JP2002248728A - Engraving head displacement regulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a displacement regulation of an engraving head to be facilitated by a user himself when the head is replaced with a new one or when the head is age-worn so that its characteristics are changed. SOLUTION: An engraving head displacement regulator disposes the engraving head so as not to contact with a gravure cylinder, inputs a step signal as a test drive signal, and drives the head. The regulator further acquires a time response of a displacement (y) of the head to the step signal in a predetermined sampling frequency, rapid Fourier transforms the time response of the displacement (y), and calculates frequency characteristics of a gain y/A. The regulator calculates a DC gain DC and a natural oscillation frequency ωe of the head from the frequency characteristics of the gain, and regulates a control constant by using them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engraving head displacement adjusting device, and more particularly to an engraving machine used in a gravure engraving machine for producing a concave plate for gravure printing by engraving a plurality of cells on the surface of a gravure cylinder. The present invention relates to a head displacement adjusting device.

[0002]

2. Description of the Related Art A gravure engraving machine is a device that forms a square pyramid-shaped hole called a cell on the surface of a cylindrical gravure cylinder whose surface is copper-plated while rotating the gravure cylinder. The amount of ink inserted into the cell is controlled by the depth and width of the cell, so that the image density is expressed. An engraving head is used to form cells on the cylinder surface. The engraving head is provided with a stylus having a diamond needle (bite) at the tip, and performs engraving by vibrating the stylus in response to a drive signal.

A drive signal applied to a stylus (hereinafter simply referred to as an engraving head) of a solid vibrating element is a signal obtained by superimposing an image signal on a carry signal. The carry signal is a sine wave having a frequency of several kHz and vibrates the stylus with a constant amplitude. The image signal is a step signal, and the depth of the cell is adjusted according to the magnitude of the step signal. By applying such a drive signal to the engraving head, the cell is engraved on the cylinder to a depth corresponding to the density of the image signal.

[0004]

As described above, in the gravure engraving machine, since the density is expressed by the depth of the cell, the magnitude of the image signal applied to the engraving head and the depth of the cell are paired. It is necessary to make one correspondence. However, even if an image signal of the same magnitude is applied, the same stylus displacement does not occur due to variations in the characteristics of the engraving head. Therefore, every time the engraving head is replaced with a new one, the displacement of the engraving head must be adjusted. Even if the engraving head is not replaced, the engraving head may wear over time and its characteristics may change as it is used. Adjustment of the engraving head itself in response to such changes or changes in the engraving head requires specialized knowledge and cannot be easily performed by the user. Therefore, in many cases, the engraving head is used as it is despite the change in characteristics. If the characteristics of the engraving head are so different that it cannot be used as is, a technician from the factory will go on a business trip to make adjustments using measuring instruments or measure the characteristics and redesign or change the program at the factory. There is also. On the other hand, even when a gravure engraving machine is shipped, many man-hours are required to adjust the displacement of the engraving head.

An object of the present invention is to enable the user to easily adjust the displacement of the engraving head when the engraving head is replaced with a new one or when the engraving head has worn over time and its characteristics have changed. That is.

Another object of the present invention is to reduce the number of steps required for adjusting the displacement of an engraving head when shipping a product of a gravure engraving machine.

[0007]

A gravure engraving machine for engraving a surface of a gravure cylinder by driving an engraving head by a drive signal obtained by superimposing an image signal on a carry signal is provided. An engraving head displacement adjusting device includes a driving unit, a test driving signal supplying unit, a displacement detecting unit, a first calculating unit, and a second calculating unit. The drive means receives a drive signal and drives the engraving head according to the drive signal. The test drive signal supply unit supplies a predetermined test drive signal to the drive unit for adjusting the displacement of the engraving head. The displacement detecting means detects a displacement of the engraving head by the test drive signal. First
The calculating means calculates the characteristics of the engraving head from the displacement with respect to the test drive signal. The second calculating means calculates a control constant for driving the engraving head using the characteristics of the engraving head.

