JPH10206558A - Transmission type photoelectric sensor - Google Patents

Abstract

(57) [Problem] To provide a transmission type photoelectric sensor for detecting a detection object by transmitted light so that a mending tape stuck on paper can be accurately detected. SOLUTION: A PD1 is arranged on an optical axis of light emitted from an LED, a PD2 is arranged at a position other than the optical axis of light emitted from an LED, and a PD is arranged at a position other than on a line connecting PD1 and PD2.
By arranging D3, it is possible to capture the distribution shape of transmitted light having directivity preserved from paper or a thin sheet of a diffuse reflection system, and the distribution shape of transmitted light having lost directivity from a mending tape. Therefore, the mending tape can be accurately detected by comparing the two distribution shapes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric sensor for detecting a transparent pressure-sensitive adhesive tape whose surface is roughened so as to be hardly visually recognized on paper or a diffuse reflection type object.

[0002]

2. Description of the Related Art FIGS. 13 and 14 show a configuration of a conventional photoelectric sensor for optically detecting the surface state and the like of an object. FIG.
The photoelectric sensor 100 shown in FIG. 3A detects the collimated light 103 from the LED 101 through the lens 102 and detects the object 1
04 (hereinafter referred to as a work), and the work 10
4 is received by the line sensor 105. The line sensor 105 sets the workpiece 1 at an angle substantially equal to the angle at which the LED 101 enters the workpiece 104.
It is arranged at a position for receiving the reflected light emitted from the light-receiving element 04. FIG. 13B is a diagram illustrating a light reception distribution of the reflected light captured by the line sensor 105.
In the case of 00, discrimination of a work and detection of a surface state are performed by measuring a maximum value of a slope of a received light amount distribution of reflected light (hereinafter, referred to as a spire degree).

The photoelectric sensor 110 shown in FIG.
Light emitted from a light source 101 such as an LED is polarized by a polarizing filter 111 and irradiated on a work 104, and reflected light from the work 104 is polarized by a polarizing beam splitter 112.
(Hereinafter referred to as PBS), the light is separated into light in two polarization directions (the same polarization direction as the light polarized by the polarization filter 111 and a polarization direction orthogonal to the light), and the separated lights are respectively separated into the first light receiving element 113a and the first light receiving element 113a. Second light receiving element 113
The light is received at b. The PBS 112 moves the work 10 at an angle substantially equal to the incident angle from the LED 101 to the work 104.
4 is disposed at a position for receiving the reflected light emitted from the light-receiving element 4. The photoelectric sensor 110 includes two light receiving elements 113a, 113a.
13b captures light in two polarization directions included in the reflected light, and compares the amounts of light received by the two light receiving elements 113a and 113b to determine the work 104 and detect the surface state.

[0004]

However, FIG.
Is difficult to detect a transparent adhesive tape (hereinafter, referred to as a mending tape) which is difficult to visually recognize on paper. Less than,
The reason will be described with reference to FIGS. As shown in FIG.
Is roughened by scoring in one direction, and the cross section taken along line AA ′ in FIG.
(B). As described above, since the surface of the mending tape 120 has irregularities, as shown in FIG. 15C, when the surface of the mending tape 120 is irradiated with the collimated light 103 in a direction orthogonal to the streak direction, the irregularities on the surface are reduced. Changes the reflection direction, and the light reflected at a higher angle has a higher reflectance, so that the distribution of surface reflected light also changes. Therefore, when light is incident on the work 104 from the LED 101 at an incident angle of 55 °, the reflection characteristic on the surface of the mending tape 120 is such that the incident angle and the emission angle are not equal, as shown in FIG. , A peak of specular reflection light is generated.

FIG. 16 is a diagram showing the distribution of reflected light from paper and a mending tape adhered to the paper when light is irradiated at an incident angle of θ ゜. As can be seen from FIG.
In both the paper and the mending tape, the steepness (region where the gradient is maximum: 130 in FIG. 16) is located before the peak of the specular reflection light reception amount, and the gradients are almost the same in the region 130. Therefore, it is determined that the spire degrees of both works are the same. For this reason, it is difficult for the optical sensor device 100 shown in FIG. 13 that determines the work based on the sharpness to detect the mending tape stuck on the paper.

