JP3909802B2 - Printing system with air accumulation control means enabling the use of a semi-permanent print head without air purging - Google Patents

Description

[0001]
Related patents
This application199U.S. Patent Application No. 08/706051 entitled "Printer Using Print Cartridge with Internal Pressure Regulator" filed August 30, 2006, "InkJet Printing System with Off-Axis Ink Supply and High Performance" filed August 19, 1997 U.S. Patent Application No. 08/914832 entitled "Tubing", U.S. Patent Application No. 08/566821 entitled "Self Sealing Fluid Interconnect with Double Sealing Septum" filed Dec. 4, 1995, and filed Feb. 29, 1996. Related to US patent application Ser. No. 08/1608922 entitled “Anti Outgassing Ink Composition and Method for Using the Same”, the entire contents of these patents being incorporated herein by reference. Yes.
[0002]
Background art
The present invention relates to inkjet printers and the like, and more particularly to inkjet printing systems that utilize semi-permanent printheads that do not require an air evacuation mechanism.
[0003]
Inkjet printing systems often utilize an inkjet printhead that is mounted on a carriage that reciprocates across a print medium (such as paper). As the printhead moves across the print media, the control electronics activate the firing portion of the printhead to eject or eject ink drops from the firing nozzles to form an image or character on the print media. An ink supply container supplies ink to the print head ejection portion.
[0004]
Some printing systems utilize ink supply containers that can be replaced separately from the printhead. When the ink supply container is used up, the ink supply container is removed and replaced with a new ink supply container. The printhead is replaced near the end of the useful life of the printhead, not when the ink supply is exhausted. If a replaceable printhead has the ability to utilize multiple ink supply containers, this printhead is called a “semi-permanent” printhead. This is in contrast to disposable print heads that are replaced with each ink container.
[0005]
A major problem with semi-permanent printheads is premature failure due to inadequate pressure regulation. To understand this obstacle, it is necessary to consider the operation of the printhead. In order to operate properly, many printheads have a certain operating pressure range. This is typically -1 and -6 water inches(Ie, -25.4 to -152.4 millimeters)A slightly negative gauge pressure in a narrow range of between must be maintained. Gauge pressure refers to pressure measured relative to atmospheric pressure, and all pressures quoted herein are gauge pressures. When the pressure is positive, printing operations and printing system storage operations are adversely affected. If the pressure becomes positive during the printing operation, ink droplets may drip or drop, causing ejection stop. If the pressure is positive during storage, ink drops will drip off the printhead. Ink that drops during storage accumulates and solidifies on the printhead and printer parts. This stiff ink permanently hinders the droplet ejection of the printhead, resulting in costly printer repairs. In order to avoid positive pressure, the print head utilizes an internal mechanism that maintains negative pressure.
[0006]
Air present in the printhead may prevent such maintenance. When the print head is initially filled with ink, air bubbles are often left there. In addition, air introduced from a number of sources, including diffusive material entering the printhead from outside air and dissolved air exiting the ink, called exhaust air, accumulates over the life of the printhead. During environmental changes such as temperature rise or pressure drop, the air inside the print head expands in proportion to the total amount of air contained. This expansion is against the internal mechanism that maintains the negative pressure. The internal mechanism of the printhead can compensate for these environmental changes for a limited range of environmental catastrophes. Beyond this range, the pressure at the print head becomes positive.
[0007]
One solution to the air accumulation problem has been the use of disposable printheads. The amount of ink on the disposable printhead can be adjusted to keep the air accumulation below a critical threshold. When such an amount of ink is small, printing costs increase due to frequent replacement of the print head. Instead, the ink supply container can be enlarged to reduce the frequency of printhead replacement. However, when the printing application is a compact desktop printer, a large ink supply container becomes a problem. An example of a system that utilizes a disposable printhead in which a large ink supply container is replaced each time the printhead is replaced is described in US Pat. No. 5,369,429 entitled “Continuous Ink Refill System for Disposable Ink Jet Cartridges Having a Predetermined Ink Capacity”. Has been.
[0008]
Another solution to the air accumulation problem has been the use of an air purge mechanism that allows the use of a semi-permanent printhead. An example of an air purge technique is described in US Pat. No. 4,558,326 entitled “Purging System for Ink Jet Recording Apparatus”. For air purge systems, (1) printer cost added for the purge mechanism, (2) reliability issues associated with dealing with ink that tends to drain out with air (this reduces printer maintenance requirements). And (3) (when air is purged via the ink ejection mechanism of the print head) there are problems such as air remaining in the ink ejection mechanism. In particular, the air purge mechanism increases the need for maintenance on the printer.
[0009]
Thus, there is a need for a semi-permanent printhead printing system that uses ink supply technology to enable a low cost, low maintenance, reliable, relatively compact size desktop printer. Yes.
[0010]
Disclosure of the invention
The present invention relates to an inkjet printing system that includes a semi-permanent printhead having a fluid input that receives ink and a discharge portion that ejects ink in response to a control signal. The printing system also includes a replaceable ink supply container configured to provide ink to a printhead that stores a volume of ink. This print head has the ability to operate continuously over the life of multiple volumes of ink. The printing system includes a fluid reservoir that fluidly connects with the print head and the replaceable ink supply container. The fluid reservoir is adapted to contain air introduced into the print head without purging air from the print head during use of the multi-ink refill container.
[0011]
One preferred embodiment of the present invention relates to an ink supply device that fluidly connects to a fluid input and supplies ink to a printhead. The ink supply is adapted to control the air inflow to the print head so that the accumulator can contain all the air introduced during the life of the print head.
[0012]
Embodiment of the Invention
FIG. 1 shows an inkjet printing system 10 of the present invention. Inkjet printing system 10 includes a printhead 12 connected to a replaceable ink supply container 14 via a fluid conduit 16. The printhead 12 receives ink from the fluid conduit 16 and allows the ejection mechanism to selectively eject ink onto a medium (not shown) under the control of the printing system control electronics 20.
[0013]
The fluid conduit 16 receives ink from the replaceable ink supply container 14. The fluid conduit 16 includes a conduit inlet 26 that fluidly connects to a fluid outlet 28 of the replaceable ink supply 14.
[0014]
During the printing operation, ink flows from the ink supply container 14 via the conduit 16 to the print head 12, whereby ink droplets can be ejected by the nozzles (not shown) of the ejection mechanism 18. It becomes. Since the print head 12 is semi-permanent, it has the ability to print large volumes of ink. Accordingly, the ink supply container 14 is periodically replaced. For example, in one embodiment, the printhead is expected to withstand printing of 450 cc of ink. In this embodiment, each ink supply container 14 replenishes the printhead 12 with 30 cc of ink, and thus the printhead 12 is expected to withstand the use of 15 ink supply containers.
