JP2016134248A - Static eliminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray type static eliminator having a neutralization capacity equal to or higher than that of a corona discharge static eliminator, without having such problems as dust adhesion and consumption of a discharge needle in coronal discharge due to blast.SOLUTION: A static eliminator 20 performing static elimination by irradiating a static elimination object, i.e., a film 103, with X-ray includes an X-ray tube 1 for irradiating the outside with an X-ray, a housing 21 for housing the X-ray tube, and including an opening 23 corresponding to an X-ray transmission window, and an electrode 30 for self-discharge provided in the vicinity of the opening of the housing while being grounded. Since self-discharge phenomenon takes place between the electrode 30 for self-discharge at the ground potential and the film, and static elimination of the static elimination object is carried out, static elimination effect equal to or higher than that of a corona discharge static eliminator can be obtained.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a static eliminator that irradiates an object to be neutralized with X-rays radiated from an X-ray tube, and in particular, by providing a self-discharge function in a housing containing an X-ray tube, The present invention relates to a static eliminator that eliminates problems such as dust adhesion, which was unavoidable in the corona discharge type in which ions are sent by air blowing, while achieving a static elimination performance that exceeds that of a corona discharge type static eliminator.

Patent Document 1 listed below discloses an invention relating to a corona discharge type static eliminator.
In the static eliminator, the discharge needle 2 is disposed in an open space 32 that is open to the outside, and a high-voltage AC voltage is applied to the discharge needle 2 to cause corona discharge to generate positive and negative ions. The generated positive and negative ions are ejected to the outside through the opening 43 together with the air flow supplied from the air flow supply pipe 5 through the air inflow hole 34 into the open space 32. The air flow from the air flow supply pipe 5 flows into the through hole 45 through the through hole 13 and the gap 14, and the flow rate of the air flow discharged from the opening 43 through the opening 45 A of the through hole 45 is as follows. An air flow having a higher flow velocity is jetted. Then, the air flow injected from the opening 43 is discharged to the outside so as to be drawn into the air flow from the through hole 45. As a result, the injection distance of the air flow is increased, and the air flow is caused to flow. Thus, ions are jetted over a wide range by the diffused air flow.
According to the present invention, in the corona discharge type static eliminator, an effect of ejecting ions over a wide range is obtained.

Japanese Patent Laid-Open No. 2004-152665

  The corona discharge type static eliminator exemplified in the invention disclosed in Patent Document 1 generates a corona discharge in an open space by applying a high voltage exceeding several kV to a discharge needle to generate positive and negative ions. Is discharged to the object to be neutralized by blowing air.

  In the case of the corona discharge type, fine particles in the air are adsorbed on the electrode part and become particles and re-scatter, causing dust, and there is a problem that dust that has been blown up by blowing air is blown to the static elimination object and attached. To do. In particular, when the object to be neutralized is a product that requires a high degree of cleanliness, such as an industrial high-functional film, a household wrap film, a beverage packaging film, etc., such a problem of dust adhesion cannot be overlooked. In addition, due to the adhesion of dust, the electrode is soiled and the charge eliminating effect is lowered, so that frequent electrode cleaning is required.

  Furthermore, the discharge needle to which a high voltage is applied is easily consumed, and there is a problem in that fine fragments of the discharge needle consumed during use adhere to the object to be neutralized together with the above-mentioned dust. In order to suppress the consumption of the discharge needle, it is conceivable to adopt W or Ti, which are generally considered to be highly durable, as a material. However, this causes another problem of an increase in manufacturing cost. Even if the discharge needle is made of Ti or Ti, there is no guarantee that consumption due to high voltage can be completely suppressed.

  Furthermore, in the conventional corona discharge type static eliminator, a high voltage alternating current is applied to the discharge needle, but the alternating frequency needs to be changed according to the distance between the static elimination object and the discharge needle, and the control is complicated. There was also a problem of generating problems and electromagnetic noise. In addition, ozone is generated due to specific UV light emitted during corona discharge, and there is also a problem that the surroundings are adversely affected by the oxidizing action of ozone.

