JP5349207B2 - Powder charge meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a work for inserting and extracting a filter cartridge, and a work for preparing a next measurement without the necessity for cleaning attached powder. <P>SOLUTION: A powder charge measuring instrument 1 includes a first outer cover 21, a first inner case 23, a first housing member 2 having a first holder 22 for electrically insulating them, and a second housing member 3 having a second outer cover 51 and a second inner case 53. When both housing members 2, 3 are assembled, a relative dielectric constant is 8.0 or more and 3.0 or less on a surface other than a portion contacting at least both inner containers on at least one surface in an insulating material portion among regions in which both housing members 2, 3 face each other. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a powder that sucks charged powder such as toner in electrophotographic technology, which is a measurement sample, and charged powder paint in electrostatic powder coating technology, and measures the charge amount of the sucked powder. The present invention relates to a body charge measuring device.

  As a conventional powder charge amount measuring device, for example, Patent Document 1 includes an insulating container and a conductor container housed in the insulating container, and a filter that captures toner inside the conductor container is a conductor container. A powder charge amount measuring device that measures the charge amount of toner in a suction nozzle, which is a conductor container, having a structure sandwiched between an intake port portion and an exhaust port portion constituting a suction nozzle is described. In this powder charge amount measuring device, the charge amount of the toner sucked into the suction nozzle in the insulating container is measured. Then, the lid of the insulating container is removed, the suction nozzle is taken out from the insulating container, and the weight of the suction nozzle containing the toner is measured. By dividing the difference between the measured weight and the previously measured weight of the suction nozzle by the measured charge amount, the charge amount per unit weight of the toner can be obtained.

Japanese Patent No. 3567463 (FIG. 5)

  In the powder charge measuring device described in Patent Document 1, it is necessary to remove the lid of the insulating container in order to measure the weight of the suction nozzle. There is no specific description in Patent Document 1 regarding the structure for attaching the lid to the insulating container. If the lid is firmly fixed to the insulating container with a plurality of screws or the like, the operation for putting the suction nozzle in and out of the insulating container becomes very complicated. In the next measurement, it is necessary to disassemble the suction nozzle and clean the inside of the suction nozzle to which the toner has adhered, and further complicated work such as replacement of the filter in the suction nozzle requires a long preparation for the measurement work. There was a problem such as.

  Therefore, an object of the present invention is to measure the amount of electric charge of the powder that simplifies the work of putting in and out the filter cartridge, does not require cleaning of the adhered powder, and simplifies the preparation work for the next measurement. Is to provide a vessel.

Means for Solving the Problems and Effects of the Invention

The powder charge measuring device of the present invention has a housing for storing a filter cartridge in which a filter for capturing powder sucked from the outside is stored, and the charge amount of the powder captured in the filter cartridge in the powder charge amount measuring device for measuring, the housing has first and second housing members forming a space for accommodating the filter cartridge by detachably engaged with each other, wherein The first housing member includes an outer first cover made of a conductive material, an inner first case made of a conductive material housed in the outer first cover, and between the outer first cover and the inner first case. And the second housing member is formed of a conductive material that can be fitted so as to partially cover the outer first cover. And an inner second case made of a conductive material housed in the outer second cover and electrically insulated from the outer second cover, and the insulator is a fitting region where both housing members overlap each other The outer first cover has an outer diameter smaller than the outermost diameter, and is separated from the inner peripheral surface of the outer second cover .

  According to this, since the housing has a two-divided structure in which the housing can be fitted, the operation of inserting and removing the filter cartridge is simplified. In addition, at the time of the next measurement, it is only necessary to replace the filter cartridge with a new one, and there is no need to disassemble and clean the suction nozzle portion or the like as in the prior art, and the workability of the measurement is improved. Further, when the two housing members are fitted together, the insulator and the outer second cover are less likely to come into contact with each other, and electric charges due to friction are less likely to occur. Therefore, it becomes difficult to affect the measurement of the charge amount.

In another aspect, the powder charge measuring device of the present invention has a housing for storing a filter cartridge in which a filter for capturing powder sucked from the outside is stored, and is captured in the filter cartridge. in the powder charge amount measuring device for measuring the amount of charge by powders, the housing, the first and the second forming a space for accommodating the filter cartridge by detachably engaged with each other The first housing member includes an outer first cover made of a conductive material, an inner first case made of a conductive material housed in the outer first cover, the outer first cover, and the and a electrically insulating insulator both disposed between the first inner casing, said second housing member includes a second outer cover consisting of conductive material, the outer second cover Osamu Is and a second inner case made of outer second cover and electrically insulated conductive material, the insulating body, Te opposite region odor both housing members are opposed to each other, said second housing member We are separated.

According to this, since the housing has a two- part structure, the work for inserting and removing the filter cartridge is simplified. In addition, at the time of the next measurement, it is only necessary to replace the filter cartridge with a new one, and there is no need to disassemble and clean the suction nozzle portion or the like as in the prior art, and the workability of the measurement is improved. Further, when both housing members are assembled , the insulator and the outer second cover are less likely to come into contact with each other , and electric charges due to friction are less likely to occur. Therefore, it becomes difficult to affect the measurement of the charge amount.

In the present invention, it is preferable that the insulator has a relative dielectric constant of 3.0 or less at least on a surface facing the second housing member . Thereby, even if an insulator and a 2nd housing member contact, it becomes difficult to produce the electric charge by friction.

In the present invention, the insulator has a conductivity imparted to at least a surface facing the second housing member, and the conductivity imparting portion is electrically connected to the outer first cover. preferable. As a result, since conductivity is imparted to the surface of the insulator, the electric charge generated by the friction moves to the grounded first outer cover, and it is difficult to affect the measurement of the electric charge amount.

In another aspect, the powder charge measuring device of the present invention has a housing for storing a filter cartridge in which a filter for capturing powder sucked from the outside is stored, and is captured in the filter cartridge. In the powder charge amount measuring device for measuring the charge amount of the powder thus formed, the housing forms a space for housing the filter cartridge by being separably engaged with each other. The first housing member includes an outer first cover made of a conductive material, an inner first case made of a conductive material housed in the outer first cover, the outer first cover, and the The second housing member is disposed between the inner first case and the outer second cover made of a conductive material; and the second housing member is accommodated in the outer second cover. And an inner second case made of a conductive material electrically insulated from the outer second cover, wherein the insulator has a relative dielectric constant of 3.0 at least on a surface facing the second housing member. It is as follows .
According to this, since the housing has a two-part structure, the work for inserting and removing the filter cartridge is simplified. In addition, at the time of the next measurement, it is only necessary to replace the filter cartridge with a new one, and there is no need to disassemble and clean the suction nozzle portion or the like as in the prior art, and the workability of the measurement is improved. In addition, when the two housing members are assembled, even if the insulator comes into contact in the region where the two housing members face each other and a charge is generated due to friction at the contact portion, the measurement of the charge amount is hardly affected. That is, when the relative dielectric constant of the surface is 3.0 or less, the charge amount of the charge generated by friction is extremely small, and it is difficult to affect the measurement of the charge amount. Therefore, the measurement accuracy of the charge amount by the powder charge meter is improved.

In another aspect, the powder charge measuring device of the present invention has a housing for storing a filter cartridge in which a filter for capturing powder sucked from the outside is stored, and is captured in the filter cartridge. In the powder charge amount measuring device for measuring the charge amount of the powder thus formed, the housing forms a space for housing the filter cartridge by being separably engaged with each other. The first housing member includes an outer first cover made of a conductive material, an inner first case made of a conductive material housed in the outer first cover, the outer first cover, and the The second housing member is disposed between the inner first case and the outer second cover made of a conductive material; and the second housing member is accommodated in the outer second cover. And an inner second case made of a conductive material that is electrically insulated from the outer second cover, and the insulator has conductivity imparted to at least a surface facing the second housing member. The conductivity imparting portion is electrically connected to the outer first cover .
According to this, since the housing has a two-part structure, the work for inserting and removing the filter cartridge is simplified. In addition, at the time of the next measurement, it is only necessary to replace the filter cartridge with a new one, and there is no need to disassemble and clean the suction nozzle portion or the like as in the prior art, and the workability of the measurement is improved. In addition, when the two housing members are assembled, even if the insulator comes into contact in the region where the two housing members face each other and a charge is generated due to friction at the contact portion, the measurement of the charge amount is hardly affected. That is, since conductivity is imparted to the surface of the insulator, the electric charge generated by friction moves to the grounded outer first cover, and it is difficult to affect the measurement of the electric charge amount.

Further, in the present invention, the insulator is a dielectric constant preferably Rukoto such from 3.0 following polytetrafluoroethylene or polycarbonate. In the present invention, the conductivity imparting portion is preferably composed of a conductive film made of a material having a relative dielectric constant of 8.0 or more. Further, in the present invention, by assembling both housing members, both the outer covers and the inner cases are engaged and electrically connected to each other, and the space is formed between the inner cases. preferable.

