JPH11198334A - Engraving head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engraving head for a gravure engraving system for damping an excess vibration of a diamond cutting tool with good durability without depending upon an ambient temperature and further rapidly vibrating the tool. SOLUTION: When a shaft 103 is vibrated, a conductive plate 11 fixed to the shaft 103 is vibrated in a direction of an arrow (d), and the plate 11 crosses a magnetic flux changing in a short side direction of a length L1. Accordingly, a Lorentz force of a reverse force to a moving direction of the plate 11 is generated in the plate 11. A magnitude of the force is proportional to a moving speed of a diamond cutting tool 101. Therefore, the tool 101 relatively rapidly moves due to its transient response at a part in which a stepwise density signal abruptly changes to tend to overshoot, but a magnetic damper rapidly attenuates the overshoot of the tool 101 with the force as an attenuating force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engraving head, and more particularly, to an engraving head used in a gravure engraving system for producing an intaglio plate for gravure printing and engraving cells on the surface of a gravure cylinder.

[0002]

2. Description of the Related Art In a gravure engraving system, while rotating a cylindrical gravure cylinder with a copper plating on the surface, a small concave portion called a cell is engraved on the surface,
This is a system to create intaglio for gravure printing. In this gravure printing, the density of the printed matter is expressed by the amount of ink filled in the cells. Therefore, the gravure engraving system performs engraving while controlling the cell volume (ie, cell depth and width) using an engraving head.

FIG. 10 is a perspective view showing the configuration of an engraving head in a conventional gravure engraving system. In FIG. 10, the engraving head includes a diamond cutting tool 101,
Stylus 102, shaft 103, fixing portion 104
, A rotor 105 having a diamond shape in a plan view, a yoke 106 of a laminated magnetic material, a permanent magnet 107, and a coil 108.

A diamond cutting tool 101 has a triangular pyramid shape, and is attached to one end of a stylus 102. The diamond cutting tool 101 is mounted so as to be located near the surface of a gravure cylinder (not shown). The stylus 102 is fixed to one end of a shaft 103. Further, the other end of the shaft 103 is fixed to the fixing portion 104. Further, a rotor 105 is fixed to an intermediate portion of the shaft 103. Rotor 10
A yoke 106 is disposed around the rotor 5 so as to sandwich the rotor 105. The yoke 106 is given a magnetic force by a permanent magnet 107 arranged on one side.
Further, around the rotor 105, the rotor 105
A coil 108 is arranged between the coil 108 and the yoke 106.

In this gravure engraving system, a high-frequency carry signal and a step-like density signal are generated.
This carry signal has a time waveform as shown in FIG. 11A, and the density signal is shown in FIG.
Has a time waveform as shown in FIG. Then, the engraving signal is generated by superimposing the carry signal on the density signal. Therefore, the engraving signal has a time waveform as shown by a solid line in FIG.

When the engraving signal is applied to the coil 108 (see FIG. 10), a driving force is generated by the action of the magnetic field generated by the permanent magnet 107, and the shaft 103 vibrates around its central axis. , And transmits the driving force to the stylus 102. In response to the vibration of the shaft 103, the stylus 102 and the diamond tool 10
1 oscillates around the central axis of the shaft 103 as indicated by the arrow A while following the time change of the engraving signal. The cell is engraved on the surface of a gravure cylinder arranged in the vicinity thereof by the displacement amount due to the vibration of the diamond cutting tool 101.

As is clear from the above description, the displacement of the diamond cutting tool 101 due to the vibration is indicated by the solid line in FIG. In FIG. 11C, when the surface of the gravure cylinder is represented by a two-dot chain line, the diamond cutting tool 101 engraves a cell as indicated by a dotted portion. More specifically, when the level of the density signal is low, the diamond cutting tool 101 does not engrave the cell because it vibrates at a position relatively far from the surface of the gravure cylinder. However, when the level of the density signal is high, the diamond cutting tool 101 sculpts the cell because it vibrates at a position relatively close to the surface of the gravure cylinder.

As described above, in the conventional engraving head, the volume of the cell to be engraved is controlled based on the level of the density signal. However, conventionally, it is known that the displacement amount of the diamond cutting tool 101 overshoots in a portion where the step-like density signal changes abruptly. Due to this overshoot, the diamond bite 101 cannot engrave a cell having a volume that exactly follows the density signal (see the leftmost cell shown in FIG. 11C), and the printed matter by gravure printing has: There is a problem that a portion where the density is not correctly expressed occurs. Therefore, conventionally, a damping mechanism has been added to the shaft 101 of the engraving head. FIG.
Reference numeral 2 denotes various damping mechanisms conventionally proposed, and more specifically, US Pat. No. 3,964,382.
1 shows a damping mechanism disclosed in the above-mentioned publication. This U.S. Patent discloses three broad types of damping mechanisms.

First, a damping mechanism shown in FIG. 12A is composed of a housing 121 and four plastic pieces 122.
And The housing 10 includes the shaft 10
A through hole having a diameter larger than the diameter of No. 3 is formed. The shaft 103 is inserted through the through-hole such that the central axis thereof coincides with the central axis of the through-hole. As a result, a certain gap is formed between the shaft 103 and the annular surface of the through hole. Four plastic pieces 122 having a predetermined shape are pushed into this gap. Therefore, when the shaft 103 vibrates as shown by the arrow A,
A frictional force is generated on the contact surface between the shaft 103 and each plastic piece 122. The vibration of the diamond cutting tool 101 is attenuated (damped) by the frictional force.

