JP6018527B2 - Heat sealing equipment - Google Patents

Description

  The present invention relates to a heat seal device used for manufacturing disposable absorbent articles.

  Conventionally, heat sealing devices have been used in the manufacture of pants-type disposable diapers. In the heat sealing device, two seal processing portions (long in the axial direction of the rotation portion) that are respectively provided and heated in the two rotation portions. A heat-sealing process is performed by sandwiching a laminated body of sheets, which is a workpiece, between the sealing parts (see, for example, Patent Document 1 as such a heat-sealing device).

JP 2011-161796 A

  By the way, in the heat seal apparatus that conveys the sheet stack along the outer peripheral surface of the rotating unit, the sheet stack of the rotating unit is not included in the period between the two seal processing units. In order to contact the processing surface, depending on various conditions in the heat sealing apparatus, there is a possibility that a part that contacts the processing surface melts and a hole penetrating all or part of the sheets of the laminate is formed. In this case, the adhesive area between the sheets included in the laminate is reduced, and the adhesive strength between the sheets in the continuous sheet is reduced.

  This invention is made | formed in view of the said subject, and it aims at preventing the adhesive strength between sheets falling in the heat-sealing process in a heat-sealing apparatus.

  The invention according to claim 1 is a heat seal device used for manufacturing a disposable absorbent article, wherein the first seal processed portion that extends in parallel with the first central axis and is heated, and the first central axis A pair of abutting portions that abut against the continuous sheet in the vicinity of both sides of the first seal processing portion in the circumferential direction centered on the first sheet, and rotating about the first central axis, A first rotating portion that conveys along a circumferential direction; a second seal processing portion that extends in parallel with a second central axis parallel to the first central axis and that is heated; and centered on the second central axis A second rotating part that rotates in a direction opposite to the rotating direction of the first rotating part, and the second seal rotates in synchronization with the rotation of the first rotating part, whereby the first seal Between the processing part and the second seal processing part A plurality of target portions of the continuous sheet are sequentially sandwiched, heat sealing processing is performed on a plurality of absorbent articles, each of which is a part of the continuous sheet, and between the pair of contact portions in the circumferential direction. With the direction passing through the center and perpendicular to the first central axis as the direction of interest, the target portion of the continuous sheet between the pair of contact portions is the first seal processing portion and the second seal processing portion. At the time of non-processing that is not sandwiched between, the distance in the attention direction between the position of the continuous sheet and the first central axis at one of the pair of contact portions is the first center axis. It is larger than a reference distance which is a distance in the direction of interest between the processing surface of one seal processing portion and the first central axis.

  Invention of Claim 2 is the heat-sealing apparatus of Claim 1, Comprising: The heat seal process by which the said object site | part is pinched | interposed between the said 1st sealing process part and the said 2nd sealing process part At both the time and the non-working time, the distance in the attention direction between the position of the continuous sheet and the first central axis at the one abutting portion is larger than the reference distance, The distance in the direction of interest between the position of the continuous sheet and the first central axis at the contact portion is approximately equal to the reference distance.

  A third aspect of the present invention is the heat sealing apparatus according to the second aspect, wherein the one abutting portion is a front abutting portion in the rotational direction of the pair of abutting portions.

  According to the present invention, it is possible to prevent the target portion from being excessively heated at the time of non-processing and reducing the adhesive strength between the sheets by suppressing the target portion from contacting the first seal processing portion during non-processing. can do.

  In the invention of claim 2, it is possible to improve the adhesive strength by reducing the extension amount of the target part at the time of heat sealing, and in the invention of claim 3, the adhesive strength in the target part is at the front part and the rear part. Can be suppressed.

It is a figure which shows the structure of a heat seal apparatus. It is a figure which shows the 1st seal | sticker process part vicinity. It is a figure which shows a 2nd sealing process part. It is a figure which shows the 1st seal processing part and the 2nd seal processing part in the seal processing position vicinity. It is a figure which shows the 1st seal processing part and 2nd seal processing part in a seal processing position. It is a figure which shows the heat seal apparatus of a comparative example. It is a figure which shows the other example of a heat seal apparatus. It is a figure which shows the 1st seal processing part and the 2nd seal processing part in the seal processing position vicinity. It is a figure which shows the 1st seal processing part and 2nd seal processing part in a seal processing position.

