JP2021135152A - Basis weight measuring device and method for measuring basis weight - Google Patents

Abstract

To provide a basis weight measuring device which can measure the basis weight of a target measurement object with a relatively simple configuration.SOLUTION: A basis weight measuring device 1 for measuring the basis weight of a target measurement object includes: a substrate 110; a lens holder 120 arranged on the substrate 110; a lens 130 arranged on an upper surface of the lens holder 120; a light emitting element 140; a first light reception element 151 for receiving a first reflected light from the lens holder 120 of an irradiation light from the light emitting element 140; a second light reception element 152 for receiving a P-wave component of a second reflected light from the target measurement object of an irradiation light from the light emitting element 140; a third light receiving element 153 for receiving an S-wave component of the second reflected light; and a measurement unit 200 for calculating a dummy transmission light of the target measurement object by subtracting the P-wave component and the S-wave component of the second reflected light from the first reflected light, and measuring a basis weight on the basis of a dummy transmission light.SELECTED DRAWING: Figure 1

Description

The present invention relates to a basis weight measuring device and a basis weight measuring method.

Conventionally, as a basis weight measuring device for measuring the basis weight of a measurement object such as printing paper, for example, the one described in Patent Document 1 and the one described in Patent Document 2 are known.

A printing paper having a high surface gloss has a larger amount of reflected light (normal reflected light and diffuse reflected light) from the printing paper than a printing paper having a normal gloss, while transmitting through the printing paper. The amount of light tends to decrease. The basis weight measuring device described in Patent Document 1 utilizes this tendency and corrects the reduced amount of transmitted light by using the increased amount of reflected light to correct the basis weight of printing paper having different surface glossiness. Can be discriminated.

The basis weight measuring device described in Patent Document 2 receives the P-wave component of the internal diffusely reflected light from the printing paper with a receiver while blocking the diffusely reflected light from the printing paper with a polarizing filter. The basis weight of the printing paper is measured based on the P wave component of the diffusely reflected light.

Japanese Unexamined Patent Publication No. 2019-82433 Japanese Unexamined Patent Publication No. 2018-13487

Since the basis weight measuring device described in Patent Document 1 is composed of two sensor units, the size of the device is increased and the manufacturing cost is increased. Similarly, in the basis weight measuring device described in Patent Document 2, since it is necessary to arrange a polarizing filter on the optical path that guides the internally diffuse reflected light to the receiver, the device becomes large in size and the manufacturing cost increases. ..

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a basis weight measuring device and a basis weight measuring method capable of measuring the basis weight of a measurement object with a relatively simple configuration. There is.

In order to solve the above problems, the basis weight measuring device according to the present invention is
A basis weight measuring device that measures the basis weight of an object to be measured.
With the board
A lens holder arranged on the substrate and forming a first accommodation space and a second accommodation space separated from each other on the substrate.
The lens arranged on the upper surface side of the lens holder and
A light emitting element arranged on the substrate in the first accommodation space and
A first light receiving element, which is arranged on the substrate in the first accommodation space and receives the first reflected light from the lens holder with respect to the irradiation light of the light emitting element.
A second light receiving element arranged on the substrate of the second accommodating space and receiving a P wave component of the second reflected light from the measurement object with respect to the irradiation light, and a second light receiving element.
A third light receiving element arranged on the substrate in the second accommodating space and receiving an S wave component of the second reflected light, and a third light receiving element.
A measurement in which the P-wave component and the S-wave component of the second reflected light are subtracted from the first reflected light to calculate the pseudo-transmitted light of the measurement object, and the basis weight is measured based on the pseudo-transmitted light. Department and
It is characterized by having.

According to this configuration, the sensor configuration in which the light emitting element and the first to third light receiving elements are arranged on the substrate, that is, the basis weight of the object to be measured can be measured by one reflective sensor, so that the size of the device can be increased. It is possible to suppress an increase in manufacturing cost.

In the above basis weight measuring device
The measuring unit can be configured to control the light emitting element so that the amount of the irradiation light becomes constant based on the measurement result of the first light receiving element.

In the above basis weight measuring device
The measuring unit can be configured to measure the glossiness of the object to be measured based on the measurement results of the second light receiving element and the third light receiving element.

