Abstract:
An inker unit for a printing unit of a web-fed rotary printing press has a pair of ink application rollers in direct contact with a forme cylinder and with a central, ink receiving roller. A pair of inking rollers are also in direct contact with the ink receiving roller, and in indirect contact with the ink application rollers through riding rollers. The ink application rollers are thus inked both directly and indirectly from the ink receiving roller.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an inking system for a printing unit of a web-fed rotary printing press. The inking system uses ink application rollers that are directly inked by a central, ink conducting roller. These ink application rollers are also indirectly inked a second time by an ink roller train that originates with the central ink-conducting roller. 
     DESCRIPTION OF THE PRIOR ART 
     A prior art short inking system for a rotary printing press is known from GB-PS 18 907 and DE 195 35 266 A1. The following steps are provided in this prior art device for improving the ink application to a forme cylinder: 
     a first ink application roller has a lesser diameter than the forme cylinder, 
     a first ink transfer roller or riding roller is placed against the first ink application roller, 
     The first ink transfer roller or riding roller is in contact with a further inking system roller, 
     this further inking system roller is an inking roller which is placed against a central inking roller—in this case a riding roller, for example—, 
     wherein, in relation to the direction of rotation of the central inking roller, the further inking system roller is in contact with the central roller ahead of the first ink application roller. 
     DE 35 45 720 A1 shows a short inking system with a screen roller wherein, with non-screened full surface printing, it is intended to achieve good ink coverage. To this end, the same principle of ink application, as with the above mentioned references GB-PS 18 907 and DE 195 35 266 A1, is applied. Two ink application rollers are employed, both of which are in contact with a screen roller. Following the transfer of ink by means of the first ink application roller to a first roller, the remaining ink application is transferred to an ink application roller in accordance with the ink splitting principle. The latter than transfers the ink to the first roller. 
     An inking system with two ink application rollers, one side of which can be brought into contact with a forme cylinder, is described in U.S. Pat. No. 2,751,843. On the other side, the two ink application rollers are in contact with a central inking roller. The ink application rollers are seated in spring-loaded rockers. The ink application rollers are seated in these spring-loaded rockers so that their position can be better matched to the contour of the forme cylinder. 
     SUMMARY OF TH INVENTION 
     The object of the present invention is based on providing an inking system for a rotary printing press. 
     In accordance with the invention, this object is attained by the provision of an inking system that uses a central ink-conducting roller to supply ink to ink application rollers. Ink may be supplied in both a direct path and an indirect path from the ink-conducting roller to the ink application roller or rollers. The ink application roller or rollers may be supported for movement into and out of contact with a forme cylinder. 
     The advantages to be gained by the present invention consist in particular, in that: 
     It is possible to provide the inking system with a low structural height and with the application of chamber doctor blades or doctor blade devices directly on a central inking roller which “distributes” ink, even with a short structural length. 
     It is possible to arrange several, for example two, inking roller trains, each of which is provided with a plurality of inking rollers, from the central inking roller, each of which provide an ink application to a common forme cylinder. 
     It is possible, in a simple manner, to generate a multitude of different ink separation options by changing the contact of the inking rollers with each other, or with the central inking roller. 
     By the placement of the plurality of inking rollers in a plurality of pairs of rockers, it is possible to adjust the plurality of the inking systems easily and rapidly, in spite of the restricted spatial conditions; i.e. the very close arrangement of the inking systems and printing units. The operator can reach each roller without contortions. In a particularly advantageous manner, it is possible to pivot each inking roller train by itself in such a way that the operator practically has all of the inking rollers of the respective inking roller train “in front of his stomach”. 
     Thus, with small space requirements, it is possible to house a relatively large number of inking rollers. It is possible, by means of the selective placement of inking rollers against the central inking roller, and by means of bringing the inking rollers into and out of contact with each other, to selectively change the thickness of the ink layer to be applied to the forme cylinder. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the present invention are represented in the drawings and will be described in greater detail in what follows. Shown are in: 
     FIG. 1, a side elevation view of a schematic representation of an inking system in accordance with the present invention, which inking system has been placed against a forme cylinder and is providing a first ink flow bypass D and a second ink flow bypass E, 
     FIG. 2, a representation analogous to FIG. 1, but with an inking system with a second riding roller placed on the ink application roller, 
     FIG. 3, a representation of “work position A”, and “servicing position B”, and in 
     FIG. 4, a further preferred embodiment of an inking system in accordance with the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An inking system  1 , for example a short inking system of a rotary printing press, essentially consists of an ink application device  3 , which places an application of ink onto an ink receiving roller  2 , hereinafter called “central roller  2 ” or “roller  2 ” for short, as may be seen in FIG.  1 . If the central roller  2  is designed as a screen roller, for example, ink is transported in its small cups or hatchings. 