[0015]
One aspect of the present invention relates to techniques used to limit air accumulation in a printing system and to store accumulated air. As shown in FIG. 1 and below, the printing system 10 has multiple sources of air that eventually accumulates in the printhead 12.
(l) Initial air—This refers to air bubbles that exist before the printhead 12 is attached to the printing system 10.
(2) Printhead connection—This refers to the air introduced when the printhead 12 is connected to the conduit 16.
(3) Conduit start--This means the air that is initially present in the conduit 16 and flows into the print head 12 when the printing system 10 is first used.
(4) Diffusion—This refers to air that diffuses into the printhead 12 and conduit 16 over the life of the printhead 12.
(5) Ink supply container connection—This means the air introduced when each ink supply container 14 is connected to the conduit 16.
(6) Ink supply container floating air—This means air bubbles present in the ink supply container 14 and finally flowing into the print head 12 via the conduit 16.
(7) Air release—This refers to the air generated by the decomposition of the ink as it passes through the printhead 12.
[0016]
Another aspect of the present invention is an accumulator that allows the print head 12 to contain air that is introduced into the printing system 10 by the source described above. In order to prevent ink from dripping or dropping from the print head 12, it is important that the print head 12 maintain an internal negative pressure. If the print head 12 encounters a significant change in ambient temperature and pressure during periods of no printing, bubbles inside the print head 12 tend to expand and increase the pressure on the print head 12. The printhead includes an accumulator 29 that compensates for such expansion to maintain a negative pressure. However, the storage unit 29 has an upper limit on the amount it can compensate. This is called the “storage capacity” for air.
[0017]
The storage capacity of the storage unit 29 is determined by the design of the storage unit and the environmental operating range. This environmental range is defined by an upper limit temperature and a lower limit pressure at which the storage unit 29 can cope with the maximum bubble expansion. In an exemplary embodiment, this upper limit is a temperature of 140 ° F. at constant pressure.(60 ° C)It is. Therefore, the accumulator is 140 ° F.(60 ° C)Must accommodate an amount of air expansion equal to the storage capacity up to a temperature of In an exemplary embodiment, the storage capacity is 4.5 cc. In other words, this typical accumulator has an outside temperature (about 70 ° F.(21 ° C)) To 140 ° F(60 ° C)Up to 4.5 cc of bubble expansion must be compensated while maintaining the negative pressure in the full space.
[0018]
Another aspect of the invention relates to an “air budget” that is selected to ensure that the source of air does not exceed the storage capacity. Within the air budget, the amount of air allocated to each air source is selected. The following table 1 shows the air budgetOne caseIs shown.
[0019]
[Table 1]
Air budget by source      Air budget value
Initial 0.3cc
Print head connection 0.1cc
Pipe start 1.3cc
Diffusion (conduit, printhead) 1.0cc
Ink container connection 0.1cc
Ink container floating air 0.1cc
Air release 1.6cc
Budget item total = 4.5cc
[0020]
The sum of all budget items is equal to a storage capacity of 4.5 cc. Either budget item can be increased, provided that the other items are reduced accordingly to ensure that the total air budget does not exceed the storage capacity.
[0021]
Another aspect of the present invention relates to techniques used to ensure that each air source is maintained at a low level that can keep the total amount of air stored below the storage capacity level. . A technique for containing air and limiting the introduced air is described below with reference to FIGS.
[0022]
FIG. 2 represents one preferred embodiment of the printing system 10. The printing system 10 includes an input tray 30A and an output tray 30B that store media both before and after media (not shown) is sent to the print area 32, respectively. A carriage 34 supports a plurality of print heads 12 and scans the print area 32 such that a plurality of ejectors 18 associated with the print heads 12 selectively eject ink onto the media. Each print head 12 receives ink from one of a plurality of corresponding ink supply containers 14 via a conduit 16. The print head 12 is semi-permanent because each can use a plurality of ink supply containers 14. For this reason, the printing system 10 can be a compact size. The ink supply container 14 of this preferred embodiment utilizes different pigment inks including black 14b, cyan 14c, magenta 14m and yellow 14y. The black ink supply container 14b has a capacity of about 75 cc, and the color ink supply containers 14c, 14m and 14y each have a capacity of about 30 cc. There is also a 30 cc black ink supply container that is mounted and compatible with a relatively large 75 cc black ink supply container. The size of the ink supply container is selected to be sufficiently small to avoid affecting the size of the printing system 10 and taking into account the service life. At the same time, the size of the container is chosen as large as possible to achieve an acceptable low replacement rate. Since each print head 12 can withstand about 450 cc of ink, it is possible to utilize multiple ink refill containers and are therefore semi-permanent.
[0023]
The storage capacity of the print head 12 will be described below with reference to FIGS. FIG. 3 illustrates an overview of the printhead 12 connected to the fluid conduit 16. The printhead 12 receives ink from the fluid conduit 16 at the incoming pressure and delivers the ink to the ejector 18 at a controlled internal pressure below the incoming pressure. The ejector 18 is fluidly connected to a full space 38 that stores a quantity of ink at a controlled internal pressure. The ink passes through the filter element 39 before reaching the emitter 18 to remove impurities.
[0024]
The negative pressure in the full space 38 is controlled using an adjustment mechanism that includes an actuator 40 and a valve 42. As the ejector 18 ejects ink onto the media, the ink in the full space 38 is depleted. This reduces the internal pressure of the full space 38. When the internal pressure reaches the low pressure threshold, the actuator 40 opens the valve 42 accordingly, causing ink to flow from the fluid conduit 16 into the full space 38. Such introduction of ink raises the pressure in the full space 38. When the internal pressure reaches the high pressure threshold, the actuator 40 closes the valve 42 accordingly. Thus, the pressure in the full space 38 is adjusted between the low pressure threshold and the high pressure threshold.
[0025]
FIG. 4 is an enlarged view of one preferred embodiment of the printhead 12. The printhead 12 includes a fluid inlet 22 for receiving ink from the conduit 16 and an emitter portion 18 that selectively ejects ink onto a medium (not shown). The print head 12 also includes an internal adjustment mechanism. The internal adjustment mechanism includes an air conduit 43 which will be described later with reference to FIG.
