Abstract:
A process and an apparatus for the production of labeled plastic bottles, to produce labeled bottles at a high output rate and with a reliable label hold wherein the bottles are labeled in a continuous flow directly after leaving the blowing machine. The bottles are still clean and dry, and allow for a reliable attachment of the labels at a high rate.

Description:
FIELD OF THE INVENTION 
     The invention pertains to a process and an apparatus for the production of labeled plastic bottles. 
     BACKGROUND OF THE INVENTION 
     In the production of labeled plastic bottles it is known (DE-AS 17 04 022), to first continuously produce plastic bottles from blanks in a blowing machine. Blowing machines of this kind take the preheated blanks, also called preforms, into specially designed blow molds, in which they are blown into bottles at high pressure and high temperature during the rotation of the blowing machine. At the outlet of the blowing machine the bottles are then passed on to an output star wheel. 
     In this method known in the art, the bottles, once ready, are passed on from the output star wheel to a filling machine, which operates in a rotary manner as well. There the bottles are filled with the desired liquid. Then the bottles are capped by a bottle capping machine and passed on to a labeling machine. The disadvantage of this system is that it is not always possible to ensure that the outside surface of the bottle, which will be labeled, stays dry and clean during the filling and capping procedure, which is an essential precondition for reliable labeling. 
     It has also been proposed (DE-OS 26 21 993) to pass on the bottles from a blowing machine to a carousel in a clocked manner, and to perform different treatment steps intermittently in this carousel, that is to say first a testing procedure, then the labeling, then the printing, then the filling and then finally the capping and the packaging. The disadvantage here is that this clocked operation does not allow for high output rates. 
     SUMMARY OF THE INVENTION 
     It is the task of the invention to provide a process and an apparatus, by means of which labeled plastic bottles can be produced at high capacity and with a nonetheless reliable label hold. 
     In the process according to the invention, the plastic preforms, after having been continuously created in a blowing machine, preferably in a rotary blowing machine, are then continuously labeled without the interposition of any further treatment steps and directly afterwards, i.e. downstream from the blowing machine, whereby only the pitch distance has to be adjusted to the distance required for labeling, if necessary. The advantage of this is that by means of the immediately consecutive arrangement of the blowing and labeling procedure it can be ensured that the bottles, leaving the blowing machine absolutely dry and clean, are labeled directly afterwards, so that the label can be attached reliably on a clean surface. The continuous operation, as opposed to a clocked operation, allows for substantially greater bottle output per hour, and consequently for a greater capacity of the system. 
     In an advantageous embodiment of the process, the bottles, after leaving the blowing machine, are passed on to an output star wheel, where they are set at the pitch distance required for labeling. Preferably, to implement this step, an output star wheel is used which has controllable gripper arms for the bottles which allow for modifying the distance between the consecutive bottles. Such transporter stars are known in the art (for example DE-OS 3837 118, to which express reference is made here). Despite continuous operation, such proceeding saves a lot of space and provides for an efficient blocking of the blowing and labeling machine, since the output star wheel can at the same time be used as the input star wheel for the downstream labeling machine. 
     An output star wheel without pitch distance control, however, can also be used. In this case, a downstream distancing worm screw can be used, if necessary. 
     More than ever, the advantages of the invention become noticeable when a label preformed as a sleeve has to be pulled over the bottles in the labeling machine. A heat shrinking tubular foil or a stretch foil is usually used for these so-called sleeve labels, from which foil sleeve shaped sections are prepared. The sleeve diameter is selected to be only slightly wider then the diameter of the bottle in the area, where the label will be attached. If the bottle is clean and dry, there are no problems with adhesion of the foil in moist spots or similar during the pulling process, rather, the sleeve label can be attached very easily and troublefree. Afterwards the label is fixed to the bottle by exposure to heat or mechanical shrinking due to earlier stretching. 