Next, the damping mechanism shown in FIG. 12B includes a housing 123 and an annular rubber ring 124. The housing 123 has a through hole having a diameter larger than the diameter of the shaft 103.
The shaft 103 is fastened with a rubber ring 124.
Then, the portion of the rubber ring 124 is
Into the through hole. Therefore, when the shaft 103 vibrates as indicated by the arrow A, the vibration of the diamond cutting tool 101 is attenuated (damped) by the internal friction (viscosity) of the rubber ring 124.

Next, the damping mechanism shown in FIG. 12C includes a disk 125 and a chamber 126. The disk 125 is fixed to the shaft 103. Chamber 1
26 is formed in a ring shape, and a space is formed therein. The chamber 126 receives the disk 125 by this space. Further, this space is filled with a viscous fluid L such as oil. In FIG. 12C, only a part of the chamber 126 is shown so that the internal structure thereof can be easily understood. Therefore, the shaft 10
When 3 vibrates as shown by the arrow A, the vibration of the diamond cutting tool 101 is attenuated (damped) by the viscosity of the viscous fluid L.

When each of the above damping mechanisms is added to a conventional engraving head, the diamond cutting tool 101 is damped by each damping mechanism in a portion where the density signal (see FIG. 11B) rises rapidly, and Can be engraved on the surface of the gravure cylinder (see the leftmost cell shown in FIG. 11 (d)).

[0013]

However, FIG.
The damping mechanism shown in FIG.
Is pressed against the shaft 103 to generate a frictional force, and the frictional force is used as a damping force to obtain a damping effect. When the damping mechanism repeatedly operates, the plastic piece 122 gradually wears, so that the damping force generated by the damping mechanism gradually decreases, and the damping effect is weakened. As a result, the diamond bite 101
However, there is a problem that a cell having a volume that accurately follows a density signal cannot be engraved. If the frictional force is excessively increased to increase the damping effect, the engraving head will not respond quickly to the engraving signal, that is, the rising characteristics will deteriorate.

The damping mechanism shown in FIG. 12 (b) obtains an effect of damping by the internal friction (viscosity) of the rubber ring 124. When the rubber ring 124 is used for a long time, it deteriorates due to aging, and the effect of damping is reduced. As a result, diamond tool 10
No. 1 has a problem that a cell having a volume that exactly follows the density signal cannot be engraved. In addition, the internal friction (viscosity) of rubber changes due to a change in ambient temperature. Therefore, the damping effect obtained by this damping mechanism largely depends on the ambient temperature. Therefore, even if the rubber ring 124 is not deteriorated, there is a problem that the diamond cutting tool 101 may not be able to engrave a cell having a volume that accurately follows the density signal depending on the ambient temperature.

The damping mechanism shown in FIG. 12 (c) obtains a damping effect due to the viscosity of the fluid inside the chamber 126. Fluid such as oil changes its viscosity due to a change in ambient temperature. Therefore, depending on the ambient temperature, there is a problem that the diamond cutting tool 101 may not be able to engrave a cell having a volume that accurately follows the density signal.

Meanwhile, in order to improve the processing speed of the gravure engraving system, it is required to vibrate the diamond cutting tool 101 at a higher speed. However, in each damping mechanism shown in FIG. 12, the damping rate (damping effect) differs according to the resonance frequency of the shaft 103 (frequency of the engraving signal). More specifically, FIG.
Each of the damping mechanisms shown in FIG.
When the frequency is 0 Hz or less, a relatively large attenuation rate can be obtained. However, when the resonance frequency becomes 4 KHz or more and becomes a frequency band often used in the gravure engraving system, the damping rate of each damping mechanism becomes relatively small. As a result, the diamond cutting tool 101 has a problem that it is not possible to engrave a cell having a volume that accurately follows the density signal in a portion where the density signal of the step changes rapidly.

Therefore, an object of the present invention is to dampen excessive vibration of the diamond cutting tool 101, to have good durability, to vibrate the diamond cutting tool 101 at high speed independent of the ambient temperature, and to vibrate the diamond cutting tool 101 at high speed. It is to provide an engraving head in a possible gravure engraving system.

[0018]

Means for Solving the Problems and Effects of the Invention The first invention is to manufacture an intaglio for gravure printing.
An engraving head for engraving cells on the surface of a gravure cylinder, a stylus having a needle-shaped cutting tool fixed to its tip, a shaft to which the stylus is fixed, and a stylus by vibrating the shaft by applying a driving force to the shaft. And a driving force applying unit for vibrating the cutting tool, and a magnetic damper for damping excessive vibration of the stylus, the magnetic damper is disposed in a non-contact manner with the conductor fixed to the shaft and the conductor, When the shaft oscillates, the conductor traverses the magnetic flux generated by the magnet portion, whereby the Lorentz force generated inside the conductor dampens excessive vibration of the stylus. It is characterized by the following.

According to the first aspect of the present invention, the Lorentz force generated inside the conductor is a force in the direction opposite to the vibration direction of the stylus, and is proportional to the speed of the movement. Therefore, the excessive vibration of the stylus can be damped. Here, since the conductor and the magnet unit are not in contact with each other and generate Lorentz force, unnecessary wear does not occur between the conductor and the magnet unit. As a result, the durability of the magnetic damper increases. Also, the magnetic damper generates a Lorentz force that is relatively independent of the ambient temperature of the engraving head, as compared to a conventional damping mechanism. As a result, the magnetic damper can always suitably dampen the excessive vibration of the stylus regardless of the temperature of the installation location of the gravure engraving system. Further, the conventional damping mechanism has a characteristic that the damping rate varies depending on the vibration frequency of the shaft. However, since the magnetic damper does not have such characteristics, even when the shaft, that is, the cutting tool is vibrated at a high speed, the excessive vibration of the stylus can be suitably damped.

