CN107848237B

CN107848237B - Paper cup, method and apparatus for manufacturing the same

Info

Publication number: CN107848237B
Application number: CN201580079219.8A
Authority: CN
Inventors: 门胁贞一
Original assignee: Tokan Kogyo Co Ltd
Current assignee: Tokan Kogyo Co Ltd
Priority date: 2015-03-03
Filing date: 2015-03-03
Publication date: 2021-03-09
Anticipated expiration: 2035-03-03
Also published as: JPWO2016139762A1; KR20180034304A; MY187175A; KR101964833B1; CN107848237A; EP3266603A1; JP5943497B1; WO2016139762A1; EP3266603A4; TW201632417A; TWI633039B

Abstract

The present invention relates to a method and an apparatus for manufacturing a paper cup, and an improvement of the paper cup, wherein embossing is formed on a body of the paper cup or an outer sleeve wound around the outer periphery of the body by a pair of opposed embossing rollers. The embossing device is characterized in that each stamper formed on the surfaces of the pair of embossing rollers has substantially the same shape, and the embossing device comprises: a frame portion composed of a flat surface, which partitions cells surrounded by a lattice frame extending in the longitudinal and transverse directions at regular intervals and intersecting with each other; and a protrusion having four side wall surfaces protruding from four sides of each side of the cell toward a center side of the cell, and a surface or linear apex formed to be integrated at a front end of the side wall surfaces, wherein the pair of dies have the respective protrusions arranged in a direction approaching the blank, and each of longitudinal and lateral lengths of a quadrangle of a unit section including the cell, and intersection portions of a frame portion and a frame portion of two sides extending along adjacent longitudinal and lateral sides of the cell is set to 1 pitch, and the other die is arranged with a half pitch offset in the longitudinal direction with respect to the one die.

Description

Paper cup, method and apparatus for manufacturing the same

Technical Field

The present invention relates to a paper cup in which an outer sleeve is wound around the outer periphery of an inner cup, and the outer sleeve is embossed, a method and an apparatus for manufacturing the paper cup.

Background

Conventionally, paper cups such as paper cups or so-called paper cups have been used. In the paper cup, there is known a paper cup subjected to heat insulating treatment so that not only low-temperature drinking water but also high-temperature drinking water can be accommodated and the outer periphery of the paper cup can be securely held by fingers.

As an example, the heat-insulating paper cup described in patent document 1 has the following structure: a heat insulating sheet made of paper having convex portions and concave portions alternately arranged is wound around the outer periphery of the side wall portion of the paper cup.

With such a heat-insulating paper cup, the heat of the high-temperature content is not easily transmitted directly to the outer periphery of the cup by the convex portions and concave portions formed in the heat-insulating sheet, and thus the outer periphery of the cup can be easily grasped by fingers.

In addition, in order to improve the heat insulating effect, the heat insulating effect can be improved by increasing the height of the convex portions or by making the convex portions dense, but in the case where the convex portions are increased or the convex portions are further densely arranged in the embossing process using the stamper, the blank of the heat insulating sheet is strongly pressed by the stamper, and therefore, there is a possibility that cracks or breakage may occur.

The same problem is also present in the embossed sheet not limited to the unevenness for heat insulation.

That is, conventionally, press working or rolling working using a die composed of a male and female die is used, but in the former press working, a blank cannot be drawn and pushed in sequentially from the front. In addition, in the rolling process, the strongly pressed portion is engaged with the lower die in which the concave-convex of the upper die is inverted without any space, and the blank is stretched, which causes a problem that the blank is easily broken or wrinkled.

Documents of the prior art

Patent document

Patent document 1 Japanese Utility model registration No. 2603108

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above problems, and a main object thereof is to provide a method and an apparatus for manufacturing a paper cup, in which a pair of dies formed on the surfaces of a pair of opposed embossing rollers are arranged in substantially the same shape so that convex portions face each other, the pair of dies are arranged with a half pitch offset in the longitudinal and lateral directions, and a blank passing between the pair of embossing rollers is pressed, whereby embossing for raising the convex portions and for densifying the convex portions is formed on the blank without causing cracks or damages.

