JPH1142757A - Stylus gap measuring apparatus for gravure engraving machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and accurately measure a gap amount of styluses by obtaining a width of cells and a width of channels formed between adjacent two cells from image information, and calculating the gap amount from these data. SOLUTION: In the case of measuring a gap amount, density data (d) so that a shift amount of a stylus becomes equivalent to a displacement amount by the density data is obtained (S10). A test-engraving is executed by using the data (d) in a manual mode (S10). A size of a cell formed by the test- engraving is actually measured (S12). A virtual channel width W2 is calculated based on a cell width W1 and cell length 1 (S13). A gap amount S is obtained from the width W1 obtained by the actual measurement and the width W2 (S14). A gap amount S obtained by converting into the cell width is converted into an actual gap amount (S) by using a value of an angel of a cutting edge of the stylus (S15).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a gravure engraving machine,
In particular, the present invention relates to a stylus gap measuring device of a gravure engraving machine for measuring a gap amount between a tip of a shoe that contacts a surface of a gravure cylinder and a stylus for engraving the gravure cylinder.

[0002]

2. Description of the Related Art A gravure engraving machine is a device for forming a small 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.
Engraving is performed by vibrating at the frequency of z.

FIG. 12 shows a signal waveform applied to an engraving head, which corresponds to a displacement waveform of Stalice. This signal is obtained by superimposing a high-frequency carry signal (carrier signal) as shown in FIG. 12A) and a density signal (density data) as shown in FIG. 12B. By applying such a signal (engraving signal) to the engraving head, a cell having a depth and a width corresponding to the density data can be engraved on the cylinder surface. FIG.
The dashed line S in 2 (c) corresponds to the cylinder surface, and the portion shown by the hatched area in the figure corresponds to the cell.

In such a gravure engraving machine, a shoe is provided on the side of the engraving head so as to be in contact with the surface of the gravure cylinder in order to make the amount of engraving for the engraving signal constant.
By pressing the shoe tip against the gravure cylinder, the stylus and the surface of the gravure cylinder can always be kept at a constant distance, and the same engraving amount can be obtained for the same engraving signal.

In order to effectively use the displacement of the stylus, it is preferable that the distance between the stylus and the surface of the gravure cylinder (gap amount; sometimes simply referred to as the stylus gap amount) is small. On the other hand, if there is no gap amount, extra engraving may be performed due to overshoot of the stylus. Therefore, the gap amount is usually set to about 2 to 4 μm.

[0006]

When the stylus is replaced, it is necessary to adjust the stylus gap. Conventional adjustment of the gap amount is performed while observing the stylus and the shoe with an optical microscope. However, as described above, the gap amount is very small, on the order of a few μm, and the stylus or shoe is not a planar one but a three-dimensional object, so focusing with a microscope is difficult, and the gap amount is measured accurately. And it is difficult to adjust. Further, the tip of the shoe may be a convex spherical surface, in which case an error is likely to occur during observation with a microscope, making the measurement more difficult.

An object of the present invention is to make it possible to measure the stylus gap amount easily and accurately.

[0008]

A stylus gap measuring device for a gravure engraving machine according to claim 1 engraves a shoe and a gravure cylinder in contact with a surface of a gravure cylinder based on an engraving signal corresponding to image density data. An apparatus for measuring a gap amount between the stylus and the stylus,
A cell observation unit, an image processing unit, and a gap amount calculation unit are provided. The cell observation means obtains, as image information, a cell shape corresponding to predetermined density data formed in advance on the cylinder surface by the stylus. The image processing means obtains the cell width of the cell and the channel width of a channel formed between two cells adjacent in the main scanning direction from the image information obtained by the cell observation means. The gap amount calculating means calculates the gap amount from the data of the cell width and the channel width obtained by the image processing means.

