ES1108831U - Ink recirculation systems and associated associated structures (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Ink recirculation system associated with a printing system comprising one or more printing bars, wherein each of the plurality of printing bars comprises one or more printing heads associated therewith, wherein each one of the print heads comprises a printhead ink duct extending between an ink inlet orifice and an ink outlet orifice, in which each of the printhead ink ducts extends further therein one or more nozzle plates through which the ink in the ink dye head can be controllably injected into a workpiece in response to one or more received signals, characterized in that the recirculation system of ink comprises: A feed tank for the accumulation of ink; A first intermediate deposit; A second intermediate deposit; An ink supply conduit between the supply tank and the first intermediate tank; An input distribution manifold, wherein the inlet distribution manifold comprises a conduit between the first intermediate reservoir and each inlet orifice associated with each of the recording heads; A recirculation manifold, wherein the recirculation distribution manifold comprises a conduit between each ink outlet orifice associated with each of the printing heads and the second intermediate reservoir; A recirculation circuit between the second intermediate tank and the first intermediate tank; y An overflow circuit between the first intermediate tank and the supply tank. (Machine-translation by Google Translate, not legally binding)

Description

INK RECIRCULATION SYSTEM

OBJECT OF THE INVENTION

The invention relates to the field of printing systems. In particular, the invention relates to ink recirculation systems.

BACKGROUND OF THE INVENTION

In most inkjet printers there is a unidirectional ink path that leads from a main tank or reservoir to feed a corresponding printhead. Since 2008, some printheads have been introduced that are configured to offer a displaceable ink path through the printhead, inside the injection chamber.

In some large-scale printing systems, basic embodiments of ink recirculation have been recently proposed, so as to reduce the accumulation of debris in the ink lines. However, the above recirculation configurations were prone to deposition and accumulation of waste at one or several points within the system.

We find some advantages in inkjet printers for ceramics, such as the removal of generated air, and / or the removal of waste or agglomerated ink particles. Such printers may offer an ink system that circulates the ink from the primary reservoir to the heads, and again to the primary reservoir.

It would be advantageous to provide an ink recirculation system and structure to reduce the negative effects of the ink that could otherwise be deposited or obstruct one or more parts of the ink system, for example the entry passages, the print heads and / or the ducts of recirculation.

It would also be advantageous to provide an ink recirculation system and structure that

inherently allows an improved ink circulation, in the entire range of operating cycles of a printing system. The development of such a system would constitute a great technological advance.

It would also be advantageous to provide an ink recirculation system and structure that reduces the complexity of the previous systems. The development of such a system and structure would include another technological advance.

BRIEF DESCRIPTION OF THE INVENTION

The ink recirculation system of the present invention is configured to allow a constant movement of the ink for a printing system, such as, but not limited to, an inkjet ceramic printing system. The controlled recirculation of the ink reduces the probability of deposit and accumulation of particles, in comparison with the systems of printing of previous tiles. Likewise, the ink recirculation system described here allows to eliminate the air inside the ducts associated with the ink supply, which reduces the number of production stops, so that the printing system can continue to operate, thus increasing productivity .

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of an example of an ink recirculation system associated with a printing system;

Figure 2 is a perspective view from above of an integrated intermediate distribution tank and a distributor structure associated with an example of an improved ink recirculation system;

Figure 3 is a detailed view of an integrated ink distribution tank;

Figure 4 is a partially cut away detailed view of an integrated ink distribution tank and a distribution manifold structure associated with an example of an improved ink recirculation system;

Figure 5 is a perspective view from below of an integrated ink distribution tank and a distribution manifold structure mounted on a printhead head module;

Figure 6 is a schematic view of a printhead associated with the improved ink recirculation system;

Figure 7 is a detailed partial schematic diagram of ink menisci associated with one or more nozzle plates for a printhead, and a pressure differential that is applied to the ink in the improved ink recirculation system; Y

Figure 8 is a partial process and instrumentation diagram for an exemplary embodiment of an ink recirculation system.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 1 is a schematic diagram of an example of an improved ink recirculation system 10 associated with a printing system 40. The improved ink recirculation system 10 is configured to create a complete ink recirculation path across an entire bar of print 200 (FIGURE 5). The improved ink recirculation system 10 may preferably be configured to allow anyone between the meniscus control 244 (FIGURE 7) for one or more nozzle plates 242 (FIGURE 7), the ink flow control over a whole bar of printing 200 in a whole range of operating cycles, and / or controlling the temperature of the ink 15 in all corresponding print heads 34, or any combination thereof.

