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Publication numberUS3928038 A
Publication typeGrant
Publication dateDec 23, 1975
Filing dateFeb 28, 1974
Priority dateFeb 28, 1974
Publication numberUS 3928038 A, US 3928038A, US-A-3928038, US3928038 A, US3928038A
InventorsBergin Michael J
Original AssigneeIntaglio Service Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Process for making multi-color intaglio plates and cylinders for use in gravure printing
US 3928038 A
Abstract
In a photogravure process for making sets of intaglio plates for use in multi-color gravure printing a special type of halftone screen is used in a special manner. Said screens are characterized by closely spaced parallel lines of connected dots extending in a single direction as distinguished from crossed lines of discrete dots as in halftone screens used in offset lithography, and from the crossed solid lines of the screens commonly used in photogravure processes. A set of such screens is assembled with a set of continuous tone color separated positive transparencies with the lines of connected dots of each screen arranged at an angle to the horizontal which is different from the angle to the horizontal at which the corresponding lines of connected dots of each other screen are arranged. The said assemblies are then exposed separately onto photosensitive material and the latent images are transferred onto a copper plate in conventional manner and the plates are then etched in conventional manner.
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Description  (OCR text may contain errors)

United States Patent [191 Bergin PROCESS FOR MAKING MULTI-COLOR INTAGLIO PLATES AND CYLINDERS FOR [52] US. Cl. 96/38; 96/45; 96/116 [51] Int. Cl. G03F 5/00; G03F 7/24 [58] Field of 96/38, [16, 45

[56] References Cited UNITED STATES PATENTS 6/1902 Szczepanik 96/45 2/1935 Grenell 96/116 2,480,400 8/ 1949 Dultgen 2,700,609 l/l955 Landom...

3.024,l ll 3/l962 Sportelli.....

3,804,622 4/1974 Bergin 96/38 OTHER PUBLICATIONS Photo Mechanics and Printing, Mertle et al., 1957, pp. 144-145.

[ Dec. 23, 1975 Primary Examiner-Mary F. Kelley Attorney, Agent, or Firm-Nichol M. Sandoe [57] ABSTRACT ln a photogravure process for making sets of intaglio plates for use in muIti-color gravure printing a special type of halftone screen is used in a special manner. Said screens are characterized by closely spaced parallel lines of connected dots extending in a single direction as distinguished from crossed lines of discrete dots as in halftone screens used in offset lithography, and from the crossed solid lines of the screens commonly used in photogravure processes, A set of such screens is assembled with a set. of continuous tone color separated positive transparencies with the lines of connected dots of each screen arranged at an angle to the horizontal which is different from the angle to the horizontal at which the corresponding lines of connected dots of each other screen are arranged. The said assemblies are then exposed separately onto photosensitive material and the latent images are transferred onto a copper plate in conventional manner and the plates are then etched in conventional manner.

8 Claims, 5 Drawing Figures PROCESS FOR MAKING MULTI-COLOR INTAGLIO PLATES AND CYLINDERS FOR USE IN GRAVURE PRINTING This invention relates to photogravure processes and pertains more particularly to processes of making sets of intaglio plates including both flat plates and cylinders for use in multicolor gravure printing. It will be understood that the term plates as used hereinafter includes both flat plates and cylinders.

It is an object of the invention to improve the quality of the intaglio surfaces formed in such plates by the use of a special type of halftone screen used in a special manner, whereby an improved lay of ink is obtained which results in smoother printing and helps to eliminate phenomena known in the trade as skipping and picking" which result in unevenesss and white specks in the printing. The quality of the prints made from such plates is improved.

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment of the invention is shown in the accompanying drawings, in which FIG. 1 is a greatly enlarged plan view of a small section of a halftone screen as used in the process of the invention FIGS. 2, 3, 4 and 5 are diagrammatic representations of a set of halftone screens illustrating the angles at which the lines of connected dots of the respective screens are arranged for use with a set of four color separated continuous tone positive transparencies corresponding to four different colors.

The practice of the invention depends importantly on the use, in a novel manner, of a special type of halftone screen which is characterized by closely spaced parallel lines of connected dots, as distinguished from crossed lines of discrete dots as in the usual halftone screens commonly used in offset lithography, and as distinguished from the crossed solid lines of the screens com monly used in photogravure processes.

Such a halftone screen is illustrated in greatly enlarged scale in FIG. I in which all of the dots 1 of each of the lines of dots are connected together, in the manner of a chain of dots, by narrow necks 2 of a width considerably less than the maximum width of the dots. Moreover, as shown in FIG. I, all of the lines of connected dots are parallel and extend in a single direction. The opposed dots of adjacent lines of dots are not connected. The maximum width of the dots is preferably less than the distance between opposed dots of adjacent lines. In the use of such screens in this process, the said lines of dots are commonly arranged 100 to 250 lines per inch.

