US2859691A

US2859691A - Web printing presses

Info

Publication number: US2859691A
Application number: US709567A
Authority: US
Inventors: Heller Franz
Original assignee: American Type Founders Co Inc
Current assignee: American Type Founders Co Inc
Priority date: 1958-01-17
Filing date: 1958-01-17
Publication date: 1958-11-11
Anticipated expiration: 1975-11-11
Also published as: CH363359A

Description

NOV. 11, 1958 HELLER 2,859,691

WEB PRINTING PRESSES Filed Jan. 17, 1958 v k 2 Sheets-Sheet 1 v *1 x f i A; J #G CJI.)

ATTORNEYS NOV. 11, 1958 r HELLER 2,859,691

WEB PRINTING PRESSES Filed Jan. 17, 1958 I 2 Sheets-Sheet 2 INVENTOR BY #:flou (M M9 9% ATTORNEY United States Patent WEB PRINTING PRESSES Franz Heller,Mount Vernon, N. Y., assignor to American 'Type'Founders Co., Inc, Elizabeth, N. 5., a corporm tion of Delaware Application January 17, 1958, Serial No. 709,567

5 Claims. (Cl. 101-177) This invention relates to printing presses and more particularly to multiple unit oifset perfecting web presses,

and it has for its general object the provision of novel and improved means for maintaining control of the web between the units of these presses in order to insure with one color. Each unit comprises two blanket cylinders, each having a plate cylinder running in contact therewith. Each blanket cylinder of a printing unit serves as an impression cylinder for the other blanket cylinder. Now a blanket cylinder in presses of this type is provided with a gap (perhaps in the neighborhood of fiveeighths of an inch wide) in which the clamping mechanism for the ends of the blanket is located. The two cylinders of a given pair are so timed that the gaps come into registry upon eachrevolution. This means that the web passing through the unit is not under the proper gripping pressure between the cylinders at this moment and it is possible for the webto move or slip relatively to the printing couple and as a consequence it may become out of register with the impression at the next unit.

This condition is particularly noticeable in the case of cylinders of smaller diameters, and in two unit presses and in presses of four or more units in which only two units are being used for printing. In such cases the difiiculty is aggravated and there is a definite tendency for double printing or mis-register.

The applicant has discovered that the most effective way of overcoming this lack of control of the web when the gaps come together is to cause the web to wrap slightly around both of the blanket cylinders instead of passing through the printing couple in absolute tangency with the cylinders. In this way the web is still in contact with the blanket portion of the cylinders through a slight are even though it spans the gaps. v The invention, therefore, in its preferred embodiment,

contemplates the provision in a multiple unit web perfect ing press, of oifsetprinting couples consisting-of pairs of blanket cylinders, each running in contact with a plate cylinder or other type of cylinder adapted to transfer an ink image to the blanket cylinder. The plate cylinders of each unit are maintained in their usual or conventional positions with their axes preferably in vertical alignment and spaced apart the usual distance to accommodate the rolling contact of the respective blanket cylinders with the plate cylinders and with each other. However, instead of disposing the blanket cylinders also in vertical alignment with each other, they are each angularly shifted about the axes of their associated plate cylinders as centers, always in impression contact but so that a straight line through the centers of the blanket cylinders and their point of tangency is inclined to the vertical. Thus the web cannot pass directly between the blanket cylinders in a horizontal plane and in line tangency with the blanket cylinders, as in the usualpractice, but must be diverted in a very slight S-shaped pattern whereby there is a limited wrap-around of the web with a short portion of the periphery of each of the blanket cylinders.

This modification, while. being of a simple nature and requiring a minimum of alteration in press structure and adjustment, yields anunexpected and extremely significant and valuable improvement in operation of this particular type of multiple unit offset perfecting printing press operation, where even the slightest misalignment or-non-register ofsuccessive portions of the printed image, results in impairment or spoilage of the product.