[0006] Even with the photoelectric sensor 110 as shown in Fig. 14 described above, it is difficult to detect a mending tape stuck on paper. The reason will be described with reference to FIG. FIG. 17 is a diagram showing a regular reflection light distribution of the paper and the mending tape when light is made to enter the paper and the mending tape from the LED 101 at an incident angle of 55 ° in the optical system having the configuration shown in FIG. . As shown in the figure, at the position of the emission angle equal to the incident angle (55 °), the regular reflection light amounts of the paper and the mending tape are substantially equal, and the polarization components are also substantially equal. Therefore, the output ratio of the first light receiving element 113a and the second light receiving element 113b does not change depending on the presence or absence of the mending tape, and it is difficult to detect the mending tape stuck on the paper.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended that light transmitted by paper or a sheet of a diffuse reflection system has directivity, and that the present invention is applied to a sheet of paper or a diffuse reflection system. Provided is a transmission type photoelectric sensor capable of accurately detecting a mending tape stuck on paper or a sheet by utilizing the fact that the directivity of transmitted light is lost due to roughening of the mending tape. The purpose is to do.

[0008]

According to a first aspect of the present invention, there is provided a light emitting unit including a light source including a light source and a light receiving unit including at least three light receiving elements. This is a mending tape on a thin sheet with a diffuse reflection system, and has a configuration in which a detection object passes between the light emitting unit and the light receiving unit, and receives the light transmitted from the light emitting unit through the paper or sheet. In a transmission-type photoelectric sensor that detects the presence or absence of a mending tape stuck on paper or a sheet by receiving light at a portion, a first light receiving element disposed on an optical axis of light emitted from a light source, And a third light receiving element disposed at a position other than on a line connecting the first and second light receiving elements. .

In this configuration, when light having high directivity is applied to paper or a thin sheet of a diffuse reflection system (hereinafter, referred to as paper), the transmitted light retains the directivity at the time of light projection to some extent. Therefore, the amount of light received by the first light receiving element is larger than the amounts of light received by the second and third light receiving elements. On the other hand, if paper is affixed to the mending tape, the mending tape has the property of losing directivity of transmitted light due to surface roughening, so the transmitted light approaches Lambertian distribution, The difference between the amount of light received by the first light receiving element and the amount of light received by the second and third light receiving elements is reduced. As described above, since the first to third light receiving elements can detect a large change in the distribution of transmitted light depending on the presence or absence of the mending tape, the mending tape can be detected. Further, since the distribution shape of the transmitted light is captured by the plurality of light receiving elements, malfunctions due to the color pattern of the paper can be reduced, and detection can be performed regardless of the direction in which the mending tape is stuck. Also,
Since the traveling direction of the transmitted light is hardly affected by the inclination of the paper, it is possible to detect the mending tape without changing the arrangement of the light receiving elements even when the paper is inclined.

According to a second aspect of the present invention, there is provided a light emitting unit including a light source, and a light receiving unit including at least three light receiving elements, wherein a detection object is formed by a mending tape on paper or a thin sheet of a diffuse reflection system. There is a configuration in which a detection object passes between the light emitting unit and the light receiving unit, and the light emitted from the light emitting unit is transmitted through the paper or sheet and received by the light receiving unit. In a transmission type photoelectric sensor for detecting the presence or absence of an affixed mending tape, a first light emitting unit including a first light source and a first light receiving unit including first to third three light receiving elements are provided. A first light emitting / receiving unit provided, a second light emitting unit disposed at a position facing the first light emitting / receiving unit with a sheet of paper or a diffuse reflection system therebetween, and including a second light source; And a second light receiving section including the sixth to sixth light receiving elements. A first light receiving element in the first light emitting and receiving unit is arranged on a light emitting optical axis of a second light source, and the second light receiving element is a second light emitting element. The third light receiving element is arranged at a position other than on a line connecting the first and second light receiving elements, and the second light emitting and receiving unit is arranged at a position other than on the light emitting optical axis of the light source. , The fourth light receiving element is disposed on the light projection optical axis of the first light source, the fifth light receiving element is disposed at a position other than on the light projection optical axis of the first light source, The sixth light receiving element is arranged at a position other than on a line connecting the fourth and fifth light receiving elements.

[0011] In this configuration, the first and second sheets are formed on paper or a thin sheet of a diffuse reflection system (hereinafter referred to as paper).
When light is emitted from a light source, the transmitted light has directivity at the time of light emission, so that the amount of light received by the first and fourth light receiving elements is smaller than the amount of light received by the other light receiving elements. It will be big. On the other hand, if paper is affixed to the mending tape, the mending tape has the property of losing directivity of transmitted light due to surface roughening, so the transmitted light approaches Lambertian distribution, The difference between the light receiving amounts of the first to third light receiving elements and the light receiving amounts of the fourth to sixth light receiving elements is reduced. As described above, since the first to sixth light receiving elements can detect a large change in the distribution shape of the transmitted light depending on the presence or absence of the mending tape, the mending tape can be detected. In addition, since light is emitted from both sides of the detection object, detection can be performed regardless of whether the mending tape is attached to the front or back surface of paper or the like.
Further, similarly to the transmission type photoelectric sensor of the first aspect, since the distribution shape of the transmitted light is detected by the plurality of light receiving elements, malfunction due to the color pattern of the paper can be reduced, and the mending tape can be applied in any direction. Detection can be performed. Furthermore, since detection is performed by transmitted light,
Detection can be performed even if the angle of the detection object with respect to the projection direction changes.

