JP2018048895A - Image detection device and fabrication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique which can precisely detect image defects, and which can realize reduction in size and weight of an image detection device.SOLUTION: An image detection device includes: a linear illumination lamp for irradiating a surface of an imaging object with light at an angle of 45 degrees or less; a linear image sensor arranged parallel to the linear illumination lamp; and an erecting equal-magnification optical system for guiding the light reflected or scattered on the surface of the imaging object to the image sensor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image detection apparatus and a modeling apparatus.

  A modeling apparatus that forms a three-dimensional model by stacking a large number of layers has been attracting attention. This type of additive manufacturing technology is called additive manufacturing (AM), three-dimensional printer, rapid prototyping (RP), or the like. Various modeling methods have been proposed for additive manufacturing technology. Japanese Patent Application Laid-Open No. H10-228561 discloses a modeling method that applies an electrophotographic process in which image data is formed into a sheet and the sheets are stacked. Patent Document 2 discloses a film defect detection method.

JP 2003-053846 A JP 2014-211141 A

In a modeling method such as Patent Document 1 in which a slice image is converted into a particle image using a resin material and laminated as a sheet-unit material image, the material image is formed due to transfer failure when the particle image is formed and when the material image is transferred to a transfer body. There is a possibility that a defective part is generated. When a defective portion occurs, there is a concern that the material image of the next layer cannot be satisfactorily contacted and the lamination cannot be continued. In Patent Document 1, there is no description about an image defect, and there is no description about correction when an image defect occurs. In addition, if a thin layer is formed as the accuracy in the stacking direction increases, the light transmittance of the material image increases and the reflected light from the transfer body is transmitted, resulting in a decrease in contrast, and image acquisition with a general optical sensor. There is concern that it will be difficult.
In Patent Document 2, a film defect is detected by a defect detection unit including an illumination unit, an imaging unit, an illumination optical path changing unit, and an illumination light intensity control unit. The illumination means uniformly illuminates the width direction of the film, and the imaging means is provided on the opposite side of the illumination means with respect to the film, and images the illuminated film surface. The illumination light path changing means is configured by combining a plurality of mirrors, and changes the optical path of the illumination light emitted from the illumination means so as to enter the imaging means. As in Patent Document 2, the defect detection means using the reduction optical system requires a plurality of cameras when the reading width becomes large, and complex processing such as output image combining processing and overlapping pixel connection processing between adjacent cameras is required. Processing is required. Furthermore, in order to increase the overall optical path length, a large optical area is required, and when the weight of the defect detection means is increased, there is a concern that the cost will increase.

  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to provide a technique capable of more reliably detecting an image defect and realizing a reduction in size and weight of an image detection apparatus. To do.

The first aspect of the present invention is:
Linear illumination that irradiates light at an angle of 45 degrees or less with respect to the surface of the imaging object;
A line-shaped image sensor arranged in parallel with the line-shaped illumination;
An erecting equal-magnification optical system that guides light reflected or scattered by the surface of the imaging object to the image sensor;
An image detecting apparatus is provided.

The second aspect of the present invention is:
A modeling apparatus for producing a three-dimensional object by laminating material images made of modeling materials based on three-dimensional shape data of a three-dimensional model,
An image forming unit that forms the material image based on slice data generated from the three-dimensional shape data;
The above-described image detecting device for detecting the material image;
The modeling apparatus characterized by having is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which can detect an image defect more reliably and can implement | achieve size reduction and weight reduction of an image detection apparatus can be provided.

The figure which shows typically the structure of the modeling apparatus which concerns on 1st Embodiment. The figure which shows typically the fusion | melting lamination | stacking of a material image. The figure which shows typically the defect image generation of a material image. The figure for demonstrating a bright field and a dark field. The schematic diagram which shows the illumination optical system for acquisition of a material image. The figure for demonstrating the difference of a reduction optical system and a 1x contact | adherence optical system. The block diagram of a modeling controller. The control block diagram of image defect acquisition and recovery. The figure explaining the defect image comparison algorithm of a control block diagram. The flowchart 1 of the defect image acquisition of a control block diagram, and a recovery process. The flowchart 2 of the defect image acquisition of a control block diagram, and a recovery process. The figure which shows typically the structure of the sensor unit which concerns on 2nd Embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described with reference to the drawings. However, unless otherwise specified, various control procedures, control parameters, target values, etc., such as dimensions, materials, shapes, and relative arrangements of the members described in the following embodiments are described in the present invention. It is not intended to limit the scope of the above to only those.
The present invention is suitable for incorporation into a modeling apparatus employing a layered modeling technique (AM technique), that is, a technique for producing a three-dimensional object (three-dimensional object) by arranging modeling materials in two dimensions and laminating them in layers. The present invention relates to a simple image detection apparatus.
As the modeling material, various materials can be selected according to the application, function, purpose, etc. of the three-dimensional object to be produced. In this specification, a material constituting a three-dimensional object for modeling is referred to as “structural material”, and a portion formed of the structural material is referred to as a structure. A material that constitutes a support body (for example, a column that supports the overhang portion from below) for supporting the structure being manufactured is referred to as a “support material”. When it is not necessary to distinguish between the two, the term “modeling material” is simply used. As the structural material, for example, a thermoplastic resin such as PE (polyethylene), PP (polypropylene), ABS, PS (polystyrene), and PC (polycarbonate) can be used. As the support material, a material having thermoplasticity and water solubility can be preferably used in order to simplify the removal from the structure. Examples of the support material include carbohydrates, polylactic acid (PLA), PVA (polyvinyl alcohol), and PEG (polyethylene glycol).

