JP5359537B2 - Powder remaining amount detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a residual powder quantity detecting device that correctly detects a quantity of residual powder containing magnetic substance. <P>SOLUTION: In the residual powder quantity detecting device, a nonmagnetic sheet 18 formed from a nonmagnetic body is attached to an area, located substantially in the middle, between the N and S pole ends of the side 17A of the magnet 17 on the lead switch 20 side. Consequently, the amount of attracted magnetic substance 27 is reduced in the area of the nonmagnetic sheet 18, and magnetic force lines forming a closed loop decreases, within the range of the attached magnetic substances 27; and thus, the magnetic force reaching the lead switch 20 can be increased. Hence, the prevents degradation in the operating sensitivity of the lead switch 20 and achieves the correct detection of a quantity of residual powder. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder remaining amount detection device that detects the amount of powder remaining in a powder container, for example, a powder container used in an image forming apparatus such as a copying machine, a facsimile, or a printer that uses toner that is powder. The present invention relates to a powder remaining amount detection device that detects the remaining amount of powder in a container.

  Conventionally, the powder remaining amount detection device disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 11-84849) includes a magnet whose swing range changes according to the amount of powder remaining in the powder container, and is a reed switch. The remaining amount of powder is detected by detecting the swing range of the magnet.

  However, in the conventional powder remaining amount detection device, when the powder contained in the powder container contains a magnetic material, the magnetic material adheres to the magnet and the state of the lines of magnetic force generated from the magnet changes. There is a problem that the operation of the reed switch becomes unstable and the remaining amount of powder cannot be detected accurately.

JP 11-84849 A

  Accordingly, an object of the present invention is to provide a powder remaining amount detecting device capable of accurately detecting the remaining amount of powder containing a magnetic substance.

In order to solve the above-described problem, a powder remaining amount detection device according to the present invention includes a swing member that is pivotally supported so as to be swingable in a powder container that stores powder containing a magnetic material ,
A magnet attached to the rocking member and rocked together with the rocking member and displaced within the rocking range according to the amount of powder stored in the powder container;
The magnetic field incident from the magnet when the magnet is at a predetermined position within the swing range is greater than the magnetic field incident from the magnet when the magnet is not at the predetermined position. A magnetic field detector arranged to be,
An adhesion suppressing structure that is disposed between the N extreme and the S extreme of the magnet and suppresses the adhesion of the magnetic substance contained in the powder to the magnet ;
The adhesion suppression structure is characterized in that the magnet is provided in a part between the N extreme and the S extreme on the side facing the magnetic field detection unit .

According to this invention, since the adhesion suppressing structure suppresses the adhesion of the magnetic substance contained in the powder to the magnet, the magnetic field generated by the magnet is stabilized when the powder contains the magnetic substance. Can be made. Therefore, the magnetic field detector can reliably detect the magnetic field from the magnet when the magnet is at a predetermined position within the swing range, and the remaining amount of powder in the powder container Can be detected accurately.

In the powder remaining amount detection device according to one embodiment, the magnetic field detection unit is
The powder is turned on when the magnet is at a predetermined position within the swing range, and turned off when the magnet is not at a predetermined position within the swing range. It is a reed switch arranged outside the body container.

  According to this embodiment, whether or not the magnet is in the predetermined position can be detected based on whether the reed switch is on or off.

  Moreover, in the powder residual amount detection apparatus of one Embodiment, the said adhesion suppression structure is a nonmagnetic member attached between N extreme and S extreme of the said magnet.

  According to this embodiment, it is possible to prevent the magnetic material from adhering to the magnet with a simple structure in which the nonmagnetic member is attached between the N extreme and the S extreme of the magnet.

In the powder remaining amount detection device according to one embodiment, the nonmagnetic member is
The magnet is disposed at substantially the center between the N extreme and the S extreme of the magnet and has a length that is not less than one third and not more than one half of the length between the N extreme and the S extreme of the magnet, and The region of the magnet on the side of the magnetic field detection unit is not less than one third and not more than one half.

