JPS62220843A - Inspection device for printed matter - Google Patents

Abstract

PURPOSE:To eliminate the need for an intricate mounting mechanism and fixing mechanism and to eliminate the influence of the variance in the sensitivity of a photodetecting system by inspecting the designs of the same pattern by using one unit of self-scanning type photoelectric detector. CONSTITUTION:Reflected light 102 which is irradiated from a light projector 1 and is reflected by printed matter 2 is received by the self-scanning type photoelectricd detector 3 and the digital pattern signal corresponding to the respective designs of the printed matter 2 from an analog-to-digital converter 4 is fed to a reference pattern memory 5 and a comparative discrimination circuit 10. The reference pattern memory 5 stores the signal into prescribed addresses by each of the designs and at the same time said memory outputs the digital pattern signal corresponding to the already stored design before the provious design and delivers the same to the circuit 10. The circuit 10 compares and discriminates the signal from the analog-to-digital converter 4 and the signal corresponding to the design before the previous design from the memory 5 by the timing signal from a timing control circuit 8 and outputs a defectiveness and non-defectiveness discrimination signal E.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an inspection device for printed matter, and particularly to an inspection device for inspecting printed matter, and particularly for inspecting a plurality of pictures of the same pattern printed in a straight line, for example, printed on the same paper. The present invention relates to a printed matter inspection device that detects and determines dirt on the printed surface of securities, stamps, etc.

[Conventional technology]

Conventionally, in this type of printed matter testing equipment, a plurality of detectors are provided in the transport direction of a plurality of printed matter having the same pattern, and each of these detectors scans the same portion of the adjacent picture. Then, the difference between the detection signals obtained by each detector is taken, and the quality of the printed matter is determined based on the magnitude of the difference. As an example, for example,
An example is given by No. 9-108553.

(Problem to be Solved by the Invention) The conventional printed matter inspection apparatus described above uses a plurality of detectors to compare and judge the same scanning portion of a plurality of adjacent images of the same pattern. The first prerequisite for maintaining inspection accuracy is that the receiving beams of each of the plurality of detectors always correspond in a one-to-one relationship to the same part of the pattern of the first pattern adjacent to each other. This has the disadvantage that a complex adjustment and fixing mechanism is required for setting up the plurality of detectors.

In connection with the optical system or lighting of the detector, there may be variations in the sensitivity of the light receiving element for photoelectric conversion detection, shading, uneven light emission, etc., and the photoelectric conversion detection signals corresponding to the same part of the same pattern may Since there is an error signal between both, if the difference is within the level of the error signal,
The disadvantage is that it is not possible to judge whether the printed matter is good or bad.

[Means for Solving the Problems] The printed matter inspection apparatus of the present invention conveys in a predetermined conveying direction a printed matter in which a plurality of pictures of the same pattern are printed on the same sheet of paper arranged in a straight line. In the mark 11 object inspection device that determines the quality of the pattern through a self-scanning photoelectric conversion detection means, photoelectric conversion detection is sequentially outputted in correspondence with the pattern by the self-scanning photoelectric conversion detection means. A digital pattern signal (A
a reference pattern storage means for sequentially storing the digital pattern signal (A) and reading out and outputting the digital pattern signal (B) corresponding to the pattern immediately before the previously stored pattern; The digital
Comparing and determining means for comparing and comparing the pattern signal (B) and determining the quality of the printed matter.

〔Example〕

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention. As shown in FIG. 1, this embodiment includes a light projector 1, a self-scanning photoelectric conversion detector 3, and an A-D converter 4 corresponding to the printed matter 2 conveyed along the conveyance direction 101.
, a reference pattern memory 5 , a photoelectric detector drive control circuit 6 , a rotary encoder 7 , a timing control circuit 8 , a memory address control circuit 9 , and a comparison judgment circuit 1
It is equipped with 0 and .

In FIG. 1, the printed matter 2 is transported along the conveyance direction 101.
It is being transported at a predetermined transport speed.

Reflected light 102 emitted from the projector 1 and reflected by the printed matter is received by the self-scanning photoelectric conversion detector 3, converted into an electrical signal, and sent to the AD converter 4 as a photoelectric conversion detection signal. In this embodiment, the automatic scanning photoelectric conversion detector 3 is a CCD (Charge Coupon).
The light receiving beam of the self-scanning photoelectric conversion detector 3 is controlled by the drive pulse signal φ1 and the scan switching signal φd sent by the photoelectric detector drive control circuit 6. electrically scanned. The scanning of the light receiving beam is performed in a direction substantially perpendicular to the conveying direction 101 of the printed matter 2, and photoelectric conversion detection signals corresponding to the same pattern of the printed matter 2 are sequentially acquired along the conveying direction 101. .

