Abstract:
A device for cleaning a roller in a rotary printing press uses a plurality of rotating brushes. Spray nozzles are arranged centrally in each of these rotating brushes. The brushes are supported on a carriage that can be moved along the length of the roller which is to be cleaned.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device for cleaning a roller of a rotary printing press. At least one rotating cleaning element, whose axis of rotation is not parallel with the axis of rotation of the roller to be cleaned, is arranged adjacent that roller. Several cleaning elements, having opposite directions of rotation, can be used. 
     DESCRIPTION OF THE PRIOR ART 
     A device for cleaning rollers is known from EP 0 693 378 B1. A brush roller is guided along the roller to be cleaned, and a cleaning fluid is simultaneously introduced into the inlet gap between the two rollers. This prior art device contains a reservoir for cleaning fluid and a catch basin for dirt particles to be removed. 
     A printing plate cleaning device is known from U.S. Pat. No. 5,148,746. A rotatable brush, in the shape of a truncated cone, and which can be moistened on the exterior, can be placed obliquely, i.e. at an acute angle in respect to the radial direction, against the plate cylinder, so that only a portion of the brush is in contact with the plate surface. In addition, the edge zone of the brush is beveled in such a way that a section of the brush in the shape of an arc of a circle can be brought into contact with the plate surface. 
     EP 0 747 217 A2 discloses a cleaning device for cylinders of printing presses. Two rotating brushes, which are offset in respect to each other in the circumferential direction of the cylinder, are provided. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is based on providing a device for cleaning a roller of a rotary printing press. 
     In accordance with the present invention, this object is attained by using several rotating cleaning elements to clean the roller. These rotating cleaning elements each have an axis of rotation that is not parallel with the axis of rotation of the roller to be cleaned. The several rotating cleaning elements may have opposite directions of rotation with respect to each other. 
     The advantages which can be obtained by the present invention rest, in particular, in that an evenly cleaned surface of the rollers or cylinders is obtained. Accumulations of ink or dirt are mechanically removed, except for a thin layer, during either running or standstill of the press. In case of intense soiling, it is possible to apply a cleaning fluid, and the rollers can also be additionally cleaned by the rotating brushes. 
     Furthermore, it is advantageous, in connection with the present invention, that it is possible to apply an ink separating agent shortly prior to the start of printing. The creation of paper waste, which must be disposed of as special waste, is prevented by use of the cleaning device in accordance with the present invention. Moreover, by removing or preventing the accumulation of dirt on the roller, which roller may be, for example a paper guide roller, the creation of creases in the paper web is prevented. 
     Finally, it is also advantageous that a paper guide roller, which cannot be driven, can be brought to the required circumferential speed by the auxiliary drive mechanism, for example prior to drawing in a paper web. 
    
    
     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 top plan view on the device for cleaning a roller in accordance with the present invention in a schematic representation, without the housing and carriage guide, 
     FIG. 2, a section II—II through the device in accordance with FIG. 1, but showing a paper web and carriage guide, as well as the section rotated by 90°, and in 
     FIG. 3, a top view of a paper guide roller with a device arranged thereon in the position of rest in a schematic representation with a paper web guide differing from FIG.  2 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A device  01  for cleaning a roller  04 , or a cylinder or the like, is arranged in the immediate vicinity of a guide roller  04  that is seated between two lateral frames  02 ,  03 , as seen in FIG.  3 . Roller  04  may be, for example, a paper guide roller  04 , having an axis of rotation  05 . The roller cleaning device  01  consists of a carriage guide  06 , which is arranged axis-parallel with the paper guide roller  04  and is fixed in place in the lateral frames. Carriage guide  06  receives a carriage  07 , which is movable in the x-direction of a right-angled spatial coordinate system. The carriage  07  supports an approximately box-shaped housing  08 , which has an opening  09  on its side facing the paper guide roller  04 , all as seen in FIG.  1 . 
