JP4187344B2 - Print image inspection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a print image inspection apparatus for capturing and inspecting a print image while a sheet printed by a sheet-fed printing machine is being conveyed to a stacker.
[0002]
[Prior art]
As a first example of a conventional print image inspection apparatus of this type, for example, one disclosed in Japanese Patent Laid-Open No. 10-166557 is known. In this printed matter inspection apparatus, there is provided a chain conveying device provided with a substantially linear portion that conveys the printed matter from the final printing unit of the sheet-fed printing press to the paper discharge portion, and the printed matter in a state of being conveyed substantially linearly. A camera is installed at a position where image information can be taken in from.
[0003]
Specifically, as shown in FIG. 1 of the above publication, the transport chain is driven by the sprocket, but the position immediately after the engagement between the transport chain and the sprocket is released, that is, the transport chain is substantially straight. The printed image of the printed matter is inspected at a position immediately after it becomes a shape.
[0004]
As a second example of a print image inspection apparatus, when a printed product is gripped by a gripper connected to a transport chain and passes above the stacker, the printed product is released from the gripper and stored in the stacker. However, it is known that a print image is inspected at a position immediately before being stored in the stacker.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional print image inspection apparatus, in the first example, immediately after the transport chain is substantially linear, it is immediately after the transport chain is changed from circular motion to linear motion. Because of the sudden change, the gripper was shaken and it was difficult to hold the printed matter. In order to solve this problem, it is known that the transition portion between the circular motion and the linear motion of the transport chain is a relaxation curve, but this is not sufficient.
[0006]
In the second example, the rear end portion of the printed material flutters or the vicinity of the rear end portion hangs down, so that the distance between the printed surface of the printed material and the camera changes, and image input and inspection accuracy are poor. There is a problem that it ends up.
Here, it is conceivable to inspect the printed image at a stable position of the substantially linear portion of the transport chain. However, even if the printed matter is being transported by the substantially linear portion, the printed matter hangs from the gripper nail. Since the printed matter cannot be flattened, the imaging surface is not perpendicular to the optical axis of the camera, and there is a problem that the inspection accuracy is inferior because the focal length varies. Here, in order to increase the inspection accuracy as much as possible, it is conceivable that the camera and the light source are accommodated in the apparatus. Then, there is a problem that the mounting position of the camera changes and it becomes impossible to capture an image correctly. Furthermore, when paper dust or the like of printed matter adheres to the camera lens or light source, there is a problem that the optical performance deteriorates.
[0007]
Therefore, the problem to be solved by the present invention is that the optical axis of the image pickup unit is arranged so as to be surely orthogonal to the print image surface, and the focal length is kept constant by suppressing the flutter of the print image surface. It is to be able to inspect a printed image.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, the invention described in claim 1 is a printed image inspection apparatus that captures a printed image of a sheet printed by a sheet-fed printing machine for inspection,
A pair of chains that are spanned between the cylinder on the printing unit side and the stacker and that have at least a horizontal conveyance portion extending in the horizontal direction in the base body and are driven by a sprocket;
A gripping part for gripping a printed sheet that is connected to the chain and transported and disposed between the pair of chains;
An inspection surface provided between a pair of the chains and below the horizontal transport unit, through which the gripping unit transported by the chain passes,
An optical axis is arranged in a direction directly above the inspection surface and perpendicular to the inspection surface, and includes an imaging unit for capturing the print image ,
The inspection surface is higher than the inner bottom surface of the base so as to be close to the gripping portion, and a belt is provided so as to cover the side wall due to the height difference, and air is discharged to the inspection surface. air nozzle to press the leaf paper, characterized that you have provided at a position not blocking the optical path of the imaging section a between the upper and lower juxtaposed chains on the test surface.
[0009]
The invention of claim 2, in a printed image inspection apparatus according to claim 1, wherein the imaging unit is characterized in that attached to the upper outer side of the substrate covering the chain.
According to a third aspect of the present invention, in the printed image inspection apparatus according to the first or second aspect, the belt extends from the front side of the stacker in the sheet transport direction toward the inspection surface side. As described above, it is provided on the front side of the stacker and is connected to a suction portion that sucks the sheet .
[0010]
[Action]
In the invention of claim 1, the printed sheet is separated from the cylinder on the printing unit side and is gripped by a gripping portion connected to the chain. Thereby, the sheet is conveyed to the stacker side by the chain while being held by the holding unit. When the grip portion is transported to the horizontal transport portion of the chain, the sheet is mounted on the inspection surface provided on the lower side. Since the inspection surface and the grip portion are close to each other, the sheet gripped by the grip portion is disposed almost horizontally on the inspection surface. Therefore, the sheet can be made perpendicular to the optical axis of the imaging unit, the focal length can be kept constant, and the printed image on the sheet can be read with high accuracy.
