US3921519A

US3921519A - Rotary printing machine

Info

Publication number: US3921519A
Application number: US478388A
Authority: US
Inventors: Peter Zimmer
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-11-15
Filing date: 1974-06-11
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25

Abstract

A rotary printing machine for printing designs the pattern of which is repeated and which is printed by at least two rotating printing cylinders. Each cylinder is adapted to be brought temporarily out of contact with the material to be printed. Means are provided for moving each of the cylinders and the material relative to each other, and each such means is activated by a digital counting device having memory capabilities after a preset number of impulses, such number depending on the angle of rotation of the respective cylinder.

Description

United States Patent Zimmer ]*Nov. 25, 1975 [5 1 ROTARY PRINTING MACHINE 3,139,025 6/1964 Chambon 101/182X ,19 ,4 1. 101 184 1 1 Inventor: Peter 11mm", were Sparchen 54, 3223 03-? 11322 5232123213.? 1011172 Kufstem Ausma 3,291,044 12/1966 Van Der Winden 101/118 1 Notice: The portion of the term of this big giis ig 18 fg z gi to ,SePL 3,359,893 12/1967 Zahn et a1 101/218 x een lsclalmed- 3,467,007 9/1969 Stotzeret 31.... 101/184 x 22 Filed; June 11 1974 3,503,232 3/1970 Farrer et a1 101/172 3,527,164 9/1970 Buck 101/184 X [21] Appl. No.: 478,388 3,587,458 6/1971 Feier, 101/120 3,774,533 11/1973 lchinose. 101/119 Related Applcamn D 3,834,309 9 1974 Zimmer lOl/ll6 [63] Continuation-in-part of Ser. No. 304,935, Nov. 9,

1972 abandoned Primary Examiner.1. Reed Fisher Attorney, Agent, or FirmWenderoth, Lind & Ponack [30] Foreign Application Priority Data Nov. 15,1971 Austria 9818/71 [57] ABSTRACT 52 us. c1. 101/116; 101/181; 101/182 A rotary i machine for Prim/31188191151116 [51] Int Cl 2 H 5/06 tern of wh1ch 1s repeated and whlch 1s printed by at [58] Field of Search 101/11s-120, least two mtatmg Prmmg f Each l01/178 181 182 185 248 adapted to be brought temporarily out of contact with the material to be printed. Means are provided for [561 83:21 2112321: 211113 21 2121: 1128;121:315

, u UNITED STATES PATENTS digital counting device having memory capabilities JBOUIB after a preset number of impulses such number deattey... 3 13 2,573,097 longs] Epstein 01/172 UX i iletecimg on the angle of rotat1on of the respectwe cyl 2,663,256 12/1953 Chamb0n.. 101/228 I 2,893,310 7/1959 Johnson 101/182 8 Claims, 8 Drawing Figures OUTPUT LOAD COUNTER US. Patent Nov. 25, 1975 Sheet10f4 3,921,519

F/a. 3b

US. Patent Nov. 25, 1975 Shset 2 of4 3,921,519

IIUI

L'Hl

I OUTPUT CLEAR LOAD PRESET A I 3 COUNTER Z CLEAR YOUTPUT LOAD PRESET US. Patent Nov. 25, 1975 Sheet3of4 3,921,519

. ,1 I LU c LEAR COUNTER A OUTPUT is? is? W80 HAM l-MI i PRESET( LOAD BI 84 T T r f CLEAR Y COUNTER k B .r\.

OUTPUT 9O 93 7 9O 85 PRESET LOAD 9| I (Bf FLIP-FLOP 86 U.S. Patent Nov. 25, 1975 Sheet4of4 3,921,519

ROTARY PRINTING MACHINE This is a continuation-in-part of application Ser. No. 304,935, filed Nov. 9, 1972, now abandoned.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION It is an object of the invention to provide a printing machine which renders it possible to print long repeated designs by using relatively small printing cylinders, these printing cylinders being adapted to sequentially be brought temporarily out of contact with the material to be printed. Thus, each cylinder prints only part of the total repeated pattern, and the various cylinders cooperate to print the whole repeated pattern or design.

In order to ensure correct timing of the lifting and lowering of the cylinders away from and toward the material, as well as the precise combining of the various parts of the pattern printed by each cylinder, the invention further proposes to provide a digital counter de vice having memory capabilities for each cylinder which activates the means for lifting and lowering each cylinder after a preset number of impulses, such number depending on the angle of rotation of each of the respective cylinders. Thus the speed ratio of the different gears of the machine is of high importance in order to obtain the correct movement of the cylinders or the material in accordance with the desired pattern.