As seen in Figure 1, a main reservoir 12 is configured to store a curable ink volume 15, and can typically be refilled. In addition, the main reservoir 12 typically comprises a level sensor and a temperature sensor, for example for any local or remote control. The main reservoir 12 may also preferably comprise mechanisms for anyone between stirring, mixing, casting or filtering. A primary ink supply circuit 14 extends from the main reservoir 12 to a first intermediate reservoir 18, that is to say feed, where the first intermediate reservoir 18 may preferably be located inside an integrated dispenser reservoir 16, that is, combined.

A main feed duct 22 extends from the bottom of the first intermediate reservoir 18 to a distribution manifold 26, for example located inside an integrated distributor 24. One or more printhead feed ducts 28, for example 28a à 28p, extend from the distribution manifold 26 and are each connected 30, to a corresponding ink inlet port 32 of a printhead 34 associated with the printing system 40, so that they supply, that is, inject in a controllable manner ink 15 on a piece 36, where the piece 36 may comprise, but not limited to, one or more ceramic tiles or other substrates 36.

While a single printhead 34 is illustrated in Figure 1 by way of illustration, it will be understood that a printing system 40 typically comprises a plurality of printheads 34, for example 34a to 34p, for controlled delivery of a corresponding color of ink 15 over the entire defined width 214 (FIGURE 5) of the printing system 40, for the controlled injection of ink 15 onto one or more pieces 36. For example, an example of a print bar 200 (FIGURE 5) may comprise a plurality of printheads 34a to 34p, such as, but not limited to, 10, 11 or 13 printheads 34, for the supply of one or more inks 15, and a printing system 40 may typically comprise a plurality of bars printing 200, for example 200a to 200h, for the supply of one or more colors of ink 15 or other fluids, such as, for example, but not limited to, background coatings, protective coatings, glitters, three-dimensional layers, alternative coatings, or any combination thereof.

Each of the print heads 34 also comprises a corresponding outlet duct 38, for example a flexible or rigid tube, which extends 40 towards a corresponding collector inlet 42, for example 42a, which is connected to a collection manifold, ie, recirculation, 44. A recirculation conduit 46 extends from the recirculation manifold 44 to a second intermediate reservoir 48, where the second intermediate reservoir 48 may also preferably be located within an integrated intermediate reservoir 16, that is, combined.

While the distribution manifold 26 and the collection manifold 44 may comprise assemblies separated from one another, in some embodiments of the system, such as visible in Figure 1, a single combined distributor 24 may comprise both the distribution manifold 26 as the collection manifold 44, correspondingly to a print bar 200 containing a plurality of print heads 34, for example 34a to 34p, for the delivery of a single color of ink to one or more substrates 36, for example tiles 36. For example, as visible in Figure 1, the distribution manifold 26 and the collector manifold 44 are integrated into a single distributor 24, such as on the basis of either between available space or tolerances, heat exchange desired between the distribution manifold 26 and the collector manifold 44, possibility of manufacturing, maintenance, or any combination thereof. Therefore, the example of the combined dispenser 24 visible in Figure 1 allows both the distributed supply of ink 15 to one or several printheads 34 and the distributed recovery of excess ink 15 from each of the one or more printheads. print 34.

It should be understood that, while the improved ink recirculation system 10 visible in Figure 1 comprises a single recirculation system 10 and the corresponding structures that are associated with a single print bar 200, a print system 40 may typically comprise a plurality of print bars 200, such as, but not limited to, four to eight print bars 200, where each of the print bars 200 may preferably comprise an improved ink recirculation system 10 corresponding thereto.

