US2004136A - Printing cylinder - Google Patents

Description

June 11, 1935.

O. R. SCHULTZ PRINTING CYLINDER Filed March 3, 1931 flrzaa/ a %i%ia/fz fix 7 M M ATTORNEY Patented June 11, 1935 PATENT OFFICE PRINTING CYLINDER Oswald R. Schultz, New York, N. Y.

Application March 3, 1931, Serial No. 519,713

'7 Claims.

This inventionrelates to printing cylinders, and more particularly to a printing cylinder adapted to carry a removable printing form on the outer surface thereof.

In printing multi-color work, a separate printing cylinder for each color or tone is ositioned in the press and the various color parts composing the colored page are printed separately and consecutively. The color parts placed on the printed sheet by the respective printing cylinders must be in exact registry. Any overlapping of the color parts, or separation of the color parts so as to present a white line between the parts, indicates faulty printing work and is most undesirable.

The printing cylinder carrying the printing form is under a severe pressure strain when in operation in the printing press. If the form is not most securely fixed to the cylinder, a slight creepage or movement of the form with respect to the cylinder will occur after a certain operating period. This creepage, however slight, will produce overlapping of the color parts or separation of the color parts, and is generally fatal to good color work. No means have heretofore been devised to prevent this creepage and to secure the printing form to the printing area of the cylinder in a fixed and immovable manner.

An object of my invention is to provide a printing cylinder to which a printing form can be lmmovably and fixedly secured.

Another object of my invention is to provide a printing cylinder especially adapted for multicolor printing and gravuring work.

Another object of my invention is to provide a novel printing cylinder adapted to carry in combination a non-stretchable printing form with means to secure the form immovable to the cylinder during the most severe operating conditions, and thus obtain absolute registry of the color parts composing the work turned out.

Another object of my invention is to provide a printing cylinder especially adapted for multicolor printing, which, when a series of such cylinders are used with their respective color forms thereto attached, exact and precise registry of the color parts on the printed work will result.

Another object of my invention is to provide a printing cylinder adapted for multi-color work which is strong and durable, which can be easily and quickly adjusted to receive and immovably secure the printing form thereto, or to remove the printing form therefrom, and which is relatively inexpensive to make.

Still another object of my invention is to provide a method of applying a printing form to a printing cylinder quickly and eifectively, and in a firm, fixed and immovable manner.

Other objects of this invention will become evi- 5 dent as the disclosure proceeds.

In accordance with my invention I provide a printing cylinder having a semi-cylindrical rigid shell whose outer surface is smooth and round. The ends of the cylindrical shell are spaced apart 10 leaving an opening extending longitudinally along the surface of the printing cylinder; The spaced ends of the shell are connected together by an inwardly arched web portion to give the cylinder the required strength. The outer surface of the semi-cylindrical shell comprises the printing area of the cylinder. A printing form, which may be of a type disclosed in my co-pending application Serial No. 518,649 filed February 2'7, 1931 is secured about the outer surface of the semi-cylindrical shell in the following manner. One end of the printing form is clamped by means of a clamping bar and bolts to the cylinder at one end of the semi-cylindrical printing shell. A roller, extending the length of the cylinder, is then lowered upon the cylinder adjacent the secured end of the printing form. The printing cylinder is then rotated in such a manner that the roller moves over the printing form and presses the form into close contact with the outer surface of the semi-cylindrical printing shell. All uneven areas in the printing form are thus ironed out. When the roller has traveled over the entire area of the semi-cylindrical shell, the free end of the printing form is bent around the end of the semi-cylindrical shell. Another clamping bar is then positioned over the unsecured end of the printing form and bolted tightly to the cylinder near the end of the semi-cylindrical shell, thus clamping the printing form securely to the cylinder. The roller is then lifted off from the cylinder.

My printing cylinder is especially adapted for use in multi-color printing, where each cylinder carries a printing form prepared to print one color or tone of the work as completed. In my co-pending application above referred to, I'have shown and described a printing form especially adapted for multi-color work in that the form is non-stretchable, and permanently maintains its position on the printing cylinder through the most severe and continuous printing operations. My printing cylinder, as above described and shown in the accompanying drawing, provides an admirable mounting for a non-stretchable printing form, such as is disclosed in my co-pending application referred to above. With such a combination perfect registry of the color parts of the printed work is assured.

In order that a clearer understanding of my invention may be had, attention is hereby directed to the accompanying drawing, forming a part of this application and illustrating certain possible embodiments of my invention.

Referring to-the drawing, Figure l is a side view of my novel printing cylinder with a printing form secured thereto;

Figure 2 is an end view of my printing cylinder carrying the printing form, taken on line 22 of Figure 1;

Figure 3 is an enlarged cross sectional view of my printing cylinder with a printing form there-- to attached, the view being taken on line 33 of Figure l; and

Figure 4 shows a pair of my printing cylinders with a sheet being printed in two tone, this view being presented for the purpose of showing diagrammatically the exact registry of the color parts comprising the printed work which can be obtained by my novel printing cylinder and printing form combination.