One particular value in the present invention is. the attainment of such insurance against non-register ,,without disturbing the installation of the plate cylinders and their inking mechanisms nor the addition of supplemental equipment to the press, butmerely the complementary rotation of the axes of the blanket cylinders around their respective plate cylinders. e

Other objects and features of novelty will be apparent from the following specification when read in connection with the accompanying drawings in which one embodiment of the invention is illustrated by way of example.

l-In the drawings;

; Figure 1 is a somewhat diagrammatic view in side elevation ofa two unit offset perfecting web press embody- 'ing the principles of thepresent invention; Figur'eZ is a diagram showing one adaptation of the invention which afford adequate wrap-around for accomplishin'g the purposes described;

Figure 3 is a considerably enlarged vertical sectional view through the contacting blanket cylinders of the offset perfecting press to which the invention has been applied;

and

Figure 4 is a diagram similar to Figure 2 showing a modification of the invention which is less preferred than the principal embodiment.

In Figure 1 of the drawings there is shown in quite diagrammatic form a web press of the oifset perfecting type, and thisillustration may well represent in its entirety a twounit press, or two adjacent units of a four unit I press of the general type now in wide use;

The press is designated generally by the reference numeral 10,, the first unit being shown at 11 and the second 'unit designated 12. These units are supported and surrounded by the usual framework appurtenant to large presses of this type, which framework may be given the general designation 13. v

From the web roll and the preliminary feed rolls usually employed in connection with such presses, the web 20 is guided to the first unit 11 and passes in impression relation between the

blanket cylinders

25 and 26, the upper blanket cylinder 25 being supplied with an inked image of the text composition, illustrations, or other impressionto be printed, by means of the plate cylinder 27, and the lower blanket cylinder 26 being similarly impressed from the plate cylinder 28.

The second printing unit 12 is provided with an identical printing couple and the various parts have been given the same, reference numerals. The web 20 after having received the impressions upon both sides in the units 11 and 12 passes outof this portion of the press at the right-hand side thereofas indicated.

' In offset perfecting presses of this type, the .web, as readily understood, passes between the two

blanket cylf inders

25 and 26 of both-units and receives an impression on both sides from the inkedimages on both ofthe blanket cylinders. In such casejof course, each blanket cylinder acts as an impression cylinder for the other one of the couple. Since this type of press is employed gener allyformulticolor work, .the importanceof .perfectregister of impressions from theblanket cylinders of the successive units cannot be exaggerated. Such misalignment or displacement of the web is most apt to occur when the gaps in the blankets of both cylinders at the points where they are secured coincide, and the web passes beween the blanket cylinders in perfect tangential relationship. The manner in which the present invention insures against this difiiculty will be understood as the description proceeds.

Referring now more particularly to Figure 3 of the drawings, it will be seen that the upper impression cylinders 25 are each provided with a blanket 40, the respective opposite ends of which are clamped between pairs of bars as at 41 and 42, one of the sets of clamping bars (41) being received within an indentation 43 in one wall of the recess 45 formed in the structure of the cylinder 25.

Similarly received within the recess 45 is the block 46 secured by means of the bolt 47. Within a semi-cylindrical indentation in the block 46 is received an adjustable cylindrical clamping element 50 which is adapted to grip the clamped end structure 42 of the blanket 40 and apply tension to the blanket to cause it to adhere snugly to the surface of the cylinder 25.

It will be readily seen that the blanket clamping devices in these usual constructions leave a gap which is indicated at 60 where the end portions of the blanket 40 leave the cylindrical surface of the rolls 25 and enter the recess 45.

It will be noticed from an inspection of Figure 3 that the lower blanket cylinder 26 is provided with the blanket clamping devices which are the mirrored counterpart of those described in connection with the upper cylinders and the various parts are therefore given the same reference numerals.

