JPS63304147A - Method and device for inspecting non-destructively foreign matter - Google Patents

Abstract

PURPOSE:To detect with high accuracy a foreign matter, etc., in an object to be inspected, by forming an electrophotographic latent image of the object to be inspected, on an X-ray electrophotographic recording body, converting this latent image to a powder image and converting it to an electric signal, thereafter, displaying it as an X-ray tomographic image on a monitor. CONSTITUTION:An object to be inspected 6 is stored in a containing case 4, thereafter, an X-ray electrophotographic recording body 11 is moved in the direction as indicated with an arrow A, electrified by a corona electrifier 12, and stopped at the lower part of the containing case 3. Subsequently, by driving an X-ray generating device 1, X-rays are radiated to the object to be inspected 6, and by its transmission X-rays, an electrophotographic latent image is formed on the recording body 11. Next, this recording body 11 is moved to the position of a developing device 16 and brought to a development processing, and converted to a visible powder image. Thereafter, this developed recording body 11 is moved to the position of an image read part 18, said visible powder image is converted to an electric signal by a photoelectric converting means 54, and its converting signal is inputted to a CRT display device 55. An inspector decides whether the object to be inspected is acceptable or not, by observing visually an image displayed on this display.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a non-destructive foreign matter inspection method and device, and in particular, it relates to a method and device for non-destructive foreign matter inspection, and in particular to pasty foods such as ham or kamaboko, molded products made of synthetic resin or rubber, or encapsulated electronic components. The present invention relates to a non-destructive foreign object inspection method and device that are optimal for detecting foreign objects, voids, cracks, etc. that are inconveniently mixed inside foods or products that cannot be detected by external inspection in electronic products such as electronic products.

[Prior Art] Conventionally, ultrasonic inspection methods, electromagnetic inspection methods, soft X-ray inspection methods, and the like have been known as non-destructive foreign object inspection methods, and some of them have been commercialized and put into practical use. Among them, for internal inspection of foods such as ham, there is a pulse eco method using ultrasonic waves, a fluorescent method using X-rays, and an EXICO method.
Several inspection devices based on the N-panel system or the II camera (X-ray fluorescence intensification camera) system have been implemented.

Food products such as ham must be inspected more thoroughly than industrial products, as not only foreign substances are mixed in, but even minute air bubbles can affect their quality. Products containing such substances must be reliably checked and removed at the inspection stage.

[Problems to be Solved by the Invention] By the way, the apparatus using the conventional method described above still has some problems and is not satisfied as a sufficient inspection apparatus. For example, an ultrasonic pulse eco one-type device has a slow inspection speed, and is appropriately effective as an offline inspection device, but is not suitable as an online inspection device at a factory established in Sui. Also, fluorescent method, EXI
The CON panel type and II camera type devices still have the problem that it is difficult to identify foreign objects such as wood chips, plastic, or minute bubbles due to the unique internal structure of the ham.

The present invention has excellent ability to identify foreign objects even in the unique internal structure of hams, etc., and has the ability to detect wood chips, which were difficult to detect with conventional devices.
A non-destructive foreign object inspection method and device that can detect not only foreign objects such as plastic but also minute air bubbles, as well as the flow direction of meat tissue and the distribution of muscle and fat layers within a ham. The purpose is to provide

[Means for Solving the Problems] The method according to the present invention forms an electrophotographic latent image corresponding to an X-ray transmission image of an object to be inspected on an X-ray electrophotographic recording medium, and develops the latent image. The present invention is characterized in that after forming a visible powder image, the powder image is optically read and converted into an electrical signal, and an X-ray transmitted image of the object to be inspected is displayed on a monitor based on this electrical signal.

Xi! The formation of an electrophotographic latent image on a 1lffi child photographic recording medium is performed, for example, by applying a primary charge of a specific polarity to the X-ray electrophotographic recording medium, and then irradiating an X-ray transmission image transmitted through the subject and simultaneously applying a reverse polarity charge. This can be carried out using the KIP method, in which a latent image corresponding to an X-ray transmission image is formed by applying radiation, or the xeroradiography method, in which an image is formed by irradiating a transmission image. By using the image forming method using these X11a"?4 photographic recording bodies, it is possible to obtain a clear X-ray transmission image due to the etch effect unique to electrophotography, and after visualizing this, it is possible to The information is read by a sensor, photoelectrically converted, displayed on a monitor, and provided for internal inspection.

