WO2016084249A1

WO2016084249A1 - Production method for absorbent articles and production device for absorbent articles

Info

Publication number: WO2016084249A1
Application number: PCT/JP2014/081622
Authority: WO
Inventors: 雅和白石; 宜秀石川
Original assignee: ユニ・チャーム株式会社
Priority date: 2014-11-28
Filing date: 2014-11-28
Publication date: 2016-06-02
Also published as: JP5978405B1; JPWO2016084249A1

Abstract

This production method for absorbent articles has: heating steps (20A, 20B) in which a non-woven fabric (9A) is heated; a printing step (30) in which an image (G) is printed on the non-woven fabric (9A) as a result of ink droplets being discharged from an ink discharge device (32) and being caused to hit the heated non-woven fabric (9A); and a production step in which the non-woven fabric (9A) having the image (G) printed thereon is used and an absorbent article (1) is produced.

Description

Absorbent article manufacturing method and absorbent article manufacturing apparatus

The present invention relates to an absorbent article manufacturing method and an absorbent article manufacturing apparatus.

In a paper diaper as an absorbent wearing article, a pattern or a letter is attached to the outer member of the diaper in order to improve the design on the appearance or make it easy to distinguish the front and rear of the diaper. For example, Patent Document 1 describes performing predetermined color design printing on a paper diaper.

JP 2003-70838 A

Inkjet printing is known as a method for printing an image with good image quality on a diaper. In ink jet printing, an image is printed on a landing portion of ink droplets by ejecting ink droplets from a printing device and landing on a nonwoven fabric constituting a diaper. In consideration of using such a nonwoven fabric as a diaper, it is necessary that the printed image has sufficient friction resistance and the like. However, since non-woven fabrics are generally composed of intertwined fibers, ink droplets ejected from a printing apparatus are unlikely to enter the inside of the non-woven fabric. For this reason, there is a possibility that the ink is easily detached from the surface of the printed image, and the fixing property of the ink becomes insufficient.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an absorbent article using a nonwoven fabric with improved ink fixability.

The main invention for achieving the above object is:
A method of manufacturing an absorbent article, a heating step of heating a nonwoven fabric, a printing step of printing an image on the nonwoven fabric by discharging ink droplets from an ink ejection device and landing on the heated nonwoven fabric, The manufacturing method of manufacturing an absorbent article using the nonwoven fabric on which the image is printed.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

According to the present invention, since the gap between the fibers is widened by heating, the ink easily enters the widened gap, and the ink is entangled with the fibers and the ink is solidified between the fibers, thereby improving the fixing of the ink. be able to.

It is a schematic perspective view of the underpants type diaper 1 as an example of the absorbent article which concerns on this embodiment. It is the schematic plan view which looked at the diaper 1 of the unfolding state from the skin side. It is a schematic perspective view which decomposes | disassembles and shows the diaper 1 of an unfolding state. It is a schematic side view of manufacturing line LM1 which manufactures the exterior sheet 7 which comprises the diaper 1. FIG. 3 is a side view for explaining the configuration of the stretched portion 10. FIG. FIG. 6 is an AA arrow view of FIG. 5. 7A and 7B are enlarged views of region B in FIG. It is a figure explaining the state of 9 A of low extensibility continuous sheets to which the extending | stretching process was given. It is a structure explanatory view of heating part 20B. It is sectional drawing of the blower outlet. 2 is a side view illustrating a configuration of a printing unit 30. FIG. 4 is an explanatory diagram of a head unit 32 of a printing unit 30. FIG. It is explanatory drawing of the image G before and behind contraction. FIG. 14A and FIG. 14B are cross-sectional views of the nonwoven fabric for explaining the state when ink droplets land on the nonwoven fabric. It is process explanatory drawing after the production | generation of the exterior continuous sheet 7A until completion of the diaper 1. FIG.

At least the following matters will become apparent from the description of the present specification and the accompanying drawings.
A method of manufacturing an absorbent article, a heating step of heating a nonwoven fabric, a printing step of printing an image on the nonwoven fabric by discharging ink droplets from an ink ejection device and landing on the heated nonwoven fabric, And a manufacturing process for manufacturing an absorbent article using the nonwoven fabric on which the image is printed.

According to such a method for manufacturing an absorbent article, the gap between the fibers is widened by heating, so that the ink easily enters the widened gap, and the ink is entangled with the fiber and the ink is solidified between the fibers. Ink fixing can be improved.

In this method of manufacturing an absorbent article, it is desirable that the heating in the heating step be performed on the front and back surfaces of the nonwoven fabric.

According to such a method for manufacturing an absorbent article, the temperature change of the nonwoven fabric can be made uniform by heating both surfaces of the nonwoven fabric.

A method of manufacturing such an absorbent article, wherein the nonwoven fabric is processed so that portions stretched in a predetermined direction and portions not stretched than the stretched portion are alternately arranged in the predetermined direction. It is preferable that the printing step is performed after the processing step.

According to such a method for manufacturing an absorbent article, the ink permeation can be improved because printing is performed on a nonwoven fabric that has been softened by stretching the fibers in the processing step.

In such a method for manufacturing an absorbent article, it is desirable to heat the nonwoven fabric in the processing step.

According to such a method for manufacturing an absorbent article, the nonwoven fabric can be easily stretched by heating the nonwoven fabric in the processing step.

In this method for manufacturing an absorbent article, it is desirable that the heating temperature in the heating step is higher than the heating temperature in the processing step.

According to such a method for manufacturing an absorbent article, the temperature of the non-woven fabric can be gradually increased, and the non-woven fabric can be prevented from growing rapidly.

It is desirable to have a preheating step of heating the nonwoven fabric before the heating step, in the method for manufacturing such an absorbent article.

According to such a method for manufacturing an absorbent article, the temperature change of the nonwoven fabric can be moderated by heating the nonwoven fabric a plurality of times.

In this method of manufacturing an absorbent article, it is desirable that the heating in the preheating step is performed on the front and back surfaces of the nonwoven fabric.

In this method of manufacturing an absorbent article, it is desirable that the heating step includes a step of injecting hot air from one side of the nonwoven fabric surface to the other side to allow the hot air to penetrate.

According to such a method for manufacturing an absorbent article, the nonwoven fabric after the passage of hot air has a wider gap between the fibers, so that the ink is more likely to penetrate.

In this method of manufacturing an absorbent article, when the temperature between one surface of the nonwoven fabric and the other surface of the nonwoven fabric is the internal temperature of the nonwoven fabric, the internal temperature of the nonwoven fabric is the heating step. It is desirable to perform the printing step in a state higher than the internal temperature of the previous nonwoven fabric.

According to such a method for manufacturing an absorbent article, since the nonwoven fabric whose internal temperature after heating is increased includes air heated between the fibers, the printing process is performed in a state where the fibers of the nonwoven fabric are spread. It can be performed.

In this method for manufacturing an absorbent article, it is desirable that the temperature of the ejection port for ejecting the ink droplets from the ink ejection device is lower than the temperature of the nonwoven fabric after the heating step.

