JPS6112342A - Apparatus for inspecting printed matter - Google Patents

Abstract

PURPOSE:To stabilize inspection, by preventing the rear end of printing paper from jumping by providing a paper pressing mechanism. CONSTITUTION:Printing paper 1 receives inspection as is closely contacted with a rotary final impression cylinder 8 in such a state that the front end thereof is fixed to the final impression cylinder 8 by the holding pawl 5 on said cylinder 8. Because the printing paper 1 becomes free at the rear end thereof at the point of time when said paper 1 is released from the contact pressure for printing between a rubber cylinder 3 and the final impression cylinder 8, immeidately before the freeing, said rear end is pushed to the final impression cylinder 8 by a paper pressing mechanism 14 to keep the close contact with the impression cylinder 8. The operation of this paper pressing mechanism 14 is controlled by CPU16. In such a state that the printed matter 1 is illuminated by an illuminator 13, the image information of the reflected light from the picture pattern printed on the printed matter 1 is taken in from an input camera 11 comprising a CCD camera as an image signal IS. The inputted image signal IS is digitalized by an A/D converter 15 and the image signal, when an operator judged that said printed matter was a normal one, is stored in reference memory 19 as a reference signal and the inspection of the printed matter is perfomred by the comparison with said reference signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed matter inspection device for in-line comparing the state of a printed matter being printed with a standard state in a printing press to detect abnormalities in the printed matter.

Conventionally, the mainstream method for inspecting printed matter has been offline and relying on human vision. Is this a printed item?
This comes from the fact that the dot patterns are different, and the subtle differences in inspection items on printed matter that require reliance on human vision have been thought to be a problem. On the other hand, in response to the desire to evaluate printed matter while it is being printed, attempts have been made to use strobe lighting synchronized with the printing speed and to judge printed matter as a still image by using mirrors that rotate synchronously at high speed. It was done. However, these methods were not systems that could be called inspection machines in that they relied on human vision for inspection. In addition, attempts have been made to print a color punch at the same time as the pattern on the printed matter and inspect the color patch, thereby inspecting the printed matter. However, with this method, if a printing problem (oil dripping, stains, etc.) occurs in the pattern area, it will be overlooked, and it could not be said that the function of the inspection machine was fully fulfilled.

On the other hand, a system has recently been proposed in which printed matter is inspected in-line using a line sensor, as seen in Japanese Patent Application No. 57-220515 titled "Print Inspection Apparatus." By using this method, the pattern itself of the printed matter can be automatically inspected in-line, so it does not have the above-mentioned drawbacks and can be expected to have excellent effects as an inspection machine. However, the above invention is not without its problems. For example, in the case where a print inspection device is installed in a sheet-fed printing machine, the method of conveying the printing paper in the sheet-fed printing machine is such that only the leading edge of the printing paper is gripped by a claw. Since the trailing edge of the printing paper is completely free when it is fixed by simply holding it in place, the positional relationship between the detection unit in the print inspection device and the inspection surface of the printing paper becomes unstable, and this makes it difficult to inspect. It was considered difficult to apply this system to sheet-fed printing presses due to the problem of reduced accuracy. This problem will be explained in more detail with reference to FIG. 1, which is an explanatory diagram showing the conveyance state of printing paper in a sheet-fed printing machine.

In Fig. 1, 2 indicates the printing paper conveyed from the paper feed section (not shown) (11 is the gripping claw (5) provided on the impression cylinder (2)).
The front end of the sled is bitten, and the transfer by rotation of the impression cylinder f21, the transfer to the bite claw (51) provided on the transfer cylinder (6), and the transfer by rotation of the transfer cylinder (6) are repeated. As a result, the paper is conveyed to the paper discharge section.

The printing paper 11) is transported between the impression cylinder (2) and the blanket cylinder (3).
), it becomes pressurized and the ink transferred from the plate cylinder (4) to the blanket cylinder (3) on its surface is pressed onto the printing paper (1), making printing possible. becomes. In fact, multicolor printing allows for multiple prints.

