US2896535A - Sheet-fed rotogravure machine for multi-colour printing - Google Patents

Description

July 28, 1959 Filed- June 2, 1955 HANS'BERNHARD SCHNEMANN SHEET-FED ROTOGRAVURE MACHINE FOR MULTI-COLOUR PRINTING 5 Sheets-Sheet l INVENT R HANS BERNHARD UNEM N ATTORNEY July 28, 1959 HANS-BERNHARD SCHNEMANN @5535 SHEET-FED ROTOGRAVURE MACHINE FOR MuLT1coLou-R PRINTING Filed June 2, 1955 l 3 SheecSSheet 2 lNVENTO F11 HANS BERN HARIQN ATTORNEY NIH July 28, 1959 HANS-BERNHARD SCHUNEMANN $395,535

SHEET-FED NOIOGRAVURE MACHINE FOR MULTI-COLOUR PRINTING Filed June 2, 1955 3 Sheetsneet 3 INVENTOR \,\l/ HANS EERNHARD SCHUNEQ: I

ATTORNEY 2,896,535 SHEET-FED RTGRAVURE MACHINE FR MUL'II-CLUUR PRINTING Hans-Bernhard Schiinemann, Wurzburg, Germany, as-

signor to Schneilpressenfabrik Koenig 8l Bauer Aktiengesellschaft, Wurzburg, Germany, a corporation of Germany ,Application .lune 2, 1955, Serial No. 512,699 6 Claims. (Cl. 101-152) The invention relates to a sheet-fed rotary press, especially to a sheet-fed multi-,colour rotogravure press.

Already known are sheet-fed multi-colour presses of standard unit design consisting of various printing units of similar design which are placed one behind the other and which are connected with each other by the usual sheet guiding devices, and where there is a transfer unit between each two printing units. Machines of this kind are quite suitable for multi-colour printing on a single page, they are, however, not suited for recto and verso printing.

There are also known printing machines of differing designs for multi-coloured printing on both sides of the sheet.

For example, it has been suggested to arrange several printing units of same design one on top of the other and to connect these with each other by means of transferdrums for the sheets. After leaving the upper printing units the sheets are conveyed, at unchanged running direction, over an additional turning-drum to the bottom printing units. Machines of this type have the drawback in that the colour combination that has been chosen, as for instance two colours recto and three colours verso (in future to be referred to as 2/ 3 colour print) is fixed for good. Employing the machine in a manner as it is possible with web-fed rotary presses (presses for printing on endless paper webs), it is impossible to print sheets with two colours n one side and three on the other side (hereafter referred to as 2/3 colour print) through a combination of four colours on one side and one on the other (hereafter referred to as 4/1 colour print) nor in the same machine is it possible to print a sheet with iive colours on a single side.

The desirability of switching over is achieved with another known machine in that the sheets are turned around by means of sheet turning devices which can be switched oif at will. The same is, however, accomplished by the invention under discussion. For example, a machine is known in the art which had three printing units which were arranged one on top of the other and fixed in a common side frame. With this machine, the sheet can after leaving the uppermost printing unit be transferred to a turning device that draws the sheet from the preceding feeding-table still more to the outside, thereafter depositing it on conveyor-belts which lead to the next feeding-table. This arrangement produced only a small hourly output. Furthermore, a subsequent extension of the machine was not permissible. Because of space considerations, its size was moreover limited to three printing units, i.e. to 3/0 and l/2.

Lastly, sheet-fed rotogravure presses with turning devices for obtaining any desired recto and verso combination are known which consist of several complete single colour machines that are arranged one behind the other in the so-called tandem fashion. These machines had to be suitable to be used individually as single colour machines for single-colour printing. Feeder and delivery piles could be bridged by tape-guidings which could be put in and out of action at will, and to which a turning device was added. With machines of this type a turning-device that can be switched on and oil was provided as a turning-chain, for example, it was not used when doing only recto printing. When the turning device was used it turned the sheet over and -delivered it to the conveyor-belts which can be partly swung oif and lead to the next feeding-table when doing verso printing. In conjunction with 4sheet guiding devices which 'could be partly swung off, the sheet turning devices caused an essentially choked running speed. As a matter of fact, no high-speed sheet-fed press for producing recto and verso printing as desired has been heard of as yet. Furthermore individual printing machines arranged in the tandem fashion occupy an extremely large length so that their use as a multi-colour machine consisting of many printing units cannot be considered.

