Computer-implemented method for cleaning self-cleaning head

Abstract

A computer-implemented method for cleaning a self-cleaning marking head of an industrial printer is provided, the method including receiving, by the industrial printer, a control signal from an external controller, and performing, by the industrial printer, a self-cleaning operation of the self-cleaning marking head in response to receiving the control signal.

Description

Technical Field

[0001] The present disclosure relates to a method of externally triggering maintenance of a self-cleaning marking head. Background Art

[0002] Industrial printers, such as continuous inkjet printers, are often used on production lines where products traveling along the line are marked as they pass through the continuous inkjet printer. To maintain the operation of such printers, the continuous inkjet printers need to be maintained. For example, a continuous inkjet printer requires that some of its components, such as its deflection plates or gussets, need to be cleaned to prevent the accumulation of material that could affect print quality. However, to clean a continuous inkjet printer while it is operating on a production line, the line needs to be stopped and the printer's print head moved to a cleaning position. The cleaning position may be a location where an external cleaning device can access the print head. Alternatively, the entire print head may need to be removed from the continuous inkjet printer and sent to a cleaning station for cleaning.

[0003] There is a need to provide alternative methods and apparatus that overcome one or more of the shortcomings of known systems, whether noted in this document or otherwise. Summary of the Invention

[0004] In a first aspect, a computer-implemented method for cleaning a self-cleaning marking head of an industrial printer is provided, the method comprising receiving, by the industrial printer, a control signal from an external controller, and performing, by the industrial printer, a self-cleaning operation of the self-cleaning marking head in response to receiving the control signal.

[0005] Advantageously, the method enables the cleaning operation to be performed with minimal interference with the printing operation. The printing operation may be an operation such as marking an object or product on a production line. The external controller is external to the industrial printer. For example, the external controller may be a production line controller (e.g., a filler, a weigher, a cutter, or any other production equipment operating on the production line). The external controller may have an overview of the operation of the production line and may therefore select an appropriate time to perform cleaning, such as when the production line is stopped. That is, the external controller may allow the cleaning to be coordinated with production line downtime by sending control signals only at appropriate times. The control signal may take any suitable form that is configured such that receipt of the control signal by the industrial printer causes the industrial printer to perform a self-cleaning operation.

[0006] The industrial printer performing the self-cleaning operation of the self-cleaning marking head in response to receiving the control signal may include a processor of the industrial printer performing the self-cleaning operation of the self-cleaning marking head in response to receiving the control signal. In other words, an internal controller or processor within the industrial printer may cause the industrial printer to perform the self-cleaning operation of the self-cleaning marking head upon receiving the control signal.

[0007] Alternatively, the industrial printer (e.g., a processor or internal controller of the industrial printer) can determine that a maintenance issue exists, or that a condition has been met, for example, by using one or more sensors of the industrial printer, and in response, send a message to the external controller to alert the external controller of the maintenance issue. The external controller can then determine an appropriate time to send a control signal to the industrial printer to initiate cleaning.

[0008] The condition may be an expected time. For example, the expected time may be a predetermined time known to an industrial printer by which the printer should perform a self-cleaning operation of the marking head.

[0009] A condition can be determining that no products have passed through the industrial printer within a predetermined time period. For example, the industrial printer may have sensors (or access to data from external sensors) that detect the passage of products as they travel along a conveyor belt. If no products have passed through the industrial printer within the predetermined time period, the production line can be assumed to be idle, and the self-cleaning operation of the self-cleaning marking head can be performed without stopping the line. Sensor data can be combined with time data. For example, a condition can be both determining that no products have passed through the industrial printer within a predetermined time period and determining that the current time corresponds to the aforementioned estimated time.

[0010] The condition may include historical data. For example, the historical data may include the time and / or number of prints that have passed since the last fault event. For example, if it is determined that the time and / or number of prints that have passed since the last fault event has passed, the industrial printer may determine that the condition has been met.

[0011] The historical data may include data indicating the mean time between failures. For example, if it is determined that the industrial printer is approaching or has reached the mean time before failure, the industrial printer may determine that a condition has been met.

[0012] The historical data may include data indicating usage of marking media (eg, ink).For example, if a predetermined amount of marking media has been used, the industrial printer may determine that a condition has been met.

[0013] The historical data may include data indicating the number of markings and / or individual marking actions applied to the product (e.g., the number of drops printed in the case of a continuous inkjet printer). For example, if a predetermined number of markings have been applied, or a predetermined number of individual marking actions have occurred, the industrial printer may determine that a condition has been met.

[0014] The historical data may include data indicating historical environmental data, such as ambient humidity, temperature, and / or pressure, of the environment in which the industrial printer is currently operating. The environmental data may be collected over a predetermined period of time in which the industrial printer has been operating. If the environmental data satisfies a predetermined condition, such as one or more of humidity, temperature, and / or pressure being above (or below) a specific level for a specific period of time, the industrial printer may determine that the condition has been met.

[0015] By providing a self-cleaning operation, disruption to the printing operation is further reduced as there is no need to move the marking head into a specific position to allow access to an external cleaning device.

[0016] The industrial printer and the external controller may include one or more processors configured to perform the steps of the methods disclosed herein. The industrial printer and the external controller may also include a computer-readable memory configured to store non-transitory computer-readable instructions that, when executed by the one or more processors, cause the printer to perform the methods disclosed herein. The industrial printer may be coupled to the external controller such that data can be exchanged between the industrial printer and the external controller. This coupling may include a wired or wireless connection using any suitable protocol that facilitates data exchange.

[0017] Industrial printers are printers used in industrial environments. For example, industrial printers are often used on production lines to mark products as they travel along the line. Industrial printers can be non-contact printers. Industrial printers can be continuous inkjet printers, drop-on-demand inkjet printers, or laser printers.

[0018] The marking head is configured to apply a marking to a product using a marking medium. The marking head may be a print head or a laser. In the case of a continuous inkjet printer, the marking medium may include ink, or in the case of a laser, the marking medium may include photons.

[0019] Self-cleaning operations may include intrinsic cleaning operations.

[0020] An intrinsic cleaning operation is a cleaning operation that does not require the use of an external cleaning device. That is, the self-cleaning marking head is cleaned in situ and does not need to be moved from its normal printing position (e.g., the normal position in which the marking head would be when applying markings to a product) to a cleaning position (e.g., where an external cleaning device is located, or where an external cleaning device is allowed to access the marking head for cleaning). For example, the self-cleaning marking head is not required to be moved away from the surface of the substrate (e.g., the surface of the product) on which the self-cleaning marking head is applying markings in order to allow the external cleaning device to access and clean the space of the self-cleaning marking head. Instead, the self-cleaning marking head can remain in place while it performs its self-cleaning operation.

[0021] The self-cleaning operation may not include the use of external cleaning devices.

[0022] An external cleaning device is a device that is separate from the self-cleaning marking head and / or industrial printer. The external cleaning device may be a device that requires the marking head to be moved from its normal printing position to a cleaning position in order to perform cleaning as described above. For example, the external cleaning device may require access to the marking head that would otherwise be inaccessible if the marking head were in its normal printing position.

[0023] The industrial printer may be a continuous inkjet printer and the self-cleaning marking head may be a self-cleaning print head.

[0024] The self-cleaning operation can be performed by the processor of the industrial printer, which is separate from the external controller. That is, the control logic for driving the various components of the industrial printer described below to perform the self-cleaning operation can be executed by the processor of the industrial printer.

[0025] The self-cleaning operation may include actuating a sealing mechanism of the self-cleaning printhead from a first configuration in which a chamber of the self-cleaning printhead is in communication with atmosphere via at least the ink orifice to a second configuration in which the chamber is sealed.

[0026] The seal is intended to encompass a chamber in fluid communication with one or more conduits, preferably multiple conduits. At least one conduit can be used to supply cleaning fluid to the chamber. At least one conduit can be used to drain used, spent, or dirty cleaning fluid from the chamber. Each of the conduits is preferably closable by a corresponding valve. Each of the conduits is preferably bidirectional, meaning that the conduit can either supply cleaning fluid or drain spent cleaning fluid, depending on the configuration.

[0027] Advantageously, the chamber and any components arranged in the chamber (eg deflection electrodes) are sealed and can be cleaned in an automated manner.

[0028] The chamber may include one or more ports. A port can be considered an opening in the surface of the chamber. One or more of the ports can be coupled to one or more of the conduits.

[0029] The self-cleaning print head may include a nozzle for generating and ejecting a flow of ink drops for printing, at least one electrode for guiding the flow of ink drops, and a slot for receiving ink drops not used for printing. The at least one electrode may be disposed in a chamber.

[0030] The ink orifice can form part of an ink channel, such as an ink slot. During operation, deflected ink is ejected from the printhead through the ink orifice onto a substrate (e.g., an external substrate, such as the surface of a product to be marked). That is, once ink is ejected from the printhead nozzle, it then travels through the ink orifice to exit the chamber and land on the substrate. In a first configuration, the ink orifice is open, allowing ink to flow out of the chamber. In a second configuration, the ink orifice is closed, preventing ink from flowing out of the chamber; for example, the chamber is sealed from the external atmosphere.

[0031] The self-cleaning operation may also include directing a cleaning fluid into the chamber to clean the chamber.

[0032] The chamber may be referred to as a cleaning chamber. The cleaning fluid may be a solvent. The cleaning fluid may be a mixture of solvents.

[0033] Directing the cleaning fluid into the chamber may include pumping the cleaning fluid into the chamber (eg, under positive pressure).

[0034] Guiding the cleaning fluid into the chamber can include sucking (e.g., extracting) the cleaning fluid into the chamber under negative pressure. The cleaning fluid can then be extracted from the chamber again under negative pressure. Advantageously, a tank pump can be used to extract the cleaning fluid in this way. Extracting the cleaning fluid under negative pressure is advantageously fail-safe because if the sealing mechanism fails, the cleaning fluid will not be extracted into the chamber due to the negative pressure of only extracting air via the opened sealing mechanism. Therefore, this arrangement is inherently fail-safe in alleviating the risk of pressurized cleaning fluid being accidentally ejected from the print head onto the print line (e.g., products on a production line).

[0035] The method can also include discharging the used cleaning fluid from the chamber. When (new / fresh) cleaning fluid is pumped into the chamber, the used cleaning fluid can be discharged simultaneously. That is to say, the cleaning fluid can be actively pumped or extracted through the chamber. Alternatively, the cleaning fluid can occupy the chamber for a period of time (e.g., a residence time or a dwell period, e.g., about 5 seconds) before being subsequently discharged. That is to say, the cleaning fluid can reside in the chamber for a period of time in a stagnant manner. Therefore, the cleaning fluid can stay for a period of time in the cleaning chamber. The cleaning fluid discharged from the chamber can be stored in a separate fluid reservoir (e.g., separated from a mixing box). A separate fluid reservoir can selectively be connected to a mixing box to maintain viscosity.

[0036] Cleaning fluid can be directed into the chamber from a solvent reservoir (e.g., a solvent tank). The solvent reservoir can contain solvent that has been previously used in the ink system. Cleaning fluid can be directed into the chamber from a solvent cartridge. The solvent cartridge can contain fresh or unused solvent. A cleaning cycle can first be performed using cleaning fluid from the solvent reservoir. A cleaning cycle can then be performed using fresh cleaning fluid from the solvent cartridge. This can be described as pre-cleaning with dirty solvent and completing the cleaning cycle by flushing with unused solvent. Cleaning the chamber can include agitating the cleaning fluid in the chamber by directing a flow of air through the chamber. This can be described as bubbling air through the chamber to agitate the cleaning fluid in the chamber.

[0037] If the chamber is in fluid communication with multiple conduits, the conduits are preferably connected to the chamber at different locations. For example, a first conduit may be connected to the upstream end of the chamber (e.g., near the nozzle). For example, a second conduit may be connected to the downstream end of the chamber (e.g., near the tank). The ports connected to the conduits are preferably located at diametrically opposed locations within the chamber. For example, a first port may be located in a first corner of a cubic chamber, and a second port may be located in a diagonally opposite second corner of the cubic chamber.

[0038] The sealing mechanism may include a rotatable body that is rotatable about a rotation axis between a first configuration and a second configuration, and wherein driving the sealing mechanism of the self-cleaning print head from the first configuration to the second configuration includes rotating the rotatable body of the sealing mechanism of the self-cleaning print head from the first configuration to the second configuration, wherein the chamber is sealed by the rotatable body.

[0039] The chamber may include multiple ports, and the method may further include selecting, by the continuous inkjet printer, a port of the chamber as a fill port and a port of the chamber as a drain port based on the orientation of the self-cleaning print head, wherein directing a cleaning fluid into the chamber to clean the chamber includes directing a flow of cleaning fluid through the fill port into the cleaning chamber to clean the cleaning chamber, and draining the cleaning fluid from the cleaning chamber through the drain port to empty the cleaning chamber.

[0040] The method may further include detecting, by the continuous inkjet printer, an orientation of the self-cleaning printhead using an orientation sensor.

[0041] The orientation sensor may be configured to output an orientation signal indicating an orientation of the self-cleaning print head. Upon receiving the orientation signal indicating the orientation of the self-cleaning print head, the continuous inkjet printer may output valve control signals to the plurality of valves to control the flow of cleaning fluid into and / or out of the chamber based on the orientation of the self-cleaning print head, wherein the plurality of valves are operable to control the flow of cleaning fluid into and / or out of the chamber.

[0042] The control signal may be sent based on a predetermined condition being satisfied.

[0043] The predetermined condition may be a state of a production line on which the industrial printer is operating. This state may include a stoppage of the production line on which the industrial printer is operating. For example, if the production line stops due to a malfunction of a component on the production line, a self-cleaning operation may be performed while the production line is stopped, thereby utilizing the unexpected downtime.

[0044] The predetermined conditions may include a predetermined time. For example, a production line may be scheduled to stop at a predetermined time in order to perform maintenance or change the product to be marked. Thus, the predetermined time may be a scheduled maintenance time or a change in product over time.

[0045] The method may further include sending, by the external controller, a control signal to the industrial printer.

[0046] As described above, the external controller may send a control signal when it determines that a predetermined condition has been met. For example, the external controller may determine that production on a production line has been stopped due to an unplanned event (such as a failure of a component other than the industrial printer). In this manner, the marking head can be cleaned while the production line is down, without unnecessarily stopping the line to clean the marking head.

[0047] The computer-implemented method may also include determining, by the industrial printer, completion of the self-cleaning operation, and sending, by the industrial printer, data indicating completion of the self-cleaning operation to the external controller.

[0048] In this way, the external controller is kept informed of the status of the industrial inkjet printer.

[0049] In a second aspect, a computer-implemented method for cleaning a self-cleaning marking head of an industrial printer is provided, the method comprising: obtaining, by the industrial printer, sensor data indicating operation of the self-cleaning marking head, determining, by the industrial printer, a maintenance issue associated with the self-cleaning marking head based on the sensor data, and performing, by the industrial printer, a self-cleaning operation of the self-cleaning marking head in response to the determined maintenance issue.