  According to this embodiment, since the non-magnetic member covers a region that is approximately 1/3 or more and 1/2 or less of the region on the magnetic field detection unit side of the magnet, the magnetic force from the magnet is insufficient. The effect of preventing the adhesion of the magnetic material can be sufficiently exerted without incurring. When the non-magnetic member covers less than about 1/3 of the region on the magnetic field detection unit side of the magnet, the effect of preventing the adhesion of the magnetic material becomes insufficient. On the other hand, when the non-magnetic member covers an area of the magnet on the side of the magnetic field detection unit that exceeds approximately 1/2 of the center, the magnetic force reaching the magnetic field detection unit from the magnet is insufficient. .

  According to the powder remaining amount detecting device of the present invention, the adhesion of the magnetic substance to the magnet is suppressed by the adhesion suppressing structure, so that when the powder contains the magnetic substance, the magnetic field generated by the magnet is stabilized. Can do. Therefore, the magnetic field detector can reliably detect the magnetic field from the magnet when the magnet is at a predetermined position within the swing range, and the remaining amount of powder in the powder container Can be detected accurately.

It is a figure which shows typically the powder supply apparatus and developing device unit which have embodiment of the powder residual amount detection apparatus of this invention. It is a figure which shows a mode that the powder container of the said powder supply apparatus was seen from the upper direction (supply port side) to the downward direction (supply port side). It is a figure which shows the magnet by which the nonmagnetic sheet | seat was affixed on the side surface in the powder residual amount detection apparatus of the said embodiment. 1 is a diagram schematically showing a powder supply apparatus in which powder 2 is sufficiently stored in a powder container 10. 1 is a diagram schematically showing a powder supply apparatus in which a small amount of powder 2 is stored in a powder container 10. It is a figure which shows typically the magnetic force line between the iron piece of a reed switch, and a magnet in the powder residual amount detection apparatus of the said embodiment. It is a figure which shows typically the magnetic force line between the iron piece of a reed switch, and a magnet in the comparative example with which the magnetic body has not adhered to the magnet. It is a figure which shows typically the magnetic force line between the iron piece of a reed switch, and a magnet in the comparative example by which the nonmagnetic sheet | seat is affixed on the magnet.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 schematically shows a powder supply device having a toner bottle 11 and a powder container 10 and a developer unit 8 to which a powder 2 obtained by mixing toner and developer is supplied from the powder supply device. FIG.

  The toner bottle 11 is filled with powder 2 in which a toner and a developer are mixed, and the powder 2 is supplied from a replenishing port 13 to the powder container 10. A powder 2 in which toner and developer are mixed is accommodated. The toner bottle 11 has a substantially cylindrical shape, and a spiral groove (not shown) is formed on the inner peripheral surface. Therefore, the toner bottle 11 is rotationally driven by a rotational drive unit (not shown) with the cylindrical shaft as the rotation center axis, whereby the powder 2 is pushed out in the axial direction by the spiral groove, and the powder container 11 receives the powder from the supply port 13. It is supplied into the container 10.

  In the powder container 10, a stirring plate 15 having a support shaft 14 pivotally supported at the upper part in the powder container 10 is provided. The stirring plate 15 as a swing member is centered on the support shaft 14. Rotation is possible. FIG. 2 shows a state in which the powder container 10 is viewed from the upper side (supply port 13 side) to the lower side (supply port 7 side). As shown in FIG. 2, a plurality of through holes 16 are formed in the stirring plate 15, and a magnet 17 is fixed to the front end portion of the side surface 15 </ b> A of the stirring plate 15.

  The magnet 17 has a rod shape, and a nonmagnetic sheet 18 made of a nonmagnetic material is attached to the approximate center of the side surface 17A. As the nonmagnetic material, for example, nonmagnetic materials such as nylon, polyvinyl, and resin, nonmagnetic metals such as aluminum and brass, ceramics, and the like can be used.