In order to solve the above problems, the basis weight measuring method according to the present invention is
It is a basis weight measuring method that measures the basis weight of the object to be measured using a reflective sensor.
An irradiation step of irradiating the object to be measured with the irradiation light of the light emitting element of the reflection type sensor via a lens arranged on the upper surface side of the lens holder of the reflection type sensor.
A first light receiving step of measuring the first reflected light from the lens holder with respect to the irradiation light by the first light receiving element of the reflective sensor, and a first light receiving step.
A second light receiving step of measuring the P wave component of the second reflected light from the measurement object with respect to the irradiation light by the second light receiving element of the reflective sensor.
A third light receiving step for measuring the S wave component of the second reflected light by the third light receiving element of the reflective sensor, and a third light receiving step.
Pseudo-transmitted light of the object to be measured is calculated by subtracting the P-wave component and the S-wave component of the second reflected light from the first reflected light, and the basis weight is measured based on the pseudo-transmitted light. With the quantity measurement step,
It is characterized by including.

According to this configuration, the basis weight of the object to be measured can be measured by using one reflective sensor including a light emitting element and the first to third light receiving elements, so that it is possible to suppress an increase in the size of the device and an increase in manufacturing cost. be able to.

The above basis weight measurement method is
Based on the measurement result of the first light receiving element, the light emitting control step for controlling the light emitting element so that the amount of the irradiation light becomes constant can be included.

The above basis weight measurement method is
It can be configured to include a glossiness measurement step for measuring the glossiness of the object to be measured based on the measurement results of the second light receiving element and the third light receiving element.

According to the present invention, it is possible to provide a basis weight measuring device and a basis weight measuring method capable of measuring the basis weight of an object to be measured with a relatively simple configuration.

It is a figure which shows the basis weight measuring apparatus which concerns on this invention. It is a partial plan view of the substrate of the basis weight measuring apparatus which concerns on this invention. It is a figure for demonstrating the principle of basis weight measurement which concerns on this invention.

Hereinafter, embodiments of the basis weight measuring device and the basis weight measuring method according to the present invention will be described with reference to the accompanying drawings.

[Basis weight measuring device]
FIG. 1 shows a basis weight measuring device 1 according to an embodiment of the present invention. The basis weight measuring device 1 is composed of a reflection type sensor 100 and a control circuit 200. The basis weight measuring device 1 is used as a media sensor for discriminating the type of printing paper (corresponding to the “measurement object” of the present invention) in an image forming device such as a laser printer or a multifunction device.

The reflective sensor 100 includes a substrate 110, a lens holder 120, a lens 130, a light emitting element 140, a first light receiving element 151, a second light receiving element 152, a third light receiving element 153, and a signal processing circuit 160. , Equipped with.

The board 110 is, for example, a rectangular printed wiring board. As shown in FIG. 2, on the upper surface of the substrate 110, a light emitting element 140, a first light receiving element 151, a second light receiving element 152, a third light receiving element 153, and a signal processing circuit 160 are formed on the longitudinal surface of the substrate 110. Arranged side by side in the direction. Further, the substrate 110 is provided with a through groove into which a part of the lens holder 120 is fitted.

The lens holder 120 is made of a material that is opaque to the irradiation light of the light emitting element 140 and reflects the irradiation light. The lens holder 120 is arranged on the upper surface of the substrate 110, and has a first accommodating portion 121, a second accommodating portion 122, and a third accommodating portion 123 on the lower surface side.

The first accommodating portion 121 forms a first accommodating space on the substrate 110. The light emitting element 140 and the first light receiving element 151 are accommodated in the first accommodation space. The second accommodating portion 122 forms a second accommodating space on the substrate 110. The second light receiving element 152 and the third light receiving element 153 are housed in the second accommodating space. The third accommodating portion 123 forms a third accommodating space on the substrate 110. A signal processing circuit 160 is arranged in the third accommodation space. The first accommodation space, the second accommodation space, and the third accommodation space are separated from each other. By separating the accommodation space of the light receiving elements 151 to 153 and the signal processing circuit 160 in this way, it is possible to prevent light from being reflected by the signal processing circuit 160 such as a signal processing chip and entering the light receiving elements 151 to 153. can.

The lens holder 120 has a lens fixing portion 124 on the upper surface side. Although omitted in FIG. 1, the lens fixing portion 124 is configured to have a shape capable of fixing the lens 130.

Further, the lens holder 120 is placed between the first opening 125 connected to the first accommodating portion 121, the second opening 126 connected to the second accommodating portion 122, and the first opening 125 and the second opening 126. It has a light-shielding portion 127 located.