     Cleaning elements, for example two brush holders  11 ,  12 , are placed next to each other, and are displaceable back and forth in the radial direction Z of the paper guide roller  04 , as seen in FIG.  2 . These brush holders  11 ,  12 , which can be fixed in place against the wall of the housing  08 , are arranged inside the housing  08 . Each one of the brush holders  11 ,  12  takes respectively two brushes  13 ,  14 , or  16 ,  17 , which are arranged above each other. Each brush  13 ,  14 ,  16 ,  17  is respectively rotatably seated on a hollow shaft  18  arranged on the brush holder  11 ,  12 . Two brushes  13 ,  14 , or  16 ,  17 , located above each other, are driven by a motor  19 ,  21  flanged on the brush holder  11 ,  12 , for example an electric motor, via a gear  22 ,  23 . 
     Each brush  13 ,  14 ,  16 ,  17  has a rotatable brush head  24  extending in the direction toward the paper guide roller  04 . The brush head  24  is embodied as a front brush with a circle- or ring-shaped bristle trim. It is also possible to employ small plastic sponges in place of bristles. An axis of rotation  20  of each brush  13 ,  14 ,  16 ,  17  extends axis-parallel with the x-axis of the previously mentioned spatial coordinate system. On its end close to the roller  04 , each hollow shaft  18  has a spray nozzle  26 . A nozzle opening is arranged centered in each brush head  24 . 
     The brush heads  24  always turn in opposite directions of rotation. This is achieved because the motors  19 , or  21 , which work together with the pairs of brushes  13 ,  14 , or  16 ,  17 , rotate by turning toward each other. 
     Only the portions of each brush head  24 , which are in the immediate vicinity of an axis  27  extending in the z-direction, as seen in FIG. 2, are in contact with the surface  28  of the paper guide roller  04 . The portions of each brush head  24 , which are further removed from the horizontal axis  27 , are not in contact with the surface  28  of the paper guide roller  04 . 
     An axis of rotation  20  of the cleaning elements or brushes  13 ,  14 ,  16 ,  17  forms an opening angle of −45° to +45° with a radial line extending through the contact zone between the cleaning elements  13 ,  14 ,  16 ,  17  and the roller  04 . 
     The respective hollow shaft  18  of each brush  13 ,  14 ,  16 ,  17  is connected by a pressure line  29  with a pump unit  31 , whose motor  32 , which may be, for example an electric motor, is connected by electrical lines  33  with an electrical receptacle  34  fastened on the housing  08 . The pump unit  31 , in turn, is connected via a suction line  36  with a reservoir  37  for fluids, for example a cleaning fluid or a liquid separating agent. 
     The reservoir  37  has a filling connection  38  for fluids in the vicinity of the housing  08 , as well as an associated check valve  39  and an overflow line  41 . 
     On its lower side, the housing  08  is embodied as a catch basin  42  for fluids and dirt particles. Catch basin  42  is connected, via a suction line  43 , with a disposal connector  45  in the vicinity of the housing, as well as with an associated check valve  44 . 
     The motors  19 ,  21  are each connected with the receptacle  34  by electrical lines  68 ,  69 . 
     A carriage drive belt  49  is arranged within the carriage guide  06 , as seen in FIGS.,  2  and  3  via a belt drive pulley  46 , which pulley  46  is driven by a motor  47 , for example an electric motor. Carriage drive belt  49  is further supported by, for example, three further belt reversing pulleys  48 , and is guided between the lateral frames  02 ,  03 . Each of the carriage drive belt pulleys  46 ,  48  is rotatably seated on a journal  51  fixed in place on the carriage. The carriage drive belt  49  is releasable connected with the carriage  07  by means of a coupling  52 , for example a bolt with a clamping device. The carriage drive belt drive pulley motor  47  is connected via an electrical line  50  with the central electrical line  88 , as shown in FIG.  3 . 
