阅读说明：本技术 振动发生装置以及图像形成装置 (Vibration generating device and image forming apparatus ) 是由 星山勇一 于 2021-05-08 设计创作，主要内容包括：本发明提供能够准确地应对微小的振动的振动发生装置。包含固定的永久磁铁(47)及磁轭(49)和线圈(51),并且包含可动件(55),该可动件利用弹簧(53)支撑于磁轭并通过正反切换对线圈的通电来相对于磁轭进行振动,可动件的两端部(55a)在与磁轭的各组的前端(49h、49i、49j、49k)之间以均匀的第一间隙(t1)分别配置,至少四个截面呈泪珠状的弹簧(53)支撑可动件,可动件的中央部(55b)相对于线圈(51)的贯通孔(51a)具有均等的第二间隙(t2)地配置,第二间隙设定为在与第一间隙的关系中允许可动件的中央部的摆动的大小,在使可动件的两端部在第一间隙内振动时,可动件的中央部在第二间隙内摆动振动而使可动件进行跷跷板运动的振动。(The invention provides a vibration generator capable of accurately coping with minute vibration. Comprising a fixed permanent magnet (47), a yoke (49) and a coil (51), and comprising a movable element (55), the movable element is supported by the yoke by a spring (53) and vibrates with respect to the yoke by switching the energization of the coil in the forward and reverse directions, the two ends (55a) of the movable element are respectively arranged with a uniform first gap (t1) between the front ends (49h, 49i, 49j, 49k) of the groups of the magnetic yoke, at least four springs (53) with a teardrop-shaped section support the movable element, the center part (55b) of the movable element is arranged with a uniform second gap (t2) relative to the through hole (51a) of the coil (51), the second gap is set to a size which allows the swing of the center part of the movable element in the relation with the first gap, when both end portions of the movable element are vibrated in the first gap, the center portion of the movable element is vibrated in the second gap to vibrate the movable element for seesaw movement.)

1. A vibration generating device is characterized in that,

a permanent magnet, a yoke, and a coil on a fixed side, and a movable element on a movable side supported by the yoke via a spring and vibrating with respect to the yoke by switching the energization of the coil in the forward and backward directions,

the yoke has a pair of yokes, one end of each yoke is joined to the N pole and the S pole of the permanent magnet,

the other ends of the pair of yokes are symmetrically provided in pairs with a set of tips of the N pole and the S pole facing each other,

the yoke includes a coil fixing portion that is provided between the pair of the leading end groups and that centrally accommodates and fixes the coil,

the yoke includes spring support portions at least at four positions so as to be arranged symmetrically with respect to the tip end, the spring support portions supporting the springs on both sides of the coil fixing portion and between the coil fixing portion and the tip end,

the movable element has end portions symmetrically protruding on both sides of a central portion,

the two ends of the movable element are respectively arranged with a uniform first gap between the two ends and the front end of each group of the magnetic yoke,

the central part of the movable element is arranged on the coil fixing part,

the movable element has an arm portion for acquiring vibration which partially protrudes at one end portion,

the springs are provided with at least four springs according to the spring supporting parts,

the four springs are respectively provided with a tip part at one side and an arc part at the other side, and have the same shape with a teardrop shape in cross section,

the tip end of each spring is supported by each spring support part,

the arcuate portion of each spring supports the movable element on both sides of the central portion,

the coil is housed in the coil fixing portion and an outer peripheral portion of the coil is fixed to the yoke by resin,

a through hole for disposing the center part of the movable element is provided on the inner periphery of the coil,

the movable element is disposed so that the central portion has a uniform second gap with respect to the through hole,

the second gap is set to a size that allows the swing of the center portion of the movable element in relation to the first gap,

when both end portions of the movable element are vibrated in the first gap by switching the energization of the coil in the forward and backward directions, the center portion of the movable element is vibrated in the second gap by swinging, and the movable element is vibrated by seesaw movement.

2. Vibration generating device according to claim 1,

the inner peripheral portion of the through hole is formed flat by a resin coating material, and the opening edge portion is formed in an arc shape or a chamfered shape facing the arc-shaped portion of the spring by the resin coating material.

3. Vibration generating device according to claim 1,

the permanent magnet and the magnetic yoke are clamped by a pair of mounting brackets,

the pair of mounting brackets have openings corresponding to the coil fixing portions,

both side portions of the coil protrude outward of the opening of the mounting bracket,

the coil is fixed to an outer surface of the mounting bracket by resin.

4. An image engraving device comprising the vibration generating device according to any one of claims 1 to 3,

the vibration generating device is mounted so that the arm portion can vibrate in the Z-axis direction,

a drawing needle holder configured to be interlocked with the arm portion in the Z-axis direction via a connecting member in the Z-axis direction,

the stylus holder is supported by the front end of a support spring that allows Z-axis vibration,

the supporting spring is arranged in a manner that the base end is fixed on the fixing part and extends towards the drawing needle bracket in the transverse direction,

the tracing needle is supported by the tracing needle bracket,

the energization of the coil is switched based on an engraving signal, and the medium to be engraved is engraved by a relative movement in the X-axis, Y-axis, and Z-axis directions between the writing needle and the medium to be engraved that vibrates in the Z-axis direction based on the engraving signal.

