WO1999008876A1 - Printing system with air accumulation control means enabling a semipermanent printhead without air purge - Google Patents
Printing system with air accumulation control means enabling a semipermanent printhead without air purge Download PDFInfo
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- WO1999008876A1 WO1999008876A1 PCT/US1998/016964 US9816964W WO9908876A1 WO 1999008876 A1 WO1999008876 A1 WO 1999008876A1 US 9816964 W US9816964 W US 9816964W WO 9908876 A1 WO9908876 A1 WO 9908876A1
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- WIPO (PCT)
- Prior art keywords
- ink
- printhead
- plenum
- fluid
- air
- Prior art date
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/17—Ink jet characterised by ink handling
- B41J2/175—Ink supply systems ; Circuit parts therefor
- B41J2/17503—Ink cartridges
- B41J2/17556—Means for regulating the pressure in the cartridge
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/17—Ink jet characterised by ink handling
- B41J2/175—Ink supply systems ; Circuit parts therefor
- B41J2/17503—Ink cartridges
- B41J2/17506—Refilling of the cartridge
- B41J2/17509—Whilst mounted in the printer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/17—Ink jet characterised by ink handling
- B41J2/175—Ink supply systems ; Circuit parts therefor
- B41J2/17503—Ink cartridges
- B41J2/1752—Mounting within the printer
- B41J2/17523—Ink connection
Definitions
- This invention relates to inkjet printers and the like and, more particularly, to an inkjet printing system that makes use of a semipermanent printhead that does not require an air purge mechanism.
- Inkjet printing systems frequently make use of an inkjet printhead mounted to a carriage which is moved back and forth across a print media, such as paper. As the printhead is moved across the print media, control electronics activate an ejector portion of the printhead to eject, or jet, ink droplets from ejector nozzles and onto the print media to form images and characters.
- An ink supply provides ink replenishment for the printhead ejector portion .
- Some printing systems make use of an ink supply that is replaceable separately from the printhead. When the ink supply is exhausted the ink supply is removed and replaced with a new ink supply. The printhead is then replaced at or near the end of printhead life and not when the ink supply is exhausted.
- a replaceable printhead is capable of utilizing a plurality of ink supplies, we will refer to this as a "semipermanent" printhead. This is in contrast to a disposable printhead, that is replaced with each container of ink.
- a significant issue with semipermanent printheads is premature failure due to loss of proper pressure regulation. To understand this failure, we need to consider printhead operation. To operate properly, many printheads have an operating pressure range that must be maintained in a narrow range of slightly negative gauge pressure, typically between -1 and -6 inches of water. Gauge pressure refers to a measured pressure relative to atmospheric pressure. Pressures referred to herein will all be gauge pressures. If the pressure becomes positive, printing and printing system storage will be adversely affected. During a printing operation, positive pressure can cause drooling and halt ejection of droplets. During storage, positive pressure can cause the printhead to drool.
- Ink that drools during storage can accumulate and coagulate on printheads and printer parts .
- This coagulated ink can permanently impair droplet ejection of the printhead and result in a need for costly printer repair.
- the printhead makes use of an internal mechanism to maintain negative pressure.
- Air present in a printhead can interfere with the maintenance of negative pressure.
- air bubbles are often left behind.
- air accumulates during printhead life from a number of sources, including diffusion from outside atmosphere into the printhead and dissolved air coming out of the ink referred to as outgassing.
- outgassing dissolved air coming out of the ink .
- the internal mechanism within the printhead can compensate for these environmental changes over a limited range of environmental excursions. Outside of this range, the pressure in the printhead will become positive.
- the present invention concerns an inkjet printing system including a semipermanent printhead having a fluid input for receiving ink and an ejection portion for depositing ink in response to control signals.
- the printing system also includes a replaceable ink supply configured for providing ink to the printhead that stores an ink volume.
- the printhead is capable of lasting throughout the life of a plurality of the ink volumes.
- the printing system includes a fluid accumulator portion in fluid communication with the printhead and the replaceable ink supply. The fluid accumulator is adapted to accommodate the air introduced into the printhead during the usage of the ink supplies without purging air from the printhead.
- a preferred embodiment of the invention concerns an ink delivery apparatus that fluidically couples to the fluid input and provides ink to the printhead.
- This ink delivery apparatus is adapted to control air introduction to the printhead such that the accumulator portion can accommodate all air introduced during the life the printhead.
- Fig. 1 depicts a schematic representation of a printing system of the present invention and includes an indication of the sources of air affecting the printing system.
- Fig. 2 is a representation, shown in perspective of a preferred embodiment of a printer that utilizes the present invention .
- Fig. 3 is a schematic representation of a preferred embodiment of a printhead of the present invention.
