Printing – Multicolor – Processes
Patent
1989-09-15
1991-10-15
Burr, Edgar S.
Printing
Multicolor
Processes
101181, B41M 114
Patent
active
050564307
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention is directed generally to a method of positioning printing plate cylinders in a multi-color rotary printing machine. More particularly, the present invention is directed to a method for positioning plate cylinders in a multicolor rotary printing machine by using register marks. Most specifically, the present invention is directed to a method for positioning plate cylinders in a multi-color rotary printing machine using register marks on each plate cylinder with these register marks being arranged to form regular geometric figures as register marks prints on the print carrier. These regular geometric figures may be concentric circles or squares and facilitate the measurement of the distances between adjacent register marks so that these distances may be analyzed by suitable electric image detecting devices. Once the positions of the register marks prints have been measured and analyzed, the printing plates can be adjusted, if necessary, to correct register errors.
DESCRIPTION OF THE PRIOR ART
It has become generally known in the art to utilize various television cameras and associated video devices to evaluate printed products. The publication "Technische Vortrage 1971" or Technical Speeches 1971, published by the Deutsche Forschungsgesellschaft fur Druck-und Reproductionstechnik e.v., or the German Research Company for Printing and Reproduction Technology provided an essay entitled "Application of TV-Picture Evaluation for Measuring Tasks of the Printing Technology". This essay discussed the use of a video signal from a TV camera to evaluate printed products. It is further generally known in the art to optically enlarge various video pictures so that a picture element to be evaluated will be cut by a sufficient number of TV-lines.
In the German published unexamined patent application No. 31 38 689 there is disclosed a device for the detection of picture copies by using a video camera as the detection device. In this application, the camera is a vidicon or so-called CCD-camera and may be equipped with a zoom objective lens. In another German published unexamined patent application No. 24 55 973 there is described an optical character searching device in which the video signal may be digitized.
In PCT Application No. WO 86/05141 there is disclosed a process and a device for the execution of the process which is useable with a multi-color rotary printing machine to position the various plate cylinders of the printing machine with respect to each other. This is accomplished by utilizing deviations of one register mark with respect to each other. This is accomplished by using a video camera to record a group of marks printed on the print carrier and to form an image of this group of marks. This image is then converted into a numerical image which may be compared with an "analysis window". The "analysis window" consists of a reference point to which is associated a mark on the printing carrier.
A disadvantage of the above-discussed process is that the ink register marks are provided as points with a diameter of approximately 1 mm with these points being arranged as corner points of an imaginary square having an edge length of approximately 10 mm. This type of register points are difficult to detect electronically. Defects on the printing carrier itself in the area adjacent or within the square of register marks could erroneously be analyzed as register point by the electronic system. Additionally, for point-shaped register marks, a leading, additional, bar-shaped trigger register mark is required. Furthermore, the position of each point to each other point must be calculated in both the X- and Y- directions. If the electronic system fails, it is quite difficult for the printer to visually recognize the register deviation of the marks as they can be separated from each other by a distance of up to 10 mm and more. Due to the large distance between the color register marks, it is impossible to measure the distances between the marks by using a measuring microscope. As
REFERENCES:
patent: 3015266 (1962-01-01), Anderson et al.
patent: 4273045 (1981-01-01), Crowley
patent: 4534288 (1985-08-01), Brouman
patent: 4932320 (1990-06-01), Brunetti et al.
"Application of TV-picture for measuring tasks of the printing technology"--Technical Speeches 1971--publication by the German Research Company for Printing and Reproduction Technology.
Bayerlein Friedrich K.
Leuerer Dietrich R. K.
Burr Edgar S.
Koening & Bauer Aktingesellschaft
Yan Ren
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