Lighting and inspection equipment

Abstract

The lighting device (23) irradiates light onto the conveyed coil and is provided with a light source (43) and an irradiation port (61). The irradiation port opens linearly in the width direction of the coil at the end facing the coil. The irradiation port (61) is formed between a first parallel portion (62b) and a second parallel portion (63b) of a first plate-like member (62) and a second plate-like member (63) facing each other in parallel. The linear light is irradiated onto the conveyed coil. Such a lighting device can be provided, which is capable of irradiating light only onto an inspection area of ​​a sheet or coil.

Description

Technical Field

[0001] The present invention relates to an illumination device and an inspection device including the illumination device, wherein the illumination device is configured to illuminate a pattern printed on a sheet or a roll with light. Background Art

[0002] Some conventional printers include an inspection device configured to measure the density of printed colors using a device called an inline density measuring device and determine the printing quality using the density. For example, Patent Document 1 describes a conventional inline density measuring device.

[0003] In the in-line density measuring device disclosed in Patent Document 1, a color band on a sheet-like object conveyed after printing is photographed by a camera, and the color measurement value (RGB value) of the obtained image data is converted into a converted density value by calculation. If the difference between the converted density value and a predetermined reference density value used as a judgment reference is within an allowable range, the inspection device judges that the quality is high.

[0004] In order to convert the color measurement value into the converted density value, a conversion formula is used. The conversion formula is created by using a reference density value obtained by reading a color strip using a dedicated self-propelled densitometer and the color measurement value of the image data (hereinafter referred to as a reference color measurement value) obtained by photographing the color strip with a camera. The conversion formula is an equation for calculating the reference density value from the reference color measurement value.

[0005] The image data obtained by capturing an image using a camera is affected by the pattern of the periphery of the ribbon. Therefore, if the printed pattern changes, the color measurement value of the image data captured by the camera is different from the reference color measurement value even if the ribbon is printed at the reference density value. Therefore, in this case, the color measurement value of the ribbon cannot be correctly measured, and thus the converted density value to be obtained using the conversion formula cannot be correctly obtained. Therefore, if the task of the printing press is switched and the pattern of the printed matter changes, it is necessary to recreate the conversion formula by using the reference density value obtained by reading the ribbon using a dedicated self-propelled densitometer and the reference color measurement value of the image data obtained by capturing the ribbon with the camera.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Laid-Open No. 2013-75519. Summary of the invention

[0009] Problems to be solved by the present invention

[0010] In the above conventional in-line density measuring device, since the image data obtained by capturing an image using a camera is affected by the pattern around the ribbon, a conversion formula needs to be newly created every time a printing task is switched. Therefore, the efficiency when switching printing tasks becomes low.

[0011] One object of the present invention is to provide an illumination device capable of illuminating only an inspection area on a sheet or a roll with light. Another object of the present invention is to improve the efficiency when switching printing tasks.

[0012] Means of solving the problem

[0013] In order to achieve the above-mentioned object of the present invention, there is provided a lighting device configured to illuminate one of a sheet or a coil being conveyed with light, the lighting device comprising a light source and an illumination port. The illumination port opens linearly in the width direction of the sheet or the coil at an end facing the sheet or the coil, wherein the illumination port is formed between parallel portions of a first plate-like member and a second plate-like member facing each other in parallel, and illuminates the sheet or the coil being conveyed with linear light.

[0014] According to the present invention, there is provided an inspection device, which includes: an illumination device according to the present invention; an imaging unit configured to photograph a ribbon printed on one of a sheet and a coil in a state where the ribbon is irradiated with light from the illumination device during the conveyance of one of the sheet and the coil; a type detection unit configured to detect the type of one of the sheet and the coil; an acquisition unit configured to acquire color measurement values ​​of image data photographed by the imaging unit; a storage unit configured to store correction values ​​for each type of one of the sheet and the coil; a calculation unit configured to read the correction values ​​from the storage unit and obtain a density value of the ribbon by calculation using the correction values ​​and the color measurement values ​​acquired by the acquisition unit, the correction value corresponding to the type of one of the sheet and the coil detected by the type detection unit; and a determination unit configured to determine the quality by comparing the density value with a determination reference value.