An apparatus embodying this method emits an X-ray transmission image of the object to be inspected from the back side of an X-ray electrophotographic recording medium charged to a specific polarity, and at the same time applies a reverse polarity or AC electric field to the transmission image. A latent image forming means for forming a corresponding electrostatic latent image, a developing means for applying developing powder to the latent image to form a visible powder image, and optically reading this visible image and converting it into an electrical signal. An apparatus is provided that includes a photoelectric conversion means for generating an image and a monitor for displaying an image based on the electric signal.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 designates an X-ray generator having an X-ray tube 2 on the upper side and an X-ray irradiation port 3 on the lower surface. Below the X-ray irradiation port 3, acrylic resin or carbon fiber reinforced resin (
A test object storage tray 4 made of a material with relatively high X-ray transmittance such as C-FRP and having an open top is arranged, and a test object 6 to be inspected is placed inside the storage tray 4. It can be accommodated freely. The storage tray 4 is constructed to be able to be pulled out in a direction perpendicular to the plane of the drawing, and a door lock shutter is provided at the entrance and exit portion of the storage tray to prevent leakage of X-rays to the outside.

A discharge device 8 is arranged below the storage tray 4 with a space 7 in between. In the space 7, an X-ray electrophotographic recording medium 11, which is disposed horizontally movably by a rail device or a chain device 9, is transferred and guided according to a predetermined sequence control. Along the rail device 9, in other words, along the moving path of the recording medium 11, a primary corona charger 12, a uniform exposure unprinter 17, and an image reading section 18 are operatively arranged in order from the discharge device 8. The developing device rr 116 and the cleaner 17 are each provided movably in the vertical direction (direction toward and away from the moving path of the recording medium 11), as will be described later.
In this state, it is located at a lower position, and only when activated, it moves upward and acts on the recording medium 11. For convenience of explanation, the developing device 16 and the cleaner 17 are shown in their operating positions in FIG. Further, the inspection apparatus main body 10 that houses the above-mentioned apparatus and recording medium is in the form of a shield box that prevents external diffusion of X-rays.

In this example, the recording body 11 is formed into a plate shape, and is made of carbon fiber reinforced resin (C-
It has a multilayer structure in which a substrate such as FRP (FRP), a protective film layer, an electrode layer, an insulating layer, a photoconductor layer, and a surface insulating layer are sequentially laminated.

The photoconductor layer may have a multilayer structure including a carrier generation layer, a carrier movement layer, and a carrier trapping layer, which are composed of an appropriate combination of selenium and selenium telluride in addition to an intermediate layer structure of selenium or a selenium compound. good. The surface insulating layer of the recording body 11 is made of
It is white or light colored.

The recording medium 11 is held by a gripper (not shown) of the chain device 9 with the surface insulating layer facing downward, and is on standby at a position above the developing device 16.

After storing the inspection object 6 in the latent image forming process storage box 4, when the operation switch of the apparatus is turned on, the chain device 9 is driven and the recording medium 11 is moved in the direction of the arrow.

During movement, the recording medium 11 is biased from the surface insulating layer side by an AC corona discharger 11 and a uniform exposure chamber 13 to remove static electricity, and then, under this uniform exposure, a primary corona charger 12 is applied.
It is charged to a specific polarity, for example, positive polarity, and stops at a position below the storage box 4, that is, at a position in the space 7. Around this time, the AC corona discharger 14 and the secondary corona charger 12 are deenergized.

Due to this -order corona charging, many chirelia in the photoconductor layer of the recording medium 11 are eventually captured by the photoconductor layer's traps in response to the electric field, resulting in sustained internal polarization (P, T , P, ), P, 1. P,
Forms a charge layer.

Next, the X-ray generator is energized, and an X-ray image transmitted through the object to be inspected in the storage box is irradiated from the substrate side of the recording medium.

Simultaneously with this irradiation, a charge with a polarity opposite to the primary corona charge (negative polarity) is applied from the surface insulating layer side by the discharge device 8.

As a result, in the portion of the recording body 11 onto which the X-rays are projected, the X-rays that have passed through the substrate excite the photoconductor layer, and the P, 1, . P, most of the charge is released and a large number of free charges are generated inside the photoconductor layer. As a result, most of the applied charges of opposite polarity are concentrated on the surface insulating layer of positive polarity, so that the surface charges charged in the previous process recombine and disappear, and at the same time new charges of negative polarity are generated. charged. On the other hand, for the part that is not exposed to X-rays, P, 1. P,
Since the charge is not rapidly released, the charge remains retained from the previous process. In this way, an electrostatic latent image corresponding to the X-ray transmission image is formed.

