JP2005164303A - Water content measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water content measuring instrument capable of measuring the water content of an object to be measured with high precision. <P>SOLUTION: This water content measuring instrument is equipped with a reflecting plate 13 including a high reflectivity region 31 having relatively high reflectivity and a low reflectivity region 32 having relatively low reflectivity and reflecting the light transmitted through paper P. Since water content Q is operated based on the detection results of detectors 41 and 42 after light (reflected light R1H) including the light reflected by the high reflectivity region 31 of the reflecting plate 3 is detected by a detector 41 and light (reflected light R1L) including the light reflected in the low reflectivity region 32 by a detector 42, the operational precision of the water content Q is enhanced by the addition quantity of the effect of a light transmission phenomenon. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a moisture content measuring apparatus used for measuring the moisture content of an object to be measured such as paper.

  In recent years, a moisture content measuring apparatus has been used to measure the moisture content of an object to be measured such as paper. As this moisture content measuring device, for example, the intensity of reflected light generated when light is irradiated to the object to be measured is detected, and the intensity of the reflected light changes according to the moisture content of the object to be measured. A device that calculates the water content of the object to be measured is known.

Specifically, for example, light from a light source to an object to be measured has two types of wavelength ranges, that is, light having a high water absorption property of 1 μm or more and light having a low water absorption property of less than 1 μm. , And the intensity of the reflected light is detected using two types of detection means having detection sensitivity in each wavelength region, so that the intensity of light in the two wavelength regions included in the reflected light is between There is known a water content measuring device that calculates the water content based on the relationship (see, for example, Patent Document 1). This water content measuring device does not require a mechanism (a turret type selector having a plurality of optical filters) for wavelength-separating light emitted from a light source.
JP 2000-283916 A

Further, for example, light of three types from the light source to the object to be measured, that is, light of one infrared absorption wavelength (light having a high water absorption property) and light of two infrared comparison wavelengths (light of infrared absorption wavelength) The intensity of the reflected light generated when the light is irradiated with light having a low water absorption property corresponding to the shorter wavelength side or the longer wavelength side), and the light of the three wavelengths included in the reflected light is detected. A moisture content measuring device that calculates a moisture content by correcting an error (error caused by factors other than light absorption by water) based on the relationship between the strengths is known (for example, see Patent Document 2). . Specifically, in this moisture content measuring device, after calculating the scattering rate of light of infrared absorption wavelength by extrapolating the reflectance of light of infrared comparison wavelength, the scattering rate and reflection of light of infrared absorption wavelength are calculated. By calculating the absorption rate based on the rate, the moisture content of the object to be measured is specified based on the absorption rate. In this moisture content measuring apparatus, errors due to disturbance (surface roughness of the object to be measured) are corrected.
Japanese Patent Laid-Open No. 03-115838

As described above, as a moisture content measuring device, in addition to the device that calculates the moisture content based only on the detection result of the reflected light, for example, when the transmittance of the object to be measured cannot be ignored, A device that calculates the water content based on the detection result of the transmitted light together with the detection result is also known. As this type of moisture content measuring device, for example, light of two types from the light source to the object to be measured, that is, light in a wavelength region with high water absorption and light in a wavelength region with low water absorption. After irradiating, the intensity of the transmitted light that has been transmitted once through the object to be measured (one time transmitted light) and the intensity of the reflected light that has been reflected once at the object to be measured (one time reflected light) are detected. There is one that calculates the water content based on the relationship between the intensity of the once transmitted light and the once reflected light (for example, see Patent Document 3). In this moisture content measuring device, the ideal measurement state of the multiple scattering method is reproduced.
Japanese Patent Publication No. 05-045137

  By the way, in order to measure the moisture content of the object to be measured with high accuracy using the moisture content measuring device, it is necessary to remove the factors that may cause an error in the moisture content measurement accuracy and to make the error as small as possible. is there. In this regard, the above-described conventional moisture content measuring device is useful, but it can be said that there is still room for improvement with respect to the measurement accuracy of the moisture content measuring device, considering the need for further improvement in measurement accuracy. In this regard, some of the conventional moisture content measuring devices detect the intensity of the transmitted light as well as the intensity of the reflected light, and calculate the moisture content in consideration of the effect of the light transmission phenomenon on the object to be measured. However, in order to reduce the error and improve the water content measurement accuracy, it is necessary to detect the influence of the light transmission phenomenon as accurately as possible.

  The present invention has been made in view of such problems, and an object thereof is to provide a moisture content measuring apparatus capable of measuring the moisture content of an object to be measured with high accuracy.

  The moisture content measuring apparatus according to the present invention includes a light source that emits irradiation light toward an object to be measured, a high reflectance region having a relatively high reflectance, and a low reflectance region having a relatively low reflectance. A reflection plate that reflects light transmitted through the object to be measured, and light reflected by the object to be measured without passing through the reflector and light reflected by the reflection plate after passing through the object to be measured The reflected light intensity detecting means for detecting the intensity of the reflected light including the light and the calculating means for calculating the water content of the object to be measured based on at least the detection result of the reflected light intensity detecting means.

  In the moisture content measuring apparatus according to the present invention, in a reflector including a high reflectance region having a relatively high reflectance and a low reflectance region having a relatively low reflectance, light transmitted through the object to be measured Since the light is reflected, the reflected light intensity detecting means detects the intensity of the reflected light including both the light reflected in the high reflectance region and the light reflected in the low reflectance region of the reflector. Thereby, based on the detection result of the reflected light intensity detecting means, the calculating means can calculate the water content of the object to be measured in consideration of the influence of the light transmission phenomenon.

  In the moisture content measuring apparatus according to the present embodiment, the reflecting plate reflects light in the high reflectance region and simultaneously reflects light in the low reflectance region, so that the reflected light intensity detecting means reflects in the high reflectance region. The reflected light and the light reflected in the low reflectance region may be detected in parallel, or the light is reflected in the low reflectance region separately from the reflection plate reflecting the light in the high reflectance region. Thus, the reflected light intensity detecting means may separately detect the light reflected in the high reflectance region and the light reflected in the low reflectance region.

  The water content measuring apparatus according to the present invention further includes an optical filter that separates the reflected light guided to the reflected light intensity detecting means into light in a wavelength range of a predetermined wavelength or more and light in a wavelength range of less than a predetermined wavelength. The reflected light intensity detecting means separately detects light in a wavelength region of a predetermined wavelength or more and light in a wavelength region of less than a predetermined wavelength separated by the optical filter, and the calculating means in the reflected light intensity detecting means The water content may be calculated based on the detected intensity of light in the wavelength range equal to or greater than the predetermined wavelength and the intensity of light in the wavelength range less than the predetermined wavelength. In this case, the optical filter is preferably made of germanium when the predetermined wavelength is 1.8 μm, and the optical filter is preferably made of silicon when the predetermined wavelength is 1.0 μm. .

  Further, the moisture content measuring apparatus according to the present invention may further include a reflection / scattering means for guiding the irradiation light irradiated from the light source to the object to be measured by reflecting and scattering the irradiation light. In this case, the reflection / scattering means is preferably an integrating sphere.

  The water content measuring apparatus according to the present invention further includes irradiation light intensity detection means for detecting the intensity of irradiation light emitted from the light source, and the calculation means includes the detection result of the reflected light intensity detection means and the irradiation light intensity detection means. The water content may be calculated based on the detection result. In this case, the irradiated light intensity detecting means is different from the reflected light intensity detecting means, and the irradiated light may be directly detected, or the reflected light intensity detecting means is used as the irradiated light intensity detecting means. It also serves as a function, and the irradiation light may be indirectly detected through a reflector.