     In place of the screen roller, however, central rollers  2  of other construction can be employed. For example, they can be provided with a smooth plastic sheath of, for example Rilsan TM, or a different oleophilic, rubber-elastic sheath for example, known from DE 28 12 998 C2, FIG. 3, or a ceramic sheath, for example Fe 2 O 3 , or a sheath of glass. The ceramic or glass sheath can also have indentations, or can have a surface structure produced in another way. 
     The ink application device  3  can consist, for example, of a doctor blade  5 , known per se, or can also consist of several rollers, which are in contact with each other and which receive their ink application, for example, from a conventional ink reservoir or from a pump or an ink spray device, etc. It is also possible to provide several inking roller trains as the ink application device  3 . 
     One or more ink application rollers  12 ,  13  are in contact with the central roller  2 . Ink application roller  12  is part of a first inking roller train  20 . Ink application roller  13  is part of a second inking roller train  23 , all as seen in FIG.  1 . The first inking roller train  20  provides a first ink flow bypass D. The second inking roller train  25  provides a second ink flow bypass E. 
     In addition to the ink application device  3  and the ink application rollers  12 ,  13 , at least one more inking roller  16 ,  17  with an oleophilic sheath is in contact with the surface of the roller  2 . The inking rollers  16  and  17  are part of the first and second inking roller trains  20  and  25 , respectively. Inking roller or rollers  16 ,  17  can each be designed as a back-and-forth moving inking roller or rollers. The oleophilic sheath of a first riding roller  29 ,  31  is in contact with each of ink application roller(s)  12 ,  13 , respectively and also with each of the inking roller  16 ,  17  in the first and second inking roller trains  20  and  25 , respectively, as seen in FIG.  1 . The riding roller  29 ,  31  can be designed as a back-and-forth moving roller. Respectively, one second riding roller  38 ,  39  with oleophilic sheaths can also be placed on the ink application rollers  12 ,  13  of the first and second inking roller trains  20  and  25 , respectively as seen in FIG.  2 . The second tiding rollers  38 ,  39  can be engaged with, or disengaged from the respective ink application rollers  12 ,  13 . The ink application rollers  16 ,  17  can each be engaged with, or disengaged from, the central roller  2 . It is sufficient to drive the rollers  12 ,  13 ,  16 ,  17 ,  29 ,  31 ,  38 ,  39  of the first and second inking roller trains  25  and  30 , respectively by means of friction. However, they can also be driven in other ways, for example by electric drives. Each can be adjusted in respect to its adjoining rollers, or respectively to the central roller  2  to adjust the width or thickness of the ink transfer strips or layers which are applied by the first and second ink roller trains  25  and  30  to the forme cylinder  11 . 
     The upper inking system rollers  16 ,  29 ,  12  constitute the first inking roller train  20 . The lower inking system rollers  17 ,  31 ,  13  constitute the second inking roller train  25 . These two inking roller trains  20 ,  25  are each respectively supplied with ink from the central roller  2 , via each of the first inking system rollers  16 , or respectively  17 , and additionally via each of the first ink application rollers  12 , or respectively  13 . However, it is also possible to keep one or the other of the ink application rollers  12 ,  13  out of contact with the central roller  2 . In this case the ink flow would be as follows: 
     a) the upper or first inking roller train  20  from the roller  2 -&gt;the inking roller  16 -&gt;the riding roller  29 -&gt;the ink application roller  12 , and/or 
     b) the lower or second inking roller train  25  from the roller  2 -&gt;the inking roller  17 -&gt;the tiding roller  31 -&gt;the ink application roller  13 . 
     However, it would also be possible for only the upper inking roller train  20  to be switched in, and the lower inking roller train  25  to be switched off. To this end, the inking roller  16 , or respectively  17 , would have to be brought out of contact with the roller  2 . 
