JP6288218B2 - Edge position detection device, conveyance device, image forming apparatus, and edge position detection method - Google Patents

Description

The present invention relates to an edge position detection device, a conveyance device, an image forming apparatus, and an edge position detection method .

  Conventionally, in an image reading apparatus such as a scanner or an image forming apparatus such as a printer, it is important to accurately convey a sheet or the like as a medium to be read or written. For this reason, at the time of factory shipment or the like, the end (edge) of the paper is detected, and it is inspected whether or not the deviation between the preset transport position and the actual transport position is within an allowable range. In the inspection of the paper transport position, the paper transported at the inspection position is irradiated with white light and imaged with a camera, and the captured image is binarized to detect the edge of the paper.

  However, in the above-described prior art, it may be difficult to detect an edge from a binarized image when the paper color and the background color are the same color, and the detection accuracy may be reduced. Further, when the paper conveyance speed is high, it is necessary to shorten the exposure time of the camera, and a white light source that irradiates stronger light is required, so that it is difficult to easily inspect.

The present invention aims to provide at least partially solve the problems in the high Mel edge position detecting device, the detection accuracy of the transport position of the mobile, conveying device, an image forming apparatus and the edge position detection method To do.

In order to solve the above-described problems and achieve the object, an edge position detection device according to the present invention includes an irradiation unit that irradiates light to an area including an edge of a moving body, and speckles that appear in the area irradiated with the light. imaging means for capturing an image at a predetermined time interval, based on two speckle images captured in the predetermined time interval, the movement amount of the Utsushitai that put the plurality of locations within said speckle image Calculating means for calculating, and detecting means for detecting an edge position of the moving body in the region irradiated with the light based on the movement amount of the subject calculated at the plurality of positions, the detecting means comprising: The edge position is detected based on the movement amount of the subject detected at the plurality of positions and a predetermined threshold value .

The edge position detection method according to the present invention includes an irradiation step of irradiating light to an area including an edge of a moving body, and an imaging step of capturing speckle images appearing in the light irradiation region at a predetermined time interval. , on the basis of the predetermined time the two speckle images captured at intervals, a calculation step of calculating a movement amount of the Utsushitai that put the plurality of locations within said speckle image, calculated by the plurality of locations based on the movement amount of the object that is, seen including a detection step, a detecting an edge position of the movable body in the area of radiating the light, the detection step, the subject detected at said plurality of locations The edge position is detected based on the amount of movement and a predetermined threshold value .

According to the present invention, an effect the detection accuracy of the transport position of the mobile high-Mel, called.

FIG. 1 is a conceptual diagram exemplifying a case where a sheet conveyance inspection in an automatic document conveying apparatus is performed using the inspection apparatus according to the present embodiment. FIG. 2 is a block diagram illustrating the configuration of the inspection apparatus according to this embodiment. FIG. 3 is a conceptual diagram illustrating a captured image captured by the inspection apparatus. FIG. 4 is a conceptual diagram illustrating movement amount calculation based on the image correlation between two speckle images. FIG. 5 is a conceptual diagram illustrating the calculation of the movement amount for each image area and the edge detection of the paper. FIG. 6 is a block diagram illustrating the configuration of an inspection apparatus according to a modification. FIG. 7 is a conceptual diagram illustrating a mark image printed on the surface of a sheet.

  Hereinafter, an embodiment of an inspection apparatus and an inspection method will be described in detail with reference to the accompanying drawings. In the following embodiments, an inspection apparatus and an inspection method for inspecting a paper transport position at a reading position of an automatic document feeder (ADF) will be described as an example.

  However, the moving object to be inspected and the inspection position of the moving object are not particularly limited. For example, an intermediate transfer belt in an image forming apparatus that forms a color image on a sheet by a tandem method may be used as a moving object to be inspected. Also, the inspection position of the moving body may be other than the reading position, such as a paper feeding position or an image forming position when image formation is performed.

  FIG. 1 is a conceptual diagram exemplifying a case where a paper conveyance inspection in the automatic document conveyance device 120 is performed using the inspection device 1 according to the present embodiment. In FIG. 1, the mechanical structure of the paper feed conveyance mechanism of the automatic document conveyance device 120 is illustrated in cross section.

  As shown in FIG. 1, in the automatic document feeder 120, a plurality of sheets stacked on a paper feed tray 121 are fed by a pickup roller 122 at the start of reading and conveyed via a conveyance roller 123. The paper is discharged onto a paper discharge tray 127 by a paper discharge roller 126. In this conveyance process, the sheet is read through the ADF original glass 125 when it reaches the reading position of the background plate 124. Therefore, in the automatic document feeder 120, it is important in terms of reading accuracy that the paper conveyance speed at the reading position is a predesigned speed.

