US3715979A

US3715979A - Offset printing machine

Info

Publication number: US3715979A
Application number: US00053547A
Authority: US
Inventors: E Erb; W Pfeil; R Weigele; W Habiger; W Kramer
Original assignee: Fortuna Werke Maschinenfabrik GmbH
Current assignee: Fortuna Werke Maschinenfabrik GmbH
Priority date: 1970-07-09
Filing date: 1970-07-09
Publication date: 1973-02-13
Anticipated expiration: 1990-02-13

Abstract

A printing machine of the offset type in which a foil covered roller is engageable with a rubber cloth covered roller to supply printing material thereto, while an application roller engages the foil covered roller to apply printing material thereto. Both the foil covered roller and the application roller are supported for tilting movement so the foil covered roller can be moved toward and away from the rubber cloth covered roller, while the application roller can be moved toward and away from the foil covered roller. Frames supporting the foil covered and application rollers are tiltable about respective axes lying substantially in the common tangential plane of the line of contact of the respective roller and the roller relative to which it is tiltable. The machine includes a supply of printing material contained in a reservoir formed by a ductor roller and a counter roller adjustably pressed together. The ductor roller is unidirectionally driven in adjustable steps to draw printing material from the reservoir.

Description

United States Patent 1 Erb et al. Q

[ 1 Feb. '13, 1973 OFFSET PRINTING MACHINE [75] Inventors: Edgar Erb, Leitershofen; Walter Habiger, Mohringen; Willi Kramer, Zuffenhausen; Wolfgang Pfeil, Komwestheim; Reinhold Weigele, Muenchingen, all of Germany [73 Assigneei Fortuna-werlze Maschinenfalirik Aktiengesellschaft, Stuttgart-Bad Cannstatt, Pragstrasse, Germany [22] Filed: July 9, 1970 [21] Appl. No.: 53,547

Primary ExaminerJ. Reed Fisher Attorney-Walter Becker 57 ABSTRACT A printing machine of the offset type in which a foil covered roller is engageable with a rubber cloth covered roller to supply printing material thereto, while an application roller engages the foil covered roller to apply printing material thereto. Both the foil covered roller and the application roller are supported for tilting movement so the foil covered roller can be moved toward and away from the rubber cloth covered roller, while the application roller can be moved toward and away from the foil covered roller. Frames supporting the foil covered and application rollers are tiltable about respective axes lying substantially in the common tangential plane of the line of contact of the respective roller and the roller relative to which it is tiltable. The machine includes a supply of printing material contained in a reservoir formed by a ductor roller and a counter roller adjustably pressed together. The ductor roller is unidirectionally driven in adjustable steps to draw printing material from the reservoir.

10 Claims, 15 Drawing Figures PATENTEDFEB 1 3 197s 3,715,979 SHEET 2 BF 6 OFFSET PRINTING MACHINE The present invention relates to an office printing machine and more particularly to an offset printing machine including a printing mechanism with a foil cylinder, with a rubber cloth cylinder and with a counterpressure cylinder as well as a dye and humidifying mechanism with an applying roller feeding the foil cylinder. The applying roller cooperates with at least one feeding roller for a printing medium, the dye and/or humidifying fluid. The foil cylinder is adapted to be placed on and removed from the rubber cloth cylinder. The applying roller is adapted to be placed on and removed from the foil cylinder. The customary rangeof sizes'within which offset printing machines are produced, comprises among others the well-known small offset machines which with regard to the dimensions and manufacturing and servicing costs have been developed for the use in small and auxiliary plants and offices. Whereas, however, small offset machines of the above mentioned type generally require the operation by skilled personnel or at least correspondingly in- .structed personnel, the office printing machines are designed similar to customary copying machines or the like which can be operated and serviced by semi-skilled operators. For the use of office printing machines,

therefore, a considerable simplification of the adjusting, operating, and servicing operations is necessary. Such simplification however, in view of the field of use of office printing machines and the permissible costs can only to a limited extent be realized by the customary automation and a corresponding use of automatic machinery. In this respect, the customary designs of offree printing machines still require improvement.

It is, therefore, an object of the present invention to provide an office printing machine which at comparatively low structural costs and simple construction will permit a simple adjustment of the important operational factors, especially the dye and humidity control and the dyeing and printing operation in a one-way operation or in a continuous printing operation while permitting a direct checking and surveying.

This object and other objects and advantages of the invention will appear more clearly from the following specification, in connection with the accompanying drawings, in which:

FIG. I is a diagrammatic overall side view of a printing machine according to the invention with the housing wall broken out in the region of those structural elements which are of primary interest in this connection.

FIG. 2 illustrates an enlarged cutout of the side view of FIG. 1 and, more specifically, within the region of the dye mechanism with the reservoir for the dye.v

FIG. 3 is a likewise larger cutout of the side view of FIG. 1 with the humidifying mechanism,'the application roller and the holding means therefor as well as the foil cylinder and the rubber cloth cylinder.

FIG. 4 is a partial top view of the printing machine I according to the invention within the region of the laterally arranged functional elements according to FIG. 3.

FIG. 5 represents an inclined section taken along the line V-V of FIG. 3.

FIG. 6 diagrammatically illustrates the geometry of the applying roller and the journalling means for the foil cylinder.