According to such a method for manufacturing an absorbent article, in the printing process, the temperature of the ejection port of the ink ejection device can be set to a temperature suitable for printing, and in the heating process, it is suitable for spreading between the fibers of the nonwoven fabric. The temperature can be set to a suitable temperature for each process.

In this method of manufacturing an absorbent article, the heating step is performed while the nonwoven fabric is conveyed in a first direction, and the nonwoven fabric is conveyed in a second direction that is opposite to the first direction. It is desirable to perform a drying step of drying the ink droplets while performing the printing step and transporting the nonwoven fabric in the first direction.

According to such a method for manufacturing an absorbent article, the space along the first direction or the second direction of manufacturing the absorbent article can be further saved.

In this method for manufacturing an absorbent article, the temperature of the nonwoven fabric after the heating step, the temperature of the nonwoven fabric after the printing step, and the temperature of the nonwoven fabric after the drying step are all before the heating step. It is desirable that the temperature is higher than the temperature of the nonwoven fabric.

According to such a method for manufacturing an absorbent article, when the temperature is higher than that of the non-woven fabric before heating, the state in which the fibers of the non-woven fabric are spread is maintained, so that the ink can easily enter and is spread. Since the ink is dried and solidified between the fibers, the fixing of the ink can be improved.

Further, the absorbent article manufacturing apparatus includes a heating unit that heats the nonwoven fabric, and a printing unit that prints an image on the nonwoven fabric by ejecting ink droplets from the ink ejection device and landing on the heated nonwoven fabric. And a manufacturing section for manufacturing an absorbent article using the nonwoven fabric on which the image is printed.

According to such an absorbent article manufacturing apparatus, the gap between the fibers is widened by heating, so that the ink easily enters the widened gap, and the ink is entangled with the fiber and the ink is solidified between the fibers. Ink fixing can be improved.

=== Embodiment ===
First, a basic structure of a pants-type diaper 1 (hereinafter also simply referred to as “diaper 1”) will be described as an example of an absorbent article formed by the sheet member according to the present embodiment. Next, a manufacturing apparatus for the diaper 1 will be described. explain.

<Basic structure of diaper 1>
FIG. 1 is a schematic perspective view of a pant-type diaper 1. FIG. 2 is a schematic plan view of the unfolded diaper 1 as seen from the skin side. FIG. 3 is a schematic perspective view showing the exploded diaper 1 in an exploded state. In the following description, when the diaper 1 is attached to the wearer, the side that should be located on the skin side of the wearer is simply referred to as “skin side”, and on the other hand, the side that is located on the non-skin side of the wearer. The power side is simply called the “non-skin side”.

Diaper 1 is a so-called two-piece diaper. That is, the diaper 1 has an absorbent main body 3 that absorbs excreted fluid such as urine as a first component. And the non-skin side surface of the absorptive main body 3 is provided, and it has the planar view substantially hourglass-shaped exterior sheet 7 which makes the exterior of the diaper 1 as a 2nd component.

The absorbent main body 3 has an absorbent core 3c that absorbs excretory fluid. The absorptive core 3c is formed by molding liquid absorptive fibers such as pulp fibers and liquid absorptive granular materials such as superabsorbent polymers into a predetermined shape (for example, a rectangular shape). The skin side surface of the absorbent core 3c is provided with a liquid-permeable top sheet 4 such as a nonwoven fabric so as to cover the surface. Similarly, the non-skin side surface of the absorbent core 3c is provided with the surface. A liquid-impermeable leak-proof sheet 5 such as a film is provided so as to cover the entire surface.

The exterior sheet 7 is a flexible sheet having a substantially hourglass shape in plan view in the unfolded state of FIG. 2, and the sheet 7 has a thickness direction, a longitudinal direction, and a width direction as three directions orthogonal to each other. ing. The exterior sheet 7 is divided into three

portions

7f, 7b, and 7c with respect to the longitudinal direction. That is, the exterior sheet 7 is formed on an abdominal side portion 7f disposed on the wearer's belly side, a back side portion 7b disposed on the wearer's back side, and a crotch portion 7c disposed on the wearer's crotch. It is divided.

As shown in FIG. 3, a so-called laminate sheet having a two-layer structure is used for the exterior sheet 7. That is, the exterior sheet 7 is a composite sheet having an inner layer sheet 8 that forms an inner layer facing the wearer's skin when the diaper 1 is worn, and an outer layer sheet 9 that forms an outer layer facing the non-skin side when the diaper 1 is worn. is there. The inner layer sheet 8 and the outer layer sheet 9 are bonded together by adhesion or welding while being overlapped in the thickness direction. In this example, the joining portion between the inner layer sheet 8 and the outer layer sheet 9 is welded with a predetermined joining pattern (not shown) formed by discontinuous dispersion.

As the material for the inner layer sheet 8, a stretchable sheet 8 having stretchability in the width direction of the diaper 1 is used. On the other hand, as the material for the outer layer sheet 9, low stretchability is low in the width direction of the diaper 1. An extensible sheet 9 is used. And in the state where the stretchable inner layer sheet 8 is stretched in the width direction to a predetermined stretch ratio such as 2.5 times the natural length (hereinafter also referred to as the stretched state), the stretch is also low stretch in the state stretched in the width direction. The

sheet

8 and 9 are superposed on the outer layer sheet 9 and fixed integrally with the above-mentioned bonding pattern.

Therefore, when the stretched state is released, the inner layer sheet 8 shrinks in the width direction of the diaper 1 based on its own stretchability. At this time, the low stretchable outer layer sheet 9 has a plurality of hooks. The diaper 1 is bent in the width direction, whereby the outer layer sheet 9 quickly follows the contraction of the inner layer sheet 8 to shorten the entire length in the width direction. As a result, in an unloaded state where no external force acts on the diaper 1, the outer sheet 7 is shortened in the width direction as a whole, and the outer surface of the outer sheet 7 is caused by bending of the outer layer sheet 9. It is in a state where there are multiple wings. However, when an external force is applied to the exterior sheet 7 in the width direction, the exterior sheet 7 can be stretched approximately elastically until the wrinkle is fully extended, whereby the exterior sheet 7 of the diaper 1 It has become a specification with elasticity.

Incidentally, the term “stretchability” as used herein refers to the property that when an external force of tension is applied, it stretches approximately elastically in the direction of the external force and contracts approximately elastically when the external force is released. is there.

Note that the stretchable sheet 8 desirably satisfies the following conditions. That is, in the state where both ends in the longitudinal direction of the belt-like sheet having a short dimension of 25 mm are equally gripped with the total length of 25 mm in the short direction, the both ends are each 1.0 (N) as a power point. The elongation (%) when pulled in the longitudinal direction by an external force is an arbitrary value in the range of 50% to 300%, and the residual elongation strain (%) that remains without contracting after the external force is released and contracted However, it is preferable that the value is an arbitrary value in the range of 0% to 40%. More preferably, the elongation rate is an arbitrary value in the range of 70% to 200%, and the residual elongation strain is an arbitrary value in the range of 0% to 30%. Incidentally, the above-mentioned elongation rate (%) is the natural length L0, which is the length of the belt-like sheet at the time of no load before being pulled, from the length L1 of the belt-like sheet when pulled with an external force of 1.0 (N). Is a percentage notation value of a division value (= ΔL1 / L0) obtained by dividing a subtraction value ΔL1 (= L1−L0) obtained by subtracting by the natural length L0. The residual elongation strain (%) is a subtracted value ΔL2 (= L2) obtained by subtracting the natural length L0 before pulling from the length L2 after releasing the external force of 1.0 (N). -L0) is a percentage of the division value (= ΔL2 / ΔL1) obtained by dividing the natural length L0 by the subtraction value ΔL1 (= L1−L0) obtained by subtracting the natural length L0 from the length L1 when pulled by the external force. It is a written value.

