Abstract:
A device for use in a rotary printing machine having at least one printing mechanism including a plate cylinder which can be releasably mounted on a shaft carrying the plate cylinder. The plate cylinder and the shaft can be oriented both axially and also in the peripheral direction relative to the shaft and thus relative to the article to be printed. When the plate cylinder and the shaft are oriented as desired, the plate cylinder is capable of being fixedly attached to the shaft. The plate cylinder can be fixed in the peripheral direction and in the axial direction.

Description:
FIELD OF THE INVENTION 
     The invention concerns a device for use in a rotary printing machine. 
     BACKGROUND OF THE INVENTION 
     A typical form of rotary printing machine has at least one printing mechanism including a plate cylinder which can be releasably mounted to a shaft carrying it. The plate cylinder carries a printing plate which is fixedly connected thereto. If the printing plate is provided with the respective print image to be produced, in a special imaging or image-applying apparatus, that is to say outside the printing mechanism itself, it is then necessary for the printing or blanket cylinder, upon being fitted into the printing mechanism, to be properly oriented with respect to the shaft which carries it, in such a way that the print image which is transferred from the printing plate on to the printing cylinder is correctly oriented with respect to the article to which the printing is to be applied and on to which therefore the printing or blanket cylinder transfers the print image. In view of the fact that in many cases the number of articles to which printing is to be applied in the same fashion, that is to say the number of articles constituting a respective batch, may be very low, there is a need for the printing plate to be changed at short intervals of time. If the printing plate is fixedly connected to the plate cylinder, frequent changes in the printing plate entail correspondingly frequent changes in the plate cylinder. The amount of time that this involves is particularly significant when, as is normally always the case in offset printing, the article is to be successively provided with a plurality of partial print images each consisting of different colors or inks, which supplement each other to form an overall print image. This therefore requires a corresponding number of printing mechanisms and accordingly also plate cylinders, in the rotary printing machine. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a rotary printing machine which permits plate cylinder changes to be implemented in a simple fashion involving a minimum amount of time. 
     Another object of the present invention is to provide a rotary printing machine affording a structure such as to permit accurate adjustment of the respective plate cylinder so as to satisfy the nowadays usual demands in terms of print image quality. 
     Still a further object of the present invention is to provide a rotary printing machine affording adjustability of plate cylinder and print image such as to satisfy the particularly high demands in terms of accuracy of adjustment which are involved when an article to be provided with printing thereon is to be successively provided with a plurality of partial print images which must be accurately positioned relative to each other. 
     In accordance with the principals of the present invention the foregoing and other objects are obtained by a rotary printing machine having at least one printing mechanism which includes a plate cylinder which can be releasably mounted on a shaft carrying it. The plate cylinder and the shaft are adapted to as to enable orientation of the plate cylinder relative to its shaft both axially and also in a peripheral direction, and for fixing the plate cylinder to a shaft in an oriented position with respect thereto. The plate cylinder includes a means of positioning which comprises a first and second projection. Associated with the shaft is an adjustment means for adjusting the position of the positioning means enabling the plate cylinder to be positioned as desired. The adjustment means comprises a first and second adjustable bolt. The first projection is co-operable with the first adjustable bolt which is operatively associated with the shaft for fixing the position of the plate cylinder in the peripheral direction. The second projection is co-operable with the second adjustable bolt which is operatively associated with the shaft to fix the axial position of the plate cylinder relative to the shaft. The first and second adjustable bolts include a region against which the respective positioning means come to bear so as to enable convenient and accurate positioning of the plate cylinder in either the peripheral direction or the axial direction. 
     In accordance with a preferred feature of the invention, operatively associated with the plate cylinder is a collar which is also arranged on the drive shaft thereof and which is provided with the adjustable bolts, while the-first and second projections located on the plate cylinder are introduced into openings in the collar that are brought into contact in the openings with the adjustable bolts which determine the position of the plate cylinder both axially and also in the peripheral direction. 