  The present inventors have proposed a static eliminator (X-ray static eliminator) using an X-ray tube that emits X-rays as an alternative to the conventional corona discharge static eliminator having the above-mentioned problems. Yes. The contents to be described below are matters relating to new knowledge and technical development problems that the inventors of the present application have found in the process of researching and developing an X-ray static eliminator.

  The X-ray tube for the X-ray type static eliminator proposed by the inventors of the present application is such that the window part opened in the hermetic container is closed with an X-ray transmission window from the outside, and the window part and the X-ray transmission window are inside the hermetic container. Is an apparatus having a structure in which an X-ray target is provided and various electrodes such as a cathode are installed in an airtight container. Electrons emitted from the cathode are projected onto the X-ray target to emit X-rays from the X-ray target. It is possible to radiate and irradiate the X-ray transmission window to the outside.

  Ions are always generated by the X-rays irradiated from the X-ray tube, and the ions generated in the vicinity of the charged body directly contribute to static elimination, so that it is not necessary to send ions by blowing as in the corona discharge type. Also, since the same amount of positive and negative ions are generated at the same time in the X-ray irradiation range, there is no bias in the balance of the generated ions, and the amount of positive and negative ions in the discharge area as in the corona discharge type There is no need to adjust. The X-ray static eliminator has no problem of dust adhering to the static eliminator by blowing as in the corona discharge static eliminator described above, and does not require any maintenance such as frequent electrode cleaning. Since the same amount of negative ions is generated at the same time and the ion balance is good, reverse charging does not occur. Furthermore, there is no problem such as consumption of the discharge needle due to application of a high voltage, and there is no problem that complicated frequency control is required according to the distance to the object to be neutralized.

  As described above, the X-ray type static eliminator proposed by the inventors of the present application has various advantages over the corona discharge type static eliminator, but the inventor of the present application is also required to compare with the corona discharge type static eliminator. Conducted an experiment to evaluate and compare the static elimination ability of the X-ray static elimination device and the corona discharge static elimination device using a film static elimination evaluation device 100 as shown in FIG. Here, the X-ray type static eliminator targeted for evaluation and comparison is an X-ray type static eliminator with high output for industrial films, and the corona discharge type static eliminator is the same as this X-ray type static eliminator. The one with about output was selected.

  The film static elimination evaluation apparatus 100 of FIG. 7 arranges two aluminum rollers 101, 101 at two lower positions of four corners of a rectangle, and arranges two urethane rubber rollers 102, 102 at two upper positions, A film 103 made of the same material as the film to be neutralized is wound around these rollers 101 and 102 in an endless belt shape so that a part of the rollers can be driven to rotate the film 103 in a predetermined direction indicated by a letter. It is composed. In this example, the film 103 is made of vinyl chloride and has a width of 30 cm and a total length of 2.4 m. On the upstream side of the film 103 between the two urethane rubber rollers 102 located above, the static eliminator A is disposed downward so as to face the upper surface of the film, and the electrometer 104 is disposed downward on the downstream side to eliminate static electricity. It is configured so that the potential of the film 103 immediately after can be measured.

  Using this film static elimination evaluation apparatus 100, the static elimination capability of each static elimination apparatus was evaluated. When the rollers 103 are driven to move the film 103, the film 103 is charged with static electricity due to the friction between the urethane roller 102 and the film 103. After the film 103 is charged to a predetermined charging voltage before static elimination, immediately after the film 103 is rotated once at a constant film conveyance speed while static elimination is performed by the static elimination apparatus A, the charging voltage of the film 103 is measured by the electrometer 104. . In addition, the static elimination distance of the static elimination apparatus A was set to three types, and the said measurement was performed at each speed, changing the film conveyance speed.

  FIG. 8 is a graph showing comparison results of evaluation experiments in which the static elimination performances of the X-ray static elimination device and the corona discharge static elimination device are evaluated by the film static elimination evaluation device 100. The vertical axis represents the charging voltage (kV) after static elimination of the film, and the horizontal axis represents the film conveyance speed (m / min). In the figure, a graph showing the static elimination capability of the X-ray static elimination device is shown by a solid line, and a graph showing the static elimination capability of a corona discharge type static elimination device having an output comparable to this is shown by a broken line. The static elimination distance of each static eliminator was set to 2 cm (black circle mark), 5 cm (black triangle mark), and 10 cm (black square mark). Further, in the graph of FIG. 8, the lowermost substantially parallel line indicates the pre-static charge voltage, which is about −43 kV in this example.

