JPH0938789A - Laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to form longitudinal perforations, longitudinal slits, etc., on continuous paper by laser pulses. SOLUTION: The continuous paper 10 is transported by a tractor 22. A rotary encoder 24 generates 240 pulses at each one inch of the paper 10. A pulse generating circuit 30 generates the pulses in the same period as the output pulses of the encoder 24. A controller 28 widens the width of the pulses generated by this pulse generating circuit 30 by as much as the slower speed component when the feed speed of the paper 10 is slower than the target speed. A controller 28 controls the opening and closing of a gate circuit 32 according to paper processing information. The output pulses of the circuit 30 are impressed via a gate circuit 32 on a laser oscillator 34 which oscillates the pulses. The output laser pulses of the laser oscillator 34 are cast to the regulated position in the transverse direction of the paper 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus, and more particularly to a laser processing apparatus for processing a relatively moving sheet with a laser beam in its moving direction.

[0002]

2. Description of the Related Art A conventional processing device for forming vertical perforations, vertical slits, half slits, etc. on continuous paper rotates a slit blade or vertical sewing machine blade suitable for the processing size in synchronization with the feed speed of continuous paper. It is driven to form vertical perforations of a desired size on continuous paper. To change the machining size, replace it with a slit blade or vertical sewing machine blade that matches the new machining size. If the blade becomes poorly cut, it will be replaced with a new blade.

In such mechanical processing, not only paper dust is generated during processing, but also burrs are generated on the processed surface, which causes printing stains during printing.

On the other hand, there has been proposed a laser processing apparatus which performs non-contact processing with a laser beam. For example, regarding vertical perforations, 1994 Patent Application Publication No. 65
No. 479, page 3, right column, line 30 onward. According to such laser processing, not only paper dust is not generated, but also the processed surface is smooth and burrs are eliminated. Eliminating the trouble of exchanging the slit blade and vertical sewing machine blade is also unnecessary.

[0005]

However, in the configuration described in the above publication, the size of the vertical perforation is the irradiation lens 7.
Is defined by, every time the machining size is changed,
It is troublesome because the irradiation lens 7 that fits the new processing size must be installed. The processing size that can be selected is limited depending on the optical performance of the irradiation lens 7. For example, it is impossible to form a long slit with the configuration described in the above publication.

An object of the present invention is to provide a laser processing apparatus which can flexibly cope with a change in processing size.

Further, the paper feeding speed is not always constant. For example, the speed is initially low, and the speed is gradually increased to stabilize at the initial target speed. Therefore,
It is desired that not only the processing at the target speed but also the speed lower than the target speed, and further, the processing at the desired size can be performed even when the acceleration / deceleration is performed.

Therefore, an object of the present invention is to provide a laser processing apparatus capable of processing a desired size even at different sheet feeding speeds.

[0009]

The moving speed detecting means or the speed detecting means detects the feed speed of the object to be processed.
Depending on the detected movement amount or feed speed, the width and / or the period of the drive pulse of the laser oscillation means is adjusted to make the spot constant when it is desired to form a slit longer than the size of the laser beam spot. The above will be duplicated. As a result, the machined end face becomes smoothly continuous.

Specifically, the cycle of the drive pulse of the laser oscillating means is made inversely proportional to the paper feed speed, and the pulse width of the drive pulse is made wider as the paper feed speed becomes slower.

The processing length can be selected by turning on / off the drive pulse to the laser oscillation means. Therefore, it is possible to cope with any processing size or processing pattern.

[0012]

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

FIG. 1 shows a schematic block diagram of an embodiment of the present invention, and FIG. 2 shows a plan view of a continuous sheet to be processed. The continuous paper 10 is, as shown in FIG.
A large number of feed holes 12 for feeding paper are provided. Lateral perforations 14 that are folded and cut at regular intervals in the longitudinal direction are formed by another processing device. This horizontal perforation for folding and cutting 14
The sheet 10a separated by is the basic unit for vertical perforation processing and printing.