In the engraving head displacement adjusting device according to the first aspect, in order to adjust the displacement of the engraving head, a test drive signal is supplied to the driving means to drive the engraving head. The displacement of the engraving head with respect to the test drive signal is detected by the displacement detecting means, and the characteristics of the engraving head are calculated by the first calculating means. The characteristics of the engraving head include, for example, a gain based on the displacement of the engraving head with respect to the DC component of the test drive signal (DC gain) and the natural frequency of the engraving head. Based on these characteristics of the engraving head, a control constant for driving the engraving head is calculated by the second calculating means. For example, the gain of the image signal is determined based on the DC gain, and the frequency for detecting the displacement of the engraving head is determined to a value close to the natural frequency of the engraving head.

According to the engraving head displacement adjusting device of the first aspect, the user himself can easily adjust the displacement of the engraving head. Also, the man-hour for adjusting the displacement of the engraving head can be reduced even at the time of shipping the product.

The engraving head displacement adjusting device according to claim 2 is the engraving head displacement adjusting device according to claim 1,
The test drive signal is a predetermined step signal. Since the step signal includes signals of all frequencies, 1
If the displacement of the engraving head is detected by driving the test signal twice, the characteristics of the engraving head for signals of all frequencies can be calculated.

The engraving head displacement adjusting device according to claim 3 is the engraving head displacement adjusting device according to claim 2,
The displacement detecting means detects the displacement of the engraving head with respect to the test drive signal at a constant sampling cycle.

The engraving head displacement adjusting device according to claim 4 is the engraving head displacement adjusting device according to claim 3,
The characteristics of the engraving head are obtained by Fourier transforming the sampled detection values. By detecting the displacement of the engraving head with respect to the step signal at a constant sampling period, and performing a Fourier transform on the detection result, it is possible to calculate the gain and the natural frequency of the displacement of the engraving head with respect to the signal of each frequency. In this case, it is preferable to use a fast Fourier transform in order to perform a numerical calculation at a high speed.

The engraving head displacement adjusting device according to claim 5 is the engraving head displacement adjusting device according to claim 1,
The test signal is a sine wave for a plurality of frequencies. In this case, it is not necessary to perform numerical calculation by Fourier transform in order to obtain the characteristics of the engraving head for each frequency, and the characteristics of the engraving head can be calculated more accurately. In this case, a sine wave (DC signal) having a frequency of zero is also input in order to obtain a gain (DC gain) based on the displacement of the engraving head with respect to the DC component of the test signal.

The engraving head displacement adjusting device according to claim 6 is the engraving head displacement adjusting device according to claim 5,
The frequency of the sine wave is sequentially changed, and the characteristics of the engraving head are obtained from the displacement of the engraving head at each frequency. Since the characteristics of the engraving head are calculated by sequentially changing the frequency of the sine wave of the test drive signal in order, the characteristics of the engraving head for each frequency can be obtained efficiently.

The engraving head displacement adjusting device according to claim 7 is the engraving head displacement adjusting device according to claim 4 or 6, wherein the first calculating means includes, as characteristics of the engraving head, the engraving head with respect to the DC component of the test drive signal. , And a natural frequency of the engraving head are calculated. The gain for the image signal is adjusted based on the gain of the engraving head for the DC component of the test signal, and the gain of the displacement of the engraving head relative to the drive signal during engraving can be set to a target value. If the frequency of the carry signal is set to a value close to the natural frequency of the engraving head, a large gain of the displacement of the engraving head with respect to the drive signal can be obtained during engraving.

The engraving head displacement adjusting device according to an eighth aspect of the present invention is the engraving head displacement adjusting device according to the seventh aspect, wherein the second calculating means calculates the gain of the image signal based on the calculated gain. In this case, by adjusting the gain of the image signal from the gain of the displacement of the engraving head with respect to the test signal, the gain of the engraving head can be set to a target value during engraving.

In the engraving head displacement adjusting device according to a ninth aspect, in the engraving head displacement adjusting device according to the seventh aspect, the second calculating means sets the sampling frequency at the time of engraving based on the calculated natural frequency. calculate. The frequency of the carry signal is set to a value close to the natural frequency of the engraving head in order to increase the gain of the displacement of the engraving head with respect to the drive signal during engraving. The sampling frequency for detecting the displacement of the engraving head during engraving is adjusted in accordance with setting the carry signal to a value close to the natural frequency of the engraving head. As a result, the engraving head can be accurately controlled during engraving.