In this apparatus, the cells formed in the gravure cylinder are observed by the cell observation means by the engraving signal corresponding to the predetermined density data, and the image information of the cells is obtained. The cell width and the channel width are obtained by the image processing means based on the image information. Then, the gap amount is calculated from the data of the cell width and the channel width obtained by the image processing means.

In this case, it is possible to calculate the gap amount only by forming a cell corresponding to the predetermined density data and measuring it. This eliminates the need for a manual measurement operation using an optical microscope as in the related art, and the gap amount can be easily obtained. In addition, it is possible to eliminate individual differences among workers to be measured, and to always obtain accurate values.

According to a second aspect of the present invention, there is provided a stylus gap measuring device for a gravure engraving machine, wherein the stylus is shifted in a direction away from the gravure cylinder by a predetermined shift amount. The gap amount is calculated from the data of the cell width and the channel width of the cell formed by the engraving signal corresponding to the density data in which the amount and the displacement amount by the density data become the same.

In this apparatus, cells are formed by engraving signals corresponding to density data in which the stylus shift amount and the displacement amount based on the density data have the same magnitude. Here, when the stylus is driven by an engraving signal corresponding to the density data in which the amount of shift of the stylus and the amount of displacement by the density data are the same, in this state, the position (displacement) of the stylus amplitude center is the stylus and the shoe. Is equal to the gap amount. Then, the position of the center of the amplitude of the stylus can be obtained by calculation using the cell width and the channel width. Therefore, by calculating the cell width and the channel width in the above state, the gap amount can be obtained by calculation.

A stylus gap measuring device for a gravure engraving machine according to a third aspect is the device according to the second aspect, wherein the gap amount calculating means calculates a cell width corresponding to the gap amount from data of the cell width and the channel width. The cell width corresponding to this gap amount is converted into a gap amount as a displacement using the value of the stylus edge angle. What can be actually measured using the cell observation means and the image processing means is a cell width, a cell length, or a channel width of a cell having a planar shape appearing on the surface of the gravure cylinder. Then, it is difficult to measure the displacement (depth of the cell) of the stylus in the direction intersecting the rotation axis of the gravure cylinder. So in this device,
First, the cell width corresponding to the gap amount to be obtained is obtained from the actually measured data obtained by the cell observation means and the image processing means. Then, the relationship between the depth (displacement) of the cell formed thereby and the cell width can be determined from the angle of the cutting edge of the stylus, so that the cell width determined above is converted into the gap amount.

Here, since the displacement of the stylus corresponding to the gap amount is obtained from the planar shape of the cell formed in the gravure cylinder, the processing is easy. A stylus gap measuring device for a gravure engraving machine according to claim 4 is the device according to any one of claims 1 to 3, wherein the image processing means calculates a channel width from a cell width and a cell length of the formed cell.

As described above, when a cell is formed by an engraving signal corresponding to density data in which the stylus shift amount and the displacement amount based on the density data are the same, a channel is not generally formed. That is, each cell is formed independently, and an unengraved portion remains between cells adjacent in the main scanning direction. Therefore, in this case, the channel width cannot be measured by the cell observation means or the image processing means. Therefore, in this apparatus, a virtual channel width is calculated from the cell width and the cell length, and the gap amount is obtained from the obtained channel width and the cell width.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

[Overall Configuration] FIGS. 1 and 2 show a gravure engraving machine employing an embodiment of the present invention. This gravure engraving machine
A bed 1, a headstock 2 fixed to the upper surface of the bed 1,
A tailstock 3 is provided facing the headstock 2, and a first table 4 and a second table 5 are provided. Tailstock 3
Is a pair of guide rails 6 arranged on the upper surface of the bed 1.
Along the right and left direction of the apparatus. The tailstock 3 can be moved toward or away from the headstock 2 by a drive mechanism 9 including a motor and a belt provided on the bed side. In addition, the center 12 of the tailstock 3 can be freely protruded and retracted by the cylinder 13. First table 4
The second table 5 is movable in the left-right direction along a pair of guide rails 7 arranged on the upper surface of the bed 1.
Each of the tables 4 and 5 is movable along the rail 7 by a ball screw 15 disposed between the pair of rails 7 and a drive motor 16 for driving the ball screw. The spindle 10 of the headstock 2 has a drive mechanism 11 including a drive motor and a belt.
Is to be rotated. In such a configuration, the gravure cylinder C is supported between the main shaft 10 and the center 12, as shown by a two-dot chain line in FIG.

