JP2004075368A - Reflection type photo interrupter, paper feeding device equipped with this photo interrupter, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize space saving in the height direction of a device. <P>SOLUTION: A plurality of harnesses 12 for external connection connected with a light emitting element 3 and light receiving element 4 respectively are led out to the back surface side of a frame 5, respectively, in roughly parallel to a detection center line CL which passes through an intersection O of an optical axis 8 of the light emitting element 3 and an optical axis 9 of the light receiving element 4 and intersects perpendicularly to the surface of the frame 5, so as to form a reflection type photo interrupter 1. As a result, the reflection type photo interrupter 1 can be installed without need for much labor for harness routing by the insertion from condenser lens 6, 7 if there is a room for the external dimension of a case 2, thus enabling installation with much space saving. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reflection type photointerrupter for detecting the presence or absence of a detection target by receiving reflected light reflected by the detection target by a light receiving element by a light emitting element, a sheet feeder including the same, and an image forming apparatus. Equipment related.
[0002]
[Prior art]
Such a reflective photointerrupter is disclosed in, for example, JP-A-11-49405, as shown in FIG. The reflection type photo interrupter detects the presence or absence of the detection target 50 by receiving light reflected from the detection target 50 by irradiation from the light emitting element 51 by the light receiving element 52. Such a reflective photo-interrupter is a non-contact sensor capable of detecting various objects to be detected in a non-contact state, and is used for detecting a sheet in a sheet conveying system of an image forming apparatus such as a copying machine or a printer. Many are used.
In particular, in recent years, there has been a demand for a higher print speed in an image forming apparatus, and accordingly, there has been a tendency to narrow a conveyance interval between papers. In a transmission type photo-interrupter with an actuator (oscillating filler), the detection speed of a sheet cannot be made in time, so that the necessity of a reflection type photo-interrupter is increasing.
On the other hand, in such an image forming apparatus such as a copying machine and a printer, space saving of the apparatus has recently been required. On the other hand, the paper feeder that feeds the paper is required to have multiple paper feed trays and large capacity, so the height occupied by the vertical transport path of the paper feeder per paper feed port should be as low as possible. Is required.
[0003]
[Problems to be solved by the invention]
However, in such a vertical transport path, usually, it is necessary to provide a transport roller for transporting the paper upward and a photo interrupter for detecting the paper passing therethrough. Since the length of the device is easily increased, it is difficult to reduce the space in the height direction of the entire device.
Also, if the entire device body is made smaller by saving space, the space inside the device body will be reduced accordingly, so if a reflective photo interrupter is used for a vertical transport path, etc., the light emitting element of the reflective photo interrupter Unnecessary reflected light that is reflected when the irradiated light hits a wall or the like in the apparatus main body is easily detected by the light receiving element. In this case, the S / N ratio obtained depending on the presence / absence of the paper to be detected is reduced, so that even if the paper does not exist, the presence of the paper is erroneously detected by the reflected light from other than the paper (detected body). There was a risk of becoming like this.
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides a reflection-type photointerrupter capable of saving space in the height direction of the apparatus, a sheet feeder including the same, and an image forming apparatus. The purpose is to provide.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a light emitting element and a light receiving element are arranged in parallel with a frame in a state of being separated by a light shielding member, and a case is attached to the frame so as to accommodate the light emitting element and the light receiving element. In the reflection type photointerrupter, which is configured to detect the presence or absence of the detection target by receiving the reflected light reflected by the detection target irradiated from the light emitting element by the light receiving element,
An external connection harness connected to the light-emitting element and the light-receiving element, respectively, is substantially parallel to a detection center line that passes through the intersection of the optical axis of the light-emitting element and the optical axis of the light-receiving element and intersects perpendicularly with the plane of the frame. It was pulled out on the back side of the frame.
Further, a paper feed device comprising any one of the above-described reflective photo-interrupters, provided with a transport roller having a plurality of rollers fixed on a shaft at intervals in a vertical transport path for transporting the paper in a vertical direction,
The reflective photo-interrupter is arranged near the upper side of the shaft between the rollers of the transport roller so that the optical axis of the light emitted from the light-emitting element is directed downward from the horizontal, and is vertically arranged by the reflective photo-interrupter. Provided is a sheet feeding device capable of detecting a sheet conveyed on a conveying path.