  For this reason, the inspection apparatus 1 reads (captures) the reflected light 3 by the irradiation light 2 at the reading position of the automatic document conveying apparatus 120, and determines the edge position of a sheet of a predetermined shape (for example, A4 size) to be conveyed. To detect. Then, the inspection apparatus 1 determines whether the detected edge position is a preset position (for example, an edge position corresponding to A4 size paper), thereby checking the quality of the paper transport position.

  FIG. 2 is a block diagram illustrating the configuration of the inspection apparatus 1. As shown in FIG. 2, the inspection apparatus 1 includes a laser light source 11, a camera 12, a camera image memory 13, an image reading unit 14, a movement amount calculation unit 15, a movement amount storage unit 16, and an edge detection unit. 17 and an output unit 18.

  Specifically, the laser light source 11, the camera 12, and the camera image memory 13 of the inspection apparatus 1 irradiate the surface of the paper P with the irradiation light 2 that is laser light, and image the reflected light 3 from the paper P. It may be an optical system device. In addition, the image reading unit 14, the movement amount calculation unit 15, the movement amount storage unit 16, the edge detection unit 17, and the output unit 18 of the inspection apparatus 1 are images captured by the camera 12 and a CPU (Central Processing Unit) is a RAM. It may be an information processing device such as a PC (Personal Computer) that performs processing by executing a program expanded in (Random Access Memory).

  The laser light source 11 has an area for detecting the edge of the paper P at the reading position of the automatic document feeder 120 (for example, a diameter of about 4 to 5 mm centered on a design position that is an edge position of the A4 size paper P). A range) is irradiated with irradiation light 2 which is laser light. The camera 12 captures the reflected light 3 of the speckle image appearing on the subject in the region irradiated with the irradiation light 2, that is, the paper P and the background plate 124, at a predetermined time interval (frame rate).

  FIG. 3 is a conceptual diagram illustrating a captured image G captured by the inspection apparatus 1. As shown in FIG. 3, the captured image G is an area irradiated with coherent light such as laser light, and a spec that is a bright and dark spot pattern generated in scattered light (reflected light 3) due to the uneven structure on the subject surface in the area Image G1, G2.

  In the captured image G, the speckle image G1 of the portion where the paper P to be transported is displaced by the amount of movement of the paper P that moves at the frame rate interval. Further, the speckle image G2 corresponding to the background plate 124 without the sheet P to be conveyed is stationary. Therefore, the inspection apparatus 1 can detect that the edge position of the paper P is conveyed in the vicinity of the designed position by detecting the speckle image G1 and the speckle image G2 of the captured image G.

  The camera image memory 13 sequentially stores (stacks) captured images G captured by the camera 12 at a predetermined frame rate. The image reading unit 14 sequentially reads the captured images G (speckle images G 1 and G 2) sequentially stored in the camera image memory 13 and outputs them to the movement amount calculation unit 15. Specifically, the t-th captured image is read (141) and the t + 1-th captured image that is the next frame image is read (142) and output to the movement amount calculation unit 15.

  The movement amount calculation unit 15 calculates the movement amount of the subject (paper P, background plate 124) at the frame rate interval for each position of the captured image based on the image correlation of the t-th captured image and the t + 1-th captured image. To do. The movement amount storage unit 16 stores the movement amount for each position of the captured image calculated by the movement amount calculation unit 15.

  FIG. 4 is a conceptual diagram illustrating movement amount calculation based on image correlation between two speckle images (t-th captured image, t + 1-th captured image). As illustrated in FIG. 4, the movement amount calculation unit 15 performs correlation calculation (for example, phase-only correlation) between two speckle images to obtain a correlation peak, and a movement amount (vector) of a subject corresponding to the correlation peak. Amount).

  Note that the movement amount calculation unit 15 performs the correlation calculation of the two speckle images for each image area divided by a predetermined width, and calculates the movement amount of the subject for each position corresponding to the image area.

  FIG. 5 is a conceptual diagram illustrating the calculation of the movement amount for each image area and the edge detection of the paper. As illustrated in FIG. 5, the movement amount calculation unit 15 includes image regions R1 to Rn arranged in a direction orthogonal to the transport direction with a height of gh and a width of gw, and two speckle images. By calculating the correlation, the movement amount of the subject at the position corresponding to the image regions R1 to Rn is calculated. Note that the sections of the image areas R1 to Rn may be changed as appropriate according to the calculation capability and the required position accuracy.

  The edge detection unit 17 reads the movement amount of the subject calculated for each position corresponding to the image regions R1 to Rn in the speckle image from the movement amount storage unit 16, and the edge of the paper P in the region irradiated with the laser light Detect position. Specifically, the edge detection unit 17 linearly interpolates the movement amount discretely calculated for each position corresponding to the image regions R1 to Rn in a direction orthogonal to the transport direction, and reads a ROM (Read Only Memory) or the like. Is compared with a preset threshold th.

