JP4619865B2 - Sheet length measuring device, sheet sorting line, sheet cutting line, and sheet length measuring method - Google Patents

Description

  The present invention relates to a sheet length measuring device, a sheet sorting line, a sheet cutting line, and a sheet length measuring method, and in particular, a sheet length measuring device and sheet length measuring capable of accurately measuring the length of a sheet conveyed at high speed. The present invention relates to a method, and a sheet distribution line and a sheet cutting line having the sheet length measuring device.

  The lithographic printing plate is slit, cut and processed in a processing line, and then collected, packaged and shipped.

  One item in the shipping standard is the accuracy of the cut length, but there is a problem that the cut length varies depending on the performance of the cutter, so online inspection is performed to ensure that the cut length is at the specified accuracy. .

Conventionally, as a sheet length measuring device used for on-line inspection of cut length, a device using a CCD camera as a light receiving means has been generally used (Patent Documents 1 to 4, Non-Patent Document 1).
JP 2001-350222 A JP 2003-246499 A Japanese Patent Laid-Open No. 6-147836 JP-A-8-122204 Kawasaki Steel Technical Report “Online Dimension / Shape Measurement Technology That Can Be Used for Hot Rolling”

  However, in recent years, the line speed of a lithographic printing plate production line has increased, so in an automatic sheet length measuring apparatus using a CCD camera as a light receiving means, it is difficult to synchronize the camera to meet the required accuracy, and it is several tens of μm. It was difficult to measure the sheet length with accuracy.

  The present invention has been made to solve the above problems, and a sheet length measuring device and a sheet distribution line capable of measuring a sheet length with high accuracy even when a sheet such as a lithographic printing plate is conveyed at high speed. An object of the present invention is to provide a sheet cutting line and a sheet length measuring method.

The invention according to claim 1 is a sheet length measuring device that measures a sheet length that is a length from a front edge to a rear edge of the sheet conveyed along a predetermined conveyance path, A light projecting portion for irradiating a surface of the sheet with pulsed light having a predetermined spread angle and a predetermined pulse period; and disposed on the opposite side of the light projecting unit across the sheet conveyance path. A light receiving unit that receives inspection light from the light unit; and a proximity sensor adjacent to the upstream side of the light projecting unit and the light receiving unit along a conveyance direction of the sheet, and the pulse light that is shielded by the sheet It determined the sheet and a number of pulses and the pulse interval of the pulse light a light-shielding time shielded inspection light, and a sheet length calculation means for obtaining the sheet length based on the transport speed of the said light-blocking time sheet Ete made it a sheet length measuring apparatus according to claim.

  In the sheet length measuring apparatus, components used in an optical communication system and an encoder can be used as components such as a light projecting unit, a light receiving unit, and a sheet length calculating unit. Since these parts have high performance and are relatively inexpensive, the sheet length measuring device can measure the sheet length online with high accuracy and can be configured at low cost.

Pulse invention according to claim 2, in the sheet length measuring apparatus according to claim 1, an optical fiber for guiding the light pulse from the light source, provided on the optical axis of the optical fiber, which is irradiated from the fiber A collimator unit that sets a light spread angle to a predetermined angle, and the light receiving unit receives a collimator unit disposed on an optical axis of the light projecting unit and inspection light converged by the collimator unit. And an optical fiber leading to the above.

  In the sheet length measuring device, the light projecting diameter of the inspection light in the light projecting portion and the light receiving diameter in the light receiving portion can be made smaller than the conventional example by about 5 to 50 μm. Here, since the sheet length can be measured with higher accuracy as the light projecting diameter and the light receiving diameter are smaller, the sheet length measuring device can measure the sheet length with much higher accuracy than the conventional one.

  In the sheet length measuring device, the light projecting unit generates high-frequency pulse light, which is received by the light receiving unit, converted into an electrical signal, amplified as necessary, and then the number of received light pulses is counted. The sheet length is measured by this method.

  Therefore, the sheet length can be measured with high accuracy on the order of several tens of μm by setting the light receiving diameter of the received light in the light receiving unit to be small and setting the frequency of the pulsed light in the light projecting unit to be large. As the light projecting unit, a light emitting element such as a semiconductor laser element that generates high-frequency pulsed light can be used. Such a light emitting element can be obtained at low cost.

The invention according to claim 3, in the sheet length measuring apparatus according to claim 1, wherein the light projecting unit and the composed of the light receiving portion emitting and receiving portion 1 Kumisonae, the sheet length calculation means, predetermined measurement The number of pulses P1 generated by the light projecting unit during time, the number P2 of pulses actually received by the light receiving unit, the conveying speed V (m / s) of the pulse sheet, and the pulse cycle T _PG (s) From the following formula:

To obtain the sheet length L.

  In the sheet length measuring device, since the sheet length is obtained based on the number of pulses (P1-P2) shielded by the sheet using one set of light projecting and receiving units, not only the configuration can be simplified but also the sheet length calculation The calculation procedure in the means can also be simplified.

Invention according to claim 4, in the sheet length measuring apparatus according to claim 1, wherein the light emitting and receiving parts may be two arranged along the conveying direction of the sheet, a pulse in synchronization in the light projecting portion The sheet length calculating means generates a distance D between the two light projecting / receiving units, a pulse number P1 generated in the light projecting unit in the light projecting / receiving unit during a predetermined measurement time, and a sheet conveying direction. And the number of pulses P2 detected in the light receiving unit disposed on the downstream side, the number of pulses P3 detected in the light receiving unit disposed on the upstream side with respect to the sheet conveyance direction, and the light projecting and receiving thereof. Based on the pulse period _TPG in the section and the sheet conveyance speed V, the following formula:

It is related with what calculates | requires sheet length L using.

  In the sheet length measuring device, it is not necessary to irradiate and detect pulsed light over the entire length of the sheet, so that the measurement time can be saved as compared with the sheet length measuring device according to claim 4. Therefore, it is particularly suitable for measuring a sheet having a long sheet length.

A fifth aspect of the present invention relates to the sheet length measuring apparatus according to the fourth aspect , wherein the distance D between the two light projecting / receiving portions can be changed according to the sheet length L.