Further, the present invention also provides an image forming apparatus provided with the above-mentioned paper feeding device.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a cross section of an embodiment of a reflection type photo interrupter according to the present invention, and FIG. 2 is a perspective view showing the appearance of the reflection type photo interrupter.
The reflective photo-interrupter 1 shown in FIG. 1 is a light-shielding member made of a light-shielding resin, and a light-emitting element 3 and a light-receiving element 4 are separated from each other by a light-shielding wall 2 a which is a part of a case 2. It is arranged in parallel on the surface. The case 2 is attached to the frame 5 by fitting the recesses 2b and 2c to accommodate the light emitting element 3 and the light receiving element 4.
A condensing lens 6 serving also as a resin cover made of a translucent material covering the front surfaces of the light emitting element 3 and the light receiving element 4 is provided on the front surface (right side in FIG. 1) of each of the light emitting element 3 and the light receiving element 4. , 7 are provided, and the condenser lenses 6, 7 are fixed to the case 2 by fitting or the like. The condensing lenses 6 and 7 are arranged so as to be inclined in a direction in which the optical axis 8 of the light emitting element 3 and the optical axis 9 of the light receiving element 4 cross each other on the front side.
[0006]
In the reflection type photointerrupter 1, an external connection connector 11 is attached to the back side of the frame 5, and a plurality of external connection harnesses 12 are drawn out of the external connection connector 11 respectively.
That is, the light-emitting element 3 and the light-receiving element 4 are connected to the light-emitting element 3 and the light-receiving element 4, respectively, substantially in parallel with the detection center line CL that passes through the intersection point O of the light-emitting element 3 and the optical axis 9 of the light-receiving element 4 and intersects perpendicularly with the surface of the frame 5. A plurality of external connection harnesses 12 are drawn out to the rear side of the frame 5 respectively.
The reflection type photointerrupter 1 detects the presence or absence of the detected object 15 by receiving the reflected light emitted from the light emitting element 3 and reflected by the detected object 15 by the light receiving element 4.
The case 2 having the light-shielding wall 2a is formed of a light-shielding resin, and the light-shielding wall 2a also shields light between the condenser lenses 6 and 7.
As shown in FIG. 2, the reflective photointerrupter 1 has smooth outer surfaces 2d and 2e formed in an L-shape corresponding to the condenser lenses 6 and 7, respectively, on a V-shaped portion of the case 2 as shown in FIG. Has formed.
[0007]
In the reflection type photointerrupter 1 shown in FIG. 1, light emitted from the light emitting element 3 is collected by the condenser lens 6 and is irradiated on the front side. Therefore, when the detected object 15 is present in front of the light irradiation direction as shown in the figure, the reflected light from the detected object 15 is condensed by the condensing lens 7 on the light receiving side and enters the light receiving element 4. Then, it is photoelectrically converted and output through the harness 12. Based on the output electric signal, the presence or absence of the detection target 15 is optically detected in a non-contact manner.
In the reflection type photointerrupter 1, as described above, the plurality of external connection harnesses 12 are all drawn out to the rear side of the frame 5 substantially in parallel with the detection center line CL. Therefore, as shown in FIG. 2, the reflective photointerrupter 1 is inserted from the condenser lenses 6 and 7 into the space of the height (length) H and the width W of the outer shape of the case 2 as long as there is space. Since it can be installed without having to worry about the distribution of the harness, it can be installed in a small space.
[0008]
Thereby, even in the vicinity of a movable portion such as between rollers of a feeding roller of a sheet feeding device in the image forming apparatus, the arrangement of the harness 12 can be easily laid out and installed, so that the height of the apparatus can be increased. Space saving can be realized. Further, since the reflection type photo-interrupter 1 can be arranged close to the object to be detected such as paper since the harness 12 does not interfere, even if the power output from the light emitting element 3 is reduced, the object to be detected can be detected. Becomes possible. Accordingly, if the output power of the light emitting element 3 is reduced, the light is emitted from the light emitting element 3 even if the reflection type photointerrupter 1 is provided in the space in the apparatus main body which is reduced by saving the space of the entire apparatus. Since unnecessary light reflected by the light hitting a wall or the like in the apparatus main body and input to the light receiving element 4 is almost eliminated, erroneous detection of the detection target can be prevented.