  The expression “separating reflected light into light having a wavelength range of a predetermined wavelength or more and light having a wavelength range of less than a predetermined wavelength” relating to the above “optical filter” is, for example, a predetermined wavelength of 1.8 μm. Is not limited to the case where light having a wavelength of 1.8 μm or more is strictly separated from light having a wavelength of 1.8 μm or more and light having a wavelength of less than 1.8 μm using the wavelength of 1.8 μm as a reference (boundary). The ratio of light in the wavelength range of 1.8 μm or more is large (light that includes most of light in the wavelength range of 1.8 μm or more and slightly includes light in the wavelength range of less than 1.8 μm) and 1 in the whole In some cases, the light occupies a large proportion of light in the wavelength region of less than 8 μm (light that includes most of light in the wavelength region of less than 1.8 μm and slightly includes light in the wavelength region of less than 1.8 μm). Including meaning. The meaning of this expression means that “the intensity of light in the wavelength region of 1.8 μm or more and the intensity of light in the wavelength region of less than 1.8 μm are separately detected” regarding “reflected light intensity detection means”, “ The same applies to the expression “calculating the water content based on the intensity of light in the wavelength region of 1.8 μm or more and the intensity of light in the wavelength region of less than 1.8 μm” regarding the “calculation means”. Of course, the matters described above regarding the case where the predetermined wavelength is 1.8 μm are the same as those when the predetermined wavelength is 1.0 μm.

  According to the moisture content measuring apparatus of the present invention, the light relating to the object to be measured based on the intensity of the reflected light including both the light reflected in the high reflectance region and the light reflected in the low reflectance region of the reflector. Since the water content is calculated in consideration of the effect of the light transmission phenomenon, the calculation accuracy of the water content is improved by the amount that takes into account the effect of the light transmission phenomenon. Therefore, the moisture content of the measurement object having permeability can be measured with high accuracy.

  In addition to the above, the water content measuring apparatus according to the present invention includes an optical filter that separates the reflected light into light in a wavelength range of a predetermined wavelength or more and light in a wavelength range of less than a predetermined wavelength, and the computing means If the water content is calculated based on the intensity of light in a wavelength range equal to or greater than the predetermined wavelength and the intensity of light in a wavelength range less than the predetermined wavelength, for example, the predetermined wavelength based on the water absorbability of light. By taking into account the difference between the intensity of light in the wavelength range above the predetermined wavelength with high water absorption and the intensity of light in the wavelength range below the predetermined wavelength with low water absorption Since the water content is calculated, the calculation accuracy of the water content is improved. Therefore, the water content can be measured with extremely high accuracy.

  Further, in the moisture content measuring apparatus according to the present invention, if reflection / scattering means for guiding the irradiation light emitted from the light source to the object to be measured is reflected and scattered, the angle distribution of the intensity of the reflected light is improved. Factors that can cause an error in the measurement accuracy of the moisture content from the viewpoint are removed, and the error is reduced. Therefore, this aspect can also contribute to high-accuracy measurement of water content.

  The water content measuring apparatus according to the present invention further includes irradiation light intensity detection means for detecting the intensity of irradiation light emitted from the light source, and the calculation means includes the detection result of the reflected light intensity detection means and the irradiation light intensity detection means. If the water content is calculated based on the detection result, for example, the water content is calculated in consideration of the intensity change of the irradiation light caused by deterioration of the light source or the like. Therefore, since the reflectance of the object to be measured is calculated in consideration of the intensity of the reflected light as well as the intensity of the reflected light, it is possible to contribute to high-accuracy measurement of water content from this viewpoint.

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

[First Embodiment]
First, with reference to FIG. 1 and FIG. 2, the structure of the moisture content measuring apparatus which concerns on the 1st Embodiment of this invention is demonstrated. 1 and 2 show a cross-sectional configuration of the moisture content measuring apparatus according to the present embodiment. FIG. 1 shows an irradiation state of irradiation light, and FIG. 2 shows a detection state of reflected light.

  This water content measuring device is mounted on, for example, a copying machine or a printer, and is used to measure the water content Q of the paper P as the object to be measured, and is mainly permeable (for example, thin or low). Density) is used for measuring the water content Q of the paper P. For example, as shown in FIGS. 1 and 2, the moisture content measuring apparatus reflects a light source 1 that irradiates light (irradiation light I) toward the paper P and the irradiation light I emitted from the light source 1. This is based on the integrating sphere 2 (reflection scattering means) that leads to the paper P by being scattered, the reflecting plate 3 that reflects a part of the irradiation light I that has passed through the paper P, and the irradiation light I. Detectors 4 and 5 (reflected light intensity detecting means) for detecting the intensity of the reflected light R, wavelength limiting filters 6 and 7, a condensing lens 8 and a wavelength separating filter 9 (optical filter) And. The integrating sphere 2 is provided with openings 2KA, 2KB and 2KC, for example, on the side, below and above, respectively, and a baffle 21 as a barrier is provided inside the integrating sphere 2.

  The light source 1 emits infrared light as irradiation light I, for example, infrared light including light having a wavelength range of 1.8 μm or more. The light source 1 is constituted by, for example, a filament light bulb, and is disposed in the opening 2KA of the integrating sphere 2.

  The integrating sphere 2 is a substantially spherical vessel for guiding the irradiation light I isotropically to the paper P by confining and reflecting and scattering the irradiation light I emitted from the light source 1 to the paper P. The integrating sphere 2 has, for example, an uneven structure (for example, a surface roughness of about several tens of μm) on the inner surface (scattering surface 2M) in order to improve the reflection / scattering property of the irradiation light I. Has a configuration in which a high-infrared reflective scattering film 2S constituting the scattering surface 2M is provided on the inner surface of a metal sphere 2G. The scattering film 2S is, for example, a metal plating film (for example, gold, silver, copper, chromium, nickel, or the like), or a coating film (for example, fluorine resin, polyethylene, or the like) that has fine depressions or cavities (bubbles) for light scattering. Inorganic pigments, etc.), metal oxide vapor deposition films (for example, magnesium oxide), and metal oxide films (for example, anodized) in which the inner surface of the sphere 2G (for example, aluminum) is anodized. In the case where the scattering film 2S is made of a metal other than gold, for example, a gold plating film for anticorrosion may be further provided on the surface of the scattering film 2S.

  As described above, the reflecting plate 3 reflects a part of the irradiation light I transmitted through the paper P toward the detectors 4 and 5. This reflector 3 is located in two regions arranged in parallel, that is, on one side and has a relatively high reflectance region 31 and on the other side, and has a relatively low reflectance. For example, both the high reflectivity region 31 and the low reflectivity region 32 are arranged corresponding to the opening 2KB of the integrating sphere 2, and the high reflectivity region 31 is formed. The light is reflected at the low reflectance region 32 at the same time. Note that “relatively high reflectance” means that when the reflectance of the high reflectance region 31 and the reflectance of the low reflectance region 32 are compared, the reflectance of the high reflectance region 31 is low. This means that the reflectance of the low reflectance region 32 is lower than the reflectance of the light reflectance region 31. Yes. The high reflectivity region 31 is constituted by, for example, a film formed by applying a solution containing barium sulfate and a binder, that is, a coating film in which barium sulfate is dispersed in the binder. For example, a film formed by applying a solution containing graphite and a binder, that is, a coating film in which graphite is dispersed in the binder.