Further, the “low stretch sheet 9” is a stretch sheet lower than the stretch sheet 8 described above. That is, the stretch rate (%) when an external force of a predetermined tensile force is applied is lower than the stretch rate (%) of the stretchable sheet 8 described above. Note that the low-extensible sheet 9 desirably satisfies the following conditions. That is, in the state where both ends in the longitudinal direction of the belt-like sheet having a short dimension of 25 mm are equally gripped with the total length of 25 mm in the short direction, the both ends are each 1.0 (N) as a power point. The elongation (%) when pulled in the longitudinal direction by an external force is preferably an arbitrary value in the range of 0% to 20%. More preferably, the elongation rate is an arbitrary value in the range of 0% to 10%.

In the present embodiment, the stretchable sheet 8 and the low-extensible sheet 9 are made of nonwoven fabric. However, the elastic sheet 8 may be constituted by other sheets such as woven fabric.

About the specific example of the nonwoven fabric which can be utilized for the elastic sheet 8, it is appropriate to perform a gear stretching process or the like on a nonwoven fabric having a thermoplastic elastomer fiber exhibiting substantially elasticity and a thermoplastic resin fiber exhibiting substantially inelasticity. Examples of the nonwoven fabric subjected to various stretching treatments. That is, by performing such stretching treatment, if the substantially inelastic thermoplastic resin fibers contained in the nonwoven fabric are plastically deformed or the joints between the fibers are destroyed, the substantially elastic properties of the thermoplastic elastomer fibers can be reduced. The non-woven fabric can be changed to a structure that hardly inhibits general stretch deformation, whereby the stretchability of the non-woven fabric is expressed and the stretchable sheet 8 can be used.

Since such a stretchable sheet 8 is configured in a state where a plurality of fibers are randomly entangled, when viewed microscopically, the stretchable sheet 8 has a structure having a plurality of voids between the fibers. . And on the surface, there are a portion where the fibers are intertwined closely and a portion where the fibers are intertwined roughly. In other words, the stretchable sheet 8 has a structure having a density. Therefore, even when both ends of the elastic sheet 8 are gripped equally in the lateral direction and pulled in the longitudinal direction, the entire region in the lateral direction does not extend evenly, and is partially dense. Becomes larger, and a portion where the gap becomes larger is generated.

Specific examples of the nonwoven fabric that can be used for the low-extension sheet 9 include spunbond nonwoven fabric, meltblown nonwoven fabric, spunbond nonwoven fabric, meltblown nonwoven fabric, and spunbond nonwoven fabric made of fibers such as PE, PP, polyester, and polyamide. The so-called SMS nonwoven fabric, air-through nonwoven fabric and the like can be exemplified. The fiber structure is not limited to a single fiber made of a single thermoplastic resin as described above. The low-extension sheet 9 also has a structure having a plurality of voids between entangled fibers.

As shown in FIG. 3, the absorbent main body 3 is joined at the joint portion J on the skin side of the exterior sheet 7. And the exterior sheet | seat 7 to which the absorptive main body 3 was attached is folded in half by the crotch part 7c, and the abdominal side part 7f and the back side part 7b are overlapped. Then, in this overlapped state, the abdomen side portion 7f and the back side portion 7b are joined at the respective end portions 7eW in the width direction, so that the waist opening HB as shown in FIG. It is made into the form of the underpants type diaper 1 in which the leg periphery opening parts HL and HL were formed.

In the pants-type diaper 1 of the present embodiment, an image G composed of predetermined characters, patterns, characters, etc. is printed on the exterior sheet 7 (see FIG. 1). The image G improves the design on the appearance of the diaper 1 and allows the user to visually recognize information about the diaper 1 (for example, information indicating the product name and the front and back of the diaper 1). .

<Manufacture of diaper 1>
The manufacturing apparatus for the diaper 1 includes a manufacturing line LM1 for manufacturing the exterior sheet 7 and a manufacturing line LM2 for completing the diaper 1. The production line LM1 includes a transport mechanism CV, a stretching unit 10, a heating unit 20, a printing unit 30, a drying unit 40, and a sheet member joining unit 50 (a part of the manufacturing unit). The production line LM2 is a part of the production department.

<Method for manufacturing exterior sheet 7>
FIG. 4 is a schematic side view of a production line LM1 for producing the exterior sheet 7 constituting the diaper 1. The production line LM1 uses a continuous sheet 8A of stretchable sheet 8 (hereinafter also referred to as stretchable continuous sheet 8A) and a continuous sheet 9A of low stretchable sheet 9 (hereinafter also referred to as low stretchable continuous sheet 9A) as materials. Thus, a continuous sheet 7A in which the exterior sheet 7 is continuous in the width direction (hereinafter also referred to as an exterior continuous sheet 7A) is generated.

The transport mechanism CV is a transport unit that continuously transports the stretchable continuous sheet 8A (interior sheet 8), the low-extension continuous sheet 9A (exterior sheet 9), or both along a predetermined transport path. As the transport mechanism CV, for example, a transport roller, a suction belt conveyor having a suction holding function on a belt surface as a placement surface, or the like is used. In the transport mechanism CV of the present embodiment, the low-extension continuous sheet 9A is transported using a transport roller in a state where the low stretchable continuous sheet 9A is aligned in the transport direction while aligning the direction corresponding to the width direction of the diaper 1 with the transport direction. . Similarly, the stretchable continuous sheet 8A is also transported in a line in the transport direction while aligning the direction corresponding to the width direction of the diaper 1 with the transport direction.

In the following description, the above-described transport direction set on the production line LM is also referred to as “MD direction”. The MD direction can be different depending on the type of the sheet, and even the same sheet can be different depending on the conveyance place. One of the two directions orthogonal to the MD direction is referred to as “CD direction”, and the other is referred to as “Z direction”. The CD direction is a direction parallel to the width direction of each sheet, and is a direction perpendicular to the paper surface of FIG. The Z direction is a direction parallel to the thickness direction of each sheet.

