Patent Publication Number: US-2018043711-A1

Title: Device to guide a band-shaped recording medium between successively arranged print groups in a printing apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to German Patent Application No. 102016115014.2, filed Aug. 12, 2016, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     The present disclosure is directed to a device to guide and/or turn a band-shaped recording medium between successively arranged print groups in a printing apparatus, in particular an ink printing apparatus. 
     An example printing apparatus is described in detail in DE 102013107451 A1 or U.S. Pat. No. 5,467,179. 
     In a first print group, the front side of a paper web is thereby printed to with a printing medium (for example ink or toner), then is turned and supplied to a second print group for printing to the back side. It is typical to use a thermal fixing station to fix the printing medium onto the paper web. 
     One problem in such printing devices is error-free running without quality losses of the print image on the band-shaped recording medium due to the turning station—a cross-turner, for example—arranged between the print groups. 
     Band-shaped recording media (made of roll paper of different paper thicknesses, for example) are subject to a thermal stress with embrittlement upon fixing in the fixing station, and then may easily be damaged by the following repeated deflection. 
     Furthermore, the monitoring of the print quality and of the paper transport is important in order to promptly detect disruptions, for example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
       The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the embodiments of the present disclosure and, together with the description, further serve to explain the principles of the embodiments and to enable a person skilled in the pertinent art to make and use the embodiments. 
         FIG. 1  illustrates a printing device having two printing stations and a turning station arranged between them, with an elongated visibility region, according to an exemplary embodiment of the present disclosure. 
         FIG. 2  illustrates an example of the turning station having an elongated visibility region according to an exemplary embodiment of the present disclosure. 
     
    
    
