Patent Application
20150002582
Drop-on-demand inkjet printers are commonly categorized according to one of two mechanisms of drop formation within an inkjet printhead. Thermal inkjet printers may use inkjet printheads with heating element actuators that vaporize ink, or other print fluid, inside ink-filled chambers to create bubbles that force ink droplets out of the printhead nozzles. Piezoelectric inkjet printers may use inkjet printheads with piezoelectric ceramic actuators that generate pressure pulses inside ink-filled chambers to force droplets of the ink out of the printhead nozzles.
The Detailed Description section references the drawings, wherein:
Inkjet printheads may include a common fluid supply channel that provides a source of ink for a plurality of firing chambers for ejecting a fluid, such as ink, from the printhead through corresponding nozzles. When a nozzle is fired, the advance portion of the pressure wave may direct ink toward the nozzle for ejection, while the retrograde portion of the pressure wave may direct ink back toward the common fluid supply channel. Sometimes, a considerable dynamic pressure may develop in the common fluid supply channel, especially in cases in which the dimension of the common fluid supply channel is relatively small. This dynamic pressure may result, for example, in diminished printhead stability and fluidic cross-talk across the firing chambers/nozzles fluidly coupled to the common ink supply channel.
In some cases, a common fluid supply channel may include a thin flexible membrane to counter transient pressure changes. The membrane may be disposed between the common fluid supply channel and a cavity, and may flex into the cavity upon increased pressure within the common fluid supply channel or flex into the common fluid supply channel (and away from the cavity) upon decreased pressure within the common fluid supply channel. In addition to the complexity of incorporating the membrane and cavity into the printhead structure, and possibility of damaging the membrane during fabrication, the membrane/cavity structure typically requires venting to accommodate the flexing of the membrane and this may add further complexity to the fabrication. In addition, the membranes may stretch or tear, which may impact the performance of the printhead. In some cases, a pin hole may develop in the membrane, allowing fluid to seep into the cavity and resulting in decreased performance of the printhead or failure altogether.
Described herein are embodiments of fluid ejection apparatuses including a compressible material forming, at least in part, a wall of a common fluid supply channel. Various implementations may provide a robust structure that incurs little or no stretching or tearing on transient high-pressure events, may incur little or no performance impact should the compressible material develop a pin hole, or may avoid complicated fabrication techniques such as venting.
An example fluid ejection apparatus 100 is illustrated in
The compressible material 106 may be configured to alleviate pressure surges from pulsing fluid flows through the fluid ejection apparatus 100 due to start-up transients, nozzle firing or priming, and fluid ejections in adjacent nozzles, for example. In various implementations, the compressible material 106 may comprise a material having a property of compressing in response to an increase in pressure in the coma on fluid supply channel 104. Transient increases in pressure in the common fluid supply channel 104 may occur, for example, when the nozzles are fired or primed. The compressible material 106 may also have a property of expanding in respond to a decrease in pressure in the common fluid supply channel 104. Transient decreases in pressure in the common fluid supply channel 104 may occur, for example, during operation as the firing chamber (not illustrated here), coupled between one of the nozzles 102 and the common fluid supply channel 104, draws ink or other printing fluid from the common fluid supply channel 104. In various implementations, the compressibility and/or expandability of the compressible material 106 may have a dampening effect on fluidic cross-talk between adjacent nozzles as well as act as a reservoir to ensure fluid is available while flow is established from the fluid supply during high-volume printing, for example.
The apparatus 200 may include an ejector structure 208, which may include the plurality of nozzles 202. The ejector structure 208 may be coupled to a substrate die 210 such that a compressible material 206 is between the ejector structure 206 and the substrate die 210, as illustrated. The compressible material 206 may form, at least in part, a wall of a common fluid supply channel (not illustrated here), which may or may not be part of the ejector structure 208. Although not illustrated here, in various implementations, the apparatus 200 may also include firing chambers fluidly coupling corresponding ones of the nozzles 202 to the common fluid supply channel, and actuators configured to deflect into a corresponding one of the firing chambers to cause fluid to be ejected through a corresponding one of the nozzles 202.