5. An image engraving device comprising the vibration generating device according to any one of claims 1 to 3,

the vibration generating device is provided with two sets of vibration generating devices,

one of the two vibration generators is mounted so as to obtain vibration in a Z-axis direction, and the other is mounted so as to obtain vibration in an X-axis direction orthogonal to the Z-axis direction,

a drawing needle holder configured to be interlocked with an arm of the one vibration generating device that acquires vibration in the Z-axis direction via a connecting member in the Z-axis direction,

the needle holder is supported at the front end of a support spring which allows vibration in the Z-axis and X-axis directions,

the supporting spring is arranged in a manner that the base end is fixed on the fixing part and extends towards the drawing needle bracket in the transverse direction,

the tracing needle is supported by the tracing needle bracket,

an arm portion of the other vibration generating means for generating vibration in the X-axis direction is configured to be interlocked with the drawing needle holder in the X-axis direction via a connecting member in the X-axis direction,

the power supply to the coils of the one and the other vibration generating devices is switched based on the engraving signal, the other vibration generating device applies vibration in the X-axis direction to the drawing pin vibrated in the Z-axis direction by the one vibration generating device, and the medium to be engraved is engraved by relative movement in the X-axis, Y-axis, and Z-axis directions with respect to the medium to be engraved based on the engraving signal.

Technical Field

The present invention relates to a vibration generating device for obtaining minute vibrations and an image engraving device for engraving an engraved medium by relative motion between a stylus and the engraved medium using the vibration generating device.

Background

Conventionally, there is known an image engraving device for engraving an image on an engraved medium such as a booklet like a passport, a sheet like paper, a card like engraved medium, or the like for preventing forgery and providing an aesthetic value (for example, patent documents 1 and 2).

This image engraving device performs minute engraving using a stylus that vibrates based on an image signal obtained by converting image data into an electrical signal, and creates an image such as a photograph or a figure on an engraved medium.

Such an image engraving device uses a permanent magnet and an electromagnet as a vibration generating device, and the permanent magnet is attached to a base and configured to vibrate a movable element with respect to the permanent magnet to apply vibration to the writing stylus. That is, the electromagnet can vibrate the mover with respect to the permanent magnet by switching the magnetic poles of the mover by switching the energization of the coil supported by the mover in the forward and reverse directions.

However, since the coil vibrates together with the movable element, there is a limit to the response to minute vibration, which leads to a limit to accurate minute engraving and the like.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-289823

Patent document 2: japanese patent laid-open publication No. 2009-207955

Disclosure of Invention

Problems to be solved by the invention

The problem to be solved is that, since the coil is supported by the movable element on the vibration side, there is a limit to the response to minute vibrations.

Means for solving the problems

The present invention provides a vibration generating device including a permanent magnet on a fixed side, a yoke and a coil, and a movable element on a movable side supported by the yoke by a spring and vibrating with respect to the yoke by switching energization of the coil between a positive side and a negative side, the yoke including a pair of yokes having one end joined to an N-pole and an S-pole of the permanent magnet, the pair of yokes including, at the other end of the pair of yokes, a pair of groups of leading ends of the N-pole and the S-pole which are opposed to each other symmetrically, the yoke including a coil fixing portion which accommodates and fixes the coil at a center between the pair of the leading ends, the yoke including spring support portions which are arranged symmetrically with respect to the leading ends at least at four places, the spring support portions supporting the spring between the group and the leading end on both sides of the coil fixing portion, the movable element includes end portions symmetrically protruding on both sides of a central portion, both end portions of the movable element are disposed with a uniform first gap from the front end of each group of the yoke, the central portion of the movable element is disposed on the coil fixing portion, the movable element includes an arm portion locally protruding at one end portion for acquiring vibration, the springs include at least four springs according to the spring support portions, the at least four springs each have a same shape having a tip portion on one side and an arc portion on the other side and having a tear-drop shape in cross section, the tip portion of each spring is supported by each spring support portion, the arc portion of each spring supports the movable element on both sides of the central portion, the coil is housed in the coil fixing portion and an outer peripheral portion thereof is fixed to the yoke by resin, and a through hole for disposing the central portion of the movable element is provided on an inner periphery of the coil, the movable element is disposed such that the central portion has a second gap that is uniform with respect to the through hole, the second gap being set to a size that allows the central portion of the movable element to swing in relation to the first gap, and when both end portions of the movable element vibrate in the first gap by switching the energization of the coil in the forward and reverse directions, the central portion of the movable element vibrates in the second gap in a swinging manner, and the movable element vibrates in a seesaw motion.

Further, the image engraving device is provided with the vibration generating device, wherein the vibration generating device is mounted such that the arm portion vibrates in the Z-axis direction, and is provided with a stylus holder configured to be interlocked with the arm portion in the Z-axis direction via a connecting member in the Z-axis direction, the stylus holder being supported by a distal end of a support spring that allows vibration in the Z-axis direction, the support spring being disposed such that a proximal end thereof is fixed to a fixed portion and extends in a lateral direction toward the stylus holder, the stylus holder supporting a stylus, energizing the coil being switched based on an engraving signal, and the stylus vibrating in the Z-axis direction in conjunction with a seesaw movement of the movable element being operated by relative movement in the X-axis, Y-axis, and Z-axis directions with respect to the engraved medium based on the engraving signal, to engrave the engraved medium.

The effects of the invention are as follows.

With the above-described configuration, when both ends of the movable element are reasonably vibrated in the first gap by switching the energization of the coil between the normal and reverse directions, the center portion of the movable element can be oscillated and vibrated in the second gap. Therefore, more minute vibration of the movable element can be performed.

The image engraving device of the present invention switches energization to the coil based on the engraving signal, and can engrave the medium to be engraved by relative movement in the X-axis, Y-axis, and Z-axis directions based on the engraving signal between the writing needle vibrating in the Z-axis direction and the medium to be engraved.