The exemplary improved recirculation system 10, visible in FIG. 1, comprises a primary recirculation circuit 50 that is connected to the primary inkjet circuit 14, where the ink 15 in the second intermediate reservoir 48 is recirculated again to the circuit of primary inkjet 14 through the first intermediate reservoir 18, without returning directly to the main reservoir 12.

As can also be seen in Figure 1, an overflow circuit 62 extends from the first intermediate tank 18 to the main tank 12, where the excess ink 15, beyond that which is injected, recirculated or accumulated in the first intermediate tank 18 , is configured to return to the main tank 12, and where the ink 15 can circulate in a controllable way from the main tank 12, through the primary ink supply circuit 14, to the first intermediate tank 18.

The primary ink supply circuit 14 visible in Figure 1 comprises an ink feed pump 48, and may preferably comprise a filter 46. In some embodiments, the supply circuit 14 may preferably comprise any between temperature measurement, temperature control and / or mass flow measurement.

Also, the recirculation circuit 50 typically comprises a recirculation pump 52, for example a vacuum pump, a sensor 288 (FIGURE 8), for example a pressure or vacuum sensor 288, and may further comprise a circuit filter of recirculation 54. In some embodiments, the recirculation circuit 50 may preferably comprise any between temperature measurement, temperature control and / or mass flow measurement.

It should be understood that, while the distribution manifold 26 and the recirculation manifold 44 are schematically illustrated in Figure 1, the design, size and shape of the manifold 26 and the recirculation manifold 44 can preferably be configured. based on one or more system parameters, so as to ensure that the pressure and ink flow are homogeneous for each of a plurality of print heads 34. It will also be understood that the design and configuration of the other components in the improved recirculation system 10 also influence the design requirements of the distribution manifold 26 and the recirculation manifold 44, so that the pressure and ink flow are inherently more homogeneous for each of a plurality of heads of print 34, even for collectors 26 and / or 44 having smaller diameters.

Figure 2 is a perspective view 100 of an integrated distribution tank 16 and distributor structure 24 associated with an example of improved ink recirculation 10. Figure 3 is a detailed view 140 of a first intermediate tank 18 and a second intermediate tank 48 associated with an integrated distribution tank 16 for an example of an ink recirculation system 10. In the present exemplary embodiment of the integrated distribution tank 16, the first intermediate tank 18 has a volume of approximately 650 ml, and may preferably be open to air, while the second intermediate reservoir 48 has a volume of approximately 350 ml.

As seen in Figure 2, an inlet opening 106 creates a conduit through which the ink of the supply circuit 14 enters 108 in the first intermediate reservoir 18. The inlet opening 106 may preferably be located in the lower part 136l of the first intermediate tank 18, and therefore fills upwards, towards the upper part 136u of the first intermediate tank 18.

As can be seen in FIG. 3, the lower surface 146 of the first intermediate tank 18 is preferably inclined, for example it has a steep slope profile, so as to avoid sedimentation, and / or favor circulation towards the distribution hole 184 ( FIGURE 4) which is connected to the main feed conduit 22, and that reduces the sedimentation of ink 15 in the first intermediate reservoir 18. The contour of the primary intermediate reservoir 18 may also preferably be rounded to a radius or otherwise rounded 148, to promote circulation and / or to prevent the sedimentation of the ink 15.

As seen in Figure 2 and Figure 3, the inlet connection 106 is generally located in the lower region 136u of the lower end of the first intermediate reservoir 18, where the incoming ink 15 is configured to fill the first intermediate reservoir 18 from the bottom up. The feed hole 22 is located at the bottom of the first intermediate reservoir 18, where the ink 15 located in the first intermediate reservoir 18 is configured to circulate down in the inlet manifold 26, to make the ink 15 available for delivery to printheads 34.

