JP2005214734A - Device for inspecting paper wrinkle, and control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect wrinkles in papers formed in a image forming processing. <P>SOLUTION: Wrinkles 20, extending in the direction vertical to the roll axes of fixing rolls 12 and 14, tend to form in paper 16. Then, two imaging parts 38 and 44 arranged in the roll axial direction are provided to image the same place, on the basis of the light emitted from an illumination part 32. By this method, two image data, different in luminance or the like in the vicinity of the wrinkles 20 of the paper caused by the difference between imaging angles, are obtained. An inspection image data forming part 46 forms two inspection image data on the paper 16, on the basis of the subsequently obtained image data. Further, an edge data forming part 52 forms edge data, formed by extracting a linear element from each of the inspection image data. A difference data forming part 52 forms difference data from two edge data. The wrinkles of the paper 20 are detected, by comparing the edge recorded on the difference data with the reference value by a detection part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for inspecting a paper sheet formed on a sheet.

  For example, in an image forming apparatus, there is a case where a paper sheet is bent in the process of forming a print image on the paper.

  Japanese Patent Application Laid-Open Publication No. 2004-228561 discloses a technique for detecting a change in stress caused by a paper sheet in a fixing roller that pressurizes the sheet and inspecting the paper sheet.

Japanese Patent Laid-Open No. 9-296997

  In the technique of the above-mentioned Patent Document 1, the detection accuracy of the paper sheet is determined by the detection resolution of the stress change. In general, it is difficult to detect a change in stress with a fine resolution, and it is not always possible to inspect a paper sheet with sufficient accuracy.

  An object of the present invention is to improve the inspection accuracy of paper sheets.

  Another object of the present invention is to inspect a paper sheet based on inspection image data generated by imaging a sheet.

  The paper sheet inspection apparatus according to the present invention includes an illuminating unit that irradiates a sheet with light, an imaging unit that reads the corresponding reflected light to image the sheet, the illuminating unit, and the imaging unit. In contrast, inspection image data generating means for generating a plurality of inspection image data picked up at different irradiation angles or reflection angles from each other, and the plurality of inspection image data are compared to detect a paper sheet formed on the paper And detecting means for performing.

  The illumination means irradiates the sheet with inspection light. Then, the imaging unit images the paper by reading the reflected light of the irradiated light. The inspection image data generation unit generates a plurality of inspection image data by using the illumination unit and the imaging unit. In the generation of the inspection image data, at least one of the light angle condition, that is, the irradiation angle with respect to the paper (that is, the incident angle with respect to the paper) and the reflection angle with respect to the paper is different.

  A paper basket refers to a three-dimensional shape formed by bending a paper sheet. Each inspection image data imaged and formed using light of different irradiation angles or reflection angles is recorded in the state where the shadow, reflection luminance, paper sheet shape, and the like are different in the vicinity of the paper sheet. The detecting means compares the respective inspection image data and finds this difference, thereby detecting a paper sheet.

  According to this apparatus configuration, it is possible to detect a paper bottle generated on a sheet with high accuracy based on analysis of inspection image data. The generated inspection image data can be reused for other inspections on the paper.

  Preferably, in the paper sheet inspection apparatus of the present invention, the paper is a paper that has undergone an image forming process including a pressurizing process with a rotating fixing roll, and the irradiation angle or the reflection angle is at least that of the fixing roll. The angles in the roll axis direction are different from each other with respect to the paper. The image forming process is a process for forming a print image on paper such as paper based on image data. Many image forming processing systems employ a process in which toner or ink attached to a sheet is pressed by a fixing roll. For this reason, paper jam occurs on the paper that is distorted and sent to the fixing roll. In particular, the paper sheet tends to extend linearly in the paper feeding direction (that is, the direction perpendicular to the roll axis of the fixing roll). Therefore, when a plurality of inspection image data in which the angle condition of the light is changed in the roll axis direction of the fixing roll is generated, the linear paper sheet can be easily detected.

  Preferably, in the paper sheet inspection apparatus according to the present invention, the irradiation angle or the reflection angle is equal to each other in an angle perpendicular to a roll axis of the fixing roll. It is necessary to change the angle condition in order to detect paper jam. However, if the angle condition is greatly different, comparison may be difficult because the shape distortion between the generated inspection image data is conspicuous. Therefore, in some cases, the angle conditions may be equal for the direction perpendicular to the roll axis of the fixing roll.