According to a sixth aspect of the present invention, in the sheet length measuring device according to the fourth aspect of the present invention, three or more of the light projecting / receiving portions are disposed along the sheet conveying direction, and the sheet length calculating means is provided. Relates to a unit that performs sheet length measurement by selecting two of the light projecting and receiving units according to the sheet length L.

  In these sheet length measuring devices, since the distance D of the light projecting / receiving unit can be set according to the sheet length of the sheet to be measured, in the sheet length calculating means, the size of the distance D of the light projecting / receiving unit and the sheet length L is large or small. There is no need to use different calculation formulas depending on the relationship, and the logic for obtaining the sheet length can be simplified.

The invention according to claim 7 is the sheet length measuring device according to any one of claims 1 to 6 , further comprising a conveying speed measuring unit that measures a conveying speed of the sheet, and the sheet length calculating unit includes: Further, the present invention relates to an apparatus for obtaining a sheet length based on the number of pulses received by a light projecting / receiving unit or a light shielding time and the conveyance speed measured by the conveyance speed measuring means.

  The sheet whose sheet length is measured by the sheet length measuring apparatus of the present invention is not always conveyed at a constant speed.

  However, in the sheet length measuring device, the actual conveying speed of the sheet is measured by the conveying speed measuring unit, and the sheet length calculating unit corrects the calculation result of the sheet length using the conveying speed. Even in the above case, the sheet length can be measured with high accuracy.

According to an eighth aspect of the present invention, in the sheet length measuring device according to the seventh aspect , the light projecting / receiving unit is arranged in one or more sets along the sheet conveyance direction, and the sheet length calculation is performed. The means sets the conveyance speed measured by the conveyance speed measurement means to V (t), the sheet length measurement start time as t = 0, the sheet length measurement end time as t = Δt, and the average value of the conveyance speed V (t). When the average transport speed V _ave is set, the following formula:

The average conveyance speed V _ave is obtained based on the above, and the sheet length is obtained based on the obtained average conveyance speed V _ave .

  In the sheet length measuring device, the sheet speed is obtained by averaging the conveying speed V (t) measured by the conveying speed measuring means, so that when the variation in the conveying speed V (t) is small, the sheet length It is suitable when is short.

Invention according to claim 9, in the sheet length measuring apparatus according to claim 4, in each generation of the k-th pulse at the light projecting unit, the conveying speed measuring means conveying speed V of the sheet [( k / P1) · Δt] is measured and input to the sheet length calculating means, which calculates the following formula:

The sheet length L is obtained based on the above.

Each time the sheet length measuring device generates a pulse in the light projecting unit in the sheet length measuring device according to claim 5, the conveying speed measuring unit measures the conveying speed of the sheet, and the measured conveying speed and the pulse cycle T _PG The sheet length is obtained based on the sum of the products. Therefore, even when the sheet conveyance speed varies greatly during the sheet length measurement, the sheet length can be measured with high accuracy by shortening the pulse period _TPG .

A tenth aspect of the present invention is the sheet length measuring device according to any one of the first to ninth aspects, wherein a plurality of the light projecting / receiving units are provided along a direction orthogonal to the sheet conveying direction. The sheet length calculation means relates to a means for correcting the sheet length by obtaining an inclination θ with respect to the sheet conveyance direction based on a difference in light shielding timing in these light projecting and receiving portions.

  In the sheet length measuring device, the sheet length can be accurately measured even when the sheet is conveyed while being inclined with respect to the conveying direction.

The invention according to claim 11 is the sheet length measuring device according to any one of claims 3 to 10 , wherein the desired resolution of the sheet length measuring device is R (m), and the light receiving diameter at the light receiving portion is φ ( m), the sheet conveying speed is V (m / s), the pulse frequency in the light projecting unit is f (Hz), the resolution determined by the light receiving diameter φ is _Ra , and the resolution determined by the sheet conveying speed V and the pulse frequency f is R. _{as b}

In which the light receiving diameter φ and the pulse frequency f are set based on the above.

  In the sheet length measuring device, a higher resolution can be obtained as the light receiving diameter φ is set smaller and the pulse frequency f is set larger. A pulse emitting semiconductor laser element can be used as the light projecting section for generating pulsed light, and a light receiving element used as the light receiving section is not uncommon with a light receiving radius of 5 to 50 μm. Therefore, the sheet length measuring device can be easily set to a desired measuring system, although it can be configured with inexpensive and easily available components.

The sheet length measurement according to any one of claims 1 to 11 , wherein the sheet length is measured with respect to a conveyance unit that conveys the sheet along a predetermined conveyance path and a sheet that is conveyed by the conveyance unit. The present invention relates to a sheet distribution line comprising: an apparatus; and a sheet distribution unit that distributes the sheet into a non-defective product and a defective product based on measurement knowledge in the sheet length measuring device.

  In the sheet distribution line, the sheet conveyed by the conveyance unit is distributed into a non-defective product and a defective product by the sheet distribution unit based on the measurement knowledge in the sheet length measuring device.

  Therefore, the measurement of the sheet length and the distribution of the sheets based on the sheet length are performed online, and a sheet whose sheet length is evaluated to be too large or too small in the sheet length measuring device is not shipped.

A thirteenth aspect of the present invention is a cutting means that cuts a belt-like web into a predetermined dimension while rewinding it, and a conveying means that conveys the sheet cut by the cutting means along a predetermined conveying path. And a sheet length measuring device according to any one of claims 1 to 11 , wherein the sheet length is measured for the sheet conveyed by the conveying means. The present invention relates to a sheet cutting line that performs feedback control on the cutting length of the cutting means.

  In the sheet cutting line, since the cutting length in the cutting unit is feedback controlled based on the measurement result of the sheet length in the sheet length measuring unit of the present invention, the web cutting length is too long or too short. Thus, the number of sheets rejected as defective products can be greatly reduced.