  As can be seen from the graph shown in FIG. 10, in the X-ray static elimination apparatus (solid line), as the film speed increases, the static elimination capability rapidly decreases, and the negatively charged film cannot be sufficiently eliminated. On the other hand, in the corona discharge type static eliminator (broken line), the reduction in static eliminability with respect to the increase in film speed is gentle.

  Thus, according to the study by the present inventors, at least according to a comparative experiment using the evaluation apparatus 100 as shown in FIG. In addition, the corona discharge type static eliminator had a better static elimination capability. However, this is considered to be a result of using a film static elimination evaluation apparatus as shown in FIG. This is not necessarily the case, but this is not always the case when an experiment is conducted with a static elimination plate monitor, which is another static elimination evaluation apparatus, rather than a film static elimination evaluation apparatus that evaluates the ability to remove the charge of a moving film. It was because it was not obtained. The neutralization plate monitor is a neutralization capability of the neutralization device by charging the insulated plate (iron plate) to a predetermined high voltage and then starting neutralization with the neutralization device, and recording the charging voltage of the plate that decreases over time. It is a device that evaluates.

This is because, in the case of a charged plate monitor, the charge removal object is a metal plate, and the film 103 as shown in FIG. It is considered that the evaluation apparatus 100 that performs charge removal by charging is different in electrostatic state. Considering these facts together, at least when a film that is easily charged is targeted for static elimination, and when static elimination is performed while moving the film continuously at a considerable speed, both types of static elimination devices The present inventors have come to consider that a difference in evaluation occurs between the two.
The present inventors consider that such experimental facts and interpretation thereof are new findings in the technical field.

  The present invention was made on the basis of the above-described conventional technology and novel knowledge obtained by analyzing the experimental results by the inventors of the present invention, and charged like a film conveyed at a considerable speed. Even if it is a target that is large and difficult to neutralize, it can be neutralized with the same or better neutralization capacity as a conventional corona discharge neutralization device, and unlike the corona discharge neutralization device, there is no problem of dust adhesion due to air blowing. There is no problem of discharge needle depletion and debris generation that apply high voltage, and there is no complication of controlling the frequency of AC high voltage applied to the discharge needle. It aims at providing the X-ray-type static elimination apparatus which utilized the advantage.

The static eliminator described in claim 1 is:
In a static eliminator that performs static elimination by irradiating a static elimination object with X-rays,
An X-ray tube having an X-ray transmission window for irradiating X-rays to the outside;
A housing that houses the X-ray tube and includes an opening corresponding to the X-ray transmission window;
A self-discharge electrode provided in the vicinity of the opening of the housing and grounded;
It is characterized by comprising.

The static eliminator described in claim 2 is the static eliminator according to claim 1,
The X-ray tube is
A radiopaque substrate having a window formed thereon;
An X-ray transmissive window provided to close the window from the outer surface side of the substrate;
An X-ray target provided on the window from the inner surface side of the substrate;
A flat box type container part attached to the inner surface side of the substrate and the inside of which is in a high vacuum state,
A linear cathode that is provided inside the container and emits electrons that collide with the X-ray target;
A control electrode provided between the cathode and the X-ray target for controlling electrons emitted from the cathode;
It is characterized by comprising.

The static eliminator described in claim 3 is the static eliminator according to claim 2,
The casing and the self-discharge electrode are made of stainless steel, and an insulating member is provided between the X-ray tube and the casing.

  According to the static eliminator described in claim 1, the X-rays irradiated from the X-ray transmission window of the X-ray tube are irradiated to the external static elimination object through the opening of the housing that houses the X-ray tube. , Remove this charge. At that time, since the self-discharge electrode provided in the vicinity of the opening of the housing is set to the ground potential, if the potential difference between the self-discharge electrode and the static elimination object is, for example, about several kV or more, A self-discharge phenomenon occurs in which charge moves between the self-discharge electrode and the object to be neutralized, promotes neutralization of the object to be neutralized, and can provide the same neutralization effect as that of the corona discharge type neutralization device with an equivalent output. . Even when the X-ray tube is turned off and the X-ray is turned off and no static elimination is performed by the X-ray, a self-discharge phenomenon occurs between the self-discharge electrode and the static elimination object. The static elimination effect equivalent to the corona discharge type static elimination apparatus made can be mentioned.