  The detectors 4 and 5 have detection sensitivity in the infrared wavelength region, and both detect the intensity of the reflected light R. Among these, the detector 4 detects light (reflected light R1) including light in the wavelength region of 1.8 μm or more in the reflected light R, and is a main for measuring the moisture content Q of the paper P. This is a means for detecting the reflected light R. The detector 4 includes two detectors 41 arranged in parallel, that is, a detector 41 that detects light (reflected light R1H) that includes light reflected by the high reflectivity region 31 of the reflecting plate 3 out of the reflected light R1, and a low detector 41. And a detector 42 that detects light (reflected light R1L) including light reflected in the reflectance region 32. For example, light reflected in the high reflectance region 31 and light reflected in the low reflectance region 32 Are detected in parallel. On the other hand, the detector 5 detects light (reflected light R2) including light in a wavelength region of less than 1.8 μm in the reflected light R, and is an auxiliary for measuring the water content Q of the paper P. This is a means for detecting the reflected light R. The detector 5 includes a detector 51 that detects light (reflected light R2H) that includes light reflected by the high reflectivity region 31 of the reflecting plate 3 out of the two detectors arranged in parallel, that is, the reflected light R2, and a low detector 51. And a detector 52 that detects light (reflected light R2L) including light reflected in the reflectance region 32. For example, as in the detector 4 (41, 42), the light is reflected in the high reflectance region 31. The light and the light reflected in the low reflectance region 32 are detected in parallel. The detectors 41 and 42 and the detectors 51 and 52 are respectively arranged corresponding to the two light guiding directions based on the wavelength separation action of the filter 9. The detectors 41 and 42 are composed of, for example, an indium gallium arsenide alloy photodiode or a thermoelectromotive force element. The detectors 51 and 52 are constituted by, for example, a silicon photodiode, a germanium photodiode, an indium gallium arsenide alloy photodiode, or a thermoelectromotive force type element. If necessary, the detectors 51 and 52 may be used in combination with a wavelength limiting spectroscopic unit such as a thin film interference filter, a band pass filter, or a diffraction grating.

  The filters 6 and 7 limit the wavelength range of infrared rays (reflected light R1 and R2) that can pass (transmit) to the detectors 4 and 5, respectively. Among these, the filter 6 transmits light including light in the wavelength region of 1.8 μm or more of the reflected light R1, for example, germanium mainly having infrared absorption characteristics in a wavelength region of less than 1.8 μm. (For example, a germanium plate). This filter 6 is composed of two filters 61 and 62 arranged in parallel corresponding to the detectors 41 and 42. On the other hand, the filter 7 transmits light including light in a wavelength region of less than 1.8 μm of the reflected light R2, for example, has an infrared absorption characteristic mainly in a wavelength region of less than 1.0 μm, It is made of silicon (for example, a silicon plate) having infrared transmission characteristics in a wavelength region within a range of 1.0 μm or more and less than 1.8 μm. This filter 7 is composed of two filters 71 and 72 arranged in parallel corresponding to the detectors 51 and 52.

  The lens 8 collects the reflected light R and guides it to the filter 9 and is made of, for example, glass. This lens 8 is designed so that the detection viewing angles of the detectors 4 and 5 are included in the exposed region of the paper P (the region exposed corresponding to the opening 2KB when viewed from the inside of the integrating sphere 2). Yes.

  The filter 9 functions as a half mirror that separates the wavelength of the reflected light R, and is arranged along with the lens 8 so as to correspond to the opening 2KC of the integrating sphere 2. Specifically, the filter 9 transmits the light (reflected light R1) including light in the wavelength region of 1.8 μm or more out of the reflected light R and guides it to the detector 4, and the wavelength region of less than 1.8 μm. The light including the light (reflected light R2) is reflected and guided to the detector 5, and is made of, for example, germanium (eg, a germanium plate). In addition, the expression “transmitting light in the wavelength region of 1.8 μm or more of the reflected light R” described above transmits strictly light in the wavelength region of 1.8 μm or more (wavelength of less than 1.8 μm). Not only in the case of not transmitting any light in the region, but also transmitting light with a large proportion of light in the wavelength region of 1.8 μm or more in the whole (mostly transmitting light in the wavelength region of 1.8 μm or more) , And slightly transmits light in the wavelength region of less than 1.8 μm).

  The reason why only the reflected light R1 is transmitted through the filter 9 toward the detector 4 which is a detection means for the main reflected light R is as follows. In other words, generally, there are three known wavelength ranges of infrared light having a high water absorption property, ie, around 1.4 μm, around 1.9 μm, and around 3.0 μm. If infrared light is used, it is possible to measure the water content Q of the paper P based on the intensity change of the infrared light accompanying the absorption phenomenon by water. In particular, when measuring the moisture content Q of a paper P (for example, printed matter) having a small water absorption as the object to be measured, for example, a wavelength in the vicinity of 1.9 μm or 3.0 μm of infrared light in three wavelength ranges. It is preferred to use a range of infrared light. This is because the infrared light in the wavelength region near 1.4 μm has lower water absorption than the infrared light in the other two wavelength regions, so the detector 4 detects a change in the intensity of the infrared light due to water absorption. It is difficult. Furthermore, when infrared light having a wavelength region near 1.4 μm is used, the light source 1 and the detector 4 having excellent monochromaticity are required, which is not preferable for reducing the cost of the water content measuring device.

  Note that the filter 9 is replaced with, for example, a germanium plate, and other filter materials having infrared absorption characteristics mainly in a wavelength region of less than 1.8 μm, specifically a diffraction grating, a thin film interference filter, like the germanium plate. Or you may be comprised by the band pass filter etc. However, these other filter materials are generally expensive and, in particular, when a diffraction grating with insufficient light utilization efficiency is used, the high-power type light source 1 and the high-sensitivity detectors 4 and 5 are required. Since this increases the cost of the apparatus, it is preferable to use an inexpensive germanium plate in order to reduce the cost of the apparatus. If this germanium plate is used as the filter 9, it is possible to stably transmit the reflected light R1 by utilizing the infrared absorption characteristics based on the interband transition of the germanium element.

  The baffle 21 prevents the irradiation light I from being directly irradiated onto the paper P without being reflected and scattered by the integrating sphere 2 and reflects the irradiation light I toward the paper P. It arrange | positions in the position between 2 opening part 2KA, 2KB. Whether or not the baffle 21 is provided can be freely set.

  Note that the paper P as the object to be measured is supported by a transport mechanism (not shown) such as a transport roller mounted together with a moisture content measuring device in, for example, a copying machine or a printer, and passes above the reflector 3. Then, it is conveyed sequentially.

  Next, with reference to FIGS. 1-3, the detailed structure of a moisture content measuring apparatus is demonstrated. FIG. 3 shows a block configuration of the water content measuring device shown in FIGS. 1 and 2.

  This water content measuring device includes a memory 10 for storing various information together with a series of components including the light source 1 and the detectors 4 (41, 42), 5 (51, 52) shown in FIGS. A controller 11 (arithmetic means) for controlling the entire apparatus, an amplifier 12 for amplifying the output signals of the detectors 4 and 5, and an analog / digital (A / D) converter for converting the output signal from an analog signal to a digital signal 13. In FIG. 3, in order to simplify the illustration, the combination of the amplifier 12 and the A / D converter 13 is shown together. However, the combination of the amplifier 12 and the A / D converter 13 is the detector 41, 42. , 51 and 52 are mounted in plural sets.

  The memory 10 stores information necessary for the controller 11 to calculate the water content Q. For example, a register, a RAM (Random Access Memories), a ROM (Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read). Storage device such as Only Memory). In the memory 10, for example, calculation data including calibration curve data C representing a correlation between an absorptivity / scattering rate ratio AD / SD described later and a water content Q is stored in advance as a constant.

  The controller 11 reads out necessary calculation data from the memory 10 at any time and calculates the water content Q based on the detection results of the detectors 4 and 5, for example, a CPU (Central Processing Unit). Control device.

  For example, the controller 11 detects a detector as necessary in order to prevent an error in the calculation result of the water content Q due to unnecessary infrared light (background radiation) generated from a heat source other than the light source 1. 4 has a function of correcting the detected intensity. Specifically, the controller 11 detects, for example, the detection result of the detector 4 when the light source 1 is operating and the irradiation light I is irradiated, and the light source 1 is stopped and irradiated at predetermined calculation intervals. By comparing the detection result of the detector 4 when the light I is not irradiated, the difference between these two detection results (the intensity of the mixed light in which the reflected light R1 and the light caused by background radiation are mixed) And the difference between the intensity of light caused by background radiation) and the calculated value is used as the reflected light R generated on the paper P when the irradiation light I is irradiated from the light source 1 to the detector 4. As a result of detection (that is, the intensity of the reflected light R1), the moisture content Q is corrected based on the calculated value.

