JP3377284B2 - Mandrel for holding the inner surface of the can - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to the case of painting or printing on the outer surface of a bottomed cylindrical can body or the like in which a can bottom and a can body having a ring-shaped projecting portion at the tip are integrally molded. The present invention relates to a mandrel for holding a can body from the inner surface side of the can.

[0002]

2. Description of the Related Art A bottomed cylindrical can body in which a can body and a can bottom are integrally formed, for example, a squeezed iron can for beverages (two-piece can)
Is generally manufactured on a line that is consistent from molding to product finishing, and painting and printing are incorporated in the line. The molded steel can or aluminum can is washed and surface-treated, and then painted and printed.

Regarding general painting and printing mechanisms,
A continuous printing method is used in which a mandrel wheel having a large number of mandrels continuously rotates, and the mandrel takes a locus along an arc of a blanket for painting and printing.

When painting and printing on the can body surface of such a can, a mandrel 101 as shown in FIG. 8 is usually used. This mandrel 101 passes through the center of the mandrel 101 to draw and pull the can 102 into and out of the mandrel 101, and a central passage 103 controllably connected to a source of pressurized air or vacuum (not shown).
And a sleeve 10 rotatably supported by bearings 105 and 106 about the central shaft 104.
It is basically composed of 7.

On the other hand, in the can manufacturing industry, in order to reduce the can manufacturing cost, the wall thickness has been reduced and the can bottom shape has been changed accordingly. That is, if the wall thickness is reduced, the pressure resistance of the bottom of the can against drop impacts, etc. will decrease, so the diameter of the bottom of the can will be reduced, and the annular projection will protrude outward between the center dome and the bottom of the can. The strength of is increasing.

Therefore, in a mandrel for holding such a thin can, a tip end of a cylindrical sleeve whose outer diameter is smaller than the inner diameter of the can by about 0.5 mm usually has a curvature shape smaller than that of the annular protrusion of the can bottom. None, it has a tip portion that contacts the inner bottom surface of the annular protrusion and positions the can.

In addition to the positioning function of the can, this tip portion also has the function of sealing the vacuum force for holding the can at the correct position on the mandrel, and is formed integrally with the sleeve.

When coating or printing on the outer surface of the can body using the mandrel structure, the mandrel generally changes the can body peripheral speed to the blanket peripheral speed by a rotating means such as a spin belt before the coating or printing. The can is preliminarily rotated through the mandrel at a high speed of 2000 rpm or more in order to adjust to the speed of the can. A slight slip occurs between the bottom and the tip of the sleeve 107. That is, since the can and the mandrel are provided with a clearance required for insertion, as shown in FIGS. 9 and 10, when the printing pressure of the blanket 108 is applied, the blanket and the mandrel are subject to the printing pressure. Since the can 102 is sandwiched between and, there is no clearance, and the clearance is offset to the point B on the opposite side. Therefore, the rotation center O ₁ of the mandrel 101 and the can axis O
_A misalignment p is generated in ₂ and a slip occurs due to the misalignment p. The occurrence of the misalignment p is unavoidable because it is necessary to provide a clearance between the can and the mandrel.

When such a slip occurs, a vacuum force acts on the tip portion of the sleeve 107 to strongly hold the inner surface of the annular protrusion 109 and the contact pressure is high.
Also, since the tip of the sleeve is made of a hard material such as metal, when the can makes one revolution, a deep scratch 110 having a jagged shape with a short length as shown in FIG.
It is generated on the entire inner surface of 09. Incidentally, 111 is a reduced diameter portion of the can bottom. As a result, in the case of producing a can body used for applications such as carbonated beverages, etc. where the inner coating performance is lowered and the contents are adversely affected, or the inner coating performance is strictly required, the damaged chemical A large amount of internal paint was required to repair the treated film, resulting in high cost.

Therefore, for a can whose inner surface coating performance is strictly required, a mandrel having a sleeve fitted with a resin has been generally used, but since it is a resin, it is easily worn and the can is placed at an appropriate position. There is a problem in that the tip portion must be periodically replaced because it will not be retained and will result in defective painting and printing, which requires a lot of time and labor for maintenance.