The engraving head displacement adjusting device according to claim 10 is the engraving head displacement adjusting device according to claim 7,
The second calculating means calculates a carry signal frequency based on the calculated natural frequency. When the carry signal is set to a value close to the natural frequency of the engraving head, a large gain of the displacement of the engraving head with respect to the drive signal can be obtained during engraving.

An engraving head displacement adjusting device according to an eleventh aspect is the engraving head displacement adjusting device according to any one of the seventh to tenth aspects, wherein the type of the engraving head is determined based on the natural frequency calculated by the first calculating means. Is further provided. In this case, by calculating the natural frequency of the engraving head, the type of the engraving head (compatible with 5 kHz or 10 kHz) can be automatically determined.

According to a twelfth aspect of the present invention, in the engraving head displacement adjusting device according to the eleventh aspect, the second calculating means controls the engraving head based on the type of the engraving head determined by the head determining means. The control constant for driving is calculated. In this case, control constants necessary for controlling the engraving head can be automatically set according to the type of the engraving head.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] [Overall Configuration] FIGS. 1 and 2 show the configuration of a gravure engraving machine having an engraving head displacement adjusting device according to an embodiment of the present invention.
Shown in FIG. 1 is a front view of the gravure engraving machine, and FIG. 2 is a plan view of the gravure engraving machine.

As shown in FIGS. 1 and 2, this gravure engraving machine includes a bed 1, a headstock 2 fixed to the upper surface of the bed 1, and a tailstock 3 arranged opposite to the headstock 2.
And a table 4. The tailstock 3 is movable in the left-right direction along a pair of guide rails 6 fixed to the upper surface of the bed 1. The tailstock 3 is a bed 1
The headstock 2 can be approached or separated from the headstock 2 by a drive mechanism 9 including a motor and a belt provided on the side. The tailstock 3 is provided with a center 12.
The center 12 can be moved up and down by a cylinder 13. The table 4 is movable in the left-right direction along a pair of guide rails 7 arranged on the upper surface of the bed 1. The table 4 is moved along the guide rail 7 by a ball screw 15 arranged between a pair of guide rails and a drive motor 16 for driving the same. Headstock 2
Has a main shaft 10, and the main shaft 10 is configured to be rotated by a driving mechanism 11 including a driving motor, a belt, and the like. In such a configuration, the gravure cylinder 14 is, as shown by a two-dot chain line in FIG.
It is supported between the main shaft 10 and the center 12.

The table 4 is provided with an engraving head 21 movably in the front-rear direction. Further, a pair of guide rails 20 is provided on the upper surface of the table 4, and can be moved in the front-rear direction along the guide rails 20 by a driving mechanism including a ball screw 22 and a driving motor 23.

FIG. 3 is a perspective view of the engraving head 21, and FIG. 4 is an exploded perspective view of the engraving head 21. Engraving head 2
1 is a lower holding plate 211 as shown in FIGS.
, A radiation fin 212, a solid vibration element 213, a stylus 214, and a displacement sensor 217. The radiation fin 212 is fixed to the upper surface of the lower holding plate 211. The radiation fin 212 is a member that cools the solid vibration element 213 by air, and has a through hole 212a formed in the center. The solid vibration element 21 is inserted into the through hole 212a.
3 are buried. The fixed vibration element 213 is an element that vibrates according to an applied electric signal, and is, for example, a piezo element or a magnetostrictive element. The stylus 214 is provided on the upper surface of the radiation fin 212. This stylus 214
Is a base 214a fixed to the radiation fin 212 by screws 215, and a diamond tool 216 as an engraving needle protruding in the horizontal direction from the base 214a and provided on the top surface of the tip.
Is attached to the diaphragm 214b. Displacement sensor 2
17 is provided penetrating the lower holding plate 211.
The distal end of the displacement sensor 217 faces the distal end of the diaphragm 214b at a predetermined interval.

