JP2005294004A - Static eliminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a static eliminator which surely detect a status of air supply. <P>SOLUTION: An air passage 15 through which air is supplied is connected to an ion generation room 20 in which a common discharge electrode 21 is located. Applying a voltage to the common electrode 21 from a voltage source generates a corona discharge, and then generates positive ions and negative ions with the supplied air. A piezo-electric element 24 for measuring an air flow pressure is located on the way of the air passage 15. An output signal from the piezo-electric element 24 is input to a control circuit 30 which can detect irregularities in the status of air supply. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a static eliminator that generates positive and negative ions by applying a voltage to a discharge electrode to cause corona discharge.

Conventionally, as this type of static eliminator, for example, an AC high voltage with a constant amplitude is applied between a discharge electrode and a ground electrode disposed in an ion generation chamber having an air inlet and an air outlet, and corona discharge is performed. In this method, positive and negative ions are alternately generated and neutralized by spraying these positive and negative ions onto the charged body with air supplied from the air suction port. In addition, what was described in following patent document 1 is known as this kind of static elimination apparatus.
JP 2004-6186 A JP 2001-85188 A

  In the above, for example, if some abnormality occurs in a device that supplies air, there is a concern that the supply of air stops or the amount of air supply decreases. If this happens, air stays in the ion generation chamber, so there is a risk that the charge removal performance will deteriorate and the charged body will not be able to be discharged.Furthermore, by performing corona discharge with the air remaining, There was a risk that the amount of ozone generated would increase, thereby causing problems such as corrosion of the discharge electrode.

  On the other hand, the above-described Patent Document 2 describes what detects the supply state of air. In this device, the drive circuit is cooled by injecting a part of the ions to the drive circuit that applies a voltage to the discharge electrode and the ground electrode, and by detecting the temperature of the drive circuit, Whether or not an abnormality has occurred in the supply status is detected.

  However, since the method for detecting the temperature depends on the usage environment of the static eliminator, it is difficult to cope with changes in the usage environment, and it is difficult to accurately detect an abnormality. . In addition, in the static eliminator that intermittently supplies air in accordance with the timing at which the charged body is conveyed, there is a problem that accurate abnormality detection is more difficult because temperature responsiveness to changes in the air supply status is low.

  The present invention has been completed based on the above-described circumstances, and an object thereof is to reliably detect the air supply status.

  As a means for achieving the above object, the invention of claim 1 is characterized in that the air supply path through which air is supplied and the surroundings are covered and a voltage is applied by a voltage power source to generate corona discharge. A discharge electrode capable of generating positive and negative ions, an air discharge port for discharging ions generated at the discharge electrode to the outside from the air supply path, and a flow rate or a flow pressure of air in the air supply path are measured. The present invention is characterized in that it comprises an air flow measuring means for detecting an abnormality and an abnormality detecting means for detecting an abnormality in the air supply status based on the measurement result of the air flow measuring means.

  According to a second aspect of the present invention, in the first aspect, the air discharge port and the discharge electrode are provided in plural on the upstream side and the downstream side in the air supply path, and the air flow measuring means is It is characterized by being arranged in the vicinity of the most downstream air discharge port in the air supply path.

  According to a third aspect of the present invention, in the apparatus according to the first or second aspect, the abnormality detecting means is configured such that the air flow measured by the air flow measuring means is generated by ozone generated around the discharge electrode. It is characterized in that it is detected that an abnormality has occurred in the air supply when it is below a predetermined level that reaches an amount that corrodes the electrode.

  According to a fourth aspect of the present invention, there is provided the control device according to any one of the first to third aspects, further comprising a control unit that stops application of a voltage to the discharge electrode when an abnormality is detected by the abnormality detection unit. It has the characteristics in the place.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, when an abnormality is detected by the abnormality detecting means, an output means for outputting an abnormality detection to the outside is provided. It has a characteristic where it exists.

  A sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, the air flow measuring means includes a piezoelectric element that measures a flow pressure of the air flow. Have.

<Invention of Claim 1>
By measuring the air flow in the air supply path, an abnormality in the air supply status is detected. Compared to the conventional measurement of temperature, the air is not affected by the use environment. It can be reliably detected whether or not it is staying.

