JP2006329676A - Method and apparatus for measuring content in sealed letter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for measuring a content in a sealed letter, which can precisely and simply determining the number, thickness, material and the like of content sheets without opening it, by assuring a measurement value and a reference value being unaffected by changes in a measurement environment. <P>SOLUTION: The apparatus comprises: three electrodes making up two spaces which are a measurement space and a reference space disposed at prescribed intervals; a measurement circuit for measuring physical values of the two spaces; and a determining means which calculates a ratio of respective physical values of the measurement space and the reference space measured by the measurement circuit and determines at least one of the number, thickness and material of the content sheets contained in the sealed letter. The three electrodes are arranged so as to be laminated or side by side, whereby the measurement space and the reference space are arranged close to each other, and both spaces are set in the same environment. Moreover, the measurement circuit performs as a signal processing circuit for a differential capacitive sensor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sealed content measurement method and a measurement apparatus capable of determining the number of content and the like with high accuracy without opening a sealed letter (non-destructive), for example.

Conventionally, as a measuring apparatus for measuring the thickness and weight of an object to be measured using electrostatic capacitance, for example, the one shown in FIG. 12 is known. This measuring apparatus interposes a device under test 103 between a main electrode 101 and a counter electrode 102 that are fixedly opposed to each other, and measures a capacitance C10 that is a physical quantity between the electrodes 101 and 102. The measured capacitance C10 is compared with a preset reference value to obtain the number of objects 103 to be measured. In addition, there exists patent document 1 as literature regarding this measuring apparatus, for example.
Japanese Patent Laid-Open No. 8-029112

  However, in such a measuring apparatus, the measured capacitance C10 is simply compared with a reference value stored in advance, and the number of objects to be measured 103 is determined according to the size of the capacitance C10. Therefore, when the capacitance between the electrodes 101 and 102 changes depending on the environment of the place of use such as temperature and humidity, the capacitance C10 measured in this changed state is set to a predetermined reference value. It is difficult to accurately measure the capacitance C10 of the measurement object 103 itself, and it is difficult to determine (measure) the number of the measurement objects 103 with high accuracy.

  The present invention has been made in view of such circumstances, and its purpose is to open the number, thickness, material, etc. of sealed contents by ensuring a reference value and a measurement value that are not affected by changes in the measurement environment. It is an object of the present invention to provide a measuring method and measuring apparatus for sealed contents that can be accurately and easily determined without the need to do so.

  In order to achieve such an object, in the measurement method according to claim 1 of the present invention, two gaps of a measurement gap and a reference gap are formed by three electrodes having a predetermined gap, and a predetermined number of sheets are formed in the measurement gap. The physical quantity is measured by inserting a sealed letter containing the contents, and the physical quantity of the reference gap is measured, and the number of the contents contained in the sealed letter is obtained by determining the ratio of the measured physical quantities. Determining at least one of the materials.

  In this case, as in the invention described in claim 2, it is preferable that the sealed letter is inserted into the measurement gap by passing from one end opening to the other end opening of the measurement gap. As in the third aspect of the invention, it is preferable that the physical quantity of the measurement gap is measured in a state where a reference object is inserted in the reference gap.

  According to a fourth aspect of the present invention, there is provided a measuring apparatus according to a fourth aspect of the present invention, wherein three electrodes that are arranged with a predetermined interval to form two gaps of a measurement gap and a reference gap, and a physical quantity of the two gaps are measured. Measuring circuit to be measured, and determination means for determining a ratio of each physical quantity of the measurement gap and the reference gap measured by the measurement circuit and determining at least one of the number, thickness and material of the contents contained in the sealed letter And.

  In this case, the three electrodes are stacked in the thickness direction or arranged side by side in the plane direction as in the invention described in claim 5 so that the measurement gap and the reference gap are close to each other. It is preferable that both gaps are set in the same environment. Moreover, it is preferable that the measurement circuit functions as a signal processing circuit of a differential capacitive sensor as in the invention described in claim 6.

