NZ210951A - Rotary press for simultaneous multicolour printing of both sides of a paper web or sheet - Google Patents

Description

2109 5' O Priority Date(s): Complete Specification Filed: Class: .fch-J. f.'JM;- fo./PS.yU-. f*5'DEC'f9'| Publication Date: P.O. Journal, No: ... /•£?« 2 1095 1 €> Patents Form No. 5 NEW ZEALAND PATENTS ACT 19 53 COMPLETE SPECIFICATION "ROTARY PRESS FOR THE SIMULTANEOUS MULTICOLOR PRINTING OF BOTH SIDES OF A WEB OR SHEET" -17 WE D3 LA RUE GIORI S.A. of 4 rue de la Paix 100 3 Lausanne Switzerland, a Swiss Company, hereby declare the invention, for which I/we pray that a patent may be granted to me/us, and the method by which it is to be performed, to be particularly described in and by the following statement 210951 FIFI0 OF INVENTION Tho invention relates to a rotary pros* for tho (imulttnsoug multicolor printing of both sides of a web or sheet.

PRIOR ART A machine is already known through the published ;!rit;ish Speci f i cntic>n N'o. ."!Q,J4 71(5 which porforma on one aide of the paper the printing of an image with juxtipoied color*. Thia image is printed by means of a single typographic printing plate representing the complete design to be printed and mounted on a plate cylinder. This typographic plate is inked by a collecting device consisting of a blanket cylinder inked in turn by a plurality of selective color inking cylinders of which the number corresponds to the image to be printed. Each selective inking cylinder comprises relief cut areas representing the image portions to be colored in a predetermined color transferred thereto by its inherent inking device. This machine is intended notably for printing the safety background of bank notes.

With this method, currently referred to as the "Orlof" or color collecting printing method, a multicolor image is obtained which ensures a perfect registration between the different colors of the image design, a result that cannot be obtained with any other printing method. Since the selective color inking cylinders are in contact with a resilient surface of the collecting cylinder, they can be manufactured from hard material so that areas having a very fine relief, and therefore vary fine colored portions, for example in the form of lines or points, can be obtained.

On the other hand, indirect or offset typographic printing with superposed colors and design is also knows which, likewise,is frequently utilized for printingsafety A*:'-* . - 2 - ,fv P 29SET1 ■ . V \*>r' ■ " 21095 1 o backgrounds. According to this method, the complete design conaiiti of partial daiignt in different colors carried by offset printing plates mounted on plate cylinders to permit the superposition of designs and colors registering with one another on a blanket cylinder against which the paper to be printed is pressed. The number of offset printing plates and consequently of plate cylinders corresponds to the number of different colors and designs constituting the multicolor image.

Machines of this type sre also known for the simultaneous printing on both sides. wherein the paper passes between two blanket cylinders receiving each a multicolor image from the corresponding offset plate cylinders.

In the present state of the art machines have been developed which exploit separately one or the other of the above-described methods.

SUMMARY OF THE INVENTION It is the object of this invention to provide a 20 aingle and same machine combining in a simultaneous recto and verso printing the two above-described methods and referred to hereinafter as the "Orlof* method and the offset method.

To achieve this purpose, the invention is characterized by a machine as disclosed in claim 1.

The advantage of this machine consists in that it permits of exploiting simultaneously two totally different methods for printing in a single pass an offset image on one side and an "Orlof* image on the other aide. thus 30 offering the user for the first time the possibility of printing notably safety backgrounds on both sides of a bank note through two different methods; this increases the safety against forgery and in addition makes printing operations more economical because the user is not compel- •,2K--. l*d to resort to two separate machines.

Advantageous forms of embodiment of the inventions •re described in the depending claims.

The invention will be described by way of non-limiting example through one form of embodiment and a modified version with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates diagrammatically a printing machine according to the invention.