  Next, with reference to FIGS. 1-3, operation | movement of a moisture content measuring apparatus is demonstrated. In the following, first, the optical principle that is established in the water content measuring device will be described, and then the operation of measuring the water content Q by the controller 11 will be described.

  In this moisture content measuring device, the following optical principle is established between the light source 1 and the detectors 4 (41, 42), 5 (51, 52). That is, as shown in FIG. 1, in a state where the paper P is conveyed to a position corresponding to the opening 2KB of the integrating sphere 2, when the irradiation light I is irradiated from the light source 1, the irradiation light I is converted into the integrating sphere. By being reflected and scattered on the second scattering surface 2M, the light is guided to the paper P through the opening 2KB, and is irradiated to the paper P isotropically. This “isotropic” means that the intensity of the irradiation light I is substantially proportional to the cosine of the angle between the axis (perpendicular) perpendicular to the paper P and the irradiation direction of the irradiation light I. .

  When the irradiation light I is irradiated onto the paper P, as shown in FIG. 2, reflected light R is generated at the paper P and in the vicinity thereof. That is, the reflected light R is a light generated when a part of the irradiation light I is reflected on the paper P without passing through the reflection plate 3, and the rest of the irradiation light is transmitted through the paper P. Thereafter, the light is mixed with the light generated by being reflected by the reflector 3 (the high reflectance region 31 and the low reflectance region 32). The “light generated by being reflected on the paper P” includes not only light reflected on the surface of the paper P but also light reflected inside the paper P (without passing through the paper P). It is out. The “light generated by being reflected by the reflecting plate 3” is not only the light that is reflected by the reflecting plate 3 and then immediately transmitted again through the paper P, but also after being reflected by the reflecting plate 3. It also includes light that has passed through the paper P again after being subjected to multiple reflections one or more times between P and the reflector 3.

  When the reflected light R is generated, only the component of the reflected light R that travels in the arrangement direction of the lens 8 and the filter 9 is guided to the lens 8 through the opening 2KC of the integrating sphere 2 and is condensed at the lens 8. By being guided to the filter 9 later, the wavelength is separated in the filter 9 functioning as a half mirror. That is, the light (reflected light R1) including light in the wavelength range of 1.8 μm or more having high water absorbability in the reflected light R is selectively transmitted through the filter 9 and further wavelength-limited in the filter 6. This leads to the detector 4. At this time, among the reflected light R1, the light (reflected light R1H) including light including light reflected by the high reflectance region 31 of the reflector 3 is detected by the detector 41 after passing through the filter 61, and Light (reflected light R <b> 1 </ b> L) including light reflected in the low reflectance region 32 is detected by the detector 42 after passing through the filter 62. On the other hand, the remainder of the reflected light R, that is, the light (reflected light R2) containing light in the wavelength range of less than 1.8 μm, which is low in water absorption, is reflected by the filter 9 and further wavelength-limited by the filter 7. Is led to the detector 5. At this time, among the reflected light R2, light (reflected light R2H) including light reflected by the high reflectivity region 31 of the reflector 3 is detected by the detector 51 after passing through the filter 71, and also has a low reflectivity. Light (reflected light R <b> 2 </ b> L) including light reflected in the region 32 is detected by the detector 52 after passing through the filter 72.

  In the state where the optical principle described above is established, the controller 11 calculates the water content Q of the paper P based on the detection result of the detector 4 (41, 42) by the following procedure. That is, first, the reflectance RD is calculated based on the intensity of the known irradiation light I and the intensity of the reflected light R1 (R1H, R1L) detected by the detector 4 (41, 42). Subsequently, an absorptance / scattering ratio AD / SD is calculated based on the reflectance RD. Finally, the calibration curve data C is read from the memory 10, and the moisture content Q corresponding to the absorption rate / scattering rate ratio AD / SD is specified based on the calibration curve data C. Thereby, the water content Q is calculated based on the detection result of the detector 4 (41, 42).

The calculation principle of the absorptance / scattering ratio AD / SD by the controller 11 is as follows. That is, for example, when the transmittance of the paper P is so small that it can be ignored, the relational expression of the following equation 1 is established between the reflectance RD, the absorption factor AD, and the scattering factor SD based on the Kubelka-Munk scattering model. The relationship between the absorption rate AD and the scattering rate SD is expressed as a function of the reflectance RD. Here, in general, assuming that the reflectivity when the material of the paper P is constant and the thickness is infinite is R∞, the following relational expression 2 is established. Further, when the reflectance of the reflecting plate 3 is RG and the basis weight of the paper P is W (g / m ² ), the following relational expression 3 is established for the reflectance RD. Furthermore, the reflectance of the high reflectance region 31 of the reflector 3 is RG1, the reflectance of the low reflectance region 32 is RG2, and the light including the light reflected in the high reflectance region 31 of the reflected light R ( When the reflectance of the reflected light R1H) is R1, and the reflectance of the light including the light reflected in the low reflectance region 32 (reflected light R1L) is R2, the following relational expression 4 is established with respect to the reflectance R∞. To do. Therefore, if the reflectance R∞ is calculated by using the relational expression of Equation 4 by measuring the reflectances R1 and R2 after setting the reflectances RG1 and RG2 to be constant (known), the reflectance R Based on ∞, it is possible to calculate the ratio between the absorption rate AD and the scattering rate SD, that is, the absorption rate / scattering rate ratio AD / SD, using the relational expression of Formula 2.

  In particular, the controller 11 calculates the water content Q based on the calibration curve data C from the detection result of the detector 4 (41, 42) and the detection result of the detector 5 (51, 52) in the process of calculating the water content Q. To do.

  The calculation principle of the water content Q by the controller 11 is as follows. That is, the relational expression 1 based on the above Kubelka-Munk scattering model applies the relational expression 4 for light including light in the wavelength range of 1.8 μm or more (reflected light R1 = R1H, R1L). By calculating the reflectivity R1∞, f (R1∞) = AD1 / SD1. On the other hand, with respect to light including light in the wavelength region of less than 1.8 μm (reflected light R2 = R2H, R2L), Assume that f (R2∞) = AD2 / SD2 is calculated by calculating the reflectance R2∞ after applying the relational expression. These R2∞, AD2 and SD2 correspond to the reflectance, absorption rate and scattering rate of the paper P itself (excluding water), respectively. Therefore, if the calibration curve data C is set as a correspondence relationship between the two reflectances R1∞ and R2∞ and the moisture content Q, the moisture content Q of the paper P is calculated based on the calibration curve data C. It becomes possible. In this case, based on the difference between the intensity of the reflected light R1 having a high water absorbency and the intensity of the reflected light R2 having a low water absorbency, the parameters specific to the paper P as the object to be measured are previously set. By setting the scattering rate ratio SD1 / SD2, it becomes possible to calculate the water content Q without the influence of fluctuations in the scattering rate SD1, so the calculation accuracy of the water content Q is improved. For example, depending on the spectral sensitivity characteristics of the detector 5, light having a wavelength range of 1.8 μm or more can also be detected by the detector 5. In this case, based on the detection results of the detectors 4 and 5, the detector 5. By calculating the contribution of the intensity of light in the wavelength region of 1.8 μm or more with respect to the detection value, the detection value of the detector 5 is corrected based on the calculation result.

