Design method and design tool for a print head, print head and jetting device

Abstract

Printheads and manifolds within printheads. In one implementation, a method includes determining a resonant frequency of a firing channel of a printhead, and selecting a target length of a manifold fluidically coupled to the firing channel such that a resonant frequency of the manifold differs from the resonant frequency of the firing channel by a threshold amount.

Description

Technical Field

[0001] The following disclosure pertains to the field of image formation, and in particular to printheads and printhead design. Background Technology

[0002] Image formation is the process of reconstructing a digital image by propelling droplets of ink or another type of printing fluid onto a medium, such as paper, plastic, a substrate for 3D printing, etc. Image formation is commonly used in devices such as printers (e.g., inkjet printers), fax machines, copiers, plotters, multifunction peripherals, etc. At the heart of a typical jetting or image forming apparatus is one or more droplet ejection heads (generally referred to here as "printheads"), which have nozzles for discharging droplets, mechanisms for moving the printhead and / or the medium relative to each other, and controllers for controlling how the liquid is discharged from the individual nozzles of the printhead onto the medium in pixel form.

[0003] A typical printhead contains multiple nozzles arranged in one or more rows along the ejection surface of the printhead. Each nozzle is part of an "ejection channel," which includes a nozzle, a pressure chamber, and a diaphragm that vibrates in response to an actuator (such as a piezoelectric actuator). The printhead also includes driver circuitry that controls when each individual ejection channel is activated based on image or print data. To eject from the ejection channel, the driver circuitry provides ejection pulses to the actuator, causing the actuator to deform the wall (i.e., the diaphragm) of the pressure chamber. The deformation of the pressure chamber generates pressure waves within the pressure chamber, which eject droplets of printing fluid (e.g., ink) from the nozzle.

[0004] Multiple jet channels within the printhead are fluidly coupled to a common fluid path that transports the printing fluid, known as a manifold. One problem encountered in the printhead is that pressure waves can escape from the jet channels and propagate along the manifold. Pressure waves in the manifold can affect the jetting in individual jet channels, leading to jetting instability. Summary of the Invention

[0005] The embodiments described herein provide a printhead with a manifold of a target length and a printhead design. If the manifold in the printhead vibrates at the same frequency as the jet channels in the printhead, the manifold vibration can excite pressure waves escaping from the jet channels within the manifold. Unfortunately, this can cause channel-to-channel jetting performance differences. Therefore, the length of the manifold in the printhead is chosen such that its resonant frequency differs from the resonant frequency of the jet channels. One technical advantage of choosing the manifold length in this way is that manifold vibration will not excite pressure waves escaping from the jet channels and propagating within the manifold, thus improving jetting consistency and performance.

[0006] One embodiment includes a method comprising determining the resonant frequency of an ejection channel of a printhead and selecting a target length of a manifold fluidly coupled to the ejection channel such that the resonant frequency of the manifold differs from the resonant frequency of the ejection channel by a threshold amount.

[0007] Another embodiment includes a design tool for a printhead. The design tool includes at least one processor and memory, which enable the design tool to determine the resonant frequency of the jet channel of the printhead and select a target length of a manifold fluidly coupled to the jet channel such that the resonant frequency of the manifold differs from the resonant frequency of the jet channel by a threshold amount.

[0008] Another embodiment includes a printhead comprising multiple jet channels and a manifold fluidly coupled to the jet channels. The length of the manifold is selected to produce a resonant frequency that differs from the resonant frequency of the jet channels by a threshold amount.

[0009] The above summary provides a basic understanding of certain aspects of the specification. This summary is not a complete overview of the specification. It is neither intended to identify key or essential elements of the specification, nor to depict any scope of the specification, specific embodiments, or any scope of the claims. Its sole purpose is to present some concepts of this specification in a simplified form as a prelude to the more detailed descriptions that follow. Attached Figure Description

[0010] Some embodiments of this disclosure will now be described by way of example only and with reference to the accompanying drawings. Throughout the drawings, the same reference numerals denote the same elements or elements of the same type.

[0011] [ Figure 1 ]

[0012] Figure 1 This is a schematic diagram of the spraying device in an illustrative embodiment.

[0013] [ Figure 2 ]

[0014] Figure 2 This is a perspective view of the printhead in the illustrative embodiment.

[0015] [ Figure 3 ]

[0016] Figure 3 This is a schematic diagram of the jetting channel within the printhead in an illustrative embodiment.

[0017] [ Figure 4 ]

[0018] Figure 4 This is another schematic diagram of the jetting channel within the printhead in the illustrative embodiment.

[0019] [ Figure 5]

[0020] Figure 5 This is a schematic diagram of the printhead in an illustrative embodiment.

[0021] [ Figure 6 ]

[0022] Figure 6 An exploded perspective view of the head component of the printhead in an illustrative embodiment is shown.

[0023] [ Figure 7 ]

[0024] Figure 7 This is a perspective view of the head component in an illustrative embodiment.

[0025] [ Figure 8 ]

[0026] Figure 8 The jet pulses representing the drive waveform for the printhead are shown in an illustrative embodiment.

[0027] [ Figure 9 ]

[0028] Figure 9 Pressure waves in the pressure chamber of the jet channel in an illustrative embodiment are shown.

[0029] [ Figure 10 ]

[0030] Figure 10 This is a cross-sectional view of the printhead in the illustrative embodiment.