FIG. 1 will be described. The continuous paper 10 is continuously conveyed leftward in FIG. 1 by the tractor device 22 while being guided by the pair of guide rollers 20, 20. The tractor device 22 has a feed hole 1 for the continuous paper 10.
It is equipped with a tractor pin (not shown) engaging with 2, and rotates to convey the continuous paper 10 at a desired speed. A rotary encoder 24 is fixed to the rotary shaft of the tractor device 22. The rotary encoder 24 according to the present embodiment is configured to provide 2 units for 1 inch feeding of the continuous paper 10.
Generate 40 pulses. Paper processing unit is usually 1
/ 3 inch, 1/6 inch, 1/8 inch or 1/10
Since it is an inch, the rotary encoder 24 that generates 240 pulses per inch can easily support such a processing unit.

The paper edge detection device 26 detects the edge of the paper 10a which is the basis of vertical perforation processing. The sheet edge detection device 26 may be, for example, a part of a processing device that forms the horizontal perforations 14, or may be a single device that optically or mechanically detects the formed horizontal perforations.

The output of the rotary encoder 24 and the output of the paper edge detecting device 26 are applied to the control device 28.
The control device 28 comprises a so-called personal computer or its expansion board, and paper processing information is set from a keyboard or other input device. Paper processing information is paper 1
0a includes a machining start position, a machining end position, and machining pattern information. The processing pattern information is, for example, information on the basic periodic pattern of the cut length and the tie length, and by this, an arbitrary vertical cut pattern can be set.

It is obvious that the paper processing information that can be set in the control device 28 is not limited to one in the longitudinal direction of the continuous paper 10. It is also apparent that if the laser beam can be applied to different positions in the lateral direction of the continuous paper 10, lateral position information indicating which position in the lateral direction of the continuous paper 10 to perform laser processing is also required.

The control device 28 includes a rotary encoder 2
A counter 28a for counting the number of output pulses of 4 is provided, and the counter 28a is cleared by the paper edge detection pulse of the paper edge detection device 26. The paper edge detection pulse of the paper edge detection device 26 is detected by the paper edge detection device 2.
The time is adjusted by an amount corresponding to the distance difference between the installation position of 6 and the laser processing position. The count value of the counter 28a is
The present position on the sheet 10a as the processing unit is shown.

The controller 28 also has a period measuring circuit 28 for measuring the period of the output pulse of the rotary encoder 24.
b. Since the output of the rotary encoder 24 is 240 pulses for 1 inch of the continuous paper 10, the paper feed speed v of the continuous paper 10 can be known from the measurement result of the cycle measuring circuit 28b. Although details will be described later, in this embodiment, the laser
Adjust the duration of the pulse. The conversion circuit 28c converts the measurement result of the period measurement circuit 28b into a pulse width control signal based on the correspondence measured in advance. The pulse width control signal is, for example, a signal indicating the pulse width obtained by correcting the reference pulse width at the reference paper feed speed based on the principle described below. If necessary, information on the reference pulse width (which is changed according to the paper thickness) at the reference paper feed speed is set in the conversion circuit 28c.

The controller 28 further comprises a main control circuit 28d for controlling the application of laser pulses to the continuous paper 10 according to the set paper processing conditions. Main control circuit 28
In d, the reference pulse width at the reference paper feed speed set by the user is set in the conversion circuit 28c.

The output pulse of the rotary encoder 24 is applied to the pulse generation circuit 30, and the pulse width control signal is applied from the conversion circuit 28c of the control device 28. The pulse generation circuit 30 includes a rotary encoder 24.
And a pulse signal having a pulse width corresponding to the pulse width control signal from the conversion circuit 28c of the control device 28 is generated. The pulse signal generated by the pulse generation circuit 30 is passed through the gate circuit 32 and the laser oscillator 34
Is applied to The laser oscillator 34 includes a gate circuit 32.
A pulse is generated in accordance with the pulse signal from the laser beam to irradiate the continuous paper 10 with a laser pulse.