Drawings

Fig. 1 is a schematic perspective view showing a main part of the image engraving device. (example 1)

Fig. 2 is a perspective view showing a relationship between the vibration generating device and the drawing needle. (example 1)

Fig. 3 is a perspective view of the vibration generating device. (example 1)

Fig. 4 is a side view of the vibration generating device. (example 1)

Fig. 5 is a front view of the vibration generating device. (example 1)

Fig. 6 is a front view of a yoke provided with an electromagnet. (example 1)

Fig. 7 is a perspective view of the yoke laminated body. (example 1)

Fig. 8 is a perspective view of the yoke plate. (example 1)

Fig. 9 is a perspective view of the mover stack. (example 1)

Fig. 10 is a perspective view of the movable plate. (example 1)

Fig. 11 is a front view of the movable plate. (example 1)

Fig. 12 is a perspective view of a tear-drop spring. (example 1)

Fig. 13 is a cross-sectional view of a tear-drop spring. (example 1)

Fig. 14 is a perspective view of the coil. (example 1)

Fig. 15 is a conceptual diagram of two vibration generators. (example 2)

Fig. 16 (a) is a schematic diagram of the resolution of an engraved image by the single solenoid method as a comparative example. (B) Is a schematic diagram of the resolution of the engraved image based on the two-solenoid method. (example 2)

Fig. 17 (a) is a schematic diagram of an engraved image by the single solenoid method as a comparative example. (B) Is a schematic diagram of an engraved image based on a two-solenoid approach. (example 2)

Fig. 18 is a graph showing a distribution map of signals of the addition circuit and the subtraction circuit. (example 2)

Fig. 19 (a) is a graph illustrating a signal diagram, and (B) is a graph illustrating a corresponding engraving pattern.

(example 2)

Description of the symbols

1-image engraving device, 5-X axis table, 7-Y axis table, 9-Z axis drive mechanism, 13-drawing needle, 19A, 19B-vibration generating device, 21-arm, 22-pin support block, 23-connecting member, 25-drawing needle holder, 27-support spring, 29-fixed block (fixed side), 47-permanent magnet, 49-yoke, 49 e-coil fixed part, 49f, 49 g-one end, 49h, 49i, 49j, 49 k-front end, 51-coil, 51 a-through hole aa, 51-inner peripheral part, 51 ab-opening edge, 53-spring, 53 a-tip part, 53B-arc part, 55-movable piece, 55 a-both end parts, 55B-central part, 57-spring support part, 59-mounting bracket, 59A-opening, 61-bolt-nut.

Detailed Description

The vibration generator of the present invention includes a permanent magnet on a fixed side, a yoke and a coil, and includes a movable element on a movable side supported by the yoke by a spring and vibrating with respect to the yoke by switching the energization of the coil in the forward and reverse directions, the yoke includes a pair of yokes, one end of each of which is joined to an N pole and an S pole of the permanent magnet, the pair of yokes includes a pair of front ends of the N pole and the S pole, the pair of yokes are symmetrically opposed to each other at the other ends of the pair of yokes, the yoke includes a coil fixing portion which is disposed between the pair of front ends and which accommodates and fixes the coil at a center thereof, the yoke includes spring support portions which are disposed symmetrically with respect to the front ends at least at four locations, the spring support portions support the spring on both sides of the coil fixing portion and between the pair of front ends, the movable element includes end portions symmetrically protruding on both sides of a central portion, both end portions of the movable element are disposed with a uniform first gap from the front end of each group of the yoke, the central portion of the movable element is disposed on the coil fixing portion, the movable element includes an arm portion locally protruding at one end portion for acquiring vibration, the springs include at least four springs according to the spring support portions, the at least four springs each have a same shape having a tip portion on one side and an arc portion on the other side and having a tear-drop shape in cross section, the tip portion of each spring is supported by each spring support portion, the arc portion of each spring supports the movable element on both sides of the central portion, the coil is housed in the coil fixing portion and an outer peripheral portion thereof is fixed to the yoke by resin, and a through hole for disposing the central portion of the movable element is provided on an inner periphery of the coil, the movable element is disposed such that the central portion has a second gap that is uniform with respect to the through hole, the second gap being set to a size that allows the central portion of the movable element to swing in relation to the first gap, and when both end portions of the movable element vibrate in the first gap by switching the energization of the coil in the forward and reverse directions, the central portion of the movable element vibrates in the second gap in a swinging manner, and the movable element vibrates in a seesaw motion.

The spring support portions may be provided at least at four positions in a symmetrical arrangement, and the number of the spring support portions may be further increased.

The number of the springs can be increased according to the increase of the number of the spring supporting parts.

The outer peripheral portion of the coil fixed to the yoke by resin may be present outside the through hole of the coil, and means an outermost peripheral portion, a side surface portion, and the like.

The size of the second gap may be a size that allows the central portion of the movable element to swing when both end portions of the movable element vibrate within the range of the first gap, and may be a size that is just large enough to allow the swing or larger. The second gap does not disappear at least until the first gap disappears due to vibration of the movable element and both end portions of the movable element abut on the front end of the yoke. The first and second gaps can disappear simultaneously.

The inner peripheral portion of the through hole is formed flat by a resin coating material, and the opening edge portion is formed in an arc shape facing the arc portion of the spring by the resin coating material. The arcuate shape of the opening stem portion can allow deformation of the arcuate portion of the spring in a restricted space, as can be the chamfered shape.

The permanent magnet and the yoke are held between a pair of mounting brackets on a fixed side, the pair of mounting brackets are provided with openings corresponding to coil fixing portions, both side portions of the coil protrude outward of the openings of the mounting brackets, and the coil is fixed to an outer surface of the mounting brackets by resin.