[0011]
In the invention of claim 2, the image pickup unit is provided outside the base body covering the chain. Therefore, it is possible to prevent sheet paper dust from adhering to the optical system of the image pickup unit, or the attachment position of the image pickup unit to be shifted due to the contact of the sheet with the image pickup unit.
[0012]
Further, in the invention of claim 3, since the sheet passes over the belt covering the inspection surface, the step between the inspection surface and the other surface becomes gentle, and the sheet is mounted on the inspection surface. The impact can be reduced.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing the configuration of an embodiment of a printed image inspection apparatus according to the present invention. In the print image inspection apparatus of FIG. 1, the impression cylinder 11 is a final cylinder on the printing unit side, and is provided so as to rotate in contact with a rubber cylinder (not shown). A part of the outer periphery of the impression cylinder 11 is provided with a claw storage portion 11a formed in a concave cross section along its axial direction. A claw shaft (not shown) is disposed in the claw storage portion 11a in parallel with the axial direction of the impression cylinder 11, and a plurality of gripping claws 12 are attached to the claw shaft at predetermined intervals. The claw 12 is attached so that it can be opened and closed by turning an arm (not shown) once attached to the claw shaft.
[0014]
The paper take-up cylinder 13 is provided so as to rotate in contact with the impression cylinder 11, and similarly to the impression cylinder 11, a claw formed in a concave section in a part of the outer periphery along the axial direction of the paper take-up cylinder 13. A storage portion 13a is provided.
In addition, the chain 14 (two-dot chain line portion in the figure) is stretched so as to reciprocate between the impression cylinder 11 on the printing unit side and the stacker 15 for storing the sheet P after inspection. , A part of which has a horizontal conveying portion 14a extending in the horizontal direction, and is driven by sprockets 16 disposed at both ends. The sprocket 16 at one end (right side in the drawing) is connected and fixed to both ends of the paper drum 13 in the axial direction. The sprocket 16 at the other end is provided at the left end in FIG. 1 of the print image inspection apparatus. A pair of the chains 14 are provided on the front side and the back side in FIG. These chains 14 are covered with a base body 17.
[0015]
Between the pair of chains 14, a gripping portion 18 is provided for gripping the printed sheet P that is transported while being connected to the chain 14. As shown in FIG. 2, the gripping portion 18 is attached to the two hooks 18 a having both ends connected to the chain 14 and arranged side by side, and attached to the hooks 18 a. It comprises a gripper claw 18b for gripping. The claw 18b is formed so that it can be opened and closed by turning one of the two claw hooks 18a. A plurality of these gripping portions 18 are attached to the chain 14 at predetermined intervals, and are set so as to be disposed in the claw storage portion 13a of the paper take-up drum 13 when they pass through the paper take-up drum 13.
[0016]
In addition, an inspection surface 20 for the printed image of the sheet P is provided in a predetermined range below the horizontal conveying portion 14a of the chain 14 and is formed to be higher than the other portions up to a position close to the gripping claw 18b. It has been. In this embodiment, the inspection surface 20 is an upper surface of a plate-like body placed on the lower inner surface of the base body 17 that covers the chain 14. As a result, the chain 14 has a sufficient gap with the lower inner surface of the base body 17 in the horizontal conveyance portion 14a, and the gripping claw 18b does not come into contact with the chain 14 even if the chain 14 is loosened. When the claw 18b passes above the inspection surface 20, the gripper claw 18b and the inspection surface 20 have a slight gap.
[0017]
An imaging unit 21 for capturing a printed image of the sheet P is provided directly above the inspection surface 20. The imaging unit 21 is a CCD camera, for example, and is arranged so that the optical axis direction is orthogonal to the inspection surface 20. Further, a light source 22 for irradiating a printed image of the sheet P is provided in the vicinity of the imaging unit 21. The imaging unit 21 and the light source 22 are attached to the outside (upper side) of the base body 17 that covers the chain 14.
[0018]
Further, an air nozzle 23 is provided at a position that does not block the optical path of the imaging unit 21 between the chains 14 arranged vertically in the horizontal conveyance unit 14 a of the chain 14. The air nozzle 23 presses the sheet P, which is an object to be inspected, onto the inspection surface 20 by blowing air onto the inspection surface 20, and suppresses flapping of the sheet P.