Means for solving the problems

In order to solve the above-mentioned problems, with the invention of claim 1,

a method of manufacturing a paper cup by embossing a blank of a trunk portion of the paper cup or an outer sleeve wound around the outer periphery of the trunk portion with a pair of opposed embossing rollers,

the stamper formed on the surfaces of the pair of embossing rollers has substantially the same shape, and the stamper includes: a frame portion formed of a flat surface, the frame portion partitioning cells of each quadrangle surrounded by a lattice frame, the lattice frame extending in a longitudinal direction and a transverse direction at regular intervals and intersecting with each other; and a protrusion having four side wall surfaces protruding from four sides of each side of the cell toward a center of the cell, and a surface formed by collecting front ends of the side wall surfaces or a linear top portion,

the dies of the pair of embossing rollers are arranged such that the respective protrusions are arranged in a direction approaching the blank,

the length of each of the longitudinal and transverse sides of a quadrangle of a unit portion including the cell, the frame portions of the two sides extending along the adjacent longitudinal and transverse sides of the cell, and the intersection of the frame portions is set to 1 pitch, and the other die is arranged with a half pitch in the longitudinal and transverse directions with respect to the one die,

and embossing concave-convex patterns on the blank.

The invention according to claim 2 is characterized in that,

the top of each protrusion of the pair of dies faces in a state of being close to a predetermined intersection portion of the frame portion at the center of four protrusions vertically and horizontally adjacent to the opposite die,

four corner portions of the side wall surfaces of the respective protrusions of the pair of dies are opposed to each other in a state of being brought into close proximity so as to be aligned with corner portions of one part of each of the four protrusions of the die facing each other,

inclined surfaces other than four corners of the side wall surfaces of the protrusions of the pair of dies face the frame portions of the dies facing each other while being inclined,

the frame portions of the pair of dies are opposed to each other in a spaced state at an intersection where the frame portion between a pair of adjacent protrusions in the longitudinal or transverse direction of the pair of dies overlaps with the frame portion between a pair of adjacent protrusions in the transverse or longitudinal direction of the opposite die.

The invention according to claim 3 is characterized in that,

the top portions of the protrusions of the pair of dies are set to have a width within the width of the frame portion where the opposing dies face the top portions.

In addition, in the invention of claim 5,

a device for manufacturing a paper cup, which forms an embossing on a body of the paper cup or a blank of an outer sleeve wound around the outer periphery of the body by a pair of opposed embossing rollers,

and embossing concave-convex patterns on the blank.

Further, in the invention of claim 7,

a paper cup, which is characterized in that embossing is formed on a body of the paper cup or a blank of an outer sleeve wound around the outer periphery of the body by a pair of opposed embossing rollers,

the surface of the blank is provided with: a frame portion that partitions cells of each quadrangle surrounded by a lattice frame that extends in the vertical and horizontal directions at regular intervals and intersects; and a convex portion having a side wall surface which is raised from the surface of the blank to one side toward the center side of the cell from four directions of each side of the cell, and a surface or a linear top portion formed to be gathered at the front end of the side wall surface,

the back surface of the blank is provided with: a frame portion that partitions each of quadrilateral cells surrounded by a lattice frame, the lattice frame extending in a longitudinal direction and a transverse direction at regular intervals equal to a surface of the blank and intersecting the lattice frame, the frame portion being formed in the longitudinal direction and the transverse direction of the frame portion on the surface with a half pitch offset; and a recessed portion which is formed by a side wall surface extending from four sides of each side of the cell toward the center of the cell and protruding from the back surface of the blank to the other side, and a surface or linear bottom portion formed to be integrated with the front end of the side wall surface, and which is formed by being shifted by half a pitch in the longitudinal direction and the lateral direction of the protruding portion on the front surface, and which includes, on the back surface of the blank, an inclined surface in which at least four corners of the side wall surface of the protruding portion and the side wall surface of the recessed portion coincide.

Here, the paper cup is used in a broad sense including a paper cup and a paper container in a cup shape, and includes a paper cup in which a film of various materials is laminated on a base paper.

Effects of the invention

The present invention provides a method and an apparatus for manufacturing a paper cup, in which a front side and a back side of a body of the paper cup or a blank for forming an outer sleeve wound around the outer periphery of the body are forcibly pressed by a pair of embossing rollers, which are arranged so that the protruding portions of the pair of embossing rollers are opposed to each other and are shifted by a half pitch in the longitudinal direction and the lateral direction, thereby making it possible to increase the height of the embossed protruding portions and to form an embossed pattern capable of increasing the density of the protruding portions without causing cracks or damages in the blank.