Theimpulses conveniently are taken by tooth detecting means, such as optical or inductive devices, from a toothed disc fixed, e.g., on the drive shaft for the cylinders.

The present invention is hereinafter described with reference to a rotary screen printing machine to which it is particularly suitable. The invention, however, is not limited to this specific type of machine but may be applied to all machines having rotary printing cylinders, e.g., to machines using roller printing, photogravure printing, etc.

In accordance with a preferred embodiment of the invention involving a rotary screen printing machine, the printing machine includes a printers blanket tensioned between two guide rollers, one of which is driven and moves the printers blanket, which in turn drives the other guide roller, the rotation of which is' transmitted to a main device shaft by means such as bevel gears and a universal-joint shaft. The main drive shaft extends through transmission devices for each A toothed disc is fastened to the end of the main drive shaft, and has a number of teeth equal to or a whole multiple of the number of teeth of each drive gear. A tooth detecting means such as a photocell arrangement or an inductive transmitter device registers the presence or passage thereby of each tooth of the toothed disc and emits one impulse or a whole number printing station including screens with Squeegees.

of impulses for each tooth of the toothed disc.

These impulses are transmitted to a digital counting.

device for each screen. Each :such device is set to emit an impulse after receipt of a predetermined number of impulses from the tooth detecting means, indicative of the exact angular rotation of the respective printing screen or cylinder. Thus, the impulse from each device occurs at a well determined angular position of the corresponding printing screen, and therefore also at a predetermined point in the overall repeated pattern. Variation of this predetermined point is easily achieved by manual addition or adjustment of a desired number of impulses.

The printing cylinders are journalled in bearings which are mounted on frames in a known manner and which are lifted by hydraulic piston-cylinders assemblies, the operation of which. are controlled by magneto-hydraulic valves in response to the impulses generated by the respective digital counting devices. Thus, on one such impulse the respective printing cylinder is lifted from a position in contact with the material to be printed, and on receipt of a second such impulse islowered from such lifted position. Therefore, each cylinder rests on the material for an exactly defined period.

The invention may be used in a machine wherein the length of the overall repeated pattern is a whole multiple of the circumference of one of the screens. However, the invention is also applicable to a machine wherein such is not the case, that is wherein the length of the overall repeated pattern is not a whole multiple of the circumference of one of the screens.

However, in such a case the machine must include means to impart an additional rotation to the cylinders when they are lifted off the material. For this purpose, a supplementary drive shaft may be provided parallel to the main drive shaft, the two shafts being connected by suitably chosen reduction gears. Both shafts act on sets of screen transmission gears. Each such set may include any suitable means to impart an additional forward or backward rotation to the respective cylinder when it is in the lifted position. For instance each set of gears may'consist of a part: which adds or subtracts rotation to the respective screens and a Maltese-cross drive, or of a differential drive and a storing device for providing a predetermined additional angular movement.

If such a supplemental drive is provided, it is possible to print a relatively long pattern the total repeated length of which is not a whole multiple of the circumference of the cylinders. This additional movement can be freely chosen but is equal for all cylinders. In such an arrangement preferably the impulses which characterize the angular position of each cylinder are taken individually from each cylinder.

Instead of lifting or lowering the printing cylinders, the contact between the latter and the material may also be effected or interrupted by lifting and lowering the transport blanket supporting the material.

BRIEF DESCRIPTION OF THE DRAWINGS The above inventive features will be described in more detail below with reference to the accompanying drawings wherein:

FIGS. 1a and lb are respectively a schematic illustration of one embodiment of a screen arrangement suitable for use of the present invention, and a pattern printed by such arrangement; M

FIG. 2 is a detailed illustration of the present invention used with the screen arrangement of FIG. 1a;

FIGS. 3a and 3b are respectively a schematic illustration of a further embodiment of a screen arrangement suitable for use of the present invention, and a pattern printed by such arrangement;

FIG. 4 is a detailed illustration of the present invention used with the screen arrangement of FIG. 3a;

FIG. 5 is a schematic view, partially in section, through one of the screens of FIG. 4 and the means for imparting rotation thereto; and

FIG. 6 is a partial view of a printing screen station illustrating an arrangement for lowering the transport blanket rather than raising the screen.

DETAILED DESCRIPTION OF THE INVENTION In the following detailed description, reference will be made to perforated cylinder screens having therein squeegee devices mounted in a known manner. However, the invention is not limited to this specific arrangement, but may be used in other rotary cylindrical printing machines.

