Ink delivery system

Abstract

An ink delivery system for providing ink to a printhead. The ink delivery system includes a sump, a head tank, an ink flow passage between the sump and the head tank, and a pump for pumping ink from the sump through the ink flow passage into the head tank. The ink delivery system also includes a housing and a heater. The housing contains the sump, the head tank, and the ink flow passage. The housing includes an outer wall for transferring heat from the heater to the ink in the ink flow passage.

Description

[Technical Field]

[0001] This invention relates to an ink delivery system suitable for use in printing systems, and a method for manufacturing the ink delivery system. [Background Technology]

[0002] In printing systems such as inkjet printers, the printhead is used to deposit ink onto a substrate. The purpose of the ink delivery system is to supply ink to one or more printheads. To obtain optimal print quality, it is preferable to supply ink at a specific target ink temperature and pressure. If the ink temperature supplied to the printhead deviates significantly from the target ink temperature, print quality problems will occur.

[0003] In a recycled ink system, such as that disclosed in U.S. Patent No. 8,444,259B2, ink from the recycled ink system flows into and out of the printhead, recirculates around the ink system, and flows back to the printhead. In such a system, the amount of ink circulating in the system decreases as ink is deposited onto the substrate. When the amount of ink in the recycled ink delivery system falls below a certain threshold, new ink can be supplied from the bulk ink delivery system to the recycled system.

[0004] In existing printing systems, ink is supplied from the bulk ink delivery system to the ink delivery system via an in-line heater, ensuring that the new ink enters the system at a temperature close to the target ink temperature. This requires rapidly heating the new ink from ambient room temperature to the target ink temperature, which may necessitate high-power heaters.

[0005] [List of Citations]

[0006] [Patent Documents]

[0007]

PTL 1

[0008] [Technical Issues]

[0009] This invention aims to provide a method for effectively maintaining the temperature of ink circulating in an ink delivery system. The system is designed to efficiently utilize a single heater to heat newly supplied ink to the ink delivery system and maintain the temperature of ink circulating within it. Therefore, the ink delivery system can efficiently utilize fewer components. This promotes system sustainability by reducing material and energy consumption and costs associated with the system's manufacture, operation, and maintenance. Furthermore, the ink delivery system of this invention is designed to be compact while allowing easy access to components most likely to require maintenance. This invention also aims to provide an economical method for manufacturing an ink delivery system without increasing construction time.

[0010] [Problem Solving]

[0011] According to the present invention, an ink delivery system for supplying ink to a printhead includes a sump tank for containing ink and having an ink inlet for receiving ink from a bulk ink delivery system, a sump tank inlet for receiving ink from the printhead, and a sump tank outlet for supplying ink to a header tank. The header tank contains ink and has a header inlet for receiving ink from the sump tank and a header outlet for supplying ink to the printhead. The ink delivery system further includes an ink flow channel between the ink tank and the water tank. The ink delivery system also includes a pump for pumping ink from the sump tank into the header tank through the ink flow channel. The ink delivery system further includes a housing housing the sump tank, the header tank, and the ink flow channel. The housing includes an outer wall for transferring heat to the ink in the ink flow channel. The ink delivery system further includes a heater for heating the outer wall of the housing.

[0012] Optionally, the outer wall includes an inner surface that defines the ink flow channel. Optionally, the outer wall includes an outer surface on the exterior of the housing. The heater can be used to heat the outer surface of the outer wall.

[0013] Optionally, the ink flow channel is configured to allow the ink in the ink flow channel to contact the inner surface of the outer wall of the housing.

[0014] Optionally, the ink flow channel is used to guide ink along an ink flow path between the oil pan outlet and the head inlet; wherein the ink flow path follows an indirect route from the oil pan outlet to the head inlet. Optionally, the ink flow path is spiral or tortuous.

[0015] Optionally, the ink delivery system further includes an inner housing disposed within the outer housing and including an outer surface on the exterior of the inner housing; and one or more ridges between the inner housing and the outer housing. The ink flow channel may be defined by the inner surface of the outer housing, the outer surface of the inner housing, and the one or more ridges.

[0016] Optionally, the oil pan tank and the head tank are housed within the inner shell.

[0017] Optionally, the inner shell forms the oil pan tank and the head tank.

[0018] Optionally, the shape of the one or more ridges defines the route of the ink flow path from the oil pan outlet to the head inlet between the inner shell and the outer shell.

[0019] Optionally, the heater is used to heat the ink in the ink flow channel so that the ink enters the head storage tank at a target ink temperature between 45°C and 55°C.

[0020] Optionally, the heater is configured to contact the housing in the longitudinal direction of the housing, in the region extending between the oil pan outlet and the head inlet.

[0021] Optionally, the heater is an electric heater.

[0022] Optionally, the oil pan tank is disposed at the other end of the outer shell, opposite to the head tank, in the longitudinal direction of the outer shell.

[0023] Optionally, the outer casing is cylindrical, and the ink delivery system is configured to keep the head tank above the oil pan during use.

[0024] Optionally, the ink delivery system further includes a return tank for containing ink, having a return inlet for receiving ink from the printhead, a return overflow inlet for receiving ink from the printhead reservoir, and a return overflow outlet for allowing ink exceeding a predetermined threshold level in the return tank to flow to the oil pan reservoir. The printhead reservoir may include a printhead overflow outlet for allowing ink exceeding a predetermined threshold level in the printhead reservoir to flow to the return tank. The ink delivery system may be configured such that the return tank is below the printhead reservoir and above the oil pan during use.

[0025] Optionally, the ink delivery system includes an opening providing a vent from the head tank to the atmosphere.

[0026] Optionally, the ink delivery system further includes an ink filter disposed within the housing and used to filter ink flowing through the ink flow channel.

