JPH02136989A - Paper measuring instrument - Google Patents

Abstract

PURPOSE:To accurately detect the fine shape of a side end of paper and its quantity by irradiating the flank of stacked sheets of paper with only the horizontally linear polarized component of laser light vertically, and detecting only the circular polarized component of its reflected light and measuring the light- dark variation of the reflected light. CONSTITUTION:The flank of the longitudinally stacked sheets of paper 3 on a straight moving table 11 is irradiated with the horizontally linear polarized component of the laser light and this straight moving table 11 is put in straight moving motion by a driving mechanism 12 to scan the laser light the flank of the paper stacked on this table from end to end. Only the circular polarized component of the light reflected by the side end part of paper 3 is converged by a convex lens 15 and focused on a photodetector 5, which measures the light and shade of the reflected light to measure the quantity of paper and the shape of the side end part of the paper. Consequently, the quantity of the paper and the shape of the side end of the paper are accurately detected by utilizing the laser light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper measuring device that uses laser light to accurately detect the number of sheets of paper and the shape of the side edges of the paper.

[Conventional technology]

BACKGROUND ART Conventionally, methods used in banknote counters and the like have often been used to measure the number of sheets of paper. In this method, the central part of the stacked banknotes is fixed, the edges are separated with metal pieces, light is irradiated there, and the number of banknotes is counted by detecting the flicker of the light with a photoelectric element. It is something.

However, this method cannot be used for paper thinner than banknotes. This is because the paper will be damaged by being handled by the metal pieces. On the other hand, even if the paper is thicker than banknotes, the paper will break when the metal pieces are handled, making it impossible to count satisfactorily.

On the other hand, in recent years, in order to solve the drawbacks of these conventional contact paper sheet counting methods, methods have been adopted that count the number of paper sheets only by optical methods without making any physical contact with the paper. . An example of this is disclosed in Japanese Patent Publication No. 57-10475, which will be explained with reference to FIG.

A printed workpiece 3, such as a package of a paper carton that has been printed, folded, and glued by a box-making machine, or a signature of a printed matter, with its spine facing down, is placed vertically on a pedestal 4 having a slit. I'll put it on. Light from a light bulb 1 is irradiated onto the bottom surface of a printed workpiece 3 through a slit. The reflected light is received by a photoelectric conversion element 5 such as a phototransistor, and the number of the workpieces 3 is counted by a digital counter IO. In this invention, the printed products, which were difficult to count due to the difficulty of reflecting the irradiated light, are arranged in a vertical direction, and the irradiation angle of the light source is changed, and the reflected light is captured by a photoelectric conversion element and counted. The optimum irradiation angle was determined as follows depending on the density of the printed workpiece.

Reflection density 0.8~1.0 θ: 42°1.0~
1.2 θ: 30' Glossy object θ: 45° [Problem to be solved by the invention] In counting using a conventional optical paper counting device, as shown in FIG. 6, stacked papers 3a, 3b, 3c, 3d.

The side surface of the paper is irradiated with light from a direction forming an irradiation angle θ (30° to 45° in the above patent publication) with respect to the vertical direction of the side surface of the paper 3e. Then, a photoelectric element is installed vertically to the side of the paper, with a bright area illuminated by light and a dark area (the surface area marked with diagonal lines in Figure 6) where no light hits due to the shadow of the paper. The number of sheets of paper is counted based on the change in brightness.

However, if the side surface of the paper is angular in cross section, it is possible to count the number of sheets using a conventional sheet counter, but if the side surface of the paper is circular, the number of sheets of paper can be counted. Since the shadow of the side edge was not clearly generated, it was difficult to actually measure it.

Furthermore, if the arrangement of the sides of the paper is irregular as shown in Figure 7, and the side edges of papers 3g and 3h are in the shadow of paper 3f, the diagonally lined surface in the figure As shown in the section, the side edges of these papers were not illuminated and as a result these papers were not counted.

