Print head arrangement and method of depositing a substance

#1. Field of the Invention

#The invention relates generally to the deposition of a substance onto a substrate using printing techniques and the like. The invention further relates to improved equipment and procedures for performing such deposition in a continuous process and has particular application in the fields of textile printing and finishing.

#2. Description of the Related Art

#The features and advantages of the invention will be appreciated upon reference to the following drawings, in which:

#FIG. 1 is a schematic view of a conventional traverse printing arrangement;

#FIG. 2 is a schematic view of a conventional fixed array printing arrangement;

#The following is a description of certain embodiments of the invention, given by way of example only and with reference to the drawings.

#Referring to FIG. 1, a conventional traverse print head system 1 is shown for printing onto a substrate 2 using inkjet techniques. The substrate 2 is transported in a direction X past a beam 4 on which is mounted a traversing inkjet print head 6 comprising a multitude of nozzles. In operation, the print head 6 traverses the substrate 2 in direction Y and prints a first strike 8A across the substrate having a width corresponding to the length of the print head 6. Although shown as a uniform layer, strike 8A is actually composed of thousands of tiny droplets or pixels. The substrate 2 is then moved forward an increment corresponding to the width of the strike 8A and halted. The print head 6 then traverses back across the substrate 2 to produce a second strike 8B. Further strikes 8C, 8D are performed in the same manner. In practice, variations to this procedure are carried out in which the strikes may overlap or which use interlacing and interweaving to place the individual droplets of one strike between those of another. A disadvantage of such a system is that the movement of the substrate is intermittent and high printing speeds are difficult to achieve.

#FIG. 2 shows a conventional fixed array printing system 10 in which a substrate 2 is transported in a direction X past a beam 4 on which a fixed head 12 is mounted. Fixed head 12 spans substantially the full width of the substrate 2. In operation, as the substrate 2 is moved, printing takes place and a strike 8 is produced over the substrate width corresponding to the width of the fixed head 12. Although this system 10 allows the substrate 2 to move continuously, frequent stoppages are necessary for preventative maintenance and repair of the head 6 or individual nozzles. Furthermore, for a given print head, only one transverse print resolution may be achieved corresponding to the nozzle spacing of the head.