JPH01263050A - Examining device for printed matter - Google Patents

Abstract

PURPOSE:To eliminate the adverse influence of a dispersion in sensitivity, irregularities in light projection, and others ans to detect even a little amount of stain, by scanning images of the same pattern printed and arranged in a feed direction and in a serial direction on the same paper surface with use of one self-scanning photoelectric detector. CONSTITUTION:A printed matter 2 is fed to be irradiated by a projector 1. The reflected light 102 is accepted and converted by a self-scanning photoelectric transfer detector 3 to be transmitted to an A/D converter 4 as a photoelectric transfer detection signal, thereafter being transmitted to a reference pattern memory 5 and a differential amplification circuit 10 as a digital pattern signal. The detector 3 is controlled by a timing control circuit 8 so as to start scanning at the time of the shift of the printing matter 2 by a rotary encoder 7. In a memory address control circuit 9, the feed position information is converted to a memory address and is also generated for the scanning position information of the self-scanning detector 3. In a difference output integrating circuit 11 for detecting stains existing on the printed matter 2, the integrating output of a difference signal is obtained, and a judgement circuit 12 outputs an YES/NO quality judgement signal E when either the output from the differential amplification circuit 10 or from the differential output integrating circuit 11 is is over a fixed value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inspection device for printed matter, and particularly for inspecting printed matter in which the same picture is printed in series in the same direction as the conveyance direction on the same paper surface, for example, on the same paper surface. The present invention relates to a printed matter inspection device that detects and determines dirt on the printed surface of securities or stamp sheets on which the same pattern is printed.

[Conventional technology]

Conventionally, this type of printed matter inspection equipment focuses on the fact that multiple identical patterns are printed parallel to the conveying direction, and installs multiple detectors in a direction perpendicular to the conveying direction of the printed matter to detect these. The same parts of adjacent patterns were scanned by the detectors, the difference between the detection signals obtained by each detector was determined, and the quality of the printed matter was judged based on the magnitude of the difference. For example, Japanese Patent Application No. 41-56888
An example can be given by number.

[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, so that the received light beam of each of the plurality of detectors is A prerequisite for maintaining inspection accuracy is that there is always one-to-one correspondence between the same portions of the same patterns that are adjacent to each other. For this reason, the setting of the plurality of detectors not only has the disadvantage of requiring complicated adjustment and fixing mechanisms, but also has the disadvantage of requiring a complex adjustment and fixing mechanism, as well as a problem with the optical system or illumination system of the detectors. There are variations in element sensitivity, shading, uneven light projection, etc., and error signals also exist in the photoelectric conversion detection signals corresponding to the same part of the picture of the same pattern. If only the difference is obtained, there is a drawback that it is impossible to judge whether the printed matter is good or bad.

[Means to solve the problem]

The printed matter inspection device of the present invention uses a self-scanning photoelectric conversion detection means while conveying a plurality of printed matter printed in the same paper plane in a predetermined conveying direction in a manner that is arranged in series with the picture direction of a plurality of identical patterns. In the printed matter inspection apparatus for determining the quality of the pattern through the self-scanning photoelectric conversion detection means, the photoelectric conversion detection signal sequentially outputted corresponding to the pattern is digitally converted via the A/D conversion circuit. means for converting into a pattern signal, means for sequentially storing the results as a reference pattern, timing control means for a self-scanning photoelectric detector for scanning the same location in the conveying direction of the pattern, and self-scanning photoelectric detector. means for always storing the same part of the pattern in the same part of the reference pattern memory based on the scanning position information obtained from the conversion detector and the conveyance direction position information obtained by the timing control; It has a comparative judgment means for determining whether the printed matter is good or bad based on the difference between the digital pattern signal obtained during scanning and the difference, and a means for integrating the difference signal for detecting light stains. .

〔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 conversion detector drive control circuit 6 , a rotary encoder 7 , a timing control circuit 8 , a memory address control circuit 9 , a differential amplifier circuit 10 , and a differential output integration circuit 11 . , and a determination circuit 12.