- Fig. 4 illustrates an isometric view of a preferred embodiment of the printhead of the present invention.
- Figs. 5A-5C are cross sectional schematic representations taken through section 5A-5A from Fig. 4.
- Fig. 6 illustrates an isometric view of a printhead poised for insertion into a carriage portion of a printing system of the present invention.
- Fig. 7A illustrates an isometric view of the printhead poised for connection to the conduit outlet of the present invention.
- Fig. 7B is a cross sectional representation of the conduit outlet taken through section 7B-7B of Fig 7A.
- Fig. 7C is a cross sectional representation of the fluidic connection between the printhead and the conduit outlet of the present invention taken through section 7B-7B of Fig. 7A.
- Fig. 8 is an ink supply receiving station of the type used in the printing system of Fig. 2, shown broken away, with an ink supply positioned for insertion into the ink supply receiving station.
- Fig. 9A is a cross sectional representation of the fluid outlet and the conduit inlet taken through section line 9A-9A of Fig. 8 prior to a fluidic connection between the fluid outlet and the fluid inlet.
- Fig. 9B is a cross sectional representation of the fluidic connection between fluid outlet and the conduit inlet taken through line 9A-9A of Fig. 8.
- Fig. 10 illustrates an isometric exploded view of the parts of a preferred embodiment of ink container 10 prior to assembly of ink container 10.
- Fig. 11 illustrates an isometric view of a preferred embodiment of ink container 10.
- Fig. 12 is a plot of the solubility of air in water versus temperature.
- Fig. 13 is an isometric view of an alternative embodiment of the ink container and the printhead of the present invention with the ink container positioned for fluidic connection to the ink container.
- Fig. 1 is a schematic representation which depicts an inkjet printing system 10 of the present invention.
- Printing system 10 includes a printhead 12 that is fluidically coupled to a replaceable ink supply or container 14 via a fluid conduit 16.
- Printhead 12 receives ink from fluid conduit 16 to allow ejector portion 18 to selectively deposit inks onto media (not shown) under control of printing system control electronics 20.
- Printhead 12 includes a fluid inlet 22 that is fluidically connected to a conduit outlet 24 associated with fluid conduit 16.
- the fluid conduit 16 receives ink from replaceable ink supply 14.
- Fluid conduit 16 includes a conduit inlet 26 that is fluidically coupled to a fluid outlet 28 associated with replaceable ink supply 14.
- ink flows from ink supply 14, through conduit 16, and to printhead 12 so that ink droplets can be ejected by nozzles (not shown) associated with ejector 18. Because printhead 12 is semipermanent, it is capable of printing a large volume of ink. Thus, ink supply 14 is periodically replaced. In an exemplary embodiment, printhead 12 is expected to last while 450 cc (cubic centimeters) of ink is printed. In this embodiment, each ink supply 14 provides 30 cc of ink to printhead 12, such that printhead 12 is expected to last during the use of 15 ink supplies.
- An aspect of the invention concerns the techniques used to limit air accumulation and to accommodate air that accumulates in printing system 10. As indicated by Fig. 1 and below, printing system 10 has a number of sources of air that ultimately accumulate in printhead 12.
- Another aspect of this invention is an accumulator mechanism that allows printhead 12 to accommodate air introduced into printing system 10 by the sources above.
- printhead 12 To prevent drooling from printhead 12, it is critical that printhead 12 maintain an internal negative pressure.
- the printhead includes an accumulator 29 that compensates for this expansion to maintain the negative pressure.
- the accumulator 29 has an upper limit volume for which it can compensate. This is referred to as the "warehouse capacity" for air.
- the "warehouse capacity" of the accumulator 29 is determined by the accumulator design and an environmental operating range.
- This environmental range is defined by an upper limit of temperature and/or a lower limit of pressure at which the accumulator 29 must accommodate a maximum amount of bubble expansion.
- this upper limit is a temperature of 140 F (degrees Fahrenheit) at a constant pressure.
- the accumulator must accommodate expansion of a volume of air equal to the warehouse capacity up to a temperature of 140 F.
- the warehouse capacity is 4.5 cc
- this exemplary accumulator must compensate for the expansion of a 4.5 cc bubble from ambient (approximately 70 F) to 140 F while maintaining a negative pressure in the plenum.
- Another aspect of this invention concerns an "air budget" that is selected to insure that the sources of air do not exceed the warehouse capacity. Within the air budget, we select how much air we will allocate for each source of air.
- An exemplary air budget is tabulated in Table 1 below:
- the sum of all budget items equals the warehouse capacity of 4.5 cc. Any single budget item can increase provided other item(s) are correspondingly decreased to assure that the air budget total does not exceed the air warehouse capacity.
- Another aspect of the invention concerns techniques used to insure that each source of air is maintained at a low enough level to keep the total air accumulated below the warehouse level.
