Ink-on-demand system and method for card processing system using tankless recirculation

Abstract

A DOD inking system and method are described herein for supplying ink in a DOD card printing system of a card processing system for DOD printing on plastic cards. The inking system is configured to recirculate ink without using a recirculation tank independent of an ink source. The ink may be recirculated back to the ink source, or, in the absence of an ink source, the ink may be recirculated from a return ink collection tank to an ink supply ink collection tank.

Description

Technical Field

[0001] The present disclosure relates to a card processing system for drop-on-demand (DOD) printing on plastic cards, including but not limited to financial cards (e.g., credit cards, debit cards, etc.), driver's licenses, national identification cards, business cards, gift cards, and other plastic cards. Background Art

[0002] In DOD printing, ink is ejected from one or more nozzles of a print head by energizing selected ones of the one or more nozzles from which the ink is to be ejected. Performing DOD printing on plastic cards in a card processing system presents a unique challenge. Printing on plastic cards must be durable, long-lasting, and of very high quality. Furthermore, printing may vary from monochrome printing using a single color of ink to color printing using multiple colors of ink (e.g., cyan, magenta, yellow, black, and white). Furthermore, in a card processing system employing DOD printing, card throughput (i.e., the number of cards printed per unit time) is an important factor, and much effort is made to maximize card throughput. Furthermore, printing on plastic cards may and often does vary from card to card. Summary of the invention

[0003] Described herein are DOD inking systems and methods for use in a DOD card printing system of a card processing system to provide ink for DOD printing on plastic cards bearing unique personalized data of a predetermined cardholder and / or bearing other card information. Examples of plastic cards may include, but are not limited to, financial cards (e.g., credit cards, debit cards, etc.), driver's licenses, national identification cards, business cards, gift cards, and other plastic cards.

[0004] In one embodiment described herein, the DOD inking system is configured to recirculate ink without using a recirculation tank that is independent of the ink source. In one embodiment, the ink source may be a container that holds the ink when it is purchased / supplied and is disposed of after use. In another embodiment, the ink source may be any form of disposable container that is disposed of after use. The recirculation tank or bulk tank is a fixed component in the system that is designed to be filled with ink from the ink source and is not easily removed and will not be disposed of after use when the ink is exhausted. Recirculation is useful for inks that require recirculation, which can improve the final performance when the ink is applied to a plastic card. The ink may be an ink containing particulate matter, and the recirculation keeps the particles well dispersed in the ink. Examples of inks with particulate matter include, but are not limited to, white inks and inks known as spot colors in the card printing industry, including gold, silver, and red inks. The ink may also be an ink (with or without particulate matter, and may be a spot color or non-spot color ink) that is recirculated to remove gas from it.

[0005] The card processing system described herein can be any card processing system capable of processing plastic cards by printing on the cards using a DOD card printing system, wherein the DOD card printing system has one or more DOD print heads, such as piezoelectric print heads, and performs one or more of the following operations: reading data from and / or writing data to a magnetic stripe on a card, programming an integrated circuit chip on a card, embossing characters on a card, stamping characters on a card, laminating a card, laser marking a card using a laser that performs laser processing, applying an outer coating to a portion of the surface or the entire surface of a card, inspecting the quality of personalization / processing applied to a card, applying anti-counterfeiting features (such as a holographic foil) to a card, and performing other card processing operations.

[0006] The DOD card printing system used in the card processing system may have a single DOD print head or multiple DOD print heads. The DOD print head may be a piezoelectric print head. The DOD card printing system may perform monochrome printing or multi-color printing. In one example of multi-color printing, five DOD print heads may be provided, each having multiple nozzles. Each print head may be designated to print a specific color of ink, such as cyan, magenta, yellow, black and white (CMYKW). The DOD card printing system may print using any suitable ink (or other material) used in DOD printing and is suitable for use with the types of plastic cards described herein. For example, the ink may be an ultraviolet (UV) radiation curable ink.