・ Preheating process (conveyance rollers 13, 14)
In the production line LM1, first, preheat treatment is performed to preheat the low-stretch continuous sheet 9A conveyed along the MD direction (conveyance direction). The conveyance rollers 13 and 14 in FIG. 4 are conveyance rollers that constitute the conveyance mechanism CV1, and convey the low-stretch continuous sheet 9A fed from the original fabric roll downstream in the MD direction at a predetermined conveyance speed. The transport rollers 13 and 14 are rotated by a driving force of a motor, and a heater is incorporated in at least one of the transport rollers 13 and 14 or both of the transport rollers 13 and 14 to heat the low-stretch continuous sheet 9A. Thereby, it can heat beforehand before the below-mentioned heating process (preheating), and can make the temperature change of the low-stretch continuous sheet 9A moderate. In addition, by incorporating a heater in the transport rollers 13 and 14, it becomes possible to heat the low-stretch continuous sheet 9A while transporting it, so that absorbent articles can be manufactured efficiently, and the manufacturing facilities and the like are downsized. Is also possible. In the present embodiment, the set temperature of the heater is about 40 ° C., which is equal to or lower than the heating temperature in the heating process. If both the conveying rollers 13 and 14 are equipped with heaters so that both the front and back sides of the low-stretch continuous sheet 9A are heated, the temperature change of the low-stretch continuous sheet 9A is uniform. It becomes easy to.

・ Processing process, heating process (stretching section 10)
The low-extension continuous sheet 9A that has been subjected to the pre-heat treatment is subjected to a processing process in which a stretching process is performed on a part of the region by the stretching unit 10. FIG. 5 is a side view illustrating the configuration of the stretched portion 10. 6 is a view taken in the direction of arrows AA in FIG. 7A and 7B are enlarged views of region B in FIG. FIG. 8 is a diagram for explaining the state of the low-stretch continuous sheet 9A that has been stretched.

The stretching unit 10 includes a corrugated roll mechanism 11 and a transport roller 12. The low-extension continuous sheet 9A that has undergone the preheating step is conveyed in the direction from left to right in FIG. 4 (hereinafter, also referred to as “first direction”) by the conveyance mechanism CV and the conveyance roller 12. In the meantime, the corrugated roll mechanism 11 is used to stretch the low-extension continuous sheet 9A. The corrugated roll mechanism 11 has a pair of upper and lower

corrugated rolls

11U and 11D that rotate around a rotation axis along the CD direction with their outer peripheral surfaces facing each other. As shown in FIG. 5, on the outer peripheral surfaces of the corrugated rolls 11U and 11D, crests 11m and troughs 11v are alternately formed along the rotation direction, and the crests 11m and troughs 11v are respectively It extends in the CD direction (that is, the direction of the rotation axis). However, as shown in FIG. 6, the peak portion 11m of one corrugated roll 11U extends continuously in the CD direction, whereas the peak portion 11m of the other corrugated roll 11D has a predetermined position Pk in the CD direction. , Pk, the peak 11m is discontinuous with respect to the CD direction. In addition, the notch may be provided in the peak portion 11m on the corrugated roll 11U side, and the notch may be provided in the peak portion 11m on the corrugated roll 11D side.

In the

corrugated rolls

11U and 11D of the present embodiment, the pitch Pv in the rotational direction of the valley portion 11v and the pitch Pm in the rotational direction of the mountain portion 11m have the same length. When the corrugated rolls 11U and 11D are rotating, the crests 11m and the troughs 11v are slightly spaced so that the crests 11m of one corrugated roll enter the troughs 11v of the other corrugated roll. With each other. In this state, the low extensibility continuous sheet 9A passes along the first direction between the

corrugated rolls

11U and 11D that rotate (see FIG. 5).

FIG. 7A shows a state in which the low-stretch continuous sheet 9A passes between the corrugated rolls in the state where the peak portions 11m and the trough portions 11v of the pair of

corrugated rolls

11U and 11D mesh with each other in the region B of FIG. Represents. The low-extension continuous sheet 9A that is passing is that of the other corrugated roll (corrugated roll 11U) that enters one of the corrugated rolls 11m and 11m of the corrugated roll (corrugated roll 11D) and the valley 11v therebetween. It is deformed into a three-point bend by the mountain portion 11m. At this time, the portion 9A2 that contacts the top surface of the peak portion 11m of one corrugated roll (corrugated roll 11D) in the low-stretch continuous sheet 9A is in contact with the top surface so as not to be relatively movable, and thus is not easily stretched. On the other hand, the portion 9A1 between two adjacent 9A2 and 9A2 is extended based on the intrusion of the mountain portion 11m. As a result, as shown in FIG. 8, in the low-extension continuous sheet 9A, the stretched first portions 9A1 and the second portions 9A2 that are not stretched more than the first portions 9A1 are alternately arranged in the MD direction. It is processed as follows. And in the area | region of 1st part 9 A1, the fiber which comprises the nonwoven fabric of the low extensibility continuous sheet 9A is partially extended or cut | disconnected by the above-mentioned extending | stretching process. Thereby, the intertwined fibers are partially loosened to widen the gaps formed between the fibers, and the flexibility of the low-extension continuous sheet 9A can be increased.

On the other hand, FIG. 7B shows a state in which the low-stretch continuous sheet 9A passes between the pair of

corrugated rolls

11U and 11D at the predetermined position Pk where the cutout is provided in the CD direction in the region B of FIG. The state of is expressed. As shown in FIG. 6, since the peak portion 11m of the corrugated roll 11D is cut out in the region of the predetermined position Pk, the low stretch continuous sheet 9A passing through the region is the peak portion 11m of the corrugated rolls 11U and 11D. Without being sandwiched between them, it is conveyed straight in the MD direction as shown in FIG. 7B. Therefore, in the region at the predetermined position Pk, the low-stretch continuous sheet 9A is not stretched, and the first portion 9A1 is formed so as to be interrupted at the predetermined position Pk in the CD direction, as shown in FIG.

In this way, by partially stretching the low-stretch continuous sheet 9A, which is the printing medium, the fibers of the low-stretch continuous sheet 9A become soft, and ink droplet penetration in the subsequent printing process is improved. Can be made. In the following description, in the low-extension continuous sheet 9A, the surface on the side stretched by the corrugated roll 11D in which the crest 11m has a notch is referred to as “processed surface A” for convenience, and the processed surface A is The surface on the opposite side (that is, the surface stretched by the corrugated roll 11U) is referred to as “processed surface B” for convenience (see FIG. 5).

Also, a heater is incorporated in at least one of the pair of upper and lower

corrugated rolls

11U and 11D of the stretch processing unit 10 to heat the peak portion 11m of the corrugated rolls 11U and 11D. If it does in this way, the fiber of the nonwoven fabric which comprises 9A of low extensibility continuous sheets can be softened by the heating of the peak part 11m. As a result, the fibers are easily stretched, so that the effect of the stretching process in the first portion 9A1 can be further increased, and the breakage of the low-stretchable continuous sheet 9A that can occur during stretching can be suppressed. The set temperature of the heater at this time is preferably higher than the pre-heat treatment temperature and lower than the heat treatment temperature described below. As a result, the temperature of the low-stretch continuous sheet 9A is rapidly increased by the heat treatment performed by the

conveyance rollers

15 and 16 described later and the

heating units

20A and 20B, and the low-stretch continuous sheet 9A is rapidly stretched. Can be suppressed. In the present embodiment, the set temperature of the heater is about 40 ° C. At this time, if the

corrugated rolls

11U and 11D are both equipped with heaters to heat the front and back sides of the low-stretch continuous sheet 9A, the temperature change of the low-stretch continuous sheet 9A becomes more uniform. It becomes easy.

