US2540667A

US2540667A - Sheet fed offset perfecting press

Info

Publication number: US2540667A
Application number: US604758A
Authority: US
Inventors: Charles W Harrold; Alfred S Harris
Original assignee: Harris Seybold Co
Current assignee: Harris Corp
Priority date: 1945-07-13
Filing date: 1945-07-13
Publication date: 1951-02-06
Anticipated expiration: 1968-02-06

Description

Feb. 1951 c. w. HARROLD ET AL SHEET FED OFFSET PERFECTING PRESS Filed July 15, 1945 2 Sheets-Sheet 1 Hal \ i INVENTORS CHAIQLES W HHEEOLD BY ALF/e50 5. HA/e/e/s Feb. 6, 1951 c. w. HARROLD ET AL 2,540,667 SHEET FED OFFSET PERFECTING PRESS I 2 Sheets-Sheet 2 Filed July 13, 1945 IN VE 'VTORS H W mam. m L5 N ee R M m n T CW W Patented Feb. 6, 1951 SHEET FED OFFSET PERFECTING PRESS Charles W. Harrold. Universitv Heights. and Alfred S. Harris. C eveland Heights, Oh o. assignors to Harris-Seybold Company, a corporation of Delaware Application July 13, 1945, Serial No. 604,758

6 Claims.

Another object is the provision of a press of low cost due to the small number of cylinders employed.

Another object is the elimination of drying between impressions.

A further object is the provision of a press in which smudging of the sheet by partial accidental contact of a surface thereof with an inked blanket cylinder prior to the printing of that surface by the cylinder, is avoided.

Still another object is the provision of a press of the character stated with the parts so disposed as to afford convenient operation and servicing.

Another object is the provision of a press of this character wherein the inkers are disposed above the plate cylinders in the most approved relation of those parts of a press.

A general object is the provision of a press which shall be capable of producing printing of high quality.

Other objects and features of novelty will appear as we proceed with the description of those embodiments of the invention which, for the purposes of the present application, we have illustrated in the accompanying drawings, in which Fig. l is a diagrammatic elevational view, partly in vertical section, of a printing press embodying the invention, including sheet feeding and sheet delivery mechanisms.

Fig. 2 is a similar view of a modified construction in which blanket cylinders of double size are employed.

Fig. 3 is a view similar to Fig. 2 on asmaller scale with provision for feeding the sheets downwardly instead of upwardly between the two blanket cylinders, and

Fig. 4 is a detail view illustrating a means for preventing accidental contact of sheets with the inked blankets before the impression line is reached.

Referring first to Fig. l, 6 illustrates a bank feeder for transmitting sheets in succession along a feed board I either singly or in lapped relation, as shown, to a set of feed rolls 8. Any other means for advancing sheets to these rolls could be employgd, as the feeder per se forms no part of the present invention. Preferably the feeder, including the feed board, is mounted upon movable frames 9 carrying rollers l running on tracks ll so as to permit the feeder to be retracted a desired distance, as indicated in dotted lines, to permit operat ons to be more readily performed on the cylinders and other parts of the press. I2 is a continuously rotating feed cylinder which takes sheets advanced by the rollers 8 at a speed lightly greater than the surface speed of the cylinder and grips them by grippers l3 while they are front registered against stops on the cylinder. Mechanism of this type is disclosed more or less in detail in Patent No. 1,307,969 to A. F. Harris dated June 24, 1919. However any other suitable means for presenting sheets to the grippers l3 may be substituted for that just described without departing from the spirit of the invention.

Each sheet, after it is registered and taken by the grippers I3, is advanced to the nearest point adjacent a blanket cylinder I4, is released by those grippers and taken by grippers IS on the blanket cylinder l4. I6 is another blanket cylinder disposed alongside cylinder l4 and in impression relationship therewith to form a printing couple for printing on both sides of a sheet simultaneously. In the form illustrated there are no grippers on cylinder I6. Plate cylinders l1 and I8 are arranged in operative relatio to blanket cylinders l4 and [6 respectively, being disposed above the axes of the latter cylinders but laterally thereof in order to provide a considerable space between the plate cylinders for a purpose presently to appear. Above each of the plate cylinders I! and I8 there is an inking mechanism, the parts of which may be referred to collectively as I9 and 20 respectively. Dampening equipment, such as is required when lithographic plates are employed om cylinders l1 and I8 is indicated at 2| and 22.