[0007] In one embodiment, a drop-on-demand card printing system may include a drop-on-demand printhead having an ink inlet and an ink outlet, and an ink delivery system connected to the drop-on-demand printhead. The ink delivery system may include a first ink collection tank fluidly connected to the ink inlet and a second ink collection tank fluidly connected to the ink outlet, and an ink recirculation system defining an ink recirculation path configured to allow ink to be recirculated through the first ink collection tank and the second ink collection tank. The ink recirculation system is devoid of an ink supply tank, whereby the recirculated ink is not directed to the ink supply tank after leaving the second ink collection tank and before entering the first ink collection tank. The drop-on-demand card printing system may also include a vacuum system fluidly connected to the first and second ink collection tanks and applying a vacuum to the drop-on-demand printhead.

[0008] In another embodiment, a method of operating a drop-on-demand card printing system of a card processing system is described. The drop-on-demand card printing system includes an ink delivery system connected to a drop-on-demand printhead, wherein the ink delivery system has a first ink collection tank fluidly connected to an ink inlet and a second ink collection tank fluidly connected to an ink outlet. The method includes recirculating ink through the drop-on-demand printhead through the first ink collection tank and the second ink collection tank using an ink recirculation system defining an ink recirculation path, the ink recirculation path being configured to allow ink to be recirculated through the first ink collection tank and the second ink collection tank, without an ink supply tank in the ink recirculation path, whereby the recirculated ink is not directed into the ink supply tank after leaving the second ink collection tank and before entering the first ink collection tank.

[0009] In another embodiment, a method of operating a drop-on-demand card printing system of a card processing system is described. The drop-on-demand card printing system may include an ink supply system connected to a drop-on-demand ink printhead, wherein the ink supply system has a first ink collection tank fluidly connected to an ink inlet, a second ink collection tank fluidly connected to an ink outlet, and an ink supply bottle. The method includes pumping ink directly from the ink supply bottle into the first ink collection tank when ink needs to be supplied to the first ink collection tank, and pumping ink from the second ink collection tank directly into the ink supply bottle when ink needs to be removed from the second ink collection tank, thereby causing mixing of ink in the ink supply bottle.

[0010] In another embodiment, a method of operating a drop-on-demand card printing system of a card processing system is described. The drop-on-demand card printing system may include an ink delivery system connected to a drop-on-demand printhead, wherein the ink delivery system has a first ink collection tank fluidly connected to an ink inlet, a second ink collection tank fluidly connected to an ink outlet, and a mounting location for mounting an ink supply bottle. The method includes pumping ink from the second ink collection tank directly back to the first ink collection tank when there is no ink supply bottle at the mounting location and ink needs to be removed from the second ink collection tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 One embodiment of the card processing system described herein is shown.

[0012] Figure 2 One embodiment of a DOD card printing system that may be used in conjunction with the card processing system described herein is shown.

[0013] Figure 3 Another embodiment of a DOD card printing system that may be used in conjunction with the card processing system described herein is shown.

[0014] Figure 4 Another embodiment of a DOD card printing system that may be used in conjunction with the card processing system described herein is shown. DETAILED DESCRIPTION

[0015] Figure 1 An example of a card processing system 10 is shown, with which the DOD card printing system described herein may be used in conjunction. The DOD card printing system may also be referred to as a DOD printing system. The system 10 is configured to process cards by at least printing on the cards using at least one DOD card printing system 12 included in the system 10. In addition to printing via the DOD card printing system 12, the system 10 may also include at least one other card processing capability. For example, the additional card processing may include a magnetic stripe reading / writing system 14 configured to read data from and / or write data to a magnetic stripe on a card, and / or an integrated circuit chip programming system 16 configured to program and / or read data from an integrated circuit chip on a card. When the DOD card printing system 12 prints using ultraviolet (UV) curable ink, a UV curing station 18 may also be provided. The construction and operation of the systems 14, 16, 18 are well known in the art. For example, magnetic stripe read / write systems and integrated circuit chip programming systems are disclosed in U.S. Pat. No. 6,902,107 and U.S. Pat. No. 6,695,205 and can be found in the MX series central issuance systems manufactured by Entrust Corporation of Shakopee, Minnesota, U.S.A. An example of an ultraviolet radiation application device in a card printing system is the MX8100 manufactured by Entrust Corporation of Shakopee, Minnesota, U.S.A. TM Card issuance system.