     It is also possible to utilize the invention in conjunction with a labeling unit which attaches labels to bottles in a traditional way, for example by gluing the whole surface or part of it. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention shall be explained further by means of the figures below. The figures show: 
     FIG. 1 is the top view of a first exemplified embodiment of an apparatus according to the invention; and 
     FIG. 2 is the top view of a second exemplified embodiment according to the invention in a schematic view. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1, the apparatus according to the invention for the production of labeled plastic bottles  15  is indicated collectively as  1 . The apparatus  1  includes a blowing machine for the production of plastic bottles  15 , which is constructed in the form of a carousel and rotates around the vertical axis A. The blowing machine includes a heating wheel  2  at the top (shown only partially), to which the blanks or preforms  5  are brought in by means of an input star wheel  6 . By means of a transfer device not specified here in more detail, the preforms, preheated to the required blowing temperature in the heating wheel  2 , are then passed on to the blowing wheel  3  arranged below, in which the appropriate molds for the production of plastic bottles are arranged by means of opening and closing clamps  4 . During a continuous rotation of the blowing wheel  3  in the direction U, plastic bottles  15  are produced from preforms  5 . A blowing machine of this kind with the heating wheel at the top and the blowing wheel arranged concentrically below is known from DE-GM 297 20 311. 
     After the clamps  4  open, the plastic bottles  15  produced in the blowing wheel  3  are taken over by an output star wheel  7  continuously rotating in the direction of the arrow. The output star wheel  7  has controllable gripper arms  8 , which are, in addition, able to pivot in the direction of the rotation, i.e. are able to create an additional velocity component in the direction of the rotation, and are further arranged in a radially movable manner, so that the bottle position can be modified in the radial direction as well. By means of such output star wheel  7 , the bottles  15  taken from the blowing wheel  3  can be set at the pitch distance required for the labeling machine  16  arranged downstream. 
     The labeling machine  16 , as arranged downstream to the output star wheel  7 , includes a rotary table  9 , on which rotary rolls  10  are arranged in pairs, to which the bottles  15  are passed on. In the area of the rotary table  9 , a labeling unit  10  is arranged, which attaches sleeves  18  (label sleeves made of heat shrinking plastic foil) to the bottles  15  in a manner known in the art. A labeling machine of this kind is specified in WO-OS 95/27613, to which express reference is made here. The bottles  15 , labeled directly downstream from the blowing machine, are passed on by means of an output star wheel  13  into a transport route, for example a suspended conveyor, as it is indicated by  12  in FIG.  1 . From there, they are passed on, for example, to a filling machine. 
     In this exemplified embodiment, as has been specified, the output star wheel of the blowing machine has gripper arms  8  controllable in such a manner that it is able to set the bottles  15  at the pitch distance required for the labeling machine  16  arranged downstream. The output star wheel  7  is thus at the same time used as the input star wheel for the labeling machine  16 . This compact construction allows, in a very advantageous manner, for the bottles  15 , produced in the blowing wheel  3 , to be clean and dry at the labeling procedure occurring in a continuous flow and directly downstream, which facilitates the labeling procedure in the labeling unit and provides for a troublefree labeling. The compact construction reduces the instrumentational expenditure and allows for the labeling to occur in a continuous flow, which eliminates the need for an intermediate storage of the bottles behind the blowing wheel. The continuous mode of operation allows for a high output. 
     The same advantages are also achieved by means of the machine shown in FIG. 2, in which parts with the same function are indicated with the same reference numbers as in FIG.  1 . The blowing machine has the same construction as in FIG.  1 . Only the blowing wheel  3  arranged at the bottom is shown. The difference between this exemplified embodiment of FIG.  2  and the one shown in FIG. 1 is that here the output star wheel  7 , to which the bottles are passed on after leaving the blowing wheel  3 , operates without controllable gripper arms, thus having a simpler construction, but passing the bottles on to two distancing worm screws  14   a,    14   b,  which then set the bottles  15  at the pitch distance required for the labeling machine  17  arranged downstream. The labeling machine comprises two labeling units  11   a,    11   b,  one of which is, for example, used to attach the body label and the other the neck label. The construction and mode of operation of such machine is known in the art and does not require further explanation. In this solution, a traditional labeling machine is blocked directly to the blowing machine, and the pitch distance of the bottles is set by means of at least one distancing worm screw. Here, too, the bottles are still clean and dry when they are being labeled, which facilitates the labeling. Here, too, the operation is continuous, which allows for a high output.