JP3632249B2 - Laser processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing apparatus, and more specifically to a laser processing apparatus that processes a relatively moving sheet with a laser beam in the moving direction.
[0002]
[Prior art]
A conventional processing device that forms vertical perforations, vertical slits, half slits, etc. on continuous paper is driven by rotating a slit blade or vertical sewing blade suitable for the processing size in synchronization with the feed speed of the continuous paper. A vertical perforation or the like having a desired size is formed on the surface. To change the machining size, replace it with a slit blade or vertical sewing machine blade suitable for the new machining size. Moreover, when the cutting of the blade becomes worse, it is replaced with a new blade.
[0003]
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.
[0004]
On the other hand, a laser processing apparatus that performs non-contact processing using a laser beam has been proposed. For example, vertical perforations are described in the third column, right column, line 30 and subsequent lines of 1994 Patent Application Publication No. 65479. According to such laser processing, not only paper dust is not generated, but also the processed surface becomes smooth and burrs are eliminated. There is no need to replace the slit blade or the vertical sewing machine blade due to wear.
[0005]
[Problems to be solved by the invention]
However, in the configuration described in the above publication, since the size of the vertical perforation is defined by the irradiation lens 7, an irradiation lens 7 suitable for the new processing size must be installed every time the processing size is changed. Is troublesome. Depending on the optical performance of the irradiation lens 7, selectable processing sizes are limited. For example, it is impossible to form a long slit with the configuration described in the above publication.
[0006]
An object of this invention is to show the laser processing apparatus which can respond flexibly to the change of process size.
[0007]
Further, the paper feed speed is not always constant. For example, the speed is initially low, and the speed is gradually increased and stabilized at the initial target speed. Therefore, it is desired that not only the processing at the target speed but also the processing at a desired size can be performed at a speed lower than the target speed, and also during acceleration / deceleration.
[0008]
Accordingly, an object of the present invention is to provide a laser processing apparatus that can process a desired size even at different paper feed speeds.
[0009]
[Means for Solving the Problems]
A laser processing apparatus according to the present invention is a laser processing apparatus that processes a moving sheet with a laser beam in the length direction thereof, a movement amount detection unit that detects a movement amount of the sheet, and the movement amount detection unit. depending on the output, at a cycle corresponding to the amount of movement of the sheet, moreover, a pulse width that varies depending on the feeding speed of the paper, a pulse width feeding speed of the sheet is wider slower pulse Pulse generating means, a gate means for passing / blocking an output pulse of the pulse generating means according to the processing pattern, and a pulse drive by the output of the gate means to irradiate the processed portion of the paper characterized by comprising a laser oscillating means for generating a laser beam of constant peak power to.
[0010]
A laser processing apparatus according to the present invention generates a laser beam generating means for generating a laser beam having a constant peak power, the duration and period of which can be changed, and a pulse for driving the laser beam oscillating means. A driving means, a speed detecting means for detecting a relative feed speed of a processing object with respect to a laser beam generated by the laser oscillating means, and a pulse width to be output by the driving means in accordance with a detection result of the speed detecting means And control means for adjusting at least one of the cycles and controlling the presence or absence of pulse output of the driving means in accordance with the set machining information. The drive 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 detection means, and the pulse under the control of the control means. Gate means for passing through and blocking the output pulse of the generating means. The control means controls the pulse width generated by the pulse generating means in accordance with the feed speed of the processing target so that the pulse width becomes wider as the feed speed is slower.
[0011]
A laser processing apparatus according to the present invention is a laser processing apparatus that processes a relatively moving sheet into a desired pattern by a laser pulse, wherein the period of the laser pulse is T, and the duration of the laser pulse is t, where the width of the laser beam is W, and the relative moving speed of the paper is v, for continuous processing of the laser beam width W or more,
t = T / (1-α) −W / v
However, 0 <α <1
Any one of v, t, and T is adjusted to satisfy the above condition.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 shows a schematic block diagram of an embodiment of the present invention, and FIG. 2 shows a plan view of continuous paper to be processed. As shown in FIG. 2, the continuous paper 10 is provided with a large number of feed holes 12 at the left and right ends for feeding paper. Horizontal perforations 14 that are folded and cut at regular intervals in the longitudinal direction are formed by another processing apparatus. The sheet 10a cut by the folding / cutting horizontal perforation 14 becomes a basic unit for vertical perforation and printing.