FIG. la shows the printing cylinders, such as screen stencils l, 2, 3 and 4 which together print an overall repeated pattern on the web of material 9, whereby the pattern is longer than the circumference of any one of the screens. The web of material 9 is supported by the printers blanket l0, and the blanket 10 is moved and guided over two guide rollers, one 11 only of which is shown in FIG. la. The printed pattern shown in FIG. lb is divided into several

partial patterns

5, 6, 7, 8. The partial pattern 5 extends from the dotted line 12 to line 13, the partial pattern 6 extends from line 13 to line 14, the partial pattern 7 extends from line 14 to line 15, and the partial pattern 8 extends from line 15 to line 16.

Only three quarters of the circumference of each screen 1 to 4 are provided with a pattern printing portion 17, the remaining 90 portion 18 of the circumference being a non-printing portion, i.e., having a wall without any perforations. The screen 1 is provided with a printing portion for the part 5 of the pattern, the screen 2 a printing portion for part 6, the screen 3 a printing portion for part 7, and the screen 4 a printing portion for part 8.

In the position of the web shown in FIG. lb, part 5 has already been printed by the screen 1, the screen 1 being precisely in the position for the beginning of the printing of another part 19 which is identical with part 5. Also, screen 2 has already printed part 6 of the pattern on the material web, the screen 2 being in a lifted position and awaiting a command for printing another part identical with part 6 which, however, has yet to be conveyed to screen 2. On the contrary, screen 3 is in the printing position and has printed a portion of part 7. That is, part 7 has been printed from line 14 up to the dotted line 20, whereas the section between lines 20 and 15 has yet to be printed by screen 3. Screen 4 has not yet printed part 8 of the pattern on the material web and is in the lifted position. Screen 4 will be lowered at the moment when the trailing end of the nonprinting circumferential portion 18 of screen 4 is at the lowermost position of the circumference of the screen.

To carry out the printing process shown in FIG. 1, the machine is provided with a control mechanism as shown in FIG. 2. The printing machine 21 contains the four screens 1 to 4 which are positioned in supports 22 which may be lowered or lifted toward or away from the printers blanket 10 of the printing machine 21, i.e., into and out of contact with material 9. It is of course to be understood that the scope of the present invention includes machines having a plural number of screens less than or greater than four. The lifting and lowering movement is effected by hydraulic pistoncylinder mechanisms 23, such lifting movement being limited so as to insure that screen gears 38 connected to each screen remain engaged with driving gears 24. These driving gears 24 are driven from a guiding roller 25 of the machine, whereby a main drive shaft 28 is kept synchronized with the movement of the printers blanket by means of bevel gears 26 and a universaljoint-shaft 27. The main drive shaft 28 carries worm or spiral gears 29 which transmit the movement of the main drive shaft 28 to the driving gears 24. The ratio of the spiral gears 29 are 1:1, and therefore the rotational speeds of gears 24 and main drive shaft 28 are the same. In the specific example described the gears 24 have 32 teeth. At the end of shaft 28 is fixed a toothed disc 30 which also has 32 teeth. A tooth detecting means 31 such as a light beam-photocell device or a proximity detector of the inductive type detects the passage thereby of each tooth of toothed disc 30 and emits an impulse representative thereof. Means 31 emits 32 impulses for each revolution of shaft 28, such impulses being sent to digital counter devices, which in the illustrated embodiment are counter-relay mecha nisms 33, to be described in more detail below. Since the impulses from means 31 are rather faint, they are amplified by an amplifier 32. Due to the identical number of teeth on each gear 24 and on disc 30, each impulse of tooth detecting means 31 corresponds to one tooth of gear 24 and also of screen gear 38. In the specific embodiment described each of gears 38 has 108 teeth.

As stated in connection with FIG. 1, one quarter of the circumference of each screen comprises a nonprinting portion, and three quarters of the circumference of each screen comprises a printing portion. Thus, the printing portion of the circumference corresponds to 81 teeth of screen gear 38, and since each tooth corresponds to one impulse from tooth detecting (and impulse generating) means 31, the printing period (from the beginning to the end of the printing portion) for each screen is exactly 81 impulses. On the other hand, the period for the passage of the non-printing portion of the circumference of each screen is 27 impulses. Thus, each of the

partial patterns

5, 6 7 and 8 shown in FIG. 1b is equivalent to 81 impulses. The total length of the overall repeated pattern, i.e., the length of the material web from line 12 to line 16 therefore corresponds exactly to 4 X 81 impulses, i.e., 324 impulses. Further, since the total circumference of each screen corresponds to I08 impulses, the total length of the overall repeated pattern corresponds exactly to three times the circumference of each of the screens. It of course is to be understood that these specific examples of gear teeth and impulses are intended to be exemplary only, and not limiting to the scope of the invention.