Similar reference characters refer to similar parts throughout the several views of the drawmg.

In carrying out my invention, I provide a printing cylinder mounted upon a shaft IIl, which is adapted to be inserted in proper position in the printing press in the well-known manner. The novel features of my printing cylinder consist in the particular construction of the drum or printing form supporting portion. The drum consists 'of a substantially completely cylindrical shell portion II positioned concentrically about the shaft II]. The shell I I may be made of cast metal or other suitable rigid and strong material. The outensurface of the shell is, as above noted, absolutely circular and smooth except for a short distance on the circumference where spaced longitudinal edge portions I2 and I3 are formed in the shell. A comparatively narrow channeled opening extending longitudinally of the cylinder is' thus presented, as clearly shown in Figure 1, being constituted of and comprising an inwardly arched web portion I4, which may be cast integrally with the shell II, to form a longitudinal channel therein connecting and joining the edge portions I2 and I3 of the shell and give the requisite strength and rigidity to the cylinder. The thickness of the shell II is not material as long as absolute rigidity is assured. The printing area of the cylinder comprises the outer area presented by the circular shell II and extends from one longitudinal edge. I2 of the shell around the surface of the shell to the other like edge I3. Each end of the cylinder is closed by a suitable plate I5, as shown more particularly in Figure 2. The shaft I 0 extends through and is secured to a hub portion I6 provided on each closure plate I5.

I have shown for purpose of illustration only one type of rigid, non-stretchable printing form especially adapted for use in conjunction with my printing cylinder. Referring more particularly to Figure 3, this printing form comprises generally a non-stretchable backing plate I'I, having a layer of cellulosic or similar material I8 fixedly and immutably secured thereto. The top surface of the cellulosic sheet I8 carries an embossed impression I9, as appears in Figure 3.

As fully described in my copending application above referred to, the printing impressions are embossed in the cellulosic material while the same'is in a solubilized plastic condition by rolling the plastic mass in contact with a water swollen gelatin copy relief having photographically toned printing impressions in relief thereon. The plastic cellulose mass receives the minute impressions of the copy relief and when hardened presents a printing plate which is delicately toned and shaded so as to accurately reproduce on the sheet printed therefromthe original object photographed. It is understood that I do not limit myself to this particular type of printing form in combination with my printing cylinder, but any printing form of plasticizable material having toned printing impressions therein which will not stretch when applied to and in operation with the printing cylinder.

Clamping means are provided at each longitudinal edge portion I 2 and I3 of. the substantially cylindrical shell II to fixedly secure the printing form to the cylinder. More particularly I provide a fiat clamping bar at each edge portion of the longitudinal channel of the shell, which as described extends the full length of the cylinder. A number of heavy machine bolts 2| extend through each such clamping bar 20 at spaced intervals, and engage threaded apertures 22 provided in the channel edges I2 and I3. By suitably manipulating the bolts 2I, the end portions 23 and 24 of the printing form may be substantially and securely clamped to the respective channel edges I2 and I3 of the cylindrical shell II.

It is important that the printing form be tightly and smoothly secured to the surface of the cylindrical shell. The method of accomplishing this result will now be described. The end portion 23 of the printing form is bent around the edge I2 of the longitudinal channel of the substantially cylindrical shell. One of the clamping bars 20 is then placed over the end portion 23, and bolts 2| inserted through the bar and into the threaded apertures 22. The bolts 2| are then adjusted so as to securely clamp the end portion 23 of the printing form between channel edge I2 of the shell and the clamping bar 20. A suitable roller 25 composed of rubber or the like material which will not injure the delicately toned printing surface is then lowered so as to rest on the cylinder adjacent the channel edge I2. The cylinder is then slowly rotated on its shaft I6 in a clockwise direction, as indicated by the arrow in Figure 2, the roller 25 preferably remaining stationarys Pressure is applied to the roller 25 sufficient to iron the printing form smoothly and evenly against the outer surface of the cylindrical shell II. It will be seen that as the cylinder rotates the roller also smooths out all buckles and uneveness in the printing form, and also takes up all slack between the roller and the end portion 23 of the printing form already secured to the channel edge portion I2 of the shell. When the cylinder has been rotated to the point where the roller 25 is in a position adjacent to the cooperating channel edge portion I3 of the cylinder, rotation of the cylinder is stopped. Then end portion 24 of the printing form is bent smoothly around the edge portion I3 of the shell and securely clamped to the said edge portion I3 by means of another clamping bar 20 and bolts 2|, as before. The roller 25 is then lifted off from the printing cylinder. The cylinder with the printing form thereto attached is now ready for insertion in the printing press.

- comprising r referred to.