The fastening provisions for the blankets of the lower cylinders 26 also leave a similar gap 60 which, when the cylinders are set for proper operative registry, coincide once each revolution and provide a space, of more or less longitudinal extent, along the web where the web would be momentarily free of clamping support between the cylinders; and unless specific provisions are made, the web would be subject to displacement which would destroy the registry and cause double printing.

In order to prevent this eventuality and insure that the web is in firm rolling contact with the blanket cylinders for an adequate arcuate extent to prevent any inadvertent slippage, the upper blanket cylinders 25 are displaced around the center of their associated plate cylinders 27 in a clockwise direction and the lower blanket cylinders 26 are similarly displaced around the centers of their plate cylinders '28 also in a clockwise direction, as depicted in Figures'l, 2, and 3 of the drawings.

'The result of this angular complementary displacement of the blanket cylinders is clearly apparent from an inspection of Figure 3 of the drawings where the cylinders are shown on an enlarged scale. It will be readily perceived that the web pursues a zig-zag or somewhat S-shaped course through the bight of the printing couple and the web is therefore in wrap-around contact with one and then the other of the blanket cylinders through a distance from the point 61 to the point 62 and this is adequate to afford suflicient frictional contact to prevent any slippage between the web and the blanket cylinders. It will be quite obvious that this arrangement prevails in both units 11 and 12 and thus the web is always in secure frictional contact with the blanket cylinders of both units of the press.

In Figure 2 of the drawings one example of the eifectuation of these purposes is shown merely by way of illustration, the angular displacements of the cylinders n th s examp e affording qui adeq te wrap-a und for the purpose. In some instances somewhat less displacementrnight sutficqandif it is found necessary an additional displacement of the cylinders might be adopted.

In the example chosen for illustration, the blanket and plate cylinders are all of a diameter of about 7%" and the center-to-center vertical distance AB between the

plate cylinders

27 and 28 is approximately 19". The center C of the upper blanket cylinder 25 is swung around the point A as a center, in a clockwise direction, until the angle BAC is approximately 25. Similarly, the center D of the lower blanket cylinder 26 is moved clockwise around the center B of the corresponding plate cylinder until the angle ABD is approximately 42. The blanket cylinders C and D will, under these conditions, be in impression contact, but the line CD connecting their centers will make an angle of approximately 14 with the vertical line CE. It works out that with the line joining the line CD joining the centers of the blanket cylinders making an angle of 14 with the vertical, the length of wrap-around contact of the web 20 with the blanket cylinders and represented by the distance 6162, will be in the neighborhood of 1% and this will suffice to afford the necessary frictional contact for insuring registry of images.

In Figure 4 of the drawings there is diagrammatically illustrated another embodiment of the invention which is not as practical as the one already described but which nevertheless comes within the broader generic aspects of the conception.

In this case, as in the other embodiment, the

plate cyl inders

27 and 28 are in vertical alignment and the upper blanket cylinder 25' associated with the plate cylinder 27 is swung still further in a clockwise direction about the center A of the upper plate cylinder.

In this specific embodiment where the diameters of the cylinders are taken to be about 7%", the angle B'AC' will be in the neighborhood of 20".

However, the lower blanket cylinder 26 associated with the plate cylinder 28 is shifted to a considerable approximately 20 the same as the angle BA'C', while the line CD' joining the centers of the blanket cylinders which form the oifset perfecting printing couple will extend at an approximate angle of 45 with the horizontal and vertical.

It will be seen that in this arrangement the web 20 will pass between the blanket cylinders 25',and 26' with considerable wraparound from the point 61 to the point 62', totalling in this specific illustrative arrangement a little over 5 /2". This is quite a bit more than is necessary and there are certain drawbacks to this arrangement which are not present in the embodiment first described. For example, this arrangement would require changing many other components of the press, as compared with the one first described, and also, access to the lower blanket cylinder would be very considerably restricted since the operator must work from the right-hand side of the press unit in handling and servicing the blanket cylinders.

It will be seen from the foregoing specification that there has been provided by the present invention novel and quite useful arrangements of offset perfecting blanket cylinders which insures perfect register especially in a multi-unit press of the type described.