FIG. 6a is an enlarged cutout from FIG. 6 in the range of contact of the applying roller with the humidifying roller.

FIG. 7 shows a humidity dosing device by way of a cutout of the side of FIG. 3.

FIG. 8 is a horizontal section taken along the line VIIIVIII of FIG. 7.

FIG. 9 is a partial section of the lifter roller arrangement within the dye mechanism, said section being taken along the line IX-IX of FIG. 1.

FIG. 10 is a section along the line X-X of FIG. 9 and shows the lifter roller drive.

FIG. 11 represents a horizontal section through a building group which is operatively connected with the foil cylinder drive and is adapted to be drivingly connected to the oscillatory drive of a distributor roller cooperating with the application roller.

FIG. 12 is a ductor roller drive with a loop spring clutch within the dye mechanism of the printing machine according to FIG. 1.

FIG. 13 is a vertical axial section taken along the line XIII-XIII of FIG. 12.

FIG. 14 is a modified ductor roller drive with two spring loop clutches.

The office printing machine according to the present invention is characterized primarily in that the application roller is journalled in a pivotable frame. The pivot axis thereof is, together with the axis of rotation of the feeding roller, journalled independently of said pivotable frame. The same is located in a plane which intersects the angle stroke of the axis of rotation of the application roller between the depositing and lifting-off position of said application roller with regard to the foil cylinder.

These features are not dependent on the presence of a rubber cloth cylinder which conveys the printing style or print to be effected and also not dependent on the specific prevailing factors of the surface or lithoprint. These features are principally applicable with relief printing machines which operate with corresponding relief foils or stereotype plates. Thus these features are not limited to offset printing machines. It is a matter of fact that a realization of features advantageously possible not only with offset office printing machines, but also with small offset machines and even with larger machine designs.

The design of a printing machine in conformity with the present invention brings about above all that the pressure exerted between the application roller and the humidifying roller in the adjusting phase of the dye and humidifying mechanism with the application roller lifted off the foil cylinder deviates comparatively little from the pressure which is applied during the inking up of the foil cylinder and during the subsequent printing operation, i.e. while the application roller is placed on the foil cylinder. After adjusting the dye and fluid supply or after the adjustment of the predosing of the.

dye while the application roller is still in its lifted-off position, the operator may assume that operational conditions have been set. Thus after the depositing of the application roller for inking up the foil cylinder no material changes will occur so that at best minor subsequent corrections of the dye and fluid supply are required. Thus, in conformity with the present invention, due to a certain geometric design of the respective roller bearing arrangement, i.e. practically without the use of additional devices, a considerable simplification in the servicing will be realized.

These advantages apply in particular when designing in conformity with the present invention, a printing machine in which the plane defined by the pivot axis of the pivotable frame of the application roller and by the axis of rotation of the humidifying roller at least ap-,

proximately symmetrically subdivides the angle stroke of the axis of rotation of the application roller. in this connection, also relatively high values of the angle stroke of the axis of rotation of the application roller may be admitted relative to the pressure between the application roller and the humidifying roller without having to consider deviations between the conditions of operation with deposited and lifted-off application roller.

According to a further development of the printing machine according to the invention, the pivot axis of the pivotable frame of the application roller is arranged at least approximately in the tangential plane which passes through the line of contact of the foil cylinder and the application roller in its deposited position. In other words, the pivot axis is located in a common tangential plane with regard to the application roller and the foil cylinder. Consideration is to be given the flattening of the generally elastic mantle of the application roller during its pressing against the foil cylinder. Accordingly the above mentioned line of contact is replaced by the center line of the contacting surface extending in the direction of the length of the roller. The resulting geometric mounting conditions make it possible advantageously precisely radially to deposit and lift the application roller with regard to the circumferential surface of the foil cylinder. Consequently, in particular, also with elastically deformable mantle of the application roller, lubricating and wiper phenomena are avoided.

Expediently, for the pivotable frame of the application roller, there is provided a positive support. This support determines the spacing between the axis of rotation of the application roller in its depositing position with regard to the foil cylinder, and the axis of rotation of the foil cylinder in its depositing position with regard to the rubber cloth-cylinder. The said positive support may be in the form of adjustable abutments engaging the two bearing sides of the pivotable frame. A support of the pivotable frame exists in cooperation with a corresponding pressing of a spring against the foil cylinder with the applying roller deposited. Such a support of the pivotable frame makes it possible to adjust a fixed axial distance which is independent of the elasticity of the roller mantle. This distance is a width of the flattening zone of the depositing.roller. This width is likewise independent of the elasticity of the roller mantle.

This has proved advantageous for maintenance of constant conditions of operation for long time periods and thereby has greatly facilitated the operation of the device.