According to a second aspect of the present invention, in the first aspect, the conductor has a plate-like shape, and the magnet portion has a pair of magnets. , One of the north poles and the other of the south poles are arranged so as to face each other with a conductor therebetween. According to the second invention,
The conductor can reliably cross the magnetic flux generated by the two magnets of the magnet section.

In a third aspect based on the first aspect, the conductor has a cylindrical shape with the shaft as a central axis, and the magnet portion has an N pole and an S pole along the outer periphery of the conductor. It is characterized by having magnets arranged alternately and annularly.
According to the third aspect, the outer periphery of the conductor can reliably cross the magnetic flux generated on the inner periphery of the annularly arranged magnet portion.

In a fourth aspect based on the first aspect, the conductor has a plate-like shape, and the N-pole and the S-pole are arranged in the magnet portion so as to face any one surface of the conductor. It is characterized by having a magnet that is provided. According to the fourth aspect, since the N pole and the S pole of the magnet face any one surface of the conductive plate, the conductor can cross the magnetic flux generated by the magnet. Thus, for example, there is no need to sandwich the conductor as in the second invention, and the magnet can be arranged without being relatively restricted by the arrangement space.

According to a fifth aspect, in the first to fourth aspects, the magnet portion further includes an electromagnet, and the damping force can be changed according to a voltage applied to the electromagnet. According to the fifth aspect, the magnet section includes the electromagnet. Therefore, by changing the voltage applied to the electromagnet, the magnetic force of the electromagnet can be changed. Thus, the present magnetic damper can generate a dynamic Lorentz force.

In a sixth aspect based on the first to fifth aspects, a magnetic fluid is filled between the conductor and the magnet portion.

According to the sixth aspect, the magnetic fluid is filled in the gap formed between the non-contact conductor and the magnet. Therefore, the magnetic resistance between the gaps is
The size is smaller than when the magnetic fluid is not filled.
Therefore, the magnetic damper can generate a larger Lorentz force, and a larger damping force can be obtained.

[0026]

FIG. 1 is a diagram for explaining a first embodiment of the present invention. In particular, FIG. 1A is a perspective view showing the engraving head according to the present embodiment. In particular, FIG. 1B is a diagram showing a configuration when the magnetic damper provided in the engraving head is viewed from the direction of arrow C shown in FIG. 1A. In FIG. 1A, the engraving head is shown in FIG.
Compared with the one shown in FIG. 0, the difference is that a magnetic damper is provided. Since there is no other difference, the corresponding components are denoted by the same reference numerals and the description thereof will be omitted.
Hereinafter, the magnetic damper will be described in detail. The magnetic damper includes a rectangular conductive plate (hereinafter, referred to as a conductive plate) 11 and four magnets 12 to 15 having the same rectangular parallelepiped shape.

The conductive plate 11 is typically made of aluminum, copper, or another conductive material, and is fixedly attached to the shaft 103. More specifically, the conductive plate 11
Is fixedly attached to a substantially intermediate portion between the stylus 102 and the rotor 105 such that the upper surface (and the lower surface) of the conductive plate 11 forms a plane perpendicular to the central axis of the shaft 103.

In the conductive plate 11 thus attached, two magnets 12 and 13 are fixedly arranged on one side of the shaft 103 as a center (FIG. 1).
Does not show a configuration for fixing the magnets 12 to 14 from the viewpoint of clarifying the illustration). Two magnets 12 and 1
Reference numeral 3 denotes a surface on the N pole side (the lower surface in the present embodiment) of the magnet 12 and a surface on the S pole side (in the present embodiment,
(Upper surface) so as to sandwich one side of the conductive plate 11 therebetween. However, the lower surface of the magnet 12 and the magnet 13
Are arranged at a predetermined distance so as not to contact the conductive plate 11 (see FIG. 1B).

Further, as shown in FIG.
1 has a short side having a length L1, and the magnets 12 and 13 have short sides having a length L2. In order to form a magnetic damper, it is preferable that the length L1 is designed to be longer than the length L2 and that both ends of the conductive plate 11 protrude from between the magnets 12 and 13. Thereby, the magnetic flux between the magnets 12 and 13 has a large value (see FIG. 1).
(Refer to the arrow T in (b)), the magnetic flux becomes a negligible value (leakage magnetic flux) in a portion outside the space between the magnets 12 and 13. In this conductive plate 11, the shaft 1
On the other side centered at 03, two magnets 14 and 15
Are fixedly arranged, but the arrangement method is such that the magnets 12 and 1
3, the description is omitted. As a result of disposing the magnets 12 to 15 in this way, the conductive plate 11
When the shaft 103 vibrates as shown by an arrow d in FIG. 1B around the center axis of rotation of the shaft 103, the magnetic flux that changes in the short side direction of the conductive plate 11 crosses vertically.

In the engraving head having such a configuration, an engraving signal as described in the section of the prior art is applied to the coil 108 (FIG. 1).
(See (a)), the shaft 103 vibrates about its central axis (see arrow A). According to the vibration of the shaft 103, the diamond bite 101
Is an arrow B about the center axis of the shaft 103.
Vibrates as shown by. This diamond bite 101
The cell is engraved on the surface of the gravure cylinder arranged in the vicinity by the displacement amount due to the vibration.