The photoelectric conversion detection signal input to the A-D converter 4 is
The reference pattern is A-D converted via the timing signal sent from the timing control circuit 8 and sent to the reference pattern memory 5 and the comparison/judgment circuit 10 as a digital pattern signal corresponding to each pattern of the printed matter 2.
The memory 5 is controlled by an address designation signal input from a memory address control circuit 9, and stores the digital pattern signal input from the A-D converter 4 at a predetermined address for each picture. , has a function of outputting a digital pattern signal corresponding to the previous picture that has already been stored and sending it to the comparison/judgment circuit 10, where the digital pattern signal is input from the timing control circuit 8. the digital pattern signal directly sent from the A-D converter 4 via a predetermined timing signal; and the digital pattern signal corresponding to the previous picture read out from the reference pattern memory 5. are compared and determined, and a quality determination signal E for the digital pattern signal directly input from the AD converter 4 is output.

The above reference pattern memory 5 and comparison judgment circuit 10
In parallel to the operating process in, on the one hand, the printed matter 2
The conveyance position of each picture in is detected by a rotary encoder 7 that is linked to the rotational movement of the rotation mechanism that conveys the printed matter 2, and sent to a memory address control circuit as a conveyance position signal corresponding to each picture via a timing control circuit 8. 9
The drive pulse signal is also controlled by a predetermined timing signal sent from the timing control circuit 8, generated in the drive control circuit 6, and sent to the self-scanning photoelectric detector 3. Similarly, it is input to the memory address control circuit 9. In the memory address control circuit 9, a memory address corresponding to each scanning position in the pattern of the printed matter 2 is set in response to the input of the transport position signal and the drive pulse signal, and the address designation signal is generated and the reference pattern is - Sent to memory 5. Note that if the conveyance speed of the printed matter 2 changes, the correspondence between the scanning position and the position on the pattern of the printed matter 2 will collapse, so the transfer lock of the self-scanning photoelectric detector 3 will be disabled.
The timing is controlled by the timing control circuit 8 so that the blanking period is made variable by the output of the rotary encoder 7, and the digital value corresponding to the same part of the picture is always input to the same memory address. be exposed.

Through the operations of the above-mentioned parts, a plurality of pictures of the same pattern arranged in the direction along the conveyance direction 101 in the printed matter 2 are sequentially detected as photoelectric conversion detection signals back and forth, and a difference between adjacent pictures is detected as a photoelectric conversion detection signal. The photoelectric conversion detection signals are compared and verified, and the quality of the printed matter is determined based on the magnitude of the difference.

〔Effect of the invention〕

As explained above, the present invention uses one self-scanning photodetector to inspect the same pattern of images printed in a straight line on the same paper surface, thereby detecting multiple self-scanning images. To eliminate the need for mechanically complex mounting adjustment and fixing mechanisms that occur when using a scanning photoelectric detector, and to completely eliminate the effects of sensitivity variations, shading, and uneven light projection in the light receiving system. It has the effect of being able to. Furthermore, by automatically making the blanking time of the transfer block of the self-scanning photoelectric detector variable, it can be expected that there will be no need for adjustment for scanning the same portion of the same pattern.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, 1... Light emitter, 2... Printed matter, 3... Self-scanning photoelectric detector, 4...
...A-D converter, 5...Reference pattern memory, 6...Photoelectric detector drive control circuit, 7...
... Rotary encoder, 8 ... Timing control circuit, 9 ... Memory address control circuit, 10 ... Comparison judgment circuit.

Claims (1)

[Claims] A printed matter in which a plurality of pictures of the same pattern are arranged in a straight line on the same paper is transported in a predetermined transport direction, and the quality of the pictures is determined via a self-scanning photoelectric conversion detection means. In the printed matter inspection apparatus, the self-scanning photoelectric conversion detection means sequentially stores digital pattern signals (A) obtained through photoelectric conversion detection signals sequentially output in correspondence with the patterns, and a reference pattern storage means for reading out and outputting a digital pattern signal (B) corresponding to the picture immediately before the picture being displayed;
) and the digital pattern signal (B) to determine the quality of the printed matter.