  FIG. 1 is a diagram showing a configuration of a heat seal device 1 according to an embodiment of the present invention. The heat sealing apparatus 1 includes a drum 2 that is a rotating unit that rotates around a predetermined central axis J1 by a motor (not shown). Above the drum 2 in FIG. 1, a processing unit 3 that performs heat sealing processing on the continuous sheet 9 is provided. Auxiliary rollers 61 and 62 are provided on the left and right sides of the drum 2 to rotate about center axes J3 and J4 parallel to the center axis J1, respectively. A continuous sheet 9 in which a plurality of disposable diapers in the process of manufacture are continuously hung on the auxiliary roller 61, the drum 2 and the auxiliary roller 62 in order, and the drum 2 centering on the central axis J1 near the position facing the processing unit 3. It is held on the outer peripheral surface 210. The drum 2 in FIG. 1 rotates counterclockwise, and the auxiliary rollers 61 and 62 rotate clockwise. In FIG. 1, the rotation direction of the drum 2 and the auxiliary rollers 61 and 62 is indicated by arrows denoted by reference numerals R1, R3, and R4. The diameter of the drum 2 in the heat sealing apparatus 1 is, for example, 500 to 1000 mm (millimeter).

  On the outer peripheral surface 210 of the drum 2, a plurality of (two in FIG. 1) grooves 211 that are long in the direction of the central axis J <b> 1 are formed at equal intervals in the circumferential direction around the central axis J <b> 1. A block-shaped first sealing portion 23 extending in parallel with the central axis J1 is fixed in each groove portion 211. The distance between the surface of the first seal processing part 23 facing away from the central axis J1 and the center axis J1 is substantially the same as the radius of the drum 2, and the outer surface of the first seal processing part 23 ( A processed surface 242) of FIG. 2 described later can be regarded as a part of the outer peripheral surface 210 of the drum 2. In the groove portion 211, a pair of contact portions 5 that contact the continuous sheet 9 is further provided. A pair of contact part 5 is arrange | positioned in the groove part 211 so that the 1st sealing process part 23 may be pinched | interposed in the circumferential direction. Each contact portion 5 is fixed to the bottom surface of the groove portion 211 via the fixing member 51. Note that the contact portion 5 may be directly fixed to the drum 2.

  FIG. 2 is a view showing the vicinity of one first seal processing portion 23. As described above, the first sealing portion 23 has a long shape in the direction of the central axis J1 (direction perpendicular to the paper surface of FIG. 2). A lower portion 231 (hereinafter referred to as “lower portion 231”) in FIG. 2 is disposed on the center axis J1 side of the drum 2 in FIG. Hereinafter, the “upper part 232” is disposed on the side opposite to the central axis J1 of the drum 2 (on the outer peripheral surface 210 side). In the following description of the first seal processing section 23, the central axis J1 side (the lower side in FIG. 2) in the first seal processing section 23 provided in the drum 2 is referred to as the lower side and is opposite to the central axis J1. The side (the upper side in FIG. 2) is called the upper side. Further, the vertical direction in FIG. 2 is referred to as “the vertical direction of the first seal processing portion 23”. Precisely, the vertical direction of the first seal processing part 23 is a direction that passes through the center between the pair of contact parts 5 in the circumferential direction and is perpendicular to the central axis J1. In addition, since the 1st seal | sticker process part 23 also rotates centering on the central axis J1 by rotation of the drum 2, the lower part 231 and the upper part 232 in FIG. 2 are not necessarily arrange | positioned at the downward direction of the perpendicular direction, and an upper side, respectively. (The same applies to the description of the second seal processing section 32 described later). The first seal processing portion 23 includes a central axis J1 and has a shape that is approximately plane-symmetric with respect to a plane parallel to the vertical direction of the first seal processing portion 23.

  An uneven pattern 240 for heat seal processing is provided on the surface facing the upper side of the first seal processing portion 23. The concavo-convex pattern 240 has two pattern rows 241 each extending in the longitudinal direction of the first seal processing portion 23 with a gap in the circumferential direction. In the following description, the surface of the concavo-convex pattern 240 is referred to as a “processed surface 242”. In the present embodiment, the processing surface 242 is located on a cylindrical surface including the outer peripheral surface 210 of the drum 2. A hole 233 extending in the longitudinal direction is formed in the first seal processing part 23, and a rod-shaped heater is inserted into the hole 233. In the heat sealing apparatus 1, the processing surface 242 of the first seal processing unit 23 is heated to, for example, 150 to 200 ° C. by the heater. The heater is electrically connected to an external power source via a slip ring (the same applies to the second seal processing section 32 described later).