The impulses from tooth detecting means 31 are fed to the counter-relay mechanisms 33 via amplifier 32, one assembly 33 being provided for each screen. The following description will be with regard to the mechanism 33 for the screen 4, the mechanisms 33 for screens 1, 2 and 3 being shown schematically for the purpose of clarity. To initially set screen 4, the web is moved such that line of the pattern thereon lies slightly (e.g., a few cms) before the position whereat printing thereon of partial pattern 8 by screen 4 would begin. Then the screen 4 is manually adjusted, either by disengaging the gear 38 and turning the screen by hand, or by means of a known type of screen adjusting device which may be provided at each printing station, such that the beginning of the printing portion of screen 4 will coincide with line 15 of the material web on further movement of the screen and the material web. If exact alignment is not obtained in a first printing pass, exact alignment of screen 4 (as well as the other screens) may be achieved by the mentioned known type adjusting device during subsequent printing passes. However, before continuing to print, A-counter unit 34 of mechanism 33 for screen 4 is cleared by a manually instituted clearing impulse in a known manner. A preset unit 36 is set to store a predetermined number, in this case the number 324. If an impulse is manually applied to the load terminal 43, the number stored in A preset unit 36 is transmitted to the A counter unit 34.

On further driving of the machine (moving the web) each tooth of disc 30 induces an impulse in means 31, and these impulses are fed via amplifier 32 to the input terminal 40 of A-counter unit 34. Each of these impulses decreases the number contained in A-counter unit 34 by one. After 81 impulses partial pattern 8 of the web has been printed and the content of A-counter unit 34 is 243. A similar setting process is then carried out for B counter unit 35. B preset unit 37 is also set at the number 324. Screen 4 is rotated until the end of the printing portion of screen 4 is reached (which may be carried out at a very slow screen rotation speed), and the machine is stopped. A clearing impulse is manually induced in a known manner into B-counter unit 35 to clear counter 35 to zero. The same impulse goes over line 39 to the load terminal 44 of B preset unit 37, and counter 35 is set to the number contained in B preset unit 37, i.e., 324. When the clearing impulse mentioned above is fed to the terminal 43 the impulse in line 39 acts on terminal 44 of preset unit 37. Thus, counter 35 is loaded with number 324 while counter 34 is loaded with number 243.

The assemblies 33 for screens 1, 2 and 3 are similarly initially set, of course however in their respective phase relationship for respectively printing

partial patterns

5, 6 and 7.

The machine is then started, and the following takes place (with regard to screen 4).

Each impulse coming from tooth detecting means 31 and fed via amplifier 32 to the counters 34 and 35 diminishes each of the numbers contained therein by one. Counter 34 is the first one which is decreased to zero, and this occurs exactly 324 impulses after counter 34 was set, i.e., after partial pattern 8 of the material web was starting to be printed. Exactly when counter 34 reaches Zero, the next section of the material web which corresponds to partial pattern 8 has arrived at exactly that point where the same is to be printed by screen 4. Now, when counter 34 reaches zero it emits at its output terminal 42 an impulse which, on the one hand, is applied to the clearing terminal 45, and, on the other hand, causes the repetition of the loading process since it is applied to the terminal 43 of the preset unit 36.

Furthermore, this impulse is fed to the terminal 46 of flip-flop 47 which is switched over and emits an impulse from output terminal 48 This impulse is fed via amplifier 49 to a magnetic valve 50 (to be described in more detail below) which is shifted to cause screen 4 to be lowered, i.e., to move into its printing position.

After a further 81 impulses, counter 35 reaches zero and emits an impulse at its output terminal 51. This impulse is applied to clearing terminal 43 and to load terminal 44 to initiate a new loading process of counter 35 via preset 37. Again counter 35 is loaded by the preset unit 37 with the number 324, the starting number for a new countdown. The impulse leaving terminal 51 is furthermore fed to the input terminal 46 of flip-flop 47 which again is switched over, and through output terminal 48 emits a signal which is transmitted via amplifier 49 to magnetic valve 50 which is shifted back to the position shown in FIG. 2 to cause screen 4 to be lifted. Thus, these alternating commands to valve 50 are sent based on the numbers of impulses fed into counter-relay mechanism 33. Emission of these signals takes place after a predetermined number of impulses, which corresponds to a predetermined length of the material web having passed through the machine.

Magnetic valve 50 is connected at its entry 50' to a pump 52 via a conduit 53. In the position shown in FIG. 2 entry 50' is connected to exit 54 of the valve in communication with lower chamber 55 of pistomcylinder assembly 23. Therefore, the piston together with support 22 and screen 4 will be lifted. The upper chamber 56 is connected via conduit 57 to exit 58 of magnetic valve 50. In the position shown, liquid will flow from exit 58 to entry 59 connected to the collecting pipe 60. Oil contained in chamber 56 will thus be reconveyed into reservoir 62 via return line 61.

