Printing head, printing assembly and printing equipment

Abstract

The invention provides a printing head, a printing assembly and printing equipment. The printing head comprises a liquid supply main flow channel and a liquid supply main flow channel, the spraying units comprise heaters and spraying holes, the spraying holes are used for receiving to-be-sprayed liquid from the liquid supply main flow channel, the heaters are used for heating the to-be-sprayed liquid under the action of pulse signals and generating bubbles, and the pulse frequency of the pulse signals is f0; the multiple spraying units comprise the first spraying unit and the second spraying unit, the distance between the spraying hole of the first spraying unit and the liquid supply main flow channel is different from the distance between the spraying hole of the second spraying unit and the liquid supply main flow channel, the filling frequency of the first spraying unit is f1, the filling frequency of the second spraying unit is f2, f1 / f2 is larger than or equal to 0.9 and smaller than or equal to 1.1, and f2 / f2 is larger than or equal to 0.9 and smaller than or equal to 1.1. The problem that the overall printing effect of the printing head is not ideal due to the fact that the filling frequency of part of the injection units is not matched with the pulse frequency can be solved.

Description

Technical Field

[0001] The present application relates to the technical field of fluid jet printing, and in particular to a print head, a printing assembly and a printing device. Background Art

[0002] Inkjet printers are common office equipment, providing great convenience for modern office work. As the core component of inkjet printers, the characteristics of inkjet print heads are usually closely related to the printing quality. Thermal drive print heads are a common type of inkjet print heads. Thermal drive print heads (referred to as print heads) are usually composed of multiple ejection units, each of which includes a heater, a chamber, a liquid inlet channel, a nozzle and other structures.

[0003] In the current technology, based on the specific requirements of the injection algorithm, the distances between the nozzles of different injection units and the main ink supply channel may be different, which will lead to inconsistent filling frequencies (i.e., liquid replenishment duration) of different injection units, making the filling frequencies of at least some injection units in the print head mismatched with the pulse frequency of the pulse signal acting on the heater. When the filling frequency of the injection unit does not match the pulse frequency, the printing effect of the injection unit will be poor, which will cause the overall printing effect of the print head to be unsatisfactory. Summary of the invention

[0004] The embodiments of the present application provide a print head, a printing assembly and a printing device, which can solve the problem of unsatisfactory overall printing effect of the print head caused by the mismatch between the filling frequency and the pulse frequency of some injection units.

[0005] In a first aspect, a print head is provided, comprising: a liquid supply main channel; a plurality of injection units, the injection units comprising a heater and a nozzle, the nozzle being used to receive liquid to be injected from the liquid supply main channel, the heater being used to heat the liquid to be injected and generate bubbles under the action of a pulse signal, the pulse frequency of the pulse signal being f0; the plurality of injection units comprising a first injection unit and a second injection unit, the distances between the nozzle of the first injection unit and the nozzle of the second injection unit and the liquid supply main channel being different, the filling frequency of the first injection unit being f1, the filling frequency of the second injection unit being f2, 0.9≤f1 / f0≤1.1, 0.9≤f2 / f0≤1.1.

[0006] According to the print head provided in the embodiment of the present application, by performing structural differentiation design on different injection units, that is, different injection units can adopt different design schemes, so that even if the distances between the nozzles and the liquid supply main channel of two injection units (for example, the first injection unit and the second injection unit) are different, the filling frequencies of the two injection units can simultaneously match the pulse frequency of the pulse signal applied to the heater (for example, the same or similar), that is, a larger number of injection units including the first injection unit and the second injection unit can simultaneously match the pulse frequency, thereby reducing or even avoiding the "empty spray" phenomenon of the injection unit, and the injection ignition timing of a larger number (for example, all the number) of injection units can coincide with the downward time of the secondary oscillation, and the liquid flow direction in the nozzle will be consistent with the direction of the bubble, ensuring that a larger number of injection units can obtain better printing effects, thereby improving the overall printing effect of the print head.

[0007] In a possible implementation manner, a filling frequency of any one of the plurality of injection units is fn, and 0.9≤fn / f0≤1.1.

[0008] That is to say, by setting the structural details of each injection unit, the filling frequency of all the injection units of the print head is matched with the pulse frequency of the pulse signal, and the relationship of 0.9≤fn / f0≤1.1 is satisfied. In this way, all the injection units will not have the "empty spray" phenomenon, and the injection ignition timing of all the injection units can coincide with the downward time of the secondary oscillation, and the liquid flow direction in the nozzle will be consistent with the direction of the bubble, thereby improving the overall printing effect of the print head to a greater extent.

[0009] In one possible implementation, 0.95≤fn / f0≤1.05.

[0010] That is to say, the filling frequency fn of the ejection unit is closer to the pulse frequency f0 of the pulse signal, that is, the matching degree between the filling frequency and the pulse frequency is higher, thereby further improving the ejection effect of each ejection unit, and further improving the overall printing effect of the print head.

[0011] In a possible implementation, the first spray unit and the second spray unit belong to a first spray unit group, and the distances between the spray holes of the plurality of spray units in the first spray unit group and the liquid supply main channel decrease sequentially.

[0012] In a possible implementation, the spray unit further includes a chamber and a liquid supply branch channel, and the liquid supply main channel sequentially supplies the liquid to be sprayed to the spray hole through the liquid supply branch channel and the chamber.