[0015] Effects of the Invention

[0016] In the present invention, only the inspection area on the sheet or coil can be illuminated with the light of the lighting device. Therefore, when photographing the ribbon, the ribbon can be photographed by the image capturing device without any influence of the pattern around the ribbon, and image data of the original color ribbon can be obtained by image capturing. Therefore, since there is no need to re-create the conversion formula when switching the printing task, it is possible to provide a lighting device capable of improving the efficiency when switching the printing task. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a side view of a web offset printing press including an illumination device and an inspection device according to the present invention;

[0018] Figure 2 is an enlarged side view of a portion of a printing press;

[0019] Figure 3 is a plan view showing the color band;

[0020] Figure 4 is a rear view showing the lighting device as seen from the camera side;

[0021] Figure 5 is a side view of the lighting device;

[0022] Figure 6 It is along Figure 4 A cross-sectional view of the lighting device taken along line VI-VI in FIG.

[0023] Figure 7 is the camera's plan view;

[0024] Figure 8 is a block diagram showing the configuration of an inspection device;

[0025] Fig. 9 is a side view of a sheet-fed offset printing press according to another embodiment;

[0026] Fig.10 is an enlarged side view showing a main body portion of a sheet-fed offset printing press; and

[0027] Fig.11 is a side view of a sheet-fed offset printing press according to yet another embodiment. DETAILED DESCRIPTION

[0028] (First embodiment)

[0029] Now refer to Figures 1 to 8 The lighting device and the inspection device according to the present invention are described in detail. In this embodiment, an example in which the present invention is applied to a web offset printing press is shown.

[0030] Figure 1 The web offset printing press 1 shown comprises a Figure 1 The leftmost coil supply unit 2 in the middle and the coil 3 is moved from the coil supply unit 2 to the Figure 1The coil 3 is conveyed on the right side of the coil supply unit 2. The infield unit 4 is provided on the right side of the coil supply unit 2, and the printing section 5 is provided on the right side of the infield unit 4. The printing section 5 prints both the front and back sides of the coil 3 through the first printing unit 6 to the fourth printing unit 9. A drying unit 10, a cooling unit 11, and a folder 12 are sequentially arranged on the downstream side of the printing section 5 in the conveying direction of the coil 3. The coil path unit 13 is provided on the upper side of the cooling unit 11. The coil 3 is conveyed from the coil path unit 13 to the folder 12.

[0031] like Figure 2 As shown, the web path unit 13 adopts a structure configured to convey the web 3 wound around a plurality of rollers 21 to the upper side. In the lower part of the web path unit 13, two lighting devices 23 and two cameras 24 are provided, and the two lighting devices 23 and the two cameras 24 form an inspection device 22 according to the present invention (see Figure 8 ). The lighting device 23 and the camera 24 are provided at two positions spaced apart from each other in the vertical direction in the web path unit 13. The lighting device 23 located at the lower side illuminates the front side of the web 3 advancing upward in the web path unit 13 with light obliquely from above. The lighting device 23 located at the upper side illuminates the reverse side of the web 3 advancing upward in the web path unit 13 with light obliquely from above.

[0032] The camera 24 located at the lower side captures the web 3 illuminated by the lighting device 23 at the lower side from the horizontal direction, and sends the image data to the control device 25 described later (see FIG. Figure 8 ). The construction of the control device 25 will be described later. The camera 24 located on the upper side photographs the web 3 illuminated with light by the lighting device 23 on the upper side from the horizontal direction, and sends image data to the control device 25. Each camera 24 is formed by a line camera, and can simultaneously photograph the web 3 from one end to the other end in the width direction.

[0033] The camera 24 according to the present embodiment captures the ribbon 26 which is disposed in the edge portion near the printing portion 3a of the web 3, as shown in FIG. Figure 3 shown. Figure 3 2 shows the end of the web 3 that has been cut. The ribbon 26 extends from the web 3 in the width direction ( Figure 3 The color patch 26a is formed by a plurality of color patches 26a arranged in the width direction and extending from one end in the left-right direction in the width direction. Each color patch 26a is printed so that a predetermined density of, for example, 100% as a color density can be obtained by the first printing unit 6 to the fourth printing unit 9.

