Abstract:
In a method for manufacturing wet wipes, ridge regions raised along the conveyance direction are formed in sheets by causing each of the sheets to pass through between upper folding plates and a lower folding plate and folding the sheet multiple times on itself; each of the sheets having the ridge regions formed therein is impregnated with a predetermined chemical solution; and each of the sheets having been impregnated with the predetermined chemical solution is stacked on each other. After passing through between the upper folding plates and the lower folding plate, each of the sheets makes contact at a surface thereof with a conveyance roller, the surface being located opposite an extended plane across the surface having the ridge region formed therein, the extended plane being a plane obtained by extending the surface of the lower folding plate.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a method and an apparatus for manufacturing wet wipes. 
       BACKGROUND ART 
       [0002]    As a method for manufacturing wet wipes formed of a laminated body of sheets impregnated with a predetermined chemical, a method disclosed in Patent Literature 1 has been known. 
         [0003]    In the method disclosed in Patent Literature 1, a plurality of laminated original sheets (web) each folded back in a letter Z shape is conveyed as a laminated sheet which is configured so that: a rear face (a lower side, that is, a conveyance- device-contact surface side) comes in contact with a first conveyance roller arranged in the uppermost stream in a conveyance direction; a surface (an upper side, that is, a non-conveyance-device-contact face side) comes in contact with the second and third conveyance rollers arranged within an impregnation tank of the predetermined chemical; and the rear face (the lower side) comes in contact with the fourth conveyance roller arranged in the lowermost stream in the conveyance direction. 
         [0004]    Further, the wet wipes manufactured by the method disclosed in Patent Literature 1 have a configuration of a so-called pop-up type, in which at the time of removal of one sheet from a container, the next one sheet is also pulled out together and protruded from a slot of the container. 
       CITATION LIST 
     Patent Literature 
       [0005]    [Patent Literature 1] Japanese Patent No. 2777871 
       SUMMARY OF INVENTION 
       [0006]    However, according to the method disclosed in Patent Literature 1, there is no consideration for a contact surface between the laminated sheet and each conveyance roller, and the top face side and the rear face side of the laminated sheet have a different curvature radius at the time of passing through each conveyance roller. 
         [0007]    Therefore, the top face side of the laminated sheet is expanded by the first conveyance roller, and after being contracted by the second conveyance roller and the second conveyance roller, it is expanded again by the fourth conveyance roller. On the other hand, the rear face side of the laminated sheet is contracted by the first conveyance roller, and after being expanded by the second conveyance roller and the second conveyance roller, it is contracted again by the fourth roller. 
         [0008]    Note that the laminated sheet is formed of the plurality of laminated original sheets, so that in a single original sheet, similar expansion and contraction also occur in the top face side and the rear face when the laminated sheet passes through each conveyance roller. 
         [0009]    As a result, when the laminated sheet passes through each conveyance roller, in the original sheet, wrinkles occur in a part folded back in a letter Z shape, thereby causing a problem that conveyance of the laminated sheet becomes unstable. 
         [0010]    The present invention has been achieved in consideration of such circumstances, and an object thereof is to provide a method and an apparatus for manufacturing wet wipes, by which a sheet folded back at a non-conveyance-device-contact surface side can be conveyed stably. 
         [0011]    A first feature of the present invention is summarized as a method for manufacturing wet wipes formed of a laminated body of sheets impregnated with a predetermined chemical, the method comprising: a step of conveying sheets continuously by a conveyance device; a step of getting a respective one of the sheets through a space between au upper folding plate and a lower folding plate and folding back the respective one of the sheets multiple times to thereby form a raised region which rises while extending along a conveyance direction; a step of impregnating the respective one of the sheets having the raised region, with the predetermined chemical; and a step of laminating the respective sheets impregnated with the predetermined chemical, wherein after the respective one of the sheets passes through the space between the upper folding plate and the lower folding plate, an opposite surface side of a surface on which the raised region is formed, with respect to an extended surface of a surface of the lower folding plate, comes in contact with the conveyance device. 