All these dilhculties are now eliminated by the invention, in that the turning-device is fixed shortly before, i.e. a sheet length, the front lays of the feeding-table belonging to the latter, thus directly depositing the sheets on the feeding table of the next of the following printing units which are separated only by a transfer unit according to the standard unit system.

Upon being released by the turning-device the sheets are guided in the known manner on the conveyor-belts of the feeding-table. In this way it is not only possible to obtain the high output gained hitherto with single-side printing only but also when doing multi-colour recto and verso printing, but even increasing output essentially in spite of having to turn the sheets.

In further developing the invention, the separate sheets are deposited in an overlapping way on the conveyor-belts of the feeding-table by the turning-device itself, so that the sheets have a better guiding amongst each other and move towards the front-lay slowly.

A short transferring-chain with changeable turning direction is especially suitable for doing turning. This transferring-chain takes over the separate sheets as desired either directly or indirectly by running in the other direction adjacent a gripper-drum which can be put in action at will, and deposits the sheets on the conveyor belt of the feeding-table.

By being able to feed and turn the sheets according to these novel arrangements and the novel turning device of this invention, high speeds are obtained with recto and verso multi-colour printing without foregoing the demand that each printing unit of a multi-colour press must be able to run independently of all the others. This permits the lbuilding of standard machines consisting of as many standard units as desired with the smallest dimensions. However, this permits reaching high hourly output, such as up to 5,000 sheets per hour with normal run and at the same time turning the sheets. Whilst, for example, a machine for six colours and having a length of 55 (17 meters) has reasonable dimensions, an equivalent plant built in tandem fashion would have a length of almost (50meters) 165' and thus only have theoretical value.

A further improvement relates to feeding the sheet on the feeding-table. Hitherto, only separate sheets strayed from the turning-device, causing diiculties in conveying on the long tape-guiding, until reaching the front-lays. The slightest rhythm irregularities caused jiams. Practice has now secured the knowledge that it is quite possible to form a sheet stream in a reversed way contrary to the sheet-feeders known hitherto. Whilst. each succeeding sheet is put under the preceding one with these stream feede-rs so that the sheet that is being positioned at the front-lays is the rst loose one on top of the stream, the turning-chain according to the invention puts each succeeding sheet onto the proceeding one, so that the sheet in the foremost position at the front-lays lies beneath and is partly covered up by one or two of the succeeding sheets. Positioning of the respective `forcmost sheet by means of front and side lays is in no way aected by the reversed overlapped stream feeding and is done exactly.

The invention alfords a number of essential advantages. The small space required enables installing multicolour machines consisting of many printing units. In conjunction with the turning-device the invention enables any desired subsequent extension to a multi-colour machine. Short sheet travelling ways between turningdevice and sheet-feeding and guided sheet-conveying secure feeding in dead register at each following printing unit, even at high running speeds. A further increase in production is gained in that the sheets are led on the feeding-table in an overlapping stream from the turningdevice until reaching the printing unit. The printing units can be as easily switched over to different combinations as it is possible with web-fed rotogravure presses that are equipped with an auxiliary doctor to change the direction of one or more printing mechanism at will. The high hourly output that can be obtained whilst maintaining rst-class quality will of its own secure many orders for a sheet-fed printing machine according to the invention that were hitherto reserved for web-fed presses.

The drawings illustrate as a given example of the invention a sheet-fed yrotogravure printing press with ve printing units.