A so-called carbon dioxide gas laser is suitable for the laser oscillator 34. Its output beam is directly
Alternatively, the continuous paper 10 is irradiated with light through a predetermined guide optical system. It is clear that the installation location of the laser oscillator 34 can be made free to some extent by providing the guide optical system.

The main control circuit 28d of the controller 28 controls the opening / closing of the gate circuit 32 according to the set paper processing information and the count value of the counter 28a. For example, FIG.
As shown by reference numeral 16, it is assumed that a vertical perforation is made in the length of B1 from the position of A1 from the edge of the sheet 10a. The vertical perforation 16 has, for example, a cut width of 2 mm and a tie width of 1
It is assumed to be mm. At this time, the main control circuit 28d of the control device 28 controls the opening / closing of the gate circuit 32 at the timing as shown in FIG. 3A shows the output of the paper edge detection device 26, FIG. 3B shows the output of the rotary encoder 24, FIG. 3C shows the output of the pulse generation circuit 30, and FIG. 3D shows the opening / closing control for the gate circuit 32. The signal (e) is an optical pulse output from the laser oscillator 34. Actually, the gate circuit 32 applied 19 pulses to the laser oscillator 34 for the cut portion and shielded 9 pulses for the tie portion.

In this embodiment, the pulse generating circuit 30 generates a pulse synchronized with the output pulse of the rotary encoder 24. Therefore, the frequency f (= 1 / T) of the output pulse of the pulse generation circuit 30, that is, the frequency of the laser output of the laser oscillator 34 is proportional to the paper feed speed v of the continuous paper 10. In the laser oscillator 34 used, when the drive pulse frequency is increased, the average laser output increases almost in proportion to it. In general, it is necessary to increase the laser energy to be applied to the paper 10 in order to obtain the same paper processing ability when the feeding speed v of the continuous paper 10 is increased. In the present embodiment, this is realized by changing the pulse oscillation frequency of the laser oscillation device 34 according to the paper feed speed v of the continuous paper 10, and is appropriate even when the continuous paper 10 is accelerated or decelerated. It is possible to apply various laser powers to the paper 10, and it is possible to prevent the paper 10 from being scorched and being unable to penetrate a portion which should be penetrated.

However, in the present embodiment, the control device 28 further controls the pulse generation circuit 3 according to the paper feed speed v of the paper 10.
It controls the pulse width generated by 0 and thus the duration t of the laser beam output by the laser oscillator 34. Specifically, the slower the feeding speed v of the paper 10, the longer the duration t of the laser beam is in inverse proportion to the feeding speed v. The reason is as follows.

That is, since the laser oscillating device 34 is basically driven by a pulse, spot-shaped holes are formed in the paper 10. The continuous spots realize a desired length of cut. The paper feeding speed is v, the duration of the output laser beam of the laser oscillator 34 is t,
The period is T, and the width of the output laser beam of the laser oscillator 34 (that is, the beam diameter in the feeding direction of the paper 10) is W. In order for the spots by the individual laser pulses to overlap with the adjacent spots as shown in FIG. 4, the overlap rate α given by the following equation must be larger than 0.

Α = (W + vt−vT) / (W + vt) (1) Half of the laser beams, that is, W / 2 or more, is preferably overlapped. To satisfy this, W + vt−vT ≧ W / 2 ( 2) Therefore, T, t may be adjusted with respect to v so that W / 2 ≧ v (T−t) (3).

When the equation (1) is modified, v (1- (1-α) t / T) = (1-α) W / T (4), and the feeding speed v of the sheet 10 and the duty ratio (t /
The relationship with T) is as shown in FIG. 5, and (t / T) must be increased as the feeding speed v of the sheet 10 is increased. That is, as the feeding speed v of the sheet 10 is increased,
Either increase the duration t of the laser pulse, decrease the period T of the laser pulse, or decrease T while increasing t.

When the equation (4) is modified, t = T / (1-α) -W / v (5)

In the present embodiment, the cycle T of the laser pulse is inversely proportional to the feed speed v of the paper 10 so that the average laser output is almost constant regardless of the paper feed speed v. Therefore, it can be expressed as T = K / v (6). K is a constant. Substituting equation (6) into equation (5) yields vt = K / (1-α) -W (7).