[0019]
Further, an adsorption unit 24 for adsorbing the sheet P stored in the stacker 15 is provided in front of the stacker 15 in the conveyance direction of the sheet P and below the base body 17. The suction portion 24 has a length at least equal to the width of the sheet P. In addition, the adsorption | suction part 24 is movable in the left-right direction (conveyance direction of the sheet P) in FIG. This is because the suction unit 24 can be installed at a predetermined position according to the length of the sheet P. A large number of suction holes (not shown) are formed on the outer peripheral surface of the suction portion 24, and the sheet P passing over the suction portion 24 is sucked by sucking air from the suction holes.
[0020]
A plate 25 extending toward the front side in the conveyance direction of the sheet P is attached to the suction portion 24, and a belt 26 is connected to the plate 25. The belt 26 extends toward the right side in FIG. 1 and is disposed so as to cover the inspection surface 20.
[0021]
Next, the operation of the above apparatus will be described.
First, after the sheet P is printed by a printing unit (not shown), the top side of the sheet P (or the upper side of the sheet P (or by the gripping claws 12) disposed in the nail storage portion 11a of the impression cylinder 11 (or The outer edge of the ground side is gripped and conveyed while being wound around the impression cylinder 11. Although the impression cylinder 11 and the paper take-up cylinder 13 are rotating in contact with each other, the gripping claw 18b attached to the chain 14 and being conveyed passes through the portion of the paper take-up cylinder 13, and the nail of the paper take-up cylinder 13 is transferred. It is conveyed in a state of being arranged in the storage unit 13a. The holding claw 12 on the impression cylinder 11 side passes the holding claw 18b on the paper collecting cylinder 13 side. At this time, the holding claw 12 on the impression cylinder 11 side is opened to release the grip of the sheet P, and the holding claw 18b on the paper take-up cylinder 13 (chain 14) side is opened to hold the outer edge of the sheet P. After this, the gripper claw 18b is closed.
[0022]
As a result, the sheet P is replaced, and the sheet P is moved from the impression cylinder 11 side to the chain 14 side. When the chain 14 is further transported, the gripping claw 18 b is transported along the chain 14 out of the claw storage portion 13 a of the paper collecting cylinder 13. Then, the sheet P reaches the inspection surface 20 when it is transported to the horizontal transport unit 14a. The sheet P is smoothly mounted on the inspection surface 20 by sliding on the belt 26 covering the inspection surface 20. Thereby, although there is a height difference between the bottom surface inside the base body 17 and the inspection surface 20, the contact between the sheet P and the side wall of the inspection surface 20 is alleviated by the belt 26. Thereby, the corner break of the sheet P, etc. can be prevented.
[0023]
When the sheet P passes over the inspection surface 20, the gripping claw 18 b that holds the sheet P passes so as to be close to the inspection surface 20. It arrange | positions in a substantially horizontal state including the vicinity of the part currently hold | gripped by 18b. When the sheet P passes through the inspection surface 20, illumination light is emitted from the light source 22 to illuminate the printed image on the sheet P, and the printed image is read by the imaging unit 21. At the same time, since the air is discharged from the air nozzle 23 and the sheet P is pressed against the inspection surface 20, the flapping of the sheet P can be more effectively suppressed.
[0024]
The information of the read print image is transmitted to a control unit (not shown), and it is determined whether or not the print image is appropriate. For example, the print image is read together with the ID number assigned to the sheet P, and the appropriate determination result is stored in the storage unit.
As described above, since the print image can be read in a state where the sheet P is horizontally arranged by the inspection surface 20, the focal length when the print image is picked up by the image pickup unit 21 does not change, and the image pickup unit Since the optical axis 21 can be kept perpendicular to the print image surface of the sheet P, which is the image pickup surface, the print image can be inspected with high accuracy.
[0025]
In addition, since the imaging unit 21 is attached to the outside of the base 17 that covers the chain 14, the optical system of the imaging unit 21 is less contaminated with paper dust when the sheet P is conveyed. Furthermore, even if the sheet P is jammed due to a defective conveyance of the sheet P during the conveyance of the sheet P, it does not come into contact with the imaging unit 21, so the printed image surface of the sheet P is rubbed. And the sheet P is not torn, or the mounting position of the imaging unit 21 is not changed. Furthermore, maintenance of the imaging unit 21 and device adjustment are facilitated.
In addition, when the imaging unit 21 reads the printed image of the sheet P in the horizontal conveyance unit 14 a of the chain 14, the holding claw 18 b connected to the chain 14 located on the upper side passes through the optical path of the imaging unit 21. The timing is not to.
[0026]
Even after the print image is read by the imaging unit 21, the sheet P is held by the gripping claw 18b and conveyed by the chain 14. When the sheet P is conveyed to the front of the stacker 15, the sheet P is adsorbed by the adsorption unit 24, and the conveyance speed of the sheet P is reduced. That is, the suction unit 24 functions as a brake for the sheet P. Then, when the gripping claw 18 b is conveyed to the vicinity of the rear end of the stacker 15, the gripping claw 18 b controls to release the grip of the sheet P and to feed the sheet P into the stacker 15.