According to a third aspect of the present invention, in the configuration of the second aspect, when the first light receiving element in the first light emitting and receiving unit assumes that the surface of a sheet of paper or a diffuse reflection system is a mirror surface, The fourth light receiving element in the second light emitting and receiving unit is disposed at a position for receiving the light reflected by the mirror surface of the light emitted from the first light source. Assuming that the mirror is a mirror surface, it is arranged at a position for receiving light reflected from the mirror surface of light emitted from the second light source.

In general, a transparent tape has a high gloss and a large amount of specular reflection, and the traveling direction of the reflected light is the same as the reflection direction when the transparent tape is assumed to be a mirror surface. Claim 3
In the configuration of the above, the first and fourth light receiving elements are arranged at positions respectively receiving the light reflected by the mirrors of the light projected from the first and second light sources when the surface of paper or the like is assumed to be a mirror surface. Therefore, a large change in the amount of reflected light due to the presence or absence of the transparent tape can be detected, and not only the mending tape but also the transparent tape can be detected.

According to a fourth aspect of the present invention, in the configuration of any one of the first to third aspects, the first and second light receiving portions are constituted by a photodiode array or the like in which a plurality of light receiving elements are arranged. Is what it is.

In this configuration, since the distribution of the amount of received light can be more finely grasped, it is possible to detect the mending tape or the like more accurately.

According to a fifth aspect of the present invention, there is provided a photoelectric sensor according to any one of the first to fourth aspects, a paper feed mechanism for feeding paper, and a paper feed mechanism based on an output of the photoelectric sensor. And a control unit for controlling the operation.

In this configuration, the mending tape on the paper is detected by the photoelectric sensor according to any one of claims 1 to 4, and when the mending tape is detected, the control unit stops the paper feeding mechanism or stops the paper feeding mechanism. Reverse feed. Generally, when paper with a mending tape is put into a copying machine, the heat generated by the copying machine may melt the mending tape and cause a paper jam. In the configuration of the fifth aspect, since the mending tape can be accurately detected by the photoelectric sensor, the occurrence of paper jam due to the melting of the mending tape can be suppressed.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1A is a configuration diagram of a transmission type photoelectric sensor for detecting a mending tape according to the present embodiment, and FIG. 1B is a light receiving section constituting the transmission type photoelectric sensor. FIG. 3 is a top view (corresponding to claim 1). The transmission type photoelectric sensor 1 includes a light emitting diode (hereinafter, LE) as a light source.
D) (a first light source) and a light projecting unit 4 including a condenser lens 3 irradiate a highly directional light (collimated light) toward a detection object 5 (hereinafter, referred to as a work). The transmitted light is divided into three photodiodes (hereinafter, referred to as PDs) PD1, PD2, PD3 (first
Through the third light receiving element). In the light receiving section 6, the PD1 is arranged on the optical axis of light emitted from the LED, the PD2 is arranged at a position other than the optical axis of light emitted from the LED, and the PD3 is
It is arranged at a position other than on a straight line connecting PD1 and PD2. Based on the change in the amount of light received by these three PD1, PD2, and PD3, the mending tape attached to the paper is detected.

When light is applied to paper or a sheet of a diffuse reflection system (hereinafter, referred to as paper), light is transmitted when the thickness of the light is reduced to some extent. FIG. 2 (a)
Shows the distribution of transmitted light when the paper 10 is irradiated with collimated light having high directivity. As shown in the figure, the transmitted light approaches the Lambert distribution, but when the light is projected to some extent. Directional. On the other hand, when the mending tape 11 is affixed to the light receiving unit 6 side, the distribution state of the transmitted light becomes a Lambert distribution as shown in FIG. 2B, and the directivity at the time of light projection is lost. This is because, when the light transmitted through the paper 10 passes through the mending tape 11, the light is refracted by a roughening line applied to the surface of the tape 11. As described above, the distribution shape of the transmitted light changes depending on the presence or absence of the mending tape 11, and the light receiving amount ratio at the positions A and B in FIGS. 2A and 2B greatly changes.
The mending tape can be detected by arranging the PD 1 and the PD 2 and detecting the change in the amount of received light. Further, in the light receiving section 6, since the PD 3 is arranged at a position other than on a straight line connecting the PD 1 and the PD 2, a change in the amount of received light due to the presence or absence of the tape 11 can be captured regardless of the streak direction of the mending tape 11. Therefore, even if the tape 11 is stuck in any direction, the detection can be performed stably. Further, since the distribution shape of the transmitted light is captured by the three PDs, it is possible to reduce malfunction due to a color pattern such as paper.