[0031] [ Figure 11 ]

[0032] Figure 11 This is a schematic diagram of a design tool for a printhead in an illustrative embodiment.

[0033] [ Figure 12 ]

[0034] Figure 12 This is a flowchart illustrating a method for designing a printhead in an illustrative embodiment.

[0035] [ Figure 13 ]

[0036] Figure 13 This is a cross-sectional view of a printhead with an extender in an illustrative embodiment.

[0037] [ Figure 14 ]

[0038] Figure 14 This is a schematic diagram of the printhead in an illustrative embodiment.

[0039] [ Figure 15 ]

[0040] Figure 15 This is a cross-sectional view of the printhead in an illustrative embodiment.

[0041] [ Figure 16 ]

[0042] Figure 16 A processing system operable in an illustrative embodiment is shown that can execute a computer-readable medium embodying programmed instructions to perform desired functions. Detailed Implementation

[0043] The accompanying drawings and the following description illustrate specific exemplary embodiments. Therefore, it should be understood that those skilled in the art will be able to design various arrangements, which, although not explicitly described or shown herein, embody the principles of the embodiments and are included within the scope of the embodiments. Furthermore, any examples described herein are intended to aid in understanding the principles of the embodiments and should be construed as not being limited to these specifically enumerated examples and conditions. Therefore, the inventive concept is not limited to the specific embodiments or examples described below, but is defined by the claims and their equivalents.

[0044] Figure 1 This is a schematic diagram of an ejector device 100 in an illustrative embodiment. The ejector device 100 is a device or system that uses one or more printheads to eject printing fluid or marking material onto a medium. One example of an ejector device 100 is an inkjet printer that performs single-pass printing (e.g., a single-page or continuous feed printer). Other examples of ejector devices 100 include scanning inkjet printers (e.g., wide-format printers), multifunction printers, desktop printers, industrial printers, 3D printers, etc. Typically, the ejector device 100 includes a mounting mechanism 102 that supports one or more printheads 104 relative to a medium 112. The mounting mechanism 102 may be secured within the ejector device 100 for single-pass printing. Alternatively, the mounting mechanism 102 may be disposed on a carriage assembly that reciprocates along a scan line or sub-scan direction for multi-pass printing. The printhead 104 is configured to pass through multiple nozzles (in... Figure 1An apparatus, device, or component that ejects droplets 106 of a printing fluid, such as ink (e.g., water, solvent, oil, or UV-curable), invisible from the nozzles of a printhead 104. The droplets 106 ejected from the nozzles of a printhead 104 are directed to a medium 112. The medium 112 comprises any type of material to which ink or another marking material is applied by the printhead, such as paper, plastic, card material, transparent sheet, substrate for 3D printing, fabric, etc. Typically, the nozzles of the printhead 104 are arranged in one or more rows such that, as the printhead 104 and / or the medium 112 move relative to each other, the printing fluid is ejected from the nozzles to form characters, symbols, images, object layers, etc., on the medium 112. The ejection device 100 may include a media transport mechanism 114 or a media holding bed 116. The media transport mechanism 114 is configured to move the medium 112 relative to the printhead 104. The media holding bed 116 is configured to support the medium 112 in a fixed position as the printhead 104 moves relative to the medium 112.

[0045] The jetting device 100 also includes a jetting device controller 122, which controls the overall operation of the jetting device 100. The jetting device controller 122 can be connected to a data source to receive print data, image data, etc., and controls each printhead 104 to discharge print fluid onto the media 112. The jetting device 100 also includes one or more reservoirs 124 for print fluid. Although in Figure 1 It is not shown in the figure, but the reservoir 124 is fluidly coupled to the printhead 104 by means of, for example, a hose.

[0046] Figure 2 This is a perspective view of a printhead 104 in an illustrative embodiment. In this embodiment, the printhead 104 includes a head member 202 and electronics 204. The head member 202 is an elongated assembly forming an ejection channel of the printhead 104. A typical ejection channel includes a nozzle, a pressure chamber, and a diaphragm driven by an actuator (e.g., a piezoelectric actuator). The electronics 204 controls how the nozzle of the printhead 104 ejects droplets in response to data signals and control signals. Although in Figure 2 While not visible in the image, electronics 204 may include one or more driver circuits configured to drive actuators (e.g., piezoelectric actuators) that contact the diaphragm of the ejection channel. Electronics 204 is connected to a controller (e.g., ejection device controller 122) to receive data and control signals. The controller is configured to provide data and control signals to printhead 104 to control the ejection of individual ejection channels, control the temperature of printhead 104, etc.

[0047] Figure 2 The lower surface of the head component 202 includes the nozzle of the jet channel and represents the discharge surface 220 of the printhead 104. Figure 2The upper surface of the printhead member 202 (referred to as I / O surface 222) represents an input / output (I / O) portion for receiving one or more print fluids into the printhead 104 and / or delivering print fluid (e.g., non-ejected fluid) out of the printhead 104. I / O surface 222 includes a plurality of I / O ports 211-214. I / O ports 211-214 may include inlet I / O ports, which are openings in the printhead member 202 serving as inlet points for the print fluid. I / O ports 211-214 may include outlet I / O ports, which are openings in the printhead member 202 serving as outlet points for the print fluid. I / O ports 211-214 may include hose connectors, hose barbs, etc., for connection to hoses such as reservoirs, ink cartridges, etc. The number of I / O ports 211-214 is provided as an example, as the printhead 104 may include other numbers of I / O ports.