[0026]
5A, 5B, and 5C are cross-sectional views of the print head 12 of FIG. 4 viewed from the direction of reference numeral 5A. In order to more clearly illustrate the functional aspects of the pressure regulation system of the print head 12, the internal configuration of the print head 12 has been simplified. The same reference numbers are used to identify the same elements when comparing FIG. 3 and FIG.
[0027]
The printhead 12 includes an outer enclosure 44 that supports the emitter portion 18. The full space 38 is in fluid communication with the emitter portion 18. Inside the filling space 38 is an actuator 40 and a valve 42 for selectively allowing ink to flow into the filling space 38.
[0028]
The valve 42 includes a nozzle 46 that fluidly connects to the fluid inlet 22 to allow ink to flow into the full space 38 and a valve seat 48 that seals the nozzle 46. The valve seat 48 is formed of an elastic material that can ensure a reliable sealing of the valve 42. The valve seat 48 is fixedly attached to a pressure adjusting lever 50 that rotates with respect to the adjusting axle. As shown in FIGS. 5A to 5C, the rotation of the lever 50 opens and closes the valve 42 based on a change in pressure in the full space 38.
[0029]
The print head 12 also includes a storage lever 52 that rotates relative to the storage lever axle 52A. A spring 54 connects the regulating valve lever 50 and the accumulation lever 52 to bias both levers relative to each other. The spring is connected relatively closer to the accumulator axle than to the adjustment axle 50A.
[0030]
An inflatable bag 56 is disposed between the accumulation lever 52 and the adjustment lever 50. The first surface of the inflatable bag 56 contacts the atmosphere via an air conduit, and the second surface of the bag 56 contacts the ink in the full space 38. Thus, the bag 56 expands and contracts in response to the pressure difference between the full space 38 and the atmosphere. The bag 56, adjusting lever 50 and spring 54 perform the same function as the actuator 40 described above with reference to FIG.
[0031]
FIG. 5A shows an initial state of the print head 12 in which the bag 56 is completely deflated. When printing begins, the bag 56 is inflated to compensate for the amount of ink ejected by the ejector 18. The volume of the bag increases and begins to push the accumulation lever 52 on one side and the adjustment lever 50 on the other side against the force created by the spring 54.
[0032]
When the pressure in the bag 56 is sufficiently high, both levers begin to pivot in the opposite outward direction. Since the moment generated by spring 54 on accumulation lever 52 is less than the moment generated by spring 54 on adjustment lever 50, accumulation lever 52 first begins to move. The accumulation lever moves until it contacts the outer enclosure 44, as shown in FIG.
[0033]
When the accumulation lever 52 is fully extended, the adjustment lever 50 begins to move, and finally the valve seat 48 is lifted away from the nozzle 46, as shown in FIG. open. Accordingly, ink flows from the conduit 16 through the nozzle 46 into the full space 38. Inflowing ink increases the pressure in the full space 38 and reduces the force of the bag 56 against the leverage 50, 52 so that the valve 42 is closed. As a result, the print head 14 is in a state as shown in FIG.
[0034]
As mentioned above, it is important that a negative pressure be maintained in the full space 38. The accumulator functions to maintain this negative pressure even when air is present in the full space 38. Due to the relative mounting position of the spring 54, the accumulator lever remains pressed against the enclosure 44 during normal operation. As the printhead usage period proceeds, air bubbles 58 tend to accumulate on the printhead 12. During storage and hibernation of the printing system 10, the temperature of the environment can change. According to the ideal gas law, the bubble 58 expands in response to the temperature rise and the bag 56 deflates accordingly. As the bag 56 is deflated, the accumulator leverage 52 moves to maintain pressure on the bag 56.
[0035]
Thus, the accumulator lever 52 and the bag 56 ensure a constant negative pressure in the print head 12 and prevent positive pressure throughout the range of movement of the accumulator lever.
[0036]
In a typical system, the range of motion of the accumulator 52 is such that the air accumulated in the full space 38 can be stored up to a storage capacity of 4.5 cc while maintaining the negative pressure of the full space 38 over a specified environmental operating range. Allow. If the accumulated air exceeds 4.5 cc, ink drips from the printhead 12, causing printhead and printer failure, and affecting the operation of the emitter 18. Thus, the cumulative amount of all air sources must be kept below a storage capacity of 4.5 cc.
[0037]
There is another form having a pressure regulator and an accumulator. Referring again to FIG. 3, the valve 42 may be an electromechanical valve such as a solenoid valve. Actuator 40 may be a pressure transducer that sends a signal to a circuit for opening and closing valve 42. In order to provide a capacity for storing air, the outer wall of the full space 38 must be at least partially flexible. One means of doing so comprises a rubber divider 60 that can decouple the filled space 38 from the atmosphere and move in response to air bubble expansion. The partition plate 60 performs the same function as the storage unit 29. Alternatively, the full space 38 can be surrounded by a spring-loaded bag that performs the same function as the storage portion 29. Each alternative storage design has its own air accumulation limit and storage capacity. In order to avoid the harmful effects of positive pressure, the sum of the air sources must be kept below this storage capacity.
[0038]
The air sources and the techniques used to keep them within their respective budget ranges are described below with reference to FIGS. It is an important aspect of the present invention to allocate and control the budget to each source to achieve the overall budget goal.
[0039]
The first source of air is the air that is initially present in the print head 12 before the print head 12 is attached to the printing system 10. In one exemplary embodiment, the budget allocated for this source is 0.3 cc of air, which is the air introduced by the manufacturing process, which diffuses into the print head 12 during manufacturing and installation. And air flowing into the print head 12 through the fluid inlet 22 or the emitter portion 18. In order to minimize these values, a number of design and assembly methods are utilized for manufacturing the printhead 12, as described below.
[0040]
When the print head 12 is manufactured, air is introduced when the print head 12 is filled with ink. To minimize such air, the following ink filling process is used. (1) By applying a source of C02 gas to the fluid inlet 22 and applying a vacuum source to the emitter 18 of the printhead 12 until almost all of the gas present in the printhead 12 is composed of C02, C02 gas is initially fed into the print head 12. (2) The print head 12 is then degassed by applying a source of ink that has been degassed to the fluid inlet 22 until the print head 12 is filled with ink, and a vacuum source to the emitter 18 respectively. That is, the dissolved oxygen is filled with an ink that is less than the saturation level. The bubbles left during the filling process consist mainly of C02, which immediately dissolves in the ink. Furthermore, since the gas has been removed from the bubbles, impurities in the bubbles (such as air) are absorbed by the ink.
