JPH11173912A - Dustproof mechanism for sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dustproof mechanism for sensor with which a sensor can be used for a long time without exchanging a whole protecting film and lowering detection ability. SOLUTION: A photosensor 3 is protected from dust by a case 3 and a protecting film 1. Both the terminal parts of the protecting film 1 are wound around film holders 5A and 5B in the case 3 and the reels of the protecting film 1 on the film holders 5A and 5B are pressed by cleaning rollers 6A and 6B so that dirt on the protecting film 1 can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dustproof mechanism for a sensor, and more particularly to a mechanism for covering an optical sensor or the like with a protective film so as to protect the optical sensor from contamination with external dust.

[0002]

2. Description of the Related Art As a conventional dustproof mechanism of this type of sensor, there is a dustproof mechanism used in a medium detecting device described in Japanese Patent Application Laid-Open No. 4-359652.

FIG. 8 is a cross-sectional view of this conventional dustproof mechanism.

In FIG. 1, a sheet (not shown) is transported in a medium transport guide 57. The light-emitting element 53 and the light-receiving element 56 that form an optical sensor are arranged with the medium transport guide 57 interposed therebetween, and the case 50 that houses the protective film 1 is mounted between the medium transport guide 57 and the light-emitting element 53.
A transport guide portion through hole 59 is provided in the medium transport guide 57 so that light from the light emitting element 53 reaches the light receiving element 56, and case portion through holes 51, 52, and 93 are provided in the case 50. The protective film 1 is made of a material that transmits the light of the light emitting element 53, and is formed of a film holder 5 provided in the case 50.
8A, and the leading end is wound around a film holder 58B in the case 50.

The light emitting portion of the light emitting element 53 is surrounded by a case 50 and the case through hole 52 is covered with a protective film 1 to block the light emitting element 53 from the outside, thereby preventing external dust from adhering to the light emitting element 53. This prevents the optical sensor from deteriorating the ability to detect the paper being transported. However, since the portion of the protective film 1 facing the case through-hole 51 is contaminated with dust, when this portion is contaminated to some extent, the protective film 1 is conveyed by a suitable length by winding it up on a film holder 58B. To go. By repeating this conveyance, the entire protective film 1 is wound up by the film holder 58B, and when the protective film 1 is used up, the case 50 is replaced with a new one.

[0006]

The first problem is that the case 50 needs to be replaced from time to time.

[0007] The reason is that, since the protective film becomes dirty, a part of the protective film cannot be located continuously in the case portion through-hole 51 and must be conveyed. This is because the part is lost.

A second problem is that an end check function for detecting that the entire protective film 1 has been wound on the film holder 58B is required. This results in a complicated structure.

The reason is that it is necessary to detect when the protective film 1 has been used up to replace the case 50.

[0010] An object of the present invention is to shield the sensor from the outside with a protective film so that the sensor is not stained. If the used portion of the protective film becomes dirty, it is transported between reels on which the protective film is wound and used. Repeat that,
Further, by removing the dirt on the protective film, the protective film can be used any number of times, and a dustproof mechanism for the sensor can be used for a long time without replacing the entire protective film without reducing the detection ability. It is in.

[0011]

According to the present invention, there is provided a dustproof mechanism for a sensor, comprising: a protective film for traveling in front of a detecting portion (4 in FIG. 1) of the sensor (2 in FIG. 1) to protect the detecting portion from dust; A first film holder (5A in FIG. 1) for winding one end of (1 in FIG. 1), and a second film holder (5B in FIG. 1) for winding the other end of the protective film;
A cleaning roller (6A, 6B in FIG. 1) for removing dirt from the protective film.

