In particular, the invention aims processing machines such as printer or conversion machines or whereby the feeding of the substrate before the processing and the removal of the substrate after the processing takes place on one and the same side of the processing machine, and in opposite directions .

A known example of such a machine is a printer applying an image onto a substrate, such as tiles, garments such as T- shirts or other objects, for example by means of an inkjet nozzle, for which printers are offered by several manufacturers worldwide, whereby the substrate is always being fed in and also fed out on one and the same side of the machine.

A disadvantage of such a machine is that the substrate must be manually fed on one side of the printer and must also be removed on the same side by moving the substrate in the opposite direction.

While the finished substrate leaves the printer, the next substrate to be processed cannot be fed in yet, resulting in loss of time and hence a low production capacity. Another disadvantage of such a machine is that the feeding in and out of the substrate cannot be integrated in a continuous unidirectional production line and an automated production process, whereby the substrate is automatically fed in and out in one and the same direction.

The present invention aims to remedy the above-mentioned and other disadvantages. To this end, the invention concerns an optional module for an existing processing machine, such as a printer or conversion machine, whereby the existing processing machine is of the type which is equipped with a feed-in and feed- out system for a substrate on one and the same side of the machine, whereby the optional module is such that the existing processing machine is transformed into a continuous production unit whereby the substrate is fed in and fed out on opposite sides. An advantage is that the optional module makes it possible to reduce the processing time as the next substrate to be processed can now be fed in while the previously processed item is being fed out. Another advantage is that the optional module makes it possible to integrate the processing machine in a continuous unidirectional process whereby the feeding in and out of the substrate to be processed is automated and the elapsed time is reduced. The optional module is preferably built such that it works in conjunction with the existing processing machine without any mechanical modifications being required to the existing processing machine.

An advantage related thereto is that the processing machine is not modified as such by the optional module, such that once the attached optional module has been removed, the latter can still be used as originally intended.

In a practical embodiment, the optional module consists of an attached feed-through table on which feed boards with substrate to be processed are being moved in one direction via slide guides by a feed-through mechanism, and whereby the feed-through mechanism of the optional module uses the original feed-out mechanism of the processing machine to obtain a feed in the opposite direction on the other side of the processing machine, resulting in a unidirectional feed-through of substrate.

An advantage related to this embodiment is that the feed- through mechanism must not have any source of power of its own, since the source of power of the original processing machine is used, which strongly simplifies the optional module and makes it independent of an energy source of its own.

The attached table of the optional module is preferably equipped with a height adjustor 26 to adjust the distance of the substrate to the inkjet nozzle for several substrate thicknesses, and it is provided with a locking system to steady the supporting table and its supports after the height has been set.

Also the safety sensor of the original printer is preferably used, situated on the front of the printer and which will stop the machine if a substrate is offered which exceeds the acceptable height. A horizontal lath on top of the printer inlet will be mechanically tilted if a substrate is too high, provoking a skip of the safety sensor.

The optional module also comprises a horizontal lath, but on the back of the machine, where the in-feed is now situated. A connecting belt, twisted 180°, couples the axis of rotation of the lath on the back to the axis of rotation of the lath on the front, such that an anticlockwise rotation of the axis for the lath on the back, when being pressed by a substrate which is too high, is transformed into a clockwise rotation of the axis for the lath on the front whereby the lath is being pressed there as well, which prompts the sensor on the front to stop the machine.

In order to better explain the characteristics of the invention, the following preferred embodiment of an optional module according to the invention is described by way of example only without being limitative in any way, with reference to the accompanying drawings, in which: figure 1 schematically represents a substrate processing machine in the form of an inkjet printer, seen in perspective;

figure 2 schematically represents the machine from figure 1 with an attached optional module for the guiding of a substrate according to the invention, seen in perspective;

figure 3 is a schematic side-view of a first phase A of the movement from a feed board to the printer;

figure 4 is a schematic side-view of a second phase B of the movement from a feed board to the printer;

figure 5 is a schematic side-view of a third phase C of the movement from a feed board to the printer;

figure 6 is a schematic side-view of a fourth phase D of the movement from a feed board through the printer.