  According to the measuring method of the first aspect of the present invention, two gaps, a measurement gap and a reference gap, are formed by three electrodes, and a sealed letter containing a predetermined number of contents is inserted into the measurement gap. In order to determine at least one of the number, thickness, or material of the contents contained in the sealed letter by measuring the physical quantity and measuring the physical quantity of the reference gap, and determining the ratio of both measured physical quantities. Regardless of environmental changes, the physical quantity of the sealed letter in the measurement gap and the physical quantity of the reference gap can be measured with high accuracy, and the number of contents can be accurately measured without opening the sealed letter. It is possible to easily measure the number of contents, etc., simply by inserting them into the measurement gap.

  Further, according to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the sealed letter passes through the measurement gap from one end opening toward the other opening. Therefore, the sealed letter can be continuously supplied into the measurement gap, and the number of contents can be measured efficiently.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, since the physical quantity of the measurement gap is measured in a state where the reference object is inserted in the reference gap, By inserting a sealed letter containing the same number of contents as the sealed letter inserted in the measurement gap as a reference article in the reference gap, it is possible to make a pass / fail judgment with respect to the reference object reliably and easily. Confirmation (measurement work) of the number of sealed letters supplied to the printer can be performed more efficiently.

  According to the measurement device of claim 4, the three electrodes forming the two gaps of the measurement gap and the reference gap, the measurement circuit for measuring the physical quantities of the measurement gap and the reference gap, respectively, and the two gaps It is equipped with a judgment means that determines at least one of the number, thickness, or material of the contents contained in the sealed letter by measuring the physical quantity and obtaining the ratio thereof, so that the measurement gap can be measured regardless of environmental changes. The physical quantity of the sealed letter and the physical quantity of the reference gap can be measured with high accuracy, the number of contents etc. can be measured accurately without opening the sealed letter, etc. The number of contents can be easily measured.

  Further, according to the invention described in claim 5, in addition to the effect of the invention described in claim 4, the measurement gap and the reference gap are made the same by arranging the three electrodes in a stacked state or a juxtaposed state. Because the environment is set, the environment of both gaps can be set to the same environment regardless of temperature, humidity, etc., and the number of contents of the sealed letter inserted in the measurement gap can be measured with higher accuracy. .

  Further, according to the invention described in claim 6, in addition to the effect of the invention described in claim 4 or 5, the measurement circuit functions as a signal processing circuit of the differential capacitive sensor, and therefore is inserted in the measurement gap. Capacitance can be used as the physical quantity of the sealed letter and the physical quantity of the reference gap, and the number of sheets can be measured with higher accuracy by the capacitance according to the number of contents.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 6 show a first embodiment of a measuring apparatus according to the present invention, FIG. 1 is a basic configuration diagram thereof, FIG. 2 is an explanatory diagram of an electrode portion, FIG. 3 is a circuit diagram of a signal processing circuit, and FIG. Fig. 5 is a waveform diagram, Fig. 5 is a schematic configuration diagram of a sealed letter batch processor incorporating a measuring device, and Fig. 6 is a graph showing the relationship between the number of contents and the output voltage.

  As shown in FIG. 1, a measuring apparatus 1 includes an electrode 2, a signal processing circuit 3 as a measurement circuit connected to the electrode 2, a determination circuit 4 as a determination means connected to the signal processing circuit 3, and the like. It has. The electrode 2 is composed of a first electrode 2 a to a third electrode 2 c that are fixedly arranged in a stacked state in the vertical direction, and the first electrode 2 a and the second electrode 2 b are in a horizontal state at a predetermined interval by the electrode support 5. The first electrode 2a and the third electrode 2c are supported in a horizontal state by, for example, a case-like electrode support 6. The electrode supports 5 and 6 are made of the same material, and are set to thermally expand, for example, by the same amount according to environmental changes such as temperature. Each electrode 2 is connected to one end of a coaxial cable 7 whose external line is grounded, and the other end of each cable 7 is connected to a predetermined input terminal of the signal processing circuit 3. 3 and the determination circuit 4 are connected by a predetermined cable 8.