Therefore, the period T of the laser pulse is set to the paper 1
In the case where the laser beam spots are overlapped in the case of being inversely proportional to the feeding speed v of 0, t may be inversely proportional to v. As the paper feeding speed v of the paper 10 is increased, the laser pulse The duration t may be small. In other words,
From the stopped state until the target speed is reached, or
When the feeding speed v of the paper 10 is slower than the target speed, such as when the paper 10 cannot be conveyed at the target speed for some reason, the drive pulse width for the laser oscillator 34, that is, the pulse generation circuit 30 is generated accordingly. It is necessary to widen the pulse width. As a result, it is possible to cleanly process (cut here) without making the target length uneven.

Although theoretically as described above, in general,
The pulse width of the drive pulse (pulse generated by the pulse generation circuit 30) applied to the laser oscillator 34 and the duration t of the laser pulse generated by the laser oscillator 34 by this drive pulse do not necessarily match. Therefore, it is necessary to measure the correspondence between the pulse width of the drive pulse and the duration t of the laser pulse generated by the laser oscillator 34 in advance, depending on the laser oscillator 34 used. In consideration of the above, the correspondence between the feed speed v of the sheet 10 and the width of the drive pulse generated by the pulse generation circuit 30 is programmed in the conversion circuit 28c of the control device 28.

The average output also changes according to the change in t, but for continuous processing (cutting in this case), the power applied at the overlapping portion of the continuous spots by the laser beam becomes a problem, and the cutting In this case, the change in power is almost negligible. In the case of half-cut, it is of course necessary to keep the laser power applied to each processing target part within a certain range more strictly than in the case of cut, and for that purpose, for example, α is possible. Make it small within a certain range.

The laser average output with respect to the paper feed speed v can be adjusted by the drive pulse width, but it is easier by the pulse period T and can be finely adjusted. In the case of a cut, the overlap of spots on the paper 10 by the laser beam can be quite rough. Therefore, the configuration in which the average laser power is adjusted by the period T and the spot overlap is adjusted by the duration t of the laser beam as in this embodiment has an advantage that desired performance can be easily realized.

Further, for example, when the laser average output with respect to the paper feed speed v is adjusted by the drive pulse width and the period T is kept constant, as can be seen from the equation (3), the laser spots overlap. , V the smaller the duration t of the laser pulse needs to be.

Although the example of forming the vertical perforation has been described, it is obvious that the vertical slit can be formed by this embodiment.

The usage and operation of this embodiment will be briefly described. For example, it is assumed that the regions A1 and A2 in FIG. 2 are not processed, and that the vertical perforation of the cut portion 2 mm and the tie portion 1 mm is formed in the region B1. First, the output power (for example, 50 W to 150 W) of the laser oscillator 34 at the target speed of the continuous paper 10, for example, 300 feet / minute is set, and the output pulse width of the pulse generation circuit 30 is set in accordance with the thickness of the continuous paper 10. (For example, 10 μs to 25 μs) is controlled by the controller 2
Set to 8. Further, the main control circuit 28 of the controller 28
In d, a paper processing condition for forming a vertical perforation having a cut portion of 2 mm and a tie portion of 1 mm in the area B1 is input.

The continuous paper 10 is guided by the guide rollers 20, 20.
In the meantime, the tractor pin of the tractor device 22 is engaged with the feed hole 12 and the tractor device 22 is driven to start the feeding of the continuous paper 10, and the continuous speed is accelerated to the target speed. In this embodiment, paper processing can be started even during acceleration.

When the feeding of the continuous paper 10 is started, the rotary encoder 24 is set to 1 by the feed amount of the continuous paper 10.
240 pulses per inch are supplied to controller 28 and pulse generation circuit 30. The paper edge detection device 26 detects the front edge of the paper 10a that is the processing unit of the continuous paper 10,
The front end detection pulse is supplied to the controller 28. As described above, the counter 28a of the control device 28 starts counting output pulses of the rotary encoder 24 by the paper edge detection pulse of the paper edge detection device 26, and clears for each page size input in advance. To be done. Counter 28
The count value of a indicates the current position on the sheet 10a in the page size input in advance.