Further, in the present invention, the insulator supports the inner first case in a slidable manner, and the inner member is in the state where both housing members are assembled between the insulator and the inner first case. It is preferable that a biasing member that biases the inner first case toward the inner second case is disposed so that the two cases are pressed against each other . Thereby, since the press contact force of the inner first case and the inner second case is increased, the electrical connection state between the two is further ensured. Furthermore, even if there is rattling between the outer both covers, it is possible to absorb the rattling and suppress a decrease in pressure contact force between the inner first case and the inner second case.

In the present invention, a biasing member that biases the filter cartridge toward the inner second case in a state where both housing members are assembled is disposed in the inner first case. preferable. Thereby, the powder can be reliably sucked and collected in the filter cartridge, and the powder is not accidentally sucked into the gap between the inner first case and the filter cartridge.

It is a schematic diagram when the 1st housing member and 2nd housing member of the powder electric charge measuring device by 1st Embodiment of this invention are isolate | separated. It is a perspective view when the 1st housing member and 2nd housing member of the powder charge amount measuring device by a 2nd embodiment of the present invention are made to separate. FIG. 3 is an exploded perspective view of the powder charge measuring device shown in FIG. 2. It is sectional drawing of the powder charge amount measuring device by one Embodiment of this invention. FIG. 4 is a sectional view taken along line IV-IV shown in FIG. 3. FIG. 3 is a perspective view of an outer second cover shown in FIG. 2, showing a state where a protrusion forming member is removed from the cover. FIG. 4 is a perspective view of the filter cartridge shown in FIG. 3. FIG. 4 is a cross-sectional view of the filter cartridge shown in FIG. 3. It is sectional drawing when a filter cartridge is assembled | attached to the 1st and 2nd housing member. It is a schematic sectional view showing the state of the charge generated in the filter cartridge and the charge generated by friction when assembling both housing members when measuring the charge amount of the powder sucked using the powder charge amount measuring device. The 1st modification of the powder electric charge measuring device by 2nd Embodiment of this invention is shown, (a) is sectional drawing of an outer side 1st cover, (b) is sectional drawing of a 1st holder, c) is a cross-sectional view of the outer second cover. It is sectional drawing of what showed the 2nd modification of the powder electric charge measuring device by 2nd Embodiment of this invention, and the 1st holder was fixed to the outer side 1st cover. It is sectional drawing of the thing with which the 3rd modification of the powder charge amount measuring device by 2nd Embodiment of this invention was shown, and the 1st holder was fixed to the outer side 1st cover.

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

[First Embodiment]
As shown in FIG. 1, the powder charge amount measuring device 1 includes a housing 1a, a filter cartridge 4 housed in the housing 1a, and a filter unit 5. The housing 1a includes a first housing member 2 and a second housing member 3, and is configured to be separable. The filter cartridge 4 is accommodated in a space formed when these housing members 2 and 3 are assembled. The housing 1a is provided with a connecting member 70 for connecting the piping member 6 connected to a suction pump (not shown) to the housing 1a. The filter unit 5 is provided in the middle of the piping member 6. For this reason, the powder charge measuring device 1 is driven from the outside in the direction parallel to the axial direction from the left to the right in FIG. 1 (suction direction A) by driving the suction pump. The powder charged with the gas is sucked. In addition, the gas discharged from the housing 1 a by this suction (the gas sucked into the housing 1 a from the outside) flows to the suction pump side through the hole 70 a of the connection member 70, the piping member 6 and the filter unit 5. . That is, the connection unit 70, the piping member 6, and the filter unit 5 provided in the middle of the piping member 6 constitute a part of the gas discharge path.

  The first housing member 2 has an outer first cover 21 made of an aluminum alloy, a first holder (insulator) 22 having a relative dielectric constant of 3.0 or less, and an inner first case 23 made of stainless steel. doing. The inner first case 23 is disposed at a position sandwiching the first holder 22 between the outer first cover 21 and the outer first cover 21 and the inner first case 23 are electrically insulated. Is arranged. The outer first cover 21 may be made of aluminum, or any other metal, an alloy made of the metal, or a conductive material. The inner first case 23 may be made of a conductive material other than stainless steel. The cylindrical first holder (insulator) 22 may be anything as long as it has insulating properties, but desirably has a relative dielectric constant of 3.0 or less, such as polytetrafluoroethylene or polycarbonate.

  An annular flange 31 having a hole 31a through which a part of the first holder 22 and the inner first case 23 can be inserted is formed at the upstream end of the outer first cover 21 in the suction direction A.

  The second housing member 3 includes an outer second cover 51 made of an aluminum alloy that partially covers the outer first cover 21, a second holder 52, and an outer second cover 51 made of stainless steel. An inner second case 53 disposed at a position sandwiching the second holder 52; and a joint holder 54 disposed at a position sandwiching the outer second cover 51 between the second holder 52 and the outer second case 52. The two cover 51 and the inner second case 53 are arranged in a state where they are electrically insulated by the second holder 52. The outer second cover 51 may be made of aluminum, like the outer first cover 21, or any other metal, an alloy made of the metal, or a conductive material. The inner second case 53 may be made of a conductive material other than stainless steel. The second holder (insulator) 52 may be anything as long as it has insulating properties, but it is desirable that the relative permittivity is 3.0 or less, such as polytetrafluoroethylene or polycarbonate.

  An annular flange 61 having a hole 61a through which a part of the second holder 52 can be inserted is formed at the downstream end of the outer second cover 51 in the suction direction A. The annular flange 61 is formed with a hole 61b through which a coaxial cable connected to a measurement electrometer (not shown) is passed. The outer shield wire of the coaxial cable is connected to the outer second cover 51, and the core wire Is connected to the inner second case 53. That is, the outer second cover 51 is grounded.

  The filter unit 5 is provided outside the housing 1 a via the connection member 70 and the piping member 6. The filter unit 5 includes a cylindrical resin case 7 and a filter member 8 accommodated in the resin case 7. The resin case 7 has a transparent cylindrical main body portion 7a and connection portions 7b that connect the pipe member 6 to both ends of the main body portion 7a. The connection part 7b is configured in a one-touch manner in which the piping member 6 can be freely attached and detached. Thereby, attachment / detachment with respect to the piping member 6 of the filter unit 5 becomes easy.

  The filter member 8 is accommodated in the main body 7a. Thus, it can be seen at a glance whether or not the filter unit 5 has collected the powder by accommodating the filter member 8 in the main body portion 7a, which is a transparent region. Therefore, it is possible to confirm whether the filter 83 (described later) is broken or forgotten to be mounted. The filter member 8 is a hollow fiber membrane filter and is provided with a higher filtration accuracy than the filter 83 housed in the filter cartridge 4. That is, for example, when a filter paper having a particle retention capacity of 1.0 μm or 0.7 μm is used as the filter 83, a hollow fiber membrane filter having a filtration accuracy of 0.01 μm is provided as the filter member 8.

  Next, the filter cartridge 4 will be described below with reference to FIGS. As shown in FIGS. 7 and 8, the filter cartridge 4 includes two housings 81 and 82 that can be fitted to each other, and a filter 83 that is housed in both the housings 81 and 82. These two housings 81 and 82 are fitted to form one container.

  The two housings 81 and 82 are made of polypropylene resin to which metal fine powder, which is a conductive material, is added, and have overall conductivity. Since the container of the filter cartridge 4 is made of a synthetic resin to which a conductive material is added, the weight can be reduced to about 2 to 3 g. That is, the filter cartridge 4 can be made closer to the weight of the powder to be sucked. If the filter cartridge is made of metal, the weight increases to about 100 g. Then, in order to accurately measure the total weight of the powder collected by the filter cartridge and the filter cartridge, if the weighing range of the electronic balance is set to 0.01 mg, for example, the total weight is too large. become unable. If the weighing range is increased in order to measure the total weight of the filter cartridge and the powder, the accuracy of the measured weight is lowered. However, since the weight of the filter cartridge 4 can be reduced to about 2-3 g, the total weight of the filter cartridge 4 and the powder can be measured even if the weighing range is 0.01 mg. It becomes.

  In the present embodiment, metal fine powder and polypropylene resin are adopted as the material constituting the housings 81 and 82. However, a conductive material other than the metal fine powder, such as metal, is used as long as it has conductivity. The fiber or carbon black, and the constituent resin may be a synthetic resin other than polypropylene resin, such as polyethylene resin or styrene resin.

Generally, the surface conductivity of the synthetic resin is 10 ⁻¹⁴ Scm ² or less. In this embodiment, it is preferable to add 10 ⁻¹¹ Scm ² or more by adding a conductive material to the synthetic resin. More preferably, it is 10 ⁻⁹ Scm ² or more.

  Moreover, it is preferable that the synthetic resin and additive material of both the housings 81 and 82 in this embodiment have transparency to the extent that the internal state can be seen from the outside. Furthermore, the amount of the conductive material added to the synthetic resin is preferably such that it has an appropriate surface conductivity and can ensure transparency to the extent that the internal state can be seen from the outside. As a result, it is possible to check whether the filter cartridge 4 is a used filter cartridge 4 in which powder is sucked into the filter cartridge 4, and it is also possible to check the storage state of the filter 83 in the filter cartridge 4. . Further, it is sufficient that at least one or both of the housings 81 and 82 have transparency. Also in this case, the same effect as described above can be obtained.