It will be apparentthat the operations of mechanisms 33, valves 50 and assemblies 23 for screens 1, 2 and 3 will operate in exactly the manner described above, with the obvious exception that each unit will operate at a distinct and predetermined time. That is, each unit will be out of phasewith the other units. In the specific examples described, the screens operate sequentially out of phase by 81 impulses in the order of 1, 2, 3 and 4.

FIGS. 3a and 3b show an embodiment of the present invention employing two printing screens to print an overall repeated pattern, wherein however the length 63 of the overall repeated pattern is not equal to a multiple of the circumference of one screen. In the specific example of FIG. 3, the overall pattern length 63 is not equal to twice the circumference of screens 64 or 65, which respectively have non-printing portions 66 and 67. Lifting and lowering of the screens of course must be effected only when the non-printed portions are in the area of contact with material web 68. The latter moves in direction 69 and the screens rotate in direction 70. Screen 64 is provided with a printing portion for printing partial pattern 71, and screen 64 with a printing portion for printing partial pattern 72. In the position shown in FIG. 3 screen 64 has just finished its printing operation and has printed partial pattern 71 on the material web 68. When the material web has moved by the distance 73, the end 74 of partial pattern 71 will arrive under screen 65 which will be lowered into its printing position with the trailing edge 75 of the nonprinting portion 67 coinciding with end 74. Subsequently partial pattern 72 is printed by screen 65. The pattern in this part is shown in dotted lines in FIG. 3b in order to indicate that, in the position illustrated, it has not yet been printed.

If the material web is provided with a pattern in the manner shown in FIG. 3b, it is possible to print a pattern of a length greater than the circumference of one screen. However, it must be noted that the overall pattern length 63 is not a multiple of the circumference of the two screens but is somewhat shorter than the sum of the circumferences of the two screens. This means that the end of one overall pattern, or the beginning of a new partial pattern to be printed by screen 64, will not align with the leading end 76 of the printing portion of screen 64 if screen 64 is always rotated in synchronization with the material web. Therefore, it is necessary to take steps to insure such proper alignment.

According to the invention, an adjusting movement is imparted to the screen 64 during the period in which it is in the lifted position. In other words, after the screen 64 has printed partial pattern 71 and subsequently has been lifted, an additional rotational movement is imparted to screen 64. On the other hand, screen 65 at the moment shown in FIG. 3a is in the lifted position and receives such an additional rotational movement.

To carry out the printing process shown in FIGS. 3a and 3b a device according to FIG. 4 is provided. In FIGS. 4 and 5 the two screens are designated by reference numerals 64 and 65, these screens print alternately according to the process described with reference to FIGS. 3a and 3b. The lifting and lowering movements necessary for this process are obtained in the following manner.

Each screen assembly has a tooth detecting means 31 to detect the passage thereby of each tooth of respective driving gear 24 and to emit impulses representative thereof. In the specifically described embodiment, the printing portion of screens 64 and 65 extend substantially over 80% of the screen circumferences, the remaining of the screen circumferences having the non-printing portions 66 and 67, respectively. The screen gears 77 fixed to the ends of the screens have 108 teeth, and thus the length of the printing portion of each screen corresponds to approximately 86 teeth, and the length of the nonprinting portion of each screen corresponds to approximately 22 teeth. The screens will be adjusted as follows.

Screen 64 is turned to a position in which it is just about to contact the material web 68 with the leading end 76 of the printing portion. At the same time counter-relay mechanism 82 for screen 64, similar to mechanism 33 described above, is set in a manner as will be described below. with reference to the adjustment of screen 65. After the partial pattern 71 of screen 64 has been printed, the material web will be brought under screen 65, and screen 65 will be turned by hand into a position such that the leading end 75 of the printing portion of screen 65 will coincide with the end 74 of partial pattern 71. Now, counter-relay mechanism 82 associated with screen 65 will be adjusted as follows. A counter unit 78 is set to zero by a manual impulse applied to terminal 79 in a known manner. The A preset unit 80 is set to the desired predetermined number, i.e., in the example, 216 2 X 108. Another manual impulse applied to load terminal 81 transfers the number 216 into the counter 78. In subsequent printing, each tooth passing by tooth detecting means 31 of screen 65 creates an impulse which is conveyed via amplifier 83 to the counter 78 to decrease the number contained therein by one. The partial pattern 72 printed by screen 65 is simultaneously printed onto the material web. When the end of the pattern 72 is reached, counter unit 84 and preset unit 85 are set in the same manner as described above in connection with counter unit 78 and preset unit 80. Thus, counter 84 also initially contains the number 216. Each further impulse fed by means 31 to