The image engraving device of the present invention is an image engraving device including the vibration generating device, wherein the vibration generating device is mounted such that the arm portion vibrates in the Z-axis direction, and includes a stylus holder configured to be interlocked with the arm portion in the Z-axis direction via a connecting member in the Z-axis direction, the needle holder is supported at the front end of a support spring which allows vibration in the Z-axis direction, the support spring is arranged in a manner that the base end is fixed to a fixed part and extends towards the needle holder in the transverse direction, the writing pin holder supports a writing pin, switches energization to the coil based on an engraving signal, and engraves the medium to be engraved by relative movement in the X, Y, and Z-axis directions between the writing pin and the medium to be engraved that vibrates in the Z-axis direction based on the engraving signal.

The connecting member may transmit vibration from the arm portion to the needle holder without interfering with the vibration.

The support spring allows the Z-axis vibration of the stylus holder.

The specific structure of the relative movement in the X-axis, Y-axis, and Z-axis directions between the writing needle and the medium to be engraved, which vibrates in accordance with the engraving signal, is arbitrary. That is, the support combination between the X-axis table driven in the X-axis direction, the Y-axis table driven in the Y-axis direction, and the Z-axis drive mechanism driven in the Z-axis direction, and the vibration generating device and the engraved medium is free.

For example, consider the following various combinations: a mode in which an engraved medium is supported by an X-axis table, and a vibration generating device is supported by a Y-axis table and a Z-axis drive mechanism; a mode in which an engraved medium is supported by a Y-axis table, and a vibration generating device is supported by an X-axis table and a Z-axis drive mechanism; and a system in which the engraved medium is supported by a Z-axis drive mechanism and a vibration generating device is supported by an X-axis table and a Y-axis table.

An image engraving device comprising the vibration generating device, wherein the vibration generating device comprises two vibration generating devices, one of the two vibration generating devices is mounted so as to obtain vibration in a Z-axis direction, and the other vibration generating device is mounted so as to obtain vibration in an X-axis direction orthogonal to the Z-axis direction, the image engraving device comprises a stylus holder configured to be interlocked with an arm portion of the one vibration generating device obtaining vibration in the Z-axis direction via a connecting member in the Z-axis direction, the stylus holder is supported by a distal end of a support spring allowing vibration in the Z-axis direction and the X-axis direction, the support spring is fixed at a proximal end to a fixed portion and is disposed so as to extend in a lateral direction toward the stylus holder, the stylus is supported by the stylus holder, and an arm portion of the other vibration generating device obtaining vibration in the X-axis direction is configured to be interlocked with the stylus holder in the X-axis direction via a connecting member in the X-axis direction, the power supply to the coils of the one and the other vibration generating devices is switched based on the engraving signal, the other vibration generating device applies vibration in the X-axis direction to the drawing pin vibrated in the Z-axis direction by the one vibration generating device, and the medium to be engraved is engraved by relative movement in the X-axis, Y-axis, and Z-axis directions with respect to the medium to be engraved based on the engraving signal.

[ example 1 ]

[ image engraving device ]

Fig. 1 is a schematic perspective view showing a main part of an image engraving device of embodiment 1 of the present invention. Fig. 2 is a perspective view showing a relationship between the vibration generating device and the drawing needle.

As shown in fig. 1 and 2, the image engraving device 1 includes a device main body (not shown) in which a control device and the like are stored, and includes an X-axis table 5, a Y-axis table 7, a Z-axis drive mechanism 9, and the like on an upper portion of the device main body.

The X-axis table 5 is placed on and fixed with an engraved medium and is reciprocated in the X-axis direction in a plane. The Y-axis table 7 reciprocates the engraving head 11 in the Y-axis direction orthogonal to the X-axis direction within a plane. The Z-axis drive mechanism 9 moves the engraving head 11 in the vertical direction.

The engraving head 11 has a stylus 13, vibrates the stylus 13 based on an input engraving signal, and engraves an image on an engraved medium by relative movement in the X-axis, Y-axis, and Z-axis directions with respect to the engraved medium based on the engraving signal. The engraving signal is a signal obtained by converting a digital signal of an image read from a photographic image or the like into an analog signal.

The engraving head 11 is movable in the vertical direction by a Z-axis drive unit such as a stepping motor, a timing belt, and a ball screw provided in the Z-axis drive mechanism 9 disposed at the rear thereof. The engraving head 11 is movable in the Y-axis direction, i.e., in the front-back direction, by a Y-axis table 7 driven by a Y-axis drive unit 15 disposed below the Z-axis drive mechanism 9. The Y-axis direction serves as the "line" direction relative to the scan direction of the engraved medium.

The X-axis table 5 is driven by an X-axis drive unit 15 and can move in the left-right direction, which is the X-axis direction. The X-axis direction serves as the "column" direction in the scanning direction with respect to the engraved medium. An engraved medium such as a passport or a card is held and fixed on the X-axis table 5.

Therefore, the writing needle 13 of the engraving head 11 vibrating in the Z-axis direction and the medium to be engraved can perform relative movement in the X-axis, Y-axis, and Z-axis directions.

The image engraving device 1 is mounted so that the engraving head 11 can vibrate in the Z-axis direction. Therefore, engraving head 11 is provided with vibration generating device 19. As shown in fig. 2, the vibration generating device 19 includes an arm 21 for acquiring vibration. A pin support block 22 is attached to the tip of the arm portion 21. The needle holder 25 is connected to the pin support block 22 via a connecting member 23 in the Z-axis direction. The connecting member 23 is a long wire rod made of rigid metal or the like capable of transmitting vibration in the Z-axis direction. Therefore, the drawing needle holder 25 is configured to be interlocked with the arm portion 21 in the Z-axis direction via the connecting member 23.

The needle holder 25 is supported at the tips of upper and lower support springs 27a and 27b that allow Z-axis vibration. Each of the support springs 27a and 27b is formed of a plate spring so as to allow vibration in the Z-axis direction, and includes a pair of leg portions in the X-axis direction in parallel. The base ends of the support springs 27a, 27b are fixed to a fixing block 29 as a fixing portion. That is, the support springs 27a and 27b are disposed so as to extend from the fixed block 29 toward the stylus holder 25 in the lateral direction. The stylus 13 is supported by the stylus holder 25.