[0016] Cards to be processed in the card processing system 10 include, but are not limited to, plastic cards that carry unique personalized data of the intended cardholder and / or carry other card information. Examples of plastic cards may include, but are not limited to, financial cards (e.g., credit cards, debit cards, etc.), driver's licenses, national identification cards, business cards, gift cards, and other plastic cards.

[0017] In some embodiments, the DOD card printing system 12 described herein may be used to print on substrates other than plastic cards (eg, paper substrates), in which case the DOD card printing system 12 may be referred to as a DOD printing system.

[0018] exist Figure 1 In the illustrated system 10, there is a card input device 20 configured to accommodate a plurality of cards to be processed. Cards are fed one by one from the card input device 20 to the rest of the system 10, where each card is processed individually. The processed cards are ultimately transported to a card output device 22 configured to accommodate a plurality of processed cards.

[0019] The operation of each system 12, 14, 16, 18, 20, 22 is controlled by one or more controllers 24. Alternatively, each of the systems 12, 14, 16, 18, 20, 22 or selected ones of the systems 12, 14, 16, 18, 20, 22 may have its own dedicated controller.

[0020] Cards may be fed through the card processing system 10 using any suitable mechanical card transport mechanism known in the art for transporting cards within the card processing system 10. Examples of card transport mechanisms that may be used are known in the art and include, but are not limited to, transport rollers, transport belts (with and / or without tabs), vacuum transport mechanisms, transport carts, and the like, and combinations thereof. Card transport mechanisms are well known in the art, including those disclosed in U.S. Patents 6,902,107, 5,837,991, 6,131,817, and 4,995,501, and U.S. Published Application 2007 / 0187870, all of which are incorporated herein by reference in their entirety. The types of card transport mechanisms that may be used, as well as the construction and operation of such card transport mechanisms, are readily understood by those of ordinary skill in the art.

[0021] Figure 1 The illustrated card processing system 10 is a system that may be referred to as a central issue card processing system. In a central issue card processing system, a card input device 20 and a card output device 22 are typically located at opposite ends of the system 10, and a card processing mechanism (e.g. Figure 1The system 12, 14, 16, 18 in FIG. 1 is located between the card input device 20 and the card output device 22. Central issue card processing systems are typically used for high volume card processing, often using multiple processing stations or modules to process multiple cards simultaneously to reduce the total processing time for each card. Examples of central issue card processing systems include the MX series central issue systems produced by Entrust Corporation of Shakopee, Minnesota, USA. Other examples of central issue systems are disclosed in U.S. Patents 4,825,054, 5,266,781, 6,783,067, and 6,902,107, all of which are incorporated herein by reference in their entirety. In one example, the card processing system 10 (and systems 12, 14, 16, 18 therein) may process cards at a rate of at least about 500 cards / hour, or at least about 1000 cards / hour, or at least about 1500 cards / hour, or at least about 2000 cards / hour, or at least about 2500 cards / hour, or at least about 3500 cards / hour, or at least about 4000 cards / hour.

[0022] exist Figure 1 In the embodiment of the present invention, the systems 12, 14, 16, 18 may be described as being located downstream of the card input device 20 and as being located between the card input device 20 and the card output device 22. The order or arrangement of the systems 12, 14, 16, 18 relative to each other and relative to the card input device 20 may vary. Figure 1 in the order shown.

[0023] System 10 may include Figure 1 Additional card processing systems, not shown, are well known in the art of card processing and may also be located between the card input device 20 and the card output device 22. For example, the system 10 may include a card imprinting system configured to imprint characters on a card; a stamping system configured to punch characters on a card; a laminating system configured to laminate a card; a laser system that uses a laser to perform laser processing (e.g., laser marking) on ​​a card; an overcoating station configured to apply an overcoat to a portion of or the entire surface of a card; a quality control station configured to check the quality of personalization / processing applied to a card; a security station configured to apply security features (e.g., holographic foil) to a card; and other card processing operations. The additional card processing systems may be located anywhere in the system 10, such as between the UV curing station 18 and the card output device 22.

