US2794390A - Stock feeding means for rotary printing machine - Google Patents

Description

June 4, 1957 J. A. BURKE, JR 2,794,390

STOCK FEEDING MEANS FOR ROTARY PRINTING MACHINE Filed March 20, 1953 INVENTOR ATTORNEYS United This invention relates to methods and means for printmg and, more particularly, to such methods and means for printing on a multiply surface such as the back of an envelope.

Printing across the entire rear face of envelopes has become increasingly popular during recent years. The problems attending printing across an entire surface comprising a plurality of flaps which present an uneven surface have been solved, at least in part, by using a relatively soft blanket on the printing cylinder so that the impression may be made completely up to the shoulders presented by overlying flaps, and there will be no unprinted portions of the surface. To print over an entire surface, however, it is necessary to dispense with the usual grippers which, on conventional presses, engage the leading edge of a sheet to be printed and hold it for proper registration as it is drawn between the printing and pressure cylinders. The conventional use of pairs of grippers is not feasible even where a narrow border around the periphery of the sheet is to be left unprinted. The conventional gripping means are too large for this purpose. Printing without grippers has presented many problems with regard to proper registration of the sheet to be printed. A further problem has confronted those who have attempted to print without grippers. it is well known that material to be printed has a tendency to wrap around the printing roll, and the grippers have served the purpose of stripping the sheet from the roll. Consequently, when grippers are dispensed with the stripping problem is present.

The object of the present invention is to provide methods and means for securing accurate registration of the sheet to be printed without the need for gripping the sheet between pairs of jaws, and for maintaining that registration throughout the printing cycle.

A further object is to provide means to align the sheet before the sheet reaches the nip of the printing and pressure cylinders, and to hold that alignment during the passage of the sheet between these rolls.

A still further object of the invention is to provide means for stripping the sheet from the printing roll without the need for gripping elements.

Other objects of the invention will appear from the following description of practical embodiments thereof when taken in conjunction with the drawings which accompany, and forma part of, this specification.

' In the drawings:

Fig. l is a somewhat schematic View of the feed rolls, printing and impression rolls, and paper guide chain of an offset press embodying the principles of the present invention;

Fig. 2 is a vertical transverse section through the structure shown in Fig. 1, and is taken on the line 22 of Fig. 1;

'Fig. 3 is a View similar to Fig. 1 showing a modified form of the means for controlling the stock in its passage through the machine; Fig. 4 isan enlarged, vertical sectional view of portions of the printing and pressure rolls and the stock guide atent chain just prior to the sheet reaching the nip of'the rolls;

- vention, no showing'has been made of an entire printing press, and those portions of the machine which are shown are illustrated more or less schematically.

in general, the invention consists in feeding the leading edges ofa sheet of desired stock against a travelling aligning means and maintaining the sheet in contact with the aligning means during its entire passage between the printing and pressure cylinders. It further consists in a machine for carrying out this method, and in the provision of aligning means which will also serve to strip the stock from the printing cylinder.

Referring to'the drawings in detail, and first adverting to that form of the invention shown in Figs. 1 and 2, there is shown a conventional pressure cylinder I mounted upon a shaft 2, which shaft is to be journalled in the usual frame (not shown) and driven by conventional means to rotate the cylinder. Directly beneath the pressure cylinder there is a printing cylinder 3 mounted upon a shaft 4, also suitably journalled and driven. The printing cylinder is provided with a relatively thick blanket 5 of soft material such as rubber, which takes the image from the usual plate (not shown) for transfer to the stock. The printing and pressure cylinders are mounted in the usual manner so that the periphery of the pressure roll is in contact with the blanket 5 on the printing cylinder duringthat portion of the rotation of the cylinders when the blanket is passing beneath the pressure cylinder.

In front of the cylinders 1 and 3 are a pairof feed rollers 6 and 7. These feed rollers are located in advance of the cylinders, but close enough so that the leading edge of the stock being fed will be gripped by the nip of the cylinders before the trailing edge is released from the nip of the feed rolls.