Figure 1 schematically represents an existing inkjet printer 1, seen in perspective, with a housing 2, a feed carriage 3 on which has been provided a feed board 4 with a substrate to be processed 5, which is fed in and out of the machine on one and the same side of the machine by means of a closed toothed belt 6, driven by a motor 7 and running over a hub 8. The feed carriage 3 is secured to the toothed belt 5 in a fixed point and it slides over two carrying bars 10,11 making it possible to position the carriage at a required distance under an inkjet nozzle 12 situated in the housing 2. On the feed carriage is provided a bearing surface 13 for a feed board 4, which is adjustable in height. At the top of the feed opening in the printer 1 is situated a horizontally moving lath 14 which can come in contact with a safety sensor 15.

The working of the existing inkjet printer in figure 1 is very simple and as follows. A substrate 5, for example a piece of fabric, is manually placed on a feed board 4 and this feed board 4 is fixed on a feed carriage 3 by putting pins, not represented in the figures, in the openings in the feed carriage 3 provided to that end, after which the feed carriage 3 moves along the feed side of the printer 1 in the machine by means of a toothed belt 6 which is connected to the feed carriage 3 and which is driven in a certain direction by a motor 7.

This results in that the feed board 4 is brought in the right location, together with the substrate, in relation to the inkjet nozzle 12, after which the print is applied by the inkjet nozzle 12 in a movement opposite to that of the feed. If the substrate is too high, this substrate will come in contact with the lath 14 during the feed, which tilts and thus makes contact with a safety sensor 15 which in turn stops the printer 1.

Once the printing is finished, the feed board 4 will be taken out in the opposite direction by the same toothed belt 6 on the same side of the printer, after which the printed sample of the substrate is manually removed and replaced by a subsequent sample to be printed, after which the whole cycle is repeated.

The operator cannot start the manual operation of inserting a subsequent substrate until the previous one has been removed from the printer.

Figure 2 schematically represents the same inkjet printer as in figure 1, seen in perspective, whereby in this case, however, an optional module 16 according to the invention is attached, consisting of a feed table 17, a height adjustor 18 for the feed table 17, and a cable 19 guided under the feed table 17, with one far end of the cable being secured to a fixed point 20 of the toothed belt 6, and the other far end being secured to a fixed point 21 on the feed carriage 3, and whereby the cable 19 is guided over a cable pulley 22 and two or more guide rollers 23,24 situated outside the housing 2 of the printer 1. These guide rollers 23,24 can be mounted in a respective arrangement so as to ensure a perfect alignment and guidance.

A press-in lath 25 on top of the feed opening 32 on the back of the printer 1 is connected to the press-in lath 14 on top of the feed opening 26 on the front of the printer 1 via a cable 27 which is twisted 180°.

The cable 19 is provided with two catch teeth 28 and 29, and with a damper 30 in the form of a spring. A feed board 31 is situated on the feed table 17 in the direction of the feed opening 32 on the back of the printer 1 and is provided with two downward turned blocks 33,34 which are positioned above the cable.

The catch teeth 28,29 can be pressed and they have a standing edge on the side turned towards the machine 1 which can work in conjunction with said two blocks 33,34, as well as a rounded surface turned away from the machine, whereby the blocks can be pressed as soon as they come in contact with an obstacle along the rounded side.

The working of the attached optional module 16 according to the invention in figure 2 is as follows. A substrate 4 to be printed is now fed by moving a feed board 31 on which the substrate 4 to be printed moves to the opposite side of the printer 1 as that in figure 1 and in a direction opposite to that of the in-feed in figure 1.

The feed board 31 is now provided with two downward protruding rectangular blocks 33,34, each one on an opposite side of the feed board 31 and each one above the cable 19 respectively, and each one serving as a hook behind which the catch teeth 28,29 can mesh and can take along the feed board 31 in the direction of the back 32 of the machine 1 towards the front 26, whereby the front 26 used to be the feed-in and feed-out side of the machine before the attachment.

As soon as the nozzle has finished printing, the printed substrate 4 is fed further out of the printer, via the front of the machine, with the same catch tooth 29 as in figure 1. This continuous unidirectional direction of movement is made possible as the guiding system of cable 19 of the attached optional module 14 makes sure that, while the feed-out movement of the substrate 4 to the front 26 of the printer takes place, the feed-in movement of a subsequent feed board 31 is already being prepared as well.