         [0012]    A second feature of the present invention is summarized as manufacturing apparatus configured to manufacture wet wipes formed of a laminated body of sheets impregnated with a predetermined chemical, the apparatus comprising: a conveyance device configured to convey a plurality of sheets continuously; a folding unit configured to get a respective one of the sheets through a space between an upper folding plate and a lower folding plate and fold back the respective one of the sheets multiple times to form a raised region raised along a conveyance direction; an impregnating unit configured to impregnate the respective one of the sheets having the raised region, with the predetermined chemical; and a laminating unit configured to laminate the respective sheets impregnated with the predetermined chemical, wherein after the respective one of the sheets passes through the space between the upper folding plate and the lower folding plate, an opposite surface side of a surface on which the raised region is formed, with respect to an extended surface of a surface of the lower folding plate, comes in contact with the conveyance device. 
         [0013]    As described above, according to the present invention, it is possible to provide a method and an apparatus for manufacturing wet wipes, by which a sheet folded back at a non-conveyance-device-contact surface side can be conveyed stably. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a package body of wet wipes manufactured by a manufacturing apparatus according to a first embodiment of the present invention. 
           [0015]      FIG. 2  is a view for showing a state in which the wet wipes manufactured by the manufacturing apparatus according to the first embodiment of the present invention are contained inside the package body. 
           [0016]      FIG. 3  is a view for showing a state in which the wet wipes manufactured by the manufacturing apparatus according to the first embodiment of the present invention are contained inside the package body. 
           [0017]      FIG. 4  is a schematic view of the manufacturing apparatus according to the first embodiment of the present invention. 
           [0018]      FIG. 5  is a view for illustrating a folding unit of the manufacturing apparatus according to the first embodiment of the present invention. 
           [0019]      FIG. 6  is a view for illustrating an arrangement relationship among the folding unit, an impregnating unit, and a conveyance roller of the manufacturing apparatus according to the first embodiment of the present invention. 
           [0020]      FIG. 7  is a view for illustrating an arrangement relationship among the folding unit, the impregnating unit, and the conveyance roller of the manufacturing apparatus according to the first embodiment of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment of Present Invention 
       [0021]    With reference to  FIGS. 1 to 3 , wet wipes manufactured by a manufacturing apparatus  10  according to a first embodiment of the present invention are explained. Such wet wipes are formed of a laminated body of sheets  710 ,  720  impregnated with a predetermined chemical. 
         [0022]    As shown in  FIG. 1 , a package body  100  of such wet wipes has a package main body  20  having an opening unit  21 , a label member attached to the exterior face of the package main body  20  and cover the opening unit  21 , and the laminated body of the sheets  710 ,  720  contained inside the package main body  20 . 
         [0023]    Each of the sheets  710 ,  720  is contained inside the package main body  20  in a state where these sheets are folded back as shown in  FIGS. 2 and 3 . 
         [0024]    As shown in  FIGS. 2 and 3 , the sheet  720  has regions  31 A,  32 A,  33 A,  34 A,  35 A, whereas the sheet  710  has regions  31 B,  32 B,  33 B,  34 B,  35 B. 
         [0025]    Herein, in the sheet  720 , the regions  31 A,  32 A are folded back along a folding line  1 A. The regions  32 A,  33 A are folded back along a folding line  2 A. The regions  33 A,  34 A are folded back along a folding line  3 A. The regions  34 A,  35 A are folded back along a folding line  4 A. 
         [0026]    Similarly, in the sheet  710 , the regions  31 B,  32 B are folded back along a folding line  1 B. The regions  32 A,  33 A are folded back along a folding line  2 B. The regions  33 A,  34 A are folded back along a folding line  3 B. The regions  34 A,  35 A are folded back along a folding line  4 B. 
         [0027]    Note that in the sheet  720 , the folding lines  1 A,  2 A are provided between the folding lines  3 A,  4 A in the widthwise direction W, whereas in the sheet  710 , the folding lines  1 B,  2 B are provided between the folding lines  3 B,  4 B in the widthwise direction W. 