[0024] Figure 2-4A non-limiting example of a DOD card printing system 12 is shown. Other examples are possible. The overall construction and operation of a DOD card printing system is well known in the art. An example of a conventional DOD card printing system may be found in the MX8100 manufactured by Entrust Corporation of Shakopee, Minnesota, USA. TM Found in the card issuance system.

[0025] Figure 2-4 Each of the DOD card printing systems 12 includes at least one DOD printhead 30, an ink delivery system 32 connected to the DOD printhead 30, and a vacuum system 34 for applying vacuum to the DOD printhead 30. In addition, each system 12 may include a cap tray 36 that is selectively positionable below the DOD printhead 30 and configured to move between a covering position and a non-covering position directly below the DOD printhead 30 during a printing operation. The cap tray 36 is also configured to collect ink that may be discharged from the DOD printhead 30 when it is in the covering position.

[0026] The printing performed by the DOD card printing system 12 can be monochrome printing using a single color, or multicolor printing using two or more colors. If multiple print heads are used, the print heads are typically arranged side by side to print on the surface of the card in sequence as the card is fed past the print heads (e.g., under the print heads). The DOD print head 30 can print using any suitable ink or coating (e.g., varnish) used in DOD printing and suitable for the type of plastic card described herein. For example, the ink can be an ultraviolet curable ink, a heat curable ink that can be cured by applying heat to the heat curable ink, or other ink or other material that can be deposited by the DOD print head. An example of a DOD printer that prints using ultraviolet curable ink is the MX8100 manufactured by Entrust Corporation of Shakopee, Minnesota, USA. TM Card issuance system. Each DOD printhead 30 can print a specific color of ink. The term "fluid" can be used to refer to any material that can be applied to the surface of a card by a DOD printhead 30, such as ink or a coating material.

[0027] Generally, each DOD printhead 30 includes a bottom surface that faces downward toward the plastic card to be printed on. A nozzle plate is provided on a portion of the bottom surface, and ink is ejected through the nozzle plate. The nozzle plate includes a plurality of openings, each of which is associated with an inkjet nozzle of the printhead. Each DOD printhead 30 can be a piezoelectric printhead that requires electrical energy to activate the printhead and eject ink. The overall mechanical construction and operation of a piezoelectric printhead are well known in the art.

[0028] Please refer to Figure 2 , a first embodiment of the DOD card printing system 12 will be described below. Figure 2 In the embodiment of the present invention, the system 12 includes a single print head 30. The system 12 is also provided with a recirculation system as part of the ink delivery system 32, which recirculates the ink (or other material) ejected from the print head 30. Figure 2 With reference to the concepts shown in the system 12 in FIG. 1 , the material discharged by the single print head 30 will be described and illustrated as white ink. As described above, the white ink used in DOD card printing generally contains particulate matter, and therefore the white ink is recirculated to keep the particulate matter well dispersed in the white ink. However, the material discharged by the print head 30 is not limited to white ink, and can be any material that facilitates the recycling of the material, including but not limited to spot colors (e.g., gold, silver, and red inks), inks that are recirculated to remove gases from the ink, coating materials, and other fluids that can be applied to the card surface by the DOD print head 30.

[0029] The print head 30 includes an inlet 40 connected to the supply side of the ink delivery system 32 and an outlet 42 connected to the recirculation side of the ink delivery system 32. The outlet 42 is different from the discharge nozzle that discharges ink during the printing operation and is generally located at the bottom of the print head 30. On the supply side, the inlet 40 is fluidly connected to a first ink collection tank 44, which contains a certain amount of white ink and constantly supplies white ink to the print head 30. The supply side also includes an ink supply pump 48 that pumps white ink into the ink collection tank 44, a filter 50 that filters the white ink between the ink supply pump 48 and the ink collection tank 44, and a white ink supply bottle 52 that contains a white ink supply source. The ink supply pump 48 is described as a variable displacement pump. However, the ink supply pump 48 can have any configuration suitable for the pump to perform the function of the ink supply pump 48. In addition, a one-way check valve 46 is provided between the ink supply pump 48 and the filter 50, which allows the white ink to flow to the ink collection tank 44, but prevents the white ink from flowing back to the ink supply pump 48. In some embodiments, the check valve 46 and the ink supply pump 48 may be combined into a single component. In addition, a solenoid valve 51 is provided between the filter 50 and the ink collection tank 44, which can be used to discharge ink from the system through a waste liquid collection system 90 discussed further below.