A conventional mandrel mechanism for preventing such scratches and abrasions is, for example, Japanese Patent Publication No. 60-107.
The one described in Japanese Patent No. 88 is known.

[0012] The above-mentioned conventional publication discloses a mandrel mechanism for holding the can by holding the inner bottom surface of the center of the can bottom by suction and contact with a rotatable receiving member and holding the tip of the sleeve without contact with the peripheral edge of the can bottom. It is shown.

[0013]

However, in the mandrel mechanism described in the above-mentioned conventional publication, although it is presumed that the mandrel mechanism has a temporary prevention effect against scratches and abrasion on the peripheral edge of the can bottom, The bottom surface of the mandrel, which has the same axis of rotation as the central axis of the mandrel, holds the surface of the mandrel in a stable and stable manner. Since it does not easily occur at the bottom of the can, even if it occurs at the can wall, it is easy to cause distortion in the can body itself with a thin wall or to generate wrinkle-like wrinkles, which damages the appearance of the can and causes painting and printing. There is a risk of causing defects, and there is a problem that it is disadvantageous for painting and printing of thin cans.

The present invention has been made in view of the above problems, and it is possible to prevent both the occurrence of scratches on the periphery of the can bottom and the occurrence of wrinkles on the can body at the same time, and the sleeve tip is It is an object of the present invention to provide a mandrel for holding an inner surface of a can, which makes it possible to perform proper painting and printing by eliminating edge wear and which is advantageous for painting and printing a cylindrical can body with a bottom .

[0015]

In order to solve the above problems, in the invention according to claim 1, the can bottom holder is loosely fitted in an annular recess formed at the tip of the mandrel sleeve, and the can bottom holder is centered on the mandrel. It is configured to be movable in the direction orthogonal to the axis.

[0016] That is, co the can bottom periphery to tip and can bottom and a can body having an annular protrusion is positioned fitted with bottomed cylindrical can body which is integrally formed with reduced diameter, and rotatably holds
Then, apply the blanket printing pressure to the bottomed cylindrical can body and apply it.
In a mandrel used for mounting and printing, the mandrel comprises a substantially cylindrical sleeve having an outer diameter smaller than the can inner diameter, an annular recess is provided at the tip of the sleeve, and the annular projection is provided in the annular recess. A can bottom holder contacting the inner surface of the can is loosely fitted so as to be movable in a direction orthogonal to the central axis of the mandrel, and the can inner surface is held by the cylindrical sleeve outer peripheral portion and the can bottom holder. Is characterized by.

According to the second aspect of the invention, the can bottom holder is supported by an elastic body provided between the inner peripheral wall of the can bottom holder and the inner diameter wall of the annular recess, and the mandrel is It is rotatably supported at least in the forward direction with respect to the rotation direction.

Further, in the invention according to claim 3, the can bottom holder is supported by an elastic body provided between an outer peripheral wall of the can bottom holder and an outer diameter wall of the annular recess, and the mandrel. It is rotatably supported at least in the forward direction with respect to the rotation direction of.

Further, in the invention according to claim 4, the elastic body is composed of at least three or more leaf springs.

Further, the radial gap between the can bottom holder and the outer diameter wall of the annular recess is defined to be 1/2 or more of the difference between the inner diameter of the can and the outer diameter of the sleeve.

[0021]

According to the first aspect of the invention, the can is held by the mandrel, and at this time, in the can bottom, only the annular projection of the can bottom and the tip portion of the can bottom holder are in contact with each other. ,
There is no contact at the reduced diameter portion and the peripheral edge of the can bottom. Then, the printing pressure of the blanket is received, and the clearance between the can and the mandrel is moved to the side opposite to the portion receiving the printing pressure, and the ink on the blanket is displaced while causing the misalignment between the rotation center of the mandrel and the can axis. When transferred to the outer surface of the can body, the can bottom holder moves integrally with the can bottom in a direction orthogonal to the central axis of the mandrel, independently of the movement of the sleeve, and is automatically centered around the can axis. No radial slip occurs on the contact surface between the tip portion of the holder and the annular protrusion.