[0048] The head assembly 202 includes a housing 230 and a plate stack 232. The housing 230 is a rigid member made of stainless steel or other types of material. The housing 230 includes an inlet 234 that provides a passage for the electronics 204 to pass through the housing 230, allowing the actuator to engage (i.e., contact) with the diaphragm of the injection channel. The plate stack 232 is attached to an engagement surface (not visible) of the housing 230. The plate stack 232 (also referred to as a laminate stack) is a series of plates fixed or joined together to form a laminate stack. The plate stack 232 may include one or more nozzle plates, one or more chamber plates, one or more flow restrictors, and diaphragm plates. The nozzle plates include a plurality of nozzles arranged in one or more rows (e.g., two rows, four rows, etc.). The chamber plates include a plurality of openings forming a pressure chamber of the injection channel. The flow restrictors include a plurality of flow restrictors fluidly connecting the pressure chamber of the injection channel to the manifold. The diaphragm is a semi-flexible sheet of material that vibrates in response to actuation by an actuator (e.g., a piezoelectric actuator).

[0049] Figure 2 The embodiments shown herein illustrate a particular configuration of printhead 104, and it should be understood that other printhead configurations with multiple jet channels are considered herein.

[0050] Figure 3 This is a schematic diagram of the jet channels 302 within the printhead 104 in an illustrative embodiment. The diagram represents a view along the length of the printhead 104. The jet channels 302 are structural elements within the printhead 104 that jet or eject printing fluid. Each jet channel 302 includes a diaphragm 310, a pressure chamber 312, and a nozzle 314. An actuator 316 contacts the diaphragm 310 to control the jetting from the jet channels 302. The jet channels 302 may form one or more rows along the length of the printhead 104, and each jet channel 302 may have a similar shape to... Figure 3The configuration shown.

[0051] Figure 4 This is another schematic diagram of the jet channel 302 within the printhead 104 in the illustrative embodiment. Figure 4 The view shown is a cross-section of the jet passage 302 spanning a portion of the width of the printhead 104. A pressure chamber 312 is fluidly coupled to a manifold 418 via a flow restrictor 420. The flow restrictor 420 controls the flow of printing fluid from the manifold 418 to the pressure chamber 312. One wall of the pressure chamber 312 is formed by a diaphragm 310 physically engaged with an actuator 316. The diaphragm 310 may include a semi-flexible sheet of material that vibrates in response to actuation of the actuator 316. In response to actuation of the actuator 316, printing fluid flows through the pressure chamber 312 and exits the nozzle 314 in the form of droplets. The actuator 316 is configured to receive jet pulses and to actuate or “fire” in response to the jet pulses. The firing of the actuator 316 in the jet passage 302 generates a pressure wave in the pressure chamber 312, which causes droplets to be ejected from the nozzle 314.

[0052] like Figure 3-4 The injection channel 302 shown is an example illustrating the basic structure of an injection channel, such as a diaphragm, pressure chamber, and nozzle. Other types of injection channels are also considered herein. For example, some injection channels may have the same characteristics as... Figure 3-4 The pressure chambers shown have different shapes. In other embodiments, the positions of the manifold 418, flow restrictor 420, diaphragm 310, etc., may be different.

[0053] Figure 5 This is a schematic diagram of the printhead 104 in an illustrative embodiment. The ejection channel 302 of the printhead 104 is... Figure 5 The nozzle 314 is schematically represented in two nozzle rows 501-502. Although nozzle 314 is in Figure 5 The nozzles are shown as staggered, but in other embodiments, the nozzles 314 in the nozzle rows 501-502 may be aligned. The printhead 104 (i.e., head member 202) includes a plurality of manifolds 418. The manifolds 418 are common fluid paths in the printhead 104 for the plurality of jet channels 302. The manifolds 418 that deliver print fluid to the plurality of jet channels 302 may also be referred to as "supply" manifolds. One of the manifolds 418 includes a fluid path between I / O ports 211-212 that is fluidly coupled to the nozzle rows.

[0054] The jetting channel 302 in nozzle row 501. Therefore, the printing fluid supplied at I / O ports 211 and / or I / O ports 212 is delivered via manifold 418 to the jetting channel 302 in nozzle row 501. Another fluid path in manifold 418 includes I / O ports 213-214, which is fluidly coupled to the jetting channel 302 in nozzle row 502. Therefore, the printing fluid supplied at I / O ports 213 and / or I / O ports 214 is delivered via manifold 418 to the jetting channel 302 in nozzle row 502. Although Figure 5 Two manifolds 418 are shown, but the printhead 104 can include more or fewer manifolds as needed.

[0055] Figure 6 An exploded perspective view of the head component 202 of the printhead 104 in an illustrative embodiment is shown. Figure 6 The illustration shows the basic structure of the head component 202, and the actual structure of the printhead 104 can be varied as needed. In this embodiment, the head component 202 is an assembly including a housing 230 and a plate stack 232. The plate stack 232 is fixed or attached to the housing 230 and forms one or more rows of jet channels 302. Figure 7 This is a perspective view of the head member 202 in an illustrative embodiment. Figure 7 In the middle, the plate stack 232 is attached or fixed to the outer shell 230.