As can also be seen in Figure 3, the second intermediate tank 48 can preferably be placed in an integrated distribution tank 16, to receive the ink 15 that was supplied, but not used by the print heads 34. The recirculated ink 15 circulates towards the second intermediate reservoir 48 through a recirculation inlet port 188 (FIGURE 4) located at the bottom of the second intermediate reservoir 48. The second intermediate reservoir 48 also comprises a recirculation outlet port, a hole and a connection of recirculation outlet 110, through which the recirculated ink 15 is pumped 51 (FIGURE 1), and preferably filtered 54, for example through a recirculation circuit 50, for reintroduction into the primary ink supply circuit 14, where the recirculated ink 15 is reintroduced into the first intermediate tank 18. The lower surface of the second intermediate tank 48 may pref It is possible to be inclined, for example, it includes a steep slope profile, so as to prevent sedimentation, and / or promote circulation.

Figure 4 is a detailed partial cropped view 180 of an integrated distribution tank 16 and distributor structure 24 associated with an example of improved ink recirculation system 10. As visible in Figures 2, 3 and 4, a first sensor of Temperature 120 can preferably be set and positioned, for example through the upper part of the tank 104 (FIGURE 2), to detect the temperature of the ink 15, for example at a site close to the distribution hole 184. Also, a sensor of recirculation temperature 122 can preferably be set and positioned, for example through the high tank part 104 (FIGURE 2), to detect the temperature of the ink 15 returning to the recirculation tank 20, for example in a nearby location to the recirculation inlet port 188. The signals of one or the other between the first temperature sensor 120 or the recirculation temperature sensor 122 may preferably be used, for example together with the local or system control, to monitor and / or control one or more parameters, and may also offer a secondary indicator to determine or confirm the loss of the ink level, for example a temperature that goes beyond of a threshold or a threshold speed may indicate a loss of ink.

Fig. 5 is a perspective view from below of an integrated distribution tank 16 and distributor structure 24 mounted on a print bar frame assembly 201 for a print bar 200. The example of a print bar frame 201 visible in Figure 5 it comprises a print head frame 202, vertical end elements 204, 206, and a transverse frame element 208. The print head frame 202 typically comprises a plurality of defined print head access holes 210 in it through which each of a plurality of print heads 34, for example 34a to 34p, is fixedly mounted. As visible in Figure 5, the improved ink recirculation system is easily assembled and / or removed from the print bar frame 201.

The number and model 212 of the printhead access holes 210 typically corresponds to a desired printhead configuration, for example based on a specified arrangement 212 of one or more printhead manufacturers, thus creating an array. of printheads 34 for supplying the ink in a controllable manner over a desired width 214. For example, the specified arrangement 212 visible in Figure 5 comprises thirteen printhead access holes 210. In other embodiments, other numbers or Other arrangements may be provided, such as, but not limited to, ten or eleven printhead access holes 210.

Figure 6 is a detailed schematic view 220 of an example of a circulation printhead 34 that is configured for ink recirculation in the ink recirculation system 10. As visible in Figure 6, an ink duct 232 is defined between a printhead inlet port 32 and a printhead outlet port 38. The duct 232 moves beyond a plurality of controllable nozzles 222, for example 222a to 222k, where each of the nozzles has a nozzle plate 224 associated therewith, through which the ink 15 can be controlily injected onto a part 36. The example of the printhead 34 visible in Figure 6 involves a local control 228, for example mounted 230 at the printhead 34. The local control 228 further comprises an interface 232 that can be connected to the local print bar electronics 234 and the system control 236. The example of print head 34 visible in figure 6 is fixedly mounted on and extends through a print bar head plate 202.

As seen in Figure 6, the first intermediate reservoir 18 and the second intermediate reservoir 48 operate at pressures respectively 250 and 252, where a pressure differential 254 between the inlet pressure and the recirculation pressure 252 allows the system 10 to control the meniscus 244 to each of the nozzle plates 242 associated with a printhead 34. Also, the different pressures 250 and 252 in the first intermediate tank 18 and the second intermediate tank 48 are configured to create a desired ink flow 15 in the system 10.