According to a second aspect of the present invention, the can bottom holder is supported by an elastic body provided between an inner peripheral wall of the can bottom holder and an inner diameter wall of the annular recess, and the mandrel is rotated in the rotating direction. Since it is rotatably supported at least in the forward direction with respect to the can, even when the mandrel is delayed with respect to the can and slips when the torque is transmitted from the blanket to the mandrel through the can barrel during transfer, The bottom holder can move integrally with the bottom of the can.

In the invention of claim 3, the can bottom holder is supported by an elastic body provided between the outer peripheral wall of the can bottom holder and the outer diameter wall of the annular recess, and the mandrel is rotated. Since it is rotatably supported at least in the forward direction with respect to the direction, the same effect as that of the invention according to claim 2 can be obtained.

According to a fourth aspect of the present invention, the elastic body is
Since it is composed of at least three leaf springs, it is only necessary to change the thickness of the leaf spring when adjusting the cushion state of the can bottom holder to make it stronger or weaker.

According to the fifth aspect of the present invention, the radial gap between the can bottom holder and the outer diameter wall of the annular recess is at least half the difference between the can inner diameter and the sleeve outer diameter. Therefore, the movement of the can bottom holder in the direction orthogonal to the central axis of the mandrel can be ensured.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

First, the structure will be described.

FIG. 1 is a schematic view showing the mechanism of a dry offset type high speed curved surface printing press 1. A is a can feed, B is a star wheel, C is a mandrel wheel, and D.
Is a blanket, E is a press pin zone, F is a printing zone, G is an overburnish zone, H is a transfer unit, and I is an oven chain.

The general flow of the can 2 in the printing machine 1 will be described. First, the can 2 is supplied from the can feed A to the star wheel B, and the mandrels 3 arranged around the mandrel wheel C are attracted to each other by suction force. And is positioned and held by the mandrel 3. Then, can 2
Is transported to the press pin zone E by the rotation of the mandrel wheel C, is given a high-speed preliminary rotation by the spin belt 4, and is transported to the printing zone F at a speed substantially the same as the peripheral speed of the blanket D.

In the printing zone F, the printing pressure of the blanket D is applied to the outer surface of the can body to transfer the ink on the blanket D, and then the can 2 is placed in the overburnish zone G.
Finish varnish is wet coated. Printed cans 2
Is transported to the transfer unit H, and is supported by an oven chain I having a pin called a pin chain one by one and heated and dried in an oven (not shown).

FIG. 2 is a sectional view of the mandrel 3 arranged around the mandrel wheel C, and FIG.
FIG. 4 is a cross-sectional view taken along a line, and the structure of the mandrel 3 will be described in detail with reference to FIGS. 2 and 3.

Reference numeral 5 denotes a central axis of the mandrel 3. The central axis 5 of the mandrel passes through the central axis 5 of the mandrel in order to draw the can 2 into or out of the mandrel 3, so that a pressure air source or a vacuum is supplied. It has a central passage 6 which is controllably connected to a source (not shown).

A sleeve 7 is rotatably supported by bearings 8 and 9 about its central axis. The sleeve 7 is a substantially cylindrical outer sleeve member having a diameter slightly smaller than the inner diameter of the can. 7a and a sleeve inner member 7b that supports a can bottom holder described later. The sleeve inner member 7b is screwed in so that the tip thereof is substantially level with the tip of the sleeve outer member 7a, and both members 7a, 7a,
The annular recess 11 is formed with 7b.