Fig. l is a side elevation of the press;

Fig. 2 is a diagrammatic side elevation of the press with the -sheet travel and the five colour printing on one side thereof;

Fig. 3 is a diagrammatic view similar to Fig. 2 but illustrating the path of travel and printing of one colour on one side and four colours on the other side of a sheet;

Fig. 4 is a further diagrammatic view similar to that of Fig. 2 but showing the path of travel and printing of two colours on one side `of a sheet and three colours on the other side; and

Fig. 5 is a side elevational view of a transferring and reversing chain for a sheet on an enlarged scale as used with the individual units of the press shown in Fig. l.

The sheet-fed printing machine illustrated consists of live printing units 16, 26, etc., in front of which is arranged feeder pile 1, Whilst at the other end of the machine are situated one or even two stacking boards. The printing units are connected closely one behind the other in the known manner according to the standard unit system and are separated from each other by a gangway. They are of uniform design and their cylinders 16, 26, etc. rotate in the same direction.

In practice two turning-devices are sucient for a machine consisting of five printing units. There is no turning taking place with a five-colour print 5 0 colour print) on one page and all transferring-chains run in the same direction. For a l/ 4 print turning is done after the rst print and after that the sheets are printed and nnished in four colours on the reverse. With a 2/ 3 colour print turning is only done after the second print. A turning-device after the`third and fourth printing unit would give 3/2 or 4/1 print, which is equivalent to 2/ 3 or l/ 4 print respectively, and thus a turning device is only required after the first and second machines.

-Sheets 2 are forwarded to the front and side lays from sheet-feeder 1 on feeding-table 13 in an overlapping way. A feeding-drum 14 takes over the resting sheets, draws them in an accelerated and known manner from the feeding-table and transfers them to the constantly rotating printing-cylinder y15. Picture-cylinder 16 effects one imprint per revolution. Following this, slower running conveyor-chains 17 lead the sheets through a long dryingchamber above the picture-cylinder, delivering them to the short delivery chains 18. Thev delivery chains 18 deposit the sheets, disposed in overlapping formation see Fig. 5 on the feeding-table 23 of the second printing unit, where the operations are repeated until the sheets,

printed with two colours ,and moving past the gripperdrum 4, reach the delivery-chains 28 of the second printing unit, which deposit them on the feeding-table 33 of the third printing unit. The belts and rollers normally used convey the sheets each time to the register means. After having passed through the fifth printing unit, the sheets are advantageously deposited on one or two stacking boards (Figure 2).

The mechanism for transferring the sheets from one printing stage to a subsequent stage is shown in greater detail in Figure 5. The sheets are passed by means of the conveyor-chain 17 to the delivery-chains 18, either directly, or indirectly over the gripper-drum 3', which is rotatable only in the direction of the arrow. The deliverychains 18 are adapted to be driven in each of two directions as shown by the two arrows, by either the sprocketwheel 6 or by the gripper-drum 3, and by changing the direction in which the chains are driven and by passing the sheets over the gripper-drum 3, it is possible to print the sheets in the subsequent printing stage on the opposite side from that already printed. Thus, when the sprocket-wheel 6 drives the delivery-chains 18 in the direction of the arrow pointing to the left in the drawing, the gripper-drum 3 is stationary. The sheets are passed by the conveyor-chain 17, past the gripper-drum, directly to the chains 18, and from the chains 18, through the conveyor-belt 10 to the next feeding-table 23. The sheets are thus not turned, but are printed on the same side in the next stage.

To elfect the drive of the delivery-chains 18 in the direction of the arrow pointing to the right in the drawing, the gripper-drum 3 is rotated. The sheets passed by the conveyor 17 are gripped by the drum 3 and pass over the drum before they are delivered to the chains 18, so that they are reversed before they are deposited on the next feeding-table, with the front edge of the sheets coming to bear against the stops 34, which are adjustable according to the length of the individual sheets. Thus the sheets are printed in the next printing stage on the side opposite to that already printed.