While the improved ink recirculation system 10 may preferably be configured for a wide variety of circulation printhead 34, some current embodiments of the improved ink recirculation system 10 are configured for anyone between:

•

print heads 34 model No. 1001, available through Xaar PLC, from Cambridge, United Kingdom;

•

Printheads 34 model No. TEC CF1, available through Toshiba, Tokyo, Japan;

•

print heads 34 model no. SG-1204, available through Dimatix-Fuji; I

•

Print heads 34 serial number KM1024 available through Konica-Minolta, Tokyo, Japan.

Some of the current embodiments of the improved ink recirculation system 10 are configured for a range of ink flows through the distributor 24 ranging from 0 to 2,500 ml per minute (+++ please confirm the example of the range of collector flow rate +++), a range of ink flow through each print 34 from 0 to 250 ml per minute (+++ please confirm the example of collector flow range +++), and a temperature range at all Printheads 34 which varies between 35 degrees C and 50 degrees C.

Also, while the improved ink recirculation system 10 may preferably be configured for a wide variety of ink drop sizes supplied through the circulation print heads 34, some current embodiments of the improved ink recirculation system 10 are configured for specified drop sizes ranging from approximately 24 to 200 picoliters. For example, numerous circulation print heads 34 currently offer a drop size of 80 picoliters. For printing systems 40 that are configured to inject ink 15 onto ceramic tiles 36, there is often a specified minimum droplet size to obtain an effect upon firing of the injected ceramic tiles 36.

Figure 7 is a detailed partial schematic diagram 240 of ink meniscus 244 associated with one or more nozzle plates 224 for a printhead 34, and a pressure differential 254 throughout the distributor 24. The improved ink recirculation system 10 is configured to allow a constant ink movement 15 through each of the print heads 34, even inside the firing chamber, for example within the walls of the piezoelectric material, in any operating condition, by example from 0 to 100 percent of injection, for each and every drop injection on demand within one or more printheads 34. The constant controlled movement of the ink 15 is preferably configured to maintain the meniscus 224. For example , in a current system embodiment 10, the range of menisci in the nozzles is specified so that it is maintained between 0 mbar and -35 mbar. While the meniscus examples 244 are illustrated in Figure 7 as concave, it will be understood that the meniscus 244 can comprise a wide variety of forms, such as, but not limited to, any between concave, convex or more complex flat shapes, or Any combination thereof.

While the ink recirculation system 10 may preferably be configured for a wide variety of printing systems 40, an example of a current embodiment is associated with a digital inkjet printer on ceramics, which is preferably configured for use. Industrial intensive.

In inkjet printing of tiles, when a drop of ink 226 (FIGURE 6) to be printed on a ceramic piece is generated, an air volume similar to that of the ink drop is introduced. In inkjet printing systems on ceramics, it is necessary to remove this air through the same conduit as the ink feed. The presence of such air in an ink system often requires an operator to stop production.

Instead, the improved recirculation system 10 may preferably be configured to remove such air generated through a conduit other than that which supplies the ink 15, so that the improved printing system 40 can continue to function for longer periods between stops. of production.

While the main reservoir 12 in the improved ink recirculation system 12 may be the same as for a conventional ink supply system, the ink 15 is transferred, for example vertically, to the first intermediate reservoir 18, for example within a combined distribution tank 16, which can preferably be positioned vertically above the distributor 24 and the print heads 34. The ink 15 in the first intermediate tank 18, under a first pressure 250 (FIGURE 7), is transferred down through of the distributor 24, by the input manifold 26, where the ink 15 is supplied 30 to the print heads 34.

Contrary to the previous feed tank systems, which introduce the ink 15 to the top of a feed tank, the first intermediate tank 18 offers a robust, reliable and inexpensive mechanism for feeding ink 15 for the system 10. The first Intermediate reservoir 18 comprises an inlet opening 106 that enters the reservoir 18 in a lower region 136l, which inherently prevents sedimentation and / or blockage due to particles.