An engraving head 21 is provided on the first and second tables 4 and 5 so as to be movable in the front-rear direction of the apparatus.
A guide rail 20 is provided on the upper surface of the first table 4, and the engraving head 21 is moved by a driving mechanism including a ball screw 22 and a driving motor 23. [Stylus and its driving mechanism] FIG.
1 shows a stylus provided in the apparatus 1 and a driving mechanism thereof.

The stylus 30 is fixed to the tip of a torsion shaft 31, and one end of the stylus 30 is provided with a diamond cutting tool 32. The other end of the torsion shaft 31 is fixed to a fixing portion 33. Also twist shaft 3
A rotor 34 having a diamond shape in a plan view is fixed to an intermediate portion 1. A laminated magnetic body (stator) 35 is arranged around the rotor 34 so as to sandwich the rotor 34, and a permanent magnet 36 for applying a magnetic force to the stator 35 is arranged on a side of the stator 35. A coil 37 is provided between the rotor 34 and the stator 35 around the rotor 34.
Is arranged. In such a configuration, by applying an engraving signal to the coil 37, the stylus 30 vibrates in the direction of the arrow in the figure according to the frequency of the engraving signal.

As schematically shown in FIG. 4, the engraving head 21 is provided with a shoe 39 whose tip abuts on the surface of the gravure cylinder C. And shoe 39
Is pressed against the surface of the gravure cylinder C, the tip of the cutting tool 32 of the stylus 30 and the gravure cylinder C
A predetermined gap amount s is ensured between the first and second surfaces. FIG. 4 schematically shows each part, which is different from the actual dimensional relationship. Usually, the gap amount s is set to about several μm as described above.

[Control Block] FIG. 5 shows a control block of the present apparatus. This apparatus has a controller 40 including a microcomputer including a CPU, a RAM, a ROM, and the like. Further, an optical microscope 41 for observing the shape of a cell formed on the surface of the gravure cylinder C facing the surface near the side end of the gravure cylinder C disposed between the headstock 2 and the tailstock 3 is provided. Are located. Optical microscope 41
Is movable toward or away from the gravure cylinder C. The optical microscope 41 has a fiber cable 42.
The strobe light source 43 is connected via the. Further, a strobe power source 44 is connected to the strobe light source 43.
By causing the strobe light to be emitted at a predetermined frequency by the strobe light source 43, it is possible to observe one location on the cylinder surface as a still image while rotating the gravure cylinder C. The optical microscope 41 is provided with a CCD 45. Image information obtained by the CCD 45 is input to a camera controller 46. The camera controller 46 is connected to the image processing device 47.

A CRT monitor 48 is connected to the image processing device 47. A video signal is input from the camera controller 46 to the image processing device 47, and the image processing device 47
, A monitor signal is sent to the CRT monitor 48. The image processing device 47 is a device for calculating a cell shape based on a video signal from the camera controller 46. The image processing device 47 and the controller 40
They are connected to each other via 232C.

The controller 40 includes a CPU, a RAM, an R
The microcomputer includes a microcomputer having an OM or the like, and has a function of calculating a stylus gap amount based on data from the image processing device 47 or adjusting an engraving signal. The engraving signal output from the controller 40 is provided to the engraving head 21 via the drive amplifier 49. In the engraving head 21, an engraving signal from the drive amplifier 49 is supplied to the coil 37. The rotational position of the cylinder C is detected by an encoder 50, and an output signal of the encoder 50 is input to the controller 40. Further, the controller 40 sends a timing pulse to the camera controller 46, and the camera controller 46 sends a strobe timing signal to the strobe power supply 44 to emit a strobe. The controller 40
Is connected to another input / output unit.