'The arrangement of thepivotable axis of the applying roller mounting in conformity with the present invention can correspondingly and advantageously also be applied to the holding means for the foil cylinder. The holding means are necessary for lifting and depositing the foil cylinder with regard to the rubber cloth cylinder. With such printing machine likewise forming a part of the present invention, the foil cylinder is journalled in a pivotable holding means. The pivot axis of the holding means is located in one plane with the axis of rotation of the application roller in its deposited position with regard to the foil cylinder. The application roller intersects the angle stroke of the axis of rotation of the foil cylinder between its depositing and lifted-off position. Also, in this instance, it is again particularly advantageous if the plane determined by the pivot axis of the pivot mounting of the foil cylinder and by the axis of rotation of the application roller occupying its deposited position subdivides the angle stroke of the axis of rotation of the foil cylinder at least approximately symmetrically. In this way, it will be realized that between the application roller occupying its deposited position and the foil cylinder, as well as with a foil cylinder lifted off the rubber cloth cylinder or deposited thereon, i.e. during the inking of the foil as well as during the printing operation there exists a nonmaterially different or at least approximately corresponding pressing pressure. The operator therefore can assume that the transmitting conditions of the dyefluid mixture as they were set during the inking-up of the foil, from the application roller to the foil cylinder will not undergo any material changes when depositingsaid foil cylinder upon the rubber cloth cylinder.

Also the remaining features of the invention which concern the geometric conditions of the application roller-pivotal mounting means can to a major extent and with the same advantages be applied to the pivotal holding means for the foil cylinder. In particular, expediently, there is assured of a radial depositing and lifting movement of the foil cylinder with regard to the rubber cloth cylinder.

Correspondingly, the pivot axis of the pivotal mounting of the foil cylinder is arranged at least approximately in the tangential plane which passes through the line of contact (or the center line of the contacting surface) of the rubber cloth cylinder and the foil cylinder in its deposited position being on the rubber cloth cylinder.

The dye mechanism of office printing machines of the above mentioned type generally comprises a transversely movable lifting roller equipped with an oscillating drive. The lifting roller in the course of its oscillating movement alternately engages a dye-supplying ductor roller and a conveying dye roller. Such lifter roller operates in cooperation with a stepwise rotating ductor roller adjustable with regard to the rotatable stroke. This accordingly makes it possible to convey a precisely determinable amount of dye to the conveying elements of the dye mechanism and thereby to the application roller. Also, in this instance, within the framework of the present invention there exists the possibility of simplifying the servicing and construction. To this end, the oscillating drive of the lifter roller comprises at least one resilient coupling member which connects an oscillating driving member to a holding means. This carries the lifter roller mounting and is movable in conformity with the oscillating stroke of the lifter roller. The holding means is adjustable with regard to its relative adjustment relative to the driving member. In view of the resilient coupling member within the oscillating drive of the lifter roller in combination with the relative adjustment between the mounting means and the driving member there is obtained a particularly simple possibility of effecting an adjustment. The engaging period of the lifter roller is affected with the ductor roller on one hand, and with the conveying dye roller on the other hand, while the resilient coupling member is correspondingly deformed. Generally one adjustment during the assembly of the printing machine is necessary, and at best only an occasional subsequent adjustment will be necessary.

The last mentioned design may expediently be further developed in such a way as described by thefollowing. As holding means or mounting for the lifter roller there are provided two oscillating filters which are interconnected by a coupling shaft and which are connected with the oscillating driving member by way of a resilient coupling arm. The mentioned adjustment of the engaging periods of the lifter roller can be realized in a particularly simple manner. This adjustment occurs by displacing the oscillating stroke, for instance by reducing or extending the oscillating driving member or by deforming the resilient coupling arm by means of corresponding tools during the assembly. In particular, it has proved expedient to journal the oscillating lever for free rotation on the coupling shaft and to connect said oscillating lever with said coupling shaft by resilient followers. This design has the advantage that the resilient follower will compensate for alignment tolerances between the ductor roller and the conveying dye rollers. Accordingly a proper engagement of the lifter roller with these two rollers will be assured. In this way, not only the assembly but also the servicing of the machine during the operation will be simplified inasmuch as corresponding adjusting and post-adjusting operations are not necessary. The foregoing fact is of particular importance with the general object underlying the present invention.

In connection withthe dosing of the dye at the ductor roller, the customary stepwise turning drive has been mentioned. Also in this connection the invention comprises an advantageous arrangement for reducing the construction costs for office printing machines. According to this arrangement, the rotary drive of the ductor roller includes an oscillating driving member. This driving member is connected through a rotation independent effective loop spring coupling to the shaft of the ductor roller. Numerous thorough tests have proved that such a direct coupling which acts only frictionally will in view of the servo-effect of the loop spring in spite of a considerably simpler construction and lower manufacturing costs operate as reliably as the positively acting pawl ratchet mechanisms or the like customarily employed for the drive of the ductor roller. 1

Referring now to the drawings in detail, the offset printing machine illustrated in FIG. 1 comprises a printing mechanism 1 with a foil cylinder 100, a rubber cloth cylinder 120, and a counterpressure cylinder 130, as well asa humidifying device 200 and a dyeing device 300. The dyeing and humidifying device havea common starting element in the form of an application roller 60 on which the printing dye furnished by the dyeing device and the humidifying fluid furnished by the humidifying device'are brought together and which pivotable handles 11, 13, the foil cylinder 100 may with regard to the rubber cloth cylinder 120 or the application roller 60 with regard to foil cylinder 100 be.

brought into an engaging and into a lifted-off position. Of the remaining structural elements of the printing machine as they are of interest in connection with the present invention there may be mentioned only the paper feeding device 2 diagrammatically shown in FIG. 1. Included therewith are the stacking table, for instance an ascending table 3 protruding beyond the rearward housing wall, a drive control device with switch 4 and a sheet deposit station 5. The sheet deposit station 5 receives the printed sheets or foils passing between the rubber cloth cylinder 120 and the counterpressure cylinder 130.