Also, the outlet port 114 (FIGURE 2, FIGURE 3) in the first intermediate tank 18 that feeds 116 towards the overflow circuit 62 is located in the upper region 136u of the first intermediate tank 18, where the level of the intermediate tank is configured to remain constant at any time during operation. The improved ink recirculation system 10 is configured to maintain the ink level 15 in the first intermediate reservoir 18, ensuring that, for any level of ink consumption, there is some amount of overflow 116. Therefore, during operation of the ink system, when there is little

or no inkjet 226, the amount of overflow 116 increases. On the other hand, the operation of the system where there is an ink consumption 226 which is at or near its maximum, for example at or near 100 percent of injection for most or all of the print heads 34 in a print bar 200, the overflow amount 116 (FIGURE 2) decreases to a minimum overflow threshold. For a print bar 200 that injects at or near 100 percent, the system 10 is still configured so as to have some overflow, even if the magnitude of the overflow 116 is much lower than for other ink supply flow rates.

In some embodiments, the improved ink recirculation system may be configured to offer an overflow level that is equal to 100 percent of the operating cycle for an example of print job that requires total recirculation from a print bar. 200, plus another percentage of the nominal workflow, for example, such as, but not limited to, 100 plus 10 percent. This configuration results in a robust system 10 that does not require a level instrument or circulation control associated with overflow maintenance 116.

Figure 8 is a partial process and instrument diagram 280 for an exemplary embodiment of an improved ink recirculation system 10, where the system 10 typically comprises a main ink feed tank 12 (FIGURE 1), a first intermediate tank 18, a second intermediate tank 48, an inlet manifold 26, a recirculation manifold 44, a feed pump 48, a recirculation pump 52, an overflow, i.e. a return pump 64, and a control system vacuum 282. The improved ink recirculation system 10 allows technically viable ink recirculation, and is also economical.

The input manifold 26 is fed with ink 15 by the first intermediate reservoir 18, where the input manifold 26 distributes and feeds the ink 15 upwardly to the different heads 34 in the same color. For example, in a current embodiment, the input manifold 26 distributes and feeds the ink 15 to a total of up to thirteen heads 34 for a printing system 40 having a single pass printing width of 700mm 214 (FIGURE 5). The waste ink 15 that is not injected 226 (FIGURE 6) leaves the printhead 34 through its outlet 38 and circulates through the recirculation manifold 46, which returns the ink 15 to the second intermediate reservoir 48.

The vacuum control system 282 illustrated in Figure 8 is configured to control or otherwise maintain the meniscus 244 in the print heads 34. An exemplary embodiment of the vacuum control system 282 may preferably comprise a mechanism, for example a venturi 284, to generate a negative pressure in the first intermediate tank 18, and a mechanism 286 to generate a vacuum in the second intermediate tank 48, for example that may preferably be produced by the recirculation pump 52, where the pump recirculation 52 also generates the recirculation flow. While the example of the vacuum control system 282 illustrated in Figure 8 may preferably be integrated with the print bar control 234, it will be understood that the vacuum control 282 may be independent, or it may be integrated with other components of a print bar 200 or system control 236, and may comprise any between electronic components, sensors, mechanical components, pneumatic components, or any combination thereof.

The recirculation pump 52 may preferably operate, as by the vacuum control 282, based on the output of the recirculation circuit sensor 288, for example a vacuum or pressure signal, so that the established meniscus 244 are maintained. . Otherwise, for example, if there is too much empty, the established meniscus 244 can be negatively affected.

The vacuum control 282, as configured by the local print bar control 234, typically receives a signal from the recirculation circuit sensor 288 and, based on the vacuum level in the recirculation circuit 50, the vacuum control 282 adjusts the vacuum pressure level 252 (FIGURE 7), with the recirculation pump 52 and / or a venturi 288 associated therewith, to maintain a suitable vacuum level 252 and the pressure differential 254.

In some current embodiments of the improved ink recirculation system 10, the first intermediate reservoir 18 is configured to absorb variations in ink level 15, where the system 10 is configured to ensure that the same amount of ink 15 always exists in the first intermediate tank 18, and where a pump 64 is connected to the first intermediate tank 18, where the pump 64 is configured to transfer a small amount of ink 15 from the first intermediate tank 18 to the main tank 12.