[0014]
Referring to FIG. The continuous paper 10 is continuously conveyed leftward in FIG. 1 by the tractor device 22 while being guided by a pair of guide rollers 20 and 20. The tractor device 22 includes a tractor pin (not shown) that engages with the feed hole 12 of the continuous paper 10, and conveys the continuous paper 10 at a desired speed by rotating. A rotary encoder 24 is fixed to the rotating shaft of the tractor device 22. The rotary encoder 24 of the present embodiment generates 240 pulses for 1 inch feed of the continuous paper 10. Since the processing unit of the paper is usually 1/3 inch, 1/6 inch, 1/8 inch or 1/10 inch, the rotary encoder 24 generating 240 pulses per inch is used for such processing. It becomes easy to correspond to the unit.
[0015]
The paper edge detection device 26 detects the edge of the paper 10a that is the basis of the vertical perforation. For example, the paper edge detection device 26 may be 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.
[0016]
The output of the rotary encoder 24 and the output of the paper end detection device 26 are applied to the control device 28. The control device 28 comprises a so-called personal computer or its extension board, and paper processing information is set from a keyboard or other input device. The paper processing information includes a processing start position, a processing end position, and processing pattern information for the paper 10a. The processing pattern information is, for example, information on a basic periodic pattern of a cut length and a tie length, whereby an arbitrary vertical cut pattern can be set.
[0017]
Obviously, 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 clear that when the laser beam can be irradiated to different positions in the lateral direction of the continuous paper 10, lateral position information indicating at which position in the lateral direction of the continuous paper 10 laser processing is also necessary.
[0018]
The control device 28 includes a counter 28 a that counts the number of output pulses of the rotary encoder 24, and the counter 28 a is cleared by a paper end detection pulse of the paper end detection device 26. The paper edge detection pulse of the paper edge detection device 26 is time-adjusted by an amount corresponding to the distance difference between the installation position of the paper edge detection device 26 and the laser processing position. The count value of the counter 28a indicates the current position on the paper 10a serving as a processing unit.
[0019]
The control device 28 also includes a period measurement circuit 28 b that measures the period of the output pulse of the rotary encoder 24. Since the output of the rotary encoder 24 is 240 pulses per 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 period measurement circuit 28b. Although details will be described later, in this embodiment, the duration of the laser pulse is adjusted according to the paper feed speed v. 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 a pulse width obtained by correcting a reference pulse width at a reference paper feed speed based on the principle described below. Information on the reference pulse width (changed according to the paper thickness) at the reference paper feed speed is set in the conversion circuit 28c as necessary.
[0020]
The controller 28 further includes a main control circuit 28d that controls the application of laser pulses to the continuous paper 10 in accordance with the set paper processing conditions. The main control circuit 28d sets the reference pulse width at the reference paper feed speed set by the user in the conversion circuit 28c.
[0021]
The pulse generation circuit 30 is supplied with the output pulse of the rotary encoder 24 and the pulse width control signal from the conversion circuit 28 c of the control device 28. The pulse generation circuit 30 generates a pulse signal having a pulse width synchronized with the output pulse of the rotary encoder 24 and corresponding to the pulse width control signal from the conversion circuit 28 c of the control device 28. The pulse signal generated by the pulse generation circuit 30 is applied to the laser oscillation device 34 via the gate circuit 32. The laser oscillation device 34 oscillates in accordance with the pulse signal from the gate circuit 32 and irradiates the continuous paper 10 with the laser pulse.
[0022]
As the laser oscillation device 34, a so-called carbon dioxide laser is suitable. The output beam is irradiated onto the continuous paper 10 directly or via a predetermined guide optical system. It is obvious that the installation location of the laser oscillation device 34 is somewhat freed by providing the guide optical system.
[0023]
The main control circuit 28d of the control device 28 controls the opening and closing of the gate circuit 32 according to the set paper processing information and the count value of the counter 28a. For example, as indicated by reference numeral 16 in FIG. 2, it is assumed that a vertical perforation is made in the length B1 from the position A1 from the end of the paper 10a. For example, the vertical perforations 16 have a cut width of 2 mm and a tie width of 1 mm. At this time, the main control circuit 28d of the control device 28 controls the opening and closing of the gate circuit 32 at the timing 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 oscillation device 34 with respect to the cut portion, and shielded 9 pulses with respect to the tie portion.