In reality, in multicolor printing, a predetermined printed product is obtained by repeating the above steps in a plurality of printing units. By the way, inspection of printed matter is usually performed when printing is completed, so the appropriate installation location for the printed matter inspection device is the final printing unit (71 or later). Possible locations include when the printing paper 111 is being conveyed by the claws on the chain (9) (arrow B) and when the printing paper 111 is being conveyed at the paper ejection section.
It is possible to consider the point at which the sheets are piled up (arrow C), but in reality there are many problems due to the influence of the powder to prevent ink from spilling and the instability of the chain conveyance. Final impression cylinder (8) corresponding to
It is considered that the most appropriate examination is at the rear and upper part (arrow A). There is also a method of installing a unique inspection unit next to the printing unit, but this requires large-scale equipment and has many problems in terms of cost.

Considering the inspection at the upper rear part (arrow A) of the final impression cylinder (8), it is only necessary to install the detection part of the print inspection device (for example, the illumination light source and camera unit) at that position, which saves space. There is no problem with that. However, depending on the printing machine, there are models where the space is even more limited, and in that case, one problem of installation space can be overcome by using means such as optical fibers or contact type line sensors. However, when inspecting printed matter at the arrow A section, there are the following problems.

That is, while the front end of the printing paper (11) is bitten by the gripping claw and the impression cylinder and the blanket cylinder are applying printing pressure to a part of the printing paper, the printing paper (11) is under pressure. Because it is in close contact with the impression cylinder, the relative position of the input information in pixels during inspection is stable. Although it is fixed with a claw or a claw on the chain, if the other parts of the printing paper are completely free, the trailing edge of the printing paper becomes unstable and may not touch the impression cylinder (8). This results in phenomena such as floating or waving due to poor adhesion, making accurate inspection impossible.

Here, if the printing paper is limited to thin paper with a paper thickness of about 0.1%, an air blowing port (101) is provided above the final impression cylinder (8) as shown in FIG. The above problem can be solved by blowing air in a direction that brings (1) into close contact with the impression cylinder (8), but with thick paper exceeding approximately 0.2 ] 1 on the final impression cylinder (8).For this reason, when using thick paper, the trailing edge of the printing paper will jump up, and the image information taken in from the detection unit of the print inspection device will not be printed properly. The paper is in an unstable state near the trailing edge, making the desired inspection impossible.The present invention was made to solve the above-mentioned problems, and is aimed at preventing the jumping of the trailing edge of printing paper in sheet-fed printing machines. □The present invention provides a printed matter inspection device that eliminates inspection-inhibiting factors such as rise-up and enables accurate inspection on sheet-fed printing presses.

The present invention will be described below based on embodiments shown in the drawings. FIG. 6 is an explanatory diagram of one embodiment of the printed matter inspection apparatus of the present invention, in which the printing paper (1) is fixed at its front end by the gripping claw (5) K on the final impression cylinder (8). , the inspection is carried out in close contact with the rotating final impression cylinder (8). Printing paper (
] 1 is pressed when released by the printing contact pressure of the blanket cylinder (3) and the final impression cylinder (8) as described above,
Close contact with the impression cylinder (8) is maintained. This paper holding mechanism (1
The operation of 41 is controlled by the CPU (161), but the details will be explained later based on FIG. In the illuminated state, image information of reflected light from the pattern printed on the printing paper IJl is taken in as an image signal IS from an input camera circle consisting of a C'CD camera or the like. The start timing and sampling timing of signal acquisition with this input camera (older) are the final impression cylinder (older).
8) Based on the timing pulse TP from the pulse generator az attached to the plate cylinder, blanket cylinder, etc., the CPU (161) performs control.The input image signal IS is digitally converted by the A/D converter 051. The image signal when the operator judges that the printed material is normal is stored as a reference signal in the reference memo! It is performed by comparing with this reference signal.Comparative inspection methods include differential, differential, and integral processing, but they can be applied as appropriate to ensure that the error with normal printed matter is within the allowable range. The printed matter is determined to be an abnormal printed matter.In such processing, if high-speed processing is required due to the relationship between printing speed and amount of information]
- A method of performing the above processing in a - mode configuration is suitable. As a result of the comparative inspection, if it is determined that the printed matter is abnormal, an abnormality is displayed on the display 0&. Other means, such as rejecting abnormal printed matter or marking it, may also be used. In reality, it is necessary to input auxiliary information, such as changing the inspection standard according to the required quality of printed matter or setting up an inspection area and a non-inspection area in the field of view of the input camera circle, or to input reference signals. Since it is necessary to instruct the start of the inspection, input board 07)
is connected to the CPU (161), and instructions for the work are given from the input board αD.