The first opening 125 is located above the light emitting element 140 and functions as a diaphragm portion that limits the irradiation range of the irradiation light of the light emitting element 140. A first polarizing filter 171 is provided at the upper end of the first opening 125. The first polarizing filter 171 is a polarizing filter for P wave transmission that shields the S wave component of the irradiation light and transmits the P wave component.

The second opening 126 is formed to have substantially the same size as the second accommodating portion 122. The second opening 126 and the second accommodating portion 122 may be composed of one through hole. A second polarizing filter 172 is provided at the upper end of the second opening 126. The second polarizing filter 172 is composed of a P wave transmitting polarizing filter located above the second light receiving element 152 and an S wave transmitting polarizing filter located above the third light receiving element 153. The polarizing filter for S wave transmission blocks the P wave component of the reflected light from the object to be measured and transmits the S wave component.

The light-shielding portion 127 is provided so that the upper portion protrudes into the lens 130 and can block the irradiation light propagating in the lens 130, while the lower portion is fitted into the through groove of the substrate 110 and the inside of the substrate 110. It is possible to block the propagating irradiation light.

The lens 130 is made of a material that is transparent to the irradiation light of the light emitting element 140, and is fixed to the lens fixing portion 124 of the lens holder 120. The lens 130 has a convex lens portion 131 on the upper surface side, and has a light emitting lens portion 132 and a light receiving lens portion 133 on the lower surface side.

The convex lens portion 131 faces the light emitting lens portion 132 and the light receiving lens portion 133 on the lower surface side. The upper surface of the convex lens portion 131 is flat, and the length of the convex lens portion 131 in the width direction (short direction) is larger than the length of the light-shielding portion 127 in the width direction.

The light emitting lens unit 132 is located above the light emitting element 140 to collect the irradiation light of the light emitting element 140, while the light receiving lens unit 133 is located above the second light receiving element 152 and the third light receiving element 153. Condenses the reflected light from the object to be measured. The light emitting lens portion 132 is formed at a position higher than that of the light receiving lens portion 133 because the light is focused through the tubular opening (first opening 125) of the lens holder 120.

Under the control of the control circuit 200, the light emitting element 140 irradiates the object to be measured with irradiation light via the first polarizing filter 171 and the lens 130. As the light emitting element 140, for example, an infrared light emitting diode (infrared LED) that irradiates infrared rays or a red light emitting diode (red LED) that irradiates red light can be used.

The first light receiving element 151 receives the first reflected light from the lens holder 120 with respect to the irradiation light of the light emitting element 140. That is, the irradiation light of the light emitting element 140 includes light that passes through the first opening 125 and is irradiated to the object to be measured, and light that is reflected in the first accommodating portion 121 (first reflected light). In addition, in order to prevent the direct light from entering the first light receiving element 151 from the light emitting element 140, a shield such as a protrusion may be provided between the light emitting element 140 and the first light receiving element 151. In the present embodiment, the amount of light emitted to the object to be measured and the amount of light of the first reflected light are about the same. The first light receiving element 151 outputs a current signal corresponding to the amount of received light of the first reflected light to the signal processing circuit 160. As the first light receiving element 151, for example, a photodiode or a phototransistor can be used.

The second light receiving element 152 receives the P wave component of the reflected light (second reflected light) from the object to be measured with respect to the irradiation light, and outputs a current signal corresponding to the amount of received light to the signal processing circuit 160. The third light receiving element 153 receives the S wave component of the second reflected light and outputs a current signal corresponding to the received light amount to the signal processing circuit 160. As the second light receiving element 152 and the third light receiving element 153, for example, a photodiode or a phototransistor can be used.

In the present embodiment, the light emitting element 140, the first light receiving element 151, the second light receiving element 152, and the third light receiving element 153 are mounted on the substrate 110 as bare chips that are not packaged (resin-sealed). As a result, the size of the entire sensor can be reduced.

The signal processing circuit 160 includes a voltage signal (first output signal) corresponding to the current signal of the first light receiving element 151, a voltage signal (second output signal) corresponding to the current signal of the second light receiving element 152, and a third. A voltage signal (third output signal) corresponding to the current signal of the light receiving element 153 is generated and output to the control circuit 200.

The signal processing circuit 160 includes, for example, a plurality of current amplifier circuits composed of operational amplifiers. The signal processing circuit 160 includes a differential amplifier circuit, generates a voltage signal corresponding to the amount of positively reflected light of the second reflected light corresponding to the potential difference between the second output signal and the third output signal, and generates the voltage. The signal may be output to the control circuit 200.