     In accordance with a further preferred feature of the invention the use of conically tapering portions of said bolts which are adjustable in the direction of the longitudinal axis thereof affords the advantage that the operating position of the plate cylinder can be very accurately adjusted relative to the shaft by simple axial displacement of the conically tapering portion. 
     An operating procedure which has been found to be particularly advantageous is one in which the imaging apparatus is also so designed that the positioning of the plate cylinder in the imaging apparatus is in conformity with the positioning thereof in the printing mechanism so that it is only necessary for the imaged plate cylinder to be removed from the imaging apparatus and fitted on to the drive shaft in the printing mechanism, whereupon, using the arrangement according to the invention, orientation thereof can be effected therein, relative to the shaft, without each change in plate cylinder necessitating displacement of the conically tapering portions for the purposes of adjusting the position of the plate cylinder in the axial direction and in the peripheral direction. On the other hand however the invention also permits fast and in particular accurate adjustment of the plate cylinder in a simple fashion in the situations in which the conically tapering portions for determining the position of the plate cylinder on the shaft have to be set for the first time or re-adjusted so that a fast change of the plate cylinders including accurate adjustment thereof is possible even when the position of the plate cylinder in the imaging apparatus is not defined in relation to the position of the plate cylinder in the printing mechanism. 
     It will be appreciated that it is assumed in all cases that the position of the plate which is respectively carried by the plate cylinder is accurately fixed and defined in relation to the plate cylinder. 
     Further objects, features and advantages of the invention will be apparent from the following description of a preferred embodiment of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a side view of a plate cylinder, 
     FIG. 2 shows a front view of the FIG. 1 structure, 
     FIG. 3 is a side view of a unit comprising a drive shaft, a plate cylinder and associated components, 
     FIG. 4 shows a view in section taken along line IV—IV in FIG. 3, 
     FIG. 5 shows a view in section taken along line V—V in FIG. 3, 
     FIG. 6 shows a view in section taken along line VI—VI in FIG. 3, 
     FIG. 7 shows a detail from FIG. 2 on an enlarged scale, 
     FIG. 8 shows a plan view of the detail in FIG. 7, and 
     FIG. 9 is a view in longitudinal section of the detail of FIG.  7 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring firstly to FIGS. 1 through 3, reference numeral  10  denotes a mounting shaft of a printing mechanism of which at least one is contained in a rotary printing machine. The at least one printing mechanism further includes a plate cylinder which is generally indicated at  12  and which is mounted releasably and thus interchangeably on the shaft  10  which carries it. Connected upstream of the plate cylinder  12  in the printing mechanism is an ink roller (not shown). The plate cylinder  12  carries a printing plate (not shown) which has been provided with the appropriate print image to be applied to an article. The ink which is applied to the printing plate by the inking roller is transferred in accordance with the print image on to the printing blanket of the printing or blanket cylinder (not shown) which also forms part of the printing mechanism, and from the blanket on to the article to which the printing is to be applied. It will be appreciated that the arrangements and operating procedures just outlined above are readily familiar to the man skilled in the art for example in connection with offset printing machines so that details thereof do not need to be particularly described herein. 
     The printing plate which in operation of the printing mechanism is carried on the plate cylinder  12  is provided with the appropriate print image in a separate special image-applying or imaging station, for example by means of a laser. Thereupon the plate cylinder  12  is fitted on to the shaft  10  and secured thereto. As it is necessary for the print image and therewith the printing plate to be oriented in a specifically defined manner with respect to the article to which printing is to be applied, the plate cylinder  12  has to be suitably oriented with respect to the drive and mounting shaft  10  on which it is driven in rotation. 
