Filter and printhead rinsing system

Abstract

Filter and Printhead Rinsing System. One aspect of the invention relates to a printing system (10) for applying a coating product, comprising: a printhead (A1) for applying the coating product flowing in the normal flow direction; a single filter (F1) located upstream of the printhead; a plurality of valves and conduits for conveying the coating product and at least one rinsing fluid; said plurality of valves and conduits being arranged such that: the single filter can be rinsed with the rinsing fluid only in the direction opposite to the normal flow direction; the printhead can be rinsed with the rinsing fluid in the normal flow direction, the single filter and the printhead being able to be rinsed independently of each other. Figure to be published with the abstract: Figure 1

Description

Description Title of the invention: System for rinsing a filter and a head printing TECHNICAL FIELD OF THE INVENTION

[0001] — The technical field of the invention is that of the application by printing of a coating product on an object to be coated.

[0002] — The present invention relates in particular to a system for the application of a coating product on an object to be coated as well as several modes of operation system operation which allows in particular purging, rinsing, filling and the application of the coating product. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] — The personalization of decorations and coatings applied to objects becomes increasingly common. This is the case, for example, in the automotive industry for re- Vehicle bodywork coverings. This could, in this case, refer to coatings. of the monochrome, two-tone, or multi-tone painting type. Furthermore, the execution patterns, with a specific geometry, are potentially interesting for some other markets, particularly to visually differentiate two products based on their purpose or their manufacture. In this context, the coating industry has recently explored solutions involving "printing" paint using print heads, rather than spraying it with sprayers.

[0004] The paints used to produce these coatings by printing have viscosities on the order of 50 to 200 millipascal-seconds (mPas), and contain particles including the dimensions are on the order of microns. Thus, to apply such a product of re- garment using a printing technique, equipment of appropriate dimensions must be used. In particular, print heads with nozzles are used. feature a small diameter paint ejection orifice, on the order of 100 to 200 micrometers (µm), which is much smaller than the dimensions of an outlet orifice of a sprayers that are generally greater than 800 µm. Also used are filters whose characteristic filtering dimensions are on the order of 20 microns chromometers (µm). The role of such a filter is to block agglomerates or inhomo- coating product genes that could clog the nozzles of the head printing and thus ensure better print quality.