  The contact portion 5 is a thin plate-like member parallel to the vertical direction of the first seal processing portion 23 and the central axis J1, and has a length over the entire width of the continuous sheet 9 in the central axis J1 direction. A downstream contact portion 5 in the conveyance direction of the continuous sheet 9, that is, an upper end surface of the front contact portion 5 in the rotation direction R1 of the drum 2 is an upstream contact portion 5 in the conveyance direction of the continuous sheet 9, In other words, the first seal processing portion 23 is disposed above the upper end surface of the rear contact portion 5 in the rotation direction R1 of the drum 2 in the vertical direction. More specifically, the upper end surface of the rear contact portion 5 is substantially in the same position as the processing surface 242 in the vertical direction, and the upper end surface of the front contact portion 5 is above the processing surface 242 in the vertical direction. To position. In other words, the end of the front contact portion 5 opposite to the central axis J1 protrudes from the processing surface 242 and the rear contact portion 5 (for example, about 2 mm).

  Thus, the position of the continuous sheet 9 in the contact portion 5 on the front side in the rotation direction R1 (that is, the contact position with the contact portion 5 and the position of the upper end surface of the contact portion 5) and the center. The distance in the up-down direction with respect to the axis J1 is larger than the reference distance that is the average distance in the up-down direction between the processing surface 242 of the first seal processing portion 23 and the central axis J1. As a result, the line segment connecting the contact positions of the continuous sheet 9 in the pair of contact portions 5 does not intersect with the processing surface 242, and is not applied to the processing surface 242 of the first seal processing portion 23 except during heat sealing processing described later. The parts of the continuous sheet 9 that face each other are substantially in non-contact with the processed surface 242.

  The processing unit 3 in FIG. 1 includes a rotating unit 31 that rotates about a central axis J2 that is parallel to the central axis J1 of the drum 2. A plurality of block-like (two in FIG. 1) second seal processing portions 32 extending in parallel with the central axis J2 are provided at equal intervals in the circumferential direction around the central axis J2. The rotating unit 31 in FIG. 1 rotates clockwise. In FIG. 1, the rotation direction of the rotation unit 31 is indicated by an arrow with a reference symbol R2.

  FIG. 3 is a view showing one second seal processing section 32. As described above, the second seal processing portion 32 has a block shape extending parallel to the central axis J2 direction (direction perpendicular to the paper surface of FIG. 3), and a lower portion 321 (hereinafter referred to as “lower portion” in FIG. 3). 321 ”) is disposed on the central axis J2 side of the rotating portion 31 in FIG. 1, and an upper portion 322 (hereinafter referred to as“ upper portion 322 ”) in FIG. . The lower part 321 of the second sealing part 32 is formed with a protruding part 323 that protrudes in the lateral direction in FIG. 3 and extends in the longitudinal direction of the second sealing part 32 (that is, the central axis J2 direction). The projecting portion 323 is attached to the rotating portion 31 of FIG. 1, and the second seal processing portion 32 is fixed to the rotating portion 31.

  The surface 327 facing the upper side of the second seal processing portion 32 in FIG. 3 is a predetermined cylindrical surface C2 centered on the central axis J2 in the state where the second seal processing portion 32 is provided on the rotating portion 31 (in FIG. 1). The surface 327 of the second seal processing portion 32 moves substantially on the cylindrical surface C <b> 2 by the rotation of the rotating portion 31. The cylindrical surface C <b> 2 is in contact with the outer peripheral surface 210 of the drum 2. A groove 326 extending in the longitudinal direction is formed on the surface 327. Further, a hole 324 extending in the longitudinal direction is formed in the second seal processing part 32, and a rod-shaped heater is inserted into the hole 324 to heat the second seal processing part 32. The length in the longitudinal direction of the second sealing portion 32 is substantially equal to the length in the longitudinal direction of the first sealing portion 23 in FIG.