In FIG. 1, the printed matter 2 is transported along the conveyance direction 101.
transported. Reflected light 1'02 emitted from the projector 1 and reflected by the printed matter 2 is received by the self-scanning photoelectric conversion detector 3, converted into an electrical signal, and sent to the A/D converter 4 as a photoelectric conversion detection signal. . In this embodiment, the self-scanning photoelectric conversion detector 3 is constructed using a COD, and the photoelectric conversion detector drive control circuit 6
It is controlled by the COD drive pulse signal sent by. The photoelectric conversion detector 3 scans in the transport direction 1 of the printed matter 2.
01, and photoelectric conversion detection signals corresponding to the patterns of the printed matter 2 are sequentially output along the conveyance direction 101.

The photoelectric conversion detection signal is converted into an A/D converter 4 by an A/D converter 4.
The signal is converted and sent to the reference pattern memory 5 and the differential amplifier circuit 10 as digital pattern signals corresponding to each pattern of the printed matter 2.

The above-mentioned storage in the reference pattern memory 5 is controlled by the rotary encoder 7 that detects the conveyance position of the printed material 2 based on the picture position in the conveyance direction, that is, the 5 conveyance direction position information, and at the same time, the reference pattern memory 5 is
The rotary encoder 7 performs self-scanning photoelectric conversion when the printed matter 2 moves a certain distance, so that the digital pattern information stored in The timing control circuit 8 controls the scanning of the self-scanning photoelectric conversion detector 3 so as to start scanning the detector 3, and the memory address control circuit 9 starts the self-scanning at the same time that the conveyance position information is converted into a memory address. The scanning position information of the mold detector 3 is also input to the memory address control circuit to generate a memory address.

The reference pattern memory 5 is controlled by an address designation signal inputted from a memory address control circuit 9, and is
The digital pattern signal inputted from the D converter 4 is stored in a predetermined address for each picture, and the digital pattern signal of the immediately previous picture already stored is outputted and sent to the differential amplifier circuit IO. The difference signal between the digital pattern output from the A/D converter and the digital pattern of the immediately previous picture is output.

Note that stains that exist on the printed matter 2 include, for example, relatively light but large stains such as oil stains, and vertical stains such as roller scratches.
A difference output integration circuit 11 that integrates the difference signal for each predetermined area in order to detect light stains on the surface of the sensor body obtains an integrated output of the difference signal. The determination circuit 12 outputs a quality determination signal E when the output of either the differential amplifier circuit 10 or the differential output integration circuit 11 exceeds a certain value.

〔Effect of the invention〕

As explained above, the present invention uses a single self-scanning photoelectric detector to scan pictures of the same pattern printed on the same sheet of paper in a direction parallel to the conveying direction. Generated by using a scanning photoelectric detector. Mechanically complex mounting adjustment and fixing mechanisms are no longer required, and variations in sensitivity in the light receiving system are eliminated.
The effects of shading and uneven light projection can be completely eliminated, and even light dirt can be detected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, 1... Floodlight, 2... Printed matter, 3... Self-scanning photoelectric detector, 4... River/A/D converter, 5... ...Reference pattern memory,
6...Photoelectric detector drive circuit, 7...Rotary encoder, 8...Timing control circuit, 9...Memory address control circuit, 10...
...Differential amplifier 1i circuit, 11... differential integration circuit, 1
2...Judgment circuit. Agent Patent Attorney Oto Uchihara Figure 1

Claims (1)

[Claims] A printed matter in which multiple pictures of the same pattern are arranged in the same direction as the transport direction on the same paper is sequentially scanned by a self-scanning photoelectric detector, and the data read for each picture is stored as a reference pattern. means for creating information stored in the reference pattern memory based on scanning position information by a self-scanning photoelectric detector and conveyance position information of the printed material; It is equipped with means for controlling based on position information, means for calculating the difference between other patterns on the same page, and determining whether the printed material is good or bad based on the magnitude of the difference signal, and integrating the difference signal to detect light stains. A printed matter inspection device equipped with a means for inspecting printed matter.