Next, the paper holding mechanism (I4), which is a feature of the present invention that enables more accurate inspection, will be explained in more detail based on FIG. 4.

FIG. 4 is a front view of an embodiment of the paper holding mechanism in the printed matter inspection apparatus of the present invention. The entire paper holding mechanism is attached to the printing press body using two jigs (109). A pair of air cylinders (108) and a guide shaft (11) are each fixed on the jig (109).
The support base (107) is moved up and down along the guide shaft by the drive of the operating system (OS). As shown in FIG. 6, this mechanism applies contact pressure at all times when the paper presser roller (101) is pressed against the final impression cylinder (8) to prevent the trailing edge of the printing paper from bouncing up. If the gripper claw (51) collides with the paper press roller (101), this mechanism is provided to prevent such a situation.With this mechanism, the gripper claw (5) The paper presser roller (101) passes through the position of the paper presser roller (101) while the printing paper Ill is being pressurized by the final impression cylinder (8) and the blanket cylinder (3).
) waits vertically above the final impression cylinder, and can contact and apply pressure to the printing paper (1) just before the rear end of the printing paper fil comes out of the pressure position and becomes free. becomes. Also, during printing (that is, during the pressurization between the final impression cylinder (8) and blanket cylinder (3)), a paper presser roller (10
Pressure-bonding 1) to the printing paper (]) may cause printing problems (so-called shock eyes), and if the trailing edge of the printing paper 13+ is free, the above-mentioned problem will occur and input will be difficult. Since the input image information from the camera circle becomes unstable, the paper presser roller (f101i) is lowered and pressurized at the timing just before the trailing edge of the printing paper becomes free as described above.

To release the pressure on the paper presser roller (101), after the trailing edge of the printing paper (1) passes under the paper presser roller (101), move the support stand (107) before the gripper claw (5) arrives again. This can be done by raising it.

The timing of crimping and releasing the filter paper press roller (101) by moving the support stand (107) using the air 9nanda (1OS) is determined by inputting the size of the printing paper in advance from the input board αη. Therefore, the solenoid valve for the air cylinder (108) can be controlled by counting the timing pulses TP of the pulse generator (121).With the above, the entire support base (107) can be moved up and down while keeping the timing, and the printing paper (1 ) can be crimped onto and released from the impression cylinder (8).

In addition, the paper presser mechanism α is set so that the crimping position by the paper presser roller (101) is as close to the signal acquisition line of the human-powered camera α as possible within a range that does not interfere with signal acquisition for inspection.
It is desirable to set the position of the attachment of f3.a, so that the printing paper f3. 1 can be crimped onto the impression cylinder (8). Furthermore, four brazikes (111) are fixed below the support base (107), and a drive screw (103) and a guide (104) are provided between each two brazikes (111). The drive screw (105) can be rotated by a motor (105) fixed to the outer placket (111). On the other hand, the drive screw (1 field) and the roller support (10
2) is also fitted in the guide guide (104) with a groove, so by rotating the drive screw (1OS),
The roller support (102) can be moved in parallel along the guide (104). Further, a paper presser roller (101) is rotatably held below the roller support (102), and as a result, the paper presser roller (101) is moved to the final impression cylinder (
8) Parallel movement in the cylindrical surface height direction is possible. This is because ink stains occur when you press the pattern part of the printed material.
As shown in Figure 5, a pattern (12
0), but by using the fact that the margins (121) are on the left and right sides of the printing paper (1), the margins (121) can be printed.
) must be pressurized with the paper presser roller (101), therefore, the paper presser roller (101) must be pressed depending on the size of the printing paper (1).
This is because it becomes necessary to change the position of 01). The position of the paper presser roller (101) is set in advance by the input board (1n).
According to the size of printing paper (1) input from
05).