  The filter cartridge 4 includes a cylindrical elongated portion 4a extending along the suction direction A, a cylindrical enlarged portion 4b having a diameter larger than the inner diameter of the downstream end of the elongated portion 4a, and a long length. It has a cylindrical short part 4c shorter than the part 4a. The filter 83 is a filter paper type filter having a disk shape, and is selected according to the particle size of the powder to be measured. For example, when measuring the charge amount of toner in the electrophotographic technique, the particle retention ability Is used. When measuring the charge amount of finer powder, for example, a filter paper having a particle holding capacity of 0.7 μm is used.

  Next, an operation until obtaining the charge amount per unit weight of the powder sucked using the powder charge measuring device 1 will be described with reference to the drawings.

  First, the user measures the weight of the filter cartridge 4 alone with an electronic balance. Then, as shown in FIG. 1, the user places the filter cartridge 4 between the separated first and second housing members 2, 3, and the elongated portion 4 a of the filter cartridge 4 is placed inside the first case. 23 is inserted. Thereafter, the separated first and second housing members 2 and 3 are assembled. As an assembling method, for example, the first and second housing members 2 and 3 separated by attaching a hook to the second housing member 3 are coupled, or a coupler is attached to the second housing member 3. What is necessary is just to combine 2 and 3. At this time, both the outer covers 21, 51 and the inner covers 23, 53 are engaged with each other, and are electrically connected to each other. At this time, the filter cartridge 4 and the inner second case 53 are in direct contact and are electrically connected. Since the outer covers 21 and 51 are engaged with each other, the influence of the external electric field can be effectively eliminated when measuring the charge amount in the inner first and second cases 23 and 53.

  In assembling the separated first and second housing members 2 and 3, if the first holder 22 and the second holder 52 come into contact with each other and friction occurs, friction occurs at the interface between the first holder 22 and the second holder 52. Charge is generated. When assembling the separated first and second housing members 2 and 3, when the first holder 22 and the second holder 52 are not in direct contact and the interface between both the holders 22 and 52 is filled with air, Since both the holders 22 and 52 are not in direct contact with each other and do not rub, the frictional charge is extremely difficult to be generated. For this reason, the charge amount in the inner first and second cases 23 and 53 can be accurately measured. It should be noted that the interface between the holders 22 and 52 may be any gas as long as it is not air. In this case, when assembling the separated first and second housing members 2 and 3, the holders 22 and 52 come into contact with and rub against a gas such as air. However, the value of the relative dielectric constant of a gas containing air is approximated by 1 and is extremely low, so that triboelectric charge is hardly generated.

  Even if the first holder 22 and the second holder 52 are in direct contact with each other and friction occurs, if both the holders 22 and 52 are made of polytetrafluoroethylene or polycarbonate having a very low relative dielectric constant, Electric charges are less likely to occur.

  Next, the user drives the suction pump to generate a suction force at the suction port 86a of the filter cartridge 4 incorporated in the powder charge measuring device 1, and sucks the powder together with gas from the outside into the filter cartridge 4. . At this time, the sucked powder is captured by the filter 83, and the gas is discharged from the discharge port 98 to the suction pump side through the discharge path (hole 70a, piping member 6 and filter unit 5). If the filter 83 of the filter cartridge 4 is damaged or not properly attached, or if the filter 83 is damaged during the operation of the suction pump, the sucked powder passes through the filter cartridge 4 and passes through the suction pump. Although the filter unit 5 is provided in the discharge path, the powder is collected by the filter member 8 of the filter unit 5 and is not discharged to the suction pump side. For this reason, it is possible to reliably prevent the danger that the sucked powder is scattered from the suction pump to the outside. Moreover, since the main-body part 7a of the filter unit 5 is transparent at this time, it can be known at a glance whether the powder was collected by the filter unit 5 or not. In addition, when powder is collected by the filter unit 5, it replaces | exchanges for the filter cartridge 4 without a malfunction, and attracts | sucks powder again.

  Next, the drive of the suction pump is stopped, and when the powder is not collected in the filter unit 5, the total charge amount of the powder in the filter cartridge 4 is measured. Here, as described above, the frictional charge generated when the two housing members 2 and 3 are assembled is generated at the interface between the first holder 22 and the second holder 52. However, in this embodiment, the charge generated by friction is very small. Charges E0a and E0b equivalent to these charges are transferred to the capacitor C formed between the inner first and second cases 23 and 53 and the outer first and second covers 21 and 51 (ground in the drawing). Occurs (see FIG. 10). As described above, since the charges E0a and E0b generated in the capacitor C are extremely small, the measurement of the charge amount of the powder in the filter cartridge 4 described later hardly affects. As a result, the amount of charge in the inner first and second cases 23 and 53 can be accurately measured.

As shown in FIG. 10, the filter cartridge 4 has an equal amount of opposite polarity by electrostatic induction in accordance with the amount of charge E1 (for example, negative charge) of the powder collected in the filter cartridge 4. A charge E2 (positive charge) is generated. At this time, at the time of sucking the powder, the powder is frictionally charged on the inner wall of the filter cartridge 4, and charges E3a and E3b (for example, negative charges) are applied to the inner surface of the filter cartridge 4, and charges E4a and E4b are applied to the powder. (Positive charge) is generated. Of these, as shown in FIG. 10, the electric charges E3a and E4a are closed by electric lines of force (arrows indicated by broken lines in FIG. 10) to form a pair, and are not closed by electric lines of force and are substantially paired. There are no charges E3b and E4b. It is considered that the powder having the latter charge E4b is separated from the place where the charge E3b exists on the inner wall of the filter cartridge 4 due to the movement in the cartridge. Then, according to the charge amounts of these two charges E3b and E4b, charges E5b and E6b having the same opposite polarity are generated in the filter cartridge 4 by electrostatic induction. The charges E2, E5b, E6b generated on the inner wall of the filter cartridge 4 have the same amount of charge as the inner first and second cases 23, 53 and the outer first, second cover 21 of the powder charge measuring device 1. , 51 (grounded in the figure). On the other hand, since the two charges E5b and E6b are equal and have opposite polarities, they are canceled each other. By measuring a charge amount equal to the charge E2 generated in the capacitor C, the charge E1 of the powder collected in the filter cartridge 4 can be measured.
From the above measurement principle, it is influenced by the charges E0a, E0b, E3a, E3b, E4a, and E4b applied by frictional charging when the housing members 2 and 3 are fitted and frictional charging when the powder is attracted. Therefore, the original charge amount E1 of the powder can be measured.

  Next, when the user measures the total weight of the filter cartridge 4 and the powder with an electronic balance and divides the total charge amount of the powder by the total weight of the powder, the charge per unit weight of the powder The amount can be determined.

In the embodiment described so far, the two housings 81 and 82 are described as being made of a synthetic resin to which a conductive material is added. However, the two housings 81 and 82 are made of a synthetic resin to which a conductive material is not added. A conductive film applied by spraying or the like may be formed on the entire outer surfaces of the two housings 81 and 82. The conductive film is made of conductive fine particles such as metal fine powder mixed in a binder material, but may be any material as long as it has conductivity. As described above, the surface conductivity is preferably 10 ⁻¹¹ Scm ² or more, and more preferably 10 ⁻⁹ Scm ² or more.
When conductivity is imparted like the filter cartridge described above, the electric force lines of electric charge inside the filter cartridge can be confined, and the influence of the electric lines of force to the outside of the filter cartridge can be eliminated to perform accurate weight measurement. Has the advantage of being able to do it.

  Further, the two housings 81 and 82 may be made of an insulating synthetic resin to which no conductive material is added. A filter cartridge made of an insulating synthetic resin is considered to cause measurement errors due to frictional charging between the sucked toner and the filter cartridge 4 made of an insulating material when sucking toner or the like. However, even if charge is generated by frictional charging, positive and negative equivalent charges are canceled and the actual charge amount measurement is not affected. The filter cartridge 4 made of an insulating synthetic resin does not have the advantage of confining the electric field lines of electric charges inside the filter cartridge, but it is possible to add a conductive material to the synthetic resin or apply it to the outer surface of the synthetic resin by spraying. It is provided at low cost.

  As described above, according to the present embodiment, since the housing 1a has a two-divided structure that can be assembled, the operation of inserting and removing the filter cartridge 4 is simplified. In addition, at the time of the next measurement, it is only necessary to replace the filter cartridge 4 with a new one, and there is no need to disassemble and clean the suction nozzle portion or the like as in the prior art, improving the workability of the measurement. Further, since the amount of frictional charge generated when the two housing members 2 and 3 are assembled is reduced, measurement of the amount of charge of the powder in the filter cartridge 4 is hardly affected.