[0050] Advantageously, an industrial printer can identify maintenance issues associated with a self-cleaning marking head that could potentially impact printing performance and automatically take action to remedy the maintenance issue by initiating a cleaning operation. The maintenance issue could be, for example, the detection of debris buildup in or around the nozzles, slots, or deflector plates of the marking head, or the detection of an EHT trip. Automatically taking action to perform a self-cleaning operation eliminates the need for an operator to manually initiate or perform cleaning.

[0051] The self-cleaning operation may be as described within the present disclosure.The self-cleaning operation may be self-cleaning in that it does not require extrinsic cleaning of the self-cleaning marking head, for example using an external cleaning device.

[0052] The industrial printer may be configured to operate on a production line, applying markings to products on the production line. The determination of a maintenance issue may be determined while the industrial printer is using a self-cleaning marking head to mark products on the production line.

[0053] Sensor data may be acquired from one or more sensors associated with the printer and / or the self-cleaning marking head.

[0054] The industrial printer may be a continuous inkjet printer and the self-cleaning marking head may be a self-cleaning print head.

[0055] The self-cleaning operation may include actuating a sealing mechanism of the self-cleaning printhead from a first configuration in which a chamber of the self-cleaning printhead is in communication with atmosphere via at least the ink orifice to a second configuration in which the chamber is sealed.

[0056] The seal is intended to encompass a chamber in fluid communication with one or more conduits, preferably multiple conduits. At least one conduit can be used to supply cleaning fluid to the chamber. At least one conduit can be used to drain spent / used / dirty cleaning fluid from the chamber. Each of the conduits is preferably closable by a corresponding valve. Each of the conduits is preferably bidirectional, as the conduit can either supply cleaning fluid or drain spent cleaning fluid, depending on the configuration.

[0057] Advantageously, the chamber and any components arranged in the chamber (eg deflection electrodes) are sealed and can be cleaned in an automated manner.

[0058] The chamber may include one or more ports. A port can be considered an opening in the surface of the chamber. One or more of the ports can be coupled to one or more of the conduits.

[0059] The self-cleaning print head may include a nozzle for generating and ejecting a flow of ink drops for printing, at least one electrode for guiding the flow of ink drops, and a slot for receiving ink drops not used for printing. The at least one electrode may be disposed in a chamber.

[0060] The ink orifice can form part of an ink channel, such as an ink slot. During operation, deflected ink is ejected from the printhead through the ink orifice onto a substrate (e.g., an external substrate, such as the surface of a product to be marked). That is, once ink is ejected from the printhead nozzle, it then travels through the ink orifice to exit the chamber and land on the substrate. In a first configuration, the ink orifice is open, allowing ink to flow out of the chamber. In a second configuration, the ink orifice is closed, preventing ink from flowing out of the chamber; for example, the chamber is sealed from the external atmosphere.

[0061] The self-cleaning operation may also include directing a cleaning fluid into the chamber to clean the chamber.

[0062] The chamber may be referred to as a cleaning chamber. The cleaning fluid may be a solvent. The cleaning fluid may be a mixture of solvents.

[0063] Directing the cleaning fluid into the chamber may include pumping the cleaning fluid into the chamber (eg, under positive pressure).

[0064] Guiding the cleaning fluid into the chamber can include sucking (e.g., extracting) the cleaning fluid into the chamber under negative pressure. The cleaning fluid can then be extracted from the chamber again under negative pressure. Advantageously, a tank pump can be used to extract the cleaning fluid in this way. Extracting the cleaning fluid under negative pressure is advantageously fail-safe because if the sealing mechanism fails, the cleaning fluid will not be extracted into the chamber due to the negative pressure of only extracting air via the opened sealing mechanism. Therefore, this arrangement is inherently fail-safe in alleviating the risk of pressurized cleaning fluid being accidentally ejected from the print head onto the print line (e.g., products on a production line).

[0065] The method can also include discharging the cleaning fluid from the chamber. When (new / fresh) cleaning fluid is pumped into the chamber, the used cleaning fluid can be discharged simultaneously. That is to say, the cleaning fluid can be actively pumped or drawn through the chamber. Alternatively, the cleaning fluid can occupy the chamber for a period of time (e.g., a residence time or a dwell period, e.g., about 5 seconds) before being subsequently discharged. That is to say, the cleaning fluid can reside in the chamber for a period of time in a stagnant manner. Therefore, the cleaning fluid can stay for a period of time in the cleaning chamber. The cleaning fluid discharged from the chamber can be stored in a separate fluid reservoir (e.g., separated from a mixing box). A separate fluid reservoir can selectively be connected to a mixing box to maintain viscosity.

[0066] Cleaning fluid can be directed into the chamber from a solvent reservoir (e.g., a solvent tank). The solvent reservoir can contain solvent that has been previously used in the ink system. Cleaning fluid can be directed into the chamber from a solvent cartridge. The solvent cartridge can contain fresh or unused solvent. A cleaning cycle can first be performed using cleaning fluid from the solvent reservoir. A cleaning cycle can then be performed using fresh cleaning fluid from the solvent cartridge. This can be described as pre-cleaning with dirty solvent and completing the cleaning cycle by flushing with unused solvent. Cleaning the chamber can include agitating the cleaning fluid in the chamber by directing a flow of air through the chamber. This can be described as bubbling air through the chamber to agitate the cleaning fluid in the chamber.

[0067] If the chamber is in fluid communication with multiple conduits, the conduits are preferably connected to the chamber at different locations. For example, a first conduit may be connected to the upstream end of the chamber (e.g., near the nozzle). For example, a second conduit may be connected to the downstream end of the chamber (e.g., near the tank). The ports connected to the conduits are preferably located at diametrically opposed locations within the chamber. For example, a first port may be located in a first corner of a cubic chamber, and a second port may be located in a diagonally opposite second corner of the cubic chamber.

[0068] The sealing mechanism may include a rotatable body that is rotatable about a rotation axis between a first configuration and a second configuration, and wherein driving the sealing mechanism of the self-cleaning print head from the first configuration to the second configuration includes rotating the rotatable body of the sealing mechanism of the self-cleaning print head from the first configuration to the second configuration, wherein the chamber is sealed by the rotatable body.

[0069] The chamber may include multiple ports, and the method may further include selecting, by the continuous inkjet printer, a port of the chamber as a fill port and a port of the chamber as a drain port based on the orientation of the self-cleaning print head, wherein directing a cleaning fluid into the chamber to clean the chamber includes directing a flow of cleaning fluid through the fill port into the cleaning chamber to clean the cleaning chamber, and draining the cleaning fluid from the cleaning chamber through the drain port to empty the cleaning chamber.

[0070] The method may further include detecting, by the continuous inkjet printer, an orientation of the self-cleaning printhead using an orientation sensor.

[0071] The orientation sensor may be configured to output an orientation signal indicating an orientation of the self-cleaning print head. Upon receiving the orientation signal indicating the orientation of the self-cleaning print head, the continuous inkjet printer may output valve control signals to the plurality of valves to control the flow of cleaning fluid into and / or out of the chamber based on the orientation of the self-cleaning print head, wherein the plurality of valves are operable to control the flow of cleaning fluid into and / or out of the chamber.

[0072] The industrial printer may comprise a second marking head, and wherein the second marking head is driven to mark one or more products while the mentioned first self-cleaning marking head is undergoing a self-cleaning operation.

[0073] In this way, while the self-cleaning marking head is being cleaned (and unable to mark products), the second marking head can be used instead. This allows the marking head to be cleaned without having to stop printing. For example, if an industrial printer is operating on a production line, marking products traveling along the line, the self-cleaning marking head can be cleaned without stopping the line because the second marking head can replace the (first) self-cleaning marking head.

[0074] Marking the one or more products using the second marking head may include activating the second marking head to print on the one or more products in place of the first self-cleaning marking head.

[0075] The computer-implemented method may also include determining, by the industrial printer, completion of the self-cleaning operation and, in response, driving the first self-cleaning marking head to print on the one or more products in place of the second marking head.

[0076] That is, once cleaning is complete, the printer can switch back to using the first marking head instead of the second marking head. The second marking head can enter a dormant or standby state when not in use. Of course, the second marking head can be cleaned when not in use, for example, while the first self-cleaning marking head is being used. Of course, the printer can alternatively continue to use the second marking head for printing while the first self-cleaning marking head is in standby mode, and then re-use the first self-cleaning marking head when the second marking head requires cleaning. The detection of the need for cleaning the second marking head can be the same as the detection of the need for cleaning the first self-cleaning marking head.

[0077] The second marking head may be a second self-cleaning marking head.

[0078] When the printer has switched back to using the first self-cleaning marking head instead of the second marking head, the second self-cleaning marking head may be automatically cleaned.

[0079] The computer-implemented method may also include sending, by the industrial printer and in response to the determination of the maintenance problem, data indicating the maintenance problem to an external controller, and receiving, by the industrial printer and from the external controller, a control signal configured to cause the industrial printer to perform a cleaning operation, wherein performing, by the industrial printer, the cleaning operation in response to the maintenance problem includes performing, by the industrial printer, the cleaning operation in response to the control signal.

[0080] The external controller is external to the industrial printer, as described above. For example, the external controller could be a production line controller (e.g., a filling machine). The industrial printer can determine that a maintenance issue exists and, in response, send a message (data indicating the maintenance issue) to the external controller to alert it of the problem. The external controller can then determine the appropriate time to send a control signal to the industrial printer to initiate cleaning. The external controller can have an overview of the production line's operations and therefore select an appropriate time to perform cleaning, such as when the line is stopped. In other words, the external controller can coordinate cleaning with production line downtime.

[0081] The computer-implemented method may further include sending, by the external controller, a control signal to the industrial printer.

[0082] Transmitting the control signal by the external controller may include determining, by the external controller, that a predetermined condition is satisfied, and transmitting the control signal upon determining that the predetermined condition is satisfied.

[0083] The predetermined condition may be a predetermined time, such as a known time of production downtime on a production line.

[0084] The predetermined condition may be the status of a production line on which the industrial printer is operating.

[0085] The state may include a stop on the production line on which the industrial printer is operating.

[0086] For example, an external controller may determine that production on a production line has stopped due to an unplanned event (such as a failure of a component other than the industrial printer.) In this way, cleaning of the marking head can be performed while the production line is down, without having to unnecessarily stop the production line to clean the marking head.

[0087] The predetermined conditions may include a predetermined time. For example, a production line may be scheduled to stop at a predetermined time in order to perform maintenance or change the product to be marked. Thus, the predetermined time may be a scheduled maintenance time or a change in product over time.

[0088] The computer-implemented method may also include determining, by the industrial printer, completion of the self-cleaning operation, and sending, by the industrial printer, data indicating completion of the self-cleaning operation to the external controller.

[0089] For example, the industrial printer may determine that the cleaning operation is complete and alert the external controller by sending a message indicating that the industrial printer is ready to print again (data indicating that the self-cleaning operation is complete). The industrial printer may then receive another control signal from the external controller that causes the industrial printer to mark the product with the first self-cleaning marking head.

[0090] In a third aspect, a computer-implemented method for operating an industrial printer is provided, the industrial printer comprising a first marking head and a second marking head, the industrial printer operating on a production line and marking products on the production line using the first marking head, the computer-implemented method comprising determining a maintenance issue associated with the first marking head, performing a cleaning operation on the first marking head in response to determining the maintenance issue, and driving the second marking head to replace the first marking head to mark products on the production line in response to the performing.

[0091] In this way, while the first marking head is being cleaned (and cannot mark products), the second marking head can be used instead to replace the first marking head. This allows the marking heads to be cleaned without having to stop printing.

[0092] The logic associated with each step can occur at any suitable processor. For example, the determination of a maintenance issue associated with the first marking head can be performed by an external controller or a processor of the industrial printer. The maintenance issue can be determined based on recorded sensor data from one or more sensors associated with the printer and / or the first marking head.

[0093] The first marking head and / or the second marking head may be a self-cleaning marking head, and the cleaning operation may be a self-cleaning operation.

[0094] The self-cleaning operation may be a self-cleaning operation as disclosed herein.

[0095] The industrial printer may be a continuous inkjet printer, and the first self-cleaning marking head and the second self-cleaning marking head may be a first self-cleaning print head and a second self-cleaning print head.

[0096] The self-cleaning operation may include actuating a sealing mechanism of the first self-cleaning printhead from a first configuration in which a chamber of the first self-cleaning printhead communicates with atmosphere via at least the ink orifice to a second configuration in which the chamber is sealed.

[0097] The seal is intended to encompass a chamber in fluid communication with one or more conduits, preferably multiple conduits. At least one conduit can be used to supply cleaning fluid to the chamber. At least one conduit can be used to drain used, spent, or dirty cleaning fluid from the chamber. Each of the conduits is preferably closable by a corresponding valve. Each of the conduits is preferably bidirectional, meaning that the conduit can either supply cleaning fluid or drain spent cleaning fluid, depending on the configuration.

[0098] Advantageously, the chamber and any components arranged in the chamber (eg deflection electrodes) are sealed and can be cleaned in an automated manner.

[0099] The chamber may include one or more ports. A port can be considered an opening in the surface of the chamber. One or more of the ports can be coupled to one or more of the conduits.

[0100] The first self-cleaning print head may include a nozzle for generating and ejecting a flow of ink drops for printing, at least one electrode for guiding the flow of ink drops, and a slot for receiving ink drops not used for printing. The at least one electrode may be disposed in the chamber.

[0101] The ink orifice can form part of an ink channel, such as an ink slot. During operation, deflected ink is ejected from the printhead through the ink orifice onto a substrate (e.g., an external substrate, such as the surface of a product to be marked). That is, once ink is ejected from the printhead nozzle, it then travels through the ink orifice to exit the chamber and land on the substrate. In a first configuration, the ink orifice is open, allowing ink to flow out of the chamber. In a second configuration, the ink orifice is closed, preventing ink from flowing out of the chamber; for example, the chamber is sealed from the external atmosphere.

[0102] The self-cleaning operation may also include directing a cleaning fluid into the chamber to clean the chamber.

[0103] The chamber may be referred to as a cleaning chamber. The cleaning fluid may be a solvent. The cleaning fluid may be a mixture of solvents.

[0104] Directing the cleaning fluid into the chamber may include pumping the cleaning fluid into the chamber (eg, under positive pressure).

[0105] Directing the cleaning fluid into the chamber may include sucking (e.g., extracting) the cleaning fluid into the chamber under negative pressure. The cleaning fluid can then be extracted from the chamber again under negative pressure. Advantageously, a gutter pump can be used to extract the cleaning fluid in this manner. Extracting the cleaning fluid under negative pressure is advantageously fail-safe because if the sealing mechanism fails, the cleaning fluid will not be extracted into the chamber due to the negative pressure of only sucking air through the opened sealing mechanism. Therefore, this arrangement is inherently fail-safe in mitigating the risk of pressurized cleaning fluid being accidentally ejected from the print head onto a print line (e.g., a product on a production line).