In the space between plate cylinders l1 and [8 we mount a stripper cylinder 23 having grippers 24 adapted to take the forward edge of each sheet from the grippers l5 and carry it upwardly to a point where it is taken by one of a plurality of sets of travelling grippers 25 on a chain conveyor 26 which conveys the sheets over the inking and dampening mechanisms 20, 22 and over a working space to piling mechanism of conventional form. The spacing apart of the plate cylinders I1 and I8 and of the inking mechanisms l9 and 20 leaves a clear space for the conveyor chains 26 and sprockets 21 as well as for the cylinder 23.

We have illustrated two modes of handling the sheets prior to the time they pass through the impression line between the blanket cylinders l4, It. In the preferred form, cylinder l2 not only acts as a means for feeding the sheets to the grippers of cylinder 4 but also acts as an impression cylinder for pressing the sheets against the blanket cylinder M. For this purpose, cylinder I2 is appropriately constructed to provide a continuous impression surface of proper radius as shown in Figure l. The action of this cylinder is to press the sheet against the blanket cylinder |4 so as to be printed by the latter and so as to be caused to adhere thereto during travel'of the sheet from cylinder l2 to the impression line between cylinders l4 and i6. The'adherence of the sheet to the blanket cylinder I4 is effected partly by the stickiness of the ink on the blanket, and partly by the substantial absence of air beneath the sheet and atmospheric pressure on the outside of the sheet. and these effects may be assisted if desired by the use of brushes 28 arranged to press against the sheet and hold it in contact with cylinder M.

In the above described form, the sheet is twice pressed against the blanket cylinder l4, once as it passes impression cylinder l2 and again as it passes blanket cylinder I6. The effect, however, is that of a single printing only, since the sheet does not change its position on cylinder M between impressions. The amount of pressure exerted by cylinder |2 may be equal to that ordinarily required for a full imprint, or if desired, it may be less than that amount so as to produce only a partial or faint imprint, the pressure exerted by cylinder l6 completing the imprinting; but in any case, in this form of the invention, cylinder i2 so cooperates with cylinder l4 when placing a sheet thereon as to effectively iron out the sheet against that. cylinder in a manner to enable it to be held there without harmful movement until it reaches the impression line between cylinders l4 and I6. In this manner smudging of the sheen is avoided.

In the second mode of handling the sheets, as illustrated in Figure 4, we provide different means for preventing smudging of the work. In this case, sheet S is taken from the feed board by a rotary gripper device 30 of known construction and advanced to the grippers 3| and cooperating pads 3| of a continuously rotating transfer cylinder 32. From these grippers it is transferred togrippers 33 on the blanket cylinder I4 and thereby drawn around that cylinder in an upward direction past the printing line between that cylinder and blanket cylinder l6, after which it may be taken by a stripping cylinder similar to cylinder 23 of Fig. 1. The body of feed cylinder 32 is depressed radially below the level of gripper pad 3| so that the sheet S" can travel over cylinder 32 without touching cylinder M. A guard 34, consisting preferably of a series of narrow fingers spaced transversely of the machine, is disposed to prevent any part of the sheet S from swinging far enough away from cylinder l4 to contact cylinder l6 and become smudged by the ink image on that cylinder. To prevent the sheet from contacting cylinder l4 ahead of the line of impression between the two cylinders, a series of transversely spaced air nozzles 35 is caused to inject a layer of air under pressure between the sheet and the cylinder l4. Alternatively, suction devices may be placed in the position occupied by fingers 34 and operated to draw the sheet toward them and away from cylinder H.