[0027] Optionally, the ink delivery system further includes a control system for setting a target temperature for the heater based on ink information supplied from the bulk ink delivery system to the oil pan.

[0028] According to the present invention, a printing system includes: the ink delivery system, a bulk ink delivery system for supplying ink to the oil pan reservoir via the ink inlet; and a printhead. The ink delivery system is used to supply ink to the printhead.

[0029] According to the present invention, a method for manufacturing an ink delivery system includes an additive manufacturing step. [Attached Image Description]

[0030] The invention will now be described in conjunction with exemplary embodiments and the accompanying drawings, wherein:

[0031] [ Figure 1 ]

[0032] Figure 1 This is a schematic diagram of a printing system, including the ink delivery system.

[0033] [ Figure 2A ]

[0034] Figure 2A This is a schematic diagram of an ink delivery system according to an embodiment of the present invention, showing the housing viewed from the front.

[0035] [ Figure 2B ]

[0036] Figure 2B yes Figure 2A A cross-sectional view of the drum (AA section).

[0037] [ Figure 3A ]

[0038] Figure 3A yes Figure 2A The schematic diagram of the ink delivery system also includes heaters arranged around the housing when viewed from the side.

[0039] [ Figure 3B ]

[0040] Figure 3B yes Figure 3A BB cross-sectional view of the drum body.

[0041] [ Figure 4 ]

[0042] Figure 4 yes Figure 2A A schematic diagram of the internal structure of the ink delivery system, showing the inner shell and ridge.

[0043] [ Figure 5A ]

[0044] Figure 5A This is an internal schematic diagram of an ink delivery system according to an embodiment of the present invention, showing the inner shell and the ridge.

[0045] [ Figure 5B ]

[0046] Figure 5B This is an internal schematic diagram of an ink delivery system according to an embodiment of the present invention, showing the inner shell and the ridge.

[0047] [ Figure 6 ]

[0048] Figure 6 This is a schematic diagram of the first end cap of an ink delivery system according to an embodiment of the present invention.

[0049] [ Figure 7 ]

[0050] Figure 7 This is a schematic diagram of the second end cap of an ink delivery system according to an embodiment of the present invention.

[0051] [ Figure 8 ]

[0052] Figure 8 This is a schematic diagram of a printing system that includes an ink delivery system with a return tank.

[0053] [ Figure 9A ]

[0054] Figure 9A This is a schematic diagram of an ink delivery system, each of which includes a head tank with multiple chambers and a return tank with multiple chambers.

[0055] [ Figure 9B ]

[0056] Figure 9B This is a schematic diagram of an ink delivery system, each of which includes a head tank with multiple chambers and a return tank with multiple chambers.

[0057] [ Figure 10 ]

[0058] Figure 10 This is a schematic diagram of a printing system according to an embodiment of the present invention, including a printhead, a recording medium, and an ink delivery system.

Detailed Implementation Methods

[0059] Printing System Overview

[0060] A printing system is used to form a printed image on a substrate, such as paper. One printing system includes an ink delivery system for supplying ink to one or more printheads, which deposit portions of the ink onto the substrate to form the printed image. The ink delivery system is preferably a self-contained unit that can be detachably attached to the printing system. The ink delivery system can be removed from the printing system, for example, for maintenance or replacement of different ink delivery systems.

[0061] Example of printing system 200 Figure 1As shown. The printing system 200 includes an ink delivery system 100, a printhead 210, and a bulk ink delivery system 220. The ink delivery system is used to deliver ink along... Figure 1 The ink flows in the direction indicated by the middle arrow. The ink delivery system is used to receive new ink from the bulk ink delivery system 220 and supply ink to the printhead 210. The printhead 210 is used to deposit ink, for example, to print an image onto a substrate. The ink delivery system is configured such that ink supplied to the printhead 210 but not deposited for printing continues to flow through the ink delivery system.

[0062] although Figure 1 Only one printhead 210 is shown, but the printing system may include multiple printheads. Preferably, the printing system includes at least four printheads. The printing system may include multiple ink delivery systems. Each ink delivery system of the printing system can be used to supply ink to a single corresponding printhead. In this way, each printhead can be dedicated to printing a specific color of ink and can supply that color of ink to the corresponding ink delivery system. The printing system may have multiple printheads for each color, for example, when high-speed printing is enabled, in which case each ink delivery system can provide multiple printheads. The printing system may be able to print more than four colors, such as five or six. In this case, in addition to CMYK, the printing system can also print special colors, such as white or metallic colors.

[0063] like Figure 1 As shown, the ink delivery system 100 includes an ink sump tank 110 and a head tank 120. Both the ink sump tank 110 and the head tank 120 are used to contain ink. The ink sump tank 110 has an ink inlet 111 for receiving ink from the bulk ink delivery system 220. The ink sump tank 110 also has an ink sump inlet 113 for receiving ink from the printhead 210. The ink sump tank 110 also has an ink sump outlet 112 for supplying ink to the head tank 120. The head tank 120 has a head inlet 121 for receiving ink from the ink sump tank 110 and a head outlet 122 for supplying ink to the printhead 210.

[0064] Figure 1 The ink delivery system 100 also includes an ink flow channel 12 between the sump tank 110 and the head tank 120. The ink flow channel 12 facilitates fluid communication between the sump tank 110 and the head tank 120. Specifically, the ink flow channel 12 is preferably used to receive and guide ink pumped from the sump outlet 112 to the head inlet 121. The ink delivery system includes a pump 140 for pumping ink from the sump tank 110 into the head tank 120 through the ink flow channel 12.