[0034] like Figure 4 As shown, when viewed from the camera side, the lighting device 23 is formed to extend from the web 3 in the width direction ( Figure 4 The support frame 33 is an elongated shape extending from one end side in the left-right direction (in the left-right direction) to the other end side, and its two ends in the longitudinal direction are attached to the pair of frames 31 and 32 of the printing press 1 through the support frame 33. The support frame 33 is erected between the pair of frames 31 and 32 of the printing press 1, and is swingably supported by the frames 31 and 32 through the support shaft 34. The support shaft 34 is connected to the lower end of the support frame 33. Therefore, as Figure 5 As shown, the support frame 33 can be Figure 5 The solid line in the figure shows the position of use. Figure 5 The movement is swung between the retreat positions indicated by the two-dot chain lines.

[0035] Each of the frames 31 and 32 is provided with an upper stopper 35 and a lower stopper 36 to define the position of the support frame 33. The upper stopper 35 regulates the fall of the support frame from the use position to the side of the coil 3. In the use position, a joint member 37 (see FIG. 2 ) for engaging with the frames 31 and 32 is provided at the upper end of the support frame 33. Figure 4 ) is provided with a locking pin 38 detachably engaged with the engaging member 37. When the locking pin 38 is inserted into and engaged with the engaging member 37, the supporting frame 33 is maintained in the use position. When the locking pin 38 is removed from the engaging member 37 and disengaged, the supporting frame 33 can be swung from the use position to the retreat position. The supporting frame 33 according to the present embodiment includes a handle 39 to be held by both hands of an operator (not shown) when swinging.

[0036] The lower stopper 36 supports the support frame 33 that has swung to the retracted position from the lower side, and regulates the downward swing of the support frame 33 from the retracted position.

[0037] like Figure 6 As shown, the lighting device 23 is equipped with a box-shaped shell 41, a shading member 42, a light-emitting device 44, etc. The shell 41 has an opening located on one side thereof, and the shading member 42 is attached to the opening of the shell 41; the light-emitting device 44 includes a light source 43 and is accommodated in the shell 41.

[0038] like Figure 4 As shown, the housing 41 is formed to be longer in the width direction of the coil 3. In the longitudinal direction of the coil 3, the length of the housing 41 is longer than the width of the coil 3. The two ends of the housing 41 in the longitudinal direction are connected by brackets 45 (see Figure 5 ) is attached to the support frame 33. The housing 41 is attached to the bracket 45 by threading a plurality of attachment bolts 46 extending through the bracket 45 into the housing 41, as shown in FIG. Figure 5 In the present embodiment, an arc-shaped long hole 47 configured to allow the attachment bolt 46 to pass therethrough is formed in the bracket 45 so that the attachment angle of the housing 41 can be changed.

[0039] like Figure 6As shown, the light shielding member 42 includes an irradiation port 61 at the end of the light shielding member 42 facing the coil 3, and the irradiation port opens linearly in the width direction of the coil 3. The light shielding member 42 according to this embodiment includes: a first plate-shaped member 62, Figure 6 Which is attached to the upper portion of the housing 41; and a second plate-like member 63, in Figure 6 It is attached to the lower part of the housing 41.

[0040] The pair of first and second plate members 62 and 63 is formed by bending plates made of metal so that the plates are parallel to each other. In addition, the first and second plate members 62 and 63 are formed to have the same length as the case 41 in the width direction of the coil 3.

[0041] In addition, the first plate-like member 62 and the second plate-like member 63 include: a first reflecting portion 62a and a second reflecting portion 63a, which are inclined so that the interval between the plate-like members 62 and 63 gradually narrows from the side of the light source 43 to the irradiation port 61; and a first parallel portion 62b and a second parallel portion 63b, which extend from the far ends of the first reflecting portion 62a and the second reflecting portion 63a parallel to the optical axis C of the light-emitting device 44.

[0042] The irradiation port 61 is formed between a first parallel portion 62 b and a second parallel portion 63 b of the first plate-like member 62 and the second plate-like member 63 facing each other in parallel.

[0043] The interval between the first parallel portion 62b and the second parallel portion 63b (i.e., the opening width D2 of the irradiation port 61 in the direction perpendicular to the width direction of the web 3) is greater than the width D1 of the ribbon 26 in the direction perpendicular to the width direction of the web 3 (see Figure 3 Therefore, a linear light narrower than the width D1 of the color ribbon 26 is emitted from the irradiation port 61.