The invention according to claim 15, for the sheet to be conveyed along a predetermined transport path, a sheet length measuring method for measuring the sheet length is the length from the leading edge to the trailing edge of the sheet, projecting In the light section, the surface of the sheet is irradiated with pulsed light having a predetermined spread angle and a predetermined pulse period, and light reception disposed on the opposite side of the light projecting section across the sheet conveyance path In the sheet length calculation means comprising a proximity sensor that receives the pulsed light from the light projecting unit in the unit and is adjacent to the upstream side of the light projecting unit and the light receiving unit along the conveyance direction of the sheet, the light is shielded by the sheet seeking shielding time during which the sheet is to shield the pulse light from the pulse interval of the pulse number of the pulse light and the pulsed light, the sheet length on the basis of the conveying speed and the light-shielding time of the sheet A sheet length measuring method and finding.

  According to the sheet length measurement method, sheet measurement with high accuracy is possible.

  As described above, according to the present invention, there are provided a sheet length measuring device, a sheet sorting line, a sheet cutting line, and a sheet length measuring method capable of measuring a sheet length with high accuracy even for a sheet conveyed at high speed. .

1. Embodiment 1
First, the processing line 10 of a lithographic printing plate incorporating the sheet length measuring device of the present invention will be described.

  As shown in FIG. 1, a web delivery machine 14 is disposed on the upstream side of the processing line 10, that is, on the upper right side of FIG. 1, and a long belt-like planographic printing plate web 12 is rolled into the web delivery machine 14. It is loaded in a wound state. The web delivery device 14 continuously delivers the planographic printing plate web 12 to the leveler 16 on the downstream side. The planographic printing plate web 12 reaches the pressure roller 18 after curling is corrected by the leveler 16. The pressure roller 18 presses the long belt-shaped slip sheet 20 sent from the slip sheet feeder 21 to the upper surface of the planographic printing plate web 12, that is, the plate-making surface. The interleaf paper 20 is charged by a charging device (not shown) and electrostatically bonded to the planographic printing plate web 12.

  A notch 22 is disposed on the downstream side of the pressure roller 18. The notch 22 terminates the cutting of the planographic printing plate web 12 when the cutting of the planographic printing plate web 12 is started by the slitter device 24 installed on the downstream side, when the cutting width of the planographic printing plate web 12 is changed, and In this case, a predetermined portion of each side end portion in the width direction of the planographic printing plate web 12 is punched to form a notch. In the slitter device 24, a shearing blade comprising an upper blade and a lower blade is guided by a notch formed by the notch 22 and moves to a predetermined cutting position along the width direction of the web 12, and the planographic printing plate web 12. Change the cutting width.

  Note that a guide mechanism (not shown) is provided adjacent to the downstream side of the slitter device 24 so as to grip the vicinity of the tip of the strip-like ear dust cut off from the web 12 by the slitter device 24 and guide the web cut-out portion to the chopper device. Z.) is provided. The chopper device breaks the web cut portion into fine aluminum scraps that can be recycled. This aluminum scrap is conveyed by the conveyor mechanism 23 and discharged into the collection container 25.

  In the processing line 10, two sets of cutting units 30 constituted by the slitter device 24 and its peripheral members (not shown) are provided. Thereby, setup operations such as replacement of the shearing blade and position adjustment can be performed by the unused cutting unit 30 outside the line, and the line stop time of the processing line 10 is suppressed.

  The lithographic printing plate web 12 cut to a predetermined slit width by the slitter device 24 is counted by the web length measuring device 32, and the web length measuring device 32 counts a count value corresponding to a preset cut length. If it does, it will cut | disconnect linearly along the width direction with the cutter apparatus 34 synchronizing with it. Thereby, a rectangular planographic printing plate 36 having a preset slit width S and cut length L is manufactured. Here, the cut length L can also be referred to as the sheet length L.

  The planographic printing plates 36 are sent to the stacking unit 42 by a plurality of (six in FIG. 1) transport conveyors 60 to 70, and a predetermined number of sheets are stacked in the stacking unit 42 to form a stacking bundle 44. In addition, by supplying a protection sheet 48 such as cardboard or the like at a predetermined timing from the protection sheet supply line 46 to the transport conveyor 68, the cardboard or the like is fed to the upper or lower side or one side of the stack 44 stacked on the stacking unit 42. It becomes possible to arrange | position the protection sheet 48 which becomes.

  A sorting gate (not shown) is installed between the carrying conveyor 62 and the carrying conveyor 64, and the sorting gate is a cut length of the planographic printing plate 36 measured by the sheet length measuring device 100. Is out of the permissible dimensions defined in the quality standards, the lithographic printing plate 36 is distributed from the conveyor 62 to the line-out conveyor 72. As a result, the transport conveyor 72 transports the planographic printing plate 36 whose cut length deviates from the quality standard obliquely downward, and throws it into the collection container 76 from its downstream end. The sorting gate swings to one of a first guide position for guiding the planographic printing plate 36 to the transport conveyor 64 and a second guide position for guiding the planographic printing plate 36 to the transport conveyor 72.

  On the other hand, the stacked bundle 44 composed of the planographic printing plates 36 whose cut length satisfies the quality standard is conveyed to a predetermined transshipment position by a plurality of conveyors 50, and the pallet is moved from the conveyor 50 by the transshipment device 52 at this transshipment position. Transshipment onto 54. The pallet 54 on which the bundled bundles 44 are loaded is sent to the packaging process by the automatic conveying device 56, packaged by exterior paper such as kraft paper, and further stored in a storage box such as a cardboard box as necessary. Or on a pallet for shipping.

  Hereinafter, the sheet length measuring apparatus 100 will be described.

  As shown in FIGS. 2 and 3, the transport conveyor 62 provided with the sheet length measuring device 100 is composed of two belt conveyors 62A and 62B arranged in parallel along the transport direction indicated by the arrow a. ing.

  The sheet length measuring apparatus 100 includes a light projecting / receiving unit 102 provided at the downstream end of the transport conveyor 62 along the transport direction a, and a proximity sensor 104 adjacent to the upstream side of the light projecting / receiving unit 102 along the transport direction a. With. The light projecting / receiving unit 102 and the proximity sensor 104 are both provided between the belt conveyor 62A and the belt conveyor 62B.