In various implementations, the substrate die 210 may comprise silicon or another substrate. In various implementations, the compressible material 206 may comprise a polymer, an elastomer, a foam, or a combination thereof. The compressible material 208 may substantially solid, with few, if any voids, other than those that may be present in the closed-cells of the material. Examples of suitable materials for the compressible material 206 may include, but are not limited to, silicone rubber, closed-cell solid foams, silicone foams, and fluoro-silicone foams. Other materials may be similarly suitable in some implementations.
The compressible material 206 may have a compliance value to allow for compressing in response to an increase in pressure in the common fluid supply channel or compressing in response to an increase in pressure in the common fluid supply channel and expanding in response to a decrease in pressure in the common fluid supply channel. In various implementations, the compressible material 206 may comprise a material having a compliance value of up to about 7×10−15 m3/Pa (this may correspond, e.g., to a compression of about 25% with a load in a range between about 2 psi and about 7 psi for a 0.5 Mill×22 mm×0.7 mm layer of material). In some of these implementations, the compressible material may comprise a soft silicone rubber closed-cell foam layer. In some implementations, the compressible material 206 may comprise a material having a compliance value of at least about 2×10−15 m3/Pa. In some implementations, the compressible material 206 may comprise a material having a compliance value of at least about 2.5×10−15 m3/Pa.
In various implementations, the compressible material 206 may have a thickness in a range of about 0.1 microns to about 10 microns. In some examples, the compressible material 106 has a thickness in a range of about 3 microns to about 10 microns. Other thicknesses may be suitable for a number of other implementations within the scope of the present disclosure.
The ejector structure 208 may include circuitry 212 for driving one or more of the actuators of the ejector structure 208. In various implementations, the ejector structure 208 may comprise a multilayer micro-electro-mechanical system (MEMS) die stack. In various implementations, the ejector structure 208 may be formed of at least in part, of silicon or another material.
The controller 316 may be configured to control ejection of fluid by the printhead assembly 314. In various implementations, the controller 316 may comprise one or more processors, firmware, software, one or more memory components including volatile and non-volatile memory components, or other printer electronics for communicating with and controlling the printhead assembly 314. The controller 316 may be configured to communicate with and control one or more other components such as, but not limited to, a mounting assembly (not illustrated) to position the printhead assembly 314 relative to a media transport assembly (not illustrated), which may position a print media relative to the print head assembly 314.
In some implementations, the controller 316 may control the printhead assembly 314 for ejection of ink drops from one or more of the nozzles 302. The controller 316 may define a pattern of ejected ink drops that form characters or images onto a medium. The pattern of ejected ink drops may be determined by a print job command and/or command parameter from data, which may be provided by a host system to the controller 316.
The fluid supply 318 may supply fluid to the printhead assembly 314. In some implementations, the fluid supply 318 may be included in the printhead assembly 314, rather than separate as Illustrated. In various implementations, the fluid supply 318 and the printhead assembly 314 may form either a one-way ink delivery system or a recirculating ink delivery system. In a one-way ink delivery system, substantially all of the ink supplied to inkjet printhead assembly 314 may be consumed during printing. In a recirculating ink delivery system, however, only a portion of the ink supplied to the printhead assembly 314 may be consumed during printing and ink not consumed during printing may be returned to the fluid supply 318.
In some implementations, a sheet of the compressible material 406 may be coupled to the substrate the 410, cut to a dimension suitable for the configuration of the fluid ejection apparatus, and coupled to an ejector structure including the common fluid supply channel (illustrated and discussed elsewhere). In some implementations, the sheet of compressible material 406 may be cut to a suitable dimension before coupling to the substrate the 410. In other implementations, the compressible material 406 may be fabricated by curing a pre-cursor of the compressible material. In some of these implementations, the pre-cursor may be applied directly onto a pre-formed common fluid supply channel.