  According to the static eliminator described in claim 2, an X-ray impermeable substrate having a window portion formed thereon, an X-ray transmissive window provided so as to close the window portion from the outer surface side of the substrate, and the substrate X-ray target provided in the window from the inner surface side, a flat box-shaped container portion attached to the inner surface side of the substrate and in which the inside thereof is in a high vacuum state, and an X-ray provided in the container portion As an X-ray source, an X-ray tube composed of a linear cathode that emits electrons that collide with a target, and a control electrode that is provided between the cathode and the X-ray target and controls electrons emitted from the cathode, The above-mentioned effect as a static eliminator can be achieved.

  According to the static eliminator described in claim 3, the X-ray tube to which a relatively high voltage is applied is attached to the inside of the casing installed via the insulating member, and sufficient insulation is provided therebetween. Sex is maintained. The self-discharge electrode that is electrically integrated with the casing is also at the ground potential, and no high voltage is applied. The casing is made of inexpensive stainless steel and is set to the ground potential.

It is a graph which compares and shows the result of the evaluation experiment which evaluated the static elimination capability of the corona discharge type static elimination apparatus (in the case of a power supply ON and OFF) and the conventional X-ray type static elimination apparatus with the film static elimination evaluation apparatus. It is sectional drawing of the X-ray-type static elimination apparatus of this embodiment. It is a schematic perspective view which shows the various aspects of the self-discharge electrode of the X-ray-type static elimination apparatus of this embodiment. It is a schematic diagram which shows the aspect of the structure of the film static elimination evaluation apparatus 100 which evaluates the static elimination capability of the X-ray-type static elimination apparatus of embodiment, and an experiment. Corona discharge type static eliminator (when power is ON and OFF), X-ray type static eliminator of the first embodiment (when X-ray is ON and OFF), and conventional X-ray type static eliminator (X-ray) It is a graph which compares and shows the result of the evaluation experiment which evaluated each static elimination capability in the case of ON) with the film static elimination evaluation apparatus 100. FIG. Corona discharge type static eliminator (when power is ON), X-ray type static eliminator of the second and third embodiments (when X-ray is ON), and conventional X-ray type static eliminator (when X-ray is ON) It is a graph which compares and shows the result of the evaluation experiment which evaluated each static elimination capability with the film static elimination evaluation apparatus. It is a schematic diagram which shows the aspect of the structure and experiment of the film static elimination evaluation apparatus 100 which evaluates the static elimination capability of the conventional X-ray-type static elimination apparatus and a corona discharge type static elimination apparatus. It is a graph which compares and shows the result of the evaluation experiment which evaluated each static elimination performance of the conventional X-ray-type static elimination apparatus and the corona discharge-type static elimination apparatus with the film static elimination evaluation apparatus 100. FIG.

1. Examination of static elimination capability of corona discharge type static eliminator The inventors of the present application are based on the facts explained in the sections of “Background Technology” and “Problems to be Solved by the Invention”, the results of experiments by the inventors of the present application, and this. In view of the new knowledge or problems found in the above, the corona discharge type static eliminator having the same output as the X-ray type static eliminator when evaluated and compared using the film static eliminator having the basic structure as described above. In order to find out the cause of the device's superior static elimination capability, experiments as described below were further conducted.

  FIG. 1 is an evaluation of the corona discharge type static eliminator (when the power supply is ON and OFF) and the static eliminator capability of a conventional X-ray type static eliminator having an output equivalent to the corona discharge type static eliminator 100. It is a graph which compares and shows the result of an experiment. In the experiment, the charging voltage before static elimination was set to -43 kV. As can be seen from this figure, the corona discharge static eliminator has a lower static eliminability when the power is turned off (when the power is turned off) than when the power is turned on, but a certain level of static eliminability is maintained. It has been discovered that when the film transport speed is faster than 50 m / min, it exhibits a higher static elimination capability than a conventional X-ray static elimination apparatus whose power is ON.