Further, in this embodiment, the surface of the non-magnetic sheet 18 that has been subjected to a treatment that reduces the friction coefficient, such as a Teflon (registered trademark) coat, is used. As shown in FIG. 3, when the length of the sheet 18 is L2 (mm) and the length from the N extreme to the S extreme of the substantially rectangular side surface 17A of the magnet 17 is L1 (mm), the following formula ( L2 and L1 were set to satisfy 1).
(1/3) × L1 ≦ L2 ≦ (1/2) × L1 (1)

  Therefore, the sheet 18 made of the non-magnetic material covers an area that is one third or more and one half or less of the area of the side surface 17A of the magnet 17.

  On the other hand, a reed switch 20 as a magnetic field detector is disposed outside the powder container 10 so as to face the side wall 10A of the powder container 10. The reed switch 20 is disposed so as to face the magnet 17 when the magnet 17 that swings together with the stirring plate 15 that swings around the support shaft 14 is in a predetermined swing position. The magnet 17, the stirring plate 15, and the reed switch 20 constitute an embodiment of the remaining powder amount detecting device of the present invention.

  In the powder container 10, a stirring shaft 21 is pivotally supported by the powder container 10 below the support shaft 14, and the stirring shaft 21 has a cam 23. The stirring shaft 21 is driven to rotate by a power source (not shown). The cam 23 is rotated by the rotation of the stirring shaft 21, and the stirring plate 15 is swung around the support shaft 14 as the cam 23 rotates. As the stirring plate 15 swings, the powder 2 in the powder container 10 is stirred.

  In the powder container 10, a supply screw 24 is rotatably disposed in the powder container 10 below the stirring shaft 21. The supply screw 24 is rotationally driven by a power source that rotationally drives the stirring shaft 21. By rotating the supply screw 24, the powder 2 in the powder container 10 is moved into the supply port 7, and the powder 2 is supplied from the supply port 7 into the developing unit 8. It becomes. In FIG. 1, reference numeral 19 denotes a toner density sensor.

  FIG. 4A shows the case where the powder 2 is stored in the powder container 10 up to the level of the reed switch 20, that is, the powder 2 is sufficiently stored in the powder container 10. The powder supply apparatus is shown typically. In this case, when the stirring shaft 21 is rotated to rotate the cam 23 and the stirring plate 15 is swung around the support shaft 14, the swing range of the magnet 17 that swings together with the stirring plate 15 is as described above. It is above the level of the reed switch 20. Therefore, the reed switch 20 is not turned on by the magnetic field from the magnet 17, and the reed switch 20 is not turned on and off, and is always in the off state.

  On the other hand, FIG. 4B shows a case where the powder 2 does not reach the level of the reed switch 20 in the powder container 10, that is, a small amount of the powder 2 is stored in the powder container 10. The powder supply apparatus is shown typically. In this case, when the stirring shaft 21 is rotated to rotate the cam 23 to swing the stirring plate 15 about the support shaft 14, the swing range of the magnet 17 swinging with the stirring plate 15 is as described above. The level of the reed switch 20 has been reached. Therefore, every time the magnet 17 swings and passes through a position near the reed switch 20, the reed switch 20 repeats the on / off operation. It is possible to detect that the amount of the powder 2 stored in the powder container 10 is reduced by a signal generated by the on / off operation of the reed switch 20.

  Here, FIG. 5 schematically shows lines of magnetic force between the iron piece 20A of the reed switch 20 outside the powder container 10 and the magnet 17 facing the iron piece 20A. Here, since the developer of the powder 2 includes the magnetic body 27, the magnetic body 27 is attracted to the magnet 17, but the nonmagnetic sheet 18 attached to the approximate center of the side surface 17 </ b> A of the magnet 17. The amount of adsorption of the magnetic body 27 is small at the location.