[0041]
The printhead 12 is also manufactured with a high air diffusion barrier material to minimize air diffusing during the ink filling process and attachment of the printhead 12 to the printer. In a preferred embodiment, the outer enclosure 44 of the print head 12 is made of LCP (Liquid Crystal Polymer). Other high barrier materials such as PET (polyethylene terephthalate) or metallized plastics also work effectively. The bag 56 is preferably formed from a multi-layered plastic thin film with at least one layer having high air diffusion barrier properties. One preferred high barrier material is PVDC (polyvinylidene chloride). Other layers such as LDPE (low density polyethylene) can also be utilized to maximize tack and flexibility.
[0042]
As shown in FIGS. 6 and 7, a second air source is introduced when a “printhead connection” is established between the conduit outlet 24 and the fluid inlet 22. FIG. 6 shows the initial attachment of the print head 12 to the carriage 34. The print head 12 is attached to the carriage 34 by insertion with a substantially downward movement. With insertion, the conduit outlet 24 connects to the fluid inlet 22 of the printhead 12. Details of the fluid connection between the fluid inlet 22 and the conduit outlet 24 are shown in FIGS. 7 (A)-(C). FIG. 7A shows the print head 12 in a position to make a fluid connection to the conduit outlet 24. FIG. 7B shows the conduit outlet 24 prior to fluid connection. FIG. 7C shows the completed fluid connection between the fluid inlet 22 and the conduit outlet 24.
[0043]
The fluid inlet 22 of the print head 12 includes a hollow needle 62 extending downward with a closed blunt lower end, an inner diameter not shown from the outside (not shown), and a lateral hole 66. The inner diameter fluidly connects to the nozzle 46 and to the lateral bore 66 as shown in FIGS. The needle 62 is surrounded by a wind guide plate 68.
[0044]
The conduit outlet 24 includes a hollow cylindrical containment 70 extending upward. The hollow containment 70 has an inlet 72 that is in fluid communication with the conduit 16. The hollow container 70 has an upper end that supports a pre-slit partition 74 secured to the container 70 by a bent cap 76. A sealing member 78 is pressed against the partition wall 74 by a spring 80.
[0045]
When the print head 12 is attached to the carriage 34, the air guide plate 68 serves to align the partition wall 74 with the needle 62. The upper end of the conduit inlet 24 is sized to properly engage the fluid inlet 22. The diameter of the upper end of the conduit inlet 24 must be small so that it can be accommodated by the baffle plate 68 and is large enough to control the change in placement between the fluid inlet 22 and the conduit outlet 24. Must. Such a configuration ensures a reliable fluid connection between the needle 62 and the septum 74. During fluid connection, the needle 62 pushes the sealing member 78 down into the cylindrical container 70. In this manner, in the final insertion position, ink flows from the conduit 16 through the reservoir inlet 72, around the sealing member 78, into the lateral hole 66, the inner diameter 66, and further to the nozzle 46 (FIG. 7).
[0046]
In order to remain within the air budget, it is important that the fluid disconnect and reconnection between the conduit outlet 24 and the fluid inlet 22 introduce a minimal amount of air to the printhead 12. If the printhead 12 is disconnected from the conduit 16, negative pressure may exist in the conduit 16. Negative pressure tends to draw air into the conduit outlet 24. To prevent this, the septum 74 self seals immediately after the needle 62 is retracted, preventing air from entering the conduit 16. However, as the period of use proceeds, the septum 74 may contract and the septum 74 may not immediately self-seal after the needle 62 is retracted. Seal member 78 provides a redundant seal of conduit outlet 24 to ensure a quick and reliable seal. Although the air budget in Table 1 allocates 0.1 cc of air for this fluid disconnect and reconnect, the actual air introduced with respect to the printhead 12 is large due to the reliable self-sealing characteristics of the conduit outlet 24. Absent.
[0047]
A third source of air is air called “conduit start” that is present in the conduit 16 when the printhead 12 is initially installed. In one exemplary embodiment, this provides the printhead 12 with less than 1.3 cc of air. Returning to FIG. 1, the fluid conduit 16 is initially emptied to address reliability issues. For example, during manufacturing and shipment to a customer, the printing system 10 may experience temperature fluctuations that can cause ink solidification and expansion (damaging the fluid conduit 16) in the fluid conduit 16. For this reason, the fluid conduit 16 is initially shipped from the factory in a dry state.
[0048]
A fourth source of air is air diffusion that enters the print head 12 and conduit 16 while the print head 12 is attached to the printing system. In one exemplary embodiment, the total amount of diffusion is kept below 1.0 cc by using high air diffusion barriers for printhead and conduit manufacturing. As described above, the print head is made of a highly diffused barrier polymer. The fluid conduit is 100 cc · mil / (100 in at a temperature of 23 ° C. and a relative humidity of 0%.²• Includes tubes made of low air diffusion materials with oxygen permeability characteristics of day / atm). Examples of flexible polymers suitable for this tube include PVDC (polyacrylic ester vinylidene chloride copolymer), ECTFE (ethylene chloro trifluoro ethylene) and PCTFE (polychloro trifluoro ethylene) copolymers.
[0049]
As shown in FIGS. 8 and 9, the fifth air generation source is an ink supply container connection between the ink supply container 14 and the conduit 16. FIG. 8 shows the ink supply container 14 in a position ready for downward insertion into the receiving station 36. Details not relevant to the present invention are omitted. Ink supply container 14 includes a fluid reservoir 82 in fluid connection with fluid outlet 28. As the ink supply container 14 is inserted into the receiving station 36, the fluid outlet 28 connects to the conduit inlet 26 and ink flows from the fluid reservoir 82 to the conduit 16 and the printhead 12.
[0050]
Further details of the ink supply container connection are shown in FIG. 9, which is an enlarged view of the ink supply container of FIG. 8 taken from 9A-9A, showing only the fluid connection. FIG. 9A shows the fluid outlet 28 and conduit inlet 26 prior to fluid connection.
[0051]
The fluid outlet 28 of the ink supply container 14 includes a hollow cylindrical protrusion 84 that extends downward from the ink supply container chassis 86. The hollow projection 84 has an upper end that fluidly connects with the reservoir 82 and a lower end that supports a pre-slit septum 88 secured to the projection 84 by a bent cap 90. The sealing member 92 is pressed against the partition wall 88 by a spring 94.
[0052]
The fluid inlet 26 includes an upwardly extending hollow needle 96 having a closed, blunt upper end, an inner diameter not shown from the outside (not shown), and a transverse hole 98. The inner diameter fluidly connects to the transverse hole 98. The end of the needle 96 opposite the lateral hole 98 is fluidly connected to the conduit 16 for supplying ink to the printhead 12.Sliding ring100 surrounds the needle 96 and includes a flexible portion 102.Sliding ring100 is biased upward by a spring 104 so that the flexible portion 102 maintains a position that seals the lateral hole 98 from the atmosphere.