  Preferably, in the paper sheet inspection apparatus according to the present invention, the inspection image data generation means includes inspection image data based on imaging of reflected light reflected at an equal angle and inspection image based on imaging of reflected light reflected at an unequal angle. Generate data and. The equi-angle refers to a state in which the irradiation angle is equal to the reflection angle, that is, the reflection angle is the main reflection direction. Inspection image data formed by imaging at an equal angle can be used for performing a gloss inspection of a sheet, that is, an inspection relating to the reflectance in the main reflection direction. In addition, inspection image data formed by imaging at non-equal angles can be used for quality inspection of a printed image formed on a sheet, that is, inspection of density, color unevenness, or dirt. Thus, by inspecting the paper sheet based on these at least two inspection image data, it is possible to effectively use the acquired inspection image data and simplify the apparatus configuration.

  Preferably, in the paper sheet inspection apparatus according to the present invention, the imaging unit has a function of performing imaging from a plurality of different angles with respect to the paper, and the inspection image data generation unit is configured to have the plurality of different angles. The plurality of inspection image data is generated on the basis of the imaging result. That is, the plurality of inspection image data is generated based on imaging from different angles with respect to the sheet. For this reason, the imaging unit may include a plurality of parts related to imaging, or may include a mechanism for moving the part related to imaging. Further, the imaging unit may perform a plurality of imaging at different times, or may perform the imaging at the same time (when there are parts related to a plurality of imaging).

  Preferably, in the paper sheet inspection apparatus according to the present invention, the illumination unit has a function of illuminating the paper from a plurality of different angles, and the inspection image data generation unit is configured from the plurality of different angles. The plurality of inspection image data is generated based on the imaging result corresponding to the illumination. That is, a plurality of inspection image data is generated based on imaging using irradiation light having different irradiation angles with respect to the paper. For this reason, the illuminating means may include a plurality of portions related to irradiation, or may include a mechanism for moving the portion related to irradiation. The illumination unit performs a plurality of irradiations at different times, and the imaging unit performs imaging based on the irradiations.

  Preferably, in the paper sheet inspection apparatus according to the present invention, the illumination unit includes a plurality of irradiation ports arranged in an array facing the paper, and the plurality of irradiation ports are classified into at least two groups. Illumination is performed by lighting in different periods, and the inspection image data generation means generates the plurality of inspection image data based on the imaging result of reflected light corresponding to the lighting of the irradiation ports of each group. That is, the illumination means includes a plurality of irradiation ports arranged in a one-dimensional or two-dimensional array, and emits light from the irradiation ports. The plurality of illumination openings do not necessarily have to face the paper, and may face each other with an inclination. The plurality of irradiation ports are divided into at least two groups, and light with different irradiation angles can be irradiated by performing irradiation at different timings between the groups.

  Preferably, in the paper sheet inspection apparatus according to the present invention, the group includes three groups formed by selecting a plurality of irradiation ports at regular intervals when viewed in one direction. The regular interval may be a regular interval in terms of distance, but particularly preferably refers to a regular number interval of irradiation ports. This is because the interval between the irradiation ports is often dense in the periphery of the reading area in order to correct the peripheral dimming with respect to the imaging system. The formation of three groups is formed by selecting, for example, every other two in the arrangement direction when the irradiation ports are arranged in a one-dimensional array. In addition, when the irradiation ports are arranged in a two-dimensional array, three groups are formed by selecting, for example, every two in a certain direction in the plane. By forming three pieces of inspection image data using light irradiated at three different irradiation angles, it is possible to detect paper sheets that are overlooked by two, and the detection accuracy is improved.

  Preferably, the paper sheet inspection apparatus of the present invention includes a type processing unit that acquires the type of the paper type and does not detect the paper sheet for a type of paper having an uneven surface. For example, in the case of a sheet with an uneven surface such as an embossed sheet, the paper sheet detection resolution decreases. Therefore, it is preferable not to perform at least detection means for such a sheet, and it is particularly preferable not to generate inspection image data.

  Preferably, the paper sheet inspection apparatus according to the present invention further comprises setting means for setting a reference for paper sheet detection in the detection means. The size of the generated paper basket may vary depending on the roughness (degree of unevenness), thickness, size, etc. of the paper surface. Thus, by changing the detection criteria automatically or by user settings, false detection can be reduced and detection accuracy can be improved. In the case of performing automatically, for example, information on the paper type is acquired, and a detection reference is set to a threshold value corresponding to the type.