Further, in this specification, digital data obtained by slicing three-dimensional shape data of a stereo model to be produced into a plurality of layers along the stacking direction is referred to as “slice data”. The slice data is generated by adding information such as support material data as necessary. A layer (image for one layer) formed of a modeling material based on slice data is referred to as a “material image”. A “material image” is a layer of particles formed by combining one or more material images depending on the type of modeling material used. In addition, the image of the particle unit formed with a modeling material based on slice data may be called a “particle image”.
A three-dimensional model (that is, a three-dimensional object represented by three-dimensional shape data given to the modeling apparatus) to be manufactured using the modeling apparatus is referred to as a “modeling object”. A three-dimensional object (three-dimensional object) produced (output) by the modeling apparatus is referred to as a “modeled object”. In the case where the modeled object includes the support body, a portion excluding the support body becomes a “structure” constituting the modeled object. In addition, a direction orthogonal to a laminated surface 49a of the stage 49 described later is referred to as “vertical direction”. Further, in the vertical direction, a direction toward the upper part of the paper surface in FIG. 1A is an upward direction, and a direction toward the lower part of the paper surface in FIG.

<First Embodiment>
(Configuration of modeling equipment)
With reference to FIG. 1A and 1B, the structure of the modeling apparatus 1 which concerns on 1st Embodiment is demonstrated. FIG. 1A is a diagram schematically illustrating the configuration of the modeling apparatus 1 according to the present embodiment. FIG. 1B is a diagram schematically illustrating an enlarged configuration of the material image detection portion.

  The modeling apparatus 1 of the present embodiment includes an outline, a control unit, an image forming unit, and a stacking unit. The control unit is a component that performs processing for generating slice data of a plurality of layers from the three-dimensional shape data of the modeling target, control of each unit of the modeling apparatus 1, and the like. The control unit includes a control unit 60, an image generation controller 10, a modeling controller 70, a plurality of motors 47 to 48, a sensor unit 90 as an image detection device, and the like. The image forming unit is a component that forms a material image 50 for one layer made of a modeling material based on slice data of each layer. The image forming unit includes a laser scanner (exposure device) 20, a cartridge (process cartridge) 30, a transfer roller 41, and the like. The stacked portion is a component that forms a three-dimensional object having a three-dimensional structure by sequentially stacking and fixing a plurality of material images 50 formed in the image forming portion. The stacking unit includes a transfer body 42, a heater plate 43, a stage 49, a cleaner (discarding unit) 46, and the like.

(Control part)
The control unit 60 has a function of converting the three-dimensional shape data of the modeling target into modeling slice data, a function of outputting slice data of each layer to the image generation controller 10, a function of managing the layered modeling process, and the like. The control unit 60 can be configured by, for example, mounting a program having these functions on a personal computer or an embedded computer. As the three-dimensional shape data, data created by a three-dimensional CAD, a three-dimensional modeler, a three-dimensional scanner, or the like can be used. The format of the three-dimensional shape data is not limited, but for example, polygon data such as STL (Stereolithography) can be preferably used. As the format of the slice data, for example, multi-value image data (each value represents a material type) or multi-plane image data (each plane corresponds to a material type) can be used.

  The image generation controller 10 has a function of controlling an image forming process in the image forming unit based on slice data input from the control unit 60 and a control signal input from the modeling controller 70. Specifically, the image generation controller 10 performs resolution conversion and decoding processing of slice data, control of the image writing position and timing by the laser scanner 20, and the like. In addition, the image generation controller 10 may have the same function as a printer controller built in a general laser printer (2D printer).

  The modeling controller 70 has a function of performing mechatronic control of the modeling apparatus. The drive system includes a transfer roller motor 47 that rotationally drives the transfer roller 41 and a stage drive motor 48 that moves the stage 49. The sensing system includes a sensor unit 90 that detects the material image 50. Details of the role of these sensors will be described later.

In FIG. 7, an example of the circuit block of the modeling controller 70 is shown. The modeling controller 70 includes a CPU 71, a memory 72, an interface 73, a UI unit 74, a motor drive circuit 75, a motor driver 76, a sensor detection circuit 77, a sensor interface 78, other IO circuits 79, a heater circuit 80, and an IO interface 81. . A transfer roller motor 47 and a stage drive motor 48 are connected to the motor driver 76. The sensor interface 78 is connected to a rotary encoder detection sensor (not shown), a cover open detection switch of the modeling apparatus, a home position sensor of the stage 49, and the like. A heater and a thermocouple in the heater plate 43 are connected to the heater circuit 80. Drive signals for the contact line sensor 91, the illumination light source 95, the cleaner 46, and the like are connected to the IO interface 81. Here, the illumination light source 95 corresponds to linear illumination that irradiates light at an angle of 45 degrees or less with respect to the surface of the imaging target (in the present embodiment, the material image 50). The contact line sensor 91 corresponds to a line-shaped image sensor arranged in parallel with the line-shaped illumination. Here, the contact line sensor 91 and the illumination light source 95 are provided to be linear on the surface of the transfer body 42 with respect to the direction orthogonal to the traveling direction of the transfer body 42.
In the present embodiment, the control unit 60, the modeling controller 70, and the image generation controller 10 are configured by separate controllers. However, these functions may be configured by a single controller.