This is because when the power is turned off, the potential of the discharge needle to which a high voltage was applied during static elimination decreases, and the charge moves between the static elimination object according to the potential difference with the static elimination object. This is thought to be due to the progress of static elimination of objects.
The present inventors consider that such experimental facts and interpretation thereof are new findings in the technical field.

2. The X-ray type static eliminator of the first embodiment The inventors of the present application provided an electrode in the X-ray type static eliminator so that the potential difference from the static elimination object is sufficient, and the charge from the static elimination object to the electrode From the above knowledge, the idea that the static elimination ability can be improved by using the phenomenon of self-discharge in which the static elimination object is neutralized by moving. Such an electrode is referred to as a self-discharge electrode in this embodiment. It is considered that the self-discharge electrode is preferably set to the ground potential (0 V) in order to obtain a sufficient potential difference from the static elimination object. In addition, it is considered that it is necessary to adopt a shape that easily causes self-discharge due to the movement of electric charge and to be provided at a position that does not hinder the irradiation of X-rays from the X-ray type static eliminator.

With reference to FIG. 2, the X-ray-type static elimination apparatus 20 of 1st Embodiment is demonstrated.
The X-ray type static eliminator 20 has an X-ray tube 1 as an X-ray source. This X-ray tube 1 has a flat box type package 2 as a main body. The package 2 is provided with an X-ray transmission window 5 to be described later on the peripheral edge of the open side of the container 3 in which glass plates (one back plate 3a and four side plates 3b) are assembled into a flat box shape. A radiopaque substrate 4 is attached and sealed, and the inside thereof is exhausted so as to be in a high vacuum state. The substrate 4 is a rectangular plate made of 426 alloy. The 426 alloy is an alloy such as 42% Ni, 6% Cr, and the rest Fe, and the thermal expansion coefficient is substantially equal to the soda lime glass constituting the container part 3. In addition, when the material of the container part 3 is a glass plate other than soda lime glass, the substrate 4 may use a metal plate of another material so as to be approximately equal to the thermal expansion coefficient of the container part 3. .

  In the center of the substrate 4, a window portion 6 that is an elongated rectangular opening (slit) is formed to irradiate the outside with X-rays. The window 6 is formed in a substantially rectangular shape extending in the longitudinal direction of the substrate 4 (that is, the longitudinal direction of the package 2). In FIG. 2, the longitudinal direction of the substrate 4, the window 6, and the package 2 is a direction perpendicular to the paper surface. On the outer surface side of the substrate 4, an X-ray transmission window 5 made of a titanium foil larger than the window portion 6 is stuck so as to close the window portion 6. Further, inside the package 2, a tungsten film is deposited on the inner surface of the substrate 4 around the window portion 6 and the inner surface of the titanium foil X-ray transmission window 5 viewed from the window portion 6. A target 7 is formed. The X-ray target 7 is a metal that emits X-rays with high efficiency in response to electron collision, and a metal other than tungsten such as molybdenum can also be used.

  As shown in FIG. 2, inside the container portion 3, that is, inside the package 2, the inner surface of the container portion 3 opposite to the X-ray transmission window 5 (that is, a plate material (back plate 3 a) facing the substrate 4). Is provided with a back electrode 8 for preventing the glass from being charged. A linear cathode 9 as an electron source is stretched directly under the back electrode 8. The cathode 9 is obtained by applying carbonate to the surface of a wire-shaped core wire made of tungsten or the like, and emits thermoelectrons by energizing and heating the core wire.

  A first control electrode 10 for extracting electrons from the cathode 9 is provided below the cathode 9 (on the X-ray transmission window 5 side). The first control electrode 10 is formed with a slit-like opening 10a, and a mesh is provided in the opening 10a.

  Further, below the first control electrode 10 (on the X-ray transmission window 5 side), a second control electrode 11 that restricts the irradiation range of the electron beam is provided. The second control electrode 11 is a box-shaped electrode member in which the four sides of a substantially rectangular central plate body 11b are surrounded by the plate body 11c, respectively, and are arranged so as to surround the back electrode 8, the cathode 9, and the first control electrode 10. ing. A slit-shaped opening 11 a is formed in the center plate 11 b of the second control electrode 11 at a position corresponding to the linear cathode 9. The opening 11 a has a smaller width than the opening 10 a of the first control electrode 10, and a mesh is provided in the same manner as the opening 10 a of the first control electrode 10.