(Conveyance rollers 15 and 16) (heating unit 20A)
The stretchable low-stretch continuous sheet 9A is conveyed downstream in the MD direction, and is heated by the conveying

rollers

15 and 16 while being conveyed in the first direction. The

conveyance rollers

15 and 16 in FIG. 4 are conveyance rollers constituting the conveyance mechanism CV2, and the low-stretch continuous sheet 9A that has been subjected to the processing process is conveyed in the first direction (downward in the MD direction) at a predetermined conveyance speed. Transport. The

conveyance rollers

15 and 16 are rotated by the driving force of the motor, and a heater is incorporated in at least one of the

conveyance rollers

15 and 16 or both of the

conveyance rollers

15 and 16 to heat the low-stretch continuous sheet 9A. The heating unit 20A is configured. At this time, if a heater is incorporated in both the

transport rollers

15 and 16 to heat both the front and back sides of the low-stretch continuous sheet 9A, the temperature change of the low-stretch continuous sheet 9A can be reduced. It becomes easy to make uniform. The heated fibers of the low-stretch continuous sheet 9A are soft and the gaps between the fibers are widened. In addition, by incorporating a heater in the

transport rollers

15 and 16, it becomes possible to heat the low-stretch continuous sheet 9A while transporting it, so that absorbent articles can be manufactured efficiently, and the manufacturing facilities and the like can be downsized. Is possible. At this time, the set temperature of the heater is preferably set to a temperature higher than the heating temperature by the heater built in the corrugated rolls 11U and D described above. In the present embodiment, the set temperature of the heater is about 75 ° C. This set temperature can be appropriately changed according to the type of nonwoven fabric used.

(Heating unit 20B)
The low extensibility continuous sheet 9A subjected to the heat treatment by the

transport rollers

15 and 16 is subsequently transported to the downstream side in the MD direction and subjected to the heat treatment in the heating unit 20B while being transported in the first direction. FIG. 9 is an explanatory diagram of the configuration of the heating unit 20B. The heating unit 20B of the present embodiment is a linear conveyance type drying device that heats the low-extension continuous sheet 9A while conveying the low-extension continuous sheet 9A linearly along the first direction. The heating unit 20 B includes a heating chamber 21, a conveyance support roller 22, a plurality of outlets 23, and a pressurization chamber 24.

The heating chamber 21 is a member that partitions a dry region around the conveyance path of the low-extension continuous sheet 9A. The inside of the heating chamber 21 is kept at a high temperature, and in this embodiment, it is kept at 70 ° C. to 80 ° C., which is about the same as the set temperature of the heaters of the

transport rollers

15 and 16 described above. The low extensibility continuous sheet 9 A is heated in the heating chamber 21. The conveyance support roller 22 is a rotation roller that conveys the low-extension continuous sheet 9 A in the heating chamber 21 while supporting it. The conveyance support roller 22 may be rotated by a driving force of a motor, or may be rotated passively by contacting the low-extension continuous sheet 9A.

The air outlet 23 is a part that blows out heated air (hot air). In the heating unit 20B of FIG. 9, a plurality of outlets 23 are provided for the pressurizing chamber 24 for supplying heating air, and uniform heating air is supplied from each of the outlets 23 toward the low-extension continuous sheet 9A. Can be blown out. In the present embodiment, heated air of about 80 ° C. is blown out. FIG. 10 is a cross-sectional view of the air outlet 23. The blower outlet 23 has a slit-like opening 231 in which an opening having a width W in the MD direction extends in the CD direction. In addition, a narrowed portion 232 and a rectifying portion 233 that serve as a flow path for the heated air are formed inside the air outlet 23. The heated air supplied from the pressurizing chamber 24 flows from the heated air supply hole 23h into the throttle portion 232, moves to the rectifying portion 233 side while being squeezed through the flow path, is rectified, and is then ejected from the opening portion 231. The Thereby, the blower outlet 23 can spray heating air to the whole area | region of the width direction (CD direction) of the low extensibility continuous sheet 9A.

In the heating unit 20B of the present embodiment, heated air is sprayed from the lower side to the upper side in the thickness direction on the low-extension continuous sheet 9A. That is, heated air is sprayed from the processing surface A side of the low-extension continuous sheet 9A (see FIGS. 4 and 9). The sprayed heated air flows so as to penetrate the low-extension continuous sheet 9A in the thickness direction, and heats the inside of the low-extension continuous sheet 9A. In addition, when heated air penetrates the low extensibility continuous sheet 9A which consists of a nonwoven fabric, the space | interval (space | gap) between the intertwined fibers becomes a flow path of heated air. In this embodiment, since the said space | gap is expanded by the extending | stretching process by the extending | stretching process part 10, heated air is easy to flow through a nonwoven fabric. Thereby, the space | gap of a nonwoven fabric is expanded more. In particular, on the processed surface A side of the nonwoven fabric to which the heated air is sprayed, the voids are likely to widen, so that the ink discharged in the printing process described later is easily fixed. Further, since the air between the intertwined fibers is warmed by the passage of the heated air, the inside of the nonwoven fabric is in a state of being hot and can be kept warm until a printing process described later is performed. In addition, this heating part 20B may be arranged with the air outlet 23 so that the heated air is jetted from the upper side to the lower side in the thickness direction of the low-extension continuous sheet 9A. It is good also as what arrange | positions the blower outlet 23 so that heated air may blow off from both lower sides.

In the present embodiment, contact heating that heats the conveying

rollers

15 and 16 with built-in heaters and the low-stretch continuous sheet 9A in contact with each other, and non-contact heating that blows and heats the heating air of the heating unit 20B. Although heat processing was performed, the heat processing may perform both contact heating or non-contact heating, and any one may be sufficient as it. In the contact heating, since the heat source is in direct contact with the surface of the low stretch continuous sheet 9A, the low stretch continuous sheet 9A can be uniformly heated. On the other hand, non-contact heating is suitable for warming the air between the fibers because the heated air penetrates between the fibers.

In addition, about contact heating, it is not restricted to what is built in a conveyance roller, The method of pressing and heating what comprises a heater independently to the low-stretch continuous sheet 9A can also be used. The non-contact heating is not limited to the one in which heated air is blown, and a method such as heating the low stretchable continuous sheet 9A at the atmospheric temperature in the heating chamber 21 can also be used.

・ Printing process (Printer 30)
The low-stretch continuous sheet 9A that has been subjected to the heat treatment is conveyed downstream in the MD direction, and is a right-to-left direction in FIG. 4, which is a direction opposite to the first direction (hereinafter referred to as a second direction) The image G is printed by the printing unit 30 while being conveyed. The printing unit 30 of the present embodiment is an ink jet printing apparatus that ejects ink droplets from a large number of nozzles Nz and forms an image G by ink droplets (dots) landed on the low-extension continuous sheet 9A.

FIG. 11 is a side view showing the configuration of the printing unit 30. FIG. 12 is an explanatory diagram of the head unit 32 of the printing unit 30. The printing unit 30 includes a head unit 32, a transport roller 33, and a printing control unit 34. In the following description, the surface of the low-extension continuous sheet 9A facing the head unit 32 may be referred to as a “printing surface”.