[0024]
In this embodiment, the pulse generation circuit 30 generates a pulse synchronized with the output pulse of the rotary encoder 24. Accordingly, 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 oscillation device 34 is proportional to the paper feed speed v of the continuous paper 10. In the used laser oscillation device 34, when the drive pulse frequency is increased, the average laser output increases in proportion to the drive pulse frequency. Generally, in order to obtain the same paper processing capability when the feed speed v of the continuous paper 10 is increased, it is necessary to increase the laser energy to be applied to the paper 10. In the present embodiment, this is realized by changing the pulse oscillation frequency of the laser oscillation device 34 in accordance with the paper feed speed v of the continuous paper 10, and is appropriate even when the continuous paper 10 is accelerated or decelerated. Therefore, it is possible to prevent the paper 10 from being burnt or being able to penetrate the portion to be penetrated.
[0025]
However, in the present embodiment, the control device 28 further determines the pulse width generated by the pulse generation circuit 30 and thus the duration t of the laser beam output from the laser oscillation device 34 in accordance with the paper feed speed v of the paper 10. Control. Specifically, the lower the feed speed v of the paper 10, the longer the laser beam duration t is in inverse proportion to the feed speed v. The reason for this is as follows.
[0026]
That is, since the laser oscillation device 34 is basically pulse-driven, spot-like holes are made in the paper 10. A cut having a desired length is realized by the continuous spots. The feed speed of the paper is v, the duration of the output laser beam of the laser oscillator 34 is t, the period is T, the width of the output laser beam of the laser oscillator 34 (that is, the beam diameter in the feed direction of the paper 10). Is W. In order for spots due to individual laser pulses to overlap with adjacent spots as shown in FIG. 4, the overlap rate α given by the following equation must be greater than zero.
[0027]
α = (W + vt−vT) / (W + vt) (1)
To satisfy this, it is preferable to overlap half of the laser beam, ie, W / 2 or more.
W + vt−vT ≧ W / 2 (2)
Therefore,
W / 2 ≧ v (T−t) (3)
It is sufficient to adjust T and t with respect to v so that
[0028]
When formula (1) is transformed,
v (1- (1-α) t / T) = (1-α) W / T (4)
Thus, the feeding speed v of the paper 10 and the duty ratio (t / T) have a relationship as shown in FIG. 5, and the higher the feeding speed v of the paper 10, the larger (t / T) must be made. Don't be. That is, as the feed speed v of the paper 10 is increased, the duration t of the laser pulse is increased, the period T of the laser pulse is decreased, or T is decreased while increasing t. .
[0029]
When equation (4) is transformed,
t = T / (1-α) −W / v (5)
It becomes.
[0030]
In this embodiment, the period T of the laser pulse is made inversely proportional to the feed speed v of the paper 10 so that the laser average output becomes substantially constant regardless of the paper feed speed v. Therefore,
T = K / v (6)
Can be written. K is a constant. Substituting equation (6) into equation (5),
vt = K / (1-α) −W (7)
It becomes.
[0031]
Therefore, in the case where the laser pulse period T is inversely proportional to the feed speed v of the paper 10, in order for the laser beam spots to overlap, t may be inversely proportional to v. The faster v is, the smaller the laser pulse duration t may be. In other words, when the feed speed v of the paper 10 is slower than the target speed, such as when the paper 10 is not transported at the target speed from a stopped state until the target speed is reached, or for whatever reason, Accordingly, the drive pulse width for the laser oscillation device 34, that is, the pulse width generated by the pulse generation circuit 30 must be increased. Thereby, it can process neatly (cut here), without making the target length uneven.
[0032]
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 oscillation device 34 and the laser generated by the laser oscillation device 34 by this drive pulse. -The pulse duration t does not necessarily match. Therefore, it is necessary to measure in advance 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 accordance with the laser oscillator 34 to be used. In consideration of the above, the correspondence between the feed speed v of the paper 10 and the width of the drive pulse generated by the pulse generation circuit 30 is programmed in the conversion circuit 28 c of the control device 28.
[0033]
The average output also changes with the change of t, but for continuous machining (here, cutting), the power applied at the overlapping portion of the continuous spots by the laser beam becomes a problem. The change in power is almost negligible. In the case of half-cutting, it is of course necessary to keep the laser power applied to each part to be processed within a certain range more strictly than in the case of cutting. For this purpose, for example, α is possible. Make it smaller within a certain range.