         [0028]    That is, in the sheet  720 , a region between the folding lines  1 A,  2 A in the widthwise direction W has a four-layered structure formed by folding back the regions  31 A,  32 A,  33 A,  34 A, whereas the other region has a two-layered structure formed by folding back the regions  33 A,  34 A. 
         [0029]    Therefore, the regions  31 A,  32 A rise in a lamination direction S of the laminated body while extending in one direction L of the laminated body. 
         [0030]    That is, the regions  31 A,  32 A are folded back along the folding lines  1 A,  2 A to thereby configure a raised region PA which is formed in the laminated body so as to rise in the lamination direction S while extending in the one direction L. 
         [0031]    Similarly, in the sheet  710 , a region between the folding lines  1 B, B in the widthwise direction W has a four-layered structure formed by folding back the regions  31 B,  32 B,  33 B,  34 B, whereas the other region has a two-layered structure formed by folding back the regions  33 B,  34 B. 
         [0032]    Therefore, the regions  31 B,  32 B rise in a lamination direction S of the laminated body while extending in the one direction L of the laminated body. 
         [0033]    That is, the regions  31 B,  32 B are folded back along the folding lines  1 B,  2 B to thereby configure a raised region PB which is formed in the laminated body so as to rise in the lamination direction S while extending in the longitudinal direction L. 
         [0034]    Further, a region (that is, a raised region PA) between the folding lines  1 B, B in the widthwise direction W is arranged so as not to be overlapped with a region (that is, a raised region PB) between the folding lines  1 B, B in the other direction. 
         [0035]    Further, in the raised regions PA, PB, the sheets  710 ,  720  which are adjacent to each other in the lamination direction S are laminated in close contact with each other with a predetermined chemical intervened therebetween. 
         [0036]    Herein, in regions RA, RB, RC adjacent to the raised regions PA, PB, a gap is formed between the sheets  710 ,  720  which are adjacent to each other in the lamination direction S, so that these sheets are not laminated in close contact with each other with the predetermined chemical intervened therebetween. 
         [0037]    Note that the wet wipes manufactured with the manufacturing apparatus  10  according to the first embodiment of the present invention are not configured as the aforementioned pop-up type. Therefore, even in a case where the sheet  720  is removed through the opening unit  21  of the package main body  20 , the sheet  710  is not pulled up together to be protruded from the opening unit  21 . 
         [0038]    That is, after removing the sheet  720  through the opening unit  21  of the package main body  20  by holding and pulling up the regions  31 A,  32 A (that is, the raised region PA of the sheet  720 ), a user can remove the sheet  710  by holding and pulling up the regions  31 B,  32 B (that is, the raised region PB of the sheet  70 ). 
         [0039]    Hereinafter, with reference to  FIG. 4 , a method for manufacturing wet wipes according to the present embodiment is simply explained. 
         [0040]    As shown in  FIG. 4 , in step S 101 , the folding unit  5  gets each of sheets  71 ,  72 , which was sent out from a wound state in a roller shape, through a space between upper folding plates  52  to  55  and a lower folding plate  51 , thereby folding back each of these sheets in a predetermined shape (specifically, a shape shown in  FIGS. 2 and 3 ) at the non-conveyance-device-contact surface side. 
         [0041]    That is, in step S 101 , the folding unit  5  gets each of the sheets  71 ,  72  through the space between the upper folding plates  52  to  55  and the lower folding plate  51  and folds back each of these sheets multiple times, thereby forming the raised regions PA, PB which rise while extending along a conveyance direction MD. 
         [0042]    For example, the sheets  71 ,  72  have a basis weight of 25 g/m 2  to 100 g/m 2 , and are formed of fibers made up of a hydrophilic fiber such as rayon, cotton, and pulp, and a simple substance such as PET, PP, PE, and acrylic, or a hydrophobic composite fiber with a sheath-core structure or a side-by-side structure. 