  The light projecting / receiving unit 102 is positioned below the transport path of the planographic printing plate 36 and receives the pulsed light from the light projecting head 101 that emits pulsed light and the light projecting head 101 that is positioned above the transport path. The light receiving head 103 is configured to be configured. The light projecting head 101 and the light receiving head 103 correspond to the light projecting unit and the light receiving unit in the present invention, respectively. The light projecting head 101 includes an optical fiber 101B and a collimator unit 101A provided on the optical axis thereof. The light receiving head 103 includes a collimator unit 103A into which the pulsed light projected from the light projecting head 101 is incident. The optical fiber 103B guides the pulsed light incident on the collimator unit 103A to a light receiving amplifier 121 described later.

  An optical fiber 105 is connected to a laser light source 108 that generates pulsed light. A fiber coupler 110 is interposed in the middle of the optical fiber 105, and an optical fiber 101B constituting the light projecting head 101 branches off from the fiber coupler 110.

  A pulse generator 106 is connected to the laser light source 108.

  The pulse generator 106 generates a high frequency pulse trigger, and the laser light source 108 receives the high frequency pulse trigger generated by the pulse generator 106 and generates high output pulse light. The pulsed light generated by the laser light source 108 is introduced into the optical fiber 105, a part thereof is introduced into the optical fiber 101B via the fiber coupler 110, and is irradiated from the collimator unit 101A with a predetermined spread angle. The remainder of the pulsed light is introduced into the light receiving amplifier 120 via the fiber coupler 110 and the optical fiber 105, converted into a pulse signal by the light receiving amplifier 120, and input to the computer 150. Instead of introducing the pulsed light from the laser light source 108 into the light receiving amplifier 120, converting it into a pulse signal and introducing it into the computer 105, a high frequency pulse trigger generated by the pulse generator 106 as shown in FIG. You may enter directly into.

  When the pulsed light is introduced from the light receiving head 103, the light receiving amplifier 121 connected to the light receiving head 103 converts the pulsed light into an electric pulse signal and introduces it into the computer 150.

  The light receiving amplifiers 120 and 121 include a light receiving element, a waveform shaper, and an operational amplifier.

  The computer 150 corresponds to a sheet length calculating means in the present invention, and a desktop computer 140 for inputting a signal from the proximity sensor 104 is connected in addition to the light receiving amplifiers 120 and 121. The proximity sensor 104 is connected to the desktop computer 140 via the pulse counter board 130.

  Hereinafter, the operation of the sheet length measuring apparatus 100 will be described.

  When the lithographic printing plate 36 is conveyed on the conveyor 62 and the proximity sensor 104 detects the lithographic printing plate 36, the proximity sensor 104 sends a signal indicating that the lithographic printing plate 36 has been detected via the pulse counter substrate 130 to the desktop type. Input to computer 140. When the signal is input to the desktop computer 140, the desktop computer 140 instructs the computer 150 to count the number of pulses.

  When the command is input to the computer 150, the computer 150 starts counting pulses in the light receiving amplifier 120 and the light receiving amplifier 121. Since the pulsed light is directly incident on the light receiving amplifier 120 from the laser light source 108, as shown in FIG. 5A, the pulsed light is supplied during the time t = 0 to Δt during which the pulse is counted. To detect. Here, t = 0 is the time when the pulse count is started, and t = Δt is the time when the pulse count is finished.

  On the other hand, in the light receiving amplifier 121 that detects the pulsed light received by the light receiving head 103, the pulsed light projected from the light projecting head 101 to the light receiving head 103 is lithographic printing plate 36 as shown by the solid line in FIG. Until the light is shielded, pulsed light having the same cycle and phase as those detected by the light receiving amplifier 120 is detected. However, while the planographic printing plate 36 is transported along the transport direction a and passes between the light projecting head 101 and the light receiving head 103, the pulsed light projected from the light projecting head 101 is blocked. As indicated by the broken line in FIG. 5B, the pulsed light is not detected. When the planographic printing plate 36 finishes passing between the light projecting head 101 and the light receiving head 103, the pulsed light projected from the light projecting head 101 enters the light receiving head 103 again. As shown by the solid line in FIG. 5, the pulsed light is again detected by the light receiving amplifier 121.

Therefore, assuming that the count value in the light receiving amplifier 120 is P1 and the count value in the light receiving amplifier 121 is P2, P1 is the total number of pulses generated by the laser light source 108 from time t = 0 to t = Δt, and P2 Is the total number of pulses of the pulsed light that is not shielded by the planographic printing plate 36. When the transport speed of the planographic printing plate 36 is V (m / s) and the oscillation period of the pulsed light generated by the laser light source 108 is T _PG (s), the displacement amount X ( t) (m)
X (t) = V × T _PG
become.

  The sheet length L (m), which is the length of the planographic printing plate 36 in the conveyance direction, may be obtained by adding the displacement amount X (t) to the total number of shielded pulses.

become that way.

In the sheet measuring apparatus 100, since the sheet length L of the lithographic printing plate 36 is obtained based on the number of pulses shielded by the lithographic printing plate 36, the resolution R (m) is the frequency of the pulsed light generated by the laser light source 108. It is determined by f = 1 / _TPG and the light receiving diameter φ (m) in the light receiving head 103. In other words, when the resolution determined by the light receiving diameter φ is R _a and the resolution determined by the sheet conveyance speed V and the pulse frequency f is R _b ,

As shown by the figure, the larger one of the resolutions _Ra and _Rb is obtained.

  Accordingly, the sheet length measuring device 100 is provided by means such as increasing the frequency of the pulsed light or setting the pulsed light spread angle to be small in the light projecting head 101 and the light receiving head 103 to reduce the light receiving diameter φ. Can achieve a high resolution of 10 to several tens of μm.

  Further, since it is not necessary to use any special components such as the laser light source 108, the pulse generator 106, the light receiving amplifiers 120 and 121, and the pulse counter substrate 130, the sheet length measuring device 100 is configured at a very low cost. it can.

2. Embodiment 2
Another example of the sheet length measuring device used in the processing line 10 will be described below.

  As shown in FIG. 6, the sheet length measuring apparatus 200 according to the second embodiment is provided with a light projecting / receiving unit 202 that is a second light projecting / receiving unit upstream of the light projecting / receiving unit 102 with respect to the conveyance direction a. . Note that the proximity sensor 104 is provided adjacent to the upstream side of the light projecting / receiving unit 102 as in the sheet length measuring apparatus of the first embodiment. The distance D between the light projecting / receiving unit 102 and the light projecting / receiving unit 202 may be shorter or longer than the sheet length L of the planographic printing plate 36, but the difference from the sheet length L is preferably small. As shown in FIG. 7, the light projecting / receiving unit 202 includes a light projecting head 201 positioned below the transport path of the planographic printing plate 36 and a light receiving head 203 positioned above the transport path.