[0005] — The requirements concerning the quality of the printed coating imply regul- Thoroughly rinse the printing system components to remove any clumps. contents at the filter level or any residues that may accumulate at the level of the print head. It is a good idea to rinse these two parts using a The rinsing fluid should be applied at a pressure appropriate for the component. Filters can be rinsed at high pressure with forced air, while printheads are generally rinsed at lower pressures. Furthermore, it is best to avoid using air in the rinsing fluid for printheads, as its presence can dry and solidify the coating material being rinsed, particularly in the nozzles. Additionally, as the filter gradually becomes clogged, regular rinsing is necessary. For reasons of productivity and practicality, the same print head is generally used to apply different coating products, typically paints of different colors. It is therefore necessary to rinse the entire printing system to avoid unwanted mixing of coating products, while respecting the specific rinsing requirements of the various components. We know the state of the art in printhead rinsing techniques. For example, it is possible to use a cleaning station composed of several injectors to simultaneously clean several nozzles of a printhead. Furthermore, techniques are known for rinsing a filter mounted upstream of a print head in a coating application system. The filter is rinsed by a rinsing fluid with a two-way flow. The drawback of such techniques is that the time required to perform this double rinse is long and reduces printing productivity. We also know of the use of two filters in parallel, installed upstream of the print head. The application is carried out using only one of the two filters at a time, allowing the other filter to be rinsed or changed without interrupting the coating application. This results in a productivity gain. The drawback is that such a solution uses a more complex and less compact valve assembly to isolate the two filters, which hinders its integration into a printing system. Furthermore, these solutions for rinsing filters and printheads do not offer a printing system to rinse these two elements using a rinsing fluid whose pressure is adapted according to the element being rinsed, and to rinse the filter or printhead without also having to rinse the other element, or to rinse the entire printing system. Finally, document JP6979546B1 describes a printing system consisting of a set of sections, each section comprising conduits, valves, and a specific element to be rinsed, for example, a filter, a printhead, and a debubbling device. The sections (filter, printhead, and debubbling sections) of this system are arranged so that they can be rinsed independently of one another. others. In particular, three- or four-way valves are installed before and after each element to be rinsed (filter, print head and debubbler) to isolate the element in question and to convey the products according to the use (printing product, rinsing product or air). The drawback of such a system is that it requires a large number of valves to achieve the isolation functions of its various components. The arrangement of the different system components (valves, ducts, and elements) is therefore complex and bulky, which is incompatible with the compactness requirements for these systems. Furthermore, such a complex assembly increases the risk of component damage and premature failure, affecting the system's proper functioning. Therefore, such a system is also incompatible with the business requirements for the lifespan and reliability of the coating printing system. Furthermore, the use of a specific degassing unit — the debubbling unit — involves additional valves and conduits in the assembly which increases the system's bulk and the volume of fluid lost during a color change. There is therefore a need for a compact and reliable coating printing system that allows the filter and print head to be rinsed using a rinsing fluid whose pressure is adapted according to the element to be rinsed. Summary of the invention The invention provides a solution to the problems mentioned above by allowing the independent rinsing of a filter and a print head of a coating printing system. Furthermore, the printing system is compact and designed so that the rinsing of its components and the entire system can be carried out within a timeframe compatible with the productivity requirements for applying the coating product. The term "productivity constraints" refers to the constraints defined by the productivity objectives for the application of the coating product in question. This may involve a constraint on the printing execution time for one or more objects to be coated. A first aspect of the invention relates to a printing system for applying a coating product to an object to be coated, the printing system comprising: a print head to apply the coating product to the object to coat, the coating product flowing in a direction called direction normal flow; a single filter placed upstream of the print head to filter the product coating; a plurality of valves and conduits adapted to convey the product of re- garment and / or filter rinsing fluid and / or head rinsing fluid printing, said plurality of valves and conduits being arranged to form: a supply chain for coating products; a suitable filtration circuit to convey the coating product through the single filter in the normal flow direction and for convey the filter flushing fluid through the single filter only in the opposite direction to the normal flow direction; a suitable head circuit to convey the coating product and the printhead flushing product through the printhead in the direction of normal flow; a supply-filter isolation valve configured for: in a closed state, isolate the supply circuit from the circuit of filtration; in an open state, connect the supply circuit to the circuit of filtration; a filter-to-printhead isolation valve configured for: in a closed state, isolate the filtration circuit from the head circuit; in an open state, connect the filtration circuit to the printhead circuit; system in which the filtration circuit further comprises a filter flushing valve arranged opposite the filter-printhead isolation valve and a filter purge valve arranged opposite the supply-filter isolation valve, and in which the supply-filter isolation valve, the filter-printhead isolation valve, the filter flushing valve and the filter purge valve are two-way valves. By "independent operation," we mean that the filtration circuit and the printhead circuit are two separate circuits, isolated by one or more valves from among the plurality of valves. These two circuits can be used independently of each other. In other words, one circuit can be used without the other, or both can be used simultaneously without the use of one affecting the use of the other. For example, it is possible to rinse the filtration circuit without also rinsing the printhead circuit, which is isolated during the filtration circuit rinsing. It is possible to rinse the printhead without rinsing the filter. Furthermore, it is possible to rinse the printhead circuit and the... simultaneous filtration without the rinsing of one interfering with the rinsing of the other. Thanks to the invention, and in particular the use of isolation valves, the printing system allows the filtration circuit, including the filter, and the printhead circuit, including the printhead, to be used independently. It is therefore possible to rinse the filtration circuit and the printhead circuit separately and independently using two-way valves arranged opposite each other in pairs. The system according to the invention thus allows the use of a rinsing fluid with a different pressure, adapted to rinsing the various components of the printing system, and in particular to rinsing the filter and the printhead. Furthermore, when the isolation valves are open, it is possible to connect the different circuits together to print the coating product. Indeed, the printing system includes several circuits (circuit The supply, filtration, and printhead circuits are isolated from each other by means of isolation valves. These circuits are used for the circulation of different fluids. In this case, the filtration circuit is used for the isolated circulation of the filter rinsing fluid, and the printhead circuit is used for the isolated circulation of the printhead rinsing fluid. All three circuits also allow the coating material to circulate from the supply inlet to the printhead, passing through the filter. Thanks to the isolation valves and these independent circuits, it is possible to use one circuit in isolation from the others for a specific purpose. For example, the filtration circuit can be isolated during the printing process to rinse it and remove excess agglomerates without having to empty the other circuits, which contain the coating material ready for printing. Furthermore, since the filter and printhead are part of separate, independent, and isolated circuits, the filter can be rinsed with the appropriate rinsing fluid without also rinsing the printhead. It is therefore possible to rinse only the filtration circuit, and specifically the filter. This filter-only rinsing might be necessary, for example, when the filter is excessively clogged with coating compound, hindering proper application of the coating to the product being coated. Furthermore, since only one filter is used to filter the coating product, this filter is easy to integrate into the printing system, eliminating the need for a complex assembly requiring valves to direct the fluid to one filter or the other. This contributes to the compactness of the printing system. Moreover, since isolation, flushing, and drain valves are two-way valves, they offer advantages in terms of both compactness and reliability, as this type of valve has fewer moving parts. Their operation It also requires fewer controls, actuators, etc. This promotes a compact printing system while offering reliability and a lifespan compatible with business requirements. The printing system is all the more compact because it is advantageously devoid of a return circuit (from the print head) to the supply circuit to return the unused coating product (i.e. not ejected by the head) and be able to reuse it. The opposite arrangement of the valves promotes system compactness by limiting the number and / or length of the pipes, which also helps reduce the system's overall size. In particular, the section of pipe between two opposite valves, hereafter referred to as the common pipe section, can be short to minimize the volume shared by the two valves. Finally, filter and printhead rinsing can be performed within a timeframe compatible with the productivity requirements of the printing process. This is because the filter and printhead can be rinsed separately and simultaneously. Therefore, there is no need to wait for the filter to be rinsed before rinsing the printhead, or vice versa. Furthermore, the compact design of the printing system assembly ensures rapid circulation of the rinsing fluids. Since the filter is only rinsed in the opposite direction to the normal flow (i.e., the optimal direction for filter rinsing), a second rinse is unnecessary. The filter rinsing is thus completed quickly. Similarly, the printhead is cleaned only in the normal flow direction, allowing for rapid rinsing. In one embodiment of the printing system: the supply-filter isolation valve, the filter-head isolation valve printing, the filter flushing valve and the filter purge valve com- each take a seat and a spike designed to come against the seat ; the needle valve of the filter flushing valve and the needle valve The isolation filter-print head are aligned and pointing in the same direction. opposite each other towards a first common section of conduit; the needle valve of the filter purge valve and the needle valve of the isolation valve supply-filter are aligned and point in opposite directions towards a second section of common conduit. According to a development of this embodiment: the first section of common conduit separates the valve seat from filter rinsing and the filter-print head isolation valve seat and has a length between 1 mm and 10 mm; the second section of common conduit separates the seat of the purge valve filter and the seat of the isolation valve supply-filter and presents a length between 1 mm and 10 mm. This short distance between the opposing valves limits the amount of coating product needed to prime and fill the printing system, for example, during the system's initial use or when changing the coating product (typically a change of paint color). It also contributes to the compactness of the printing system. In one embodiment, the printing system further includes a filter rinsing inlet, the filter rinsing inlet being adapted to supply the filtration circuit with filter rinsing product, and wherein the filter rinsing valve is configured to: in an open state, connect the single filter to the filter flush inlet; in a closed state, isolate the single filter from the filter rinse inlet. It is therefore possible to control the supply of filter rinse product to the printing system towards the single filter and to prevent the circulation of the coating product towards the filter rinse inlet when the coating product is circulating in the printing system. In one embodiment, the filtration circuit further includes a filtration purge outlet, the filtration purge outlet being adapted to purge the filtration circuit with filter rinsing product, the filter purge valve being configured to: in an open state, connect the single filter and the filtration purge outlet; in a closed state, isolate the single filter from the filtration purge outlet. It is therefore possible to control the evacuation out of the printing system as filter rinse product after circulating in the filter and to prevent the circulation of the coating product towards the filtration purge outlet when the re-coat product circulates in the printing system. In one embodiment, the supply circuit comprises a supply inlet, a supply purge valve, and a supply purge outlet, the supply inlet being adapted to supply the circuit with coating product, the supply purge outlet being adapted to purge the supply circuit with coating product, the supply purge valve being configured to: In an open state, connect the supply inlet and the purge outlet. supply; In a closed state, isolate the supply inlet from the purge outlet. supply. It is therefore possible to control the supply of coating product in the supply circuit and to control the removal of the coating product from the supply circuit. In one embodiment, the printing system includes