The head unit 32 is an ink discharge unit that has a plurality of nozzles Nz (discharge ports) arranged in the CD direction and discharges ink droplets from each nozzle Nz. The head unit 32 is provided for each color of ink (cyan ink, magenta ink, yellow ink, black ink). A plurality of (here, four) head units 32 are arranged side by side along the MD direction. Each head unit 32 has a plurality (four in this case) of heads 321 arranged in a staggered pattern along the CD direction, and each head 321 has a plurality of nozzles Nz arranged in the CD direction. . Thereby, each head unit 32 can discharge ink to the whole area | region of the width direction of the low extensibility continuous sheet 9A. The head unit 32 may be capable of discharging a plurality of colors of ink. Moreover, the head unit 321 of the head unit 32 may be one, and may be three or more. Further, the ink droplet ejection method by the head 321 may be a piezoelectric method using a piezoelectric element, a thermal method using a heater, or another method.

The conveying roller 33 is a rotating roller that conveys the low-extension continuous sheet 9A. The conveyance roller 33 supports the low extensibility continuous sheet 9 A in the thickness direction, so that the interval between the nozzle Nz of the head unit 32 and the low extensibility continuous sheet 9 A is maintained. The transport roller 33 is disposed at a position not facing the nozzle Nz of the head unit 32. This is because the low-extension continuous sheet 9A, which is a printing medium, is a nonwoven fabric, and ink droplets may pass between the fibers of the nonwoven fabric.

Further, as shown in FIG. 11, the transport roller 33 may be disposed at a position between the

head units

32 and 32 in the MD direction, and thus the interval between the transport rollers 33 arranged adjacent to each other in the MD direction. By shortening, it becomes easy to suppress the low extensibility continuous sheet 9A from being bent during conveyance.

The printing control unit 34 is a control unit that controls the operation of the printing unit 30. For example, the print control unit 34 controls the ejection timing, the ejection amount, and the like of the ink droplets ejected from each nozzle Nz of the head unit 32 by controlling the head unit 32. Further, the print control unit 34 may control the temperature in the printing unit 30 and each nozzle Nz using a cooling device or the like (not shown). If the temperature of the printing unit 30 and each nozzle Nz is lower than the temperature of the low-stretch continuous sheet 9A that has been subjected to heat treatment, the ink may harden in the printing unit 30 and the apparatus within the printing unit 30. It becomes easy to suppress the alteration. Therefore, it is preferable to set the temperature in the printing unit 30 and each nozzle Nz to a temperature suitable for storing and discharging ink. In this embodiment, the temperature in the printing unit 30 is set in advance to 20 ° C. to 30 ° C., and the temperature of each nozzle Nz is set to about 20 ° C. In addition, since the ink droplets can be satisfactorily ejected from each nozzle Nz at a temperature suitable for printing on the low-stretch continuous sheet 9A that has been heated by the above-described heating and the gaps between the fibers are widened, the ink can be discharged. It penetrates between the fibers of the low-stretch continuous sheet 9A, and the image G can be printed well.

By the way, after the stretchable continuous sheet 8A and the low stretchable continuous sheet 9A stretched in the first direction are bonded together in a sheet member joint portion (see FIG. 4) described later, the stretched state is released. As the stretchable continuous sheet 8A shrinks in the MD direction (width direction of the diaper 1; see FIG. 2), the low stretchable continuous sheet 9A shrinks in the MD direction while forming a plurality of wrinkles. . In consideration of the shrinkage, the printing unit 30 prints the image G on the low-extension continuous sheet 9A. FIG. 13 is an explanatory diagram of the image G before and after contraction. The upper diagram of FIG. 13 is an explanatory diagram of the final image G after contraction. The lower diagram of FIG. 13 is an image G printed on the low-extension continuous sheet 9A, and is an explanatory diagram of the image G before contraction. For example, when the expansion ratio of the stretchable continuous sheet 8A is 1.5 times, an image G (see the lower diagram) is generated by expanding the image G to be printed (see the upper diagram) by 1.5 times in the MD direction. At the same time, the image G stretched in the MD direction is inkjet printed on the low-stretch continuous sheet 9A. The image G (see the figure below) expanded in the MD direction may be generated by the print control unit 34, or may be generated by an external image processing apparatus and transmitted to the print control unit 34.

Since the printing unit 30 performs printing using the low stretchable continuous sheet 9A having a small stretch rate as a printing medium, it is easy to form a good image G. Assuming that inkjet printing is performed using the stretchable continuous sheet 8A as a printing medium, the stretchable continuous sheet 8A is stretched during transport, so that a gap (gap) between the fibers on the surface is likely to widen. As a result, the deviation of the landing positions of the ink droplets may increase, or the ink droplets may pass through the back side of the stretchable continuous sheet 8A, making it difficult to print an image G with good image quality. On the other hand, the low-stretch continuous sheet 9A has a smaller gap between the fibers than the stretchable continuous sheet 8A, and the surface is easily maintained in a uniform state. The image quality of the image G can be made favorable.

On the other hand, when ink jet printing is performed on a nonwoven fabric having a relatively small gap (gap) between fibers, such as the low-extension continuous sheet 9A, ink droplets that have landed on the printing surface side tend to stay on the surface of the nonwoven fabric, and the printing medium Ink may be difficult to fix. The term “ink fixing” as used herein means that the ink is solidified between the fibers of the low-stretch continuous sheet 9A and has a friction resistance which is a state in which the ink is not easily detached. Therefore, in the production line LM1 of the present embodiment, the low-extension continuous sheet 9A is subjected to a stretching process by the stretching unit 10 and a heating process by the heating unit 20A and the heating unit 20B before performing inkjet printing. Thus, the fixing property of the ink droplets is improved by partially widening the gap between the fibers and allowing the ink droplets to enter between the fibers.

FIG. 14 is a cross-sectional view of a non-woven fabric for explaining the state when ink droplets land on the non-woven fabric. FIG. 14A shows the behavior of ink droplets when inkjet printing is performed on a low-extension continuous sheet 9A that is not heated or the like as a comparative example. In the case of FIG. 14A, the ink droplets that have landed on the surface of the nonwoven fabric are stopped by the intertwined fibers, and the ink droplets overlap the surface of the nonwoven fabric. That is, it is difficult for ink droplets to enter the inside of the nonwoven fabric. Therefore, when the surface (printing surface) on which the image G is printed is rubbed, there is a possibility that the ink overlapping the surface may be easily detached. Considering the use as the diaper 1, there is a possibility that the user may touch the printing surface. Therefore, it is inappropriate to use the sheet member on which the image G is easily peeled off as described above as the material of the diaper 1. It is. Further, when ink droplets accumulate on the surface of the printing surface, it takes time to dry the ink, and the apparatus constituting the production line LM1 in the process in which the low-extension continuous sheet 9A is conveyed downstream from the printing unit 30 in the MD direction. There is also a possibility that the ink that has not been dried adheres to (for example, the conveyance roller or the sheet member joining portion).