  As shown in FIG. 7, the light projecting head 201 includes an optical fiber 201B and a collimator unit 201A that is provided on the optical axis of the optical fiber 201B and emits pulsed light introduced from the optical fiber 201B at a predetermined spread angle. It has become.

  An optical fiber 105 is connected to the laser light source 108, and a fiber coupler 110 and a fiber coupler 111 are provided in the middle of the optical fiber 105. The optical fiber 105 branches into an optical fiber 105A and an optical fiber 105B in the fiber coupler 110. A fiber coupler 111 is provided in the middle of the optical fiber 105 </ b> A. The fiber coupler 111 branches into an optical fiber 101 </ b> B constituting the light projecting head 101 and an optical fiber 201 </ b> B constituting the light projecting head 201. On the other hand, the optical fiber 105B is connected to the light receiving amplifier 120.

  The pulsed light emitted from the laser light source 108 is branched by the fiber coupler 110, a part of which is introduced into the optical fiber 105A, and the rest enters the light receiving amplifier 120 through the optical fiber 105B. The pulsed light introduced into the optical fiber 105A is emitted from the collimator unit 101A of the projection head 101 through the optical fiber 101B, and the remainder is emitted from the collimator unit 201A of the projection head 201 through the optical fiber 201B. The

  The light receiving head 203 includes a collimator unit 203A that receives pulsed light from the light projecting head 201, and an optical fiber 203B that guides the pulsed light incident on the collimator unit 203A to the light receiving amplifier 220. The light receiving amplifier 220 has the same configuration as the light receiving amplifiers 120 and 121, and is connected to the computer 150 in the same manner.

  Except for these points, the sheet length measuring apparatus 200 has the same configuration as the sheet length measuring apparatus 100 of the first embodiment.

  Hereinafter, the operation of the sheet length measuring apparatus 200 will be described.

  Also in the sheet length measuring apparatus 300, when the proximity sensor 104 detects the planographic printing plate 36, the proximity sensor 104 inputs a signal indicating that the planographic printing plate 36 has been detected to the desktop computer 140 via the pulse counter board 130. To do. When the signal is input to the desktop computer 140, the desktop computer 140 instructs the computer 150 to count the number of pulses.

  When the command is input to the computer 150, the computer 150 starts counting pulses in the light receiving amplifier 120 and the light receiving amplifier 121. Since the pulsed light is directly incident on the light receiving amplifier 120 from the laser light source 108, as shown in FIG. 8A, the pulsed light is supplied during the time t = 0 to Δt during which the pulse is counted. To detect. Here, t = 0 is the time when the pulse count is started, and t = Δt is the time when the pulse count is finished.

  Therefore, as indicated by A in FIGS. 8 and 9, the light receiving amplifier 120 detects the pulsed light during the time t = 0 to Δt.

  On the other hand, in the light receiving amplifier 121, as shown by B in FIGS. 8 and 9, the light receiving amplifier 120 until the pulse light projected from the light projecting head 101 to the light receiving head 103 is blocked by the planographic printing plate 36. Pulse light having the same cycle and phase as detected is detected. However, when the lithographic printing plate 36 is conveyed at time t = t2 and the pulse light is shielded, the pulse light is not detected. 8 and 9, the solid line indicates that pulse light is detected, and the broken line indicates that pulse light is not detected.

  In the light projecting / receiving unit 202, the lithographic printing plate 36 initially passes through the light projecting / receiving unit 202. Therefore, the pulse light from the light projecting head 201 is blocked by the planographic printing plate 36 and does not reach the light receiving head 203. . Therefore, as indicated by C in FIGS. 8 and 9, no pulsed light is detected in the light receiving amplifier 220. When the lithographic printing plate 36 is conveyed and passes through the light projecting / receiving unit 202 at time t = t3, the pulsed light from the light projecting head 201 reaches the light receiving head 203.

  Here, when the distance D between the light projecting / receiving unit 102 and the light projecting / receiving unit 202 is smaller than the sheet length L of the planographic printing plate 36, the light projecting / receiving unit 102 at time t = t2 as shown in FIG. The pulsed light is shielded, and the light projecting / receiving unit 202 ends the shielding at time t = t3 after time t = t2.

  Therefore, at time t = t2 to t3, the pulse light is shielded in both the light projecting and receiving units 102 and 202, and during that time the lithographic printing plate 36 advances by ΔL = LD, so that time t = 0 When the number of pulsed light received by the light receiving amplifier 120 during Δt is P1, the number of pulsed light received by the light receiving amplifier 121 is P2, and the number of pulsed light received by the light receiving amplifier 220 is P3, the planographic printing plate 36 is , ΔL = LD, the number of pulses ΔP23 while traveling by ΔD is given by ΔP23 = P1-P2-P3.

Therefore, if the transport speed of the planographic printing plate 36 is V (m) and the pulse period is T _PG (s), ΔL (m) is expressed by the following formula:
ΔL = VT _PG (P1-P2-P3)
Given in.

Therefore, the sheet length L is given by the following formula:
L = VT _PG (P1-P2-P3) + D
Given in.

  On the other hand, when the distance D is larger than the sheet length L, as shown in FIG. 9, the time t = t2 when the light projecting / receiving unit 102 shields the pulsed light is the time t = t2 when the light projecting / receiving unit 202 ends the light shielding. Later than t3.

  Therefore, at time t = t3 to t2, the pulse light is not shielded in any of the light projecting / receiving units 102 and 202, and during that time the lithographic printing plate 36 advances by ΔL = D−L. Lithographic printing, where P1 is the number of pulsed light received by the light receiving amplifier 120 between 0 and Δt, P2 is the number of pulsed light received by the light receiving amplifier 121, and P3 is the number of pulsed light received by the light receiving amplifier 220 In the plate 36, the number of pulses ΔP23 while traveling by ΔL = D−L is given by ΔP23 = P2 + P3-P1.