Drawings

Fig. 1 is a front view illustrating a part of embossing of a paper cup.

Fig. 2 is a front view showing an example of the embossing roller.

Fig. 3 is a side view of a pair of embossing rollers.

Fig. 4(a) is a partial cross-sectional view of a pair of dies for forming embossments, and is a partial cross-sectional view for the upper side of a blank.

Fig. 4(b) is a partial cross-sectional view of a pair of dies for forming embossments, and is a partial cross-sectional view for the lower side of the blank.

Fig. 5 is an expanded view of the stamper as seen from the front surface.

Fig. 6 is a front view showing upper and lower protrusions of the stamper and a part of the frame.

Fig. 7 is an explanatory view showing a part of a stamper for embossing the upper portion of a material in a plan view.

Fig. 8(a) is an explanatory diagram showing a state when a pair of stampers are strongly pressed.

Fig. 8(b) is a diagram illustrating a positional relationship between the pair of stampers indicated by hatching in fig. 8 (a).

Fig. 9(a) is an explanatory view showing a part of one of the dies for embossing the lower portion of the blank, as seen in a plan view.

Fig. 9(b) is an explanatory view showing a part of another stamper for embossing the lower portion of the material in a plan view.

Fig. 10 is an explanatory diagram showing a state in which the pair of stampers in fig. 9 are strongly pressed with hatching.

Fig. 11(a) is a cross-sectional view taken along line x-x of fig. 8 (a).

FIG. 11(b) is a cross-sectional view taken along line y-y of FIG. 8 (a).

FIG. 11(c) is a cross-sectional view taken along line z-z of FIG. 8 (a).

Fig. 11 d is an explanatory view in which a pair of dies in the position of fig. 11 a simultaneously sandwiched (straight) and unclamped are arranged in the horizontal axis direction, and the vertical axis direction is set as the flow direction of the embossing roller.

Detailed Description

Example 1

Fig. 1 is a side view of the paper cup of the present embodiment, where 1 is a paper cup, 2 is an inner cup, 3 is an outer sleeve, 4 is a projection formed on the outer sleeve 3, and 5 is a recess formed on the outer sleeve 3.

As shown in fig. 1, the paper cup 1 of the present embodiment is constituted by a known structure: the outer sleeve 3 subjected to the embossing is wound around the outer periphery of the body portion of the inner cup 2 made of inverted truncated cone shaped paper having an upper opening, but in the present invention, the outer sleeve 3 may not be provided to the paper cup 1, and the body portion of the inner cup may be directly subjected to the embossing.

In the present embodiment, the outer sleeve 3 uses the blank B formed in a fan shape, and the outer sleeve 3 is provided with: convex portions 4 which are surrounded by a plurality of quadrangular frame portions 6 and are regularly arranged in the vertical, horizontal, and right directions, the plurality of quadrangular frame portions 6 being in a lattice shape along the height direction (longitudinal direction) and the lateral direction (circular arc direction) of the paper cup; and a recessed portion 5 (see the die of fig. 5) having a bottommost portion formed at a crossing portion of the frame portion 6.

In order to arrange the projections 4 in a regular array in the vertical direction (longitudinal direction) and the horizontal direction (lateral direction) of the paper cup in the outer sleeve shape, the lateral width of the projection 4 and the lateral width of the frame portion 6 arranged on the upper side of the paper cup of the outer sleeve 3 need to be set so that the widths are reduced stepwise toward the lower side of the paper cup. The vertical width of each convex portion 4 in the vertical row may be the same from top to bottom, or may be gradually shorter in the vertical direction (for example, in the following direction), and the convex portions 4 may have any length if they are regularly aligned.

Further, if the height of the protrusion of the convex portion 4 is formed to be gradually lower from the top to the bottom of the paper cup, it is easy to remove the stacked paper cups one at a time from the bottom or the top.

In the illustrated example, the case where the lattice-shaped frame portion 6 is a square or rectangle whose vertical direction intersects with the horizontal straight angle is exemplified, but in the present invention, the frame portion 6 may be a rhomboid or other quadrangle which intersects at an angle other than the right angle. The longitudinal and transverse arrangement of the projections 4 may be inclined obliquely.