There may first be described the design and arrangement of the application roller 60 which is important for the cooperation of the dye and humidifying devices on one hand and with the printing mechanism on the other hand.

As will be seen from FIGS. 3 5, the

bearing

62 and 68 on both sides of the application roller 60 are arranged in a pivotal frame 20 with a pivot shaft 21 which may be fixedly connected to the framework and which extends parallel to the axis of rotation 61 of the application roller 60. The pivotal frame 20 comprises two

arms

22 and 28 arranged at each end of the roller 60 and being plate-shaped while extending parallel to the lateral housing walls. Both

arms

22 and 28 are, as will be seen from FIG. 3 with regard to arm 22, provided with two slots 23 which are open toward the top and the central plane M of which is inclined toward the vertical plane and is arranged in spaced relationship to the pivot shank 2-1 of the pivotal frame 20. Each of the

arms

22 and 28 is provided with an adjustable holding jaw 26 which is connected to the pertaining arm by means of an adjusting eccentric 25 and extends parallelv to the central plane M of the slots. Jaw 26 in its turn is likewise provided with a slot-like recess 24 which ex-- tends substantially rectangularly with regard to the pertaining slot23. The

bearings

62 and 68 of the

arms

22, 28 are inserted into slots 23 and recesses 24 crossing each other so that the location of the axis of rotation 61 of the application roller can be adjusted by means of the adjusting eccentric 25 on both arms. This may be effected independently of the angular position of the pivotal frame 20 an thus independently of the application roller axis 61 and the pivot shaft 21.

The depositing and lifting off of the application roller 60 with regard to the foil cylinder is effected by an angular adjustment of the entire pivotal frame 20 about the pivot shaft 21. This is effected by means of corresponding positive supports in the form of elbow lever transmissions respectively associated with said arms and comprising

lever members

73 and 74. The corresponding lower lever members 74 are non-rotatably interconnected by a coupling shaft 71 extending over the width of the roller 60. These elbow lever transmissions form the reversing device 12 diagrammatically illustrated in FIG. 1 for setting down and lifting off the application roller onto and from the foil cylinder 100. The pivotal handle 13 is mounted on the coupling shaft 71 and is adapted to effect a uniform actuation of the two elbow lever transmissions, Le. a pivoting of the two arms 22 and 28'by the same angle for each arm and thereby makes possible a parallel displacement of the axis of rotation 61 in the depositing and lifting-off movement respectively of the application roller 60. The depositing position of the application roller with regard to the foil cylinder is, in the case of the example shown, determined not by the mutual pressing of the roller surfaces against each other, but by means of special adjusting abutments. More specifically, this is determined by means of adjusting eccentrics 72 respectively associated with the elbow lever transmissions and located on the side walls of the machine frame. In the deposited or set-down position of said application roller, corresponding abutments 75 of the lever member 73 rest against said eccentric 72.

, FIG. 6 illustrates the geometric conditions of the roller mounting while the pivotal frame of the application roller mounting is indicated by the radius between the pivot shaft 21 and the axis of rotation of the application roller 61. In the deposited position x as I also in the lifted-off position y with regard to the foil cylinder 100 which is in the deposited position relative to the rubber cloth cylinder 120, the application roller 60 contacts a preceding feeding roller, and in the specific instance shown with a humidifying roller 40. Between these two positions there is indicated the angle stroke S, which in the particular instance shown issymmetrically subdivided by the plane A extending through the axis of pivot shaft 21 and the axis of rotation 41. This condition, however, is, in view of the soft elastic property at least of one of the roller mantles, especially of the application roller and, if desired, also of the humidifying roller, not mandatory for maintaining contact between the application roller 60 and the humidifying roller 40 in both positions of the application roller. Principally, for instance, also a non-symmetric subdivision of the angle stroke S, by the plane A would be possible as is indicated, for instance, in FIG. 6 by the lifted-off position y, of the pivotal frame 20. In this instance, for instance of the lifted-off position of the application roller at a shorter distance with regard to the symmetric subdivision, of the contact area between application roller and humidifying roller there would appear a stronger mutual pressing and flattening of the two roller mantles. Such nonsymmetric arrangement may, under certain circumstances, be employed for structural reasons or in view of the fact that in both positions a different pressure is desired. Generally, however, it is advantageous in both positions to create an identical pressure so that when depositing the application roller there will occur no change in the transmission conditions between the humidifying roller and the application roller. By a corresponding adjustment of the two pivotal positions by means of the above mentioned positive supports, it is possible to compensate for such changes in the conditions of transmission.