         [0043]    Further, the sheets  71 ,  72  are a nonwoven fabric which is shaped in a sheet-like form by a spun lace method, an air-laid method, a direct spinning method, or the like, and these sheets are required to include a hydrophilic fiber in terms of permeability of the predetermined chemical at the time of impregnation of the predetermined chemical. 
         [0044]    In step S 102 , an impregnating unit  1  impregnates each of the sheets  71 ,  72  with a predetermined amount of predetermined chemical from the conveyance-device-contact surface side (a conveyance roller  2  side), that is, the opposite surface side of the surface where the raised regions PA, PB are formed. 
         [0045]    In step S 103 , each of the sheets  71 ,  72  impregnated with the predetermined chemical is conveyed in contact with a surface of the conveyance roller  2 . 
         [0046]    Herein, after the sheets  71 ,  72  pass through the space between the upper folding plates  52  to  55  and the lower folding plate  51 , the opposite surface side of the surface on which the raised regions PA, PB are formed, with respect to an extended surface S of a surface of the lower folding plate  5 , comes in contact with the conveyance roller  2  (conveyance device) (see,  FIG. 7 ). 
         [0047]    In step S 104 , a pile roller  6  laminates each of the sheets  71 ,  72  impregnated with the predetermined chemical. 
         [0048]    Specifically, at the roller  6 , the sheet  72  is laminated on the sheet  71  from the non-conveyance-device-contact surface side, in a state where the surface of the sheet  72 , impregnated with the predetermined chemical, is faced to the conveyance-device-contact surface side (the pile roller  6  side) and the surface of the sheet  71 , impregnated with the predetermined chemical, is faced to the conveyance-device-contact surface side (the pile roller  6  side). 
         [0049]    At step S 105 , a cutting unit  4  cuts the sheets  71 ,  72  conveyed on a conveyance belt  3  into the sheets  710 ,  720  with a predetermined size. 
         [0050]    Thereafter, after the cut-out sheets  710 ,  720  are laminated by a predetermined number in a laminating step, these sheets are packaged in the package main body  20  in a packaging step. 
         [0051]    Hereinafter, with reference to  FIGS. 4 to 7 , each function of the manufacturing apparatus  10  according to the present embodiment is explained. 
         [0052]    As shown in  FIG. 4 , the manufacturing apparatus  10  has the folding unit  5 , the impregnating unit  1 , the conveyance roller  2 , the pile roller  6 , conveyors  3 ,  9 , and the cutting unit  4 . Herein, in the manufacturing apparatus  10 , the conveyance roller  2  and the conveyors  3 ,  9  configure the conveyance device which conveys the plurality of sheets  71 ,  72  continuously. 
         [0053]    As shown in  FIG. 5 , the folding unit  5  has the upper folding plates  52  to  55  and the lower folding plate  51 . Specifically, the folding unit  5  is configured to fold back each of the sheets  71 ,  72  at the non-conveyance-device-contact surface side by getting these sheets through the space between the upper folding plates  52  to  55  and the lower folding plate  51 . 
         [0054]    For example, the folding unit  5  is configured to fold back each of the sheets  71 ,  72  into a shape shown in  FIGS. 2 and 3 . 
         [0055]    That is, as shown in  FIGS. 6 and 7 , after the sheets  71 ,  72  pass through the space between the upper folding plates  52  to  55  and the lower folding plate  51 , the opposite surface side of the surface on which the raised regions PA, PB are formed, with respect to the extended surface S of the surface of the lower folding plate  51 , comes in contact with the conveyance roller  2  (conveyance device) (see,  FIG. 7 ). 
         [0056]    For example, the sheets  71 ,  72  having passed through the space between the upper folding plates  52  to  55  and the lower folding plate  51  are tilted toward the opposite surface side of the surface on which the raised regions PA, PB are formed, by degree a with respect to the extended surface S of the surface of the lower folding plate  51 , and these sheets  71 ,  72  are conveyed toward the conveyance roller  2 . 
         [0057]    The impregnating unit  1  is configured so as to impregnate each of the folded sheets  71 ,  72  with the predetermined chemical, from the conveyance-device-contact surface side. 