  Preferably, in the paper sheet inspection apparatus according to the present invention, the detection unit extracts edge data from a plurality of inspection image data, compares the extracted edge data, and detects paper sheets formed on the paper. Do. Paper bags are often formed in a line. Therefore, edge data including linear elements is extracted from the inspection image data by a filter, and the extracted edge data are compared. The edge data may be obtained by, for example, line image extraction by Hough transform or the like, but it is particularly desirable to perform edge extraction processing based on a method such as a difference between adjacent pixels in consideration of speeding up of processing. Further, it is particularly desirable that the edge data is generated as binary data based on an appropriate threshold value, thereby enabling further high-speed processing. In comparison, it is necessary to match the positions of the two edge data with an accuracy higher than the detection accuracy. This is performed, for example, by providing an optical lens for reducing image distortion in the imaging means, correcting image distortion by data conversion, or associating a specific part such as the outer side of the paper. be able to. In the paper sheet inspection apparatus of the present invention, the detection unit generates difference data of each inspection image data, extracts edge data from the generated difference data, and detects paper sheets formed on the paper. You may go. As described above, the generation order of the difference data and the extraction of the edge data can be appropriately changed in order of execution.

  A paper sheet inspection program according to the present invention is a program executed in a paper sheet inspection system including an illuminating unit that irradiates light on a sheet and an imaging unit that reads the corresponding reflected light and images the sheet. And a plurality of inspection image data generating procedures for generating a plurality of inspection image data imaged at different irradiation angles or reflection angles with respect to the paper using the illumination unit and the imaging unit; And a detection procedure for detecting a paper sheet formed on the paper. The paper sheet inspection system may consist of one housing or another housing.

  The paper sheet inspection method of the present invention is a method executed by a paper sheet inspection system including an illuminating unit that irradiates light on a sheet and an imaging unit that reads the corresponding reflected light and images the sheet. An inspection image data generation step of generating a plurality of inspection image data captured at different irradiation angles or reflection angles with respect to the paper using the illumination unit and the imaging unit; and A detection step of performing a comparison and detecting a paper web formed on the paper.

  The control apparatus of the present invention is an apparatus that controls a paper sheet inspection system including an illuminating unit that irradiates light to a sheet, and an imaging unit that reads the corresponding reflected light and images the sheet. A means for generating a plurality of inspection image data imaged at different irradiation angles or reflection angles with respect to the paper by using an illuminating means and the imaging means, and formed on the paper by comparing the plurality of inspection image data. And a means for detecting the detected paper sheet. The control device may be incorporated in the paper sheet inspection system or may be provided in a separate housing. In the case of a separate casing, the control operation may be performed via a network.

  Hereinafter, typical embodiments of the present invention will be described.

  FIG. 1 is a diagram showing an outline of a device configuration according to the present embodiment. These configurations are part of the image forming system 10. The image forming system 10 is an apparatus that forms a print image on paper such as a copier or a printer. The image forming method is not particularly limited, and may be, for example, an electrophotographic method, an inkjet method, or an offset method. The electrophotographic image forming system 10 is provided with a fixing roll group including an upper fixing roll 12 and a lower fixing roll 14. These fixing roll groups are provided with a roll shaft serving as a rotation axis in the y-axis direction of FIG. Then, the upper fixing roll 12 rotates counterclockwise in the figure, and the lower fixing roll 14 rotates clockwise in the figure to pressurize and discharge the paper 16 inserted therebetween. At this time, the toner of the printed image adhering to the paper is melted and fixed by a heating device including a halogen lamp provided in the upper fixing roll 12. For this reason, the fixing roll is sometimes called a heat roll.

  The paper 16 is inserted and discharged in the x-axis direction in the figure, that is, in a direction perpendicular to the roll axis of the fixing roll group. At this time, if the paper to be inserted is undulated as in the region 18, the paper roll 20 in which the paper 16 is three-dimensionally folded may be formed by pressurization of the fixing roll group. In general, the paper basket 20 is often formed linearly in a direction perpendicular to the roll axis, that is, in a paper insertion / discharge direction (x-axis direction).

  The paper sheet inspection device 30 constitutes a part of the image forming system 10 and detects the paper sheet 20. The paper 16 that has undergone the fixing process by the fixing roll group is conveyed to the paper sheet inspection device 30. The direction of conveyance is the same as the direction discharged from the fixing roll group. In FIG. 1, the paper 16 that is being discharged from the fixing roll group is schematically drawn directly into the paper sheet inspection device 30, but of course, a conveyance path may be provided between them.