[0053]
The conduit outlet 26 is alsoSliding ring100 includes a protrusion 105 that surrounds 100 and extends upward. The upwardly extending protrusion 105 provides a holding force for sliding the annular tube 100 to the needle 96 and provides an alignment function for the fluid outlet 28.
[0054]
FIG. 9B shows the fluid connection between the fluid outlet 28 and the conduit inlet 26. When the ink supply container is attached to the receiving station, the lower or distal end of the fluid outlet 28 is first guided into engagement with the inclined portion 105a and the inner surface 105b of the protrusion 105 and aligned with the needle 96. Next, the lower end of the fluid outlet 28 isSliding ringPress 100 down. At the same time, the needle 96 enters the partition wall 88 and passes through the partition wall 88 to push up the sealing member 92 to the cylindrical protrusion 84. In this way, in the fully inserted position, ink passes from the ink reservoir 82, through the protrusion 84, around the sealing member 92, to the lateral hole 98, to the fluid conduit 16, and to the print. It flows into the head 12.
[0055]
Upon removal of the ink supply container 14, the septum 88 is withdrawn from the hollow needle 96, allowing the fluid outlet 28 and conduit inlet 26 to return to the state shown in FIG.
[0056]
The fluid outlet 28 is sized to reliably engage the fluid inlet 26 so as to avoid inflow of air into the conduit 16. The fluid outlet 28 ensures a connection between the lateral hole 98 and the interior of the hollow projection 84,Sliding ring100 correctly meshed,Sliding ringThe length must be such that 100 can be pushed far enough away from the lip 105c. The diameter of the lower end of the fluid outlet 28 must be small so that it can be accommodated in the projection 105, but the positional variation between the hour hand 96 and the partition wall 88 engaging the inclined portion 105a and the inner surface 105b of the projection 105 can be controlled. Must be such a size.
[0057]
Since a plurality of ink supply containers are connected and disconnected from the conduit inlet 26, a minimum amount of air is introduced into the conduit 16 by fluid disconnection and reconnection between the conduit inlet 6 and the fluid outlet 28. Is important. When the ink supply container 14 is disconnected from the conduit 16, there may be a slight negative pressure in the conduit 16 that tends to draw air into the conduit inlet 26. To prevent this, when the ink supply container 14 is disconnected,Sliding ringImmediately seals the lateral hole 98. On the fluid outlet side, the partition wall 88 and the sealing member 92 are immediately self-sealing to prevent air from flowing into the ink supply container 14. This is important if the ink supply container 14 is disconnected and reconnected to prevent air introduction. The air budget in Table 1 only allocates 0.1 cc of air for the connection of the ink supply container 14 over the life of the print head 12.
[0058]
The sixth air generation source is “ink supply container floating air” or air bubbles in the ink supply container 14, which flows from the ink supply container 14 into the print head 12 via the conduit 16. This floating air is initially present in the reservoir 82 and the fluid outlet 28. In one preferred embodiment, the ink supply container 14 is mounted in a substantially vertical direction, as shown in FIG. All floating air tends to actively rise to the upper part of the ink supply container 14. In such a configuration, the contribution of the “ink supply container floating air” to the air budget is 0.1 cc.
[0059]
However, if there is sufficient floating air in the ink supply container 14, such air may be sent to the conduit 16 when the ink in the ink supply container 14 is almost depleted. Thus, it is desirable to limit the total amount of air bubbles that can accumulate in the ink supply container 14.
[0060]
Ink supply container floating air is affected primarily by the ink supply container material and the manufacturing process. FIGS. 10 and 11 are an exploded view and a fully assembled view of one preferred embodiment of the ink supply container 14. Details not associated with the present invention are omitted. Referring to FIG. 10, the assembly of the ink supply container 14 includes the following steps.
[0061]
1. Prepare a chassis 86 that includes an outwardly extending fluid outlet projection 84 and a peripheral sealing surface 106.
[0062]
2. Adhere and seal the film lamina 108 to the peripheral sealing surface 106 to form the reservoir 82. The film sheet has a high air diffusion partition multiple laminated structure. In a preferred embodiment, the layers comprise nylon (PET) and LDPE coated with metal (silver).
[0063]
3. The spring 94, the sealing member 92, the pre-slit partition wall 88, and the bent cap 90 are assembled to the protrusion 84 to form the fluid outlet 28.
[0064]
4. Fill the ink supply container with CO2 by jetting CO2 into the fill port 110 and venting air from the fill port 110. This CO2 injection and venting process is repeated until substantially no air remains in the reservoir.
[0065]
5. After removing air from the filling port 110, the ink supply container is filled with the ink deaerated through the filling port 110.
[0066]
7. Place the ink supply container into the cap 112 and the shell 114. The ink supply container 14 assembled in this way is shown in FIG.11Is shown in
[0067]
The process described above minimizes the airborne air that initially exists and accumulates from two main perspectives. First, as described above with respect to the printhead 12, the CO2 inflow and degassing filling process purges the initial airborne air present in the ink supply container. Second, the material selection for the film lamella 108 minimizes the diffusion of air into the fluid reservoir 82 and keeps the accumulated air at the beginning of the flow of air into the conduit 16 below a threshold. .
[0068]
The seventh source of air accumulation in the print head 12 is air release. This air release mechanism is a solubility change that occurs as ink passes through the full space 38 of the print head 12. As the ink enters the full space 38, the solubility of the dissolved air in the ink decreases, so that air diffused from the ink becomes bubbles in the full space 38. As further explained below, this solubility decrease is primarily induced by temperature.
[0069]
FIG. 12 is a solubility curve for water and plots the solubility of air in water with respect to the water temperature. As can be seen from the curve, the solubility of water decreases with increasing temperature. The thermal ink-jet ink associated with the present invention is based at least in part on water. Thus, in many cases, such inks tend to have an air solubility curve having a shape similar to that illustrated in FIG.
[0070]
When the print head 12 is operating, the emitter portion 18 warms the ink in the full space 38. Therefore, the ink near the ejector portion 18 exceeds the saturation state with respect to the air, and as a result, the air diffused from the ink becomes bubbles in the full space 38, and the size of the bubbles increases.