Next, an example of the dies K1 and K2 for forming the convex portions 4 and the concave portions 5 will be described.

The dies K1 and K2 are formed in the same shape and are formed on the surfaces of the pair of embossing rollers R1 and R2, and in the illustrated example, the die K1 is an upper die, the die K2 is a lower die, and the upper die and the lower die are pressed against the material B with a half-pitch lag, which is the opposite of the present invention (see fig. 2 to 6).

For convenience of description, the same reference numerals are given to the same structures in different stampers with a "'" designation for convenience of description.

As partially shown in fig. 7, the stamper K1(K2) includes: the strip-shaped

frame portions

15a and 15b (15a 'and 15 b') each having a flat surface are formed into a vertically and horizontally crossing lattice frame shape; and a protrusion 14 (14') provided with: four side wall surfaces 12 (12') which are inclined and protrude from each side of each cell c of the quadrangle partitioned by the

frame portions

15a, 15b toward the center side of the cell c; and a top portion 13 (13') formed in a planar or linear shape at the upper end of the side wall surface 12.

Here, the cell c coincides with the outer periphery of the base end of the protrusion 14.

As shown in fig. 4(a) and (b), the stamps K1 and K2 are disposed on the pair of embossing rollers R1 and R2 so that the tops 13 and 13 'of the respective protrusions 14 and 14' are offset and face each other.

Fig. 4(a) is a view of the upper side of the paper cup, fig. 4(b) is a view of the lower side of the paper cup where the projections 14 and 14' are formed to have a lower height and a narrower width than the upper side (see fig. 6).

Here, in the present embodiment, the reason for the lateral width being narrow is to set the number of the projections in the upper left and right row to be the same as the number of the projections in the lower left and right row.

The stamps K1 and K2 are arranged such that the lengths L1 and L2 of the rectangular vertical and horizontal lines of the square cells c and the L-shaped frame portions F (hatched portions in fig. 7) along the two sides c1 and c2 adjacent to the vertical and horizontal lines of the cells c and including the intersection points corresponding to the intersection points c3 of the two sides are respectively set to 1 pitch, and the stamps K2 of the other embossing roller R2 are arranged so as to be shifted by half pitch (L1/2, L2/2) in the vertical and horizontal directions with respect to the stamp K1 of the one embossing roller R1, and are used for embossing (see fig. 8).

Thus, the top 13 of the protrusion 14 of one stamper K1 (indicated by a thin line in fig. 8 a) is adjacent to and faces the intersection 15c 'of the frame portions 15 a' and 15b ', the intersection 15 c' is located at the center of the intersection surrounded by the four vertically and horizontally adjacent protrusions 14 'of the opposed stamper K2 (indicated by a thick line in fig. 8 a), the four corners 12c of the side walls 12 of the protrusions 14 of the pair of stampers K1 are arranged so as to be adjacent to and face the adjacent corners 12 c' of the side walls 12 'of the four protrusions 14' of the opposed stamper K2 so as to form inclined surfaces having substantially the same angle (see fig. 11).

Similarly, the top 13 ' of the protrusion 14 ' of the other die K2 is disposed so as to be adjacent to and face the intersection 15c of the

frame portions

15a and 15b, the intersection 15c is located at the center surrounded by the four vertically and horizontally adjacent protrusions 14 in the opposing die K1, and the corner 12c ' of the side wall surface 12 ' of the protrusion 14 ' of the other die K2 is disposed so as to be adjacent to and face the adjacent corner 12c of the side wall surface 12 of the four protrusions 14 of the opposing die K1 so as to form an inclined surface having substantially the same angle.

In the illustrated example, the

corner portions

12c and 12c 'are in a range where the end portions of the adjacent side wall surfaces 12 in one projection are in contact with each other and the projections 14 and 14' can overlap each other so that the ridge extending from the upper end to the lower end of the two side wall surfaces is substantially centered.

In other words, the corner in the illustrated example is formed in a square or rectangular shape when viewed in plan view, and the ridge is located at one diagonal line and includes both surfaces inclined in the longitudinal direction and the lateral direction of the cell c at the boundary of the ridge.