  In the moisture content measuring apparatus according to the present embodiment, the light that has passed through the paper P includes the high reflectance region 31 having a relatively high reflectance and the low reflectance region 32 having a relatively low reflectance. Since the reflecting plate 3 to be reflected is provided, the detector 41 detects light (reflected light R1H) including light reflected in the high reflectance region 31 of the reflecting plate 3 and the detector 42 in the low reflectance region 32. It is possible to calculate the water content Q based on the detection results of the detectors 41 and 42 by detecting the light including the reflected light (reflected light R1L) and using the above-described relational expressions 2 and 4. Become. In this case, when the transmittance of the paper P is so large that it cannot be ignored, the light transmission phenomenon is compared with the case where the water content Q is calculated without taking into consideration the influence of the light transmission phenomenon on the paper P. The calculation accuracy of the water content Q is improved by an amount that takes into account the effect of. Therefore, in the present embodiment, the water content Q of the permeable paper P can be measured with high accuracy.

  In particular, in the present embodiment, based on the point that the measurement accuracy of the moisture content Q of the paper P is improved, printing is performed according to the moisture content Q of the paper P in a copier or printer equipped with the moisture content measuring device. By controlling the conditions, the print quality can be improved.

  Further, in the present embodiment, the following relational expression 5 is established with respect to the basis weight W of the paper P by modifying the relational expression of Expression 3. Therefore, if the controller 11 calculates the basis weight W of the paper P using the relational expression of Formula 5 as necessary, the basis weight W can be calculated in addition to the water content Q of the paper P. it can.

  Further, in this embodiment, the reflected light R is wavelength-separated, that is, light (reflected light R1) including light having a wavelength range of 1.8 μm or more with high water absorption and low water absorption 1.8. A filter 9 is provided that separates light (reflected light R2) including light in a wavelength region less than that, and the reflected light R1 is detected by the detector 4 (41, 42) and the reflected light R2 is detected by the detector 5 (51, 52). Therefore, the controller 11 can calculate the water content Q in consideration of not only the detection result of the detector 4 (41, 42) but also the detection result of the detector 5 (51, 52). In this case, as described above, based on the difference between the intensity of the reflected light R1 having a high water absorption property and the intensity of the reflected light R2 having a low water absorption property, the calibration curve data C is used for the paper. The moisture content Q of P can be measured with extremely high accuracy.

  Further, in the present embodiment, the integrating sphere 2 that leads to the paper P by reflecting and scattering the irradiation light I emitted from the light source 1 is provided, so that it is reflected and scattered on the scattering surface 2M of the integrating sphere 2. Irradiation light I is irradiated isotropically onto the paper P. In this case, unlike the case where the integrating sphere 2 is not provided and the irradiation light I is not irradiated isotropically on the paper P, the intensity of the reflected light R has an angular distribution based on a substantially complete scattering surface, that is, the paper. Since the intensity of the reflected light R is substantially proportional to the cosine of the angle between the axis perpendicular to P and the traveling direction of the reflected light R, the absolute reflectance can be calculated as the reflectance RD of the paper P. become. Therefore, in the present embodiment, the error due to the angular distribution of the intensity of the reflected light R is reduced, and this aspect can also contribute to high-precision measurement of the water content Q. In this case, in particular, since the irradiation light I irradiated from the light source 1 is confined in the integrating sphere 2, the irradiation efficiency of the irradiation light I irradiated onto the paper P is improved. A sufficient output can be secured.

  In the present embodiment, since the lens 8 made of glass is used, the reflected light R is obtained by utilizing the infrared absorption characteristic of glass, that is, the characteristic of absorbing infrared light in a wavelength region of 4.0 μm or more. Passes through the lens 8, infrared light having a wavelength region of 4.0 μm or more of the reflected light R is absorbed by the lens 8. Therefore, since the reflected light R excluding light in an unnecessary wavelength range that induces a measurement error due to thermal radiation is guided to the filter 9, the calculation result of the moisture content Q is caused by the presence of this unnecessary infrared light. Including errors can be prevented.

  Further, in the present embodiment, on the basis of the wavelength separation action of the filter 9 and the infrared absorption characteristic of the lens 8, light (reflection) in a wavelength range within a relatively narrow range substantially 1.8 μm or more and less than 4.0 μm. Since the water content Q is calculated using the light R1), the infrared light in the two types of wavelength regions described in the above “Background Art” section (light having a water absorption property of 1 μm or more and light The measurement accuracy of the water content Q is further improved as compared with a conventional water content measuring device using a light having a wavelength of less than 1 μm, which is low in water absorption. This is because, in the conventional case using light in a relatively wide wavelength range of 1 μm or more, the entire wavelength range is too large relative to the wavelength range of light absorbed by water. The reflected light energy in the wavelength range that is water-absorbing with respect to the light energy becomes extremely small, and it is difficult to detect the change in the reflected light intensity, whereas it is a relatively narrow range between 1.8 μm and less than 4.0 μm. In the case of the present embodiment using light in the wavelength range, the reflected light energy in the water-absorbing wavelength range is larger than the reflected light energy in the entire wavelength range compared to the conventional case. This is because it becomes easy to detect the change in the reflected light intensity.

  In the present embodiment, the light source 1 that irradiates the irradiation light I including infrared light having a wavelength range of 1.8 μm or more is used, but is not necessarily limited thereto. You may make it use what irradiates only the infrared rays of the wavelength range more than 1.8 micrometers as the irradiation light I. Examples of this type of light source 1 include an LED (Light Emitting Diode) and an LD (Laser Diode) that can irradiate only infrared light in a wavelength region near 1.9 μm. Even in this case, the same effect as the above embodiment can be obtained.

  In the present embodiment, in addition to the wavelength separation filter 9, the wavelength limiting filters 6 (61, 62) and 7 (71, 72) are further provided. However, the present invention is not limited to this. Instead, for example, the wavelength separation action of the filter 9 is sufficient, and the filter 6 (61, 62), 7 (71, 72) is used in addition to the filter 9 to change the wavelength of the reflected light R to the secondary. If it is not necessary to limit to the above, the filters 6 (61, 62) and 7 (71, 72) may not be provided.

  In the present embodiment, as described above, when the light source 1 that irradiates only the infrared light having a wavelength range of 1.8 μm or more as the irradiation light I is used, for example, separately from the light source 1, You may make it use the other light source which irradiates only the infrared light of the wavelength range below 1.8 micrometers as the irradiation light I. FIG. Examples of the “other light source” include an LD (Laser Diode) that can selectively irradiate only infrared light having a wavelength range of less than 1.8 μm. In this case, the same effect can be obtained.

  Further, in the present embodiment, as shown in FIG. 2, the reflector 3 is arranged so that both the high reflectance region 31 and the low reflectance region 32 are located corresponding to the opening 2KB of the integrating sphere 2. In other words, light is reflected in the high reflectivity region 31 and light is reflected in the low reflectivity region 32 at the same time, so that the detectors 4 and 5 include light reflected by the high reflectivity region 31 (reflected light R1H, R2H). ) And light including the light reflected by the low reflectance region 32 (reflected light R1L, R2L) are detected in parallel. However, the present invention is not necessarily limited to this. , R1L, R2H, R2L, and the configuration of the reflector 3 is not limited as long as the controller 11 can calculate the water content Q of the paper P based on the detection results of the detectors 4 and 5. It can be changed to. Specifically, for example, as shown in FIGS. 4 to 7, after arranging the reflector 3 so that the high reflectance region 31 is positioned corresponding to the opening 2KB of the integrating sphere 2 in the initial state, The reflector 3 is moved so that the low reflectance region 32 is positioned corresponding to the opening 2KB of the integrating sphere 2, that is, the low reflectance region 32 is separated from the light reflected by the high reflectance region 31. The light (R1H, R2H) including the light reflected by the detectors 4 and 5 in the high reflectivity region 31 and the light (R1L, R2L) including the light reflected in the low reflectivity region 32 are reflected by reflecting the light in FIG. You may make it detect separately.