In various implementations, the first layer 522 may have a thickness in a range of about 0.1 microns to about 10 microns, and the second layer 524 may have a thickness in a range of about 0.05 microns to about 0.5 microns. Other thicknesses for the first layer 522 and the second layer 524 may be suitable for a number of other implementations within the scope of the present disclosure.
In various implementations, the first layer 522 and/or the second layer 524 may comprise a polymer, an elastomer, a foam, or a combination thereof. Examples of suitable materials for the first layer 522 may include, but are not limited to, silicone rubber, closed-cell solid foams, silicone foams (such as, e.g., fluoro-silicone foams). In some implementations, the first layer 522 may comprise a polymer, an elastomer, a foam, or a combination thereof, and the second layer 524 may comprise a metal or inorganic material applied to the first layer 522. Other materials may be similarly suitable in some implementations. In some implementations, the second layer 524 may be applied to the first layer 522 using a suitable deposition operation such as, for example, atomic layer deposition, a chemical vapor deposition operation, or the like.
It is noted that although the compressible material 506 is illustrated as comprising the second layer 524 completely surrounding the first layer 522, other configurations may be possible. For example, in some implementations, the second layer 524 may be formed on a single or fewer than all sides of the first layer 522.
The plurality of nozzles 602 and the common fluid supply channel 604 may form, at least in part, an ejector structure 608. In various implementations, the apparatus 600 may include a substrate die 610 arranged such that the compressible material 606 is between the ejector structure 608 and the substrate die 610. As illustrated, a first surface 625 of the compressible material 606 abuts against the substrate die 610, and a second surface 627, opposite the first surface, faces the common fluid supply channel 604.
In some implementations, the ejector structure 608 may be formed, at least in part, of silicon. In some implementations, the nozzle layer 626 may be formed stainless steel or chemically-inert polymer such as, for example, polyimide or SU8 photoresist. The layers of the ejector structure 608 may be integral or may be bonded together with an adhesive (not illustrated). In various implementations, the ejector structure 608 may comprise a multilayer micro-electro-mechanical system (MEMS) die stack, which may include drive circuitry for driving one or more of a plurality of actuators 628 of the ejector structure 608.
As illustrated, each of the plurality of nozzles 602 is in fluid communication with at least one of a plurality of firing chambers 630. The plurality of actuators 628 may be configured to deflect into a corresponding one of the firing chambers 630 to cause fluid to be ejected through a corresponding one of the nozzles 602. In some implementations, the actuators 628 may comprise piezoelectric actuators. Other types of actuators such as, for example, heating elements or other actuators may be used for the actuators 628 in other implementations within the scope of the present disclosure.
The apparatus 600 may include a plurality of ports 632, 634 fluid coupling the common fluid supply channel 604 to the individual firing chambers 630. In some implementations, at least one of the ports 632, 634 may include restrictors 644 protruding into the openings defined by the ports 632, 634. As illustrated, the restrictors 644 comprise pairs of protrusions configured to control a flow rate of fluid between the common fluid supply channel 604 and the firing chambers 630. In various implementations, the restrictors 644 may have varying sizes (i.e., protrusion into the openings defined by the ports 632, 634) to control a flow rate. In other implementations, one or more of the individual restrictors 644 may be omitted altogether.
In some implementations, one of the ports 632 may configured to provide fluid to the firing chamber 630 from the common fluid supply channel 604, and the other one of the ports 634 may be configured to separately provide fluid to the firing chamber 630 from another channel 636. The other channel 636 may comprise another common fluid supply channel similarly configured to the common fluid supply channel 604, with the compressible material 606 forming, at least in part, a wall of the other channel 636. As illustrated, the same sheet or layer of compressible material 606 may form, at least in part, the walls of both the common fluid supply channel 604 and the other channel 636.
In other implementations, the other channel 636 may comprise an exit manifold such that fluid may be circulated through the firing chamber 630, with one of the ports 632 forming an inlet to the firing chamber 630 and the other one of the ports 634 forming an outlet from the firing chamber 630. In various implementations, the fluid may be circulated by external pumps of a fluid supply (not illustrated here).
