JPH08327315A - Medium detector - Google Patents

Abstract

PURPOSE: To prevent a prism from being stained and influenced by a disturbance light, by setting a case to surround two reflecting faces of the prism being a reflecting body. CONSTITUTION: The light from a light-emitting element 7, passing through a hole 5 of a transfer guide 3 and a transfer path 2, enters a prism 10 from an entrance part 11 to reach a reflecting face 13. The light is reflected to be in the horizontal direction and reaches a reflecting face 14, where the light is reflected again to a photodetecting element 8. The light reflected at the reflecting face 14 is, coming out of the prism 10 through a projection part 12 and passing the transfer path 2, sent into the photodetecting element 8 after penetrating a hole 6 of the transfer guide 3. When a mediums is transferred and passes between the light-emitting element 7 or photodetecting element 8 and the prism 10, the amount of light at the light-emitting element 7 is attenuated and the amount of light detected by the photodetecting element 8 is changed. Since a case 17 is formed in the periphery of the prism 10, disturbance lights are hard to enter the reflecting faces 13, 14 of the prism 10. The change of the amount of light can thus be detected correctly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium detecting device for optically detecting a medium conveyed on a conveying path, and more particularly, a light emitting element for emitting light and a light receiving element for receiving light are provided on the same side of the conveying path. , A medium detection device in which a reflector that reflects light is on the opposite side of the transport path.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for optically detecting a carrier medium, a light emitting element and a light receiving element are arranged on both sides of a carrier path for transporting the medium, and light emitted from the light emitting element is guided through the carrier path. The light receiving element was used to receive the light. Then, when the medium is conveyed through the conveying path, the medium blocks the light emitted from the light emitting element, so that the light does not reach the light receiving element,
Thereby, the conveyance of the medium is detected. However, in such a detection device, for example, when detecting skew of the medium, it is necessary to detect the medium at two locations, and therefore two pairs of light emitting elements and light receiving elements must be provided. That is, the number of elements increases, and as the number increases, circuits and connecting cords become complicated. In order to deal with such a situation, a prism as a reflector is provided, and even when detecting skew, the light emitting element and the light receiving element are combined.
There are only pairs. (See JP-A-6-100205)

[0003]

However, in the above-mentioned conventional detecting device, since the prism for reflecting light is exposed, there is a problem that the prism becomes dirty when a finger or the like touches the prism during inspection of the device. there were. Further, since the prism is exposed, there is a problem that it is easily affected by ambient light.

[0004]

In order to solve the above-mentioned problems, the present invention has a light emitting element and a light receiving element on one side of a conveying path for conveying a medium, and a light emitting element and a light receiving element on the opposite side of the conveying path. A medium detecting device comprising a reflector having a first reflecting surface that reflects light and a second reflecting surface that reflects light from the first reflecting surface toward the light receiving element, It is characterized in that a surrounding member surrounding the first and second reflecting surfaces is provided.

Further, the surrounding member may be configured to block ambient light, and a cover member mounted on the surrounding member and covering at least the first and second reflecting surfaces of the reflector may be provided. May be.

[0006]

According to the present invention having the above-described structure, since the surrounding member is provided, the finger or the like does not come into contact during inspection, so that the reflector is not contaminated. Further, by making the surrounding member to block the ambient light, the influence of the ambient light can be prevented.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. Note that elements common to the drawings are given the same reference numerals. FIG. 1 is a perspective view showing a medium detecting device of a first embodiment according to the present invention, and FIG. 2 is a side sectional view showing the medium detecting device of the first embodiment. The first embodiment will be described with reference to both drawings.

In both figures, the transport path 2 for the transport medium 1 is formed by the upper and lower transport guides 3, 4. The upper and lower transport guides 3 and 4 are horizontally supported with a predetermined space. Circular holes 5 and 6 are formed in the upper conveyance guide 3, and the light emitting element 7 and the light receiving element 8 are inserted into the holes 5 and 6 from above. The light emitting element 7 is composed of a light emitting diode, the light receiving element 8 is composed of a phototransistor, and both are mounted on the printed board 9.

A prism 10 is attached to the lower transport guide 4. The prism 10 is made of a material having a high refractive index,
For example, it is made of glass or an optically transparent resin, and has a cylindrical projection-shaped light entrance portion 11 for entering the light emitted from the light emitting element 7, and a cylindrical shape for emitting light to the light receiving element 8. It has a light emitting portion 12 in the shape of a protrusion. Also prism 1
Reference numeral 0 has a first reflecting surface 13 that reflects light traveling straight from the light emitting element 7 in the horizontal direction and a second reflecting surface 14 that reflects light from the first reflecting surface 13 in the direction of the light receiving element 8. As shown in FIG. 2, the light entrance portion 11 and the light exit portion 12 are chamfered or R-finished, and the light entrance portion 11 and the light exit portion 12 have holes 15 in the lower conveyance guide 4, respectively.
The prism 10 is attached by being fitted in 16. As shown in FIG. 2, the light entrance part 11 and the light exit part 12 have holes 15,
16 does not project to the transport path 2.

The case 1 surrounds the prism 10.
7 is formed integrally with the prism 10. Case 17
2, the height L1 of the prism 10 is higher than the height L2 of the prism 10 so that ambient light is unlikely to enter the first and second reflecting surfaces 13 and 14 of the prism 10. Case 1
A protrusion 18 for attaching the case 17 to an attachment member (not shown) is formed on the outer side of 7.

In FIG. 2, a connector 19 is mounted on the printed board 9 and is connected to a drive circuit (not shown) via a cord 20.

