and a lower cutting edge  52 , both disk-shaped. The upper cutting edge  50  is rotatably supported, while the lower cutting edge  52  is linked to a rotating motor  56 . By driving this rotating motor  56 , the lower cutting edge  52  is turned in tune with the running web  12 . Thus, the lower cutting edge  52  is turned in the running direction of the web  12  at the same speed as the web  12 . The web  12  is so arranged as to pass between the upper cutting edge  50  and the lower cutting edge  52 , which cut the web  12  in the lengthwise direction. A slide plate  58  is fitted to the rotating motor  56 , and this slide plate  58  is supported by a base  60  to be slidable in the widthwise direction of the web  12 . A feed screw  62  is screwed into the slide plate  58 , and this feed screw  62  is connected to a positioning motor  66  via gears  64  and  64 . Therefore, by driving the positioning motor  66 , the feed screw  62  is turned to shift the slide plate  58  the rotating motor  56  in the widthwise direction. As the upper cutting edge  50  and the lower cutting edge  52  are thereby shifted in the widthwise direction of the web  12 , the cutting position of the web  12  can be adjusted in the widthwise direction of the web  12 .  
         [0037]     An edge position detecting sensor  68  for detecting the edge position of the web  12  is disposed on the upstream side of the upper cutting edge  50  and the lower cutting edge  52  relative to the running direction of the web  12 . By adjusting the positions of the upper cutting edge  50  and the lower cutting edge  52  in the widthwise direction on the basis of the position detected by this edge position detecting sensor  68 , the controller  42  so exercises control as to cut the web  12  in the central position in the widthwise direction. Thus, the control is so effected as to cut it in the coated part along the boundary Z between the grooved portions  22 X and  22 Y.  
         [0038]     The cut webs  12  and  12 , which are narrowed in width, are wound by winding shafts  70  and  70  of the winding unit  20 , and the narrower webs  12  and  12  wound by the winding shafts  70  and  70  are cleared of their ends in the widthwise direction (ears) by equipment for post-treatment (not shown) to be finished into commercially marketable products.  
         [0039]     The operations of the web processing device  10  configured as described above will now be described.  
         [0040]     Foreign matters such as burrs (for instance peculiar return scraps of the cut portion resulting from cutting with a knife cutter in a high temperature ambience) or chips may be found on the ends of the webs  12 . These foreign matters, when they reach the coating unit  14 , are scraped off by the bar  22 . The foreign matters are then moved, together with the coating liquid, in the widthwise direction by the spiral motions of the spiral grooves X and Y of the bar  22  as shown in  FIG. 5 . Thus in the right half of the bar  22 , they are moved rightward by the action of the spiral groove X while in the left half of the bar  22 , they are moved leftward by the action of the spiral groove Y. Therefore, since the foreign matters are promptly shoved out without entering the central portion of the bar  22 , any seam flaw that could be caused by foreign matters can be prevented.  
         [0041]     As described above, since the two spiral grooves X and Y differing in spiraling direction are formed in the bar  22  in this embodiment of the invention, foreign matters can be positively removed by the bar  22  and therefore any seam flaw that could be caused by foreign matters can be prevented.  
         [0042]     Incidentally, tests conducted by the present inventor have revealed that the use the bar  22  having the two spiral grooves X and Y as described above invites seam flaws due to thin coating could occur along the boundary Z between the spiral grooves X and Y. Therefore, for this embodiment of the invention, control is so exercised as to bring the center of the bar  22  (i.e. the boundary Z between the grooved portions  22 X and  22 Y) to the central position of the web  12  in the widthwise direction in the coating unit  14  and to have the web  12  cut in its central position in the widthwise direction by the cutting unit  18 . Namely, the coating position on the boundary Z and the position of cutting by the cutting unit  18  are made identical in the widthwise direction of the web  12 . Therefore, on the cut webs  12  narrowed in width, any seam flaw that would arise as described would be on edges in the widthwise direction. These edges are removed as unnecessary ears in post-treatment. Therefore, this embodiment, since it is free from seam flaws in the central parts of the narrowed webs  12 , which are the finished products, can provide commercially marketable precuts of high quality.  
         [0043]     Further in this embodiment of the invention, as the bar  22  is fabricated by roll forming, the surface shape (i.e. the spiral grooves X and Y) can be formed with high accuracy. Also, as the bar  22  is made of a plated core bar, the surface hardness is enhanced to protect the surface of the bar  22  from damages and thereby to extend the useful life of the bar  22 . Moreover, as the roll-formed surface of the bar  22  is plated, the surface is difficult to be hardly smeared, and any seam flaw that could be caused by the adhesion of foreign matters can be thereby prevented.  
         [0044]     To add, though the coating position is adjusted by shifting the bar  22  in the widthwise direction in the embodiment described above, it can as well be adjusted by shifting the web  12  in the widthwise direction. Similarly, though the cutting position is adjusted by shifting the upper cutting edge  50  and the lower cutting edge  52  in the widthwise direction in the embodiment, the cutting position may as well be adjusted by shifting the web  12  in the widthwise direction. The shifting of the web  12  could be accomplished by shifting or inclining the guide roller (path roller).  