  The fed paper 16 is irradiated with light by an illumination unit 32 provided on the upper surface of the paper 16. The illumination unit 32 includes a one-dimensional array of LEDs (light emitting diodes) that extend perpendicular to the conveyance direction of the paper 16 and performs one-dimensional illumination on the paper 16 obliquely from above (for example, a direction of 45 °). .

  The reflected light corresponding to the irradiation is converted into an electric signal by the first imaging unit 38 composed of the lens 34 and the imaging element sensor 36 and the second imaging unit 44 composed of the lens 40 and the imaging element sensor 42, respectively. Is done. The first imaging unit 38 and the second imaging unit 44 are provided side by side in a direction perpendicular to the conveyance direction of the paper 16 immediately above the irradiated position of the paper 16. Thereby, the first imaging unit 38 and the second imaging unit 44 image the irregular reflection component of the light emitted from the illumination unit 32. The lenses 34 and 40 are lenses configured to reduce distortion, and collect the irradiated one-dimensional light beam and send it to the image sensor sensors 36 and 42. The image sensor 36, 42 includes an element such as a CCD (Charge Coupled Device) arranged one-dimensionally and converts received light into an electrical signal. This illumination and imaging are repeated a plurality of times in the process of transporting the paper 16, and the entire paper 16 is imaged. The image sensor 36, 38 is generally sufficient if it can detect luminance information, but it may be a sensor capable of detecting, for example, three colors of RGB also for image quality inspection of a printed image.

  The light emission timing of the illumination unit 32 and the imaging timings of the first imaging unit 38 and the second imaging unit 44 are controlled by the inspection image data generation unit 46. The inspection image data generation unit 46 receives the electrical signals sent from the first imaging unit 38 and the second imaging unit 44 one after another, and generates two inspection image data for the paper 16.

  The two inspection image data generated by the inspection image data generation unit 46 is sent to the detection unit 48. The detection unit 48 is a part that detects the paper sheet 20 based on the two inspection image data. The detection unit 48 includes an edge data generation unit 50, a difference data generation unit 52, and a reference setting unit 54. The edge data generation unit 50 extracts lines from the inspection image data and generates edge data. The extraction of the line can be performed by a difference filter that makes a difference between neighboring pixel values. In addition, it is desirable from the viewpoint of high-speed processing that the edge data obtained in this way is binarized based on an appropriate threshold.

  The difference data generation unit 52 generates difference data obtained by subtracting the two obtained edge data. In this process, the positions of the two edge data must match. Therefore, when the adjustment using the lenses 34 and 40 is not sufficient, the difference data is obtained after correcting the distortion of the image by data conversion or by associating a specific part such as the outer side of the paper. Generate.

  The reference setting unit 54 sets a reference value for detecting the paper web 20 based on the difference data. As the reference value, a standard value given in advance can be adopted, or it can be set by the user or automatically according to the characteristics of the paper 16. In the case of automatic setting, for example, information such as the size, thickness, and paper quality of the paper 16 is acquired from the image forming system 10, and a reference value suitable for the paper 16 is adopted according to, for example, an LUT (lookup table). Etc.

  The detecting unit 48 inspects the difference data and detects the paper sheet 20 based on the reference value. Details of the detection of the paper tray 20 will be described later.

  The display unit 56 includes a display device such as a display. When the paper tray 20 is detected, the display unit 56 displays the fact and notifies the user. Note that the paper 16 from which the paper tray 20 is detected may be automatically removed as a defective product. Further, the printing process may be automatically performed on a new sheet as a substitute for the removed sheet 16. From this point of view, it is desirable that the inspection in the paper sheet inspection apparatus 30 is performed in real time in cooperation with the image forming process.

  The user input unit 58 includes an input device such as a keyboard and is a part that receives user instructions. This instruction content is transmitted to the control unit 60. The control unit 60 controls the operation of the paper sheet inspection apparatus 30 according to a program (software). The storage unit 62 includes a storage device such as a semiconductor memory or a hard disk, and stores programs, various data, and the like.

  These various calculation functions of the paper sheet inspection device 30 are realized by defining the operation of hardware having a calculation function such as a PC (personal computer) or an ASIC (specific application integrated circuit) by a program. Can do. Further, these may be integrated with hardware or software for image forming processing in the image forming system 10 or may be configured separately.

