WO2007077592A1

WO2007077592A1 - Printed matter inspection device

Info

Publication number: WO2007077592A1
Application number: PCT/JP2005/024041
Authority: WO
Inventors: Takanori Aoki; Mahito Matsui; Yoshitaka Hikami
Original assignee: Dac Engineering Co., Ltd.
Priority date: 2005-12-28
Filing date: 2005-12-28
Publication date: 2007-07-12
Also published as: CN101346233A; CN101346233B

Abstract

A printed matter inspection device is required to suppress flapping of sheets when an image of a printed matter is photographed to inspect the printed matter. The printed matter inspection device is provided with a means for photographing an image of a printed matter, a first air spraying means (4) for spraying air from a forward upper oblique part in a carrying direction with respect to an inspecting place to be photographed, a second air spraying means (5) for spraying air from a backward upper oblique part in the carrying direction and an air inhaling means (6) for inhaling air discharged from at least the first and second air spraying means (4) and (5)from above the inspection place defined between the first and second air spraying means (4) and (5).

Description

Specification

Printed material inspection device

Technical field

[0001] The present invention relates to a printed matter inspection apparatus that takes an image of a printed matter printed on a sheet by a photographing means and inspects the printed matter in-line.

Background art

Conventionally, an image of a printed matter that has been printed in the final unit of sheet-fed printing is taken, and it is determined whether or not the power is normally printed without smearing or chipping. In order to judge pass / fail, an image of the printed matter is taken when the printed matter is transported onto the impression cylinder of the final printing unit, or provided between the impression cylinder of the final printing unit and the paper discharge unit. Shooting when the printed material is transported on the chain transport path.

[0003] As described above, when performing an inspection based on an image of a printed material to be inspected, it is necessary to accurately photograph the image of the printed material, but when photographing a printed material on the impression cylinder, When the paper is sandwiched between the pressure and the rubber, the sheet is in close contact with the pressure, but when the sheet is detached from between the impression and the rubber cylinder. The rear edge of the sheet became free and struck, and the same force as the pressure month was also separated, making it impossible to capture accurate images.

[0004] Therefore, air was blown against the sheet on the impression cylinder toward the front and rear in the conveying direction so that the sheet was brought into close contact with the impression cylinder.

[0005] Further, when taking an image of a sheet on the chain conveyance path between the impression cylinder of the final printing unit and the paper discharge unit, it is almost horizontal and longer than the length of the sheet in the conveyance direction. The sheet was photographed at a position forming a straight line (see, for example, Patent Document 1) o

Patent Document 1: JP-A-10-166557

Disclosure of the invention

Problems to be solved by the invention

[0006] When air is blown forward on a sheet of paper that is transported on the same as the pressure month, the air force is not completely in contact with the impression cylinder even if the air is blown strongly. There was. On the other hand, when the paper is relatively thin, the flow of air blown onto the paper Because of this, lift of the paper is generated, or the air that has passed through the top surface of the paper hits the rubber cylinder, and the air that flows from the rubber cylinder enters between the paper and the impression cylinder. In some cases, it was not possible to suppress the fluttering of the image, and in particular, an accurate image of the rear end portion could not be taken.

[0007] In addition, when photographing a sheet on a horizontal conveyance path, the cost of an inspection apparatus or the like has become higher than when photographing a sheet on an impression cylinder. In addition, when printing at high speed, the moving speed of the sheet increases, so that even when moving on a horizontal conveyance path, the trailing edge may flutter, and an accurate image is taken. There were cases where it was not possible.

[0008] Furthermore, a space-saving illumination device that has a high illumination effect and can illuminate printed matter on a cylinder such as an impression cylinder has been required in order to surely capture an image to be captured.

[0009] In view of the above problems, the present invention has an object to provide a printed matter inspection apparatus that suppresses fluttering of a sheet when taking an image of the printed matter in order to inspect the printed matter. It is another object of the present invention to provide a printed matter inspection apparatus that suppresses sheet flutter and has a high lighting effect.

Means for solving the problem

[0010] The printed matter inspection apparatus according to the invention of the present application is provided with a photographing means for photographing an image of the surface to be inspected of the printed matter, in line with the printed matter inspection device that inspects the printed matter printed on the sheet. A first spraying means that blows air from the upper front of the conveyance direction to the inspection position to be photographed, and a second blowing means that blows air from the upper rear of the conveyance direction. To do.

Accordingly, the printed material can be pressed downward by the air blown from both the first spraying means and the second spraying means, and the blown air flows in the width direction and upward of the printed material, Fluttering can be suppressed.

[0011] Further, an air intake unit may be provided that inhales air discharged from the first spray unit and the second spray unit from above the inspection position sandwiched between the both spray units. Therefore, since the air discharged from the force of the first spraying means and the second spraying means is sucked in by the suction means provided between the two spraying means, the flow of air is not limited to the inspection position. It is possible to further suppress the fluttering caused by the blown air that almost never generates turbulence.

[0012] Further, the first spraying means and the second spraying means may each include a plurality of nozzles in the width direction of the printed matter, and spray uniform air in the width direction of the printed matter.

[0013] Further, the first spraying means and the second spraying means may always blow air to the inspection position to suppress the fluttering of the printed matter.