<Invention of Claim 2>
Since the air flow is measured at the place where the air is most likely to stay in the air supply path, it is possible to reliably detect an abnormality in the air supply.

<Invention of Claim 3>
It is possible to prevent the discharge electrode from being corroded by the ozone generated around the discharge electrode.

<Invention of Claim 4>
Since the generation of corona discharge in the state where air stays is prevented, the generation of ozone can be suppressed.

<Invention of Claim 5>
By outputting to the outside that an abnormality has occurred in the air supply status, it is possible to urge the operator to take appropriate measures such as maintenance.

<Invention of Claim 6>
As compared with the case where a thermal element is used as the air flow measuring means, the configuration can be simplified and the apparatus can be reduced in size. Furthermore, compared with the conventional method of measuring temperature, the responsiveness to changes in the air supply status is high, so that the detection accuracy can be improved.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS. In the first embodiment, a so-called AC voltage application including, for example, one discharge electrode 21 (hereinafter referred to as a common discharge electrode 21) and a ground electrode 23 to which positive and negative DC high voltages are alternately applied. A type of static eliminator 10 is illustrated.

  First, the structure of the static eliminator 10 will be described. As shown in FIG. 1, the static eliminator 10 is connected to a main body 11 having an air circulation tube 14 and the like to which air is supplied roughly, and generates positive and negative ions by corona discharge while being connected to the air circulation tube 14. It is comprised from a pair of movable part 12 provided with the possible ion production | generation chamber 20. FIG. Both movable portions 12 are provided at two positions spaced apart from each other on the front side surface of the main body portion 11 in the figure, and both are within a predetermined angular range along the arrow direction with respect to the main body portion 11. It is supported so that it can be pivoted up and down (swinged).

  As shown in FIG. 2, the main body 11 is formed in a substantially block shape that is horizontally long, and has an air circulation pipe 14 that penetrates in the lateral direction in the exterior body 13. The air circulation pipe 14 is connected to an air supply device (not shown) capable of pumping air at a predetermined flow rate / flow pressure at the left end in the drawing, and the right end in the drawing discharges air to the outside. Connected to a discharge port (not shown). The internal space of the air circulation pipe 14 serves as an air flow passage 15 through which air flows from the air supply device side (upstream side) to the discharge port side (downstream side) along the arrow direction in FIG.

  The movable part 12 includes a connecting pipe 16 connected in the middle of the air circulation pipe 14, a protruding cylindrical part 17 that protrudes laterally from the middle of the connecting pipe 16 and forms an ion generation chamber 20 inside thereof. It is comprised from the exterior body 18 which covers the circumference | surroundings of the protrusion cylinder part 17. FIG. The connecting pipe 16 is supported so as to be rotatable about its axis with respect to the air circulation pipe 14 by a support portion 14 a formed so as to protrude from the inner surface of the air circulation pipe 14, and has a diameter dimension that is smaller than that of the air circulation pipe 14. The setting is small. An air supply opening 19 that communicates with the ion generation chamber 20 in the protruding cylindrical portion 17 is provided on the side surface of the connecting pipe 16, and air passes through the air supply passage 15 from the air flow passage 15 into the ion generation chamber 20. It comes to be supplied. A common discharge electrode 21 having a tapered substantially cylindrical shape protrudes from the side of the air supply opening 19 on the side surface of the connecting tube 16. The common discharge electrode 21 is arranged concentrically with the protruding cylindrical portion 17, and a sharp tip portion thereof is arranged on the inner side of the air discharge port 22 of the exterior body 18. An annular ground electrode 23 is provided on the outer peripheral surface of the protruding cylindrical portion 17, and is disposed so as to surround the common discharge electrode 21. The air supplied into the ion generation chamber 20 is discharged to the outside from an air discharge port 22 that is an outlet of the ion generation chamber 20. Further, the opening opening of the air discharge port 22 is narrower than the diameter of the protruding cylindrical portion 17 that covers the periphery of the common discharge electrode 21.