     The exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. 
     DETAILED DESCRIPTION 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it will be apparent to those skilled in the art that the embodiments, including structures, systems, and methods, may be practiced without these specific details. The description and representation herein are the common means used by those experienced or skilled in the art to most effectively convey the substance of their work to others skilled in the art. In other instances, well-known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring embodiments of the disclosure. 
     Exemplary embodiments of the present disclosure include a device configured to guide a band-shaped recording medium between successively arranged print groups, which device is designed to be gentle to paper and insusceptible to disruption. 
     Exemplary embodiments can include a device that is configured to enable an easy monitoring of the printing process. 
     The device according to exemplary embodiments can include a turning device, such as a cross-turner, that is configured to turn band-shaped recording media between two print groups. The turning device can include a special observation region (e.g. running orthogonally) for monitoring of the printing process. The observation region can be for the printing region that extends at least across one print side. 
     The print image printed onto the front side of the paper web therefore can simply be monitored with regard to its printing parameters such as printing offset, color accuracy and information content. 
     Furthermore, the elongated visibility region additionally cools the recording medium before the new printing to the back side in the following print group. 
     Water-cooled cooling rollers arranged in the region of the turning device additionally cool the paper web having a thermally fixed print image before said paper web is supplied to the visibility region, and thus prevent a fold formation or creasing. Furthermore, the paper web is thereby brought to a defined temperature before it is printed to on the back side in the following print group. 
     In an additional advantageous embodiment of the present disclosure, an optical scanning device (a camera, for example) is provided. The optical scanning device can be associated with the turning device, and can be a component of a monitoring device configured to verify the first print image printed on the front side. 
     According to exemplary embodiments, the print image is thereby automatically detected and is subjected to a nominal/real comparison with regard to the printing parameter. A misprint can thus already be detected and, if applicable, corrected early. 
     In an exemplary embodiment, a display configured to present the nominal page—for example in the form of a PDF file—may be arranged below the visibility region to enable a current optical nominal/real comparison. 
     A printing route shown in  FIG. 1  for two-sided printing to a band-shaped recording medium  10  can include two printing systems  30  and  40  coupled via a turning unit  20  designed as a cross-turner, with individual print groups  31 ,  32 ,  33 ,  34  and  41 ,  42 ,  43 ,  44  arranged therein and operating with liquid toner, dry toner or ink to generate the individual color separations. In an exemplary embodiment, the recording medium (e.g. paper)  10  is taken off from a supply roll  11 , supplied to the printing systems  30 , and printed to on the front side and fixed in a thermal fixing station  35 . The recording medium  10  is then turned in a turning station  20 , and the back side is printed to in a printing system  40  and fixed in a thermal fixing station  45  associated with the printing system. The recording medium  10  haven been printed to on both sides is then taken up in a take-up station  12 . 
     An exemplary embodiment of the turning station  20  is illustrated in  FIG. 2 . The turning station  20  can be designed as a cross-turner in an exemplary embodiment. In an exemplary embodiment, in a paper intake channel  50 , the turning station  20  can include a first deflection device (e.g. deflector)  51  with a sloped guidance element (e.g. sloped guide roller)  52  and a graduated guidance element (e.g. graduated guide roller)  53  that deflects the paper web  10  from a supply direction with overhead printing region  71  into a visibility region  70  traveling orthogonal to this, with frontally visible printing region  71 . The paper web  10  is thereby additionally guided via paper guidance rolls  80 . Two motorized, water-cooled drive rolls  81 ,  82  upstream of the visibility region  70  serve as a cooling device in order to further cool the print image heated in the thermal fixing device  35 ,  45  before it is supplied to the visibility region  70 . Via the cooling device, the recording medium  10  is adjusted to a defined temperature before the printing to the back side via the printing station  40 . 
     In an exemplary embodiment, the orthogonally traveling visibility region  70  in turn has an observation region  72  for the printing region  71  that extends at least across a print page. It is therefore possible to observe the printing process and monitor the print quality. 
     In an exemplary embodiment, downstream of the visibility region  70  is a paper exit channel  60  having a second deflection device  61  that likewise has a sloped guidance element  62  and a graduated guidance element  64 , which second deflection device  61  deflects the recording medium  10  supplied from the visibility region  70  in an exit direction with printing region  71  situated below (i.e. the other side of the recording medium  10 ). 
     In an exemplary embodiment, to protect the visibility region  70 , the some or all of the turning station  20  can be arranged in a housing  90  with front-side viewing plate. 
     In an exemplary embodiment, it is also possible to arrange an additional visibility region (not shown here) in the paper exit channel  60  as a control region for the paper transport. 
     In an exemplary embodiment, in, for example, high-capacity printers having a high print speed (e.g. 1 m/sec or more), a control arrangement (e.g. controller)  100  ( FIG. 1 ) can be provided. The control arrangement  100  can be connected with the drive devices of the printer and the turning station  20  to enable a quality control via reading and observing of the print image printed on the front side. After invoking a read mode, the drive of the paper web  10  is slowed intermittently so that the print images may easily be read through the visibility window in a slower operating cycle (e.g. slower than during a normal printing cycle). For example, control arrangement  100  can be configured to decrease the transport velocity of the recording medium  10  to a reading velocity based on a visibility function (e.g., the invocation of the reading mode). In an exemplary embodiment, the control arrangement  100  can include processor circuitry that is configured to perform one or more operations and/or functions of the control arrangement  100 . In an exemplary embodiment, the control arrangement  100  is a controller (e.g. that can include processor circuitry). 
     In an exemplary embodiment, so that printing may continue further with the front-side printer  30 , a paper length compensation device can be advantageously provided. In an exemplary embodiment, the paper length compensation device can be, for example, a loop puller. The paper length compensation device can be configured in the region of the turning device (turning station  20 ), such as in the intake region to the visibility region. 
     Turning to  FIG. 2 , in an exemplary embodiment, a scanner  110  with associated illumination device  120  (e.g. light source, such as light bulb, LED lamp, etc.)—for example in the form of a camera that is connected with the evaluation device—may also be arranged for automatic and continuous print quality monitoring or the paper drive. In an exemplary embodiment, the arrangement of the scanner  110  is advantageously in the intake region of the turning station  20 , but is not limited thereto. In an exemplary embodiment, the scanner  110  (e.g. camera) can be configured to detect the print image and transmit the detected print image to an evaluation device that is configured to compare the detected print image with the current nominal print image called from the controller of the first printer  30 . In operation, given corresponding deviations, the evaluation device generates (and possibly presents) evaluable warning signals. In an exemplary embodiment, the scanner  110  and/or illumination  120  can include processor circuitry that is configured to perform one or more operations and/or functions of the scanner  110 /illumination  120 . 
     In an exemplary embodiment, the nominal print image may be presented (for example in the form of a PDF file) via a display  130  arranged below the visibility region, which allows the operator a direct continuous monitoring. 
     CONCLUSION 
     The aforementioned description of the specific embodiments will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, and without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance. 
     References in the specification to “one embodiment,” “an embodiment,” “an exemplary embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     The exemplary embodiments described herein are provided for illustrative purposes, and are not limiting. Other exemplary embodiments are possible, and modifications may be made to the exemplary embodiments. Therefore, the specification is not meant to limit the disclosure. Rather, the scope of the disclosure is defined only in accordance with the following claims and their equivalents. 
     Embodiments may be implemented in hardware (e.g., circuits), firmware, software, or any combination thereof. Embodiments may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, routines, instructions may be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions in fact results from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc. Further, any of the implementation variations may be carried out by a general purpose computer. 
     For the purposes of this discussion, “processor circuitry” can include one or more circuits, one or more processors, logic, or a combination thereof. For example, a circuit can include an analog circuit, a digital circuit, state machine logic, other structural electronic hardware, or a combination thereof. A processor can include a microprocessor, a digital signal processor (DSP), or other hardware processor. In one or more exemplary embodiments, the processor can include a memory, and the processor can be “hard-coded” with instructions to perform corresponding function(s) according to embodiments described herein. In these examples, the hard-coded instructions can be stored on the memory. Alternatively or additionally, the processor can access an internal and/or external memory to retrieve instructions stored in the internal and/or external memory, which when executed by the processor, perform the corresponding function(s) associated with the processor, and/or one or more functions and/or operations related to the operation of a component having the processor included therein. 
     In one or more of the exemplary embodiments described herein, the memory can be any well-known volatile and/or non-volatile memory, including, for example, read-only memory (ROM), random access memory (RAM), flash memory, a magnetic storage media, an optical disc, erasable programmable read only memory (EPROM), and programmable read only memory (PROM). The memory can be non-removable, removable, or a combination of both. 
     REFERENCE LIST 
     
         
           10  recording medium, paper web 
           11  stock roll 
           30 ,  40  printing systems 
           31 ,  32 ,  33 ,  34  individual print groups, printer  30   
           41 ,  42 ,  43 ,  44  individual print groups, printer  40   
           20  turning device 
           35 , 45  fixing station 
           12  take-up station 
           50  paper intake channel 
           51  first deflection element, deflection device 
           52  sloped guidance element 
           53  graduated guidance element 
           60  paper exit channel 
           60  second deflection element, deflection device 
           61  sloped guidance element 
           63  graduated guidance element 
           70  visibility region 
           71  printing region 
           72  observation region 
           80  paper guide rolls 
           81  water-cooled drive roll 
           82  water-cooled drive roll 
           90  housing 
           100  control arrangement 
           110  scanner, camera 
           120  illumination device 
           130  display