(Image forming part)
The image forming unit is a unit that forms a material image for one layer made of a modeling material using, for example, an electrophotographic process. The electrophotographic process is a technique for forming a desired image by a series of processes in which a photoreceptor is charged, a latent image is formed by exposure, and developer particles are attached to the latent image to form an image. In the modeling apparatus, particles made of a modeling material are used instead of the developer, but the basic principle of the electrophotographic process is almost the same as that of the 2D printer.

  In FIG. 1A, a photosensitive drum 34 is an image carrier having a photosensitive layer such as an organic photosensitive member or an amorphous silicon photosensitive member. The primary charging roller 33 is a charging device for uniformly charging the photosensitive layer of the photosensitive drum 34. The laser scanner 20 is an exposure device that scans the photosensitive drum 34 with a laser beam and draws a latent image in accordance with an image signal given from the image generation controller 10. The modeling material supply unit 31 is a device that accommodates and supplies the modeling material 35. The developing roller 32 is a developing device that supplies the modeling material 35 to the electrostatic latent image on the photosensitive drum 34. The transfer roller 41 is a transfer device that transfers an image of the modeling material 35 formed on the photosensitive drum 34 to a transfer body (transfer belt) 42. Although not shown, a cleaning device for cleaning the surface of the photosensitive drum 34 may be provided downstream of the transfer nip between the photosensitive drum 34 and the transfer roller 41. In the present embodiment, the photosensitive drum 34, the primary charging roller 33, the modeling material supply unit 31, and the developing roller 32 are integrated as a drum cartridge 30 and configured to be detachable from the modeling apparatus main body, so that replacement is possible. It has become easier. On the other hand, in order to cope with an increase in capacity of the modeling material, a replenishment configuration in which the exposure / development apparatus unit and the material supply unit are separated may be employed.

(Laminated part)
In FIG. 1A, a transfer body 42 is a conveying member that carries the material image 50 formed in the image forming unit and conveys it to the stage 49 (lamination nip). The transfer body 42 is composed of an endless belt member such as resin or polyimide. The heater plate 43 incorporates a heater, melts the material image 50 on the transfer body 42, and is formed on the layered surface 49 a of the stage 49 or the upper surface of the modeled object 51 on the stage 49 (on the layered surface 49 a). It has a heat laminating function for laminating. The stage 49 is a member that holds the modeled object 51 that is being stacked, and can be moved in the vertical direction (stacking direction) by the stage drive motor 48.

(Operation of modeling equipment)
Next, a basic operation for producing a modeled object by the modeling apparatus will be described.
In FIG. 1A, the control unit 60 calculates the cross-sectional shape of each layer by slicing the modeling object at a predetermined pitch (for example, a thickness of several microns to several tens of microns) based on the three-dimensional shape data of the modeling object. Generate slice data for each layer. The image data is input to the image generation controller 10 in order from the lowermost slice data. The image generation controller 10 controls laser emission and scanning of the laser scanner 20 according to the input slice data.

In the image forming unit, the surface of the photosensitive drum 34 is uniformly charged by the primary charging roller 33. When the surface of the photosensitive drum 34 is exposed by the laser beam from the laser scanner 20, the exposed portion is neutralized. The modeling material charged with the developing bias is supplied to the charge removal portion by the developing roller 32, and a material image made of the modeling material is formed on the surface of the photosensitive drum 34. The material image 50 is transferred onto the transfer body 42 by the transfer roller 41.
The transfer body 42 rotates while carrying the material image 50 and conveys the material image 50 to the stacking position. By applying heat by the heater plate 43, the material image 50 is thermally welded to the upper surface of the modeled object 51 on the stage 49. Each time the material image 50 is laminated, the modeling controller 70 lowers the stage 49 by the thickness of one layer in the vertical direction to prepare for the lamination of the next layer.
The modeling object 51 is formed on the stage 49 by repeating the modeling operation including the image forming process for forming the material image 50 and the stacking process for stacking the material images 50 for the number of slice data.

(Explanation of melt lamination of material images)
The process in which the material image 50 is thermally welded and laminated on the upper surface of the modeled object 51 will be schematically described with reference to FIGS.
FIG. 2A shows a state where particles constituting the material image 50 are spread. Generally, the close-packed state on a plane means a hexagonal close-packed state.
FIG. 2B shows a state in which the particles are closely arranged on the modeled object 51 and the heater plate 43 is in contact from the upper surface of the particle via the transfer body 42. The particles shown in FIG. 2B correspond to the AA ′ cross section of FIG. 2A. In the present embodiment, the particle radius is expressed as “r”. Therefore, the diameter is 2r. Actually, “r” is a length having a certain particle size distribution range, and the average value is treated as “r” here.
FIG. 2C shows a state in which the particles start to melt, begin to fill the gaps between the particles, and the position of the shaped object 51 starts to rise. FIG. 2D shows a state where the melting is completed and the gaps between the particles are filled. At this time, since there is no change in the volume of the entire particle, the material image 50 that has been melted has a plate shape as shown in FIG. 2D. The plate thickness of the material image 50 is 1.6r by simple calculation.