[0071]
One means of reducing the amount of released air is to include an anti-air releasing additive that has the effect of reducing the slope of the solubility curve and thus reducing the air release rate. A preferred additive having such an effect is ethoxylated glycerin. However, there are various other anti-air releasing additives suitable for the present invention, including 2-pyrrolidone, N-methyl pyrrolidone, ethylene glycol, 2-propanol, 1-propanol, cyclohexanol, EHPD. .
The following list shows further additives.
(a) Ketones or keto alcohols such as acetone, methyl ethyl ketone and diacetone ether.
(b) An ether such as dioxane.
(c) Esters such as ethyl acetate, ethyl lactate, ethylene carbonate and propylene carbonate.
(d) Diols such as 1,4 butanediol, 1,2 pentanediol, 1,5 pentanediol and 1,2 hexanediol.
(e) Polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol / glycerin and thiodiglycol.
(f) Relatively low alkyl monoethers or diethers derived from alkylene glycols such as diethylene glycol monomethyl (or ethyl) ether and tetraethylene glycol monomethyl (or ethyl) ether.
[0072]
Desirably, the anti-air release additive, one of the above elements or mixtures thereof, is present in a weight range of at least 2%, preferably 12% or more. The following are examples of inks with controlled air release characteristics.
[0073]
component       weight%
Anti-air release additive 12
(Ethoxylated glycerin, etc.)
Colorant 6
(C.I Direct Black 52)
Ink medium 80
(Water plus additional solvent)
Additional combination component 2
(E.g. killing agents, surfactants, bleed control agents, buffering agents, etc.)
[0074]
The above exemplified black ink has an average gradient of tangent to a solubility curve that decreases between about 25 ° C. and 60 ° C. to about 1/2 or less than water. In other words, the change in air solubility in the ink between 25 ° C. and 60 ° C. is reduced to about half of the change expected for water with the addition of additive. As a result, typical black inks containing such additives have an air release rate that is reduced to less than half of the air release rate of water. This produces results that contribute to an air budget of 1.6 cc.
[0075]
One side of the ink supply container 14 that increases the air release rate is the ink high pressure sealing method. For printing systems that require high ink flow rate printing, a high pressure sealing method is typically implemented to eliminate the effect of pressure drop between the reservoir 82 and the print head 12. Referring to FIG. 11, one preferred embodiment of the ink supply container 14 includes a high pressure sealing means 116 associated with the ink supply container 14. The high-pressure sealing means 116 is a pump that is integrated with the ink supply container 14. Alternatively, the high pressure sealing means 116 is an air inlet that fluidly connects with the area surrounding the reservoir 82. A source of pressurized gas is connected to the high pressure sealing means 116 to pressurize the ink contained in the reservoir 82. In either case, the high pressure sealing means provides ink pressurized at the fluid outlet 28.
[0076]
The high pressure sealing method increases the solubility of gas in the ink contained in the ink supply container 14 through the Henry method. If a constant pressure is applied, the ink will gradually saturate with air over time, and the ink air release rate will increase during the movement of the printhead 12. One way to reduce dissolved air is to use the high pressure sealing means 116 as an intermittent pressure source to pressurize ink that is sent to the conduit 16 only when needed for printing, and the printing system 10 is normally at rest. The time is to release the pressure at the fluid outlet 28. This minimizes the portion of the air release contributed by the high pressure sealing method, as most of the time is spent as non-printing time.
[0077]
Thus, various air accumulation sources and various techniques for maintaining air accumulation within budget are described. These are summarized in Table 1 for a typical printing system. The sum of these sources for a typical system is about 4.5 cc. If the sum of these sources exceeds 4.5 cc, a pressure adjustment failure may occur and ink in the print head 12 may leak into the printing system.
[0078]
A printing system in which the fluid conduit 16 is fluidly connected to decouple the fluid outlet 28 and the fluid inlet 22 has been described above. FIG. 13 shows an alternative ink supply container 14 ′ that is mounted to connect directly to printhead 12 ′ in a “carriage mounted” configuration. Ink supply container 14 'includes a fluid outlet 28' connected directly to fluid inlet 22 'of printhead 12'. Such a configuration eliminates the need for a conduit 16 disposed therebetween. This eliminates some of the main air sources including one of conduit startup, conduit diffusion and fluid connections. This will have the effect of increasing printhead life or otherwise reducing the required air storage capacity.
[0079]
Another alternative is to provide the ink supply container 14 'with a pressure adjustment function and storage function instead of the print head 12'. This will tend to simplify the overall fluid delivery system, at the expense of precise pressure control at the printhead 12 '.
[0080]
The present invention includes the following embodiments as examples.
(1) An ink jet printing system of a type having a replaceable ink supply container for supplying ink to a print head,
A semi-permanent inkjet printhead having a fluid input for receiving ink and a discharge portion for selectively ejecting ink in response to control signals and capable of printing a plurality of ink volumes;
A replaceable ink supply container configured to store one of a plurality of ink volumes and supply ink to the inkjet printhead;
Fluid to inkjet printhead and replaceable ink supply container To the inkjet printhead to maintain a printhead pressure range within an operating range that allows the printhead to print multiple ink volumes without purging air from the inkjet printhead. An accumulator for compensating the introduced air;
An inkjet printing system comprising:
(2) The print head is
An internal filling space fluidly connected to the discharge part;
A regulator valve having a function of receiving ink from a fluid input and supplying ink to the full space, and opening and closing in response to a pressure change in the full space in order to maintain a specified negative pressure in the full space;
The inkjet printing system according to (1), further comprising:
(3) The print head includes an internal filling space fluidly connected to the discharge portion, and the fluid storage portion has a first surface that contacts the outer atmosphere and a second surface that contacts the ink in the internal filling space. The inkjet printing system according to (1), including a flexible member, wherein the flexible member contracts in response to bubble expansion in order to maintain a negative internal pressure in the full space.
(4) The inkjet printing system according to (1), further including a fluid conduit fluidly connected to the print head at one end and the fluid input portion at the other end.
(5) The inkjet printing system according to (1), wherein the semi-permanent print head is capable of printing over the life of at least five ink supply containers.
[0081]
(6) An inkjet printing system comprising: a replaceable ink supply container that supplies a supply volume of ink to the printhead; and a printhead having an emitter portion that emits droplets of ink in response to a control signal. And
The printhead includes a fill space for supplying ink to the emitter portion and a valve for providing a one-way ink flow from the replaceable ink supply container to the printhead;
The valve opens and closes in response to a pressure change in the full space to maintain a specified negative pressure in the full space;
The filled space contains accumulated air that increases with the use of each replaceable ink supply;
An ink jet printing system, wherein the print head includes an accumulator that compensates for the expansion of accumulated air to maintain a negative pressure range of the full space.
