US2270273A - Convertible printing press - Google Patents

Description

Jan. 20, 1942. w, w. vmso 2,270,273

CONVERTIBLE PRINTING PRESS Filed Sept. 6, 1939 Patented Jan. 20, 1942 UNITED STATE s I PATENT OFFICE CONVER TIB LE PRINTING PRESS I William Ward Davidson, Evanston, 111.

Application September 6, 1939, Serial No. 293,554

6 Claims.

The present invention relates to printing presses generally and more particularly to presses which are convertible to perform different printing processes.

Three common classes of printing processes are: lithographic, intaglio, and type printing.-

With more and greater uses being'made of commercial printing, it has become increasingly important that users or printers have one or two convertible presses to take care of their requirements rather than a greater number of presses which are limited in their operation to the perchangeable upon one cylinder and the litho-.

graphic plate of another cylinder is converted into an ink form roller surface for the type segment, whether the press be of two cylinder or three cylinder construction.

Another purpose of the invention is to provide a press which is convertible without need for changing the inking mechanism of the press. 1

Moreover, I provide a convertible press with these characteristics that prints the paperupon the same side whether it is the bottom or the top.

Other objects will become apparent from the drawing, the description relating thereto and the claims.

Referring now to the drawing:

Fig. 1 illustrates a two cylinder rotary press set up for indirect lithographic printing;

Fig. 2 illustrates the press shown in Fig. 1 conv verted for direct type printing;

Fig. 3 illustrates a three cylinder press embodying the invention as set up for indirect lithographic printing; and r Fig. 4 is a press shown in Fig. 3 as converted for direct letter press work.

Broadly speaking, without changing the inking characteristics of the hiking unit or its osition I convert the blanket cylinder of a lithographic couple into a direct or type printing cylinder and interchange the plate of the couple with a composition covering which cooperates with the inking unit as an added form roller for the type printing cylinder.

In Figs. 1 and 2 this convertibility is shown in relation to a two cylinder press comprising a printing couple with a blanket cylinder l located above a larger cylinder H having a platen segment 12 and a plate segment l3. Blank sheets of paper are fed from the conveyor board I by the feed rollers l5 which are synchronized to feed a sheet into the bite of the cylinders between the platen i2 and the, blanket III. A leading overlap of the sheet is provided at the gap l6 so that the stripper I! may be tilted into the gap to catch the leading edge of the sheet and direct it onto the delivery table H.

The ink applying rollers are indicated at and comprise the fountain roller 2|, the ductor roller 22, the distributor roller 23 and the ink form when 24. The water damping mechanism comprises the fountain roller 25, the water ductor roller 26, the water distributing roller 21 and the water form roller 28. The form rollers 24 and 28 are lifted to clear the platen l2 each revolution of the cylinder II by a cam 30 thereon which does not engage cylinder ID or affect the tion covering 32 is fastened in its place.

covering is preferably surfaced with a material pressure of the printing couple.

As shown in Fig. 2, whenever it is desirable to convert the two-cylinder embodiment into a direct or type press, the blanket is removed from the blanket cylinder l0 and a cast type plate 3| is slipped endwise onto the cylinder Hi, the frame work of the press (not shown) being cut away to permit this.

The plate I3 is then removed and a composi- This similar to that upon the form roller 23 and when in operation the form roller 23 becomes in substance a second distributor roller and the covering 32 becomes the form roller.

Thus, when the conversion is made for direct and letter type printing, the inking system remains physically unchanged although greater distribution is had, and it remains only to remove the water form roller from contact with the cylinder II to place the press in full operation for direct printing.

In both forms of the conversion, whether the form in Fig. 2 is considered the initial construction adapted to be converted for lithographic printing, or whether the form in Fig. l is considered theinitial construction, conversion may be had readily and quite easily even by persons unskilled in printing, and in both cases the blank sheets are printed on the same side, in this instance-upon the upper side.

Referring nowto Figs. 3 and 4, a three cylinder press is illustrated as converted from performing one form of printing to performing another. The numerals and description relating to water and ink distribution remain the same, ex-

are located at the top of the press where they are open for ready'inspectlon.

The three cylinders comprise in the lithographic printing couple the plate cylinder 40 at the top, the platen 4 at the bottom, and a blanket cylinder 42 between them.