     Further possibilities of affecting the printing ink application to a printing forme  30  of a forme cylinder  11  via the ink application rollers  12 ,  13  include: 
     c) one of the two ink application rollers  12  or  13  is brought out of contact with the forme cylinder  11  and the central roller  2 . The following rollers remain in contact: 
       16 , or respectively  17 , with the central roller  2  and the riding roller  29 , or respectively  31 , the riding rollers  29 , or respectively  31 , with the respective ink application roller  12 , or respectively  13 , assigned to them; 
     d) as in c), but the riding roller  29 , or respectively  31 , is taken out of contact with its adjoining rollers  16  and  12 , or respectively  17  and  13 , of the roller train  17 - 31 - 13 , or respectively  16 - 29 - 12 , whose ink application roller is not placed against the forme cylinder; 
     e) the first inking rollers  16 ,  17  are placed against the central roller  2 , and the ink application rollers  12 ,  13  are placed against the forme cylinder  11 . One or both riding rollers  29 ,  31  have been brought out of contact with the adjoining rollers  16  to  12 . 
     The rollers  16 - 29 - 12 , and  38  of the two above described embodiments of the first inking roller train  20  are pivotably arranged together around the axis of rotation  10  of the central cylinder  2 . Spaced inner rockers  8 , as seen in each of FIGS. 1-4, provide support for the first inking roller train  20 . 
     The rollers  17 - 31 - 13 , and  39  of the two above described embodiments of the second inking roller train  25  are pivotably arranged together around the axis of rotation  10  of the central cylinder  2 . Spaced outer rockers  9 , as seen in FIGS. 1-4, provide support for the second inking roller train  25 . 
     The roller(s) of both inking roller trains  20 ,  25  can be pivoted from their work position A, as seen in FIG. 1 around their axis of rotation  10  away from the forme cylinder  11  so far that they move from their nearly horizontal position as seen in FIG. 1 into a nearly vertical position (S), into a servicing position S, as seen in FIG.  3 . They can be moved independently of each other and usefully sequentially. By means of this movement of each of the inking roller trains  25 ,  30  it is therefore possible to bring the rollers of one of the inking roller train  20 ,  25  into a position S defined as a servicing position, in which it is possible to adjust the position of the rollers in respect to each other and to the central roller  2 . Prior to initiating the pivoting process for each inking roller train  20  or  25 , the ink application device  3  has been removed out of the inking system  1 . Space is made available by this removal of the ink application device  3  for the temporary access to the rollers  16 ,  29 ,  12 , ( 38 ) of the first roller train  20 , or to the rollers  17 ,  31 ,  13 , ( 39 ) of the second roller train  25 , all as may be seen in FIG.  3 . 
     Following adjustment, the serviced one of the inking roller trains  25 ,  30  is pivoted back into a work position A and is fixed in place. In this position, at least one ink application roller  12 ,  13  rests against the forme cylinder  11  with the desired ink application roller strip width or thickness. By means of the just described measures, it is possible to realize an inking system  1  of low structural height and, in the case of employing chamber doctor blades, additionally also of little structural depth. 
     The rollers  16 ,  29 ,  12 , ( 38 ) of the first inking roller train  20  are rotatably seated or supported, in the two inner rockers  8 , as seen in FIG. 2, which inner rockers  8  are spaced apart from each other, and are adjustable. The two inner rockers  8  are arranged axially spaced apart from each other and are connected with each other fixed against relative rotation. They are together arranged, pivotable around the axis of rotation  10  of the roller  2  in such a way that the rollers  16 ,  29 ,  12 , ( 38 ) can move into the above described “servicing position S”. In the described preferred embodiment, the two inner rockers  8  are each pivotably seated on a bushing, which in turn is seated in bores in the lateral frames  55 . In both the work and servicing positions of the first inking roller train  20 , the rockers  8  can be locked, fixed in place in the lateral frames  55 . 
     At least one of the ink application rollers  12 ,  13  is placed against the forme cylinder  11  in the “work position A” of the two pairs of rockers  8 ,  9 . 
     In the “servicing position S”, either the inner rocker pair  8  with all its rollers  16 ,  29 ,  12 ,  38 , or the outer rocker pair  9  with all its rollers  17 ,  31 ,  13 ,  39  have been pivoted away from the cylinder  11  around the axis of rotation  10 , for example by 50°. In this “servicing position S”, as depicted in FIG. 3, all rollers of the inking roller trains  20  or  25  carried by the pivoted-away rocker pairs  8  or  9 , respectively are then practically freely accessible to an operator. This means that the rollers can be removed without obstacles from the inking system, or can be newly installed and adjusted with respect to each other. 
     Subsequently the rocker pair  8  or  9  is pivoted back into its “work position” and is locked, fixed in the lateral frame  55 . A pivot angle of better than 30° such as, for example of 45° to 180° is possible for each inking roller train  20  or  25 . 