(Problems of additive manufacturing)
As in this embodiment, in a modeling apparatus of a type that forms a modeled object by stacking material images, a partial defect in the material image affects the quality of the modeled object. For example, when the development coat cannot be uniformly generated partially in the development process due to a defect in the developing device, streaks or missing coating may occur. Further, when the image of the modeling material 35 is transferred from the photosensitive drum 34 to the transfer body 42, if the transfer bias is not set appropriately or the modeling material 35 is not sufficiently charged, the transfer failure May cause a defect in the material image 50. When a defect occurs in the material image 50, the flatness of the corresponding portion is remarkably lowered at the time of melting, and it becomes difficult to stack and fix the material image 50 of the next layer on the shaped object 51 on the stage 49. Such an image defect can be said to be a problem peculiar to the modeling apparatus.

(Description of material image defect generation)
A process in which a partial defect image is generated in the material image 50 will be schematically described with reference to FIGS.
3A and 3B are schematic diagrams for explaining a case where one particle of the modeling material constituting the material image 50 is defective. FIG. 3A shows a state before melting, and FIG. 3B shows a state after melting. . In FIGS. 3A and 3B, a plan view is shown in the upper part, and a cross-section AA ′ and aa ′ cross-section in the plan view are shown in the lower part. FIG. 3B schematically shows a state in which it is assumed that the upper surfaces of some of the particles around the defect portion are uniformly lowered and the defect portion is filled at the time of melting. At this time, in FIG. 3B, the stacking thickness of the defective portion and a part of the particles around the defective portion is 1.28r in calculation. In this case, there is no change in the total volume of the particles between the state shown in FIG. 3A and the state shown in FIG. 3B. In addition, since the flow of molecules actually occurs, the boundary between the part to which the defect part and a part of the particle around the defect part are added and the part not affected by the defect of the particle around the defect part is illustrated. It does not become vertical as it does, but seems to be inclined gently.

Next, FIG. 3C shows a case where the cross-sectional shape of the boundary 53 shown in FIG. 3B is gently inclined. FIG. 3C shows a state in which, when there is a defect of one particle in the N layer at the lower part, a part of the defect portion and particles around the defect portion flow and incline toward the defect center. In the upper part, when the N + 1 layer as the next layer is in contact with the N layer, and the N + 2 layer as the next layer are stacked almost normally.
If the material is, for example, a complete liquid (for example, milk), the upper surface is uniformly flat throughout the entire layer, but if the material remains solid (for example, processed cheese), the defective portion is maintained as it is. . When the resin melts, because of an intermediate state (for example, yogurt), FIG. 3C schematically illustrates a state where only the vicinity of the defect portion is complemented by being inclined toward the defect portion.
As described above, in the case of a single particle defect, a part of the particles around the defect portion flows, so that the defect portion is naturally repaired and normal lamination can be performed from the third layer.

In the above description, the form in which the defective portion can be normally repaired has been described. However, when the defect range becomes large, the repair may be difficult. This point will be described with reference to FIGS. 3D and 3E.
3D and 3E show schematic arrangements when seven particles are defective. FIG. 3D shows a state before melting, and FIG. 3E shows a state after melting. In FIGS. 3D and 3E, a plan view is shown in the upper part, and an AA ′ section and an aa ′ section in the plan view are shown in the lower part.
When the particles shown in FIG. 3D are melted, the peripheral particles around the defect portion flow toward the center, resulting in the state shown in FIG. 3E. In FIG. 3E, even if the particles are melted, the liquid does not reach a complete liquid state, and even if the material flows, the defect portion is not completely filled, so that an inclined depression is formed. As shown in FIG. 3E, in the Nth layer in which the defect exists, the defect is not completely filled and a portion having no material is generated. Then, by laminating the (N + 1) th layer, the defect portion of the Nth layer is somewhat supplemented, but it is not sufficient, and when the (N + 2) th layer is laminated, the particles of the (N + 2) th layer cannot be brought into close contact with each other. For this reason, it is difficult to continue the lamination.

As described above, an example of the defect that makes it difficult to continue the lamination has been described. In addition to the above example, there are various cases of this phenomenon depending on the viscoelastic characteristics of the modeling material and the melting temperature condition.
Here, we do not mention the number of particles that will be the criterion for determining whether or not it is a defect (the standard for stacking, which will be described later), but verify the shape and number of particles that make it difficult to continue stacking for each modeling material. Just decide. Further, the specification of the sensor resolution may be determined in accordance with the shape and area determination criteria determined for detecting the material image.

Next, a method for detecting the material image of each layer will be described.
First, details of the illumination light source will be described.
(Dark field and bright field)
4A to 4C show a state in which the thin material image 50 is transferred onto the transfer body 42. Since the material image 50 is used for stacking, the stacking thickness is set according to the specifications of the modeling apparatus. Here, for example, the range of the laminated thickness of the material image 50 is set to 10 μm or more for high-precision lamination and 100 μm or less for high-speed lamination. Since the material images 50 of any laminated thickness are in a thin layer state, when the modeling material is a resin, the transmittance becomes high and it becomes difficult to obtain contrast with the transfer body 42.
FIG. 4A shows a state in which normal visible light is irradiated at an angle close to perpendicular to the material surface and reflected light is incident on the sensor. This is called bright field illumination. As shown in the figure, since the reflected light component from the transfer body 42 by transmitted light is large, the contrast between the material image 50 and the transfer body 42 is quite small. When the modeling material is colored in black, the contrast becomes smaller. In order to obtain a good contrast, it is necessary to increase the thickness of the material image 50. However, increasing the thickness of the material image 50 in order to increase the modeling accuracy causes a contradiction.