         [0058]    For example, the impregnating unit  1  may be configured so as to push out the predetermined chemical by a predetermined amount from a chemical tank by using a proportioning pump. As a result, a predetermined amount of the predetermined chemical is discharged from a pore provided in the impregnating unit  1  and comes in contact with the sheets  71 ,  72 , so that each of the sheets  71 ,  72  is impregnated with a predetermined amount of the predetermined chemical. 
         [0059]    Further, the impregnating unit  1  may be configured so as to impregnate the sheets  71 ,  72  with the predetermined chemical 3.5 (between 3 and 4) times heavier than the sheets  71 ,  72 . 
         [0060]    Note that a rate of a weight of the predetermined chemical, which is to be impregnated, to the sheets  71 ,  72  (that is, a rate of impregnation) is appropriately adjustable by the impregnating unit  1 . 
         [0061]    Herein, a rate of impregnation required for the sheets  71 ,  72  to adhere to the surface of the conveyance roller  2  and for the sheet  72  to adhere to the top of the sheet  71  is  1 . 5  times or more, for example, in a case of using as the sheets  71 ,  72 , a spun lace nonwoven fabric of 38 g/m 2  having a rayon fiber as a main constituent. 
         [0062]    Further, as a method of applying a predetermined chemical, the impregnating unit  1  may adopt a method for attaching a predetermined chemical in a droplet form or in a mist form to the sheets  71 ,  72 . However, the above-described method is preferable in consideration of a chemical impregnation rate and pollution by process at the time when the surfaces of the sheets  71 ,  72 , impregnated with the predetermined chemical, are brought in contact with the surface of the conveyance roller  2 . 
         [0063]    Further, the impregnating unit  1  may be configured so as to be installed upstream of the folding unit  5  in the conveyance direction MD and to impregnate the sheets  71 ,  72  with the predetermined chemical. 
         [0064]    However, it is preferable to use the above-described method in consideration of increase in a value of friction resistance at the time of getting the sheets  71 ,  72  through the folding unit  5 , tear of the sheets  71 ,  72 , decrease in a width of the sheets  71 ,  72 , pollution by process due to paper dust adhesion, and so on. 
         [0065]    The conveyance roller  2  is connected to a driving source and is a driving roller which rotates by itself and has a smooth surface. 
         [0066]    The pile roller  6  configures a laminating unit which laminates each of the sheets  71 ,  72  impregnated with the predetermined chemical. Further, the pile roller  6  is a roller having a smooth surface and configured to convey each of the sheets  71 ,  72  at an approximately equal conveyance speed to the conveyance roller  2 . 
         [0067]    The conveyor  3  is configured to convey each of the sheets  71 ,  72  at an approximately equal conveyance speed to the conveyance roller  2 . 
         [0068]    The cutting unit  4  is configured to cut the laminated body of the sheets  71 ,  72 . For example, the cutting unit  4  is configured by a cutter roller having a cutting blade on its surface and an anvil roller having a smooth surface. 
         [0069]    Further, likewise the conveyor  3 , a conveyor  9  may be configured by an upper conveyor and a lower conveyor. In such a case, the laminated body of the sheets  710 ,  720  is conveyed while it is sandwiched between the upper conveyor and the lower conveyor. 
         [0070]    As a result, it is possible to improve transferability to the conveyor  9  and conveyance stability of the laminated body of the sheets  710 ,  720  after being cut out by the cutting unit  4 . 
         [0071]    Further, such the upper conveyor may be provided with a concave unit and a convex unit. 
         [0072]    Herein, a conveyance speed of the conveyor  9  is 3% higher than the conveyor  3  and the cutting unit  4 . 
         [0073]    With the manufacturing method and the manufacturing apparatus  10  according to the present embodiment, the sheet  71 ,  72  can be conveyed stably without the raised regions PA, PB being flipped up or folded at the time when the sheets  71 ,  72  pass through the conveyance roller  2 . 