The dustproof mechanism of the sensor according to the present invention has a central portion (3C in FIG. 1) and first and second holder portions (3A and 3B in FIG. 1) provided on both sides of the central portion.
(3 in FIG. 1), first and second film holders (5A and 5B in FIG. 1) provided in the first and second holder portions, respectively, and the center of the case. A through-hole (11 in FIG. 1) provided in a front part of a sensor (2 in FIG. 1) inserted into the portion, one end of the sensor is wound by the first film holder and the other end is the second film. And a protective film (1 in FIG. 1) in which an intermediate portion of these wound portions crosses the through hole, and the protective film wound by the first and second film holders. One or a plurality of cleaning rollers (6A, 6B in FIG. 1) pressed against at least one of the film reels. Preferably, the first and second film holders and these film holders are provided. The reel of the protective film wound around the reel is housed in the first and second holder portions, and the outer periphery of at least one of the reels of the protective film wound around the first and second film holders. A window (15 in FIG. 5) for exposing a surface to the outside is provided in the case, and the cleaning roller is provided outside the case and the protective film wound on the first and second film holders through the window. Or a re-cleaning roller (16A, 16B in FIG. 7) for removing dirt from the cleaning roller by pressing the cleaning roller against at least one of the reels. The exposed window for the re-cleaning roller (1 in FIG. 7)
7) is provided in the case, and the re-cleaning roller performs the cleaning only when a diameter of a reel of the protective film wound on the pressed first and second holders is equal to or larger than a predetermined value. So that it can be pressed against the rollers.

The cleaning roller (6 in FIG. 1)
A, 6B) is the pressing protective film (FIG. 1)
1) A moving axis that moves along a linear rail (9A, 9B in FIG. 1) passing through the center of the first or second film holder (5A, 5B in FIG. 1) around which the reel is wound. (13A, 13B in FIG. 1), and is urged in the direction of the film holder by a spring (21 in FIG. 3). The tip of the central portion (3C in FIG. 1) has the through hole (3C). The protective film has a lid (8 in FIG. 1) made of an elastic body that is in close contact with the side surface of the sensor (2 in FIG. 1) inserted in a state facing the 11) in FIG. Seals the tip of the sensor while being stretched across the through hole, and the first and second holder portions each have a slit (14 in FIG. 5) for passing the protective film through the through hole. Have the slit on the protective film on both sides Brushes et contact (14 in FIG. 6)
May be provided.

According to the dustproof mechanism of the sensor of the present invention, the protective film is contaminated with dust, but the dirt on the protective film is removed by a cleaning roller to keep the protective film clean and prevent the sensor's detection ability from deteriorating.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 respectively show a first embodiment of the present invention.
It is a cross-sectional view and a perspective view of a dustproof mechanism of the sensor according to the embodiment.

1 and 2, the inside of the case 3 is divided into a central portion 3C and holder portions 3A and 3B on both sides thereof. Film holders 5A and 5B are provided at the centers of the holder portions 3A and 3B, respectively, so as to be vertically rotatable.

The lower surface of the central portion 3C is composed of an openable and closable lid 10, the upper surface is covered with a flat plate, the front surface is provided with a through hole 11, and the rear surface is formed of an elastic member on both sides except for the middle opening 12. Is provided.

The film holders 5A, 5B at both ends
The protective film 1 is wound around a slit 14 provided in a boundary wall between the central portion 3C and the holder portions 3A and 3B, and covers the through hole 11.

The optical sensor 2 is fixed to a medium transport mechanism (not shown). With the lid 10 open, the central part 3
C is positioned on the optical sensor 2, the case 3 is lowered, the tip of the optical sensor 2 is inserted into the central portion 3C, and the case 3 is attached to the medium transport mechanism.
Close. In this state, the edge of the lid 8 is in close contact with the side surface of the optical sensor 2, and the tip of the optical sensor 2 is sealed in the central portion 3C to be protected from dust.

The protective film 1 is made of a material through which light having a sensitivity to the optical sensor 2 is transmitted. A medium conveyed through a medium guide (not shown) located on the front side of the case 3 is detected by the optical sensor 2. That is, light from a light source (not shown) provided to face the optical sensor 2
And is detected by the light receiving surface 4 at the tip of the optical sensor 2. When there is a medium at a position facing the through hole 11, the light from the light source is blocked by the medium, does not reach the light receiving surface 4, and is not detected.