One side of the vibration generating means 19 is fixed to the floating plate 33 by a plate spring member 31. The other side of the vibration generating device 19 is combined with the joint plate 35. The engagement plate 35 is combined with a drawing pin adjustment screw 37. The needle adjustment screw 37 is screwed to the floating plate 33, and the needle adjustment screw 37 can be rotated by a dial 39. The floating plate 33 is coupled to a frame 43 of the engraving head 11 via a leaf spring 41. The floating plate 33 is also fixed to the fixed block 29.

Therefore, the stylus 13, which switches energization to a coil described below based on an engraving signal and vibrates in the Z-axis direction in conjunction with vibration of seesaw movement of a movable element described below, engraves the medium to be engraved by relative movement in the X-axis, Y-axis, and Z-axis directions with respect to the medium to be engraved based on the engraving signal.

[ vibration generating device ]

Fig. 3 is a perspective view of the vibration generating device. Fig. 4 is a side view of the vibration generating device. Fig. 5 is a front view of the vibration generating device. Fig. 6 is a front view of a yoke provided with an electromagnet. Fig. 7 is a perspective view of the yoke laminated body. Fig. 8 is a perspective view of the yoke plate. Fig. 9 is a perspective view of the mover stack. Fig. 10 is a perspective view of the movable plate. Fig. 11 is a front view of the movable plate. Fig. 12 is a perspective view of a tear-drop spring. Fig. 13 is a cross-sectional view of a tear-drop spring. Fig. 14 is a perspective view of the coil.

As shown in fig. 1 to 5, the vibration generating device 19 includes a permanent magnet 47, a yoke 49, and a coil 51 on the fixed side, and includes a movable element 55 on the movable side, and the movable element 55 on the movable side is supported by the yoke 49 by a spring 53, and vibrates with respect to the yoke 49 by switching the energization of the coil 51 in the forward and backward directions. In this case, since the mover 55 is configured to vibrate with respect to the yoke 49, the permanent magnet 47, the yoke 49, and the coil 51 are referred to as a fixed side, and the mover 55 that can vibrate and move with respect to the fixed side is referred to as a movable side.

As shown in fig. 4 and 6, the permanent magnet 47 is formed by stacking three blocks 47a in a rectangular parallelepiped shape in series from top to bottom. Further, a plurality of blocks of permanent magnets may be arranged in parallel and coupled to the yoke 49.

As shown in fig. 3 to 8, the yoke 49 includes a pair of upper and lower yoke portions 49a and 49 b. As shown in fig. 6 to 8, the pair of yoke upper and lower portions 49A, 49b have a laminated structure of yoke plates 49A, respectively. The pair of yoke upper and lower portions 49a, 49b have a magnet mounting portion 49c formed on one side therebetween, and a mover arranging portion 49d and a coil fixing portion 49e formed on the other side.

The magnet mounting portion 49c is formed in a rectangular shape with one side open. The upper portion of the magnet mounting portion 49c is formed by one end 49f of the yoke upper portion 49a, and the lower portion thereof is formed by one end 49g of the yoke lower portion 49 b. One end 49f of the yoke upper portion 49a is joined to an upper end pole, for example, an N-pole, of the permanent magnet 47 disposed in the magnet mounting portion 49 c. One end 49g of the yoke lower portion 49b is joined to a pole, for example, an S pole, at the lower end of the permanent magnet 47. That is, one ends 49f and 49g of the upper yoke portion 49a and the lower yoke portion 49b are joined to the N pole and the S pole of the permanent magnet 47, respectively.

The mover arrangement portion 49d is formed between the other ends of the yoke upper portion 49a and the yoke lower portion 49b in the Y-axis direction. The group of tips 49h and 49i and the group of tips 49j and 49k are provided so as to face the upper and lower portions of the mover arranging portion 49 d. The group of the leading ends 49h and 49i and the group of the leading ends 49j and 49k form a pair in the Y-axis direction. The number of pairs is not particularly limited, and in addition to the illustrated pair of groups, the number of pairs may be increased to form two pairs of groups symmetrically. That is, the pair of yokes, i.e., the yoke upper portion 49a and the yoke lower portion 49b, have the pair of front ends of the N pole and the S pole facing each other symmetrically. In the drawing, the front ends 49h and 49j of the upper yoke portion 49a are N-poles, and the front ends 49i and 49k of the lower yoke portion 49b are S-poles.

The yoke 49 includes a coil fixing portion 49e that centrally accommodates and fixes the coil 51 between the pair of the group of the front ends 49h and 49i and the pair of the group of the front ends 49j and 49 k. The coil fixing portion 49e is formed in a vertically and horizontally symmetrical shape, and penetrates the yoke 49 in the X-axis direction. The coil fixing portion 49e is formed by a downward notch portion 49ea formed on the other side of the yoke upper portion 49a and an upward notch portion 49eb formed on the other side of the yoke lower portion 49 b. The cutout portions 49ea and 49eb are located on both upper and lower sides of the movable element disposition portion 49 d. In this case, the other side is the side of the magnet mounting portion 49 c.