[0014] In addition, there is provided control means for controlling the start and end of air blowing by the first blowing means and the start and end of air blowing by the second blowing means, The control means terminates the spraying when a predetermined portion before the end of the printed material is transported to the inspection position, and causes the terminal force of the printed material to prevent air from entering the lower surface of the printed material. You can suppress fluttering! /.

[0015] Further, a camera constituting the photographing means is provided above the inspection position, an intake port constituting the intake means is provided at a position between the inspection position and the camera, and the inspection is performed. A photographing slit for securing an optical path between the position and the camera may be provided in the intake port.

[0016] Further, the photographing unit includes at least a reflecting mirror having a shape in which a cross-sectional shape viewed from the side surface in the conveyance direction of the printed material lacks a part of an ellipse, and a light source provided at one focal point of the ellipse. An illumination unit that is configured and a camera that captures an image of the surface to be inspected, and the other focal point of the ellipse is spaced a predetermined distance above the surface to be inspected or above or below the surface to be inspected The illumination unit may be arranged so as to be positioned.

[0017] Further, a straight line connecting the two focal points of the elliptical shape is inclined forward or backward in the transport direction with respect to the normal line of the surface to be inspected at the inspection position, and is a straight line connecting the two focal points of the elliptical shape. And the normal angle of the surface to be inspected, and the angle of reflection between the inspection position and the optical path between the camera and the normal of the surface to be inspected are substantially equal to each other. Put it down.

[0018] In addition, the photographing unit may photograph a printed material that is conveyed on a cylinder for offset printing. The invention's effect

[0019] In the printed matter inspection apparatus according to the present invention as described above, the printed matter can be pressed downward by the air blown by both the first spraying means and the second spraying means, and the printed matter flutters. This makes it possible to capture accurate images.

[0020] In addition, since the air that has been blown by both of the blowing means is sucked from the intake means provided between the two blowing means, almost no air flow occurs except near the inspection position. It is possible to take an accurate image while suppressing the fluttering caused by the blown air.

[0021] Further, since the first spraying means and the second spraying means are provided with a plurality of nozzles in the width direction of the printed matter, air can be sprayed substantially uniformly in the width direction of the printed matter, The printed material can be brought into close contact with the cylinder more reliably.

[0022] In addition, since the first spraying means and the second spraying means force is also constantly blowing air, the printed matter can be pressed downward to prevent fluttering and take an accurate image.

[0023] In addition, since the control unit starts spraying when the printed material is conveyed, and when the predetermined portion before the rear end of the printed material is conveyed to the inspection position, the spraying is ended. Since the upper surface force can be pressed down on the part where the fluttering occurs, and the spraying ends at the predetermined part before the rear end part, air does not enter the lower surface from the rear end of the printed matter, and the fluttering is suppressed. This makes it possible to take an accurate image of the printed material.

[0024] Further, by providing a camera above the inspection position, an accurate image of the printed matter can be taken, and an imaging slit for securing an optical path between the camera and the inspection position is provided. Since it is provided at the intake port, it is possible to inhale air with a force almost directly above the inspection position, and the size of the inspection device can be reduced.

[0025] In addition, the light output from the light source provided at one of the elliptical focal points is reflected by the elliptical reflecting mirror, and illuminates the inspection position (near the inspection position) serving as the other focal point of the elliptical shape. Therefore, the light reflected by the reflecting mirror that is only the direct light (regular reflected light) with the light source power illuminates the inspection position (near the inspection position), so that the inspection position (near the inspection position) is illuminated. The effect can be enhanced. In addition, since the lighting effect can be enhanced, there are few light sources. (Small), and a space-saving printed matter inspection apparatus can be obtained.

In addition, since the light reflected by the reflecting mirror illuminates the inspection position (near the inspection position) from various directions, it is possible to inspect glossy printed matter such as metal foil such as gold foil and aluminum foil.

[0026] Further, the incident angle formed by the straight line connecting the two focal points of the ellipse and the normal line of the inspection surface, the optical position between the inspection position, the camera, and the normal line of the inspection surface. Therefore, the direct light (regular reflection light) output from the light source is reflected by the surface to be inspected at the same reflection angle as the direct light incident angle. Reach the camera. In other words, the camera can capture both the specularly reflected light that also outputs the internal light source power and directly illuminates the surface to be inspected, and the irregularly reflected light that is reflected by the reflecting mirror and illuminates the surface to be inspected.

[0027] In addition, in the case of offset printing, the printed material that is conveyed on the cylinder such as the impression cylinder is photographed! / Compared with the case of photographing the printed material that is conveyed on the horizontal conveyance path. Therefore, it is possible to equip the printing press with a printed material inspection device at a low cost.

Brief Description of Drawings

FIG. 1 is a schematic view of a printing machine equipped with a printed matter inspection apparatus.

FIG. 2 is a schematic view of the printed matter inspection apparatus also viewed from the side force.

FIG. 3 is an explanatory view of the printed material inspection apparatus when the upward force is also viewed.

[Fig. 4] (a) is a graph showing the relationship between the amount of air blown out by the first blowing nozzle and its time, and (b) is the amount of air blown out by the second blowing nozzle and its time. It is a graph showing the relationship.

FIG. 5 is a cross-sectional view of a printed matter inspection apparatus including a reflecting mirror having a shape lacking a part of an ellipse.

FIG. 6 is a cross-sectional view of a printed matter inspection apparatus provided with a reflecting mirror having a shape lacking a part of an ellipse.