The cycle measuring circuit 28b of the controller 28 measures the cycle of the output pulse of the rotary encoder 24. The reciprocal of the measured cycle is the paper feed speed v of the paper 10.
It is clear that Conversion circuit 2 of control device 28
Reference numeral 8c is a pulse that converts the output of the cycle measuring circuit 28b into a pulse width control signal indicating the pulse width at the current paper feed speed v based on the pulse width at the reference speed instructed by the main control circuit 28d. It is applied to the generation circuit 30. The main control circuit 28d keeps the gate circuit 32 closed until the processing start point, that is, the area B1 is reached.

The pulse generation circuit 30 generates a drive pulse having a pulse width which is synchronized with the pulse from the rotary encoder 24 and which is defined by the pulse width control signal from the conversion circuit 28c of the control device 28, and the gate circuit. 32.

The main control circuit 28d of the control device 28 controls the opening / closing of the gate circuit 32 in synchronization with the output pulse of the rotary encoder 24 so that a repetitive pattern of the cut portion 2 mm and the tie portion 1 mm is formed in the processing target area B1. To do. That is, the main control circuit 28d supplies the 19 output pulses of the pulse generation circuit 30 to the laser oscillation device 34 with respect to the cut portion and allows the gate circuit 32 to pass, and closes the gate circuit 32 with respect to the tie portion. Thus, the nine output pulses of the pulse generation circuit 30 are shielded.

The laser oscillator 34 oscillates a laser pulse in response to the pulse from the gate circuit 32, and irradiates the continuous paper 10 with the laser pulse. As a result, a small spot-shaped hole corresponding to the size of the laser beam is opened at the irradiation position of the continuous paper 10. By overlapping the spot-like holes, a cut portion having a desired length is formed.

When the area A2 is reached, the main control circuit 28 of the controller 28 closes the gate circuit 32 so that the laser oscillator 34 does not output the laser until the next sheet 10a.

In this way, the paper 10a is repeated as a unit on the continuous paper 10 and the same range B of the paper 10a is repeated.
A vertical perforation is formed at 1.

Although the embodiment in which the laser beam cannot be scanned in the lateral direction of the continuous paper 10 has been described, an optical system for continuously scanning the laser beam in the lateral direction of the continuous paper 10, for example, a polygon mirror is used, By applying the equation (1) to the composite velocity vector of the beam lateral scanning velocity and the paper feed velocity v, the paper processing along the direction inclined from the paper feed direction can be similarly realized. If the scanning direction of the laser beam is tilted from the direction orthogonal to the paper feeding direction, paper processing in the direction orthogonal to the paper feeding direction can be similarly realized.

In the above embodiment, the rotary encoder 24 in which the signal indicating the sheet feed amount is connected to the tractor device 22.
However, the signal indicating the sheet feeding may be obtained from the roll conveying device. That is, for example, when the above laser processing device is incorporated in a printing machine, a signal indicating the sheet feed amount can be obtained from a rotary encoder connected to the roll transport device of the printing machine.

[0048]

As can be easily understood from the above description, according to the present invention, a desired length can be cleanly processed regardless of the paper feed speed even when the paper to be processed is continuously fed. . That is, the spots of the laser beams can be neatly overlapped, and a smooth processed end face having a desired length can be obtained. Since laser processing is used, no paper dust is generated and no burr is generated on the processed end surface.

Further, since the irradiation lens corresponding to the processing size is not required and the processing pattern can be set by the paper processing information, it is possible to flexibly deal with various processing patterns. That is, it is possible to form a sewing machine, a skip sewing machine, and a slit having an arbitrary size and an arbitrary size.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an embodiment of the present invention.

FIG. 2 is a plan view of a continuous sheet to be processed.

FIG. 3 is a timing chart of the present embodiment.

