JPH0411793Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a printed matter inspection device for detecting abnormalities in the printed matter by inline comparing the state of the printed matter being printed with a standard state in a printing machine.

[Technical background of the invention and its problems]

Conventionally, the mainstream method for inspecting printed matter has been offline and relying on human vision. This stems from the fact that each piece of printed matter has a different pattern, and because inspection items for printed matter have been thought to involve subtle differences that require reliance on human vision. 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. I was disappointed. However, these methods were not systems that could be called inspection machines in that they relied on human vision for inspection. Attempts have also been made to print a color patch at the same time as the pattern on the printed matter and inspect the color patch, thereby allowing the inspection of the printed matter to be performed on behalf of the user. However, with this method, if printing defects (oil drips, stains, etc.) occur in the pattern area, they will be overlooked, and the inspection machine cannot be said to perform its function satisfactorily.

On the other hand, recently, a system has been proposed in which printed matter is inspected in-line using a line sensor, as seen in the "Printed Material Inspection Apparatus" disclosed in Japanese Patent Application No. 57-220515.

Specifically, as shown in FIG. 2, a strip of printing paper 23 fed from a roll of paper 22 is printed in four colors (black, indigo, red, and yellow) on both sides in the printing section 21. After each printing is done,
The paper is transported to a dryer and a folding machine section (not shown). The print inspection device inspects the printing condition after printing in four colors on the front and back sides, and while timing the sampling with a rotary encoder 25 installed in the printing section, prints pattern information in a direction perpendicular to the flow direction of the print. of the detection section 24 extending to
A line sensor such as a CCD or MOS is used to scan the line sensor as a main scan, and the flow of the printed material is transferred to a processing circuit 26 pixel by pixel as a sub-scan to determine whether the printed material is normal or abnormal. As a result,
If it is determined that the printing condition is abnormal, it is possible to take measures such as alarms, markings, rejects, etc.

By using this system, the pattern itself of printed matter can be automatically inspected in-line, so the above-mentioned drawbacks are eliminated, and excellent effects can be expected as an inspection machine.

However, this system is not without its problems, and since it is better to leave the final quality of printed matter to human judgment, it cannot handle cases where you want to ignore small defects that the inspection equipment has judged as defective. be. In order to solve this problem, a method for erasing defective indications on a display has been proposed in Japanese Patent Application No. 134813/1983 filed by the present applicant, entitled "Print Inspection Apparatus." The present invention is proposed to solve a similar problem.

[Purpose of invention]

The present invention solves the above-mentioned problems and provides a print inspection device that has a simple configuration, provides flexibility in determining printing defects, and enables more efficient inspection.

[Summary of the idea]

The present invention was made to achieve the above object, and it captures the pattern of a printed matter pixel by pixel, converts the detected pattern information of each pixel into a digital signal, and converts the detected pattern information of each pixel into a digital signal, and then converts the pattern information of the detected pixel into a digital signal. This is a device that performs comparison calculations with reference information for each item and determines whether the comparison result is within an allowable range to inspect abnormalities that occur in printed matter, and displays abnormalities that occur in printed matter on a display. At the same time, the display is performed by referring to the states of the two masks, and
Of the two masks mentioned above, one mask is created during the initial settings after the start of the test and remains unchanged during the test, and the other mask is created after the start of the test when a printing failure occurs, and can be cleared at any time during the test. This is a printed matter inspection device characterized by:

[Details of the idea]

The present invention will be described in detail below with reference to embodiments shown in the drawings.

FIG. 1 is a block diagram showing the configuration of a printed matter inspection apparatus according to the present invention.

The printed matter inspection device attached to the printing press controls the sampling timing with a timing control circuit 3 based on timing pulses from a rotary encoder 2 attached to the impression cylinder, plate cylinder, etc. The entire image of the printed matter is input as image information IS divided into pixels from a line sensor or the like.

Next, after the pattern information IS is digitized by the A/D converter 4, for example, the operator determines that the printed matter is normal and presses the standard image import button from the operation panel 13, thereby determining the normal pattern of the printed matter. Information is stored in reference memory 6.

Thereafter, when the inspection is started, the information in the reference memory 6 is read out according to a signal from the memory control circuit 5 controlled by the CPU 11, and is used as reference information for the pixel corresponding to the pixel to be inspected. . As a result, during the test, the detection unit 4
The picture information for each pixel inputted from the pixel is digitized, and then paired with the reference information of the corresponding pixel and transferred to the discrimination circuit 9, where it is determined whether or not an abnormality has occurred. Here, the discrimination method is to differentiate the two, and when the difference value exceeds the allowable range, it is determined that there is a printing abnormality. It is possible to apply any discrimination method such as the discrimination method detailed in "Printed Material Inspection Method" by No.

On the other hand, as described in the patent application No. 134813/1989 filed by the present applicant for a "printed matter inspection device," a mask memory B8 that can be freely rewritten during detection is provided to prevent printing failures that the operator considers unnecessary to display. In this case, by pressing the display unnecessary key on the operation panel 13, a flag is set at the same address as the pixel where the printing failure has occurred, indicating that the display is unnecessary. In addition, a mask memory A7 is provided, and at the start of the inspection, instructions for areas not required to be inspected and edge extraction are made, and flags are set in the mask memory A7 to bits indicating pixels not required to be inspected.

Such mask memory A7 and mask memory B8 are connected to the AND circuit 10 together with the output signal of the discrimination circuit 9, and the mask signals of the mask memory A7 and mask memory B8 having the same address as the pixel judged to be abnormal by the discrimination circuit 9 are connected to the AND circuit 10. AND circuit 1
It is inverted to 0 and input. The AND circuit 10 determines whether an abnormality has been determined and the mask memory A,
A true abnormal signal is detected when the condition is satisfied by calculating the logical product of whether the bit of B is flagged or not.
Output ES to CPU11. As a result, CPu11
The occurrence of printing abnormality can be displayed on the display 12. Also, other possible measures when an abnormality occurs include marking, rejecting, etc.

[Effects of the invention] As described above, according to the invention, it is possible to display the occurrence of an abnormality only in necessary parts in a printed matter inspection device, and the operation by the operator is simplified. Has excellent effects.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a block diagram showing the configuration of the print inspection device of the present invention, and FIG. 2 is an explanation showing the print inspection device installed in a printing press. It is a diagram. 1...Detection unit, 2...Rotary encoder,
6...Reference memory, 7...Mask memory A,
8...Mask memory B, 10...AND circuit,
11...CPU.

Claims (1)

[Scope of utility model registration request] The pattern of the printed matter is captured pixel by pixel, the detected pattern information for each pixel is converted into a digital signal, and compared with pre-stored reference information for each pixel, and the comparison result is within an acceptable range. An inspection device that inspects abnormalities that occur in printed matter by determining the presence or absence of abnormalities in printed matter has two mask memories having bits indicating information regarding display of inspection results at addresses corresponding to the pixels to be inspected. , one of the mask memories is writable before the inspection, and the other mask memory is rewritable during the inspection;
A printed matter inspection device characterized in that an abnormality in a printed matter is determined by referring to the contents of two mask memories.