[0065] The ink is preferably supplied to the printhead 210 at a target ink temperature. The target ink temperature can be between 40°C and 60°C, more preferably between 45°C and 55°C, and even more preferably between 48°C and 52°C. An acceptable deviation from the target temperature can be ±5°C, preferably ±2°C, more preferably ±1.5°C, and even more preferably ±1°C. If the ink is supplied at a temperature exceeding the acceptable margin of deviation from the target ink temperature, print quality will be reduced. Preferably, the ink in the printhead reservoir 120 is maintained at the target ink temperature. In this way, the ink supplied from the printhead reservoir 120 to the printhead 210 does not require significant heating or cooling to achieve an acceptable temperature by passing through the printhead. The ink delivery system is preferably used to maintain the ink in the printhead reservoir at the target ink temperature, especially during printing. The printhead 210 may be equipped with a heater to maintain the ink at the target ink temperature.

[0066] The arrangement of the heater and ink flow channel enables efficient heat transfer of the ink within the ink delivery system. New ink supplied from the bulk ink delivery system and ink already circulating within it are both provided to the sump and pumped to the head tank via the ink flow channel. Therefore, as the ink flows through the ink flow channel, the heater simultaneously heats both the new, cooler ink and the previously circulated ink. This arrangement allows the ink to be easily maintained at a temperature within acceptable deviations from the target temperature.

[0067] Bulk ink delivery system 220 is used to supply ink to oil pan tank 110 via ink inlet 111. The bulk ink delivery system can contain ink at room temperature. The temperature at which ink from bulk ink delivery system 220 is supplied to oil pan tank 110 can be ambient room temperature. For example, the ink supplied from bulk ink delivery system 220 to oil pan tank 110 can be below 30°C, possibly below 20°C.

[0068] The ink delivery system 100 is used to heat the ink in the ink delivery system 100 so that the ink in the printhead reservoir 120 is at a target ink temperature. Overheating of the ink can cause ink damage, and even if the ink is cooled to the target ink temperature before being deposited from the printhead 210, this can still result in poor print quality. Therefore, preferably, the ink delivery system 100 is configured such that the ink in the ink delivery system does not exceed a predetermined maximum ink temperature. The predetermined maximum ink temperature is, for example, 60°C, preferably 55°C.

[0069] Ink delivery system

[0070] Ink delivery system such as Figure 2A , 2B As shown in Figures 2 and 3A, and 3B. The ink delivery systems of Figures 2 and 3 are suitable for providing... Figure 1The ink delivery system 100 in the printing system 200. A front view of the ink delivery system is shown below. Figure 2A As shown, and Figure 2B Provided passage Figure 2A A cross-sectional view of the ink delivery system, AA. A side view of the ink delivery system having heaters 180 disposed around the exterior of the housing, as shown. Figure 3A As shown, and Figure 3B Provided passage Figure 3A A cross-sectional view of the ink delivery system BB. An enlarged view of the ink flow channel 12 is also provided. Figure 3B middle.

[0071] like Figure 2A , 2B The ink delivery systems shown in 3A and 3B include a housing 150 that houses an oil pan tank 110, a head tank 120, and an ink flow channel 12. The housing includes an outer wall 153. The outer wall 153 is used to transfer heat to the ink in the ink flow channel 12.

[0072] With this arrangement, the heater is ideally used to heat the new ink supplied to the ink delivery system and maintain the temperature of the ink as it circulates through the system. Thus, a separate heater specifically for heating the new ink supplied from the bulk ink delivery system is unnecessary. Avoiding the need for a separate heater allows for a reduction in the size and complexity of the ink delivery system by decreasing the number of components, resulting in a more compact system. Furthermore, the reduction in the number of components lowers the costs and energy associated with system manufacturing.

[0073] shell

[0074] The ink delivery system includes a heater for heating the outer wall of the housing. Figure 2B and Figure 3B In the illustrated arrangement, the outer wall 153 includes an inner surface that defines the surface of the ink flow channel 12. The outer wall 153 also includes an outer surface on the exterior of the housing 150. Preferably, the ink flow channel 12 is configured to contact the ink in the ink flow channel 12 with the inner surface of the outer wall 153 of the housing 150.

[0075] In this configuration, a heater is used to heat the outer surface of the outer wall. The outer wall 153 is used to transfer heat from the heater 180 to the ink in the ink flow channel 12. The outer wall 153 is preferably used for heat conduction. The outer wall may comprise aluminum. Specifically, the outer wall may be an aluminum wall. Figure 3A and 3B As shown, heater 180 can contact the outer wall 153.

[0076] Alternatively, the outer wall may not include the inner surface that defines the ink flow path. Instead, the ink flow path may be defined by an inner wall disposed within the housing. The ink delivery system may be configured to transfer heat from the outer wall to the inner wall. For example, the outer wall may be configured to contact the inner wall, or a conductive layer may be disposed between the outer and inner walls to transfer heat from the outer wall to the inner wall.

[0077] Ink flow channel

[0078] According to Figures 2 and 3, the internal structure of the ink delivery system is as follows: Figure 4 As shown. The outer wall 153 of the housing 150 in Figures 2 and 3 is not shown, so that the interior of the ink delivery system below the outer wall 153 is visible.

[0079] like Figure 4 The ink delivery system shown includes an inner housing 160. The inner housing 160 is disposed within the outer housing ( Figure 4 (Not shown) Inside. The inner shell includes the outer surface of the inner shell. For example... Figure 4 As shown, a ridge 170 is provided on the outer surface of the inner shell. Preferably, the ink delivery system is configured such that the ridge 170 is positioned between the inner shell 160 and the outer shell 150 when the outer shell is in place. Alternatively, more than one ridge may be provided on the outer surface of the inner shell.

[0080] The ink flow channel can be defined by the inner surface of the housing 150, the outer surface of the inner housing, and one or more ridges. Specifically, as... Figure 3B As shown, the ink flow channel 12 can be defined by the inner surface of the outer wall 153 of the outer shell 150, the outer surface of the inner shell 160, and one or more ridges 170.