a fill-purge circuit and a fill-purge isolation valve, the fill-purge isolation valve being configured to: in an open state, connect the head circuit and the purge circuit of rem- pleating; in a closed state, isolate the head circuit and the purge circuit from rem- pleating. The filling purge circuit allows the coating product to be evacuated from the printing system after it has passed through the single filter. It is used, in particular, to expel air bubbles contained in the filtration circuit, for example, after cleaning the filter with pressurized air. According to one development of this embodiment, the printhead circuit further includes a printhead flushing valve arranged opposite the purge-fill isolation valve. The printhead flushing valve and the purge-fill isolation valve are advantageously two-way valves. Preferably, the printhead flush valve and the purge-fill isolation valve each include a seat and a needle designed to bear against the seat. The needle of the printhead flush valve and the needle of the purge-fill isolation valve are aligned and point in opposite directions toward a common third conduit section. Advantageously, the third common conduit portion separates the printhead flush valve seat and the purge-fill isolation valve seat and has a length between 1 mm and 10 mm. In one embodiment, the printhead circuit further includes a printhead rinse inlet, the printhead rinse inlet being adapted to supply the printhead circuit with printhead rinse fluid, the printhead rinse valve being configured to: In an open state, connect the print head and the print head rinse inlet printing; in a closed state, isolate the print head from the head rinse inlet printing. It is therefore possible to control the supply of printhead rinse product to the printhead and to prevent the circulation of the coating product to the printhead rinse inlet when the coating product is circulating in the printing system. In one embodiment, the printhead circuit further includes a printhead purge valve and a printhead purge outlet, the printhead purge outlet being adapted to purge the printhead circuit with printhead rinse aid and coating agent, the printhead purge valve being configured to: In an open state, connect the print head and the print head purge outlet. printing; In a closed state, isolate the print head from the print head purge outlet. printing. This allows the printhead rinse aid or coating agent to be discharged from the printing system via the printhead purge outlet after circulating through the printhead, or it allows the flow of the printhead rinse aid or coating agent to the printhead purge outlet to be blocked. Furthermore, if the printhead outlet ports are closed, closing the printhead purge valve will block the flow of these agents to the printhead. In one embodiment, the single filter comprises a mesh layer configured to filter the coating product, said mesh layer being arranged between two retaining layers. The filter is therefore of simple design and easy to integrate into the printing system. In one embodiment, the single filter has a first end and a second end, said single filter being arranged so that the coating product is conveyed along the axis of the filter by entering through the first end of the filter and exiting through the second end, and the rinsing fluid is conveyed along the axis of the filter by entering through the second end of the filter and exiting through the first end. Thus, the priming of the single filter with the coating product is carried out completely, without any air retention within the filter. Furthermore, the rinsing of the single filter is performed in such a way that the filter rinsing product rinses the entire filter space. In one embodiment, the system further includes a monitoring sensor. The monitoring sensor is preferably a pressure sensor located in the print head or between the print head and the print head purge valve. The system is thus monitored by means of the monitoring sensor, and its operation is adapted according to the data collected by the monitoring sensor. For example, when the sensor measures a pressure lower than a When the nominal level in the print head is reached, it alerts that the printing of the coating product is no longer being carried out under conditions that meet the specifications for the current printing, and the system is placed in an operating mode to rinse the filter clogged with agglomerates that hinder the proper circulation of the coating product. In addition to the characteristics mentioned in the preceding paragraphs, the system according to the first aspect of the invention may have one or more additional characteristics from among the following, considered individually or in all technically possible combinations: The supply-filter isolation valve is located upstream of the only filter; The filter-printhead isolation valve is located downstream of the single filtered. A second aspect of the invention relates to a method for controlling the printing system according to the first aspect of the invention, said control method comprising one or more of the following steps: Priming of at least part of the system using a coating product printing; Imprinting of the coating product onto the object to be coated; Print head rinsing; Rinsing the single filter. The printing system according to the invention can be controlled so as to prime the printing system with coating product, to apply the coating product to the object to be coated or to rinse one or more elements of the printing system. In one implementation mode, the printhead rinsing and single filter rinsing steps are implemented simultaneously by closing the supply-filter isolation valve and the filter-printhead isolation valve. This allows the printing system to be controlled so that the print head and the single filter are rinsed simultaneously and independently of each other. This implementation method saves time and therefore increases productivity. In one implementation mode, the piloting process includes a step of priming a coating product supply circuit and in which the steps of rinsing the single filter and priming the supply circuit are implemented simultaneously by closing the supply-filter isolation valve. This makes it possible to control the printing system so that the single filter is rinsed simultaneously and independently of the circuit priming. supply. This method of implementation saves time and therefore increases productivity. In one implementation mode, the piloting process includes a step of priming a coating product supply circuit and in which the printhead rinsing and supply circuit priming steps are implemented simultaneously by closing the filter-printhead isolation valve. This allows the printing system to be controlled so that the print head is rinsed simultaneously and independently of the priming of the supply circuit. This implementation method saves time and therefore increases productivity. In addition to the characteristics mentioned in the preceding paragraphs, the piloting method according to the second aspect of the invention may have one or more additional characteristics from among the following, considered individually or in all technically possible combinations: the filter rinsing fluid pressure is strictly greater than the head flushing fluid pressure; the pressure of the filter rinsing fluid is between 4 bar and 8 bar; the printhead flushing fluid pressure is between | bar and 3 bars; the single filter is rinsed by successively passing air and a liquid of rinsing, preferably with a solvent; the print head is rinsed by conveying a rinsing fluid, preferably a solvent. The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES The figures are presented for illustrative purposes only and are in no way limiting to the invention. Figure 1 is a fluidic diagram of a preferred embodiment of the system according to the invention. Figure 2 is a fluidic diagram of the system according to Figure 1, placed in a... operating method for priming a supply circuit. Fig. 3 shows a fluidic diagram of the system according to Fig. 1, placed in a... Priming operating mode of a filtration circuit. Figure 4 is a fluidic diagram of the system according to Figure 1, placed in a... operating mode of priming a head circuit. Figure 5 is a fluidic diagram of the system according to Figure 1, placed in a... printing operating mode of a coating product. Figure 6 is a fluidic diagram of the system according to Figure 1, placed in a... filter rinsing operating mode. Figure 7 is a fluidic diagram of the system according to Figure 1, placed in a... print head rinsing operating mode. Figure 8 is a fluidic diagram of the system according to Figure 1, placed in a... combined operating mode for system flushing. Figure 9 is a fluidic diagram of the system according to Figure 1, placed in a... simultaneous operating mode of filtration circuit rinsing 2 and priming. Figure 10 is a fluidic diagram of the system according to Figure 1, placed in a... simultaneous operating mode of head circuit flushing 3 and priming. Figure 11 is a fluidic diagram of the system according to Figure 1, placed in a... simultaneous operating mode for rinsing the filtration circuits and head, and priming. Figure 12 is a schematic representation of the assembly opposite each other. of two valves of the system. DETAILED DESCRIPTION Unless otherwise specified, the same element appearing on different figures has a unique reference. In the following text, and unless otherwise stated, the following definitions apply: "Coating product" means a compound of inorganic or organic nature which is intended to be applied to the surface of an object to be coated by means of a printing technique, in order to give it a desired functionality. By For example, in the case of the automotive industry, this could involve re- products Clothing for coloring and protecting vehicle chassis. More Specifically, the coating product can be paint, a primer, a varnish or a more viscous product such as glue or sealant; "object to be coated" an object on which one wishes to apply a coating product clothing in order to give it a desired functionality; "print head" an applicator device for printing the re- product The garment is placed on the object to be covered. The print head can be a head continuous jet printing, meaning it has open circuits permanently and does not contain a pressure coating product. The The print head can also be a droplet-type print head. the demand (or DOD, for "Drop on demand"). In order to control the application of the coating product, the ejection orifices (also called nozzles) of a DOD head are blocked by pilotable membranes. "filter" is a device for filtering the coating product that prevents agglomerates or inhomogeneities of the coating product from reaching the print head and thus preventing it from clogging. The filter may be in the form of a mesh small enough to block agglomerates but large enough to allow the particles of the coating product (typically the pigment particles of a paint) to pass through; "Valve" means a device for regulating the flow of the coating product and the filter and printhead rinsing fluids. A valve can be positioned so as to allow the rinsing fluid or coating product to pass through the valve, or to block the flow through this valve and divert the flow of the fluid or coating product to another path; "conduit" a connecting device between two elements of the system, for example between two valves, which allows the coating product or one of the rinsing fluids to be conveyed from one element to another; "Element" means a component of the system according to the invention. In this case, an element may refer to a valve, a filter, or a print head. "Circuit" means a series assembly of elements and conduits connecting the elements, the ends of which are constituted by an inlet and an outlet; "Normal flow direction" means the direction of flow of the coating product conveyed within the printing system so that the coating product can be applied to the object to be coated by means of the print head. In this case, the normal flow direction is that of the flow of the coating product from a source for supplying the coating product to the outlet of the print head, which applies the coating product; "Filter rinsing fluid" and "printhead rinsing fluid" are rinsing fluids specifically designed for rinsing the filter and the printhead, respectively. These may be the same rinsing product but used at different pressures depending on the component being rinsed. A rinsing fluid (filter or printhead) can be a rinsing liquid, preferably a solvent (capable of dissolving coating compound clumps) such as water. The filter rinsing fluid may also, contain air; "Supply entry" is an entry point in the system that serves to supply view the system as a coating product; "Purge outlet" is an outlet used to eject fluids from the system. rinsing and coating product, and to convey them to collectors recovery and processing; "Flushing inlet" is an inlet of the system used to supply the rinsing fluid system; "Isolation valve" a valve that allows two circuits to be isolated or connected in- dependent on each other; "system operating mode" a specific arrangement in which system valves are open or closed and which allows use the system according to a particular application. For example, the closure or Opening certain valves allows certain parts of the system to be isolated. or certain circuits to use the circuit for a specific application, such as filter rinsing, print head rinsing, system purging or the printing of the coating product. One aspect of the invention relates to a printing system for applying a coating product to an object to be coated. Figure [Fig.1] shows a fluidic diagram of system 10 according to a preferred embodiment of the invention. System 10 comprises an Al print head, a single F1 filter, and a plurality of valves and conduits. Preferably, the valves are two-way valves. Each two-way valve has a seat and a needle, the needle being designed to bear against the seat to close the valve. The print head is used to apply the coating product to the object to be coated by printing. The coating product is expelled from the print head A1 by pressurizing the coating product in system 10. The print head has a number of output holes for printing the coating product onto the object to be coated. These output holes are called A2 nozzles. The print head can have a plurality of A2 nozzles arranged in a line or in a grid pattern (several parallel lines). In the print head A1, the coating product flows in the normal flow direction, i.e. the coating product is conveyed to the inlet of the print head Al by means of a part of the valves and conduits and is expelled by the nozzles A2. The single F1 filter is used to filter