Reference numeral 10 has a tip shape having a curvature smaller than that of the annular protruding portion 2a of the can bottom, and the annular concave portion 11 is protruded outward from the annular concave portion 11 of the sleeve.
It is an iron nose body (can bottom holder) loosely fitted inside.
This nose body 10 is evenly provided from the inside by an elastic body (in this example, a leaf spring having a plate thickness of 0.3 mm) 12 attached to the sleeve inner member 7b at 90-degree intervals in the annular recess 11, and the nose body 10 has a uniform shape. It is floatingly supported in a floating state so as not to contact the inner peripheral wall and the outer peripheral wall. Further, a gap is provided between the outer peripheral wall 14 of the nose body 10 and the inner peripheral wall 15 of the sleeve outer member 7a (corresponding to the outer diameter wall of the annular recess 11), and the nose body 10 is connected to the central axis 5 of the mandrel. It is configured to be freely movable in the orthogonal direction.

Therefore, by providing the above-mentioned structure, even if the center misalignment p of the mandrel rotation center 0 ₁ and the can axis center 0 ₂ occurs when the printing pressure of the blanket D is applied at the time of coating and printing, the nose is generated. The body 10 freely moves integrally with the can bottom in a direction orthogonal to the central axis 5 of the mandrel. That is, the nose body 10 is provided with the self-aligning action that does not cause the center deviation from the center of the can axis.

The radial gap between the outer peripheral wall 14 of the nose body 10 and the inner peripheral wall 15 of the sleeve outer member 7a is slightly larger than half the difference between the inner diameter of the can and the outer peripheral diameter of the sleeve (in this example, the clearance). It is configured to be 0.1 mm larger) and has a margin in the moving range of the nose body 10.

Further, the leaf spring 12 is attached to the outer peripheral wall 16 of the sleeve inner member 7b (corresponding to the inner diameter wall of the annular recess 11), and the nose body 10 is rotated in the rotating direction of the mandrel 3 (clockwise in FIG. 3). It is attached in one direction so as to be rotatable in the forward direction (the same direction) with respect to the (direction).

Because the mandrel is transmitted and rotated from the blanket through the can body from the time of contact with the blanket, the mandrel itself receives physical resistance such as weight and bearings, but the can is slightly. It will be delayed than. Therefore, in order to prevent the nose body 10 from becoming a slip together with the can bottom, the nose body 1
It must be possible to rotate 0 in the forward direction with respect to the direction of rotation of the mandrel.

On the other hand, a retaining ring 13 is attached to the outer peripheral wall 16 of the sleeve inner member 7b so as to prevent the nose body 10 from falling out of the annular recess 11, and is engaged with the hanging portion 10a of the nose body 10. is there. In addition, this snap ring 13
The sliding surface is surface-finished so that the nose body 10 can rotate smoothly, and the nose body 10 is attached with a minute gap so that the nose body 10 can be slightly moved back and forth in the axial direction. Therefore, the positioning of the can is performed by bringing the nose body 10 in contact with the annular protruding portion 2a of the can bottom into contact with the bottom surface 11a of the annular recess 11.

Further, the peripheral shape of the nose body 10 is such that the reduced diameter portion 2b of the can bottom extends from the tip to the tip of the sleeve outer member 7a.
The inclined surface is configured so that it does not come into contact with the mandrel, facilitating the insertion and insertion of the can into the mandrel, and deformation or damage of the open end of the can that tends to occur during the insertion operation, and eventually defective printing due to poor holding of the can Is configured to prevent.

Next, the operation will be described.

The can 2 is held on the mandrel 3 by the vacuum force via the central passage 6 of the mandrel central axis 5. In the can bottom, only the annular protrusion 2a of the can bottom and the tip portion of the nose body 10 are in contact with each other, and there is no contact in the reduced diameter portion 2b of the can bottom and the peripheral edge.

In this state, the sheet is conveyed to the press pin zone E. Here, the mandrel 3 is preliminarily rotated by the spin belt 4 so that the speed becomes the same as the printing speed, and the can 2
The sleeve 7 and the nose body 10 are integrally rotated at high speed and conveyed to the printing zone F.