FIG. 7 is a cross-sectional view of a printed matter inspection apparatus including a reflecting mirror having a shape lacking a part of an ellipse and a shape lacking a part of a rectangle.

FIG. 8 is a block diagram illustrating an outline of a printed matter inspection apparatus. Explanation of symbols

[0029] 1 printing machine 2 printing unit

3 Camera 4 First spraying means

4a First blow nozzle 5 Second spray means 5

5a Second blow nozzle 6 Air intake means

6a Air intake 6b Air intake nozzle

6c Air intake part 7 Lighting part

8 Chain transport section 9 Output section

10 Rubber cylinder 11 Pressure cylinder

12 dryer 13 sheets

13a Inspected surface 14 Normal

15 Shooting slit 16 Reflector

16a 2nd focus 16b 1st focus

17 Internal light source 18 2nd slit

19 Transparent member 20 Optical path securing part

21 Transparent member 22 Judgment means

23 Multi-gradation area image creation unit 24 Master image storage unit

25 Comparison judgment unit 26 Control means

27 Reflector 27a Elliptical reflector

27b Rectangular reflector 28 Second light source

29 Projection slit

A Inspection position B Inspection position

C Inspection position

J, L Incident angle Κ, M Reflection angle

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of a printed matter inspection apparatus according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the printed matter inspection apparatus is an apparatus that is provided in a printing machine 1 for sheet-fed printing and inspects a printed matter printed by the final printing unit 2 in the printing machine 1. This printed matter inspection device The camera 3 constituting the photographing means, the first spraying means 4 for blowing air from the upper front in the conveying direction, and the air from the upper rear in the conveying direction opposite to the first blowing means 4. Second blowing means 5 for blowing air, intake means 6 for sucking air discharged from the two blowing means 4 and 5, illumination section 7 (see FIG. 2) constituting the photographing means, and the two blowing means Mainly composed of control means 26 (see FIG. 8) for controlling the means 4 and 5, and determination means 22 (see FIG. 8) for judging the print state based on the image taken by the camera 3! !

[0031] As shown in FIG. 1, the printing machine 1 is an offset printing machine for a sheet, and a printing unit 2 prints a sheet fed with a sheet feeding unit (not shown). While the chain transport unit 8 is transported, the ink transferred onto the sheet by the dryer 12 is dried and discharged from the paper discharge unit 9. In Fig. 1, there is only one printing unit 2. When printing many times, such as multi-color printing or double-sided printing, multiple printing units 2 are provided for printing. The printing unit 2 is a printing unit that is generally used in offset printing. A rubber cylinder (also referred to as an offset cylinder or a rubber blanket) that transfers ink to a sheet of paper 10, this rubber cylinder 10 It is equipped with an impression cylinder 11, a plate cylinder (not shown), etc. for conveying the sheet to the chain conveying section 8 and conveying the sheet to which the ink has been transferred.

The chain transport unit 8 is provided with a dryer 12 that dries the ink printed by the printing unit 2. When the ink is an ultraviolet curable ink, the dryer 12 irradiates the printing surface with ultraviolet rays to fix the ink on the sheet.

In this embodiment, as shown in FIG. 1, an image of a sheet (printed material) 13 (see FIG. 3) conveyed on the impression cylinder 11 of the final printing unit 2 is taken by the camera 3. However, it is determined whether or not the force is correctly printed. However, the position for photographing the sheet (printed material) 13 is not limited to the impression cylinder 11 of the final printing mute 2. It may be on the conveyance path from the impression cylinder 11 to the paper discharge unit 9. For example, an image of the sheet 13 conveyed through the chain conveyance unit 8 is shot and printing is abnormal. You may make it judge whether it is a mistake. Further, the inspection may be performed by a printing unit other than the final printing unit 2. In particular, in the case of duplex printing, the unit 2 that prints one side (for example, the front side) and the unit 2 that prints the other side (for example, the back side) can be inspected by two units. , Each unit An inspection device is installed in the printer, and when it is transported to the paper output unit 9, both sides are inspected. In addition, as shown in FIG. 1, the position where the sheet (printed material) is photographed is not limited to the impression cylinder 11, but may be on a cylinder (cylinder) such as a blank cylinder, a private cylinder, or an inversion cylinder. Good. It is desirable that the image to be shot be taken after the printing on the printing surface has been completed. However, when the surface of the printed material is coated, the image before the coating is taken. Based on the image, you can inspect it.

In the present embodiment, paper is taken as an example of printed matter, but the present invention is not limited to this, and printing is performed by a sheet-fed printing machine such as a synthetic resin sheet or a metal plate. For everything you can.

As shown in FIG. 2, the printed matter inspection apparatus illuminates the camera 3 constituting the photographing means above the inspection position A provided on the impression cylinder 11, and the inspection position A and its vicinity. It is equipped with a lighting unit 7 that lights up.

Note that the upper side of the inspection position in the claims and the specification does not mean the upper side of the printing machine 1 based on the upper and lower direction. Direction). More specifically, as shown in FIG. 2, it is the direction from the surface 13a to be inspected of the sheet (printed material) 13 to the camera 3 side. For example, as shown in FIG. 2, when the inspection position A is on a cylinder such as the impression cylinder 11, the radially outward direction from the axial center of the cylinder is above the inspection position. In addition, when the chain conveyance unit 8 shown in FIG. 1 has an inspection position, when the printed material is conveyed to the inspection position of the chain conveyance unit 8, the surface force at the inspection position of the chain conveyance unit 8 is the printed material. The direction toward the camera 3 that captures the image is above the inspection position.