     For that purpose, the plate cylinder  12  is provided with a means of positioning adapted to work together with an adjustment means so as to enable the convenient and accurate positioning of the plate cylinder. In a preferred embodiment, the means of positioning includes a first projection  16  and a second projection  18 . The first projection  16  serves to fix the position of the plate cylinder with respect to the shaft in the peripheral direction of the shaft  10  and the plate cylinder  12 . The first projection  16  illustrated in this embodiment is in the form of a cylindrical pin which is inserted in a bore  17  at the one end of the plate cylinder  12  and forms a projection which protrudes with respect to the end face  14  of the plate cylinder  12 . It should be understood however that the pin may be formed in any shape. 
     The second projection  18  serves for fixing the position of the plate cylinder  12  relative to the shaft  10  in the direction of the longitudinal axis of the shaft  10  or the plate cylinder  12 . The second projection  18 , in a preferred embodiment, is in the form of a T-shaped member indicated at  22  and shown in somewhat greater detail in FIGS. 7 through 9. It will be seen from FIG. 1 however that the second projection  18  projects with respect to the end face  14  of the plate cylinder  12 . The second projection  18  is fixed to the plate cylinder  12  by means of two screws shown in FIG.  1  and indicated at  20  in FIGS. 2 and 3, which engage into corresponding screwthreaded bores at the end face  14  of the plate cylinder  12 . The two screws  20  extend through holes  26  provided on the head flange portion  24  of the second projection  18 . 
     Reference numeral  30  in FIG. 3 denotes a collar which is disposed on the shaft  10  at a position beside the plate cylinder  12  which is also carried on the shaft  10 , at a small spacing from the end face  14  at which the first and second projections  16  and  18  are disposed. The collar  30  is fixed to the shaft  10  by way of a radial pin indicated at  32  in FIG. 3 which for fixing purposes is cast using a suitable plastic material in a bore  34  in the collar  30 . The collar  30  is of an annular configuration in cross-section and is provided with two flats which form flat surface portions  36 ,  37  extending in mutually right-angled relationship, as can be clearly seen from FIG.  4 . 
     In the region in which the collar  30  is disposed, the shaft  10  is provided with two substantially radial bores  38  and  40  which can be clearly seen from FIGS. 4 and 5. The bores  38 ,  40  are displaced relative to each other in the direction of the axial extent of the shaft  10  and extend substantially in right-angled relationship with each other. As can be seen from FIG. 4, the first bore  38  is continued at each end into a coaxial bore portion  42  and  43  respectively in the collar  30 , in such a way that the bore  38  in the shaft  20  and the bore portions  42 ,  43  in the collar  30  supplement each other to form a continuous means for receiving a first adjusting bolt  48 . In a corresponding manner, the second bore  40 , at each end, is continued into a bore portion  44  and  45  respectively in the collar  30 , in such a way that the second bore  40  and the bore portions  44 ,  45  are adapted to receive a second adjusting bolt  50 . 
     As the two adjusting bolts  48  and  50  are of the same configuration and involve the same mode of operation, only the first adjusting bolt  48  will be described hereinafter. 
     Referring therefore now to FIG. 4, at its end which is towards the flat surface  36  in FIG. 4, the first adjusting bolt  48  has a portion  52  which projects with respect to the surface  36  of the collar  30  and which is provided with a first fixedly mounted adjusting knob  56 , by means of which the adjusting bolt  48  can be turned about its longitudinal axis. Adjoining the smaller-diameter bolt portion  52  is a portion indicated at  53  in FIGS. 4 and 5 and which is provided on its outside with a screwthread engaging with a female screwthread indicated at  55  in Figure, which is provided in the bore portion  43  and in the portion of the bore  38 , that is towards the adjusting knob  56 . Adjoining the screwthreaded portion  53  is a bolt portion  57  without a screwthread, which is guided to achieve an accurate fit in a sleeve or bush indicated at  59  in FIG.  4 . The sleeve or bush  59  is fitted in the region, remote from the adjusting knob  56 , of the bore  38  which is within the shaft  10 . Adjoining the bolt portion  57  is a conically tapering portion  60  which tapers towards the adjusting knob  56  and serves as an abutment. The conical portion  60  continues at its larger-diameter end into a shorter cylindrical bolt portion  61  which is mounted with a close fit, with the interposition of a sleeve or bush  63 , in the bore portion  42  in the collar  30 . 