[0044] The light emitting device 44 includes a light source 43 , a lens 64 located on the opening side of the housing 41 ; and an air blowing member 65 located near the light source 43 .

[0045] The light source 43 is formed of a plurality of LEDs 43a. The LEDs 43a are mounted on the substrate 66 so that the optical axis C is perpendicular to the substrate 66, and are arranged at predetermined intervals throughout the entire area in the longitudinal direction of the housing 41.

[0046] The lens 64 is configured to diffuse the light from the light source 43 to the entire area in the light shielding member 42. A portion of the light diffused by the lens 64 is directly transmitted to the irradiation port 61, and most of the remaining light is reflected by the first reflecting portion 62a and the second reflecting portion 63a and sent to the irradiation port 61. Therefore, the light is emitted from the irradiation port 61 in a direction parallel to or almost parallel to the optical axis C, and the web 3 is irradiated with linear light having a narrow width in a direction orthogonal to the width direction.

[0047] The air blowing member 65 blows air sent from an air supply source (not shown). The air blowing member 65 is provided on both sides of the LED 43a and supported by the housing 41 so that air blows to the LED 43a. When the air blows to the LED 43a, the LED 43a is cooled. It should be noted that Figure 6 As shown by the two-dot chain line in FIG. 6 , the air blowing member 65 may be arranged to blow air to the back side of the substrate 66 .

[0048] Since the air blown out from the air blowing member 65 passes inside the light shielding member 42 and is discharged from the irradiation port 61 to the outside of the lighting device 23, the air is blown out from the irradiation port 61. The air always flows near the irradiation port 61. This prevents dust generated from the web 3 or ink mist generated in the first printing unit 6 to the fourth printing unit 9 from entering the light shielding member 42 through the irradiation port 61 and attaching to the lens 64 or the light source 43, or attaching to the distal end of the irradiation port 61 and blocking the irradiation port 61.

[0049] like Figure 7 As shown, the camera 24 is attached to a support member 67 erected between a pair of frames 31 and 32 of the printing press 1 and is arranged at a position corresponding to the center portion in the width direction of the web 3 .

[0050] like Figure 8 As shown, the inspection device 22 includes: a part of the control device 25 configured to control the operation of the printing press 1, the above-mentioned lighting device 23 and camera 24, a self-propelled densitometer 71 to be described later, a display device 72, etc. The self-propelled densitometer 71 reads the ribbon 26 (which is used as a ribbon for each printing portion 3a (see Figure 3 ) is used to measure the density of each color patch 26a based on the image data obtained by the image capturer. The measurement result is sent to the control device 25 as a reference density value. The display device 72 displays the operating status of the printing press 1, various alarms, etc.

[0051] The control device 25 includes a printing section 73, an inspection section 74, a storage unit 75, and a determination unit 76. The printing section 73 controls the operation of a drive motor (not shown) and various actuators of the printing press 1.

[0052] The detection section 74 includes an illumination section 81 , an imaging unit 82 , an acquisition unit 83 , a calculation unit 84 , and a type detection unit 85 .

[0053] The lighting section 81 switches on / off the light source 43. The imaging unit 82 includes the camera 24, a circuit (not shown) configured to control an image capturing operation of the camera 24, and the like, and the camera 24 captures the ribbon 26 during the conveyance of the web 3.

[0054] The acquisition unit 83 acquires color measurement values ​​(RGB values) of the image data captured by the camera 24. The image data is image data of each color patch 26a of the color bar 26.

[0055] The calculation unit 84 performs calculation using a conversion formula 86 prepared in advance and a correction value 87 stored in the storage unit 75. The conversion formula 86 is an equation for calculating a reference density value measured by the self-propelled densitometer 71 based on a reference color measurement value obtained by photographing a color ribbon 26 by the camera 24, which is similar to the reference color ribbon 26 measured by the self-propelled densitometer 71. As the conversion formula 86, an equation similar to the equation described in, for example, Japanese Patent Publication No. 2013-75519 previously applied by the applicant of the present invention can be used. When the conversion formula 86 is used, a density value can be converted from a color measurement value obtained by photographing a color ribbon 26 that is not a reference. Hereinafter, the density value obtained by calculation will be referred to as a "converted density value."