In the printing zone F, the printing pressure of the blanket D is received, and the clearance between the can 2 and the mandrel 3 is moved to the side opposite to the portion receiving the printing pressure, and the center of rotation of the mandrel 3 and the center of the can shaft are centered. The ink on the blanket D is transferred to the outer surface of the can body while rotating while causing a displacement. At this time, the nose body 10 moves integrally with the can bottom in a direction orthogonal to the mandrel center axis 5 and is automatically centered around the center of the can axis, and the nose body 10 is not affected by the rotation of the sleeve 7. Since it rotates integrally with the bottom, no slip occurs at the contact surface between the tip of the nose body 10 and the annular protrusion 2a.

As described above, in the mandrel 3 for holding the inner surface of the can of the embodiment, the following effects can be obtained.

The nose body 10, which is a can bottom holder, is loosely fitted in the annular recess 11 formed at the tip of the mandrel sleeve 7, and the nose body 10 is movable in the direction orthogonal to the mandrel central axis 5. Even if there is a center misalignment between the center of rotation of the can and the center of the can axis, the annular protruding portion of the can bottom is moved by the self-aligning action of the nose body 10 that moves integrally with the can bottom to align the center with the center of the can axis. No slip occurs on the contact surface between the 2a and the nose body 10. As a result, it is possible to prevent the annular protrusion 2a of the can bottom from being scratched due to misalignment.

Since the stress caused by the misalignment between the can 2 and the mandrel 3 is released by the self-centering action of the nose body 10, twisting wrinkles do not occur in the thin portion of the can body and the appearance of the can is impaired. Without being advantageous to the outer surface painting and printing of thin cans.

Since slip does not occur on the contact surface between the annular protrusion 2a and the nose body 10, it can be used for the production of can bodies used for applications such as carbonated drinks, etc., where the performance of the inner coating film is strictly required. It is possible to use a mandrel in which the nose body 10 is made of metal, and wear of the tip can be eliminated. As a result, the problem of paint printing defects disappears,
Moreover, the maintenance of the mandrel becomes very simple.

Since the nose body 10 can rotate in the same forward direction as the rotation direction of the mandrel, when it comes into rotational contact with the blanket D, a slip occurs between the can 2 and the mandrel 3 due to the physical action of the mandrel. Nose body 10
Since the can and the bottom can move together, the nose body 10
It is possible to more reliably prevent scratches caused by.

A leaf spring 1 in which the nose body 10 is provided between the inner peripheral wall of the nose body 10 and the outer peripheral wall 16 of the sleeve inner member 7b.
Since it is elastically supported by 2, it is not necessary to attach a leaf spring to the nose body 10, the structure is simple, it is possible to prevent the movement balance from being disturbed, and even if the can bottom shape is different,
There is an advantage that only the nose body can be replaced without changing the leaf spring.

Since the nose body 10 is floatingly supported by the four leaf springs attached to the sleeve inner member 7b, when adjusting the cushion state of the nose body 10 to make it stronger or weaker, the thickness of the leaf spring is adjusted. It only needs to be changed, it is economical and very easy to adjust and modify.

The radial gap between the outer peripheral wall 14 of the nose body 10 and the inner peripheral wall 15 of the outer sleeve member 7a is equal to or slightly larger than half the difference between the inner diameter of the can and the outer peripheral diameter of the sleeve. Therefore, it is possible to reduce the wobbling of the nose body 10, eliminate the loading error of the can, and ensure both the can bottom holding action and the self-centering action.

[Experimental Example] Using the mandrel for holding the inner surface of the can of the present example, a thin two-piece can was printed on the outer surface under the following conditions, and then the inner surface was repair-painted to manufacture.

Can type; 350 ml aluminum can Can inner diameter; 65.9 mm Minimum wall thickness of can barrel; 0.102 mm Mandrel and nose body material; Iron (SUJ2) mandrel sleeve outer diameter; 65.3 mm Can inner diameter and mandrel sleeve The difference from the outer diameter: 0.6 mm After that, 20 cans were extracted from the cans whose inner surface had been repair-painted, and the leakage current value of these cans when a current of 6% for 3 seconds was applied with a 1% solution of Nacl was measured. Also, as a comparative example,
The leakage current value was measured in the same manner as in the present example except that the nose body was integrated with the sleeve.