[0056] exist Figure 6 In this embodiment, housing 230 is an elongated member made of a rigid material, such as stainless steel. Housing 230 has a length (L), width (W), and height (H), and the dimensions of housing 230 are such that the length is greater than the width. The orientation of a row of injection channels 302 corresponds to the length of housing 230. Housing 230 includes an inlet 234 at or near its center, extending from I / O surface 222 to an opposing engagement surface 612. Inlet 234 provides passage for actuator assemblies (e.g., multiple piezoelectric actuators) (not shown) to pass through and contact the diaphragm of the injection channels. Engagement surface 612 is the surface of housing 230 facing the plate stack 232 and is connected to the plates of plate stack 232. Housing 230 also includes one or more manifold conduits.

[0057] 616-617, which extend substantially along the length of the engagement surface 612. The manifold ducts 616-617 include elongated cuts or grooves along the engagement surface 612, which are configured to deliver printing fluid and form at least a portion of the manifold 418 of the printhead 104.

[0058] The plate stack 232 includes a series of plates 630-633, which are fixed or joined together to form a laminated plate structure. Figure 6The plate stack 232 shown is intended as an example of a basic structure for a printhead. It can have... Figure 6 Additional plates, not shown, are used for plate stack 232, and the structures of various plates can be varied as needed. Furthermore, Figure 6 It was not drawn to scale.

[0059] In this embodiment, the plate stack 232 includes the following plates: a diaphragm plate 630, a flow restrictor plate 631, a chamber plate 632, and a nozzle plate 633. The diaphragm plate 630 is a sheet material (e.g., metal, plastic, etc.) that is typically rectangular and substantially flat or planar. The diaphragm plate 630 includes a diaphragm portion 641 comprising a semi-flexible sheet of material forming a diaphragm 310 of the jet channel 302. The diaphragm portion 641 is longitudinally arranged to correspond to the pressure chamber. The diaphragm plate 641 may also include a filter portion 642, which is longitudinally arranged on the opposite side of the diaphragm portion 641 to coincide with manifold conduits 616-617. The filter portion 642 is configured to remove foreign matter from the printing fluid flowing in the jet channel 302 of the manifold. Although in this embodiment the diaphragm plate 630 is shown as including a diaphragm portion 641 and a filter portion 642, in other embodiments the diaphragm portion 641 and the filter portion 642 may be implemented in separate plates.

[0060] The flow restrictor plate 631 is a sheet material, typically rectangular, and substantially flat or planar. The flow restrictor plate 631 includes a flow restrictor opening 644, which is an elongated hole or aperture laterally disposed or oriented through the flow restrictor plate 631. The flow restrictor opening 644 is configured to fluidly couple the pressure chamber 312 of the injection passage 302 to the manifold.

[0061] The chamber plate 632 is a sheet material, which is generally rectangular and substantially flat or planar. The chamber plate 632 includes a chamber opening 646 disposed toward a central region of the chamber plate 632. The chamber opening 646 includes a hole or cavity through the chamber plate 632, which forms a pressure chamber 312 for the injection channel 302.

[0062] The nozzle plate 633 is a sheet material, typically rectangular, and substantially flat or planar. The nozzle plate 633 includes circular holes or openings 648 forming nozzles 314 that create the spray channel 302. In this embodiment, the nozzles 314 are arranged in two rows. However, in other embodiments, the nozzles 314 may be arranged in a single row or more than two rows.

[0063] A controller (e.g., jet device controller 122) communicating with printhead 104 includes a drive waveform generator (also called a pulse generator) configured to generate drive waveforms (e.g., trapezoidal waveforms) from the driver circuitry in printhead 104. The drive waveform is a series or sequence of jet pulses selectively applied to actuator 316 of jet channel 302. Figure 8 The jet pulse 800, representing the drive waveform of the printhead in the illustrative embodiment, is shown. Figure 8 The driving waveform is shown as a low-level active signal, but in other embodiments it can be a high-level active signal. The jet pulse 800 has a trapezoidal shape and can be characterized by the following parameters: fall time, rise time, pulse width, and jet amplitude. The jet pulse 800 transitions from a baseline (high) voltage 801 to a jet (low) voltage 802 along its leading edge 804. The potential difference between the baseline voltage 801 and the jet voltage 802 represents the amplitude of the jet pulse 800, which is the peak amplitude of the jet pulse 800. The jet pulse 800 then transitions from the jet (low) voltage 802 back to the baseline (high) voltage 801 along its trailing edge 805. These parameters of the jet pulse 800 can affect the jetting characteristics (e.g., droplet velocity and mass) of the droplets from the jet channel 302. For example, a target jet amplitude (i.e., jet voltage) with a desired velocity and mass is jetted from the jet channel 302 when the amplitude of the jet pulse 800 is equal to the target pulse width. Standard jet pulse 800 can be selected for different types of printheads to produce droplets with desired shape (e.g., spherical), size, speed, etc.