At the upper end of the solid vibration element 213, the diaphragm 2
A steel ball 213a that is in point contact with the lower surface of 14b is provided. The solid vibration element 213 vibrates in the direction of the arrow in FIG. 4 when an engraving signal is given. Accordingly, the diaphragm 214
b vibrates up and down with the connection point with the base 214a as a fulcrum. The displacement sensor 217 detects the vibration position of the tip of the diaphragm 214b, that is, the position of the diamond tool 216 in a non-contact manner. As such a displacement sensor, a capacitance type sensor may be used, an ultrasonic type sensor,
An eddy current sensor or a laser displacement sensor may be used.

[Adjustment of Engraving Head Displacement] FIG. 10 shows the electrical hardware configuration of the gravure engraving machine. The host computer 31 outputs the sub-scanning position x_pos to the dual access memory 33. Host computer 3
1 outputs the main scanning position y_pos and the engraving signal r on which the image signal and the carry signal are superimposed to the dual access memory 33 via the parallel interface 32.
The user can set auto tuning ON / OFF in the host computer 31. When auto tuning is set to ON, displacement adjustment of the engraving head described later is automatically performed. The dual port memory 33 has a DSP (Digital Signal Processor) 34
Is connected, and the DSP 34 reads out and outputs the engraving signal r stored in the dual port memory 33.
After the DSP 34 converts the engraving signal r into a drive signal u, the drive signal u is converted into an analog signal by the D / A converter 35, further power-amplified by the driver amplifier 36, and then given to the solid-state vibrating element 213. . Displacement sensor 21
Reference numeral 7 detects the amount of vibration of the diaphragm 214b. The detection result is amplified by the sensor amplifier 37, the output y of the sensor amplifier 37 is converted into a digital signal by the A / D converter 38, and is fed back to the DSP 34. You. DSP34
When there is a difference between the commanded drive signal u and the fed back vibration amount y of the diaphragm 214b, the engraving signal r
Is corrected so that appropriate engraving is performed.

FIG. 6 shows a control block diagram of the feedback control of the engraving head 21. In the feedback control of the engraving head 21, the engraving signal r is input to the controller K and converted into a drive signal u, as shown in FIG.
Is input to the control target P, and the displacement y is output. Here, the controller K corresponds to the DSP 34, the D / A converter 35, and the driver amplifier 36 in the configuration of FIG. 5, and the control target P corresponds to the engraving head 21. In the engraving head displacement adjusting device according to the present embodiment, a step signal or a sine wave signal is used as a test driving signal in order to know the characteristics of the engraving head 21 instead of the driving signal u generated based on the engraving signal r. Here, first, a case will be described in which the displacement of the engraving head 21 is adjusted using a step signal as a test drive signal. As the test drive signal, an impulse signal, a white noise signal, or the like may be used instead of the step signal.

The control algorithm of the engraving head displacement adjusting device will be described with reference to FIG. When a test drive signal of u = A is input to the control target P as shown in FIG. 7A, the engraving head 21 freely vibrates, and the displacement y vibrates as shown in FIG. Since the step signal is considered to include signals of all frequencies, if the magnitude of each frequency component is examined at the displacement y which is an output for the step signal, a frequency response can be approximately obtained. In particular,
The time change of the displacement y in FIG. 7A is detected at a constant sampling frequency, and the time response of y as shown in FIG. 7B is examined. Here, in order to perform a fast Fourier transform later, 2 ⁿ
The displacement y is sampled. For example, the sampling frequency is set to 100 kHz, and 1024 (2 ¹⁰ ) data are sampled. The frequency response of the gain y / A is calculated by performing a fast Fourier transform on the time response of y (FIG. 7B) created in this manner (FIG. 7).
(C)). Next, the gain for a signal having a frequency of zero (DC component) is calculated as DC gain DC, and the value of the frequency at which the gain is maximum in the frequency characteristics of the gain is calculated as the natural frequency ωe of the engraving head 21. The control constant is determined using the characteristics of the engraving head 21 calculated in this manner. It should be noted that there is substantially no problem if the DC gain DC is calculated from the gain for a signal whose frequency is close to zero. For example, a gain at a frequency of several kHz that is sufficiently low may be used.