At either side of the printing cylinder guide chains 8 are arranged. The chains pass over sprockets 9 at the front, and sprockets 10 at the rear or delivery end of the machine. Sprockets 9 are mounted upon shaft 4, which carries the printing cylinder, and sprockets 10 are mounted upon a shaft 11. The sprockets are arranged so that the flights of the endless chain are inclined, and the top flight has its top surface substantially tangential to the cylinders 1 and 3 at the nip between the cylinders. v

There are two guide chains 8 which are spaced apart a distance slightly greater than the length of the pressure and printing cylinders. The chains carry a bar 12 which bridges the distance between the two chains and has its ends attached to the chains. The bar carries several .horizontally extending arms 13. These arms are spaced apart along the bar and each has a vertically positioned shoulder 14, which forms an abutment for the stock. As the shoulders are in alignment, they form guides to properly position the stock before its entry between the nip of the printing and pressure cylinders. The fingers have overlying forwardly extending portions which form horizontal stock-engaging surfaces 15 to hold the forward edge of the stock against the blanket 5 on the printing cylinder asthe stock enters the nip of the cylinders. The guide arms 13 also have upward extensions 16 which rise above the plane of the arms, for purposes to be described. The printing cylinder has a longitudinal groove 17 in-its periphery and the pressure cylinder .has a similar groove 18 to receive the bar and guide arms to permit them to pass the cylinders during rotation.

A plurality of recesses 19 are formed in the trailing edge of the groove 18 in cylinder 1, which recesses are also open to the surface of the roller. Recesses 19 receive the upward extensions 16 of the guide arms, and are dimensioned so as to be of approximately the same Width as the extensions 16. The depth of the recesses from the surface of the cylinder is exactly the depth of extensions 16 to the stock-engaging surfaces 15, so that when the extensions are in the recesses, the surfaces 15 are flush with the peripheral surface of the pressure cylinder.

As the bar 12 is connected to opposite links of the chain 8, the position of the bar and the guide. arms carried by the bar will always be tangential to the arcuate path of travel of the bar when passing around sprockets 9. As the operative end of the arms, having the shoulders this end of the arms will be spaced an appreciable distance outward from the orbit of the chain during the passage of the chain around the sprockets. Thus, as the 19 and the shoulders 14 willbridge the gap between the surface of the pressure cylinder .1 and the blanket carried on the printing cylinder. This is the position of the parts illustrated in Fig. 4 of the drawing. When'in this position the shoulders 14 will form stops to position the forward edge of the stock being fed to the cylinders which position the-leading edge of the printing blanket. As the cylinders continue their rotation and reach the point'of nip, the forward edge of the stock will be firmly placed against the blanket along its full length. The stockengaging surfaces 15 of the guide arms will substantially complete the surface of the pressure cylinder and as the extension 16 of the arms is against the top of the recess, equal pressure will be applied'along the full leading edge of the stock.

The stock is guided'in its passage into contact with the guide arms by means'of the usual guide 20 placed between feed rollers and the printing and pressure cyl- 'inders. As is customary, the feed rollers operate with a varying speed, and when stock passes between them their speed is increased so that the leading edge of the stock approaches and contacts the shoulders of the guide arms. As the stock is moving slightly faster than the speed of the guide arms 13, the stock will be pressed against the shoulders and held there until the stock is engaged between the nip of the cylinders. Due to the fact that the chains carrying the guide arms are moving at the speed of the printing and pressure cylinders and stock will be held in positive registration with these cylinders throughout the printing cycle, and due to the velocity of the stock upon leaving the cylinders, it will be maintained in engagement with the guide arms until the delivery end of the machine is reached.

In Figs. 3 and 4 of the drawings a slightly modified structure has been shown. In this form of the invention it is necessary that a strip of insulating material 21 be positioned between the guide fingers and the bar 12. In order to permit the guide arms to have a positive hold I on the stock, the guides are given a charge of static electricity before the stock is brought in contact with 'them. This will permit the guide arms to strip the stock from the printing cylinder and, therefore, allow the use of much heavier printing inks. To obtain the static charge, a piece of cats fur 22 may be positioned at any convenient'point on the machine so that it may be contacted by the upward extensions 16 on the guide arms.