[0064] The following provides an example of using a jet pulse 800 to eject droplets from a jet channel 302, for example from... Figure 3-4The injection channel 302 is described. The injection pulse 800 is initially at a baseline voltage 801 and transitions from the baseline voltage 801 to the injection voltage 802. The leading edge 804 (i.e., the first slope) of the injection pulse 800 causes the actuator 316 to shift in a first direction, which expands the pressure chamber 312 and generates a negative pressure wave within it. The negative pressure wave propagates within the pressure chamber 312 and is reflected as a positive pressure wave by structural changes within the pressure chamber 312. The trailing edge 805 (i.e., the second slope) of the injection pulse 800 causes the actuator 316 to shift in the opposite direction, which reduces the pressure chamber 312 to its original size and generates another positive pressure wave. When the timing of the trailing edge 805 of the injection pulse 800 is appropriate, the positive pressure wave generated by the shift of the actuator 316 to reduce the size of the pressure chamber 312 combines with the reflected positive pressure wave to form a sufficiently large combined wave, causing droplets to be ejected from the nozzle 314 of the injection channel 302. Therefore, the positive pressure wave generated by the trailing edge 805 of the jet pulse 800 amplifies the positive pressure wave reflected within the pressure chamber 312 due to the leading edge 804 of the jet pulse 800. The geometry of the pressure chamber 312 and the jet pulse 800 are designed to generate a large positive pressure peak at the nozzle 314, driving the printing fluid through the nozzle 314.

[0065] Figure 9 A pressure wave 902 is shown in the pressure chamber 312 of the injection channel 302 in an illustrative embodiment. When the actuator 316 is displaced in response to the injection pulse 800, the pressure wave 902 will resonate or be absorbed at a characteristic frequency. This characteristic frequency is determined by the geometry of the pressure chamber 312 (and other structures of the injection channel 302) and the fluid properties associated with them, and is referred to as the resonant frequency or Helmholtz frequency of the injection channel 302.

[0066] Because multiple jet channels 302 are connected to or will be connected to a common manifold 418 in the printhead 104, pressure waves 902 can escape from the jet channels 302 and propagate along the manifold 418 in the nozzle row direction. If the manifold 418 vibrates at the same frequency as the jet channels 302, the manifold vibration can excite pressure waves escaping from the jet channels 302 within the manifold 418. Unfortunately, this can lead to variations in jet performance from channel to channel.

[0067] To solve this problem, the length of the manifold 418 in the printhead 104 is selected such that its resonant frequency is different from the resonant frequency of the jet channel 302. Figure 10 This is a cross-sectional view of the printhead 104 in the illustrative embodiment. Figure 10 The cross section shown is along Figure 7View arrow 10-10 in the figure. This cross-sectional view shows the manifold 418 of the printhead 104. In this embodiment, the manifold 418 includes a longitudinal portion 1002, which is generally disposed longitudinally within the printhead 104 along a row of jet channels 302. The longitudinal portion 1002 is at least partially formed by the manifold conduit 617 of the housing 230 (see view 1002). Figure 6 The manifold 418 also includes transverse portions 1003-1004, which are typically arranged transversely within the printhead 104 between the longitudinal portion 1002 and the open ends 1011-1012. Therefore, the length 1020 of the manifold 418 is defined as the length of the fluid path between the open ends 1011 and 1012. Along the length 1020, the manifold 418 is formed from one or more structural elements of the printhead 104 having the same or similar materials. For example, metals, metal alloys, etc., can be formed along the length 1020 between the open ends 1011-1012 such that the material properties are consistent along the length 1020. Furthermore, the volume of the manifold 418 can be consistent along the length 1020. In this embodiment, the length 1020 of the manifold 418 is chosen such that the resonant frequency of the manifold 418 is different from the resonant frequency of the jet channel 302.

[0068] Figure 11 This is a schematic diagram of a design tool 1100 for a printhead 104 in an illustrative embodiment. The design tool 1100 is a means or apparatus configured to assist in designing a printhead (e.g., printhead 104). More specifically, the design tool 1100 may be configured to determine one or more dimensions of the manifold 418 in the printhead 104, although it may also be configured to determine other design aspects of the printhead 104. The design tool 1100 includes a hardware platform comprising a processor 1110 and a memory 1112. The processor 1110 includes integrated hardware circuitry configured to execute instructions stored in the memory 1112. The memory 1112 is a non-transitory computer-readable storage medium for data, instructions, etc., and is accessible by the processor 1110. The design tool 1100 may further include a user interface 1114. The user interface 1114 is a hardware component for interacting with an end user. For example, the user interface 1114 may include a display, screen, touchscreen, etc. (e.g., a liquid crystal display (LCD), a light-emitting diode (LED) display, etc.). User interface 1114 may include a keyboard or keypad, a tracking device (e.g., a trackball or trackpad), a speaker, a microphone, etc. Design tool 1100 may include components not present in... Figure 11 The various other components are specifically shown in the diagram.

[0069] Figure 12 This is a flowchart illustrating a method 1200 for designing a printhead 104 in an illustrative embodiment. (Refer to...) Figure 11The design tool 1100 described herein is used to describe the steps of method 1200; however, those skilled in the art will understand that method 1200 can be performed by other systems, tools, or entities. Furthermore, the steps in the flowcharts described herein are not exhaustive and may include other steps not shown, and these steps may be performed in an alternative order.

[0070] For this embodiment, it is assumed that printhead 104 includes or will include manifold 418, and manifold 418 is fluidly coupled to the plurality of jet channels 302 as described above. Method 1200 includes determining the resonant frequency of the jet channels 302 of printhead 104 (step 1202). For example, design tool 1100 may perform tests on printhead 104 or a similar printhead (i.e., another printhead having jet channels of the same or similar dimensions), or may receive test data with respect to printhead 104 or a similar printhead, to determine the resonant frequency of jet channels 302. Design tool 1100 may perform simulations on printhead 104 or a similar printhead, or may receive simulation data with respect to printhead 104 or a similar printhead, to determine the resonant frequency of jet channels 302. Design tool 1100 may determine the resonant frequency of jet channels 302 in other ways.