[0106] The method may also include discharging the spent cleaning fluid from the chamber. When (new / fresh) cleaning fluid is pumped into the chamber, the spent cleaning fluid may be discharged simultaneously. In other words, the cleaning fluid may be actively pumped or extracted through the chamber. Alternatively, the cleaning fluid may occupy the chamber for a period of time (e.g., a residence time or dwell period, e.g., approximately 5 seconds) before subsequently discharging. In other words, the cleaning fluid may reside in the chamber for a period of time in a stagnant manner. Therefore, the cleaning fluid may stay in the cleaning chamber for a period of time. The cleaning fluid discharged from the chamber may be stored in a separate fluid reservoir (e.g., separate from a mixing tank). The separate fluid reservoir may be selectively connected to the mixing tank to maintain viscosity.

[0107] Cleaning fluid can be directed into the chamber from a solvent reservoir (e.g., a solvent tank). The solvent reservoir can contain solvent that has been previously used in the ink system. Cleaning fluid can be directed into the chamber from a solvent cartridge. The solvent cartridge can contain fresh or unused solvent. A cleaning cycle can first be performed using cleaning fluid from the solvent reservoir. A cleaning cycle can then be performed using fresh cleaning fluid from the solvent cartridge. This can be described as pre-cleaning with dirty solvent and completing the cleaning cycle by flushing with unused solvent. Cleaning the chamber can include agitating the cleaning fluid in the chamber by directing a flow of air through the chamber. This can be described as bubbling air through the chamber to agitate the cleaning fluid in the chamber.

[0108] If the chamber is in fluid communication with multiple conduits, the conduits are preferably connected to the chamber at different locations. For example, a first conduit may be connected to the upstream end of the chamber (e.g., near the nozzle). For example, a second conduit may be connected to the downstream end of the chamber (e.g., near the tank). The ports connected to the conduits are preferably located at diametrically opposed locations within the chamber. For example, a first port may be located in a first corner of a cubic chamber, and a second port may be located in a diagonally opposite second corner of the cubic chamber.

[0109] The sealing mechanism may include a rotatable body that is rotatable about a rotation axis between a first configuration and a second configuration, and wherein driving the sealing mechanism of the self-cleaning print head from the first configuration to the second configuration includes rotating the rotatable body of the sealing mechanism of the self-cleaning print head from the first configuration to the second configuration, wherein the chamber is sealed by the rotatable body.

[0110] The chamber may include multiple ports, and the method may further include selecting, by the continuous inkjet printer, a port of the chamber as a fill port and a port of the chamber as a drain port based on the orientation of the self-cleaning print head, wherein directing a cleaning fluid into the chamber to clean the chamber includes directing a flow of cleaning fluid through the fill port into the cleaning chamber to clean the cleaning chamber, and draining the cleaning fluid from the cleaning chamber through the drain port to empty the cleaning chamber.

[0111] The method may further include detecting, by the continuous inkjet printer, an orientation of the self-cleaning printhead using an orientation sensor.

[0112] The orientation sensor may be configured to output an orientation signal indicating an orientation of the self-cleaning print head. Upon receiving the orientation signal indicating the orientation of the self-cleaning print head, the continuous inkjet printer may output valve control signals to the plurality of valves to control the flow of cleaning fluid into and / or out of the chamber based on the orientation of the self-cleaning print head, wherein the plurality of valves are operable to control the flow of cleaning fluid into and / or out of the chamber.

[0113] When the first marking head is being used to mark products, the second marking head may not be being used to mark products.

[0114] For example, the second marking head may be considered a spare marking head that is not used during normal use, and is only used when the first marking head is being cleaned (or is otherwise inoperative).

[0115] In a fourth aspect, a computer-implemented method for cleaning a self-cleaning marking head of an industrial printer is provided, the method comprising determining, by the industrial printer, that a condition has been met, and, by the industrial printer, in response to determining that the condition has been met, performing a self-cleaning operation of the self-cleaning marking head.

[0116] The condition may be an expected time (or time period). For example, the expected time may be a predetermined time known to an industrial printer, by which the printer should perform a self-cleaning operation of the marking head.

[0117] A condition can be determining that no products have passed through the industrial printer within a predetermined time period. For example, the industrial printer may have sensors (or access to data from external sensors) that detect the passage of products as they travel along a conveyor belt. If no products have passed through the industrial printer within the predetermined time period, the production line can be assumed to be idle, and the self-cleaning operation of the self-cleaning marking head can be performed without stopping the line. Sensor data can be combined with time data. For example, a condition can be both determining that no products have passed through the industrial printer within a predetermined time period and determining that the current time corresponds to the aforementioned estimated time.

[0118] The condition may include historical data. For example, the historical data may include the time and / or number of prints that have passed since the last fault event. For example, if it is determined that the time and / or number of prints that have passed since the last fault event has passed, the industrial printer may determine that the condition has been met.

[0119] The historical data may include data indicating the mean time between failures. For example, if it is determined that the industrial printer is approaching or has reached the mean time before failure, the industrial printer may determine that a condition has been met.

[0120] The historical data may include data indicating usage of marking media (eg, ink).For example, if a predetermined amount of marking media has been used, the industrial printer may determine that a condition has been met.

[0121] The historical data may include data indicating the number of markings and / or individual marking actions applied to the product (e.g., the number of drops printed in the case of a continuous inkjet printer). For example, if a predetermined number of markings have been applied, or a predetermined number of individual marking actions have occurred, the industrial printer may determine that a condition has been met.

[0122] The historical data may include data indicating historical environmental data, such as ambient humidity, temperature, and / or pressure, of the environment in which the industrial printer is currently operating. The environmental data may be collected over a predetermined period of time in which the industrial printer has been operating. If the environmental data satisfies a predetermined condition, such as one or more of humidity, temperature, and / or pressure being above (or below) a specific level for a specific period of time, the industrial printer may determine that the condition has been met.

[0123] The method may further include acquiring, by the industrial printer, sensor data indicative of operation of the self-cleaning marking head, wherein determining, by the industrial printer, that the condition has been met includes determining a maintenance issue associated with the self-cleaning marking head based on the sensor data.

[0124] In a fifth aspect, a system is provided comprising an industrial printer, an external controller coupled to the industrial printer, and wherein the system is configured to perform the methods of the first, second, third and fourth aspects.

[0125] An industrial printer may include one or more processors and a computer-readable medium having computer-readable instructions stored thereon, wherein the computer-readable instructions, when executed by the one or more processors, cause the one or more processors to perform the method according to the first, second, or third aspect disclosed herein. For example, the instructions may cause the one or more processors to receive the aforementioned control signal from an external controller and cause the one or more processors to perform the self-cleaning operation described above.

[0126] The external controller may include one or more processors and a computer-readable medium having computer-readable instructions stored thereon, wherein the computer-readable instructions, when executed by the one or more processors, cause the one or more processors to perform the method according to the first, second, or third aspect disclosed herein. For example, the instructions may cause the one or more processors to send control signals as described with respect to any of the first, second, and third aspects.

[0127] The external controller may be coupled to the industrial printer using any suitable means (wired or wireless) that facilitates data transfer.

[0128] In a sixth aspect, there is provided a computer-readable medium storing computer-readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method of any one of the first, second, third or fourth aspects.

[0129] It will be appreciated that optional features of one aspect may be combined with features of another aspect.It will also be appreciated that where a particular device (such as an industrial printer or external controller) is stated to perform a particular function, that device may use its processor to perform that function. BRIEF DESCRIPTION OF THE DRAWINGS

[0130] Specific embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0131] Figure 1 is a schematic diagram of continuous inkjet (CIJ);

[0132] Figure 2 Is alone Figure 1 a perspective view of a print head of the illustrated printer;

[0133] Figure 3 yes Figure 2 An alternative perspective view of the print head with the outer casing omitted;

[0134] Figure 4 yes Figure 3 An alternative perspective view of a print head;

[0135] Figure 5 yes Figure 4 and Figure 5 an enlarged view of a portion of the printhead shown with the chamber housing omitted;

[0136] Figure 6 yes Figures 2 to 5 a perspective view of a subassembly of a print head;

[0137] Figure 7 yes Figure 6 a cross-sectional side view of a subassembly of;

[0138] Figure 8 yes Figure 6 and Figure 7 Alternative cross-sectional views of subassemblies of;

[0139] Figure 9 is used for Figure 1 Simplified schematic diagram of the fluid system of the printer; combined Figures 2 to 7 The print head shown in ;

[0140] Figure 10 shows a schematic diagram of a production line on which a continuous inkjet printer operates;

[0141] Figure 11 A flow chart illustrating a method for cleaning a self-cleaning print head is shown;

[0142] Figure 12 A flow chart illustrating another method of cleaning a self-cleaning print head; and

[0143] Figure 13 An example computing device is shown upon which the methods disclosed herein may be performed. DETAILED DESCRIPTION

[0144] Figure 1A continuous inkjet (CIJ) printer 1 is schematically shown. The printer 1 includes a printer body 2 (which may be referred to as a cabinet) connected to a printhead 3 via an umbilical cable 4. The printer body 2 houses an ink system 5 and a printer controller 6. The printer body 2 also has an interface 7 (e.g., a display, keypad, and / or touchscreen) for use by an operator.

[0145] The printhead 3 is arranged to print on a substrate disposed adjacent to the printhead 3. The printer 1 typically includes two cartridge connectors for engaging respective fluid cartridges. In particular, the printer 1 includes an ink cartridge connector for engaging an ink cartridge 8 and a (separate) solvent cartridge connector for engaging a solvent cartridge 10. The cartridge connectors typically each include a fluid port that is arranged to connect to a fluid pathway within the printer 1 to allow fluid to flow between the cartridges 8, 10 and other parts of the inkjet printer 1, such as the ink system 5 and the printhead 3 (via the umbilical 4).

[0146] In operation, ink from ink cartridge 8 and solvent from solvent cartridge 10 can be mixed within ink system 5 to produce printing ink of a desired viscosity suitable for printing. This ink is supplied to printhead 3, and unused ink is returned from printhead 3 to ink system 5 (via umbilical cord 4). When unused ink is returned from printhead 3 to ink system 5, air can be drawn in along with ink from the gutter of printhead 3. The air can then become saturated with the solvent in the gutter line.

[0147] In operation, ink is delivered under pressure from the ink system 5 to the printhead 3 and recirculated back into the umbilical cable 4 via flexible tubing, which is bundled with other fluid tubes and electrical wiring (not shown). To maintain the correct consistency of the ink, the ink system 5 is operable to mix ink removed from the cartridge 8 with solvent removed from the cartridge 10 and blend them together to obtain an ink having the correct viscosity and / or density for a particular printing application.

[0148] Of particular relevance to the present application is that the printhead 3 is a self-cleaning printhead. Without operator intervention, the printhead 3 can be sealed and a cleaning fluid can be flushed through at least a portion of the printhead 3 to clean the printhead 3. As will be explained in the following description and accompanying figures, this is achieved by incorporating a sealing mechanism including a rotatable body into the printhead 3.

[0149] Go to Figure 2 , provides a perspective view of a separate print head 3.

[0150] The print head 3 includes a first end 100, through which the print head 3 can be connected to the umbilical cord 4, such as Figure 1As shown. Thus, the first end 100 can include a connector (e.g., a threaded connector in the illustrated embodiment). At the opposite end, the printhead 3 includes a second end 102. An end cap 104 is disposed at the second end 102. The end cap 104 defines the outermost portion of the printhead 3. The end cap 104 includes an ink aperture 106, which can be referred to as an ink slot. In operation, deflected ink is ejected from the printhead 3 through the ink aperture 106 onto a substrate (e.g., an external substrate that moves past the printhead 3). Generally extending between the first end 100 and the second end 102 is a housing 108. In the illustrated embodiment, the housing 108 is generally cylindrical and provides a protective cover for the components that make up the printhead 3. The housing 108 is removable to expose the components, such as for maintenance. The combination of the end cap 104 and the housing 108 can be described as an outer cover 110 of the printhead 3.

[0151] When the print head 3 is to be cleaned (e.g., by the self-cleaning capability of the print head 3), the ink holes 106 can be effectively closed and sealed by a sealing mechanism within the print head 3. That is, when a cleaning fluid is flushed through the chamber of the print head 3 (which will be described below), the cleaning fluid cannot escape from the print head 3 through the ink holes 106. For the purposes of this application, the closing of the ink holes 106 may not infer a change in the geometry of the ink holes 106 themselves. That is, the ink holes 106 remain as Figure 2 As shown, regardless of whether it is open or closed (via operation of the sealing mechanism). However, at least in the illustrated embodiment, the ink hole 106 can be obscured (e.g., covered internally) by the upstream rotatable body to define a sealed chamber. This will be described in detail later in this document.

[0152] Go to Figure 3 , provides a perspective view of the print head 3, in which the housing 108 is omitted. Therefore, the various components making up the print head 3 are visible, and a number of components are also shown in partial cross-section to improve visibility.

[0153] Figure 3A connector 112 is shown, through which the printhead 3 can be connected to an umbilical cord disposed at the first end 100 of the printhead. The connector 112 is integral with a chassis 114. The chassis 114 defines various platforms upon which various other components are mounted. For example, in the illustrated embodiment, a motor 116 and a high-voltage resistor 118 are mounted to the chassis 114. The high-voltage resistor 118 limits the current and spark energy available to the electrodes (described below). In other embodiments, the high-voltage resistor 118 can be mounted closer to the deflection electrode 168 to reduce the cable length therebetween. Thus, the high-voltage resistor 118 can be mounted, for example, to the chamber housing 162 or the PCB 167. A solenoid valve 120 is also mounted to the chassis 114. In the illustrated embodiment, the solenoid valve 120 is mounted to the chassis 114 via a valve manifold. In the illustrated embodiment, the motor 116 is a stepper motor, but other types of motors (e.g., a brushless DC motor, a linear motor, a solenoid, or other suitable actuator) may be used.

[0154] The shaft of the motor 116 rotates about an axis of rotation 117, which may be referred to as the motor axis. The motor 116 is arranged in power communication with a rotatable body 122 which forms part of a sealing mechanism 124. The sealing mechanism 124 is located at the second end 102 of the print head 3 and, as mentioned above, is the particular focus of the present application. In short, the rotatable body 122 is rotatable about the axis of rotation 126. The rotatable body 122 can be in a first configuration and a second configuration (e.g., Figure 3 106), in the first configuration, the ink path is defined across the rotatable body 122 and through the ink hole 106, and in the second configuration, the rotatable body 122 closes the ink hole 106. In the second configuration, the sealing mechanism 124 (particularly the rotatable body 122 thereof) seals a portion (i.e., a chamber) of the printhead 3 to allow flushing of the portion with a cleaning fluid to clean the printhead 3.