the coating product before it reaches the head printing to prevent coating product agglomerates from clogging and blocking the nozzles A2 of the print head A1. Since the nozzle diameter is, for example, on the order of 100 to 200 micrometers (µm), the filter advantageously serves to filter any agglomerate or coating product particle whose characteristic size is, for example, on the order of 20 µm or more. In the printing system 10, the single filter F1 is therefore placed upstream of the print head A1 in the coating product flow path. The single filter is a sieve-type filter used in printing applications. Preferably, it is a dome-shaped filter with filter meshes of different characteristic sizes. In this case, the filter consists of three overlapping meshes. The upper and lower meshes have a characteristic size (i.e., the width of a mesh opening) between 100 µm and 900 µm, preferably between 350 µm and 550 µm. These two meshes therefore filter agglomerates larger than their characteristic size and also provide mechanical support for the middle mesh. The upper and lower meshes thus possess sufficient mechanical strength to prevent deformation of the filter, particularly the middle mesh, during normal operation and cleaning phases.The mesh of the intermediate mesh has a characteristic size between 1 µm and 100 µm, preferably between 10 µm and 30 µm, and serves to filter agglomerates larger than this characteristic size. It is this intermediate mesh that ensures the coating product does not clog the A2 nozzles of the A1 print head when it reaches them. This structure thus ensures good filtration performance thanks to the intermediate mesh, and maintains this intermediate mesh in a position that significantly limits the degradation of fluidic performance by limiting the deformation of the intermediate mesh through its position between the lower and upper meshes. The plurality of valves and conduits is arranged to create a circulation path for the coating product within system 10. The coating product is conveyed through some of the valves and conduits so that it flows in the normal flow direction. The assembly is designed so that the normal flow direction carries the coating product from filter F1 to print head Al. The multiple valves and conduits are also arranged to create a circulation path for the rinsing fluid for filter F1 and printhead A1. The rinsing fluid for filter F1 is called "filter rinsing fluid." The rinsing fluid for printhead A1 is called "printhead rinsing fluid." The filter rinsing fluid is conveyed by a part Valves and conduits are arranged so that it flows in the opposite direction to the normal flow. The printhead rinse fluid is conveyed through all the valves and conduits so that it flows in the normal flow direction. The flow of these two fluids in system 10 will be detailed later. Preferably, the ducts of the printing system 10 are as short as possible. This minimizes the distance the coating product must travel from one circuit to another. This arrangement of the printing system 10 is therefore optimized to limit waste and loss of coating product during the refilling of the elements and ducts of the printing system 10. Furthermore, this arrangement improves the compactness of the system 10 and thus its integration into a coating printing installation. Preferably, the ducts are 200 mm or less in length. As illustrated in [Fig.1], system 10 also has three separate inputs and four separate outputs. The inputs of system 10 are: a PI supply input, a P2 filter rinse input and a P3 printhead rinse input. The outputs of system 10 are: a supply purge output Ol, a filtration purge output O2, a printhead purge output O3 and a filling purge output O4. The plurality of valves and conduits is further arranged to form three different circuits that can be isolated from each other to convey the re-clothing and rinsing products in system 10. These three circuits are: a supply circuit |, a filtration circuit 2 and a head circuit 3. The printing system 10 may, in addition, include a fourth filling purge circuit 4. These four circuits are interconnected by means of isolation valves. Supply circuit 1 is connected to filtration circuit 2 by a supply-filter isolation valve V12. Filtration circuit 2 is connected to printhead circuit 3 by a filter-printhead isolation valve V23. Printhead circuit 3 is connected to the purge-fill circuit 4 by a purge-fill isolation valve V43. Supply circuit 1 includes: supply inlet Pl, supply purge valve V1, first conduit C1, second conduit C2, third conduit C3 and supply purge outlet O1. In supply circuit 1, the first conduit C1 connects the supply inlet P1 to the supply-filter isolation valve V12; the The second conduit C2 connects the supply-filter isolation valve V12 to the supply purge valve V1; and the third conduit C3 connects the supply purge valve V1 to the supply purge outlet O1. Alternatively, as long as the third conduit C3 connects the supply purge valve V1 to the supply purge outlet OI, the first conduit C1 can connect the supply inlet O1 to the supply purge valve V1, and the second conduit C2 can connect the supply purge valve V1 to the supply-filter isolation valve V12 without altering the operation of the printing system 10. The filtration circuit 2 includes: the filter rinse inlet P2, a filter rinse valve V2, a filter purge valve V3, the single filter F1, a fourth conduit C4, a fifth conduit CS, a sixth conduit C6, a seventh conduit C7 and the filtration purge outlet O2. In filtration circuit 2, the fourth conduit C4 connects the filter backwash inlet P2 to the filter backwash valve V2; the fifth conduit CS connects the filter backwash valve V2 to the single filter F1; the sixth conduit C6 connects the filter F1 to the filter purge valve V3; and the seventh conduit C7 connects the filter purge valve V3 to the filtration purge outlet O2. Therefore, relative to the normal flow direction in filtration circuit 2, the filter backwash valve V2 is positioned downstream of the single filter F1, and the filter purge valve V3 is positioned upstream of the single filter F1. The single filter F1 is arranged in series in the filtration circuit 2, that is to say that the flow axis of the filter rinsing product or the coating product in the single filter is parallel to the flow axis of said product in the filtration circuit 2. In other words, the single filter having two ends for the inlet and outlet of the products within it, the axis of the filter indicated by its two ends is aligned with the flow axis of the coating or filter rinsing products in the filtration circuit 2. The printhead circuit 3 includes: the printhead rinse inlet P3, a printhead rinse valve V4, a printhead purge valve VS, the printhead A1, an eighth conduit C8, a ninth conduit C9, a tenth conduit C10, an eleventh conduit C11, a twelfth conduit C12, the printhead purge outlet O3. In printhead circuit 3, the eighth conduit C8 connects the printhead flush inlet P3 to the printhead flush valve V4; the ninth conduit C9 connects the printhead flush valve V4 to the printhead filter isolation valve V23; the tenth conduit C10 connects the printhead filter isolation valve V23 to the printhead A1; the eleventh conduit C11 connects the printhead print head A1 to print head purge valve V5; and the twelfth conduit C12 connects print head purge valve VS to print head purge outlet O3. Relative to the normal flow direction in print head circuit 3, print head rinse valve V4 is therefore positioned upstream of print head A1 and print head purge valve VS is positioned downstream of print head A1. The filling purge circuit 4 includes a thirteenth conduit C13 and the filling purge outlet O4. In the purge-fill circuit 4, the thirteenth conduit C13 connects the purge-fill isolation valve V43 to the purge-fill outlet O4. When the supply purge valve V1 is open, it allows the flow of products between the supply inlet PI and the supply purge outlet O1. The term "products" refers to both the coating product and the rinsing products. This sequence allows, in particular, for the rapid filling of the coating, the first line C1, and the second line C2. When the supply purge valve V1 is closed, this flow is not possible. The supply purge valve V1 therefore allows the supply inlet P1 and the supply purge outlet O1 to be connected or isolated. In particular, the supply purge valve V1 allows the flow of the coating product in the supply circuit 1 to be blocked. When the filter rinse valve V2 is open, it allows the flow of products between the filter rinse inlet P2 and the single filter F1. When the filter rinse valve V2 is closed, this flow is not possible. The filter rinse valve V2 thus allows the single filter F1 to be connected to or isolated from the filter rinse inlet P2. Specifically, the filter rinse valve V2, in the open position, allows the flow of the filter rinse product into the filtration circuit 2 from the filter rinse inlet P2, and, in the closed position, blocks the flow of the coating product to the filter rinse inlet P2. When the filter purge valve V3 is open, it allows the flow of products between the single filter F1 and the filtration purge outlet O2. When the filter purge valve V3 is closed, this flow is not possible. The filter purge valve V3 therefore allows the single filter F1 to be connected to or isolated from the filtration purge outlet O2. Specifically, the filter purge valve V3, in the open position, allows the flow of filter rinsing product to the filtration purge outlet O2, and, in the closed position, blocks the flow of coating product to the filtration purge outlet O2. When the printhead rinse valve V4 is open, it allows the flow of products between the printhead rinse inlet P3 and the printhead Printhead A1. When the printhead rinse valve V4 is closed, this circulation is not possible. Closing the printhead rinse valve V4 also helps maintain the coating pressure in the printhead A1. The printhead rinse valve V4 therefore allows the printhead A1 and the printhead rinse inlet P3 to be connected or isolated. Specifically, in the open position, the printhead rinse valve V4 allows the printhead rinse product to circulate through the printhead circuit from the printhead rinse inlet P3, and in the closed position, it blocks the circulation of the coating product to the printhead rinse inlet P3. When the printhead purge valve V5 is open, it allows the flow of products between the printhead A1 and the printhead purge outlet O3. When the printhead purge valve VS is closed, this flow is not possible. Closing the printhead purge valve V5 also maintains the coating product pressure in the printhead A1. The printhead purge valve V5 therefore allows the printhead A1 and the printhead purge outlet O3 to be connected or isolated. Specifically, the printhead purge valve VS, in the open position, allows the flow of the printhead rinse product or coating product in the printhead circuit 3 to the printhead purge outlet O3, and, in the closed position, blocks the flow of the coating product or printhead rinse product to the printhead purge outlet O3.Furthermore, when the VS print purge valve is closed and the A2 nozzles of the A1 print head are also closed, then the flow of coating product and print head rinse product to the A1 print head is blocked. The supply-filter isolation valve V12 is placed opposite the filter purge valve V3 so as to allow the supply circuit 1 to be connected to the filtration circuit 2 at the level of the sixth conduit C6. The term "placed opposite" refers to an assembly of two valves whose needles are aligned (i.e., oriented in the same direction). Preferably, the needles of the two valves in question point in opposite directions, towards each other, towards a common section of conduit. The V12 filter supply isolation valve and the V3 filter purge valve are arranged so that their respective seats are separated by the common section of conduit (C6). The length of this common section of conduit is advantageously between 1 mm and 10 mm. The spacing between the two seats is, for example, 5 mm. The spacing between the two seats can, in particular, be equal to the diameter of the seats. Compared to the normal flow direction, the supply-filter isolation valve V12 is therefore placed, in the printing system 10, upstream of the single filter F1 and downstream of the supply inlet PI. The supply-filter isolation valve V12 allows the supply circuit and the filtration circuit 2 to be isolated when this valve is closed. When closed, product flow occurs only between the first line C1 and the second line C2 if the supply purge valve V1 is open. Conversely, when this supply-filter isolation valve V12 is open, the two circuits are connected, and the different products can flow from one to the other. Product flow is then possible between the first line C1, the second line C2, and the sixth line C6. Furthermore, product flow in the second line C2 can be stopped if the supply purge valve V1 is closed. More generally, the V12 supply-filter isolation valve is arranged to be as close as possible to the V3 filter purge valve. The filter-printhead isolation valve V23 is positioned opposite the filter flushing valve V2 to allow connection of the printhead circuit 3 to the filtration circuit 2 at the fifth conduit CS. Preferably, the seats of these valves are separated by a common conduit section (CS) with a length between 1 mm and 10 mm, for example, 5 mm. The spacing between the two seats can, in particular, be equal to the diameter of the seats. Relative to the normal flow direction, the filter-printhead isolation valve V23 is therefore located, in the printing system 10, downstream of the single filter F1 and upstream of the printhead A1. The V23 printhead-filter isolation valve isolates the filtration circuit 2 and the printhead circuit 3 when closed, allowing product flow only within their respective circuits. Conversely, when the V23 printhead-filter isolation valve is open, the two circuits are connected, and different products can flow between them. Product flow is then possible between the fifth line C5, the ninth line C9, and the tenth line C10. Furthermore, product flow in the ninth line C9 can be stopped if the printhead flush valve V4 is closed. Flow can also be stopped in the tenth line C10 if the printhead purge valve VS is closed and the A2 nozzles of printhead A1 are not open. More generally, the V23 filter-printhead isolation valve is arranged to be as close as possible to the V2 filter flushing valve. Preferably, the V23 printhead-filter isolation valve is open to allow the coating product to circulate in the printing system 10. from the supply input P1 to the head circuit 3. In the presence of the purge-fill circuit 4, the purge-fill isolation valve V43 is advantageously positioned opposite the printhead flush valve