As described above, the blank B is passed between the embossing rollers R1 and R2 of the dies K1 and K2 and pressed strongly, thereby processing the embossing patterns of the concave portions 5 and the convex portions 4.

Here, the protruding portion 14 of one die K1 forms a protruding portion 4 on the front surface of the blank B, and the protruding portion 14' of the other die K2 forms a protruding portion, i.e., a recessed portion 5 when viewed from the front surface side of the blank B, on the back surface of the blank B.

Referring to fig. 8(a) and (b), the portion forcibly pressed by the parallel approach of the top portion 13 of the protrusion 14 and the intersection portion 15c ' of the frame portions 15a ' and 15b ' facing the top portion is the portion a forming the top portion of the convex portion 4 (fig. 8 (b)).

On the other hand, the portion forcibly pressed by the parallel approach of the top portion 13 'of the protrusion 14' and the intersection portion 15c of the

frame portions

15a and 15b opposed thereto is the D portion forming the bottom of the recess 5.

Next, the four corners 12c of the side wall surfaces 12 of the protrusions 14 are adjacent to and pressed substantially in parallel with the adjacent corners 12c ' of the side wall surfaces 12 ' of the four protrusions 14 ' so as to form inclined surfaces having substantially the same angle, and these portions are portions B forming the corners of the side wall surfaces of the protrusions 4 and the corners of the side wall surfaces of the recesses 5 at the same time.

The inclined surface extending in the longitudinal direction and the lateral direction of the ceiling portion 13 at the central portion of the side wall surface 12 other than the four corners 12C of the side wall surface 12 of the protrusion portion 14 is a portion C facing the frame portion 15 b' of the flat surface.

Similarly, the inclined surface extending in the longitudinal direction and the lateral direction of the ceiling portion 13 'at the central portion of the side wall surface other than the four corners 12 c' of the side wall surface 12 'of the protrusion portion 14' is the portion E facing the frame portion 15b of the flat surface.

In the C portion and the E portion, one of the inclined surfaces is close to the horizontal flat surface, and the other is strongly pressed in a state of being separated from the horizontal surface, so that the close side of the blank is slightly pinched and the separated side becomes free.

The portion of the frame portion 15a 'sandwiched between the opposing C portions of the vertically adjacent protrusions 14, that is, the intersection portion of the frame portion 15b sandwiched between the opposing E portions of the laterally adjacent protrusions 14', is the F portion facing each other with the flat frame portion separated.

Similarly, the portion of the frame portion 15a sandwiched between the opposing E portions of the vertically adjacent protrusions 14 ', that is, the intersection portion of the frame portion 15 b' sandwiched between the opposing C portions of the laterally adjacent protrusions 14, is the F portion facing each other with the flat frame portions separated.

Since the portion F is separated from the frame portion when the blank B is strongly pressed, the portion F is not strongly pressed, and the blank B can be freely deformed.

As described above, since the blank B is embossed from both the front and back sides, the concave portions and the convex portions on the front and back surfaces of the blank B are embossed while being shifted by half a pitch in the vertical and horizontal directions.

In this case, conventionally, the entire surface of the material B is sandwiched by the surfaces, and therefore, there is no space for paper to escape, but in the present embodiment, the stampers K1 and K2 are not all sandwiched by the surfaces, but there are portions sandwiched by the threads, and therefore, since there are portions that can be freely deformed in the material B when strongly pressed by the embossing, and these portions are pulled and deformed on the load application side in the molding of the convex portions and concave portions, it is possible to form the embossing processing in which the convex portions are as dense as possible without causing cracks or damages to the material B while ensuring the difference in height between the concave portions and convex portions.

That is, the material can move freely in the axial direction at both ends of the portion sandwiched by the surfaces (lines). (see FIGS. 11(a) and (d)).

At the same time, the dies K1 and K2 press the portions (the blank is freely moved) which were not pressed in the previous stage, by the rotation of the embossing rollers R1 and R2, next to the portion which is pressed and sandwiched by the pair of dies K1 and K2.

That is, as shown in fig. 11(d), the freely movable portions at both ends of the held portion are formed as the next held portion by the rotation of the roller.

In this way, the distribution of the portions pressed by the stampers K1 and K2 and the portions not pressed is uniform in the axial direction.