[0155] As previously described, the motor 116 is in power communication with the rotatable body 122 to drive the rotation of the rotatable body 122. The motor 116 is in power communication with the rotatable body 122 via the shaft 128. The shaft 128 is disposed in a chamber that is selectively sealed by the rotatable body 122 (e.g., see Figure 7 The shaft 128 extends along the extent of the chamber. The shaft 128 is in power communication with the rotatable body 122 via a worm gear 130 including a worm 132 and a gear 134. The worm 132 is coupled to an end of the shaft 128 (e.g., near the second end 102 of the print head 3). The gear 134 is rotatably coupled to the rotatable body 122. The worm gear 130 changes the direction of rotation of the shaft 128 from the rotation axis 129 to the rotation axis 126. Although Figure 31, but another worm gear is used to change the direction of rotation of the motor 116 at the obscured end of the shaft 128 (e.g., located toward the first end 100 of the printhead 3). As described above, the shaft 128 rotates about the axis of rotation 129. The axis of rotation 129 extends in a longitudinal direction along the printhead 3, and the printhead 3 can be described as extending generally in the same longitudinal direction.

[0156] The use of a drive assembly comprising shaft 128 and worm gear 130 is advantageous for a number of reasons. First, the incorporation of shaft 128 means that motor 116 can be located in a separate portion of printhead 3 from the rest of sealing mechanism 124. This is desirable because the longitudinal extent of printhead 3 at second end 102 is not increased beyond what is necessary (e.g., to accommodate the volume of the motor). Increasing the longitudinal extent of printhead 3 at second end 102 reduces the risk of the throw distance that printhead 3 must be offset from the substrate to be printed. The use of worm gear 130 is also advantageous, at least because the transmission effectively increases the torque output transmitted by motor 116 to rotatable body 122. This is particularly desirable in situations where rotatable body 122 may become partially stuck in position (e.g., due to stiction) after a cleaning process and subsequent drying process. In other words, the use of worm gear 130 reduces the risk of rotatable body 122 becoming stuck, preventing the drive assembly from rotating it about axis of rotation 126.

[0157] Returning to describing the other components of the printhead 3, a manifold 136 is coupled to the chassis 114. Various fluid and electrical connections extend through the manifold 136.

[0158] Nozzle housing 138 (in Figure 3 The nozzle assembly 140 is coupled to the manifold 136 and houses the nozzle assembly 140. The nozzle housing 138 may also be described as a body forming part of the housing. The nozzle assembly 140 includes, among other components, a nozzle carrier 142 and a nozzle body 143. The nozzle body 143 defines nozzles for generating and ejecting a stream of ink droplets for printing. Figure 3 not visible in the ).

[0159] The charging electrode assembly 146 is coupled to the nozzle assembly 140. The charging electrode assembly 146 includes a charging electrode 148 and an insulating coupling 150 coupled to the charging electrode 148. When a stream of ink droplets is directed past the charging electrode 148 in use, they are selectively and individually imparted with a predetermined level of charge by the charging electrode 148. To help align the charging electrode 148 relative to the stream of droplets emitted from the nozzle of the nozzle body 143, the charging electrode 148 is rotatably adjustable about an axis. Figure 3It can be seen that a boot 151 is sandwiched between the charging electrode 148 and the chamber housing 162. The boot 151 allows the charging electrode 148 to remain in sealing engagement with the chamber housing 162 (see also FIG. Figure 7 / 8), while the charging electrode 148 is adjusted.

[0160] Return to Figure 3 , chamber housing 162 (in Figure 3 The chamber housing 162 is coupled to the nozzle housing 138 (also shown in partial cross-section). The chamber housing 162 defines a chamber 164. The chamber 164 may also be described as a cleaning chamber. Although further information related to the chamber 164 will be provided in the following figures (particularly the chamber 164 in FIG. Figure 7 and Figure 8 106 ), but when rotatable body 122 is in the second configuration with ink orifice 106 closed, chamber 164 is sealed for cleaning. Thus, when sealed, cleaning fluid is directed or flushed into chamber 164 and through chamber 164, cleaning chamber 164 and associated components of printhead 3 disposed therein. Directing cleaning fluid into chamber 164 may include pumping the cleaning fluid (e.g., via an upstream pump under positive pressure) and / or extracting the cleaning fluid (e.g., via a downstream pump under negative pressure).

[0161] A low voltage (e.g., ground or negative potential) electrode 166 and a deflection (e.g., high voltage) electrode 168 are coupled to the chamber housing 162 and mounted within the chamber 164. The electrodes 166, 168 may be collectively referred to as a pair of deflection electrodes. The low voltage electrode 166 may also include a phase detector that detects the phase of the charged particles during operation. The low voltage electrode 166 may be coupled to the chamber housing 162 via an adhesive. In other embodiments, the low voltage electrode 166 may be coupled to the chamber housing 162 via a gasket. The deflection electrode 168 is used to direct the stream of ink droplets ejected by the nozzle and charged by the charge electrode 148 away from the gutter and toward the ink orifice 106 for printing onto the substrate during use. The deflection electrode 168 is disposed within the chamber 164 and, therefore, can be cleaned when the chamber 164 is sealed and a cleaning process is performed.

[0162] The printhead 3 also includes a housing 170. Housing 170 forms part of the sealing mechanism 124. Housing 170 is coupled to the chamber housing 162. Housing 170 sealingly engages chamber housing 162 via a gasket 173, which is inserted between chamber housing 162 and housing 170. Housing 170 may also be described as a rotatable body mount or housing. As will be described in detail later in this document, rotatable body 122 is rotatably mounted within housing 170 to selectively open and close ink orifice 106. Housing 170 also includes a cover 172 that is selectively removable from the rest of housing 170 to facilitate installation and maintenance of the moving portion of sealing mechanism 124 (e.g., rotatable body 122). Housing 170 also includes an end cap 104 that defines ink orifice 106. Therefore, housing 170 may be referred to as defining ink orifice 106. Although in the illustrated embodiment, ink orifice 106 is specifically defined by end cap 104, in other embodiments, end cap 104 may be omitted. Thus, even without end caps, the housing 170 can define the ink orifice. It is also noteworthy that, in the illustrated embodiment, the ink orifice 106 is downstream of the rotatable body 122. That is, the ink droplet stream first passes through the rotatable body 122 and then through the ink orifice 106. In other embodiments, the rotatable body can define the most downstream point of the ink path, such that no end caps are positioned downstream of the rotatable body. In such embodiments, the surrounding housing can be considered to define the ink orifice across the rotatable body.

[0163] For the avoidance of doubt, in the illustrated embodiment, the end cap 104 is coupled to the chamber housing 162 and does not move during operation. That is, the end cap 104 is fixed in place. However, in other embodiments, the end cap may define at least a portion of the rotatable body of the sealing mechanism. For example, the end cap may be rotatable about an axis that is generally parallel to the axis 129. The rotational position of the end cap may determine the extent to which the ink aperture of the end cap overlaps with the ink aperture of an adjacent housing to "open" the ink aperture of the adjacent housing. Where the ink apertures at least partially or completely overlap, the rotatable body (e.g., the end cap) may be said to be in a first configuration, wherein the ink path is defined across the end cap. Where the ink apertures of the end cap do not overlap with the ink apertures of an adjacent housing, the rotatable body (e.g., the end cap) may be said to be in a second configuration, wherein the ink apertures of the housing are closed.

[0164] Despite Figure 3 The various fasteners used to couple the chassis 114, manifold 136, nozzle housing 138, chamber housing 162, and outer shell 170 together are shown, but for the sake of brevity, are not annotated or described in detail herein.

[0165] If it will Figure 7As will be appreciated, the chamber 164 is defined by the combination of the chamber housing 162 and the outer shell 170. The chamber 164 has a lower surface defined by the combination of the low voltage electrode 166 (e.g., by surface 166a) and the surrounding chamber housing 162 (e.g., surface 162a), and an upper surface that extends above the deflection electrode 168 (i.e., such that the deflection electrode 168 is disposed within the chamber 164) and is at least wide enough to accommodate the deflection electrode 168. A third surface 164c and a fourth surface 164d (which may be referred to as side surfaces) of the chamber 164 extend between the first surface 164a and the second surface 164b to define the perimeter of the chamber 164. The fourth surface 164d extends between the first surface 164a and the second surface 164b to define the perimeter of the chamber 164. Figure 7 Not visible in.

[0166] refer to Figure 3 , the print head 3 further includes a PCB 167, which is mounted in the chamber housing 164. However, as Figure 7 As shown, the PCB is not disposed within the cavity 164 .

[0167] Go to Figure 4 , provides an alternative perspective view of the print head 3. Due to the different viewing angles, Figure 3 Multiple components that are not visible or only partially visible in Figure 4 Visible in.

[0168] Starting from the first end 100 of the print head 3, the connector 112 and the integral chassis 114 are shown. The solenoid valve 120 is shown mounted to the chassis 114 along with the valve block 174. Figure 4 Also visible is the worm gear 176 including the worm 178 and the gear 180. The worm 178 is rotatably coupled to the motor 116, which is visible only on the opposite side of the chassis 114, as shown in FIG. Figure 4 shown (and in Figure 3 176). Worm gear 178 is driven to rotate about axis of rotation 117. Worm gear 178 is arranged in driving communication with gear 180, which is rotatably coupled to shaft 128. Gear 180 and shaft 128 are thus driven to rotate about axis of rotation 129, which may be referred to as the shaft axis. It will be appreciated that by using worm gear 176, the direction of rotation driven by motor 116 is effectively translated by 90°, which is advantageous due to space limitations within printhead 3. Shaft 128 is shown extending across the entire extent of each of manifold 136, nozzle housing 138, chamber housing 162, and partially through housing 170.

[0169] If combined Figure 3 As mentioned above, the manifold 136, nozzle housing 138, chamber housing 162 and housing 170 are also coupled to the chassis 114. PCB 167 is Figure 4The nozzle assembly 140 and the charging electrode assembly 146 coupled to the nozzle housing 138 are also shown in FIG. Figure 4 The middle part is visible.

[0170] Turning briefly to the sealing mechanism 124 at the second end 102 of the printhead 3, as previously described, the sealing mechanism 124 comprises a housing 170 (which includes a cover 172 and the end cap 104) and a rotatable body 122. The ink aperture 106 defined by the housing 170 is also visible.

[0171] It is worth noting that a component that has not been described in detail in connection with the print head 3 is a component of the slot. The print head 3 does contain a slot, which in the embodiment shown is a fixed slot coupled to the housing 170. Figure 6 Provide gutter details forward.

[0172] Go to Figure 5 , provides an enlarged perspective view of a portion of the print head 3. Figure 5 It will be appreciated that the motor 116 is partially visible, as is the chassis 114, but any components further towards the first / connector end of the print head 3 are not visible. Figure 3 and Figure 4 The chamber housing 162 is shown in Figure 5 Not shown in the figures to facilitate visibility of the components housed therein.

[0173] Figure 5 The geometry of the deflection electrodes 168 is shown, which are used to direct the ink drop stream towards the substrate to be printed.

[0174] Figure 6 is a perspective view of a subassembly of the print head 3. Figure 6 The chamber housing 162 is shown with the nozzle assembly 140 and the sealing mechanism 124 coupled to the chamber housing 162 .

[0175] As previously mentioned, the various components of the sealing mechanism 124 are visible, including the rotatable body 122, the housing 170 (including the cover 172), and the worm 132 and gear 134. Figure 6 Also visible is the slot block 182. The slot block 182 will be described in more detail in conjunction with subsequent figures, but in brief, the slot block 182 includes a slot ( Figure 6 The ink droplets not used for printing are received through this slot and then recirculated back to the mixing tank of the ink system (as shown in the figure). Figure 9 In the illustrated embodiment, the slot block 182 is a separate component from the surrounding housing 170 and other components. However, in some embodiments, the slot can be integral to the rotatable body (e.g., see Figures 17 and 18).

[0176] The tank block 182 also includes a recess 200 defined in the effective underside of the tank block 182. The recess 200 leads to a port 202. The port 202 further defines a second conduit (e.g., Figure 9 214 shown). Due to the presence of the recess 200, even when the rotatable body 122 is in the Figure 6 In the second, closed configuration shown, the second conduit is still arranged in fluid communication with the chamber. Thus, clean fluid can be pumped or drawn into the chamber via the second conduit, or used (e.g., dirty) clean fluid can be pumped or drawn out of the chamber via the second conduit. Further details in this regard are provided below.

[0177] Figure 6 The figure also schematically shows first and second cross-sectional marks 184 and 186, where 184 is a vertical cross-sectional mark and 186 is a horizontal cross-sectional mark. The marks 184 and 186 correspond to Figure 7 and 8 Cross-sectional views provided in .

[0178] Go to Figure 7 , provides Figure 6 A cross-sectional side view of the subassembly shown in FIG. Figure 6 See note 184 in [Chapter 184]. Figure 7 A chamber 164 is shown that may be selectively sealed by the sealing mechanism 124 .

[0179] from Figure 7 Starting at the right-hand end of the nozzle assembly 140, only a portion of the nozzle body 143 is visible. The nozzle body 143 holds the nozzle 144, which generates and ejects a stream of ink droplets 188 for printing. Downstream from the nozzle 144 is a charging electrode 148. The charging electrode 148 is coupled to an insulating coupling 150. In the illustrated embodiment, the charging electrode 148 is rotatably coupled to the insulating coupling 150 via fasteners 147 and 149. The insulating coupling 150 (and thus the charging electrode 148) is rotatably adjustable relative to the nozzle body 143. The insulating coupling 150 is an insulator (which may be plastic) that separates the charging electrode 148 from the nozzle body 143 (which is grounded). The charging electrode 148 abuts a protective shield 151, such that the protective shield 151 is sandwiched between the charging electrode 148 and the chamber housing 162. Protective cover 151 also facilitates adjustment of charging electrode 148 relative to chamber housing 162 by allowing a degree of movement of charging electrode 148 relative to chamber housing 162 .

[0180] The charging electrode 148 is arranged to communicate with the chamber 164 through the passage 189. In use, as Figure 7As shown, a stream of ink drops 188 is generated and ejected by the nozzle 144 and travels through the chamber 164 via the charge electrode 148 and the first channel 189. After passing through the charge electrode 148, the stream of ink drops 188 has a charge applied thereto. The selectively charged stream of ink drops 188 can be selectively deflected by the deflection electrode 168 for printing. The stream of ink drops that has been deflected by the deflection electrode 168 for printing is then Figure 7 The ink drop stream that is not used for printing and therefore not deflected by the deflection electrode 168 is labeled 194. The ink drop stream 194 that is not used for printing is received by the slot hole 183 of the slot block 182. A portion of the slot conduit 196 defined by the slot hole 183 is located at Figure 7 This is the conduit through which the ink drops 194 that are not used for printing and that are received by the slots 183 travel.