[0056] The correction value 87 is determined for each type of the web 3. If the type of the web 3 changes, even if printing is performed at the same density, the density value changes according to the converted density value based on the color measurement value obtained by the camera 24 through image capturing. The correction value 87 is a value for correcting the calculation result that changes due to the type of the web 3. That is, when the calculation unit 84 performs calculation using the color measurement value of the actual image data obtained by the camera 24 through image capturing, the above-mentioned conversion formula 86, and the correction value 87, a corrected converted density value corrected by the correction value 87 is obtained.

[0057] Data on the type of the web 3 is included in the basic data, and the basic data will be used by the printing section 73 to control the printing operation. The type detection unit 85 reads the data on the type of the web 3 from the basic data.

[0058] The storage unit 75 stores the above-mentioned correction value 87 for each type of the web 3 as a correction processing table.

[0059] For each color patch 26a, the determination unit 76 compares the corrected converted density value with a predetermined reference density value (determination reference value) used as a predetermined determination reference. If the difference between these values ​​is within the allowable range, the quality is determined to be high. If the difference is outside the allowable range, the quality is determined to be poor. The determination unit 76 displays the quality determination result on the display device 72.

[0060] In the printing machine 1 including the inspection device 22 configured in this way, when printing is performed on the web 3, the ribbon 26 is photographed by the camera 24 in the web path unit 13, and the determination unit 76 determines the quality of the ink density based on the image data obtained by the image capture.

[0061] The quality judgment is performed by the judgment unit 76 by comparing the corrected converted density value with the reference density value used as a judgment basis, and the corrected converted density value is obtained by the calculation unit 84 using the color measurement value of the actual image data obtained by the camera 24 through image capture, the conversion formula 86 and the correction value 87 corresponding to the type of the current roll 3.

[0062] If the ink supply amount in the first printing unit 6 to the fourth printing unit 9 does not change, even if the pattern printed on the web 3 changes, the color measurement value of the actual image data obtained by image capture using the camera 24 does not change. This is because the lighting device 23 illuminates the ribbon 26 on the web 3 with linear light, and only the ribbon 26 can be illuminated with the light of the lighting device 23. Therefore, the ribbon 26 can be captured by the camera 24 without any influence of the pattern around the ribbon 26, and the image data of the original color ribbon 26 can be obtained by image capture.

[0063] Even if the pattern changes, the color measurement value of the image data captured by the camera 24 does not change, which means that there is no need to perform the conversion formula re-acquisition performed in the conventional device. Therefore, according to this embodiment, since there is no need to re-acquire the conversion formula when the printing task is switched, it is possible to provide a lighting device that can improve the efficiency when switching the printing task.

[0064] The irradiation port 61 according to the present embodiment is formed between the first parallel portion 62b and the second parallel portion 63b which face each other in parallel with the first plate-like member 62 and the second plate-like member 63. Therefore, since light which is not parallel or almost not parallel to the optical axis C is shielded by the first plate-like member 62 and the second plate-like member 63, the ribbon 26 is irradiated with substantially parallel light.

[0065] As a result, only the ribbon portion is illuminated with the light of the lighting device 23, and the image data is never affected by the stray light of the pattern from the periphery of the ribbon 26. Therefore, accurate density measurement can be performed, and the frequency of re-obtaining the conversion formula can be reduced. Therefore, it is possible to prevent the web 3 from being wasted and save the working time required for preparation until actual printing.

[0066] The lighting device 23 according to the present embodiment includes the air blowing member 65. Therefore, dirt such as ink mist or dust can be prevented from adhering to the lens 64, the light source 43 or the irradiation port 61, and the maintenance frequency can be reduced, and high inspection performance and density measurement performance can be maintained.

[0067] Furthermore, since the lighting device 23 includes the air blowing member 65 , it is possible to suppress brightness variation by cooling the light source 43 (LED 43 a ) with cooling air.

[0068] The first and second plate-like members 62 and 63 according to the present embodiment include first and second reflecting portions 62a and 63a which are inclined such that the interval between the plate-like members 62 and 63 gradually narrows from the light source 43 side toward the irradiation port 61.