counters

78 and 84 diminishes the numberes contained therein by one. The flip-flop 86 is illustrated in a position in which magnetic valve 87 effects a lifting of screen 65 by means of piston-cylinder assembly 88. The next impulse given to the flip-flop 86 switches the flip-flop such that, the next impulse therefrom will shift magnetic valve 87 to cause lowering of screen 65. This next impulse arrives exactly after the counter 78 has registered 216 impulses of the device 31. This, in turn, corresponds to exactly two revolutions of screen 65. Therefore, after this number of impulses screen 65 is just about to again start printing, i.e., in a position in which it must be lowered. Now, when counter 78 reaches zero, an impulse is emitted at its output terminal 89, such impulse being sent, on the one hand, to the clear terminal 79, and on the other hand, to the input or load terminal 81 of the preset unit 80. The clearimpulse sets counter 78 to precisely zero, and the load impulse at the terminal 81 of preset unit 80 causes the same to again transmit the number 216 to counter 78. At the same time, the output impulse from terminal 89 of counter 78 is transmitted to flip-flop 86, causing the same to switch-over. Consequently, it gives via amplifier 90 and magnetic valve 87 a command to pistoncylinder assembly 88 for lowering screen 65.

When screen 65 has finished its printing process, B- counter unit 84 will reach Zero, and will emit an output impulse, whereby the counter 84 will again be loaded with number 216. At the same time impulse is conveyed to flip-flop 86 which again will switch-over and in turn emit an impulse via amplifier 90 to the magnetic valve 87 to shift the position thereof to cause pistoncylinder assembly 88 to lift screen 65.

The same cycle is effected in all elements associated with screen 64. However, there is of course a phase difference with respect to screen 65.

Piston-cylinder assemblies 88 are fed with fluid such as oil by pump 91 from reservoir 92. The fluid is pumped into either the upper or lower chambers of the respective assemblies, as required at a given time, and out from the opposite chambers through magnetic valves 87 into the collecting pipe 93 and therefrom into reservoir 92.

When each of the screens 64 and 65 are in their lifted position. an additional rotary movement is imparted thereto by gear means 94. For this purpose, a secondary drive shaft 97 is driven by main drive shaft 95 via gearing 96 including gears 103 and 104. Main drive shaft 95 and drive gears 24 have a gear ratio of 1:1, i.e..

the rotational speed of drive shaft 95 is equal to that of drive gear 24. However, this is only true for the periods during which no additional rotary movement is imparted to the drive gears 24 by the Maltese-cross mechanism 98.

Drive shaft 95 carries worm or spiral gears 99 which each engage with worm or spiral gear 100, as shown in FIG. 5. Spiral gear 99 has twice as many teeth as spiral gear 100, i.e., the rotational speed of spiral gear 100 is the double of that of gear 99. Rotational speed of drive shaft 95 is transmitted to planetary shaft 102 by a differential gear arrangement 101. Spiral gear 100 is not keyed to shaft 102 but turns loosely thereon. Shaft 102 extends from the left in FIG. and has fixed on the opposite end thereof drive gear 24, and carries transversal stub shafts for the two bevel gears 109 of differential gear arrangement 101. Also, gear 108 is not keyed or otherwise fixed to shaft 102. During the periods in which no additional rotary movement is to be imparted to drive gear 24 which is fixed to shaft 102, element 108 remains stationary, gear 100 rotates at the twice the normal speed, i.e., the speed of drive shaft 95, and beveled gears 109 are rotated from the left by spiral gear 100 at the double speed. Bevel gears 109 roll at their right side on stationary gear 108. Thus, the centerlines, i.e., the stub shafts mentioned above, rotate at the normal speed. As the stub shafts are fixed to shaft 102 the latter also rotates at the normal speed.

As mentioned above, each screen 64 and 65 must receive an additional rotary movement once for each two revolutions thereof. This is achieved by Maltese-cross mechanism 98. One has to realize, however, that these two revolutions must be brought about during a period of movement of material web 68 equal to the distance 63. This equals a rotation of drive shaft 95 corresponding to twice the number of teeth corresponding to the engraved circumference, i.e., 2 X 86 172 teeth. As the number of teeth of drive gear 24 is 32, gear 103 must also have 32 teeth. However, gear 104 must have 172 teeth. Thereby it is achieved that the secondary drive shaft 97 performs exactly one revolution for each two revolutions of the screen, keeping in mind that an additional rotation is imparted to the screens, but not to shaft 97. By each revolution of secondary drive shaft 97 the Maltese-cross 105 is turned through 90. This quarter of a revolution of Maltese-cross 105 must be sufficient to turn gear 24 by twice the number of teeth (i.e., 22 teeth) corresponding to the non-printing portion 66 or 67 of the circumferences of screens 64 or 65. For this purpose intermediate gearing 106 is provided which may be of the interchangeable type. The output of this gear is transmitted via spiral gear 107 to gear 108 of the differential gear 101. In the embodiment described the total gear ratio between Maltese-cross 105 and bevel gear 108 of the differential gear 101 must be exactly 11. If so. gear 108 will perform exactly 2.75 revolutions on each quarter revolution of the Maltesecross 105. Such 2.75 revolutions are halved by the operation of differential gear 101, i.e., shaft 102 receives an additional rotational speed which is half the speed of gear 108. Thus, shaft 102 performs 1.375 revolutions for each quarter revolution of Maltese-cross 105.

