JP2006335559A - Sheet material identifying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet material identifying device capable of accurately identifying a sheet material. <P>SOLUTION: A kind of sheet material 200 is identified on the basis of an electric signal output from a detecting part 300 by a shock by applying the shock to the sheet material 200 by a shock impressing member 100. The detecting part 300 can accurately identify the sheet material 200 by reducing influence of noise by making a natural oscillation frequency mutually different in the thickness direction, the length direction and the width direction of the detecting part 300. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet material identification device, and more particularly to an apparatus for identifying a type of a sheet material by applying an impact to the sheet material.

  Conventional image forming apparatuses such as copiers, printers, and fax machines, in addition to ordinary copy paper, form images on sheet materials such as glossy paper, coated paper, and film-like transparent resin. .

  In such an image forming apparatus that forms an image on various types of sheet materials, a sheet for identifying the type of the sheet material in order to perform an optimal image forming process depending on the type of the sheet material. There is a material identification device, and after identifying the type of the sheet material by the sheet material identification device, an image is formed under conditions such as a conveyance speed and a fixing temperature according to the sheet material.

  Here, as such a sheet material identification device, an impact application member having an impact application unit that applies an impact to the sheet material from the outside and a detection unit that includes a piezoelectric element that outputs an electric signal by the impact is provided. Is detected by the output signal obtained from the piezoelectric element, and the type of the sheet material is identified based on this detection. The thing is proposed (for example, refer patent document 1).

Japanese Patent Laid-Open No. 2004-026486

  However, in such a conventional sheet material identification device, when receiving the impact force of the impact application member, the detection unit receives a compression force and a shear force, and accordingly, an output signal corresponding to the compression force and the shear force from the piezoelectric element. Will occur.

  When such an output signal is generated, the output signal becomes noise, and this noise is superimposed on an output voltage waveform used for a desired sheet material type as shown in FIG. And in order to identify a sheet | seat material with high precision, reducing the influence by such a noise component is calculated | required.

  Therefore, the present invention has been made in view of such a current situation, and an object of the present invention is to provide a sheet material identification device capable of accurately identifying a sheet material.

  The present invention includes a sheet material identification device that includes an impact applying member that applies an impact to a sheet material, and a detection unit that outputs an electrical signal by the impact, and identifies the type of the sheet material based on the electrical signal from the detection unit The detection unit is characterized in that the vibration frequencies inherent in the thickness direction, the length direction, and the width direction of the detection unit are different from each other.

  According to the present invention, the detection unit that outputs an electric signal for identifying the type of the sheet material by the impact applied to the sheet material is different from each other in the inherent vibration frequency in the thickness direction, the length direction, and the width direction of the detection unit. By doing so, the influence of noise can be reduced, and the sheet material can be identified with high accuracy.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a sheet material identification device according to the present embodiment. In FIG. 1, 100 is an impact applying member, 200 is a sheet material, and 300 is a detection unit. The detection unit 300 includes a piezoelectric element 301 for converting an impact force (mechanical energy) into electric energy, and electrodes 304 and 305 for extracting output signals from the piezoelectric element 301.

  Here, the detection unit 300 includes protective members 302 and 303 for preventing the piezoelectric element 301 from being destroyed by the impact force of the impact applying member 100. The piezoelectric element 301 is protected by sandwiching the element 301. The impact applying member 100 is generally made of a solid substance (metal, plastic, alloy, etc.), and the protective members 302 and 303 are generally made of a metal having high rigidity.

  In such a sheet material identification device, when the type of the sheet material 200 is identified, the impact applying member 100 is made to collide with the sheet material 200. Here, when the impact applying member 100 collides with the sheet material 200 in this way, a part of the impact energy is absorbed by the sheet material 200 and the remaining impact energy that is not absorbed by the sheet material 200 is added to the detection unit 300. It is done.

  The remaining impact energy is first converted from mechanical energy to electrical energy by the piezoelectric element 301 in the detection unit 300 and output from the piezoelectric element 301 as an electrical signal. Further, this electrical signal is then sent to, for example, a sheet material identification unit (not shown), and in this sheet material identification unit, it is compared with data corresponding to the type of sheet material 200 stored in advance. The type of the sheet material 200 is identified.

  FIG. 2 shows how the detecting unit 300 vibrates when the impact applying member 100 collides with the sheet material 200 and the remaining impact energy absorbed by the sheet material 200 due to the collision is applied to the detecting unit 300. In this case, the natural vibration frequency of the detection unit 300 is substantially determined by the material, thickness, length, and width of the piezoelectric element 301 and the protection members 302 and 303.

  On the other hand, when the impact force of the impact applying member 100 is received from above as indicated by an arrow C, the detection unit 300 is compressed by the impact force and receives the compression force A shown in FIG. An electric signal corresponding to is generated between the electrodes 304 and 305.