[0030] Please continue to refer to Figure 2, on the recirculation side, the outlet 42 is fluidly connected to a second ink collecting tank 54, which also contains a certain amount of white ink. A recirculation line 55 extends from the second ink collecting tank 54 to a return pump 58 (also referred to as a recirculation pump), and from the return pump 58 to a one-way check valve 56 (also referred to as a recirculation check valve). The recirculation line 55 then extends from the check valve 56 to a supply line connected to the inlet of the ink supply pump 48. The one-way check valve 56 allows white ink to flow out of the return pump 58, but prevents white ink from flowing back to the return pump 58 and the ink collecting tank 54. The return pump 58 is shown as a variable displacement pump. However, the return pump 58 may have any configuration suitable for enabling the pump to perform the function of the return pump 58. In some embodiments, the check valve 56 may be disposed in the recirculation line 55 between the return pump 58 and the ink collecting tank 54.

[0031] A controller 60 is provided, which is connected to the solenoid valve 51 to control the operation of the solenoid valve 51. The controller 60 (or a separate controller) may also be connected to other controllable valves described herein. The controller 60 (or a separate controller) may also be connected to the pump described herein to control the operation of the pump. The controller 60 may be independent of Figure 1 The controller 24 in the embodiment may also be the same controller as the controller 24.

[0032] An ink level sensor 62, such as a float sensor, may be provided in the ink collection tank 54 to sense the ink level in the ink collection tank 54, and the sensor 62 provides the ink level reading to the controller 60. In addition, an ink level sensor 64, such as a float sensor, may be provided in the ink collection tank 44 to sense the ink level in the ink collection tank 44, and the sensor 64 provides the ink level reading to the controller 60. In operation, one or more ink level readings in the ink collection tanks 44, 54 may be used to determine when to recirculate the ink. For example, the ink level reading from the ink level sensor 62 in the ink collection tank 54 may be used to control the operation of the valve 51 and the pumps 48, 58 to determine when to recirculate.

[0033] In this specification and claims, the ink supply bottle 52 is not considered to be an ink supply tank. On the contrary, the recycling system and its recycling path do not have an ink supply tank. In one embodiment, the ink supply bottle can be a container that holds ink when the ink is purchased / supplied and is discarded after use. In another embodiment, the ink supply bottle can be any form of disposable container that is discarded after use. The ink supply tank (also called a recycling tank or a large capacity tank) is a fixed component in the system, which is designed to be filled with ink from the ink source and is not easily removed and will not be discarded after use when the ink is exhausted.

[0034] exist Figure 2In the illustrated embodiment, the ink supply bottle 52 includes a quick-disconnect fluid fitting 53 connected to the recirculation flow path between the return pump 58 and the ink supply pump 48. In use, the ink supply bottle 52 can be mounted vertically with the quick-disconnect fluid fitting 53 at the lowest point, and when the ink supply bottle 52 is in the recirculation flow path, ink can be drawn from the bottle and returned to the bottle 52 via the quick-disconnect fluid fitting 53. Since particles in the ink will settle over time, recirculating the ink back to the bottle 52 at the lowest point will cause the particles to mix and return to the ink in the bottle 52.

[0035] When the ink supply bottle 52 is not present, ink is recirculated from the ink collection tank 54 to the ink collection tank 44. In particular, when the ink supply bottle 52 is removed, the quick-disconnect fluid fitting 53 is closed, and the recirculated ink flows from the return pump 58 to the ink supply pump 48, and from the ink supply pump 48 into the ink collection tank 44. The recirculated ink may be pumped from the ink collection tank 54 to the ink collection tank 44 using either one of the pumps 48, 58 or both pumps 48, 58 operating simultaneously. The pumps 48, 58 may be configured as "free-flow" pumps that allow ink to flow therethrough when in a closed state.