  In the heat sealing apparatus 1 of FIG. 1, the circumferential length of the cylindrical surface C <b> 2 in the processing unit 3 is substantially equal to the circumferential length of the outer peripheral surface 210 of the drum 2. As described above, the drum 2 is provided with the two first seal processing portions 23 at an interval of 180 degrees in the circumferential direction around the central axis J1, and the rotating portion 31 of the processing unit 3 includes the central shaft. Two second sealing portions 32 are provided at intervals of 180 degrees in the circumferential direction centering on J2. Further, the drum 2 continuously rotates at a predetermined rotational speed (rotational speed per unit time) around the central axis J1 in a predetermined rotational direction (counterclockwise in FIG. 1) to rotate the machining unit 3. The part 31 continuously rotates in the direction opposite to the rotation direction of the drum 2 (clockwise in FIG. 1) around the central axis J2 at the same rotational speed as the drum 2. Furthermore, each 1st seal | sticker process part 23 of the drum 2 is a position (namely, the position which connects the central axis J1 and the central axis J2, and the outer peripheral surface 210) which opposes the process unit 3, and hereafter, " The rotation unit 31 rotates in synchronization with the rotation of the drum 2 so that the second seal processing unit 32 also reaches the position when the seal processing position is reached. Therefore, in the very vicinity of the seal processing position, the outer end portion of the first seal processing portion 23 and the outer end portion of the second seal processing portion 32 move in the same moving direction at the same moving speed.

  Next, the operation | movement of the heat seal process in the heat seal apparatus 1 is demonstrated. Here, the continuous sheet 9 processed in the heat sealing apparatus 1 is a laminate (a laminate including a nonwoven fabric sheet) such as a long outer layer sheet or an inner layer sheet, and an opening corresponding to a leg opening of a diaper. Are formed at regular intervals in the longitudinal direction of the continuous sheet 9. The absorption core is arrange | positioned in the site | part between two adjacent opening parts, The said site | part is a thing which will become one diaper. Actually, the continuous sheet 9 is folded in two so as to overlap two edges along the longitudinal direction.

  Each part of the continuous sheet 9 conveyed to the heat sealing apparatus 1 in FIG. 1 is guided and held on the outer peripheral surface 210 of the drum 2 by the auxiliary roller 61. At this time, a portion of the continuous sheet 9 (hereinafter referred to as “target portion”) that is approximately at the same position as the center of the opening in the longitudinal direction is disposed between the pair of contact portions 5. Specifically, the target portion of the continuous sheet 9 faces the processing surface 242 (see FIG. 2) of the first seal processing portion 23 extending in parallel to the central axis J1, and the vicinity of both sides of the target portion in the longitudinal direction is the circumference. A pair of contact portions 5 in the vicinity of both sides of the first seal processing portion 23 in the direction. The target portion is transported along the circumferential direction by the rotation of the drum 2 and moves to the vicinity of the processing unit 3. Then, heat sealing processing is performed on the target portion by the processing unit 3.

  FIG. 4 is a view showing the first seal processing portion 23 and the second seal processing portion 32 in the vicinity (immediately before) the seal processing position of the processing unit 3, and FIG. 5 is the first seal processing position of the processing unit 3 in the first processing position. It is a figure which shows the seal process part 23 and the 2nd seal process part 32. FIG.

  In the heat sealing process in the processing unit 3, as shown in FIG. 4, in the uneven pattern 240 of the first seal processing part 23, a pattern row (pattern denoted by reference numeral 241 a in FIG. 4) located on the front side with respect to the rotation direction R <b> 1 of the drum 2. This is a row and is hereinafter referred to as “preceding pattern row 241a”) and comes into contact with the second sealing portion 32 via (continuously) the continuous sheet 9. Thereby, the overlapping portions of the two-fold continuous sheet 9 are heat-sealed at the contact portion with the preceding pattern row 241a, and a seal pattern corresponding to the preceding pattern row 241a is formed at the target portion. At this time, the part between the two contact portions 5 in the continuous sheet 9 is stretched approximately evenly. 4 and 5, the target portion of the continuous sheet 9 at the time of non-processing that is not sandwiched between the first seal processing portion 23 and the second seal processing portion 32 is indicated by a two-dot chain line ( The same applies to FIGS. 8 and 9 described later).

  Subsequently, as shown in FIG. 5, a pattern row located behind the drum 2 in the rotation direction R <b> 1 (a pattern row denoted by reference numeral 241 b in FIG. 5, hereinafter referred to as “following pattern row 241 b”) A seal pattern corresponding to the subsequent pattern row 241b is formed adjacent to the seal pattern of the preceding pattern row 241a by contacting the second seal processing portion 32 via the continuous sheet 9. Actually, when the preceding pattern row 241a comes into contact with the second seal processing portion 32, the subsequent pattern row 241b comes into contact with the target portion.