For the above reasons, even if the blank is embossed, wrinkles are less likely to be formed and the blank is less likely to be broken.

In the present embodiment, as described above, the lateral width of the projection portions 14, 14 ' and the

frame portions

15a, 15a ' is narrowed and the height of the projection portions 14, 14 ' is set to be low in the portion that is to be the lower portion when the blank paper cup is attached.

Fig. 9(a) and (b) show an example of the shape of the projections 14 and 14' in such a case.

The protrusions 14 and 14 'have side wall surfaces 12 and 12' inclined from the four sides of the cell c toward the center, respectively, and one pair of opposing side wall surfaces gather at the upper end thereof to form linear top portions 13 and 13 ', and the other pair of opposing side wall surfaces are formed into a four-sided top shape (the hallow せ toot shape) in which the upper ends thereof gather at the respective end portions of the top portions 13 and 13'.

In this embodiment, since the blank B has a fan shape, the projections 14 and 14' (cells c) of the upper and lower dies K1 and K2 gradually narrow from the arc side of the upper end of the width of the blank B to the arc side of the lower end of the width, i.e., from the top to the bottom of the body of the cup.

For convenience of explanation, the rows of the cells c are referred to as row 1, row 2, and row 3 … in order from top to bottom in the column direction, and the cells in each row of the cells c have the same width, but the width of the cells c in the lower row (for example, the cells in row 2) is relatively equal to or less than the width of the cells c in the upper row (for example, the cells in row 1).

Further, since the die K1 serving as the upper die and the die K2 serving as the lower die are vertically shifted by half pitch in the lateral width of each cell c and the die K2 of the upper die contacts the material B with a delay with respect to the die K2 of the lower die, the lateral width of the cell c in row 1 of the die K2 of the lower die is equal to or larger than the lateral width of the cell c in row 1 of the die K1 of the upper die and the lateral width of the cell c in row 2 of the die K2 of the lower die, and this relationship is repeated in this order.

The width of the cells c may be changed every upper and lower rows or every plurality of rows.

The top portions 13 and 13 ' of the protrusions 14 and 14 ' are linear, and the top portions 13 and 13 ' are respectively included in the lateral width of the

frame portions

15a and 15a ' during pressing, and the top portions 13 and 13 ' are arranged so as to include main portions on the surfaces of the intersecting

portions

15c and 15c of the frame portions.

Fig. 10 shows a case where the stamps K1 and K2 are arranged with a half pitch offset, and the combinations of the stamps are shown by hatching from the parts a to F in fig. 8 (b).

Other structures are the same as those of the above embodiment, and therefore, the description thereof is omitted.

As for the protrusions 14 and 14 ' and the vertical and

horizontal frame portions

15a, 15B, 15a ', and 15B ' formed in a lattice shape, similarly to fig. 8, since the one die K1 and the other die K2 are arranged with a half pitch offset in the vertical and horizontal directions, the convex portion 4 and the concave portion 5 (see fig. 8) can be formed below the blank B in accordance with the above-described structure.

Thereby, the following are formed on the surface of the blank B: a quadrangular frame portion 6 partitioning quadrangular cells c surrounded by a lattice frame extending in the vertical and horizontal directions at regular intervals and intersecting therewith; and a convex portion 4, the convex portion 4 having a side wall surface 4a and a top portion 4B, the side wall surface 4a bulging from the surface of the blank B toward one side from four directions of each side of the cell c surrounded by the frame portion 6 toward the center side of the cell c, the top portion 4B being formed in a line shape or a surface gathered at the tip of the side wall surface 4 a.

On the other hand, on the back surface of the blank B, there are formed: a frame portion 6 'which partitions each of the small rectangular cells c surrounded by a lattice frame which extends in the longitudinal and transverse directions at the same regular intervals as the surface of the blank B and intersects with the surface of the blank B, and which is formed by shifting the frame portion 6' on the surface by half pitch in the longitudinal and transverse directions of the frame portion 6; and a recessed portion 5 seen from the surface of the blank B, the recessed portion 5 having a side wall surface 5a 'and a recessed portion 5B', the side wall surface 5a 'rising from the back surface of the blank to the other side from the center side of the cell from the four directions of the sides of the cell, the recessed portion 5B' being formed in a plane or a line shape converging at the tip of the side wall surface 5a ', the recessed portion 5 being formed in the longitudinal direction and the lateral direction of the protruding portion 4 of the surface with a half pitch offset, and an inclined surface having at least four corners matching the side wall surface 4a of the protruding portion 4 and the side wall surface 5 a' of the recessed portion 5 being formed on the back surface of the blank B.