[0069] Therefore, since the color ribbon 26 can be irradiated with strong (bright) light from the irradiation port 61, the brightness difference between the color ribbon 26 and the surrounding pattern becomes larger, and the image data is less affected by the surrounding pattern in image capture. Therefore, a density value close to the reference density value measured by the self-propelled densitometer 71 can be obtained using the camera 24, and the reliability of the determination result obtained by the determination unit 76 becomes higher.

[0070] The opening width D2 of the irradiation port 61 according to the present embodiment in the direction perpendicular to the width direction of the web 3 is narrower than the width D1 of the color ribbon 26 in the direction perpendicular to the width direction of the web 3. According to the lighting device 23, only the color ribbon 26 is irradiated, and a stable slit light source is generated. Therefore, the accuracy of density quality determination becomes higher.

[0071] In the inspection device 22 according to the present embodiment, if the printing job is changed and the type of the web 3 is changed, the type detection unit 85 detects the type of the new web 3. Then, the calculation unit 84 obtains a corrected converted density value corresponding to the new web 3 by using a correction value 87 according to the type of the web 3, a color measurement value obtained by photographing the color ribbon 26 printed on the new web 3 using the camera 24, and a conversion formula 86.

[0072] Therefore, according to the present embodiment, not only can density measurement be performed without correction processing when the printed material (web 3) does not change and only the pattern changes, but also density measurement can be performed without correction processing when the printed material changes.

[0073] (Second embodiment)

[0074] The lighting device can be configured as Fig. 9 and Fig.10 As shown. Fig. 9 and Fig.10 Zhongyu Figures 1 to 8 The same reference numerals in the drawings denote the same or similar components, and their detailed description will be appropriately omitted.

[0075] Fig. 9 The printing press 91 shown is a sheet-fed offset printing press and is Fig. 9 A sheet supply unit 93 is provided at the right end portion in the middle, and the sheet supply unit is configured to supply the sheet 92. The printing machine 91 includes: a printing section 100, which includes a first printing unit 94 to a sixth printing unit 99; a coating unit 101, which is located at the downstream side of the printing section 100 along the conveying direction of the sheet 92; and a sheet discharge unit 103, which is configured to dry the sheet 92 coated by the coating unit 101 and discharge the sheet 92 to the discharge pile 102. The first printing unit 94 to the sixth printing unit 99 print on one surface of the sheet 92.

[0076] In this embodiment, the lighting device 23 according to the present invention is arranged at a position facing the impression cylinder 104 in the coating unit 101. Fig.10 As shown, the lighting device 23 according to the present embodiment is arranged directly above the impression cylinder 104, and illuminates the upper surface (printing surface) of the sheet 92 conveyed by the impression cylinder 104 with linear light. The camera 24 is provided at a position spaced upward from the impression cylinder 104.

[0077] In this embodiment, the color band 26 on the sheet 92 can be photographed by the camera 24 without any influence of the surrounding pattern. Therefore, according to this embodiment, the efficiency when switching the printing task of the sheet-fed offset printing press 91 becomes higher.

[0078] (Third Embodiment)

[0079] You can Fig.11 The lighting device is configured as shown. Fig.11 Zhongyu Figures 1 to 8 The same reference numerals in the drawings denote the same or similar components, and their detailed description will be appropriately omitted.

[0080] Fig.11 The printing press 111 shown is a sheet-fed offset printing press and is Fig.11 A sheet supply unit 113 is provided at the right end portion in the figure, and the sheet supply unit is configured to supply the sheet 112. The printing press 111 includes: a printing section 114, which is configured to perform double-sided printing; an inspection section 115, which is provided on the downstream side of the printing section 114 along the conveying direction of the sheet 112; and a sheet discharge unit 120, which is configured to convey the sheet 112 inspected by the inspection section 115 using a chain conveyor 116, and discharge the sheet to a plurality of conveying piles 117-119.

[0081] The printing section 114 includes first to fifth surface printing units 121 to 125 configured to print on the front side of the sheet 112 , and first to fifth back side printing units 126 to 130 configured to print on the back side of the sheet 112 .

[0082] The inspection section 115 includes an upstream-side surface inspection unit 131 , an upstream-side back-side inspection unit 132 , a downstream-side surface inspection unit 133 , and a downstream-side back-side inspection unit 134 .