  4 and 5, for example, a rotatable shaft 33 is provided between the high reflectance region 31 and the low reflectance region 32, and the reflector 3 can be rotated about the rotational shaft 33. It has become. In this case, for example, as shown in FIG. 4, the reflector 3 is arranged so that the high reflectivity region 31 is positioned corresponding to the opening 2KB of the integrating sphere 2 in the initial state, and the detector 4 (41 , 42) and the detector 5 (51, 52) detects the reflected light R2H, and then the low reflectivity region 32 corresponds to the opening 2KB of the integrating sphere 2 as shown in FIG. By rotating the reflector 3 so as to be positioned, the detector 4 (41, 42) can detect the reflected light R1L and the detector 5 (51, 52) can detect the reflected light R2L.

  On the other hand, in FIG. 6 and FIG. 7, for example, the reflecting plate 3 is provided with a slide mechanism (not shown), and the reflecting plate 3 can be slid in the direction of the arrow Y1 using this slide mechanism. Also in this case, for example, as shown in FIG. 6, the reflector 3 is arranged so that the high reflectivity region 31 is positioned corresponding to the opening 2KB of the integrating sphere 2 in the initial state, and the detector 4 (41 , 42) and the detector 5 (51, 52) detects the reflected light R2H, and then the low reflectivity region 32 corresponds to the opening 2KB of the integrating sphere 2 as shown in FIG. By sliding the reflecting plate 3 so as to be positioned, the detector 4 (41, 42) can detect the reflected light R1L and the detector 5 (51, 52) can detect the reflected light R2L.

  In any of the cases shown in FIG. 4 and FIG. 5 or FIG. 6 and FIG. 7, the controller 11 can calculate the water content Q of the paper P based on the detection results of the detectors 4 and 5. The same effect can be obtained. 4 to 7, the position of the reflector 3 corresponding to the opening 2KB of the integrating sphere 2 is shifted from the high reflectance region 31 to the low reflectance region 32. However, the present invention is not limited to this, and the low reflectance region 32 may be shifted to the high reflectance region 31. In addition, the structure except the above regarding the water content measuring apparatus shown in FIGS. 4-7 is the same as that of the case shown in FIG.

  Further, in the present embodiment, as shown in FIG. 2, only one moisture content measuring mechanism including the light source 1, integrating sphere 2, detectors 4, 5, filters 6, 7, 9 and lens 8 is provided. However, the present invention is not necessarily limited to this. For example, as shown in FIG. 8, the two moisture content measuring mechanisms having the same configuration correspond to the high reflectance region 31 in the reflector 3. The water content measuring unit 100A arranged in the manner described above and the water content measuring unit 100B arranged corresponding to the low reflectance region 32 may be provided. In this case, the reflected lights R1H and R2H are detected by the detectors 4 and 5 of the water content measuring unit 100A, and at the same time, the reflected lights R1L and R2L are detected by the detectors 4 and 5 of the water content measuring unit 100B. The controller 11 measures the moisture content of the paper P based on the detection results of both the moisture content measuring units 100A and 100B. Even in this case, since the controller 11 can calculate the water content Q of the paper P based on the detection results of the water content measuring units 100A and 100B (detectors 4 and 5), the same effect as the above embodiment can be obtained. Can do. In addition, the structure except the above regarding the moisture content measuring apparatus shown in FIG. 8 is the same as that of the case shown in FIG.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

  9 and 10 show a cross-sectional configuration of the moisture content measuring apparatus according to the present embodiment, FIG. 9 shows an irradiation state of irradiation light, and FIG. 10 shows a detection state of irradiation light. In FIGS. 9 and 10, the same components as those described in the first embodiment are denoted by the same reference numerals.

  The moisture content measuring apparatus according to the present embodiment differs from the first embodiment in which the moisture content Q is calculated based only on the detection result of the reflected light R, and the irradiation light together with the detection result of the reflected light R. The water content Q is calculated based on the detection result of I. Specifically, for example, as shown in FIG. 9 and FIG. 10, the moisture content measuring device is configured to supply a light source in a state where the paper P is transported from the reflection plate 3, that is, the paper P is not present on the reflection plate 3. 1 except that the reflected light R0 (the irradiated light I reflected by the reflector 3) can be detected by the detectors 4 and 5 by irradiating the irradiated light I from 1. It has the same configuration as the moisture content measuring apparatus (see FIGS. 1 to 3) of the embodiment.

  As described in the first embodiment, the reflecting plate 3 reflects the reflected light R including the light transmitted through the paper P toward the detectors 4 and 5 in the state where the paper P exists, In the state where the paper P does not exist, the irradiation light I is reflected as the reflected light R0 toward the detectors 4 and 5.

  The detectors 4 and 5 also have a function of detecting the intensity of the reflected light R0 (that is, the intensity of the irradiated light I) as well as a function of detecting the intensity of the reflected light R (irradiated light intensity detecting means). Thus, the intensity of the irradiation light I is indirectly detected. Here, “indirect” means that the irradiation light I emitted from the light source 1 is not detected without being reflected by the reflecting plate 3 but is detected after being reflected by the reflecting plate 3. .

  In this moisture content measuring apparatus, when the irradiation light I is irradiated from the light source 1 in a state where the paper P is conveyed on the reflection plate 3, as shown in FIG. 1 and FIG. Based on the optical principle described in the embodiment, the reflected light R is generated when the irradiation light I reflected and scattered on the scattering surface 2M of the integrating sphere 2 is isotropically irradiated onto the paper P. At this time, using the wavelength separation action of the filter 9, the light (reflected light R 1) including light in the wavelength region of 1.8 μm or more of the reflected light R is guided to the detector 4 and is less than 1.8 μm. Light (reflected light R <b> 2) including light in the wavelength band is guided to the detector 5. Thereby, the light (reflected light R1H) including the light reflected in the high reflectance region 31 of the reflecting plate 3 among the reflected light R1 is detected by the detector 41 and includes the light reflected in the low reflectance region 32. Light (reflected light R1L) is detected by the detector 42. Of the reflected light R2, light including the light reflected by the high reflectivity region 31 of the reflector 3 (reflected light R2H) is detected by the detector 51, and the light includes light reflected by the low reflectivity region 32. (Reflected light R2L) is detected by the detector 52.

  On the other hand, when the irradiation light I is irradiated from the light source 1 in a state where the paper P is conveyed from the reflection plate 3, as shown in FIGS. 9 and 10, the reflection plate 3 is irradiated isotropically. Since the irradiation light I is reflected as reflected light R0 on the reflector 3 and then guided to the filter 9 via the lens 8, the wavelength separation action of the filter 9 is used as in the case of the reflected light R described above. Then, light (reflected light R01) including light in the wavelength region of 1.8 μm or more of the reflected light R0 is guided to the detector 4 and light including light in the wavelength region of less than 1.8 μm (reflected light R02). ) Is led to the detector 5. Thereby, the light (reflected light R01H) including the light reflected in the high reflectance region 31 of the reflecting plate 3 among the reflected light R01 is detected by the detector 41 and includes the light reflected in the low reflectance region 32. (Reflected light R01L) is detected by the detector 42. Of the reflected light R02, light including the light reflected by the high reflectance region 31 of the reflector 3 (reflected light R02H) is detected by the detector 51 and includes light reflected by the low reflectance region 32. (Reflected light R02L) is detected by the detector 52.

  In this case, the controller 11 shown in FIG. 3 calculates the water content Q based on the detection results of the detectors 4 and 5 by the following operation procedure. That is, first, the reflectance RD is calculated based on the intensity of the reflected light R (R1H, R1L, R2H, R2L) and R0 (R01H, R01L, R02H, R02L) detected by the detectors 4 and 5. Subsequently, the absorptance / scattering ratios AD1 / SD1 and AD2 / SD2 are calculated based on the reflectance RD. Finally, the calibration curve data C is read from the memory 10, and the moisture content Q corresponding to the absorptance / scattering ratios AD1 / SD1 and AD2 / SD2 is specified based on the calibration curve data C. Thereby, the water content Q is calculated based on the detection results of the detectors 4 and 5.