As shown in Table 1 below, in the examples of the present invention, Q
The TV value can be set to zero and the performance of the inner coating film can be greatly improved. It can be used for the production of cans for carbonated beverages, etc. that could not be applied even if the coating amount was increased in the comparative example. Became.

Also, in the investigation of the scratches on the annular protrusion of the can bottom, the jagged deep scratches (see FIG. 11) seen in the comparative example were not found at all. Also, no wrinkles were observed on the thin wall of the can body.

[0057]

[Table 1]

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, the sleeve 7 is composed of the outer member 7a and the inner member 7b. However, the positions of the bearings 8 and 9 may be changed to be integrally formed.

Although four leaf springs are used in the embodiment,
The number of leaf springs should be at least three or more.

In the embodiment, the nose body 10 is elastically supported by the leaf spring 12 provided between the inner peripheral wall of the nose body and the outer peripheral wall 16 of the sleeve inner member. The leaf spring 12 is shown in FIGS. As shown in, it may be provided between the outer peripheral wall 14 of the nose body 10 and the inner peripheral wall 15 of the sleeve outer member 7a. In this case, in order to allow the nose body to rotate in the forward direction with respect to the rotation direction of the mandrel, the mounting direction of the leaf spring 12 must be reversed from that shown in FIG.

In the embodiment, the nose body is supported by the leaf spring. However, as shown in FIG. 6, the nose body is an elastic body in which a cylindrical rubber 20 such as a Teflon tube or a urethane tube is held by a retainer 21, or As shown in FIG. 7, it may be supported by a wire 30, and even if the mandrel may be delayed during transfer, the same effect as that of this embodiment can be obtained if only the nose body can rotate together with the can bottom. it can.

In the embodiment, the nose body is made of iron, but it is sufficient if it is made of a hard material and slip wear during transfer does not occur. Therefore, for example, an engineering plastic such as a polyimide hard polymer is fitted to the tip of the nose body. It is also possible to use a hard material such as a ceramic or the like in which the surface of the nose is less likely to be roughened by the edge of the open end of the can when the can is loaded.

[0064]

As described above, according to the present invention, the following effects can be obtained.

(1) In the mandrel for holding the inner surface of a can according to claim 1, the can bottom holder is loosely fitted in an annular recess formed at the tip of the mandrel sleeve, and the can bottom holder serves as the mandrel central axis. Since it is configured to move in the orthogonal direction,
Even if misalignment occurs between the center of rotation of the mandrel and the center of the can axis, the can bottom holder shifts integrally with the can bottom by the self-centering action of the can bottom holder. The slip on the contact surface does not occur, and the annular protrusion on the bottom of the can can be completely prevented from being scratched due to misalignment, and the thin-walled portion of the can body does not have twisted wrinkles. It is advantageous for the outer surface coating and printing of the bottomed cylindrical can body without impairing the appearance of the above.

Also, in the production of a can body used for applications such as carbonated drinks, etc., where the performance of the inner surface coating film is strictly required, it is possible to use a mandrel having a metal can bottom holder,
Since the tip wear can be eliminated altogether, the problem of defective painting and printing can be eliminated, and the maintenance of the mandrel becomes very simple.

(2) In the mandrel for holding the inner surface of a can according to claim 2, in addition to the effect of the above (1), the can bottom holder has an inner peripheral wall of the can bottom holder and an inner diameter of the annular recess. Since the mandrel is supported by an elastic body provided between the mandrel and the wall and is rotatably supported in at least the forward direction with respect to the rotating direction of the mandrel, the mandrel tends to be behind the can during transfer. Even in this case, since the can bottom holder and the can bottom can move as a unit, it is possible to reliably prevent abrasion due to the can bottom holder.

(3) In the can inner surface holding mandrel according to claim 3, in addition to the effect of the above (1), the can bottom holder is provided outside the outer wall of the can bottom holder and the annular recess. Since it is supported by the elastic body provided between the radial wall and the mandrel and is rotatably supported at least in the forward direction with respect to the rotating direction of the mandrel, the same effect as the above (2) can be obtained.