In addition, the conveyance direction in the claims and the specification indicates the direction in which the printed material is conveyed as shown in FIGS. Further, the front in the transport direction (forward in the transport direction) indicates the direction (side) in the future, and the rear in the transport direction (back in the transport direction) indicates the direction (side) that has already been transported. Further, the width direction of the printed material indicates a direction perpendicular to both the transport direction and the thickness direction of the printed material.

[0034] The camera 3 may be configured to photograph the entire inspection position A with one camera according to the length of the printed material in the width direction. A predetermined interval is set in the width direction. Therefore, the plurality of cameras 3 may take images of a certain area, and the whole image in the width direction of the inspection position A may be taken. The camera 3 captures an image and may be a line sensor used in a scanner or the like. In particular, as shown in Figs. 1 and 2, etc., it is preferable to use a line sensor when photographing printed matter conveyed on the same month.

When the printed matter is photographed by the camera 3, based on the image data output from the camera 3, the determination unit 22 (see FIG. 8) determines whether there is an abnormality in printing. The determination unit 22 includes a master image storage unit 24 that stores a master image, a multi-gradation area image creation unit 23 that creates an area image from a line image captured by the camera 3, and the multi-gradation area. Compare the density level of each part of the image with the density level of the area image of the master image corresponding to the area image, and the part where the density level difference between the corresponding parts of both images exceeds the preset allowable value If there is, there is a comparison judgment unit 25 for judging the part as a defective part.

The illumination unit 7 includes a light source such as a fluorescent lamp or a light emitting diode, and illuminates at least the inspection position A.

[0036] As shown in Figs. 2 and 3, the first spraying means 4 is arranged in front of the sheet 13 in the conveying direction.

(Conveying direction) Diagonal upper force A means for blowing air in the vicinity of the inspection position B. A plurality of first blowing nozzles 4 a are provided in the width direction of the sheet 13 at substantially equal intervals. The compressed air is blown out from the first blowing nozzle 4a.

By controlling the flow rate of air blown from each of the first blowout nozzles 4a so that all the nozzles 4a, 4a have almost the same flow rate, the air is almost uniformly distributed in the width direction of the sheet 13. The sheet 13 can be brought into close contact with the impression cylinder 11 by spraying. Depending on the type of the sheet 13, the flow rate of air blown near the center in the width direction may be increased, or the flow rate of air blown near the width direction end of the sheet 13 may be increased. Good. Further, as shown in FIG. 3, the first blowing nozzles 4a, 4a may be provided so as to have substantially the same length as the width direction of the sheet 13, but the width direction of the sheet 13 The first blowout nozzle 4a may be provided longer than the length of. Depending on the type of the sheet 13, the first blowing nozzle 4a may be shorter than the length of the sheet 13 in the width direction. Further, the air blown from the first spraying means 4 may be always blown regardless of the transport position of the sheet 13, or a control means 26 (see FIG. 8) is provided as will be described later. You can control the start and end.

[0037] As shown in Figs. 2 and 3, the second spraying means 5 is provided at the rear of the sheet 13 in the conveying direction.

(Conveyor direction) Diagonal upper force A means for blowing air in the vicinity of the inspection position C, and a plurality of second blowing nozzles 5a are provided at substantially equal intervals in the width direction of the sheet 13. The compressed air is blown out from the second blowing nozzle 5a.

By controlling the flow rate of air blown from each second blowout nozzle 5a to almost the same flow rate with all the nozzles 5a, 5a, air is blown almost uniformly in the width direction of the sheet 13. Thus, the sheet 13 can be brought into close contact with the impression cylinder 11. Depending on the type of sheet 13, the flow rate of air blown near the center in the width direction may be increased, or the flow rate of air blown near the width direction end of the sheet 13 may be increased. Good. As shown in FIG. 3, the second blowing nozzles 5a, 5a, 5a may be provided so as to be approximately the same length as the width direction of the sheet 13, but the width of the sheet 13 is not limited. You may provide many 2nd blowing nozzles 5a so that it may become longer than the length of a direction. Depending on the type of the sheet 13, the second blowing nozzle 5a may be shorter than the length of the sheet 13 in the width direction.

Further, the air blown from the second blowing means 5 may be always blown regardless of the transport position of the sheet 13, or a control means 26 (see FIG. 8) is provided as will be described later. You can control the start and end.

[0038] The intake means 6 is means for sucking air blown from the first spray means 4 and the second spray means 5, and as shown in FIG. 2, the first spray means 4 And the second spraying means 5 is disposed. The air sucked by the suction means 6 passes through an air filter (not shown) to remove dust and the like, and is sprayed from the first spraying means 4 and the second spraying means 5 to the vicinity of the inspection position B and C. May be. When the intake means 6 is disposed between the inspection position A and the camera 3, an optical path between the inspection position A and the camera 3 is provided at the intake port 6 a constituting the intake means 6. Provide a shooting slit 15 to be secured. In this way, the camera 3 can take an image of the inspection position A through the photographing slit 15, and is located between the first spraying means 4 and the second spraying means 5. Since the air intake means 6 can be provided in the air-conditioner, the air blown by both the blowing means can be efficiently sucked. Further, the intake means 6 and the camera 3 can be provided above the inspection position A, and these devices (means) can be installed even in a small space.

