Ink supply for impulse ink jet system, said ink supply including a cap having a threaded perphery, a valve supported by said cap and a projection for extending from the cap into an ink reservoir

Abstract

An ink supply system for an impulse ink jet apparatus includes a hand held peristaltic device for priming. Ink is supplied by a removable container by gravity feed through a valve mechanism.

Description

BACKGROUND OF THE INVENTION

This invention relates to impulse ink jet devices and ink supply systems for such devices and methods of operation.

Impulse ink jet devices which provide a drop on demand in response to the state of energization of a transducer are typically supplied with ink from relatively small cartridges since the volume of ink consumed in an impulse ink jet device is relatively small as a normal rule. However, certain industrial applications of impulse ink jet devices require large volumes of ink over extended periods of time. For example, on-line printing of corrugated containers may require a plurality of ink jet print heads where each head comprises a large number of jets so as to produce relatively large characters and/or bar codes. Under these circumstances, a large volume of ink is used for extended periods of time. The use of small cartridges becomes impractical. For printing in this type of application, a relatively large ink supply is necessary, e.g., a container holding 125, 250, 500 or 1000 milliliter. The use of such a large ink supply does however pose certain problems for an impulse ink jet apparatus.

First, an impulse ink jet apparatus must be primed properly with ink in order to operate properly. Priming of an impulse ink jet requires that positive pressure be generated in connection with the supply of ink so as to force the ink through the ink jet chambers and the orifices of the ink jet while preventing the sucking of ink back through the orifices and the chambers upon completion of priming. One possibility for priming involves a bottle squeezing technique with some relief of the built-up pressure through the use of various types of valves including umbrella, duck bill and flapper valves. Such valves are required to be sensitive to back pressure while being strong enough to seal ink in during the squeezing phase. In addition, such valves may present problems of material compatibility with the inks used. Accordingly, it may be difficult to reliably design to meet the above-stated criteria. Another possibility includes a manually operated valve but this requires precisely timed manual procedures which may pose difficulties to operators in the field.

Priming of an impulse ink jet system may also be accomplished by pressurizing an air space above an ink reservoir. However, any increase in ink pressure in a container in which the ink reservoir is located will continue to force ink out through the ink jet device even after the pressure is removed. The device may therefore "weep" uncontrollably. Pressure could be applied directly to the container by puncturing a hole in the container in the air space above the ink which may also be used so as to relieve pressure within the container as soon as the pressure is removed from the container. This option, however, makes removal of partially filled containers messy as well as foreclosing on ecologically sound refilling policy.

Peristaltic pumps have been proposed for use in priming impulse ink jet apparatus wherein rollers are moved into contact with a tube containing ink, rolled along the tube containing ink and then separated from the tube so as to allow the free flow of ink through the tube. Such a mechanism is complex, expensive and may be difficult to implement in a variety of applications.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a large ink supply for an impulse ink jet device.

It is a further object of this invention to provide a priming mechanism for a large ink supply used in an impulse jet system which is reliable, easy to use and poses no material compatibility problems.

It is a further object of this invention to provide an ink supply system and an associated priming mechanism which is ecologically sound.

It is a still further object of this invention to provide an ink supply and associated priming mechanism which does not cause weeping from the head at the conclusion of priming.

It is a still further object of this invention to provide an ink supply and associated priming mechanism which substantially eliminates the possibility of any spillage of ink.

It is a still further object of this invention to provide a priming mechanism which imposes the minimum of constraints on the remainder of the system.

In accordance with these and other objects of the invention, a preferred embodiment of the invention comprises an impulse ink jet apparatus including an impulse ink jet head, a supply base comprising a reservoir for ink and adapted to receive an ink supply and means for coupling the ink jet head to the supply base.