     The rollers  17 ,  31 ,  13  and if provided, also a riding roller  39  on the ink application roller  13  of the second inking roller train  25  are rotatably seated in the two outer rockers  9 , which are axially spaced from each other and which are connected with each other, fixed against relative rotation. “Outer” means, that the outer rockers  9  are close to the lateral frame  55 . “Inner rockers  8 ” means, that these rockers  8  can be pivoted about the axis of rotation  10  between the two outer rockers  9 . 
     The above mentioned bushings, not represented, which support the inner rockers  8  and the outer rockers  9  are arranged concentrically in respect to the axis of rotation  10  and to the bores in the lateral frames  55 . The two roller journals  4  of the central, oleophilic ink receiving roller  2  are rotatably seated in these bores. The drive, for example a gear, a direct drive by an electric motor, etc. of the roller  2  takes place via one of the two roller journals  4 . The pivoting movements of both pairs of rockers  8 ,  9  can take place manually, but can also be accomplished by means of other drive mechanisms, for example gears, gear wheels, coupling gears, traction mechanism gears, etc., or other types of gears. 
     The diameter of the central roller  2  can be equal to, greater, or less than the diameter of the rollers  12 ,  16 ,  29 , or respectively  13 ,  17 ,  31 . This diameter of the central roller  2  corresponds to a not whole number multiple of the diameters of rollers  12 ,  16 ,  29 ; or  13 ,  17 ,  31 . The rollers  12 ,  16 ,  29 ; or  13 ,  17 ,  31  can all have diameters which are different from each other. 
     The two roller journals  18 ,  14 ,  21  of each of the rollers  12 ,  29 ,  16 , and possibly also of additional rollers, are arranged, displaceable and adjustable against compression springs  28 , in guides  23 ,  6 ,  26  which are oriented in the direction toward the surface of the roller  2 . The guides  23 ,  6 ,  26  are respectively provided in both of the inner rockers  8 . 
     The two roller journals  19 ,  34 ,  22  of the rollers  13 ,  31 ,  16 , and possibly of additional rollers are arranged, displaceable and adjustable in guides  24 ,  7 ,  27 , which are oriented in the direction toward the surface of the roller  2 . The guides  24 ,  7 ,  27  are respectively provided in both rockers  9  of the outer rockers. 
     Depending on whether printing is to be performed in accordance with a wet or dry offset process, a dampening system, not represented, can be provided or dispensed with. 
     In the second preferred embodiment, as depicted in FIG. 2, still another or second riding roller  38 ,  39  acting on the ink application roller  12 ,  13 , as seen in FIG. 2, is additionally in contact with each ink application roller  12 ,  13 . The roller journals  41 ,  42  of the respective second riding rollers  38 ,  39  are rotatably fastened in the respective ends of a pair of holding aims  43 , or  44 , on the rockers  8  or  9 , respectively. The second riding roller  38  or  39  is pulled, or pushed, against the surface of the ink application roller  12 ,  13  respectively by an extension or compression spring  28 . The second riding rollers  38 ,  39  have a hard, oleophilic surface of plastic or metal, for example, and can also be embodied to move axially back and forth. 
     As already mentioned above, the inking roller  16  or  17 , which is in contact with the first riding roller  29  or  31 , is arranged so it can be engaged with or disengaged from the roller  2 , as depicted in FIG.  2 . For this purpose, the roller journals  21 ,  22  of the inking rollers  16 ,  17  and the roller journals  33 ,  34  of the first riding rollers  29 ,  31  are supported in pivotable pairs of brackets  48  and  49 ; or  45  and  50 , respectively, which are brackets made of heavy plate. The roller journals  33 ,  34  are maintained in the outer ends of the pairs of brackets  45 ,  50 . The other ends of the pairs of brackets  45 ,  50  are seated in a pivotable and adjustable manner on the rockers  8 , or respectively  9 . 
     The ends of the pairs of brackets  48 ,  49  and the ends of the pairs of brackets  45 ,  50  are rotatably seated on the roller journals  33 ,  34  of the first riding rollers  29 ,  31 . 
     The pairs of brackets  45 ,  50  are each arranged so they can be finely adjusted in respect to the pivot arms  51 ,  52  by means of adjusting screws  53 ,  54 . The inking rollers  16 ,  17  are pushed by means of springs  28 —for example compression springs—against the first riding roller  29 , or respectively  31 . The first riding rollers  29 ,  31  are pushed against the surfaces of the inking rollers  16  and  12 , or respectively  17  and  13 , by means of springs  32 . The ends of the pairs of brackets  48 ,  49  which are remote from the riding rollers  29  and  31  are respectively hingedly connected with a fork head of a work cylinder  56 ,  57 . 