Therefore, if the transport speed of the planographic printing plate 36 is V (m) and the pulse period is T _PG (s), ΔL (m) is expressed by the following formula:
ΔL = VT _PG (P2 + P3-P1)
The sheet length L is given by
L = D−ΔL = D−VT _PG (P2 + P3-P1)
Given in.

  In the sheet length measuring apparatus 200, since the pulse light is once shielded by the light projecting / receiving unit 102 and it is not necessary to continue the sheet length measurement until the light shielding is released, the sheet length can be measured with a shorter pulse capturing time. Accordingly, in addition to the features of the sheet length measuring apparatus according to the first embodiment, the sheet length measuring apparatus 200 can measure the sheet length in a shorter time and can transport even when the transport speed V of the planographic printing plate 36 varies. It has the feature that it is not easily affected by fluctuations in the speed V.

3. Embodiment 3
Still another example of the sheet length measuring device used in the processing line 10 will be described below.

The conveyor 62 provided with the sheet length measuring device 300 according to the third embodiment includes a belt conveyor 62B located at the center and belt conveyors 62A and 62C disposed on both sides thereof.
In the sheet length measuring apparatus 300, as shown in FIGS. 10 and 11, the light projecting / receiving unit 102 and the light projecting / receiving unit 202 located on the upstream side of the light projecting / receiving unit 102 with respect to the transport direction a are the belt conveyor 62B. It is arranged between the belt conveyor 62C. The light projecting / receiving unit 302 that measures the inclination θ of the planographic printing plate 36 with respect to the transport direction a is a direction perpendicular to the transport direction a with respect to the light projecting / receiving unit 102 and between the belt conveyor 62A and the belt conveyor 62B. It is arranged. The distance between the light projecting / receiving unit 202 and the light projecting / receiving unit 102 is D1, and the distance between the light projecting / receiving unit 302 and the light projecting / receiving unit 102 is D2. The proximity sensor 104 is provided on the upstream side of the light projecting / receiving units 102 and 302 and on the downstream side of the light projecting / receiving unit 202 with respect to the transport direction a and above the belt conveyor 62B.

  The light projecting / receiving unit 302 is provided on the lower side of the transport path of the planographic printing plate 36 and on the upper side of the transport path, and the light receiving head 303 on which the pulsed light from the light projecting head 301 enters. Consists of. As shown in FIG. 11, the light projecting head 301 is provided on the optical axis of the optical fiber 301B at the tip of the optical fiber 301B and the optical fiber 301B, and projects the light from the optical fiber 301B at a predetermined spread angle. And a collimator unit 301A. Similarly, the light receiving head 303 includes a collimator unit 303A into which the pulsed light projected from the light projecting head 301 enters, and an optical fiber 303B connected to the collimator unit 303A.

  As shown in FIG. 11, the light projecting head 301 also guides pulsed light from the laser light source 108 through the optical fiber 105 in the same manner as the light projecting head 101 and the light projecting head 201.

  In the middle of the optical fiber 105, fiber couplers 110, 111, and 112 are provided.

  The optical fiber 105 branches into an optical fiber 105A and an optical fiber 105B in the fiber coupler 110. In the fiber coupler 111, the optical fiber 101B constituting a part of the projection head 101 branches from the optical fiber 105A, and the optical fiber 201B constituting the part of the projection head 201 and the projection head 301 in the fiber coupler 112 are branched. Branches to an optical fiber 301B constituting a part.

  The pulsed light emitted from the laser light source 108 is branched by the fiber coupler 110, a part of which is introduced into the optical fiber 105A, and the rest enters the light receiving amplifier 120 through the optical fiber 105B. A part of the pulse light introduced into the optical fiber 105 </ b> A is introduced into the light projecting head 101 through the fiber coupler 111, and the rest is introduced into the light projecting head 201 and the light projecting head 301 through the fiber coupler 112. Is done.

  In the light receiving head 303, the pulsed light entering the collimator 303A is received by the light receiving amplifier 320 through the optical fiber 303B. The light receiving amplifier 320 has the same configuration as the light receiving amplifiers 120, 121, and 220, and is connected to the computer 150 in the same manner as these light receiving amplifiers.

  The sheet length measuring apparatus 300 further includes an encoder 310 that measures the conveyance speed V in the conveyance conveyor 62. The signal from the encoder 310 is input to the computer 150 through the desktop computer 140.

  Except for these points, the sheet length measuring apparatus 300 has the same configuration as the sheet length measuring apparatus 200 of the second embodiment.

  Hereinafter, the operation of the sheet length measuring apparatus 300 will be described.

  Also in the sheet length measuring apparatus 300, when the proximity sensor 104 detects the planographic printing plate 36, the proximity sensor 104 inputs a signal indicating that the planographic printing plate 36 has been detected to the desktop computer 140 via the pulse counter board 130. To do. When the signal is input to the desktop computer 140, the desktop computer 140 instructs the computer 150 to count the number of pulses.

  When the command is input to the computer 150, the computer 150 starts counting pulses in the light receiving amplifier 120 and the light receiving amplifier 121. Since the pulsed light is directly incident on the light receiving amplifier 120 from the laser light source 108, as shown in A in FIG. 12, the pulsed light is applied during the time t = 0 to Δt during which the pulse is counted. To detect. Here, t = 0 is the time when the pulse count is started, and t = Δt is the time when the pulse count is finished.

  Therefore, as indicated by A in FIGS. 12 and 13, the light receiving amplifier 120 detects the pulsed light during the time t = 0 to Δt.

  On the other hand, in the light receiving amplifier 121, until the pulsed light projected from the light projecting head 101 to the light receiving head 103 is blocked by the planographic printing plate 36, the light receiving amplifier 120 as shown in B in FIGS. Pulse light having the same cycle and phase as detected is detected. However, when the pulse light is shielded by the planographic printing plate 36 at t = t2, no pulse is detected as shown in FIG. . 8 and 9, the solid line indicates that pulse light is detected, and the broken line indicates that pulse light is not detected.