Figure 2 illustrates diagrammatically. in fragmentary view, an extension of this machine completed by another wet offset printing unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The machine illustrated relates to a sheet printing machine and comprises an input device 1 for the paper in sheet form, which is provided with a stop drum 2. two transfer drums 3 provided with grippers. end dedusting and static electricity eliminators 4.5 installed on both sides of the paper 1. The sheets are transferred to a blanket cylinder 12 provided with grippers and pressed against another blanket cylinder 13 of same diameter. The sheets pass between blanket cylinders 12 and 13 and are printed simultaneously on both sides. The cylinders rotate in the direction shown by the arrows. After printing, the sheets are conveyed by a chain gripper system 21 and delivered to output piles or. if necessary. to another machine for completing the printing. The main motor of the machine is designated by reference numeral 22.

The blanket cylinder 12 cooperates according to Figure 1 with four offset plat* cylinders 6 of which three. in the example discussed herein, are each provided with a dry offset printing plate *ach ink*d by an inking unit with doubl* ink duct; the fourth offset plat* cylinder 11 carries a wet offset printing plat* ink*d by 1 o o an inking unit 9 with single ink duct provided with a dampening device 10. All thasa alamanti 7 to 11 ara installed on a movable offset inking carriage S.

The dry offset printing plates ara typographic plates known per se and the wet offset printing plate is an intaglio plate also known per se. These four offset plates represent partial designs which are inked in different colors and their number corresponds to the number of colors and designs of the first image to be printed on one side of paper 1. This image is notably a safety background in the case of fiduciary documents. notably bank notes .

These partial designs in different colors are combined on the blanket cylinder 12 acting as an offset blanket cylinder, therefore as a collecting cylinder for the partial designs constituting the multicolor image. This image is transferred to one side of the paper, in the example concerned on the back side, where a three-color dry offset printing is obtained and completed by a monochrome wet offset printing.

In the case of fiduciary documents one may also use the three dry offset plate cylinders S for creating a three-color background. whereas the wet offset plate cylinder 11 represents a main design.

Of course for the offset printing method all the plate cylinders mounted on the movable carriage £. therefore in the example concerned all the four plate cylinders. can also be provided with dry offset plates.

On the other side of the machine the elements necessary for printing an "Orlof" image are disposed. These elements comprise a blanket cylinder 17 having the same diameter as blanket cylindera 12 and 13. This blanket cylinder 17 cooperates in the example illustrated with four selective color inking cylinders 16 having relief 2 109 5 1 ar*as cut according to tha contours of tha area* to ba printad in tha respective color, they ar* *ach ink*d in this color by maans of an inking device 15 with double ink duct. Thase elements 15,16 are installed on an "Orlof" movable inking carriage 14. Thase selective cylinders 16 are made preferably of hard material not prone to undergo any distortion even if the relief is very fine, thus permitting of obtaining a safety background consisting of very fine color areas. The areas of the four colors are transferred to the blanket cylinder 17 operating as a collecting cylinder on which they are combined and by which they are transferred to a plate cylinder 20 carrying a typographic printing plate contacting said collecting cylinder and also blanket cylinder 13. This typographic plate represents the complete design of the second image to be printed in four colors on the other side of the paper. The complete image inked in the different colors is transferred in turn to blanket cylinder 13 for applying the printing of the complete image, notably a safety background, to the front side of the paper, of which the back side receives simultsneously the offset image. During the simultaneous printing the two cylinders 12 and 13 act mutually as counter-pressure cylinders.

The machine further comprises a first image transfer cylinder 16 and a second image transfer cylinder 19 both adapted to transfer the same image from the colored areas of blanket cylinder 17 in perfect registration to the typographic plate cylinder 20, thus permitting of reinforcing the inking of the typographic plate in th* «Sesir*d colors and therefor* of better covering these areas with the d*sir*d ink. In fact. considering the direction of rotation of blanket cylinder 17, one fraction of the ink is transferred by cylinders 18 and 19 to th* typographic plate cylinder 20 whereas th* remaining 'V I fraction of th* ink ia tr«nif*rr*d in p*rf*ct registration directly to this cylinder 20. The arrangement of the cylinders involved for obtaining this double inking is known IDE.A-3,109.I6M, the second inking being shifted by the length of the periphery of the typographic plate cylinder 20 or. in the example considered herein, by one-third of the periphery of blanket cylinder 17 because the latter has a diameter three times greater than the diameter of cylinder 20 and carries three blankets.