In the engraving head shown in FIG. 1A, when the shaft 103 vibrates, the shaft 103
Is vibrated in the direction of arrow d shown in FIG. As a result, as described above, the conductive plate 11 vibrates so as to vertically traverse the magnetic flux that changes in the short side direction.
A Lorentz force, which is a force in the direction opposite to the direction of motion, is generated. The magnitude of the Lorentz force is exactly proportional to the movement speed of the conductive plate 11, that is, the movement speed of the diamond cutting tool 101. Therefore, a step-like density signal (FIG. 1)
1 (b)), the diamond tool 101 tends to overshoot due to its transient response. However, the above-mentioned Lorentz force is generated in the magnetic damper, and the diamond tool 101 quickly overshoots. To dump. In this magnetic damper,
Since a damping effect having a strength proportional to the movement speed of the diamond cutting tool 101 is obtained, it is not necessary to always perform strong damping to deteriorate the rising characteristics of the engraving head. Thereby, the diamond bite 101
Indicates that even if the density signal (see FIG. 11B) rises rapidly, the surface of the gravure cylinder
It is possible to engrave cells of a volume that exactly follows the density signal (see the cell on the leftmost side in FIG. 11D).

The magnetic damper shown in FIG. 1A generates a damping force without contact between the conductive plate 11 and each of the magnets 12 to 15, so that the magnetic damper is not provided between the conductive plate 11 and each of the magnets 12 to 15. Does not cause unnecessary wear. As a result, the durability of the magnetic damper increases. The magnetic damper also generates a damping force that is relatively independent of the ambient temperature of the engraving head, as compared to a conventional damping mechanism. As a result, the magnetic damper can always generate a good damping force regardless of the temperature of the installation location of the gravure engraving system. Further, the conventional damping mechanism has a characteristic that the damping rate varies depending on the vibration frequency of the shaft 103. However, since the magnetic damper does not have such characteristics, even if the vibration frequency of the shaft 103 (the frequency of the engraving signal) is increased, a good damping force can be generated.

FIG. 2 is a diagram for explaining a second embodiment of the present invention. In particular, FIG. 2A is a perspective view showing the engraving head according to the present embodiment. In particular, FIG.
FIG. 2B is a diagram illustrating a configuration when the magnetic damper included in the engraving head is viewed from the direction of arrow C illustrated in FIG. 2A, the engraving head differs from that shown in FIG. 10 in that it has a magnetic damper. Since there is no other difference, the corresponding components are denoted by the same reference numerals and the description thereof will be omitted. Hereinafter, the magnetic damper will be described in detail. This magnetic damper is made of a circular conductive flat plate (hereinafter referred to as a conductive plate) 2.
1 and a plurality of magnet pairs 22 composed of a pair of magnets.

The conductive plate 21 is made of aluminum, copper, or the like, and is fixedly attached to the shaft 103. More specifically, the conductive plate 21 includes the stylus 102
And the rotor 105 is fixed so that the center thereof coincides with the central axis of the shaft 103 and the conductive plate 21 forms a plane perpendicular to the central axis of the shaft 103. It is attached.

A plurality of pairs of two magnet pairs 22 are fixedly arranged on the conductive plate 21 attached in this manner (FIG. 2 shows a configuration for fixing each magnet pair 22). , Not shown for clarity of illustration). Each magnet pair 22 has the same rectangular parallelepiped shape. For example, FIG.
In (a), the magnet pair 22 including the magnets 22a and 22b includes a surface on the N pole side (the lower surface in the present embodiment) of the magnet 22a and a surface on the S pole side of the magnet 22b (in the present embodiment, (Upper surface) so as to sandwich the conductive plate 21 therebetween. However, the lower surface of the magnet 22a and the upper surface of the magnet 22b face each other with the conductive plate 21 interposed therebetween, and are spaced apart by a certain distance so as not to contact the conductive plate 21 (see FIG. 2B). As typified by the magnet pairs 22a and 22b, each magnet pair 22 has a surface (lower surface) on the N pole side of each magnet disposed on the upper surface side of the conductive plate 21 and a lower surface side of the conductive plate 21. The conductive plate 21 is fixedly arranged so as to sandwich the conductive plate 21 between the respective magnets to be arranged and the surface (upper surface) on the S pole side. However, the lower surface of each magnet disposed on the upper surface side of the conductive plate 21 and the upper surface of each magnet disposed on the lower surface side thereof are opposed to each other and are separated by a predetermined distance so as not to contact the conductive plate 21. Is done. Further, each magnet pair 22 is spaced apart from the adjacent magnet pair 22 by a predetermined distance e (see FIG. 2B) and arranged in an annular manner.

By arranging the conductive plate 21 and the plurality of pairs of magnets 22 as described above, the magnetic flux between each pair of magnets 22 becomes large as in the first embodiment (see FIG. b), the arrow T), and the magnetic flux in the portion deviating from between the magnet pairs 22 becomes a negligible value (leakage magnetic flux). As a result, when the conductive plate 21 vibrates in the direction of arrow d in FIG. 1B around the center axis of the shaft 103 as the center of rotation, the conductive plate 21 vertically crosses the magnetic flux that changes in the circumferential direction of the conductive plate 21. Become.

In the magnetic damper shown in FIG. 2A, not only the effects described in the first embodiment can be obtained, but also many magnets are arranged on the conductive plate 21. A larger damping force can be obtained as compared with the form.