[0071] Manifold 418 has or will have a natural vibration frequency determined by the physical parameters of manifold 418. One of the parameters defining the natural vibration frequency of manifold 418 is the length 1020 of manifold 418. Method 1200 includes selecting, determining, or calculating a target length of manifold 418 such that the resonant frequency of manifold 418 differs from the resonant frequency of injection channel 302 by a threshold amount (step 1204). In other words, a target length is selected such that the resonant frequency of manifold 418 is not the same as the resonant frequency (and any harmonics) of injection channel 302. As mentioned above, if the resonant frequency of manifold 418 is the same as the resonant frequency of injection channel 302, the vibration of manifold 418 can excite pressure waves escaping from injection channel 302. Therefore, it is necessary to determine the length of manifold 418 that vibrates naturally at a resonant frequency different from the resonant frequency of injection channel 302. Design tool 1100 can display or otherwise provide the target length to the user through user interface 1114, transmit the target length to a remote system over a network, or perform other functions when the target length is selected.

[0072] In one embodiment, design tool 1100 can determine multiple expected lengths of manifold 418, where each expected length results in a resonant frequency different from the resonant frequency of jet channel 302. Design tool 1100 can then select a target length of manifold 418 from one of the expected lengths. For example, design tool 1100 can select (e.g., automatically) the target length based on other dimensions of printhead 104. In another example, design tool 1100 can display or otherwise provide the expected length to a user via user interface 1114 and receive the target length selected by the user.

[0073] Method 1200 may further include configuring the length 1020 of the manifold 418 in the printhead 104 to a target length (step 1206). For example, in Figure 10 In this process, the length 1020 of manifold 418 from opening end 1011 to opening end 1012 will be set as the target length. In one embodiment, design tool 1100 may display or otherwise provide the target length to a user via user interface 1114, transmit the target length to a remote system via a network (optional step 1209), or perform other functions when the target length is selected. In another embodiment, printhead 104 may be in the design phase, pre-manufacturing phase, or manufacturing phase of method 1200. Design tool 1100 or another system / entity may control, regulate, set, or instruct one or more manufacturing processes to manufacture manifold 418 to the target length (optional step 1210). For example, manifold conduits 616-617 in housing 230 may be cut or formed based on the target length (see [link to design tool]). Figure 6 The height of housing 230 can be selected based on the target length, the length of the hose connectors for I / O ports 213-214 can be selected based on the target length, and so on.

[0074] In another embodiment, printhead 104 may include a pre-manufactured head, commonly referred to as an assembled printhead. In the assembled printhead, the length 1020 of manifold 418 may be adjusted to a target length (optional step 1212). In one embodiment, one or more extenders or similar structural elements may be used to adjust the length 1020 of manifold 418 to the target length. Figure 13 This is a cross-sectional view of a printhead 104 with an extender 1310 in an illustrative embodiment. In this embodiment, the extender 1310 may be attached, secured, or added to at least one open end 1011-1012 of the manifold 418 to extend the manifold 418 to a target length. Figure 12(Optional step 1214). Extender 1310 can be connected to I / O ports 213-214 of printhead 104, where printing fluid enters or exits printhead 104. Extender 1310 is a hollow structural component with a fluid path aligned with manifold 418. Extender 1310 can be made of the same or similar type of material as housing 230 and / or I / O ports 213-214, for example, having similar or equal stiffness. Extender 1310 has an extension length 1312 for moving the open ends 1011-1012 of manifold 418 and changing the length 1020 of manifold 418. Therefore, the extension length 1312 of extender 1310 can be determined or selected (e.g., from a set of standard extender sizes) such that the manifold length of existing printhead 104 can be changed to a target length. Extender 1310 can be applied to one or both open ends 1011-1012. If the extension 1310 is applied to the two open ends 1011-1012, the extension 1310 can have different extension lengths 1312. If the I / O ports 213-214 are connected to the container 124 via hoses or the like, then the extension 1310 can be connected to the hose fittings of the I / O ports 213-214. Furthermore, the outer surface of the extension 1310 may include hose fittings or hose barbs, allowing the hose to be directly attached to the extension 1310.

[0075] Method 1200 can be repeated for any number of manifolds 418 to determine the target length of each manifold 418.

[0076] like Figure 10 The manifold 418 shown is a closed fluid passage with open ends 1011-1012. Therefore, in one embodiment, the design tool 1100 can determine the target length of the manifold 418 by modeling it as an open-end air column. The resonant frequency of the open-end air column depends on the speed of sound in the air, as well as the length and geometry of the air column. Longitudinal pressure waves are reflected from the open ends, forming a standing wave pattern. The lowest resonant frequency of the air column is called the fundamental frequency (or first harmonic). The air column also generates harmonics of the fundamental frequency, which are integer multiples of the fundamental frequency.

[0077] The fundamental frequency (f1) of the open air column can be determined based on equation [1]:

[0078]

[0079] in

[0080] V sound Here, L is the speed of sound in air, and L is the length of the air column. The harmonics of the air column are integer multiples of the fundamental frequency. For example, the first harmonic (N=2) is:

[0081] 2*f1

[0082] The second harmonic (N=3) is

[0083] 3*f1

[0084] Using equation [1], design tool 1100 can determine the resonant frequency of manifold 418 of different lengths and select a target length that produces a resonant frequency different from that of injection channel 302.