In order to uniformly charge a stationary recording medium over a relatively wide area, a device shown in FIG. 3 can be used as the discharge device 8. As shown in the figure, the discharge device 8 includes a box 20 that is open at the top.
, a chassis 21 disposed within the box body 20 and having an opening large enough to cover the entire image forming surface of the recording medium 11 at the top; and a conductive substrate 22 disposed within the chassis 21 and grounded. , a plurality of corona discharge wires 23 that are insulatively supported with respect to the substrate 22 and arranged at approximately equal intervals in the horizontal direction; It is composed of a plurality of grid control electrodes 24 arranged at approximately equal intervals. Chassis 2
There are two pairs of parallel brackets 2 on both sides of the lower end of 1.
5 and 26 are provided, and to these brackets 25 and 26, two pairs of arms 27 and 28, one end of which is pivotally connected to both sides of the inside of the box body 20, and the other end of the arm 27, 28 are pivotally connected to the brackets 25 and 26.
8 is driven through a suitable transmission means, and reciprocates in the direction of arrow B in the figure so that the discharge electrode 23 remains parallel to the surface of the recording medium and moves at a constant speed.

This movement is performed in synchronization with the activation of the X-ray generator 1, that is, the time of X-ray irradiation, and along with this movement, the corona discharge wire 23 is connected to an appropriate high-voltage power source to perform corona discharge and discharge the recording material. 11 is given a negative polarity charge.

Referring again to FIG. 1, the recording medium 11 on which the latent image has been formed then moves in the direction opposite to the arrow, and at this time, the exposure lamp 1
3 is energized to uniformly expose the recording medium, increase the latent image contrast, and complete the latent image formation process.

Developing Step The recording medium on which the latent image has been formed as described above is stopped at the position of the developing device 16.

As shown in FIG. 4, the developing device 16 has a box-shaped developing chamber 31 with a developing opening 30 at the top, and the chamber has a suitable rail means such as a slide bearing extending vertically on the outer surface of the chamber. It is supported so as to be movable in the vertical direction as seen in the figure with respect to the main body of the apparatus, and is connected to a drive means (not shown) such as a chain drive, and moves up and down according to a predetermined sequence control.

The developing chamber 31 is made of a grounded conductive material, and as the chamber moves upward, an electrically insulating backing provided along the periphery of the opening 30 of the chamber is applied to the recording medium 11 that is stopped above the developing chamber. Due to this, the opening 30 is closed by the recording body 11 and the recording body 11 is closed.
The imaging surface (surface insulating layer) of is exposed in the development chamber.

A plurality of nozzles 33 and 34 for blowing out air (compressed air) are provided in parallel on both sides of the developing chamber 31, respectively. One nozzle 33 is equipped with a flexible vibrator 35 for air supply, and the nozzle 34 is equipped with a flexible vibrator 36.
are connected to an air tank 38 via a common solenoid valve 37.

The air tank 38 is configured to be operated by a compressor 39.

In front of the nozzle 33, a bristle brush roller 41 having a roll surface made of a short-bristle material such as velvet and having an appropriate width is provided at approximately the center of the developing chamber 31 in the width direction. The bristle brush roller 41 is configured to rotate in the direction shown by arrow C at a predetermined rotational speed, and below it is a leveling roller 42 of approximately the same width that rotates in contact with the bristle brush roller 41. It is provided. The surface of the leveling roller 42 is configured similarly to the bristle brush roller 41, and is configured to rotate in the direction shown by the arrow.

Further, a toner hopper 44 having an arcuate cross section is provided at the lower end of one side of the developing chamber 31 . A mesh 45 that can supply toner powder to the outside is provided at approximately the center in the width direction of the arcuate wall portion of the toner hopper 44 and spans approximately the same width as the leveling roller 42. The leveling roller 42 is provided so as to rotate while rubbing against the net mesh 45 with relatively weak pressure. on the other hand. Inside the toner hopper 44, a plurality of rotary blades 46 are provided around a shaft 48 so as to move along the arcuate inner wall of the toner hopper 44 with their tips touching each other. The tip of the rotary blade 46 carries the toner powder in the toner hopper 44 to the mesh 45 and
bristles 4 to suitably feed the outside of the hopper through 5
7 is provided. Rotation W46 is configured to rotate in the direction shown by arrow E.