Further, the transmission type photoelectric sensor 1 according to the present invention.
Is less affected by the inclination of the work 5 as compared with the conventional reflection type photoelectric sensor shown in FIGS. Hereinafter, the reason will be described with reference to FIGS. FIG.
FIG. 3A is a diagram showing a state of light reflected by the work 5 of light emitted from the LED when the work 5 is not tilted in the reflection type photoelectric sensor, and FIG. 3B is a view in which the work 5 is tilted. FIG. 7 is a diagram illustrating a state of light reflected by a work 5 of light emitted from an LED in a case. FIG. 4A is a view showing a state of light transmitted from the LED 5 when the work 5 is not tilted and transmitted by the work 5 in the transmission type photoelectric sensor, and FIG. 4B is a view showing the work 5 tilted. FIG. 6 is a diagram illustrating a state of light transmitted from a work 5 of light emitted from an LED when the LED is turned on. In the reflection-type photoelectric sensor, when the work 5 is tilted, the reflection direction of the reflected light shifts.
It is difficult for the PD arranged at the position of the reflection angle to receive the reflected light.
It is difficult to determine the change in the light reception amount of D and the change in the light reception amount of the PD due to the inclination of the work 5, and it is difficult to accurately detect the tape. On the other hand, in the transmission type photoelectric sensor, as shown in FIG. 4B, even if the work 5 is tilted, the traveling direction of the transmitted light does not change, and the PD arranged on the light projection optical axis.
Thus, a change in transmitted light due to the presence or absence of the mending tape can be detected, so that the mending tape can be accurately detected without being affected by the inclination of the work 5.

Next, the photoelectric sensor 1 according to the first embodiment
5 is shown in FIG. The light emitting pulse generating circuit 21 receiving the oscillation output from the oscillation circuit 20 generates a light emitting pulse signal and drives the LED. As a result, the LED emits light in a pulsed manner, and the light transmitted through the work out of the light is transmitted to the PD.
1, PD2 and PD3 receive light and convert it into an electric signal. Light receiving signals of PD1 and PD2, and PD1 and PD3
Are transmitted to the arithmetic circuit 23 via the peak hold circuit 22 (hereinafter, referred to as P / H circuit), and are calculated (division or subtraction). The calculated value is sent to a discrimination circuit 24 and compared with a threshold value 25.
Is output through As described above, the amount of light received by the PD 1 arranged on the light projecting optical axis and the PD arranged at a position other than the optical axis are different.
2. By comparing the amount of light received by the PD 3, the change in the distribution of transmitted light due to the presence or absence of the mending tape can be detected, so that the presence or absence of the mending tape can be accurately detected.

(Second Embodiment) FIG. 6A is a configuration diagram of a transmission type photoelectric sensor according to this embodiment, and FIG. 6B is a lower surface of a first light emitting / receiving unit constituting the transmission type photoelectric sensor. FIG. 6C is a top view of the second light emitting and receiving unit (corresponding to claim 2). This transmission type photoelectric sensor 30 has L
ED1 (first light source) and LED2 (second light source) emit light in a time-division manner and work 5 at each timing.
This device detects the presence or absence of a mending tape stuck on paper from the distribution shape of transmitted light. In FIG. 1A, the photoelectric sensor 30 includes a first light emitting / receiving unit 32a and a second light emitting / receiving unit 32b, and these units 32a and 32b face each other with the work 5 interposed therebetween. Are arranged as follows. The first light emitting and receiving unit 32a includes an LED 1, a first condenser lens 33a, and three PD1, PD2, and PD3 (first to third light receiving elements).
And the second light emitting and receiving unit 32b includes an LED.
The second and second condenser lenses 33b and three PD4, PD5,
PD6 (fourth to sixth light receiving elements) is provided. First
PD1 is the LED2
, The PD2 is disposed at a position other than on the projection optical axis of the LED2, and the PD3 is disposed on the P2
It is arranged at a position other than on a straight line connecting D1 and PD2. In the second light emitting / receiving unit 32b, the PD
4 is disposed on the light emitting optical axis of the LED 1, and PD5
Are arranged at positions other than on the light projecting optical axis of the LED 1, and the PD 6 is arranged at a position other than on a straight line connecting the PD 4 and the PD 5.