[0034]
Although the laser average output with respect to the paper feed speed v can be adjusted by the drive pulse width, it is easier and finely adjusted by the pulse period T. In the case of a cut, the overlap of spots on the paper 10 by the laser beam can be quite rough. Therefore, as in this embodiment, the configuration in which the laser average output is adjusted by the period T and the spot overlap is adjusted by the laser beam duration t has an advantage that desired performance can be easily realized.
[0035]
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 constant, for the overlap of laser spots, as can be seen from Equation (3), v is The smaller the value, the smaller the laser pulse duration t.
[0036]
Although an example in which the vertical perforation is formed has been described, it is obvious that a vertical slit can also be formed according to this embodiment.
[0037]
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 a vertical perforation having a cut portion of 2 mm and a tie portion of 1 mm is formed in the region B1. First, the output power (for example, 50 W to 150 W) of the laser oscillation device 34 at a 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 corresponding to the thickness of the continuous paper 10. (For example, 10 μs to 25 μs) is set in the control device 28. Further, paper processing conditions for forming a vertical perforation having a cut portion of 2 mm and a tie portion of 1 mm in the region B1 are input to the main control circuit 28d of the control device 28.
[0038]
The continuous paper 10 is passed between the guide rollers 20, 20, the tractor pin of the tractor device 22 is engaged with the feed hole 12, the tractor device 22 is driven to start feeding the continuous paper 10, and the target speed Will gradually accelerate. In this embodiment, paper processing can be started even during acceleration.
[0039]
When the continuous paper 10 starts to be fed, the rotary encoder 24 supplies 240 pulses per inch to the control device 28 and the pulse generation circuit 30 according to the feed amount of the continuous paper 10. The paper edge detection device 26 detects the front edge of the paper 10 a that is a processing unit of the continuous paper 10 and supplies a front edge detection pulse to the control device 28. As described above, the counter 28a of the control device 28 starts counting the output pulses of the rotary encoder 24 by the paper end detection pulse of the paper end detection device 26 and clears it for each page size inputted in advance. Is done. The count value of the counter 28a indicates the current position on the paper 10a at the page size input in advance.
[0040]
The period measuring circuit 28 b of the control device 28 measures the period of the output pulse of the rotary encoder 24. It is clear that the reciprocal of the measured period indicates the paper feed speed v of the paper 10. The conversion circuit 28c of the control device 28 outputs 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, which is instructed from the main control circuit 28d. And applied to the pulse generation circuit 30. The main control circuit 28d keeps the gate circuit 32 closed until reaching the processing start point, that is, the region B1.
[0041]
The pulse generation circuit 30 generates a drive pulse having a pulse width that is synchronized with the pulse from the rotary encoder 24 and defined by the pulse width control signal from the conversion circuit 28 c of the control device 28, and applies it to the gate circuit 32. To do.
[0042]
The main control circuit 28d of the control device 28 controls the gate circuit 32 to open and close in synchronization with the output pulse of the rotary encoder 24 so that the processing target region B1 has a repeated pattern of a cut portion of 2 mm and a tie portion of 1 mm. That is, the main control circuit 28d passes the gate circuit 32 through the cut portion and supplies the 19 output pulses of the pulse generation circuit 30 to the laser oscillation device 34, and closes the gate circuit 32 at the tie portion. Thus, the nine output pulses of the pulse generation circuit 30 are shielded.
[0043]
The laser oscillation device 34 oscillates a laser pulse in accordance with the pulse from the gate circuit 32 and irradiates the continuous paper 10 with the laser pulse. As a result, a small spot-like hole corresponding to the size of the laser beam is opened at the irradiation position of the continuous paper 10. A spot-shaped hole overlaps to form a cut portion having a desired length.
[0044]
When the area A2 is reached, the main control circuit 28 of the control device 28 closes the gate circuit 32 so that the laser oscillation device 34 does not output laser until the next sheet 10a.
[0045]
In this way, on the continuous paper 10, the paper 10a is repeated as a unit, and vertical perforations are formed in the same range B1 of the paper 10a.
[0046]
The embodiment in which the laser beam cannot be scanned in the lateral direction of the continuous paper 10 has been described. However, in the case where an optical system that continuously scans the laser beam in the lateral direction of the continuous paper 10, for example, a polygon mirror, is provided, By applying Equation (1) to the combined speed vector of the horizontal scanning speed and the paper feed speed v, 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 perpendicular to the paper feed direction, paper processing in the direction perpendicular to the paper feed direction can be similarly realized.