- the techniques to accommodate air and limit air introduction will be discussed below with respect to Figs. 2-13.
- Fig. 2 depicts a representation of one preferred embodiment of printing system 10.
- the printing system 10 includes media input 30A and output 30B trays for storing media (not shown) both before and after, respectively, the media is fed through a print zone 32.
- a carriage 34 supports a plurality of printheads 12 and scans over print zone 32 to allow a plurality of ejectors 18 associated with printheads 12 to selectively deposit ink on the media.
- Each printhead 12 receives ink from one of a plurality of corresponding ink supplies 14 via conduits 16.
- Printheads 12 are semipermanent, since they can each utilize a plurality of ink containers 14. This allows printing system 10 to be of compact size.
- Ink supplies 14 of this preferred embodiment utilize different colorant inks, including black 14b, cyan 14c, magenta 14m, and yellow 14y.
- the black ink container 14b has a capacity of approximately 75 cc, and the color ink containers 14c, 14m, and 14y each have capacities of approximately 30 cc .
- the sizes of the ink containers are chosen small enough to avoid impacting the size of printing system 10 and to take shelf life considerations into account. They are selected large enough to allow for an acceptably low replacement rate . Since each printhead 12 can last throughout the usage of approximately 450 cc of ink, each printhead must utilize a plurality of ink containers 14, and hence, must be semipermanent.
- Fig. 3 illustrates a schematic representation of printhead 12 connected to fluid conduit 16.
- Printhead 12 receives ink from fluid conduit 16 at an incoming pressure and then delivers the ink to ejector 18 at a controlled internal pressure that is lower than the incoming pressure.
- Ejector 18 is fluidically coupled to a plenum 38 that stores a quantity of ink at the controlled internal pressure. Ink passes through filter element 39 before reaching ejector 18 to remove particulates .
- the negative pressure in plenum 38 is controlled using a regulator that includes actuator 40 and valve 42. As the ejector 18 deposits ink on media, the ink in plenum 38 is depleted.
- actuator 40 responds by opening valve 42, allowing ink to pass from fluid conduit 16 to plenum 38. This introduction of ink raises the pressure of plenum 38.
- actuator 40 responds by closing valve 42.
- the pressure in plenum 38 is regulated between the low pressure and the high pressure thresholds.
- Fig. 4 illustrates an isometric view of a preferred embodiment of printhead 12.
- Printhead 12 includes fluid inlet 22 for receiving ink from conduit 16 and ejector portion 18 for selectively depositing ink on media (not shown) .
- Printhead 12 also includes an internal regulator that is discussed with respect to Figs. 3 and 5A-C.
- the internal regulator includes an air conduit 43 that will be discussed with respect to Figs. 5A-C.
- Figs. 5A-5C are cross sectional schematic representations of printhead 12 taken through section 5A-5A from Fig. 4.
- the internal structure of printhead 12 is simplified to more clearly illustrate functional aspects of the pressure regulation system in printhead 12.
- similar element numbering is used to identify similar elements.
- Printhead 12 includes an outer housing 44 that supports ejector portion 18. In fluid communication with ejector portion 18 is plenum 38. Inside plenum 38 is the actuator 40 and valve 42 for selectively allowing ink into plenum 38.
- Valve 42 includes a nozzle 46 that is fluidically connected to fluid inlet 22 for allowing ink to enter plenum 38 and a valve seat 48 for sealing nozzle 46.
- Valve seat 48 is formed of a resilient material to assure reliable sealing of valve 42.
- Valve seat 48 is fixedly mounted to a pressure regulator lever 50 that rotates about a regulator axle 50A. Rotation of lever 50 opens and closes valve 42 based upon changes in pressure in plenum 38, as illustrated in Figs. 5A-C.
- Printhead 12 also includes an accumulator lever 52 that rotates about an accumulator axle 52A.
- a spring 54 connects the regulator valve lever 50 to the accumulator lever 52, and biases the levers toward each other. The spring is connected relatively closer to accumulator axle 52A than to regulator axle 50A.
- An expandable bag 56 is located between the accumulator lever 52 and the regulator lever 50.
- a first surface of the expandable bag 56 communicates with outside atmosphere via air conduit 43, and a second surface of the bag 56 is in contact with ink in plenum 38.
- the bag 56 expands and contracts in response to pressure differences between the plenum 38 and outside atmosphere.
- the bag 56, the regulator lever 50, and the spring 54 function as the actuator 40 as was discussed with respect to Fig. 3.
- Fig. 5A illustrates an initial state of printhead 12 when bag 56 is fully collapsed.
- bag 56 expands to compensate for the volume of ink ejected by ejector 18.
- the bag volume increases until it begins pressing on accumulator lever 52 on one side, and regulator lever 50 on the other side, opposing the force exerted by spring 54.