During the operation of the system, the ink 15 of the first intermediate reservoir 18 moves through the input manifold 26, and is distributed to each of the corresponding print heads 34, where the ink 15 moves 232 (FIGURE 6) more there each of the nozzle plates 242, for drop injection on request 226 (FIGURE 6). The non-injected ink 15 exits through the printhead exit 38 and travels 40 through the recirculation manifold 44 towards the second intermediate reservoir 48, where the ink 15 in the second intermediate reservoir 48 returns 52 to the first intermediate reservoir 18, and where a part of the return ink 15 in the first intermediate tank 18 exits 62, as an overflow, towards the main tank 12.

Therefore, the improved ink recirculation system 10 supplies a live supply of ink 15 to the print heads 34. The ink 15 circulates in the print heads 34, where it is available for injection through one or more plates of nozzle 224, based on a signal 238 received, for example through the print bar controller 234. Any excess ink 15 is recirculated again through the intermediate reservoirs 18, 48, so that the recirculation system of Enhanced ink allows a constant flow of ink, while preventing ink 15 from depositing and preventing sedimentation.

The pumps 48, 52, 64 for the improved ink recirculation system 10 are preferably sized based on the desired flow rates and operating pressures. Also, filters 46, 54 for the improved ink recirculation system 10 are preferably sized based on any between flow rates, operating pressures and maintenance intervals.

In the improved ink recirculation system, ink 15 passes through each firing channel, for example in front of each nozzle plate 224, where, if the controller electronics 234 gives the signal 238 to fire, the nozzle plate 224 fires, whereby one or several drops of ink (FIGURE 6) are injected 226, thus consuming a portion of the ink supplied 15. The residual ink 15 that is not injected 226 moves out of the head 34, and returns to the second intermediate deposit 48.

In some current embodiments of the system 10, the first intermediate tank 16 is open to air, and is configured to maintain an ink level 15, where the level is defined by the location of the overflow hole 114 in the upper region of the first intermediate tank 16, and where the ink circulation through the system 10 is configured to supply an amount of ink 15 that maintains the level in all modes of operation. One of the benefits of the system embodiments 10 that maintain at least some ink overflow to the main feed tank is that the improved system 10 does not require any level sensor to maintain an adequate level in the first intermediate tank 18.

If there were no overflow, the system 10 would typically recirculate and eventually consume the ink 15, so it would not maintain a homogeneous ink level and, consequently, would not maintain a homogeneous inlet head pressure 250.

The improved ink recirculation system 10 therefore allows precise management of the meniscus 242 that are established with the print heads 34, since the pressure in the ink path 232 is maintained at a constant level, thus reducing any variation in the geometry of the meniscus 242.

Alternative embodiments of the improved ink recirculation system 10 may further comprise a level sensor associated with the first intermediate reservoir 18, where the ink can be pumped controllably to the first intermediate reservoir 18 when this is required, or where the Excess ink is returned to main tank 12 when this is necessary. However, as described above, some of the preferred system embodiments 10 are configured to operate without such complexity.

Although the ink recirculation system and the methods of use are described herein in relation to an inkjet printing system on ceramics, the structures and techniques can be implemented for a wide variety of applications and scopes, or any combination of the themselves, according to wishes.

For example, an alternative ink recirculation system can preferably be configured for a wide variety of printing areas, such as for printing on substrates other than ceramics. Likewise, the improved recirculation system can preferably be configured for other fluid delivery areas, such as, but not limited to, any among inks, paints, solvents, adhesives, water, coolants or lubricants.

Therefore, although the invention has been described in detail with reference to a particular preferred embodiment, specialists with a normal experience in the art to which the invention belongs will recognize that various modifications and improvements can be made without departing from the spirit and the scope of the following claims.