The control circuit 200 corresponds to the "measuring unit" of the present invention, and has a basis weight measuring unit for measuring the basis weight of the object to be measured, a glossiness measuring unit for measuring the glossiness of the object to be measured, and an amount of irradiation light. A light emitting control unit for controlling the light emitting element 140 so as to be constant is provided. The control circuit 200 is composed of, for example, a microcomputer.

As shown in FIG. 3, the basis weight measuring unit measures the basis weight of the object to be measured based on the pseudo transmitted light Vt'which is a pseudo calculation of the transmitted light Vt of the object to be measured with respect to the irradiation light V (I). do. The pseudo transmitted light Vt'is obtained by subtracting the P wave component V (P) and the S wave component V (S) of the second reflected light from the first reflected light V (R) as shown in the following equation (1). Is calculated by. V (R) is calculated based on the first output signal, and V (P) and V (S) are calculated based on the second output signal and the third output signal.

Since the transmitted light Vt and the basis weight have a correlation, and the transmitted light Vt and the pseudo transmitted light Vt'have a correlation (in the present embodiment, the values are almost the same), the pseudo transmitted light Vt'and the basis weight have a correlation. Has a correlation. Therefore, the basis weight measuring unit can measure the basis weight based on the pseudo transmitted light Vt'.

Since the internally diffuse reflected light Vi of the object to be measured is so small that it can be ignored, the internal diffuse reflected light Vi is not taken into consideration when calculating the pseudo-transmitted light Vt'in this embodiment. As a result, the light receiving element that detects the pseudo transmitted light Vt'can be omitted, so that the size of the entire sensor can be reduced.

If the internal diffuse reflection light Vi for each type of the object to be measured can be measured in advance, the measured Vi is stored in the basis weight measuring unit, and V (R) to V (P), V (S), Pseudo-transmitted light Vt'may be calculated by subtracting Vi.

In the present embodiment, the amount of irradiation light V (I) irradiated to the object to be measured and the amount of light of the first reflected light V (R) are about the same, but if there is a difference between the two, the difference is the difference. It is preferable to correct the first reflected light V (R) accordingly and apply the corrected first reflected light V (R) to the above equation (1). For example, even if the light amount of the irradiation light V (I) and the light amount of the first reflected light V (R) are measured in advance to calculate the correction coefficient, and the first reflected light V (R) is corrected by the calculated correction coefficient. good.

The glossiness measuring unit measures the glossiness of the object to be measured based on the reflected light (second reflected light) from the object to be measured with respect to the irradiation light. For example, the glossiness measuring unit responds to the amount of specularly reflected light (P wave component in this embodiment) of the second reflected light based on the potential difference between the second output signal and the third output signal. The glossiness of the object to be measured is measured based on the voltage signal.

The light emission control unit feedback-controls the light emitting element 140 so that the amount of irradiation light of the light emitting element 140 becomes constant based on the first output signal. In the present embodiment, one first light receiving element 151 functions as a sensor element for performing feedback control of the light emitting element 140, and also functions as a sensor element for measuring the basis weight of the object to be measured. Therefore, the size of the entire device can be reduced.

[Basis weight measurement method]
The basis weight measuring method according to the embodiment of the present invention is performed by the basis weight measuring device 1, and includes an irradiation step, a first light receiving step, a second light receiving step, a third light receiving step, and a basis weight measuring step. , Including a glossiness measuring step and a light emission control step.

In the irradiation step, the irradiation light of the light emitting element 140 is irradiated to the object to be measured through the first polarizing filter 171 and the lens 130.

In the first light receiving step, the first light receiving element 151 receives the first reflected light from the lens holder 120 with respect to the irradiation light of the light emitting element 140, that is, the light reflected in the first accommodating portion 121.

In the second light receiving step, the second light receiving element 152 receives the P wave component of the reflected light (second reflected light) from the object to be measured with respect to the irradiation light of the light emitting element 140, while in the third light receiving step, the third light receiving step The light receiving element 153 receives the S wave component of the second reflected light.

In the basis weight measurement step, as shown in the above equation (1), the control circuit 200 causes the P wave component V (P) and the S wave component V (S) of the first reflected light V (R) to the second reflected light. ) Is subtracted to calculate the pseudo-transmitted light Vt', and the basis weight of the object to be measured is measured based on the pseudo-transmitted light Vt'.

In the glossiness measurement step, for example, based on the measurement results of the second light receiving element 152 and the third light receiving element 153 by the control circuit 200, for example, the specularly reflected light (P wave component in this embodiment) of the second reflected light. The glossiness of the object to be measured is measured based on the amount of light.