     By virtue of the operative engagement between the male screwthread on the bolt portion  53  and the female screwthread portion  55  in the bore  38  in the shaft  10 , rotation of the adjusting bolt  48  about its longitudinal axis, which is effected by turning the adjusting knob  56 , at the same time results in axial displacement thereof with its conical portion  60 , in one direction or the other. 
     Looking now at FIG.  3  and FIG.  4 . the collar  30  is provided with a first recess or opening  54  which starts from the end face of the collar that faces towards the plate cylinder  12 . This arrangement of the opening  54  can be particularly clearly seen in FIG.  3 . The opening  54  is arranged in such a way that the conical portion  60  of the bolt  48  is disposed within the opening  54  into which, in the assembled condition of the components, the first projection  16  projects to determine the position of the plate cylinder in the peripheral direction relative to the shaft, as can be seen in particular from FIGS. 1 and 4. In this respect, the position at which the first projection  16  bears against the conical portion  60  of the bolt  48  (see FIG. 4) determines the position of the plate cylinder  12  in the peripheral direction. By virtue of the conical configuration of the bolt portion  60 , axial displacement thereof also results in a corresponding change in position of the first projection  16  and thus the plate cylinder  12  in the peripheral direction so that suitable adjustment of the first adjusting bolt  48  and therewith the conical bolt portion  60  by way of the adjusting knob  56  can determine the position of the plate cylinder  12  in the peripheral direction. 
     The collar  30  is also provided with a second recess or opening which is indicated at  58  in FIGS. 4 and 5 and which is arranged to extend continuously through the structure in such a way that the conical portion  65  of the second adjusting bolt  50  is disposed within the second opening  58 . The radial extent thereof can also be slightly greater than the radial extent of the operatively associated conically tapering bolt portion  65 . Adjustment of the second adjusting bolt  50  and therewith the conical bolt portion  65  by way of the second adjusting knob  56 A can determine the position of the plate cylinder  12  in the direction of the longitudinal axis of the shaft  10 . 
     It will be noted that the extent of each of the two openings  54  and  58  in a plane transverse with respect to the longitudinal axis of the mounting shaft  10  is noticeably larger than the largest diameter of the respective conically tapering bolt portion  60  and  65  respectively. 
     A prerequisite to achieve the desired orientation of the plate cylinder  12  with respect to the shaft  10  is that, when the plate cylinder  12  is pushed on to the shaft  10 , the two projections  16 ,  18  assume a position in the peripheral direction of the collar  30  such that they are disposed in opposite relationship to the respective openings  54  and  58  in the collar  30  and thus engage into the openings. In that respect, it is to be noted that the projection  16  is introduced into the opening  54  at the correct side of the conically tapering bolt portion  60 , for properly establishing the position of the plate cylinder in the peripheral direction. As already indicated above. the axial movement involved in pushing the plate cylinder  12  on to the shaft  10  is limited by the end boundary face  64  encountering the conically tapering portion  65  of the second adjusting bolt  50 , in which case contact between the end face  64  and the conically tapering bolt portion  65  determines the correct position of the plate cylinder  12 . Thereafter, the plate cylinder  12  is turned about the shaft  10  to such an extent with respect to the shaft  10  until the first projection  16 , which in a preferred embodiment is a pin, bears with its peripheral surface  62  against the conically tapering portion  60  of the first adjusting bolt  48 . When that contact occurs, with contact between the second projection  18  and the conical portion  65  of the second adjusting bolt  50  being maintained at the same time, that is a guarantee that the plate cylinder is in the correct position relative to its support shaft  10 . 