[0036] exist Figure 2 In the illustrated system 12, ink flows from and returns to the ink supply bottle 52 through the same port, which may be referred to as an input / output port. Figure 3 In an alternative configuration of the system 12 shown, the ink supply bottle 52 may have a dual-port design, with one port 66 for removing ink from the bottle 52 and another port 68 for returning ink to the bottle 52. In one embodiment, the port 66 and the port 68 may be located at the same end of the bottle 52, for example, both ports 66 and 68 may be located at the bottom of the bottle 52.

[0037] Please go back Figure 2 , the vacuum system 34 is of conventional construction and need not be described in detail. The vacuum system 34 is configured to apply a vacuum to the nozzles of the print head 30 to form a desired meniscus on the ink in the nozzles. The vacuum system 34 includes a pressure damping vessel 70 (or pressure damper vessel) connected to a vacuum pump 72. The pressure damping vessel 70 has a slow leak device to dissipate excessive vacuum. More details about the vacuum system 34 can be found in U.S. Published Application No. 2020 / 0039228, the entire contents of which are incorporated herein by reference.

[0038] The vacuum line 74 extends between the ink collecting tank 44 and the ink collecting tank 54, and a valve 82, such as a solenoid valve, is provided in the vacuum line 74. The valve 82 is used to isolate the ink collecting tank 54 from the vacuum system 34, which is required in certain maintenance procedures, such as automatic filling, automatic draining, cleaning, etc. More information about automatic filling, automatic draining, cleaning and other maintenance procedures is disclosed in U.S. Published Application No. 2019 / 0344565 and U.S. Published Application No. 2020 / 0039228, the entire contents of which are incorporated herein by reference.

[0039] The waste collection system 90 is connected to the cap tray 36 to collect ink that may be discharged into the cap tray 36. The waste collection system 90 includes a waste manifold 92 that is fluidly connected to the cap tray 36 via a fluid line, and a waste pump 94 is provided in the fluid line, which pumps waste ink from the cap tray 36 into the manifold 92. The waste collection system 90 also includes a system drain line 100 extending from the valve 51 to the waste manifold 92. A system drain pump 102 is provided in the drain line 100. The pump 102 can be used to empty the entire ink system, including but not limited to the print head 30, the ink collection tanks 44, 54, the filter 50, and the ink supply bottle 52. The pump 58 can be operated simultaneously with the pump 102 (but at a lower flow rate) to empty the system.

[0040] In addition, the waste liquid collection system 90 may include a waste liquid collection container 96, into which waste ink from the waste liquid collection pipe 92 may be collected. The waste liquid collection container 96 may be connected to the system using a quick-connect fitting to simplify installation and removal of the container 96. However, one consequence of this connection is that pressure may accumulate if the user does not install the container 96 into the quick-connect fitting. To address this issue, a pressure switch 98 is provided that detects pressure accumulation caused by forgetting to connect the waste liquid collection container 96. Once a certain pressure is reached, the pressure switch 98 sends a signal to the controller 60 to warn the user of the pressure increase and / or remind the user to install the waste liquid collection container 96.

[0041] exist Figure 2 and 3When the system 12 in FIG. 1 is in operation, assuming that there is an ink supply bottle 52, if the ink collecting tank 44 is empty or needs to be replenished with ink, the ink supply pump 48 is operated to draw ink directly from the ink supply bottle 52 to fill the ink collecting tank 44. When the ink collecting tank 54 becomes full, the return pump 58 is operated to pump ink from the ink collecting tank 54 directly back to the ink supply bottle 52. The check valves 46, 56 control the direction of ink flow. The spring pressure acting on the check valves 46, 56 causes the check valves 46 to force the returned ink to flow into the ink supply bottle 52 when the return pump 58 is operated. When the ink supply pump 48 is operated, the check valve 56 forces ink to be drawn from the ink supply bottle 52 instead of from the ink collecting tank 54. When the bottle 52 is removed, the pressure increases, and the springs of the check valves 46, 56 allow the valves 46, 56 to open to allow ink to flow directly from the ink collecting tank 54 to the ink collecting tank 44 (regardless of whether one or both of the pumps 48, 58 are in operation). The return of ink to the ink supply bottle 52 causes the mixing of the ink in the ink supply bottle 52. This mixing can be referred to as global mixing or in-bottle mixing. By controlling the speed and / or size of the return pump 58, the mixing or agitation of the ink can be changed, for example, increased or decreased.