The yoke 49 includes spring support portions 57 at least at four positions so as to be arranged symmetrically with respect to the front ends 49h, 49i, 49j, and 49 k. The spring support portions 57 support the springs 53 on both sides of the coil fixing portion 49e in the Y axis direction between the group of the leading ends 49h and 49i and the group of the leading ends 49j and 49 k. The spring support portions 57 at four positions are formed in the same shape. The spring support portions 57 at the two upper sides are inclined so as to be directed to the lower inner side of the downward cutout portion 49 ea. The spring support portions 57 at the two lower positions are inclined so as to be directed to the upper inner side of the upward cutout portion 49 eb. Each spring support portion 57 is cut so as to form two sides of a triangular shape at the side of the cut between the coil fixing portion 49e and the leading ends 49h, 49i, 49j, 49 k. The shape of the spring support portion 57 corresponds to the shape of the tip end side of the spring 53 described below. The spring support portion 57 is configured to fit and support the tip end portion of the spring 53 without a gap.

The permanent magnet 47 and the yoke 49 are held between a pair of mounting brackets 59, and the mounting brackets 59 are fastened together by bolts and nuts 61 to complete the assembly. Openings 59a corresponding to the coil fixing portions 49e are formed in the pair of mounting brackets 59, and the coil fixing portions 49e are opened outside the pair of mounting brackets 59. The fastening portion 59b of the mounting bracket 59 is fastened and fixed to the floating plate 35 of the engraving head 11 as the fixed side.

As shown in fig. 3 to 5 and 9 to 11, the mover 55 is a laminated body of a moving plate 55A. The arm portion 21 is integrally provided at the center of one end of the movable element 55 in the Y axis direction of the laminated body. The arm portion 21 is formed to partially protrude from the movable piece 55. In fig. 9, two movable plates 55A integrally protrude from the center portion side, and are provided for obtaining vibration.

The movable element 55 includes end portions 55a protruding symmetrically in the Y-axis direction on both sides of the center portion. Both end portions 55a of the mover 55 are disposed between the front ends 49h and 49i and between the front ends 49j and 49k of the respective sets of the yoke 49 with a uniform first gap t1, respectively. The movable element 55 has a central portion 55b formed to have a wide vertical width. The central portion 55b is disposed between the downward notch 49ea and the upward notch 49eb of the coil fixing portion 49 e. Spring receiving portions 55c formed by inclined steps are formed between the left and right end portions 55a and the center portion 55b of the mover 55. The spring seat 55c supports the arc-shaped portion of the spring 53 in contact therewith.

The springs 53 are provided with at least four springs by the spring support portions 57. The spring 53 and the spring support portion 57 can be additionally provided while securing an installation space in the Y-axis direction.

As shown in fig. 4, 12, and 13, the spring 53 is formed of a plate spring and is formed in line symmetry with a teardrop-shaped cross section. In the cross section of the spring 53, a tip portion 53a is provided on one side and an arc-shaped portion 53b is provided on the other side. The tip portion 53a is an abutting portion formed by bending the plate spring. The arc-shaped portion 53b is formed along a circle of radius r, and the tip portion 53a is formed along a tangent of the circle of radius r. The shortest distance between the apex 53ab of the tip portion 53a and the circle of the radius r is set smaller than the radius r.

The tip portion 53a is fitted to the spring support portion 57 substantially without a gap, and both side surfaces of the tip portion 53a are supported in contact with the spring support portion 57. The arc portion 53b has a curvature of a spring seat portion 55c supporting the movable element 55.

When the spring 53 is interposed between the spring support portion 57 and the spring seat portion 55c, the symmetry line of the spring 53 is set to be inclined.

The spring 53 is formed such that both side portions 53c of the tip portion 53a protrude in the longitudinal direction from the arc portion 53b side. Therefore, the arc-shaped portion 53b can be reliably brought into contact with the spring seat portion 55c while the tip portion 53a side is reliably supported by the spring support portion 57.

In this way, the arcuate portion 53b of the spring 53 supported by the spring support portion 57 supports the movable element 55, and the first gap t1 is set.

As shown in fig. 3 to 5 and 14, the coil 51 is wound in a rectangular shape. The coil 51 can be wound in a free shape, and can be wound in an elliptical shape or the like on the outer circumference. The winding direction of the coil 51 is a direction intersecting the arrangement direction of the movable element 55, and the vertical and horizontal directions of the coil 51 in the drawing are the ZX-axis directions. The coil 51 has a through hole 51a in which a central portion 55b of the mover 55 is disposed on a rectangular inner periphery. The through-hole 51a of the coil 51 constitutes a fine plane by winding the wire of the coil 51. The coil 51 is entirely coated with resin.

The inner peripheral portion 51aa of the through hole 51a is formed flat by coating with resin, and the opening edge portion 51ab is formed in an arc shape or a chamfered shape by coating with resin. The opening edge 51ab has an arcuate shape or a chamfered shape, and the like, which faces the arcuate portion 53b of the spring 53. By this facing, the gap between the coil 51 and the spring 53 can be further narrowed.

The flatness of the inner peripheral portion 51aa of the through hole 51a, the arcuate shape or chamfered shape of the opening edge portion 51ab, and the like allow the swing range of the central portion 55b of the movable element 55 accurately, and allow the operation of the arcuate portion 53b of the spring 53 accurately. Therefore, in the relationship with the first gap t1, the second gap t2 between the central portion 55b of the movable element 55 and the inner peripheral portion 51aa of the through hole 51a of the coil 51 is extremely reduced, and the coil 55 and the spring 53 are brought close to each other, which contributes to the overall miniaturization.

A temperature sensor 51c is attached to the coil 51 to detect the coil temperature during operation. The signal of the detected temperature is input to the control unit to manage the operating temperature of the coil 51.