The fur is shown as mounted beneath the bottom flight of the chain near the front of the-machine, so that the charge is given to the arms just prior to their engagement with the stock. As shown in Fig. 3, a tinsel ribbon 23 maybe used at the rear of the machine so that a guide arms will contact it in passing around the rear sprockets, to discharge the static charge and release the stock from the guide arms, so that it may drop into a basket or other alignment of the stock will be maintained throughout the 14 and stock-engaging surfaces 15, is beyond the bar, 1

1. Printing apparatus comprising a printing cylinder.

and a pressure cylinder, 'a blanket on said printing cylinder, said cylinders mounted for rotation so that the pressure cylinder will be in surface contact with said blanket once each cycle of rotation, feed rollers to. one side of said cylinders at a distance from said cylinders less than the length of thestock to be printed, chains at either side of said printing cylinder mounted upon sprockets concentric to said printing cylinders and sprockets to the opposite side of said cylinders from said feed rollers, a bar bridging said chains and carrying transversely aligned guide arms to be contacted by and align the stock, means to rotate said cylinders at the same surface speed and said chains at a linear speed equal to the surface speed of said cylinders, said cylinders having transverse grooves therein to permit passage of the said bar and fingers through the nip of the cylinders, said pressure cylinder having a plurality of recesses opening'to said groove and the surface of said pressure cylinder, said recesses being aligned with the path of travel of said guide arms, said arms having vertical shoulders to align said stock for registration with the printing cylinder blanket, horizontal overlying lips to than the length of the stock to be printed, a pair of endless chains one on either side of said printing couple, sprockets concentric to the printing cylinder and rotatable therewith and sprockets on the opposite side of said printing couple from said feed rollers, said chains passing around said sprockets, a bar positioned transversely of said chains and having its ends connected to one link in each chain, a plurality of arms spaced along said bar and extending rearwardly with respect to the direction of travel of said chains, each of said arms having a shoulder at right angles to the chain links to which said bar is attached positioned rearwardly of said links and in the projected plane of the leading edge of said blanket when said links are on the sprockets concentric to the printing cylinder and a lip extending rearwardly from said shoulder to lie tangentially to the surface of said blanket as said links leave the sprockets concentric to the printing cylinder, whereby said shoulders will form guide stops for stock at the leading edge of said blanket when said links are on the sprockets concentric to said printing cylinder and said overlying lips will press --the leading edge of stock into surface engagement with said blanket as said links leave said sprockets concentric to said pn'nting cylinder.

3. Printing apparatus comprising, a printing cylinder having a blanket thereon and a pressure cylinder arranged as a printing couple, a pair of feed rollers positioned in front of the nip of the printing couple a distance less than the length of the stock to be printed, a travelling guide movable in the direction of stock travel at the abutting surface, said guide and said printing couple having their respective movements timed to bring the abutting surface of said guide into alignment with the leading edge of the blanket on said printing cylinder prior to said leading edge reaching the nip of said printing couple, means carried by said guide to overlie the leading edge of the upper surface of stock against said abutting surface and on said blanket, and means on said printing couple to press said stock overlying means against the upper surface of said stock, said guide being mounted between a pair of endless chains passing around front and rear sprockets, said front sprockets being positioned concentric to said printing cylinder, and said rear sprockets positioned on the opposite side of said printing couple from said feed rollers.

4. Printing apparatus comprising, a printing cylinder having a blanket thereon and a pressure cylinder arranged as a printing couple, a pair of feed rollers positioned in front of the nip of the printing couple a distance less than the length of the stock to be printed, a travelling guide movable in the direction of stock travel at the surface speed of said printing couple and having a stock abutting surface, said guide and said printing couple having their respective movements timed to bring the abutting surface of said guide into alignment with the leading edge of the blanket on said printing cylinder prior to said leading edge reaching the nip of said printing couple, means carried by said guide to overlie the leading edge of the upper surface of stock against said abutting surface and on said blanket, and means on said printing couple to press said stock overlying means against the upper surface of said stock, said guide being mounted between a pair of endless chains passing around front and rear sprockets, said front sprockets being positioned concentric to said printing cylinder, and said rear sprockets positioned on the opposite side of said printing couple from said feed rollers, said guide comprising a bar bridging said chains and a plurality of guide arms positioned in alignment on said bar.