     The above-mentioned rotary movement of the plate cylinder  12  about its shaft  10 , which is normally required for establishing its position in the peripheral direction, also results in a corresponding movement of the projection  18  with respect to the conically tapering bolt portion  65  so that the end face  64  of the second projection  18 , which co-operates with the conically tapering bolt portion  65 , should be of a peripheral extent which is not less than the magnitude of the maximum rotary movement which the plate cylinder experiences in order to bring the first projection  16  into contact with the conically tapering bolt portion  60  associated therewith. 
     Reference will now be made to the preferred embodiment of the second projection  18  as shown in FIGS. 8 and 9. FIGS. 8 and 9 show more particularly that the second projection  18  is of such a configuration as to be curved around the axis of rotation of the shaft  10 , that is to say it extends in coaxial relationship with that axis of rotation. In that respect, as considered in longitudinal section through the second projection  18 , or more specifically the end portion  66  thereof, the end face  64  is profiled in such a way that along a center circle  68  it has a projection as indicated at  70  in FIG. 9, thereby involving substantially punctiform contact between the end face  64  and the conical bolt portion  60 . By virtue of the arcuate configuration of the projection  70  along the circle  68 , the end face of the second projection  18  is always in contact, that is to say irrespective of the position of the second projection  18  in the peripheral direction, with the same point of the conical portion  65 , and thus a movement of the second projection  18  about the axis of rotation of the shaft  10  and the plate cylinder  12  does not result in an axial change in position of the plate cylinder  12  on the shaft  10 . 
     Associated with each of the two adjusting bolts  48 ,  50  is a more or less elastically deformable plastic body as indicated at  67  in FIG. 4, which is pressed against the screwthreaded bolt portion  53  by a screw  69  in FIG. 4 in order thereby to prevent unwanted rotation of the adjusting bolt  48  or  50  respectively and in order thus to secure the adjusting bolt in its set position. On the other hand, possibly after slackening of the screw  69 , there is nonetheless the possibility of adjusting the adjusting bolt  48  or  50  respectively by manually rotating the respective adjusting knob  56  or  56 A in order to adjust the respective conical portion  60  or  65 , in accordance with the desired position for the plate cylinder  12  on its shaft  10 . The screw  69  is carried in a screwthreaded bore within the collar  30 . 
     After the above-described operation of orienting the plate cylinder  12  with respect to the shaft  10 , the plate cylinder  12  is fixed on the shaft  10  by expansion of the latter. For that purpose, at least in the region in which it carries the plate cylinder  12 , the shaft  10  is of a hollow structure and is filled with a hydraulic fluid. At the end of the shaft  10  which is remote from the two projections  16 ,  18  on the plate cylinder  12 , the shaft  10  has a closure screw which is indicated at  74  in FIG. 3 having a male screwthread engaging into a corresponding female screwthread on the shaft  10 . Actuation of the screw  74  by screwing it into or out of the hollow shaft consequently results in a reduction or an increase in the size of the internal space defined within the hollow shaft  10  and thus results in an increase in or a reduction in the pressure of the hydraulic fluid within the hollow region of the shaft  10 . After the plate cylinder  12  has been moved on to the shaft  10  in the manner described hereinbefore and oriented with respect to the shaft by the action of the two conically tapering bolt portions  60 ,  65 , the plate cylinder  12  is fixed on the shaft  10  by suitable actuation of the closure screw  74  in such a way that an increase in the pressure of the hydraulic fluid in the hollow region of the shaft causes the hollow shaft  10  to experience slight radial expansion, by means of which the plate cylinder  12  is suitably fixed on the shaft  10  in the mutually oriented positions thereof. To remove the shaft  10  it is then only necessary to rotate the closure screw  74  in such a way that there is a drop in the pressure of the hydraulic fluid within the shaft  10  and the shaft  10  thus experiences a reduction in diameter by virtue of its elastic nature and the clamping connection to the plate cylinder  12  is thus released. 
     It will be appreciated that the above-described embodiment of the invention has been set forth solely by way of example and illustration of the principles thereof and that various other modifications and alterations may be made therein without thereby departing from the spirit and scope of the invention.