JP2847526B2 - Magnetic powder detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic powder such as a toner used for an electrophotographic copying machine, a facsimile, a printer, or the like, in which the remaining amount in a container is small. The present invention relates to a magnetic powder detecting device for detecting when this happens and outputting a signal.

[Conventional technology]

Conventionally, as such a magnetic powder detection device, near the bottom of the toner container, outside the side surface of the toner container,
A magnet attached to the tip of the actuator is provided, and when toner is present in the toner container facing the magnet, the magnet is attracted toward the toner, so that the actuator operates. The operation of this actuator turns on or off a switch or the like optically, magnetically, or mechanically. When no toner is present in the toner container facing the magnet, the magnet faces the toner. There is known a configuration in which the switch or the like is kept off or on when the actuator is not operated and the actuator does not operate.

[Problems to be solved by the invention]

However, since the magnetic powder detection device having such a configuration mechanically detects the toner, it may malfunction due to vibration or the like, and it is necessary to increase the mounting accuracy of the magnet and the actuator to the toner container. This makes the assembly complicated and cumbersome.
In addition, since the operation of the actuator is delicate, accurate operation may not be obtained due to adhesion of dust and the like. Further, since a space for operating the actuator is required, the configuration of the entire apparatus becomes large. And other problems.

For this reason, at least a part of the toner container is formed of a transparent material, and the light emitting element and the light receiving element are respectively formed so that an optical path from the light emitting element to the light receiving element passes through the transparent part of the toner container. There is also an optical detection device disposed outside near the bottom so as to detect the presence of toner when the optical path is blocked by toner.

However, in this apparatus, since a part of the toner container is formed of a transparent material, the production of the toner container is troublesome, the cost is increased, and when dust and dirt adhere to the toner container, There was a malfunction.

In addition, there is a magnetic detection head in which a detection coil is wound around a magnetic core at the bottom of the toner container so that a change in a magnetic circuit of the magnetic core is magnetically detected from an output of the detection coil to detect toner. Requires an oscillating circuit for inputting a signal to a coil separately wound around the magnetic core of the magnetic detection head, and also requires a circuit for processing the signal from the detection coil, which complicates the overall circuit configuration And the cost increases.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a magnetic powder detecting device which is easy to mount, free from malfunctions due to vibration, dust and the like, has a small configuration, and is low in cost.

[Means for Solving the Problems] According to the present invention, the object is to provide two magnets arranged in parallel in the same direction so that the same poles correspond to each other, and one of the magnets The magnet has two opposing magnetoresistive elements such that the center of the end face of one of the magnets and the center of the magnetoresistive chip substantially coincide with each other with respect to both end faces of the magnet. The detection direction is arranged so as to correspond to the horizontal direction facing the other magnet and the direction perpendicular to the direction of the opposing magnetoresistive element, and preferably with respect to the container in which the magnetic powder is stored. When the magnetic powder is mounted horizontally on the bottom surface of the container or laterally on the side surface of the container, and magnetic powder is present in an upper region adjacent to the two magnets, the change in the resistance value of the magnetoresistive element is determined. To detect the presence of the magnetic powder. This is achieved by the magnetic powder detection device described above.

(Operation)

According to the present invention, when the magnetic powder is not present in the upper region adjacent to the two magnets, that is, in the side region when the magnetic powder is mounted laterally with respect to the side surface of the container or the like, Since the two magnets are arranged in such a manner that the same poles are opposed to each other, the direction of the line of magnetic force that goes from the end face of the magnet to the outside or enters the end face of the magnet from the outside,
In other words, the magnetic force line vector is repelled by the other magnet because the ends of the other magnets facing each other have the same polarity. Therefore, the horizontal component increases as a whole, and the vertical component decreases, and these are detected by the appropriate processing circuit as the resistance value in each direction of the magnetoresistive element, so that the magnetic powder does not exist. Is detected.

On the other hand, when the magnetic powder exists in the upper region adjacent to the two magnets, the presence of the magnetic powder causes
The magnetic force vector at the end face of the magnet is pulled by the magnetic powder, so that the horizontal component is reduced and the vertical component is increased as compared with the case where there is no magnetic powder. Therefore,
These are detected by a suitable processing circuit as resistance values in each direction of the magnetoresistive element,
The presence of the magnetic powder is detected.