Furthermore, FIG. 6 indicates the arrangement of the pivot shaft 21 in a common tangential plane of the application roller 60 and the foil cylinder 100 and, more specifically, in the tangential plane T, along the line of contact (or along the center line of contacting surfaces) of the application roller and the foil cylinder. The foregoing conditions pertain'for-the foil cylinder placed on the rubber cloth cylinder 120 and the application roller placed upon the foil cylinder. In this way a radial liftingoff of the application roller from the foil cylinder in depositing position will be realized. If the lifting off of the application roller is, during operation, to be carried out primarily with the foil cylinder in lifted-off position, it may be advantageous to arrange the pivot shaft 21 so that it is located in a tangential plane through the line of contact between the application roller and the lifted-off foil cylinder.

Generally, it is advantageous to realize a central position of the tangential plane T, between the two mentioned extreme instances as indicated in FIG. 6. by the dash line 2. The dash line w corresponds to the position of the tangential plane T, with the foil cylinder in liftedoff position.

In FIG. 6a, there are indicated the contacting and I pressing zones of different widths b, and b between the application roller and the humidifying roller with liftedoff y, and deposited x application roller as the situation occurs with a non-symmetric subdivision of the angle stroke S, by the plane A.

As shown in FIG. 3, the foil cylinder 100 is likewise pivotally mounted and, more specifically, by pivotal holding means 110 with the pivot axis 111 thereof. These holding means comprise two lateral supporting

levers

112 and 113 in which the axis of rotation 101 of the foil cylinder is determined by corresponding bearings. Similar to the mounting for the application roller, a positive support in the form of a lever transmission 170 with coupling shaft 171 and abutment eccentric 172 is provided for the two supporting

levers

112, 113. The abutment eccentric 172 is separately adjustable for both roller ends and determines the depositing position of the foil cylinder with regard to the rubber cloth cylinder 120, Le. the distance between the axis of rotation 101 of the foil cylinder and the axis of rotation 121 of the rubber cloth cylinder. By means of a tension spring 173, the supporting

levers

112, 113 are biased in the direction toward the two end positions of the elbow lever transmission. When the foil cylinder is in its deposited or engaging position, an abutment element 174 of the supporting

lever

112, 113 rests under the preload of said spring against a pertaining abutment eccentric 172. The elbow lever transmissions 170 form the reversing device 10 diagrammatically shown in FIG. 1. The handle means 11 are mounted on the coupling shaft 171 and make possible the adjustment of position 2: determines a plane B. This plane B subdivides the angle stroke S in the specific example in a symmetric manner and is located in a tangential plane S, extending through the contact line of foil cylinder and the rubber cloth cylinder 120.

For a non-symmetric arrangement, if desired corresponding considerations apply with regard to the transmission conditions between the application roller and the foil cylinder as they have been discussed for the transmission between humidifying roller and application roller in connection with the mounting of the application roller. Accordingly, when the application roller is deposited or in its engaging position, it may be advantageous to establish on one hand with the foil cylinder deposited relative to the rubber cloth cylinder and on the other hand with the foil cylinder lifted off with regard to the rubber foil cylinder, different pressing pressure by establishing corresponding assymetry of the angle stroke S More generally symmetrical conditions are advantageous. At any rate, however, it is important that the assymetry of the angle stroke will not be of such a magnitude that the planes A and B no longer intersect the pertaining angle stroke 8,, S respectively because this may cause operational disturbances, particularly with larger angle strokes The humidifying roller 40 cooperating with the application roller 60 together with an immersion roller 240 and with a dosing device 210 (FIGS. 7 and 8) forms the humidifying device 200 of the printing machine. The immersion roller 240 picks up the humidifying fluid from a reservoir 205 and conveys the same to the humidifying roller 40. Important for a proper cooperation with the reversible application roller is a frame connected mounting of the humidifying roller 40 which keeps the variable pressure exerted by the immersion roller away from the application roller. The variable pressure between immersion and humidifying roller is employed as control factor for the dosing of the humidifying fluid. Pressure can be raised to such an extent that the supply of humidity is interrupted by squeezing off the film between the humidifying and the immersing roller.

The device 210 for dosing the humidifying fluid comprises (FIGS. 7 and 8) two

pivotal levers

230 and 232 which are nonrotatably connected to each other by a coupling shaft 231 extending over the width of the roller. The coupling shaft 231 furthermore serves as axisof rotation for two

arms

234 and 236 which are freely rotatably mounted on shaft 231. The ends of the arms 234 have connected thereto end

bearings

242 and 243 of the immersion roller 240. These supporting arms have their lower ends rest by adjustable pressure spring means 235, 237 on pertaining

pivotal levers

230, 232. The front lever 230 has an upwardly extended arm engaged by an adjusting device 245.

The adjusting device245 comprises a two-arm cam lever 246 which is adjustable about a pivot shaft 249 connected to the framework. The lower arm of said lever 246 has a pressure element 247 for engagement in an upwardly curved or concave circular cam path 248 of the front pivot lever 230'andsupports said lever 230 in different pivoted positions in conformity with the position of the cam lever 246. In view of a self-locking effect between the member 247 and the cam path 248, these adjustments are held mechanically stabile. These pivot positions are, by actuation, directly entered into the cam lever 246. Depending on the pivot position, the

levers

230 and 232 exert a different pressing force upon the immersion roller bearings while the pressure between the immersion and the humidifying roller in view of a separate adjustment of the

pressure spring arrangement

235 and 237 is uniformly distributed over the length of the roller.