V4 so as to allow the purge-fill circuit 4 to be connected to the printhead circuit 3 at the ninth conduit C9. Preferably, the seats of these valves are separated by a common conduit section (C9) of length between 1 mm and 10 mm, for example, 5 mm. The spacing between the two seats can, in particular, be equal to the diameter of the seats. The purge-fill isolation valve V43 isolates the purge-fill circuit 4 from the printhead circuit 3 when closed. Conversely, when open, the two circuits are connected, allowing different products to flow between them. Specifically, products can circulate between the ninth line C9 and the thirteenth line C13 when the purge-fill isolation valve V43 is open. Therefore, the purge-fill valve V43 connects or isolates the printhead A1 from the purge-fill outlet A4. More generally, the V43 purge-fill isolation valve is also arranged to be as close as possible to the V4 print head flush valve. Compared to the normal flow direction, the V43 purge-fill isolation valve is therefore placed, in the printing system 10, upstream of the Al print head. Therefore, opening or closing the various isolation valves allows the various products to circulate in the different parts of system 10 from an inlet to an outlet of this system 10. The advantage of an assembly of opposing two-way valves is to reduce the internal volume of the printing system 10. This helps to reduce losses of re-clothing product (and therefore save on coating product), particularly during a rinsing phase before priming the printing system 10 with a new re-clothing product. Furthermore, reducing the internal volume of the printing system allows for a system that meets business requirements in terms of compactness. Indeed, the use of opposing valves reduces the number or length of the various conduits in the system. In particular, the spacing between two opposing valves, formed by a common section of conduit, is reduced thanks to this specific valve assembly. Finally, the opposite assembly of the valves avoids creating a dead zone in system 10. A dead zone can be defined as an area where the fluids and The circulating products have a very low velocity compared to the main flow, and therefore cleaning (by mechanical action of the fluid) is ineffective. In particular, the facing assembly ensures that the common section of conduit is not a dead zone. Finally, the opposite arrangement makes the valves more easily accessible to an operator. Their installation in the system and their maintenance are therefore simplified. For example, the opposite arrangement allows the valves to be assembled on only two opposite faces of the system body (or frame). An illustrative diagram of a two-valve assembly 100 is shown in [Fig. 12]. A first valve 110, connected to a conduit 113, comprises a seat 111 and a needle 112. A second valve 120, connected to a conduit 123, comprises a seat 121 and a needle 122. The first valve 110 and the second valve 120 are positioned opposite each other so that the needle 112 of the first valve 110 points towards the needle 122 of the second valve 120, and vice versa. The two needles 112 and 122 are therefore directed towards each other. A common conduit 130 is connected to the first valve 110 and the second valve 120. This conduit 130 includes a portion of common conduit 131 located between the first valve 110 and the second valve 120. In an undifferentiated manner, assembly 100 of [Fig.12] can correspond to the assembly of the supply-filter isolation valve V12 with the filter purge valve V3, to that of the filter-printhead isolation valve V23 with the filter flush valve V2 or to that of the purge-fill isolation valve V43 with the printhead flush valve V4. The different configurations in which the valves are actuated—that is, whether they are positioned open or closed—allow the system 10 to be placed in a specific operating mode for a predefined purpose. These different operating modes will be described later in the text. As illustrated in [Fig. 1], the supply circuit 1 is further arranged to allow the coating product to circulate in the normal flow direction. More specifically, the normal flow direction requires the coating product to circulate from the supply inlet P1 to the supply-filter isolation valve V12 or to the supply purge outlet O1. Filtration circuit 2 is further arranged to allow the coating product to circulate in the normal flow direction. The normal flow direction is from the filter purge valve V3 to the filter rinse valve V2. Filtration circuit 2 is also designed to carry the filter rinse fluid flowing in the opposite direction to the normal flow direction, i.e., from the filter rinse fluid inlet P2 to the purge outlet. O2 filtration. The printhead circuit 3 is further arranged so that the coating product can be conveyed in the normal flow direction, from the filter-printhead isolation valve V23 to the print purge outlet O3. The printhead circuit 3 is also designed to convey the filter rinse fluid in the opposite direction to the normal flow direction from the printhead rinse fluid inlet P3 to the print purge outlet O3. The filling purge circuit 4 is further arranged so that the coating product can be conveyed in the normal flow direction, i.e., from the filling purge isolation valve V43 to the filling purge outlet O4. This fourth circuit serves, among other things, to allow the degassing of the printing system 10. This degassing can take place, for example, before the application of the coating product, to purge the various circuits of any air bubbles that could degrade the application conditions of the coating product. Degassing can also take place when filling the various circuits with coating product, for example, after rinsing the single filter or the print head.This filling purge circuit 4 eliminates the need for a bulky dedicated debubbling module, whose mechanical components for its actuation would negatively impact the reliability and lifespan of the printing system 10. System 10 also includes monitoring sensors (not shown in the figures). These sensors are placed in the circuit to monitor the operating status of System 10. They are used to detect malfunctions in the components of System 10. These sensors may measure pressure at various points in the system. Preferably, they are pressure sensors to measure the pressure of one of the products flowing through filter F1 and the pressure of one of the products flowing through printhead A1. Thus, when a pressure anomaly is detected, action can be taken to correct it. For example, if a measurement detects a pressure defect in the coating product at printhead A1, this may mean that filter F1 is too clogged to ensure the required printing pressure is maintained in printhead A1.A cleaning action on filter F1 would therefore be necessary to correct this pressure fault. It is possible to place a pressure sensor upstream of the filter and another pressure sensor downstream of the filter to identify filter saturation. It is also possible to place the sensors upstream of the supply inlet to detect a variation in the monitored variable in system 10. System 10 also includes an access hatch (not shown in the figures) which allows easy access to the single filter and quick replacement. compatible with productivity constraints when it becomes unusable or damaged. The valves of system 10 are advantageously pneumatic valves. A "pneumatic valve" is a valve operated by compressed air acting on a piston, which in turn pulls on a needle valve, thus allowing the passage of a fluid. A pneumatic valve is therefore pneumatically controlled to limit the use of electric valves due to the environment in which the printing system 10 is used, the operating environment being, for example, an explosive atmosphere (ATEX). The pneumatic valves can be controlled by a programmable logic controller (PLC) (not shown) during the printing, rinsing, and priming actions of the printing system 10. This control can also be performed according to instructions stored in memory to, for example, execute a printing sequence including the printing, rinsing, and priming actions. The PLC can be integrated into the printing system 10. Preferably, the PLC is located outside the printing system 10. Each pneumatic valve can be connected to a solenoid valve that provides electronic control of the pneumatic valves. The solenoid valves can be included in the printing system or be outside of the printing system. The control of the valves via the solenoid valves is implemented by instructions stored in memory, or transmitted by an electronic board or the PLC (not shown), whose role is to supervise the elements of the printing system. This allows for autonomous and automated operation of the printing system 10. For example, it is possible to place the system 10 in a desired operating mode based on data collected by the monitoring sensor. The electronic board can also control the A2 nozzles of the print head Al for ejecting the coating product. The control of the A2 nozzles by the electronic board can be based on the phase of the printing sequence. The control of the A2 nozzles can also depend on information about the position of the printing system relative to the object to be coated. The invention also relates to a method for controlling the printing system 10. The control method allows the various valves of the printing system 10 to be actuated in order to place the different circuits in a specific configuration to implement an operating mode of the printing system 10. The piloting process includes a priming step with coating product on at least part of the printing system 10. This step places the printing system 10 into a so-called purge and fill mode of the supply circuit 1, the filtration circuit 2, or the printhead circuit 3. The priming step can be implemented so as to successively place the printing system 10 into the three so-called purge and fill operating modes. of a circuit, as described below. In this priming step, it is also possible to place the system 10 in a single operating mode, known as purging and filling, of a single circuit during the priming step. Indeed, depending on the previous operating mode in which the printing system 10 was placed, and depending on the subsequent operating mode in which the printing system 10 will be placed, it may turn out that only one of the purging and filling operating modes is necessary. The same reasoning applies to a combination of two of the three purging and filling operating modes mentioned above. This operating mode can be implemented during the initial commissioning of the printing system 10, after rinsing the single filter F1 or the print head Al or to perform a coating product change in order to prime the printing system 10 with a new coating product. The process of controlling system 10, by means of instructions from the electronic card or the PLC, allows the system 10 to be placed in a first operating mode called purging and filling of the supply circuit 1. This is also referred to as priming the supply circuit 1. The priming of the supply circuit | can, moreover, be implemented during a first sub-step of priming the supply circuit 1, of the priming step of the control process. This first operating mode of purging and refilling with re-coat product of the supply circuit 1 is illustrated in Fig. 2]. The objective of this first mode of operation is to isolate the supply circuit | in order, firstly, to purge it of any residues of coating product from a previous application, of undesirable particles, and to purge the air contained in the conduits and the various elements of the supply circuit 1, then, secondly, to fill it with re-coat product. In the priming substep of the supply circuit 1, the valves of system 10 are then actuated so that the supply purge valve V1 is open and the supply-filter isolation valve V12 is closed. Supply circuit 1 is then isolated from the other circuits. The flow of the coating product therefore occurs only within supply circuit 1. The printing system 10 can then be supplied with coating product to perform the purge and fill the supply circuit 1. The circulation of the coating product is in the normal flow direction, from the supply inlet P1 to the supply purge outlet O1. In this first mode of operation, the first conducts C1, the second Conduit C2, the third conduit C3, and the supply purge valve V1 can be filled with coating product. Preferably, supply circuit 1 is filled with coating product until it exceeds the supply purge valve. System 10 is thus placed in an operating mode such that the supply circuit is purged of any residual rinsing fluids and coating product that need to be expelled from supply circuit 1. The purging is carried out by the coating product supply, which, by circulating from the supply inlet P1 into supply circuit 1, expels the unwanted residues through the supply purge outlet O1. This ensures that only the coating product is present in the circuit. supply |, without impurities that would degrade the quality of the coating product. This also ensures that the supply circuit 1 is purged of any air bubbles that could degrade the print quality. In this operating mode, the coating product flows in the normal direction. During the pilot process priming stage, the printing system 10 is then placed in a second operating mode called purging and filling with coating product of the filtration circuit 2. This is also referred to as priming the filtration circuit 2. The priming of the filtration circuit 2 can, moreover, be implemented during a second sub-step of priming the filtration circuit 2, of the pilot process priming stage. This second operating mode of purging and filling with re-coat product of the filtration circuit 2 is illustrated in [Fig.3]. The objective of this second operating mode is, firstly, to purge any remaining coating or rinsing products from a previous application, as well as any unwanted particles. This second operating mode also allows for purging the filtration circuit 2 of any air pockets, which may be due to a previous rinsing of the single filter F1 or to the fact that the printing system 10 has not yet been used. This is referred to as degassing the printing system 10. Secondly, the objective is to fill the ducts, valves, and the single filter F1 of the filtration circuit 2 with coating product. In the priming substep of the [filtration 2] circuit, the valves of system 10 are then actuated so that the supply-filter isolation valve V12, the filter-printhead isolation valve V23 and the purge-fill isolation valve V43 are open, and the supply purge valve V1, the filter purge valve V3, the filter rinse valve V2, the printhead purge valve V5 and the printhead rinse valve V4 are closed. The filtration circuit 2 is connected to the supply circuit 1, the printhead circuit 3 and the filling