As described above, according to the present invention, since no mechanical configuration is used for detecting the magnetic powder, there is no malfunction due to vibration or clogging of dust, etc.
When mounting the magnetic powder on a storage container or the like, very little precision is required, so that the mounting is simple, and if the whole is integrated with a resin mold, the mounting is even easier and the maintenance becomes easier. In addition, compared to an optical detection device, a conventional storage container for magnetic powder can be used as it is, and there is no possibility of erroneously detecting dust or the like as magnetic powder, which is simpler. With such a configuration, it can be manufactured at low cost.

〔Example〕

Hereinafter, the present invention will be described in detail based on one embodiment shown in the drawings.

FIG. 1 shows an embodiment of a magnetic powder detecting device according to the present invention.

The magnetic powder detection device 10 has two magnets 11 and 12 arranged side by side so as to be parallel to each other and have the same polarity.
And two magnetoresistive elements 13 and 14 disposed so as to face both end surfaces of one of the magnets 11 and 12, and a case or a resin as shown as a whole by a chain line. They are integrated by a mold 15, and the upper surface is formed as a magnetic sensing surface 15a.

As shown in FIG. 2, the magneto-resistive elements 13 and 14 are connected to terminals 13b and 13c (14
b, 14c) and the terminals 13c, 13d (14c,
14d), and the resistance between the terminals 13b, 13c (14b, 14c) becomes large and the terminals 13c, 13d (14c, 14d) increase with respect to the magnetic field lines in the vertical y direction. ) To reduce the resistance value.

The magnetic powder detection device 10 according to the present invention is configured as described above.
The magnetic sensing surface 15 can be mounted horizontally on the bottom of a container such as a storage container in which the magnetic powder to be detected is stored, or mounted sideways near the bottom of the side of the container.
a is brought into contact with the container.

According to the magnetic powder detecting device 10 attached in this manner, the container (not shown) is adjacent to the magnetic sensing surface 15a.
If there is no magnetic powder such as toner inside, each magnet 11, 12
As shown in FIG. 3 (A), the magnetic force lines vectors from the end faces of the magnets 11 and 12 repel each other and the external And is represented as a vector indicated by a double arrow A as a whole. In this case, since the two magnets 11 and 12 are provided, the magnetoresistive chips 13a and 1a of the magnetoresistive elements 13 and 14 are arranged with respect to the center of the end face of one magnet 11.
Even if 4a is not centered accurately, the repulsion generated between the magnet 12 and the magnet 12 results in magnetic force line vectors substantially directed outward, so that the positioning of the magnetoresistive elements 13, 14 is easily performed. be able to.

Due to such a line of magnetic force A, the resistance value between the terminals 13b and 13c and between the terminals 14b and 4c of the magnetoresistive elements 13 and 14 decreases, and the resistance value between the terminals 13c and 13d and the terminals 14c and 14d increases. Therefore, by detecting these resistance values by an appropriate circuit, it is detected that the magnetic powder does not exist in the region adjacent to the magnetic sensing surface 15a.

Here, as shown in FIG. 3B, when the magnetic powder 16 is present in a region adjacent to the magnetic sensing surface 15a in the container, each magnet 11 , 12
Since the direction of the lines of magnetic force extending outward from the end face of the magnetic field is pulled by the magnetic powder 16, the lines of magnetic force extend outward as indicated by arrows, and are represented as a vector indicated by a double arrow B as a whole.

As a result, the component of the magnetic force vector B in the x-direction decreases and the component in the y-direction increases compared to the case where the magnetic powder 16 is not provided, so that the terminals 13b of the magnetoresistive elements 13 and 14 are increased. , 13c and the resistance value between the terminals 14b, 14c,
Further, since the resistance between the terminals 13c and 13d and the terminals 14c and 14d becomes small, by detecting these resistances by an appropriate circuit, based on the change from the resistance when there is no magnetic powder 16 described above. Thus, it can be detected that the magnetic powder exists in the region adjacent to the magnetic sensing surface 15a.