With this configuration, it is possible to prevent the rear end of the printing paper (1) from jumping up from the final impression cylinder (8), and stable inspection becomes possible. Furthermore, as shown in Fig. 5, when the printing paper (1) is conveyed in the direction of the arrow, it is better to apply tension in the direction of the arrow E with the paper presser roller (101). ) It is highly effective in preventing swelling in the mid-central area. For this purpose, as shown in FIG. 6, the paper presser roller (101) is shaped like a truncated cone and the roller support (102) is moved downward to increase the pressing force to the final impression cylinder (8). (arrow B direction) plus arrow C
It becomes possible to apply a thrust force in this direction. By attaching the paper press rollers (101) shown in FIG. 6 in opposite directions, it is possible to easily generate tension in the direction of arrow E shown in FIG.

The above is an outline of one embodiment of the paper presser mechanism. Of course, the contact pressure of the paper presser roller (101) and the air cylinder (1a
It would be more effective to provide an adjustment screw or stopper as a mechanism for adjusting the amount of movement by S), and there would be no problem with other drive systems or adjustment mechanisms as long as they have a structure that shows the same effect. do not have.

As described above, the print inspection device of the present invention has the paper holding mechanism, thereby enabling in-line print inspection on a sheet-fed printing press, which has been extremely difficult in the past. Inspection can be stabilized by preventing the trailing edge of the printing paper from bouncing up.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the transportation state of printing paper in a sheet-fed printing press, FIG. 2 is an explanatory diagram of a method for stabilizing the transportation of printing paper by air blowing, and FIG. 6 is an explanatory diagram showing the conveyance state of printing paper in a sheet-fed printing press. FIG. 4 is an explanatory diagram showing one embodiment of the inspection device, FIG. 4 is an explanatory diagram of one embodiment of the paper holding mechanism of the printed matter inspection device of the present invention, and FIG. 5 is an explanatory diagram showing the state of printing paper. 6 is an explanatory diagram of a truncated conical paper presser roller. 1...Printing paper 101...Paper presser roller 6.
... Rubber cylinder 103 ... Conveyance screw 5 ... Biting claw 105 ... Motor 8 ... Final impression cylinder 108 ... Air cylinder 11 ... Input camera 14 ... Paper holding mechanism 16 ... ...CPU patent application Toppan Printing Co., Ltd. Representative Kazuo Suzuki (1 other person) Figure 2

Claims (1)

[Scope of Claims] 1) It is installed in a sheet-fed printing machine, captures image information of the pattern of the printed material pixel by pixel, and compares the detected image signal of each pixel with the reference signal of the corresponding pixel to detect the image of the printed material. In a printed matter inspection device for inspecting abnormalities, a detection system including an input camera for capturing image information of a pattern on a printed material detects image information of a pattern on a printed material on an impression cylinder immediately after printing is completed in the final printing unit of a printing press. A printed matter inspection device is provided with a paper holding mechanism that is installed at a position where it can be taken in and presses the printed matter onto an impression cylinder between a printing position of a final printing unit and a position where image information of a pattern of the printed matter is taken in. 2) The paper press mechanism includes a support base, a pair of paper press rollers that can be moved in parallel on the support base, an adjusting means for moving the paper press rollers to a desired position, and an impression cylinder that moves the entire support base. 2. The printed matter inspection apparatus according to claim 1, further comprising: a drive means for moving the print material in a direction toward and away from the surface; and a control means for controlling the adjustment means and the drive means. 3) The printed matter inspection apparatus according to claim 2, wherein the paper pressing roller has a truncated conical shape.