- the levers begin to pivot outwardly in opposition.
- the accumulator lever 52 moves first, since the moment exerted by spring 54 on accumulator lever 52 is less than the moment exerted by spring 54 on regulator lever 50. The accumulator lever moves until it contacts outer housing 44, as indicated by Fig. 5B.
- the range of motion of accumulator lever 52 allows for up to a warehouse capacity of 4.5 cc of accumulated air in plenum 38 while maintaining a negative pressure in plenum 38 over the specified environmental operating range. If the accumulated air exceeds 4.5 cc, then printhead 12 may drool, causing printhead and printer damage and affecting operation of ejector 18. Thus, the cumulative volume of all sources of air should be kept below 4.5 cc, the warehouse volume.
- valve 42 could be an electromechanical valve, such as a solenoid valve.
- the actuator 40 could be a pressure transducer that provides signals to a circuit for opening and closing valve 42.
- the outer walls of plenum 38 should be at least partly compliant.
- One way to do this is to provide a rubber diaphragm 60 that separates plenum 38 from an outside atmosphere that can move in response to bubble expansion; thus diaphragm 60 is functioning as the accumulator 29.
- plenum 38 can be surrounded by a spring loaded bag that similarly functions as an accumulator 29.
- Each alternative accumulator design will have its own air accumulation limits and hence warehouse capacity. To avoid the deleterious effects of positive pressure, the sum of the sources of air must be kept below this warehouse capacity.
- the sources of air and techniques used to maintain them within their respective budgets will now be discussed with respect to Figs 6-13. Budgeting and controlling each source to meet overall budget goals are important aspects of this invention .
- the first source of air is the initial air present in printhead 12 before it is installed into printing system 10.
- 0.3 cc of air is budgeted for this source, which includes air introduced by manufacturing processes, air that diffuses into printhead 12 between manufacturing and installation of printhead 12 into printing system 10, and air that is drawn into printhead 12 through the fluid inlet 22 or the ejector portion 18.
- a number of design and assembly methods are utilized for fabricating printhead 12 as will be discussed below.
- printhead 12 When printhead 12 is manufactured, air is introduced as printhead 12 is filled with ink. To minimize such air, the following ink fill process is used: (1) Printhead 12 is initially flushed with C02 gas by providing a source of C02 gas at the fluid inlet 22 and by providing a vacuum source at the ejector 18 of printhead 12 until nearly all of the gas resident in printhead 12 is composed of C02. (2) Next, printhead 12 is filled with degassed ink (ink having less than the saturation level of dissolved oxygen) by providing a source of degassed ink at the fluid inlet 22 and a source of vacuum at ejector 18 until printhead 12 is filled with ink. Any bubbles left behind during the fill process will be primarily composed of C02 and will quickly dissolve in the ink. Further, any impurities in the bubbles (such as air) will be absorbed by the ink, since it is degassed.
- degassed ink ink having less than the saturation level of dissolved oxygen
- Printhead 12 is also fabricated with high air diffusion barrier materials to minimize diffusion of air into printhead 12 between the ink fill process and installation of printhead 12 into the printer.
- the outer housing 44 of printhead 12 is fabricated from LCP (liquid crystal polymer) .
- Other high barrier materials will also work effectively, such as PET (polyethylene terephthalate) or metallized plastic.
- the bag 56 is preferably formed from a multilayer plastic film, with at least one layer having a high air diffusion barrier property.
- a preferred high barrier material is PVDC (polyvinylidene chloride) .
- Other layers are utilized to maximize adhesion and flexibility, such as LDPE (low density polyethylene) .
- a second source of air is introduced when a "printhead connection" is established between conduit outlet 24 and fluid inlet 22.
- Fig. 6 illustrates the initial installation of printhead 12 into carriage 34. Printhead 12 is installed into carriage 34 by inserting it in a substantially downward motion. Upon insertion, conduit outlet 24 connects to fluid inlet 22 associated with the printhead 12.
- Figs. 7A-C Details of the fluid connection between fluid inlet 22 and conduit outlet 24 are further illustrated with respect to Figs. 7A-C.
- Fig. 7A illustrates the printhead 12 poised for fluidic connection to the conduit outlet 24.
- Fig. 7B illustrates the conduit outlet 24 prior to the fluidic connection.
- Fig. 7C illustrates the completed fluidic connection between fluid inlet 22 and conduit outlet 24.
- the fluid inlet 22, associated with the printhead 12, includes a downwardly extending hollow needle 62 having a closed, blunt lower end, a blind bore (not shown) and a lateral hole 66.
- the blind bore is fluidically connected to the nozzle 46 previously illustrated in Figs. 5A-C and to the lateral hole 66.