The coil 51 is housed in the coil fixing portion 49e, and the outer peripheral portion thereof is fixed to the yoke 49 by a resin P. In the embodiment, the upper and lower outer ends of the coil 51 and the outer surface of the mounting bracket 59 are fixed by the resin P. Therefore, in the present embodiment, the coil 51 is indirectly fixed to the yoke 49. However, the coil 51 may be directly fixed to the coil fixing portion 49e of the yoke 49. In the embodiment in which the coil 51 is fixed to the outer surface of the mounting bracket 59, the length of the coil 51 in the X-axis direction is larger than the coil fixing portion 49e, and both ends of the coil 51 in the X-axis direction protrude outward of the opening 59a of the mounting bracket 59. The coil 51 is easily fixed to the outer surface of the mounting bracket 59 by the resin P.

As shown in fig. 4, the movable element 55 is disposed such that the central portion 55b has a uniform second gap t2 with respect to the inner peripheral portion 51aa of the through hole 51a of the coil 51. The equalization of the second gap t2 means that the second gap t2 is formed uniformly in the Z-axis direction between the upper and lower sides of the central portion 55b and the upper and lower sides of the inner peripheral portion 51aa of the through hole 51 a. The upper and lower second gaps t2 are set to a size that allows the central portion 55b of the movable element 55 to swing in relation to the first gap t 1.

When the both end portions 55a of the mover 55 are vibrated in the first gap t1 by switching the energization of the coil 51 in the forward and reverse directions, the center portion 55b of the mover 55 is vibrated in the second gap t2 to vibrate the mover 55 in a seesaw motion.

Before the coil 51 is energized, the movable element 55 is balanced by the yoke 49 supported by the four springs 53, and both end portions 55a maintain the first gap t1 with respect to the front ends 49h, 49i, 49j, and 49k of the yoke 49.

By the energization of the coil 51, both sides of the coil 51, i.e., one of both end portions 55a of the mover 55, become N-poles, and the other becomes S-poles. On the other hand, when the coil 51 is switched between the forward and reverse directions, one of the opposite ends 55a is switched to the S pole, and the other is switched to the N pole.

When the end portion 55a is an N-pole, the current is switched to be repelled from the upper end 49h or end 49j of the yoke 49, which is an N-pole, and attracted to the lower ends 49i and 49k of the yoke 49, which are S-poles. When the end 55a is an S-pole, it is attracted to the upper front end 49h or the front end 49j of the yoke 49, which is an N-pole, and repelled from the lower front ends 49i and 49k of the yoke 49, which are S-poles.

Therefore, the movable element 55 can be rotated to slightly swing by switching the energization of the coil 51 in the forward and backward directions. The degree of oscillatory rotation is controlled by control of the current. That is, the degree of amplitude of the movable element 55 in the first gap t1 is changed by the current to control the engraving depth.

During this swinging rotation, the spring 53 receives a load from the spring seat portion 55c of the movable element 55 and flexes so as to deform the cross section, and when the load from the spring seat portion 55c is released, the spring seat portion 55c is urged so as to restore the cross sectional shape.

Therefore, even with the small-sized spring 53, it is possible to accurately follow the minute swing rotation of the movable element 55, and to bias the minute vibration of the movable element 55.

Further, since the center portion 55b of the mover 55 is swingably rotated within the through hole 51a of the coil 51, the weight of the coil 51 is not related to the minute vibration of the mover 55, and the minute vibration of the mover 55 can be accurately and reliably performed. When the spring 53 is deflected during vibration, the arc-shaped portion 53b is deformed such as to be slightly crushed, and the outer surface thereof protrudes toward the coil 51. At this time, the opening edge 51ab of the coil 51 allows the spring 53 to flex, and the movable element 55 can be vibrated appropriately. Further, since the spring 53 is disposed as close as possible to the central portion 55b of the mover 55, it is easy to achieve both accurate support of the mover 55 by the spring 53 and accurate vibration of the mover 55.

The four springs 53 are symmetrically disposed in an inclined manner, so that the urging force of the springs 53 can be uniformly applied to the arc-shaped portion 53b, and an accurate urging force can be applied to the minute oscillatory vibration.

Such minute vibrations are transmitted to the pin support block 22 and the coupling member 23 via the arm portion 21, and the minute engraving can be reliably performed by vibrating the stylus 13 based on a signal obtained by converting image data into an electric signal.

The second gap t2 is set to a size that allows the swing of the center portion 55b of the mover 55 in relation to the first gap t1, and therefore, the number of turns of the coil 55 can be secured and the size can be reduced as much as possible.

[ example 2 ]

Fig. 15 is a conceptual diagram of two vibration generators. Fig. 16 (a) is a schematic diagram of the resolution of an engraved image by the single solenoid method as a comparative example. Fig. 16 (B) is a schematic diagram of the resolution of the engraved image by the two-solenoid method. Fig. 17 (a) is a schematic diagram of an engraved image by the single solenoid method as a comparative example. Fig. 17 (B) is a schematic diagram of an engraved image by the two-solenoid method. Fig. 18 is a graph showing a distribution map of signals of the addition circuit and the subtraction circuit. Fig. 19 (a) is a graph illustrating a signal diagram. Fig. 19(B) is a graph illustrating an engraving pattern corresponding to the signal pattern.

As shown in fig. 15, example 2 includes two vibration generators 19A and 19B.

One of the two vibration generators 19A, 19B is mounted so as to obtain vibration in the Z-axis direction, and the other is mounted so as to obtain vibration in, for example, the X-axis direction orthogonal to the Z-axis direction.

The above-described one vibration generating device 19A that acquires vibration in the Z-axis direction has the same configuration as the vibration generating device 1 of embodiment 1, and includes a stylus holder 25 configured to be interlocked with the arm portion 21 via a connecting member 23 in the Z-axis direction, and the stylus holder 25 is supported by the distal ends of support springs 27c, 27d that allow vibration in the Z-axis and X-axis directions. As in embodiment 1, the support springs 27c and 27d are arranged so that their base ends are fixed to a fixed block 29 serving as a fixed portion and extend toward the stylus holder 25 in the lateral direction. The stylus 13 is supported by a stylus support 25.