The

arms

22 and 28 are extended beyond the bearing areas of the application roller 60 toward the left (FIG. 3) and form a common pivotable frame for a roller arrangement. The latter, in addition to the application roller, also comprisesa distributing roller 55 cooperating with said application roller, and a dye roller 50 preceding said distributing roller 55. The end bearings on both sides of the distributing roller and of the dye roller are inserted in

recesses

52, 57. These recesses are open toward'the top and pertain to the

arms

22 and 28. The end bearings are detachably secured in said arms by spring clamps 53, 58. In this way, without removing the pivotal frame from .the machine housing, it is possible after detaching the spring clamps, easily to remove the rollers for carrying out servicing operations thereon.

The pivotal frame 20 is preloaded by means of tension springs 30 engaging the

arms

22 and 28 with regard to the pivot shaft 21 so as to bias said frame 20 in counterclockwise direction, i.e. in the direction for placing the application roller upon the foil cylinder. As a result thereof, also the elbow levers at their upper lever members 73 through pivot joints 76 connected to the

arms

22, 28, are preloaded or biased in the direction toward the respective elbow lever end positions. I

As indicated in FIG. 3 in dot-dash lines, the axes of rotation of the rollers journalled in the

arms

22 and 28, namely, the axis of rotation 51 of the dye roller 50 and the axis of rotation 56 of the distributing roller 55 as well as the axis of rotation 61 of the. application roller 60 form an obtuse triangle with regard to the axis of rotation 56 and, more specifically, in a transverse plane of the roller.

This arrangement brings about that an elbow lever effect occurs with a corresponding amplifying effect for pressing the distributing roller against the two other rollers. Consequently, the required pressure between the said rollers can be furnished by the relatively weak effect of the spring clamps 58 through the intervention of the bearings for the distributing roller 55. This represents a considerable simplification in the construction. The bearings of the distributing roller are to this end with corresponding play inserted in the longitudinal direction of the pertaining slot-shaped recesses of the

arms

22 and 28.

The distributing roller 55 is axially displace'ably arranged in its end bearings and is coupled to-an axially effective oscillating drive 400 as shown in FIG. 11. This drive 400 comprises an axial pressure lever 408 which is parallel to the side wall of the housing and pivotable about a vertical axis 401. The lever 406 by means of an arm through the intervention of a rotary coupling 407 engages the shaft of the distributing roller 55 and with its other arm through a roller 408 and under the effect of a spring 409 rests on the end face of a rotary driven axial cam 405. This cam 405 is driven directly by the foil cylinder to the shaft of which the axial cam 405 is connected. This driving device has not only the advantage of great simplicity and considerable saving in structural elements. In view of the fact that the spring 409 is connected to the machine frame and in view of the corresponding exertion of axial pressure upon the foil cylinder shaft there is brought about a compensation of the play for the foil cylinder inasmuch as the latter, in view of thepressing force is held in a definite axial engaging position. This arrangement permits in a simple manner a precise maintaining of the axial association of foil cylinder or printing form on one hand and rubber cloth cylinder and foil to be printed upon on the other hand.

The further structure of the dye mechanism will be seen from FIG. 2 and, in particular, from FIGS. 9, 10, 12 and 13. According to the showing, a ductor roller 310 with the counter roller 320 is mounted at the rearward housing end, said

rollers

310 and 320 being adapted to roll upon each other and at their top side to form a bite or inlet angle serving as dye reservoir. This angle or dye reservoir is laterally sealed by closure discs 322 connected to the counter roller 320. The counter roller 320 is equipped with a resilient pressing device 330 engaging the two end bearings of roller 320, and with manually operable setting screws 335.

In this way the mutual pressure between the ductor roller and the counter roller can be adjusted, i.e. the thickness of the dye film which is formed at the surface of the ductor roller and is passed downwardly from the dye reservoir. By means of the said screws provided for both roller ends, it is possible also to control the'distribution of the thickness of the dye film in the longitudinal direction of the roller. The adjustment of the dye film on the ductor roller thus makes it possible in a simple manner to provide a pre-dosing of the dye supply. For further conveying the dye between the ductor roller 310 and the dye roller 50 there is provided (FIGS. 1, 9 and 10) a transversely movable lifter roller 350 which is adapted to carry out a pendulum movement about a coupling shaft 365, said lifter roller being equipped with an oscillating ar-m drive. This roller 350 is adapted in the course of its oscillating movement alternately rollingly to engage the ductor roller 310 and the dye roller 50 respectively. For holding the lifter roller, there are at both roller ends provided

oscillating levers

380 and 385 which are freely rotatably mounted on the coupling shaft 365 (FIG. 9).

End bearings

352, 354 for the lifter roller are provided on said

oscillating levers

380 and 385. Oscillating levers 380 and 385 by way of resilient followers, for instance

simple spring elements

390 and 395, are connected to the coupling shaft 365 The coupling shaft itself as shown in FIG. 10, is connected through a resilient coupling arm 360 with respect to an oscillating driving member such as the pushrod 370 adapted to oscillate in its longitudinal direction. This pushrod may, in any standard manner, by means of a simple crank guide or the like, be put in motion.