  In the light projecting / receiving unit 202, the lithographic printing plate 36 initially passes through the light projecting / receiving unit 202. Therefore, the pulse light from the light projecting head 201 is blocked by the planographic printing plate 36 and does not reach the light receiving head 203. . Accordingly, as indicated by C in FIGS. 12 and 13, no pulsed light is detected in the light receiving amplifier 220. Then, when the planographic printing plate 36 finishes passing through the light projecting / receiving unit 202 at time t = t3, the pulsed light from the light projecting head 201 reaches the light receiving head 203.

Therefore, in the sheet length measuring apparatus 300, the sheet length L ′ along the conveyance direction a is expressed by the following formula as described in the second embodiment:
L ′ = VT _PG (P1-P2-P3) + D (D <L), or
L ′ = D−VT _PG (P2 + P3−P1) (D> L)
Is required.

  Here, as shown in FIG. 10, in the sheet length measuring device 300, the planographic printing plate 36 is conveyed in a state inclined by an angle θ with respect to the conveyance direction a. Light is shielded at time t = t4 later than time t = t2 when the light projecting / receiving unit 202 is shielded from light.

If the number of pulses detected by the light receiving amplifier 320 from the time t = 0 to the time when the pulse light is blocked by the light projecting and receiving unit 302 is P4, the feed length W of the planographic printing plate 36 corresponding to ΔP24 = P2−P4. Is the following formula:
W = (P4-P2) VT _PG
It is represented by Here, since the inclination θ is normally considered to be small, θ, D2, and W are expressed by the following equations:
θ = tan ⁻¹ (W / D2) ≈cos−1 (W / D2)
It is represented by

Therefore,
cos θ = W / D2 = (P4-P2) VT _PG / D2
It is.

Here, the true sheet length L is
L = L'cosθ
Therefore, substituting the above equation, L = [VT _PG (P1-P2-P3) + D] × (P4-P2) VT _PG / D2 (D <L)
_{L = [D-VT PG (} P2 + P3-P1)] × (P4-P2) VT PG / D2 (D> L)
Is required.

  In the sheet length measuring device 300, the conveyance speed of the lithographic printing plate 36 is measured by the encoder 310.

Thus, the average value of the conveyance speed V (t) at time t = 0 to Δt may be obtained, and this may be used as the conveyance speed V to obtain the sheet length L or the like.

Further, as shown in FIG. 14, the value of the encoder 310 is continuously read at the pulse oscillation timing in the pulse generator 106, and the read value of the encoder 310 when the kth pulse is generated corresponds to the kth pulse. it may transport speed V of the planographic printing plate 36 (t _k) to.

  At this time, the sheet length L ′ along the conveyance direction a is expressed by the following formula:

または、

Or

Is required.

  The feed length W of the planographic printing plate 36 is

(X (t) indicates the transport distance of the lithographic printing plate 36 per pulse)
Is required.

  Therefore, cos θ is given by

Is required.

  Therefore, the true sheet length L is given by

Is required.

  The sheet measuring apparatus 300 according to the third embodiment can accurately obtain the sheet length L of the lithographic printing plate 36 even when the lithographic printing plate 36 is conveyed in an inclined state. Also, errors due to fluctuations in the conveyance speed can be minimized.

  As described above, in the first to third embodiments, the sheet length measuring apparatus that performs pulse measurement by generating pulsed light in the laser light source 108 has been described. However, in the sheet length measuring apparatuses 100 to 300, continuous light is generated from the laser light source 108. Even if the continuous light is received by the on / off sensor in the light receiving amplifiers 120, 121, 220, and 320, the sheet length can be measured with high resolution.

FIG. 1 is a perspective view illustrating an overall configuration of a processing apparatus for a lithographic printing plate web in which the sheet length measuring apparatus according to the first to third embodiments is used. FIG. 2 is a plan view illustrating the outline of the configuration of the sheet length measuring apparatus according to the first embodiment. FIG. 3 is a perspective view illustrating the outline of the configuration of the sheet length measuring apparatus according to the first embodiment. FIG. 4 is a perspective view illustrating a schematic configuration of another example of the sheet length measuring apparatus according to the first embodiment. FIG. 5 is an explanatory diagram illustrating pulses detected by the sheet length measuring apparatus according to the first embodiment. FIG. 6 is a plan view schematically illustrating the configuration of the sheet length measuring apparatus according to the second embodiment. FIG. 7 is a perspective view illustrating the outline of the configuration of the sheet length measuring apparatus according to the second embodiment. FIG. 8 is an explanatory diagram illustrating pulses detected when the distance D between the light projecting and receiving units on the upstream side and the downstream side is shorter than the sheet length L in the sheet length measuring apparatus according to the second embodiment. FIG. 9 is an explanatory diagram showing pulses detected when the distance D between the light projecting and receiving units on the upstream side and the downstream side is longer than the sheet length L in the sheet length measuring apparatus according to the second embodiment. FIG. 10 is a plan view schematically illustrating the configuration of the sheet length measuring apparatus according to the third embodiment. FIG. 11 is a perspective view illustrating a schematic configuration of a sheet length measuring apparatus according to the third embodiment. FIG. 12 is an explanatory diagram illustrating pulses detected when the distance D between the light projecting and receiving units on the upstream side and the downstream side is shorter than the sheet length L in the sheet length measuring apparatus according to the third embodiment. FIG. 13 is an explanatory diagram showing pulses detected when the distance D between the upstream and downstream light projecting / receiving portions is longer than the sheet length L in the sheet length measuring apparatus according to the third embodiment. FIG. 14 illustrates a planographic printing plate measured by an encoder and a pulse detected when the distance D between the upstream and downstream light emitting / receiving portions is shorter than the sheet length L in the sheet length measuring apparatus according to the third embodiment. It is explanatory drawing which shows the relationship with speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Sheet length measuring apparatus 102 Light emitting / receiving part 104 Proximity sensor 106 Pulse generator 108 Laser light source 120 Light receiving amplifier 121 Light receiving amplifier 130 Pulse counter board 140 Desktop computer 150 Computer 200 Sheet length measuring apparatus 202 Light emitting / receiving part 220 Light receiving amplifier 300 Sheet length Measuring device 302 Light emitting / receiving unit 320

Claims (14)