FIG. 8 shows a flow for adjusting the displacement of the engraving head 21 using the above-described algorithm. In the displacement adjustment of the engraving head 21 described below, the control gain of the controller K, the gain for the DC component of the drive signal of the engraving head 21 (DC gain), the sampling frequency, and the specific The frequencies are measured in advance, and these are used as the reference control gain kg0 and the reference DC gain D
C0, the reference sampling frequency fn0, and the reference natural frequency ωe0 are set in advance.

When a command to start engraving is issued in step S11, the process proceeds to step S12. In step S12, the auto tuning ON / OFF flag is read from the host computer 31 via the dual access memory 33, and ON or OFF is determined. If the auto tuning ON / OFF flag is ON, step S1
3 and if OFF, the process proceeds to step S19,
The gravure cylinder 14 is engraved by a normal engraving operation.

In step S13, the engraving head 21 is driven by a test drive signal in a state where the engraving head 21 does not contact the gravure cylinder 14. Specifically, D /
A step signal equivalent to 1 V is output from the A converter 35 as a test drive signal, and a 20 V step signal obtained by power-amplifying the output signal is applied to the engraving head 21. Then, the process proceeds to step S14,
The displacement y is sampled 1024 times by the / D converter 38 at a sampling frequency of 100 kHz and stored in the dual access memory 33. Thereafter, the process proceeds to step S15, in which window processing is performed on the stored displacement y, and then fast Fourier transform is performed to create a frequency characteristic of the gain.
Although the window processing is processing for improving the accuracy of the fast Fourier transform, it can be omitted. Thereafter, the process proceeds to step S16, where the gain for the DC component having a frequency of 0 is calculated as the DC gain DC, and the frequency at which the gain is maximum is calculated as the natural frequency ωe of the engraving head 21 from the generated frequency characteristics of the gain. Thereafter, the process proceeds to step S17, and the control constant is adjusted using the calculated DC gain DC and natural frequency ωe. Specifically, the gain kg of the controller K is calculated from the equation (1) based on the DC gain DC, and the sampling frequency fn at the time of engraving is calculated from the equation (2) based on the natural frequency ωe. And the sampling frequency is set to kg and fn. kg = kg0 × DC0 / DC (1) fn = fn0 × ωe / ωe0 (2) Here, kg0 is a reference control gain, and DC0 is a reference DC gain. Further, fn0 is a reference sampling frequency, and ωn0 is a reference natural frequency. DC gain D
When C is larger than the reference DC gain DC0, the reference control gain kg0 is too large.
(<1) multiplied by the reference control gain kg0 to obtain the control gain k
Adjust g to a smaller value. DC gain DC is reference DC gain DC
If it is smaller than 0, the reference control gain kg0 is conversely too small. In this case, DC0 / DC
> 1, which can be multiplied by the reference control gain kg0 to greatly adjust the control gain kg. Sampling frequency f
It is necessary to adjust n according to the frequency of the carry signal that vibrates the engraving head 21 during engraving. As the frequency of the carry signal increases, the frequency at which the engraving head 21 vibrates also increases. Therefore, it is necessary to increase the frequency fn at which the displacement y of the engraving head 21 is sampled to follow the change in the displacement y. Since the frequency of the carry signal is determined by the natural frequency ωe, the sampling frequency fn is determined by Expression (2) so as to be proportional to ωe. In the above description, the control constant is calculated by a mathematical formula. However, the control constant may be selected from a preset table based on the obtained DC gain DC, natural frequency ωe, and the like.

Next, the flow shifts to step s18, where the carry frequency at the time of engraving is set to the natural frequency ωe. To set the frequency of the carry signal during engraving to the natural frequency ωn,
This is because the gain of the displacement y is maximized when the engraving head 21 is vibrated at a frequency near the natural frequency ωe. In addition, a test cut is made on the gravure cylinder 14 by the adjusted engraving head 21 to adjust the engraving density. Thereafter, the process proceeds to step S19, and the gravure cylinder 14 is engraved by a normal engraving operation.

[Second Embodiment] In the above embodiment, the step signal is used as the test drive signal. However, the displacement of the engraving head 21 can be similarly adjusted by using sine wave signals of a plurality of frequencies. In this case, it is not necessary to perform numerical calculation by fast Fourier transform as in the case where a step signal is used as a test drive signal, so that a more accurate frequency characteristic can be obtained.