[0042] When the ink supply bottle 52 is removed, such as when a user installs a new ink supply bottle, dead pressure is generated at the location where the quick-disconnect fluid fitting is suddenly closed. In this case, if the return pump 58 is working, the pressure of the returning ink is sufficient to overcome the check valve 46 and achieve "local" recirculation by recirculating the ink in the system, such as from the ink collection tank 54 to the ink collection tank 44, and from the ink collection tank 44 to the ink collection tank 54 via the printhead 30. This may be referred to as local mixing or out-of-bottle mixing.

[0043] In the case of partial recirculation, when the ink supply bottle 52 is not present, the ink must be recirculated directly from the ink collection tank 54 to the ink collection tank 44. Therefore, even if the ink level sensor 64 indicates that the ink collection tank 44 is full, the ink collection tank 44 must be configured to accommodate the recirculated ink from the ink collection tank 54. Figure 2 and Figure 3 In the example shown, in one embodiment, assuming that the ink level sensor 64 is a float switch, a large margin is provided in the ink collection tank 44, which allows the float switch to continue to rise even after the float switch indicates that the ink collection tank 44 has reached its nominal full capacity level. Therefore, the ink collection tank 44 has capacity to receive ink from the ink collection tank 54, allowing the ink collection tank 44 to be filled to more than its nominal full capacity level. Without this additional capacity of the ink collection tank 44, the ink collection tank 44 may overflow into the vacuum system 34 when ink is recirculated from the ink collection tank 54 to the ink collection tank 44.

[0044] In some embodiments, the ink supply bottle 52 may be provided with a radio frequency identification (RFID) element. The RFID element may have data stored thereon, such as an estimate of the amount of ink remaining in the ink supply bottle 52. During use, as ink is supplied from the ink supply bottle 52 or as ink is returned to the ink supply bottle 52, the remaining ink data may be updated. Other data that may be stored on the RFID element may include, but is not limited to, the type of ink, the color of the ink, the manufacturer of the ink, a "birth date" indicating when the ink was manufactured and / or first introduced into the bottle 52, recommended printhead 30 operating parameters for the particular ink in the bottle 52, and the like. Data may be read from and / or written to the RFID element using an appropriate read / write device in the card processing system 10 or the card printing system 12.

[0045] In one embodiment, the RFID element on the ink supply bottle 52 can be used to control the return pump 58. For example, the RFID element can be used to control the speed of the return pump 58 based on the estimated amount of remaining ink in the ink supply bottle 52. When the amount of remaining ink is small, the speed of the return pump 58 can be reduced because it does not take a lot of force to return the recirculated ink to the ink supply bottle 52 to achieve adequate mixing. Conversely, when the amount of remaining ink is large, the speed of the return pump 58 can be increased because it takes a lot of force to return the recirculated ink to the ink supply bottle 52 to achieve adequate mixing.

[0046] Figure 4 Another embodiment of a DOD card printing system 12 is shown. The DOD card printing system 12 is similar to Figure 2 and Figure 3 The DOD card printing system 12 in FIG. 1 is shown in FIG. 1 and like elements are referred to using like reference numerals, some of which have a "-2" added thereto. Figure 4 The system 12 in utilises what may be referred to as an active mixing ink supply bottle design, in which a controllable valve is used to dictate whether mixing occurs within the ink supply bottle 52 or via local recirculation / mixing.

[0047] For more information, see Figure 4The ink delivery system 32-2 includes a pair of controllable valves 110a, 110b (e.g., a three-way solenoid valve), a single pump 112, and a check valve 114 located between the ink collecting tanks 44, 54 and the ink supply bottle 52. The valves 110a, 110b are configured to have at least three states, which provide at least three flow paths for the ink. The first state of the valves 110a, 110b is the state when the ink collecting tank 44 needs ink. At this time, the valves 110a, 110b are both set to allow ink to be pumped from the ink supply bottle 52 to the ink collecting tank 44 by the pump 112. The second state of the valves 110a, 110b is the state when the ink collecting tank 54 is full of ink. At this time, the valves 110a, 110b must be set to allow ink to be pumped from the ink collecting tank 54 to the ink supply bottle 52 by the pump 112. The third state of the valves 110a, 110b is the state when the ink supply bottle 54 is removed, at which time the valves 110a, 110b must be set to allow ink to be pumped from the ink collection tank 54 to the ink collection tank 44 by the pump 112 for local recirculation. The check valve 114 is provided to prevent excessive pressure accumulation when the valves 110a, 110b are set to pump to the ink supply bottle 52 but the ink supply bottle 52 is not actually present.