  By the way, as shown in the comparative example of FIG. 6B, when the nonmagnetic sheet 18 is not attached to the magnet 17, the magnetic body 27 is attracted to substantially the entire periphery of the magnet 17. In this comparative example, the magnetic body 27 covers substantially the entire periphery of the magnet 17. For this reason, among the lines of magnetic force from the magnet 17, a line of magnetic force that passes through the magnetic body 27 but does not reach the iron piece 20 </ b> A of the reed switch 20 (line of magnetic force that does not go out of the magnetic body 27) is generated. As a result, in the comparative example of FIG. 6B, the magnetic force (the number of lines of magnetic force) reaching the iron piece 20A of the reed switch 20 is reduced compared to the comparative example of FIG. As a result, the energy for operating the reed switch 20 is reduced, and the operation sensitivity of the reed switch 20 is reduced.

  On the other hand, in this embodiment, as shown in FIG. 5, the amount of adsorption of the magnetic body 27 is small at the location of the non-magnetic sheet 18, so that the range of the magnetic body 27 is larger than that of the comparative example of FIG. 6B. There are few lines of magnetic force that form a closed loop, and the magnetic force reaching the reed switch 20 can be increased. Therefore, in this embodiment, the magnetic force almost the same as that in the comparative example of FIG. 6A in which the magnetic material is not attached to the magnet 17 can be made to reach the reed switch 20, which is almost the same as the state in which the magnetic material is not attached. Equivalent sensitivity can be secured. Therefore, according to this embodiment, the nonmagnetic sheet 18 attached to the magnet 17 can prevent the magnetic force that reaches the reed switch 20 from the magnet 17 from being affected by the magnetic body 27 included in the powder 2. . Therefore, the operation sensitivity of the reed switch 20 is not lowered and the remaining amount of powder can be detected correctly.

  In the above embodiment, the adhesion suppressing structure that suppresses the adhesion of the magnetic material to the magnet 17 is a nonmagnetic sheet composed of a nonmagnetic material. However, the screw that fixes the magnet 17 to the stirring plate 15 is made of plastic. A structure in which the head of the screw is extended from the approximate center of the side surface 17A of the magnet 17 to the N extreme and the S extreme may be used as the adhesion suppressing structure. In the above embodiment, the magnetic field detection unit that detects the magnetic field from the magnet 17 is a reed switch.

2 Powder 7 Supply port 8 Developer unit 10 Powder container 10A Side wall 11 Toner bottle 13 Supply port 14 Support shaft 15 Stirring plate 15A Side surface 17 Magnet 17A Side surface 18 Nonmagnetic sheet 20 Reed switch 20A Iron piece 21 Stirring shaft 23 Cam 24 Supply screw 27 Magnetic material

Claims (4)

An oscillating member that is pivotally supported so as to be able to oscillate in a powder container that contains powder containing a magnetic material;
A magnet attached to the rocking member and rocked together with the rocking member and displaced within the rocking range according to the amount of powder stored in the powder container;
The magnetic field incident from the magnet when the magnet is at a predetermined position within the swing range is greater than the magnetic field incident from the magnet when the magnet is not at the predetermined position. A magnetic field detector arranged to be,
An adhesion suppressing structure that is disposed between the N extreme and the S extreme of the magnet and suppresses the adhesion of the magnetic substance contained in the powder to the magnet ;
The powder remaining amount detecting device , wherein the adhesion suppressing structure is provided in a part between the N extreme and the S extreme on the side where the magnet is opposed to the magnetic field detection unit . In the powder residual amount detection apparatus according to claim 1,
The magnetic field detector is
The powder is turned on when the magnet is at a predetermined position within the swing range, and turned off when the magnet is not at a predetermined position within the swing range. A powder remaining amount detecting device, wherein the device is a reed switch arranged outside a body container. In the powder residual amount detection apparatus according to claim 1 or 2,
The adhesion suppression structure is
A powder remaining amount detecting device, which is a nonmagnetic member attached between the N extreme and the S extreme of the magnet. In the powder residual amount detection apparatus according to claim 3,
The non-magnetic member is
The magnet is disposed at substantially the center between the N extreme and the S extreme of the magnet and has a length that is not less than one third and not more than one half of the length between the N extreme and the S extreme of the magnet, and A powder remaining amount detection apparatus, which covers a region of one third or more and one half or less of the region of the magnet on the magnetic field detection unit side.

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