[0009]
FIG. 3 is a schematic view showing an example of a paper feeder provided with the reflective photointerrupter shown in FIGS. 1 and 2, FIG. 4 is a front view showing the paper feeder, and FIG. FIG. 3 is a schematic configuration diagram illustrating an example of an image forming apparatus provided with the same reference numerals as in FIGS. 1 and 2.
In the copying machine as the image forming apparatus shown in FIG. 5, an optical writing system 43 is provided in an image forming system 44 based on image data read by an optical reading system 42 provided in a copying machine main body 41. A latent image is formed on the photosensitive drum 45, and the developing device 46 of the image forming system 44 converts the latent image into a visible image using toner.
A sheet feeding device 20 is provided on the lower right side of the copying machine main body 41, and a sheet P fed from a sheet feeding cassette 47 of the sheet feeding device 20 is transported upward through the vertical transport path 21 to form an image forming system 44. The visible image (toner image) on the photosensitive drum 45 is transferred there.
[0010]
The sheet P to which the visible image has been transferred is conveyed to a fixing device 48 where the visible image is fixed, and then discharged to an external discharge tray 65 by a pair of discharge rollers 49. Further, at the time of double-sided image formation, the sheet P is conveyed from the reversing conveyance path 61 to the double-sided device 62 by a paper ejection branching claw (not shown), and once stored in the double-sided tray 63, the traveling direction is reversed. From 64, the image is sent again to the image forming system 44, an image is formed on the back surface, and the sheet is discharged onto the sheet discharge tray 65 through the fixing device 48.
Although only one sheet feeding device 20 is shown in FIG. 5 to simplify the drawing, a plurality of sheet feeding devices may be provided as needed. Further, the image forming apparatus having the sheet feeding device is not limited to a copying machine, and can be applied to a facsimile, a printer, and the like without any trouble.
The paper feeding device 20 includes the reflective photo-interrupter 1 described with reference to FIGS. 1 and 2, and a transport roller 22 is disposed on a vertical transport path 21 that transports the paper P in a vertical direction as shown in FIG. are doing.
[0011]
The transport roller 22 includes a plurality of drive rollers 31 formed of a rubber roller that rotates by receiving a driving force from a drive source (not shown), a shaft 33 that fixedly supports the plurality of drive rollers 31 by press-fitting at intervals, and a drive roller. A plurality of driven rollers 32 that are driven and rotated while being pressed against the spring 31 by a biasing force of a spring 35, and a shaft 34 that fixedly supports the plurality of driven rollers 32 by press-fitting at intervals. The shaft 34 of the driven roller 32 is rotatably supported by a bearing 36.
The paper feeder 20 irradiates the reflective photointerrupter 1 to the vicinity of the upper side of the shaft 33 between the drive rollers 31 of the transport roller 22 as shown in FIG. 4 from the light emitting element 3 as shown in FIG. The optical axis 8 of the light is directed downward from the horizontal so that the reflection type photo interrupter 1 can detect the sheet P conveyed on the vertical conveyance path 21.
[0012]
The reflection type photo interrupter 1 is connected to a main body control device (not shown) by a harness 12, and detects the presence or absence of a sheet P conveyed through the vertical conveyance path 21 to thereby determine sheet conveyance timing and sheet non-delivery. Used to monitor stagnation.
Since the reflection type photointerrupter 1 has all the external connection harnesses 12 drawn out to the rear side of the frame 5 as described above, the height (length) H and the width W of the case 2 shown in FIG. If there is space for the external shape, it can be inserted there.
Therefore, as shown in FIG. 3, it is installed near the upper side of the shaft 33 between the drive rollers 31 of the transport roller 22, which is a movable part, and the optical axis 8 of the light emitted from the light emitting element 3 is higher than the horizontal. Even if it arrange | positions so that it may face down, the distribution of the harness 12 can be laid out easily. Therefore, the apparatus can be downsized in the height direction by an amount that does not require a large installation space in the height direction.
In addition, in the portion of the transport roller 22, a slight transport slip occurs due to the load of the transported paper, which may cause the paper powder to drop. By arranging it above the transfer roller 22, it is possible to prevent paper dust falling due to the transfer slip of the transfer roller 22 from adhering to the reflective photointerrupter 1.