Unlike embodiment 1, the support springs 27c and 27d are formed in a rod shape or the like, and allow vibration in the XZ direction of the stylus holder 25.

The other vibration generating device 19B that acquires vibration in the X axis direction is configured such that the arm portion 21B is interlocked with the stylus holder 25 of the vibration generating device 19A in the X axis direction via the connecting member 23B in the X axis direction. That is, the structure of the vibration generating device 19B up to the coupling member 23B is the same as that of the vibration generating device 19A. However, the material, thickness, and length of the coupling member 23B may be changed according to the horizontal structure of the vibration generating device 19B. The shape, support structure, and the like of the vibration generating device 19B can be changed depending on the horizontal position.

The vibration generators 19A and 19B are connected to a drive circuit 63. The drive circuit 63 is shown conceptually to show the relationship of the image signal 65 to the vibration generating devices 19A, 19B. The image signal 65 is connected to a pair of amplifiers 67a and 67b on the output side. The pair of amplifiers 67a and 67b are connected to the adder 69 and the subtractor 71, respectively. The adder 69 is connected to the coil 51 of the vibration generator 19A via an amplifier 73 a. The subtraction circuit 71 is connected to the coil 51 of the vibration generating device 19B via an amplifier 73B.

Then, the energization of the coil 51 of the one and the other vibration generating devices 19A is switched based on the engraving signal. The stylus 13, which vibrates in the Z-axis direction in conjunction with the vibration of the seesaw movement of the movable element 55 of the one vibration generating device 19A, can engrave the medium to be engraved by the relative movement in the X-axis, Y-axis, and Z-axis directions with respect to the medium to be engraved based on the engraving signal. In contrast to this engravable operation, the vibration generating device 19B applies vibration in the X-axis direction to the stylus holder 25 by vibration of the movable element 55 due to the seesaw movement based on the engraving signal, thereby performing engraving.

High-precision engraving can be performed by the two-solenoid method of the vibration generators 19A and 19B.

The resolution of the engraved image of the single solenoid system using only the vibration generating device 19A is shown in fig. 16 (a), and the resolution of the engraved image of the double solenoid system to which the vibration generating device 19B is added is shown in fig. 16 (B). That is, the resolution in the column direction is doubled from d to d 1.

When the character "World" is engraved by the single solenoid method, it is as shown in fig. 17 (a). When a character "World" is engraved in the above-described two-solenoid system, a high-definition engraved image is obtained in the two-solenoid system as shown in fig. 17 (B).

The mechanism for doubling the resolution using the above-described two-solenoid approach is as follows.

When the single solenoid system using only the vibration generating device 19A is used, the position of the writing needle 13 in the column direction within one dot is engraved on a straight line having a constant position in the row direction in accordance with an engraving signal. That is, the drawing needle 13 engraves while changing the depth on a certain straight line. Therefore, even if there is a variation in the gradation of the image data for each dot, the binarized gradation is expressed at the central position in the row direction of the dot. Therefore, in the image signal generated from the photograph, even if the central value of the gradation in one dot is shifted in the column direction, the single-solenoid-type drawing needle 13 must express the gradation at the central position in the column direction of the dot, and the resolution in the column direction is not equal to or higher than a certain value.

On the other hand, when the two-solenoid system using the vibration generators 19A and 19B is used, the resolution in the column direction can be improved. An example of the black card engraving will be described with reference to fig. 18 and 19.

Fig. 18 shows the distribution of signals in the column direction in one point in relation to engraving. In FIG. 18, 0 to 1 are assigned to a and b. The image data can have a gradation value of 256. The signal column shows the state of the color of the minimum unit of engraving (black to gray to white). The minimum unit is divided into two sections a and b at one point.

a: refers to the upper segment of a signal point. The "black percentage degree" of a is shown by numerical values. 0 means all black and 1 means all white.

b: the lower segment of a signal point. The "degree of black percentage" of b is shown by numerical values. 0 means all black and 2 means all white.

a + b: the "engraving depth" of an engraved point is shown by a numerical value. 0 means no engraving and 2 means the deepest. The vibration generating device 19A operates with respect to the depth.

a-b: the "offset position" of the engraved point is shown numerically. 0 means the center, +1 means the uppermost position, -1 means the lowermost position. The vibration generating device 19B operates with respect to the offset.

Therefore, the engraving shown in fig. 19(B) is performed at each point with respect to the signal of fig. 19 (a). For example, when the upper and lower stages of the signal at one point are both all black (0, 0) (the upper first row in fig. 19 a), neither the engraving nor the offset (0, 0) (the upper first row in fig. 19B). When the signal is all white in the upper section and all black (1, 0) in the lower section of one point (the second column in the upper section of (a) of fig. 19), the engraving depth is 1 and the offset is 1(1, 1). That is, the upper section of a dot is engraved at a depth of 1. Hereinafter, the correspondence relationship between the third upper row and the first to third lower rows in fig. 19 is also the same.

In this way, by operating the addition circuit 69 and the subtraction circuit 71 in anticipation of the variation in the shade of the image data in one point and operating the vibration generators 19A and 19B by signal distribution, the position and engraving depth of the write pointer 13 in one point can be controlled, and the resolution in the column direction can be improved.

Further, when the drawing needle 13 is engraved so that the position changes in the column direction within one point, the range of the point may spread to a neighboring point region in the column direction. In this case, although there is no problem even when the image is engraved in this way, it is also possible to cancel the position change control within one point of the drawing needle 13 so that the range of dots in the column direction does not spread to the adjacent dot region.

As described above, in the two-solenoid system, a finer engraved image can be obtained.