(7) The inkjet printing system according to (6), wherein the valve includes a nozzle that sends ink to a full space and a valve sheet that seals the nozzle to stop the flow of ink to the full space.
(8) The inkjet printing system according to (7), wherein the valve seat is attached to a lever that is attached so as to be able to turn.
(9) The fluid accumulation unit includes a flexible member having a first surface that comes into contact with the outside atmosphere and a second surface that comes into contact with ink in the internal filling space, and the flexible member maintains a negative internal pressure in the filling space. Therefore, the inkjet printing system according to (6), which contracts in response to bubble expansion.
(10) The inkjet printing according to (9), wherein the full space has a negative internal pressure that gives a bias force to the flexible member, and the bias force opens the valve when the bias force exceeds a certain threshold value. system.
[0082]
(11) A printing system comprising a replaceable printhead, a fluid conduit and a replaceable ink supply container,
An emitter portion having the ability to print a plurality of ink volumes without purging air from the replaceable print head, and ejecting droplets of ink in response to a control signal; and An internal filling space to be connected; an accumulator that compensates for the expansion of air accumulated in the filling space; and a fluid inlet that is fluidly connected to the filling space to supply ink to the filling space;
The fluid conduit has a self-sealing conduit outlet configured to fluidly connect to the fluid inlet to prevent air from entering the fluid outlet when the conduit outlet is removed from the fluid inlet. The conduit outlet is self-sealing and the fluid conduit is self-sealing conduit inlet Including
The replaceable ink refill container has a fluid outlet configured to fluidly connect to the conduit inlet, the conduit to prevent air from entering the fluid inlet when the conduit inlet is removed from the fluid inlet. A printing system, wherein the inlet is self-sealing, and wherein the replaceable ink supply container includes a fluid reservoir fluidly connected to the fluid outlet and including one of a plurality of ink volumes.
(12) The fluid conduit is 100 cc · mil / at a temperature of 23 ° C. and a relative humidity of 0%. ( 100 in ² ・ day ・ atm) The printing system according to (11), including a portion formed of a high air barrier material having oxygen permeable characteristics.
(13) The high air barrier material is a polymer selected from the group consisting of polyacrylate vinylidene chloride copolymer, ethylene, chloro, trifluoro, ethylene, and polychloro, trifluoro, ethylene, (12) The printing system described in.
(14) further comprising a valve disposed between the fluid outlet and the full space, fluidly connected therewith, and opened and closed in response to a pressure change in the full space to maintain a specified negative pressure in the full space; The printing system according to (11).
[0083]
(15) A semi-permanent printhead having an ejector portion that ejects ink in response to a control signal, having a capability of printing a plurality of ink volumes, and including a fill space fluidly connected to the emitter portion. A device for supplying ink to a printing system comprising: the internal filling space has a negative internal pressure to prevent printhead failure and has a maximum storage capacity in the full space while maintaining the negative internal pressure A reservoir configured to expand and contract to contain air, and further fluidly connect to a self-fluidic sealing connection device;
A reservoir that is removably attached to the printing system and stores one of a plurality of ink volumes;
A fluid outlet fluidly connected to the reservoir and configured to fluidly connect to the fluid connection device when the reservoir is connected to the printing system;
With
When the reservoir is connected to the printing system, ink flows from the reservoir through the fluid outlet to the filled space, where floating air and dissolved air in the ink are brought into the filled space for storage. The ink supply device is configured to accumulate less than stored air during the life of the printhead without the reservoir, fluid outlet and ink purging air from the printing system.
(16) The accumulation unit includes a flexible member having a first surface in contact with the outside atmosphere and a second surface in contact with the ink in the internal filling space, and the flexible member maintains a negative internal pressure in the filling space. The ink supply device according to (15), wherein the ink supply device contracts according to bubble expansion.
(17) The printhead is fluidly connected to the filled space and the fluid outlet and is responsive to pressure changes in the filled space to maintain a negative pressure range in the filled space that ensures proper operation of the discharge portion. The ink supply device according to (15), including a valve that opens and closes.
(18) When the fluid outlet is connected to and disconnected from the fluid connection device . The ink supply device according to (15), which is adapted to introduce less than 02 cc of air.
[0084]
(19) wherein the fluid connection device includes an outlet hole and includes a needle surrounded by a sliding ring, the fluid outlet being configured to engage the needle and the sliding ring to move the sliding ring from a sealed position; The ink supply device according to (15), wherein the ring seals the outlet hole fluidly connected to the fluid outlet at an unsealed position.
(20) The needle and sliding ring are surrounded by a cylindrical protrusion, and the fluid outlet is formed into a cylindrical protrusion while allowing alignment and proper fluid connection between the needle and the distal end of the fluid outlet. The ink supply device according to (19), which is sized to be stored.
(21) The ink supply device according to (15), wherein the ink includes an additive that makes the air release rate lower than the air release rate of water.
(22) The ink supply apparatus according to (21), wherein the additive has a concentration of at least 2 percent by weight of the ink.
(23) The ink supply device according to (22), wherein the additive has a concentration of at least 10 percent by weight of the ink.
(24) The printing system is disposed between a first end fluidly connected to the full space, a second end fluidly connected to the self-sealing fluid connection device, and the first Ink supply according to claim 15, comprising a fluid conduit having a flexible portion allowing one end to scan with the print head and the self-sealing connection device stationary with respect to the print head apparatus.
(25) The ink supply device according to (15), wherein the self-sealing connection device scans together with a print head.
[0085]
(26) A print head including an ejector portion that ejects ink in response to a control signal, an internal filling space that supplies ink to the ejector portion, and an ability to print a plurality of ink volumes; and An ink supply apparatus that fluidly connects to a full space and supplies ink to a printing system comprising a fluid input associated with the printhead,
The ink supply device comprises:
A fluid outlet fluidly connected to the fluid input;
A fluid reservoir that is fluidly connected to the fluid outlet and capable of storing one of a plurality of ink volumes;
With
The fluid reservoir and the interior filled space are fluidly connected to form an ink supply system for the emitter portion when the fluid outlet fluidly connects to the fluid input;
The ink supply system contains air introduced into the ink supply system to allow the print head to print multiple ink volumes without purging air from the inkjet print head. An ink supply device including a fluid storage unit to be applied.
(27) The ink supply system further includes a regulator valve that fluidly connects the fluid reservoir to the printhead, the regulator valve being adapted to the emitter The ink supply device according to (26), wherein the ink supply device opens and closes in response to a pressure change in the internal filling space in order to maintain a pressure region enabling operation.