purge circuit 4. In this operating mode, the printhead Al is kept isolated from the other circuits by the closing of the print purge valve V5 and the closing of the nozzles A2. The printing system 10 can then be supplied with coating product to perform the purging and fill the filtration circuit 2. The coating product circulates in the normal flow direction, from the inlet supply Pl up to the O4 filling purge outlet. In this second operating mode, the first conduit CI, the sixth conduit C6, the fifth conduit C5, the ninth conduit C9, the thirteenth conduit C13, the supply-filter isolation valve V12, the single filter F1, the filter-printhead isolation valve V23 and the purge-fill isolation valve V43 can be filled with coating product. System 10 is then placed in an operating mode such that the filtration circuit 2 is purged of residues from the filter rinsing fluid and any coating product that must be expelled from the filtration circuit 2. The purging is carried out by the coating product supply, which, by circulating from the supply inlet O1 through the supply circuit 1 and the filtration circuit 2 to the supply purge circuit 4, expels the undesirable residues through the filling purge outlet O4. This ensures that only the coating product is present in the filtration circuit 2, without impurities that would degrade the quality of the coating product. It also ensures that the filtration circuit 2 is purged of any air bubbles that could degrade the print quality. In this operating mode, the coating product flows in the normal direction of flow.In particular, the O4 fill purge outlet is used to purge the air bubble that naturally forms in the ninth conduit C9. The ninth conduit C9, the V43 fill-purge valve and the thirteenth conduit C13 have the same role as a debubbling module but offer better compactness, reliability and lifespan. Alternatively, the filtration circuit 2 priming substep can consist of two operations: a first operation to pressurize the printing system 10 from the supply inlet P1 to the purge-fill isolation valve V43; a second operation to purge the ninth conduit C9. Compared to the filtration circuit 2 priming substep described previously, this alternative allows the filtration circuit 2 to be primed and any air pockets to be purged while minimizing the amount of coating product used for priming. Indeed, this alternative requires less coating product to perform degassing than the filtration circuit priming substep. filtration 2 described previously. In the first pressurization operation of the printing system 10, the valves are then operated so that the supply-filter isolation valve V12 and the filter-printhead isolation valve V23 are open, and the supply purge valve V1, the filter purge valve V3, the filter flush valve V2, the printhead purge valve V5, the printhead flush valve V4, and the purge-fill isolation valve V43 are closed. Therefore, the first conduit C1, the sixth conduit C6, the fifth conduit C5, the ninth conduit C9, the supply-filter isolation valve V12, the single filter F1 and the filter-printhead isolation valve V23 can be filled with coating product. The filtration circuit 2 is then connected to the supply circuit | and to the printhead circuit 3, but not to the filling purge circuit 4. In this operating mode, the printhead A1 is kept isolated from the other circuits by the closure of the print purge valve V5 and the closure of the nozzles A2. The printing system 10 can then be supplied with coating material to pressurize the pipes and fed components, since the flow of the coating material is blocked in the printhead circuit 3. The flow of the coating material occurs in the normal flow direction, from the inlet supply P1 up to the purge-fill isolation valve V43. Pressurization of the printing system 10 is achieved by increasing the pressure of the coating product which arrives through the supply inlet PI. The advantage of this pressurization operation of printing system 10 is that the coating product conveyed from the supply inlet P1 pushes the air pockets contained in the sixth duct C6, the single filter, and the fifth duct CS towards the ninth duct C9. Advantageously, as the pressure in the ducts and the single filter increases with the increase in coating product pressure conveyed in printing system 10, the displaced air bubbles are retained in the ninth duct C9. In the second purging operation of the ninth line C9, the purge-fill isolation valve V43 is opened and the coating material supply is shut off, for example by closing the supply-filter isolation valve V12 or the filter-printhead isolation valve V23 (or another upstream valve not shown). The configuration of the other valves remains unchanged from the first pressurization operation of the printing system 10. The coating product that was under pressure in the printing system 10, and in particular in the ninth conduit C9, can then flow towards the purge outlet of O4 filling, carrying away the air bubbles. This allows the circulation of the coating product to be blocked at the time of debubbling of the printing system 10 and therefore to reduce the amount of coating product needed to prime the filtration circuit 2. In this alternative, prior to cleaning the single filter F1, it is also possible to pressurize the print head A1, the tenth duct C10, and the eleventh duct C11 by closing the print head purge valve V5, the nozzles A2, and supplying the print head circuit 3 with coating material. This ensures that the air introduced into the filtration circuit 2 (during the cleaning of filter F1) is directed solely to the ninth duct C9 during the pressurization of system 10. During the priming stage of the piloting process, the printing system 10 is then placed in a third operating mode called purging and filling with coating product of the head circuit 3. This is also referred to as priming the head circuit 3. The priming of the head circuit 3 can, moreover, be implemented during a third sub-step of priming the head circuit 3, of the priming stage of the piloting process. This third operating mode of purging and filling with re-coat product of the head circuit 3 is illustrated in [Fig.4]. The objective of this third mode of operation is, firstly, to purge any residues of coating or rinsing products from a previous application, of undesirable particles, and to purge the air contained in the ducts and the various elements of the head circuit 3, then, secondly, to fill the ducts, the valves and the print head Al of the head circuit 3 with coating product. In the head circuit priming substep 3, the valves of system 10 are then actuated so that the supply-filter isolation valve V12, the filter-printhead isolation valve V23 and the printhead purge valve VS are open, and the purge-fill isolation valve V43, the supply purge valve V1, the filter purge valve V3, the filter flush valve V2 and the printhead flush valve V4 are closed. The head circuit 3 is thus connected to the supply circuit | and to the filtration circuit 2. In this operating mode, the filling purge circuit 4 is kept isolated from the rest of the circuits. The printing system 10 can then be supplied with coating product to perform the purge and fill the printhead circuit 3. The circulation of the coating product occurs in the normal flow direction, from the inlet supply P1 up to printhead purge outlet O3. In this third operating mode, the first conduit C1, the sixth conduit C6, the fifth conduit C5, the tenth conduit C10, the eleventh conduit C11, the twelfth conduit C12, the supply-filter isolation valve V12, the single filter F1, the filter-printhead isolation valve V23, the printhead purge valve V5 and the printhead A1 can be filled with re-clothing product. System 10 is then placed in an operating mode such that the printhead circuit 3 is purged of printhead rinse fluid residue and any coating product that needs to be expelled from the printhead circuit 3. This purging is performed by supplying the coating product, which, by circulating from the supply inlet O1 through the supply circuit 2 and the filtration circuit 3 to the printhead circuit 3, expels the unwanted residues through the printhead purge outlet O3. This ensures that only the coating product is present in the printhead circuit 3, without impurities that would degrade the quality of the coating product. It also ensures that the filtration circuit is purged of any air bubbles that could degrade print quality. In this operating mode, the coating product flows in the normal direction. Once the various circuits of system 10 have been primed, system 10 is placed in a fourth operating mode, known as the printing mode, which applies the coating product to the object to be coated using the print head A1. The control process thus includes a step of printing the coating product onto the object to be coated in order to place the printing system 10 into the printing mode. This fourth operating mode of printing the coating product is illustrated in [Fig.5]. The objective of this fourth operating mode is to actuate the various valves of system 10 so that the coating material is delivered from the supply inlet P1 to the print head A1, where it is expelled at the nozzles A2 onto the object to be coated. To perform the printing, the valves are actuated to maintain a constant pressure suitable for printing the coating material. In this fourth operating mode, the nozzles A2 are open. During the printing step of the pilot process, the valves of system 10 are then actuated so that the supply-filter isolation valve V12 and the filter-printhead isolation valve V23 are open, and the supply purge valve V1, the filter purge valve V3, the filter rinse valve V2, the printhead rinse valve V4, the purge-fill isolation valve V43 and the printhead purge valve V5 are closed. The supply circuit 1, the filtration circuit 2 and the head circuit 3 are then connected. In this operating mode, the filling purge circuit 4 is kept isolated from the rest of the circuits. The printing system 10 can then be supplied with coating product to perform the printing of the coating product. The circulation of the coating product follows the normal flow direction, from the inlet supply Pl to print head Al where the product is expelled from system 10 by nozzles A2. In this fourth operating mode, the first conduit Cl, the sixth conduit C6, the fifth conduit C5, the tenth conduit C10, the eleventh conduit C11, the supply-filter isolation valve V12, the single filter F1, the filter-printhead isolation valve V23 and the printhead A1 can be filled with coating product. The system 10 is thus placed in an operating mode such that the coating product is conveyed from the supply inlet O1 to the print head Al where it is printed onto the object to be coated. To do this, the coating product flows through the supply circuit 1, then through the filtration circuit 2 where it is filtered of any agglomerates, and finally through the print head circuit 3. In this operating mode, the coating product flows in the normal direction of flow. During the printing of the coating product or before changing the coating product, it may be necessary to rinse the single filter F1. This is the case, for example, if the F1 filter is clogged with agglomerates that prevent the coating product from circulating properly and thus reduce the coating pressure in the print head A1, thereby decreasing print performance. It may also be necessary if a coating product change is required to apply a different coating product. To rinse the single filter F1, the system 10 is placed in a fifth operating mode called the filtration circuit 2 rinsing mode. The control process thus includes a step of rinsing the single filter F1 in order to place the printing system 10 in the filtration circuit 2 rinsing mode. This fifth operating mode for rinsing the filtration circuit 2 is illustrated in [Fig.6]. The objective of this fifth operating mode is to actuate the various valves of system 10 so that the filtration circuit 2 is isolated from the other circuits. The advantage is being able to circulate the filter rinsing fluid from the filter rinsing inlet P2 to the filtration purge outlet O2 in order to rinse the single filter F1. The filter rinsing fluid can then flow in the opposite direction to the normal flow direction in the filtration circuit 2. This opposite flow direction is the optimal direction to rinse the single F1 filter and evacuate the agglomerates retained in its mesh towards the O2 filtration purge outlet. During the rinsing step of the single filter F1, the valves of system 10 are then operated so that the filter rinsing valve V2 and the filter purge valve V3 are open, and the filter-print head isolation valve V23 and the supply-filter isolation valve V12 are closed. Filtration circuit 2 is then isolated from the rest of the circuits. The printing system 10 can then be supplied with filter rinsing fluid in the filtration circuit 2 to perform the rinsing of the single filter F1. In this fifth operating mode, the fourth conduit C4, the fifth conduit CS, the sixth conduit C6, the seventh conduit C7, the filter F1, the filter flushing valve V2 and the filter purge valve V3 are filled with filter flushing fluid. System 10 is thus placed in an operating mode such that the single filter F1 is rinsed in isolation and independently, without interaction with the other circuits of the printing system 10. Specifically, the single filter F1 is rinsed without also having to rinse the print head A1 and / or the supply circuit 1. The single filter F1 is also rinsed only in the opposite direction to the normal flow direction, which allows for a short rinsing time compatible with the productivity requirements of printing coated objects. The filter F1 can then be rinsed with a suitable rinsing fluid. This can be a mixture of solvent and water pulsed with air at a predefined pressure to ensure proper delamination and removal of all agglomerates. The pressure of the filter rinsing fluid is advantageously higher than the pressure of the print head rinsing fluid.For example, it is between 1 bar and 20 bar, preferably between 4 bar and 8 bar. Preferably, the filter rinsing is carried out using an alternative filter rinsing sequence comprising a rinsing operation of the single filter F1 with a filter rinsing liquid, for example, a solvent, followed by a filter purging operation with air, for example, forced air. In such a case, the filter rinsing liquid and the forced air are routed through the filtration circuit 2 from the filter rinsing inlet P2 to the filtration purging outlet O2. This alternative sequence allows for better unclogging and / or rinsing of the single filter F1 of the re-clothing product than rinsing with a liquid alone. The alternative filter rinsing sequence may be repeated one or more times to ensure