  Here, for a portion where the paper P is present, a movement amount corresponding to the transport speed is detected. Further, since the portion where there is no paper P is stationary, the movement amount is a small value. Therefore, the edge detection unit 17 detects the boundary below the threshold th as the edge position (end position) of the paper P. Note that the edge position of the paper P may be detected as an offset amount with respect to a predetermined position of the captured image G.

  Based on the edge position of the paper P detected by the edge detection unit 17, the output unit 18 outputs the quality of the transport position of the paper P to the user by display display or voice output. For example, when the detected edge position (offset amount) of the paper P is within a predetermined range (about 1 mm), the output unit 18 outputs that the inspection result of the transport position of the paper P is good. . Further, when the detected edge position (offset amount) of the paper P exceeds a predetermined range (about 1 mm), the inspection result of the transport position of the paper P is output as being defective.

  As described above, the inspection apparatus 1 applies the laser light source 11 that irradiates the laser light to the region for detecting the edge of the sheet P to be inspected, and the speckle image that appears on the subject in the region irradiated with the laser light for a predetermined time. A camera 12 that captures images at intervals, and a movement amount calculation unit 15 that calculates a movement amount of a subject for each position in the speckle image based on the image correlation between two speckle images captured at a predetermined time interval; Based on the movement amount of the subject calculated for each position in the speckle image, the edge detection unit 17 that detects the edge position of the paper P in the region irradiated with the laser light, and the paper based on the detected edge position And an output unit 18 that outputs the quality of the P transport position.

  Therefore, since the inspection apparatus 1 detects the edge position of the paper P based on the image correlation between two speckle images captured at a predetermined time interval, the color of the paper P and the color of the background plate 124 are the same. Even in the case of color, the edge of the paper P can be accurately performed. Further, since the inspection apparatus 1 uses the laser light source 11 having a higher brightness than the white light source, the exposure time in the camera 12 can be shortened, and it can easily cope with the case where the conveyance speed of the paper P is high.

(Modification)
A modification of the above-described embodiment will be described. In addition, about the same structure as embodiment mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted. FIG. 6 is a block diagram illustrating the configuration of an inspection apparatus 1a according to a modification.

  As shown in FIG. 6, the inspection apparatus 1 a further includes a light source 19 such as a white light source and a resist detection unit 20. The camera 12 captures not only the area for detecting the edge of the paper P but also the surface (entire or part) of the paper P. That is, the camera 12 images the surface of the paper P including the speckle image by the irradiation light 2.

  The camera 12 may be captured by the same camera, or a camera that captures a speckle image by the irradiation light 2 and a camera that captures the surface of the paper P may be separated. However, in the case of imaging with the same camera, a frame that is captured with an exposure time that matches the brightness of the paper P by the light source 19 and a frame that is captured with an exposure time that matches the speckle image by the irradiation light 2 are alternately captured. It is assumed that the surface of the paper P and the speckle image are alternately captured at predetermined time intervals.

  The registration detection unit 20 detects the position of the end of the paper P with respect to the reference position (dotted line in FIG. 7) from the captured image of the surface of the paper P, and outputs the detection result to the output unit 18. Specifically, the registration detection unit 20 reads the captured image G from the camera image memory 13 and binarizes it, thereby recognizing the edge of the paper P in the captured image G, and the recognized edge of the paper P and the reference The distance in the direction orthogonal to the conveyance direction with respect to the position to be is detected. The reference position may be a position set in advance in a memory or the like as a predetermined position based on a pixel position or the like in the captured image.

  Based on the relative position between the edge position of the paper P detected by the edge detection unit 17 and the reference position detected by the registration detection unit 20, the output unit 18 displays whether the conveyance position of the paper P is good or bad. And output to the user by voice output.

  FIG. 7 is a conceptual diagram illustrating the edge of the paper P and the reference position. As shown in FIG. 7, it is assumed that a distance M in a direction orthogonal to the transport direction between the edge of the sheet P at the time of inspection and a reference line (dotted line) is detected.

  The output unit 18 detects the distance X described above, and determines whether the detected value is a preset value, thereby outputting pass / fail of the transport position of the paper P. For example, the skew during conveyance of the paper P may be detected by detecting the distance X and the edge position in the upper end portion, the intermediate portion, and the lower end portion. As described above, the inspection apparatus 1a detects the edge of the paper P from the speckle image, and conveys the edge of the paper P, the reference position, and the relative position based on the image obtained by imaging the surface of the paper P. An inspection may be performed.