The film holders 5A and 5B are connected to a power shaft 7 rotated by a drive unit (not shown), and can transport the protective film 1 in any direction on the left and right. Cleaning rollers 6A and 6B are provided corresponding to the film holders 5A and 5B, respectively. The cleaning roller 6B is rotatably attached to a moving shaft 13B that can move along the cleaning roller moving rail 9B as shown in FIGS.
The cleaning roller moving rail 9B is provided on a straight line passing through the center of the film holder 5B. The cleaning roller 6B is pressed against the reel of the protective film 1 wound around the film holder 5B by a spring 21 having one end fixed to the moving shaft 13B and the other end fixed to the bearing of the film holder 5B.

Similarly, the cleaning roller 6A has a moving shaft 13A guided by the cleaning roller moving rail 9A.
And is pressed against a reel of the protective film 1 on the film holder 5A by a spring.

Next, the operation of this embodiment will be described.

First, when the protective film 1 is wound on the film holder 5A, when the portion of the protective film 1 located in the through hole 11 becomes contaminated with dust to some extent, the protective film 1 is moved to a predetermined length. Is wound around the film holder 5B and transported. At this time, the cleaning rollers 6A and 6B also rotate with the rotation of the reel of the protective film 1 on the film holders 5A and 5B, and the cleaning rollers 6A and 6B clean the protective film 1.

As the transport of the protective film 1 for a predetermined length is repeated, the diameter of the reel on the film holder 5B increases, and the cleaning roller 6B is pushed along the cleaning roller moving rail 9B so as to be pushed out onto the reel. Move away from. At the same time, the diameter of the reel on the film holder 5A decreases, and the cleaning roller 6A moves toward the film holder 5A along the cleaning roller moving rail 9A so as to be attracted to the reel.

After the protective film 1 is fully wound around the film holder 5B, when the protective film 1 becomes dirty, it is rewound to the film holder 5A by a predetermined length. Also at this time, the cleaning rollers 6A, 6A
B cleans the protective film 1. By repeating this operation, the optical sensor 2
Can be protected from dust, and the state where the protective film 1 is clean and the optical sensor 2 has high sensitivity can be maintained.

Although the structure for attaching the case 3 to the medium transport mechanism is not shown, it is preferable to make the structure easy to attach and detach. By adopting such a structure, when the protective film 1 is damaged or when the dirt on the protective film 1 cannot be sufficiently removed by the cleaning rollers 6A and 6B, the case 3 is replaced with a new one. can do.

FIG. 5 is a cross-sectional view of the dustproof mechanism of the sensor according to the second embodiment of the present invention.

This embodiment is almost the same as the first embodiment shown in FIG. 1, but differs in the following points. Film holders 5A and 5B are provided outside the center of holder portions 3A and 3B, and windows 15 are provided on both sides of case 3 to expose the reel of protective film 1 wound around film holders 5A and 5B to the outside. The cleaning rollers 6A and 6B are arranged outside the case 3. The cleaning roller moving rails 9A and 9B fixed to the case 3 are provided outside the case 3, and the moving shaft 13 moves along the cleaning roller moving rails 9A and 9B.
Cleaning rollers 6A and 6B are rotatably attached to A and 13B. The cleaning roller 6
A and 6B are pressed against the reels on the film holders 5A and 5B by springs.

FIG. 6 is an enlarged view of part A of FIG.
A brush 20 is provided in the slit 14 so as to contact the protective film 1 from both sides, and the holder 3 communicates with the outside through the window 15.
A, 3B is completely shut off from the central portion 3C, and dust entering the holder portions 3A, 3B from the outside through the window 15 is further prevented from entering the central portion 3C and soiling the light receiving surface 4 of the optical sensor 2. . In addition, since the dirt attached to the protective film 1 is removed by the brush 20 with the holders 3A and 3B, such dirt is prevented from adhering to the light receiving surface 4.

If the dustproof mechanism of the sensor of this embodiment is used for a long time, dirt accumulates on the cleaning rollers 6A and 6B, but since the cleaning rollers 6A and 6B are provided outside the case 3, It is easy to clean the cleaning rollers 6A, 6B with a cloth or the like.

The cleaning rollers 6A and 6B are configured to be detachable from the moving shafts 13A and 13B. If a large amount of dirt is accumulated on the cleaning rollers 6A and 6B, the cleaning rollers 6A and 6B are replaced with new ones. You may make it.

FIG. 4 is a cross-sectional view of a dustproof mechanism of a sensor according to a third embodiment of the present invention.