With this arrangement, the delivery-chains and turning- Ichains 18 are situated a little distance in front of the following printing units, i.e. at a distance of about a sheet length in front of the usual front-lays of the respective feeding-table. Thus, they lead the separate sheets directly to the feeding-table of the following printing unit. This shows that the way a sheet has to travel in between each turning-chain 18 and the front-lays of the following feeding-table is very short.

The delivery-chains 18k are provided with two sets of grippers 7 and 8, the grippers 7 being effective when the chains 18 are driven in one direction, and the grippers 8 being effective when the chains 18 are driven in the opposite direction. The chains 18 may also be provided with supporting wires, tapes, rods or the like which e11- close the chains and form a basket-like support for the sheets, and with spring-loaded resilient rollers 9, which are adjustable for height, and which are adapted to roll over and holld the sheets as soon as the grippers 7 or 8 are opened. The rollers 9 hold the sheets in position on the conveyor-belt 18 until the edges of the sheets reach a further set of guide-rollers 11. The plate 35 which cooperates with the rollers` 9 rotating with the chains 18, and which is provided below the conveyor-belt 10, is advantageously adjustable to the size of the paper being printed at the time.

A cam 12, which is provided to open the grippers 7 and 8, is adjustable for releasing the different sizes of sheets from the delivery chains 18 at the desired moment during the turning operation. The stops or abutments 34, being only used for the turning operation, limit the path of the sheets at their front edges, so that in spite of any inaccuracies in the turning operation, it is possible to observe the accurate rhythm required for the subsequent printing stage. The turning-chains 18 rotate vadvantageously at variable speed in such manner as to receive the sheets at the same speed as that of the chain conveying the sheets through the drying chamber, and deposit them ou the feeding-table at reduced speed. In order to gain time, they may rotate at an increased speed, if desired, before depositing the sheets. The reliable operation of the conveyor and turning means may also be assisted by an air blast or suction, i.e. by blast jets and suction jets.

Figures 1 and 3 show a machine according to the invention adapted for 1/ 4 printing, the sheets being passed over the gripper-drum 3 on to the delivery-chains 18 after having passed through the rst printing unit, so that one side of the sheet is printed with one colour as indicated by the little triangle labeled f and the other side with four colours as indicated by the little triangles labeled g, h, z' and j. Figure 2 shows the machine adapted for 0/ 5 printing as indicated by the little triangles labeled a, b, c, d and e, the sheets not being turned on their passage through the machine, and Figure 4 shows the machine adapted for 2/ 3 printing as indicated by the little triangles labeled k, l, m, n and o, the sheets being turned between the second and third printing unit.

After the turning operation, the rear edge of the sheets becomes the front of the sheet and should, therefore, also be cut. As hereinbefore described, any differences in size are taken into account either by the gripperopening cam 12 being shifted, or by the printing unit disposed in front of the turning device being put in corresponding mesh in regard to the main drive.

What I claim is:

l. In a multi-colour high-speed intaglio sheet-fed rotogravure printing machine having a plurality of printing units arranged in a horizontal line one behind the other in close spaced relation and each having a feeding table means positioned adjacent its printing unit for feeding sheets thereto, a selective sheet turning and delivery means for each successive unit comprising a turning drum and an endless conveyor chain, said turning drum being positioned adjacent the endless conveyor chain for feeding sheets thereto and said endless conveyor chain beingV positioned over a portion of said feeding tab-le means and intermediate the turning drum and the feeding table means, said endless conveyor chain being supported for turning in either direction, said chain in `one direction of turning receiving sheets from said turning drum and in the opposite direction of turning receiving sheets directly, said chain having grippers for gripping a sheet in either direction of turning, an adjustable positionable actuator in the path of movement of said grippers for releasing a sheet, an adjustable positionable stop member positioned adjacent said feeding table in the path of movement of a sheet for limiting the travel of the sheets in one direction of turning of the endless chain.