In accordance with one important aspect of the invention, an impulse ink jet system comprises a removable ink supply container containing liquid ink. An ink reservoir is coupled to the container so as to permit the flow from the container to the reservoir. The reservoir includes a vent for allowing air to escape from the reservoir when the reservoir contains ink supplied by the supply container. A tubular means is coupled between the ink jet device and the reservoir so as to permit the flow of ink from the reservoir to the device after venting in the reservoir. Means are provided for increasing the flow of ink under pressure through the tubular means to the impulse ink jet device without increasing the pressure of ink within the reservoir.

In accordance with another important aspect of the invention, a method of operating an impulse ink jet system is provided including the steps of delivering liquid ink in a closed container to the impulse ink jet system and creating a reservoir of liquid ink from the closed container outside the closed container and said ink jet device. The reservoir of liquid ink is vented and ink flows from the reservoir after venting to the ink jet device. The flow of ink from the reservoir to the ink jet device is increased for priming the device and expelling air from the device without increasing the pressure within the reservoir. Droplets of ink are then ejected from the ink jet device on demand.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a ink jet apparatus;

FIG. 2 is a sectional view through one of the ink jet heads of FIG. 1 taken along the line 2--2;

FIG. 3 is a plan view of the hand gripped peristaltic pumping apparatus shown in FIG. 1;

FIG. 4 is an end view of the peristaltic pumping apparatus of FIG. 3;

FIG. 5 is another end view of the peristaltic pumping apparatus shown in FIG. 3;

FIGS. 6 through 8 are schematic views of the peristaltic pumping apparatus shown in FIGS. 3-5 in various positions;

FIG. 9 is a sectional view of the ink reservoir and supply of FIG. 1 taken along line 9--9;

FIG. 10 is an enlarged sectional view of the ink supply mounted on the reservoir base as shown in FIG. 1; and

FIG. 11 is an enlarged sectional view of the ink supply prior to mounting on the reservoir base.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, an ink supply system is shown comprising a reservoir 10, a peristaltic pumping apparatus 12, a manifold 14 and a plurality of impulse ink jets 16. The reservoir 10 is coupled to the manifold 14 by a flexible tube 18 which is coupled to the peristaltic pumping apparatus 12. Flexible tubes 20 couple the manifold to the various heads 16. Each of the heads 16 comprises a plurality of impulse ink jet devices 22 as shown in FIG. 2. The devices 22 are made in accordance with the disclosure of U.S. Pat. No. 4,459,601 which are incorporated herein by reference. A transducer 24 is coupled to an ink jet chamber 26 through a foot 27 having an orifice 28 for the ejection of droplets and an input opening 30 to which ink is supplied from the tubes 20 coupled to the manifold 14. Droplets are ejected on demand in response to the state of energization of the transducer 24 of the control of an electronic system. It will be appreciated that each of the heads 16 must be actually positioned above the uppermost level of ink in the reservoir 10 so as to avoid placing the ink under any sort of pressure head which would cause weeping from the orifices 28.

In accordance with one important aspect of the invention, a peristaltic pumping apparatus 12 is adapted to be gripped by hand with fingers being inserted through the elongated opening 32 and a pedestal 34 engaged by the palm or the base of the thumb. As also shown in FIGS. 3 through 5, the apparatus 12 comprises the U-shaped structure 36 carrying a squeezing surface in the form of a roller 38 including caps 39 which is snapped into place at the end of one spring arm 40 and a support surface 42 which extends from a position adjacent the roller 38 to another spring arm 43 which is integrally formed with a base 44 in which the finger opening 32 is located. As shown in FIG. 4, the base 44 includes an opening 46 through which the flexible tube 18 may extend when in contact with the support surface 42, and the base 44 also includes an opening 48 as shown in FIG. 5 including a lead-in 50 through which the tube 18 as shown in FIG. 1 may extend.

When the peristaltic pumping apparatus of FIGS. 3 through 5 is actuated by application of hand pressure as described above, the squeezing surface on the roller 38 moves through a peristaltic pumping orbit so as to force ink through the flexible tube during a peristaltic pumping stroke when the pressure of the hand is removed so as to prevent sucking ink back through the tube 18 and the ink jet print head 16 shown in FIG. 1. The peristaltic pumping orbit may best be appreciated by reference to FIGS. 6 through 8 which will now be described in detail.