This embodiment is almost the same as the first embodiment shown in FIG. 1, except that the re-cleaning roller 16A,
16B. Re-cleaning rollers 16A, 16B are attached to cleaning roller moving rails 9A, 9B on which cleaning rollers 6A, 6B are guided.
The re-cleaning rollers 16A and 16B are also guided by springs (not shown) by the film holders 5A and 5B.
However, the re-cleaning rollers 16A and 16B cannot be moved within a certain distance from the film holders 5A and 5B by a stopper (not shown).
Only when the diameter of the reel of the protective film 1 on B is about 80% or more of the maximum diameter, the re-cleaning rollers 16A and 16B come into contact with the cleaning rollers 6A and 6B, rotate with them, and clean them. The rollers 6A and 6B are cleaned. The re-cleaning rollers 16A and 16B are exposed to the outside through a window 17 provided in the case 3.

If the dustproof mechanism of the sensor of the present embodiment is used for a long time, the cleaning rollers 6A and 6B are also stained, but the stains on the cleaning rollers 6A and 6B are removed by the re-cleaning rollers 16A and 16B. If the dustproof mechanism of this sensor is used for a longer period, the re-cleaning roller 16
Although the dirt is accumulated on A and 16B, the re-cleaning rollers 16A and 16B can be cleaned with a cloth or the like through the window 17.

The present invention is not limited to optical sensors and can be used for dust prevention of various sensors such as magnetic sensors.

In the above embodiment, the case 3 is described as being removable from the medium transport mechanism. However, the present invention can be applied even if the case cannot be removed from the medium transport mechanism. However, in this case, replacement of the cleaning roller, removal of dirt on the cleaning roller, and the like are indispensable. Also, the present invention does not include a case,
The present invention can also be applied to the case where stains on a protective film wound around a film holder provided in a medium transport mechanism or the like are removed.

In the above-described embodiment, two cleaning rollers 6A and 6B are provided for the two reels on the film holders 5A and 5B, but one cleaning roller is provided for only one of the two reels. A cleaning roller may be provided. However, in this case, the dirt received by the portion of the protective film 1 located in the through hole 11 is such that the dirt on the protective film is removed only when the protective film 1 is transported toward the film holder provided with the cleaning roller. Therefore, when transporting the protective film in the reverse direction, it is better to return the protective film to another film holder quickly without stopping it for dust prevention.

In addition, an appropriate frictional force is applied to the rotation of the cleaning roller, so that when the reel of the protective film on the film holder rotates, a slight slippage occurs between the reel and the cleaning roller, and the cleaning roller moves on the protective film. Dirt may be wiped off.

The structure for pressing the cleaning roller against the protective film on the film holder is not limited to the structure described in the above embodiment. For example, a moving shaft is fixed to the other end of a leaf spring whose one end is fixed to the case, a cleaning roller is rotatably attached to this moving shaft, and the cleaning roller is pressed against the reel of the protective film by the spring force of the leaf spring. You may do so. The same applies to the re-cleaning roller shown in FIG.

The case 3 and the lid 10 shown in FIG. 3 may be made of plastic, for example. In this case, the lid 10 is opened and closed by bending using the elasticity of the plastic, and the locking structure made of plastic provided on both the case 3 and the lid 10 is engaged by using the elasticity of the plastic. Can be locked in a closed state. In the case where the medium guide located on the entire surface of the case 3 of the medium transport mechanism can be removed, if the tip of the sensor 2 can be inserted from the opening 12 between the lids 8 made of an elastic body into the central part 3C, the lid 10 can be removed. It is not necessary to open and close the portion, and the portion may be covered with a flat plate integrated with the case 3.

The brush 20 shown in FIG. 6 is similar to the brush 20 shown in FIG.
In addition to the embodiment, the present invention can be applied to the first and third embodiments shown in FIGS.

[0044]

The effect of the present invention is that the mechanism for dust-proofing the sensor with the protective film does not require replacement of the protective film. Also, there is no need to replace the case containing the protective film.

The reason is that dirt on the protective film is removed by the cleaning roller.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a dustproof mechanism of a sensor according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a dustproof mechanism of the sensor shown in FIG.