[0083] The upstream side surface inspection unit 131 and the upstream side back side inspection unit 132 use the visible light camera 135 to perform the inspection of the printing quality of the sheet 112 and the density inspection of the ribbon 26. In the present embodiment, the lighting device 23 according to the present invention irradiates the sheet 112 with linear light to be photographed by the visible light camera 135. The visible light camera 135 is the same as the camera 24 used when the first embodiment is adopted.

[0084] The downstream side surface inspection unit 133 and the downstream side back side inspection unit 134 inspect the printing quality of the sheet 112 using the ultraviolet camera 136 .

[0085] According to this embodiment, the ink density can be checked on both the front and back sides of the sheet 112. In addition, since the ribbon 26 can be photographed by the visible light camera 135 without being affected by the pattern around the ribbon 26, the efficiency when switching the printing task of the sheet-fed offset printing press 111 becomes higher.

[0086] In the above-mentioned embodiment, an example has been described in which the lighting device according to the present invention is used in a density inspection device configured to photograph a ribbon and inspect the density of ink. However, the lighting device according to the present invention is not limited to this example, but can be used in a pattern inspection device configured to inspect the presence / absence of a printing fault such as printing omission or dirt adhesion in a printed pattern portion. Even in this case, a linear narrow area serving as an inspection area is irradiated with light, thereby emphasizing the inspection area without any influence of the pattern in the non-inspection area, and compared with the conventional inspection in which a wide range is irradiated with light, a printing fault can be accurately detected.

[0087] Description of Reference Numerals

[0088] 3 Coil

[0089] 23 lighting fixtures

[0090] 43 Light Source

[0091] 61 irradiation port

[0092] 62 first plate-like member

[0093] 62b First parallel section

[0094] 63 Second plate-like member

[0095] 63b Second parallel section

[0096] 92, 112 sheets.

Claims

1. An illumination device configured to illuminate an inspection area on a conveyed sheet or coil with light, the illumination device comprising: light source; as well as a light shielding member having an illumination port, the illumination port opening in a straight line, Wherein, the light shielding member includes a first plate-shaped member and a second plate-shaped member, The first plate-shaped member and the second plate-shaped member include a first parallel portion and a second parallel portion, respectively. The first parallel portion and the second parallel portion face each other in parallel, The irradiation port is formed between the first parallel portion and the second parallel portion, The opening width of the irradiation port in the direction perpendicular to the width direction of the sheet or the coil is narrower than the width of the inspection area in the direction perpendicular to the width direction of the sheet or the coil, and The first parallel portion and the second parallel portion extend parallel to the optical axis of the lighting device, so that the linear parallel light emitted from the irradiation port irradiates only the inspection area on the sheet or the coil being conveyed. 2 . The lighting device according to claim 1 , further comprising an air blowing member for supplying cooling air to the light source.

3. The lighting device according to claim 1 or 2, wherein: The first plate-shaped member and the second plate-shaped member further include a first reflecting portion and a second reflecting portion, respectively, each of the first reflecting portion and the second reflecting portion being configured to reflect a portion of the light from the light source, The first reflecting portion and the second reflecting portion are inclined so that the interval between the first plate-shaped member and the second plate-shaped member gradually narrows from the light source side toward the irradiation port.

4. An inspection device, the inspection device being configured to determine the quality of a printed matter, the inspection device comprising: The lighting device according to claim 1 or 2, wherein the lighting device is configured to illuminate a ribbon printed on one of a sheet material and a coil material being conveyed with light; an imaging unit configured to photograph the color ribbon illuminated by the light of the illumination device; an acquisition unit configured to acquire a color measurement value of the image data captured by the imaging unit; a calculation unit configured to calculate a density value of the color band using the color measurement value acquired by the acquisition unit; as well as a determination unit configured to determine the quality by comparing the density value with a determination reference value, Wherein, the lighting device illuminates the color ribbon with linear light.

5. The inspection device according to claim 4, further comprising: a type detection unit configured to detect a type of one of the sheet material and the roll material; and a storage unit configured to store a correction value for each type of one of the sheet material and the coil material; The calculation unit is configured to read a correction value from the storage unit and calculate a density value of the color ribbon using the correction value and the color measurement value acquired by the acquisition unit, the correction value corresponding to the type of one of the sheet and the roll material detected by the type detection unit.

Images