As a safety measure, a press-in lath 14 is provided on top of the feed opening 26 on the front of the machine 1. This lath protects the machine in case a substrate 4 is presented which is too high for the machine 1 and which could damage the machine. The lath 14 will be tilted if the substrate 4 is too high, and as a result of the tilting, a sensor 15 is activated which stops the machine. This safety measure works when the substrate 4 is being fed via the front, as represented in figure 1, but it should also work when a substrate 4 which is too high is fed in via the feed opening 32 on the back of the printer 1, as is the case in the optional module 16. To that end, a second press-in lath 25 is provided on top in the feed opening 32 on the back, which is connected to the press-in lath 14 on top of the feed opening 26 on the front of the printer 1 via a cable 27 which is twisted 180°. If a substrate 4 which is too high is moved through the feed opening 32, the lath 25 will be pressed and, via the twisted cable, the lath 14 will be pressed as well, as a result of which the sensor 15 is activated and the machine 1 stopped.

Naturally, the machine 1 can be equipped with another security device than a moving lath, and also another security device must be completed in such a way that the protection also works if the in-feed takes place via the back instead of the front of the machine.

Figures 3 to 6 schematically and laterally represent the different phases A to D of the movement with which a feed board 31 is taken to the printer 1.

In figure 3, during phase 1, the feed board 31 is moved by the catch tooth 28 through a contact with the block 33, in the direction of the printer 1, whereby the catch tooth 28 is moved by the cable 19.

In figure 4, during phase B, block 34 meets the catch tooth 29 which moves in the opposite direction of the feed board 31.

In figure 5, during phase C, the catch tooth 29 hooks behind the edge of block 32 and moves together with the feed board 31 now in the direction of the printer 1, whereas the catch tooth 28 already returns in the opposite direction.

In figure 6, during phase D, the catch tooth 29 still hooks behind the edge of block 34 and thus moves the feed board 31 in and through the printer 1 via the opening in the back 32 and the opening 26 in the front of the printer 1.

The phases of movement represented in figures 3 to 6 can be illustrated as follows. Phase A starts when catch tooth 28 hooks behind the block 33 of feed board 31 and carries along the board in the direction of the printer 1, driven by the moving cable 19 onto which the catch tooth 28 is secured.

In the next phase B, the moving feed board 31 meets the catch tooth 29 moving in the opposite direction, driven by the same cable 19 but diverted round a cable pulley. Thanks to the contact of the rounded side of the catch tooth 29 with the block 34 at the bottom of the feed board 31, the catch tooth 29 is pressed and it slides under the block 34, after which the catch tooth 29 is locked to the block 34. In the next phase C, the standing side of the catch tooth 29 hooks behind block 34, and the direction of movement of the catch tooth 29 is reversed, such that the feed board 31 is moved further towards the printer 1. The catch tooth 28 which has provided for the drive up to now also returns in the reverse direction and is thus on its way to collect a new feed board so as to subsequently move it in the direction of the printer 1 again.

In the next phase D, the catch tooth 29 moves the feed board 31 through the printer 1, whereby an image is applied on the substrate by an inkjet nozzle, and after this operation the feed board 31 is fed out by the catch tooth 29 on the front of the printer 1. Naturally, one or several optional modules can be integrated for one or several, either or not different processing steps, in a single continuous feed-through process whereby a subsequent processing step can be automatically activated by the previous one. Naturally, the cables of the guiding systems of the original processing machine and of the optional module can be made as drive belts.

Of course, the catch teeth 28,29 for mechanically moving the feed board 31 can also be replaced by another locking system, such as for example an electromechanical lock.

The efficiency of the optional module is preferably further improved by routine adjustments to the control software of the existing printer, whereby the efficiency improvement can be increased from 60-100 percent to 80-120 percent or more, depending on the treatment process and the surface of the substrate to be processed. The present invention is by no means restricted to the embodiment described by way of example and represented in the figures, in this case an inkjet printer, but an optional module according to the invention can be made in all sorts of shapes and dimensions for any processing machine whatsoever with a one-sided feed-in and feed-out system for the substrate to be processed while still remaining within the scope of the invention.