FIG. 9 shows an algorithm for controlling the engraving head displacement adjusting device when the test drive signal is a sine wave signal.
This will be described with reference to FIG. When a test drive signal of u = Asinωt is input to the control target P as shown in FIG. 9A, the displacement y of the engraving head 21 becomes y = as shown in FIG.
Bsin (ωt + φ). If the ratio A / B of the amplitude A of the test drive signal u and the amplitude B of the displacement y as its output is obtained, the gain for the frequency ω can be obtained. Therefore, by continuously changing (sweeping) the frequency ω of the test drive signal and calculating the gain A / B for each frequency, a gain frequency characteristic as shown in FIG. 9B is obtained. From the frequency characteristics of the gain, a gain for a signal having a frequency of zero (DC component) is calculated as a DC gain DC as in the above-described embodiment, and the value of the frequency at which the gain is the maximum in the frequency characteristics of the gain is determined as the engraving head 21. Is calculated as the natural frequency ωe. The control constant is determined using the characteristics of the engraving head 21 calculated in this manner.

FIG. 10 shows a flow for adjusting the displacement of the engraving head 21 using the above-described algorithm. Also in the displacement adjustment of the engraving head 21 described below, the reference control gain kg0, the reference DC gain DC0, the reference sampling frequency fn0, and the reference natural frequency ωe0, which are measured in advance, are the same as in the above embodiment.

In step S31, it is determined whether or not a command to start engraving has been issued. If the command to start engraving has been issued, the flow proceeds to step S32. In step S32, an auto tuning ON / OFF flag is read from the host computer 31 via the dual access memory 33, and ON or OFF is determined. Auto tuning O
If the N / OFF flag is ON, the process proceeds to step S33. If the N / OFF flag is OFF, the process proceeds to step S40, and the gravure cylinder 14 is engraved by a normal engraving operation.

In step S33, the engraving head 21 is driven by a test drive signal while the engraving head 21 does not contact the gravure cylinder 14. Specifically, D /
A predetermined frequency of 1 V as a test drive signal from the A converter 35
A corresponding sine wave signal is output, and this is
Amplify the power and apply a 20V sine wave signal to the engraving head 2.
Apply to 1. Thereafter, the process proceeds to step S34, in which the gain for this frequency is calculated and the dual access memory 3
3 is stored. Thereafter, the process shifts to step S35 to determine whether or not the sweep of the frequency of the sine wave signal has been completed.
If the sweep has not been completed, the process proceeds to step S36, where the frequency of the sine wave signal is changed.
The processing of steps 3 to 34 is repeated, the gain for each frequency is calculated, and the frequency characteristic of the gain is created. Step S35
If the sweep has ended in step S37,
Move to In step S37, the gain for the DC component at which the frequency becomes zero is calculated as the DC gain DC, and the frequency at which the gain becomes the maximum is calculated as the natural frequency ωe of the engraving head 21 from the frequency characteristics of the created gain. Thereafter, the process proceeds to step S38, and the control constant is adjusted from the equations (1) and (2) using the calculated DC gain DC and the natural frequency ωe in the same manner as in the above embodiment. Next, step S
39, the frequency of the carry signal at the time of engraving is set to the natural frequency ωe, and a test cut is performed on the gravure cylinder 14 to adjust the engraving density. Then, step S40
To the gravure cylinder 14 by a normal engraving operation.
Sculpture.

[Summary] According to the engraving head displacement adjusting device of the first or second embodiment, when the engraving head 21 is replaced with a new one, or when the characteristics of the engraving head 21 change due to aged wear, the user can use the device. , Auto tuning ON
If the / OFF flag is set to ON, the displacement of the engraving head 21 can be easily adjusted. In addition, the displacement of the engraving head 21 can be automatically adjusted even at the time of product shipment, and the number of steps can be reduced.