     The carriage  07  has a contact piece  65 , for example, a bolt as shown in FIG. 2, which is fixed on the carriage, and which, during the back- and-forth movement of the carriage  07  into a left or a right end position A or B shown in FIG. 3, is in contact with an end position sensor  53  or  54  fixed on the carriage guide  06 , as seen in FIGS. 2 and 3. The end position sensors  53 ,  54  are each connected, via electrical lines  86 ,  87 , with the central electrical line  88  to the press control console. The same applies for the electrical receptacle  34 . The motor  47  of the carriage drive belt drive pulley mechanism can be switched off by the end position sensors  53  or  54 . 
     If a paper guide roller  04  is without its own drive mechanism, or without external drive, as provided by a paper web, the carriage  07  can be provided with an auxiliary paper guide roller drive mechanism, generally at  56 . 
     This auxiliary paper guide roller drive mechanism  56  consists of a two-armed lever  58 , for example, which is pivotably arranged, at a first end, on a shaft  57  seated fixed in place on the carriage, and which lever  58  supports, on its second end close to the paper guide roller  04 , a rotatably seated shaft  59  with a drive pulley  61 , for example coated with rubber, and a belt pulley  62 , arranged fixed against relative rotation in respect to the shaft  59 , of a belt drive  63 . A drive pulley  64  of the belt drive  63  is connected, fixed against relative rotation, with the support shaft  57 , which drive pulley  64  is driven by a motor  66 , for example an electric motor, all as may be seen in FIG.  1 . 
     The second end of the lever  58  can be pivoted about shaft  57  and against the force of a spring, not specifically represented, by switching on a lift magnet  67 , so that the drive pulley  61  is placed against the paper guide roller  04 . 
     The motor  66 , as well as the lift magnet  67 , are each connected with the receptacle  34  by common electrical lines  71 , so that when the motor  66  is switched on, the lever  58  with the drive pulley  61  located on it is also simultaneously pivoted away. With the appropriate activation of the motor  66 , as well as the lift magnet  67 , by means of an electrical signal issued at the start of the draw-in process, this auxiliary drive  56  can also be used to accelerate a non-driven paper guide roller  04  to the required circumferential speed prior to the draw-in of the paper web. It is a prerequisite for this that the carriage  07  is located between the end positions A, B. 
     The acceleration of the paper guide roller  04  by means of the paper web to be drawn in, and therefore the premature soiling of the paper guide roller, is avoided by this. 
     The carriage  07  furthermore has one or two doctor blade devices  72 ,  73 , as shown in FIGS. 1 and 2. Each one of the doctor blade devices  72 ,  73  is arranged at the left, or right, end of the x-axis of the carriage  07  in an area close to the paper guide roller. Each one of the doctor blade devices  72 ,  73  consists of one or more doctor blades, for example three round, or preferably polygonal, for example octagonal, doctor blades  74 ,  75 ,  76  each made of a thin material, for example of an abrasion-resistant plastic material, for example polyamide, approximately 1 mm thick, or of brass. By use of a holding device  78 , fixed in place on the carriage, the doctor blade disks  74  to  76  are arranged overlapping each other and rotatable around a center axis in such a way, that one of their eight work edges  79  always rests on an imaginary straight operating line  81 . 
     The straight operating line  81  extends at an acute angle α of, for example 3° to 8°, in respect to an imaginary line  84 , extending on the surface  28  of the paper guide roller  04  parallel with the axis of rotation of roller  04 , as seen in FIG. 1, so that the distance of the work edges  79  of the doctor blade disks  74  to  76  from the line  84  respectively increases in the direction toward the left and right lateral edges or sides  82 ,  83  of the carriage  07 . The result of this is that during a cleaning move of the carriage  07  from the right end position B in to the left end position A, the respectively wedge—like acting doctor blade disks  74  to  76  mechanically reduce the deposits of ink and paper fibers, which for example have been irregularly built up, to a minimum thickness . An overstress of the work edges  79  is avoided by the wedge-shaped or angled arrangement of the doctor blade disks. In this case, a minimal distance of approximately 0.02 mm remains between the surface  28  of the paper guide roller  04  and the doctor blade disk  76  located closest to it. 