[Basic Concept of Gap Amount Measurement] The basic feature of the configuration of the present invention is that the shape of the cell formed in the gravure cylinder C is measured using an optical microscope or the like, and is obtained from data on the shape of the cell. The point is to calculate the gap amount between the stylus and the shoe tip (gravure cylinder surface). At this time, the relationship between the cell shape and the gap amount is used. The relationship will be described with reference to FIGS.

First, the engraving signal Es generated by the controller 40 is represented by the following equation. FIG. 12 shows the basic concept of the engraving signal itself. Es = Dc · Gc + Di · Gi + Go where Dc: carrier signal (carry signal) Di: density data (density signal) Gc: carrier wave (carry) gain Gi: density gain Go: shift gain When a carrier signal in this engraving signal is applied 6 and 7 schematically show the displacement of the stylus with respect to the gravure cylinder C (however, converted into the cell width). In the figure, the displacement of the stylus due to the carrier signal is a sine wave having a predetermined amplitude, and the density data Di
The center of the amplitude moves on the straight line m according to the gradation of.
In a free state in which no engraving signal is applied to the engraving head, the stylus is separated from the surface of the gravure cylinder by a predetermined gap amount s, as shown in FIG. When the value obtained by converting the gap amount s into the cell width is represented by “S”, it is represented as shown in FIG. Here, in FIG. 6, the amount of displacement of the stylus is all converted into the cell width of the cell formed by the stylus at that displacement. Hereinafter, the term “displacement amount” is a value obtained by converting the actual displacement amount into a cell width, and if not converted, is referred to as the “actual displacement amount”.

In a state where the stylus is separated from the gravure cylinder C by the gap amount S, when the density data is "0", the stylus is further moved so that the stylus is separated from the gravure cylinder C by the displacement amount O. Is shifting. This displacement amount O is obtained as a result of shifting by the shift gain Go. Then, for example, at the density P%, the stylus is displaced by the displacement amount Q (including the shift amount) obtained by multiplying the density data Di corresponding to the density P% by the density gain Gi, and vibrates around this position. The maximum value W1 of the stylus displacement in this case
Corresponds to the cell width of the cell formed based on the image data of the density P%, and the minimum value W2 corresponds to the channel width of the channel formed between the cells adjacent in the main scanning direction. The center of amplitude of the displacement of the stylus is (W1 + W2) / 2.

Here, considering a case where the shifted displacement amount O and the displacement amount Q based on the density data Di when the density data Di is the predetermined value d are the same, FIG.
As shown in (1), the center of amplitude of the displacement of the stylus matches the displacement amount corresponding to the gap amount. That is, for the density data Di = d, S = (W1 + W2) / 2.

As is apparent from the above description, the engraving signal generated based on the density data d such that the stylus shift displacement amount O and the density data displacement amount Q become equal to each other is applied to the engraving head to change the stylus. The engraving signal is driven, the cell width W1 of the cell formed thereby and the channel width W2 of the channel are measured, and the amplitude center (W1 + W) of the engraving signal is measured.
If 2) / 2 is obtained, the gap amount S (converted to the cell width) can be obtained. Since the relationship between the actual displacement amount s (gap amount) and the cell width is obtained from the stylus edge angle, the actual gap amount s is obtained if the cell width converted gap amount S is obtained as described above. be able to.

The density data d under the above conditions
Is determined as d = Go / Gi from d · Gi = Go, assuming that the product of the density data d and the density gain Gi is equal to the shift gain Go. In addition, when a cell is formed with such density data d, a channel is not generally formed. Therefore, a virtual channel width (negative channel width) is obtained from the cell width and the cell length by calculation, and a gap amount is obtained from the channel width and a cell width obtained by actual measurement.