  Each electrode 2 is formed in the same shape by a copper plate or the like having a rectangular outer shape and a predetermined plate thickness, as shown in FIG. A reference gap K1 is formed between the first electrode 2a and the second electrode 2b, and a measurement gap K2 is formed between the second electrode 2b and the third electrode 2c. As a result, the measurement gap K2 and the reference gap K1 are set close to each other in the vertical direction, and as shown in FIG. 2B, a capacitance C1 using air as a dielectric is created in the reference gap K1. Thus, a capacitance C2 using air as a dielectric is formed in the measurement gap K2.

  As shown in FIG. 3, the signal processing circuit 3 includes an interface circuit 11 including a differential capacitive sensor 10. The interface circuit 11 includes a -1 × amplifier A3, an inverting amplifier A1, four resistors R1, R2, R3, and R4 having the same size, an oscillator 12, and the like. The circuit 13 in the broken line portion is provided in order to prevent charges from being accumulated in the voltage of the positive phase input terminal of the operational amplifier A1 due to the bias current flowing into the input of the operational amplifier A1.

As shown in FIG. 4, the interface circuit 11 has an output voltage vo, and when a predetermined square wave vosc is input, vosc becomes positive by the action of the analog switch and the clock signals φa and φb. The voltage is stored in each capacitor by setting vo at the time of vo as vo and vo when vosc becomes negative as vob. And it is computed and output as the following formula 1 by a computing unit (not shown). Further, as will be described later, when the sealed letter 9 (refer to FIGS. 1 and 5) as the object to be measured passes through the measurement gap K2, the differential capacitance sensor 10 functions in the interface circuit 11, and the voltage displacement amount If Δvo is output and, for example, the input square wave vosc changes by Δvosc, the voltages v1, v2, and vo also change by Δv1, Δv2, and Δvo, respectively.
v-out = voa-vob (Equation 1)

Further, since the inverting input terminal of the operational amplifier A1 is a virtual ground point, the voltage is always constant at 0v, and the charge ΔQ flowing into the inverting input terminal of the operational amplifier A1 does not always change (= 0). Output (voltage obtained by adding an offset voltage) is obtained. By adding an analog switch circuit for canceling the offset voltage in the processing circuit after output, the values of voa and vob can be obtained, and the output value of v-out = voa-vob can be obtained. Thus, the output shown in Equation 3 is obtained. Further, the change Δv-out of the output voltage when the object to be measured passes is 2Δvo.
vo = {(C2-C1) / (C2 + C1)} vosc + [offset voltage] (Equation 2)
v-out = {(C2-C1) / (C2 + C1)} [amplitude of vosc] (Equation 3)

  The determination circuit 4 shown in FIG. 1 includes a storage unit, a determination unit, and the like (not shown) configured by, for example, a microcomputer. The storage unit includes a table relating to the output voltage and the number of contents of the sealed letter 9 described later, and an output. The number of contents determined (measured) based on the voltage and the table is stored.

  Next, an example of a specific configuration and operation of the measuring apparatus 1 will be described with reference to FIGS. As shown in FIG. 5, the sealed letter batch processor 14 in which the measuring apparatus 1 of the present invention is incorporated has upstream and downstream sealed letters formed of a belt conveyor or the like on both sides in the longitudinal direction of the third electrode 2c of the measuring apparatus 1. The feeding mechanisms 15a and 15b are installed in a horizontal state, a pre-processed sealed letter storage section 16 is provided above the start end of the upstream sealed letter feeding mechanism 15a, and processed at the lower end of the downstream sealed letter feeding mechanism 15b. A sealed letter receiving unit 17 is provided.

  Then, in the initial state where the sealed letter 9 is not inserted in the measurement gap K2 of the measuring apparatus 1, the sealed letter batch processing machine 14 stores the sealed letter 9 stored in the pre-processed sealed letter processing unit 16 one by one on the upstream side. Supplied to the feeding mechanism 15a, conveyed downstream by the feeding mechanism 15a, and fed into the measurement gap K2 of the measuring apparatus 1 from its end portion. When the sealed letter 9 is fed into the measurement gap K2 and inserted, the measurement apparatus 1 is activated and the capacitance C2 of the measurement gap K2 is measured by the second electrode 2b and the third electrode 2c. Simultaneously with the capacitance C2 of the measurement gap K2, the capacitance C1 of the reference gap K1 is also measured by the first electrode 2a and the second electrode 2b. It should be noted that the measurement of the capacitance C1 of the reference gap K1 is not simultaneous with the measurement gap K2, but can of course be measured in advance.