[0181] For the sake of completeness, in Figure 7 , the rotatable body 122 of the sealing mechanism 124 is shown in the second closed configuration. Thus, when the sealing mechanism 124 is in Figure 7 In the configuration shown, the drop streams 188, 190, 194 will not be present. Figure 7 The slot block 182 is shown at least partially contained by the housing 170, and although Figure 7 Not visible in FIG, but chamber 164 also extends behind slot block 182, as shown in FIG. Figure 7 (e.g., extending into the plane of the page). However, this Figure 8 is visible and will be combined Figure 8 Provide a description.

[0182] Return to Figure 7 , also shown is a sealing mechanism 124 comprising a rotatable body 122 rotatably coupled to a gear 134. A shaft 198 of the rotatable body 122 is also visible. In use, the rotatable body 122 rotates about the shaft 198 about the axis of rotation 126. The shaft 198 is received by a recess 199 of the cover 172 to constrain and position the rotatable body 122.

[0183] The ink hole 171 defined by the housing 170 is Figure 7 It can also be seen in Figure 7 In the configuration shown, the rotatable body 122 effectively closes the ink hole 171. In the first open configuration, wherein the rotatable body 122 is relative to Figure 7 , the ink orifice 171 is effectively opened so that a stream of ink droplets 190 can pass through the rotatable body 122 via the ink path 190 through the ink orifice 171. As the stream of ink droplets 188 passes through the chamber 164, a phase detector forming part of the low voltage electrode 166 also operates to detect the phase of the ink particles. Figure 2As shown, the end cap 104 defines an ink orifice 106 . Figure 7 The ink aperture 171 shown in FIG. 1 overlaps with the ink aperture 106 defined by the end cap 104 , and the ink aperture 106 can therefore also be considered to be opened / closed by the rotatable body 104 (at least by virtue of being downstream of the ink aperture 171 ).

[0184] at last, Figure 7 Also shown is a recess 200 defined in the slot block 182. Figure 6 As mentioned, the recess 200 partially defines a port 202 for cleaning and draining.

[0185] Go to Figure 8 , provides Figure 7 An alternative cross-sectional view to the cross-sectional view shown. Figure 8 In, through Figure 6 The cross-sectional view indicated in Note 186 shows Figure 6 and Figure 7 Therefore, Figure 8 Can be described as a cross-sectional plan view of a subassembly.

[0186] If combined Figure 7 As stated, Figure 8 Also shown are the nozzle body 143 , insulating coupling 150 , charging electrode 148 , and protective cover 151 . Figure 8 Also shown is a low voltage electrode 166 located within chamber 164. Figure 8Also visible are phase detector electrode 166b (which may be referred to as a phase pickup electrode) and velocity detector electrode 166c. Electrodes 166b, 166c (and low-voltage electrode 166) are etched into the PCB that defines low-voltage electrode 166 (e.g., the rear portion of the PCB in the illustrated embodiment). The combination of electrodes 166, 166b, and 166c may be referred to as a phase detector assembly. Phase detector electrode 166b is configured to determine the magnitude of the charge applied to an ink droplet as it moves past phase detector electrode 166b. Measurements from phase detector electrode 166b are used to determine when to apply voltage to charge electrode 148. Velocity detector electrode 166c is configured to determine the velocity of an ink droplet as it moves past electrode 166b. Velocity is determined by measuring the time between a charge "pulse" detected by phase detector electrode 166b and subsequently by velocity detector electrode 166c, and dividing the distance between electrodes 166b and 166c by this time. In the illustrated embodiment, the low-voltage electrode 166 is in the form of an electroless nickel immersion gold (ENIG)-coated copper ground plate. The low-voltage electrode 166 serves as a 0V plate for the deflection electrode, which establishes the EHT field that deflects the ink droplet stream during use. The phase detector electrode 166 b and the velocity detector electrode 166 c are covered by an insulator (e.g., solder resist in the illustrated embodiment). This prevents ink and / or solvents from shorting the electrodes 166 b and 166 c to the low-voltage electrode 166 .

[0187] Since the phase detector electrode 166b, the speed detector electrode 166c, the low voltage electrode 166 and the deflection electrode 168 ( Figure 8 Each of the components (not shown) is located within the chamber 164 so that all of these components can be cleaned during the cleaning cycle. Similarly, the charging electrode 148, although located outside the chamber 164, can also be cleaned by means of a third port or charging electrode drain ( Figure 8 (not visible in the image) are cleaned during the cleaning cycle.

[0188] Figure 8 In the illustrated embodiment, chamber 164 is shown to include a first chamber portion 164g and a second chamber portion 164h. First chamber portion 164g is defined by chamber housing 162. Second chamber portion 164h is defined by housing 170. Thus, in the illustrated embodiment, chamber 164 can be said to be at least partially defined by housing 170. In other embodiments, it should be understood that chamber housing 162 can be integral with housing 170, such that chamber 164 is completely defined by housing 170.

[0189] Figure 8Chamber housing 162 is also shown to include a (first) conduit 204 that extends partially through chamber housing 162 and communicates with chamber 164 via port 206. Thus, port 206 can be said to at least partially define chamber 164. Conduit 204 is multipurpose, as it can be used to supply cleaning fluid to chamber 164 or drain spent cleaning fluid from chamber 164. Thus, conduit 204 can be described as a chamber purge and drain passage. Conduit 204 can be specifically described as an upstream chamber purge / drain passage, as it is disposed adjacent to passage 190, through which ink droplets are ejected into chamber 164.

[0190] Figure 8 Further features of the slot block 182 are also shown. Figure 7 As described above, the tank block 182 includes a slot 183 through which ink droplets not used for printing are received / collected. Slot 183 defines the upstream end of a tank conduit 196, which extends through the tank block 182. At a downstream point, the tank conduit 196 appears to branch into a recess 210. Recess 210 is sealed during use and merely facilitates the creation of the tank conduit 196 through the tank block 182. Further downstream of the tank conduit 196 is a return conduit 212, at least partially defined by the chamber housing 162. Return conduit 212 is provided in fluid communication with the tank conduit 196, and therefore with the slot 183. Thus, ink droplets not used for printing are received by the slot 183 and drawn through the tank conduit 196 and return conduit 212 by suction. The unused ink droplets are then returned to the mixing tank. For completeness, the tank block 182 is sealed to the chamber housing 162 by a seal 213.

[0191] In the illustrated embodiment, the slot block 182 forms a separate component that is fixedly coupled to the chamber housing 162. In other embodiments (e.g., FIG. 17, FIG. 18), at least a portion of the slot may be rotatably coupled to the rotatable body 122 and may be integral therewith. Figure 8 The recess 123 of the rotatable body 122 is partially shown in FIG.

[0192] When the rotatable body 122 is in the Figure 8 In the second configuration shown, in which the rotatable body 122 closes the ink orifice 171, the slot block 182 is partially received by the recess 123 of the rotatable body 122. When the rotatable body 122 is in the first configuration, in which the ink path is defined across the rotatable body 122 and through the ink orifice 171, the rotatable body 122 is effectively rotated approximately 90° counterclockwise so that the slot block 182 is still partially received by the recess 123, but in a different orientation. This will be combined with Figure 10 and Figure 11 Describe in more detail.

[0193] Now refer to Figure 9 , shows the Figure 1 Schematic diagram of a fluid system of a printer, including a printhead 3. Inkjet printer 1 includes an ink system 5 contained within a main printer body 2. Ink system 5 includes at least components forming part of a main ink block 11. The ink system may also include a cartridge module 12 and a cleaning module 13. Components of the printhead are schematically indicated at 3.

[0194] Starting with the main ink block 11, the main ink block 11 includes a mixing tank 17 (which may also be referred to as an ink supply tank or ink supply tank) configured to supply ink along a main supply line 19. Ink is drawn from the mixing tank 17 by an ink pump 21. The ink also passes through a first filter 23, located along the main supply line 19, downstream of the ink pump 21. The first filter 23 removes any particulate matter (e.g., sediment) contained within the mixing tank 17. In the illustrated embodiment, the first filter 23 is a 100-micron filter, but it should be understood that filters of other sizes may be used. A venturi line 24 connects to the main supply line 19 downstream of the first filter 23. Disposed along the venturi line 24 is a venturi tube 24a (e.g., a restriction). In operation, fluid (e.g., an ink mixture) continuously circulates from the mixing tank 17 through the main supply line 19, through the venturi line 24, and thus through the venturi tube 24a, before returning to the mixing tank 17. This continuous circulation, combined with the venturi 24a, creates suction to draw fluid into the mixing tank 17 via a refill line 25 that extends between the cartridge module 12 and the venturi 24a. Fluid is drawn into the mixing tank 17 through the venturi 24a and the downstream portion 24b of the venturi line 24.

[0195] The ink pump 21 can be operated as a pressure-controlled pump, meaning that the ink flow rate through the pump 21 will be adapted as needed to maintain a target pressure downstream of the ink pump 21 (e.g., as monitored by the pressure sensor 33). The ink pump 21 can be configured to supply ink to the printhead 3 at a predetermined system operating pressure, which can be determined based on the printer configuration (e.g., nozzle geometry). For example, a nozzle with a diameter of 75 μm may require a lower operating pressure than a nozzle with a diameter of 62 μm to achieve similar jetting performance (e.g., droplet break-off position or break-off flight time). The system operating pressure can also vary depending on other system parameters (e.g., ink type, viscosity).

[0196] A second filter 26 with a 5-micron filter size is positioned downstream of the first filter 23 along the main supply line 19. A damper 27 is positioned downstream of the ink pump 21 and downstream of the second filter 26 to reduce fluctuations in ink pressure within the ink supply. Downstream of the damper 27, a load line 28 branches off from the main supply line 19. The load line 28 includes a flow restrictor 29. The load line 28 is configured to maintain a near-constant load on the main supply line 19, thereby avoiding pressure spikes in the printhead 3 caused by load spikes on the ink pump 21 (e.g., upon activation of the ink pump 21). A viscometer valve 30 is positioned along the load line 28. The viscometer valve 30 selectively places the load line 28 in fluid communication with the mixing tank 17 or the viscometer 32 via a tank line 31. The default configuration of the viscometer valve 30 places the load line 28 in fluid communication with the mixing tank 17. This creates a circular fluid flow path. When it is desired to determine the viscosity of the ink mixture in the main supply line 19, and therefore the load line 28, the viscometer valve 30 is energized to direct flow into the viscometer 32. Initially, the viscometer 32 is empty. By monitoring the time it takes to fill and / or empty the viscometer 32, and based on the known volume of fluid in the viscometer 32, the viscosity of the ink mixture can be determined.

[0197] Downstream of the damper 27 and the load line 28, a pressure sensor 33 is connected to the main supply line 19 and is configured to monitor the pressure downstream of the ink pump 21. The ink pump 21 can be operated as a constant pressure pump (i.e., the pump is controlled to maintain a constant output pressure). A third filter 34 having a filter size of 15 microns is provided downstream of the pressure sensor 33.

[0198] The main supply line 19 is configured to carry ink from the ink mixing tank 17 along the umbilical cord 4 to the printhead 3. The main supply line 19 is connected to the printhead 3 via a feed valve 35. The feed valve 35 is configured to control the supply of ink to the printhead 3. A heater 36 is provided downstream of the feed valve 35. The heater 36 is used to control the temperature of the ink mixture. Controlling the temperature of the ink mixture reduces the effects of temperature fluctuations on the viscosity of the ink mixture. For example, activation of the heater 36 provides a heating effect that reduces the viscosity of the ink mixture. A temperature sensor 37 is provided downstream of the heater 36. The heater 36 is provided in fluid communication with the nozzle body 143, and therefore with the nozzle 144, via a nozzle line 38. The heater 36 preferably maintains the temperature of the ink mixture at at least approximately 308°K (e.g., approximately 35°C).

[0199] As described above, ink is fed to the printhead 3 along the main supply line 19 via the umbilical cord 4. Within the printhead 3, the ink is supplied to the nozzles 144. The ink is supplied to the nozzles 144 under pressure (under the influence of the ink pump 21) and forms an ink jet. The ink jet begins as a constant stream of ink and, under the influence of surface tension and vibrations applied in the nozzle body 143 (e.g., by a piezoelectric oscillator), gradually separates into a series of ink droplets 188, which continue to travel in the direction of the ink jet 57.

[0200] Soon after being ejected from the nozzle 144 of the nozzle body 143, the ink jet passes through the charging electrode ( Figure 9 Not shown, but in Figure 3 The point at which the continuous ink jet separates into droplets 188 is arranged to occur within the charging electrode. The ink is a conductive liquid, and the nozzle body 143 is typically maintained at a fixed (e.g., ground) potential. A variable voltage is applied to the charging electrode ( Figure 9 Not shown, but in Figure 3 The charge electrode (indicated by 148 in the figure) induces a charge on the continuous stream of ink droplets extending from the nozzle body 143 toward the charge electrode. When the continuous ink stream (i.e., the ink jet) separates into droplets 188, any charge induced on the ink within the droplets is captured at the moment the individual droplets "pop" out of the main ink stream. In this way, a variable charge can be applied to each droplet within the ink droplet stream 188.

[0201] The ink droplet stream 188 then continues from the charging electrode through the other electrode ( Figure 9 Not shown, but in Figure 3 166 and 168 in FIG. A first electrode (e.g., a low-voltage electrode) is maintained at a first voltage, while a second electrode (e.g., a deflection electrode) is maintained at a second voltage, establishing a large potential difference (e.g., 8-10 kilovolts) between the electrodes. In some systems, one electrode may be maintained at ground potential, while the other is maintained at a high (positive or negative) voltage (relative to ground). In other systems, one electrode is maintained at a negative voltage (relative to ground), while the other is maintained at a positive voltage (relative to ground). The electric field established between the electrodes causes any charged droplets (i.e., those already charged by the charge electrode) to be deflected. In this way, based on the variable charge applied by the charge electrode, droplets 188 can be selectively (and variably) diverted from the path along which they are emitted from nozzle 144.

[0202] The droplets that pass through the deflection field and are deflected by the electrodes are not Figure 9 shown in Figure 7 The ink droplet stream 190 is used for printing. The ink droplet stream 190 can be described as defining an ink path across the rotatable body (of the sealing mechanism) and through the ink orifice.

[0203] Return to Figure 9 Droplets that pass through the deflection field without being deflected (i.e., droplets not used for printing) travel to gutter 40 (e.g., gutter block 182 of the previous figures). Gutter 40 includes an orifice 183 (e.g., gutter hole 183 of the previous figures) into which droplets enter. Gutter 40 is connected to a gutter line 42 that extends from gutter 40 back to the main ink stick 11 (e.g., gutter line 42 extends between at least gutter 40 and gutter pump 46). A gutter valve 44 is optionally provided within gutter line 42 to enable gutter line 42 to be opened and closed. Suction is applied to gutter line 42 by gutter pump 46 to draw ink along the line from gutter 40 back toward the main ink stick 11. In other embodiments, suction may be provided by a venturi tube in communication with ink pump 21.