As shown in FIG. 6, the roller 38 is in the static position, i.e., before application of any hand pressure, and spaced from the tube 18. As shown in FIG. 7, the roller 38 is moved along the tube 18 which is pressed against the support surface 42 and pressure is applied through the tube 18. The movement depicted in FIG. 7 is the peristaltic pumping stroke. At the conclusion of the peristaltic pumping stroke as shown in FIG. 8, the hand pressure is released and the roller 38 is automatically lifted off the tube 18 so as to permit the tube 18 to return to the decompressed position and the roller 38 is automatically moved back to the static position shown in FIG. 6. The movement of the roller 38 through the peristaltic pumping orbit is achieved by the spring arms 40 and 43. During the application of hand pressure to the apparatus 12, the spring 40 permits the roller 38 to advance along the surface 42 at an attack angle of no more than 45.degree.. As the peristaltic pumping action proceeds as a result of the continued application of pressure as shown in FIG. 7, the spring arm 43 is biased to the point that upon release of the hand pressure, the roller moves away from the tube 18 as shown in FIG. 8 and returns to the static position as shown in FIG. 6. It has been found that the peristaltic pumping apparatus 12 may be integrally formed from a variety of plastic materials to provide the appropriate characteristic including the necessary resilience for the springs 40 and 43. However, Nylon 6/6 is especially preferred.

In accordance with another important aspect of the invention, the ink reservoir 10 permits a relatively large supply of ink to be used while facilitating the priming in an efficient, ecologically sound and easy manner. More particularly, as best shown in FIG. 9, the reservoir 10 includes an ink supply base 52 including a cover 53 having a container support portion 54 and a level detect portion 56. The container support portion includes an opening 58 in the cover 53 which extends upwardly and is adapted to receive an ink supply apparatus including a closed container 60 as delivered to the base 52. Cover 53 further includes a shoulder portion 53' and a second opening 58', which as shown has a diameter that is smaller than the inner diameter of the neck and the diameter of the threaded periphery of the cap. A valve actuating means in the form of a projection 62 is located immediately below the opening 58 which is adapted to open the valve associated with the container 60 shown in FIG. 1 which will be described in more detail subsequently. The opening 58 is located in a neck 63 which extends upwardly from the cover 53 and includes threads 64 for receiving the delivered ink supply as best shown in FIGS. 9 and 10.

The level detect portion 56 in the cover 53 includes a level detect mechanism 66 which is mounted on the cover 53. As shown, the mechanism 66 includes a float 68 which is free to move along the shaft 70, to the position shown in phantom which actuates a proximity switch so as to signal the level 73 of the ink within the reservoir formed by the base 52. The signal wires 76 are coupled to the proximity switch as shown. A washer 78 holds the float 68 on the shaft 70. A level detect device of this type is sold by Signal Systems International under the tradename FS2-B Liquid Level Switch.

A port 80 in the base 52 is provided which may be coupled to the tube 18 as shown in FIG. 1. The port 80 may actually be located in a separate fitting. A vent opening 92 is also provided in the top of the cover 53 as shown or may be provided elsewhere for venting the reservoir hereby preventing an increase in pressure within the reservoir. A filter 93 is shown in base 52 adjacent the fitting 80 for filtering ink flowing to the ink jet device.