Next, the operation of the first embodiment will be described. The light emitted from the light emitting element 7 passes through the hole 5 of the transport guide 3, passes through the transport path 2, enters the prism 10 from the light incident portion 11, and reaches the first reflecting surface 13. Here, the light is reflected in the horizontal direction, reaches the second reflecting surface 14, and is reflected again toward the light receiving element 8 here. The light reflected by the second reflecting surface 14 exits the prism 10 from the light emitting section 12, passes through the transport path 2, passes through the hole 6 of the transport guide 3, and enters the light receiving element 8. By carrying out such light emission and light reception, the transport state of the medium 1 on the transport path 2 is detected.

That is, the medium 1 is conveyed and the light emitting element 7
Or when passing between the light receiving element 8 and the prism 10,
As a result, the light amount of the light emitting element 7 is attenuated, and the light amount received by the light receiving element 8 changes. By measuring the change in the amount of light received by the light receiving element 8, the presence or absence of the medium 1 can be detected, and by measuring the change in the amount of received light over time, the medium 1
The position, size, transport speed, etc. of can be detected. At this time, since the case 17 is formed around the prism 10, the first and second reflecting surfaces 13 of the prism 10 are
It is difficult for ambient light to enter 14 and changes in the amount of light can be accurately detected.

In the above embodiment, the prism 10 and the case 1 are
Although 7 is formed integrally, it does not necessarily have to be integrated.
However, when the prism 10 and the case 17 are made of the same material, the cost will be lower if they are integrated. Further, when the case 17 is made of a colored material having a light shielding property, it is not always necessary to integrate the case.

As described above, according to the first embodiment, since the case 17 is provided around the prism 10, it is difficult for a finger or the like to come into contact with the prism reflection surfaces 13 and 14 at the time of assembling or inspecting, so that the prism is not contaminated. Is prevented. Further, since the height of the case 17 is made higher than that of the prism 10, the prism reflection surface 1 for the ambient light is
There is an effect that the influence on the mediums 3 and 14 is reduced and the medium is accurately detected. Further, the light entering portion 11 of the prism 10
Since the light emitting portion 12 has a cylindrical projection shape, the prism 10 can be easily positioned by fitting these into the holes of the transport guide. Since the light entrance portion 11 and the light exit portion 12 are inside the holes 15 and 16, the medium 1 does not come into contact with them, but even if they come into contact with each other, the tips of the light entrance portion 11 and the light exit portion 12 are Since it is chamfered or rounded, it does not affect the transport state of the medium.

Next, a second embodiment according to the present invention will be described.
FIG. 3 is a perspective view showing the prism case of the second embodiment, and FIG.
[FIG. 8] A sectional view showing a prism case of a second embodiment. In addition to the configuration of the first embodiment, the medium carrying device of the second embodiment has a prism case provided with a light-shielding cap.

In FIGS. 3 and 4, a cap 22 is fitted inside the case 17. Cap 22
Is formed in a box shape as a whole, and the protrusions 23a, 23
b is formed. The projections 23a and 23b are fitted into the holes 24a and 24b formed on both sides of the case 17, and the cap 22 is fixed. The cap 22 is molded from an inexpensive resin. Generally, inexpensive resin has a low light-shielding property, and therefore the prism 10 using the cap 22 made of such a resin should be mounted in a place that is not significantly affected by ambient light. The other structure is similar to that of the first embodiment.

In the second embodiment constructed as described above, since the cap 22 is provided, the prism 10 is covered with the cap 22 and dust or the like does not adhere to the prism 10. It is also resistant to aging.

As a modification of the second embodiment, the cap may be formed of a light-shielding member and the prism 10 as a whole may be shaped to cover the light entrance portion 11 and the light exit portion 12 as well. Further, as the material of the cap 22, it is sufficient to use a material having a light-shielding property, but since a resin that shields all wavelengths is generally expensive, a resin having a property of shielding at least light of a wavelength that can be received by the light-receiving element 8 is used. Good to use. The use of the light-shielding cap makes it less susceptible to the influence of ambient light, and makes the medium detection operation more accurate.

[0020]

As described above in detail, according to the present invention, the case is provided around the prism, so that the prism can be prevented from being contaminated and can be less affected by ambient light.

[Brief description of drawings]

FIG. 1 is a perspective view showing a medium detection device according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing the medium detection device of the first embodiment.

FIG. 3 is a perspective view showing a prism case of a second embodiment.

FIG. 4 is a sectional view showing a prism case of a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Medium 2 Transport path 7 Light emitting element 8 Light receiving element 10 Prism 13 First reflecting surface 14 Second reflecting surface 22 Cap

Claims (5)

[Claims] 1. A first reflecting surface having a light emitting element and a light receiving element on one side of a conveying path for conveying a medium, and a first reflecting surface for reflecting light from the light emitting element on the opposite side of the conveying path, and the first reflecting surface. In a medium detection device including a reflector having a second reflection surface that reflects light from a surface toward the light receiving element, a surrounding member that surrounds the first and second reflection surfaces of the reflector is provided. A medium detection device characterized by the above. 2. The medium detection device according to claim 1, wherein the surrounding member is integral with the reflector. 3. The medium detection device according to claim 1, wherein the surrounding member blocks ambient light. 4. The medium detection device according to claim 1, further comprising a cover member that is mounted on the surrounding member and covers at least the first and second reflecting surfaces of the reflector. 5. The medium detection device according to claim 4, wherein the cover member is made of a light shielding material.