When the capacitances C1 and C2 of the gaps K1 and K2 are measured, they are output from the output terminal of the signal processing circuit 3 and input to the determination circuit 4, and the determination circuit 4 receives the input both capacitances. Based on C1 and C2, the output voltage is calculated by the following equation 4. At this time, the calculated output voltage is obtained by the ratio of the measured values of both capacitances C1 and C2, and therefore is not affected by environmental changes such as the temperature and humidity at the measurement location.
Output voltage = constant × (C1-C2) / (C1 + C2) (Equation 4)

  When the output voltage is calculated based on Expression 4, the determination unit of the determination circuit 4 determines (measures) the number of contents of the sealed letter 9 based on the output voltage. For this determination, a table showing the correlation between the number of sheets and the output voltage, for example, as shown in FIG. For example, when the output voltage is 60 mV, the number of sheets is determined to be two, and when the output voltage is 90 mV, the number of sheets is determined to be eight. In the table of FIG. 6, as the output voltage corresponding to each number of sheets, a value of a predetermined width that does not overlap in the adjacent number of sheets is used, and this table is installed at the installation place where the sealed letter batch processor 14 is installed. It is preferable from the viewpoint of accuracy improvement that it is initially obtained and stored in the storage unit of the determination circuit 4.

  When the determination unit of the determination circuit 4 determines the number of contents of the sealed letter 9 that has passed through the measurement gap K2, the determination result is stored in the storage unit of the determination circuit 4. At this time, the number of sheets stored in the storage unit is stored by being linked to each sealed letter 9 continuously supplied from the upstream sealed letter feeding mechanism 15a to the measurement gap K2, and all these data are stored as necessary. The data is taken out from the storage unit of the determination circuit 4.

  For example, when the number of contents of the sealed letter 9 containing the same number of contents is checked in the sealed letter batch processor 14, a defective number of unsealed letters (not shown) is placed at a predetermined position of the downstream letter feeding mechanism 15b. What is necessary is just to set it as the structure which provides a discharge part and discharges the sealed letter in which the number defect was measured by the measuring apparatus 1 to this number defective letter discharge part. If comprised in this way, only the sealed letter 9 in which the same number of contents were accommodated in the processed sealed letter receiving part 17 can be stocked. Further, the apparatus into which the measuring apparatus 1 is incorporated is not limited to the above-described package batch processing machine 14 or the like for confirming the number of sealed contents, but is incorporated into a part of a batch processing machine or the like that seals the contents in the sealed letter 9, for example. You can also.

  As described above, in the measurement apparatus 1 of the above embodiment, the first electrode 2a to the third electrode 2b forming the two gaps of the measurement gap K2 and the reference gap K1, and the static of the measurement gap K2 and the reference gap K1. The signal processing circuit 3 for measuring the capacitances C1 and C2, respectively, and the number of contents contained in the sealed letter 9 by obtaining a ratio based on the measured capacitances C1 and C2 of the two gaps K1 and K2. Since the determination circuit 4 is provided, the electrostatic capacity C2 of the sealed letter 9 in the measurement gap K2 and the electrostatic capacity C1 of the reference gap K1 can be measured in the same measurement environment, and the electrostatic capacity of the measurement gap K2 and the reference gap K1 can be measured. Since the ratio is determined by determining the ratio of the capacitances C1 and C2, the capacitances C1 and C2 of the gaps K1 and K2 can be measured with high accuracy without being affected by the environment.

  In addition, since the first electrode 2a to the third electrode 2b are arranged close together in the vertical direction (thickness direction), the environment in both the gaps K1, K2 is always the same regardless of the temperature, humidity, etc. Since the electrode supports 5 and 6 that support the first electrode 2a to the third electrode 2c are formed of the same material, the thermal expansion and the like can be set to be the same, and the measurement gap K2 and the reference The degree of deformation of the gap K1 with respect to heat or the like can be made substantially the same, and the environment of both the gaps K2 and K1 can always be kept constant. Thus, the number of contents can be accurately measured without opening the sealed letter 9, and the number of contents can be easily measured simply by inserting the sealed letter 9 in the measurement gap K2. It becomes possible.

