Patent Publication Number: US-2019176499-A1

Title: Digital printing machine

Description:
TECHNICAL FIELD 
     The present invention relates to a digital printing machine, particularly a roll to roll machine. 
     PRIOR ART 
     A digital printing machine of the roll to roll type operates on a textile, which initially is wound about a first roll, is unwound, associated with a guide belt, subjected to digital printing (e.g., ink-jet printing), dried and wound again onto a second roll. 
     Such machine comprises a base, a cross-beam and a printing carriage. 
     The base supports the cross-beam; the printing carriage moves along the cross-beam, in a direction substantially orthogonal to the advancement direction of the textile. 
     The carriage typically is connected electrically to the rest of the machine to receive both the power (movement along the cross-beam and vertical movement) and to receive the control signals intended for the printing device mounted on the carriage. 
     The Applicant has verified that problems in receiving such control signals occur with a certain frequency. In particular, the following may occur:
         one or more data packets are not received by the printing device and therefore the printing of a specific portion of textile is not performed;   one or more data packets undergo distortions or are modified by electromagnetic noise, so that the print executed is different from the one desired.       

     The Applicant has also noted that a source of disturbance capable of creating the aforesaid problems consists of the “power” connection that brings power to the carriage. Indeed, for matters of simplicity and distribution of the components, the data cables (that bring the control signals to the printing device) and the power cables (that bring the power to the various components) are kept close to one another so as to substantially follow the same path. 
     This necessarily induces interferences and disturbances which as mentioned, have a negative impact on the reception of the data by the printing device. 
     The prior art proposes the use of isolating and shielding elements as a solution, which in addition to not resolving the problem in a satisfactory manner, results in increasing the complexity and costs of the structure of the machine. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is therefore the object of the present invention to propose a digital printing machine, particularly a roll to roll machine, capable of drastically reducing the probability of error in receiving data and control signals from the printing device mounted on the printing carriage. 
     It is another object of the invention to make available a digital printing machine, particularly a roll to roll machine, that is characterized by a simple and affordable structure. 
     It is a further object of the invention to provide a digital printing machine, particularly a roll to roll machine, in which the transmission of data/signals to the printing device mounted on the printing carriage may be carried out in a quick and secure manner. 
     These and other objects again are substantially achieved by a digital printing machine, particularly a roll to roll machine, as described in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages shall be more apparent from the detailed description of a preferred, but not exclusive, embodiment of the invention. 
       Such description is made herein below with reference to the accompanying drawings, also provided for indicative only and therefore not limiting purposes, in which: 
         FIGS. 1-2  show block diagrams representative of the invention; 
         FIG. 3  shows a perspective diagrammatical view of a first part of the machine in  FIG. 1-2 ; 
         FIG. 4  shows a perspective diagrammatical view of a second part of the machine in  FIG. 1-2 ; 
         FIG. 5  shows a perspective diagrammatical view of a third part of the machine in  FIGS. 1-2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the accompanying drawings,  1  indicates a printing machine according to the invention. 
     The printing machine  1  preferably is a roll to roll machine, that is a machine in which the textile is initially wound onto a first roll, then it is unwound for printing, and finally it is rewound onto a second roll after drying. 
     The machine  1  firstly comprises a base ( 10 ). 
     The base  10  ( FIG. 3 ) comprises at least two vertical walls  11 ,  12 , and one or more transverse portions joining said vertical walls and integral therewith. 
     The base mainly serves the purpose of supporting the cross-beam  20 , which is better described below. 
     To this end, the base  10  has a resting zone  14   a - 14   b  on which the cross-beam  20  is rested and fixed. 
     The cross-beam  20  ( FIG. 4 ) has an elongated shape, for example a substantially parallelepiped shape. 
     Preferably, the cross-beam  20  has a base wall  21  suitable for being rested on the resting zone  14   a - 14   b  of the base  10 . 
     Preferably, the cross-beam  20  also has a front wall  22  having a guide for a printing carriage  30 . 
     The printing carriage  30  comprises a frame  31  and a printing device  32 , supported by said frame  31 . 
     The frame  31  ( FIG. 5 ) is mounted on the cross-beam  20  so as to be moved along it by substantially straight alternating motion. In other words, two respective stroke end positions are defined at the ends of the cross-beam  20 , and by supporting the printing device  32 , the frame  31  is continuously moved between the two stroke end positions. 
     The printing device  32  may be for example, an ink-jet printing device. 
     There are also provided first moving means  40  adapted to move the printing carriage  30  along the cross-beam  20  ( FIGS. 4-5 ). 
     Such first moving means  40  may comprise for example, an electromechanical actuator or a pneumatic actuator; alternatively, any actuator capable of obtaining the above-described movement may be used. 
     The machine  1  further comprises second moving means  50  adapted to move the printing device  32  in a vertical direction, substantially orthogonal to the lengthwise extension of the cross-beam  20 . 
     The second moving means  50  may comprise for example, an electromechanical actuator or a pneumatic actuator; alternatively, any actuator capable of obtaining the above-described movement may be used. 
     Preferably, the second moving means  50  are mounted on the frame  31  so as to conveniently act on the printing device  32 . 
     The machine  1  further comprises a control unit  100  associated with the printing device  32 . 
     The control unit  100  substantially is integral with the fixed parts of the machine  1 , such as for example the base  10  and the cross-beam  20 . 
     The control unit  100  serves the purpose of receiving the input printing data, for example in the form of digital image, and of sending corresponding control signals to the printing device  32  so that the latter may replicate the decorations provided on the textile. The configuration and setup data required for a suitable operation of the machine  1  are also entered in the control unit  100 . 
     The control unit  100  is also configured to receive power from the power network and to distribute it to different parts of the machine  1  in a suitable manner. In particular, the power may be supplied to the printing device  32 , the first moving means  40 , the second moving means  50 , etc. 
     According to the invention, the control unit  100  is connected with the printing carriage  30  by means of an electrical connection EC obtained with an electric cable that is in itself known. 
     Due to this connection, the electrical parts of the printing carriage  30  (printing device  32 , first moving means  40 , second moving means  50 , etc.) may be powered. 
     The control unit  100  is also connected to the printing device  32  by means of an optical connection OC, made for example like an optical fibre. 
     The control unit  100  may send the printing device  32  data and/or control signals by means of such optical connection OC so that the printing activity provided is executed. 
     In greater detail, the control unit  100  is configured in a native manner to generate control signals in electronic format. The latter are converted into optical format by means of a first electro-optical converter EO. 
     The signals and/or data thus converted are transmitted to the printing device  32  by means of the optical connection OC. 
     The printing device  32  is configured in a native manner to receive control signals and data in electronic format; therefore it is provided for a second electro-optical converter OE, interposed between the optical connection OC and the printing device  32  itself, to convert the control signals into an electronic format and/or the received data into an optical format. 
     In light of the above, the advantages obtained by the invention are apparent. 
     Firstly, the probability of error in receiving data and control signals from the printing device mounted on the printing carriage is drastically reduced. 
     The overall structure of the machine is also made simpler and more affordable because there is no need to prepare specific isolations and shields between the power connection and the data connection. 
     The rapidity and security of the data transmission from the control unit to the printing device are also improved.