It is understood that various changes and modifications may be made in the embodiments illustrated and described herein without departing from the scope of the invention as defined in the following claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In an ofiset perfecting web printing press or the like. in combination, two spaced printing unitseach including a pair of blanket cylinders; plate cylinders supported in the press for rolling contact with the respective blanket cylinders for applying inked images thereto; means supporting said blanket cylinders for rolling contact with the respective opposite surfaces of a web passing between them, thus providing an offset perfecting printing couple in which each blanket cylinder acts as an impression cylinder for the other one, as well as an offset printing cylinder; a gap in the periphery of each of said blanket cylinders as where the blanket ends securing means are, disposed, the registry of the two blanket cylinders of each unit being such that the two gaps coincide upon opposite sides of the web at one point during each rotation; means for supporting and feeding a web of material to be printed, in a direction approximately perpendicular to a plane containing the axes of both of the plate cylinders of each of said units, the distance between the mutually facing surfaces of said plate cylinders being shorter than the sum of the diameters of the two blanket cylinders, whereby the two blanket cylinders in order to be in rolling contact with each other and in individual rolling contact with their respective plate cylinders must have their centers displaced laterally from the common plane of the axes of the plate cylinders,the amount and direction of displacement of said blanket cylinders being such that the common plane of tangency of the blanket cylinders intersects the axis plane of the plate cylinders at an acute angle, and thus whereby said web is diverted from its normal horizontal path and its area of contact with said blanket cylinders is increased and maintained during the passage of said gaps in said blanket cylinders.

2. The offset perfecting web printing press as set forth in claim 1 in which thecommon plane containing the axes of the two blanket cylinders makes an angle of from about 14 to about 45 with the common plane containing the axes of the two plate cylinders.

3. The offset perfecting web printing press as set forth in claim l'in which the axes of said blanket cylinders are disposed upon opposite sides of the common axis plane of the plate cylinders, and the angular displacement of the two blanket cylinders from said plate cylinder axis plane and about the axes of their respective plate cylinders as centers is therefore equal.

4. In an offset perfecting web printing press or the like, in combination, two spaced printing units each including a pair of blanket cylinders; plate cylinders supported in the press for rolling contact with the respective blanket cylinders for applying inked images thereto; means suporting said blanket cylinders for rolling con tact with the respective opposite surfaces of a web passing between them, thus providing an offset perfecting printing couple in which each blanket cylinder acts as an impression cylinder for the other one, as well as an offset printing cylinder; a gap in the periphery of each of said blanket cylinders as where the blanket ends securing means are disposed, the registry of the two blanket cylinders of each unit being such that the two gaps coincide upon opposite sides of the web at one point during each rotation; means for suporting and feeding a web of material to be printed, in a direction approximately perpendicular to a plane containing the axes of both of the plate cylinders of each of said units, the distance between the mutually facing surfaces of said plate cylinders being shorter than the sum of the diameters of the two blanket cylinders, whereby the two blanket cylinders in order to be in rolling contact with each other and in individual rolling contact with their respective plate cylinders must have their centers displaced laterally from the common plane of the axes of the plate cylinders, the axes of the blanket cylinders being disposed upon the same side of the common axis plane of the plate cylinders and the angular displacement of the two blanket cylinders about the axes of their respective plate cylinders from said plate cylinder axis plane being unequal so that the common plane of tangency of the blanket cylinders intersects the axis plane of the plate cylinders at an acute angle, and thus whereby said web is diverted from its normal horizontal path and its area of contact with said blanket cylinders is increased and maintained during the passage of said gaps in said blanket cylinders.

5. The oifset perfecting web printing press as set forth in claim 4 in which the common plane containing the axes of the two blanket cylinders makes an angle of approximately 14 with the common plane containing the axes of the two plate cylinders.

References Cited in the file of this patent UNITED STATES PATENTS