  Further, since the signal processing circuit 3 includes the interface circuit 11 that processes the signal of the differential capacitance sensor 10 formed by the first electrode 2a to the third electrode 2c, a sealed letter inserted in the measurement gap K2. An electrostatic capacity can be used as the physical quantity of 9, and the number can be measured with higher accuracy by the electrostatic capacity C2 corresponding to the number of contents. In addition, since the number of sheets is measured by measuring both the capacitances C1 and C2 of the measurement gap K2 and the reference gap K1, it is not necessary to use a large current for the measurement apparatus 1 itself, and the use of the coaxial cable 7 Effective noise countermeasures can be easily taken. In particular, by arranging the signal processing circuit 3 near the electrode 2, the length of the coaxial cable 7 can be shortened, a reliable noise countermeasure can be taken, and the measuring apparatus 1 excellent in safety and reliability. Can be provided.

  Moreover, according to the sealed letter batch processor 14 using the measuring apparatus 1 of the present invention, the sealed letter 9 is continuously fed into the measuring gap K2 one by one by the sealed letter feeding mechanism 15a and is passed through the measuring gap K2. Since the number of items is automatically measured, the measurement of the contents of a large number of sealed letters 9 can be processed at one time. For example, the number of contents of the sealed letters 9 can be checked and the contents sealed in the sealed letters 9 can be efficiently processed. Can be processed automatically.

  Note that the signal processing circuit 3 in the measurement apparatus 1 is not limited to the interface circuit 11 shown in FIG. 3, and for example, the interface circuit 18 shown in FIGS. 7 and 8 can be used. This interface circuit 18 includes an operational amplifier A1 as a comparator, and an operational amplifier A2 as an adder and an integrator. The differential circuit portion of the operational amplifier is also used as an inverting input addition circuit. In addition to acting as an adder circuit together with the inverting amplifier circuit, the excitation signal can be supplied from within the circuit by adding a comparator instead of introducing the excitation signal from an external circuit to create a relaxation oscillation circuit in combination with an integrator. It is a thing.

In the case of this interface circuit 18, as shown in FIG. 8, the excitation signal voltage v1 is a square wave having a period of T, and the current flowing through the capacitor C1 is the current flowing through the resistors R1 and R3 and flows through the capacitor C2. The current is a current that also flows through the resistors R2 and R4. Since vout = −v4 and C1 and C2 are connected to the virtual ground point of the operational amplifiers A3 and A2 and the point of v2, the current flowing through C2 is (C2 / C1) times the current flowing through C1. Become. As a result, an output voltage of the following equation 5 is obtained, and the output voltage vout is output as a square wave shown in FIG.
vout = {(C2-C1) / (C2 + C1)} v1 (Equation 5)

  According to this circuit configuration, it is possible to prevent V2 from saturating the power supply voltage without adding a new detection circuit, and the capacitance of the transducer is connected to the output part of the operational amplifier or the virtual ground point, so that the ratiometric The influence of the parasitic capacitance on the processing can be minimized. As described above, as the signal processing circuit 3 according to the present invention, various circuits capable of ratiometric processing of differential capacitance type sensor signals can be used.

  In the measuring apparatus 1 of the first embodiment, the first electrode 2a to the third electrode 2c are all formed to have the same size. For example, as shown in FIG. 9, the second electrode 2b is used as the first electrode. You may set slightly smaller than 2a and the 3rd electrode 2c. With this configuration, the entire surface of the second electrode 2b forming both the measurement gap K2 and the reference gap K1 always corresponds to the first electrode 2a and the third electrode 2c, and the gaps K1 and K2 are always the same. It can be easily set to the environment. The forms of the first electrode 2a to the third electrode 2c can also be applied to the first electrode 2a to the third electrode 2c of the second embodiment to be described later.

  10 and 11 show a second embodiment of the measuring apparatus according to the present invention. Hereinafter, the same parts as those in the first embodiment will be described with the same reference numerals. The characteristic of the measuring apparatus 1 of this embodiment is that the first electrode 2a to the third electrode 2c forming the electrodes are not all stacked in the vertical direction, but the first electrode 2a to the third electrode 2c are planarized. The measurement gap K2 and the reference gap K1 are provided close to each other in the plane direction.