[0048] Figure 4 The system 12 in the embodiment also includes an isolation valve 76 in the vacuum system (in Figure 2 2 (a similar isolation valve is shown in ). The isolation valve 76, which may be, for example, a solenoid valve, provides the ability to isolate the ink system 32-2 from the vacuum system 34-2 and helps maintain the vacuum in the event of a power outage. However, in a recirculating ink system (such as system 32-2), since adding and removing ink may result in significant pressure changes, it is desirable to always have adequate damping (regardless of the state of the isolation valve 76). This may cause problems when the isolation valve 76 is closed and ink continues to recirculate. Without damping (due to the isolation valve 76 being closed, resulting in the damping reservoir 70 being isolated from the ink system 32-2), the pump 112 may result in large and steep pressure spikes, which may disturb the meniscus in the nozzle and result in poor print quality.

[0049] Therefore, if Figure 4 As shown, a second damping chamber 80 (or a second pressure damping container) is provided in the ink delivery system 32-2 downstream of the isolation valve 76. For example, the second damping chamber 80 can be fluidically connected to the ink collecting tank 44, such as connected to the fluid pipeline between the ink collecting tank 44 and the isolation valve 76. In addition, the second damping chamber 80 is fluidically connected to the ink collecting tank 54 through the vacuum line 74 having a valve 82. The second damping chamber 80 is sealed without a slow leak device so that the second damping chamber 80 retains the ability to maintain a vacuum when the power is off. Figure 2 and Figure 3 The illustrated embodiment may utilize an isolation valve 76 and a second damping chamber 80 .

[0050] Figure 4 The system 12 includes reference Figure 2 Valve 51, system drain line 100 and system drain pump 102 are illustrated.

[0051] The examples disclosed in this application should be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than by the foregoing description; and all changes made within the meaning and scope of the equivalent content of the claims should be included in the present invention.

Claims

1. A method of operating a drop-on-demand card printing system of a card processing system, the drop-on-demand card printing system comprising an ink supply system connected to a drop-on-demand ink print head, the ink supply system having a first ink reservoir fluidly connected to an ink inlet, a second ink reservoir fluidly connected to an ink outlet, and a disposable ink supply bottle, the method comprising: When the first set of ink tanks needs ink supply, the ink is pumped directly from the disposable ink supply bottle into the first set of ink tanks; and When it is necessary to remove ink from the second ink set tank, the ink is pumped directly from the second ink set tank into the disposable ink supply bottle, thereby causing mixing of the ink within the disposable ink supply bottle.

2. The method of claim 1, wherein pumping ink from the ink supply bottle directly into the first ink collecting tank is performed using a first pump, and pumping ink from the second ink collecting tank directly into the ink supply bottle is performed using a second pump.

3. The method of claim 1, wherein pumping ink from the ink supply bottle directly into the first ink collecting tank and pumping ink from the second ink collecting tank directly into the ink supply bottle are performed using a single pump.

4. An on-demand inkjet card printing system for a card processing system implementing the method of claim 1.

5. An on-demand inkjet card printing system for a card processing system, the on-demand inkjet card printing system comprising: an ink delivery system connected to the drop-on-demand inkjet printhead, the ink delivery system comprising a first ink collection tank fluidly connected to the ink inlet, a second ink collection tank fluidly connected to the ink outlet, and a disposable ink supply bottle; The ink delivery system is configured to pump ink directly from the disposable ink supply bottle into the first ink collection tank when the first ink collection tank needs ink supply; and to pump ink directly from the second ink collection tank into the disposable ink supply bottle when ink needs to be removed from the second ink collection tank, thereby causing mixing of the ink in the disposable ink supply bottle.

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