  When receiving the impact force, the detection unit 300 generates bending vibration and shear force B at the same time, and an electric signal corresponding to the shear force B is transmitted from the piezoelectric element 301 between the electrodes 304 and 305. Occurs. That is, when receiving an impact force by the impact application member 100, the detection unit 300 receives the compression force A and the shearing force B, and accordingly, the piezoelectric element 301 generates an electric power corresponding to the compression force A and the shearing force B. A signal is generated between the electrodes 304 and 305 simultaneously.

  Here, when an impact is applied to the sheet material 200 by the impact applying member 100, the natural vibration due to the mechanical properties of the sheet material 200 (for example, rigidity, Young's modulus, density, weight, basis weight, etc. of the sheet material 200). Since the frequency is low, an electric signal having a relatively low frequency is output. However, since the size and shape of the detection unit 300 are much smaller than those of the sheet material 200, the natural vibration frequency is high.

  For example, in the present embodiment, the natural vibration frequency of the sheet material 200 is about 1 KHz to 1.2 KHz, whereas the piezoelectric element 301 is 5 mm × 25 mm, and the protective members 302 and 303 are 5 mm × When using a 5 mm detector, the natural vibration frequency of the detection unit 300 is about 10 KHz.

  When electrical signals corresponding to the compression force A and the shearing force B are simultaneously generated from the piezoelectric element 301 in this way, the output signal from the detection unit 300 is an electrical signal having a relatively low frequency due to the mechanical characteristics of the sheet material 200. An output signal having a relatively high frequency due to the compression force A and the shearing force B generated by the inherent vibration of the detection unit 300 is superimposed on the signal.

  FIG. 6 described above shows a relatively high frequency generated by the inherent vibration of the detection unit 300 caused by the compressive force A and the shear force B in the electrical signal having a relatively low frequency due to the mechanical characteristics of the sheet material 200 as described above. This shows an example in which the output signal is superimposed.

  Here, as described above, an output signal based on the mechanical characteristics of the sheet material 200, that is, a desired output signal for identifying the sheet material 200, an output signal generated by vibration inherent to the detection unit 300, that is, noise. The superposition of the components greatly deteriorates the identification accuracy of the sheet material 200 when the output material is processed and the sheet material 200 is identified.

  When the thickness, length, or width of the detection unit 300 is different, each vibration (resonance) frequency is different depending on the thickness, length, and width. Depending on the length and width, the inherent vibration (resonance) frequency may be the same. When the inherent vibration (resonance) frequencies of the thickness, length, and width of the detection unit 300 become the same as described above, the vibration increases due to the resonance (resonance) action, and the compression force A and the shearing force are increased. The output signal from B is superimposed and output as a noise component with a larger value.

  Here, in order to separate the output signal based on the mechanical characteristics of the sheet material 200, that is, the desired output signal, and the output signal generated by the inherent vibration of the detection unit 300, that is, the noise component, desired band limitation is performed. However, when such a filter is provided, the apparatus becomes complicated and the cost is increased.

  Therefore, in the present embodiment, in order to reduce that the output signals due to the compression force A and the shear force B are superimposed and output as noise components without providing a filter, each of the thickness, length, and width of the detection unit 300 is reduced. The inherent vibration (resonance) frequency is made different.

  In this case, it is preferable that the inherent vibration (resonance) frequency of each of the thickness, length, and width of the detection unit 300 does not have an integer multiple harmonic relationship. Furthermore, it is preferable that the ratio of the intrinsic vibration (resonance) frequency of each of the thickness, length, and width of the detection unit 300 is 1: 1 + dielectric loss (tan δ) of the piezoelectric element.

  Here, since the inherent vibration of the detection unit 300 is substantially determined by the material, thickness, length, and width of the piezoelectric element 301 and the protection members 302 and 303, the thickness, length, In order to make the inherent vibration (resonance) frequency of each width different from each other, for example, the material of the piezoelectric element 301 and the protection members 302 and 303 is determined, and then the piezoelectric element 301 and the protection members 302 and 303 are determined. It is sufficient to optimize the dimensions.

  Note that an elastic body may be added to the detection unit 300 in order to control the inherent vibration (resonance) frequency of each of the thickness, length, and width of the detection unit 300. FIG. 3 is a diagram illustrating an example in which an elastic body is added to the detection unit 300 in this manner. In FIG. 3, 306 is an elastic body added to the piezoelectric element 301, and 307 is added to the protection member 303. It is an elastic body.

  As described above, the vibration (resonance) frequency inherent in each of the thickness, length, and width of the detection unit 300 is a different frequency, is out of the harmonic relationship of an integral multiple, and the ratio is 1: 1 + dielectric of the piezoelectric element. In order to optimize the mechanical dimension so as to be greater than the loss (tan δ), or to control the inherent vibration (resonance) frequency, the elastic member 306, 307 is added to the detection unit 300, whereby the sheet It is possible to reduce the superposition of the output signal generated by the inherent vibration of the detection unit 300, that is, the noise component, on the output signal based on the mechanical characteristics of the material 200, that is, the desired output signal.