- the needle 62 is surrounded by a shroud 68.
- the conduit outlet 24 includes a hollow cylindrical housing 70 that extends upward.
- the hollow housing 70 has an inlet 72 in fluid communication with conduit 16.
- the hollow housing 70 has an upper end supporting a pre-slit septum 74 that is secured to housing 70 by a crimp cap 76.
- a sealing member 78 is urged against the septum 74 by a spring 80.
- the shroud 68 helps to align the septum 74 to the needle 62.
- the upper end of the conduit inlet 24 is sized to properly engage fluid inlet 22.
- the diameter of the upper end of conduit inlet 24 should be small enough to be received by shroud 68, but large enough to control alignment variation between fluid inlet 22 and conduit outlet 24 to assure a reliable fluidic connection between needle 62 and septum 74.
- needle 62 passes through the septum 74 to displace the sealing member 78 down into the cylindrical housing 70.
- ink can flow from conduit 16, into housing inlet 72, around the sealing member 78, into lateral hole 66, into the blind bore, and into nozzle 46 (Figs 7A-C) .
- conduit outlet 24 and fluid inlet 22 introduce a minimal amount of air to printhead 12. If printhead 12 is disconnected from conduit 16, there may be a negative pressure present in conduit 16 that would tend to draw air into conduit outlet 24. To prevent this, septum 74 immediately self-seals after needle 62 is withdrawn, preventing air from entering conduit 16. After extended usage, however, septum 74 may take on a compression set such that it does not immediately self seal when disconnected from the needle 62. To assure an immediate and reliable seal, sealing member 78 provides a redundant seal of conduit outlet 24. The air budget of TABLE 1 allocates 0.1 cc of air for this fluidic disconnection and reconnection, but the actual air introduced is insignificant for printhead 12 because of the reliable self-sealing nature of conduit outlet 24.
- a third source of air is air present in conduit 16 when the printhead 12 is initially installed, referred to as
- tubing startup air In an exemplary embodiment, this provides no more than 1.3 cc of air to printhead 12.
- fluid conduit 16 may be initially unprimed (empty) to address reliability issues. For example, during shipment from manufacturing site to customer, printing system 10 can experience temperature fluctuations that may cause freezing and expansion of any ink in fluid conduit 16 which could cause damage to fluid conduit 16. For this reason, fluid conduit 16 is initially shipped dry from the factory.
- a fourth source of air is diffusion of air from outside into conduit 16 and into printhead 12 while printhead 12 is installed in printing system 10.
- the total diffusion is kept to 1.0 cc or less by the use of high air diffusion barrier materials for fabricating the printhead and the conduit.
- the printhead is fabricated of high diffusion barrier polymers .
- the fluid conduit includes tubing fabricated of a low air diffusion material, with an oxygen permeability characteristic of less than 100 cc»mil/(100 in 2 «day»atm) at 23°C (degrees Celsius) 0% Rh (relative humidity) .
- flexible polymers suitable for this tubing include PVDC (polyvinylidene chloride copolymer) , ECTFE (ethylenechlorotrifluoroethylene) , and PCTFE
- FIG. 8 illustrates ink supply 14 poised for substantially downward insertion into receiving station 36, leaving out details that do not pertain to the invention.
- Ink supply 14 includes a fluid reservoir 82 that is in fluid communication with fluid outlet 28.
- fluid outlet 28 couples with conduit inlet 26 to allow ink to flow from fluid reservoir 82 to conduit 16 and to printhead 12 (Fig. 1) .
- Figs. 9A and 9B are cut-away cross sectional representations taken through line 9A-9A of Fig. 8 that include only the fluidic connection.
- Fig 9A illustrates fluid outlet 28 and conduit inlet 26 prior to fluidic connection.
- Fluid outlet 28 associated with ink supply 14 includes a hollow cylindrical boss 84 that extends downward from an ink supply chassis 86.
- the hollow boss 84 has an upper end in fluid communication with reservoir 82 and a lower end supporting pre-slit septum 88 that is secured to boss 84 by crimp cap 90.
- a sealing member 92 is urged against septum 88 by spring 94.
- Conduit inlet 26 includes an upwardly extending hollow needle 96 having a closed, blunt upper end, a blind bore (not shown) and a lateral hole 98.
- the blind bore is fluidically connected to the lateral hole 98.
- the end of the needle 96 opposite the lateral hole 98 is fluidically connected to conduit 16 for providing ink to printhead 12.
- a sliding collar 100 surrounds the needle 96 and includes a compliant portion 102.
- the sliding collar 100 is biased upwardly by spring 104 to maintain a position whereby complaint portion 102 seals lateral hole 98 from an outside atmosphere .