  In the present embodiment, the pressure sensor is used to measure the pressure of the air flowing through the air flow passage 15 at a substantially central position in the length direction of the air circulation pipe 14 (substantially intermediate position between the two ion generation chambers 20). A piezoelectric element 24 is provided.

  Next, the circuit configuration of the present embodiment will be described with reference to FIG. As shown in the figure, the outputs of a pair of AC voltage power supplies 31a and 31b whose output voltage amplitude can be adjusted according to the control signal level from the control circuit 30 are connected to the input sides of the pair of switch elements 32 and 32, respectively. Has been. Of the pair of switch elements 32, 32, one output side is via a transformer 33 and a negative voltage doubler rectifier circuit 34, and the other output side is via a transformer 35 and a positive voltage doubler rectifier circuit 36. The common discharge electrode 21 is commonly connected. The control circuit 30 opens and closes the pair of switch elements 32 and 32 at a predetermined timing, so that a positive voltage and a negative voltage are alternately applied to the common discharge electrode 21, and thus the common discharge electrode From 21, positive ions and negative ions can be generated alternately. The ground electrode 23 is grounded. It should be noted that a circuit configuration without the double voltage rectifier circuits 34 and 36 may be used.

  An output signal from the piezoelectric element 24 disposed in the middle of the air flow passage 15 is taken into the control circuit 30 that can detect an abnormality in the air supply status. The control circuit 30 can stop the application to the common discharge electrode 21 by opening the switch elements 32 and 32 according to the level of the signal input at this time.

  Next, the operation of the static eliminator 10 of this embodiment will be described. When the air supply device is driven, air is supplied to the air flow passage 15 at a predetermined flow rate and flow pressure. A part of the supplied air is led into the both ion generation chambers 20 through the air supply openings 19 in the middle of the air flow passage 15, and the other part is discharged from the discharge port to the outside. . In the process in which the introduced air passes through the ion generation chamber 20, a positive and negative DC high voltage is alternately applied to the common discharge electrode 21, thereby generating a corona discharge with the ground electrode 23. Accordingly, positive and negative ions are generated alternately. The positive and negative ions generated in this way are blown toward an external charged body (such as an IC chip) through the air discharge port 22, and the charged body is electrically neutralized. Moreover, since both the movable parts 12 provided with the ion generation chamber 20 and the air discharge port 22 can be rotated within a predetermined angle range with respect to the main body part 11 as described above, the ion blowing angle with respect to the charged body is appropriately set. (See FIG. 1).

  While the static eliminator 10 is driven as described above, the pressure (flow pressure) of the air flowing through the air flow passage 15 is always detected by the piezoelectric element 24. When an output signal from the piezoelectric element 24 is input to the control circuit 30, a numerical value of the pressure obtained based on the signal and a predetermined reference value (for example, 0.05 MPa, this value stored in a memory not shown). The amount of ozone generated around the common discharge electrode 21 reaches 0.05 ppm, which may cause the common discharge electrode 21 to corrode.), And the measured pressure value exceeds the reference value. Then, supply of the power supply voltage is continued, and if it is less than the reference value, an abnormality is detected, and both switch elements 32 and 32 are opened to output a signal to stop the supply of the power supply voltage. Therefore, it is possible to prevent a situation in which corona discharge is generated in a state where air remains in the ion generation chamber 20. As a result, the amount of ozone generated in the ion generation chamber 20 can be reduced, thereby preventing problems such as the common discharge electrode 21 being corroded by ozone.

  As described above, according to the present embodiment, the air flow pressure in the air flow passage 15 is measured by the piezoelectric element 24 to detect an abnormality in the air supply status (retention status). Compared with the conventional one that measures the temperature, it is possible to reliably detect whether or not the air stays without depending on the use environment of the static eliminator 10. In addition, as compared with the case where the flow rate of air is measured with a heat sensitive element, the number of elements itself can be reduced and the heating means is not required, so that the configuration can be simplified. Furthermore, since the air flow pressure is measured, the response to changes in the air supply status is high compared to the conventional method of measuring the temperature. In addition, even when air supply is intermittently performed, accurate abnormality detection can be expected.