For a sheet conveyed along a predetermined conveyance path, a sheet length measuring device that measures a sheet length that is a length from a front edge to a rear edge of the sheet,
A light projecting unit that irradiates the surface of the sheet with pulsed light having a predetermined divergence angle and a predetermined pulse period ;
A light receiving unit disposed on the opposite side of the light projecting unit across the conveyance path of the sheet, and receiving a pulsed light from the light projecting unit;
The sheet includes a proximity sensor adjacent to the upstream side of the light projecting unit and the light receiving unit along the conveyance direction of the sheet, and the sheet includes the number of pulses of the pulsed light shielded by the sheet and the pulse interval of the pulsed light. A sheet length measuring device comprising: a sheet length calculating unit that obtains a light shielding time during which the pulsed light is shielded, and obtains the sheet length based on the light shielding time and the sheet conveyance speed. The light projecting unit includes an optical fiber that guides inspection light from a light source, and a collimator unit that is provided on the optical axis of the optical fiber and sets a spread angle of pulsed light emitted from the fiber to a predetermined angle. The sheet length according to claim 1, wherein the light receiving unit includes a collimator unit disposed on an optical axis of the light projecting unit, and an optical fiber that guides the inspection light converged by the collimator unit to the light receiving element. Measuring device. A set of light projecting / receiving units composed of the light projecting unit and the light receiving unit,
The sheet length calculation means includes a pulse number P1 generated by the light projecting unit during a predetermined measurement time, a pulse number P2 actually received by the light receiving unit, and a pulse conveying speed V (m / s). And the pulse period T _PG (s), the following formula:

To obtain the sheet length L
The sheet length measuring apparatus according to claim 1 . Two of the light projecting and receiving units are disposed along the sheet conveying direction, and generate pulses in synchronization with the light projecting unit.
The sheet length calculation means includes a distance D between the two light projecting / receiving units, a pulse number P1 generated in the light projecting unit included in the light projecting / receiving unit during a predetermined measurement time, and a downstream along the sheet conveying direction. The number of pulses P2 detected in the light receiving section disposed on the side, the number of pulses P3 detected in the light receiving section disposed on the upstream side with respect to the sheet conveying direction, and the pulses in these light projecting and receiving sections Based on the cycle _TPG and the sheet conveyance speed V, the following formula:

Is used to obtain the sheet length L
The sheet length measuring apparatus according to claim 1 . The sheet length measuring apparatus according to claim 4 , wherein a distance D between the two light projecting and receiving units can be changed according to a sheet length L. Three or more of the light projecting and receiving parts are disposed along the conveyance direction of the sheet,
The sheet length measuring device according to claim 4 , wherein the sheet length calculating unit performs sheet length measurement by selecting two of the light projecting and receiving units according to the sheet length L. While having a conveyance speed measuring means for measuring the conveyance speed of the sheet,
The sheet length calculation means, according to any one of claims 1 to 6 for obtaining the number of pulses of the pulse light received, a sheet length based on the transport speed measured by the transport speed measuring means emitting and receiving portion Sheet length measuring device. The light projecting / receiving unit is arranged in one or more sets along the sheet conveyance direction,
The sheet length calculation means sets the conveyance speed measured by the conveyance speed measurement means to V (t), the sheet length measurement start time as t = 0, the sheet length measurement end time as t = Δt, and the conveyance speed V (t). When the average value is an average transport speed V _ave , the following formula:

Average calculated transport speed V _ave, the sheet length measuring apparatus according to claim 7 for determining the sheet length on the basis of the average transport speed V _ave obtained based on. The conveyance speed measuring unit measures a sheet conveyance speed V [(k / P1) · Δt] every time the light emitting unit generates the k-th pulse, and inputs the measured value to the sheet length calculation unit.
The sheet length calculating means has the following formula:

The sheet length measuring device according to claim 4 , wherein the sheet length L is obtained based on the above. A plurality of the light projecting and receiving units are provided along a direction orthogonal to the sheet conveying direction,
10. The sheet length calculation unit according to claim 1 , wherein the sheet length calculation unit corrects the sheet length by obtaining an inclination θ with respect to the conveyance direction of the sheet based on a difference in light shielding timing between the light projecting and receiving units. Sheet length measuring device. The desired resolution of the sheet length measuring device is R (m), the light receiving diameter at the light receiving unit is φ (m), the sheet conveyance speed is V (m / s), the pulse frequency at the light projecting unit is f (Hz), The resolution determined by the diameter φ is R _a , and the resolution determined by the sheet conveying speed V and the pulse frequency f is R _b ,

The sheet length measuring device according to claim 3 , wherein the light receiving diameter φ and the pulse frequency f are set based on Conveying means for conveying the sheet along a predetermined conveying path;
The sheet length measuring device according to any one of claims 1 to 11 , wherein a sheet length is measured for a sheet conveyed by the conveying unit.
A sheet distribution line comprising sheet distribution means for distributing the sheet into a non-defective product and a defective product based on measurement knowledge in the sheet length measuring device. A cutting means for cutting the web into a predetermined dimension while rewinding the belt-shaped web;
Conveying means for conveying the sheet cut by the cutting means along a predetermined conveying path;
The sheet length measuring device according to any one of claims 1 to 11 , which measures a sheet length for a sheet conveyed by the conveying means.
A sheet cutting line that performs feedback control of a cutting length in the cutting unit based on a sheet length measurement result in the sheet length measuring apparatus. For a sheet conveyed along a predetermined conveyance path, a sheet length measurement method for measuring a sheet length that is a length from a front edge to a rear edge of the sheet,
In the light projecting portion, the surface of the sheet is irradiated with pulsed light having a predetermined divergence angle and a predetermined pulse period,
Receiving the pulsed light from the light projecting unit at the light receiving unit disposed on the opposite side of the light projecting unit across the sheet conveyance path,
In a sheet length calculation unit including a proximity sensor adjacent to the upstream side of the light projecting unit and the light receiving unit along the conveyance direction of the sheet, the number of pulses of the pulsed light shielded by the sheet and the pulse interval of the pulsed light A sheet length measurement method comprising: obtaining a light shielding time during which the sheet shields pulsed light, and obtaining the sheet length based on the sheet conveyance speed and the light shielding time .

Images