[0013]
If another transport roller is provided above the reflective photointerrupter 1 (downstream of the transport), paper powder may fall from the transport roller. Even in this case, since the reflective photointerrupter 1 is arranged such that the optical axis 8 of the light emitted from the light emitting element 3 is directed downward below the horizontal, the dropped paper dust is collected by the condenser lenses 6, 7 ( (See FIGS. 1 and 2).
Further, since the optical axis 8 from the light emitting element 3 is directed downward from the horizontal, the detection point at which the light strikes the paper P is at the nip where the drive roller 31 of the transport roller 22 and the driven roller 32 are in contact. Since it is immediately after, the sheet P can be detected in a stable state without slack or runaway. Therefore, high detection accuracy is obtained.
[0014]
【The invention's effect】
As described above, according to the reflective photointerrupter according to the present invention, the light emitting element is substantially parallel to the detection center line that passes through the intersection of the optical axis of the light emitting element and the optical axis of the light receiving element and intersects perpendicularly with the plane of the frame. Since the external connection harnesses respectively connected to the light receiving element and the light receiving element are pulled out to the rear side of the frame, the external connection harness does not protrude outside the case of the reflection type photointerrupter. A reflective photointerrupter can be inserted. Therefore, installation in a space-saving manner is possible, and space saving in the height direction of the device can be achieved.
Further, according to the paper feeder and the image forming apparatus having the reflective photointerrupter, the optical axis of the light emitted from the light emitting element is set horizontally near the upper side of the shaft between the rollers of the transport roller. Since it is arranged so as to face downward, it is possible to prevent paper dust and the like falling from the paper when the transport roller rotates from attaching to the cover of the reflective photointerrupter.
Further, even when another transport roller is provided above the reflective photointerrupter, even if paper powder falls from the transport roller, the reflective photointerrupter emits light emitted from the light emitting element. Are arranged so that the optical axis is directed downward from the horizontal, so that the dropped paper dust is unlikely to accumulate on the cover. Furthermore, since the optical axis from the light emitting element is directed downward from the horizontal, the detection point for irradiating light to the paper is immediately after the nip of the conveying roller, so that the paper is most stable so that the paper is not loosened or rampaged. Paper detection can be performed in the state. Therefore, high detection accuracy is obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a partial cross section of an embodiment of a reflection type photo interrupter according to the present invention.
FIG. 2 is an external perspective view showing the reflection type photo interrupter.
FIG. 3 is a schematic view showing an example of a sheet feeding device provided with the reflection type photo interrupter shown in FIGS. 1 and 2;
FIG. 4 is a front view showing the sheet feeding device.
FIG. 5 is a schematic configuration diagram illustrating an example of an image forming apparatus including the sheet feeding device.
FIG. 6 is a longitudinal sectional view showing an example of a conventional reflection type photo interrupter.
[Explanation of symbols]
1: reflection type photo interrupter 2: case 2a: light blocking wall 3: light emitting element 4: light receiving element 5: frames 8, 9: optical axis 12: external connection harness 15: object to be detected 20: sheet feeder 21: vertical transport Road 22: Transport rollers 33, 34: Shaft

Claims (3)

A light-emitting element and a light-receiving element are arranged in parallel with a frame in a state of being separated by a light-blocking member, and a case is attached to the frame so as to house the light-emitting element and the light-receiving element. In a reflection type photointerrupter configured to detect the presence or absence of the object to be detected by receiving the light reflected by the body with the light receiving element,
An external connection harness connected to the light emitting element and the light receiving element substantially parallel to a detection center line passing through an intersection of the optical axis of the light emitting element and the optical axis of the light receiving element and perpendicular to the plane of the frame. A reflection type photo-interrupter, wherein the reflection type photo-interrupter is drawn to the back side of the frame. A sheet feeder comprising: the reflective photointerrupter according to claim 1; and a transport roller having a plurality of rollers fixed on a shaft at intervals in a vertical transport path that transports the paper in a vertical direction.
The reflective photo-interrupter is arranged near the upper side of the shaft between the rollers of the transport roller, such that the optical axis of light emitted from the light-emitting element is directed downward from horizontal, and the reflective photo-interrupter is used. A sheet feeding device, wherein a sheet conveyed in the vertical conveyance path can be detected. An image forming apparatus comprising the sheet feeding device according to claim 2.

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