In the light emission control step, the control circuit 200 feedback-controls the light emitting element 140 so that the amount of irradiation light of the light emitting element 140 becomes constant based on the measurement result of the first light receiving element.

After all, in the basis weight measuring device 1 and the basis weight measuring method according to the present embodiment, the P wave component V (P) and the S wave component V (S) of the second reflected light are subtracted from the first reflected light V (R). Since the basis weight of the object to be measured is measured based on the pseudo transmitted light Vt'calculated as a result, a transmission type sensor unit and a receiver for receiving internally diffused reflected light are not required.

Therefore, according to the basis weight measuring device 1 and the basis weight measuring method according to the present embodiment, the basis weight of the object to be measured can be measured with a relatively simple configuration, and the size of the device is increased and the manufacturing cost is increased. It can be suppressed.

[Modification example]
Although the embodiment of the basis weight measuring device and the basis weight measuring method according to the present invention has been described above, the present invention is not limited to the above embodiment.

The basis weight measuring device according to the present invention includes a substrate, a lens holder arranged on the substrate, a lens arranged on the upper surface side of the lens holder, a light emitting element arranged on the substrate, and irradiation light of the light emitting element. A first light receiving element that receives the first reflected light from the lens holder, a second light receiving element that receives the P wave component of the second reflected light from the object to be measured with respect to the irradiation light, and an S wave of the second reflected light. The pseudo transmitted light of the object to be measured is calculated by subtracting the P wave component and the S wave component of the second reflected light from the third light receiving element that receives the components and the first reflected light, and the basis weight is calculated based on the pseudo transmitted light. If it is provided with a measuring unit for measuring, the configuration can be changed as appropriate.

For example, the control circuit 200 can provide at least a part of the functional units (for example, at least one of a basis weight measuring unit, a glossiness measuring unit, and a light emitting control unit) in the reflection type sensor 100.

The basis weight measuring method according to the present invention includes an irradiation step of irradiating an object to be measured with the irradiation light of the light emitting element of the reflective sensor, and a first reflected light from the lens holder with respect to the irradiation light by the first light receiving element of the reflective sensor. The first light receiving step for measuring the measurement, the second light receiving step for measuring the P wave component of the second reflected light from the object to be measured with respect to the irradiation light by the second light receiving element of the reflective sensor, and the third light receiving step of the reflective sensor. The third light receiving step for measuring the S wave component of the second reflected light by the element, and the pseudo transmitted light of the object to be measured are calculated by subtracting the P wave component and the S wave component of the second reflected light from the first reflected light. If it includes a basis weight measurement step of measuring basis weight based on pseudo transmitted light, the configuration can be appropriately changed.

1 Basis weight measuring device 100 Reflective sensor 110 Substrate 120 Lens holder 121 1st accommodating portion 122 2nd accommodating portion 123 3rd accommodating portion 124 Lens fixing portion 125 1st opening 126 2nd opening 127 Light shielding portion 130 Lens 131 Convex lens Part 132 Light-emitting lens part 133 Light-receiving lens part 140 Light-emitting element 151 First light-receiving element 152 Second light-receiving element 153 Third light-receiving element 160 Signal processing circuit 171 First polarization filter 172 Second polarization filter 200 Control circuit

In order to solve the above problems, the basis weight measuring device according to the present invention is
A basis weight measuring device that measures the basis weight of an object to be measured.
The object to be measured is printing paper.
With the board
A lens holder arranged on the substrate and forming a first accommodation space and a second accommodation space separated from each other on the substrate.
The lens arranged on the upper surface side of the lens holder and
A light emitting element arranged on the substrate in the first accommodation space and
A first light receiving element, which is arranged on the substrate in the first accommodation space and receives the first reflected light from the lens holder with respect to the irradiation light of the light emitting element.
A second light receiving element arranged on the substrate of the second accommodating space and receiving a P wave component of the second reflected light from the measurement object with respect to the irradiation light, and a second light receiving element.
A third light receiving element arranged on the substrate in the second accommodating space and receiving an S wave component of the second reflected light, and a third light receiving element.
The amount of pseudo-transmitted light of the measurement object is calculated by subtracting the amount of light of the P-wave component and the amount of light of the S-wave component of the second reflected light from the amount of light of the first reflected light, and the amount of light of the pseudo-transmitted light. With a measuring unit that measures the basis weight based on
Equipped with a,
The measuring unit controls the light emitting element so that the amount of the irradiation light becomes constant.
The lens holder has a first opening located above the light emitting element, and the first opening functions as a diaphragm portion that limits the irradiation range of the light emitting element .