[0027]
In this way, by reducing the conveyance speed of the sheet P and storing it in the stacker 15, the sliding of the sheet P when it is separated from the gripping claw 18 b due to the inertial force of the sheet P is suppressed. Thus, the sheets P can be correctly stacked in the stacker 15.
After that, the gripping claw 18b is turned from the left end sprocket 16 in the right direction in the drawing and conveyed, and is sent again to the paper collecting cylinder 13 side, and enters the claw storage part 13a of the paper collecting cylinder 13, Repeat the above operation.
[0028]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made.
For example, it is also possible to form a plurality of suction holes penetrating the upper surface and the lower surface of the inspection surface 20 and to suck downward from the lower surface side of the inspection surface 20. In this case, when the inspection surface 20 is covered with the belt 26 as in this embodiment, it is effective to form the belt 26 from a material having air permeability or to form a suction hole in the belt 26. .
Further, a concave groove may be formed on the inspection surface 20, and the gripping claw 18b connected to the chain 14 may pass through the groove. In this way, the sheet P can be made more horizontal on the inspection surface 20 while reliably preventing the inspection surface 20 and the claw 18b from interfering with each other.
[0029]
According to the first aspect of the present invention, when the sheet is being conveyed by the horizontal conveyance unit of the chain, the printed image of the sheet is read by the imaging unit on the inspection surface close to the sheet gripping unit. Since it was made to do so, it is possible to read the printed image of the sheet with the optical axis of the imaging unit and the printed image surface of the sheet perpendicular to each other, and to keep the focal length constant by suppressing the flutter of the printed image, The printed image can be inspected accurately, and the belt extending from the suction part covers the inspection surface, so that the step between the inspection surface and the other surface is relaxed so that the sheet is on the inspection surface. Impact when mounted can be reduced .
[0030]
According to the second aspect of the present invention, the paper powder of the sheet adheres to the optical system of the imaging unit, or the mounting position of the imaging unit is shifted due to the contact of the sheet with the imaging unit. Can be prevented. Furthermore, maintenance of the imaging unit and device adjustment can be easily performed. Further, according to the invention of claim 3, since the belt extending from the suction portion covers the inspection surface, the step between the inspection surface and the other surface is made gentle so that the sheet is mounted on the inspection surface. The impact at the time can be relaxed and conveyed to the suction part on the near side of the stacker .
[Brief description of the drawings]
FIG. 1 is a side configuration diagram illustrating an embodiment of a printed image inspection apparatus according to the present invention.
FIG. 2 is a perspective view showing in detail a gripping part and a chain.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Pressure drum 11a Nail storage part 12 Holding claw 13 Paper collecting cylinder 13a Nail storage part 14 Chain 14a Horizontal conveyance part 15 Stacker 16 Sprocket 17 Base body 18 Grasping part 18a Claw hook 18b Holding claw 20 Inspection surface 21 Imaging part 22 Light source 23 Air nozzle 24 Adsorption part 25 Board 26 Belt P Sheet paper

Claims (3)

A print image inspection apparatus that captures a printed image of a sheet printed by a sheet printing machine for inspection,
A pair of chains that are spanned between the cylinder on the printing unit side and the stacker and that have at least a horizontal conveyance portion extending in the horizontal direction in the base body and are driven by a sprocket;
A gripping part for gripping a printed sheet that is connected to the chain and transported and disposed between the pair of chains;
An inspection surface provided between a pair of the chains and below the horizontal transport unit, through which the gripping unit transported by the chain passes,
An optical axis is arranged in a direction directly above the inspection surface and perpendicular to the inspection surface, and includes an imaging unit for capturing the print image ,
The inspection surface is higher than the inner bottom surface of the base so as to be close to the gripping portion, and a belt is provided so as to cover the side wall due to the height difference, and air is discharged to the inspection surface. air nozzle to press the leaf paper, print image inspection apparatus characterized that you have provided at a position not blocking the optical path of the imaging section a between the upper and lower juxtaposed chains on the test surface. In a printed image inspection apparatus according to claim 1, wherein the imaging unit, print image inspection apparatus characterized by being mounted on the upper outside of the substrate covering the chain. In a printed image inspection apparatus according to claim 1 or claim 2, such that the belt extends toward the inspected surface side from the front side of the stacker in the conveying direction of the sheet, the front side of the stacker A printed image inspection apparatus, wherein the printed image inspection apparatus is connected to an adsorption portion that adsorbs the sheet .

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