[Control Process] Based on the above concept, the present apparatus performs a control process as shown in FIGS. 8 and 9 to obtain the actual gap amount s. In the flowchart shown in FIG. 8, when the start switch of the apparatus is turned on, first, in step S1, initialization is performed. In this initial setting, processing such as moving each unit to an initial position is performed. Next, in step S2, it is determined whether or not the gap amount measurement mode has been selected. The gap amount measurement mode is
This mode is selected when the stylus is replaced, for example, and the gap amount, which is the distance between the stylus and the tip of the shoe, is automatically calculated according to the basic principle described above.
In step S3, it is determined whether the cell monitor mode has been selected. This cell monitor mode is a mode for performing engraving on a gravure cylinder on a trial basis and adjusting the displacement of the stylus, that is, the cell depth. In step S4, it is determined whether an engraving start command has been issued.

When the gap amount measurement mode is selected, the program shifts from step S2 to step S5, and executes a gap amount measurement process in step S5. If the cell monitor mode has been selected, the process proceeds from step S3 to step S6 to execute stylus displacement adjustment processing. If the start of engraving is selected, the process moves from step S4 to step S7. In step S7, an engraving process is performed on the surface of the gravure cylinder according to the image information.

Next, the gap amount measuring process will be described. In step S10 in FIG. 9, density data d is obtained such that the stylus shift amount is equal to the displacement amount based on the density data. As described above, the density data d is obtained by d = Go / Gi. In this case, the shift gain Go and the density gain Gi are set to the values set up to that time, that is, for example, when the stylus is changed. When performing stylus, the value before changing the stylus is used. The Go and Gi gains may have any values as long as the size of the cell to be formed can be measured.

Next, in step S11, test engraving is performed using the density data d in the manual mode. Step S
At 12, the size (cell width W1 and cell length 1) of the cell formed by the test engraving is actually measured. In actual measurement of this cell, first, a control signal is sent to the camera controller 46 to focus the optical microscope 41 on the cylinder surface. Further, a timing pulse is transmitted to the camera controller 46 in accordance with the number of rotations of the gravure cylinder C and the number of lines of the cell to be engraved, and the strobe light is emitted at that timing. This makes it possible to observe the cell shape at a predetermined position engraved on the gravure cylinder C by the optical microscope 41. When the optical microscope 41 is focused on the cylinder surface, a density histogram of the cell image captured by the CCD 45 is created, and the optical microscope 41 is moved forward or backward until a maximum contrast is obtained. The position of the optical microscope at which the maximum contrast is obtained is the focus position. Such control is performed by the image processing device 47. Note that the above-described auto focus may be performed using a distance sensor that measures the distance to the cylinder surface.

The cell-shaped image data thus obtained is sent from the camera controller 46 to the image processing device 47 as a video signal, and is created by A / D conversion. Then, the image processing device 47 measures the cell width W1 and the cell length l. The measurement data of this cell size is
The data is taken into the controller 40 via the RS232C.

When measuring an engraved cell,
For example, 10 cells in the latter half of the plurality of engraved cells are measured, and the average value of the cell width and the cell length is obtained. The reason for measuring the latter half of the plurality of engraved cells is to measure cells formed in a state where the engraving is stable. When cells are formed based on the density data d, generally, as shown in FIG. 10, adjacent cells in the main scanning direction are not continuous, and no channel is formed.
Therefore, in step S13, the virtual channel width W
2 is calculated based on the cell width W1 and the cell length 1 obtained in step S12. As shown in FIG.
The angle corresponding to the end of the cell at the phase of the carrier is θ
(Radian) and the pitch of the cells in the main scanning direction is L (specified value), then θ = (π / 2) + (l · π) / L. Then, the channel width W2 is obtained as W2 = W1 (sin θ + 1) / (sin θ−1).