Next, the operation of the developing device will be explained.

First, when the recording medium 11 on which the electrostatic latent image has been formed is positioned above the developing device with the image forming surface facing downward, a drive means (not shown) is activated to move the chamber 31 upward, and the recording medium 11
stops when the opening 30 is closed. Next, the rotor blades in the toner hopper containing the toner powder are rotated.
The toner powder is conveyed to the net mesh 45 via the bristles 47 at the tip of the rotary blade 46. The compressor 39 is operated on (or before and after) the toner powder carried to this mesh, and compressed air is sent to the vibrator 35.36 via the air tank 38 and the solenoid valve 37, and is injected from the nozzle 33.34. do. The electromagnetic valve 37 is repeatedly opened and closed an appropriate number of times during development of one recording medium, and compressed air is injected intermittently accordingly. The toner powder adhering to the bristle brush roller 41 is blown away by the air jetted from the air nozzle 33.
The developing chamber 31 is filled with a mist. Also, nozzle 3
The air ejected from the nozzle 34 provided on the side opposite to the nozzle 3 has the function of uniformly filling the developing chamber 31 with toner powder carried by the air ejected from the nozzle 33. When the toner powder is uniformly filled with the air ejected from the bristle brush roller 33 in the form of mist, the toner powder is deposited on the image forming surface of the recording medium 11 depending on the surface potential of the electrostatic latent image. It adheres and develops according to the conditions. When the development is completed, the air injection from the nozzle 33 is stopped, and the bristle brush roller and leveling roller are stopped.

A positive image is formed by applying a (+) back bias to the recording medium during development, and a negative image is formed by applying a (-) back bias.

Next, the toner powder floating in the developing chamber is forced to pass through the duct 49 to the filter box 51.
to be collected. At the same time or before or after this, the cleaner 52
is moved in the direction indicated by arrow F to remove the toner powder accumulated on the bottom surface of the developing chamber 31 and drop it into the toner reservoir.

After these series of operations are completed, the developing chamber is lowered and separated from the recording medium, and the developing process is completed.

After the photoelectric conversion step and the development step, the recording medium 11 moves in the direction opposite to the arrow,
It is located in the image reading section 18. When the recording medium 11 is moved, the cleaner 17 is in a lowered position, and the recording medium 11 is moved.
It does not affect 1. The image reading unit 18 includes a fluorescent lamp 51 as an exposure light source for illuminating the image forming surface of the recording medium 11, and a fluorescent lamp 51 for guiding reflected light from the recording medium 11 illuminated by the fluorescent lamp 51 to an imaging lens 52. Half mirror 53 and
A photoelectric conversion means 54 consisting of a solid-state image pickup device using a charge coupled device (COD) or the like arranged in a matrix or an ITV camera that photoelectrically converts the optical image formed by the imaging lens 52 and outputs an electric signal. include. The photoelectrically converted signal output from the conversion means 54 is sent to a monitor 55 such as a CRT display, where the
A line-transparent image is displayed. The inspector can visually check the image displayed on the monitor to determine whether the object to be inspected passes or fails.

On the other hand, the output from the conversion means 54 is displayed on the monitor 55 after being subjected to appropriate image processing such as differential processing, high frequency processing, Laplacian processing, and/or r-characteristic processing, in addition to the above-mentioned direct display. You can do it like this. For example, the fifth
In the illustrated example, the output from the converting means 54 is sent to a shading cancerer 56, where it is corrected for image shading such as uneven illumination and uneven development, and then sent to a monitor. Next, the image processing board 57 removes noise,
Concentration gradation conversion, foreign matter extraction, shape analysis, etc. are performed. Output information from the board 57 is stored via a multipath interface 58 in a storage means 59 such as a computer containing image processing software. This information is read out as needed and displayed on the monitor 61, or a hard copy is created by the external printer 62.

The recording medium 11 that has finished reading the cleaning and static elimination process moves in the direction of the arrow and stops above the cleaner 17.

At this time, the cleaner 17 located below rises and engages with the recording medium 11 to remove toner powder from the surface of the recording medium and clean the surface. As the cleaner 17, for example, a rotating bristle brush type cleaner or a rubber blade type cleaner is adopted.