[0204] Tank valve 48 is positioned downstream of gutter pump 46. Tank valve 48 selectively places gutter pump 46 in fluid communication with either mixing tank 17 or solvent tank 50 (which may be described as a "spent" solvent reservoir). In the illustrated embodiment, solvent tank 50 is positioned adjacent to mixing tank 17. In the illustrated embodiment, solvent tank 40 and mixing tank 17 are shown as distinct compartments within the overall tank, but in other embodiments, mixing tank 17 and solvent tank 40 may be physically separate tanks. During printing operations, tank valve 48 places gutter pump 46 in fluid communication with mixing tank 17. The ink mixture (e.g., ink droplet stream 188) received by gutter 40 is thus returned to mixing tank 17 and can be recirculated / reused at a later time. During non-printing operations (e.g., such as priming, cleaning, etc.), tank valve 48 places gutter pump 46 in fluid communication with solvent tank 50. This is to prevent cleaning fluid (e.g., "spent" solvent) from undesirably contaminating the ink mixture in mixing tank 17 (e.g., changing the viscosity of the ink mixture).

[0205] In addition to recirculating unprinted ink droplets through gutter 40, any air drawn into gutter 40 is also conveyed to mixing tank 17 or solvent tank 50. Mixing tank 17 and solvent tank 50 are connected via condenser 52 (which also serves as an exhaust port). The solvent in the ink mixture in mixing tank 17 tends to evaporate as solvent vapor within mixing tank 17. Saturated solvent vapor therefore remains in mixing tank 17 during use. When this vapor passes through condenser 52, the relatively cool surface of condenser 52 causes the solvent contained in the vapor to condense. Consequently, the solvent vapor returns to liquid and is deposited back into solvent tank 50. This advantageously avoids excessive solvent loss from the system (which would otherwise occur if both tanks were vented directly to atmosphere). Furthermore, mixing tank 17 is effectively vented by condenser 52, preventing excessive pressure buildup within mixing tank 17. Exhaust gas from mixing tank 17 thus travels to solvent tank 50. Conversely, solvent tank 50 is vented via solvent tank vent line 54, which is in fluid communication with solvent tank 50. Through the solvent tank exhaust line 54, the gases may be exhausted, preferably to the exterior of the printer cabinet (where the ink system is housed).

[0206] The ink system, and in particular the cartridge module 12 thereof, includes an ink cartridge connector 56 that can be connected to an associated ink cartridge 8 and a solvent cartridge connector 58 that can be connected to an associated solvent cartridge 10. The ink cartridge 56 and the ink cartridge connector 58 are connected to the refill line 25, thereby allowing ink or solvent to be drawn into the mixing tank 17 through the venturi line 24. In other embodiments, a dedicated transfer pump can be used instead of the venturi line 24.

[0207] By using the venturi in this manner (i.e., as a jet pump), a system can be designed in which the main system ink pump 21 can generate both positive pressure (e.g., to supply ink to the printhead 3) and negative vacuum pressure (e.g., to draw ink or solvent into the mixing tank 17 via the refill line 25).

[0208] The feed valve 27 provided along the main supply line 19 is configured to prevent the main supply line 19 from being continuously open. However, because the feed valve 27 is provided downstream of the venturi line 24, even when the feed valve 27 is closed, when the ink pump 21 is operating, ink will flow along the venturi line 24 through the venturi tube 24a, thereby causing suction to be applied to the refill line 25. In this way, suction can be applied even when ink is not being supplied to the printhead 3. Of course, the second valve 61 can also be operated to block the refill line 25, meaning that refill line suction can be controlled independently of the venturi tube 24a.

[0209] It should be understood that by selectively activating one or more of the four cartridge valves 60, 61, 62, 63, the ink cartridge 56 can be placed in fluid communication with the refill line 25. For example, opening only the first valve 60 and the second valve 61 (and closing the third valve 62 and the fourth valve 63) places the ink cartridge 8 in fluid communication with the refill line 25 via the ink refill line 59. Ink can thus be drawn into the mixing tank 17 via the ink refill line 59 and the refill line 25 to add ink to the mixing tank 17.

[0210] Solvent can be directed from the solvent cartridge 58 to the solvent tank 50 via a solvent refill line 64 and a solvent tank line 65. Closing the first and second valves 60 and 61, and opening the third and fourth valves 62 and 63, places the solvent cartridge 10 in fluid communication with the solvent tank 50 via the solvent tank line 65 and the solvent refill line 64. Solvent can also be drawn from the solvent tank 50 through the solvent tank line 65 and into the purge module inlet line 72 (described below). A solvent tank refill line filter 66 is positioned along the solvent tank refill line 64. A solvent pump 67 is positioned downstream of the solvent cartridge 10 along the solvent refill line 64. Activation of the solvent pump 67 can be used to pump solvent from the solvent cartridge 10 into the solvent tank 50. Advantageously, the amount of solvent added to the solvent tank 50 can be measured by determining the fluid level within the solvent tank 50. This volume can then be subtracted from the remaining solvent cartridge volume stored on the smart chip on the solvent cartridge 10. Thus, the remaining volume of solvent in the solvent cartridge 10 can be determined. This has been found to be more accurate than measuring the volume of solvent drawn from the solvent cartridge 10 under negative pressure (as the vacuum level within the cartridge typically changes as the cartridge is emptied of fluid). In the embodiment shown, solvent is pumped out of the solvent cartridge 10 by solvent pump 67 .

[0211] When it is desired to add solvent to mixing tank 17, second valve 61 and fourth valve 63 are opened, and first valve 60 and third valve 62 are closed. Solvent is then drawn from solvent reservoir 50 into mixing tank 17 via solvent tank line 65 and refill line 25 through venturi 24a.

[0212] Activation of solvent pump 67 can also be used to pump solvent from solvent cartridge 10 along solvent refill line 64 for non-printing operations, such as priming the fluid circuit. In the illustrated embodiment, solvent pump 67 is not used to actively pump pressurized cleaning fluid (e.g., solvent) into chamber 164 via cleaning module inlet line 72 for cleaning. Instead, cleaning fluid is preferably drawn into chamber 164 under vacuum for cleaning. This provides fail-safe operation if the sealing mechanism fails, as cleaning fluid will not be drawn into chamber 164. If cleaning fluid is pumped into chamber 164 under pressure (e.g., by an upstream pump), a failure of the sealing mechanism risks ejecting cleaning fluid from printhead 3 (e.g., via ink orifices) onto the print line. This poses a risk of undesirable contamination. That is, in some embodiments, cleaning fluid can also be pumped into the chamber.

[0213] A check valve 68 is provided along the solvent refill line 64 downstream of the solvent pump 66 to prevent fluid from traveling past the check valve 68 toward the solvent pump 66. An additional check valve 69 is provided in a branch line that extends around the solvent pump 67. The check valve 69 is an overpressure valve for the solvent pump 67. The check valve 69 is a pressure relief valve that determines the maximum solvent pressure from the solvent pump 67. For completeness, the cartridge valves 60-63 can also be selectively activated to provide other configurations for, for example, priming the fluid system and for draining the mixing tank 17 and / or the solvent tank 50 (e.g., during maintenance).

[0214] A flush line 70 is connected between the third valve 62 and the check valve 68. The flush line 70 connects the cartridge module 12 directly to the printhead 3 via the umbilical cord 4. A flush filter 71 is positioned along the flush line 70, upstream of a cleaning module inlet line 72, which branches off from the flush line 70. The flush line 70 extends to the printhead 3 via a flush valve 73 positioned along the flush line 70. The flush line 70 is used to direct solvent from the solvent cartridge 58 into the nozzle body 143. This allows solvent to be forced through the nozzles 144 to clean the nozzles. This is achieved by activating the solvent pump 67, which provides pressurized solvent to the nozzles 144 for nozzle cleaning. The flush valve 73 is closed by default (e.g., during printing operations) and is only opened during non-printing operations (e.g., priming). Selective activation of valves in the cleaning module 13 prevents solvent from being pumped into the chamber 164 via the cleaning module inlet line 72. In other words, the cleaning module inlet line 72 may be effectively closed by selective activation of a valve in the cleaning module 13 , allowing solvent to flow through the flush line 70 to the flush valve 73 .

[0215] A purge line 74 is connected to the nozzle body 143. It is connected to a purge port 74a on the nozzle body 143. The nozzle body 143 can be provided as part of a nozzle assembly comprising the nozzle body 143 having known acoustic properties and a piezoelectric oscillator. The purge port can be provided by the nozzle body or by a separate component connected to the nozzle body. The purge line 74 allows ink (and / or air and / or debris) to flow out of (or through) the nozzle body 143 via a purge hole 74a (e.g., a purge port) without passing through the nozzle 144, thus allowing cleaning of the nozzle body 143. The purge line 74 extends from the nozzle body 143 along the umbilical 4 and returns ink (or solvent) to the mixing tank 17 depending on the operating stage. The purge line 74 is provided for selective fluid communication with the tank pump 46 via a purge valve 75. Fluid is drawn through the purge line 74 by suction from the downstream tank pump 46. The purge valve 75 is provided along the purge line 74. It should be understood that the vent line is not required and may be omitted in some printers. Incorporating the vent line 74 is advantageous for a number of reasons. The vent line 74 can be used to remove air from the nozzle body 143 (e.g., from within the chamber of the nozzle body 143). Removing air from the nozzle body 143 is desirable because the presence of air can negatively impact the acoustic performance of the nozzle body 143. The vent line 74 can also be used to remove debris that may become trapped in the nozzle chamber when backflushing is performed. Backflushing refers to the process of applying a solvent to the front surface of the nozzle 144 while simultaneously creating a vacuum in the nozzle body. The vent line 74 also allows ink to be removed / drained from the interior of the nozzle body 144, allowing for more efficient cleaning of the interior of the nozzle body 144.

[0216] Thus, the main supply line 19, the drain line 74, the tank line 42, and the flush line 70 connect the ink system (e.g., the main ink block 11 and the cartridge block 12) to the printhead 3. Additional fluid connections housed within the umbilical cord 4 can connect the ink system 5 to the printhead 3. For example, an air recirculation line can be provided to provide solvent-saturated air to the tank line 42 near the tank inlet.

[0217] Chamber 164 is also Figure 9 As shown schematically in Figure 9 As shown, in the embodiment shown, the groove 40 is disposed in the chamber 164. In the embodiment shown, the nozzle body 143 is external to the chamber 164. Two conduits 204, 214 are shown connected to the chamber 164. The first conduit 204 is also Figure 8 . The first conduit 204 is in fluid communication with the chamber 164 via the first port 206. The first port 206 is disposed near the charging electrode and the nozzle body 144 (e.g., at an upstream position within the chamber 164). The second conduit 214 is in fluid communication with the chamber 164 via the second port 202. The second port 202 is disposed near the tank 40 (e.g., Figure 6 The second port 202 is disposed downstream within the chamber 164. The first and second conduits 204, 214, and thus the first and second ports 206, 202, can be used to supply cleaning fluid to or drain spent cleaning fluid from the chamber 164. The first and second conduits 204, 214, and thus the first and second ports 206, 202, can be used to supply air to the chamber 164 (e.g., for drying the chamber or for pressure equalization during printing). Each of the first and second conduits 204, 214 can be selectively opened / closed by actuation of a corresponding valve of the cleaning module 13.

[0218] Figure 9 Also shown is a third conduit 216, which extends from the first conduit 204 to the nozzle body 143 and partially passes through the nozzle body 143. Therefore, the third conduit 216 can be described as a branch of the first conduit 204. The third conduit 216 terminates at a third port 217. The third port 217 is defined in the front face of the nozzle body 143. The third conduit 216 and the third port 217 are optional features of the illustrated embodiment and may be omitted in other embodiments. The third conduit 216 and the corresponding third port 217 are used to supply cleaning fluid to at least a portion of the charging electrode and the downstream chamber, or to drain spent cleaning fluid from the charging electrode and at least a portion of the chamber 164 (or to provide an air supply). Because it is a branch of the first conduit 204, in the illustrated embodiment, the third conduit 216 is not controllable independently of the first conduit 204. In other words, in the illustrated embodiment, when cleaning fluid is supplied through the first conduit 204, the cleaning fluid is ejected from the first port 206 (entering the chamber 164) and the third port 217 (entering at least a portion of the charging electrode). Similarly, when used cleaning fluid is discharged through first conduit 204, the cleaning fluid is discharged from chamber 164 (through first port 206) and from at least a portion of the charging electrode (via third port 217). In certain orientations of the printhead 3 and chamber 164 (e.g., vertically upward), used cleaning fluid can be discharged through both first port 206 and third port 217. Advantageously, first port 206 discharges fluid from chamber 164, while third port 217 discharges fluid from the charging electrode. Thus, the incorporation of third port 217 prevents the accumulation of used cleaning fluid outside of chamber 164, which could undesirably increase the drying time of the printhead 3 after cleaning. However, in other embodiments, one or more valves may be incorporated along first conduit 204 and / or third conduit 216 to provide independent control.

[0219] The third port 217 may also be referred to as a charge electrode drain port.

[0220] Turning to the components of cleaning module 13, first through fourth control valves 80, 81, 82, and 83 are provided. An air line 84 also extends at least partially through cleaning module 13, with an air pump 85 positioned along air line 84. A pressure relief valve 86 is also positioned downstream of air pump 85. Air line 84 is connected to the atmosphere and can be used to selectively supply air to chamber 164. This can be used for positive pressure drying of chamber 164 (e.g., after cleaning) or to provide an air supply into chamber 164 during printing. This is to avoid excessive negative pressure within chamber 164 due to the suction of tank pump 46 via tank 40, which could otherwise cause debris to be drawn from the print line into printhead 3. Advantageously, a single air pump 85 provides both functions.

[0221] Also shown is a downstream portion of cleaning module inlet line 72, which, for the sake of brevity, may be referred to as inlet line 72. The interruption in inlet line 72 between the left-hand side of the figure (i.e., above filter 71) and the right-hand side of the figure (i.e., above air pump 85) is briefly included to improve clarity of the figure and to avoid extending the line through various other components of the fluid circuit. Also shown is an extraction line 87. Extraction line 87 extends via a portion of tank line 42 to tank pump 46. Thus, fluid can be extracted through extraction line 87 by operation of tank pump 46. For the sake of completeness, in the illustrated embodiment, tank valve 87 also forms part of cleaning module 13. However, in other embodiments, tank valve 87 may form part of main ink block 11.

[0222] The first control valve 80 can selectively place the first conduit 204 in fluid communication with the inlet line 72 or the air line 84 (via the second control valve 81 ). The other of the inlet line 72 and the air line 84 can be selectively closed by the first control valve 80 .