  When the heat sealing process is performed on the target part in this way, the target part is conveyed to the subsequent cutter unit (not shown) via the auxiliary roller 62 in FIG. Is disconnected. Specifically, the continuous sheet 9 is formed between a portion where heat sealing is performed by the preceding pattern row 241a and a portion where heat sealing is performed by the subsequent pattern row 241b, that is, by the preceding pattern row 241a. Cutting is performed between the seal pattern thus formed and the seal pattern formed by the subsequent pattern row 241b. The part separated from the continuous sheet 9 is collected and becomes one disposable diaper (after subsequent processing is performed if necessary).

  As described above, in the heat sealing apparatus 1, as the drum 2 rotates, a plurality of portions of the continuous sheet 9 are sequentially held on the outer peripheral surface 210 of the drum 2, and heat sealing processing by the processing unit 3 is performed. . In the heat sealing apparatus 1, the plurality of target portions of the continuous sheet 9 are sequentially sandwiched between the first seal processing unit 23 of the drum 2 and the second seal processing unit 32 of the processing unit 3, and each is a continuous sheet. No. 9 is subjected to heat sealing processing (so-called side seal portion formation) for a plurality of disposable diapers.

  FIG. 6 is a view showing a heat seal device of a comparative example, and FIG. 6 shows the vicinity of the first seal processing portion 91. In the heat seal device of the comparative example, the upper end surfaces of the front and rear contact portions 93 in the rotation direction R <b> 1 of the drum 92 are substantially the same position as the processing surface 911 in the vertical direction of the first seal processing portion 91. In other words, the distance in the vertical direction between the position of the continuous sheet 9 and the central axis J1 at the front and rear contact portions 93 is the distance between the processing surface 911 of the first seal processing portion 91 and the central axis J1. It is approximately equal to the distance in the vertical direction (average distance). Therefore, the contact state between the target portion and the processing surface 911 is maintained when the target portion of the continuous sheet 9 is not processed between the first seal processing portion 91 and the second seal processing portion. As a result, depending on various conditions in the heat sealing apparatus of the comparative example, the target portion is excessively heated when not processed, and a hole penetrating all or part of the laminated body in the continuous sheet 9 is formed. And the adhesive strength between sheets may fall.

  On the other hand, in the heat seal device 1, the vertical direction of the first seal processing portion 23 is the direction of interest, and the distance in the direction of interest between the position of the continuous sheet 9 in the front contact portion 5 and the central axis J1 is The target portion of the continuous sheet 9 between the pair of contact portions 5 that is larger than the distance (reference distance) in the direction of interest between the processing surface 242 of the first seal processing portion 23 and the central axis J1. However, it will be in a substantially non-contact state with the process surface 242. Thus, by suppressing that a target part contacts the 1st seal process part 23 at the time of non-processing, a target part is heated too much at the time of non-processing, and the adhesive strength between the sheets in a target part falls. Can be prevented.

  FIG. 7 is a view showing another example of the heat sealing apparatus 1, and FIG. 7 shows the vicinity of the first sealing portion 23. In the heat seal device 1 of FIG. 7, the upper end surface of the rear contact portion 5 is the processing surface in the vertical direction of the first seal processing portion 23, as with the front contact portion 5 in the rotation direction R <b> 1 of the drum 2. Located above 242. That is, in both the front and rear contact portions 5, the end on the opposite side to the central axis J <b> 1 protrudes from the processing surface 242. Other configurations are the same as those in FIG.

  With the up-and-down direction of the first seal processing portion 23 as the attention direction, the distance in the attention direction between the position of the continuous sheet 9 and the central axis J1 in both contact portions 5 is the processing surface 242 of the first seal processing portion 23. And a reference distance that is a distance in the direction of interest between the center axis J1 and the center axis J1. Thereby, the part of the continuous sheet 9 that faces the processing surface 242 of the first seal processing unit 23 is in a non-contact state with the processing surface 242 except during heat sealing processing.

  FIG. 8 is a view showing the first seal processing portion 23 and the second seal processing portion 32 in the vicinity (immediately before) the seal processing position of the processing unit 3, and FIG. 9 is a diagram showing the first seal processing portion at the seal processing position. It is a figure which shows 23 and the 2nd seal process part 32. FIG.