On the other hand, FIG. 14B shows the behavior of ink droplets when ink jet printing is performed on the low-extension continuous sheet 9A that has been subjected to heat treatment or the like in the present embodiment. In the case of FIG. 14B, since the gap (gap) between the fibers of the nonwoven fabric is widened as described above, the ink droplets that have landed on the surface of the nonwoven fabric can easily enter the inside of the nonwoven fabric through the widened gap. . Then, the fibers sequentially collide with the fibers of the nonwoven fabric while proceeding in the thickness direction from the surface of the nonwoven fabric to the opposite surface, and adhere to the fibers while being split at the collision portion. That is, the ink droplets that have landed on the surface of the nonwoven fabric adhere to the fibers inside the nonwoven fabric while gradually reducing its size. Accordingly, it is difficult for ink droplets to remain on the surface of the nonwoven fabric, and the friction resistance is improved. Further, since the size of the ink droplet is gradually reduced inside the nonwoven fabric (because the amount of ink is reduced), the ink is easily dried. Thereby, the fixability of the ink with respect to a nonwoven fabric can be improved. In FIG. 14B, the ink droplets that have entered the inside of the nonwoven fabric are drawn so as to maintain a spherical shape, but the ink droplets that actually permeate the inside of the nonwoven fabric are attached to the entangled fibers and shaped. However, the spherical shape is not always maintained.

In addition, since heated air is blown to the processing surface A side in the heating unit 20B, the clearance between the fibers is wider on the processing surface A side than on the processing surface B side, so that the ink is easily fixed. Therefore, by performing ink jet printing on the processed surface A side, it is possible to further improve the ink fixability. Of course, it is also possible to perform ink jet printing on the processed surface B side, and even in that case, it is possible to improve the fixing property of the ink.

・ Drying process (drying part 40)
The drying unit 40 is provided downstream of the printing unit 30 in the MD direction, in a position where the low-extension continuous sheet 9A is dried while being conveyed in the first direction, and the image G printed on the low-extension continuous sheet 9A Allow the ink to dry. The configuration of the drying unit 40 is basically the same as the configuration of the heating unit 20B (see FIG. 9). That is, the drying unit 40 includes a drying chamber, a conveyance support roller, a plurality of air outlets, and a pressure chamber (all not shown). Since the function and configuration of the drying unit 40 are substantially the same as those of the heating unit 20B, a detailed description of the structure of the drying unit 40 is omitted here.

In the drying section 40, drying air is blown against the printing surface (that is, the processed surface A side) of the low-extension continuous sheet 9A to pass in the thickness direction, thereby drying the ink that has penetrated into the nonwoven fabric. Since the amount of ink adhering to the fiber is larger as it is closer to the printing surface, the ink is easily dried by disposing the air outlet on the printing surface side of the low-extension continuous sheet 9A. The drying air is a gas for drying the ink forming the image G. The drying air is here dehumidified heated air, but it may be heated air or unheated dehumidified air.

Further, the drying unit 40 may be other than the linear conveyance type drying apparatus as shown in FIG. For example, while holding the low-extension continuous sheet 9A on the outer peripheral surface of the rotating drum, the low-extensibility can be obtained by sucking the drying air ejected from the plurality of outlets arranged around the drum into the drum. A drum-type drying device that allows drying air to pass in the thickness direction of the continuous sheet 9A may be used. In such a drum-type drying apparatus, since drying is performed in a state where the low-extension continuous sheet 9A is adsorbed on the outer peripheral surface of the drum, it is easy to suppress bending of the low-extension continuous sheet 9A being conveyed. Become.

By quickly drying the image G formed on the low-extension continuous sheet 9A by the drying unit 40, the low-extension continuous sheet 9A can be easily handled, and the transport mechanism CV4 is provided in the downstream area in the MD direction of the printing unit 30. It is possible to effectively suppress the ink from adhering to the five conveying rollers and the sheet member joining portion 50.

In the present embodiment, the low-stretch continuous sheet 9A is heated while being conveyed in the first direction, and is conveyed in the second direction opposite to the first direction in which the heat treatment is performed. By performing the printing process and performing the drying process while transporting in the first direction, which is the same direction as the heat process, it is possible to manufacture the absorbent article in a space-saving manner. However, each process may be performed in the same direction.

・ Manufacturing process (Manufacturing Department)
(Sheet member joint 50) (part of the production department)
The low-extensible continuous sheet 9A on which the image G is printed and the printed surface is dried is joined to the stretchable continuous sheet 8A in the thickness direction in the sheet member joining portion 50. The sheet member joining portion 50 of the present embodiment is an ultrasonic welding apparatus having an anvil roller 51 and an ultrasonic horn 52 (see FIG. 4).

On the anvil roller 51 of the sheet member joint portion 50, a stretchable continuous sheet 8A that is stretched in the MD direction at a predetermined stretch ratio (for example, 2.5 times the natural length) and a stretched state in the MD direction ( 9A of low extensibility continuous sheet | seats of the state which gave tension | tensile_strength of the grade which does not deform plastically are supplied. The stretchable continuous sheet 8A and the low stretchable continuous sheet 9A are wound around the outer peripheral surface of the anvil roller 51 in a state where the stretchable continuous sheet 8A and the low stretchable continuous sheet 9A are overlapped in the thickness direction. The extensible continuous sheet 9A is welded when passing through the ultrasonic horn 52, and the exterior continuous sheet 7A is generated.

As shown in FIG. 4, in this embodiment, the stretchable continuous sheet 8A is joined to the surface opposite to the printing surface (the surface on which ink droplets are ejected) of the low stretchable continuous sheet 9A. Thereby, poor welding due to ink can be suppressed, and the bonding strength between the stretchable continuous sheet 8A and the low stretchable continuous sheet 9A can be kept strong. The printing surface of the low-extension continuous sheet 9A is disposed on the opposite side of the stretchable continuous sheet 8A, so that the printing surface of the low-extension continuous sheet 9A is the non-skin side of the exterior sheet 7 of the diaper 1, that is, Since it is arranged on the outermost surface (outermost surface) of the diaper 1 (see FIG. 3), the image G of the exterior sheet 7 of the diaper 1 can be visually recognized in a colorful manner. As described above, since the image G printed by the ink jet printing of the present embodiment has good friction resistance, even if the printing surface is arranged on the outermost surface of the diaper 1, the image is not easily deteriorated and a problem arises. Hateful.

Further, as shown in FIG. 4, when the stretchable continuous sheet 8A and the low stretchable continuous sheet 9A are superimposed on the outer peripheral surface of the anvil roller 51, the low stretchable continuous sheet 9A is set to the inside (anvil roller 51 side). The elastic continuous sheet 8A is on the outside (the ultrasonic horn 52 side). Thereby, since the ultrasonic horn 52 does not touch the printing surface of the low-extension continuous sheet 9A, ink contamination of the ultrasonic horn 52 can be suppressed.

FIG. 15 is a process explanatory diagram from the generation of the exterior continuous sheet 7A to the completion of the diaper 1. In the production line LM2 for completing the diaper 1, first, an opening serving as a leg opening HL (see FIG. 1) is formed in the exterior continuous sheet 7A. This opening is formed by being punched from the exterior continuous sheet 7A by an annular cutter blade (not shown). Next, the exterior continuous sheet 7A that has been conveyed in the stretched state is contracted in the MD direction. Thereby, wrinkles are formed on the outer surface of the exterior continuous sheet 7A. Next, the absorptive main body 3 is attached between the leg openings HL of the exterior continuous sheet 7A, and the exterior continuous sheet 7A is folded in two. An end seal portion (end portion 7eW in FIG. 1) is formed by welding in the CD direction from the leg opening HL of the exterior continuous sheet 7A folded in half, and the exterior continuous sheet 7A is divided and separated at the end seal portion. Part becomes diaper 1. In the present embodiment, the manufacturing unit includes the sheet member joint 50 and the manufacturing line LM2, but may be modified as appropriate.