  Next, the state of imaging of the paper bag 20 will be described with reference to FIG. FIG. 2 is a cross-sectional view in the vicinity of the AA ′ plane in FIG. 1. A paper basket 20 is formed on the paper 16. The paper 16 is illuminated by the illumination unit 32 obliquely from above. Illumination is performed from a plurality of LED elements arranged one-dimensionally. Then, the first imaging unit 38 and the second imaging unit 44 perform imaging based on this reflected light. The first imaging unit 38 and the second imaging unit 44 are provided at symmetrical positions with respect to the center of the paper 16.

  When the paper 16 does not have the paper basket 20, substantially the same data is obtained from the first imaging unit 38 and the second imaging unit 44. In other words, the geometric distortion due to the imaging position is corrected by the lenses 34 and 40, and in both cases, imaging is performed in a geometric state in which the paper 16 is orthogonal.

  However, different data is obtained near the paper tray 20 formed on the paper 16 due to the three-dimensional shape of the paper tray 20. The reflected light 70 from the paper tray 20 that reaches the first imaging unit 38 is reflected from the left side portion of the paper tray 20. And the right-hand part 72 vicinity is not imaged. On the other hand, the reflected light 74 from the paper tray 20 that reaches the second imaging unit 44 is reflected from the entire paper tray 20 around the upper portion of the paper tray 20.

  Thus, the imaging part of the paper 16 differs between the imaging in the first imaging unit 38 and the imaging in the second imaging unit 44. The difference between the imaging parts is not corrected by the lenses 34 and 40, unlike the flat part, even when all parts are imaged as well as when there are parts that are not imaged. For this reason, for example, when a print image is included in this part, the shape looks different. Further, the folded portion 76 at the apex of the paper basket 20 can be generally clearly recognized by the difference in reflection angle, but the position of the folded portion 76 looks different.

  Further, when there is a gap on the surface of the sheet 16 to be imaged, such as when the right image portion 38 is not imaged by the first imaging unit 38, the gap is different in luminance due to discontinuity of illumination conditions. In general, it can be clearly recognized. Even when there is no gap, a difference in luminance due to a difference in imaging angle between the two generally appears in the entire paper sheet 20.

  Here, the procedure for detecting the paper web 20 will be described with reference to the flowchart of FIG. 3 and the schematic diagram of FIG. First, an image forming process is performed on a sheet, and a print image is transferred (S10). Then, by passing this sheet between the fixing roll groups, the printing image is fixed by heating and pressing (S12). The illumination unit 32 illuminates the paper on which the print image is formed in this way (S14). Next, the first imaging unit 38 and the second imaging unit 44 perform imaging simultaneously (S16, S18). Imaging is sequentially performed on the paper to be fed, and the inspection image data generation unit 46 generates first inspection image data and second inspection image data based on the electrical signal obtained each time ( S20, S22).

  4A schematically shows the first inspection image data 80, and FIG. 4B schematically shows the second inspection image data 82. FIG. Both consist of substantially similar images. Specifically, the first inspection image data 80 includes a pattern area 84 of the print image and characters and squares 86, and the second inspection image data 82 also includes a corresponding pattern area 88, characters and squares. A graphic 90 is included. Further, in the first inspection image data 80, a ridge portion 94 corresponding to the paper ridge 20 is recorded, and also in the second inspection image data 82, a ridge portion 96 corresponding to the paper ridge 20 is recorded. Yes.

  Subsequently, in the edge data generation unit 50 of the detection unit 48, filter processing is performed to leave only the edge portion including the linear image to form a binary image, and edge data is formed (S24, S26). 4 (c) and 4 (d) show the first edge data 98 obtained from the first inspection image data 80 and the second edge data obtained from the second inspection image data 82, respectively. 100. In the first edge data 98, the contours of the pattern, the characters, and the square figure 86 drawn in the pattern area 84 are extracted by the filter, and the linear collar portion 94 is also extracted. Similarly, in the second edge data 100, the pattern of the pattern area 88, the outline of the character and the square figure 90, and the collar 96 are left.