- Conduit outlet 26 also includes an upwardly extending boss 105 that surrounds sliding collar 100. Upwardly extending boss 105 provides protection for needle 96, retention for sliding collar 100, and an alignment function for fluid outlet 28.
- Fig 9B illustrates the fluidic connection between fluid outlet 28 and conduit inlet 26.
- the lower or distal end of the fluid outlet 28 first engages a tapered portion 105a and an inner surface 105b of boss 105 and is guided into alignment with needle 96.
- the lower end of fluid outlet 28 then pushes the sliding collar 100 downward.
- the needle 96 enters the septum 88 and passes through the septum 88 to displace the sealing member 92 up into the cylindrical boss 84.
- ink can flow from the ink supply reservoir 82, through the boss 84, around the sealing member 92, into the lateral hole 98, to the fluid conduit 16 and to printhead 12.
- Fluid outlet 28 is sized to reliably engage fluid inlet 26 to avoid introduction of air to conduit 16. Fluid outlet 28 should be of sufficient length to properly engage sliding collar 100 and to push sliding collar 100 sufficiently far from lip 105c to assure connection between lateral hole 98 and the inside of hollow boss 84. The lower end of fluid outlet 28 should have a sufficiently small diameter to be received in boss 105, but large enough to control alignment variation between needle 96 and septum 88 when engaging the tapered portion 105a and the inner surface 105b of boss 105.
- conduit inlet 26 Because a plurality of ink supplies are connected and disconnected to conduit inlet 26, it is very important that fluidic disconnection and reconnection between conduit inlet 26 and fluid outlet 28 introduce a minimal amount of air to conduit 16.
- ink supply 14 When ink supply 14 is disconnected from conduit 16, there may be a slight negative pressure present in conduit 16 that would tend to draw air into conduit inlet 26. To prevent this, sliding collar immediately seals lateral hole 98 when ink supply 14 is disconnected.
- septum 88 and sealing member 92 On the fluid outlet side, septum 88 and sealing member 92 immediately self-seal, preventing air from being drawn into ink supply 14. This is important if ink container 14 is removed and reinstalled to prevent air introduction.
- the air budget of TABLE 1 only allocates 0.1 cc of air of air for ink supply 14 connection over the life of printhead 12.
- a sixth source of air is "ink supply (container) free air", or bubbles in the ink supply 14 that are drawn from the ink supply 14, through conduit 16, and into printhead 12. This free air is initially present in reservoir 82 and/or fluid outlet 28.
- ink supply 14 is installed in a substantially vertical orientation as depicted in Fig. 8. Any free air will tend to buoyantly rise to an upper portion of ink supply 14. Because of this arrangement, the "ink supply free air" contribution to the air budget is 0.1 cc.
- ink supply 14 if sufficient free air is present in ink supply 14, it may still be delivered to conduit 16 when ink supply 14 is nearly depleted of ink. Thus, it is desirable to limit the total volume of air bubbles that can accumulate in ink container 1 .
- Figs. 10 and 11 show a exploded and fully assembled views of a preferred embodiment of ink supply 14, leaving out details that do not pertain to the invention. Referring to Fig. 10, assembly of ink supply 14 includes the following steps:
- chassis 86 that includes outwardly extending fluid outlet boss 84 and perimetrical sealing surfaces 106.
- Film sheets are of a high air diffusion barrier multilayer construction.
- the layers include nylon, metallized (silver) PET, and LDPE.
- the process described above minimizes initial and accumulated free air in two major respects.
- a seventh source of air accumulation in printhead 12 is outgassing.
- the mechanism for this outgassing is a solubility change that occurs as ink passes through plenum 38 of printhead 12.
- the solubility of dissolved air in the ink decreases, causing diffusion of air from the ink into bubbles present in plenum 38.
- This solubility decrease is primarily temperature-induced, as will be explained now.
- Fig. 12 illustrates a solubility curve for water that plots air solubility in water versus water temperature. As can be seen from the curve, the solubility of water decreases as the temperature is raised.
- the thermal ink jet inks associated with this invention are at least partly water based. Hence, many will tend to have air solubility curves having a similar shape to that illustrated in Fig. 12.
- ejector portion 18 warms the ink in plenum 38. This causes ink near ejector portion 18 to be supersaturated with air, causing diffusion of air from the ink into bubbles in plenum 38. As a result, the bubbles grow in size.
- One way to reduce the amount of outgassing is to include certain anti-outgassing additives that have the effect of reducing the slope of the solubility curve, thus reducing the outgas rate.
- a preferred additive that has this effect is ethoxylated glycerol.
- additional anti-outgassing additives suitable for use in the present invention include 2-pyrrolidone, N-methyl pyrrolidone, ethylene glycol, 2-propanol, 1-propanol, cyclohexanol, EHPD. The list below indicates even more additives:
- Ketones or ketoalcohols such as acetone, methyl ethyl ketone, and diacetone ether.