The substrate die 710 may include at least one recess 738 such that the compressible material 706 is between the recess 738 and the common fluid supply channel 704, as illustrated. In various ones of these implementations, the compressible material 706 may include at least one opening 740 fluidly coupling the common fluid supply channel 704 to the recess 738. In this configuration, the recess 738 may form, least in part, a second common fluid supply channel. In various ones of these implementations, fluid may be provided to the common fluid supply channel 704 via the recess 738, In some of these embodiments, the fluid may be provided to the substrate die 710 (by a through-slot or through an end of the substrate die 710, for example).
As illustrated, the recess 838 in the substrate the 810 may include a plurality of posts 842. The post 842 may support the compressible material 806 to limit deformation of the compressible material 806 into the recess 838 to allow the compressible material 806 to compress. In various implementations, the compressible material 806 may be coupled to the posts 842 with an adhesive, for example. In some implementations, the compressible material 806 may not be coupled to the posts 842.
In various implementations, the apparatus 800 may include the compressible material 706 described herein with reference to
The substrate the 910 may include the common fluid supply channel 904, as illustrated, such that the compressible material 906 is between the ejector structure 908 and at least a portion of the common fluid supply channel 904, as illustrated. The compressible material 906 may include at least one opening 940 fluidly coupling the common fluid supply channel 904 to the firing chamber 930. In various ones of these implementations, fluid may be provided to the common fluid supply channel 904 via the recess 938. In some of these embodiments, the fluid may be provided to the substrate die 910 (by a through-slot or through an end of the substrate die 910, for example).
The common fluid supply channel 1004 may be fluidly coupled to the individual firing chambers 1030 by ports 1032. As illustrated, the ports 1032 have a passageway opening that is smaller than those of the firing chambers 1030 (as illustrated, width, depth, and length are smaller). In various implementations, the dimensions of the ports 1032 may be configured to control a flow rate of fluid between the common fluid supply channel 1004 and the firing chambers 1024. In other implementations, the ports 1032 may include one or more dimensions substantially the same as the firing chambers 1030 and/or the common fluid supply channel 1004.
As illustrated, the compressible material 1206 may extend along the common fluid supply channel 1202. Rather than on the bottom wall of the common fluid supply channel 1204 as in the implementation described herein with reference to FIG. 10A/10B, the compressible material 1206 may instead be disposed on a side wall of the common fluid supply channel 1202 opposite the ports 1232, as illustrated. In various non-illustrated implementations, the compressible material 1206 may extend along multiple walls of the common fluid supply channel 1204 (such as, e.g., the bottom wall and a side wall).
Various aspects of the illustrative embodiments are described herein using terms commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. It will be apparent to those skilled in the art that alternate embodiments may be practiced with only some of the described aspects. For purposes of explanation, specific numbers, materials, and configurations are set forth in order to provide a thorough understanding of the illustrative embodiments. It will be apparent to one skilled in the art that alternate embodiments may be practiced without the specific details. In other instances, well-known features are omitted or simplified in order not to obscure the illustrative embodiments.
The phrases “in an example,” “in various examples,” “in some examples,” “in various embodiments,” and “in some embodiments” are used repeatedly, The phrases generally do not refer to the same embodiments; however, they may. The terms “comprising,” “having,” and “including” are synonymous, unless the context dictates otherwise. The phrase “A and/or B” means (A), (B), or (A and B). The phrase “A/B” means (A), (B), or (A and B), similar to the phrase “A and/or B”. The phrase “at least one of A, B, and C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C). The phrase “(A) B” means (B) or (A and B), that is, A is optional. Usage of terms like “top”, “bottom”, and “side” are to assist in understanding, and they are not to be construed to be limiting on the disclosure.
Although certain embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope of this disclosure. Those with skill in the art will readily appreciate that embodiments may be implemented in a wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. It is manifestly intended, therefore, that embodiments be limited only by the claims and the equivalents thereof.