In accordance with another important aspect of the invention, a replaceable ink supply which is delivered to and mounted on the cover 53 comprises a valve mechanism which interrupts gravity feed of ink into the base 52. This will now be discussed in detail with respect to FIGS. 10 and 11. As shown, the ink supply comprises the container 60 having a neck 86 which is engaged by the threaded cap 88 terminated in a projection 89 having an opening 90 adapted to be aligned with the actuating member 62 in the base 52. A valve enclosure 92 is inserted into the neck 86 of the container 60 so as to enclose a plunger or valve member 94 in conjunction with the cap 88. As shown in FIG. 11, the plunger member 94 is biased closed by the spring 96 which encircles a shaft 98 of the plunger member 94. However, as shown in FIG. 10, the plunger member 94 is opened or unseated from the cap 88 by contact between the valve actuating member 62 and a concave actuating surface 100 of the plunger member 94. In this manner, ink from the container 60 is permitted to flow upon mounting of the container 60 on the base 52 so as to create a reservoir of ink (outside the closed container 60 and the ink jet devices 16 without any extra steps on the part of the operator and without any leakage from the container 60. It will also be appreciated that the container 60 may be readily refilled after removal from the base 52 by simply depressing plunger member 94 thereby providing an ecologically sound supply system.

It will be appreciated that the manifold 14 is optional and a single head 16 may be used with the peristaltic pumping apparatus 12. It will also be appreciated that the manifold 14 may be used with a plurality of peristaltic pumping apparatus 14, one for each tube 20.

Although a particular embodiment of the invention has been shown and described, it will be appreciated that other modifications and embodiments will occur to those of ordinary skill in art which will fall within the true spirit and scope of the appended claims.

Claims

1. An ink supply for storing ink jet ink for use in an impulse ink jet system, said ink jet system including a base having a reservoir for holding ink, a cover enclosing said reservoir, a neck extending upwardly from said cover and having a threaded inner surface for engaging the ink supply when the ink supply is inserted within a first opening within the neck, said cover having a second opening that is concentric with and below said neck and said first opening to permit ink to flow from the ink supply, through the second opening and into said reservoir, wherein a flat shoulder portion of said cover surrounds said second opening and controls said ink supply by stopping further insertion of said ink supply once said ink supply is fully mounted on said base such that the ink supply abuts said shoulder portion, wherein said ink has a top surface that approaches said cover when ink is being supplied by the ink supply, said ink supply comprising:

a container and a valve mechanism attached to said container, said valve mechanism comprising:

a cap having a planar top control surface; a third opening through said planar top control surface, said third opening being alignable with said second opening to permit the flow of ink from the ink supply through the second opening and third opening when the ink supply is coupled to said base, and a threaded periphery for engaging said neck and advancing said cap through said neck toward said shoulder by rotation of said cap, said threaded periphery having an axial length extending from a first predetermined position adjacent said container to a second predetermined position adjacent said planar top control surface, wherein the threads on said threaded periphery extend around said periphery and at least a portion of said axial length, whereby said cap is secured to said base, wherein said planar top control surface is constructed in a predetermined relation to said threaded periphery such that said planar top control surface engages and abuts said shoulder portion of said base when the ink supply is mounted thereon;

a movable valve member juxtaposed to said third opening and closing said third opening prior to coupling said ink supply to said ink jet system by rotation of said cap;

a resilient member in contact with said valve member and being under compression to resist movement of the movable valve member prior to mounting of the ink supply onto said ink jet system, said movable valve member and resilient member operatively coupled to said cap; and

a projection, concentric with said third opening, having an axial length less than the axial length of said threaded periphery and extending from said planar top control surface, said projection extending into said reservoir and being exposed to said surface of said ink when said ink supply is fully mounted on said base such that the planar top control surface abuts said shoulder portion and said projection is concentric with said second opening, said projection having a diameter less than the diameter of the periphery and having an extremity that is free of contact with said base when the ink supply is mounted on said base, whereby ink is permitted to flow from said ink supply, through said projection and into said reservoir;

wherein, when said ink supply is fully mounted on said base and secured thereto by engagement of said threaded periphery of the cap with the threaded inner surface of the neck, said planar top control surface of said cap abuts said shoulder portion and said projection extends into said reservoir a predetermined distance with said valve member being in an open position to permit ink to flow from said ink supply into said reservoir;

wherein said valve mechanism engages said ink jet system when the ink supply is mounted on the ink jet system and causes relative movement between said third opening and said movable valve member by overcoming the resistance to movement of said valve member by said resilient member;

wherein said planar top control surface of said cap extends in a single plane from said periphery to said projection; and

wherein said movable valve member is movable between a closed position and said open position, and is completely contained within said valve mechanism and container when in said closed position, whereby said valve member remains free of contact with said top surface of ink in the reservoir.