Thereby, when the remaining amount of the magnetic powder is low in a container such as a storage container of the magnetic powder, it is possible to detect the remaining amount, and display by appropriate means based on the detection result. Or automatically replenish the magnetic powder.

In the above-described embodiment, the present magnetic powder detection device
Although the case where 10 is mounted near the bottom of the container has been described, if it is mounted at an appropriate height position on the side surface of this container, it is determined whether the amount of magnetic powder in the container is greater than or equal to a desired amount or less. It is also possible to detect.

In addition, the magnetic powder detecting device 10 has a resin mold 15
Of course, when formed, it is also possible to dispose it in the container.

〔The invention's effect〕

As described above, according to the present invention, the upper region adjacent to the two magnets (that is, the side region when the magnet is mounted laterally with respect to the side surface of the container or the like of the magnetic powder).
When no magnetic powder is present, since the two magnets are arranged in such a manner that the same poles are opposed to each other, the direction of the magnetic force lines from the end face of the magnet to the outside or from the outside to the end face of the magnet That is, the magnetic force vector is repelled from the other magnet since the end of the other magnet facing is the same polarity, so that the horizontal component increases as a whole and the vertical component decreases, By detecting these as resistance values in the respective directions of the magnetoresistive element by an appropriate processing circuit, it is detected that no magnetic powder is present.

On the other hand, when the magnetic powder is present in the upper region adjacent to the two magnets, the presence of the magnetic powder causes the magnetic force vector at the end face of the magnet to be pulled by the magnetic powder, and there is no magnetic powder. Since the horizontal component decreases and the vertical component increases as compared with the case, the presence of the magnetic powder is detected by detecting these as a resistance value in each direction of the magnetoresistive element by an appropriate processing circuit. Is to be detected.

Therefore, according to the present invention, since a mechanical structure is not used for detecting magnetic powder as in the conventional method,
There is no malfunction due to vibration or clogging of dust, etc., and the device can be made compact. In addition, the mounting of the magnetic powder to a storage container or the like does not require much precision, so that the mounting is simplified.

Further, if the whole is integrated by a resin mold, it can be mounted more easily and maintenance becomes easier. Further, as compared with an optical detection device, a conventional magnetic powder storage container can be used as it is, and furthermore, there is no erroneous detection of dust or the like as a magnetic powder, which is simpler. With the configuration, it can be manufactured at low cost.

Thus, according to the present invention, installation is simple and vibration,
An extremely excellent magnetic powder detecting device which is free from malfunction due to dust or the like, has a small configuration, and is low in cost can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing the configuration of an embodiment of a magnetic powder detecting device according to the present invention, FIG. 2 is an enlarged front view of the magnetoresistive element shown in FIG. 1, and FIG. FIG. 7A is a schematic diagram showing a detection state of the body detection device, in which FIG. 7A shows a case where there is no magnetic powder and FIG. Reference numeral 10: Magnetic powder detection device; 11, 12, Magnet; 13, 14, Magnetic resistance element; 15, Case or resin mold; 15a, Magnetic sensing surface; 16, Magnetic powder.

Claims (4)

(57) [Claims] 1. Two magnets arranged in parallel in the same direction so that the same poles correspond to each other, and an end face of one of the magnets with respect to both end faces of one of the magnets. And two magnetoresistive elements facing each other so that the center of the magnetoresistive chip substantially coincides with the center of the magnetoresistive chip. The detection direction is arranged so as to correspond to the direction perpendicular to the direction of the resistance element. When the magnetic powder exists in the upper region adjacent to the two magnets, the resistance value of the magnetoresistance element Detect changes in
A magnetic powder detecting device, wherein the presence of the magnetic powder is detected. 2. The magnetic powder detecting device according to claim 1, wherein the magnet and the magnetoresistive element are formed as a chip integrated by a resin mold. 3. The magnetic powder detecting device according to claim 1, wherein the magnetic powder detecting device is mounted horizontally on a bottom surface of the container in which the magnetic powder is stored. 4. The magnetic powder detecting device according to claim 1, wherein the magnetic powder detecting device is mounted laterally on a side surface of the container in which the magnetic powder is stored.