In the above embodiment, the natural frequency ωe of the engraving head 21 is calculated, and the type of the engraving head 21 (for example, 5 kHz or 10 kHz) is calculated from the natural frequency ωe.
Hz). Using this determination result, each control constant can be automatically set to a control constant corresponding to the type of the engraving head 21. Therefore, the type of the engraving head 21 (for example, corresponding to 5 kHz or 10 kHz
Even if z correspondence is unknown, the displacement of the engraving head 21 can be easily adjusted.

[0040]

According to the present invention, the user can easily adjust the displacement of the engraving head when the engraving head is replaced with a new one or when the engraving head wears over time and the characteristics change. In addition, the displacement of the engraving head can be automatically adjusted even when the product is shipped, and the number of steps can be reduced.

Further, according to the present invention, even if the type of engraving head (for example, 5 kHz or 10 kHz) is unknown, the displacement of the engraving head can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a front view of a gravure engraving machine including an engraving head displacement adjusting device according to an embodiment of the present invention.

FIG. 2 is a plan view thereof.

FIG. 3 is a perspective view of an engraving head.

FIG. 4 is an exploded perspective view thereof.

FIG. 5 is a hardware configuration of an engraving head displacement adjusting device according to an embodiment of the present invention.

FIG. 6 is a control block diagram of the engraving head.

FIG. 7 is an algorithm (step signal) for adjusting the displacement of the engraving head.

FIG. 8 is a flow (step signal) of displacement adjustment of the engraving head.

FIG. 9 is an algorithm (sine wave signal) for adjusting the displacement of the engraving head.

FIG. 10 is a flowchart (sine wave signal) of engraving head displacement adjustment.

[Explanation of symbols]

 21 Engraving Head 213 Solid Vibration Element 214 Stylus 217 Sensor 31 Host Computer 32 Parallel Interface 33 Dual Access Memory 34 DSP 35 D / A Converter 36 Driver Amplifier 37 Sensor Amplifier 38 A / D Converter

Claims (12)

[Claims] An engraving head displacement adjusting device of a gravure engraving machine for engraving a surface of a gravure cylinder by driving an engraving head by a drive signal obtained by superimposing an image signal on a carry signal, wherein the engraving head is driven. A driving unit, a test driving signal supplying unit that supplies a predetermined test driving signal to the driving unit, a displacement detecting unit that detects a displacement of the engraving head according to the test driving signal, and the displacement from the displacement with respect to the test driving signal. An engraving head displacement adjusting device, comprising: first calculating means for calculating characteristics of an engraving head; and second calculating means for calculating a control constant for driving the engraving head using the characteristics of the engraving head. 2. The apparatus according to claim 1, wherein the test drive signal is a predetermined step signal. 3. The engraving head displacement adjusting device according to claim 2, wherein said displacement detecting means detects a displacement of the engraving head with respect to said test drive signal at a constant sampling cycle. 4. The apparatus according to claim 3, wherein the characteristics of the engraving head are obtained by performing a Fourier transform on the sampled detection values. 5. The apparatus according to claim 1, wherein the test signal is a sine wave for a plurality of frequencies. 6. The engraving head displacement adjusting device according to claim 5, wherein the frequency of the sine wave is sequentially changed, and the characteristics of the engraving head are obtained from the displacement of the engraving head at each frequency. 7. The engraving head calculates, as characteristics of the engraving head, a gain based on a displacement of the engraving head with respect to a DC component of the test drive signal and a natural frequency of the engraving head. The engraving head displacement adjusting device according to 4 or 6. 8. The apparatus according to claim 7, wherein said second calculating means calculates a gain of said image signal based on said calculated gain.
A displacement adjusting device for an engraving head according to item 1. 9. The engraving head displacement adjusting device according to claim 7, wherein said second calculating means calculates a sampling frequency at the time of engraving based on said calculated natural frequency. 10. The engraving head displacement adjusting device according to claim 7, wherein said second calculating means calculates a carry signal frequency based on said calculated natural frequency. 11. The engraving head displacement adjusting device according to claim 7, further comprising a head determining unit that determines a type of the engraving head based on the natural frequency calculated by the first calculating unit. 12. The engraving head displacement according to claim 11, wherein said second calculating means calculates a control constant for driving said engraving head based on the type of engraving head determined by said head determining means. Adjustment device.