The intake means 6 may not necessarily be provided in the printed matter inspection apparatus. That is, the air blown by the first spraying means 4 and the second spraying means 5 is directed in the width direction of the sheet 13 and above the inspection position (outward of the normal 4 of the inspection position A). You can exhaust naturally! By not providing the intake means 6 in the printed matter inspection apparatus, the printed matter inspection apparatus can be made smaller, and a low-cost inspection apparatus can be obtained.

On the other hand, if the air intake means 6 is provided, the flow of air can be controlled by sucking the blown air upward through the sheet 13, so that it can be used for a wide variety of sheets. An accurate image can be taken by reliably pressing down the sheet.

[0039] Further, when the printing press 1 is provided with a control means 26 (see FIG. 8) for controlling the start and end of spraying from the first spraying means 4 and the second spraying means 5, Based on the control signal of the control means 26, both spraying means 4, 5 are controlled. The control means 26 includes a rotation speed of the impression cylinder 11 serving as an inspection position, a position of a gripper (not shown!) That is provided on the impression cylinder 11 and sandwiches the sheet 13 between the front end (front end in the conveyance direction), Based on information such as the length of the sheet 13 in the conveying direction, a calculation process is performed to control the start and end of spraying. As shown in FIG. 2, the control means 26 is used when the front end force of the transported sheet 13 is moved to the inspection position A by a predetermined portion before the position where the spraying of the sheet 13 is finished. Spraying is started, and the spraying ends when the predetermined part before the rear end (the rear end in the transport direction) of the sheet 13 moves to the inspection position A from the predetermined part where the spraying starts. To do.

[0040] FIG. 4 (a) is a graph showing the relationship between the amount of air blown from the first blow nozzle 4a of the first blowing means 4 and the time, and point D represents the sheet 13 Indicates the time when the front end of is transported to the inspection position A. Point E indicates the time when the substantially central portion of the sheet 13 in the conveying direction is conveyed to the inspection position A, and point G indicates that the rear end of the sheet 13 is conveyed to the inspection position A. The point H indicates the time when the front end of the sheet 13 to be inspected next to the sheet 13 is conveyed to the inspection position A. That is, the first spraying means 4 Thus, the first blowing nozzle 4a does not blow air between the front end of the sheet 13 and the central portion (does not blow), and blows air between the central partial force and the rear end. (Blowing) Blow air from the rear end to the front end of the next sheet 13 (Blow).

FIG. 4 (b) is a graph showing the relationship between the amount of air blown from the second blowing nozzle 5 a of the second blowing means 5 and the time, and point D represents the sheet 13. Indicates the time when the front end of is transported to the inspection position A. Further, point E indicates the time when the substantially central portion in the transport direction of the sheet 13 is transported to the inspection position A, and point F indicates a predetermined portion before the rear end of the sheet 13 (for example, The position 40 mm before the rear edge) indicates the time when the sheet 13 is conveyed to the inspection position A, and the point H indicates that the front edge of the sheet 13 to be inspected next to the sheet 13 is conveyed to the inspection position A. The point G indicates the time when the trailing edge of the sheet 13 is conveyed to the inspection position A, and the point H indicates the leading edge of the sheet 13 to be inspected next to the sheet 13. Indicates the time of transport to inspection position A. That is, the second blowing means 5 (second blowing nozzle 5a) does not blow air between the front end of the sheet 13 and the central portion in this way (no blowing), and the central partial force rear end. Air is blown out (blowing) until the rear end force, and air is blown out (blown) between the front ends of the next sheet 13!

[0042] In the graphs shown in Figs. 4 (a) and 4 (b), control is performed so that blowing (spraying) is started when a substantially central portion in the transport direction of the sheet 13 is transported to the inspection position A. The force at the front end side (gripper side) of the sheet from the center part may be controlled to start blowing (spraying) when it is transported to inspection position A, or the sheet may be controlled from the center part. Control to start blowing (spraying) when the trailing edge (opposite the gripper) of the leaf paper is transported to inspection position A.

Further, the first spraying means 4 is controlled so as to end the blowing (spraying) when the rear end portion of the sheet 13 is transported to the inspection position A, but it is in front of the rear end portion. It may be controlled to end the blowing (blowing) at a predetermined position on the side (front end side). On the other hand, the second spraying means 5 may be controlled so as to finish the blowing (blowing) earlier than the blowing (blowing) of the first spraying means 4 ends! /, .

In the graph shown in Fig. 4 (a), air is not blown between D to E and G to H, but air with a lower flow rate than D to E and G is used. Even between ~ H Good. Similarly, in the graph shown in Fig. 4 (b), air is not blown between D to E and F to H, but air with a lower flow rate than E to F is used for D to E, F. You may spray between ~ H.

[0043] Depending on the installation position of the intake port 6a, the flow rate of the air blown (blown) from the first blowing means 4 and the angle (direction) of the blowing to the inspection position B, the second blowing Set the flow rate of air blown out from means 5 and the angle (direction) of the blow to inspection position C as appropriate. Also, depending on the type of sheet 13 (printed material) (thickness, size, material, etc.), set the flow rate of blowing (spraying) air, the spray start position, the spray end position, etc. as appropriate. .