Also, as shown in FIG. 8, the paper 31 is paper 3 i, 3 j, 3
In the case of paper 31 covering the side edges of the other three sheets, conventional sheet counters only detect the bright areas, and detect an abnormal condition where paper 31 covers the side edges of the other three sheets. It was impossible to do so.

On the other hand, as described above, the conventional measurement of the number of sheets of paper is performed by irradiating light obliquely onto the side of the paper. However, it is impossible to measure the shape of the side edges of each sheet of paper using this method, so conventionally there has been no device that can measure the shape of the side edges of paper or the thickness of paper. Ta.

[Means for solving problems]

The present invention includes a light source that generates a laser beam, a polarizing beam splitter, a quarter wavelength correction component, a convex lens, and a photodetector, the laser beam being generated from the light source, the polarizing beam splitter, the quarter wavelength correction component, and a photodetector. The light source and the polarizing beam splitter are arranged so that the laser beam that has passed through the wavelength correction component and the convex lens is irradiated onto the side edge of the stacked papers, and the axes of the incident light and the reflected light at the side edge are aligned. , said one-fourth
A wavelength correction component and the convex lens are arranged, the polarizing beam splitter is arranged so that the reflected light is reflected in a direction perpendicular to the axis, and the light reflected by the polarizing beam splitter is detected by the optical detection. The problems of the prior art are solved by a paper measuring device characterized in that the photodetector is arranged so that the light is incident on a container, and a mechanism is provided to relatively move the incident light and the side edge of the paper. This is what I did.

Furthermore, the present invention includes a light source that generates a laser beam, a holographic plate, a convex lens, and a photodetector, and the laser beam that has passed through the light source, the holographic plate, and the convex lens is applied to a side edge of the stacked paper. is configured so that the light reflected by the paper passes through the holographic plate and reaches the photodetector, and the relative positions of the side edges of the paper and the laser beam incident on the side edges are determined. The paper measuring device is characterized by being equipped with a changing mechanism, and the paper measuring device is further made smaller and lighter.

[Effect]

The paper measurement device of the present invention vertically irradiates only the horizontally linearly polarized component of laser light onto the side surface of stacked papers, detects only the circularly polarized component of the reflected light, and detects changes in the brightness and darkness of the reflected light. This detects the number of sheets of paper and the condition of the side edges of the paper.

The laser beam is irradiated perpendicularly to the side surface of the stacked sheets of paper that is the object to be measured, but when the irradiated surface, that is, the side edge surface of the paper, is perpendicular to the incident light, the reflected light is maximum, and the irradiated surface is The reflected light becomes weaker when it is tilted relative to the incident light. For this reason, the intensity of the reflected light changes depending on the shape of the side edge of the paper, so by measuring this, it is possible to accurately detect the minute shape of the side edge of the paper and the number of sheets of paper. I can do it.

In this way, the paper measuring device of the present invention is different from the conventional paper measuring device, which irradiates light obliquely to generate shadows, because it detects the amount of reflection depending on the amount of inclination of the reflective surface. It is possible to accurately measure paper that is in the shadow area that occurs when light is shined on it, or paper that has a circular side edge and does not have a clear shadow.

〔Example〕

A first embodiment of the present invention will be described based on FIG.

Linearly polarized laser light is generated from a He-Ne laser 6 (wavelength: 633 nm, output: 1 mw) as a light source, and is linearly polarized accurately in the horizontal direction by a polarizer Glan-thomson prism 7. Next, this laser light is applied to a polarizing beam splitter 8 to transmit only the horizontally polarized component. The phase of this transmitted light is rotated by 45° by a quarter-wave plate 9 made of mica or quartz, thereby turning it into circularly polarized light. The laser beam is focused by a convex lens 2 and irradiated onto the side surface of the paper 3 stacked vertically on a rectilinear table 11. By moving the rectilinear table 11 in a rectilinear manner by the drive mechanism 12, it becomes possible to scan the side surface of the paper placed on the table from end to end with a laser beam.