As a modification of the first embodiment, when the two housing members 2 and 3 are assembled, the surfaces of the first holder 22 and the second holder 52 in the region where the two housing members face each other are applied by spraying or the like. The conductive film 201 may be partially formed. In the present embodiment, FC-172 fine ESD coat manufactured by Fine Chemical Japan Co., Ltd. is employed for these conductive films 201. However, if the relative dielectric constant is 8.0 or more, a conductor such as metal is used. Any material may be used, such as plating or metal foil formed in (1). In general, a material having a high relative dielectric constant tends to have a high electrical conductivity. When the relative dielectric constant is 8.0 or more, the conductivity is sufficiently high, and the electric charge generated by the friction moves to the outer first cover 21 and the outer second cover 51. As a result, the electric charge generated by the friction flows to the ground, As a result, it becomes difficult to affect the measurement of the charge amount. For example, when a part of the conductive film 201 is electrically connected to the outer first cover 21 and the outer second cover 51, the charge generated by friction moves to the outer first cover 21 and the outer second cover 51. Finally, it escapes to the ground through the outer shield line of the coaxial cable connected to the outer second cover 51.
In the case where the conductive film 201 is partially formed on the surfaces of the first holder 22 and the second holder 52, the first holder 22 and the second holder 52 are low dielectric constant materials as long as they have insulating properties. It doesn't have to be anything.

When the outer first cover 21 is made of an aluminum alloy, the entire surface of the outer first cover 21 is anodized on the entire surface, that is, the aluminum alloy that is the base material of the outer first cover 21. A hard coating 10 that is harder and has insulating properties may be formed. In addition, the hard coating 15 having insulating properties formed by anodizing may be formed on the entire surface of the outer second cover 51. If the hard coating is formed in this way, it is possible to suppress the occurrence of scraping or galling due to rubbing between the covers when both covers are assembled.
In addition, when the hard coating 15 which has insulation is formed, both the covers 21 and 51 are electrically connected, and the influence of the external electric field in the measurement of the charge amount in the inner first and second cases is effectively eliminated. In order to achieve this, it is necessary to electrically join a part of both covers 21 and 51. For example, when the housings 2 and 3 are assembled, a conductive film is formed on the surface of the hard coating 15 in a region where the covers 21 and 51 are in contact, and the covers 21 and 51 are electrically connected. What is necessary is just to connect the outer shield line of a coaxial cable.

[Second Embodiment]
Next, the second embodiment will be described.

In this embodiment, the assembly of the separated first and second housing members 2 and 3 is made stronger than in the first embodiment. Specifically, the two housing members 2 and 3 are fitted to each other, so that the assembly is strengthened, and both the housing members 2 and 2 can be easily used during the measurement of the powder charge amount or the handling of the powder charge amount measuring device 1. 3 was not removed, and the convenience of measurement or handling was made.
A powder charge measuring device 1 is shown in FIG. 2 and has a structure similar to that shown in FIG. The difference between FIG. 2 and FIG. 1 will be described below. The outer shape of the housing 1a has a substantially cylindrical shape (in the first embodiment, a shape other than a cylinder may be used). The housing 1a has a first housing member 2 and a second housing member 3 and is configured to be separable. At the same time, the housing members 2 and 3 are firmly assembled by fitting. It has been. The filter cartridge 4 is accommodated in a space formed when these housing members 2 and 3 are fitted.

  As shown in FIGS. 3 and 4, the first housing member 2 includes a cylindrical outer first cover 21 made of aluminum alloy and a cylindrical first cover made of polytetrafluoroethylene having a relative dielectric constant of 2.1. One holder (insulator) 22 and a cylindrical inner first case 23 made of stainless steel are provided. The inner first case 23 is disposed at a position sandwiching the first holder 22 between the outer first cover 21 and the outer first cover 21 and the inner first case 23 are electrically insulated. Is arranged. The outer first cover 21 may be made of aluminum. The inner first case 23 may be made of a conductive material other than stainless steel.

  At the upstream end of the outer first cover 21 in the suction direction A, an annular flange 31 having a hole 31a through which a part of the first holder 22 and the inner first case 23 can be inserted is formed as in the first embodiment. ing. At the downstream end in the suction direction A of the outer first cover 21, an annular protrusion 33 is formed which is formed by forming a groove 32 extending in the circumferential direction in the vicinity of the downstream end. Two cutouts 34 a and 34 b are formed in the annular protrusion 33. The notch 34a is formed at a position rotated 180 ° from the notch 34b. That is, the two notches 34 a and 34 b are arranged symmetrically with respect to the central axis of the outer first cover 21. As shown in FIG. 4, the annular protrusion 33 protrudes from the outer peripheral surface of the outer first cover 21 in a fitting region that overlaps with each other when the housing members 2 and 3 are fitted together.

  Further, the entire surface of the outer first cover 21 has an anodic oxide coating formed by anodizing, that is, a hard coating 10 that is harder and more insulative than the aluminum alloy that is the base material of the outer first cover 21. Is formed.

  The thickness of the hard coating 10 in the present embodiment is about 30 μm, but may be any thickness as long as it is in the range of 10 μm to 100 μm. That is, if the thickness of the hard coating 10 is 10 μm or more, the entire surface of the outer first cover 21 can be made harder than the base material, and if it is 100 μm or less, the hard coating 10 can be manufactured. Become.

  Further, as shown in FIG. 5, two contact regions 11 where the hard coating 10 is not formed are formed on the surface 33 a on the groove 32 side of the annular protrusion 33 of the outer first cover 21. These two contact areas 11 are arranged symmetrically with respect to the central axis of the outer first cover 21. The two contact areas 11 are arranged at positions rotated by 90 ° from the notches 34a and 34b. Further, the two contact regions 11 are disposed at positions where they can come into contact with projection forming members 66 and 67 described later when the two housing members 2 and 3 are assembled.

  The contact region 11 in this embodiment is configured by forming the hard coating 10 on the entire surface of the outer first cover 21 except for the contact region 11 in a state where only the region 11 is masked. That is, the contact region 11 is the surface of the base material of the outer first cover 21 before the alumite treatment. In addition, after forming the hard film 10 in the whole surface of the outer side 1st cover 21, the contact area 11 cuts only the part used as the said contact area 11, and is the base material of the outer side 1st cover 21 before anodizing processing. It may be formed by exposing the surface.

  As shown in FIGS. 3 and 4, the first holder 22 includes a cylindrical tip 22 a that protrudes to the outside from the hole 31 a, a cylindrical main body 22 b that is covered by the outer first cover 21, and a tip 22 a. And an annular flange 22c that connects the main body 22b. As shown in FIG. 4, the first holder 22 has an outer first cover 21 in a state where the annular flanges 31 and 22 c are in close contact with each other by screwing screws in from the outside of the annular flange 31 along the fitting direction. It is fixed to.

  At the downstream end of the main body portion 22b in the suction direction A, an annular protrusion 36 protruding in the radial direction of the main body portion 22b (a direction orthogonal to the fitting direction) is formed. When the first holder 22 is fixed to the outer first cover 21, the annular protrusion (opposing portion) 36 is aligned with the annular protrusion 33 along the fitting direction, and both the housing members 2 and 3 are fitted. At the position facing the outer second cover 51. The outer diameter of the annular protrusion 36 is substantially the same as the outer diameter of the annular protrusion 33. The annular protrusion 36 is formed with two notches 37a and 37b having the same shape and the same size as the two notches 34a and 34b. These notches 37a and 37b are arranged such that when the first holder 22 is fixed to the outer first cover 21, the notches 37a are just opposite to the notches 34a, and the notches 37b are just opposite to the notches 34b. And two large notches 38a and 38b are formed.

  As shown in FIGS. 3 and 4, the inner first case 23 has a long portion 23 a extending along the suction direction A, and a diameter expanded larger than the inner diameter of the downstream end of the long portion 23 a. It has the part 23b and the cylindrical color | collar 45 arrange | positioned in the enlarged diameter part 23b. The elongated portion 23a has a tip portion 41a that protrudes outward from the first holder 22 when the inner first case 23 is attached to the first holder 22, and a diameter that is gradually increased along the suction direction A. It has the connection part 41b which connects 41a and the enlarged diameter part 23b. The inner first case 23 is attached so as not to drop off from the first holder 22 by being provided with a C-type retaining ring 42 after being passed through the first holder 22. Moreover, although the short tube 99 which consists of an insulating material and has flexibility is engage | inserted by the front-end | tip part 41a, it does not need to be provided in particular.

  The diameter-expanded portion 23b is expanded in steps along the suction direction A. A tapered surface 45 a that is inclined with respect to the suction direction A is formed on the inner peripheral surface of the collar 45. The collar 45 is fixed to the enlarged diameter portion 23b with screws in a state of being in close contact with an annular flange 43 formed at the upstream end of the enlarged diameter portion 23b in the suction direction A. The collar 45 is made of brass, which is a conductive material, but may be made of a conductive material other than brass.