The air intake means 6 always inhales without controlling the start and end of the blowout (spraying) like the first spraying means 4 and the second spraying means 5, but the first spraying means 6 The control means 26 may control the start and end of intake air in response to the blowout of the means 4 and the second blowing means 5. Also, the air intake amount of the air intake means 6 may be almost the same as the total amount of air blown by the two spray means 4 and 5, or a printed matter (sheets) that can be less than that. Set as appropriate according to the type (thickness, size, material, etc.) of the leaf paper 13).

[0044] As shown in Fig. 2, two blowing means 4, 5 and intake means 6 are arranged, and as shown in Figs. 4 (a) and 4 (b), the blowing of air is controlled. As a result, as shown in FIG. 3, the sheet 13 in the region shown from the inspection position B to the inspection position C is pressed against the upper force and is in close contact with the impression cylinder 11. Further, since the two blowing means 4 and 5 blow air from the front and the rear in the conveying direction, most of the air hitting the sheet 13 is above the inspection position (normal line 14 of the inspection position A). The air flowing in the width direction of the sheet 13 and flowing upward in the normal line 14 is sucked from the intake port 6a. Therefore, the air hitting the rubber cylinder 10 does not enter between the sheet 13 and the impression cylinder 11, and the back end of the sheet 13 can be suppressed from fluttering. Further, the timing at which the second spraying means 5 finishes the spraying ends earlier than the timing at which the first spraying means 4 finishes the spraying. Fluttering caused by blowing air between the rear end of 13 and the impression cylinder 11 can be suppressed. [0045] Next, the quality determination of the printed matter by the determination means 22 will be described.

As shown in FIG. 8, the determination unit 22 includes a multi-tone area image creation unit 23, a master image storage unit 24, and a comparison determination unit 25. The master image storage unit 24 stores data of a master image that serves as a reference for determining whether a printed material is acceptable. The master image data is a multi-tone area image. The multi-gradation area image creation unit 23 receives a line image signal of a printed matter photographed by a camera (line sensor), and sequentially stores the data of the line image. An area image (inspected image) is created. The comparison / determination unit 25 compares the density level of each part of the multi-tone area image with the density level of the area image of the master image corresponding to the area image, and the difference in density level between the corresponding parts of both images is determined in advance. If there is a part that exceeds the set allowable value, the part is judged as a defective part. As described above, since the pass / fail judgment is performed with a certain allowable range, it is possible to allow a slight defect that does not substantially cause a problem. Further, when comparing the multi-tone area image and the master image, it is preferable to move one or both of them on the memory (rotational movement or parallel movement) and to superimpose the two images for comparison. .

Next, as shown in FIGS. 5 and 6, the cross-sectional shape of the printed material (sheet) 13 conveyed on the impression cylinder 11 viewed from the side in the conveying direction is a shape lacking a part of an ellipse. A description will be given of the photographing means provided with an illuminating section comprising at least a reflecting mirror 16 and an internal light source 17 provided at one of the elliptical focal points 16a.

[0047] The reflecting mirror 16 is a concave mirror having a shape in which a cross-sectional shape viewed from the side surface in the conveying direction lacks a part of an ellipse. This concave mirror is made of glass and has an outer surface with silver plating. However, the concave mirror is not limited to this, and may be a concave mirror made of synthetic resin or a metal whose reflecting surface is mirror-polished. There may be. As shown in FIGS. 5 and 6, the reflecting mirror 16 has an open lower end surface (lower end side) facing the surface 13 a to be inspected of the sheet 13. The force that has two focal points on the ellipse The first focal point 16b on the side closer to the impression cylinder 11 of the reflector 16 which is one of the focal points is a sheet 13 conveyed on the impression cylinder 11. The reflecting mirror 16 is disposed so as to be substantially located on the surface 13a to be examined which is the upper surface of the surface. An internal light source 17 is disposed at the second focal point 16a, which is the other focal point. This internal light source 17 is linear or rod-shaped As the light source, for example, white diodes arranged in a row, halogen bulbs, fluorescent lamps, etc. can be used. White diodes arranged in a row are convenient as point light sources, and fluorescent lamps are low-cost and suitable for inspection of multicolored printed products with a wide spectral distribution of the light sources. In this embodiment, a fluorescent lamp is used as the internal light source 17. The internal light source 17 extends in the width direction of the sheet 13 and is disposed so as to be parallel to the inspection surface 13 a of the sheet 13. In the reflecting mirror 16 having the above-described structure, as shown in FIGS. 5 and 6, the light emitted from the internal light source 17 and reflected by the reflecting mirror 16 is reflected on the surface 13a to be inspected of the sheet 13. The first focus 16b can be focused and the inspection position can be efficiently illuminated. In FIG. 5, the first focal point 16b is a force located on the inspected surface 13a of the sheet 13. The first focal point 16b may be separated by a predetermined distance above or below the inspected position 13a. .

Further, as shown in FIG. 5, a second slit 18 for securing an optical path between the surface to be inspected 13a (inspection position A) and the camera 3 is provided in the reflecting mirror. The second slit 18 is an opening provided in the reflector 16 so as to extend in the width direction of the sheet 13 like the internal light source 17 and to be parallel to the internal light source 17. In addition, a transparent member (photographing slit) 21 for securing an optical path between the surface 13a to be inspected and the camera 3 is also provided in the intake portion 6c along the width direction of the sheet 13 like the second slit 18. Are provided. The second slit 18 is formed by opening the reflecting mirror 16, and as will be described later, the air blown to the sheet 13 by the first blowing means 4 and the second blowing means 5 is the first slit. 2 The air is sucked into the intake nozzle 6b through the slit 18. Note that the transparent member 21 is a transparent member having glass, synthetic resin and the like. Further, as shown in FIG. 5, the partial force is provided in the partial force intake portion 6c below the second slit 18 to the top of the reflecting mirror 16 so that air can be sucked from the second slit 18.