  The first edge data 98 and the second edge data 100 are subtracted for each pixel, and difference data is generated (S28). FIG. 4E shows differential data 102 schematically drawn. In the difference data 102, the patterns of the pattern areas 84 and 88, the characters, and the square figures 86 and 90 are canceled and do not remain. On the other hand, in the portion where the collar portions 94 and 96 are provided, a differential collar portion 104 based on the difference between the two is described. That is, the difference collar 104 is formed by the geometric difference between the print images of the collars 94 and 96, the position of the bent part 76, the difference in luminance due to the angle difference, the difference in the presence or absence of a gap, and the like.

  The detection unit 48 analyzes the difference data 102 and detects the paper bag 20 by finding the presence of the difference paper unit 104 (S30). In general, the difference data 102 includes an edge as noise associated with a positional shift between the first edge data 98 and the second edge data 100. Therefore, the detection unit 48 detects the paper sheet 20 by comparing it with a reference value regarding survey items such as the thickness, length, direction, curvature, and luminance of the line appearing in the difference data 102. For this detection, it is also effective to acquire and use the original image data used for the image forming process, for example. For example, the detection accuracy is improved by ignoring the edges included in the edge data generated from the original image data in the analysis of the difference data 102.

  Next, a modified example of the present embodiment will be described with reference to FIGS. This modification is characterized in that a paper sheet inspection is performed using an image pickup for performing a general image quality inspection of a printed image and an image pickup for performing a gloss inspection of a sheet. FIG. 5 shows a device configuration (in the y-axis direction in FIG. 1) viewed from the side of the sheet to be conveyed. The paper 110 is irradiated with the light beam 113 from the illumination unit 112 at an irradiation angle (incident angle) α of about 45 °. The irradiated light beam 113 is reflected at a position 114, and a part of the light beam 113 is reflected as a light beam 116 having a reflection angle perpendicular to the paper 110. Then, after being reflected by the mirror 118, the light is condensed by the lens 120 and used for imaging by the RGB three-color image sensor sensor 122. The light beam 116 is suitable for inspecting the color characteristics of the position 114, and inspection image data generated based on the image pickup by the image sensor 122 is used for general image quality inspection.

  On the other hand, the light beam 124 reflected at the position 114 in the main reflection angle direction, that is, in the direction of the reflection angle α that is the same as the irradiation angle α, is reflected by the mirror 126, condensed by the lens 128, and image sensor 130 for RGB three colors. Used for imaging. The intensity of the light beam 124 in the main reflection angle direction is strongly related to the gloss of the paper 110, and the inspection image data generated based on the image pickup by the image sensor 130 is used for the gloss inspection.

  6 is a diagram depicting the apparatus configuration of FIG. 5 in the same direction as in FIG. 2, that is, the front direction in which paper is fed (from the x-axis direction in FIG. 1). The paper 110 is irradiated with light rays 113 from the illumination unit 112. Then, the light beam 116 reflected in parallel with the paper surface of FIG. 6 is bent in the depth direction of the paper surface at a position 132 where the mirror 118 is present, condensed by the lens 120, and then used for imaging by the image sensor sensor 122. In addition, the light beam 124 reflected in the main reflection direction is bent in the depth direction of the paper surface at a position 134 where the mirror 126 is located and condensed by the lens 128, and then used for imaging by the image sensor 130.

  As is clear from FIG. 6, the lens 120 and the image sensor 122 are disposed at the center of the paper 110. This position is suitable for imaging the entire sheet 110 with the highest quality, and is a preferable position for generating inspection image data used for general image quality inspection. On the other hand, the gloss inspection lens 128 and the image sensor 130, which may have relatively low accuracy, are arranged at positions close to the side surface of the paper 110. As a result, the image sensor 122 and the image sensor 130 capture images based on light beams having different angles in the horizontal direction in the drawing, that is, the roll axis direction of the fixing roll group, with respect to the same location on the paper 110. Will do. Therefore, similarly to the configuration described with reference to FIGS. 1 to 4, it is possible to accurately capture paper sheets that tend to extend in the paper feed direction.

  Finally, another modification of the present embodiment will be described with reference to FIG. The embodiment described with reference to FIGS. 1 to 4 and the embodiment described with reference to FIGS. 5 and 6 detect paper sheets by imaging from different angles. On the other hand, the embodiment described with reference to FIG. 7 is characterized in that paper sheets are detected by performing imaging from the same angle based on illumination from different angles.