When light is applied to paper or a thin sheet of a diffuse reflection system, the transmitted light has directivity at the time of light projection. Therefore, the amount of light received by PD1 is smaller than the amount of light received by PD2 and PD3. And the amount of light received by PD4 is PD
5, which is larger than the amount of light received by the PD 6. On the other hand, if the mending tape is stuck on paper,
Since the transmitted light from the tape is diffused and has a Lambert distribution, the difference between the light reception amount of PD1 and the light reception amounts of PD2 and PD3 is small, and the light reception amount of PD4 is different from PD5 and PD.
The difference from the light receiving amount of No. 6 is small. As described above, the amount of light received by PD1 to PD6 changes depending on the presence or absence of the mending tape.
D2 / PD1, PD3 / PD1, PD5 / PD4, PD
By calculating the ratio of the amount of light received between the PD on the light projecting axis and the PD at other positions by a calculation such as 6 / PD4, a large change in the distribution shape of the transmitted light can be captured, and the accurate shape of the mending tape can be obtained. Detection can be performed. Further, since the light is projected from both sides of the work 5, accurate detection can be performed even when the mending tape is attached to either the front or back of the paper. Further, since the distribution shape of the transmitted light is captured by the plurality of PDs, malfunctions due to the color and pattern of the paper can be reduced, and stable detection can be performed even if the tape 11 is stuck in any direction. Further, since the photoelectric sensor 30 is of a transmission type,
Even if the work 5 is inclined, the detection can be performed accurately without being affected.

FIG. 7 shows a processing circuit of the photoelectric sensor 30 according to the second embodiment. The LEDs 1 and 2 are driven in a time-division manner on the basis of the light emission pulse signal from the pulse generation circuit 21.
H circuit 22 is driven in synchronization with LED1, and PD
1, a P / H circuit 22 corresponding to PD2 is driven in synchronization with LED2. The values detected by the respective P / H circuits 22 are sent to operation circuits 23, respectively, and are subjected to division or subtraction operations to obtain PDs arranged on the light projecting optical axis.
1, the amount of light received by PD4 and P
The light receiving amounts of D2, PD3, PD5, and PD6 are compared. The operation values from these operation circuits 23 are
Is compared with the threshold value 25 and output from the OR circuit 26.

(Third Embodiment) FIG. 8A is a configuration diagram of a transmission type photoelectric sensor according to this embodiment, and FIG. 8B is a lower surface of a first light emitting / receiving unit constituting the transmission type photoelectric sensor. FIG. 8C is a top view of the second light emitting and receiving unit (corresponding to claim 3). This photoelectric sensor 40 is an LED
This device detects the presence or absence of a mending tape and a transparent tape stuck on paper by projecting light from the LED 2 in a time-division manner and capturing transmitted light and reflected light from the work 5 at each timing. In FIG. 1A, a photoelectric sensor 40 is composed of a first light emitting and receiving unit 32a and a second light emitting and receiving unit 32b, and these units 32 and 32b face each other with the work 5 interposed therebetween. Are arranged as follows. The first light emitting and receiving unit 32a includes an LED1 and three PD1, PD2, and PD3, and the second light emitting and receiving unit 32b includes an LED2.
And three PD4, PD5, and PD6.

P on the first light emitting / receiving unit 32a
D1 is arranged on the projection optical axis of LED2, and PD
2 is arranged at a position other than on the light projection optical axis of LED2, and PD3 is arranged at a position other than on a straight line connecting PD1 and PD2. Also, the second light emitting / receiving unit 32b
, The PD4 is arranged on the light-projecting optical axis of the LED1, the PD5 is arranged at a position other than on the light-projecting optical axis of the LED1, and the PD6 is arranged at a position other than on a straight line connecting the PD4 and the PD5. Are located. Further, when assuming that the surface of the work 5 is a mirror surface, the PD 1 receives reflected light of the light projected from the LED 1 on the mirror surface, and the PD 4 receives the light reflected by the work surface.
Assuming that the surface is a mirror surface, it is arranged at a position where the light emitted from the LED 2 is reflected by the mirror surface. Note that the incident angles of the LED 1 and the LED 2 with respect to the work 5 are equal.

In general, a transparent tape has a high gloss and a large amount of specular reflection. The traveling direction of the reflected light is the same as the reflection direction when the transparent tape is assumed to have a mirror surface.
In the photoelectric sensor 40 according to the present embodiment, the work 5
Is a transparent tape affixed on paper, the PD1 can receive the regular reflection light of the light emitted from the LED1 by the transparent tape. Similarly, regular reflection light of the light projected from the LED 2 by the transparent tape can be received by the PD 4. As described above, since the increase and decrease of the specular reflection light due to the presence or absence of the transparent tape can be detected by PD1 and PD4, it is possible to accurately detect the transparent tape. Further, similarly to the transmission type photoelectric sensor 30 shown in the above-described second embodiment, PD4, PD5, and PD6 receive the transmitted light of the light emitted from the LED 1 by the work 5, and the work of the light emitted from the LED2. By detecting the transmitted light by PD1, PD2, and PD3, the distribution shape of the transmitted light is detected, so that the presence or absence of the mending tape can be detected at the same time.

FIG. 9 shows a photoelectric sensor 4 according to the third embodiment.
0 is a processing circuit diagram of FIG. PD1 and PD4 are 2
Connected to one P / H circuit 22. When LED1 is driven, the S / H circuit 22 connected to PD4, PD5, PD6, and PD1 is driven in synchronization with this. On the other hand, when LED2 is driven, PD1,
S / H circuit 22 connected to PD2, PD3 and PD4
Is driven. Thus, not only the transmitted light from the work 5 but also the reflected light can be captured, so that not only the mending tape but also the transparent tape can be detected.

(Fourth Embodiment) FIG. 10A is a structural view of a transmission type photoelectric sensor 50 according to the present embodiment, and FIG.
10B is a bottom view of a first light emitting and receiving unit constituting the transmission type photoelectric sensor, and FIG. 10C is a top view of a second light emitting and receiving unit (corresponding to claim 4). This transmission type photoelectric sensor 50 is the transmission type photoelectric sensor 30 shown in FIG.
In the above, the light receiving portion composed of PD1 to PD6 is constituted by a two-divided PD51. As a result, compared to the transmission type photoelectric sensor 30 shown in FIG. 6, transmitted light is captured at multiple points, so that the distribution shape of transmitted light can be captured more finely, and the performance of the sensor can be improved. Note that a PD array, CC,
D, a configuration including a line sensor and the like may be adopted. In this case, the distribution shape of the transmitted light can be grasped, so that the performance of the photoelectric sensor can be improved. Further, in the present embodiment, the photoelectric sensor 30 shown in FIG. 6 is replaced with the two-part PD 51 in the light receiving section, but the photoelectric sensor 1 in FIG. 1 and the photoelectric sensor 40 in FIG. May be replaced with a two-divided PD 51 or the like. In this case, the performance of each photoelectric sensor can be improved.

(Fifth Embodiment) FIG. 11 is a block diagram showing a copying apparatus provided with a photoelectric sensor according to the present embodiment (corresponding to claim 5). The copying apparatus 60 includes a tray 61
The photoelectric sensor 63 detects a mending tape affixed on the paper 62 disposed therein, and when the mending tape is detected, the paper feeding mechanism 64 is stopped or reversed. Generally, when the paper 62 on which the mending tape is adhered is put into a copying apparatus, the heat generated by the copying apparatus may melt the mending tape and cause a paper jam. The photoelectric sensor 63 includes the above-described first to fourth elements.
Since the mending tape can be accurately detected, it is possible to suppress the occurrence of a paper jam due to the melting of the mending tape.

(Sixth Embodiment) FIG. 12 is a view showing a configuration of a bill discriminating apparatus according to the present embodiment. The bill discriminating device 70 includes a mending tape 72 affixed on a bill 71.
Is detected by the photoelectric sensor 63, and the one to which the tape 72 is attached is determined to be a falsified banknote. Since the bill 71 is slightly glossy and its reflection characteristics are similar to those of the mending tape 72, it is difficult to detect the mending tape 72 on the bill 71 with a conventional photoelectric sensor. However, in the photoelectric sensor 63 of the present invention, since the detection is performed by capturing the transmitted light from the mending tape 72, the presence / absence of the mending tape 72 on the banknote 71 can be accurately detected, and more reliably. It can be determined whether or not the banknote is a falsified banknote.