In the above basis weight measuring device
The measuring unit can be configured to control the light emitting element so that the light amount of the irradiation light becomes constant based on the light amount of the first reflected light received by the first light receiving element.

In order to solve the above problems, the basis weight measuring method according to the present invention is
It is a basis weight measuring method that measures the basis weight of the object to be measured using a reflective sensor.
The object to be measured is printing paper.
An irradiation step of irradiating the object to be measured with the irradiation light of the light emitting element of the reflection type sensor via a lens arranged on the upper surface side of the lens holder of the reflection type sensor.
A first light receiving step of measuring the first reflected light from the lens holder with respect to the irradiation light by the first light receiving element of the reflective sensor, and a first light receiving step.
A second light receiving step of measuring the P wave component of the second reflected light from the measurement object with respect to the irradiation light by the second light receiving element of the reflective sensor.
A third light receiving step for measuring the S wave component of the second reflected light by the third light receiving element of the reflective sensor, and a third light receiving step.
The amount of pseudo-transmitted light of the measurement object is calculated by subtracting the amount of light of the P-wave component and the amount of light of the S-wave component of the second reflected light from the amount of light of the first reflected light, and the amount of light of the pseudo-transmitted light. The basis weight measurement step for measuring the basis weight based on
A light emission control step that controls the light emitting element so that the amount of the irradiation light becomes constant, and
Only including,
The lens holder has a first opening located above the light emitting element, and the first opening functions as a diaphragm portion that limits the irradiation range of the light emitting element .

The above basis weight measurement method is
Wherein the light emission control step, based on the amount of the first light receiving element has received the first reflected light can be configured Let 's light amount of the illumination light that controls the light-emitting element to be constant.

Claims (6)

A basis weight measuring device that measures the basis weight of an object to be measured.
With the board
A lens holder arranged on the substrate and forming a first accommodation space and a second accommodation space separated from each other on the substrate.
The lens arranged on the upper surface side of the lens holder and
A light emitting element arranged on the substrate in the first accommodation space and
A first light receiving element, which is arranged on the substrate in the first accommodation space and receives the first reflected light from the lens holder with respect to the irradiation light of the light emitting element.
A second light receiving element arranged on the substrate of the second accommodating space and receiving a P wave component of the second reflected light from the measurement object with respect to the irradiation light, and a second light receiving element.
A third light receiving element arranged on the substrate in the second accommodating space and receiving an S wave component of the second reflected light, and a third light receiving element.
A measurement in which the P-wave component and the S-wave component of the second reflected light are subtracted from the first reflected light to calculate the pseudo-transmitted light of the measurement object, and the basis weight is measured based on the pseudo-transmitted light. Department and
A basis weight measuring device characterized by being equipped with. The basis weight measuring device according to claim 1, wherein the measuring unit controls the light emitting element so that the amount of irradiation light becomes constant based on the measurement result of the first light receiving element. The basis weight measuring device according to claim 1 or 2, wherein the measuring unit measures the glossiness of the object to be measured based on the measurement results of the second light receiving element and the third light receiving element. .. It is a basis weight measuring method that measures the basis weight of the object to be measured using a reflective sensor.
An irradiation step of irradiating the object to be measured with the irradiation light of the light emitting element of the reflection type sensor via a lens arranged on the upper surface side of the lens holder of the reflection type sensor.
A first light receiving step of measuring the first reflected light from the lens holder with respect to the irradiation light by the first light receiving element of the reflective sensor, and a first light receiving step.
A second light receiving step of measuring the P wave component of the second reflected light from the measurement object with respect to the irradiation light by the second light receiving element of the reflective sensor.
A third light receiving step for measuring the S wave component of the second reflected light by the third light receiving element of the reflective sensor, and a third light receiving step.
Pseudo-transmitted light of the object to be measured is calculated by subtracting the P-wave component and the S-wave component of the second reflected light from the first reflected light, and the basis weight is measured based on the pseudo-transmitted light. With the quantity measurement step,
A method for measuring basis weight, which comprises. The method for measuring basis weight according to claim 4, further comprising a light emission control step of controlling the light emitting element so that the amount of irradiation light becomes constant based on the measurement result of the first light receiving element. The basis weight measurement according to claim 4 or 5, further comprising a glossiness measurement step of measuring the glossiness of the object to be measured based on the measurement results of the second light receiving element and the third light receiving element. Method.

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