  In other words, the first electrode 2a and the third electrode 2c are arranged in a horizontal state in the proximity of each other, and the second electrode 2b is placed in a horizontal state with a predetermined gap dimension above the adjacent portions of both the electrodes 2a and 2c. Deploy. Thereby, the reference gap K1 is formed by the substantially right half of the first electrode 2a and the substantially left half of the second electrode 2b, and the measurement gap K2 is formed by the substantially left half of the third electrode 2c and the substantially right half of the second electrode 2b. Will be formed. In the case of this measuring device 19, as shown in FIG. 11 (a), the sealed letter 9 is inserted between the measuring gaps K2 as indicated by the arrow A, and the capacitance of the sealed letter 9 is measured. It will be. Also in the measuring apparatus 1 of the second embodiment, the measurement gap K2 and the reference gap K1 can be arranged close to each other, and the same effect as the first embodiment can be obtained. Therefore, it is possible to reduce the thickness of the measuring apparatus 1.

  By the way, in this embodiment, the case where the dielectric is only air without inserting an object in the reference gap K1 has been described. However, for example, a reference object serving as a pass / fail reference is always inserted in the reference gap K1. Thus, the number of contents in the sealed letter 9 may be determined with high accuracy. That is, as shown by a two-dot chain line in FIG. 10, the reference object 20 containing the same number of contents as the sealed letter 9 inserted in the measuring gap K2 is fixed in the reference gap K1 before the measurement of the sealed letter 9 is started. Set with.

  Then, with the reference object 20 set in the reference gap K1, the sealed letter 9 to be measured is sequentially supplied and inserted into the measurement gap K2, the capacitance C2 is measured, and the reference object 20 is inserted in advance. The capacitance C1 of the reference gap K1 is measured, and the number of sealed letters 9 inserted in the measurement gap K2 is determined (measured) based on the ratio between the capacitances C1 and C2. In this determination, since the reference object 20 is inserted in the reference gap K1, it is determined whether it is substantially the same or not the same as the number of the reference object 20, that is, confirmation of the number of envelopes 9 in the measurement gap K2 ( The number of sheets is accepted or rejected).

  The reference object 20 in this measurement method is formed of, for example, a long reference object shown in FIG. 12, and the contents of 2, 4, 6, 8, 10 are shown in FIG. 12 (b). It has the reference | standard part 20a, 20b, 20c, 20d, 20e of the same form as the sealed letter 9 in which each thing was accommodated. Then, the reference portions 20a to 20d of the reference object 20 move in the direction of the arrow B as shown in FIG. 12 (a) according to the number of contents of the sealed letter 9 as the measurement object supplied to the measurement gap K2. Thus, the reference gap K1 is set and used in a fixed state.

  As a result, one reference object 20 can be used for determining the number of envelopes 9 of various numbers, and the efficiency of measurement work can be improved. The reference object 20 is not limited to the illustrated example, and a reference object consisting of a single sealed letter 9 corresponding to a predetermined number of sheets may be used in advance. Of course, it is also possible to use a reference material. Needless to say, the measuring method using the reference object 20 can also be applied to the measuring apparatus 1 shown in FIG.

  In each of the above-described embodiments, the example in which the contents in the sealed letter 9 are measured (determined) using paper as the content has been described. However, the measuring apparatus 1 according to the present invention has been found to have a material (dielectric constant), for example. One sheet of paper is inserted into the reference gap K1 to measure the thickness of the paper inserted into the measurement gap K2, or a plurality of sheets of known material are inserted into the reference gap K1 to measure the gap K2. It is also possible to measure the thickness (that is, the number of sheets) of the paper inserted in the sheet. In addition, after inserting two types of paper, each of which has a known capacitance, into the reference gap K1, it is possible to measure which type of paper is inserted into the measurement gap K2, that is, to measure the material of the paper. In these cases, it is not limited to the single measurement of the number, thickness, or material of the contents, but at least one of the number, material, thickness and material is measured at the same time, or all of the number, thickness, and material are measured simultaneously. What is necessary is just to comprise so that it can measure.