2. In a printing machine of the` character described in claim 1 wherein said feeding table means includes an endless conveyor having an upper run and a lower run, said upper run having a portion thereof positioned below a run of said endless conveyor chain, said feeding table means also including a feed plate positioned under said upper run portion of said endless conveyor of the feeding table means and a guide roll on said conveyor chain adapted to pass over said feed plate and press a sheet against the run of the endless conveyor of the feeding table passing over the feed plate.

3. A multi-colour high-speed intaglio sheet-fed rotogravure printing machine comprising in combination a plurality of `separate rotary printing units arranged in horizontal line one behind the other in close-spaced relation, all turning in the same directionjand having a front lay and feeding table at the receiving end thereof, an endless delivery conveyor means having grippers `for sheets delivered from each unit after printing, selective sheet turning and idelivery mechanism for each successive printing unit, positionable adjacent said delivery conveyor of the preceding unit and above and overlapping a feeding table of a next successive unit for feeding sheets thereto, said selective sheet turning and delivery mechanism being adapted to be selectively setto deliver a sheet direct to the feeding table or to turn the sheet over and deliver it to the feeding table with which it is associated, said feeding table having means moving sheets therealong at a linear speed less than the speed that the sheets are fed thereto by said selective sheet turning and delivery mechanism whereby the sheets are received on and moved by said feeding table with each successive sheet lying on and overlapping the preceding sheet.

4. A multi-colour high speed intaglio sheet-fed rotogravure printing machine comprising in combination a plurality of separate rotary printing units arranged in horizontal line one behind the other in close-spaced relation, all turning in the same direction and having a front lay and feeding table at the receiving end thereof, an endless delivery conveyor means having grippers for sheets delivered from each unit after printing, selective sheet turning and delivery mechanism for each successive printing unit, positionable adjacent said delivery conveyor of the preceding unit and above and overlapping a feeding table of a next successive unit for feeding sheets thereto, said selective sheet turning and delivery mechanism being adapted to be selectively set to deliver a sheet direct to the feeding table or to turn the sheet over and deliver it to the feeding table with which it is associated, said sheet selective turning and delivery mechanism comprising a gripperl drum and an endless conveyor chain, the latter of which being adapted to turn in either direction, said gripper [drum being located adjacent said endless conveyor chain and selectively positionable adjacent the delivery conveyor o'f the next preceding unit to` receive a sheet and deliver it to the endless conveyor chain set to run in a direction to turn over the sheet it receives from said gripper drum and deliver it to said feeding table positioned directly therebelow.

5. A multi-colour high-speed intaglio sheet-fed rotogravure printing machine according to claim 4 wherein said sheet selective turning and delivery mechanism comprises a gripper drum turning in idling position and an endless conveyor chain having an end adjacent said gripper drum and positioned adjacent said delivery conveyor of a preceding unit to receive a sheet therefrom and deposit it onto the feeding table therebelow of the next printing unit in the same attitude as received from the delivery conveyor, means for driving said endless conveyor chain and feed means on said feed table at relative speeds to each other whereby said sheets being deposited onto the delivery table are deposited in overlapping position,` one upon the next preceding sheet.

6. A multi-colour high-speed intaglio sheet-fed rotogravure printing machine according to claim 4 wherein said delivery conveyor means for sheets delivered from each unit includes an endless gripper chain means extending upwardly from a discharge point `on the unit with which it is associated, then rearwardly over the machine, thence forwardly and then downwardly into delivery position adjacent said sheet selective turning and delivery mechanism for the next succeeding `printing unit.

References Cited in the file of this patent UNITED STATES PATENTS 1,637,713 Schuneman Aug. 2, 1927 1,949,001 Albrecht Feb. 27, 1934 1,966,287 Fischer July 10, 1934 2,245,343 Hunting June 10, 1941 2,723,119 Engebretson et al. Nov. 8, 1955 FOREIGN PATENTS 393,992 Great Britain f June 19, 1933 496,753 Great Britain Dec. 5, 1938 876,105 France Oct. 28, 1942

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