The mentioned spring elements within the oscillating drive of the lifter roller with a correspondingly dimensioned total oscillating stroke of the driving member while simultaneously deforming said spring element make it possible to permit a certain engaging period between the lifter roller and the ductor roller on one hand and the dye roller 50 on the other hand in the'two oscillating end positions. This engagement period may be a rotary adjustment of the

oscillating lever

380, 385 relative to the coupling shaft or may be a rotary adjustment of the latter with regard to the coupling arm 360.

If desired also by a stroke displacement, for instance by shortening or lengthening the driving member 370, there may be adjusted in an opposite sense with regard to the ductor roller and the dye roller. A simple adjusting possibility is obtained by the deformation of the spring elements, for instance the coupling arms 360 by means 'of suitable tools during the assembly of the printing machine.

Such step is particularly suitable for the setting of the transmission ratios between ductor roller 310 and dye roller 50 in the plant.

The fine'dosing of the feed supply is effected .by a step-rotary drive 500 for the ductor roller 310. To this end, and in conformity with the present invention, there is provided a loop spring coupling 520 which is adapted to place the shaft 311 of the ductor roller into frictional connection independently of the direction of rotation; through an input oscillating member 540 with an oscillating driving member 510. The member 540, in

the particular embodiment shown, is designed as onearm lever which by means of a sleeve 514 is freely rotatably mounted on a stud 512 of the ductor roller shaft 311 and has its arm section 542 provided with an axial pin 516. The loop spring proper extendson one hand over an end section 311a of the ductor roller and on the other hand over the adjacent end section of sleeve 514. When these two parts move relative to each other in either direction of rotation, due to the considerable total looping angle, a friction servo-effect is produced which practically leads to an absolutely safe frictional arresting between the ductor roller shaft and the input oscillating member, but with opposite relative rotation causes only a slight friction engagement.

By means of a storage spring 550, the axial pin 516 is stationarily secured to the housing pre-loaded in the direction of the arrow P of FIGS. 12 and 13; The driving member 510, in the particular example shown, an oscillating connecting rod, engages the axial pin 516 by means of long stroke pin-slot connection 530. Furthermore, thereis provided an abutment member '560 which is pivotable and adjustable about the axis of rotation of the ductor roller shaft 312 and has a handle 562 protruding beyond the top side of thehousing. This abutment member 560, depending on its pivoting position engages the axial pin 516 by means of an abutment edge 564. The axial pin during its return stroke and under the influence of the storage spring ,550 occupies a certain position. In this way, the abutment pin, depending on the structurally determined direction of rotation of the ductor roller, determines the start or the end of the rotational strokeof the ductor roller. The driving member 510 through the intervention of the pin-slot coupling 530 moves the axial pm 516 and thereby brings the input oscillating member 540 into its oscillating output position while the storage spring 550 is tensioned. By adjusting the abutment member 560, it is possible in a simple manner to vary the rotational stroke of the ductor roller.

According to the modified stepwise rotary drive 600 of FIG. 14, there is provided a first loop spring coupling 640 and a second loop spring coupling 670. The spring coupling 620 corresponds as far as its effect is concerned to the above discussed embodiment and independently of the direction of rotation connects an input said shaft 311. Furthermore, in conformity with the input oscillating member 640 there is provided an axial pin 616 which is engaged by an oscillating driving member 610 with a pin-slot connection 630 and a storage spring 650. The arrangement furthermore com prises a counter bearing member 660 which corresponds to the abutment member 560 and is rotatably arranged on the end section 311 while being pivotally adjustable. The member 660 engages the axial pin 616 by abutment means 665 and determines the start and the end of the rotary stroke of the ductor roller.

In contradistinction to the previously described stepwise rotary drive, the said drive according to FIG. 14 has the counter bearing member 660 connected to a step 31 lb of the ductor roller shaft by the second loop spring coupling 670 in the same direction of rotation as the first loop spring coupling 620. When the loop spring coupling 620 is in its blocking position, the second loop spring coupling 670 is acted upon by the rotating ductor roller shaft with inverse power flow direction. This means according to FIG. 14, from left to right or from the step of the ductor roller shaft 31 lb to the counter bearing member 660, and therefore it is disengaged in effect. This means that it offers the rotary movement of the ductor roller shaft during the forward oscillating stroke only a slight frictional resistance. During the return stroke, the second loop spring coupling 670 is thus blocked and consequently secures the ductor roller shaft against an undesired rotation in the return direction, which in view of the low frictional connection could now occur in the now detached disengaged first loop spring coupling. Furthermore, the second loop spring coupling 670 will, with a pivoting movement of the counter bearing member 660 in forward direction of rotation of the ductor roller, occupy a blocking position, whereas the first loop spring coupling is simultaneously disengaged. Consequently, there is obtained the advantageous possibility of being able manually to rotate the ductor roller by means of the member 660 even when a stepwise drive with loop spring couplings is effected. In this way, it is possible by reciprocating the counter bearing member, to convey for a short period and independently of the adjusted conveying speed or even a standstill of the machine, additional quantities of dye from the storage container to the discharge side of the ductor roller.

It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawings, but also comprises any modifications within the scope of the appended claims.