[0081] An ink flow channel guides ink along an ink flow path between the oil pan outlet and the head inlet. The ink flow path preferably follows an indirect route from the oil pan outlet to the head inlet; for example, the path may follow a meandering or spiral route. In a meandering route, the ink flow path follows a winding route, preferably, the ink flow path is redirected in a first direction around the inner circumference of the housing, redirected to the longitudinal direction of the housing, and then redirected to a second direction. Preferably, the first direction is a first circumferential direction of the housing, and the second direction is a relative circumferential direction of the housing. With a spiral route, the spiral defined by the ink flow path can have a constant diameter. Alternatively, the diameter of the spiral can vary along the longitudinal direction of the housing. For example, the diameter at the oil pan outlet can be larger than the diameter at the head inlet, or the diameter at the oil pan outlet can be smaller than the diameter at the head inlet. The ink flow channel does not need to be a precise spiral; for example, the pitch of the spiral can vary. The ink flow channel can be a combination of spiral and meandering paths.

[0082] The shape of one or more ridges preferably defines the route of the ink flow path from the oil pan outlet to the head inlet between the inner and outer shells. Figure 5A A cross-section of the inner shell 160 with a ridge 170 is shown, which is consistent with... Figure 4 Similarly, the spiral flow path is defined as 175. In Figure 4 and Figure 5A In the middle, the inner shell 160 is usually cylindrical, to correspond to the outer shell which is usually cylindrical. Figure 5B An alternative arrangement is shown, which has an inner shell 160 that is typically cubic, corresponding to an outer shell that is typically cubic. Figure 5B A cross-section of the inner shell 160 with a ridge 170 defining a tortuous flow path 175 is shown. Figure 5B As shown, the flow path extends in a tortuous manner along one die of the cubic inner shell. Alternatively, the ridges can be configured such that the flow path narrows around multiple sides of the inner shell. Similarly, the tortuous flow path is not limited to a cubic inner shell. For example, a tortuous flow path can be provided around a cylindrical inner shell.

[0083] like Figure 2B and 3B As shown, the oil pan tank 110 is preferably disposed at the other end of the outer casing 150 opposite the head tank 120 in the longitudinal direction X. Preferably, the heater 180 is configured to contact the outer casing 150 in the region extending between the oil pan outlet and the head inlet in the longitudinal direction of the outer casing 150, such as... Figure 3B As shown.

[0084] Preferably, the ink flow path does not directly enter the head inlet from the oil pan outlet simply because the direct path is shorter than the indirect path. With a longer indirect path, the ink can further traverse the ink flow channel. Therefore, the ink may remain in the ink flow channel for a longer time than it would in the case of a shorter ink path. As described above, the ink delivery system is preferably configured to heat the ink in the ink flow channel so that the ink enters the head tank at a target ink temperature. If the ink passes through the ink flow channel too quickly, less time is available for heat distribution to the ink in the ink flow channel before it reaches the head tank. Therefore, a longer path between the oil pan outlet and the head inlet allows for more efficient heating of the ink in the ink flow channel.

[0085] This method of heating the ink avoids the need for a separate online heater to directly heat the ink supplied by the bulk ink delivery system. It reduces the number of components, lowers initial costs, and decreases maintenance time and costs.

[0086] heater

[0087] The heater is preferably used to heat the ink in the ink flow channel so that the ink enters the head storage tank at a target ink temperature. The target ink temperature is preferably between 40 and 60°C, more preferably between 45 and 55°C, and even more preferably between 48 and 52°C.

[0088] The heater can be any heater suitable for heating the ink to the target ink temperature. The heater is preferably controllable and preferably capable of rapid temperature change. This allows the heater temperature to be adjusted to accommodate a sudden supply of new ink, such as when printing images requiring a large amount of ink. The heater is preferably an electric heater. The heater power can be between 400W and 1400W. Preferably, the heater power is between 600W and 1200W, more preferably between 800W and 1000W. The heater power can depend on the size of the ink delivery system. In particular, the heater power can depend on the ink capacity contained in the configured ink delivery system. For example, a larger ink capacity in the ink delivery system allows for a higher heater power. Preferably, the ink delivery system is configured to contain 5 to 15 liters of ink, more preferably 8 to 12 liters of ink, and even more preferably 10 liters of ink.

[0089] The heater preferably includes a heating portion configured to conform to the shape of the housing. The heater may include a heating pad. Heat that can contact the housing is used to heat the ink in the ink flow channels.

[0090] The heater can preferably be in large contact with the housing and positioned along the length of the ink flow path. This minimizes ink temperature fluctuations in the ink delivery system, making it easier to maintain the ink within acceptable deviations from the target temperature.

[0091] Compact ink delivery system

[0092] The sump tank 110 and the head tank 120 can be housed within the inner shell 160. Alternatively, as... Figure 2B and Figure 3B As shown, the inner shell can form both an oil sump tank and a head tank. In other words, the walls of the inner shell can define the oil sump tank and / or the head tank. These walls of the inner shell can also define ink flow channels. Similarly, one or more ridges can be provided on the exterior of the oil sump tank and / or the head tank.

[0093] like Figure 2A Figure 3 Figure 4 , Figure 6 and Figure 7 As shown, the ink delivery system may include end caps. In particular, the housing 150 may include at least one end cap. Preferably, in the longitudinal direction of the housing 150, the housing includes a first end cap 151 at one end of the housing 150 and a second end cap 152 at the other end of the housing 150.

[0094] The first end cap 151 is preferably located at the longitudinal end of the outer casing closest to the oil pan tank. The pump 140 can be attached to the outer casing 150 via the first end cap 151.