  According to this embodiment, the cathode 9 as an electron source is surrounded by the first and second control electrodes 10 and 11 to which a predetermined potential is applied, so that the inner surface of the container portion 3 is charged. The potential around the cathode 9 is stable without being affected by the electric charge, and the emission of electrons from the cathode 9 is stable.

  Note that the back electrode 8 need not be provided because the effect of charging of the container part 3 is small as long as the distance between the container part 3 and the linear cathode 9 is sufficiently maintained. Further, as the control electrode, in addition to the first control electrode 10 and the second control electrode 11 described above, the distance between the linear cathode 9 and the X-ray target 7, the tube voltage, or the X-ray extracted from the X-ray transmission window 5 is used. Depending on the degree of focusing, other control electrodes may be added as appropriate. In addition, like the substrate 4, the first control electrode 10 and the second control electrode 11 are desirably made of 426 alloy in order to make the thermal expansion coefficient of the container part 3 substantially equal.

  As shown in FIG. 2, the X-ray static eliminator 20 has a predetermined drive voltage applied to each of the back electrode 8, the cathode 9, the first control electrode 10, and the second control electrode 11 constituting the electrode unit 12 of the X-ray tube 1. Is provided. The drive circuit 12 includes four high voltage power supplies 16a, 16b, 16c, and 16d. The high voltage power supply 16a has a cathode connected to the back electrode 8, an anode connected to the X-ray transmission window 5, and is grounded, so that the X-ray transmission window 5 can be set to a ground potential (0V). . The high voltage power supply 16d has an anode connected to the cathode 9 and a cathode connected to the cathode of the high voltage power supply 16a. The high voltage power supply 16c has an anode connected to the first control electrode 10 and a cathode connected to the cathode of the high voltage power supply 16a. The high voltage power supply 16b has an anode connected to the second control electrode 11 and a cathode connected to the cathode of the high voltage power supply 16a. The drive circuit 12 applies a drive voltage from the high voltage power supply 16a to the back electrode 8, and applies a predetermined drive voltage based on the voltage of the high voltage power supply 16a to the cathode 9, the first control electrode 10 and the second control electrode 10. A structure in which the X-ray transmission window 5 side of the X-ray tube 1 is grounded is referred to as anode grounding, and the X-ray tube 1 is driven by the anode-grounded driving circuit 12. This is called anode ground drive.

  An X-ray tube 1 serving as an X-ray source of the X-ray static elimination apparatus 20 is accommodated in a grounded conductive casing 21. A spacer (also having a function as a cushioning material) 22 is provided between the X-ray tube 1 and the inner surface of the housing 21, and the X-ray transmission window 5 of the X-ray tube 1 is grounded. And the same potential. The casing 21 is made of a metal that is easy to process and inexpensive and has good conductivity, such as stainless steel. The casing 21 has an opening 23 for allowing X-rays generated from the X-ray transmission window 5 to pass through a wall portion facing the X-ray transmission window 5 which is an X-ray emission surface of the X-ray tube 1. Is formed.

  As shown in FIG. 2, a self-discharge electrode 30 is attached to the outer surface of the housing and in the vicinity of the opening 23 on the X-ray irradiation side. The self-discharge electrode 30 has a needle shape with a sharp tip, and is made of stainless steel, and is mechanically and electrically integrated with the housing 21. The self-discharge electrode 30 is perpendicular to the lower surface of the housing 21 and is substantially parallel to the X-ray irradiation center line C irradiated from the X-ray tube 1 toward the charge removal object. The length and installation position of the self-discharge electrode 30 are set so as not to contact the irradiation range of X-rays irradiated from the X-ray tube 1 through the opening 23. Furthermore, the self-discharge electrode 30 is not limited to the single electrode shown in FIG. 2, but a plurality of self-discharge electrodes 30 are provided at predetermined intervals along the longitudinal direction of the casing 21 and the opening 23 as shown in FIG. It has been.

  As shown in FIG. 2, a power supply unit 24 and a printed circuit board 25 are disposed in the housing 21. The power supply unit 24 is an example in which the high voltage power supplies 16a, 16b, 16c, and 16d in the drive circuit 12 indicated by circuit symbols in FIG. 2 is an insulating spacer for holding the X-ray tube 1, the power supply unit 24, and the printed board 25 at predetermined positions in the housing 21.