FIG. 3 is a diagram for explaining a third embodiment of the present invention. In particular, FIG. 3A is a perspective view showing the engraving head according to the present embodiment. In particular, FIG.
FIG. 3B is a diagram illustrating a configuration when the magnetic damper included in the engraving head is viewed from the direction of arrow C illustrated in FIG. 3A, the engraving head differs from that shown in FIG. 10 in that it has a magnetic damper. Since there is no other difference, the corresponding components are denoted by the same reference numerals and the description thereof will be omitted. Hereinafter, the magnetic damper will be described in detail. This magnetic damper is made of a circular conductive flat plate (hereinafter referred to as a conductive plate) 3
1 and two annular magnets 32 and 33.

The conductive plate 31 is the same as the conductive plate 21 described in the second embodiment, and a detailed description thereof will be omitted. The annular magnets 32 and 33 have the same shape as each other, and are configured such that N-poles and S-poles alternately appear on the respective annular surfaces along the circumferential direction. The two annular magnets 32 and 33 configured as described above sandwich the conductive plate 31 between one annular surface of the annular magnet 32 and one annular surface of the annular magnet 33. Fixedly arranged (note that FIG. 3
Describes a configuration for fixing the annular magnet pairs 32 and 33,
Not shown for clarity of illustration). However, the annular surfaces of the annular magnet 32 and the annular magnet 33 face each other via the conductive plate 31 and are arranged at a predetermined distance so as not to contact the conductive plate 31 (see FIG. 3B). Further, at this time, the N pole and S
The pole portion is an S pole and an N pole on the annular surface of the annular magnet 33.
It faces the pole part.

The two annular magnets 32 arranged in this manner
And 33, the magnetic flux in the direction (upward direction) from the annular magnet 33 toward the annular magnet 32 (the arrow T in FIG. 3B).
0) and the magnetic flux in the direction (downward direction) from the annular magnet 32 to the annular magnet 33 (see the arrow T1 in the figure) appear alternately along the circumferential direction of the conductive plate 31. As a result, when the conductive plate 31 vibrates around the center axis of the shaft 103 as the center of rotation (in FIG. 3B, the arrow d
Reference), and vertically crosses the magnetic flux that changes in the circumferential direction of the conductive plate 31.

The magnetic damper shown in FIG. 3 (a) not only provides the effect described in the first embodiment, but also allows the conductive plate 31 to have two types of magnetic fluxes whose directions are opposite to each other (FIG. 3).
(B), since it moves across the arrows T0 and T1), a larger damping force can be obtained as compared with the first and second embodiments.

FIG. 4 is a diagram for explaining a fourth embodiment of the present invention. In particular, FIG. 4A is a perspective view showing the engraving head according to the present embodiment. In particular, FIG.
FIG. 4B shows a magnetic damper provided in the engraving head.
It is a figure which shows the structure when the cross section along line CC 'shown to (a) is seen from the direction of arrow D. In FIG. 3A, the engraving head is different from that shown in FIG.
The third embodiment is different from the first embodiment in that a shaft 41 is provided in place of the 03 and a single annular magnet 42 is further provided. Since there is no other difference, the corresponding components are denoted by the same reference numerals and the description thereof will be omitted. In the present embodiment, the shaft 41 and the annular magnet 42 constitute a magnetic damper. Hereinafter, the magnetic damper will be described in detail.

The shaft 41 itself has a cylindrical shape and is made of a conductor. Except for this point, there is no difference between the shaft 41 and the shaft 103 shown in FIG. Further, the annular magnet 42 is configured such that N poles and S poles alternately appear along the circumferential direction of a through hole formed inside. The diameter of the through hole is designed to be larger than the diameter of the shaft 41. The shaft 41 is inserted into the through-hole of the annular magnet 42 so that the central axes of the two coincide. In addition, the annular magnet 42
Is fixed at a position where the shaft 41 is inserted (FIG. 4 does not show a configuration for fixing the pair of annular magnets 42 from the viewpoint of clarification of the drawing). As a result, the outer peripheral surface of the shaft 41 and the inner peripheral surface (through hole) of the annular magnet 42 are arranged at a fixed interval without contact.

By arranging the shaft 41 and the annular magnet 42 as described above, the adjacent N is formed in the through-hole portion of the annular magnet 42 as shown by the arrow T in FIG.
Magnetic flux is generated between the pole and the south pole. As a result, when the shaft 41 vibrates around the central axis as shown by an arrow A (see FIG. 4A), the conductor (the shaft 4)
The outer peripheral portion of 1) vertically crosses the magnetic flux changing in the outer peripheral direction.

In the magnetic damper shown in FIG. 4A, not only the effects described in the first embodiment can be obtained, but also because the shaft 41 itself is made of a conductor, the magnetic damper itself can be reduced in size. Can be

FIG. 5 is a diagram for explaining a fifth embodiment of the present invention. In particular, FIG. 5A is a perspective view showing the engraving head according to the present embodiment. In particular, FIG.
FIG. 5B shows a magnetic damper provided in the engraving head, as shown in FIG.
It is a figure which shows the structure when the cross section along line CC 'shown to (a) is seen from the direction of arrow D. 5A, the engraving head differs from that shown in FIG. 10 in that it has a magnetic damper. Since there is no other difference, the corresponding components are denoted by the same reference numerals and the description thereof will be omitted. Hereinafter, the magnetic damper will be described in detail. This magnetic damper includes a sleeve 51 made of a conductor and one annular magnet 52.