The light reflected from the side edges of the paper 3 is again focused by the lens 2 and applied to the quarter-wave plate 9.

As a result, the phase of the light is further rotated by 45 degrees, and the polarized light becomes vertically linearly polarized light. Then, when this light passes through the polarizing beam splitter 8, the vertically polarized component is bent at right angles. This light is then condensed by the convex lens 15 and focused on the photodetector 5. This photodetector 5 measures the brightness and darkness of the reflected light, thereby measuring the number of sheets of paper and the shape of the side edges of the paper.

In this embodiment, a quarter wavelength plate is used as the quarter wavelength correction component, but a Fresnel lobe or the like may also be used.

In addition, the polarizer 7 is used to accurately linearly polarize the laser beam horizontally, but when using a laser beam with good linear polarization characteristics generated by a semiconductor laser, etc., the polarizer 7 is used.
can also be omitted.

A portion of the results of measuring stacked business cards using this method are shown in FIG. In this figure, the vertical axis shows the output (V) of the photodetector, and the horizontal axis shows the distance along the side edges of the stacked papers. According to this, the gap between business cards and 0.15r++
The thickness of one business card m can be observed very clearly, and as a result, the number of business cards can be accurately counted. Furthermore, as shown for the first to fifth sheets of paper counting from the left, the shape of the side of each business card is also clearly shown. On the other hand, it can be seen that the 6.7th and 8th sheets of paper counting from the left have an abnormal arrangement of the sheets as shown in FIG. FIG. 9 shows the results of re-measurement after the abnormal arrangement of the papers was rearranged to normal. In this case, the shapes of the first to eighth sheets of paper are accurately shown, and the number of sheets of paper is also accurately counted.

FIG. 4 shows the measurement results of copy sheets folded in four and stacked in a similar manner. In this figure as well, the units of the vertical and horizontal axes are the same as in FIG. 3. In this case, even though the side edges of the papers are on a circle, the gaps between the papers and the shape of each sheet of paper are clearly shown.

Moreover, its resolution has reached 1 μm.

Next, a second embodiment of the present invention will be described based on FIG.

In this embodiment, the polarizer 7 in the first embodiment,
The polarizing beam splitter 8 and the quarter wave plate 9 are replaced by a holographic plate 13. Further H
The e-Ne laser 6 is replaced with a semiconductor laser 16,
The photodetector 5 is placed at a position I mm away from the semiconductor laser 16 and is mounted integrally with the semiconductor laser 16.

Since these components in the first embodiment are replaced by a single holographic plate, the counting device in this second embodiment is extremely compact.

In the counting device of the first and third embodiments described above, the linear table on which nine pieces of paper were placed was moved in order to change the relative position between the incident laser beam and the side edge of the paper. The laser light source may be moved.

It is also possible to improve the S/C ratio of measurement by transmitting laser light through a filter and using only a single wavelength for measurement.

Furthermore, the measurement accuracy can be further improved by using an autofocusing element to constantly irradiate the side of the paper with a spot size of 1 μm to automatically correct the focus shift.

〔Effect of the invention〕

The paper measuring device of the present invention has the following effects.

(1) As can be seen from the measurement results of the first example (Figures 3 and 4), the shape of the paper side edge can be detected accurately, so it is possible to detect defective products that do not have a regular edge cross-sectional shape. , an abnormal state in which the sheets are not lined up correctly as shown in FIGS. 7 and 8 can be easily detected.

At this time, it is also possible to warn of this abnormal state by an alarm or the like so that the operator can correctly rearrange the sheets in the abnormal arrangement and count the number of sheets again.

In addition, the thickness of each sheet of paper can be accurately measured.