[0049] The intake means 6 shown in FIG. 5 sucks air blown from both the first blowing means 4 and the second blowing means 5 inside the reflecting mirror 16, and the air is discharged into the second air. After passing through the slit 18, the suction nozzle 6 b is passed from the suction portion 6 c, so that the sheet 13 is pressed onto the impression cylinder 11 by the air blown from both blowing means 4, 5. Can be attached. Further, the air that pressed the sheet 13 collides with the vicinity of the inspection position A, and this bumped air is sucked up almost above the vicinity of the inspection position A and passes through the second slit 18 from the inside of the reflecting mirror 16. Since it passes, it is possible to generate an air flow other than the part at the inspection position. Fluttering caused by blowing air can be suppressed. Also, the inspection position efficiently illuminates the inspection position by collecting the light emitted from the internal light source 17. The printed matter at the illuminated inspection position can be imaged through the second slit 18 and the transparent member 21. In addition, since the reflecting mirror 16 forming the illumination part is also a part of the intake means 6, the inspection apparatus can be made compact. Further, since the light reflected by the reflecting mirror 16 illuminates the inspection position A (near the inspection position) from various directions, it is possible to inspect glossy printed matter such as metal foil such as gold foil and aluminum foil.

In addition, in the inspection apparatus as shown in FIG. 6, the reflecting mirror 16 includes a flat transparent member 19 at the opening of the lower end surface (lower end side) facing the surface 13a to be inspected of the sheet 13, The transparent member 19 prevents air from entering the reflecting mirror 16. Further, in order to ensure an optical path between the inspection position A and the camera 3, the reflecting mirror 16 positioned on the optical path is provided with an optical path securing part (second slit) 20 made of a transparent material. The optical path securing unit 20 may be configured by integrating a transparent member with the reflecting mirror 16 lacking the optical path securing unit 20 by bonding or the like. When the reflecting mirror 16 has a reflective material such as silver plating on the surface of transparent glass or synthetic resin, the optical path securing portion 20 is not provided with a reflective material such as silver plating. You may comprise so that 20 may become transparent. The transparent member 19 and the optical path securing unit 20 are transparent members having glass, synthetic resin and the like, and are configured so that air does not enter the reflecting mirror 16. In addition, an outside of the reflecting mirror 16 is provided with an intake portion 6c for sucking air blown from the first blowing means 4 and the second blowing means 5, and air is provided along the outside of the reflecting mirror 16. So that the entire reflecting mirror 16 can enter the inside of the air intake portion 6c. Further, in order to secure an optical path between the inspection position A and the camera 3, a transparent member 21 is provided in the intake portion 6c located on the optical path. That is, when the camera 3 takes an image at the inspection position A, the light emitted from the inspection position A (near the inspection position A) passes through the transparent member 19, the optical path securing unit 20, and the transparent member 21 to the camera 3. And it is possible to take an image.

Further, as described above, the reflecting mirror 16 shown in FIG. 6 includes the internal light source 17 at the second focal point 16a existing on the side far from the impression cylinder 11, and the internal light source 17 is located. The straight line connecting the second focus 16a and the other first focus 16b is the inspection target at the first focus 16b (inspection position A). The sheet 13 is inclined forward with respect to a normal line (hereinafter simply referred to as a normal line) 14 with respect to the surface 13a in the conveyance direction of the sheet 13. That is, the second focal point 16a of the reflecting mirror 16 where the internal light source 17 is located is located closer to the front in the transport direction than the normal line 14. Further, an optical path securing unit 20 extending in the width direction of the sheet 13 and parallel to the internal light source 17 is provided near the top of the reflecting mirror 16 and behind the normal line 14 in the transport direction. Further, a camera 3 is provided above the outside of the reflecting mirror 16 and on the rear side in the transport direction from the normal 14. Then, the sheet 13 is inspected through the transparent member 21 provided in the intake portion 6c, the optical path securing portion 20 provided in the reflecting mirror 16, and the transparent member 19 provided in the opening at the lower end of the reflecting mirror 16. The camera 3 is arranged so that the first focus 16b on the surface 13a can be seen. Further, an incident angle J formed by a normal line and a straight line connecting the second focus 16a and the inspection position A (first focus 16b) and the inspection position A (first focus 16b) and the camera 3 are connected. The camera 3, the internal light source 17, and the like are arranged so that the reflection angle K formed by the optical path (straight line) and the normal line 14 is equal. Therefore, as shown in FIG. 6, the camera 3 outputs specularly reflected light that is output from the internal light source 17 and directly illuminates the surface to be inspected 13a, and irregular reflection that is reflected by the reflecting mirror 16 and illuminates the surface to be inspected 13a. Both light can be captured.