  That is, as in the present embodiment, the influence of noise can be reduced by making the detection unit 300 have different vibration frequencies in the thickness direction, the length direction, and the width direction of the detection unit 300. The sheet material 200 can be identified with high accuracy.

  FIG. 4 is a diagram illustrating an example of a waveform of an output voltage obtained by optimizing the inherent vibration (resonance) frequency of each of the thickness, length, and width of the detection unit 300. As is clear from FIG. 4, by optimizing the inherent vibration (resonance) frequency of each of the thickness, length, and width of the detection unit 300, a desired band limitation for separately separating noise components can be obtained. The noise component due to the compressive force A and the shear force B can be reduced without providing the performed filter.

  By reducing the noise component in this way, only the difference depending on the type of the sheet material 200 can be obtained as the output voltage / output waveform, and the signal from the detection unit 300 is processed based on the result. The type of the sheet material 200 can be accurately identified. This makes it possible to form an optimum image in an image forming apparatus such as a copying machine, a printer, or a FAX.

  In the above description, the detection unit 300 is provided at a position facing the impact applying member 100 with the sheet material 200 interposed therebetween. However, the present invention is not limited to this, and as shown in FIG. The part 300 may be provided on the elastically deformable member 400 integrated with the impact applying member 100. In FIG. 5, reference numeral 500 denotes a fixed base. The fixed base 500 regulates the downward movement of the sheet material 200 when an impact is applied by the impact applying member 100.

  In such a sheet material identification device, when the impact applying member 100 is caused to collide with the sheet material 200 when identifying the type of the sheet material 200, a part of the impact energy is absorbed by the sheet material 200, and the sheet The remaining impact energy that is not absorbed by the material 200 is transmitted to the elastically deformable member 400 via the impact applying member 100. As a result, the detection unit 300 provided on the elastically deformable member 400 vibrates integrally with the elastically deformable member 400, and thus when the detection unit 300 vibrates integrally with the elastically deformable member 400 due to the remaining impact energy. An electrical signal is output from the piezoelectric element 301.

  In the description so far, the configuration in which the detection unit 300 is installed horizontally has been described as an example. However, the detection unit 300 is installed vertically, and an impact is applied to the sheet material 200 by the impact application member 100 from the horizontal direction. May be.

The figure which shows schematic structure of the sheet | seat material identification device which concerns on this Embodiment. The figure which shows the mode of the vibration of the detection part in the said sheet | seat material identification device. The figure which shows the example which added the elastic body to the said detection part. The figure which shows an example of the waveform of the output voltage obtained by optimizing the intrinsic | native vibration (resonance) frequency of each thickness, length, and width of the said detection part. The figure which shows the structure which integrated the said detection part with the impact application part. The figure which shows the output waveform of the piezoelectric element in the conventional sheet | seat material identification device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Impact application member 200 Sheet material 300 Detection part 301 Piezoelectric element 302 Protection member 303 Protection member 304 Electrode 305 Electrode 306 Elastic body 307 Elastic body 400 Elastically deformable member 500 Fixing base

Claims (8)

In a sheet material identification device that includes an impact applying member that applies an impact to a sheet material, and a detection unit that outputs an electrical signal by the impact, and identifies the type of the sheet material based on the electrical signal from the detection unit,
The sheet material identification device, wherein the detection unit has different vibration frequencies in the thickness direction, the length direction, and the width direction of the detection unit.   The sheet according to claim 1, wherein the detection unit is configured such that the vibration frequencies inherent in the thickness direction, the length direction, and the width direction of the detection unit are out of a harmonic relationship that is an integral multiple. Material identification device.   The detection unit includes a piezoelectric element that outputs an electric signal by the impact, and the ratio of the intrinsic vibration frequency in the thickness direction, the length direction, and the width direction of the detection unit is 1: 1 + dielectric loss (tan δ of the piezoelectric element). 2. The sheet material identification device according to claim 1, wherein the sheet material identification device is configured as described above.   The detection unit includes the piezoelectric element and a protection member for the piezoelectric element, and the thickness and length of the piezoelectric element and the protection member are different so that the vibration frequencies inherent in the thickness direction, the length direction, and the width direction of the detection unit are different. The sheet material identification device according to claim 1, wherein a width and a width are set.   The elastic body is added to the said detection part so that the intrinsic vibration frequency of the thickness direction of the said detection part, the length direction, and the width direction may mutually differ, The Claim 1 thru | or 3 characterized by the above-mentioned. Sheet material identification device.   The sheet material identification device according to claim 1, wherein the detection unit is provided at a position facing the impact applying member via the sheet material.   The sheet material identification apparatus according to claim 1, wherein the detection unit is provided integrally with the impact applying member. The sheet material identification device according to claim 7, wherein the detection unit is provided on an elastically deformable member provided in the impact applying member.

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