  An experiment for evaluating each static elimination capability of the X-ray static elimination device 20 of the first embodiment described above, the corona discharge static elimination device, and the conventional X-ray static elimination device with the film static elimination evaluation device 100 shown in FIG. The results of the evaluation experiment are shown in comparison with FIG. 4 is substantially the same as that shown in FIG. 9, but in FIG. 4, the X of the first embodiment having the self-discharge electrode 30 grounded together with the casing 21. The state which is evaluating the wire-type static elimination apparatus 20 is shown. In this evaluation experiment, the outputs of the X-ray static eliminator 20 of the first embodiment, the corona discharge static eliminator, and the conventional X-ray static eliminator are substantially the same (similar to each other). The X-ray type static eliminator 20 and the corona discharge type static eliminator of the embodiment were evaluated both when the power was turned on and when it was turned off. The static elimination distance was fixed at 5 cm. In this experiment, the charge voltage before static elimination was set to -43 kV.

  As shown in FIG. 5, when the corona discharge type static eliminator is turned on (broken line connecting black triangles in the figure), the charge voltage after static elimination, which was −2 kV at a film conveyance speed of 10 m / min, is If it exceeds 200 m / min, it increases to -9 kV, and a gradual decrease in the static elimination capability accompanying an increase in the film conveyance speed is observed.

  When the corona discharge type static eliminator is turned off (dashed line in the figure), the charged voltage after static elimination, which was about -9 kV at a film conveyance speed of 10 m / min, is -15 kV at over 200 m / min. Increase to. As described above, even if the power is turned off, a certain static elimination capability is maintained, but as the film transport speed increases, the static elimination capability gradually decreases.

In the conventional X-ray static elimination apparatus (solid line connecting black circles in the figure), the static elimination capability rapidly decreases as the film speed increases, and the negatively charged film cannot be sufficiently eliminated.
This is the same as the result shown in FIG.

  On the other hand, when the X-ray type static eliminator of the embodiment is X-ray ON (in the figure, a solid line connecting black circles, Example 1 (X-ray type with self-discharge)), the film conveyance speed is 10 m / min. Even if the charge voltage after static elimination, which was 0 V in Fig. 1, exceeds 200 m / min, it increases only to -7 kV, and the decrease in static elimination capability accompanying the increase in film transport speed is caused when the corona discharge type static elimination device is turned on. Even more gradual than.

  Further, when the X-ray static eliminator of the embodiment is X-ray OFF (solid line connecting ○ in the figure), the charge voltage after static elimination is about −12 kV at a film conveyance speed of 10 m / min, and the corona It is slightly higher than about −9 kV when the discharge type static eliminator is turned off (broken line connecting Δ in the figure). However, in the vicinity of exceeding 120 m / min, the charged voltage after static elimination is smaller when the X-ray type static eliminator of the embodiment is OFF than when the corona discharge type static eliminator is OFF. Furthermore, at 200 m / min, it becomes -13 kV, and when the corona discharge type static eliminator is turned off, it is about -15 kV, whereas the charging voltage after static elimination is as low as 2 kV.

Thus, it was found that when the X-ray of the X-ray static eliminator of the embodiment is OFF, the charging voltage is almost constant after static elimination regardless of the film conveyance speed.
Thus, according to the X-ray type static eliminator of 1st Embodiment, when X-ray | X_line was ON, ie, in the case of normal static elimination work, it turned out that it exceeds a corona discharge type static eliminator by static elimination capability.

  This is because, in the X-ray type static eliminator of the first embodiment, the housing 21 that houses the X-ray tube 1 is insulated from the X-ray tube 1 and grounded, and in the vicinity of the opening 23 of the housing 21. Is provided with the self-discharge electrode 30 at the same potential as that of the casing 21 (that is, the ground potential of 0 V), so that the static elimination object and the self-discharge electrode according to the difference between the potential of the static elimination object and the ground potential. This is considered to be due to the phenomenon in which the charge is transferred to 30 and the charge removal object is discharged, that is, the self-discharge phenomenon occurs.