complete rinsing of the filtration circuit 2, and in particular that the single filter F1 is thoroughly unclogged and / or rinsed of all coating products. Preferably, the air used during this alternative filter rinsing sequence will be expelled from the printing system 10 when the printing system 10 is in the operating mode of purging and filling with coating product of the filtration circuit 2 described in relation to [Fig.3]. Regardless of rinsing the filtration circuit 2, it may be necessary to rinse the printhead circuit 3. For example, to clean the printhead of a previously applied coating. In this case, system 10 is placed in a sixth operating mode called the head circuit rinsing mode 3. The control process then includes a step of rinsing the print head A1 in order to place system 10 in the print head rinsing mode A1. This sixth operating mode for flushing the head circuit 3 is illustrated in [Fig.7]. The objective of this sixth operating mode is to actuate the various valves of system 10 so that the printhead circuit 3 is isolated from the other circuits. The benefit is to allow the filter head rinsing fluid to circulate from the filter head rinsing inlet P3 to the print head purge outlet O3 in order to rinse the print head A1. The filter head rinsing fluid can then flow in the normal direction of flow within the filtration circuit 2. During the A1 printhead rinsing step, the valves of system 10 are actuated so that the printhead purge valve VS and the printhead rinse valve V4 are open, and the filter-printhead isolation valve V23 and the purge-fill isolation valve V43 are closed. It is also possible to actuate the A1 printhead to clean the A2 nozzles of the A1 printhead. In this case, the printhead purge valve V5 can be opened or closed. Preferably, the printhead purge valve V5 is closed to redirect all the pressure of the rinsing fluid to the A2 nozzles. This makes rinsing the A2 nozzles more efficient. The head circuit 3 is then isolated from the rest of the circuits. The printing system 10 can then be supplied with printhead flushing fluid in the printhead circuit 3 to perform printhead flushing. In this sixth operating mode, the eighth conduit C8, the ninth conduit C9, the tenth conduit C10, the eleventh conduit C11, the twelfth conduit C12, the printhead Al, the printhead purge valve VS and the printhead flush valve V4 are filled with printhead flush fluid. Thanks to this sixth operating mode, the print head is rinsed in isolation and independently, without interaction with the other circuits of system 10. In particular, print head A1 is rinsed without also having to rinse the single filter F1 and / or the supply circuit 1. Print head A2 is also The printhead is rinsed only in the normal flow direction, allowing for a short rinsing time compatible with the productivity requirements of printing coated objects. Furthermore, this sixth operating mode can include opening the A2 nozzles to rinse them. The printhead A1 and the A2 nozzles can then be rinsed with the appropriate printhead rinsing fluid, preferably a liquid. This could be, for example, an air-free solvent and water mixture, with a pressure suitable for rinsing the printhead without damaging it and / or the A2 nozzles without damaging them. Preferably, the printhead rinsing fluid is air-free to avoid the risk of drying coating residues in the printhead circuit 3, particularly at the A2 nozzles. The pressure of the printhead rinsing fluid is, for example, between 0.1 bar and 10 bar, preferably between 1 bar and 3 bar. Furthermore, the ninth duct, C9, is a dead zone, meaning it contains only coating material without any flow or air bubbles. The absence of air bubbles in this duct ensures that no air bubbles can be drawn into the tenth duct, C10, during printing. This sixth operating mode ensures that the dead zone of coating material in duct C9, with its stagnant coating material, is properly rinsed. Thanks to the use of independent and isolable circuits, the printing system 10 can be placed simultaneously in the filtration circuit rinsing mode 2 and the printhead circuit rinsing mode 3. This simultaneous operation is a seventh operating mode, known as the combined rinsing mode. This seventh operating mode is illustrated in [Fig. 8]. This seventh combined rinsing mode can be implemented using the piloting method. To do this, the piloting method includes a preliminary step prior to the execution of the printhead rinsing steps A1 and the single filter rinsing steps F1. This preliminary step involves closing the supply-filter isolation valve V12 and the filter-printhead isolation valve V23. Thus, the printhead circuit 3 is isolated from the filtration circuit 2, and the filtration circuit 2 is isolated from both the printhead circuit 3 and the filter circuit. supply 1. Once this first preliminary step has been carried out, it is possible to implement the print head rinsing step Al independently and simultaneously with the rinsing step of the single filter F1. Thus, thanks to the use of independent and isolable circuits, system 10 can be rinsed in less than 20 seconds. Preferably, this time is less than or equal to 15 seconds. Furthermore, thanks to the use of independent and isolable circuits, the printing system 10 can be placed simultaneously in the filtration circuit 2 rinsing mode and the supply circuit 1 priming mode. This simultaneous operating mode is an eighth operating mode, known as simultaneous filtration circuit 2 rinsing and priming. This eighth operating mode is illustrated in [Fig. 9]. This eighth mode can be implemented using the piloting method. To this end, the piloting method includes a second preliminary step prior to the execution of the single filter rinsing step F1 and the priming substep of the supply circuit 1. This second preliminary step includes closing the supply-filter isolation valve V12. Thus, the filtration circuit 2 and the supply circuit 1 are isolated from each other. Furthermore, this second preliminary step can also include closing the filter-printhead isolation valve V23; thus, the filtration circuit 2 is isolated from the printhead circuit 3. Once this second preliminary step has been carried out, it is possible to implement the rinsing step of the single filter F1 independently and simultaneously with the sub-step of priming the supply circuit 1. Thus, thanks to the use of independent and isolable circuits, the single filter F1 can be rinsed in less than 20 seconds while simultaneously priming the coating product supply circuit 1. Preferably, this time is less than or equal to 15 seconds. On the other hand, thanks to the use of independent and isolable circuits, the printing system 10 can be placed simultaneously in the printhead circuit 3 flushing mode and the supply circuit 1 priming mode. This simultaneous operating mode is a ninth operating mode, known as simultaneous printhead circuit 3 flushing and priming. This ninth operating mode is illustrated in [Fig. 10]. This ninth mode can be implemented using the piloting method. To this end, the piloting method includes a third preliminary step prior to the execution of the printhead rinsing step A1 and the priming substep of the supply circuit 1. This second preliminary step includes closing the filter-printhead isolation valve V23. Thus, the printhead circuit 3 and the filtration circuit 2 are isolated from each other. Furthermore, this second preliminary step can also include closing the supply-filter isolation valve V12; thus, the supply circuit is isolated from the filtration circuit 2. Once this second preliminary step has been carried out, it is possible to implement the print head rinsing step Al independently and simultaneously with the sub-step of priming the supply circuit 1. Thus, thanks to the use of independent and isolable circuits, the print head A1 can be rinsed in less than 20 seconds while simultaneously priming the coating supply circuit 1. Preferably, this time is less than or equal to 15 seconds. Finally, thanks to the use of independent and isolable circuits, the printing system 10 can be placed simultaneously in the filtration circuit rinsing mode 2, the printhead circuit rinsing mode 3, and the supply circuit priming mode 1. This simultaneous operating mode is a tenth operating mode, known as simultaneous filtration and printing circuit rinsing and priming. This tenth operating mode is illustrated in [Fig. 11]. This tenth mode can be implemented using the piloting method. To do this, a fourth preliminary step of the piloting method can be implemented to close the supply-filter isolation valve V12 and the filter-printhead isolation valve V23. This isolates the supply circuit 1, the filtration circuit 2, and the printhead circuit 3 from each other. Once this fourth preliminary step has been carried out, it is possible to implement the single filter F1 rinsing step, the print head A1 rinsing step and the supply circuit 1 priming substep independently and simultaneously with each other. Thus, thanks to the use of independent and isolable circuits, the single filter F1 and the print head A1 can be rinsed in less than 20 seconds while simultaneously priming the coating supply circuit 1. Preferably, this time is less than or equal to 15 seconds. In one embodiment, the supply-filter isolation valve V12 and the filter purge valve V3 are combined into a single three-way valve. That is, instead of having two separate valves, the system 10 has a single three-way valve that performs both the roles, defined above, of the supply-filter isolation valve V12 and the filter purge valve V3. In an embodiment compatible with the previous embodiment, the filter-printhead isolation valve V23 and the filter flush valve V2 are assembled into a single three-way valve. That is to say, instead of having two separate valves, the system 10 has a single three-way valve which fulfills both the roles, defined above, of the supply-filter isolation valve V12 and the filter purge valve V3. In an embodiment compatible with previous embodiments, the purge-fill isolation valve V43 and the printhead flush valve V4 are combined into a single three-way valve. That is, instead of having two separate valves, system 10 has a single three-way valve that fills both the roles, defined above, of the purge-fill isolation valve V43 and the print head flushing valve V4. In an embodiment compatible with the preceding embodiments, the operation of the system 10 is ensured by monitoring via monitoring sensors. These sensors measure indicators representative of the system's operating status. For example, a pressure sensor at the print head or between the print head purge valve and the print head monitors that the coating material is correctly conveyed to the print head A1 and that the printing process, by expelling the coating material through the nozzles A2, is correctly carried out. In an embodiment compatible with the preceding embodiments, one or more cameras may be integrated into the system 10 to monitor the operation of the system 10 and detect malfunctions. These may be optical or thermal cameras. If an anomaly is detected by the monitoring sensors, instructions contained in the electronic board or the PLC determine the action to be taken to correct these anomalies. For example, if a sensor detects that filter F1 is clogged with too many agglomerates, the electronic board or the PLC will automatically execute instructions to place system 10 in the filtration circuit 2 rinsing mode, as described previously. Filter F1 can then be rinsed, and the agglomerates can be discharged from system 10 via the filtration purge outlet O2. Afterward, the electronic board or the PLC will execute instructions to return system 10 to the garment printing mode. Such instructions also exist for placing the 1O system into different operating modes. Furthermore, additional instructions can be implemented for practical reasons or depending on the ongoing printing activity. For example, these instructions can be used to implement additional control functions. Furthermore, in an embodiment compatible with the preceding embodiments, the instructions for placing the system 10 into an operating mode are executed according to control instructions. Control instructions are rules defined manually or automatically to indicate how the electronic board or the PLC should supervise and operate the printing system 10. For example, these may be rules concerning the order in which instructions are executed to sequentially place the system 10 into different operating modes successively. In addition, the rules may define a Planning the execution of instructions to place the system 10 in a specific operating mode at a predefined time. This is the case, for example, when planning a printing application within the context of a mass production of a large number of objects to be coated. In an embodiment compatible with the preceding embodiments, the supply circuit 1, the filtration circuit 2, and the head circuit 3 can be rinsed and / or purged using a rinsing and / or purging agent from the purge outlets of system 10. For this purpose, a purge filtration device is installed outside the purge outlets of system 10 to filter the various rinsing and / or purging agents. This embodiment allows the supply circuit 1, the head circuit 3, and the filling purge circuit 4 to be rinsed and / or purged in the opposite direction to the normal flow direction. This embodiment also allows the filtration circuit 2 to be rinsed in the normal flow direction. Thus, this embodiment allows the various elements and conduits of system 10 to be rinsed in both directions. In particular, in such an embodiment, the supply circuit | can be flushed in the opposite direction to the normal flow direction, by a dedicated flushing fluid, from the supply purge outlet O1 or from the filtration purge outlet O2 to the supply inlet P1. In the event that the supply circuit 1 is flushed from the supply purge outlet O1, the supply purge valve V1 is controlled to be open and the supply-filter isolation valve V12 is controlled to be closed. In the event that the supply circuit is flushed from the O2 filtration purge outlet, the supply purge valve V1, the filter-print head isolation valve V23 and the filter flush valve V2 are piloted to be closed, while the supply-filter isolation valve V12, the filter purge valve V3 are piloted to be open. Alternatively, the supply circuit 1 can be flushed with the filter flushing product in the opposite direction to the normal flow direction, from the filter flushing inlet P2 to the supply inlet P1. In such a case, the filter flushing valve V2 and the supply-filter isolation valve V12 are piloted to be open, while the purge valve supply V1, filter-printhead isolation valve V23 and filter purge valve V3 are controlled to be closed.