The form of the invention illustrated in Fig. 2 is like that of Fig. 1 in major respects. However its two blanket cylinders 40 and 4|, instead of being of the same diameter as the feed cylinders and the plate cylinders, are double size. and each of them is equipped with two blankets 42, 43 in the one case and 44, in the other. The same ink image is transferred to each of the blankets 42 and 43 by a plate cylinder 46, and another ink image is transferred to each of the blankets 44 and 45 by a plate cylinder 41, the plate cylinders 46 and 41 being inked by mechanisms 43 and 43 respectively and dampened by dampening devices 48' and 49' respectively. An advantage of the double size blanket cylinders lies in the greater accessibility of those cylinders. Another advantage is the greater space available for other parts ofthe press such as the delivery mechanism.

A sheet of paper S is taken from a feed board 50, forced against front stops on a continuously rotating combination feed and impression cylinder 5|, gripped by sheet grippers 52 thereon and transferred to grippers 53 on cylinder 40 at the front end of blanket 42. The forward edge of the sheet is then carried along the periphery of the cylinder 45 in a clockwise direction and upwardly through the impression line between the two cylinders 40 and 4|. The sheet preceding sheet S is shown at S under the grip of sheet grippers 54. The sheet S received an imprint, either complete or faint, as it moved between cylinder 5| and blanket 43, but as it moves through the line of contact between'the two cylinders 40 and 4| it receives a full imprint on both sides. The blankets 43 and 44 cooperate to perfect alternate sheets and the blankets 42 and 45 cooperate to perfect the other alternate sheets. When the sheets have been printed they are transferred from grippers 53 or 54, as the case may be, to grippers 55 on a stripper cylinder 56 v which then transfers them to one of a plurality of sets of grippers 51 on a chain conveyor 58 constituting part of'a delivery mechanism which includes sprocket'wheels 59.

In Figs. 1, 2 and 4 the design and arrangement of the machine is such as to cause the sheets to travel upwardly between the blanket cylinders.

- The invention also contemplates a reversed arrangement wherein the sheets travel downwardly between a pair of blanket cylinders. A construction of this kind is illustrated in Fig. 3, wherein double blanket cylinders 66 and 6|, similar to cylinders 40 and 4|, are shown. The blankets on these cylinders receive ink images from plate cylinders 62 and 63 to which ink is applied by inking mechanisms 64 and 65 and dampening material is applied by dampening mechanism 64 and 65. The sheets are caused to travel down a feed board 66. At the front end of the latter they are gripped by feed rolls 61 and pushed against front stops on a continuously rotating feed cylinder 63 from which they are transferred to a second feed cylinder 69 that occupies a position such that it is adapted to transmit sheets in the proper direction to grippers 10 or 1| as the case may be, on blanket cylinder 60. Cylinder 63' may be merely a feed cylinder similar to cylinder 32 of Fig. 4 and means similar to air nozzles 35 andfingers 34 may be provided for holding the sheet away from cylinder 66 prior to its arrival at the printing line between cylinders and 6|, but preferably, and as shown, cylinder 63 is constructed and disposed toact also as an impression cylinder similar to cylinders I2 and 5| of Figs. 1

and 2. After the sheet is taken by grippers III or 1| it is then caused to pass downwardly between cylinders 60 and 6| and to be imprinted on both sides by the images carried by the blankets on those cylinders. After the forward edge of each sheet passes downwardly through the printing line, it is stripped from cylinder 60, as by a stripper cylinder 12, and then passed to a cylinder 73 from which it is transmitted to grippers on a chain conveyor 14 constituting part of a delivery mechanism. It is apparent that the arrangement just described enables operations to be performed on the in-running side of each pair of plate and blanket cylinders and provides for location of the cylinders such that the blanket cylinders may readily be moved out of contact with each other, with their plate cylinders and with the feed impression cylinder, when the impression is tripped.

It is obvious that either of the two cooperating blanket cylinders may be provided with grippers and the sheets fed to those grippers by an appropriate arrangement of the feed cylinder; or both blanket cylinders may be provided with grippers and the sheets transferred from the grippers on one such cylinder to those on the other, from which they may be taken by a suitable stripping cylinder. Other variations may be made within the spirit of the invention.