[0223] The second control valve 81 can selectively place the first conduit 204 in fluid communication with the extraction line 87 or the inlet line 72 (via the first control valve 80 ) or the air line 84 (via the first control valve 80 ). Figure 9 In the configuration shown, the second control valve 81 places the first conduit 204 in fluid communication with the extraction line 87. Thus, activation of the sump pump 46 applies suction through the extraction line 87 and through the first conduit 204. In this configuration, fluid will be extracted from the chamber 164 through the first conduit 204 and the extraction line 84. Figure 9 In the illustrated configuration, the first conduit 204 is not provided in fluid communication with either the inlet line 72 or the air line 84 .

[0224] The third control valve 82 can selectively place the second conduit 214 in fluid communication with the extraction line 87 or the inlet line 72 (via the fourth control valve 83) or the air line 84 (via the fourth control valve 83). Figure 9In the configuration shown, the third control valve 82 places the second conduit 214 in fluid communication with the extraction line 87. Thus, activation of the sump pump 46 applies suction through the extraction line 87 and through the second conduit 214. In this configuration, fluid will be extracted from the chamber 164 through the second conduit 214 and the extraction line 87. Figure 9 In the illustrated configuration, the second conduit 214 is not provided in fluid communication with either the inlet line 72 or the air line 84 .

[0225] Fourth control valve 83 can selectively place second conduit 214 (via third control valve 82 ) in fluid communication with inlet line 72 or air line 84 . The other of inlet line 72 and air line 84 can be selectively closed by fourth control valve 83 .

[0226] By selectively operating control valves 80-83, various conduits / ports can be placed in fluid communication with inlet line 72, air line 84, and extraction line 87. When connected to inlet line 72, cleaning fluid can be directed into chamber 164 through the conduits / ports. When connected to air line 84, air can be pumped into chamber 164 through the conduits / ports by air pump 85. When connected to extraction line 87, fluid (e.g., spent cleaning fluid) can be extracted from chamber 164 through the conduits / ports and extraction line 87 by gutter pump 46. Air line 84 can be used to pump air into chamber 164 to dry chamber 164 after cleaning fluid has been drawn into and out of chamber 164. Air line 84 can also be used to pump air into printhead 3 (e.g., into chamber 164) to replenish air removed from chamber 164 by gutter 40 (e.g., during printing operations). This advantageously reduces the risk of the pressure within the print head 3 dropping to a level where debris is drawn into the print head 3 from outside the print head 3 .

[0227] In a preferred embodiment, one of first conduit 204 and second conduit 214 is placed in fluid communication with inlet line 72, and the other of first conduit 204 and second conduit 214 is placed in fluid communication with extraction line 87. Activation of sump pump 46 then draws cleaning fluid through inlet line 72 and into chamber 164 via the conduit connected to inlet line 72. Then, under suction from sump pump 46 via extraction line 87, cleaning fluid is withdrawn from chamber 164 via the other conduit (e.g., the conduit of first conduit 204 or second conduit 214 not connected to inlet line 72). Under suction from sump pump 46 via extraction line 87, cleaning fluid is preferably withdrawn from chamber 164 via the same conduit (e.g., the conduit of first conduit 204 or second conduit 214 connected to inlet line 72). The selection of which port is the fill port and which port is the drain port can be based on the orientation of printhead 3 and chamber 164.

[0228] In a preferred embodiment, the cleaning fluid remains / resides in the chamber 164 for a residence time before being subsequently extracted / discharged. Air can be bubbled through the chamber 164 while the chamber 164 is at least partially filled with the cleaning fluid to agitate the cleaning fluid and remove debris within the chamber 164. The chamber 164 can be only partially filled with the cleaning fluid (e.g., approximately half full). The chamber 164 can be mostly filled with the cleaning fluid (e.g., at least about 80% of the volume of the chamber 164 is filled with the cleaning fluid). The chamber 164 can be partially filled with the cleaning fluid in combination with or isolated from the air bubbled through the chamber 164.

[0229] A method of performing a self-cleaning operation on a self-cleaning marking head is now described. In the following examples, the marking head is a self-cleaning print head, such as that described above with respect to FIG. Figures 1 to 9 The print head described is, for example, print head 3, and the industrial printer is a continuous inkjet printer, such as the one described above with respect to Figures 1 to 9 A continuous inkjet printer is described, such as continuous inkjet printer 1. However, in other examples the self-cleaning marking head may be a self-cleaning laser and the industrial printer a laser printer.

[0230] refer to Figure 10, shows a production line 1001 with a continuous inkjet printer 1002 operating on the production line 1001. The continuous inkjet printer 1002 is configured to mark products 1008 traveling along a conveyor belt 1013 (in direction A) using a self-cleaning printhead 1006. The continuous inkjet printer 1002 includes the self-cleaning printhead 1006, a processor 1003 (also referred to as an internal controller), memory 1004, and a transceiver 1005. The processor 1003 controls the continuous inkjet printer 1002 and provides logic for the continuous inkjet printer 1002. That is, when the continuous inkjet printer 1002 is described herein as making decisions or performing actions, the processor 1003 of the continuous inkjet printer 1002 provides that logic or control. The transceiver 1005 of the printer 1002 is connected to a transceiver 1012 of an external controller 1009 via a network 1007. This connection allows data to be transferred between the printer 1002 and the external controller 1009. The network 1007 may be any suitable wired or wireless network that facilitates the transmission of data (e.g., computer data suitable for processing by a processor). The external controller 1009 includes a processor 1010, a memory 1011, and a transceiver 1012. The external controller 1009 may have control of the production line 1001, or at least have visibility into the status of components of the production line. The external controller 1009 may have such visibility via one or more sensors that monitor the production line 1001. The external controller 1009 may be a filling machine, a weighing machine, a cutting machine, or any other production equipment operating on the production line. The external controller 1009 is located in a manner similar to that of the processor 1010. Figure 1 The same location of the production line 1001 in the figure, but it should be understood that the external controller 1009 can be located in the cloud. That is, the external controller can be a server operating in the cloud, and the continuous inkjet printer 1002 can be connected to the external controller 1009 using, for example, the Internet.

[0231] During normal operation of the continuous inkjet printer 1002, products 1008 travel along the conveyor belt 1013 and past the continuous inkjet printer 1002. When a given product 1008 passes adjacent to the self-cleaning printhead 1006 of the continuous inkjet printer 1002, the continuous inkjet printer 1002 marks the product 1008 using the self-cleaning printhead 1006. The marking may be, for example, a best before date, a lot number, a batch number, a barcode, etc.

[0232] A flow chart depicting a method for cleaning the self-cleaning printhead 1006 of the continuous inkjet printer 1002 is provided in FIG. Figure 111. As shown in FIG. 1 . In step S1, the continuous inkjet printer 1002 receives a control signal from the external controller 1009. As described above, the continuous inkjet printer needs to be cleaned. To facilitate cleaning, the external controller 1009 is configured to send a control signal to the continuous inkjet printer 1002, and the control signal is configured to cause the continuous inkjet printer 1002 to perform a self-cleaning operation of the self-cleaning print head 1006. That is, when the continuous inkjet printer 1002 receives the control signal from the external controller 1009, the continuous inkjet printer 1002 performs the self-cleaning operation in response. In this way, greater control over when the continuous inkjet printer 1002 performs maintenance is achieved, because the external controller 1009, which has an overview of the status of the production line 1001, can automatically decide the most appropriate time to perform the self-cleaning operation. For example, the most appropriate time may be the time that provides the least disruption to the normal operation of the production line 1001.

[0233] The external controller 1009 can send a control signal to the continuous inkjet printer 1002 based on the satisfaction of a predetermined condition. For example, the predetermined condition can be the status of the production line 1001 on which the continuous inkjet printer 1002 is operating, such as a stoppage of the production line 1001. That is, the external controller 1009 can determine that the production line 1001 has stopped due to a component failure on the production line 1001 and, in response, generate and send a control signal to the continuous inkjet printer 1002. For example, if the production line 1001 has stopped due to a component failure on the production line 1001, a self-cleaning operation can be performed while the production line 1001 is stopped, thereby taking advantage of unplanned downtime. The predetermined condition can also or alternatively include a predetermined time. For example, if it is known that the production line 1001 will stop at a specific time in the future, such as due to scheduled maintenance or a planned replacement of a product on the production line, the external controller 1009 can wait until the predetermined time arrives before sending a control signal to the continuous inkjet printer 1002. The predetermined time may be programmed into the external controller 1009 or may appear, for example, in a database (such as a digital calendar) that the external controller 1009 has access to.

[0234] The external controller 1009 can send a control signal to the continuous inkjet printer 1002 based on first receiving a signal from the continuous inkjet printer 1002. That is, if the continuous inkjet printer 1002 determines that a cleaning operation is necessary, the continuous inkjet printer 1002 can send a signal to the external controller 1009 indicating that self-cleaning is necessary. The continuous inkjet printer 1002 can then wait to receive a control signal from the external controller 1009 before performing a self-cleaning operation. Upon receiving the signal from the continuous inkjet printer 1002, the external controller 1009 can wait until an appropriate time before sending the control signal to the continuous inkjet printer 1002. In this way, the external controller 1009 is alerted to the need for cleaning but can select an appropriate time (such as during production line downtime) to allow the continuous inkjet printer 1002 to perform self-cleaning. The continuous inkjet printer 1002 can determine that a cleaning operation is necessary based on a condition being met. The condition can be an estimated time. For example, the expected time may be a predetermined time known to the continuous inkjet printer 1002 at which the continuous inkjet printer 1002 should perform a self-cleaning operation of the self-cleaning printhead 1006. The condition may be a determination that no product has passed through the continuous inkjet printer 1002 within a predetermined time period. For example, the continuous inkjet printer 1002 may have a sensor (or access data from an external sensor) that detects the passage of products as they travel along a conveyor belt. If no product has passed through the continuous inkjet printer 1002 within the predetermined time period, the production line may be assumed to be idle, and the self-cleaning operation of the self-cleaning printhead 1006 may be performed without stopping the production line. The sensor data may be combined with the time data. For example, the condition may be a determination that no product has passed through the continuous inkjet printer 1002 within the predetermined time period and a determination that the current time corresponds to the expected time.

[0235] The condition may include historical data. For example, the historical data may include the time and / or number of prints that have elapsed since the last fault event. For example, if it is determined that the time and / or number of prints that have elapsed since the last fault event has elapsed, the continuous inkjet printer 1002 may determine that the condition has been met. The historical data may include data indicating the mean time between faults. For example, if it is determined that the continuous inkjet printer 1002 is approaching or has reached the mean time before fault, the continuous inkjet printer 1002 may determine that the condition has been met. The historical data may include data indicating marking medium (e.g., ink) usage. For example, if a predetermined amount of marking medium has been used, the continuous inkjet printer 1002 may determine that the condition has been met. The historical data may include data indicating the number of markings and / or individual marking actions (e.g., the number of droplets printed in the case of a continuous inkjet printer) applied to the product. For example, if a predetermined number of markings have been applied, or a predetermined number of individual marking actions have occurred, the continuous inkjet printer 1002 may determine that the condition has been met. The historical data may include data indicating historical environmental data, such as the ambient humidity, temperature, and / or pressure of the environment in which the continuous inkjet printer 1002 operates. The environmental data may be collected over a predetermined period of time in which the continuous inkjet printer 1002 has been operating. If the environmental data satisfies a predetermined condition, such as one or more of humidity, temperature, and / or pressure being above (or below) a specific level for a specific period of time, the continuous inkjet printer 1002 may determine that the condition has been met. The continuous inkjet printer 1002 may have one or more sensors for detecting the environmental conditions, or may obtain the environmental conditions from external sensors.

[0236] The control signal may take any suitable form. For example, the control signal may include an analog or digital signal. The signal may have a signature that can be detected by the continuous inkjet printer 1002, which indicates that a self-cleaning operation is to be performed. Upon receiving the control signal, the processor 1003 causes the continuous inkjet printer 1002 to perform a self-cleaning operation. That is, the processor 1003 controls the continuous inkjet printer 1002 as described above. Figure 2-9The various components of the self-cleaning printhead 1006 are described in order to clean the printhead 1006. Alternatively, the control signal may include computer-readable instructions that are executable by the processor 1003 of the continuous inkjet printer and, when executed, cause the continuous inkjet printer 1002 to perform a self-cleaning operation. The continuous inkjet printer 1002 may continuously monitor signals received from the external controller 1009 and may be configured to take action upon receipt of those signals (such as control signals). In this manner, upon receipt of a control signal from the external controller 1009, the continuous inkjet printer 1002 may take appropriate action. The control signal may be transmitted as an electrical signal using, for example, RS232 or Ethernet. Alternatively, the control signal may be transmitted wirelessly (e.g., using a short-range communication protocol), optically, magnetically, mechanically, hydraulically / pneumatically, or the like.

[0237] In step S2, in response to receiving the control signal, a self-cleaning operation of the self-cleaning printhead 1006 is performed. The self-cleaning operation includes an intrinsic cleaning operation. That is, the self-cleaning operation does not require the use of an external cleaning device. The external cleaning device can be a device separate from the self-cleaning printhead 1006 and / or the continuous inkjet printer 1002. In this manner, the self-cleaning printhead 1006 is cleaned in situ and does not need to be moved from its normal printing position (e.g., the normal position in which the printhead 1006 is positioned when applying markings to a product) to a cleaning position (e.g., a position in which the external cleaning device is positioned, or a position in which the external cleaning device is allowed to access the printhead 1006 for cleaning). For example, the self-cleaning printhead 1006 is not required to be moved away from the surface of the product 1008 on which it is applying markings to allow the external cleaning device to access and clean the space surrounding the self-cleaning printhead 1006. Instead, the self-cleaning printhead 1006 can remain in its normal printing position while it performs its self-cleaning operation.

[0238] The self-cleaning operation may be as above and with respect to Figures 1 to 9 described.

[0239] Once the self-cleaning printhead 1006 has completed its self-cleaning operation, the continuous inkjet printer 1002 can notify the external controller 1009. For example, the continuous inkjet printer 1002 can generate data indicating the completion of the self-cleaning operation and then send this data to the external controller 1009. In this way, the continuous inkjet printer 1002 can notify the external controller 1009 that cleaning is complete, thereby indicating that the continuous inkjet printer 1002 is ready to print again. The continuous inkjet printer 1002 can be configured to automatically begin marking products again after cleaning is complete. That is, when cleaning is complete and the production line 1001 is restarted, the continuous inkjet printer 1002 can begin marking products again as they pass through the printer 1002 on the production line 1001. Alternatively, the continuous inkjet printer 1002 can be configured to wait for another control signal from the external controller 1009 before marking the products 1008, which is configured to cause the continuous inkjet printer 1002 to begin marking the products 1008 on the production line 1001.