(Sensing of material images by dark field illumination)
A countermeasure for increasing the contrast with the transfer body 42 against the above problem will be described with reference to FIGS. 4B and 4C.
In the present embodiment, as shown in FIGS. 4B and 4C, the illumination light source is irradiated at a shallow angle with respect to the material surface, so that scattered light is incident on the sensor. This is called dark field illumination. This irradiation angle is desirably 45 degrees or less. This is called the Brewster angle. In general, dark field illumination is used for detecting minute objects in thin layer pieces with a microscope or the like. Also, white is often used as the wavelength of the light source, but a blue light source is more effective in order to improve the scattering characteristics. The wavelength is 470 to 405 nm or the like.
FIG. 4B shows the direction of reflected light when illumination is performed with the surface of the material image 50 being smooth. In the form of FIG. 4B, since the surface of the transfer body 42 is configured to be smooth so that the surface of the material image 50 is smooth, scattered light does not enter the sensor, but at the edge portion of the material image 50, It enters the sensor as scattered light.
On the other hand, FIG. 4C shows the direction of reflected light when illumination is performed with the surface of the material image 50 being a rough surface. In the form of FIG. 4C, the reflected light on the entire surface of the material image 50 becomes scattered light and enters the sensor.
By using this illumination method, it is possible to easily detect a material image composed of the thin layer resin or the dark colored resin used in the present embodiment.

(Illumination optics)
Next, the illumination optical system and sensor arrangement using the dark field illumination will be described.
FIG. 5A is a schematic diagram showing a mode in which the material image 50 is transferred onto the transfer body 42, and the illumination light source 45 irradiates the surface of the material image 50 at an angle of 45 degrees or less with respect to the surface of the material image 50. It is.
The illumination light source 45 is configured such that uniform parallel light irradiation is possible, for example, by passing a cylindrical lens and a diffusion plate through an LED array. And the scattered light when the illumination light source 45 irradiates the surface of the material image 50 is comprised so that it may inject into the line sensor 44a via the lens 44b. In this way, the material image 50 is detected.
The illumination light source 45 and the line sensor 44a can acquire the material image 50 on the transfer body 42 as a two-dimensional image by moving relative to the transfer body 42. In this embodiment, for example, if one particle has a resolution of 600 dpi (dots per inch), the particle diameter “2r” is 42 μm. Therefore, in order to discriminate a single particle defect, a sensor resolution of at least 21 μm is desirable. In the reduction optical system, a CMOS sensor chip having a light receiving portion of 7 μm square can be used if a 21 μm pixel can be captured by a 3 × zoom lens. This is equivalent to a sensor chip equivalent to 1200 dpi and is easily available because it has the same specifications as those used in industrial applications (scanners and copiers).

(1x optical system)
FIG. 5B is a diagram showing a state in which the reduction optical system is replaced with an equal-magnification optical system. Similarly to FIG. 5A, a material image 50 is transferred onto a transfer body 42, and an illumination light source is formed on the surface of the material image 50. 95 is a schematic diagram showing a form in which 95 is irradiated at an angle of 45 degrees or less with respect to the surface of the material image 50. The illumination light source 95 is configured such that uniform parallel light irradiation can be performed, for example, by passing an LED array through a cylindrical lens and a diffusion plate. And it is comprised so that the scattered light when the illumination light source 95 irradiates the surface of the material image 50 injects into the contact | adherence line sensor 91 through the SELFOC (trademark) lens 93. FIG. In this way, the material image 50 is detected. Here, the Selfoc lens 93 is arranged so that the light reflected or scattered on the surface of the material image 50 forms an image on the contact line sensor 91 at an equal magnification. A selfoc lens (selfoc lens array) 93 is an upright or the like that guides light reflected or scattered from the surface of the imaging target (the material image 50 in the present embodiment) to the image sensor (the contact line sensor 91 in the present embodiment). It corresponds to a double optical system.
In the present embodiment, all of these optical systems are integrally formed as the sensor unit 90. Thus, the sensor unit 90 can be reduced in size and weight, and the modeling apparatus 1 can also be reduced in size and weight. Further, by integrating the optical system, optical adjustment becomes unnecessary. Further, the sensor unit 90 can be driven integrally, and it is not necessary to drive the optical system for each member. Note that only the light source may be provided separately, and in this case as well, the same effect as described above can be obtained.

(Difference between reduction optical system and 1x contact optical system)
Next, the difference between the reduction optical system and the equal magnification contact optical system will be described. 6A and 6B are schematic diagrams for explaining the reduction optical system, and FIGS. 6C and 6D are schematic diagrams for explaining the equal magnification contact optical system. 6A and 6B are schematic views of the reduction optical system when viewed from the downstream side in the traveling direction of the transfer body 42. In order to make the optical path easier to see, illumination light sources (45, 45a, 45b) are shown. Shown for convenience. 6C and 6D, the direction in which the transfer body 42 moves relative to the sensor unit 90 is indicated by an arrow.
FIG. 6A shows the configuration of one line sensor and one lens of the reduction optical system. In the reduction optical system, the reduction rate is determined from the relationship between the sensor chip pixel size, the detected image width, and the detection resolution. Therefore, when the detected image width is increased, the reduction rate may be increased, but the detection resolution is lowered. As a countermeasure, in order to increase the detected image width while maintaining the detection resolution, a method of increasing the number of sensor chips or connecting more optical systems can be considered, but it is better to use a general-purpose sensor chip. Since the degree of freedom of design increases, the method of connecting the optical systems shall be selected. FIG. 6B shows a configuration in which an optical system is connected to FIG. 6A. In FIG. 6B, the scattered light when the illumination light sources 45a and 45b irradiate the surface of the material image 50 is configured to enter the line sensors 44a and 44c via the lenses 44b and 44d, respectively. However, in this configuration, the space of the optical system is increased, and optical adjustment between the sensor chips (detection line alignment, sensor output signal end light amount correction, and overlapping pixel connection processing) is required. There is a concern that the design man-hours and adjustment man-hours increase as compared with one sensor chip.

On the other hand, FIG. 6C shows a sensor unit 90 of an equal magnification contact optical system. As shown in FIG. 6C, by using the sensor unit 90 in which the illumination light sources 95 and 96, the contact line sensor 91, and the Selfoc lens 93 are integrated, no optical adjustment is required, and the detection image width can be handled in several lengths. This can be easily achieved by preparing a sensor unit. Further, image processing such as edge light amount correction (shading correction) is unnecessary or can be realized with a simple configuration due to the uniformity of the light amount, which is a merit of the contact sensor. Furthermore, if the advantages of small size and light weight are utilized, the movement on the sensor unit side can be performed when moving relative to the detected image. Thus, the sensor unit 90 moves relative to the transfer body 42, whereby the material image 50 on the transfer body 42 can be acquired as a two-dimensional image.
The configuration of the sensor unit 90 of the equal magnification contact optical system shown in FIG. 6D is different from the configuration of FIG. 6C in the following points. That is, in FIG. 6C, the illumination light sources 95 and 96 are LED arrays, whereas in FIG. 6D, the configuration of the illumination light source is that instead of the illumination light sources 95 and 96, the line light guides 97 and 98 are used for LED one-side illumination. The added configuration is different. That is, in FIG. 6D, the line light guides 97 and 98 are arranged in a line in the orthogonal direction orthogonal to the traveling direction of the transfer body 42 on the surface of the transfer body 42, and the LEDs are arranged from one end side in the orthogonal direction. Irradiation takes place. In the configuration of FIG. 6D, if the required illuminance on the irradiation surface is satisfied, cost reduction and size reduction can be achieved.

(Defect image acquisition and recovery control)
A mechanism for detecting and recovering each defect form of the material image will be described.
FIG. 7 shows the modeling controller 70 described above. The contact line sensor 91, the illumination light source 95, and the cleaner 46 are connected to the IO interface 81 and drive signals are output. Here, the handling of the output signal of the contact line sensor 91 will be described in detail.
FIG. 8 is a configuration block diagram of defect image acquisition and recovery control.
As shown in FIG. 8, the control unit 60 includes a 3D data slicer 61 and a printer driver 62 as functions related to generation of slice data. Shape data such as STL is input to the 3D data slicer 61 as 3D shape data by 3D CAD or the like. In accordance with the input data, slice data for each layer is generated by the 3D data slicer 61. The slice data is output from the printer driver 62 to the image generation controller 10. The control unit 60 and the image control unit 11 are connected with a control signal and image data by an interface signal line.
The image control unit 11 has a storage function, accumulates slice data, and forms a material image by the slice image generation unit 12 based on the slice data according to the stacking timing, and transfers the material image to the stacking unit. The stacking unit includes a laser scanner 20, a drum cartridge 30, a transfer stacking unit 40, and the like. Further, a comparison unit 13 is connected to the image control unit 11 in the image generation controller 10. The comparison unit 13 compares the image acquired by the contact line sensor 91 with the slice data.

(Image comparison algorithm)
FIG. 9 is a schematic diagram for explaining the function of the comparison unit 13.
In FIG. 9, a heart-shaped cosmetic box-like shape is used as a three-dimensional model. In the left grid-like image in FIG. 9, the upper part shows slice data, and the lower part shows material image acquisition data acquired by the contact line sensor 91. In FIG. 9, the comparison result by the comparison unit 13 is shown on the right side. The unitary data of line N among the data is input to the comparison unit 13.
Here, let the acquisition data of the material image typically shown by a black pixel in FIG. 9 be a defective part. The lower line data of the comparison unit 13 indicates the comparison result, and the x part indicates that they do not match. If the comparison result is a mismatch determination, it is determined whether it is a defect or a non-defect. If the stacking cannot be continued, it is determined as a defect. The above is an example performed by comparison of raw data, but if it is a one-dimensional binary comparison, a comparison by run length can be easily performed. Further, the present invention is not limited to line units, and several lines may be combined to perform block unit comparison. Below, an example of a defect detection algorithm is demonstrated according to a flowchart.

(Flowchart 1 of defect image acquisition and recovery processing)
A defect detection algorithm for each layer will be described with reference to the flowchart shown in FIG.
In step 101, slice data is input and stored in the image generation controller 10. In step 102, the slice data is developed into a raster image, and a material image (material image of interest) is formed from the particle image. In step 103, the material image is detected and acquired by the line sensor 44. In step 104, the image acquired by the line sensor 44 is compared with the accumulated slice data. In step 105, it is determined whether the comparison result matches or does not match. If it is determined in step 105 that the values match, the process proceeds to step 106, and the process proceeds to the stacking process.

(Image defect judgment 1)
In step 107, it is determined whether or not the mismatched portion is within the stacking standard. If it is determined in step 107 that the inconsistent portion is within the stackable reference, the process proceeds to step 106 and proceeds to the stacking process. If it is determined in step 107 that the mismatched portion is not within the stackable standard, the process proceeds to step 108 and the corresponding material image is discarded.
Then, it returns to step 102 and modeling is performed by repeating the above process.

As described above, it is possible to acquire the shape of the mismatched part by repeatedly sensing the material image of each layer in units of lines and comparing it with the original slice data, thereby comparing the shape and size with the criterion. By doing so, it can be determined whether there is a defect or not. In the case of the defect determination, the material image of the corresponding layer can be reproduced by discarding the material image (target material image) of the corresponding layer and re-forming the corresponding slice data (target slice data). .
In the present embodiment, the cleaner 46 is disposed as a discarding unit that discards the material image, and the material image on the transfer body 42 is removed by an instruction from the modeling controller 70 when determining the defect. As the cleaner 46, a scraper or an adhesive transfer removing roller for stripping off a material on a flat surface may be used, and selection may be appropriately made according to the characteristics of the transfer body 42 and the modeling material.

In the above description, the material images to be discarded have been described as one layer. On the other hand, when high-speed lamination is performed, the material image of the next layer may be formed when the defect determination of the material image is performed.
In such a case, if the material image of the next layer is different from the material image of the layer determined to be defective, the material image of the next layer must be discarded together with the material image of the layer determined to be defective. There is. Then, it is necessary to re-form the material image corresponding to the material image to be discarded.

  On the other hand, when the material image of the next layer is the same image as the waste material image, only the material image of the layer determined to be defective is discarded, and the formed material image of the next layer is not discarded, and is determined to be a defect. Instead of the material image of the layer, the material image of the next layer may be re-formed and added. Also, for example, if the object to be modeled is a cylinder, only the material image of the layer determined to be defective is discarded, the material image of the next layer that has already been formed is not discarded, and the layer number is subtracted from the discarded material image. It is preferable to continue the stacking by starting from the subsequent layer number. Thereby, the grade which impairs a lamination speed and lamination time can be eased.

(Flowchart 2 of defect image acquisition and recovery processing)
Next, the flowchart 2 will be described with reference to FIG. In the flowchart 1 shown in FIG. 10, the defect detection algorithm in units of layers has been described. In the flowchart 2, the defect detection algorithm in units of lines will be described.
Steps 201 to 205 are almost the same as steps 101 to 105 in the flowchart 1. In step 202, the slice data is developed into a raster image to form a particle image. In step 203, a particle image is detected and acquired by a sensor. In step 206, it is determined whether or not the detection has been completed up to the last line of the material image. If not, the process returns to step 203. When the detection is completed up to the final line, the process proceeds to step 207, where the process proceeds to the stacking process.

(Image defect judgment 2)
In step 205, if there is a mismatch, the process proceeds to step 208. In step 208, the mismatch line data is stored. Thereafter, in step 210, it is determined whether or not the composite image of the mismatched portion of the detection line is within the stackable reference. If the composite image of the mismatched portion of the detection line is within the stackable reference, the process proceeds to step 209, and in the case of negative determination in step 210, the process proceeds to step 211, and after discarding the corresponding material image in step 211, Return to step 202. In step 209, it is determined whether or not the detection has been completed up to the final line of the material image. If it is not the final line, the process returns to step 203. If it is determined that the detection has been completed up to the final line, the process proceeds to the stacking process in step 207.

According to the configuration of the image detection apparatus of the present embodiment described above, an image defect can be detected more reliably, and the image detection apparatus can be reduced in size and weight. Moreover, since an image defect can be detected more reliably, the quality of a molded article can be improved.
Here, in the present embodiment, the image defect when the material image is formed from the slice data has been described, but the present invention is not limited to this. Even when markers that are formed at the leading edge position (including the side edge position and the trailing edge position) of the material image, or markers according to the purpose are formed with the material image, the material image can be detected to achieve each purpose. The present invention can be applied. Depending on the purpose of the marker, the marker is formed at the time of modeling a modeled object by adding the marker data to the slice data generated from the three-dimensional shape data of the modeled object when the model is formed. There is a case. Such a marker may be one in which a marker processing unit included in the control unit 60 performs processing to be formed by the image forming unit, transferred to the transfer body 42, and conveyed.
In addition, as described above, the material image is formed by combining one or a plurality of material images according to the type of modeling material to be used. That is, even when the modeling apparatus performs modeling using a plurality of modeling materials, the present invention can be suitably applied.
In the present embodiment, the image acquisition unit includes a dark field illumination that irradiates the transfer body with light and an image sensor that captures the scattered light of the light from the modeling material on the transfer body. Thus, even if the material image of each layer is a thin layer and has high transmittance or low contrast, the shape of the material image or particle image can be recognized. For this reason, this invention can be applied to the whole apparatus which models a layered material image, and can be utilized for many uses besides the defect detection of a material image. For example, the present invention can be used also when detecting a residue such as a modeling material remaining on the transfer body 42 or when detecting a cleaning failure after cleaning the transfer body 42.
Further, in the present embodiment, the material image 50 transferred to the transfer body 42 and conveyed in the modeling apparatus 1 is described as corresponding to the imaging target object, but is not limited thereto. If the imaging object is a material image made of a particulate material supported on a carrier, the present invention can be suitably applied, and image defects in the material image can be detected more reliably. it can.