Claims (17)

1. Ink recirculation system associated with a printing system comprising a or several print bars, in which each of the plurality of print bars comprises one or more print heads associated therewith, in which each of the print heads comprises a print head ink conduit that extends between an ink inlet port and an ink outlet port, in which each of the printhead ink ducts extends beyond one or more nozzle plates through which the ink in The printhead ink duct can be controllable injected into a workpiece in response to one or more received signals, characterized in that the ink recirculation system comprises: a feed tank for the accumulation of ink; a first intermediate deposit; a second intermediate deposit; an ink supply conduit between the feed tank and the first intermediate tank; an input distribution manifold, wherein the input distribution manifold comprises a conduit between the first intermediate reservoir and each inlet hole associated with each of the printheads; a recirculation manifold, wherein the recirculation distribution manifold comprises a conduit between each ink outlet port associated with each of the printheads and the second intermediate reservoir; a recirculation circuit between the second intermediate tank and the first intermediate tank; and an overflow circuit between the first intermediate tank and the feed tank.

2.

 Ink recirculation system according to claim 1, characterized in that the circulation of the ink through the ink recirculation system is configured so that there is at least some ink flow that returns to the main tank at any level of injection from the One or more printheads.

3.

 Ink recirculation system according to claim 1, characterized in that the

Ink circulation through the ink recirculation system is configured to reduce any between deposition or sedimentation of the ink.

Four.

 Ink recirculation system according to claim 1, characterized in that the first intermediate tank comprises a lower part and an upper part above the lower part, in which the ink supply circuit creates a conduit in the lower part to fill the First intermediate tank with ink that comes from the feed tank.

5.

 Ink recirculation system according to claim 1, characterized in that it further comprises:

an ink overflow hole extending from the top of the first intermediate tank, in which the overflow circuit is configured to transfer ink from the overflow hole of the first intermediate tank to the feed tank.

6.

 Ink recirculation system according to claim 1, characterized in that each of the nozzle plates is configured to establish an ink meniscus, and in which the recirculation circuit is configured to maintain the meniscus for each of the plates nozzle

7.

 Ink recirculation system according to claim 1, characterized in that the recirculation circuit is configured to maintain a specific pressure differential between the inlet manifold and the recirculation manifold.

8.

 Ink recirculation system according to claim 1, characterized in that the first intermediate tank is open to air.

9.

 Ink recirculation system according to claim 1, characterized in that the recirculation circuit further comprises a venturi, and a pressure source connected to the venturi, in which the venturi is configured to maintain a negative pressure in the recirculation circuit.

10.

 Ink recirculation system according to claim 1, characterized in that any one between the first intermediate tank and the second intermediate tank comprises

any between a sloping or contoured area to reduce any between deposition or sedimentation of the ink.

eleven.

 Ink recirculation system according to claim 1, characterized in that the system is configured to remove air within any one between the ink supply conduit, the recirculation circuit or the overflow circuit.

12.

 Ink recirculation system according to claim 1, characterized in that it further comprises a filter associated with any between the ink supply conduit or the recirculation circuit.

13.

Ink recirculation system according to claim 1, characterized in that the first intermediate tank and the second intermediate tank are combined in an integrated structure.

14.

 Ink recirculation system according to claim 1, characterized in that the inlet manifold and the recirculation manifold are combined in an integrated distributor structure.

fifteen.

 Ink recirculation system according to claim 1, characterized in that it comprises an integrated deposit structure which in turn comprises:

a main body having a lower region and an upper region, in which the main body comprises a first intermediate tank defined therein, and a second integrated tank defined therein, in which the first intermediate tank and the second tank intermediate extend from the upper region to the lower region; Y an upper cover that can be fixedly mounted on the upper part of the main body; in which an inlet port is defined in the lower region of the first intermediate reservoir for ink input from the feed container; in which a distribution hole is defined from the lower region of the first intermediate reservoir to transfer ink to each of the print heads; in which a recirculation hole is defined in the lower region of the second intermediate reservoir to receive ink from each of the print heads; in which a recirculation outlet port is defined in the second intermediate reservoir to transfer ink to a recirculation circuit; and in which an overflow outlet port is defined at the top of the first intermediate tank, to transfer ink to the feed tank.

16.

 Ink recirculation system according to claim 15, characterized in that the second intermediate tank is configured to operate with a negative pressure.

17.

 Ink recirculation system according to claim 15, characterized in that the

The integrated reservoir structure is configured to be mounted on top of the print heads, so that the ink level in the first intermediate tank allows a head pressure in relation to the print heads.