The second focal point 16a where the internal light source 17 is located is tilted backward in the transport direction of the sheet 13 with respect to the normal line 14, and the transport direction from the normal line 14 above the outside of the reflecting mirror 16. Camera 3 is provided at the front, and further, an incident angle J formed by a straight line connecting the second focal point 16a and the inspection position A (first focal point 16b) and a normal line 14 and the inspection position A (first focal point). Even if the reflection angle K formed by the normal line 14 and the optical path (straight line) connecting 16b) and the camera 3 is equal, the above-described effect can be obtained.

[0052] As shown in FIG. 6, when the external force air is sucked without sucking air through the inside of the reflector, the single wafer sprayed by the two spraying means 4 and 5 is used. Dust such as dust ink from the paper 13 is prevented from entering the reflecting mirror 16 by the transparent member 19. If dust such as dust or ink adheres to the transparent member 19, a clear image can be taken by wiping them off.

[0053] As shown in FIG. 5 and FIG. 6, in addition to the reflecting mirror 16 whose cross-sectional shape viewed from the side in the conveying direction is a shape lacking a part of an ellipse, as shown in FIG. Break from the side The reflecting mirror 27 is composed of an elliptical reflecting portion 27a having a shape with a part of an elliptical surface and a rectangular reflecting part 27b having a shape with a sectional shape lacking a part of a rectangle as viewed from the side force in the conveying direction. May be. The rectangular reflection part 27b is integrated with the elliptical reflection part 27a near the top of the elliptical reflection part 27a, and the width of the sheet 13 is between the elliptical reflection part 27a and the rectangular reflection part 27b. The light emitting slit 29 extending in the direction is provided. The light output from the second light source 28 extending in the width direction of the sheet 13 passes through the projection slit 29 provided at the boundary between the elliptical reflecting portion 27a and the rectangular reflecting portion 27b and passes through the surface 13a to be inspected. Illuminate. The internal light source 17 located at the first focal point 16b is disposed on the normal line. Also, the incident angle L formed by the normal line 14 and the straight line connecting the center of the second light source 28 and the inspection position A (first focal point 16b) and the optical path connecting the inspection position A (first focal point 16b) and the camera 3. The camera 3 and the second light source 28 are arranged so that the reflection angle M formed by the (straight line) and the normal line 14 is equal. By arranging in this way, the internal light source 17 positioned at the second focal point 16a can be used exclusively for the generation of irregularly reflected light captured by the force lens 3 at the first focal point 16b of the surface to be inspected 13a. On the other hand, the second light source 28 can be used exclusively for the generation of specularly reflected light captured by the camera 3 at the first focal point 16b of the surface 13a to be inspected. Therefore, by adjusting the outputs of the internal light source 17 and the second light source 28, it is possible to optimize the tolerance between the regular reflection light and the irregular reflection light captured by the camera 3.

Industrial applicability

Since it is possible to suppress the fluttering of the end portion of a sheet-like substance such as paper, cloth, or a synthetic resin sheet, it can be used in an inspection apparatus for various sheets.

Claims

The scope of the claims

[1] In a printed material inspection device that inspects printed materials printed in sheets, in-line,

While providing a photographing means for photographing an image of the surface to be inspected of the printed matter,

A first spraying means for blowing air from an obliquely upper front in the conveying direction to the inspection position to be photographed;

A printed matter inspection apparatus, comprising: a second blowing means for blowing air from a rear upper side in a conveying direction.

[2] The apparatus according to claim 1, further comprising an intake unit that sucks in air discharged from the first spray unit and the second spray unit from above the inspection position sandwiched between the two spray units. Printed matter inspection equipment.

[3] The printed matter inspection apparatus according to [1] or [2], wherein each of the first spraying unit and the second spraying unit includes a plurality of nozzles in a width direction of the printed matter.

[4] The printed matter inspection apparatus according to any one of [1] to [3], wherein the first spraying means and the second spraying means always spray air to the inspection position.

[5] Control means for controlling each of start and end of air blowing by the first spraying means and start and end of air blowing by the second spraying means, and the control means 4. The printed matter inspection apparatus according to claim 1, wherein spraying is terminated when a predetermined portion before the end of the printed matter is conveyed to the inspection position.

[6] A camera that constitutes the imaging unit is provided above the inspection position, and an intake port that constitutes the intake means is provided at a position between the inspection position and the camera, and between the inspection position and the camera. The printed matter inspection apparatus according to claim 2, wherein a photographing slit for securing an optical path is provided at the intake port.

[7] The photographing unit includes at least a reflecting mirror having a cross-sectional shape viewed from the side in the conveyance direction of the printed material and a light source provided at one focal point of the ellipse. An illumination unit configured; and a camera that captures an image of the surface to be inspected,

The illumination unit is disposed such that the other focal point of the ellipse is located on the surface to be inspected of the printed matter or above or below the surface to be inspected at a predetermined distance. The printed matter inspection apparatus according to any one of 1 to 6.

[8] A straight line connecting the two focal points of the ellipse is inclined forward or backward in the transport direction with respect to the normal of the surface to be inspected at the inspection position,

The incident angle formed by the straight line connecting the two focal points of the ellipse and the normal line of the inspection surface, and the reflection angle formed by the inspection position, the optical path between the cameras, and the normal line of the inspection surface are approximately 8. The printed matter inspection apparatus according to claim 7, wherein the cameras are arranged to be equal.

[9] The printed matter inspection apparatus according to any one of [1] to [8], wherein the photographing unit photographs a printed matter conveyed on a cylinder for offset printing.