As gear 24 has 32 teeth, 1.375 revolutions of thereof teeth (2 X 108) during a period of time corresponding to the movement of material web 68 over a distance 63, corresponding to a rotation of drive shaft of 172 teeth (2 X 86) or to the sum of the printing portions of the circumferences of screens 64 and 65. It of course is to be understood that the precise gear ratios and number of screens employed in the specific example of FIGS. 3-5 is intended to be exemplary only, and not limiting to the scope of the invention.

Instead of lifting or lowering the printing cylinders, the contact between the latter and the material may also be effected or interrupted by lifting and lowering the transport or printers blanket supporting the mate rial. Such arrangement is shown in FIG. 6. The printers table 133, e.g., including a magnet bar, is moved vertically by the hydraulic cylinder 123. The table slides in lateral guides 134, and a parallel construction (not shown) prevents tilting of the table. The toothed gear or disc is fixed to the same shaft as the drive gear, and initiates a control mechanism, in the same manner as described above with regard to FIGS. 2 and 4, for the control of cylinder 123.

In order to ensure proper lowering of the transport blanket together with the printers table, the latter may be provided with vacuum chambers which suck the blanket down tightly to the surface of the table. It is further possible to arrange the printers tables such that the transport blanket has a polygonal shaft when pressed onto the tables. When single tables are lowered the blanket will rest on the upper surface of such corresponding table.

As already mentioned the invention is not limited to the examples described above. For instance, the additional rotation might be imparted to the individual repeat gears by a combination of a differential drive and a stepping motor which is switched on at the moment of maximum lift of the printing cylinder.

Further, it is to be understood that the various gear ratios discussed above are intended to be exemplary only, and not limiting.

Still further, it is to be understood that the digital counter devices need not be the

specific mechanisms

33 and 82 described above. Rather, such eevices may be any known type of electrical, mechanical or electromechanical device which has memory capabilities and which is able to receive impulses or signals in a digital manner and to emit a command after the receipt of a predetermined number of impulses.

In the above discussed specific embodiments, counters 34, 35, 78 and 84 are integrated counter circuits, of which there are numerous on the market. One such counter circuit is the Decade Counter SN. 7490 manufactured by Texas Instruments. Also, presets 36, 37, 80 and 86 may be of the known type of diode or transistor memory switch designated to maintain or terminate current or voltage to a counter at predetermined intervals. Further, flip-flops 47 and 86 may be any of the many known types on the market. One such flip-flop is the Dual JK 7473 manufactured by Texas Instruments.

It is to be understood that the above specific examples are not to be considered limiting to the scope of the invention. Many other types of components are equally employable, as will be understood by those skilled in the art. Many marketers of such components publish expansive brochures and catalogs for the assembly of counter and memory control circuits.

Still further, those skilled in the art will understand that the above discussed counter and memory functions can equally be accomplished by mechanical devices, such ratchet arrangements.

I claim:

1. A rotary cylinder printing machine comprising:

a frame means providing a flat surface for supporting material to be printed;

at least two printing devices supported on said frame means for printing said material, each of said printing devices including a rotary printing cylinder, each of said rotary printing cylinders having a first circumferentially extending printing portion and a second circumferentially extending nonprinting portion;

means for moving said material over said flat surface for sequential contact and printing by the first printing portions of the rotary printing cylinders of each of said printing devices;

driving means, operable by said means for moving, for continuously imparting a constant first rotary movement to the rotary printing cylinders of each of said printing devices and for thus rotating said rotary printing cylinders at a first constant rotary speed equal to the speed of said first rotary movement;

lifting device means connected to each of said printing devices and to the respective adjacent portion of said flat surface for sequentially moving each of said rotary printing cylinders and the respective adjacent portion of said flat surface relative to each other, and for thus sequentially moving each of said rotary printing cylinders out of contact with said material;