The sleeve 51 is made of a conductor having at least an outer periphery formed in a ring shape, for example, a ring-shaped conductor, and has a through hole in a central portion. The shaft 103 is inserted into the through hole of the sleeve 51 and is fixed to the sleeve 51. The annular magnet 52 has the same configuration as the annular magnet 42 described in the fourth embodiment, and a description thereof will be omitted. The diameter of the through hole of the annular magnet 52 is designed to be larger than the outer diameter of the annular sleeve 51. The sleeve 51 fixed to the shaft 103 is inserted through the through-hole of the annular magnet 52 so that the center axes of the two coincide. The annular magnet 52 is
It is fixed at the position where the shaft 41 is inserted.
Does not show a configuration for fixing the annular magnet pair 52 from the viewpoint of clarification of the drawing). As a result, the outer peripheral surface of the sleeve 51 and the inner peripheral surface (through hole) of the annular magnet 52 are arranged at a constant interval without contact (see FIG. 5B). By arranging the sleeve 51 and the annular magnet 52 as described above, as shown by an arrow T in FIG. Generates magnetic flux. as a result,
When the sleeve 51 oscillates about the central axis of the shaft 103 as shown by an arrow A (see FIG. 4A),
The outer peripheral portion of the conductor (sleeve 51) vertically crosses the magnetic flux changing in the outer peripheral direction.

The magnetic damper shown in FIG. 5 (a) can not only obtain the effects described in the first embodiment, but also can make the shaft itself a conductor compared to the fourth embodiment. It is effective when it cannot be manufactured. Further, in this magnetic damper, even if the shaft 103 itself can be made of a conductor in FIG. 5A, a better damping effect can be obtained by fixing the sleeve 51 around the shaft 103. be able to.

FIG. 6 is a diagram for explaining a sixth embodiment of the present invention. In particular, FIG. 6A is a perspective view showing the engraving head according to the present embodiment. In particular, FIG.
FIG. 6B is a diagram illustrating a configuration when the magnetic damper included in the engraving head is viewed from the direction of arrow C illustrated in FIG. 6A, the engraving head differs from that shown in FIG. 10 in that it has a magnetic damper. Since there is no other difference, the corresponding components are denoted by the same reference numerals and the description thereof will be omitted. Hereinafter, the magnetic damper will be described in detail. The magnetic damper is a flat plate of a rectangular conductor (hereinafter, referred to as a conductive plate).
61 and four magnets 6 having the same rectangular parallelepiped shape
2 to 65.

The conductive plate 61 has the same structure as the conductive plate 11 described in the first embodiment, and
, And a detailed description thereof will be omitted. In the conductive plate 61 attached in this manner, two magnets 62
And 63 are fixedly arranged. Two magnets 62 and 6
3 is fixed so that the surface on the N pole side and the surface on the S pole side are adjacent and form the same surface. Such two magnets 6
2 and 63 are the N pole side of the magnet 62 and the magnet 63
6 and the upper surface of the conductive plate 11 are opposed to each other, and are fixedly arranged at a predetermined distance so as not to contact the conductive plate 11 (see FIG. 6B). FIG.
Does not show a configuration for fixing the magnets 62 and 63 from the viewpoint of clarification of the drawing.

As shown in FIG. 6B, the conductive plate 6
1 has a short side having a length L1, and the magnets 62 and 63 have short sides having a length L2. In order to constitute the magnetic damper, it is preferable that the length L1 is designed to be longer than the length 2 × L2, and that both ends of the conductive plate 61 protrude from immediately below the magnets 62 and 63. As a result, the direction of the magnetic flux is reversed immediately below the magnets 62 and 63 (see the arrow T in FIG. 1B). On the other side of the conductive plate 61 around the shaft 103, two magnets 64 and 65 are fixedly arranged in the same manner as the magnets 62 and 63 described above. As a result, the conductive plate 6
1 indicates that when the shaft 103 oscillates about its central axis as a rotation center and oscillates as shown by an arrow d in FIG.
The magnetic flux that changes in the direction of the short side of the conductive plate 61 crosses vertically.

The magnetic damper shown in FIG. 6A not only obtains the effect described in the first embodiment, but also provides the magnets 62 to 65 only on the upper surface (or lower surface) of the conductive plate 61.
Is adopted, there is an effect that a limited space in the magnetic damper can be effectively used as compared with the first embodiment.

FIG. 7 is a view for explaining a sixth embodiment of the present invention. In particular, FIG. 7A is a perspective view showing the engraving head according to the present embodiment. In particular, FIG.
FIG. 8B is a diagram showing a configuration when the magnetic damper provided in the engraving head is viewed from the direction of arrow C shown in FIG. 7A, the engraving head differs from that shown in FIG. 10 in that it has a magnetic damper. Since there is no other difference, the corresponding components are denoted by the same reference numerals and the description thereof will be omitted. Hereinafter, the magnetic damper will be described in detail. The magnetic damper is a flat plate of a rectangular conductor (hereinafter, referred to as a conductive plate).
71, a magnet 72, and ferromagnetic substances 73 and 74.