  FIG. 7 shows a schematic diagram of the apparatus configuration viewed from the same direction as in FIGS. 2 and 6, that is, from the paper feeding direction, at three different times. In each of FIGS. 7A, 7B, and 7C, illumination is performed from the illumination unit 142 in which LEDs are arranged in a one-dimensional array on the paper 140. FIG. Then, the reflected light is collected by the lens 144 and used for imaging by the image sensor sensor 146.

  The arrangement of the LEDs of the illumination unit 142 is composed of three groups selected every two. That is, the arranged LEDs 150a, 150b, 150c, 152a, 152b, 152c,. . . LED 150a, 152a,. . . Form a first group and LEDs 150b, 152b,. . . Form a second group, LEDs 150c, 152c,. . . Form a third group. The LEDs in each of these groups are controlled to emit light at different timings from the LEDs in the other groups.

  In FIG. 7A, the first group of LEDs emit light. Specifically, only the LED 154a and the LED 156a emit light in the vicinity of the paper bag 160 formed on the paper 140, and light is emitted toward the paper 140 from the irradiation port on the lower surface. Each LED element has a relatively high directivity, and is installed at a height position where light does not spread so much. Therefore, the light beam from the distant LED 154a does not directly reach the left side portion 162 of the paper basket 160, and the light beam 164 from the LED 156a is behind the paper bag 160 and does not reach. For this reason, a shadow portion is formed in the left side portion 162, and this shadow portion is also recorded in data captured based on the light ray 166 from the vicinity. In addition, in the right side portion 168 of the paper basket 160, the light ray 170 from the LED 156a arrives and no shadow portion is formed.

  FIG. 7B is a diagram illustrating imaging performed next to FIG. At this stage, the second group of LEDs emit light, and the LEDs 154b and 156b emit light near the paper basket 160. And in the left part 162, the light ray 172 from LED154b has arrived, and the shadow is not formed. Moreover, in the right side part 168, the light ray 174 from LED156b has arrived, and the shadow is not formed.

  FIG. 7C is a diagram illustrating imaging performed next to FIG. At this stage, the third group of LEDs emit light, and the LEDs 154c and 156c emit light near the paper basket 160. In the left portion 162, the light beam 176 from the LED 154c has reached, and no shadow is formed. Further, in the right side portion 168, since the distance from the LED 156c does not reach because the distance is long, the light beam 178 from the LED 154c arrives and no shadow is formed.

  As described above, the three times of imaging from FIG. 7A to FIG. 7C are performed from three different angles in the roll axis direction of the fixing roll group, so that the left side portion 162 in FIG. Part can be detected. The process from FIG. 7A to FIG. 7C is sequentially repeated. In the case of repetition, by slightly transporting the paper, it is possible to finally image all the portions of the paper 140. In the imaging process of FIGS. 7A to 7C, the sheet may be moved slightly within a negligible range or a correctable range.

  For the three inspection image data generated based on the imaging result, the paper sheet 160 is inspected in the same manner as described with reference to FIGS. The comparison of the three pieces of inspection image data may be performed for all combinations, or may be performed only for a certain combination of one sheet and the remaining two sheets. Based on the comparison result, the paper sheet 160 is detected by examining the presence or absence of shadows and the difference in reflection luminance due to the difference in illumination.

  In the description of FIG. 7, the plurality of LEDs are divided into three groups. However, the grouping is not necessarily limited to three. That is, in consideration of the height, width, bending of the paper sheet 160 to be detected, the spread of light from the LED, and the like, it is particularly desirable that the trace of the paper sheet 160 is formed in the generated inspection image data. Can appropriately select the number of groupings and the interval between the LEDs to be lit so that shaded portions are formed.

It is the perspective view and functional block diagram which show the outline of the apparatus structure which concerns on this Embodiment. It is a front view of a paper-sheet inspection apparatus. It is a flowchart which shows the flow of a paper sheet inspection process. It is a schematic diagram which shows the flow of a paper sheet inspection process. It is a side view which shows a modification. It is a front view which shows a modification. It is a front view which shows another modification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Image forming system, 12 Upper fixing roll, 14 Lower fixing roll, 16 Paper, 18 area | region, 20 Paper tray, 30 Paper tray inspection apparatus, 32 Illumination part, 34 Lens, 36 Image sensor sensor, 38 1st imaging part, 40 lens, 42 imaging element sensor, 44 second imaging unit, 46 inspection image data generation unit, 48 detection unit, 50 edge data generation unit, 52 difference data generation unit, 54 reference setting unit, 56 display unit, 58 user input Unit, 60 control unit, 62 storage unit.