  In the above-described embodiment and the modification, the example in which the present invention is applied to the sheet conveyance inspection apparatus has been described. However, the present invention is not limited to the sheet conveyance inspection apparatus, but can be applied to any inspection apparatus that performs conveyance inspection of a moving body. In contrast, it can be widely applied. The technical matters disclosed as the above-described embodiments and modifications are examples of preferable applications of the present invention, and the technical scope of the present invention is limited to the technical matters disclosed as the above-described embodiments and modifications. It is not a thing. The technical scope of the present invention includes various modifications and alternative techniques that can be easily conceived within the scope of the present invention, in addition to the specific technical matters disclosed as the above-described embodiments and modifications.

  DESCRIPTION OF SYMBOLS 1, 1a ... Inspection apparatus, 2 ... Irradiation light, 3 ... Reflected light, 11 ... Laser light source, 12 ... Camera, 13 ... Camera image memory, 14 ... Image reading part, 15 ... Movement amount calculation part, 16 ... Movement amount memory | storage , 17 ... Edge detection unit, 18 ... Output unit, 19 ... Light source, 20 ... Registration detection unit, 21 ... Output unit, 120 ... Automatic document feeder, 124 ... Background plate, G ... Captured image, G1, G2 ... Specifications Image, M ... mark image, P ... paper, R1-Rn ... image area, th ... threshold.

JP 2002-236828 A

Claims (11)

Irradiating means for irradiating light to the region including the edge of the moving body;
Imaging means for imaging speckle images appearing in the light-irradiated region at predetermined time intervals;
A calculation unit based on two speckle images captured at the predetermined time intervals, calculates the movement amount of the Utsushitai that put the plurality of locations within said speckle image,
Detecting means for detecting an edge position of the moving body in the region irradiated with the light based on the movement amount of the subject calculated at the plurality of positions;
Equipped with a,
The detecting means detects an edge position based on a movement amount of the subject detected at the plurality of positions and a predetermined threshold;
An edge position detection apparatus characterized by the above. The calculation means performs a correlation operation for each of a plurality of image regions in the speckle image with respect to the two speckle images, and calculates a movement amount of the subject at the plurality of positions.
The edge position detection apparatus according to claim 1, wherein The irradiation means irradiates light to an area including an edge and a background plate of the moving body,
The edge position detection apparatus according to claim 1 or 2 , wherein The moving body is paper;
The edge position detection apparatus according to any one of claims 1 to 3 , wherein The imaging means images the surface of the paper including the speckle image;
Edge position detecting device according to any one of claims 1 to 4, characterized in that. The imaging means comprises a plurality of cameras.
The edge position detection apparatus according to claim 5 , wherein: Conveying means for conveying the moving body;
Irradiating means for irradiating light to an area including an edge of the moving body;
Imaging means for imaging speckle images appearing in the light-irradiated region at predetermined time intervals;
A calculation unit based on two speckle images captured at the predetermined time intervals, calculates the movement amount of the Utsushitai that put the plurality of locations within said speckle image,
Detecting means for detecting an edge position of the moving body in the region irradiated with the light based on the movement amount of the subject calculated at the plurality of positions;
Equipped with a,
The detecting means detects an edge position based on a movement amount of the subject detected at the plurality of positions and a predetermined threshold;
A conveying apparatus characterized by that. A second detection means for detecting a distance between an edge position for transporting the mobile body and a reference position in a direction orthogonal to the transport direction of the mobile body;
The conveying apparatus according to claim 7 . Conveying means for conveying the moving body;
Image forming means for forming an image on the moving body;
Irradiating means for irradiating light to an area including an edge of the moving body;
Imaging means for imaging speckle images appearing in the light-irradiated region at predetermined time intervals;
A calculation unit based on two speckle images captured at the predetermined time intervals, calculates the movement amount of the Utsushitai that put the plurality of locations within said speckle image,
Detecting means for detecting an edge position of the moving body in the region irradiated with the light based on the movement amount of the subject calculated at the plurality of positions;
Equipped with a,
The detecting means detects an edge position based on a movement amount of the subject detected at the plurality of positions and a predetermined threshold;
An image forming apparatus. The detecting means detects a position of the moving body when the image forming means performs image formation;
The image forming apparatus according to claim 9 . An irradiation step of irradiating the region including the edge of the moving body with light;
An imaging step of imaging speckle images appearing in the light-irradiated region at predetermined time intervals;
A calculation step of, based on two speckle images captured at the predetermined time intervals, calculates the movement amount of the Utsushitai that put the plurality of locations within said speckle image,
A detection step of detecting an edge position of the moving body in the region irradiated with the light based on the movement amount of the subject calculated at the plurality of positions;
Only including,
The detecting step detects an edge position based on a movement amount of the subject detected at the plurality of positions and a predetermined threshold;
An edge position detection method characterized by the above.