In the use of such screens in the making of sets of color separated intaglio plates for use in multi-color gravure printing, the lines of connected dots of each screen are arranged at a predetermined angle to the horizontal, i.e., to a transverse line which extends in a direction perpendicular to the direction of movement of the paper on which the image is printed as it moves through the press. as indicated by the transverse horizontal lines 3. The direction of movement of the paper is indicated by arrows 4. In the following description of the invention, the predetermined angles of the lines of connected dots are related to the horizontal as above defined.

Moreover, in the use of such screens in the making of sets of color separated intaglio plates for use in multicolor gravure printing, the predetermined angle at which the lines of connected dots of each screen are arranged with respect to the horizontal is different from that of each other screen. That is, in the case of four color process printing, for example, in which four separate screens as shown in FIGS. 2, 3, 4 and 5 are used in connection with yellow, red, blue and black color separations, respectively, the angle at which the lines of connected dots of each screen are arranged with respect to the horizontal will be different for each color as hereinafter explained.

The invention may be best understood with reference to a specific example of its use in a four color process, and for clarity and completeness, the entire process leading to the making of a set of four finished intaglio plates will be described, although it will be understood that many of the steps described are conventional in the art. The principal novelty of the invention resides in the use of screens as above described in the particular manner described in Steps 3 and 4 hereinafter.

STEP 1. The first step in the process is the photographing and developing by conventional processes of a set of four color separated continuous tone negative transparencies corresponding to four different specific primary colors as, for example, yellow, red, blue and black, preferably color corrected and retouched if necessary.

STEP 2. A set of four continuous tone developed positive transparencies is now made from said four negative transparencies by conventional processes, as by contact printing.

STEP 3. A set of four positive halftone screens of the type shown in FIG. 1 and heretofore described is now prepared, each of said screens being of equal value, i.e., the lines of connected dots of the respective screens are identical except as to their angulation, and the number of lines per inch is identical. The lines of connected dots of each screen are arranged at a specific angle with respect to the particular continuous tone positive with which it is to be assembled, which said angle is different from the specific angle at which the lines of connected dots of each other screen are arranged with respect to the particular continuous tone positive with which it is to be assembled. In general, the predetermined angles of the lines of connected dots to the horizontal should all exceed 45 in order to avoid doctor blade chatter and spillout of ink. Thus, in the case of screens intended for assembly with yellow, red, blue and black continuous tone positives as previously described and as shown in FIGS. 2, 3, 4 and 5, the lines of connected dots 5 of the screen of FIG. 2 which is to be assembled with the yellow positive should be arranged at an angle of (:3) to the horizontal as previously defined; the lines of connected dots 6 of the screen of FIG. 3 which is to be assembled with the red positive should be arranged at an angle of 49 (13) to the horizontal; the lines of connected dots 7 of the screen of FIG. 4 which is to be assembled with the blue positive should be arranged to an angle of (t3) to the horizontal; and the lines of connected clots 8 of the screen which is to be assembled with the black positive should be arranged at an angle of I07 (:3") to the horizontal.

STEP 4. Each of the four continuous tone positives is now assembled in contact with its respective related screen on a line carrier plate known and sometimes referred to in the trade as a cabriolet. That is, the yel- 3 low positive film is assembled with a screen such as shown in FIG. 2 in which the lines of connected dots are at an angle of 75 to the horizontal; the red film is assembled with a screen such as shown in FIG. 3 in which the lines of connected dots are at an angle of 49 thereto and so on.

STEP 5. Each of the above assemblies is now exposed separately onto photosensitive resist material, such as carbon tissue, to form a latent image thereon, and the photosensitive material is then transferred and adhered to a copper plate.

STEP 6. The plates may now be etched in the conventional manner to form intaglio images therein. However, for best results, it is preferred to etch each plate with three irons of progressively decreasing baume for a total period of eight minutes at 69.5F. with the total periods divided as follows:

If desired, the method of producing halftone positive films described and claimed in my co-pending patent application Ser. No. 315,030, filed Dec. 4, 1972 may be combined with the present process in order to avoid jagged edges along the marginal edges of the images which may be caused by the varying angulations of the respective halftone screens.

What is claimed is:

l. A process of making a set of color separated intaglio plates for use in multi-color gravure printing which comprises the steps of making a set of continuous tone color separated positive transparencies, each of which bears a color separated image corresponding to a specific color different from the specific color of each other image, and assembling each of said transparericies separately with a transparent halftone screen having closely spaced parallel lines of connected opaque dots extending in a single direction, said dots being ofa length greater than their width and with successive dots connected by narrow necks of a width substantially less than the maximum width of the dots with said lines of connected dots of each of said screens arranged at an angle to the horizontal which is different from the angle to the horizontal at which the corresponding lines of connected dots of each other screen are arranged.