[0240] exist Figure 12 An alternative method for cleaning a self-cleaning printhead is depicted in the flow chart shown. Although described in the context of a continuous inkjet printer and a self-cleaning printhead, the method can certainly be applied to industrial printers and self-cleaning marking heads.

[0241] At step S3, sensor data indicating the operation of the self-cleaning print head 1006 is acquired by the continuous inkjet printer 1002. The sensor data may be data output by one or more sensors of the continuous inkjet printer 1002, and it provides data indicating the status of the self-cleaning print head 1006. For example, there may be various sensors for various components of the continuous inkjet printer 1002. These sensors provide information about parameters related to the corresponding components. For example, the printhead 1006 may include nozzles having the following parameters: sensor parameters such as modulation voltage set point, modulation current, frequency, temperature, jet velocity set point, actual velocity, target pressure, temperature compensated target pressure, and actual pressure; phase sensor parameters, including selected phase, phase change rate, profile, and phase threshold; EHT parameters such as voltage, current, trip value, and trip percentage; gutter parameters such as accumulation, time since last cleaning, warning level setting, and ink presence in the gutter; printhead heater parameters such as set temperature, actual temperature, and actuator; printhead cap parameters such as state (open or closed) and time since last removal; state of various printhead valves (open, closed, and time opened or closed); nozzle parameters such as target velocity, drop frequency, print count, run hours, and deflected drops. Thus, one or more sensors of the self-cleaning printhead 1006 can provide data related to the operation of the self-cleaning printhead 1006.

[0242] At step S4, the continuous inkjet printer 1002 determines a service issue associated with the self-cleaning printhead 1006 based on the sensor data. For example, the continuous inkjet printer 1002 can monitor the sensor data and can determine an issue that may affect the normal operation of the self-cleaning printhead 1006. Such a service issue can be, for example, the detection of debris accumulation in or around the gutter of the self-cleaning printhead 1006, or the detection of an EHT trip. For example, a gutter accumulation sensor can be used to determine the accumulation of debris in or around the gutter. Another service issue can be the detection of a phase signal that does not meet a defined set of rules for an extended period of time. The determination of a service issue can indicate that maintenance is required.

[0243] In step S5, the continuous inkjet printer 1002 performs a self-cleaning operation of the print head 1006 in response to the identified maintenance issue. As described above, it may be advantageous to perform the cleaning operation at a specific time, such as when the production line 1001 is stopped. Therefore, the continuous inkjet printer 1002 may, before performing the self-cleaning operation and in response to the identification of the maintenance issue, send data indicating a maintenance issue to the external controller 1009. The continuous inkjet printer 1002 may then wait until it receives a control signal as described above before performing the self-cleaning operation. Upon receiving the data indicating the maintenance issue, the external controller 1009 determines an appropriate time to send the control signal to the continuous inkjet printer 1002, as described above. This allows the self-cleaning operation to be performed at an appropriate time, taking into account the overall operation of the production line 1001.

[0244] Additionally or alternatively, the continuous inkjet printer 1002 may include a first self-cleaning printhead and a second self-cleaning printhead, wherein the second self-cleaning printhead can operate in place of the first self-cleaning printhead while the first self-cleaning printhead is being cleaned. For example, the second printhead can be considered a backup printhead that is not used during normal operation and is only used when the first printhead is being cleaned (or is otherwise inactive). For example, upon receiving the control signal described above, the continuous inkjet printer 1002 can stop using the first self-cleaning printhead to mark products 1008 on the production line 1001, begin cleaning the first self-cleaning printhead, and begin operating the second self-cleaning printhead to mark products 1008 in place of the first self-cleaning printhead. In examples where the continuous inkjet printer 1002 includes multiple printheads that can be used in place of each other, the timing of the control signal may not be critical. That is, if the second self-cleaning printhead can be used in place of the first self-cleaning printhead, the production line does not need to be stopped to perform the cleaning. In such an example, the external controller 1009 may then send a control signal to the continuous inkjet printer 1002 at any suitable time, such as a time corresponding to a predetermined elapsed time since a previous cleaning operation.

[0245] Figure 13 A computing device 1040 configured to perform the methods disclosed herein is shown. The external controller 1009 and / or the continuous inkjet printer 1002 may include the computing device 1040. The computing device 1040 includes a processor 1040a configured to read and execute instructions stored in a volatile memory 1040b, which is in the form of random access memory. The volatile memory 1040b stores instructions for execution by the processor 1040a and data used by those instructions.

[0246] Computing device 1040 also includes non-volatile storage in the form of a hard drive 1040c. Computing device 1040 also includes an I / O interface 1040d, to which data capture and peripheral devices used in conjunction with computing device 1040 are optionally connected. In the example shown, a display 1040e is connected to I / O interface 1040d to display output from computing device 1040. Display 1040e can be provided locally to external controller 1009 (e.g., as a screen) or remote from external controller 1009. For example, a display associated with a separate device (e.g., a mobile computing device) can serve as the display for external controller 1009. Additionally or alternatively, a touchscreen associated with display 1040e can operate as a user input device to allow a user to interact with computing device 1040. Alternatively or additionally, separate input devices, such as a mouse and / or keyboard, can also be connected to I / O interface 1040d. The network interface 1040f allows the computing device 1040 to connect to an appropriate computer network in order to receive data from and send data to other computing devices (e.g., the continuous inkjet printer 1002). The processor 1040a, volatile memory 1040b, hard drive 1040c, I / O interface 1040d, and network interface 1040f are connected together via a bus 1040g. The computing device 1040 can be connected to an external computer / server via the network interface 1040f.

[0247] Although the present disclosure has been described in terms of the preferred embodiments described above, it should be understood that these embodiments are illustrative only and that the claims are not limited to those embodiments. Those skilled in the art will be able to make modifications and substitutions in light of this disclosure, which modifications and substitutions are considered to fall within the scope of the appended claims. Each feature disclosed or shown in this specification may be incorporated into the present disclosure, either alone or in any appropriate combination with any other feature disclosed or shown herein.

Claims

1. A computer-implemented method for cleaning a self-cleaning marking head of an industrial printer, the method comprising: receiving a control signal by the industrial printer and from an external controller; The industrial printer performs a self-cleaning operation of the self-cleaning marking head in response to receiving the control signal. 2 . The computer-implemented method of claim 1 , wherein the self-cleaning operation comprises an intrinsic cleaning operation.

3. The computer-implemented method of claim 1 or 2, wherein the self-cleaning operation does not include the use of an external cleaning device.

4. The computer-implemented method of any preceding claim, wherein the industrial printer is a continuous inkjet printer and the self-cleaning marking head is a self-cleaning print head.

5. The computer-implemented method of claim 4 , wherein the self-cleaning operation comprises driving a sealing mechanism of the self-cleaning printhead from a first configuration in which a chamber of the self-cleaning printhead is in communication with the atmosphere at least via an ink orifice to a second configuration in which the chamber is sealed. 6 . The computer-implemented method of claim 5 , wherein the self-cleaning operation further comprises directing a cleaning fluid into the chamber to clean the chamber.

7. The computer-implemented method of any one of claims 5 or 6, wherein the sealing mechanism comprises a rotatable body rotatable about a rotational axis between the first configuration and the second configuration, and wherein, Actuating the sealing mechanism of the self-cleaning printhead from the first configuration to the second configuration comprises: The rotatable body of the sealing mechanism of the self-cleaning printhead is rotated from the first configuration to the second configuration in which the chamber is sealed by the rotatable body.

8. A computer-implemented method according to any one of claims 5 to 7, when dependent on claim 6, wherein the chamber comprises a plurality of ports, the method further comprising: selecting, by the continuous inkjet printer, a port of the chamber as a fill port and a port of the chamber as a drain port based on the orientation of the self-cleaning print head; wherein directing the cleaning fluid into the chamber to clean the chamber comprises directing a flow of cleaning fluid through the fill port into the cleaning chamber to clean the cleaning chamber; as well as The cleaning fluid is discharged from the cleaning chamber through the discharge port to empty the cleaning chamber.

9. A computer-implemented method according to any preceding claim, the control signal being sent based on a predetermined condition being satisfied.

10. The computer-implemented method of claim 9, wherein the predetermined condition is a status of a production line on which the industrial printer is operating.

11. The computer-implemented method of claim 10, wherein the status comprises a stop on the production line on which the industrial printer is operating.

12. The computer-implemented method of claim 9, wherein the predetermined condition comprises a predetermined time.

13. The computer-implemented method of any preceding claim, further comprising: The control signal is sent by the external controller to the industrial printer.

14. The computer-implemented method of any preceding claim, further comprising: determining, by the industrial printer, completion of the self-cleaning operation; Data indicating completion of the self-cleaning operation is sent by the industrial printer to the external controller.

15. A computer-implemented method for cleaning a self-cleaning marking head of an industrial printer, the method comprising: acquiring, by the industrial printer, sensor data indicative of operation of the self-cleaning marking head; determining, by the industrial printer, a maintenance issue associated with the self-cleaning marking head based on the sensor data; A self-cleaning operation of the self-cleaning marking head is performed by the industrial printer in response to the determined maintenance issue.

16. The computer-implemented method of claim 15, wherein the industrial printer is a continuous inkjet printer and the self-cleaning marking head is a self-cleaning print head.

17. A computer-implemented method according to claim 16, wherein the self-cleaning operation includes driving a sealing mechanism of the self-cleaning print head from a first configuration to a second configuration, wherein the first configuration has a chamber of the self-cleaning print head connected to the atmosphere via at least an ink hole, and wherein the chamber is sealed.

18. The computer-implemented method of claim 17, wherein the self-cleaning operation further comprises directing a cleaning fluid into the chamber to clean the chamber.

19. The computer-implemented method of any one of claims 17 or 18, wherein: The sealing mechanism comprises a rotatable body rotatable about a rotation axis between the first configuration and the second configuration, and wherein driving the sealing mechanism of the self-cleaning printhead from the first configuration to the second configuration comprises: The rotatable body of the sealing mechanism of the self-cleaning printhead is rotated from the first configuration to the second configuration in which the chamber is sealed by the rotatable body.

20. A computer-implemented method according to any one of claims 17 to 19, when dependent on claim 18, wherein the chamber comprises a plurality of ports, the method further comprising: selecting, by the continuous inkjet printer, a port of the chamber as a fill port and a port of the chamber as a drain port based on the orientation of the self-cleaning print head; wherein directing the cleaning fluid into the chamber to clean the chamber comprises directing a flow of cleaning fluid through the fill port into the cleaning chamber to clean the cleaning chamber; as well as The cleaning fluid is discharged from the cleaning chamber through the discharge port to empty the cleaning chamber.

21. The computer-implemented method of any one of claims 15 to 20, wherein the industrial printer comprises a second marking head, and wherein, While the mentioned first self-cleaning marking head is undergoing said self-cleaning operation, the second marking head is driven to mark one or more products.

22. The computer-implemented method of claim 21 , further comprising: Completion of the self-cleaning operation is determined by the industrial printer, and in response, the first self-cleaning marking head is driven to print on the one or more products in place of the second marking head.

23. The computer implemented method of claim 21 or 22, wherein the second marking head is a second self-cleaning marking head.

24. The computer-implemented method of any one of claims 15 to 23, further comprising: sending, by the industrial printer and in response to the determination of the maintenance issue, data indicative of the maintenance issue to an external controller; as well as A control signal is received by the industrial printer and from the external controller, the control signal being configured to cause the industrial printer to perform the cleaning operation, wherein performing the cleaning operation by the industrial printer in response to the maintenance issue includes performing the cleaning operation by the industrial printer in response to the control signal.

25. The computer-implemented method of claim 24, further comprising: The control signal is sent by the external controller to the industrial printer.

26. The computer-implemented method of claim 25, wherein sending the control signal by the external controller comprises: The external controller determines that a predetermined condition is satisfied, and transmits the control signal when it is determined that the predetermined condition is satisfied.

27. The computer-implemented method of claim 26, wherein the predetermined condition is a status of a production line on which the industrial printer is operating.

28. The computer-implemented method of claim 27, wherein the status comprises a stop on the production line on which the industrial printer is operating.

29. The computer-implemented method of any one of claims 15 to 28, further comprising: determining, by the industrial printer, completion of the self-cleaning operation; Data indicating completion of the self-cleaning operation is sent by the industrial printer to the external controller.

30. A computer-implemented method for operating an industrial printer, the industrial printer comprising a first marking head and a second marking head, the industrial printer operating on a production line and marking products on the production line using the first marking head, the computer-implemented method comprising: determining a maintenance issue associated with the first marking head; In response to determining the maintenance issue, performing a cleaning operation on the first marking head; In response to the executing, the second marking head is driven to replace the first marking head to mark products on the production line.

31. The computer implemented method of claim 30, wherein the first marking head and / or the second marking head is a self-cleaning marking head and the cleaning operation is a self-cleaning operation.

32. The computer-implemented method of any one of claims 30 or 31, wherein the industrial printer is a continuous inkjet printer, and the first and second self-cleaning marking heads are first and second self-cleaning print heads.

33. A computer-implemented method according to claim 32, wherein the self-cleaning operation includes driving a sealing mechanism of the first self-cleaning print head from a first configuration to a second configuration, wherein the chamber of the first self-cleaning print head is connected to the atmosphere at least via the ink hole, and in the second configuration, the chamber is sealed.

34. The computer-implemented method of claim 33, wherein the self-cleaning operation further comprises directing a cleaning fluid into the chamber to clean the chamber.

35. The computer-implemented method of any one of claims 33 or 34, wherein the sealing mechanism comprises a rotatable body rotatable about a rotational axis between the first configuration and the second configuration, and wherein, Actuating the sealing mechanism of the first self-cleaning print head from the first configuration to the second configuration includes: The rotatable body of the sealing mechanism of the first self-cleaning printhead is rotated from the first configuration to the second configuration in which the chamber is sealed by the rotatable body.

36. A computer-implemented method according to any one of claims 33 to 35, when dependent on claim 34, wherein the chamber comprises a plurality of ports, the method further comprising: selecting, by the continuous inkjet printer, a port of the chamber as a fill port and a port of the chamber as a drain port based on the orientation of the first self-cleaning print head; wherein directing the cleaning fluid into the chamber to clean the chamber comprises directing a flow of cleaning fluid through the fill port into the cleaning chamber to clean the cleaning chamber; as well as The cleaning fluid is discharged from the cleaning chamber through the discharge port to empty the cleaning chamber.

37. The computer-implemented method of any one of claims 30 to 36, wherein when the first marking head is being used to mark a product, the second marking head is not being used to mark a product.

38. A system comprising: Industrial printers; an external controller coupled to the industrial printer; A system configured to perform a method according to any preceding claim.

39. A computer-readable medium storing computer-readable instructions which, when executed by one or more processors, cause the one or more processors to perform the method of any one of claims 1 to 37.

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