(28) The ink supply device according to (26), wherein the fluid accumulation unit is integrally incorporated in the print head.
(29) The ink supply device according to (26), wherein the fluid accumulation unit is integrally incorporated in the fluid reservoir.
(30) The fluid reservoir as described in (29), wherein the fluid accumulator performs an accurate pressure adjustment that ensures supply of ink to the emitter portion having an operating pressure range that allows proper operation of the emitter portion. Ink supply device.
(31) The ink supply device according to (26), wherein the device is an ink supply container containing ink that can be supplied between 10 cc and 100 cc.
[0086]
(32) a semi-permanent printhead comprising a fluid input for receiving ink, an emitter portion for ejecting ink drops onto the medium, a fill space having an initial air accumulation and delivering ink to the emitter portion, and an accumulation portion An ink supply method for a printing system, comprising:
While the first volume of ink is being supplied to the ejector portion, the first volume of the supplyable ink is fluidized to the fluid input while adding a first volume of air to the full space. Connecting to
Compensating for the initial and first volume of air accumulated in the print head to maintain the print head at a negative pressure within an operating pressure range;
While the second volume of ink is being supplied to the emitter portion, the second volume of the supplyable ink is fluidized to the fluid input while adding a second volume of air to the full space. Connecting to
Compensating for the initial, air expansion of the first and second volumes of air accumulated in the printhead to maintain the printhead at a negative pressure within an operating pressure range;
An ink supply method comprising:
(33) The ink supply method according to (32), further including a step of opening / closing an adjustment valve in response to a pressure change of the print head in order to maintain a negative pressure in the print head.
(34) The accumulating portion has a first surface in contact with the outside atmosphere and a second surface in contact with the full space, and the full space tends to attract the second surface to the full space. The ink supply method according to (32), wherein pressure is applied to the second surface in proportion to the negative pressure in the full space.
(35) The print head further includes an accumulator lever that applies a lever force against the pressure to the second surface, and the accumulator expands and contracts according to the accumulated air expansion. The ink supply method according to (34), wherein the accumulation lever is swiveled following the movement of the second surface.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a printing system of the present invention and also showing sources of air that affect the printing system.
FIG. 2 is a perspective view of one preferred embodiment of a printer utilizing the present invention.
FIG. 3 is a block diagram of one preferred embodiment of the printhead of the present invention.
FIG. 4 is an enlarged view of one preferred embodiment of the printhead of the present invention.
5 is an enlarged block diagram of the print head of FIG. 4 as viewed from 5A-5A.
FIG. 6 is a block diagram illustrating the print head in a position to be inserted into the carriage portion of the printing system of the present invention.
7A is a block diagram illustrating a printhead in a posture connected to a conduit outlet of the present invention, FIG. 7B is a cross-sectional view of the conduit outlet, and FIG. 7C is a printhead and conduit outlet. FIG. 6 is a cross-sectional view illustrating a fluid connection between the two.
8 is a block diagram illustrating an ink supply container storage station of the type used in the printing system of FIG. 2 with an ink supply container in a position for insertion into the ink supply container storage station.
9A is a cross-sectional view of the fluid outlet and conduit inlet prior to the fluid connection between the fluid outlet and the fluid inlet, and FIG. 9B is a cross-sectional view of the fluid outlet and conduit inlet after the fluid connection. FIG.
FIG. 10 is an enlarged block diagram prior to assembly of parts of the ink supply container of one preferred embodiment.
FIG. 11 is a block diagram of one preferred embodiment ink supply container.
FIG. 12 is a graph showing the solubility of air in water with respect to temperature.
FIG. 13 is a block diagram illustrating an ink supply container and a print head in an alternative embodiment of the present invention.
[Explanation of symbols]
10 Inkjet printing system
12 Inkjet print head
14 Replaceable ink supply container
16 Fluid conduit
18 Ink ejector
22 Fluid inlet
28 Fluid outlet
29 Air accumulation part
38 interior filling space

Claims (6)

An ink jet printing system of the type having a replaceable ink supply container for supplying ink to a printhead,
A semi-permanent inkjet printhead having a fluid input for receiving ink and a discharge portion for selectively ejecting ink in response to a control signal and capable of printing ink stored in a plurality of ink supply containers ; ,
The ink storage, and a possible ink supply container replacement configured to supply the ink to the inkjet printhead,
The semi-permanent inkjet printhead includes an air accumulator 29 having a storage capacity corresponding to the total amount of air that may be generated from an air source during printing over the life of a plurality of ink supply containers, The air accumulated in the ink jet print head is received by the air accumulating unit, so that the print head prints ink stored in a plurality of ink supply containers without purging air from the ink jet print head. Louis inkjet printing system to maintain the printhead pressure range within an operating range which allows. The print head is
An internal filling space for storing ink ejected at the discharge portion;
An adjustment valve that receives ink from the fluid input section and supplies ink to the full space, and opens and closes in response to a pressure change in the full space to maintain a specified negative pressure in the full space;
The inkjet printing system of claim 1, further comprising: The print head includes an internal filling space for storing ink ejected at the discharge portion;
The air accumulating unit includes a flexible member having a first surface in contact with the outside atmosphere and a second surface in contact with the ink in the internal filling space, and the flexible member contracts in response to expansion of bubbles. The inkjet printing system of claim 1, wherein a negative internal pressure in the filled space is maintained. A fluid conduit connecting the print head and the ink supply container;
The fluid conduit has a self-sealing conduit outlet configured to connect to the print head, and a self-sealing conduit inlet, the conduit outlet being self when the conduit outlet is removed from the print head. Sealed to prevent air from entering the outlet of the conduit, the fluid conduit having an oxygen permeation characteristic of less than 100 cc · mil / ( 100 in ² · day · atm) at a temperature of 23 ° C. and a relative humidity of 0%. The inkjet printing system of claim 1, comprising a portion formed of a high air barrier material. 5. The high air barrier material of claim 4, wherein the high air barrier material is a polymer selected from the group consisting of polyacrylic ester vinylidene chloride copolymer, ethylene chloro trifluoro ethylene and polychloro trifluoro ethylene. Inkjet printing system. The fluid conduit further comprises a needle having an outlet hole and surrounded by a sliding ring ;
The ink supply container further comprises the fluid outlet configured to engage the needle and the sliding ring to move the sliding ring from a sealed position ;
The inkjet printing system of claim 4, wherein the sliding ring seals the outlet hole fluidly connected to the fluid outlet in an unsealed position.

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