To meet this registration requirement, th* arrangement of cylinders 17.10,19 and 20 is such that the sum of the arc lengths measured on the peripheries of cylinders 16.19 and 20 between the respective points of contact - as seen in the direction of rotation of these cylinders -must be equal to the arc length measured on the periphery of cylinder 17 between the points of contact of this cylinder with cylinders 16 and 20. plus 1/3rd of the periphery of this cylinder 17.

If the design carried by the typographic plate for the "Orlof" printing consists only of lines, therefore of very narrow inked areas, the image transfer cylinders 16 and 19 may be dispensed with and merely a aingle inking of the "Orlof" typographic plate may be accomplished.

In the example illustrated the ratio of the diameters of cylinders 8.11.16.16,19 and 20. on the one hand, to the diameters of cylinders 12,13 and 17, on the other hand, is 1:3; therefore. since the periphery of cylinders 12,13 and 17 corresponds to three papers sheets, these cylinders carry each three blanket.

In the example of Figure 2 th* printing according to the "Orlof" method is completed by a wet offset printing also performed when the paper passes between blanket cylinders 12 and 13. which also s*rv*s notably for printing a monochrome main deaign of currency paper. The wet C\ 2 1095 1 offset unit comprises an intaglio plate cylinder 23 provided with an inking unit 24 and a dampening device 25. both known per se. this intaglio plate cylinder 23 cooperating with blanket cylinder 13 that transfers the image to the paper. Therefore, in this case there is obtained in a single pass on the front side a complete printing for example the four-color safety background by printing according to the "Orlof" method and the monochrome main design by printing according to the wet offset method, 1Q whereas the back side receives the four color safety background by an offset printing or a three-color background and also a monochrome main design by wet offset printing.

The above described mschine can be used without any difficulty as a web printing machine by simply replacing the sheet conveyor means with means for conveying a web of paper passing between blanket cylinders 12 and 13.

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Claims (4)

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1.Rotary multicolor printing machine for th* simultaneous printing of both aid** of a pap*r in w*b or ah**t form. mora particularly for printing the aaf*ty background of fiduciary documents, which compria*s a first blanket cylinder contscting a plurality of offset plate cylinders each inked by an inking device in a different color, the number of said offset plate cylinders corresponding to the number of colors and designs of the first image to be printed on one side of the paper, aaid r-v firat image consisting of superposed colors end designs. i " and comprising a second blanket cylinder operating as a color collecting cylinder contacting a plurality of selective color inking cylinders and a typographic plate cylinder, aaid typographic plate representing the complete design of the second image to be printed on the other aide of the paper. aaid selecting cylinders. of which the number corresponds to the number of colors of said second image and wherein the relief areas correspond to the portions of this image to be colored in the different colors, being each inked by an inking unit in • different color and applying an image with juxtaposed colors to said collecting cylinder inking in turn said typographic plate cylinder. a third blanket cylinder, contacting aaid typographic plate cylinder and receiving therefrom the image with juxtaposed colors, being pressed against said first blanket cylinder, said paper passing between said first and third blanket cylinders so as to be printed simultaneously on both sides with said first and second images, respectively.

2. Machine according to claim 1. characterized by the fact that at least one of said offset plate cylinders carries a wet offset printing plate with which m dampening ^■4"c e \ • device is associated, whereas the other offset plate f U.i v "t - 9 - r J 210951 cylinders carry dry off«*t printing plates.

3. Machine according to claim 1 . characterized by th* fact that it further comprim an offset printing unit, preferably a wet offsat unit of which th* plat* cylinder contacts th* third blanket cylinder .

4. Machine according to claim 1 , characterized by the fact that a double inking is provided for the typographic plate cylinder by means of two image transfer cylinders ATTORNEYS FOH THE APPLICANTS o 10