  An urging member 47 is disposed in the connecting portion 41b. The biasing member 47 is disposed between the stepped portion 48 of the connecting portion 41b and the collar 45, and the filter cartridge 4 inserted into the inner first case 23 is sucked in the suction direction A (that is, the filter cartridge 4 Urging in the direction away from the inner first case 23). The urging member 47 includes a coil spring 47a and a pedestal 47b disposed between the coil spring 47a and the collar 45. For example, the urging member 47 may be configured by replacing the coil spring 47a with an elastic member such as rubber. The base 47b may be omitted.

  A biasing member 49 is disposed in the main body 22 b of the first holder 22. The biasing member 49 is disposed between the annular flange 22c and the enlarged diameter portion 23b, and biases the inner first case 23 inserted into the first holder 22 in the suction direction A. Since the inner first case 23 is provided with the C-type retaining ring 42, the inner first case 23 does not drop out of the first holder 22 and the first holder 22 in the suction direction A. Is slidably supported. The urging member 49 is composed of a coil spring, but may be composed of an elastic member such as rubber, for example.

  As shown in FIGS. 3 and 4, the second housing member 3 includes a cylindrical outer second cover 51 made of an aluminum alloy that can be fitted so as to partially cover the outer first cover 21, and a polycarbonate resin. A cylindrical inner second case 53 disposed at a position sandwiching the second holder 52 between the second holder 52 made of stainless steel and the outer second cover 51 made of stainless steel, and the second holder 52 made of polycarbonate resin. Between the outer second cover 51 and the outer second cover 51, and the outer second cover 51 and the inner second case 53 are electrically insulated from each other. Yes. Note that the outer second cover 51 may be made of aluminum in the same manner as the outer first cover 21. The inner second case 53 may be made of a conductive material other than stainless steel. The second holder 52 and the joint holder 54 may be made of an insulating material other than polycarbonate resin.

  At the downstream end of the outer second cover 51 in the suction direction A, an annular flange 61 having a hole 61a into which a part of the second holder 52 can be inserted is formed as in the first embodiment. The annular flange 61 is formed with a hole 61b through which a coaxial cable connected to a measurement electrometer (not shown) is passed. The outer shield wire of the coaxial cable is connected to the outer second cover 51, and the core wire Is connected to the inner second case 53. That is, the outer second cover 51 is grounded.

As shown in FIG. 5, the outer second cover 51 has two protrusions 51 a and 51 b that protrude from the inner peripheral surface at the upstream end in the suction direction A. These protrusions 51 a and 51 b are constituted by two protrusion forming members 66 and 67 fixed to the base material of the outer second cover 51. The protrusion forming members 66 and 67 are made of a conductive material such as stainless steel. Specifically, at the upstream end of the outer second cover 51, two notches 68 and 69 are formed as shown in FIG. These notches 68 and 69 are arranged point-symmetrically around the central axis of the outer second cover 51. Then, as shown in FIG. 4, the protrusion forming members 66 and 67 are fitted into the notches 68 and 69 so that the front end portions (projections 51 a and 51 b) protrude from the inner peripheral surface of the outer second cover 51. It is fixed to the outer second cover 51 with screws. The shape of the part which protruded from the internal peripheral surface of the outer side 2nd cover 51 of the protrusion formation parts 66 and 67 is a shape corresponding to the notch parts 38a and 38b. Therefore, after the two outer first and second covers 21 and 51 are fitted together, the first housing member 2 is rotated by 90 ° along the circumferential direction, so that the protrusions are projected in the fitting direction parallel to the suction direction A. 51a and 51b and the annular protrusion 33 engage, and both are assembled | attached. By this engagement, both the housings 2 and 3 are assembled more firmly than in the first embodiment.
However, on the other hand, it is necessary to perform an operation of rotating the first housing member 2 by 90 ° along the circumferential direction after the two outer first and second covers 21 and 51 are fitted before being engaged. For this reason, the distance that the first holder 22 and the outer second cover 51 rub against each other becomes longer, and the frictional charge amount of both the first holder 22 and the outer second cover 51 increases. In order to make this point invalid, it is particularly effective to form the first holder 22 from polytetrafluoroethylene having a particularly low dielectric constant.

  The entire surface of the outer second cover 51 is also formed with an insulating hard coating 15 formed by anodizing. Similarly to the hard coating 10, the thickness of the hard coating 15 is about 30 μm, but may be any thickness as long as it is in the range of 10 μm to 100 μm.

  Further, as shown by hatching in FIG. 6, two contact regions 16 where the hard coating 15 is not formed are formed on the surfaces 68 a and 69 a of the notches 68 and 69. The surfaces 68a and 69a are surfaces that contact when the protrusion forming members 66 and 67 are fixed to the notches 68 and 69, respectively. For this reason, the projection forming members 66 and 67 and the base material of the outer second cover 51 are electrically connected. Since the projection forming members 66 and 67 in the present embodiment are fixed to the base material of the outer second cover 51 on which the hard coating 15 is formed by performing alumite treatment in a state where the contact region 16 is masked, The hard film 15 is not formed on the members 66 and 67. Therefore, when both the housing members 2 and 3 are assembled, the contact region 11 of the outer first cover 21 and the projection forming members 66 and 67 are brought into contact and electrically connected, and both the covers 21 and 51 are grounded. It will be. In addition, the hard coating 15 is not formed on the entire surface of the protrusion forming members 66 and 67, and this surface itself becomes a contact region, but the surface itself is made of stainless steel. Harder than the substrate. Therefore, when the both covers 21 and 51 are assembled, it is possible to suppress the occurrence of scraping or galling due to friction between the covers in the fitting region. Moreover, you may form the contact area | region 16 by performing a cutting process after performing an alumite process similarly to the above-mentioned.

  In the present embodiment, the protrusion forming members 66 and 67 may be formed integrally with the outer second cover 51. In this case, the contact area where the hard coating is not formed is in the fitting area where the outer first and second covers 21 and 51 are fitted when the two housing members 2 and 3 are assembled. 11 may be formed in a region facing 11. In other words, the hard coating 15 only needs to be formed in the fitting region excluding the contact region. Furthermore, a hard film may be formed only on the tip surface facing the bottom surface of the groove 32 of the protrusions 51a and 51b. If the hard coating is formed in this way, when both covers are assembled, it is possible to suppress the occurrence of scraping or galling due to the friction between the covers in the fitting region.

  As shown in FIG. 3, the second holder 52 has a substantially disk shape, and is a recess into which the downstream end of the inner second case 53 in the suction direction A is fitted on the surface facing the inner second case 53. 63 is formed. A hole 64 is formed in the center of the bottom surface of the recess 63 and constitutes a part of a discharge path for gas discharged from the filter cartridge 4. As shown in FIG. 4, an annular protrusion 52a that includes the hole 64 and is inserted into the hole 61a is formed on the surface of the second holder 52 opposite to the surface on which the concave portion 63 is formed. The second holder 52 is formed with a hole 52b that faces the hole 61b and has the same diameter as the hole 61b when fixed to the outer second cover 51. The core wire of the coaxial cable connected to the inner second case 53 and the insulating member covering the core wire are also passed through the hole 52b.

  As shown in FIG. 4, the inner second case 53 has a tapered surface 53a inclined with respect to the suction direction A, a straight surface 53b extending along the suction direction A, and a curve connecting the tapered surface 53a and the straight surface 53b. It has an inner peripheral surface consisting of a surface 53c. Further, an annular protrusion 65 protruding in the radial direction is formed on the outer periphery of the end portion of the inner second case 53 opposite to the second holder 52. The annular protrusion 65 has the same outer diameter as the largest outer diameter of the enlarged diameter portion 23 b of the inner first case 23. The inner second case 53 is fixed to the second holder 52 in a state in which the downstream end of the inner second case 53 in the suction direction A is fitted in the recess 63 by screwing in from the outer side of the second holder 52. Has been.

  As shown in FIG. 4, the joint holder 54 includes an inner cylinder 71 that is fitted between the hole 61 a of the annular flange 61 and the annular protrusion 52 a of the second holder 52, and an outer cylinder 72 that is disposed outside the inner cylinder 71. And an annular flange 73 that connects the inner and outer cylinders 71, 72. On the inner peripheral surface of the inner cylinder 71, a female screw is formed from the vicinity of the center to the downstream end in the suction direction A, and the connecting member 70 is screwed into this female screw portion. An annular protrusion 52 a of the second holder 52 is fitted into the upstream end portion of the inner cylinder 71. An annular groove is formed on the outer peripheral surface of the annular protrusion 52a, and an O-ring is disposed in the annular groove. Thereby, the sealing performance between the inner cylinder 71 and the holder 52 is improved. The joint holder 54 is screwed into the second holder 52 from the outside of the joint holder 54, so that the annular flange 61 is sandwiched between the joint holder 54 and the second holder 52. The three members 51, the second holder 52 and the joint holder 54 are fixed.

  In the present embodiment relating to the filter unit 5, the same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  Next, the filter cartridge 4 will be described below with reference to FIGS. In addition to the description in the first embodiment, in the case of this embodiment, as shown in FIG. 7, the outer peripheral side surface farthest from the center of the enlarged diameter portion 4b is chamfered in a polyhedral shape (for example, a 16-sided shape). Thereby, even if the filter cartridge 4 removed from the housing 1a is placed on a flat surface so that the outer peripheral side surface thereof is in contact, the filter cartridge 4 is difficult to roll. For this reason, it is difficult for toner to spill out of the filter cartridge 4, and weight measurement of the filter cartridge 4 collecting the powder can be performed stably.