5. Printing apparatus comprising, a printing cylinder having a blanket thereon and a pressure cylinder arranged as a printing couple, a pair of feed rollers positioned in front of the nip of the printing couple a distance less than the length of the stock to be printed, a travelling guide movable in the direction of stock travel at the surface speed of said printing couple and having a stock abutting surface, said guide and said printing couple having their respective movements timed to bring the abutting surface of said guide into alignment with the leading edge of the blanket on said printing cylinder prior to said leading edge reaching the nip of said printing couple, means carried by said guide to overlie the leading edge of the upper surface of stock against said abutting surface and on said blanket, and means on said printing couple to press said stock overlying means against the upper surface of said stock, said guide being mounted between a pair of endless chains passing around front and rear sprockets, said front sprockets being positioned concentric to said printing cylinder, and said rear sprockets positioned on the opposite side of said printing couple from said feed rollers, and means to impart a static charge to said guide prior to the engagement of the stock therewith.

6. Printing apparatus comprising, a printing cylinder having a blanket thereon and a pressure cylinder arranged as a printing couple, a pair of feed rollers positioned in front of the nip of the printing couple a distance less than the length of the stock to be printed, a travelling guide movable in the direction of stock travel at the surface speed of said printing couple and having a stock abutting surface, said guide and said printing couple having their respective movements timed to bring the abutting surface of said guide into alignment with the leading edge of the blanket on said printing cylinder prior to said leading edge reaching the nip of said printing couple, means carried by said guide to overlie the leading edge of the upper surface of stock against said abutting surface and on said blanket, and means on said printing couple to press said stock overlying means against the upper surface of said stock, said guide being mounted between a pair of endless chains passing around front and rear sprockets, said front sprockets being positioned concentric to said printing cylinder, and said rear sprockets positioned on the opposite side of said printing couple from said feed rollers, said guide comprising a bar and a plurality of arms projecting therefrom, each of said arms having said stock abutting and stock overlying surfaces, and means to impart a static charge to said guide prior to the engagement of the stock therewith.

7. Printing apparatus comprising, a printing cylinder having a blanket thereon and a pressure cylinder arranged as a printing couple, a pair of feed rollers positioned in front of the nip of the printing couple a distance less than the length of the stock to be printed, a travelling guide movable in the direction of stock travel at the surface speed of said printing couple and having a stock abutting surface, said guide and said printing couple having their respective movements timed to bring the abutting surface of said guide into alignment with the leading edge of the blanket on said printing cylinder prior to said leading edge reaching the nip of said printing couple, means carried by said guide to overlie the leading edge of the upper surface of stock against said abutting surface and on said blanket, and means on said printing couple to press said stock overlying means against the upper surface of said stock, said guide being mounted between a pair of endless chains passing around front and rear sprockets, said front sprockets being positioned concentric to said printing cylinder, and said rear sprockets positioned on the opposite side of said printing couple from said feed rollers, said guide comprising a bar and a plurality of arms projecting therefrom, each of said arms having said stock abutting and stock overlying surfaces, and a piece of cats fur positioned to be contacted by said arms prior to engagement with said stock to impart a static charge to said arms.

8. Printing apparatus comprising, a printing cylinder having a blanket thereon and a pressure cylinder arranged as a printing couple, a pair of feed rollers positioned in front of the nip of the printing couple a distance less than the length of the stock to be printed, a travelling guide movable in the direction of stock travel at the surface speed of said printing couple and having a stock abutting surface, said guide and said printing couple having their respective movements timed to bring the abutting surface of said guide into alignment with the leading edge of the blanket on said printing cylinder prior to said leading edge reaching the nip of said printing couple, means carried by said guide to overlie the leading edge of the upper surface of stock against said abutting surface and on said blanket, and means on said printing couple to press said stock overlying means against the upper surface of said stock, said guide being mounted between a pair of endless chains passing around front and rear sprockets, said front sprockets being positioned concentric to said printing cylinder, and said rear sprockets positioned on the opposite side of said printing and pressure cylinders from said feed rollers, said guide comprising a bar and a plurality of arms projecting therefrom, each of said arms having said stock abutting and stock overlying surfaces, insulating material between said arms and said bar, and means to impart a static charge to said arms prior to the engagement of the stock therewith.

References Cited in the file of this patent UNITED STATES PATENTS 2,208,043 Ormond July 16, 1940 2,387,750 Davidson Oct. 30, 1945 2,406,205 Davidson et al. Aug. 20, 1946 2,576,882 Koole et a1 Nov. 27, 1951

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