After cleaning is completed, the cleaner moves downward again, and then the recording medium 11 moves in the direction of the arrow. During this movement, the recording medium 11 is irradiated with light from the exposure lamp 13 and subjected to corona discharge from the AC corona discharger 14, so that static electricity is removed from the recording medium 11.

The recording medium 11 moves further, is reversed at the position of the discharge device 8, and is again subjected to the action of the exposure lamp 13 and the AC corona discharger 14 for removal.

After the power is completely turned off, it stops at a position above the developing device 16 and waits for the next image formation.

[Effects of the Invention] As described above, according to the present invention, by applying X-ray electrophotography, it is possible to detect minute metal pieces, foreign matter pieces, especially wood pieces, plastic pieces, or minute pieces that are difficult to recognize with conventional methods or devices. It is also possible to detect voids.

[Brief explanation of drawings]

FIG. 1 shows a schematic diagram of a non-destructive foreign object inspection according to the present invention.
FIG. 2 is a sectional view of an example of the XII electrophotographic recording medium used in the device shown in FIG. 1, FIG. 3 is a schematic diagram showing the discharge device of the device shown in FIG. FIG. 5 is a schematic diagram showing the electrical processing section of the apparatus of FIG. 1... X-ray generator, 6... Inspection object, 8...
Discharge device, 11... X-ray electrophotographic recording medium, 12...
- Corona charger, 16... Developing device, 17... Cleaner, 18... Image reading section, 54... Photoelectric conversion means, 55... Monitor Figure 1 Figure 2 Figure 8

Claims (10)

[Claims] (1) Form an electrophotographic latent image corresponding to the X-ray transmission image of the object to be inspected on an X-ray electrophotographic recording medium, develop the latent image into a visible powder image, and then convert the powder image into a visible powder image. A non-destructive foreign object inspection method that is characterized by optically reading the information, converting it into an electrical signal, and displaying an X-ray transmission image of the object to be inspected on a monitor based on this electrical signal. (2) An electrostatic latent image corresponding to the transmitted image is created by irradiating an X-ray transmitted image of the object to be inspected from the back side of an X-ray electrophotographic recording medium charged to a specific polarity and simultaneously applying a reverse polarity or alternating current electric field. a latent image forming means for forming a latent image, a developing means for applying developing powder to the latent image to form a visible powder image, a photoelectric conversion means for optically reading the visible image and converting it into an electrical signal; A non-destructive foreign matter inspection device comprising: a monitor that displays an image based on the electrical signal. (3) A non-destructive foreign object inspection device according to claim 2, wherein the electric signal is subjected to image processing and then displayed on a monitor. (4) In the device according to claim 2 or 3, the device further includes storage means for storing the electrical signal or the image-processed signal, and the storage means stores the electrical signal or the image-processed signal. A non-destructive foreign matter inspection device, characterized in that the X-ray transmission image can be displayed on a monitor by reading out information. (5) A non-destructive foreign matter inspection apparatus according to claim 4, further comprising a printer that creates a hard copy of an X-ray transmission image based on the stored information from the storage means. (6) In the apparatus according to claim 2, the X-ray electrophotographic recording medium is a multilayer structure in which a protective film layer, an electrode layer, an insulating layer, a photoconductor layer, and a surface insulating layer are sequentially laminated on a substrate. A non-destructive foreign matter inspection device characterized by a structure consisting of: (7) A non-destructive foreign matter inspection device according to claim 6, wherein the surface insulating layer is white or light-colored. (8) An X-ray electrophotographic recording medium in which a photoconductive layer is formed on a conductive layer is charged to a specific polarity, and then an X-ray transmission image of the object to be inspected is irradiated to form an electrostatic latent image corresponding to the transmission image. a developing means for applying developing powder to the latent image to form a visible powder image; a photoelectric conversion means for optically reading the visible image and converting it into an electrical signal; A non-destructive foreign object inspection device characterized by comprising a monitor that displays an image based on a signal. (9) A non-destructive foreign matter inspection device according to claim 8, wherein the X-ray electrophotographic recording medium has a white or light-colored image forming surface. (10) Passage (9) for reciprocating the plate-shaped X-ray electrophotographic recording medium
), opposite the X-ray generator (1), a reverse polarity discharge device (8), a specific polarity corona charger (12), a static eliminator (13, 14), a developing device (16), and a cleaner (17).
), image reading devices (18) are arranged, and these devices are sequentially operated in synchronization with the movement of the recording medium.