(4) In the can inner surface holder mandrel according to claim 4, since the elastic body is composed of at least three leaf springs, the can bottom holder is made to have a strong cushioning state. When adjusting or weakening or adjusting, it is only necessary to change the plate thickness of the leaf spring, which is economical and extremely easy to adjust and correct.

(5) In the mandrel for holding the inner surface of a can according to claim 5, the gap between the can bottom holder and the outer diameter wall of the annular recess is 1 / the difference between the inner diameter of the can and the outer diameter of the sleeve. Since it is composed of two or more, the can bottom holder can be surely moved in the direction orthogonal to the central axis of the mandrel.

[Brief description of drawings]

FIG. 1 is a schematic view of a high-speed curved surface printing machine targeted by the present invention.

FIG. 2 is a cross-sectional view showing a state in which a can is positioned and held by a mandrel according to an embodiment of the present invention.

3 is a cross-sectional view taken along the line I-I of FIG.

FIG. 4 is a modification of the embodiment of the present invention.

5 is a cross-sectional arrow view taken along the line II-II of FIG.

FIG. 6 is another modification of the embodiment of the present invention.

FIG. 7 is another modification of the embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a state in which a can is positioned and held by a conventional mandrel.

FIG. 9 is a state explanatory diagram of a mandrel and a can before transfer.

FIG. 10 is an explanatory diagram showing a state in which the mandrel is moved to one side during transfer.

FIG. 11 is a partially enlarged view showing a scratch generated on the inner surface of the can bottom of the conventional example.

[Explanation of symbols]

1 Dry offset type high-speed curved surface printing machine 2 cans 3 Mandrel 4 spin belts 5 Mandrel central axis 6 central passage 7 sleeve 8,9 bearing 10 Nose body (can bottom holder) 11 annular recess 12 leaf spring 13 retaining ring 14 Nose body outer wall 15 Inner peripheral wall of sleeve outer member (outer diameter wall of annular recess) 16 Outer peripheral wall of sleeve inner member (inner wall of annular recess) 20 Cylindrical rubber 21 cage 30 wire

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B05C 13/02 B41F 17/22 B21D 51/26 B23B 31/40

Claims (5)

(57) [Claims] 1. A bottomed cylindrical can body integrally formed with a can bottom and a can body having a can bottom peripheral edge reduced in diameter and having an annular protruding portion at its tip is inserted, positioned, and rotatably held . Bu
Applying the blanket printing pressure to the bottomed cylindrical can body for coating and
In a mandrel used for printing, the mandrel comprises a substantially cylindrical sleeve having an outer diameter smaller than the inner diameter of the can, an annular recess is provided at the tip of the sleeve, and the annular recess has an inner surface of the annular protrusion. A can bottom holder that abuts against is loosely fitted so as to be movable in a direction orthogonal to the central axis of the mandrel, and the can inner surface is held by the cylindrical sleeve outer peripheral portion and the can bottom holder. A mandrel for holding the inner surface of a can. 2. The can bottom holder is supported by an elastic body provided between an inner peripheral wall of the can bottom holder and an inner diameter wall of the annular recess, and at least forward with respect to the rotating direction of the mandrel. The mandrel for holding an inner surface of a can according to claim 1, which is rotatably supported by the mandrel. 3. The can bottom holder is supported by an elastic body provided between an outer peripheral wall of the can bottom holder and an outer diameter wall of the annular recess, and is at least forward with respect to the rotating direction of the mandrel. The mandrel for holding an inner surface of a can according to claim 1, which is rotatably supported in a direction. 4. The mandrel for holding an inner surface of a can according to claim 2, wherein the elastic body is composed of at least three leaf springs. 5. The radial gap between the can bottom holder and the outer diameter wall of the annular recess is at least ½ of the difference between the inner diameter of the can and the outer diameter of the sleeve. The mandrel for holding the inner surface of a can according to any one of 1.