Claims

Demands

1. A printing system (10) for applying a garment coating product to an object to be coated, the printing system (10) comprising: a print head (A1) to apply the re- product garment on the object to be covered, the coating product flowing in a direction known as the normal flow direction; a single filter (F1) placed upstream of the print head to filter the coating product; a plurality of valves and conduits adapted to convey the coating product and / or a filter rinsing fluid and / or a printhead flushing fluid, said plurality of valves and conduits arranged to form: a supply circuit (1) for re- product garment ; a filtration circuit (2) adapted to convey the coating product through the single filter (F1) in the normal flow direction and to convey the filter flushing fluid through the single filter (F1) only in the opposite direction to the flow direction normal ; a head circuit (3) adapted to carry the product coating and head rinse product printing through the print head (A1) in the normal flow direction; a supply-filter isolation valve (V12) Configured for: in a closed state, isolate the circuit supply (1) of the filtration circuit (2); in an open state, connect the circuit supply (1) to the filtration circuit (2): a configured filter-to-printhead isolation valve (V23) For: in a closed state, isolate the filtration circuit (2) from the head circuit (3); in an open state, connect the filtration circuit (2) to head circuit (3); system in which the filtration circuit (2) further comprises a filter flushing valve (V2) arranged opposite the valve filter-printhead isolation (V23) and a filter purge valve (V3) positioned opposite the supply isolation valve filter (V12), and in which the supply-filter isolation valve (V12), the printhead filter isolation valve (V23), the flushing valve filter (V2) and filter purge valve (V3) are two valves Lanes.

2. A printing system (10) according to claim 1, wherein: the supply-filter isolation valve (V12), the valve filter-printhead isolation (V23), the flushing valve filter (V2) and filter purge valve (V3) include each one has a seat and a spike designed to provide support against the seat; the needle valve of the filter flushing valve (V2) and the needle valve of the filter-printhead isolation valve (V23) are aligned and pointing in opposite directions towards a first common section of conduit; the needle valve of the filter purge valve (V3) and the needle valve of the supply-filter isolation valve (V12) are aligned and pointing in opposite directions towards a second common section of conduit.

3. Printing system (10) according to claim 2, wherein: the first section of common conduit separates the seat from the filter flushing valve (V2) and valve seat filter-printhead isolation (V23) and features a length between 1 mm and 10 mm; the second section of common conduit separates the seat of the filter purge valve (V3) and isolation valve seat supply-filter (V12) and has a length between 1 mm and 10 mm.

4. Printing system (10) according to any one of claims 1 to 3, wherein the filtration circuit (2) further comprises an inlet filter rinsing (P2), the filter rinsing inlet (P2) being adapted to supply the filtration circuit (2) with rinsing product filter, and in which the filter flushing valve (V2) is configured For: in an open state, connect the single filter (F1) to the input of filter rinsing (P2); in a closed state, isolate the single filter (F1) from the input of filter rinsing (P2).

5. Printing system (10) according to any one of claims 1 to 4, in which the filtration circuit (2) further comprises an outlet filtration purge (O2), the filtration purge (O2) outlet being suitable for purging the filtration circuit (2) with a rinsing product filter, the filter purge valve (V3) being configured for: in an open state, connect the single filter (F1) and the output of filtration purge (O2); in a closed state, isolate the single filter (F1) from the output of filtration purge (O2).

6. Printing system (10) according to any one of claims 1 to 5, in which the supply circuit (1) includes an input supply (P1), a supply purge valve (V1) and a supply purge outlet (O1), the inlet supply system adapted to supply the circuit supply (1) of coating product, the purge outlet supply (O1) being adapted to purge the circuit supply (1) of coating product, the purge valve supply (V1) being configured for: in an open state, connect the supply input (P1) and the supply purge outlet (O1); in a closed state, isolate the supply input (P1) from the supply purge outlet (O1).

7. Printing system (10) according to any one of claims 1 to 6, further comprising a filling purge circuit (4) and a purge-fill isolation valve (V43), the isolation valve of purge-refill (V43) being configured for: in an open state, connect the head circuit (3) to the circuit of filling purge (4); in a closed state, isolate the head circuit (3) from the circuit of filling purge (4).

8. Printing system (10) according to claim 7, wherein the head circuit (3) further includes a head flushing valve printing (V4) arranged opposite the isolation valve of purge-fill (V43) and in which the head flushing valve printing (V4) and the purge-fill isolation valve (V43) are two-way valves.

9. Printing system (10) according to any one of claims 1 to 8, in which the head circuit (3) further comprises a valve print head purge (V5) and a print head purge output printing (O3), the print head purge sort (O3) being suitable for purging the head circuit (3) with head flushing product printing and coating product, the head purge valve printing (V5) being configured for: In an open state, connect the print head (A1) and the output print head purging (03); in a closed state, isolate the print head from the output of print head purge (03).

10. Printing system (10) according to any one of claims 1 at 9, characterized in that the single filter (F1) comprises a first one end and a second end, the single filter (F1) being arranged so that the coating product is conveyed along the axis of the filter by entering through the first end of the filter and exiting through the second end, and the rinsing fluid is conveyed along the axis of the filter in entering through the second end of the filter and exiting through the first end.

11. | Method for controlling the printing system (10) according to one any of the claims | at 10, the piloting method comprising one or more of the following steps: Priming in coating product of at least part of the printing system (10); Imprinting of the coating product onto the object to be coated; Print head rinsing (A1); Rinsing the single filter (F1).

12. A piloting method according to claim 11, wherein the steps of print head rinsing (A1) and single filter rinsing (F1) are implemented simultaneously by closing the valve isolation supply-filter (V12) and isolation valve printhead filter (V23).

13. A piloting method according to claim 12, wherein the pressure of the filter flushing fluid is strictly greater than the pressure of the head flushing fluid.

14. A piloting method according to any one of claims 11 to 13, including a step to initiate the supply chain (1) cn coating product ct in which the steps dc rinsing of the single filter (F1) and priming of the supply circuit (1) are put implemented simultaneously by closing the supply isolation valve sion-filter (V12).

15. A piloting method according to any one of claims 11 to 14, including a step to initiate the supply chain (1) in coating product and in which the head rinsing steps printing (A1) and priming of the supply circuit (1) are implemented simultaneously by closing the valve filter-print head isolation (V23).