[0085] The above equation can be used to directly solve for the target length of manifold 418 modeled based on the open-end air column. For example, equation [1] can be rearranged to solve for...

[0086] L

[0087] As shown in equation [2]:

[0088]

[0089] If the resonant frequency of the jet channel 302 is used for the frequency (f) in equation [2] and the velocity of sound in the printing fluid is used

[0090] V sound

[0091] Equation [2] will then generate the length (L) of manifold 418, which has a fundamental frequency that matches the resonant frequency of injection channel 302. However, the goal is to select a target length of manifold 418 with a resonant frequency different from that of injection channel 302. Therefore, an adjustment percentage can be added to Equation [2] to avoid or exclude lengths with a resonant frequency that matches the resonant frequency of injection channel 302. The adjustment percentage can depend on the desired threshold amount of difference between the resonant frequency of manifold 418 and the resonant frequency of injection channel 302. For example, the adjustment percentage can be selected from the range of 0.2-0.8 (e.g., 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8), or another desired percentage. Therefore, the target length of manifold 418 can be calculated based on Equation [3]:

[0092]

[0093] in

[0094] N is an integer representing the harmonics.

[0095] V sound It is the speed of sound in the printing fluid (e.g., 1200-1500 mps).

[0096] % adjis the adjustment percentage, and f is the resonant frequency (i.e., fundamental frequency) of the injection channel 302. When the adjustment percentage is set to “0.5”, equation [3] can generate the “optimal” target length of the manifold 418. The optimal target length generates the resonant frequency of the manifold such that the resonant frequency of the injection channel 302 is in the middle of the resonant frequency of the manifold. Therefore, the node of the resonant frequency of the manifold 418 is as far away as possible from the node of the resonant frequency of the injection channel 302.

[0097] In the above embodiment, manifold 418 includes a fluid path having two open ends 1011-1012. In another embodiment, manifold 418 may include one open end and one closed end. Figure 14 This is a schematic diagram of the printhead 104 in an illustrative embodiment. The ejection channel 302 of the printhead 104 is again illustrated as a nozzle 314 in two nozzle rows 501-502. The printhead 104 (i.e., the head member 202) includes a plurality of manifolds 418. One of the manifolds 418 includes a single I / O port 211 and is fluidly coupled to the ejection channel 302 in the nozzle row 501. The other of the manifolds 418 includes a single I / O port 212 and is fluidly coupled to the ejection channel 302 in the nozzle row 502.

[0098] Figure 15 This is a cross-sectional view of the printhead 104 in an illustrative embodiment, showing the manifold 418. In this embodiment, the manifold 418 includes a longitudinal portion 1002, which is generally disposed longitudinally within the printhead 104 along a row of jet channels 302. The manifold 418 also includes a transverse portion 1003, which is generally disposed transversely within the printhead 104 between the longitudinal portion 1002 and the open end 1011. Therefore, the length 1020 of the manifold 418 is defined as the length of the fluid path between the open end 1011 and the closed end 1504. In the above embodiment, the length 1020 of the manifold 418 is selected such that the resonant frequency of the manifold 418 is different from the resonant frequency of the jet channels 302.

[0099] In one embodiment, the design tool 1100 can be used by... Figure 15 The manifold 418 is modeled as a closed-end air column to determine the target length. The resonant frequency of the closed-end air column depends on the speed of sound in the air, as well as the length and geometry of the air column. The closed-end air column will generate resonant standing waves with the fundamental frequency and odd harmonics.

[0100] The fundamental frequency (f1) of the closed-end air column can be determined based on equation [4]:

[0101]

[0102] in

[0103] V soundLet L be the speed of sound and L be the length of the air column. The harmonics of the air column are odd integer multiples of the fundamental frequency.

[0104] like Figure 15 The target length of the manifold 418 shown can be calculated based on equation [5]:

[0105]

[0106] in

[0107] N is an odd integer representing the harmonics.

[0108] V sound It is the speed of sound in the printing fluid.

[0109] % adj It's about adjusting the percentage, and

[0110] f is the resonant frequency of the injection channel 302.

[0111] The above system and method can be used to select the target length for any type of manifold in the printhead. Figure 5 and 14 The manifold 418 shown can be considered as a supply manifold that delivers printing fluid to the jet channel 302. However, a flow-through printhead is also considered herein to include one or more supply manifolds and one or more return manifolds. A flow-through printhead is described in U.S. Patent No. 9,272,514, which is incorporated herein by reference as if it were entirely included. The systems and methods described above can be used to select target lengths for both the return manifolds and the supply manifolds in a printhead.

[0112] The embodiments disclosed herein may take the form of software, hardware, firmware, or various combinations thereof. In one particular embodiment, the software is used to instruct the processing system of the design tool 1100 to perform the various operations disclosed herein. Figure 16 A processing system 1600, operable in an illustrative embodiment, is shown that can execute a computer-readable medium embodying program instructions to perform a desired function. The processing system 1600 can be used to perform the above-described operations by executing programming instructions tangibly contained on a computer-readable storage medium 1612. In this respect, embodiments may take the form of a computer program accessible via the computer-readable medium 1612, which provides program code for use by a computer or any other instruction execution system. For the purposes of this description, the computer-readable storage medium 1612 can be anything capable of containing or storing a program for use by a computer.