I have shown diagrammatically in Figure 4 a general assembly of my printing cylinders with a rigidly mounted, non-stretchable printing form thereto secured, as used in multi-color printing. The cylinder A, constructed as shown in Figures 1, 2, and 3, carries the printing form having the toned impressions embossed on the outer surface HM, and the cylinder B carries a printing form having the toned impressions embossed on the outer surface I92). The surfaces I91; and I9?) are generally embossed so that each prints one color only. For purposes of illustration, let it be assumed that cylinder A prints upon the paper or fabric sheet 26 the triangle 21a and the circular segment 28a in red color. Let it be assumed that the embossed impression I9b carries the counterpart triangle 21b and the counter-part circular segment 28b in blue color. At the outset of the printing operation cylinders A and B are so positioned in the printing press that the margin line 29a. of triangle 21a and margin line 30a of circular segment 28a will exactly coincide with the respective margin lines 29b and 3017 when this portion of the sheet reaches cylinder B and the counterpart triangle 21b and counter-part circular segment 28?) are printed upon the sheet. It is absolutely essential that the cylinders A and B and printing forms thereto attached maintain this absolute relationship if the different color parts of the printed work are to be in proper registry so that there will be no overlapping or separation of the red and blue. The slightest flexibility present in the printing cylinder, the slightest creepage of the form with respect to the cylinder, or the least stretch which occurs in the printing form will, as is evident, produce work in which the color parts fail to register.

I have been able to obviate these difiiculties and obtain perfect registry of the color parts the printed work over indefinite periods of continuous printing by the use of my printing cylinder in combination with a rigidly mounted, non-stretchable printing form, such as disclosed in my co-pending application above The printing form is quickly applied by the method which I have disclosed, and when so applied remains immovable upon the printing cylinder. The clamping means, comprising the clamping bar 20 and bolts M, are hidden within the longitudinal channel formed by arcuate web l4 and thus do not interfere in anyv way with the printing work, and yet are easily accessible for adjustment. My printing cylinder, as above constructed, is durable, perfectly rigid, and easily made of inexpensive materials.

As many changes could be made in the construction and, method of application above outlined, and as many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

, What I claim is:--

1. An improved clamping system for printing cylinders, comprising a longitudinal channel in the cylinders, said channel having parallel sides and an integral arcuate web joining same, and parallel clamping bars adjustably and removably secured to said parallel sides.

2. In combination, a printing form comprising a backing portion of non-stretchable material, a

having toned printlayer of cellulosic material ing form being arranged on the cylinder in such a manner that the ends of the backing portion overlap the spaced parallel edges of said shell, and means for clamping the overlapped ends of the backing portion to the said parallel spaced edges of said shell, said clamping means comprising a fiat bar disposed over each overlapped edge and bolts extending through said bars and into the cylinder.

3. In combination, a printing form comprising a backing portion of non-stretchable material, a

layer of cellulosic material having toned printing impressions embossed in the surface thereof immutably secured to said backing portion said layer being substantially co-extensive with said backing portion, and a cylindrical printing shell having a longitudinal channel in said cylinder, the edges of said channel being spaced apart, said cylinder having a printing area substantially co-extensive to said form, said printing form being arranged on the cylinder in such a manner that the ends of the backing portion and said layer of cellulosic material overlap the spaced edges of said shell, and means for clamping the overlapped ends of said form to the cylinder whereby the edges of the cellulosic material are interposed between the clamping means and the cylinder so as to retain the form immove able thereon.

4. In combination, a printing form comprising a solubilized cellulosic layer having toned printing impressions embossed thereon, said layer being immutably secured to a non-stretchable backing sheet and said layer extending substane tially co-extensive with the backing sheet, a printing cylinder adapted to carry said form on the cylindrical surface thereof, and means directly abutting the said layer and clamping the backing sheet to said cylinder to retain the form immovable thereon.

5. In combination, a printing form comprising a. backing portion of non-stretchable material, a layer of cellulosic material having toned printing impressions embossed in the surface thereof immutably secured to said backing portion throughout its area, a cylinder having a rigid cylindrical printing area substantially coextensive with the printing area of said form, and means directly abutting the end portion of the cellulosic layer for clamping the backing portion to said cylinder to retain the form immovable thereon.

-6. In combination, a printing form comprising a cellulosic layer having toned printing impre'ssions embossed thereon, said layer being autogeneously bonded to a, metal backing sheet, a printing cylinder having a longitudinally extending channeled portion and a printing area substantially coextensive with the printing area of said form, and means directly abutting the said layer and acting therethrough to clamp the backing sheet to said cylinder to retain the form immovable thereon.

7. Apparatus for multi-color printing including in combination, a plurality of cylinders, a printing form adapted to print a color part assoing the backing sheet to the associated cylinder so as to retain the embossed impressions and the cellulosic layer fixed and immovable, insuring absolute registry of the color parts onthe finished printed work.

OSWALD R. SCHULTZ.

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