Claims (15)

Illumination means for irradiating the paper with light;
Imaging means for imaging the paper by reading the corresponding reflected light;
Inspection image data generation means for generating a plurality of inspection image data imaged at different irradiation angles or reflection angles with respect to the paper using the illumination means and the imaging means;
Detecting means for comparing the plurality of inspection image data and detecting paper sheets formed on the paper;
A paper sheet inspection apparatus comprising: In the paper sheet inspection apparatus according to claim 1,
The paper is a paper that has undergone an image forming process including a pressurizing process with a rotating fixing roll,
As for the irradiation angle or the reflection angle, at least the angle in the roll axis direction of the fixing roll is different from that of the paper. The paper sheet inspection apparatus according to claim 2,
The paper sheet inspection apparatus, wherein the irradiation angle or the reflection angle is equal to each other in the direction perpendicular to the roll axis of the fixing roll with respect to the paper. In the paper sheet inspection apparatus according to claim 1,
The inspection image data generating means generates inspection image data based on imaging of reflected light reflected at an equal angle and inspection image data based on imaging of reflected light reflected at an unequal angle.皺 Inspection equipment. In the paper sheet inspection apparatus according to claim 1,
The imaging means has a function of imaging from a plurality of different angles with respect to the paper,
The paper image inspection apparatus, wherein the inspection image data generation unit generates the plurality of inspection image data based on the plurality of imaging results from different angles. In the paper sheet inspection apparatus according to claim 1,
The illumination means has a function of illuminating the paper from a plurality of different angles,
The paper sheet inspection apparatus, wherein the inspection image data generation unit generates the plurality of inspection image data based on the imaging results corresponding to the plurality of illuminations from different angles. In the paper sheet inspection apparatus according to claim 6,
The illumination means includes a plurality of irradiation ports arranged in an array facing the paper, and performs illumination by classifying the plurality of irradiation ports into at least two groups and lighting them in different periods,
The paper sheet inspection apparatus, wherein the inspection image data generation unit generates the plurality of inspection image data based on an imaging result of reflected light corresponding to lighting of the irradiation ports of each group. In the paper sheet inspection apparatus according to claim 7,
The group includes three groups formed by selecting a plurality of irradiation openings in one direction at regular intervals. In the paper sheet inspection apparatus according to claim 1,
A paper sheet inspection apparatus comprising: a type processing unit that obtains information on a paper type and does not detect the paper sheet for a paper sheet having a surface with irregularities. In the paper sheet inspection apparatus according to claim 1,
A paper sheet inspection apparatus comprising setting means for setting a reference for paper sheet detection in the detection means. In the paper sheet inspection apparatus according to claim 1,
The paper sheet inspection apparatus, wherein the detection means extracts edge data from a plurality of inspection image data, compares the extracted edge data, and detects a paper sheet formed on the paper. In the paper sheet inspection apparatus according to claim 1,
The paper sheet inspection apparatus, wherein the detection means generates difference data of each inspection image data, extracts edge data from the generated difference data, and detects a paper sheet formed on the paper. . Illumination means for irradiating the paper with light;
Imaging means for imaging the paper by reading the corresponding reflected light;
A program executed in a paper sheet inspection system comprising:
An inspection image data generation procedure for generating a plurality of inspection image data imaged at different irradiation angles or reflection angles with respect to the paper using the illumination unit and the imaging unit;
A detection procedure for comparing the plurality of inspection image data to detect a paper sheet formed on the paper;
A paper sheet inspection program characterized by comprising: Illumination means for irradiating the paper with light;
Imaging means for imaging the paper by reading the corresponding reflected light;
A paperboard inspection system comprising:
An inspection image data generation step of generating a plurality of inspection image data imaged at different irradiation angles or reflection angles with respect to the paper using the illumination unit and the imaging unit;
A detection step of comparing the plurality of inspection image data to detect a paper sheet formed on the paper;
A method for inspecting a paper sheet, comprising: Illumination means for irradiating the paper with light;
Imaging means for imaging the paper by reading the corresponding reflected light;
An apparatus for controlling a paper sheet inspection system comprising:
Means for generating a plurality of inspection image data imaged at different irradiation angles or reflection angles with respect to the paper using the illumination means and the imaging means;
Means for performing detection of paper sheets formed on the paper by comparing the plurality of inspection image data;
A control device comprising: