JPH09295396A - Can printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily discover the flaw of a blanket causing the printing inferiority of a can body at its early stages by providing a judge means comparing the memory data of a standard data memory means with the image data of the blanket read by an image reading means to judge the quality of the blanket. SOLUTION: This printing apparatus E is equipped with a standard data memory means storing standard data showing such a state that ink is normally transferred to a blanket 7 from an ink bonding mechanism and a judge means comparing the standard data of the standard data memory means with the image data of the blanket 7 read by a camera 34 to judge the quality of the blanket. Printing is applied to a can body 10 from the blanket 7 and, when the printed can body is a good product, the image of the blanket 7 is stored as standard data. Thereafter, this standard data and the image data read by the camera 34 are compared and, in the case of inferiority, the printing apparatus E is stopped and a warning is emitted and, thereafter, the blanket 7 concerned is replaced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a can printing apparatus capable of inspecting a printing plate (blanket) for transferring ink onto a can body for defects.

[0002]

2. Description of the Related Art A so-called two-piece can is composed of a can lid and a cylindrical can body. The can body is subjected to DI (deep drawing, ironing) processing and washing, and then the outer surface thereof is printed. .
As shown in FIG. 4, the can printing device A has an ink attachment mechanism B.
And a can moving mechanism C. Ink adhesion mechanism B
Is composed of an inker unit 1 for supplying ink, and a blanket cylinder 8 for contacting the inker unit 1 to copy the ink and then contacting a can body 10 for printing the ink.

The inker unit 1 includes an ink source 2, a ducting roll 3, an intermediate roller 4, and a rubber roller 5.
And a plate cylinder (plate cylinder) 6, which are in contact with each other so as to sequentially receive ink from the ink source 2. On the outer peripheral surface of the blanket cylinder 8,
A plurality of blankets 7 are provided. The blanket 7 contacts the plate (not shown) formed on the outer peripheral surface of the plate cylinder 6 and also contacts the can body 10. The can moving mechanism C includes a can shooter 9 that receives the can barrel 10, a mandrel 11 that rotatably holds the can barrel 10 supplied from the can shooter 9, and a can barrel 10 that is mounted on the mandrel 11. Mandrel turret 1 for rotating and moving in the ink adhering mechanism B direction
It consists of 2.

In the can printing device A, inks of different colors from the respective ink sources 2 adhere to the plates of the plate cylinders 6 via the rolls 3 and the rollers 4 and 5, respectively. The ink is placed on the blanket 7 as an image, and the image is printed while contacting the can body 10 held by the mandrel 11.

[0005]

By the way, if the blanket 7 has stains, bleeding, or ink deficiency, defective printing occurs on the can body 10. Conventionally, the inspection of printing defects has been performed by visually observing the can body 10. However, according to this method, it takes time and labor, and it is difficult to specify which of the plurality of blankets 7 is the blanket 7 that causes a defect.

Therefore, instead of visual inspection, for example, a method in which the printed can body 10 is captured by a CCD line sensor camera and image inspection is performed by pattern matching can be considered.
However, since the printing surface of the can body 10 is a round and continuous curved surface, the starting point for capturing an image is determined (cueing).
There is a problem that it is difficult. Further, the printing failure may be caused by a defect (for example, stain) of the can body 10 itself, and it is not necessarily suitable for identifying the defect of the blanket 7.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a can printing apparatus capable of early and easily finding defects in the blanket that cause defective printing of the can body.

[0008]

According to another aspect of the present invention, there is provided a printing apparatus for a can having a plurality of rotatable rollers to which each ink is applied from a plurality of ink sources, and a plate on which ink is transferred from the rollers. Ink is transferred from a plurality of rotatable plate cylinders on the surface and plates of each plate cylinder,
And a rotatable blanket cylinder having a blanket on the outer peripheral surface for transferring the ink to the can body, image reading means for reading an image of the blanket before transferring the ink transferred from the plate to the can body, It is acceptable to compare the standard data storage means for storing the standard data indicating the state where the ink is normally transferred to the blanket with the standard data of the standard data storage means and the image data of the blanket read by the image reading means. A printing apparatus for a can, comprising: a determining unit for determining.

In the can printing apparatus according to the first aspect, since the image of the blanket before the ink transferred from the plate is transferred to the can body is read by the image reading means, it takes a longer time than the method of visually inspecting the can body. It takes no effort. Further, since the blanket is a flat curved surface having a relatively large radius of curvature, it is easier to detect an image than a can body having a small radius of curvature and a continuous curved surface. Further, since the image of the blanket is read, it is possible to determine whether the printing failure is due to a defect in the can body itself or a defect in the blanket. Further, since the judgment unit compares the standard data with the image data of the blanket read by the image reading unit to judge the quality, the blanket defect can be automatically found.

According to a second aspect of the present invention, there is provided a printing apparatus for a can.
In the can printing device described above, the determination unit includes a density detection unit that detects an abnormal density of ink by comparing with the standard data, and the density detection unit is supplied from each of the ink sources according to the result. It is characterized in that an ink amount adjusting means for adjusting the amount of ink to be generated is connected.

In the printing apparatus for a can according to claim 2, since the ink amount adjusting means adjusts the amount of ink supplied from each ink source according to the detection result of the density detecting unit, the printing defect relates to the density of the ink. In this case, the printing state automatically becomes normal.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to FIGS. 1 to 3,
An embodiment of a can printing apparatus E according to the present invention will be described. In FIG. 1, the same members as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted. A column 21 for supporting the light source 20 is provided upright in the vicinity of the blanket cylinder 8, and a camera base frame 22 is fixedly provided on the column 21. A rodless cylinder 23 is provided in the camera base frame 22, and the illumination slide base plate 24 is slid up and down by the rodless cylinder 23. The illumination slide base plate 24 is provided with an illumination attachment angle adjustment bracket 27 for adjusting the angle of the light source 20. Reference numeral 25 is a sensor bracket fixed to the pillar 21, and a fiber type photoelectric switch 26 is attached to the sensor bracket 25.

Reference numeral 30 is a camera mounting base frame, which is fixed to a body frame (not shown) by a magnet held by a magnet holder 31. The base frame 30 is provided with a camera base plate 32.
A line type light guide 33 is attached to the. A CCD line sensor camera (image reading means) 34 is provided at the tip of the line type light guide 33.

As described above, the camera 34 is firmly fixed to the main body frame by the magnet 31 via the base frame 30. This is, for example, when the camera is fixed to the tip of a pillar. Compared with this, it is for preventing an image reading error due to vibration. Reference numeral 35 denotes an image input surface cover plate, which prevents the cans from accidentally flying by the can moving mechanism C and prevents the camera 34 from making an image reading error.

As shown in FIG. 2, the blanket cylinder 8 is
On the side of the block 40 corresponding to each blanket 7
Is provided. The photoelectric switch 26 detects the block 40 to start image reading. The light source 20 and the camera 34 are arranged in the ink adhering mechanism B at positions where the image on the blanket 7 before the ink transferred from the plate is transferred to the can body 10 can be read.

Further, the printing apparatus E, as shown in FIG. 3, includes standard data storage means 50 for storing standard data indicating a state in which the ink is normally transferred from the ink adhering mechanism B to the blanket 7. The determination means 51 is provided for comparing the standard data of the standard data storage means 50 with the image data of the blanket 7 read by the camera 34 to determine pass / fail. Here, in principle,
When the blanket 7 is printed on the can body 10 and is good, the image of the blanket 7 is stored as standard data. After that, the standard data is compared with the image data read by the camera 34, and if there is a defect, the printing apparatus E is stopped or an alarm is issued. Then, the corresponding blanket 7 may be replaced.

The standard data is stored again in the standard data storage means 50 each time the blanket 7 is replaced, or the blanket 7 is cleaned or the color of the ink is changed. Since the blanket 7 is pressed against the plate when the ink is transferred, its state gradually changes. Therefore, the standard data may be stored by sampling the blanket 7 at regular intervals.

Further, the judging means 51 is provided with a density detecting section 52 for detecting an abnormality in the density of the ink as compared with the standard data, and the density detecting section 52 responds to each result in accordance with the result. An ink amount adjusting means (ink controller) 53 for adjusting the amount of ink supplied from the ink source 2 (ink fountain) is connected. The ink controller 53 adjusts the amount of ink by adjusting the pressing amount of the ink fountain 2.

In this embodiment, since the image of the blanket 7 before the ink transferred from the plate is transferred to the can body 10 is read by the camera 34, as in the prior art example,
It takes less time and effort than the method of visually inspecting the can body 10. Further, since the blanket 7 is a flat curved surface having a relatively large radius of curvature, it is easier to detect an image than the can body 10 having a small radius of curvature and a continuous curved surface. Further, because the image on the blanket 7 is read, whether the printing failure is due to a defect in the can body 10 itself, or
It is possible to determine whether the blanket 7 is defective.

Further, the judging means 51 compares the standard data with the image data of the blanket 7 read by the camera 34 and judges the quality of the blanket 7. Therefore, the defect of the blanket 7 is automatically found. be able to. Further, the density detector 52 of the determination means 51 detects the density abnormality of the ink. Then, since the ink controller 53 adjusts the amount of ink supplied from each of the ink bottles 2 in accordance with the detection result, when the printing failure is related to the density of the ink, the printing state automatically becomes normal.

In the present embodiment, the CCD line sensor camera 34 is adopted as the image reading means, but the present invention is not limited to this, and other known means may be used. . Further, the timing of re-storing the standard data in the standard data storage means is not limited to the timing shown in the present embodiment, but may be any other timing.

[0022]

According to the can printing apparatus of claim 1,
Since the image reading means reads the blanket image before the ink transferred from the plate is transferred to the can body, it takes less time and labor than the method of visually observing the can body. Further, since the blanket is a flat curved surface having a relatively large radius of curvature, it is possible to obtain an effect that an image can be detected more easily than a can body having a small radius of curvature and a continuous curved surface. Further, since the image of the blanket is read, it is possible to determine whether the printing failure is due to a defect in the can body itself or a defect in the blanket. Further, since the judgment unit compares the standard data with the image data of the blanket read by the image reading unit to judge the quality, the blanket defect can be automatically found.

According to the can printing apparatus of the second aspect, the ink amount adjusting means adjusts the amount of ink supplied from each ink source according to the detection result of the density detecting unit, so that the defective printing is caused by the ink. In the case of light and shade, the effect that the printing state automatically becomes normal is obtained.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a printing apparatus for a can according to the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a block diagram illustrating the same main part.

FIG. 4 is a front view showing a conventional can printing device.

[Explanation of symbols]

 2 Ink Source 3 Ducting Roll (Roller) 4 Intermediate Roller (Roller) 5 Rubber Roller (Roller) 6 Plate Cylinder 7 Blanket 8 Blanket Cylinder 10 Can Cylinder 34 Camera (Image Reading Means) 50 Standard Data Storage Means 51 Judgment Means 52 Darkness Detection Part 53 Ink amount adjusting means E Can printing device

Claims (2)

[Claims] 1. A plurality of rotatable rollers (3, 4, 5) to which each ink is applied from a plurality of ink sources (2), and a plate to which the ink is transferred from the rollers (3, 4, 5). Multiple rotatable plate cylinders (6)
And ink is transferred from the plate of each plate cylinder (6),
In addition, a rotatable blanket cylinder (8) having a blanket (7) on the outer peripheral surface for transferring the ink to the can body (10), and before transferring the ink transferred from the plate to the can body (10) An image reading unit (34) for reading an image on the blanket (7), and a standard data storage unit (5) for storing standard data indicating a state in which the ink is normally transferred to the blanket (7).
0) and a judgment means (51) for judging acceptability by comparing the standard data of the standard data storage means (50) with the image data of the blanket (7) read by the image reading means (34). A printing device for a can, which is characterized by being provided. 2. The can printing device (E) according to claim 1, wherein the determination unit (51) includes a density detection unit (52) for detecting an abnormal density of ink by comparing with the standard data, A printing apparatus for a can, wherein an ink amount adjusting means (53) for adjusting the amount of ink supplied from each of the ink sources (2) according to the result is connected to the light and shade detecting section (52).