Furthermore, even if the cross section of the side edge of the paper is circular or bent, this condition is reliably detected, so the number of sheets of paper can be counted accurately without making a mistake. Furthermore, unlike conventional paper sheet counters that can only count paper thickness within an extremely narrow range or require different types of paper sheet counters for each thickness of paper, the present invention One paper measuring device can handle a wide range of thicknesses (0, 1,
It is possible to accurately count the number of sheets of paper of any thickness (as long as it is 1 mm or more).

(2) Since the relationship between linear polarization and circular polarization of laser light is utilized, measurement sensitivity and measurement resolution are significantly improved compared to conventional paper counting counters. Furthermore, if a solid-state laser is used as the laser light source, it is possible to downsize the paper measuring device.

(3) Measurement is performed with the axis of the incident light irradiated from the laser light source on the side of the paper and the reflected light from it kept the same, so there is no mechanism for making the light incident obliquely and changing the angle of incidence. This becomes unnecessary and the structure of the paper measuring device becomes simpler.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the invention. FIG. 2 shows a second embodiment of the invention. 3 and 4 show the measurement results of the first example. FIG. 5 shows a conventional paper counter. FIG. 6 is a diagram illustrating the principle of measuring the number of paper sheets using a conventional paper counter. FIGS. 7 and 8 are cross-sectional views of the side end surfaces of the bundled papers. FIG. 9 shows the results of paper measurement using the paper count meter of the present invention. 1-...Light bulb 2,14.15...Lens 3...Bundled paper 3a-31...Paper 4...
Frame 5...Photoelectric conversion element 6...He-
Ne laser 7... Polarizer 8... Polarizing beam splitter 9... Quarter wavelength plate 10... Digital counter 11... Straight table 12... Feeding mechanism 13... Holographic plate 16... Semiconductor laser patent applicant Dipol Co., Ltd. Figure 2 Figure 3 Figure 4 Figure Figure Figure Figure Figure Figure Figure

Claims (10)

[Claims] (1) A light source that generates a laser beam, a polarizing beam splitter, a quarter wavelength correction component, a convex lens, and a photodetector; The light source, the polarizing beam splitter, irradiating the side edge of the stacked papers with the laser beam that has passed through the correction component and the convex lens, and aligning the axes of the incident light and the reflected light at the side edge. one fourth of the said
a wavelength correction component and the convex lens are arranged, the polarization beam splitter is arranged so that the reflected light is reflected in a direction perpendicular to the axis, and the light reflected by the polarization beam splitter is detected by the light detection. A paper measuring device, characterized in that the photodetector is arranged so that the light is incident on a container, and a mechanism is provided for relatively moving the incident light and a side edge of the paper. (2) The paper measuring device according to claim (1), further comprising a polarizer. (3) The paper measuring device according to claim (1) or (2), wherein the reflected light reflected by the polarizing beam splitter is focused on the photodetector by a convex lens. (4) Claim (1), characterized in that only the selected single wavelength light is transmitted through the filter and incident on the side surface of the paper;
The paper measuring device described in (2), (3) or (4). (5) The paper measuring device according to any one of the preceding claims, characterized by comprising an autofocusing element. (6) The paper measuring device according to any one of the preceding claims, wherein the laser light source is a semiconductor laser. (7) It has a light source that generates a laser beam, a holographic plate, a convex lens, and a photodetector, and the side edges of the stacked papers are irradiated with the laser beam that has passed through the light source, the holographic plate, and the convex lens. , a mechanism configured such that the light reflected by the paper passes through the holographic plate and reaches the photodetector, and changes the relative position of the side edge of the paper and the laser beam incident on the side edge. A paper measuring device characterized by being provided with. (8) The paper measuring device according to claim (7), characterized in that a filter is used to use only a single wavelength light. (9) The paper measuring device according to claim (7) or (8), further comprising an autofocusing element. (10) The paper measuring device according to claim (7), (8) or (9), wherein the laser light source is a semiconductor laser.