[0032]

As described above, according to the transmission type photoelectric sensor according to the first aspect, the first light receiving element is disposed on the optical axis of the light emitted from the light source, and the first light receiving element is disposed on the optical axis other than the optical axis of the light emitted from the light source. In the second position
By arranging the third light receiving element at a position other than the line connecting the first and second light receiving elements, the directivity from paper or a thin sheet of a diffuse reflection system can be preserved. Since the distribution shape of the transmitted light and the distribution shape of the transmitted light having lost directivity from the mending tape can be grasped, the mending tape can be accurately detected by comparing the two distribution shapes. In addition, since this transmission type photoelectric sensor performs detection using transmitted light, detection can be accurately performed even when the angle of paper or mending tape changes. Furthermore, since the distribution shape of the transmitted light is captured by the plurality of light receiving elements, malfunctions due to the color pattern of the paper can be reduced, and accurate detection can be performed regardless of the direction in which the mending tape is stuck.

Further, according to the transmission type photoelectric sensor of the present invention, the first and second two light emitting and receiving units each having one light source and three light receiving elements are provided on both sides of the detection object. And the transmitted light from the detection object of the light emitted from the light source of the first light emitting and receiving unit is received by the three light receiving elements of the second light emitting and receiving unit, and is projected from the light source of the second light emitting and receiving unit. In addition to the effect of the transmission type photoelectric sensor according to the first aspect, the configuration is such that the transmitted light from the detection object of the emitted light is received by the three light receiving elements of the first light emitting and receiving unit. It is possible to perform accurate detection even when the ding tape is stuck on both the front and back surfaces of the paper.

According to the transmission type photoelectric sensor of the third aspect, in the configuration of the second aspect, it is assumed that one light receiving element of the light emitting / receiving unit is a paper or a surface of a diffuse reflection type sheet is a mirror surface. By arranging it at the position where the light reflected from the mirror surface of the light projected from the light source is received, the peak of the specular reflection light from the transparent tape can be captured. Can be accurately detected.

According to the transmission type photoelectric sensor of the fourth aspect, in any one of the configurations of the first to third aspects, the light receiving portion is constituted by a photodiode array or the like in which a plurality of light receiving elements are arranged. This makes it possible to more finely grasp the distribution of the amount of received light, so that the mending tape can be detected more accurately.

According to the copying apparatus of the fifth aspect, the transmission type photoelectric sensor of any one of the first to fourth aspects is provided to enable accurate detection of the mending tape. Therefore, the paper to which the mending tape is stuck can be eliminated, so that paper jam which can occur when the tape is melted by the heat generated by the copying apparatus and can occur can be prevented.

[Brief description of the drawings]

FIG. 1A is a configuration diagram of a transmission type photoelectric sensor according to a first embodiment, and FIG. 1B is a top view of a light receiving unit of the sensor.

FIG. 2A is a diagram illustrating a distribution shape of transmitted light by paper;
(B) is a figure which shows the distribution shape of the transmitted light by the mending tape stuck on paper.

3A is a diagram illustrating a state of incident light and reflected light with respect to the work when the work is not inclined, and FIG. 3B is a diagram illustrating a state of incident light and reflected light with respect to the work when the work is inclined. FIG.

4A is a diagram showing a state of incident light and transmitted light with respect to a work when the work is not inclined, and FIG. 4B is a view showing a state of incident light and transmitted light with respect to the work when the work is inclined. FIG.

FIG. 5 is a processing circuit diagram of the transmission type photoelectric sensor according to the first embodiment.

6A is a configuration diagram of a transmission type photoelectric sensor according to a second embodiment, FIG. 6B is a bottom view of a first light emitting / receiving unit of the sensor, and FIG. 6C is a second light emitting unit of the sensor. It is a top view of a light receiving unit.

FIG. 7 is a processing circuit diagram of a photoelectric sensor according to a second embodiment.

8A is a configuration diagram of a transmission type photoelectric sensor according to a third embodiment, FIG. 8B is a bottom view of a first light emitting and receiving unit of the sensor, and FIG. 8C is a second light emitting unit of the sensor. It is a top view of a light receiving unit.

FIG. 9 is a processing circuit diagram of a transmission type photoelectric sensor according to a third embodiment.

10A is a configuration diagram of a transmission type photoelectric sensor according to a fourth embodiment, FIG. 10B is a bottom view of a first light emitting / receiving unit of the sensor, and FIG. 10C is a second light emitting unit of the sensor. It is a top view of a light receiving unit.

FIG. 11 is a diagram illustrating a configuration of a copying apparatus according to a fifth embodiment.

FIG. 12 is a diagram illustrating a configuration of a bill discriminating apparatus according to a sixth embodiment.

13A is a configuration diagram of a conventional photoelectric sensor that optically detects a mending tape, and FIG. 13B is a diagram illustrating a light reception amount on a line sensor.

