US924016A - Blanket for lithographic presses. - Google Patents

Description

F. A. TESSMER.

BLANKET FOR LITHOGRAPHIG PRESSES.

APPLICATION FILED MAY 11, 1907.

Patented June 8, 1909 coextensive .wit

()FFHfil-t.

UnrrED E? FRANK A. TESSMER, OF'ST. LoUrs, nrssounr.

Brahma. i on LI'IHOGRAPHIC rnnss'ns.

Specification of Letters Patent.

Patented June 8, 1909.

Application filed Hey 11,1967. Serial No. 373,086.

Louis, in the State of Missouri, have invented new and useful Irn rovements in Blankets for Lithographingresses, of which the following is a specification. V

"This invention relates to a blanket for litho gfaphing presses, and it has for'one of its o jects to provide a blanket which is economical, flpossesses comparatively longlife, hi hly e of pro ucin clearer impressions than is ordinarily ossible.

In t e common form. of printers blankets for lithographin presses, the rubber .pad is the canvas backing to which it is attached so that the entire surface of the cylinder is covered; This has been objectionable for the reasons that at the best, the blanket can be used for only two or three months because the rubber, is subjected to the action of ink, aint, oil, turpentine, benzin, water and acid on'the parts that are not covered by the sheet to ire-printed, and furthermore, there is considerable waste since the entire surface of the rubber is not employed to form the cushion or printing surface and due to the fact that the blanket or cushion covers the entire surface of the cylin der, it is impossible to obtain a sharp and clear impression. 1

I overcome the objections above noted by em loying a blanket in which the cushion or rub er forming the printing surface is no longer than the sheet to be printed, thereby greatly reducing the cost of the blanket, since there is no superfluous amount of rubcient in operation, andcapable her in the blanket, and since the sheet to be printed covers the superficial area of the ruber pad or cushion, no parts of'the latter are exposed to the injurious effects of oil, water,

acid, tur entine and the like.

A stil further advantage accompanying the use of my improved printing blanket is the production of a much sharper impression than usual for the reason that the pad or. cushion bears only on the parts to be printed and not u on the entire surface of the stone, as is usua y the case with presses now in use.

With these objects in view and others, as will appear as thedescription proceeds, the invention comprises the various novel features of construction and arrangement of parts which will be more fully described heretion is about three times t inafter and set forth with particularity in the claim appended hereto.

. 1 In the accompanying drawing, which illustrates one of the embodiments of the invention, Figure 1 is a transverse section of a cylinder showing the improved blanket applied thereto.

scale. Fig. 3 is a fragmentary sectional view of a modified form' of blanket showing a double ply cushion or pad.

Similar reference characters are employed to designate corresponding parts throughout the several views.

, Referring to the drawing, 1 designates a c linder of the type usually employed ina 0e lithograph press which is provided with a longitudinally-extending gri per having teeth ,or pins 2 to which the b anket is attached at one edge and a stretching rod 3 having teeth or pins 4 and extending longitudinally of the cylinder at a point a proximately diametrically opposite from t e clipper; said stretcher being provided in the usual manner with a ratchet and awl mechanism (not shown), whereby the lanket can be tightly stretched. In the present instance, the blanket comprises a canvas back- .ing 5 that has its longitudinal edges attached respectively to the gripper and stretcher. On the canvas is a'rubber ad or cushion 6 which is just the size of the s eets to be printed and this rubber pad is secured to the canvas by first ap lying a coat of rubber cement 7 to the blanl et over an area equal to the cushion and placing a sheet of linen auze 8 Fig. 2 is a transverse section oi" the blanket removed, drawn on an enlarged to whicha'cbat of rubber cement or t e like,

is applied, for receiving the sheet of'rubber 6.

Besi es serving as a binder, the linen gauze holds the pad a considerable distance above the surface of the canvas and the total thickness of the blanket at the ad or cushion orhe thickness 0 the canvas backing. A blanket constructed in this manner is of-the single ply type and under some conditions, it maybe preferable to increase the number of the plies. In a multiple ply blanket, a sheet of hnen gauze 9 is cemented to the first sheet of rubber and a second sheet of rubber 10 is cemented to. the

gauze 9, as clearly shown, in Fig. 3. After tion is carried on in the usual manner and iii since the pad or cushion of the blanket is only produced.

In. order to illustrate the economy of a blanket oi the present construction, assume that it is desired to employ the blanket one.

medium sized lithographing press having a cylinder taking an ordinary blanket of thirty-six by forty-two inches, it is well known that the ia'rgest sized sheet that can be printed is twenty-eight by forty-two inches, which leaves a total waste of rubber in the blanket of forty-two inches long and eight inches wide, or three hundred and thirty-six square inches. Besides being unnecessarily expensive, the blanket hash large area exposed to the deleterious effects of oil, acid, water and the like, and the entire surface of the blanket comes in contact with the stone. With the present form of blanket, however, the cushion will beonly twentyeight by forty-two. inches, which is the size of the sheets printed, thus reducing the cost about one fourth and increasing the life of the blanket/from two to three months, as usual in the ordinary blanket, to live or months. VVith still smaller sheets to be printed, the economy would be even greater, as will be readily understood by those famih' iar with the lithographic printing".

From the foregoing description, taken in connection with the accompanying drawing, 1

; together with the apparatus which I now consider to be the best embodiment tl'iereof, l. desire to have it understood that the apparatus shown is merely illustrative and that 3 such changes may he made when desired, as

are within the scope of the claim.

Having thus described the invention, what I. claim 15:-

The herein described blanket for llil1 graphic printing presses consisling of :l ':m-

vas backing, a piece of fabric secured to the backing by cement, and a rubber impression pad secured to the piece of fabric by ccment, said fabric and pad being of snbstantially the size of the sheet to be print d r and the canvas backing being of greater length than the fabric and pad, whereby the bucking is adapted to be secured'io the blanket attaching devices of the press.

In testimony whereof, I. alilx my signature in presence of two witnesses.

FRANK Witnesses:

JAs. H. SonnNK, Enwi). Monnin'rr.

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