[0095] The ink delivery system may include one or more sensors. The one or more sensors may include an ink temperature sensor for measuring the temperature of the ink in the ink delivery system. The one or more sensors may include an ink pressure sensor for measuring the pressure of the ink flow through the ink delivery system. The one or more sensors may include an ink level sensor for measuring the ink level in one or more ink tanks of the ink delivery system, such as an oil pan tank or a head tank. The ink level sensor may be, for example, a float switch, a light level switch, an ultrasonic sensor, or any other suitable sensor for measuring the ink level in the ink tank. The ink level is determined based on data from the pressure sensor. The pressure sensor may be located on a first end cap and used to measure the pressure in the oil pan tank.

[0096] The sensor may include sensor electronics 101, such as a sensor chip, such as Figure 7 As shown. The sensor electronics 101 is preferably housed within the housing. More preferably, the sensor electronics 101 is disposed in one of the end caps, such as the first end cap 151. With this arrangement, the electronics are preferably disposed at one end of the housing without increasing the overall footprint of the ink delivery system. Therefore, the ink delivery system can be compact.

[0097] An ink delivery system may include an ink filter housing for housing an ink filter. The ink filter housing is preferably disposed within a housing. As shown in the figure, for example, in... Figure 2B and Figure 6 The ink delivery system may include an ink filter 190 to filter ink circulating in the ink delivery system. Preferably, the ink filter 190 is disposed within a housing 150. More preferably, the ink filter 190 is used to filter ink flowing through the ink flow channel 12. The ink filter and / or ink filter housing are disposed within the housing, which is intended to allow the ink delivery system to be compact with most of the components contained within the housing. This compact design allows the ink delivery system to be easily deployed to different printing systems, even in limited spaces and areas with restricted access for installation and maintenance.

[0098] In particular, such as Figure 2B and Figure 6 As shown, the ink filter housing can be accessed via an end cap (e.g., a second end cap 152). For example, as Figure 6As shown, the second end cap 152 may include a filter port 191 for allowing access to the ink filter housing. The filter port 191 is preferably configured to allow the removal and replacement of the ink filter. The filter port 191 may include a filter port cover for opening to provide access to the ink filter. When closed, the filter port cover prevents external debris from entering the housing via the filter port 191. Therefore, the ink filter can be easily replaced for maintenance.

[0099] With this configuration, components such as ink filters and sensors can be included within the housing, making the ink delivery system compact and available as a discrete unit for installation in a corresponding printing system.

[0100] Consistent ink flow from the printhead

[0101] Preferably, the ink delivery system is configured such that the head tank 120 is higher than the oil pan tank 110 during use. Preferably, the head tank 120 is positioned directly above the oil pan tank 110 during use. Alternatively, the outer casing may be angled to the vertical direction during use, such that the head tank is not directly above the oil pan tank, but is positioned higher than the oil pan tank.

[0102] In addition, the ink delivery system may include an opening 125 that provides ventilation from the head tank 120 to the atmosphere. For example, as Figure 2B and Figure 6 As shown, the opening 125 can be provided in the second end cover 152 of the housing 150, and the head tank 120 is provided at the end of the housing 150 closest to the second end cover 152, which is the upper end of the housing 150 during use.

[0103] This arrangement allows gas to be vented from the system, reducing air bubbles in the ink. Furthermore, gravity helps the ink travel from the head reservoir 120 to the printhead 210 and from the printhead 210 to the oil pan reservoir 110. This helps reduce pressure fluctuations and improve print quality.

[0104] The ink delivery system preferably includes a return tank 130, such as Figure 2B , Figure 3B and Figure 8 As shown. The return tank 130 is used to contain ink and has a printing ink inlet 133 for receiving ink from the printhead 210, and a return overflow inlet 132 for receiving ink from the printhead reservoir 120. The return tank 130 also has a return overflow outlet 131 for allowing ink exceeding a predetermined threshold level in the return tank 130 to flow into the oil pan reservoir 110. Specifically, as... Figure 8As shown, ink can flow from the return overflow outlet 131 of the return tank 130, and through the return overflow channel 31 to the oil sump inlet 113 of the oil sump tank 110. In this configuration, as... Figure 8 As shown, the head reservoir 120 includes a head overflow outlet 123, which is configured to allow ink exceeding a predetermined threshold level in the head reservoir 120 to flow into the return reservoir 130. Specifically, ink flows from the head overflow outlet 123 through the head overflow channel 23 to the return overflow inlet 132. The ink delivery system is configured such that the return reservoir 130 is below the head reservoir and above the oil pan during use. With the aid of gravity, this arrangement promotes a constant flow of ink from the head reservoir, through the printhead, and into the return reservoir.

[0105] Pump 140 is configured to supply ink from the sump tank 110 to the head tank 120. However, by means of... Figure 8 In the arrangement shown, ink can flow from the head reservoir 120 to the printhead 210 without active pumping from the head reservoir 120. Therefore, the ink flows to the printhead 210 due to gravity. Consequently, the ink flow pressure at the printhead is more constant than in a configuration where a pump is needed to actively force the ink to the printhead. Figure 8 As shown, printhead 210 may include a printface level 216. The printface is the lower surface of the printhead from which ink is deposited during use.

[0106] Preferably, the printing system 200 is configured such that the print head 210 is positioned vertically between the return tank 130 and the head reservoir 120, as shown below. Figure 8 As shown. The vertical distance between the return tank 130 and the printhead 210 is preferably 50% to 70% of the vertical distance between the return tank 130 and the head reservoir 120, more preferably 55% to 65%, and even more preferably 60%. In particular, the vertical distance L1 between the ink level 136 in the return tank 130 and the printing surface level 216 of the printhead 210 is preferably 50% to 70% of the vertical distance L2 between the ink level 136 in the return tank 130 and the ink level 126 in the head reservoir 120, more preferably 55% to 65%, and even more preferably 60%. This arrangement helps to maintain ideal pressure in the printhead.