[0047]
In the above embodiment, the signal indicating the sheet feeding amount is obtained from the rotary encoder 24 connected to the tractor device 22, but a signal indicating the sheet feeding may be obtained from the roll conveying device. That is, for example, when the laser processing apparatus is incorporated in a printing press, a signal indicating the paper feed amount can be obtained from a rotary encoder connected to the roll conveying device of the printing press.
[0048]
【The invention's effect】
As can be easily understood from the above description, according to the present invention, it is possible to cleanly process a desired length regardless of the paper feed speed even in a state where the paper to be processed is continuously fed. That is, the laser beam spots can be neatly overlapped to obtain a smooth processed end face with a desired length. Because of laser processing, no paper dust is generated and no burrs are formed on the processed end face.
[0049]
In addition, an irradiation lens corresponding to the processing size is not required, and the processing pattern can be set based on the paper processing information, so that various processing patterns can be flexibly handled. That is, it is possible to form an arbitrary size sewing machine, a skip sewing machine, and a slit having an arbitrary tie cut.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of an embodiment of the present invention.
FIG. 2 is a plan view of continuous paper to be processed.
FIG. 3 is a timing chart of the present embodiment.
FIG. 4 is an explanatory diagram of overlapping laser beam spots.
FIG. 5 is a diagram illustrating a relationship between a feeding speed v of a sheet 10 and a duty ratio (t / T) by Expression (4).
[Explanation of symbols]
10: continuous paper 10a: paper which becomes a basic unit for vertical perforation processing and printing, etc. 12: feed hole 14: transverse perforation 16 for folding and cutting 16: vertical perforation 20: guide roller 22: tractor device 24: rotary Encoder 26: Paper end 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 (7)

A laser processing apparatus for processing a moving sheet with a laser beam in its length direction,
A movement amount detecting means for detecting a movement amount of the paper;
Depending on the output of the displacement detection means, at a cycle corresponding to the amount of movement of the sheet, moreover, a pulse width that varies depending on the feeding speed of the sheet, as the feeding speed of the sheet is slow wide Pulse generating means for generating a pulse having a pulse width of
Gate means for passing and blocking the output pulse of the pulse generating means according to the machining pattern;
A laser processing apparatus comprising: laser oscillation means that generates a laser beam having a constant peak power that is pulse-driven by the output of the gate means and is to be irradiated to a processing portion of the paper. Laser oscillation means for generating a laser beam having a constant peak power, the duration and period of the laser beam pulse being freely changeable , and
Driving means for generating a pulse for driving the laser oscillation means;
Speed detecting means for detecting a relative feed speed of a processing object with respect to a laser beam generated by the laser oscillating means;
Control means for adjusting at least one of a width and a period of a pulse to be output from the driving means according to the detection result of the speed detecting means, and controlling the presence or absence of the pulse output of the driving means according to set processing information. ,
The drive 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 detection means, and the pulse under the control of the control means. Gate means for blocking the output pulse of the generating means,
The control means controls the pulse width generated by the pulse generating means according to the feed speed of the machining target so that the pulse width becomes wider as the feed speed is slower. Laser processing equipment. The control means controls the driving means, the period of the pulse output from the driving means is T, the duration of the laser pulse output from the laser oscillating means is t, the width of the laser beam is W, processing When the relative movement speed of the object is v, for continuous processing of the laser beam width W or more,
t = T / (1-α) −W / v
However, 0 <α <1
The laser processing apparatus according to claim 2 , wherein at least one of t and T is adjusted so as to satisfy the above. The control means further provides for v
W / 2 ≧ v (T−t)
The laser processing apparatus according to claim 3 , wherein at least one of T and t is adjusted so as to satisfy the relationship. The driving means generates a pulse signal having a pulse width and a period defined by the output of the speed detecting means and the control signal of the control means, and under the control of the control means, the pulse generating means the laser processing apparatus according to claim 3 or 4 comprising a gate means for passing and blocking the output pulse. A laser processing apparatus for processing a relatively moving paper into a desired pattern by a laser pulse,
Continuous machining with a laser beam width of W or more, where T is the period of the laser pulse, t is the duration of the laser pulse, W is the width of the laser beam, and v is the relative moving speed of the paper. Against
t = T / (1-α) −W / v
However, 0 <α <1
Any of v, t, and T is adjusted so that it may satisfy | fill, The laser processing apparatus characterized by the above-mentioned. With respect to v, the following formula W / 2 ≧ v (T−t)
The laser processing apparatus according to claim 7 , wherein at least one of T and t is adjusted so as to satisfy

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