  The detection process of the reflected light R0 by the detector 4 and the calculation process of the moisture content Q based on the intensity of the reflected lights R and R0 are performed every time the moisture content Q is measured, for example. Alternatively, it may be performed every predetermined measurement interval (for example, every 10 measurements). In the latter case, the intensity of the reflected light R and the intensity of the previously detected reflected light R0 (or an arithmetic expression reflecting the deterioration state of the light source 1 are used to calculate the intensity based on the reflected light R0. The water content Q is calculated based on (strength).

  In the moisture content measuring apparatus according to the present embodiment, the reflector 3 reflects the irradiation light I as the reflected light R0 toward the detectors 4 and 5, so that the detectors 4 and 5 reflect the reflected light R0 together with the intensity of the reflected light R. The detectors 4 and 5 can detect the intensities of the reflected lights R and R0, and calculate the water content Q based on the detection results of the reflected lights R and R0. become. In this case, unlike the first embodiment in which the water content Q is calculated using the intensity of the irradiation light I as an invariant constant, the intensity of the irradiation light I is caused by, for example, deterioration of the light source 1. When the intensity changes with time, the intensity of irradiation light I after the change with time is measured, and the intensity of reflected light R and the intensity change of irradiation light I (intensity change of reflected light R0) are taken into account. Q is calculated. Therefore, in the present embodiment, a factor that may cause an error in the measurement accuracy of the moisture content Q in terms of intensity change of the irradiation light I is removed, and the error is eliminated, so that the moisture content Q of the paper P is increased. It can be measured with high accuracy.

  In the present embodiment, detectors 4 (41, 42) and 5 (51, 52) have a function of detecting the intensity of reflected light R and a function of detecting the intensity of reflected light R0 (that is, the intensity of irradiation light I). In other words, the detectors 4 and 5 indirectly detect the intensity of the irradiation light I through the reflector 3, but the present invention is not limited to this. For example, as shown in FIG. Detectors 4 (43) and 5 (53) for detecting the intensity of the irradiation light I are provided separately from the detectors 4 (41, 42) and 5 (51, 52) for detecting the intensity of the reflected light R. These detectors 43 and 53 may directly detect the intensity of the irradiation light I. The moisture content measuring apparatus shown in FIG. 11 does not have a mechanism for irradiating the irradiation light I from the light source 1 in the state where the paper P is present on the reflection plate 3, for example, and opens to the side of the integrating sphere 2. A portion 2KD is provided, and an irradiation light intensity detection lens 81, a filter 91, and detectors 43 and 53 (irradiation light intensity detection means) are arranged corresponding to the opening 2KD, and an opening is formed in the integrating sphere 2. Other integration spheres 22 are connected through 2KA, and the configuration similar to that of the water content measurement device of the above-described embodiment except that the light source 1 is disposed in the integration sphere 22 (see FIGS. 9 and 10). )have.

  The integrating sphere 22 leads the integrating sphere 2 through the opening 2KA by reflecting and scattering the irradiation light I, and has, for example, the same configuration as the integrating sphere 2, that is, the scattering surface on the inner surface of the sphere 22G. The scattering film 22S constituting 22M is provided. The dimension (for example, inner diameter) of this integrating sphere 22 is smaller than the dimension of the integrating sphere 2, for example. Inside the integrating sphere 22, a baffle 23 is disposed at a position between the light source 1 and the opening 2KA. The lens 81 condenses the irradiation light I and has, for example, the same configuration as the lens 8. Whether or not the lens 81 is provided can be freely set. The filter 91 separates the wavelength of the irradiation light I and has the same configuration as the filter 9, for example. The filter 91 transmits light (irradiation light I1) including light in the wavelength range of 1.8 μm or more out of the irradiation light I to the detector 43 and includes light in a wavelength range of less than 1.8 μm. The light (irradiation light I2) is reflected and guided to the detector 53. The detectors 43 and 53 detect the intensity of the irradiation light I, and directly detect the intensity of the irradiation light I emitted from the light source 1 as described above. The detectors 43 and 53 have the same configuration as the detectors 4 and 5, for example. The term “directly” as used herein is different from the above-described embodiment in which the irradiation light I emitted from the light source 1 is reflected on the reflecting plate 3 and then detected as the reflected light R0. This means that light other than the reflected light R0 is detected (irradiation light I is detected as it is). The detector 43 detects the intensity of light (irradiation light I1) including light in the wavelength region of 1.8 μm or more in the irradiation light I, and the detector 53 detects light in the wavelength region of less than 1.8 μm. The intensity of the included light (irradiation light I2) is detected.

  In the moisture content measuring apparatus shown in FIG. 11, when the reflected light R is generated by irradiating the irradiation light I from the light source 1 with the paper P being conveyed, the wavelength separation of the filter 9 is performed as in the above embodiment. After the reflected light R is separated into the reflected lights R1, R2 by using the action, the reflected lights R1H, R1L, R2H, R2L are detected by the detectors 41, 42, 51, 52, respectively. At this time, the irradiation light I emitted from the light source 1 is guided to the filter 91 via the lens 81 through the opening 2KD, and thus the wavelength separation action of the filter 91 is used in the same manner as the reflected light R described above. Since the irradiation light I is separated into the irradiation lights I1 and I2, the detectors 43 and 53 detect the irradiation lights I1 and I2, respectively. Thereby, the intensity of the reflected light R (R1H, R1L, R2H, R2L) detected by the detectors 41, 42, 51, 52 and the intensity of the irradiation light I (I1, I2) detected by the detectors 43, 53 Based on the calculation procedure similar to the above embodiment, the controller 11 shown in FIG.

  In the moisture content measuring apparatus shown in FIG. 11, in addition to the detectors 41, 42, 51, 52 for detecting the intensity of the reflected light R, the detectors 43, 53 for detecting the intensity of the irradiation light I are provided. The detectors 41, 42, 51, 52 detect the intensity of the reflected light R, and the detectors 43, 53 detect the intensity of the irradiated light I. The detected results of the reflected light R and the detected result of the irradiated light I are included. It becomes possible to calculate the water quantity Q. Therefore, the water content Q of the paper P can be measured with higher accuracy by the same operation as the above embodiment.

  In this case, in particular, by arranging the light source 1 in the integrating sphere 22 connected to the integrating sphere 2, the light source 1 is arranged in the integrating sphere 2 without connecting the integrating sphere 22 to the integrating sphere 2. Unlike the case where it is provided, since most of the irradiation light I is reflected and scattered by the integrating spheres 2 and 22 and then enters the detectors 43 and 53, the error due to the angular distribution of the intensity of the irradiation light I is reduced. . Further, the irradiation light I is wavelength-separated by using the filter 91, that is, the light (irradiation light I1) including light having a wavelength range of 1.8 μm or more with high water absorption and low water absorption 1.8. By detecting the intensity of the irradiation light I based on the light including the light in the wavelength range of less than (irradiation light I2), the detection accuracy of the intensity of the irradiation light I can be detected in the same manner as when the reflected light R is wavelength-separated. improves. Therefore, the moisture content of the paper P can be measured with extremely high accuracy based on the suppression of errors caused by the angular distribution of the intensity of the irradiation light I and the improvement in detection accuracy of the intensity of the irradiation light I.