[0107] Optionally, or additionally, the pressure at the printhead can also be controlled by altering the pressure drop upstream or downstream of the printhead. For example, this can be achieved by limiting the ink flow upstream of the printhead to reduce the pressure at the printhead and / or by limiting the ink flow downstream of the printhead to increase the pressure at the printhead.

[0108] The ink delivery system can be configured to actively change the vertical distance between the return tank 130 and the head reservoir 120. For example, the return tank 130 can be actuated to move longitudinally along the housing. Additionally, or optionally, the ink delivery system can be actuated to tilt to change the vertical distance between the head reservoir and the return tank. Additionally, or optionally, the printing system can also be configured such that the vertical position of the printhead can change relative to the ink delivery system. In particular, the ink delivery system can be actuated to change its vertical position relative to the printhead.

[0109] As above, combined with Figure 8 The head overflow outlet 123 can be used to ensure that the ink in the head tank 120 does not exceed a predetermined threshold level. Similarly, the return overflow outlet 131 can be configured to ensure that the ink in the return tank 130 does not exceed a predetermined threshold level. For example, the outlet can be located at a predetermined distance from the bottom of the corresponding tank. In this way, the distance between the tank bottom and the outlet can correspond to the depth of ink at the predetermined threshold level in that tank. If the ink level in the tank reaches the predetermined threshold level, it will overflow to the tank below. Therefore, this is a method of maintaining the ink at the desired level in the tank.

[0110] Optionally or additionally, the ink level can be maintained by providing multiple chambers to the head reservoir 120 and / or return reservoir 130, for example, as Figure 9A and 9B As shown.

[0111] like Figure 9A As shown, the head storage tank 120 may include a first chamber 120a and a second chamber 120b. Figure 9A In this arrangement, the head inlet 121 can be configured to allow ink to enter the first chamber 120a. Therefore, during use, ink from the oil pan reservoir 110 can be pumped to the first chamber 120a of the head reservoir 120. The head outlet 122 can be configured to supply ink from the first chamber 120a to the printhead. The first chamber 120a of the head reservoir 120 is preferably configured such that the ink level 126 in the first chamber 120a does not exceed the ink level 126. The first chamber 120a of the head reservoir 120 can be configured such that ink overflows into the second chamber 120b of the head reservoir 120, ensuring that the ink level 126 in the first chamber 120a does not exceed the ink level 126. Figure 9A In the arrangement, the second chamber 120b of the head storage tank 120 is configured to discharge to the return tank 130 via the head overflow channel 23.

[0112] like Figure 9A As shown, the reflux tank 130 may include a first chamber 130a and a second chamber 130b. Figure 9AIn this arrangement, the return inlet 132 can be configured to allow ink to enter the first chamber 130a. During use, ink overflowing from the printhead reservoir 120 can therefore be discharged into the first chamber 130a of the return tank 130. The printing ink inlet 133 can be configured to supply ink from the printhead to the first chamber 130a of the return tank 130. The first chamber 130a of the return tank 130 is preferably configured such that the ink level does not exceed 136 in the first chamber 130a. The first chamber 130a of the return tank 130 can be configured such that ink overflows into the second chamber 130b of the return tank 130, such that the ink level in the first chamber 130a does not exceed 136. Figure 9A In the arrangement, the second chamber 130b of the return tank 130 is used to discharge to the oil pan storage tank 110 via the return overflow channel 31.

[0113] like Figure 9B As shown, the head storage tank 120 may include a first chamber 120a, a second chamber 120b, and a third chamber 120c. Optionally or additionally, the return tank 130 may also include a first chamber 130a, a second chamber 130b, and a third chamber 130c. Figure 9B In this arrangement, the head inlet 121 can be configured to allow ink to enter the first chamber 120a. Therefore, during use, ink from the oil pan reservoir 110 can be pumped to the first chamber 120a of the head reservoir 120. The first chamber 120a is configured such that ink overflows to the second chamber 120b at a certain level. The head outlet 122 can be configured to supply ink from the second chamber 120b to the printhead. The second chamber 120b of the head reservoir 120 can be configured such that ink overflows to the third chamber 120c of the head reservoir 120, such that the ink in the second chamber 120b does not exceed the ink level 126. Figure 9B In the arrangement, the third chamber 120c of the head storage tank 120 is used to discharge the return tank 130 via the head overflow channel 23.

[0114] exist Figure 9B In this arrangement, the return inlet 132 can be configured to allow ink to enter the first chamber 130a. During use, ink overflowing from the printhead reservoir 120 can therefore be discharged into the first chamber 130a of the return tank 130. The first chamber 130a is configured such that ink overflows to a second chamber 130b at a certain level. The printing ink inlet 133 can be configured to supply ink from the printhead to the second chamber 130b of the return tank 130. The second chamber 130b of the return tank 130 can be configured such that ink overflows into a third chamber 130c of the return tank 130, such that the ink in the second chamber 130b does not exceed the ink level 136. Figure 9B In the arrangement, the third chamber 130c of the return tank 130 is used to discharge into the oil pan storage tank 110 via the return overflow channel 31.

[0115] The printhead reservoir has multiple chambers. A predetermined threshold level, or ink level 126, is ideally set based on the ink level in the chamber where the printhead outlet 122 is located. Similarly, in the return reservoir, the ink level 136 is ideally set based on the ink level in the chamber where the printing ink inlet 133 is located. Thus, the ink level in the chamber that most directly supplies ink to or receives ink from the printhead is used to control the printhead pressure.

[0116] This arrangement can be expected to reduce the risk of pump pressure fluctuations, which can adversely affect the pressure on the printing surface. It can also be expected to reduce the risk of air bubbles being transferred from the pump to the printhead. Specifically, any air bubbles in the ink pumped into the printhead reservoir will tend to remain on the surface of the first chamber of the printhead reservoir. Even if these air bubbles (along with the ink overflowing from the first chamber of the printhead reservoir) are transferred to the second chamber, the bubbles tend to remain on the surface (at the ink level 126) and are highly unlikely to flow downwards to the printhead outlet, which is preferably located at or near the bottom of the printhead reservoir.