The mode of operation of the constructions above described will be evident to those skilled in the art, it is believed, without further explanaion.

Having thus described our invention, we claim: 1. In a perfecting ofiset press, two blanket cylinders disposed side by side in impression relation to each other, sheet grippers on at least one of said blanket cylinders, plate cylinders disposed above the axes of said blanket cylinders, inking mechanism disposed aboveeach of said plate cylinders, a stripper cylinder disposed above said blanket cylinders between said plate cylinders adapted to take sheets from a gripper equipped blanket cylinder, a feeding cylinder for feeding sheets to a gripper equipped blanket cylinder at a point below the axis thereof, and means for holding the sheet away from the other blanket cylinder until the impression line between blanket cylinders is reached.

2. In a perfecting offset press, two blanket cylinders disposed side by side in impression relation to each other, sheet grippers on at least one of said blanket cylinders, plate cylinders disposed above the axes of said blanket cylinders, a stripper cylinder disposed above said blanket cylinders between said plate cylinders adapted to take sheets from the said gripper equipped blanket cylinder, a feed cylinder for feeding sheets to the said gripper equipped blanket cylinder at a point below the axis thereof, means for holding the sheet behind its gripped edge away from the latter cylinder, and means for holding it away from the other blanket cylinder until the impression line between blanket cylinders is reached.

3. In a. perfecting offset press, two blanket cylinders disposed side by side in impression relation to each other, sheet grippers on at least one of said blanket cylinders, plate cylinders disposed above the axes of said blanket cylinders, a

ing air from between the sheets and that cylinder.

4. In a perfecting offset press, two blanket cylinders disposed in impression relation with each other, a plate cylinder in operative contact with each of said blanket cylinders, sheet gripper means, including grippers on at least one of said blanket cylinders, adapted to convey the leading edges of sheets through the impression line between said blanket cylinders, a feed impression cylinder having grippers thereon adapted to transmit sheets to the grippers on one of said lanket cylinders and to press the sheets against the latter blanket cylinder and squeeze the air from between the sheets and that cylinder, means for presenting sheets to the grippers on said feed impression cylinder, and delivery meansarranged to take sheets from said sheet gripper means after their leading edges have passed through said impression line.

5. In a sheet-fed perfecting offset press, in combination, a pair of cooperating blanket cylinders arranged in impression relation with each other and adapted to print on opposite sides of sheets passing between them, a plate cylinder in operative contact with each of said blanket cylinders, sheet grippers on one of said blanket cylinders, and a feed-impression cylinder arranged to transfer sheets to said latter blanket cylinder and to squeeze the air from between the sheets and that cylinder prior to their passage between said blanket cylinders. x

6. In a sheet fed perfecting offset press, two blanket cylinders disposed side by side in impression relation, two plate cylinders wholly dis posed on the same side of the plane containing the blanket cylinder axes and spaced apart a distance greater than the diameter of one of them, inking mechanism for each plate cylinder also disposed on the same side of said plane as said plate cylinders, sheet grippers on at least one of said blanket cylinders, a sheet handling cylinder on one side of said plane having sheet grippers to feed sheets to the grippers of said blanket cylinder and disposed in pressure relation thereto, and a sheet handling cylinder on the other sideofsaid plane having sheet grippers cooperating with said sheet grippers on said blanket cylinder to take sheets therefrom, one of REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,022,406 Coy Apr. 9, 1912 1,282,642 Scott Oct. 22, 1918 1,358,843 Grass Nov. 16,1920 1,459,312 Pritchard June 19. 1923 1,916,454 Wohlrabe July 4, 1933 2,360,340 Harris Oct. 17, 1944 FOREIGN PATENTS Number Country Date 1,841 Great Britain Dec. 10, 1914 380,758 Germany Sept. 11, 1923 226,816 Great Britain May 7, 1925 541,102 France July 22, 1922