  The housing 81 is formed with an elongated portion 4a and an upstream half 85 that constitutes the upstream half of the enlarged diameter portion 4b. The long part 4a connects the tip part 86 having an outer diameter slightly smaller than the inner diameter of the tip part 41a, the tip part 86 and the upstream half part 85, and has an outer diameter slightly smaller than the smallest inner diameter of the joint part 41b. It has the joint part 87 which has.

  The distal end portion 86 has substantially the same length as the distal end portion 41a in the suction direction A, and when the filter cartridge 4 is inserted into the inner first case 23, the upstream end of the distal end portion 86 and the distal end portion 41a. The upstream end is disposed at substantially the same position. The connecting portion 87 has substantially the same length as the connecting portion 41b in the suction direction A. Three contact portions 88 and three protrusions 89 that extend in the suction direction A and protrude from the outer peripheral surface are formed on the outer peripheral surface of the connecting portion 87 and in the downstream end in the suction direction A. The abutting portions 88 and the protrusions 89 are arranged apart from each other along the circumferential direction, and are alternately arranged.

  The three contact portions 88 have a prismatic shape extending in the suction direction A, and the height from the outer peripheral surface of the connecting portion 87 is lower than the protrusion 89. Specifically, when the filter cartridge 4 is inserted into the inner first case 23, the contact portion 88 passes without contacting the inner peripheral surface of the collar 45 and contacts the pedestal 47 b. The filter cartridge 4 is urged in the suction direction A by the urging member 47. Thus, the filter cartridge 4 is urged in the suction direction A, whereby the downstream end of the filter cartridge 4 can be pressed against the side surface of the second holder 52. Therefore, the sealing performance of the connection portion between the discharge port 98 and the hole 64 of the filter cartridge 4 is improved, and the suction force surely acts on the suction port 86a of the filter cartridge 4. As a result, the powder can be reliably sucked and collected in the filter cartridge 4, and the powder is mistakenly sucked into the gap between the inner first case 23 and the filter cartridge 4 from between the two end portions 41 a and 86. Disappears.

  The three protrusions 89 have a triangular prism shape extending in the suction direction A, and the sharp tips of the protrusions 89 are arranged at positions farthest from the outer peripheral surface of the connecting portion 87. Further, the protrusion 89 has a height such that when the filter cartridge 4 is inserted into the inner first case 23, the tip is in contact with the inner peripheral surface of the collar 45 and is crushed. As a result, when removing the filter cartridge 4 from the housing 1a, the collar 45 and the projection 89 are engaged with each other, so that the filter cartridge 4 is unlikely to come off from the first housing member 2. Therefore, the powder is less likely to spill from the filter cartridge 4. Further, the upstream end surface of the protrusion 89 in the suction direction is inclined. Therefore, when the filter cartridge 4 is inserted into the inner first case 23, the tip of the protrusion 89 is easily crushed. When the filter cartridge 4 is inserted into the inner first case 23, the protrusion 89 and the collar 45 come into contact with each other, so that the filter cartridge 4 and the inner first case 23 are electrically connected.

  As shown in FIGS. 7A and 8, four ribs 91 are formed in the upstream half 85. The rib 91 has a substantially triangular shape extending from the vicinity of the inlet of the upstream half 85 to the vicinity of the outer peripheral end of the upstream half 85 along the inclined surface 85a. These ribs 91 are disposed at positions 90 degrees apart from each other about the central axis of the upstream half 85. The downstream end surfaces of these ribs 91 are disposed at positions where they can come into contact with the upstream surface of the filter 83 housed in the filter cartridge 4, and come into contact with the filter 83 when sucking powder. Thus, the range of vibration of the filter 83 is regulated. Therefore, the filter 83 can be prevented from being damaged by being greatly deformed, and the filter 83 can reliably capture the powder.

  Further, in the vicinity of the outer peripheral end portion of the upstream half portion 85, an annular welded portion 85b extending along the circumferential direction for welding the housings 81 and 82 is formed. Thus, the two housings 81 and 82 can be welded together by fitting them together with the filter 83 sandwiched between the two housings 81 and 82 and heating the welded portion 85 b from the outside of the filter cartridge 4. Both housings 81 and 82 may be fixed with an adhesive. In this case, the welded portion 85b may not be formed.

  The housing 82 is formed with a short portion 4c and a downstream half 92 that constitutes the downstream half of the enlarged diameter portion 4b. The short part 4c has an outer diameter slightly smaller than the smallest inner diameter of the inner second case 53 (the inner diameter of the straight surface 53b portion). An annular protrusion 95 is formed at the downstream end of the short portion 4c. The outer diameter of the annular protrusion 95 is substantially the same as the smallest inner diameter of the inner second case 53.

  In the downstream half 92, as shown in FIG. 7B and FIG. 8, the outer peripheral ends of the downstream half 92 are orthogonal to each other and extend along the inclined surface 92a from the boundary between the short portion 4c and the downstream half 92. Two substantially trapezoidal ribs 93 extending to the vicinity are formed. The upstream end surfaces of the ribs 93 are disposed at positions where they can come into contact with the downstream surface of the filter 83 housed in the filter cartridge 4, and come into contact with the filter 83 when sucking powder. The range of vibration of the filter 83 is regulated. Therefore, the filter 83 can be prevented from being damaged by being greatly deformed, and the filter 83 can reliably capture the powder. In addition, a notch 93 a is formed at the downstream end of each rib 93.

  Next, an operation until obtaining the charge amount per unit weight of the powder sucked using the powder charge measuring device 1 will be described with reference to the drawings.

  First, the user measures the weight of the filter cartridge 4 alone with an electronic balance. Then, as shown in FIG. 9, the user places the filter cartridge 4 between the separated first and second housing members 2, 3, and the elongated portion 4 a of the filter cartridge 4 is placed inside the first case. 23 is inserted into the long portion 23a. At this time, the contact portion 88 contacts the pedestal 47 b, the tip of the projection 89 comes into contact with the inner peripheral surface of the collar 45 and is crushed, and the projection 89 and the collar 45 are engaged. At this time, the filter cartridge 4 and the inner first case 23 are electrically connected via the collar 45, and the filter cartridge 4 and the inner second case 53 are in direct contact with each other.

  Next, the positions of the covers 21 and 51 are adjusted so that the protrusions 51a and 51b can pass through the notches 38a and 38b. And the 1st and 2nd housing members 2 and 3 are moved to the direction which mutually approaches, and covers 21 and 51 are fitted. Before the covers 21 and 51 are fitted together, the downstream end in the suction direction A of the inner first case 23 is more than the downstream end of the first holder 22 by the biasing force of the biasing member 49 as shown in FIG. It protrudes in the suction direction A. However, by fitting the covers 21 and 51 together, as shown in FIG. 4, the downstream end surface of the inner first case 23 and the upstream end surface of the annular protrusion 65 of the inner second case 53 come into contact with each other. The case 23 is pushed into the first holder 22. At this time, the pressing force of the upstream end surface of the annular protrusion 65 against the downstream end surface of the inner first case 23 is increased by the biasing force of the biasing member 49, so that the electrical contact between the inner first case 23 and the inner second case 53 is performed. The state becomes even more certain. Furthermore, when the outer first and second covers 21 and 51 are fitted to each other and the protrusions 51a and 51b and the annular protrusion 33 are engaged with each other, The pressing force of the inner second case 53 with respect to the downstream end surface of the inner first case 23 is reduced, but by providing the urging member 49, the backlash between the covers 21, 51 is absorbed, and the inner first case A decrease in pressure contact force between the case 23 and the inner second case 53 is suppressed.

  Further, when the covers 21 and 51 are fitted to each other, the urging force of the urging member 47 acts on the filter cartridge 4, so the pressure contact force between the downstream end surface of the filter cartridge 4 and the side surface of the second holder 52. Becomes larger. As a result, the powder can be reliably sucked and collected in the filter cartridge 4 as described above, and the powder is not accidentally sucked into the gap between the inner first case 23 and the filter cartridge 4.

  Next, after fitting the outer first and second covers 21 and 51, the user rotates the first housing member 2 by 90 °. Then, an engaging portion (not shown) formed in the groove 32 engages with the protrusions 51a and 51b. Thereby, the 1st housing member 2 and the 2nd housing member 3 are assembled | attached in the state which is hard to rotate, and the housing | casing 1a is comprised. As described above, when the outer first and second covers 21 and 51 are fitted to each other and rotated by 90 °, the protrusions 51 a and 51 b and the annular protrusion 33 are further connected between the annular protrusion 33 and the outer second cover 51. Even if it comes into contact with the peripheral surface, since the hard coatings 10 and 15 are formed there, the occurrence of scraping or galling is suppressed. For this reason, both covers 21 and 51 can be repeatedly assembled and separated. Further, since the first holder 22 is made of polytetrafluoroethylene having a very small relative dielectric constant, when the housing members 2 and 3 are fitted (including when rotated by 90 °), the first holder 22 and the outer side Even if the inner peripheral surface of the second cover 51 comes into contact with each other, electric charges due to friction are hardly generated between the two. For this reason, the charge amount in the inner first and second cases 23 and 53 can be accurately measured.