  As shown in FIG. 8, in the heat sealing process, the preceding pattern row 241a abuts on the second sealing portion 32 via the continuous sheet 9, and a seal pattern corresponding to the preceding pattern row 241a is formed at the target portion. . At this time, the continuous sheet 9 is pressed against the preceding pattern row 241a by the second sealing portion 32, so that the portion between the two contact portions 5 in the continuous sheet 9 is stretched approximately evenly. In addition, a gap is generated between the subsequent pattern row 241b and the portion of the continuous sheet 9 facing the subsequent pattern row 241b.

  Subsequently, as illustrated in FIG. 9, the subsequent pattern row 241 b comes into contact with the second seal processing unit 32 via the continuous sheet 9, and a seal pattern corresponding to the subsequent pattern row 241 b is formed in the target portion. At this time, when the continuous sheet 9 is pressed against the subsequent pattern row 241b by the second seal processing section 32, the portion between the preceding pattern row 241a and the rear contact portion 5 in the continuous sheet 9 is further expanded. (This effect will be described later). In the processing unit, the heat sealing process is performed on the target part in this way.

  As described above, in the heat sealing apparatus 1 of FIG. 7, the distance in the attention direction between the position of the continuous sheet 9 and the central axis J1 in both the front and rear contact portions 5 is larger than the reference distance. . Thereby, it can suppress more reliably that the object site | part of the continuous sheet 9 between a pair of contact parts 5 contacts the process surface 242 of the 1st seal | sticker process part 23 at the time of a non-process, However, it is possible to further prevent the adhesive strength from being lowered due to excessive heating during non-processing.

  With respect to the vertical direction of the first seal processing portion 23, in the example of FIG. 2, the position of the continuous sheet 9 is arranged above the processing surface 242 of the first seal processing portion 23 only in the front contact portion 5. FIG. In this example, the position of the continuous sheet 9 is arranged on the upper side of the processing surface 242 in both the front side and rear side contact portions 5, but of course, the position of the continuous sheet 9 only in the rear side contact portion 5. May be arranged above the processing surface 242. That is, in the heat seal apparatus 1, if the position of the continuous sheet 9 in at least one of the contact portions 5 is higher than the processing surface 242 of the first seal processing portion 23, the continuous sheet 9. It is possible to prevent the target portion of the body from being excessively heated when not processed.

  By the way, in the heat sealing apparatus of the comparative example of FIG. 6, the adhesive strength in the seal pattern corresponding to the subsequent pattern row 912b may be lower than the adhesive strength in the seal pattern corresponding to the preceding pattern row 912a. This may be because the second seal processing portion supported by the cylinder mechanism slightly jumps due to an impact when the preceding pattern row 912a collides with the second seal processing portion.

  On the other hand, in the example of FIG. 7, as described above, when the preceding pattern row 241 a comes into contact with the second seal processing part 32 via the continuous sheet 9, the continuous sheet 9 has a space between the pair of contact parts 5. When the subsequent pattern row 241b comes into contact with the second seal processing part 32 via the continuous sheet 9, the portion of the continuous sheet 9 facing the subsequent pattern row 241b is further extended. . That is, the extension amount of the portion where the seal pattern is formed when the seal pattern corresponding to the subsequent pattern row 241b is formed is equal to the extension amount of the portion where the seal pattern is formed when the seal pattern corresponding to the preceding pattern row 241a is formed. It becomes larger than the extension amount. Therefore, when the second seal processing unit 32 moves away from the continuous sheet 9 and the target portion of the continuous sheet 9 contracts, the size of the seal pattern corresponding to the subsequent pattern row 241b becomes the seal pattern corresponding to the preceding pattern row 241a. It becomes slightly smaller than the size of. As a result, the above-described tendency described in the heat sealing apparatus of the comparative example (that is, the adhesive strength in the seal pattern corresponding to the subsequent pattern row tends to be lower than the adhesive strength in the seal pattern corresponding to the preceding pattern row). Therefore, there is a possibility that the difference between the adhesive strength at the rear portion of the target portion corresponding to the subsequent pattern row 241b and the adhesive strength at the front portion of the target portion corresponding to the preceding pattern row 241a may further increase. Actually, the above phenomenon occurs when the position of the continuous sheet 9 in the rear contact portion 5 is above the processing surface 242 regardless of the position of the continuous sheet 9 in the front contact portion 5.