2. The ink supply of claim 1 wherein said base further includes a valve actuating member situated within said reservoir beneath said second opening, said valve actuating member having a pointed tip portion, and wherein said valve mechanism includes an actuating surface operatively coupled to said movable valve member, said actuating surface being concave so as to fit said actuating member.

3. The ink supply of claim 2 wherein said actuating surface is located within said third opening.

4. The ink supply of claim 2 wherein said actuating surface is concentric with said third opening.

5. The ink supply of claim 4 wherein said actuating surface is within said third opening.

6. The ink supply of claim 2 wherein said actuating surface is located adjacent but spaced from the extremity of said projection.

7. The ink supply of claim 6 wherein said actuating surface is located within said third opening.

8. The ink supply of claim 2 wherein said actuating surface moves with said movable valve member.

9. The ink supply of claim 1 wherein said resilient member is compressed in a direction parallel with a direction of ink flow through the third opening.

10. The ink supply of claim 9 wherein said resilient member is a coiled spring.

11. An ink supply for an impulse ink jet supply apparatus used in an impulse ink jet system, said impulse ink jet system including a base having a reservoir for holding ink, a cover enclosing said reservoir, a neck having a first opening and extending upwardly from said cover and having a threaded inner surface for engaging the ink supply when the ink supply is inserted within the first opening within the neck, said cover having a second opening that is concentric with and below said neck and said first opening to permit ink to flow from the ink supply, through the second opening and into said reservoir, wherein a flat shoulder portion of said cover surrounds said second opening and stops further insertion of said ink supply once said ink supply is fully mounted on said base such that the ink supply abuts said shoulder portion, said ink supply comprising:

a container;

a cap having a threaded outer surface for engaging said threaded inner surface of said neck of said ink jet system and advancing said ink supply toward said shoulder by rotation of said cap, and a threaded inner surface whereby said cap is threadably coupled to said container, and having an internal cavity receiving the container, said cap further having a transverse extremity and a dispensing opening through said extremity and in communication with said cavity, wherein said transverse extremity engages and abuts said shoulder portion of said base when the ink supply is mounted thereon;

a valve member located within said cavity and in communication with said dispensing opening, said valve member movable with respect to said dispensing opening between a closed position for preventing flow of ink from said container to said dispensing opening and an open position permitting flow of ink from said container to said dispensing opening; and

a resilient member located within said cavity juxtaposed to said valve member for maintaining said valve member in the closed position prior to mounting said ink supply in the ink jet system and permitting said valve member to move to the open position after mounting on the ink jet system;

wherein said cap further comprises a projection that extends from said transverse extremity and is concentric with said dispensing opening, said projection extending into the ink jet system reservoir and being adjacent to an ink level therein when said cap is screwed into said threaded neck and said transverse extremity abuts said shoulder;

wherein said transverse extremity of said cap extends in a single plane from said threaded outer surface to said projection; and

wherein said threaded outer surface of said cap has a first axial length extending from a first predetermined position adjacent said container to a second predetermined position adjacent said transverse extremity, wherein the threads on said outer surface extend around said outer surface and at least a portion of said first axial length;

wherein said projection has a second axial length which is less than said first axial length of said threaded outer surface, and wherein said projection has a diameter that is less than the diameter of the outer surface;

wherein, when said ink supply is fully mounted on said base and secured thereto by engagement of said threaded outer surface of the cap with the threaded inner surface of the neck, said extremity of said cap abuts said shoulder portion and said projection extends into said reservoir a predetermined distance with said valve member being in an open position to permit ink to flow from said ink supply into said reservoir, whereby a predetermined level of ink is maintained in said reservoir; and

wherein said valve member is completely contained within said cap and container when in said closed position.