         [0045]     Although the coating position and the cutting position are adjusted independent of each other in the embodiment described above, it is sufficient to align the boundary Z between the grooved portions  22 X and  22 Y with the cutting position, and therefore either the coating position or the cutting position may be fixed. If for instance the coating position is fixed, the coating position can be detected and the cutting position can be adjusted according to that coating position.  
         [0046]     Further, though the spiral grooves X and Y are prevented from overlapping each other along the boundary Z between the grooved portions  22 X and  22 Y in the embodiment described above, the configuration of the boundary Z is not restricted to this. For instance, a bar  80  shown in  FIG. 6  is so configured that the spiral grooves X and Y partially overlap each other in the central part of the bar  80 . In this case, the incomplete peak parts of the spiral grooves X and Y (namely the parts where the groove depth is shallower than is specified) are laid one over the other, and the length L of the overlapping parts is kept not less than 10 mm but not more than 30 mm. The use of a bar  80  formed in this way, since the two incomplete peak parts overlap each for a length of at least 10 mm along the boundary Z, the incomplete peak parts can hold the coating liquid to restrain the occurrence of seam flaws due to thin coating more effectively than where these parts are flat. The length of the incomplete peak parts not more than 30 mm serves to prevent foreign matters from being held there to invite seam occurrence.  
         [0047]     A bar  82  shown in  FIG. 7  is formed by joining a rod in which a spiral groove X is cut and another rod in which a spiral groove Y is cut are joined at their respective end faces. Such a bar  82  has no incomplete groove in the boundary Z between the grooved portions  22 X and  22 Y, and can prevent seam flaws due to thin coating from occurring. Although the bar  82  might give rise to a seam flaw (level gap) due to thick coating along the boundary Z between the grooved portions  22 X and  22 Y, the cutting along the boundary Z between the spiral grooves X and Y in this embodiment can remove any such seam flaw.  
         [0048]     Next, a second preferred embodiment of the invention will be described. In this second preferred embodiment, the wider web  12  is cut in two positions in the widthwise direction in the cutting unit  18  shown in  FIG. 1 .  
         [0049]     As shown in  FIG. 8 , a bar  90  in the second embodiment has a spiral groove X formed in an approximately ⅔ part to the right and a spiral groove Y an approximately ⅓ part to the left. Thus, a grooved portion  90 X in which the spiral groove X is formed is disposed in an approximately ⅔ part of the bar  90  to the right and a grooved portion  90 Y in which the spiral groove Y is disposed in an approximately ⅓ part of the bar  90  to the left. The cutting unit  18  (not shown) in the second embodiment cuts the web not only along the boundary Z between the grooved portions  90 X and  90 Y but also in substantially the middle position of the grooved portion  90 X.  
         [0050]     In the grooved portion  90 X in the second embodiment configured as above, any foreign matter moves rightward, while in the grooved portion  90 Y any foreign matter moves leftward. Therefore, foreign matters can be shoved out more quickly and securely than where the bar  90  has only the spiral groove X or only the spiral groove Y, and seam flaws due to foreign matters can be restrained more effectively. Furthermore, since the web is cut along the boundary Z between the grooved portions  90 X and  90 Y in the second embodiment, any seam flaw occurring on the boundary Z can be removed by the time the web is fabricated into a finished product. Therefore, high-quality processed webs free from seam flaws can be manufactured.  
         [0051]     Although the spiral groove X is disposed in an approximately ⅔ part of the bar  90  to the right and the grooved portion  90 Y in which the spiral groove Y is disposed in an approximately ⅓ part of the bar  90  to the left in the second embodiment described above, conversely the spiral groove X may as well be disposed in an approximately ⅓ part of the bar  90  to the right and the spiral groove Y may as well be disposed in an approximately ⅔ part of the bar  90  to the left.  
         [0052]     Further, though two grooved portions  90 X and  90 Y are provided in the axial direction of the bar  90  in the second embodiment described above, three grooved portions may be disposed as well. For instance, as shown in  FIG. 9 , a grooved portion  92 Y having a spiral groove Y may be formed in an approximately ⅓ part of the bar  92  to the right, a grooved portion  92 X having a spiral groove X in an approximately ⅓ part in the middle, and another grooved portion  92 Y having another spiral groove Y in the remaining approximately ⅓ part to the left. In this case too, by cutting the web along the two boundaries Z and Z between the grooved portion  92 X on one hand and the grooved portions  92 Y and  92 Y on the other, a product free from seam flaws can be fabricated. Incidentally in this case, each of the three grooves may have a pitch and a depth differing from the others.  
         [0053]     Further, though the wider web  12  is supposed to be cut in two positions in the widthwise direction in the second embodiment described above, it may as well be cut in three or more positions. In this case, too, by matching the cutting positions with the boundaries Z between the grooved portions, a product free from seam flaws can be fabricated.