  In addition, the contents as the object to be measured in the present invention are not limited to paper, but can be similarly applied to various contents such as plastic such as a card, cloth, or a combination thereof. Furthermore, the present invention is not limited to the measurement of the number, thickness, material, etc. of objects to be measured inserted into the measurement gap K2 based on the capacitance C1 of the reference gap K1, for example, an object whose thickness is known is used as a reference. The present invention can be applied to an apparatus for measuring the dielectric constant of an object to be measured inserted in the gap K1 and measuring the dielectric constant of the object to be measured. When it is known, the present invention can also be applied to an apparatus for measuring a change in capacitance, a distance between an object to be measured and an electrode when passing an object to be measured having a dimension and material passed through the measurement gap K2.

  Furthermore, the shape of the electrode 2 and the configuration of the measurement circuit 3 and the determination circuit 4 in each of the above embodiments are also examples. For example, the shape of the first electrode 2a to the third electrode 2c is a rhombus or a circle in plan view. The measurement circuit 3 and the determination circuit 4 are formed on a single printed circuit board to form a single electronic component, etc., and may be changed as appropriate without departing from the scope of the present invention. Can do.

  The present invention can be applied not only to a measuring device that uses a capacitance as a physical quantity for measuring the number of contents of a sealed letter, but also to a measuring device that uses a physical quantity such as resistance or inductance.

1 is a schematic configuration diagram showing a first embodiment of a measuring apparatus according to the present invention. Illustration of the electrode part Circuit diagram of the signal processing circuit Waveform diagram Schematic configuration diagram of sealed letter batch processing machine incorporating the same measuring device Graph showing the relationship between the same number and output voltage Circuit diagram showing a modification of the signal processing circuit Waveform diagram A perspective view and a plan view showing a modification of the electrode The schematic block diagram which shows 2nd Embodiment of the measuring apparatus concerning this invention. The explanation part of the electrode part Explanatory drawing showing a modification of the same measurement method Schematic configuration diagram showing a conventional measuring device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Measuring device 2 ... Electrode 2a ... 1st electrode 2b ... 2nd electrode 2c ... ······ Third electrode 3 ········································································ 5 ······ Cable 9 ········································································································ Interface circuit 12 ... Oscillator 14 ... Sealed letter batch processing machine 15a, 15b ... Sealed letter feeding mechanism 16 ... ... Pre-processed sealed letter storage part 17 ... ... Process Sealed letter receiving unit 18 ... Interface circuit 20 ... Reference object 20a to 20e ... Reference part K1 ... Reference gap K2 ...・... measurement gap C1, C2 ····· capacitance

Claims (6)

  Two gaps of a measurement gap and a reference gap are formed by three electrodes having a predetermined gap, and a physical quantity is measured by inserting a sealed letter containing a predetermined number of contents in the measurement gap, and the reference gap is measured. A method for measuring sealed contents, characterized in that a physical quantity is measured and a ratio of both measured physical quantities is determined to determine at least one of the number, thickness, and material of the contents contained in the sealed letter.   The method for measuring sealed contents according to claim 1, wherein the sealed letter is inserted into the measurement gap by passing from one end opening to the other end opening of the measurement gap.   The method for measuring sealed contents according to claim 1 or 2, wherein a physical quantity of the measurement gap is measured in a state in which a reference object is inserted in the reference gap.   Three electrodes that are arranged with a predetermined interval to form two gaps of a measurement gap and a reference gap, a measurement circuit that measures a physical quantity of the two gaps, a measurement gap measured by the measurement circuit, and a reference An apparatus for measuring the contents of a sealed letter, comprising: a determination unit that obtains a ratio of each physical quantity of the gap and determines at least one of the number, thickness, and material of the contents contained in the sealed letter.   The three electrodes are laminated in the thickness direction or arranged side by side in the plane direction so that the measurement gap and the reference gap are arranged close to each other, and both gaps are set in the same environment. The measuring apparatus for sealed contents according to claim 4.   6. The sealed content measuring apparatus according to claim 4, wherein the measuring circuit functions as a signal processing circuit of a differential capacitance type sensor.

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