FIG. 14 is a configuration diagram of a conventional photoelectric sensor that optically detects a mending tape.

15A is a configuration diagram of a mending tape, FIG.
(B) is an enlarged cross-sectional view taken along the line AA 'of (a), (c) is a view showing a state of reflection on the surface when the mending tape is irradiated with collimated light, and (d) is an incident angle of incident light. FIG. 6 is a diagram showing reflection characteristics on the surface of the mending tape when the angle is set to 55 °.

FIG. 16 is a diagram showing a distribution of reflected light of paper and a mending tape stuck on the paper when light is irradiated with an incident angle θ ゜.

FIG. 17 is a diagram showing a regular reflection light distribution of the paper and the mending tape when light is incident from the light source toward the paper and the mending tape at an incident angle of 55 °.

[Explanation of symbols]

 Reference Signs List 1, 30, 40, 50 Photoelectric sensor 4 Light emitting unit 5 Workpiece (detected object) 6 Light receiving unit 10 Paper 11 Mending tape 32a First light emitting and receiving unit 32b Second light emitting and receiving unit 51 Photodiode array 60 Copy device 62 Paper 63 Photoelectric sensor 64 Paper feed mechanism 72 Mending tape LED light source LED1 First light source LED2 Second light source PD1 First light receiving element PD2 Second light receiving element PD3 Third light receiving element PD4 Fourth light receiving element PD5 5th light receiving element PD6 6th light receiving element

Claims (5)

[Claims] 1. A light-emitting unit including a light source and a light-receiving unit including at least three light-receiving elements, wherein a detection object is a mending tape on paper or a thin sheet of a diffuse reflection system,
The detecting object has a configuration in which the detection object passes between the light emitting unit and the light receiving unit, and the light receiving unit receives light transmitted from the light emitting unit through a paper or a sheet. In a transmission type photoelectric sensor for detecting the presence or absence of a mending tape stuck on a sheet, a first light receiving element arranged on an optical axis of light emitted from the light source, except for an optical axis of light emitted from the light source The second placed at the position of
And a third light-receiving element disposed at a position other than on a line connecting the first and second light-receiving elements. 2. A light-emitting unit including a light source, and a light-receiving unit including at least three light-receiving elements, wherein a detection object is a mending tape on paper or a thin sheet of a diffuse reflection system,
The detecting object has a configuration in which the detection object passes between the light emitting unit and the light receiving unit, and the light receiving unit receives light transmitted from the light emitting unit through a paper or a sheet. In a transmission type photoelectric sensor for detecting the presence or absence of a mending tape stuck on a sheet, a first light emitting unit including a first light source and a first light receiving unit including first to third three light receiving elements A light emitting and receiving unit including a second light source and a second light source, the second light emitting unit being disposed at a position facing the first light emitting and receiving unit with the paper or the diffuse reflection type sheet interposed therebetween. And a second light emitting and receiving unit including a second light receiving unit including fourth to sixth three light receiving elements, wherein the first light receiving element in the first light emitting and receiving unit is , Disposed on the projection optical axis of the second light source, The light receiving element is arranged at a position other than on the light projection optical axis of the second light source, and the third light receiving element is arranged at a position other than on a line connecting the first and second light receiving elements. The fourth light receiving element in the second light emitting and receiving unit is disposed on a light emitting optical axis of the first light source, and the fifth light receiving element is a light emitting element of the first light source. The transmission-type photoelectric conversion device is arranged at a position other than on the light projection optical axis, and the sixth light receiving element is arranged at a position other than on a line connecting the fourth and fifth light receiving elements. Sensor. 3. The first light emitting and receiving unit in the first light emitting and receiving unit.
The light-receiving element is disposed at a position for receiving light reflected from the mirror surface of light emitted from the first light source, assuming that the surface of the sheet of paper or a diffuse reflection system is a mirror surface, A fourth light receiving element in the second light emitting and receiving unit,
When the surface of the paper or the sheet of the diffuse reflection system is assumed to be a mirror surface, it is arranged at a position for receiving light reflected by the mirror surface of light projected from the second light source. Item 3. A transmission type photoelectric sensor according to item 2. 4. The device according to claim 1, wherein the first and second light receiving units are formed of a photodiode array in which a plurality of light receiving elements are arranged. Transmission type photoelectric sensor. 5. The transmission type photoelectric sensor according to claim 1, a paper feeding mechanism for feeding paper, and an operation of the paper feeding mechanism based on an output of the transmission type photoelectric sensor. And a control unit for controlling the copying.