- Ethers such as dioxane.
- Esters such as ethyl acetate, ethyl lactate, ethylene carbonate, and propylene carbonate.
- Diols such as 1,4 butanediol, 1,2 pentanediol, 1,5 pentanediol, and 1,2 hexanediol .
- Polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, neopentylglycol, polyethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, glycerol, and thiodiglycol .
- Lower alkyl mono- or di-ethers derived from alkylene glycols such as diethylene glycol mono-methyl (or ethyl) ether, and tetraethylene glycol mono-methyl (or - ethyl) ether.
- the anti-outgassing additive which may be one of the above constituents or a mixture thereof, is present in the range of at least 2% by weight and preferably
- An exemplary ink having controlled outgas properties is as follows:
- Anti-outgassing additive 12 ethoxylated glycerol, etc.
- Ink Vehicle 80 (water plus additional solvents)
- Additional Ingredients in 2 combination e.g. biocides, surfactants, Bleed control agents, buffers, etc.
- the exemplary black ink indicated above has the average slope of the tangent to the solubility curve reduced to approximately "h> or less than that of water, between approximately 25°C and 60°C.
- the change in solubility of air in the ink between 25°C and 60°C is reduced to approximately half of the change expected for water by adding the additive.
- the exemplary black ink that has such an additive has a reduced outgas rate that is less than 4 of that of water. This results in a budget contribution of 1.6 cc of air.
- ink pressurization An aspect of ink supply 14 that will increase the rate of outgassing is ink pressurization .
- Pressurization is typically done for printing systems requiring high flow rate printing to eliminate the effect of pressure drops between reservoir 82 and printhead 12.
- a preferred embodiment of ink supply 14 includes a pressurization means 116 associated with ink supply 14.
- Pressurization means 116 can be a pump that is integral with ink supply 14.
- pressurization means 116 could be an air inlet that is in fluid communication with a region surrounding reservoir 82.
- a source of pressurized gas would then be connected to pressurization means 116 to pressurize the ink contained in fluid reservoir 82. In either case, the pressurization means provides pressurized ink at fluid outlet 28.
- pressurization means 116 will raise the solubility of gas in the ink contained in ink supply 14 via Henry's Law. If constant pressure is applied, the ink will become more saturated with air over time, increasing the outgas rate of the ink as it travels through printhead 12.
- pressurization means 116 to be an intermittent pressure source that only pressurizes the ink delivered to conduit 16 when necessary for printing and usually relieves pressure at fluid outlet 28 when printing system 10 is idle. Since most of the time is spent not printing, this minimizes the portion of outgassing contributed by pressurization.
- FIG. 11 illustrates an alternative ink supply 14' that is pluggably mountable directly to printhead 12' in an "on carriage" configuration.
- Ink supply 14' includes fluid outlet 28' that directly connects to fluid inlet 22' associated with the printhead 12', eliminating the need for fluid conduit 16 therebetween. This would eliminate some major sources of air, including conduit or tubing startup, conduit or tubing diffusion, and one of the fluidic connections. This would have the effect of increasing printhead lifetime or decreasing the required air warehouse capacity.
- Another alternative is to provide the pressure regulation and/or accumulator capacity in the ink supply 14' rather than the printhead 12' . This would tend to simplify the overall fluid delivery system, at the expense of accurate pressure control in printhead 12' .