     If the two spaced doctor blade devices  72 ,  73  are arranged as seen in FIG. 1, the work edges  79  of the two doctor blade devices  72 ,  73  form an opening angle of 164° to 174°, for example. 
     The filling connection  38  for the fluid reservoir  37 , as well as the disposal connector  45  for the catch basin  42  of the carriage  07  are each respectively connected by intermediate lines  89 ,  91  with a central supply line  92 , or with a central disposal line  93 . This can take place, for example, in that the intermediate lines  89 ,  91  between the carriage  07  and the supply line  92 , or the disposal line  93 , are designed as trailing lines. It is furthermore also possible to fill, or empty, the fluid reservoir  37  and the catch basin  42  of the carriage  07  via the intermediate lines  89 ,  91  while the carriage  07  is parked in the right end position B shown in FIG.  3 . 
     Viewed in the carriage  07  operating direction, i.e. in the axial direction of the roller  04 , the respective doctor blade device  72 ,  73  is arranged ahead of or before, in the direction of carriage travel, the brushes  13 ,  14 ,  16 ,  17 . In this way, two differently operating cleaning elements  13 ,  14 ;  16 ,  17 ;  72 ,  73  act on the roller  04 , and preferably act simultaneously, i.e. the doctor blade device  72 ,  73  is used for pre-cleaning. 
     The cleaning device of the present invention can be operated as follows: a sensor  94 , which is connected via an electrical line  95  with the central electrical line  88 , determines whether a paper web  96 , as shown in FIGS. 2 and 3 has been provided for driving the paper guide roller  04  to be cleaned, or for driving another similar roller to be cleaned, for example a draw-in roller. It is, of course, also possible for a paper web  97 , as shown in dashed lines in FIG. 2, to be wrapped around a paper guide roller  04  by 180°. If no paper web  96 ,  97  is provided, the lift magnet  67 , together with the motor  66 , is switched on by operation of the sensor  94 , so that the drive pulley  61  turns. The motor  47  is acted upon at the same time, so the carriage  07  moves out of the end position B in the direction toward the end position A. 
     Depending on a preselected mode of operation of the cleaning device  01  the surface  28  of the paper guide roller  04  can either be wiped off, or can be both wiped off and sprayed with cleaning fluid or, for intense treatment, can later be processed by the rotating brushes  13 ,  14 ,  16 ,  17 . In the last case, i.e. with intense brush cleaning, it is logical to retract the brush holder  11 ,  12  in the z-direction after reaching the end position A. It is prevented by this retraction that the fluid film applied to the surface  28  of the paper guide roller  04  is subsequently destroyed. 
     The movement, for example the retraction of the brush holders  11 ,  12  in the z axis direction, as seen in FIG. 2, can take place by use of a known, remotely controllable actuator, not specifically represented, for example a servo motor fixed in place on the carriage, and provided with a threaded spindle seated fixed in place on the carriage. 
     It is recommended to clean the paper guide or draw-in rollers at the end of a production run and to apply a liquid separating agent, for example a mixture of silicon and water, to them prior to the next start of production. 
     The reservoir  37  can be selectively filled, using the filling connection  38 , with cleaning fluid or with liquid separating agent. The amount of fluid taken up by the reservoir  37  is sufficient for spraying a roller surface. 
     During filling of the reservoir, an excess of cleaning fluid, for example 20% more cleaning fluid, is supplied to the reservoir  37 , which excess cleaning fluid then leaves the reservoir  37  through the overflow line  41  and is thus used for rinsing the catch basin  42 . 
     While a preferred embodiment of a device for cleaning a roller in accordance with the present invention has been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that a number of changes in, for example, the particular type of printing press, the overall size of the device, and the like could be made without departing from the true spirit and scope of the subject invention which is accordingly to be limited only be the following claims.