The concave portion 5 is a concave portion when viewed from the front surface of the blank B, but is a convex portion when viewed from the back surface.

Further, since the intersection portions of the central portions of the side wall surfaces 4a and 5a 'of the convex portion 4 and the concave portion 5 and the frame portions 6 and 6' at regular intervals are not directly pressed strongly, the billet can be freely pulled even at the portions to which the load is applied by the press molding, and the press molding can be performed without cracking or damaging the billet B.

In the above embodiment, the case where the blank B has a fan shape was described as an example, but the blank B may have a square shape, a rectangular shape, or any other arbitrary shape.

Although the embossing process is performed on the entire surface of the web B, the embossing process may be performed on a part of the web B.

In short, it is needless to say that various design changes can be made without changing the spirit of the invention.

Description of the reference numerals

1: a paper cup; 2: an inner cup; 3: an outer sleeve; 4: a convex portion; 5: a recess; 6: a frame (lattice-shaped frame); 12. 12': a side wall surface; 13. 13': a top portion; 14. 14': a protrusion portion; 15a, 15 a': a longitudinal frame portion; 15b, 15 b': a transverse frame portion; 15c, 15 c': a crossover site; c: a small grid; c1, c 2: two adjacent edges of the cell; c 3: a point of intersection; k1, K2: pressing the die; r1, R2: an embossing roll.

Claims

1. A method of manufacturing a paper cup by embossing a blank of a trunk portion of the paper cup or an outer sleeve wound around the outer periphery of the trunk portion with a pair of opposed embossing rollers,

embossing the blank with concave-convex patterns,

the top of each protrusion of the pair of dies faces each other in a state of being close to a predetermined intersection portion of the frame portion at the center of four protrusions vertically and horizontally adjacent to each other in the opposite dies,

2. The method of manufacturing a paper cup according to claim 1,

the top portions of the protrusions of the pair of dies are set to a width within the lateral width of the frame portion where the opposing dies face the top portions.

3. The method of manufacturing a paper cup according to claim 1 or 2,

a pair of dies is set to: the lateral width of the vertical frame of the die that is opposed to the die and is then brought into contact with the blank is shorter than the lateral width of the protrusion.

4. A device for manufacturing a paper cup, which forms an embossing on a body of the paper cup or a blank of an outer sleeve wound around the outer periphery of the body by a pair of opposed embossing rollers,

embossing the blank with concave-convex patterns,

5. A manufacturing device of a paper cup is characterized in that,

a method of manufacturing a paper cup according to any one of claims 1 to 3.

6. A paper cup, which is characterized in that embossing is formed on a body of the paper cup or a blank of an outer sleeve wound around the outer periphery of the body by a pair of opposed embossing rollers,

the back surface of the blank is provided with: a frame portion that partitions each of quadrilateral cells surrounded by a lattice frame, the lattice frame extending in a longitudinal direction and a transverse direction at regular intervals equal to a surface of the blank and intersecting the lattice frame, the frame portion being formed in the longitudinal direction and the transverse direction of the frame portion on the surface with a half pitch offset; and a recessed portion which is formed by a side wall surface extending from four sides of each side of the cell toward a center side of the cell and protruding from a back surface of the blank toward the other side, and a surface or a linear bottom portion formed to be integrated with a front end of the side wall surface, and which is formed by being shifted by a half pitch in a longitudinal direction and a lateral direction of the protruding portion on the front surface, and which includes an inclined surface in which at least four corners of the side wall surface of the protruding portion and the side wall surface of the recessed portion coincide with each other on the back surface of the blank,

the tops of the protrusions of the pair of dies formed on the surfaces of the pair of embossing rollers respectively face each other in a state close to a predetermined intersection portion of the frame portion at the center of the four protrusions vertically and horizontally adjacent to each other,

7. A paper cup is characterized in that a paper cup is provided,

a paper cup produced by the method according to any one of claims 1 to 3.