The conductive plate 71 has the same configuration as the conductive plate 11 described in the first embodiment.
, And a detailed description thereof will be omitted. In addition, the magnet 72 is fixedly arranged at a position away from the shaft 103 (note that FIG. 7 does not show a configuration for fixing the magnet 72 from the viewpoint of clarification of the drawing). One end of an “L” -shaped ferromagnetic body 73 is fixed to the N-pole side surface of the magnet 72. The ferromagnetic material 73 is disposed so as to extend from the N-pole side surface of the magnet 72 to immediately above the conductive plate 71, and the shaft 1
It branches into two so as not to inhibit the vibration of 03. A surface 731 (see FIG. 7B) that constitutes the other end of the ferromagnetic body 73 and is disposed directly above the conductive plate 71 faces the upper surface of the conductive plate 71 and does not contact the conductive plate 71. As shown in FIG. Also, the magnet 7
One end of a ferromagnetic body 74 having the same shape as the ferromagnetic body 73 is fixed to the surface on the S pole side of the second. This ferromagnetic material 74
Are arranged so as to extend from the surface on the S-pole side of the magnet 72 to immediately below the conductive plate 71, and are branched into two on the way.
A surface 741 (see FIG. 7B) that constitutes the other end of the ferromagnetic body 74 and is disposed immediately below the conductive plate 71 faces the lower surface of the conductive plate 71 and does not contact the conductive plate 71. As shown in FIG. as a result,
The magnetic flux generated by the magnet 72 is guided by the two magnetic bodies 73 and 74 and is linked by the conductive plate 71.

Further, as shown in FIG.
1 has a short side having a length L1, and the surfaces 731 and 741 have short sides having a length L2. In order to constitute the magnetic damper, the length L1 is designed to be longer than the length L2, and the conductive plate 7 is disposed immediately below the surface 731 and directly above the surface 741.
It is preferable that both ends of 1 are arranged so as to protrude.
As a result, the magnetic flux has a large value between the two surfaces 731 and 741 (see the arrow T in FIG. 7B), but the magnetic flux is negligible in a portion deviating from between the surfaces 731 and 741. Value (leakage flux). As a result, when the conductive plate 71 oscillates about the center axis of the shaft 103 as a rotation center as shown by an arrow d in FIG. 7B, the conductive plate 71 vertically crosses the magnetic flux that changes in the short side direction of the conductive plate 71. Becomes

In the magnetic damper shown in FIG. 7A, not only the effects described in the first embodiment can be obtained, but also the magnet can be arranged at a position distant from the shaft 103. Compared with the first embodiment and the like, there is no restriction on the size of the magnet to be arranged. Therefore, the present magnetic damper can obtain a larger damping force.

FIG. 8 is a diagram for explaining an eighth embodiment of the present invention. In particular, FIG. 8A is a perspective view showing the engraving head according to the present embodiment. In particular, FIG.
FIG. 9B is a diagram showing a configuration when the magnetic damper provided in the engraving head is viewed from the direction of arrow C shown in FIG. 8A, the engraving head differs from that shown in FIG. 10 in that it has a magnetic damper. Since there is no other difference, the corresponding components are denoted by the same reference numerals and the description thereof will be omitted. Hereinafter, the magnetic damper will be described in detail. This magnetic damper is formed of a circular conductive flat plate (hereinafter referred to as a conductive plate) 8.
1, an electromagnet 82, and four partial annular magnet portions 83 to 86
And

The conductive plate 81 has the same configuration as the conductive plate 21 described in the second embodiment.
, And a detailed description thereof will be omitted. In addition, the electromagnet 82 is fixedly arranged at a position away from the shaft 103 (note that FIG. 8 does not show a configuration for fixing the electromagnet 82 from the viewpoint of clarifying the drawing). One end of an “L” -shaped ferromagnetic body 821 is fixed to the N pole side of the electromagnet 83. The ferromagnetic body 821 is disposed so as to extend from the N pole side of the electromagnet 82 to immediately above the conductive plate 81, and is branched into two portions so as not to hinder the vibration of the shaft 103 on the way. A surface 822 (see FIG. 8B), which constitutes the other end of the ferromagnetic body 821 and is disposed immediately above the conductive plate 81, faces the upper surface of the conductive plate 81 and does not contact the conductive plate 71. As shown in FIG.

One end of a ferromagnetic material 823 having the same shape as the ferromagnetic material 821 is fixed to the S pole side of the electromagnet 82. The ferromagnetic material 823 is disposed so as to extend from the S pole side of the electromagnet 82 to immediately below the conductive plate 81, and is branched into two in the middle. And the ferromagnetic material 823
And the other end of the surface 8 disposed directly below the conductive plate 81
The reference numeral 24 (see FIG. 7B) faces the lower surface of the conductive plate 81, and is arranged at a predetermined distance so as not to contact the conductive plate 81. As a result, the magnetic flux generated by the electromagnet 82 is guided by the two ferromagnetic bodies 821 and 823, and is linked by the conductive plate 81.

The partial annular magnets 83 to 86 have the same shape as each other, and each partial annular magnet
It is configured such that the N pole and the S pole alternately appear along the arc direction. The two partial annular magnets 83 and 84 configured as described above include a conductive plate 81 between one partial annular surface of the partial annular magnet 83 and one partial annular surface of the annular magnet 84. (FIG. 8 shows the pair of partial annular magnets 83 and 8
4 is not shown from the viewpoint of clarification of the drawing). However, the partial annular surfaces of the partial annular magnets 83 and 84 are opposed to each other via the conductive plate 81 and are arranged at a predetermined distance so as not to contact the conductive plate 81 (see FIG. 8B). Further, at this time, the partial annular magnet 8
The N-pole and S-pole portions of the partial annular surface 3 face the S-pole and N-pole portions of the partial annular magnet 84. Since the partial annular magnets 85 and 86 are arranged on the opposite side of the conductive plate 81 about the shaft 103 in the same manner as the partial annular magnets 83 and 84, the description is omitted.