means operatively connected to said driving means for indicating the angular positions of rotation of said rotary printing cylinders, with respect to the respective positions of said first printing portions and second non-printing portions thereof;

means positioned to detect the indication of said angular positions and to transmit impulses representative thereof;

a separate digital counting means connected to said means to transmit and to each of said lifting device means for counting the number of said impulses from said means to transmit and for activating said lifting device means upon the counting of a predetermined number of said impulses, thereby moving each of said rotary printing cylinders and said material into and out of contact in a predetermined sequence dependent upon said angular position of respective of said rotary printing cylinders; and

additional rotation means, connected to said driving means, for imparting an additional second constant rotary movement to each of said rotary printing cylinders only when out of contact with said material, and for thus changing the speed of rotation of each of said rotary printing cylinders to a second constant rotary speed. equal to the sum of the speeds of said first and second rotary movements, only when out of contact with said material.

2. A machine as claimed in claim 1, wherein each of said rotary printing cylinders comprises a rotary screen; each of said first printing portions comprises a circumferential length of said respective screen having perforations therein; and each of said second non-printing portions comprises a circumferential length of said respective screen having no perforations therein.

3. A machine as claimed in claim 1, wherein said driving means comprises a cylinder gear fixed to each of said rotary printing cylinders, a drive shaft mounted on said frame, and a separate drive gear meshing with each of said cylinder gears for driving each of said rotary printing cylinders and connected to said drive shaft.

4. A machine as claimed in claim 3, wherein said additional rotation means comprises a supplemental drive shaft mounted on said frame; gear means interconnected between said drive shaft and said supplemental drive shaft for imparting rotation to said supplemental drive shaft; a differential gear mechanism interconnected between said drive shaft and each of said drive gears; and means interconnected between said supplemental drive shaft and each of said differential gear mechanisms for supplying said second constant rotary movement to each of said rotary cylinders.

5. A machine as claimed in claim 1, wherein said lifting device means lift said rotary printing cylinders toward and away from said material, from a first position in contact with said material to a second position out of contact with said material.

6. A machine as claimed in claim 1, wherein said lifting device means lift said material toward and away from said rotary printing cylinders.

7. A machine as claimed in cliam 1, wherein said further additional rotation means comprises a supplemental drive shaft mounted on said frame; gear means interconnected between said driving means and said supplemental drive shaft for imparting rotation to said supplemental drive shaft; and means interconnected between said supplemental drive shaft and each of said driving means for supplying said second constant rotary movement to each of said rotary cylinders.

8. A machine as claimed in claim 1, wherein each of said lifting device means is a fluid operated pistoncylinder mechanism; and each of said digital counting means comprises an electronic counter-relay mechamsm.

Claims

1. A rotary cylinder printing machine comprising: a frame means providing a flat surface for supporting material to be printed; at least two printing devices supported on said frame means for printing said material, each of said printing devices including a rotary printing cylinder, each of said rotary printing cylinders having a first circumferentially extending printing portion and a second circumferentially extending nonprinting portion; means for moving said material over said flat surface for sequential contact and printing by the first printing portions of the rotary printing cylinders of each of said printing devices; driving means, operable by said means for moving, for continuously imparting a constant first rotary movement to the rotary printing cylinders of each of said printing devices and for thus rotating said rotary printing cylinders at a first constant rotary speed equal to the speed of said first rotary movement; lifting device means connected to each of said printing devices and to the respective adjacent portion of said flat surface for sequentially moving each of said rotary printing cylinders and the respective adjacent portion of said flat surface relative to each other, and for thus sequentially moving each of said rotary printing cylinders out of contact with said material; means operatively connected to said driving means for indicating the angular positions of rotation of said rotary printing cylinders, with respect to the respective positions of said first printing portions and second non-printing portions thereof; means positioned to detect the indication of said angular positions and to transmit impulses representative thereof; a separate digital counting means connected to said means to transmit and to each of said lifting device means for counting the number of said impulses from said means to transmit and for activating said lifting device means upon the counting of a predetermined number of said impulses, thereby moving each of said rotary printing cylinders and said material into and out of contact in a predetermined sequence dependent upon said angular position of respective of said rotary printing cylinders; and additional rotation means, connected to said driving means, for imparting an additional second constant rotary movement to each of said rotary printing cylinders only when out of contact with said material, and for thus changing the speed of rotation of each of said rotary printing cylinders to a second constant rotary speed, equal to the sum of the speeds of said first and second rotary movements, only when out of contact with said material.

8. A machine as claimed in claim 1, wherein each of said lifting device means is a fluid operated piston-cylinder mechanism; and each of said digital counting means comprises an electronic counter-relay mechanism.