Second Embodiment
(Configuration of modeling equipment)
The configuration of the sensor unit according to the second embodiment will be described with reference to FIG. FIG. 12 is a schematic diagram showing a sensor unit according to the present embodiment. In the present embodiment, configurations and processes different from those in the first embodiment will be described, and descriptions of configurations and processes similar to those in the first embodiment will be omitted.
In the sensor unit shown in FIGS. 6C and 6D in the first embodiment, the illumination light source irradiates the irradiated portion on the surface of the material image 50 on the transfer body 42 from both upstream and downstream sides in the traveling direction of the transfer body 42. It was the composition to do.
On the other hand, in this embodiment, as shown in FIG. 12, the sensor unit 90a that the illumination light source 95 irradiates the irradiated portion from the downstream in the traveling direction of the transfer body 42, and the illumination light source 96 that irradiates from the upstream. And a sensor unit 90b. Here, FIG. 12 shows a cross section of a defective portion of the material image 50, and the defective portion is formed to be inclined with respect to the traveling direction of the transfer body 42 (inclined with respect to the optical path passing through the SELFOC lens 93). An example of a fine defect is shown.

In defect detection, it is common to select double-sided irradiation as shown in FIGS. 6C and 6D for the purpose of performing image defect detection independent of the inclined shape of the defect portion. However, even when a double-sided irradiation optical system is used, if the fine defect is inclined as shown in FIG.
In the present embodiment, a plurality of sensor units are provided, and the illumination angles of the illumination light sources are different from each other. That is, a plurality of illumination light sources having different irradiation angles are arranged, and light reflected or scattered by the irradiated portion by irradiation of each illumination light source is detected by each line sensor arranged corresponding to each illumination light source. Thereby, even if the fine defect is inclined as described above, detection by any of the line sensors becomes possible.
FIG. 12 shows how the sensor unit 90a and the sensor unit 90b detect images by moving relative to the material image 50 at a certain distance from each other. In this case, the logical sum of the mismatched portions of the two line data may be input to the comparison unit 13 in FIG.

As shown in FIG. 6C, a method is conceivable in which the illumination light source 95 and the illumination light source 96 are arranged in the same sensor unit 90 so that the irradiation directions are different from each other, and the lighting timing is exclusively time-divisionally. However, such a method is simple at low speed and can be reduced in cost, but is not suitable for the purpose of detecting an image defect at the same position at the same time at high speed.
In the reduction optical system shown in FIGS. 6A and 6B, when a plurality of illumination light sources are provided so that the irradiation directions are different from each other, and a lens and a line sensor corresponding to each illumination light source are provided, a wider installation space is provided. There is a concern that it will be difficult to secure the installation space.

  Also in this embodiment, an image defect can be detected more reliably, and the image detection apparatus can be reduced in size and weight. Moreover, since an image defect can be detected more reliably, the quality of a molded article can be improved.

90 ... sensor unit, 91 ... contact line sensor, 93 ... selfoc lens, 95 ... illumination light source

Claims (7)

Linear illumination that irradiates light at an angle of 45 degrees or less with respect to the surface of the imaging object;
A line-shaped image sensor arranged in parallel with the line-shaped illumination;
An erecting equal-magnification optical system that guides light reflected or scattered by the surface of the imaging object to the image sensor;
An image detection apparatus comprising: The erecting equal-magnification optical system has a selfoc lens array, and is arranged so that light reflected or scattered by the surface of the imaging object forms an image at the same magnification on the image sensor. The image detection apparatus according to claim 1. The image detection apparatus according to claim 1, wherein the imaging object is a material image made of a particulate material carried on a carrier. 2. The illumination object, the image sensor, and the erecting equal-magnification optical system detect the imaging object as a two-dimensional image by moving relative to the imaging object. 4. The image detection device according to any one of items 3. A modeling apparatus for producing a three-dimensional object by laminating material images made of modeling materials based on three-dimensional shape data of a three-dimensional model,
An image forming unit that forms the material image based on slice data generated from the three-dimensional shape data;
The image detection apparatus according to any one of claims 1 to 4, which detects the material image;
A modeling apparatus comprising: Comparison means for comparing the data detected by the image sensor with the slice data;
A determination unit that determines whether the material image is a material image that can be stacked based on a comparison result by the comparison unit;
The modeling apparatus according to claim 5, comprising: A plurality of the image detection devices;
The modeling apparatus according to claim 5, wherein the plurality of image detection devices are arranged so that irradiation angles of the respective illuminations with respect to the surface of the material image are different from each other.

Images