[0113] Computer-readable storage medium 1612 can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor device. Examples of computer-readable storage media 1612 include solid-state storage, magnetic tape, removable computer disk, random access memory (RAM), read-only memory (ROM), hard disk, and optical disc. Examples of current optical discs include read-only memory optical disc (CD-ROM), read / write optical disc (CD-R / W), and DVD.

[0114] A processing system 1600 suitable for storing and / or executing program code includes at least one processor 1602 coupled to a program and data memory 804 via a system bus 1650. The program and data memory 1604 may include local memory, mass storage, and cache memory used during the actual execution of the program code, providing temporary storage for at least some program code and / or data to reduce the number of times code and / or data are retrieved from mass storage during execution.

[0115] Input / output or I / O devices 1606 (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled directly or via an intermediate I / O controller. Network adapter interface 1608 can also be integrated with the system to enable processing system 1600 to be coupled to other data processing systems or storage devices via an intermediate private or public network. Modems, cable modems, IBM Channel accessories, SCSI, Fibre Channel, and Ethernet cards are just a few of the currently available network or host interface adapter types. Display device interface 1610 can be integrated with the system to connect to one or more display devices, such as printing systems and screens for displaying data generated by processor 1602.

[0116] Although specific embodiments have been described herein, the scope of the invention is not limited to these specific embodiments. The scope of the invention is defined by the following claims and any equivalents thereof.

[0117] This patent application is based on and claims priority to U.S. Patent Application No. 17 / 194869, filed March 8, 2021. The contents of U.S. Patent Application No. 17 / 194869 are incorporated herein by reference in their entirety.

Claims

1. A method for designing a printhead, characterized in that, include: Determine the resonant frequency of the printhead's ejection channel; and Select the target length of the manifold that is fluidly coupled to the injection channel, such that the resonant frequency of the manifold differs from the resonant frequency of the injection channel by a threshold amount. The manifold includes a fluid path between a first open end and a second open end; as well as Selecting the target length of the manifold includes modeling the manifold as an open-end air column; Selecting the target length of the manifold includes calculating the target length based on the following formula: in It is the harmonic number. It is an adjustment percentage within the range of 0.2-0.

8. It is the speed of sound in the printing fluid, and It is the resonant frequency of the injection channel; or The manifold includes a fluid path between an open end and a closed end; as well as Selecting the target length of the manifold includes modeling the manifold as a closed-end air column; Selecting the target length of the manifold includes calculating the target length based on the following formula: in It is an odd harmonic number. It is an adjustment percentage within the range of 0.2-0.

8. It is the speed of sound in the printing fluid, and It is the resonant frequency of the injection channel.

2. The method according to claim 1, characterized in that, Further includes: The target length of the manifold is provided to the user via a user interface.

3. The method according to claim 1, characterized in that, Further includes: Control at least one manufacturing process to manufacture the manifold to the target length.

4. The method according to claim 1, characterized in that... : The printhead includes an assembled printhead; and The method further includes adjusting the length of the manifold of the assembled printhead to the target length.

5. The method according to claim 4, characterized in that... : Adjusting the length of the manifold of the assembled printhead includes attaching an extender to at least one open end of the manifold to extend the manifold to the target length.

6. A design tool for printheads, characterized in that, include: At least one processor and memory; The at least one processor enables the design tool to: Determine the resonant frequency of the ejection channel of the printhead; as well as Select the target length of the manifold that is fluidly coupled to the injection channel, such that the resonant frequency of the manifold differs from the resonant frequency of the injection channel by a threshold amount. The manifold includes a fluid path between a first open end and a second open end; as well as The at least one processor enables the design tool to select the target length of the manifold by modeling the manifold as an open-end air column; The at least one processor enables the design tool to calculate the target length based on the following formula: in It is the harmonic number. It is an adjustment percentage within the range of 0.2-0.

8. It is the speed of sound in the printing fluid, and It is the resonant frequency of the injection channel; or The manifold includes a fluid path between an open end and a closed end; as well as The at least one processor enables the design tool to select the target length of the manifold by modeling the manifold as a closed-end air column; The at least one processor enables the design tool to calculate the target length based on the following formula: in It is an odd harmonic number. It is an adjustment percentage within the range of 0.2-0.

8. It is the speed of sound in the printing fluid, and It is the resonant frequency of the injection channel.

7. The design tool according to claim 6, characterized in that... : The at least one processor enables the design tool to control at least one manufacturing process to manufacture the manifold to the target length.

8. The design tool according to claim 6, characterized in that, Further includes: A user interface configured to provide the user with the target length of the manifold.

9. A printhead, characterized in that, include: Multiple injection channels; and The fluid is coupled to the manifold of the injection channel; The length of the manifold is selected to produce a resonant frequency that differs from the resonant frequency of the injection channel by a threshold amount. The manifold includes a fluid path between a first open end and a second open end; and The length of the manifold is selected based on the following formula: in It is the harmonic number. It is an adjustment percentage within the range of 0.2-0.

8. It is the speed of sound in the printing fluid, and It is the resonant frequency of the injection channel; or The manifold includes a fluid path between an open end and a closed end; and The length of the manifold is selected based on the following formula: in It is an odd harmonic number. It is an adjustment percentage within the range of 0.2-0.

8. It is the speed of sound in the printing fluid, and It is the resonant frequency of the injection channel.

10. A spraying device, characterized in that, include: At least one printhead according to claim 9.

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