2. A process according to claim I in which the maximum width of said dots is less than the distance between opposed dots of adjacent lines.

3. A process according to claim 1 in which all of said lines of connected dots are arranged at angles to the horizontal which exceed 45.

4. A process according to claim 1 in which said set of continuous tone positive transparencies includes one bearing a yellow image. one bearing a red image, one bearing a blue image and one bearing a black image, and in which the lines of connected dots of the screen assembled with the transparency bearing the yellow image are arranged at an angle of (:3") to the horizontal, the lines of connected dots of the screen assembled with the transparency bearing the red image are arranged at an angle of 49 ("i-3) to the horizontal, the lines of connected dots of the screen assembled with the transparency bearing the blue image are ar' ranged at an angle of (:3") to the horizontal, and the lines of connected dots of the screen assembled with the transparency bearing the black image are arranged at an angle of 107 (t3) to the horizontal.

5. A process according to claim 1 which includes the step of exposing each of the said assemblies onto photosensitive material to form a latent image thereon, transferring each of said latent images onto a separate copper plate, and etching each of the said plates separately to form an intaglio image therein.

6. A photogravure process for making a set of color separated intaglio plates for use in multieolor gravure printing in which a set of continuous tone color separated positive transparencies, each of which bears a color separated image corresponding to a specific color different from the specific color of each other image is assembled with a set of halftone screens, and in which each assembly is exposed separately onto photosensitive material to form a latent image therein, in which the improvement comprises assembling each of said continuous tone color separated positive transparen cies separately with a transparent halftone screen having closely spaced lines of connected dots, said dots being of a length greater than their width and with successive dots connected by narrow necks of a width substantially less than the maximum width of the dots with each screen arranged at an angle to the horizontal which is different from the angle to the horizontal at which the corresponding lines of connected dots of each other screen are arranged.

7. A process according to claim 6 in which the maximum width of said dots is less than the distance between opposed dots of adjacent lines.

8. A process according to claim 6 in which all of said lines of connected dots are arranged at angles to the horizontal which exceed 45.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US701775 *Mar 19, 1900Jun 3, 1902Inv S Jan Szczepanik & Cie Soc DJacquard-card and method of making same.
US1990231 *Sep 9, 1932Feb 5, 1935Grenell Ralph WMethod of making half tone screens
US2480400 *Dec 30, 1944Aug 30, 1949News Syndicate Co IncMethod of making gravure printing plates
US2700609 *Dec 16, 1953Jan 25, 1955News Syndicate Co IncMethod of making intaglio engravings
US3024111 *Jul 21, 1958Mar 6, 1962Gravure Entpr IncGravure
US3804622 *Dec 14, 1972Apr 16, 1974Intaglio Service CorpMethods of producing halftone positive films
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4155766 *Dec 21, 1976May 22, 1979Helmut HieberHalf tone screen for rotary gravure printing
US4262070 *Apr 18, 1980Apr 14, 1981Liu Hua KuangMethod of making halftone contact screens
US5283140 *Nov 23, 1992Feb 1, 1994Yoel NetzHalftone image screening array of parallel lines with effective maximum and minimum optical density and method of generating a halftone image utilizing the screening array
US6163382 *Feb 20, 1998Dec 19, 2000Netz; YoelDevices and methods for offset and similar printing systems
US6697170Dec 18, 2000Feb 24, 2004Arnold HoffmanDevices and methods for offset and similar printing systems
US7343855 *Dec 16, 2004Mar 18, 2008Koenig & Bauer AktiengesellschaftOffset waterless printing press having a screen roller with ceramic coating and surface markings
US20050150405 *Dec 16, 2004Jul 14, 2005Georg SchneiderPrinting press with at least one printing group
CN103213415A *Mar 13, 2013Jul 24, 2013上海印钞有限公司Method for making latent image pattern with color changing effect by adopting silk-screen and offset printing processes
CN103213415B *Mar 13, 2013Jul 22, 2015上海印钞有限公司Method for making latent image pattern with color changing effect by adopting silk-screen and offset printing processes
EP0409608A2Jul 19, 1990Jan 23, 1991Yoel NetzMethod for offset and similar printing systems
EP0409608B2Jul 19, 1990Jan 10, 2007Hoffman, ArnoldMethod for offset and similar printing systems
Classifications
U.S. Classification430/301, 430/396, 101/170, 430/307, 430/6
International ClassificationG03F5/20, G03F5/00
Cooperative ClassificationG03F5/20
European ClassificationG03F5/20