  Therefore, from the viewpoint of suppressing the adhesive strength in the target part from being different between the front part and the rear part, in the rotation direction R1 of the drum 2 of the pair of contact parts 5 as in the example of FIG. Only in the front contact part 5, the distance in the attention direction between the position of the continuous sheet 9 and the central axis J1 is the distance in the attention direction between the processing surface 242 of the first seal processing part 23 and the central axis J1. It is preferable to be larger than (reference distance).

  Further, from the viewpoint of improving the adhesive strength by reducing the extension amount of the target part during the heat sealing process, the position of the continuous sheet 9 in one of the contact portions 5 and the center axis J1 It is preferable that the distance in the attention direction is larger than the reference distance, and the distance in the attention direction between the position of the continuous sheet 9 in the other contact portion 5 and the central axis J1 is approximately equal to the reference distance.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  In the heat sealing apparatus 1, at least one contact is made during both heat sealing processing and non-processing when the target portion is sandwiched between the first sealing processing portion 23 and the second sealing processing portion 32. Although the distance in the direction of interest between the position of the continuous sheet 9 in the part 5 and the central axis J1 is made larger than the reference distance, the distance may be made larger than the reference distance only during non-processing. Such an operation can be realized, for example, by providing a mechanism for moving the contact portion 5 in the direction of interest. As described above, it is important that the distance is larger than the reference distance at least during non-processing in order to prevent the target portion from being excessively heated during non-processing and reducing the adhesive strength.

  Depending on the design of the heat seal device, the second seal processing portion or both the first seal processing portion and the second seal processing portion may be provided with an uneven pattern. That is, in the heat seal apparatus, the unevenness pattern for heat seal processing is provided on at least one of the first seal processing portion and the second seal processing portion, so that heat sealing with a predetermined seal pattern is performed on the continuous sheet 9. It becomes possible. Further, the uneven pattern may be omitted, and the flat processed surfaces may be in contact with each other with the continuous sheet 9 interposed therebetween.

  In the heat sealing apparatus 1, a plurality of processing units may be provided around the drum 2, and a plurality of heat sealing processes may be performed on the target portion.

  The heat seal device 1 may be used for heat seal processing other than the side seal portion in a disposable diaper, and for manufacturing other disposable absorbent articles other than a pants-type disposable diaper.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1 Heat seal apparatus 2 Drum 5 Contact part 9 Continuous sheet 23 1st seal process part 31 Rotation part 32 2nd seal process part 242 Process surface J1, J2 Central axis R1 Rotation direction

Claims (3)

A heat seal device used in the manufacture of disposable absorbent articles,
A pair of first seal processing parts that extend parallel to the first central axis and are heated, and a pair that contacts the continuous sheet in the vicinity of both sides of the first seal processing part in the circumferential direction around the first central axis A first rotating unit that has an abutting part and conveys the continuous sheet along the circumferential direction by rotating about the first central axis;
A second seal processing part that extends parallel to the second central axis and is heated and is parallel to the first central axis; and a direction opposite to the rotation direction of the first rotating part about the second central axis A second rotating part that rotates to
With
As the second rotating portion rotates in synchronization with the rotation of the first rotating portion, a plurality of target portions of the continuous sheet are sequentially sandwiched between the first seal processing portion and the second seal processing portion. A heat sealing process is performed on a plurality of absorbent articles, each of which is part of the continuous sheet,
The target portion of the continuous sheet between the pair of contact portions is a first direction passing through the center between the pair of contact portions in the circumferential direction and having a direction perpendicular to the first central axis as a direction of interest. The position of the continuous sheet and the first central axis in one abutting portion of the pair of abutting portions at the time of non-machining that is not sandwiched between the one sealing portion and the second sealing portion The distance in the attention direction between the first seal processing portion and the first central axis is larger than a reference distance that is a distance in the attention direction between the processing surface of the first seal processing portion and the first central axis. . The heat sealing apparatus according to claim 1,
The continuous sheet in the one abutting portion both in the heat sealing process in which the target portion is sandwiched between the first seal processing portion and the second seal processing portion and in the non-processing time The distance in the direction of interest between the position of the first sheet and the first central axis is greater than the reference distance, and the direction of interest between the position of the continuous sheet and the first central axis in the other contact portion The heat sealing apparatus is characterized in that the distance at is approximately equal to the reference distance. The heat sealing apparatus according to claim 2,
The heat sealing apparatus, wherein the one contact portion is a front contact portion in the rotation direction of the pair of contact portions.

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