  Then, the contact region 11 of the outer first cover 21 and the protrusions 51a and 51b of the outer second cover 51 come into contact with each other, and both the covers 21 and 51 are also electrically connected. Even when the hard coatings 10 and 15 are provided in this way, when the covers 21 and 51 are assembled, the covers are electrically connected to each other, so that the amount of charge in the inner first and second cases can be reduced. In the measurement, the influence of the external electric field can be effectively eliminated.

  The urging force of the urging member 49 also acts in the direction in which the covers 21 and 51 are separated (a direction parallel to the fitting direction), so that the engagement force between the protrusions 51a and 51b and the annular protrusion 33 is increased and the electric force is increased. The contact state is more reliable.

  Next, the user drives the suction pump to generate a suction force at the suction port 86a of the filter cartridge 4 incorporated in the powder charge measuring device 1, and sucks the powder together with gas from the outside into the filter cartridge 4. . At this time, the sucked powder is captured by the filter 83, and the gas is discharged from the discharge port 98 to the suction pump side through the discharge path (holes 64 and 70a, the piping member 6 and the filter unit 5). If the filter 83 of the filter cartridge 4 is damaged or not properly attached, or if the filter 83 is damaged during the operation of the suction pump and if powder is collected in the filter unit 5, The same measures may be taken as described in one embodiment.

  Next, the drive of the suction pump is stopped, and when the powder is not collected in the filter unit 5, the total charge amount of the powder in the filter cartridge 4 is measured. Here, in the fitting region of both housing members 2, 3, the outer peripheral surface of the annular protrusion 33 of the outer first cover 21 and the outer peripheral surface of the annular protrusion 36 of the first holder 22 are engaged with both housing members 2, 3. Since it partially contacts with the inner peripheral surface (surface facing the direction orthogonal to the fitting direction) of the outer second cover 51 when it is rotated (including when rotated by 90 °), there is friction on each surface. Due to the charge. In particular, as shown in FIG. 4, since the area of the outer peripheral surface of the annular protrusion 36 and the inner peripheral surface of the outer second cover 51 opposite to the outer surface is larger than that of other parts, a large amount of charge is generated on these surfaces. Arise. However, in the present embodiment, since the relative permittivity of the first holder 22 is extremely small, there is a very small amount of charge on the outer peripheral surface of the annular protrusion 36 and the inner peripheral surface portion of the outer second cover 51 opposite to the outer peripheral surface. Only occurs. Charges E0a and E0b equivalent to these charges are transferred to the capacitor C formed between the inner first and second cases 23 and 53 and the outer first and second covers 21 and 51 (ground in the drawing). Occurs (see FIG. 10). As described above, since the charges E0a and E0b generated in the capacitor C are extremely small, the measurement of the charge amount of the powder in the filter cartridge 4 described later hardly affects. As a result, the amount of charge in the inner first and second cases 23 and 53 can be accurately measured.

  In addition, after preparing two types of constituent materials of the first holder 22 having different relative dielectric constants and repeating the assembly and separation of the housing members 2 and 3 about 5 times, the charge amount of the charge generated by friction is measured. Experiments were performed for each. That is, an experiment was performed on the first holder made of polyacetal resin (relative dielectric constant 3.7) and that made of polytetrafluoroethylene. As a result, when the first holder was made of polyacetal resin, it was -0.9 nC. On the other hand, when the first holder 22 was made of polytetrafluoroethylene or polycarbonate, the value was 0.1 nC. Thus, when the relative permittivity of the first holder 22 is as small as 3.0 or less, the amount of charge generated by friction is small. In the fitting form in the present embodiment, the effect of suppressing the charge amount is particularly remarkable.

  The state of electric charges and lines of electric force in the filter cartridge 4 are the same as described in the first embodiment.

  Next, when the user measures the total weight of the filter cartridge 4 and the powder with an electronic balance and divides the total charge amount of the powder by the total weight of the powder, the charge per unit weight of the powder The amount can be determined.

  As in the first embodiment, if the two housings 81 and 82 are made of a synthetic resin to which a conductive material is added, particularly accurate weight measurement is performed. In addition, it is comprised from the synthetic resin to which the electroconductive material is not added, and the electrically conductive film apply | coated by the spray etc. may be formed in the whole outer surface of the two housings 81 and 82. FIG. Furthermore, you may be comprised from the synthetic resin of the insulator to which the electroconductive material is not added.

As described above, according to the present embodiment, since the housing 1a has a two-part structure into which the housing 1a can be fitted, the work for inserting and removing the filter cartridge 4 is simplified. In addition, at the time of the next measurement, it is only necessary to replace the filter cartridge 4 with a new one, and there is no need to disassemble and clean the suction nozzle portion or the like as in the prior art, improving the workability of the measurement. Further, even when both the housing members 2 and 3 are fitted, the outer peripheral surface of the annular protrusion 36 and the inner peripheral surface of the outer second cover 51 come into contact with each other. Since one holder 22 is made of polytetrafluoroethylene, which is a low dielectric constant material, the amount of charge generated is reduced. This effect is particularly noticeable in the present embodiment. Therefore, it becomes difficult to affect the measurement of the charge amount of the powder in the filter cartridge 4.
In addition, both the housings 2 and 3 can be assembled more firmly than in the first embodiment.

  As a first modification of the second embodiment, as shown in FIG. 11, conductive films 201 to 204 applied to the surfaces of the outer first cover 21, the first holder 22, and the outer second cover 51 by spraying or the like. May be partially formed. In the present modification, the same conductive films 201 to 204 as those in the first embodiment are used.

  The conductive film 201 is mainly the inner peripheral surface of the outer first cover 21 on the hard coating 10, and is along the inner surface of the annular flange 31, the outer peripheral surface of the annular protrusion 33, and the fitting direction. It is also formed on the surface facing. Furthermore, the conductive film 201 is in contact with the contact region 11, and the conductive film 201 and the base material of the outer first cover 21 are electrically connected. The conductive film 202 is mainly formed on the outer peripheral surface of the first holder 22 (including the outer peripheral surface of the annular protrusion 36), and the conductive film 203 is mainly formed on the inner peripheral surface of the first holder 22. The films 202 and 203 are not formed on the outer peripheral surface of the distal end portion 22a or the outer peripheral end surface on the right side of the annular protrusion 36 so as not to be electrically connected to each other. When both the outer first cover 21 and the first holder 22 are fixed with screws, the conductive films 201 and 202 and the base material of the outer first cover 21 are electrically connected to each other through the screws. . On the other hand, the conductive film 203 contacts each other when the first holder 22 and the inner first case 23 are fixed, and is electrically connected to the inner first case 23.

  The conductive film 204 is formed on the hard coating 15 on the inner peripheral surface in the fitting region of the outer second cover 51 (the inner peripheral surface portion facing the outer peripheral surface of the annular protrusions 33 and 36 in the direction orthogonal to the fitting direction). Is formed. Furthermore, the conductive film 204 is in contact with the contact region 16, and the conductive film 204 and the base material of the outer second cover 51 are electrically connected.

  The first housing member 2 having the outer first cover 21 and the first holder 22 in which the conductive films 201 to 203 are formed, and the second housing member 3 having the outer second cover 51 in which the conductive film 204 is formed. When the outer peripheral surfaces of the annular protrusions 33 and 36 are in contact with the opposing inner peripheral surface of the outer second cover 51, no electric charge due to friction remains on the contact surfaces. That is, even if the hard coatings 10 and 15 having insulating properties are formed, the conductive films 201 and 204 are formed there, and the conductive film 204 is also formed on the outer peripheral surface of the annular protrusion 36. The electric charge generated on each surface escapes to the outer first and second covers 21 and 51 grounded through the conductive films 201, 202 and 204 and does not remain. Therefore, it becomes difficult to affect the measurement of the charge amount of the powder in the filter cartridge 4.