  Furthermore, since the application to the common discharge electrode 21 is stopped when an abnormality is detected, the corona discharge is not generated in the state where the air stays in the ion generation chamber 20, and thus the generation of ozone. Can be suppressed.

<Modification>
A modification of the first embodiment will be described with reference to FIG. In this modification, in the static eliminator 10 provided with three movable parts 12 (ion generation chambers 20), an example in which the arrangement of the piezoelectric elements 24 is different from that of the first embodiment is illustrated. In this modification, the subscript A is attached to the reference numeral to distinguish the most downstream movable portion 12 from the other two movable portions 12.

  The piezoelectric element 24 is disposed in the vicinity of the movable portion 12A (air discharge port 22A) disposed on the most downstream side in the air flow passage 15. Specifically, the piezoelectric element 24 is arranged between the end on the discharge port side in the air flow passage 15 and the connecting pipe 16A in the movable portion 12A on the most downstream side, and the flow pressure of the air flowing at this position Is the lowest in the air flow passage 15. In other words, in this modification, the air flow pressure is measured at a place where the air is most likely to stay in the air flow passage 15, so that an air supply abnormality can be reliably detected. Accordingly, it is possible to prevent corona discharge from being generated in a state where air stays in the most downstream ion generation chamber 20A, and to effectively suppress the amount of ozone generated.

<Embodiment 2>
A second embodiment of the present invention will be described with reference to FIG. 5 or FIG. In the second embodiment, a case is shown in which the thermal elements 25 and 26, which are thermal flow sensors, are used in place of the piezoelectric element 24 in the first embodiment, and the air flow rate is measured. In the second embodiment, redundant description of the same structure, operation, and effects as those in the first embodiment will be omitted.

  The structure of the static elimination apparatus 10 of this embodiment is demonstrated previously. As shown in FIG. 5, a pair of heat sensitive elements 25 and 26 are arranged at a substantially central portion of the air circulation pipe 14 with a predetermined distance therebetween. Both the thermal elements 25 and 26 are arranged along the air flow passage 15 on the upstream side and the downstream side, respectively. A heating means 27 (not shown in FIG. 5) is provided near the downstream thermal element 26.

  Next, the circuit configuration of the present embodiment will be described with reference to FIG. As shown in the figure, output signals from both the thermal elements 25 and 26 and the heating means 27 are taken into the control circuit 30. The control circuit 30 can stop the application to the common discharge electrode 21 by opening the switch elements 32 and 32 according to the level of the signal input at this time.

  Next, the operation of the static eliminator 10 of this embodiment will be described. While the static eliminator 10 is being driven, the flow rate of air flowing through the air flow passage 15 is always detected by the two thermal elements 25 and 26 and the heating means 27. Specifically, the downstream heat sensitive element 26 is heated by the heating means 27, and the heat generated in the heating means 27 is such that the difference in temperature measured between the upstream heat sensitive element 25 and the downstream heat sensitive element 26 becomes a predetermined value. Control the amount. Since the heat generation amount at this time is proportional to the flow rate of air flowing through the air flow passage 15, the air flow rate is obtained based on the heat generation amount of the heating means 27. The flow rate of air thus obtained is compared with a predetermined reference value stored in a memory (not shown). If the measured air flow rate is greater than or equal to the reference value, supply of power supply voltage is continued. When an abnormality is detected, a signal is output so that both the switch elements 32 and 32 are opened and the supply of the power supply voltage is stopped. Therefore, it is possible to prevent a situation in which corona discharge is generated in a state where air remains in the ion generation chamber 20. As a result, the amount of ozone generated in the ion generation chamber 20 can be reduced, thereby preventing problems such as the common discharge electrode 21 being corroded by ozone.

  As described above, according to the present embodiment, since the abnormality in the air supply status is detected by measuring the flow rate of air in the air flow passage 15, the temperature is measured as in the past. In comparison, it is possible to reliably detect whether or not the air stays without being influenced by the use environment of the static elimination apparatus 10.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.