  In addition, the detailed actions, operations, effects, and the like other than those described above regarding the water content measurement device according to the present embodiment are the same as those in the first embodiment.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and can be freely modified as long as the same effect as the embodiment can be obtained. It is. Specifically, for example, in the above-described embodiment, the case where the moisture content of the paper is measured using the moisture content measuring device of the present invention has been described. If a water amount measuring device is used, it is also possible to measure the water content of objects to be measured other than paper. Examples of the “other object to be measured” include cloth, soil, dough such as bread or noodle, food such as seaweed or tea, and the like. Even in this case, the same effect as the above embodiment can be obtained.

  In particular, in the above-described embodiment, when measuring the water content of paper as the object to be measured, in order to measure the water content of the paper, it is known as the wavelength region of infrared light having a high water absorption property 3 Infrared light in the wavelength range near 1.9 μm or near 3.0 μm is used in one wavelength range (near 1.4 μm, near 1.9 μm, near 3.0 μm), but is not limited to this. For example, when measuring the moisture content of a measured object other than paper, especially when the moisture content of a food (such as bread or noodle dough) that has a large variation in moisture content, the moisture content of the measured object It is possible to appropriately select the wavelength range of infrared light according to the above. Specifically, for example, when the water content is very large as an object to be measured, it is preferable to use infrared light in the wavelength region near 1.4 μm, while when the water content is very small, It is preferable to use infrared light in a wavelength region near 0 μm. By appropriately selecting the wavelength range of the infrared light according to the water content of the object to be measured, the water content of the object to be measured can be measured with high accuracy.

  When using infrared light in the wavelength region near 1.4 μm, in particular, in order to enable the detector 4 to detect the reflected light R1 including light in the wavelength region near 1.4 μm, the filter 9 is made of silicon (for example, The filter 9 selectively transmits light (reflected light R1) including light in the wavelength region of 1.0 μm or more out of the reflected light R and guides it to the detector 4 and less than 1.0 μm. It is preferable to selectively reflect light (reflected light R2) including light in the wavelength range to the detector 5. Also in this case, the reflected light R1 is detected by the detector 4 and the reflected light R2 is detected by the detector 5, and the controller 11 calculates the water content Q based on the detection result of the detector 5 together with the detection result of the detector 4. Therefore, the water content Q can be measured with extremely high accuracy as in the case of using infrared light in the wavelength region near 1.9 μm.

  In the above embodiment, the case where the moisture content of the permeable object to be measured is measured using the moisture content measuring device of the present invention is not limited to this. You may make it measure the water content of a non-permeable (for example, thick and high density) to-be-measured object using a water content measuring apparatus. Even in this case, the water content of the object to be measured can be measured with high accuracy.

  The water content measuring apparatus according to the present invention can be used for measuring the water content of an object to be measured such as paper.

It is sectional drawing showing the schematic structure of the irradiation state of the irradiation light of the moisture content measuring apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing showing schematic structure of the detection state of the reflected light of the water content measuring apparatus shown in FIG. It is a block diagram showing the block configuration of the moisture content measuring apparatus shown in FIG. 1 and FIG. It is sectional drawing showing the cross-sectional structure before rotation of the reflecting plate of the moisture content measuring apparatus as a 1st modification regarding the moisture content measuring apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing showing the cross-sectional structure after rotation of the reflecting plate of the moisture content measuring apparatus shown in FIG. It is sectional drawing showing the cross-sectional structure before the slide of the reflecting plate of the moisture content measuring apparatus as a 2nd modification regarding the moisture content measuring apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing showing the cross-sectional structure after the slide of the reflecting plate of the moisture content measuring apparatus shown in FIG. It is sectional drawing showing the cross-sectional structure of the moisture content measuring apparatus as a 3rd modification regarding the moisture content measuring apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing showing the cross-sectional structure of the irradiation state of the irradiation light of the moisture content measuring apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing showing the cross-sectional structure of the detection state of the irradiation light of the moisture content measuring apparatus shown in FIG. It is sectional drawing showing the cross-sectional structure of the moisture content measuring apparatus as a modification regarding the moisture content measuring apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light source, 2, 22 ... Integrating sphere, 2KA-2KC ... Opening, 2G, 22G ... Sphere, 2M, 22M ... Scattering surface, 2S, 22S ... Scattering film, 3 ... Reflecting plate, 4 (41, 42, 43 ), 5 (51, 52, 53) ... Detector, 6 (61, 62), 7 (71, 72), 9, 91 ... Filter, 8, 81 ... Lens, 10 ... Memory, 11 ... Controller, 12 ... Amplifier 13 ... A / D converter, 21, 23 ... baffle, 31 ... high reflectivity region, 32 ... low reflectivity region, 33 ... rotating shaft, 100A, 100B ... moisture content measuring unit, AD ... absorption rate, AD / SD: Absorbance / scattering ratio, AD1 / AD2: Absorption ratio, I (I1, I2): Irradiation light, P: Paper, R (R1, R1H, R1L, R2, R2H, R2L), R0 (R01, R01H, R01L, R02, R02H, R02L) ... reflected light RD ... reflectance, SD ... scattering rate, Q ... water content, W ... basis weight.

Claims (11)

A light source that emits irradiation light toward the object to be measured;
A reflector that includes a high reflectivity region having a relatively high reflectivity and a low reflectivity region having a relatively low reflectivity, and reflects light transmitted through the object to be measured;
Reflected light intensity detecting means for detecting the intensity of reflected light including both the light reflected by the object to be measured without passing through the reflector and the light reflected by the reflector after passing through the object to be measured. When,
A water content measuring device comprising: a calculating means for calculating a water content of the object to be measured based on at least a detection result of the reflected light intensity detecting means. The reflector reflects light in the high reflectivity region and reflects light in the low reflectivity region;
The moisture content measuring device according to claim 1, wherein the reflected light intensity detecting means detects in parallel the light reflected in the high reflectance region and the light reflected in the low reflectance region. The reflecting plate reflects light in the low reflectance region separately from reflecting light in the high reflectance region,
The moisture content measuring device according to claim 1, wherein the reflected light intensity detecting unit separately detects light reflected in the high reflectance region and light reflected in the low reflectance region. Furthermore, an optical filter that separates the reflected light guided to the reflected light intensity detecting means into light in a wavelength region of a predetermined wavelength or more and light in a wavelength region of less than the predetermined wavelength,
The reflected light intensity detecting unit separately detects light in a wavelength region of the predetermined wavelength or more and light in a wavelength region of less than the predetermined wavelength separated by the optical filter;
The calculating means calculates the water content based on the intensity of light in the wavelength region of the predetermined wavelength or more detected by the reflected light intensity detecting means and the intensity of light in the wavelength region of less than the predetermined wavelength. The water content measuring device according to any one of claims 1 to 3, wherein The moisture content measuring apparatus according to claim 4, wherein the predetermined wavelength is 1.8 m, and the optical filter is made of germanium. The moisture content measuring apparatus according to claim 4, wherein the predetermined wavelength is 1.0 m, and the optical filter is made of silicon. Furthermore, the reflection scattering means which guides to the said to-be-measured object by reflecting and scattering the irradiation light irradiated from the said light source was provided. The one of the Claims 1 thru | or 6 characterized by the above-mentioned. Water content measuring device. The moisture content measuring apparatus according to claim 7, wherein the reflection / scattering means is an integrating sphere. Furthermore, an irradiation light intensity detecting means for detecting the intensity of irradiation light emitted from the light source is provided,
The said calculating means calculates a moisture content based on the detection result of the said irradiation light intensity detection means with the detection result of the said reflected light intensity detection means. Any one of Claim 1 thru | or 8 characterized by the above-mentioned. The water content measuring device described. The moisture content measuring device according to claim 9, wherein the irradiation light intensity detection means is different from the reflected light intensity detection means and directly detects the irradiation light. The moisture content measurement according to claim 9, wherein the reflected light intensity detection unit also functions as the irradiation light intensity detection unit, and indirectly detects the irradiation light through the reflection plate. apparatus.

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