What is claimed is:

1. An offset printing machine, having a rubber cloth cylinder adapted to print subject matter on paper or the like feeding through the machine and a foil cylinder for supplying the subject matter .in the form of printing medium to said rubber cloth cylinder and an application roller for applying the printing medium to said foil cylinder and at least one feeding roller for supplying printing medium to said application roller and a humidifying roller for supplying humidifying fluid always in engagement against said application roller means for mounting said foil cylinder in a first supporting frame, means for mounting said first frame with said foil cylinder for movement between a first position of engagement with said rubber cloth cylinder and a second position of nonengagemnt with said rubber cloth cylinder and a second frame with means thereon for supporting said application roller and at least the said feeding roller a pivot axis about which said second frame is tiltable and located in a plane containing the axis of the humidifying roller, means for mounton respectively opposite sides of said plane and for holding said application roller in contact with said humidifying roller in both the first and second position of said second frame.

2. A printing machine according to claim 1, in which said plane containing the axis of said humidifying roller and the said pivot axis of said second frame divides the angle formed by connecting lines of the said pivot axis and the axis of said application roller in both its posi-.

tions substantially symmetrically.

3. A printing machine'according to claim 1, in which the said pivot axis of one said frame is disposed substantially in the tangential plane of said foil cylinder which contains the line of contact of said application roller with said second foil cylinder.

4. A printing machine according to claim 1, in which said second frame comprises an arm at each end of said application roller, support means engageable with said arms to support the arms in one tilted position of said frame, and a coupling member fixedly connecting the said support means at opposite ends of said second frame together.

5. A printing machine according to claim 1, in which said second frame comprises an arm at each end of said application roller, each said arm having a slot extending generally parallel to said plane, said application roller having a shaft received in said slots, a holding jaw pivoted on each arm and each having a notch extending angularly to the respective slot and engageable with said shaft to hold said application roller in place in said slots, and means for adjusting said holding jaws on said arms to adjust the position of the axis of said application roller along said slots in said arms of said second frame.

resilient engagement with said application roller, a

further roller in said second frame engaging said feeding roller, the axes of said application 'roller and said feeding roller and said further roller being located at the apices of a triangle, which has an obtuse angle at that apex at which the axisof said feeding roller is located.

8. A printing machine according to claim 1, which includes said first frame supporting said foil cylinder, pivot means for said first frame, said first frame having first and second tilted positions about said pivot means corresponding to said first and second positions, respectively, of said foil cylinder, said pivot means being located in a second plane containing the axis of said application roller when in its said first position, and the axis of said foil cylinder being disposed on respectively'opposite sides of said second plane in the said first and second positions thereof.

Claims

1. An offset printing machine, having a rubber cloth cylinder adapted to print subject matter on paper or the like feeding through the machine and a foil cylinder for supplying the subject matter in the form of printing medium to said rubber cloth cylinder and an application roller for applying the printing medium to said foil cylinder and at least one feeding roller for supplying printing medium to said application roller and a humidifying roller for supplying humidifying fluid always in engagement against said application roller , means for mounting said foil cylinder in a first supporting frame, means for mounting said first frame with said foil cylinder for movement between a first position of engagement with said rubber cloth cylinder and a second position of nonengagemnt with said rubber cloth cylinder , and a second frame with means thereon for supporting said application roller and at least the said feeding roller , a pivot axis about which said second frame is tiltable and located in a plane containing the axis of the humidifying roller, means for mounting said humidifying roller in said printing machine, means for mounting said application roller on said second frame with the axis of said application roller being at least approximately between said pivot axis of the second frame and said humidifying axis, means for moving said second frame about said pivot axis for displacing said application roller for movement in a first position of engagement with said foil cylinder and a second position of nonengagement with said foil cylinder for thus disposing said application roller axis on respectively opposite sides of said plane and for holding said application roller in contact with said humidifying roller in both the first and second position of said second frame.

2. A printing machine according to claim 1, in which said plane containing the axis of said humidifying roller and the said pivot axis of said second frame divides the angle formed by connecting lines of the said pivot axis and the axis of said application roller in both its positions substantially symmetrically.

3. A printing machine according to claim 1, in which the said pivot axis of one said frame is disposed substantially in the tangential plane of said foil cylinder which contains the line of contact of said application roller with said second foil cylinder.

6. A printing machine according to claim 1, in which said second frame comprises an arm at each end of said application roller, notches formed in said arms, said feeding roller having a shaft seated in the said notches, and spring means releasably holding the said shaft of said feeding roller in the said notches in said arms.

7. A printing machine according to claim 6, in which said spring means biases said feeding roller into resilient engagement with said application roller, a further roller in said second frame engaging said feeding roller, the axes of said application roller and said feeding roller and said further roller being located at the apices of a triangle, which has an obtuse angle at that apex at which the axis of said feeding roller is located.

8. A printing machine according to claim 1, which includes said first frame supporting said foil cylinder, pivot means for said first frame, said first frame having first and second tilted positions about said pivot means corresponding to said first and second positions, respectively, of said foil cylinder, said pivot means being located in a second plane containing the axis of said application roller when in its said first position, and the axis of said foil cylinder being disposed on respectively opposite sides of said second plane in the said first and second positions thereof.

9. A printing machine according to claim 8, in which a line joining said pivot means and the axis of said foil cylinder makes substantially equal angles with said second plane in the said first and second positions of said first frame and foil cylinder.