  (1) In the first and second embodiments described above, the corona discharge is stopped when an abnormality is detected. However, an abnormality detection output may be performed to the outside. Specifically, when an abnormality is detected, an abnormality detection signal is output via the output circuit 37 (the portion surrounded by the two-dot chain line in FIGS. 3 and 6), and based on the output signal, for example, externally You may make it alert | report to an operator by lighting the arrange | positioned abnormality detection LED. In this way, it is possible to urge the operator to take appropriate measures such as maintenance. Further, based on the output of the abnormality detection signal, the driving of the moving device that sequentially feeds the charged bodies toward the static eliminator 10 may be stopped. In this way, it is possible to automatically prevent the charged body from being neutralized.

  (2) As a modification of the above-described second embodiment, in a static eliminator including three movable parts 12 (ion generation chambers 20), both thermal elements 25 and 26 are arranged on the most downstream side in the air flow passage 15. It may be arranged in the vicinity of the movable part 12. In this case as well, as in the above-described modification of the first embodiment, the air flow rate can be measured at a place where air is most likely to stay in the air flow passage 15, so that air supply abnormality can be reliably ensured. Can be detected.

  (3) As another modification, the piezoelectric element 24, the two thermal elements 25, 26, and the heating means 27 are provided in one static eliminator, and the numerical value of the air flow pressure and the numerical value of the air flow rate are as follows. In both cases, the abnormality may be detected only when the predetermined reference value is not satisfied.

  (4) The number and arrangement of the movable parts 12 (ion generation chambers 20 and common discharge electrodes 21) can be arbitrarily changed. In addition, as shown in FIG. 7, an elongated cylindrical nozzle 28 may be integrally formed on the exterior body 18 to change the position of the air discharge port 22.

  (5) In the above-described embodiment, a so-called AC voltage application type static eliminator has been exemplified. In addition, for example, a so-called AC voltage application type static eliminator is provided. The present invention is also applicable to a DC voltage application type static eliminator.

The perspective view of the static elimination apparatus which concerns on Embodiment 1 of this invention. Schematic cross section of static eliminator Circuit diagram of the static eliminator Schematic sectional view of a static eliminator according to a modification of the first embodiment Schematic sectional view of a static eliminator according to Embodiment 2 of the present invention Circuit diagram of the static eliminator Schematic sectional view of a static eliminator according to another embodiment

Explanation of symbols

10 ... Static eliminator 15 ... Air flow passage (air supply passage)
20 ... Ion generation chamber (air supply path)
21 ... Common discharge electrode (discharge electrode)
22 ... Air discharge port 24 ... Piezoelectric element (air flow measuring means)
25, 26 ... thermal element (air flow measuring means)
27. Heating means (air flow measuring means)
30. Control circuit (abnormality detection means, control means)
31a, 31b ... AC voltage power supply (voltage power supply)
37 ... Output circuit (output means)

Claims (6)

An air supply path through which air is supplied;
A discharge electrode capable of generating positive and negative ions by generating a corona discharge when a voltage is applied by a voltage power source while the surroundings are covered,
An air discharge port for discharging ions generated by the discharge electrode to the outside from the air supply path;
Air flow measuring means for measuring the flow rate or flow pressure of air in the air supply path;
An antistatic device, comprising: an abnormality detecting means for detecting an abnormality in an air supply status based on a measurement result of the air flow measuring means. A plurality of the air discharge port and the discharge electrode are provided on the upstream side and the downstream side in the air supply path,
2. The static eliminator according to claim 1, wherein the air flow measuring means is disposed in the vicinity of the most downstream air discharge port in the air supply path. The anomaly detection means detects an anomaly in the air supply when the airflow measured by the airflow measurement means is below a predetermined level at which ozone generated around the discharge electrode reaches an amount that corrodes the discharge electrode. 3. The static eliminator according to claim 1 or 2, wherein the occurrence of a fault is detected. 4. The static eliminator according to claim 1, further comprising a control unit that stops application of a voltage to the discharge electrode when an abnormality is detected by the abnormality detection unit. 5. 5. The static eliminator according to claim 1, further comprising an output unit configured to output an abnormality detection to the outside when an abnormality is detected by the abnormality detection unit. The static eliminator according to any one of claims 1 to 5, wherein the air flow measuring means is configured by a piezoelectric element that measures a flow pressure of the air flow.

Images