Next, in step S14, a gap amount S is obtained from the cell width W1 obtained by actual measurement and the channel width W2 obtained by the calculation in step S13. As described above, the gap amount S can be obtained as S = (W1 + W2) / 2.

Here, as described above, the gap amount S is obtained by converting the actual gap amount s into a cell width. Therefore, in step S15, the gap amount S obtained by converting into the cell width is calculated using the value of the angle of the cutting edge of the stylus.
It is converted to the actual gap amount s. As shown in FIG.
Assuming that the cutting edge angle of the stylus is φ (degrees), the cell width is W, and the cell depth (displacement) is D, then D = W · tan {π (180−φ) / 360} / 2. Therefore, the relationship between the gap width S in terms of the cell width and the actual gap amount (displacement) s is as follows: s = S · tan {π (180−φ) / 360} / 2. s can be determined.

Using the gap amount s obtained in this way, the cell depth adjustment processing in step S6 is performed, but the detailed description of step S6 is omitted here. As described above, in this embodiment, test engraving is performed using the density data d, and the gap amount is obtained by calculation. Therefore, the work for measuring the gap amount becomes much easier than before, and the measurement can be performed with high accuracy.

[0038]

As described above, according to the present invention, the gap amount between the stylus and the tip of the shoe can be measured easily and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a front view of a gravure engraving machine employing one embodiment of the present invention.

FIG. 2 is a plan view thereof.

FIG. 3 is a perspective view showing a stylus provided on the engraving head and a driving mechanism thereof.

FIG. 4 is a schematic diagram showing a gap amount between a stylus and a shoe.

FIG. 5 is a control block diagram of the present apparatus.

FIG. 6 is a view for explaining the basic principle of gap amount measurement of the present apparatus.

FIG. 7 is a view for explaining the basic principle of gap amount measurement of the present apparatus.

FIG. 8 is a control flowchart of the present apparatus.

FIG. 9 is a flowchart of a gap amount measurement process.

FIG. 10 is a diagram showing a relationship between a cell and a carrier when a channel width is obtained.

FIG. 11 is a diagram showing the relationship between the blade edge angle of a stylus and the width and depth of a cell.

FIG. 12 is a waveform diagram of an engraving signal.

[Explanation of symbols]

 C Gravure cylinder 21 Engraving head 30 Stylus 40 Controller 41 Optical microscope 45 CCD 46 Camera controller 47 Image processing device

Claims (4)

[Claims] 1. A stylus gap measuring device for a gravure engraving machine for measuring a gap amount between a shoe contacting a surface of a gravure cylinder and a stylus engraving the gravure cylinder based on an engraving signal corresponding to density data of an image. Cell observation means for obtaining, as image information, a shape of a cell corresponding to predetermined density data formed in advance on the cylinder surface by the stylus, and a cell of the cell from the image information obtained by the cell observation means Image processing means for determining a width and a channel width of a channel formed between two cells adjacent in the main scanning direction; and calculating the gap amount from data of the cell width and the channel width obtained by the image processing means. A stylus gap measuring device for a gravure engraving machine, comprising: a gap amount calculating means. 2. The apparatus according to claim 1, wherein the stylus is shifted in a direction away from the gravure cylinder by a predetermined shift amount. 2. The gap amount is calculated from data of a cell width and a channel width of a cell formed by an engraving signal corresponding to (1).
A stylus gap measuring device for a gravure engraving machine according to the above item. 3. The gap amount calculating means calculates a cell width corresponding to the gap amount from the data of the cell width and the channel width, and calculates a cell width corresponding to the gap amount as a value of a cutting edge angle of the stylus. The stylus gap measuring device for a gravure engraving machine according to claim 2, wherein the stylus gap measuring device is used to convert to a gap amount as displacement. 4. The apparatus according to claim 1, wherein said image processing means calculates a channel width from a cell width and a cell length of the formed cell.
The stylus gap measuring device for a gravure engraving machine according to any one of claims 1 to 3.