[0117] Example of printing system 200 Figure 10 As shown. The printing system 200 includes an ink delivery system 100, a printhead 210, and a recording medium 250. (As illustrated...) Figure 10 As shown, the printing system 200 may include multiple ink delivery systems 100. The ink delivery systems are the same as those referenced above. Figure 1 The ink delivery system is consistent with that in Figure 9. The ink delivery system 100 is configured to supply ink to the printhead 210. The printhead 210 is configured to deposit ink onto the recording medium 250. As described above, the ink delivery system can be configured to move such that the vertical position of the return tank and / or head reservoir changes relative to the vertical position of the printhead. For example, the printing system can be configured such that the ink delivery system can move in the vertical direction or in the longitudinal direction of the ink delivery system. Alternatively or additionally, the printing system can be configured such that the ink delivery system tilts, thereby changing the angle between the longitudinal direction of the ink delivery system and the vertical.

[0118] control system

[0119] The ink delivery system may include a control system configured to set a target heater temperature. The target heater temperature may be set based on ink supply information from the bulk ink delivery system to the oil pan storage tank. Alternatively or additionally, the target heater temperature may be set based on a target ink temperature. Alternatively or additionally, the target heater temperature may be set based on a predetermined maximum ink temperature. The target heater temperature may, for example, be 5°C to 20°C higher than the target ink temperature, preferably 15°C higher, and more preferably 10°C higher.

[0120] Therefore, it is ideal to use a heater to maintain the ink at the target temperature, even when supplying new ink from a bulk ink delivery system in cold conditions. This eliminates the need for a separate online heater to heat new, cold ink to the target temperature. This reduces the risk of unnecessary overheating. Overheating of the ink is desirable, as it damages the ink and wastes energy. Furthermore, heating new ink from ambient temperature to the target temperature using a separate, dedicated online heater would likely require a significant amount of power. Therefore, the system's power requirements can be reduced by placing heaters around the housing along the ink flow path.

[0121] Ink supply information from the bulk ink delivery system to the sump tank may include information about ink being supplied to the sump tank. The control system may be configured to increase the target heater temperature in response to receiving information about ink supply to the sump tank. Optionally, or additionally, the control system may be configured to increase the heater power in response to receiving information about ink supply to the sump tank. As a result, the heater provides more heat when colder new ink is introduced into the ink delivery system. Therefore, the target ink temperature in the sump tank can be maintained.

[0122] The control system can be configured to reduce the target heater temperature in response to receiving information that ink supply to the oil pan has stopped. Optionally, or additionally, the control system can be configured to reduce the heater power in response to receiving information that ink supply to the oil pan has stopped. Optionally, the heater power can be reduced such that no power is supplied to the heater when ink supply to the oil pan has stopped.

[0123] Information regarding ink supply to the oil pan tank may include the amount of ink supplied to the oil pan tank. Furthermore, the ink supply information to the oil pan tank may include the amount of time for which ink is continuously supplied to the oil pan tank. Preferably, the ink supply information to the oil pan tank includes the rate at which ink is supplied to the oil pan tank.

[0124] Information regarding the supply of ink from the bulk ink delivery system to the sump tank can be determined based on monitoring the ink flow through the ink inlet. Optionally, or additionally, information regarding the supply of ink from the bulk ink delivery system to the sump tank can be determined based on the bulk ink system that is ordered to supply ink.

[0125] The heater power and / or target heater temperature can be set based on the ink flow rate into the sump tank. In other words, the control system can be configured to set the target heater temperature or heater power based on the ink flow rate supplied to the sump tank. The target heater temperature or heater power is set to maintain the target ink temperature in the head tank.

[0126] One or more temperature sensors can be installed in the head tank to monitor the temperature of the ink in the head tank. The target heater temperature or heater power can be adjusted based on the ink temperature in the head tank. For example, if the ink temperature in the head tank drops, the target heater temperature can be increased; or, if the ink temperature in the head tank is within a predetermined margin of a predetermined maximum ink temperature, the target heater temperature can be decreased.

[0127] Optionally, or additionally, one or more temperature sensors can be installed in the oil sump tank to monitor the temperature of the ink within the tank. Data on the ink supplied to the oil sump tank can be based on the ink temperature within the tank. Since new ink in the bulk ink delivery system is stored at room temperature, the ink temperature within the oil sump tank will decrease when new ink is supplied. The control system can be configured to increase the target heater temperature in response to the decrease in ink temperature within the oil sump tank.

[0128] Ink supply information from the bulk ink delivery system to the oil pan tank can include a predicted time until the next ink supply from the bulk ink delivery system to the oil pan, based on print data. The control system can be configured to set a target temperature for the heater or the power supplied to the heater based on the predicted time until the next ink supply. Specifically, the control system can be configured to increase the target temperature of the heater in response to the predicted time of the next ink supply being less than or equal to a predetermined time threshold. This prevents the ink in the ink delivery system from dropping too low due to the supply of colder new ink from the bulk ink delivery system, because the heater is controlled to begin heating when new ink is expected to be supplied to the ink delivery system.

[0129] Manufacturing method

[0130] The housing and / or one or more end caps preferably comprise metal, such as aluminum. In particular, the housing preferably comprises a metal tube. The outer wall of the housing is preferably a metal wall, more preferably an aluminum wall.

[0131] according to Figure 1 The manufacturing method of any of the ink delivery systems in Figure 9 may include an additive manufacturing step. Preferably, the additive manufacturing method is selective laser sintering. Preferably, the material used in additive manufacturing is polyamide. The parts formed by additive manufacturing can be chemically smoothed. This can provide the benefits of sealing materials and preventing plastic particles from contaminating the ink.