FIG. 4 is an explanatory diagram of overlapping of laser beam spots.

FIG. 5 is a diagram showing a relationship between a feeding speed v of the sheet 10 and a duty ratio (t / T) in Expression (4).

[Explanation of symbols]

10: Continuous paper 10a: Paper that serves as a basic unit for vertical perforation processing and printing 12: Feed hole 14: Horizontal perforation for folding and cutting 16: Vertical perforation 20: Guide roller 22: Tractor device 24: Rotary Encoder 26: Paper edge detection device 28: Control device 28a: Counter 28b: Period measurement circuit 28c: Conversion circuit 28d: Main control circuit 30: Pulse generation circuit 32: Gate circuit 34: Laser oscillation device

Claims (11)

[Claims] 1. A laser beam is applied to a moving sheet in the length direction thereof.
A laser processing apparatus for processing with a beam, a movement amount detecting means for detecting a movement amount of the sheet, a cycle according to a predetermined movement amount of the sheet according to an output of the movement amount detecting means, and By pulse generation means for generating a pulse having a pulse width that changes according to the feed speed of the paper, gate means for passing or blocking the output pulse of the pulse generation means according to the processing pattern, and output of the gate means A laser processing apparatus comprising: a laser oscillating unit that is pulse-driven and that generates a laser beam to be irradiated onto a processed portion of the sheet. 2. The laser processing apparatus according to claim 1, wherein the pulse width generated by the pulse generating means becomes wider as the sheet feeding speed becomes slower. 3. Laser oscillating means capable of changing at least one of duration and period of a laser beam pulse,
Driving means for generating a pulse for driving the laser oscillating means, speed detecting means for detecting a relative feed speed of a processing target with respect to a laser beam generated by the laser oscillating means, and a detection result of the speed detecting means And a control means for adjusting at least one of the width and the cycle of the pulse to be output from the driving means, and controlling the presence or absence of the pulse output of the driving means according to the set processing information. . 4. The pulse generating means, wherein the driving means generates a pulse signal having a pulse width and a cycle defined by the output of the speed detecting means and the control signal of the control means,
4. A gate means for blocking the output pulse of the pulse generation means under the control of the control means.
The laser processing apparatus described in. 5. The laser processing apparatus according to claim 4, wherein the pulse generating means generates a pulse signal having a pulse width defined by the control means at a cycle corresponding to the speed detected by the speed detecting means. . 6. The control means controls the pulse width generated by the pulse generating means in accordance with the feed speed of the processing target such that the slower the feed speed is, the wider the pulse width is. The laser processing apparatus described in. 7. The control means controls the drive means so that the period of the pulse output by the drive means is T, the duration of the laser pulse output by the laser oscillation means is t, and the laser beam When the width is W and the relative moving speed of the processing target is v, for continuous processing with a laser beam width W or more, t = T / (1-α) −W / v where 0 <α The laser processing apparatus according to claim 6, wherein at least one of t and T is adjusted so as to satisfy <1. 8. The laser processing according to claim 7, wherein the control means further adjusts at least one of T and t so that a relationship of W / 2 ≧ v (T−t) is satisfied with respect to v. apparatus. 9. The pulse generating means, wherein the driving means generates a pulse signal having a pulse width and a cycle defined by the output of the speed detecting means and the control signal of the control means.
9. The laser processing apparatus according to claim 7, further comprising gate means for passing and blocking an output pulse of the pulse generating means under the control of the control means. 10. A laser processing apparatus for processing a relatively moving sheet into a desired pattern by a laser pulse, wherein the period of the laser pulse is T, the duration of the laser pulse is t, and the laser pulse is When the beam width is W and the relative moving speed of the paper is v, the laser beam width W
For the above continuous machining, t = T / (1-α) −W / v, where any one of v, t and T is adjusted so as to satisfy 0 <α <1. Laser processing equipment. 11. The laser processing apparatus according to claim 10, wherein at least one of T and t is adjusted so that the following expression W / 2 ≧ v (T−t) is satisfied with respect to v.