=== Other Embodiments ===
As mentioned above, although embodiment of this invention was described, said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. Further, the present invention can be changed or improved without departing from the gist thereof, and needless to say, the present invention includes equivalents thereof. For example, the following modifications are possible.

In the above-described embodiment, a so-called line printer type in which a head unit is fixed is used as an inkjet printing apparatus. However, a serial type inkjet in which a head having a plurality of nozzles arranged in the MD direction reciprocates in the CD direction. A printing device may be used.

In the above-described embodiment, the low-extension continuous sheet 9A is a printing medium, but the printing medium is not limited to this. Inkjet printing may be performed on other nonwoven fabrics such as the stretchable continuous sheet 8A and the exterior continuous sheet 7A. Moreover, although the sheet | seat (low-extension continuous sheet 9A) which comprises the underpants type diaper 1 was a to-be-printed medium, the sheet | seat (nonwoven fabric) which comprises other absorbent articles (for example, sanitary napkins, incontinence pads, etc.) Inkjet printing may be performed.

In the above-described embodiment, the drying air is passed from the printing surface side in the thickness direction of the low extensibility continuous sheet 9A, but the drying air may be passed from the opposite surface. However, the closer to the printing surface, the greater the amount of ink attached to the fibers. Therefore, it is advantageous for drying to pass the drying air from the printing surface side.

In the above embodiment, the heat treatment is performed after the pre-heat treatment, but the pre-heat treatment is not necessarily performed. However, by performing the pre-heat treatment, the nonwoven fabric is heated a plurality of times, the temperature change can be moderated, and the nonwoven fabric can be prevented from growing rapidly.

In the above-described embodiment, the stretching process is performed as part of the heat treatment, but the stretching process is not necessarily performed. However, by performing the stretching process, the fibers of the low-extension continuous sheet 9A can be stretched and softened, so that ink permeation can be improved. In addition, you may perform an extending | stretching process and a heat processing, respectively, like performing a heat treatment after performing the extending | stretching process which does not accompany a heating.

1 disposable diapers (absorbent articles, diapers),
3 Absorbent body, 3c Absorbent core,
4 Top sheet,
5 Leak-proof sheet,
7 exterior sheet, 7A exterior continuous sheet,
7f ventral side, 7b dorsal side, 7c crotch, 7eW end,
8 inner layer sheet (elastic sheet), 8A elastic continuous sheet,
9 outer layer sheet (low stretch sheet) (nonwoven fabric), 9A low stretch continuous sheet (nonwoven fabric),
9A1 first part, 9A2 second part,
10 Stretched processing part,
11 corrugated roll mechanism, 11U corrugated roll, 11D corrugated roll,
11v valley, 11m mountain,
12

transport rollers

13, 14, 15, 16 transport rollers (heaters),
20A, 20B heating section,
21 heating chambers, 22 transport support rollers,
23 Air outlet,
231 opening, 232 restrictor, 233 rectifier, 23h heated air supply hole,
24 pressurized chamber,
30 printing department,
32 head units, 321 heads,
33 transport roller, 34 print controller,
40 Drying section,
50 Sheet member joint (manufacturing department),
51 anvil roller, 52 ultrasonic horn,
J joint,
LM1 production line,
LM2 production line (Production Department)
CV transport mechanism,
Nz nozzle (discharge port)

Claims

A method of manufacturing an absorbent article,
A heating step for heating the nonwoven fabric;
A printing step of printing an image on the nonwoven fabric by ejecting ink droplets from an ink ejection device and landing on the heated nonwoven fabric;
A manufacturing process for manufacturing an absorbent article using the nonwoven fabric on which the image is printed.
It is a manufacturing method of the absorptive article according to claim 1,
Heating in the heating step is performed on the front and back surfaces of the nonwoven fabric.
It is a manufacturing method of the absorptive article according to claim 1 or 2,
A processing step of processing the non-woven fabric so that portions stretched in a predetermined direction and portions that are not stretched more than the stretched portion are alternately arranged with respect to the predetermined direction;
The method for producing an absorbent article, wherein the printing step is performed after the processing step.
It is a manufacturing method of the absorptive article according to claim 3,
The method for manufacturing an absorbent article, wherein the nonwoven fabric is heated in the processing step.
It is a manufacturing method of the absorptive article according to claim 3 or 4,
The method for producing an absorbent article, wherein the heating temperature in the heating step is higher than the heating temperature in the processing step.
It is a manufacturing method of the absorptive article according to any one of claims 1 to 5,
The manufacturing method of the absorbent article characterized by having the pre-heating process which heats the said nonwoven fabric before the said heating process.
It is a manufacturing method of the absorptive article according to claim 6,
Heating in the preheating step is performed on the front surface and the back surface of the nonwoven fabric.
It is a manufacturing method of the absorptive article according to any one of claims 1 to 7,
The said heating process has a process which injects a hot air from the one side of the surface of the said nonwoven fabric to the other side, and penetrates the said hot air. The manufacturing method of the absorbent article characterized by these.
A method for manufacturing an absorbent article according to claim 1,
When the temperature between one surface of the nonwoven fabric and the other surface of the nonwoven fabric is the internal temperature of the nonwoven fabric,
The method for producing an absorbent article, wherein the printing step is performed in a state where an internal temperature of the nonwoven fabric is higher than an internal temperature of the nonwoven fabric before the heating step.
It is a manufacturing method of an absorptive article given in any 1 paragraph of Claims 1-9,
The method for producing an absorbent article, wherein a temperature of an ejection port for ejecting the ink droplets from the ink ejection device is lower than a temperature of the nonwoven fabric after the heating step.
It is a manufacturing method of an absorptive article given in any 1 paragraph of Claims 1-10,
While carrying the nonwoven fabric in the first direction, the heating step is performed,
While carrying the nonwoven fabric in a second direction that is opposite to the first direction, the printing process is performed,
A method for producing an absorbent article, comprising performing a drying step of drying the ink droplets while transporting the nonwoven fabric in the first direction.
It is a manufacturing method of the absorptive article according to claim 11,
The temperature of the nonwoven fabric after the heating step;
The temperature of the nonwoven fabric after the printing step;
The temperature of the nonwoven fabric after the drying step is
All are higher than the temperature of the said nonwoven fabric before the said heating process. The manufacturing method of the absorbent article characterized by the above-mentioned.
An absorbent article manufacturing apparatus comprising:
A heating unit for heating the nonwoven fabric;
A printing unit that prints an image on the nonwoven fabric by ejecting ink droplets from an ink ejection device and landing on the heated nonwoven fabric;
A manufacturing section that manufactures an absorbent article using the nonwoven fabric on which the image is printed.