  Also in this modified example, after the assembly and separation of the housing members 2 and 3 were repeated about 5 times, an experiment was performed to measure the amount of charge generated by friction. At this time, only the outer first and second covers 21 and 51 are separate from the outer first and second covers 21 and 51 and the first holder 22 in which the conductive films 201 to 204 are formed. The same experiment was performed for the case where the conductive films 201 and 204 were formed and the case where the conductive films 202 and 203 were formed only on the first holder 22. As a result, what formed the electrically conductive films 201-204 in the outer 1st and 2nd covers 21 and 51 and the 1st holder 22 was about 0 nC. Further, the one in which the conductive films 201 and 204 are formed only on the outer first and second covers 21 and 51 is −0.45 nC, and the one in which the conductive films 202 and 203 are formed only on the first holder 22 is 0.07 nC. Met. Thereby, in any case, the hard coatings 10 and 15 are formed on the outer first and second covers 21 and 51, the conductive film is not formed thereon, and the first holder 22 is made of polyacetal resin. As a result, the amount of charge generated by friction was smaller. Therefore, if the conductive films 202 and 204 are formed only on either the outer peripheral surface of the annular protrusion 36 that generates a lot of electric charge due to friction or the inner peripheral surface of the outer second cover 51 that opposes the annular protrusion 36, the conductive film 202 or 204 is generated by friction. The amount of charge is reduced, and the measurement of the amount of charge of the powder in the filter cartridge 4 is less likely to be affected. Further, when the conductive films 202 and 204 are formed on both the outer peripheral surface of the annular protrusion 36 and the inner peripheral surface of the outer second cover 51 facing the annular projection 36 as in this modification, the powder in the filter cartridge 4 The measurement of the charge amount is not affected at all, and the measurement accuracy of the charge amount is remarkably improved.

  In this modification, the hard coatings 10 and 15 are formed on the outer first and second covers 21 and 51, but the hard coatings 10 and 15 may not be formed on the covers 21 and 51. . In this case, even if no conductive film is formed on the outer first and second covers 21 and 51, it is possible to obtain substantially the same result as that obtained by providing the conductive film, and the same effect can be obtained. . Thus, as long as the relative dielectric constant of the material constituting the outer first and second covers 21 and 51 is 8.0 or more, both the covers 21 and 51 may be composed of any material. There is no need to form a conductive film, and the relative permittivity of the constituent material of the first holder 22 need not be 3.0 or less.

  If the relative dielectric constant of the material constituting the outer first and second covers 21 and 51 is more than 3.0 and less than 8.0, a hard coating having a relative dielectric constant of 8.0 or more is formed. Good. In this case, for example, various plating treatments such as hard chrome plating and electroless nickel plating, chemical conversion treatment, LD (rust-proof black conductive thin film) treatment, and a combination surface treatment thereof may be used. Note that the hard coating formed by various plating treatments such as hard chrome plating and electroless nickel plating, chemical conversion treatment, LD treatment, and a combination of these surface treatments has conductivity. Examples of the other treatment include a method of applying or dipping a material capable of forming a hard coating onto the surface of the outer first cover 21 and subsequent curing treatment. Also, ion plating, laser irradiation, or quenching can be used. The film described in the present invention may be used when a new film or layer is formed on the surface of the substrate, or when a film or layer having properties (such as curing) different from the substrate itself is formed inside the surface of the substrate. Including. When the hard coating formed by these surface treatments has insulation, the same effect can be acquired if the same method as the above-mentioned embodiment and the 1st modification is performed.

  As a second modification, as shown in FIG. 12, the outer diameter of the annular protrusion (opposing portion) 36 of the first holder 22 may be smaller than the outer diameter of the annular protrusion 33. This makes it difficult for the outer peripheral surface of the annular protrusion 36 to come into contact with the opposing portion of the inner peripheral surface of the outer second cover 51 when the housing members 2 and 3 are fitted together. For this reason, the charge itself due to friction between the surfaces is less likely to occur, and the measurement of the charge amount of the powder in the filter cartridge 4 is less likely to be affected.

  As a third modified example, as shown in FIG. 13, the annular protrusion 36 may not be formed on the first holder 22. In this way, when the housing members 2 and 3 are fitted together, the outer peripheral surface of the annular protrusion 36 does not come into contact with the opposing portion of the inner peripheral surface of the outer second cover 51. For this reason, the charge itself due to friction between the surfaces does not occur, and the measurement of the charge amount of the powder in the filter cartridge 4 is less affected. In these second and third modified examples, the above-mentioned effects can be obtained even when the first holder made of a material having an insulating property and a relative dielectric constant of more than 3.0 and less than 8.0 is used. Is possible.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, the low dielectric constant material constituting the first holder 22 may be a material other than polytetrafluoroethylene, such as polycarbonate or polyethylene. Further, the outer diameter of the annular protrusion 36 in the above-described embodiment may be larger than the outer diameter of the annular protrusion 33. In this case, the relative dielectric constant of at least one of the outer peripheral surface of the annular protrusion 36 and the inner peripheral surface of the outer second cover facing the surface in a direction orthogonal to the fitting direction is 3.0 or less or 8.0 or more. If it is. The conductive films 201 and 203 in the first modification described above may not be formed.

DESCRIPTION OF SYMBOLS 1 Powder electric charge measuring device 1a Case 2 1st housing member 3 2nd housing member 4 Filter cartridge 10,15 Hard coating 21 Outer 1st cover 22 1st holder (insulator)
23 inner first case 36 annular protrusion (opposite part)
51 outer second cover 53 inner second case 83 filter

Claims (11)

A powder charge measuring device having a housing for storing a filter cartridge in which a filter for capturing powder sucked from the outside is stored, and measuring a charge amount of the powder captured in the filter cartridge In
The housing has first and second housing members forming a space for accommodating the filter cartridge by detachably engaged with each other,
The first housing member includes an outer first cover made of a conductive material, an inner first case made of a conductive material housed in the outer first cover, the outer first cover, and the inner first case. Having an insulator disposed between and electrically insulating both,
The second housing member includes an outer second cover made of a conductive material that can be fitted so as to partially cover the outer first cover, and is housed in the outer second cover and electrically connected to the outer second cover. An inner second case made of a conductive material insulated from
The insulator has an outer diameter smaller than an outermost diameter of the outer first cover in a fitting region where both housing members overlap each other, and is separated from an inner peripheral surface of the outer second cover. A characteristic powder charge meter. A powder charge measuring device having a housing for storing a filter cartridge in which a filter for capturing powder sucked from the outside is stored, and measuring a charge amount of the powder captured in the filter cartridge In
The housing has first and second housing members forming a space for accommodating the filter cartridge by detachably engaged with each other,
The first housing member includes an outer first cover made of a conductive material, an inner first case made of a conductive material housed in the outer first cover, the outer first cover, and the inner first case. Having an insulator disposed between and electrically insulating both,
The second housing member has an outer second cover made of a conductive material and an inner second case made of a conductive material housed in the outer second cover and electrically insulated from the outer second cover. And
The insulator, Te opposite region odor both housing members are opposed to each other, the powder charge amount measuring device characterized that you have spaced apart from the second housing member. 3. The powder charge measuring device according to claim 1, wherein the insulator has a relative dielectric constant of 3.0 or less at least on a surface facing the second housing member. 4. The insulator has conductivity imparted to at least a surface facing the second housing member, and the conductivity imparting portion is electrically connected to the outer first cover. Item 3. A powder charge measuring device according to Item 1 or 2. A powder charge measuring device having a housing for storing a filter cartridge in which a filter for capturing powder sucked from the outside is stored, and measuring a charge amount of the powder captured in the filter cartridge In
The housing includes first and second housing members that form a space for housing the filter cartridge by being separably engaged with each other;
The first housing member includes an outer first cover made of a conductive material, an inner first case made of a conductive material housed in the outer first cover, the outer first cover, and the inner first case. Having an insulator disposed between and electrically insulating both,
The second housing member includes an outer second cover made of a conductive material, and an inner second case made of a conductive material housed in the outer second cover and electrically insulated from the outer second cover. ,
The powder charge measuring device, wherein the insulator has a relative dielectric constant of 3.0 or less at least on a surface facing the second housing member. A powder charge measuring device having a housing for storing a filter cartridge in which a filter for capturing powder sucked from the outside is stored, and measuring a charge amount of the powder captured in the filter cartridge In
The housing includes first and second housing members that form a space for housing the filter cartridge by being separably engaged with each other;
The first housing member includes an outer first cover made of a conductive material, an inner first case made of a conductive material housed in the outer first cover, the outer first cover, and the inner first case. Having an insulator disposed between and electrically insulating both,
The second housing member includes an outer second cover made of a conductive material, and an inner second case made of a conductive material housed in the outer second cover and electrically insulated from the outer second cover. ,
The insulator has a conductivity imparted to at least a surface facing the second housing member, and the conductivity imparting portion is electrically connected to the outer first cover. Body charge meter. 6. The powder charge measuring device according to claim 3, wherein the insulator is made of polytetrafluoroethylene or polycarbonate having a relative dielectric constant of 3.0 or less. The powder charge measuring device according to claim 4 or 6, wherein the conductivity imparting portion is constituted by a conductive film made of a material having a relative dielectric constant of 8.0 or more. The both housing members are assembled to each other so that the outer covers and the inner cases are engaged and electrically connected to each other, and the space is formed between the inner cases. The powder charge measuring device of any one of -8. The insulator supports the inner first case in a slidable manner,
Between the insulator and the inner first case, the inner first case is attached toward the inner second case so that the inner cases are pressed against each other in a state where both housing members are assembled. The powder charge measuring device according to any one of claims 1 to 9, wherein a biasing member for biasing is disposed. 2. A biasing member that biases the filter cartridge toward the inner second case in a state where both housing members are assembled is disposed in the inner first case. The powder charge measuring device of any one of 10-10.

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