  As shown in FIG. 5, the reason why the X-ray type static eliminator of the first embodiment is superior to the corona discharge type static eliminator is considered to be due to the above reason.

  In addition, the X-ray type static eliminator of the first embodiment is superior to the corona discharge type static eliminator as described above in the film static eliminator 100 as shown in FIG. The fact that it is a result obtained by an experiment is a fact that has not been known so far, and is considered to be worthy of special mention. That is, regardless of the principle, under the condition that the charge is removed while moving the resin film 103 that is easily charged, X-rays are emitted and zero potential is applied rather than the charge removal method in which ions generated by corona discharge are blown. The method of removing electricity by causing self-discharge with the self-discharge electrode 30 is more effective.

3. FIG. 6 shows a corona discharge type static eliminator (a broken line connecting x when the power is ON) and an X-ray type static eliminator of the second and third embodiments ( When both are X-rays ON, Example 3 is a solid line connecting black triangle marks, Example 4 is a solid line connecting black triangle marks, and a conventional X-ray static eliminator (when X-rays are ON, black circle marks) It is a graph which compares and shows the result of the evaluation experiment which evaluated each static elimination capability of the solid static electricity line) with the film static elimination evaluation apparatus 100. FIG.

  In Embodiment 2 (Example 2), as shown in FIG. 3B, the self-discharge electrode 31 has a sawtooth shape, and is sharper than the needle-like self-discharge electrode 30 of the first embodiment. Since the degree of sharpness is slightly smaller, the neutralization capability is slightly lower than that of the first embodiment or the corona discharge type neutralization device (when the power is turned on), but the neutralization capability is almost the same as these. Yes.

  Further, in the third embodiment (Example 3), as shown in FIG. 3C, the self-discharge electrode 32 has a brush shape, which is different from the needle-shaped self-discharge electrode 30 of the first embodiment. Since the degree of sharpness (sharpness) is large, the static elimination capability is higher than that of the first embodiment and the corona discharge type static elimination device (when the power is turned on).

  As described above, according to each embodiment of the present invention, there is no X-ray type specific effect that cannot be obtained with a corona discharge type static eliminator, that is, there is no problem of dust adhesion due to blowing, and the discharge needle that applies a high voltage is used. In addition to these effects, there is not only the problem of wear and generation of debris, but also the practically advantageous effect that there is no complexity of controlling the frequency of the AC high voltage applied to the discharge needle. In particular, when a film that is easily charged and that is easy to be charged is targeted for static elimination, the static elimination effect can be greatly improved compared to the conventional X-ray type, and also compared to a corona discharge type static elimination device. Thus, an excellent effect of obtaining an equivalent or higher static elimination effect can be obtained.

DESCRIPTION OF SYMBOLS 1 ... X-ray tube 3 ... Container part 4 ... Board | substrate 5 ... X-ray transmissive window 6 ... Window part 7 ... X-ray target 9 ... Cathode 10, 11 ... Control electrode 20 ... Static elimination apparatus 21 ... Case 23 ... Opening part 30, 31, 32 ... Electrode for self-discharge 100 ... Film static elimination evaluation apparatus 103 ... Film as static elimination object

Claims (3)

In a static eliminator that performs static elimination by irradiating a static elimination object with X-rays,
An X-ray tube having an X-ray transmission window for irradiating X-rays to the outside;
A housing that houses the X-ray tube and includes an opening corresponding to the X-ray transmission window;
A self-discharge electrode provided in the vicinity of the opening of the housing and grounded;
A static eliminator characterized by comprising: The X-ray tube is
A radiopaque substrate having a window formed thereon;
An X-ray transmissive window provided to close the window from the outer surface side of the substrate;
An X-ray target provided on the window from the inner surface side of the substrate;
A flat box type container part attached to the inner surface side of the substrate and the inside of which is in a high vacuum state,
A linear cathode that is provided inside the container and emits electrons that collide with the X-ray target;
A control electrode provided between the cathode and the X-ray target for controlling electrons emitted from the cathode;
The static eliminator according to claim 1, comprising: The static eliminator according to claim 2, wherein the casing and the self-discharge electrode are made of stainless steel, and an insulating member is provided between the X-ray tube and the casing.

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