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000509592A JP3909802B2 (en) | 1997-08-18 | 1998-08-14 | Printing system with air accumulation control means enabling the use of a semi-permanent print head without air purging |
DE69804629T DE69804629T2 (en) | 1997-08-18 | 1998-08-14 | PRINT SYSTEM WITH AIR STORAGE CONTROL FOR SEMI-PERMANENT PRINT HEAD WITHOUT VENTILATION |
EP98940913A EP1003640B1 (en) | 1997-08-18 | 1998-08-14 | Printing system with air accumulation control means enabling a semipermanent printhead without air purge |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US91483297A | 1997-08-18 | 1997-08-18 | |
US08/914,832 | 1997-08-18 | ||
US09/037,550 US6203146B1 (en) | 1998-03-09 | 1998-03-09 | Printing system with air accumulation control means enabling a semipermanent printhead without air purge |
US09/037,550 | 1998-03-09 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999008876A1 true WO1999008876A1 (en) | 1999-02-25 |
Family
ID=26714240
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/016964 WO1999008876A1 (en) | 1997-08-18 | 1998-08-14 | Printing system with air accumulation control means enabling a semipermanent printhead without air purge |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP1003640B1 (en) |
JP (1) | JP3909802B2 (en) |
KR (1) | KR100532297B1 (en) |
CN (1) | CN1099346C (en) |
DE (1) | DE69804629T2 (en) |
WO (1) | WO1999008876A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002086702A (en) * | 2000-09-12 | 2002-03-26 | Canon Inc | Recording mechanism, ink jet recording apparatus and imager with recording apparatus |
EP1223039A1 (en) * | 2001-01-11 | 2002-07-17 | Hewlett-Packard Company | Printhead air management using unsaturated ink |
US6863387B2 (en) | 1998-03-09 | 2005-03-08 | Hewlett-Packard Development Company, L.P. | Ink supply with air diffusion barrier for unsaturated ink |
US7784923B2 (en) | 1999-10-08 | 2010-08-31 | Seiko Epson Corporation | Ink cartridge, and ink-jet recording apparatus using the same |
US8083340B2 (en) | 2006-03-20 | 2011-12-27 | Seiko Epson Corporation | Container and method for storing light-curable ink |
Families Citing this family (13)
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FR2816241B1 (en) * | 2000-11-07 | 2003-03-28 | Segepar | NON-RETURN SYSTEM FOR INK SUPPLY CIRCUIT AND INK CARTRIDGE |
ATE454986T1 (en) | 2001-11-12 | 2010-01-15 | Seiko Epson Corp | FLUID INJECTION DEVICE |
JP2006326855A (en) * | 2005-05-23 | 2006-12-07 | Canon Finetech Inc | Inkjet system image forming apparatus |
JP4560401B2 (en) | 2004-12-22 | 2010-10-13 | キヤノン株式会社 | Ink tank and ink jet recording apparatus |
JP5316326B2 (en) * | 2009-09-04 | 2013-10-16 | 株式会社リコー | Liquid container, method for assembling liquid container, method for disassembling liquid container, and image forming apparatus |
JP5471461B2 (en) * | 2010-01-08 | 2014-04-16 | セイコーエプソン株式会社 | Liquid container and liquid ejecting apparatus |
US9931859B2 (en) * | 2014-01-31 | 2018-04-03 | Hewlett-Packard Development Company, L.P. | Removing air from a printing fluid channel |
US9770927B2 (en) * | 2014-06-26 | 2017-09-26 | Hewlett-Packard Development Company, L.P. | Container assembly |
WO2017108094A1 (en) * | 2015-12-22 | 2017-06-29 | Hewlett-Packard Development Company, L.P. | Printing fluid cartridge for a pumped printing fluid system |
US10899136B2 (en) | 2017-01-24 | 2021-01-26 | Hewlett-Packard Development Company, L.P. | Printing fluid recirculation |
EP3787903B1 (en) | 2018-05-03 | 2024-02-21 | Hewlett-Packard Development Company, L.P. | Air purging |
US10814634B1 (en) * | 2019-07-11 | 2020-10-27 | Xerox Corporation | Printhead cap for attenuating the drying of ink from a printhead during periods of printer inactivity |
CN115164526B (en) * | 2022-06-28 | 2023-11-14 | 中核核电运行管理有限公司 | Radioactive sludge drying system |
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Cited By (10)
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US6547377B2 (en) | 1998-03-09 | 2003-04-15 | Hewlett-Packard Company | Printhead air management using unsaturated ink |
US6863387B2 (en) | 1998-03-09 | 2005-03-08 | Hewlett-Packard Development Company, L.P. | Ink supply with air diffusion barrier for unsaturated ink |
US6874873B2 (en) | 1998-03-09 | 2005-04-05 | Hewlett-Packard Development Company, L.P. | Printhead air management using unsaturated ink |
US7784923B2 (en) | 1999-10-08 | 2010-08-31 | Seiko Epson Corporation | Ink cartridge, and ink-jet recording apparatus using the same |
US8636347B2 (en) | 2000-01-21 | 2014-01-28 | Seiko Epson Corporation | Ink cartridge, and ink-jet recording apparatus using the same |
US8998394B2 (en) | 2000-01-21 | 2015-04-07 | Seiko Epson Corporation | Ink cartridge, and ink-jet recording apparatus using the same |
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US8083340B2 (en) | 2006-03-20 | 2011-12-27 | Seiko Epson Corporation | Container and method for storing light-curable ink |
Also Published As
Publication number | Publication date |
---|---|
EP1003640B1 (en) | 2002-04-03 |
JP2001514985A (en) | 2001-09-18 |
JP3909802B2 (en) | 2007-04-25 |
CN1260750A (en) | 2000-07-19 |
EP1003640A1 (en) | 2000-05-31 |
CN1099346C (en) | 2003-01-22 |
DE69804629D1 (en) | 2002-05-08 |
KR20010022967A (en) | 2001-03-26 |
KR100532297B1 (en) | 2005-11-29 |
DE69804629T2 (en) | 2003-02-13 |
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