[0132] Specifically, one or more ridges can be formed using additive manufacturing. Alternatively, all or part of the inner shell can be formed using additive manufacturing. Compared to other manufacturing methods, this method makes it easier to shape one or more ridges into the desired form.

[0133] Furthermore, by using additive manufacturing, it is easier to provide the first end cap and the second end cap, as described above. Figure 6 and Figure 7 For example, filter housings accessible through the end caps of the ink delivery system can be easily formed using additive manufacturing. Similarly, openings can be easily incorporated into the end caps to allow the head tank to vent to the atmosphere. Therefore, this manufacturing method means that a more compact ink delivery system can be provided without increasing manufacturing costs compared to conventional methods.

[0134] Additive manufacturing is cost-effective and makes efficient use of materials. While additive manufacturing is preferred, alternative manufacturing methods can be used due to its cost-effectiveness and adaptability, such as for ridges of different shapes, provided that a suitable ink flow path can be achieved. For example, subtractive manufacturing processes such as milling can be used.

[0135] in conclusion

[0136] Various aspects of the invention have been described with particular reference to the examples shown. While specific examples are illustrated in the accompanying drawings and described in detail herein, it should be understood that the drawings and detailed description are not intended to limit the invention to the specific forms disclosed. It should be understood that changes and modifications can be made to the examples described within the scope of the invention as defined in the claims.

[0137] This application is based on and claims UK priority application GB 2204762.5, filed on 1 April 2022, the entire contents of which are incorporated herein by reference.

Claims

1. An ink delivery system for supplying ink to a printhead, characterized in that, include: An oil pan tank for containing ink, having an ink inlet for receiving ink from a bulk ink delivery system, an oil pan inlet for receiving ink from a printhead, and an oil pan outlet for supplying ink to the printhead tank. The head reservoir is used to contain ink and has a head inlet for receiving ink from the oil pan reservoir and a head outlet for supplying ink to the print head. An ink flow channel is located between the oil pan tank and the head tank. A pump is used to pump ink from the oil pan tank into the head tank through the ink flow channel; An outer casing that houses the oil pan tank, the head tank, and the ink flow channel; the outer casing includes an outer wall for transferring heat to the ink in the ink flow channel, the outer wall including an inner surface defining the surface of the ink flow channel; as well as A heater for heating the outer wall of the housing; An inner shell, disposed within the outer shell, and including an outer surface on the exterior of the inner shell; as well as One or more ridges between the inner shell and the outer shell; wherein the ink flow channel is defined by the inner surface of the outer wall, the outer surface of the inner shell, and the one or more ridges.

2. The ink delivery system according to claim 1, characterized in that, The outer wall also includes an outer surface on the outside of the housing; wherein the heater is used to heat the outer surface of the outer wall.

3. The ink delivery system according to claim 2, characterized in that, The ink flow channel is used to allow the ink in the ink flow channel to contact the inner surface of the outer wall of the housing.

4. The ink delivery system according to any one of claims 2 and 3, characterized in that, The ink flow channel is used to guide ink along an ink flow path between the oil pan outlet and the head inlet; wherein the ink flow path follows an indirect route from the oil pan outlet to the head inlet.

5. The ink delivery system according to claim 4, characterized in that, The ink flow path is spiral or tortuous.

6. The ink delivery system according to claim 5, characterized in that, The oil pan tank and the head tank are housed within the inner shell.

7. The ink delivery system according to claim 5, characterized in that, The inner shell forms the oil pan tank and the head tank.

8. The ink delivery system according to claim 5, characterized in that, The shape of the one or more ridges defines the route of the ink flow path from the oil pan outlet to the head inlet between the inner shell and the outer shell.

9. The ink delivery system according to claim 8, characterized in that, The heater is used to heat the ink in the ink flow channel so that the ink enters the head storage tank at a target ink temperature between 45°C and 55°C.

10. The ink delivery system according to claim 9, characterized in that, The heater is configured to contact the housing in the region extending in the longitudinal direction of the housing between the oil pan outlet and the head inlet.

11. The ink delivery system according to claim 10, characterized in that, The heater is an electric heater.

12. The ink delivery system according to claim 11, characterized in that, The oil pan tank is positioned at the other end of the outer shell, opposite the head tank, in the longitudinal direction of the outer shell.

13. The ink delivery system according to claim 12, characterized in that, The outer shell is cylindrical, and the ink delivery system is used to keep the head tank above the oil pan during use.

14. The ink delivery system according to claim 13, characterized in that, Also includes: A return tank for containing ink, having a return inlet for receiving ink from the printhead, a return overflow inlet for receiving ink from the printhead reservoir, and a return overflow outlet for allowing ink in the return tank exceeding a predetermined threshold level to flow to the oil pan reservoir. The head storage tank includes a head overflow outlet for allowing ink exceeding a predetermined threshold level in the head storage tank to flow to the return tank. The ink delivery system is configured to keep the return tank below the head tank and above the oil pan during use.

15. The ink delivery system according to claim 14, characterized in that, The ink delivery system includes an opening that provides ventilation from the head tank to the atmosphere.

16. The ink delivery system according to claim 15, characterized in that, Also includes: An ink filter is disposed within the housing and is used to filter ink flowing through the ink flow channel.

17. The ink delivery system according to claim 16, characterized in that, Also includes: A control system is used to set the target temperature of the heater based on information about the ink supplied from the bulk ink delivery system to the oil pan.

18. A printing system, characterized in that, include: The ink delivery system according to any one of claims 1 to 17; A bulk ink delivery system for supplying ink to the oil pan tank via the ink inlet; as well as A printhead, wherein the ink delivery system is used to supply ink to the printhead.

19. A method for manufacturing an ink delivery system according to any one of claims 1 to 17, characterized in that, include: Additive manufacturing steps.

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