12. The ink supply of claim 11 wherein said resilient member is concentric with the cavity.

13. The ink supply of claim 11 wherein said resilient member is concentric with said dispensing opening.

14. The ink supply of claim 11 wherein said resilient member is compressed in a direction parallel with a direction of ink flow through the dispensing opening.

15. The ink supply of claim 14 wherein said resilient member is a coiled spring.

16. A combination comprising:

(a) an impulse ink jet system including a base having a reservoir for holding ink, a cover enclosing said reservoir, a neck extending upwardly from said cover and having a threaded inner surface for engaging an ink supply when said ink supply is inserted within a first opening within the neck, said cover having a second opening that is concentric with and below said neck and said first opening to permit ink to flow from said ink supply, through the second opening and into said reservoir, wherein an axially transverse shoulder portion of said cover surrounds said second opening and controls said ink supply by stopping further insertion of said ink supply once said ink supply is fully mounted on said base such that the ink supply abuts said shoulder portion, wherein said ink has a top surface that approaches said cover when ink is being supplied by the ink supply; and

(b) said ink supply storing ink jet ink for use in said ink let system and being adapted for coupling to said ink jet system and comprising:

a container; and

a cap coupled to said container and having a top control surface extending substantially parallel to said shoulder when said cap and container are coupled to said neck, said top control surface engaging said shoulder portion of said base when the ink supply is mounted thereon so as to control the position of said cap in said neck; a third opening disposed within said top control surface and alignable with said second opening to permit the flow of ink from the ink supply through the second opening and third opening and into said reservoir; and a threaded periphery for engaging said neck and advancing said cap through said neck toward said shoulder, whereby said cap is secured to said base; and a projection extending from said top control surface, said projection being concentric with said third opening and extending from said top control surface and into said reservoir and being exposed to the surface of said ink when said ink supply is fully mounted on said base such that the top control surface abuts said shoulder portion and said projection extends a predetermined distance into said reservoir, said projection having an extremity that is free of contact with said base when the ink supply is mounted on said base, whereby ink is permitted to flow from said ink supply, through said projection and into said reservoir, wherein said top control surface of said cap extends in a single plane from said threaded periphery to said projection;

a movable valve member coupled to said cap, said movable valve member being juxtaposed to said third opening and closing said third opening prior to coupling said ink supply to said ink jet system;

a resilient member in contact with and supported by said movable valve member and said cap and being under compression to resist movement of the movable valve member prior to mounting of the ink supply onto said ink jet system;

wherein said threaded periphery of said cap is constructed so as to cooperate with said threaded inner surface of said neck so as to rotate said cap in said neck to axially advance said top control surface toward said shoulder such that, when said ink supply is fully mounted on said base following rotation of said cap, said top control surface of said cap abuts said shoulder portion to prevent further axial advance, whereby said projection extends into said reservoir to a predetermined and positively controlled position within said reservoir with said movable valve member being in an open position to permit ink to flow from said ink supply into said reservoir and to achieve a predetermined and positively controlled level of ink within said reservoir;

wherein said movable valve member is completely contained within said cap and container when in said closed position; and

wherein said threaded periphery of said cap has a first axial length extending from a first predetermined position adjacent said container to a second predetermined position adjacent said control surface, the threads on said threaded periphery extending around said periphery and at least a portion of said first axial length, said projection having a second axial length which is less than said first axial length.

17. A combination as recited in claim 16, further comprising an actuating surface operatively coupled to said movable valve member and, when the ink supply is mounted on the ink jet system, engaging said ink jet system and causing relative movement between said third opening and said movable valve member by overcoming the resistance to movement of said valve member by said resilient member.

18. A combination as recited in claim 17, wherein said actuating surface is located within said third opening.

19. A combination as recited in claim 17, wherein said actuating surface is located adjacent but spaced from the extremity of said projection.

20. A combination as recited in claim 19, wherein said actuating surface is located within said third opening.

21. A combination as recited in claim 17, wherein said actuating surface is concentric with said third opening.

22. A combination as recited in claim 21, wherein said actuating surface is within said third opening.