In this embodiment, the contour .of a side frame is indicated in broken lines 43 in Fig. 4. The side frame at least on one side of the press is cut away to permit the endwise movement of the cast type segment 44 to be moved into and out of place upon the intermediate cylinder.

Whenever it is desirable to change one form of printing to another, the plate 45 is interchanged with a composition ink distributing covering t6 and the blanket 41 is interchanged with the cast type segment 44.

In both'the three and two cylinder constructions, I prefer to have the conversion performed in relation to the pitch line of the meshing gear teeth. In doing this, the bed surfaces supporting the plates in the several views are relieved enough to accommodate the thickness of the composition coverings 32 and 46 without changing the printing radius of the cylinders. With this construction, I provide a foundation covering for the bed when the plates are mounted. 'Ifhis foundation may be secured to the plate before mounting or, as preferred, is fastened over the bed surface before the plate is mounted.

In this Way I adjust for and maintain the proper printing couple line of pressure contact in relation to the pitch line of the gear teeth driving the cylinders for both forms of printing,

on either the two cylinder or the three cylinder press.

In some instances it is desirable to have multigraph type upon the blanket cylinder. I

taining the relationship between the line of the In mainwith the presses that are intended for multigraph conversion.

-Having described several embodiments of the invention and suggested the manner in which they are believed to function and operate, it will be apparent to those skilled in the art that var-' ious uses, modifications, and changes may be made therein without departing from the spirit and substance of the invention, .the scope of which is commensurate with the appended claims.

What is claimed is: 1

1. A convertible printing press comprising a small cylinder disposed above a large cylinder, interchangeable blanket and direct printing means for the small cylinder, a platen surface upon the large cylinder cooperating with the small cylinder to provide a printing couple, interchangeable plate and ink form surfaces for the large cylinder cooperating with the small cylinder to provide an ink transfer medium, and

means for inking the interchangeable surfaces upon the large cylinder.

6 2. A printing press comprising a blanket cylinder supported above theline of feed of paper to the printing couple, a larger cylinder disposed below said line of feed and providing a platen surface and a plate surface cooperative'with the 10 blanket cylinder for lithographic printing, an

inking mechanism contacting the plate surface each revolution of the larger cylinder, ink form surface means interchangeable with theplate, and direct printing means interchangeable with the blanket.

3. A convertible printing press for lithographic offset printing ordirect printing, comprising a small cylinder and a cooperating large cylinder, a blanket surface on the small cylinder interchangeable with direct-printing means, a platen surface on the large cylinder, and a lithographic plate surface on the large cylinderinterchangeable with an ink form surface.

4. A convertible printing-press for lithographic offset printing or direct-printing, comprising a small cylinder and a cooperating large cylinder, a blanket surface on the small cylinder interchangeable with direct-printing means, a platen surface on the large cylinder, a lithographic plate 30 surface on the large cylinder interchangeable with an ink form surface, and an inking mechanism for supplying ink to a portion of the large cylinder whether that cylinder'supp rts a lithographic surface'or an ink form surface.

offset printing or direct printing, comprising a printing couple consisting of a small upper cylinder and a cooperating lower cylinder having a diameter twice that of the small cylinder, a

40 blanket surface on the small cylinder interchangeable with direct-printing means,- a platen surface on the lower cylinder, a lithographic plate surface on the lower cylinder interchangeable with an ink form surface, and an inking mechanism associated with the lower cylinder for supplying ink to a portion of said lower cylinder whether supporting a lithographic surface or an ink form surface.

6. A convertible printing press for lithographic n offset printing or directprinting, comprising a small cylinder and a cooperating large cylinder,.

a blanket surface on the' srnallfcylinder interchangeable with direct-printing .nicans a platen surface on the large cylindrffa lithographic plate surface on the large cylinder interchangeable with an inig'form surface, a single inking -mechanism for'supplying ink for either of said "types of printing, said inking mechanism being arranged to apply ink directly to the lithographic m plate surface when the press is doing lithographic offset printing, and to the ink form surface which in turn transfers the ink to the direct-printing means when the press is doing direct printing.

' WILLIAM WARD DAVIDSON.

5. A convertible printing press for lithographic

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