As described above, the four partial annular magnets 83 to 83
86 is arranged with respect to the conductive plate 81, so that the partial annular magnets 8 are located between the partial annular magnets 83 and 84.
The magnetic flux in the direction from 3 toward the partial annular magnet 84 and the magnetic flux in the opposite direction appear alternately along the circumferential direction of the conductive plate 81. The partial annular magnets 85 and 86
A magnetic flux similar to the magnetic flux appearing between the partial annular magnets 83 and 84 also appears during the period. As a result, when the shaft 103 vibrates as indicated by an arrow A about the center axis of the shaft 103 as a rotation center, the conductive plate 81 vibrates as indicated by an arrow d in FIG. The magnetic flux generated by the magnetic flux 86 and changing in the circumferential direction of the conductive plate 81 crosses the magnetic flux vertically. In the present embodiment, the electromagnet 82
Since only the magnetic flux is insufficient, the annular magnets 83 to 86 are used as an auxiliary. However, when only the electromagnet 82 is sufficient, the auxiliary magnet need not be used.

The magnetic damper shown in FIG. 8A can not only obtain the effects described in the first embodiment, but also apply the electromagnet 82, so , The magnetic force of the electromagnet 82 can be changed. Therefore, the present magnetic damper can dynamically change the generated Lorentz force. Therefore,
When the vibration characteristics of the engraving head fluctuate due to the replacement of the diamond cutting tool 101, or when the material of the gravure cylinder is different, it is also possible to adjust the magnetic damper by performing trial engraving while adjusting the current value flowing through the coil 825. it can.

In the magnetic dampers according to the first to eighth embodiments, the conductor portion and the magnet portion must be formed in non-contact, and a certain gap is formed between the two. However, the air layer existing in this gap
This is a large resistance to the magnetic flux linked by the conductor portion. As a result, there is a problem that the damping force obtained by the magnetic damper according to each embodiment is reduced. In order to solve such a problem, a magnetic damper according to a ninth embodiment is configured. FIG. 9 is a view for explaining the ninth embodiment of the present invention. In FIG. 9, the magnetic damper according to the first embodiment is taken as an example from the viewpoint of concrete description. Therefore, in FIG. 9, the same reference numerals are given to the components corresponding to those shown in FIG. As shown in FIG. 9, a magnetic fluid ML is inserted between the conductor 11 and the magnets 12 and 13 disposed immediately above and below the conductor 11. At this time, since the magnetic fluid ML does not leak from between the magnets 12 and 13 due to the magnetic force, it does not need to be specially sealed. by this,
In this embodiment, the magnetic resistance can be further reduced. Note that, depending on the type of the magnetic fluid ML, the viscosity contributes, so that there is a possibility that the Lorentz force (damping force) obtained by the magnetic damper can be further increased.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a second embodiment of the present invention.

FIG. 3 is a diagram for explaining a third embodiment of the present invention.

FIG. 4 is a diagram for explaining a fourth embodiment of the present invention.

FIG. 5 is a diagram for explaining a fifth embodiment of the present invention.

FIG. 6 is a diagram for explaining a sixth embodiment of the present invention.

FIG. 7 is a diagram for explaining a seventh embodiment of the present invention.

FIG. 8 is a diagram for explaining an eighth embodiment of the present invention.

FIG. 9 is a diagram for explaining a ninth embodiment of the present invention.

FIG. 10 is a perspective view showing a configuration of a conventional engraving head.

11 is a diagram for explaining a carry signal, a step-like density signal, and an engraving signal generated outside the engraving head shown in FIG.

FIG. 12 is a diagram showing various damping mechanisms conventionally proposed.

[Explanation of symbols]

 101: Diamond tool 103, 41: Shaft 11, 21, 31, 61, 71, 81: Conductive plate 12-15, 62-65, 72: Magnet 22: Magnet pair 32, 33, 42, 52: Annular magnet 51: Sleeve 73, 74, 821, 823: Ferromagnetic substance 82: Electromagnet 83 to 86: Partially annular magnet

Claims (6)

[Claims] 1. An engraving head for engraving a cell on a surface of a gravure cylinder for producing an intaglio for gravure printing, comprising: a stylus having a needle-shaped cutting tool fixed to a tip thereof; By applying a driving force to the shaft and vibrating the shaft,
A driving force applying unit for vibrating the stylus and the cutting tool; and a magnetic damper for damping excessive vibration of the stylus, wherein the magnetic damper comprises: a conductor fixed to the shaft; And a magnet part that is arranged in a non-contact manner and generates a magnetic flux. When the shaft vibrates, the conductor traverses the magnetic flux generated by the magnet part, thereby generating Lorentz inside the conductor. An engraving head, wherein force damps excessive vibration of the stylus. 2. The conductor has a plate-like shape, the magnet unit has a pair of magnets, and the pair of magnets has one of N poles. 2. The engraving head according to claim 1, wherein the S pole is disposed so as to face the other S pole with the conductor interposed therebetween. 3. 3. The conductor has a cylindrical shape with the shaft as a central axis, and the magnet portion is arranged in an annular shape with N poles and S poles alternately arranged along the outer periphery of the conductor. The engraving head according to claim 1, further comprising a magnet. 4. The conductor has a plate-like shape, and the magnet unit has a magnet having an N pole and an S pole arranged so as to face any one surface of the conductor. The engraving head according to claim 1, characterized in that: 5. The engraving head according to claim 1, wherein the magnet section further includes an electromagnet, and the damping force can be changed according to a voltage applied to the electromagnet. 6. The engraving head according to claim 1, wherein a magnetic fluid is filled between the conductor and the magnet.