     The opposed bearings of the work cylinders  56 ,  57  are respectively fastened on a narrow side of the rockers  8 , or respectively  9 . 
     The inking rollers  16 , or respectively  17 , are brought out of contact with the central roller  2  by the actuation of the work cylinders  56 ,  57 . However, they remain in contact with the riding rollers  29 ,  31 , and the latter, in turn, remain in contact with the ink application rollers  12 ,  13 . The ink application roller  12  is in contact with the central roller  2 , as well as with the second riding roller  38 ,  39 , and the forme cylinder  17 , all as may be seen in FIG.  2 . 
     It is also possible to make the second riding rollers  38 ,  39  so they can be engaged with, or disengaged from the ink application rollers  12 ,  13 , which are assigned to them. 
     However, the two inking roller trains  20  and  25  can also have more than two oleophilic rollers  16 ,  12 , or respectively  17 ,  13 , which can be brought into direct contact with the surface of the central roller  2 , and more than two riding rollers  29 ,  31  per roller train can also be provided. 
     The following applies to both preferred embodiments: 
     At least one riding roller  29 ,  31  having, for example, a hard oleophilic surface, made of a plastic material, “Rilsan”, for example, is respectively pivotably arranged on the rocker  8 ,  9  between each ink application roller  12 ,  13  and the inking roller  16 ,  17 . Each riding roller  29 ,  31  is pushed, by the force of spring  32 , supported on the rockers  8 ,  9 , against the surfaces of the ink application roller  12 , or respectively  13 , and the inking roller  16 , or respectively  17  as seen in FIG.  1 . In FIG. 2, the shaft journals  33 ,  34  of the riding rollers  29 ,  31  are respectively seated on first ends of pivotably seated pivot arms  45 ,  50 . The second ends of the pivot aims  45 ,  50  are hinged to the rockers  8 ,  9 . All or some rollers of both inking roller trains  20 ,  25  can be designed to be moving back and forth axially, i.e. as distributing rollers. 
     Both pairs of rockers  8 ,  9  are seated, pivotable around the axis of rotation  10  of the ink receiving roller  2 , by means of schematically represented drives  46 ,  47  which are shown in FIG.  1 . The opposed bearings of the drives  46 ,  47  are supported on the two lateral frames  55  of the inking system  1 . Besides dual-acting work cylinders, it is also possible to employ gear motors as the drives  46 ,  47  for the pivotable pairs of rockers  8  and  9 . 
     In this case, the inner rockers  8 , or respectively the outer rockers  9 , which are rigidly connected with each other, are each equipped with a hub having a bore. The two hubs of the outer rockers  9  are rotatably seated in bores in the lateral frames  55 . The two hubs of the inner rockers  8  are seated in the two hubs of the outer rockers  9 . Respectively, one of the hubs of the inner and outer rockers  8 ,  9  is provided with teeth on the outside. These are respectively in connection, with or without traction mechanisms, with the teeth of a drive motor. 
     The roller journals  4  of the ink receiving roller  2  are rotatably and driveably seated in the bores of the hubs of the inner rockers  8 . 
     In the preferred embodiment represented in FIG. 4, the three rollers  16 ,  29 ,  12  of the first inking roller train  20  are arranged, switched “in series”, or “in line” on the rocker pair  8 . A “series flow of ink” F is created, i.e. the roller  16  is in contact with the roller  2 . The ink application roller  12  is in contact with the forme cylinder  11 . The riding roller  29  is in contact with the rollers  16  and  12 . From the roller  2  an “in series” or “in line” ink flow F results from the roller  2  to the roller  16 -&gt;via the riding roller  29 -&gt;via the ink application roller  12  and onto the forme  30  of the forme cylinder  11 . 
     Ink is brought from the central roller  2  to the second ink application roller  13  via the ink flow bypass G. For this purpose, an inking roller  59  with an oleophilic sheath is in contact with the surface of the central roller  2  and with an oleophilic sheath of a riding roller  58 . The rollers mentioned in connection with this preferred embodiment are engaged with, or disengaged from each other in the same way as described in the first preferred embodiment. The same applies to the pivotability of the pairs of rockers  8 ,  9 . 
     While preferred embodiments of an inking unit in accordance with the present invention have been set forth fully and completely herein above, it will be apparent to one of skill in the art that a number of changes in, for example the type of ink being used, the specific drive assembly for the forme cylinder and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the following claims.