         [0074]    Further, with the manufacturing method and the manufacturing apparatus  10  according to the present embodiment, a means for positioning side portions of the sheets  71 ,  72  is arranged just before the folding unit  5 , so that the sheets  71 ,  72  can be folded back stably without getting side portions of the sheets  71 ,  72  out of position from the lower folding plate  51  of the folding unit t 5 . 
         [0075]    The sheets  71 ,  72  are conveyed while they are slightly expanded in a direction along the upper folding plates  52  to  55 , so that in the sheets  71 ,  72 , a length, in the conveyance direction MD, of the surface on which the raised regions PA, PB are formed becomes larger than a length, in the conveyance direction MD, of the opposite surface of the surface on which the raised regions PA, PB are formed. 
         [0076]    Therefore, a difference in the curvature radius at the conveyance roller  2  can be absorbed, and the sheets  71 ,  72  can be conveyed stably, by conveying the sheets  71 ,  72  while changing the direction at the conveyance roller  2 , in a state where the surface having the raised regions, on which PA, PB are formed, is arranged on the non-conveyance-device-contact surface side. 
         [0077]    Further, by impregnating the sheets  71 ,  72  with the predetermined chemical before bringing the folded sheets  71 ,  72  in contact with the surface of the conveyance roller  2 , the predetermined chemical can be intervened between the surface having the raised regions PA, PB formed thereon, and the opposite surface, so that these surfaces can be bonded to each other appropriately, and the sheets  71 ,  72  can be conveyed stably without the folding of the raised regions PA, PB returning to its original position. 
         [0078]    In a case where the sheets  71 ,  72  include a water-absorbing fiber, such a fiber becomes soft when absorbing water, and therefore, slack easily occurs in the sheets  71 ,  72 . 
         [0079]    In view of such a situation, in the manufacturing method and the manufacturing apparatus  10  according to the present embodiment, the predetermined chemical is applied to the folded sheets  71 ,  72  from the conveyance-device-contact surface side (that is, the opposite surface side of the surface having the raised regions PA, PB formed thereon). 
         [0080]    The sheets  71 ,  72  cause slack due to the predetermined chemical, on the opposite surface of the surface having the raised regions PA, PB formed thereon. Herein, when the surface impregnated with the predetermined chemical (the opposite surface of the surface having the raised regions PA, PB formed thereon) side is brought in contact with the surface of the conveyance roller  2 , the surface, which has the raised regions PA, PB formed thereon, and is less affected by slack due to impregnation of the predetermined chemical, presses the sheets  71 ,  72  in the thickness direction, so that the sheets  71 ,  72  can be conveyed while stabilizing shapes of the raised regions PA, PB. 
         [0081]    Further, in a case where regions  35 A,  35 B are formed in the opposite surface of the surface on which the raised regions PA, PB are formed, the aforementioned raised regions PA, PB are formed in positions which do not correspond to the regions  35 A,  35 B. This makes it easy to obtain adhesiveness by the predetermined chemical. 
         [0082]    As described above, the present invention has been described in detail by using the above-described embodiment. However, it is apparent to those skilled in the art that the present invention is not limited to the embodiment described in this description. The present invention can be modified and changed without departing from the gist and the scope of the present invention defined by the appended claims. Therefore, the description is aimed at illustration and explanation of the present invention, and does not have any meaning which limits the present invention. 
         [0083]    The entire contents of Japanese Patent Application No. 2010-84588 (filed on Mar. 31, 2010) are incorporated in the present specification by reference. 
       INDUSTRIAL APPLICABILITY 
       [0084]    As described above, according to the present invention, it is possible to provide a method and an apparatus for manufacturing wet wipes, by which a sheet folded back at a non-conveyance-device-contact surface side can be conveyed stably. 
       REFERENCE NUMERALS 
       [0000]    
       
           10  . . . Manufacturing apparatus 
           1  . . . Impregnating unit 
           2  . . . Conveyance roller 
           3 ,  9  . . . Conveyor 
           4  . . . Cutting unit 
           5  . . . Folding unit 
           6  . . . Pile roller 
           71 ,  72  . . . Sheet