FIG. 3 is an enlarged cross-sectional view showing a film holder 5B and a cleaning roller 6B in FIG. 1;

FIG. 4 is a sectional view taken along the line BB of FIG. 3;

FIG. 5 is a cross-sectional view of a dustproof mechanism of a sensor according to a second embodiment of the present invention.

FIG. 6 is an enlarged view of a portion A in FIG. 5;

FIG. 7 is a cross-sectional view of a dustproof mechanism of a sensor according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view of a dustproof mechanism of a conventional sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protective film 2 Optical sensor 3 Case 3A, 3B Holder part 3C Central part 4 Light receiving surface 5A, 5B Film holder 6A, 6B Cleaning roller 7 Power shaft 8 Lid 9A, 9B Cleaning roller moving rail 10 Lid 11 Through hole 12 Opening 13A , 13B Moving shaft 14 Slit 15 Window 16A, 16B Re-cleaning roller 17 Window 20 Brush 21 Spring 50 Case 51 Case part through hole 52 Case part through hole 53 Light emitting element 56 Light receiving element 57 Medium transport guide 58A, 58B Film holder 59 Transport guide Part through-hole 93 Case part through-hole

Claims (10)

[Claims] 1. A first film holder which winds around one end of a protective film for traveling in front of a detecting section of a sensor and protects the detecting section from dust, and winds up the other end side of the protective film. A dustproof mechanism for a sensor, comprising: a second film holder; and a cleaning roller for removing dirt from the protective film. 2. A case whose interior is divided into a central part and first and second holder parts provided on both sides of the central part, and a first part provided in each of the first and second holder parts. And a second film holder, a through-hole provided in a front part of a sensor inserted into the central portion of the case, and one end side wound around the first film holder and the other end side closed the first film holder. A protective film which is wound around the film holder of No. 2 and an intermediate portion of these wound portions passes across the through hole;
And 1 pressed against at least one of the reels of the protective film wound on the second film holder.
Alternatively, a dustproof mechanism for a sensor, including a plurality of cleaning rollers. 3. The method according to claim 1, wherein the first and second film holders, the reel of the protective film wound around these film holders, and the cleaning roller are housed in the first and second holder portions. 3. A dustproof mechanism for a sensor according to claim 2, wherein: 4. The first and second film holders and the reel of the protective film wound around these film holders are housed in the first and second holder portions, and the first and second film holders are provided. A window is provided in the case to expose at least one outer peripheral surface of the reel of the protective film wound on the film holder to the outside, and the cleaning roller is provided outside the case and the first and second cleaning rollers are provided through the window. The dustproof mechanism for a sensor according to claim 2, wherein the dustproof mechanism is pressed against at least one of the reels of the protective film wound around the film holder. 5. A dustproof mechanism for a sensor according to claim 3, further comprising a re-cleaning roller pressed against the cleaning roller to remove dirt from the cleaning roller. 6. The dustproof mechanism for a sensor according to claim 5, wherein a window for a re-cleaning roller that exposes the re-cleaning roller to the outside is provided in the case. 7. The re-cleaning roller is pressed against the cleaning roller only when a diameter of a reel of the protective film wound on the pressed first and second holders is equal to or larger than a predetermined value. 7. A dustproof mechanism for a sensor according to claim 5, wherein: 8. The cleaning roller according to claim 1, wherein said first protective film is wound around a reel of said protective film.
8. The apparatus according to claim 1, wherein said second holder is rotatably mounted on a moving shaft moving along a linear rail passing through the center of said second holder, and is urged toward said holder by a spring. The dustproof mechanism of the sensor according to any one of the above. 9. The central portion has a lid made of an elastic body that is in close contact with a side surface of the sensor inserted with a front end facing the through hole and a rear end protruding outside, and the protective film is 8. The sensor according to claim 2, wherein the tip of the sensor is sealed while being stretched across the through hole.
The dustproof mechanism of the sensor according to any one of the above. 10. The first and second holder portions,
8. A brush, wherein each of the slits has a slit for passing the protective film through the through hole, and a brush is provided on the slit so as to contact the protective film from both sides.
A dustproof mechanism for a sensor according to any one of claims 9 to 13.