[0013] In a possible implementation manner, the structure of at least one of the liquid supply branch channel, the chamber, or the spray hole of the first spray unit and the second spray unit is different.

[0014] Optionally, the structures of the chambers of the first spray unit and the second spray unit are different, for example, the two chambers are different in size or shape, or in different relative positions to the spray holes.

[0015] Optionally, the structures of the branch liquid supply channels of the first spray unit and the second spray unit are different, for example, the diameters (widths) of the two branch liquid supply channels are different.

[0016] Optionally, the structures of the spray holes of the first spray unit and the second spray unit are different, for example, the sizes or shapes of the two spray holes are different.

[0017] In a possible implementation, a first blocking member is disposed in the liquid supply branch channel of the first spray unit and / or the second spray unit.

[0018] Optionally, the first blocking member may be a blocking block. The shape of the first blocking member may be any regular or irregular shape such as a triangle, a rectangle, a trapezoid, a circle, a diamond, a racetrack, etc.

[0019] Optionally, a plurality of second blocking members are arranged at intervals in the main liquid supply channel, and the second blocking members may be circular blocking blocks.

[0020] In a possible implementation, the structures of the first blocking member disposed in the liquid supply branch channel of the first spray unit and the second spray unit are different.

[0021] In a possible implementation, the branch liquid supply channel of the first injection unit is in a Y-shaped structure as a whole, and two branches of the Y-shaped structure are connected to the chamber.

[0022] By setting the liquid supply branch channel to a y-shaped structure, the liquid supply branch channel can have a non-return characteristic, reducing the ink backflow and significantly reducing the liquid replenishment time, thereby enabling better regulation and control of the filling frequency of the injection unit.

[0023] In a possible implementation manner, at least one branch in the Y-shaped structure is a J-shaped hook structure.

[0024] Through the above arrangement, the ink returning in the two branches can be offset as much as possible. At this time, the kinetic energy of the ink returning in the two branches can be offset more fully, thereby ensuring that the liquid supply branch channel has a sufficiently reliable anti-return characteristic.

[0025] In one possible implementation, the print head includes a base layer, a chamber layer, and a nozzle layer which are stacked in sequence, the heater is located on the inner surface of the base layer to heat the liquid to be sprayed in the chamber, the chamber, the liquid supply branch channel, and the liquid supply main channel are formed in the chamber layer, and the nozzle is formed in the nozzle layer.

[0026] In a second aspect, a printing assembly is provided, comprising a print head provided by any possible implementation of the first aspect, and a liquid storage device for providing the print head with liquid to be ejected.

[0027] In a possible implementation, the liquid storage device includes an ink cartridge, and the print head is disposed on an outer wall of the ink cartridge.

[0028] In a third aspect, a printing device is provided, comprising a print head provided by any possible implementation of the first aspect, or a printing component provided by any possible implementation of the second aspect, and a controller for providing a pulse signal to the print head.

[0029] In a possible implementation, the printing device is an inkjet printer.

[0030] Optionally, the printing device may be, for example, a two-dimensional (2D) printer (e.g., an inkjet printer) or a three-dimensional (3D) printer, and the printing device may be, for example, a printing device in a home or office, and may be used to realize functions such as black and white paper printing, color paper printing, paint spraying, digital spray painting, digital photo printing, digital printing, digital color proofing, image and artwork reproduction, advertising spray painting or digital printing. The printing device may also be a printing device in industrial applications, for example, the printing device may be a printing device in the fields of display film encapsulation, flexible printed electronics, color filter production, liquid crystal display production, large flat flexible flat panel device production, circuit board production, biomedical field, biological tissue engineering, barcode printing, and food production.

[0031] The printing device includes a housing and a printing assembly arranged in the housing, and the printing assembly is used as a core component of the printing device to realize the printing function. The printing assembly further includes a print head and a liquid storage device (such as an ink cartridge) for providing the print head with a liquid to be sprayed. Here, the liquid to be sprayed is sprayed on the substrate by the print head, and the specific types of the liquid to be sprayed and the substrate are not limited in this application. In combination with the specific type or use of the printing device listed above, the liquid to be sprayed can be any fluid such as ink (such as black or any color ink), paint, edible fluid, industrial production fluid, biological fluid or medicament. The substrate can be, for example, paper, wall, billboard, circuit board (such as hard board or soft board), display panel, optical sheet, etc., any object with printing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the injection unit.

[0033] Figure 2 It is a schematic diagram of the injection process of the injection unit.

[0034] Figure 3 It is a structural schematic diagram of the injection unit group in the current technology.

[0035] Figure 4 It is a schematic diagram of the oscillation law of single pulse jet liquid.

[0036] Figure 5 This is a schematic diagram of frequency-matched multi-pulse continuous jet resonance and a printing effect diagram.

[0037] Figure 6 This is a schematic diagram of multi-pulse continuous jet oscillation with mismatched frequencies and a printing effect diagram.

[0038] Figure 7 It is a schematic diagram of the structure of the printing device provided in an embodiment of the present application.

[0039] Figure 8 It is a schematic diagram of the installation structure of the print head provided in an embodiment of the present application.

[0040] Fig. 9 It is a cross-sectional schematic diagram of the print head provided in the embodiment of the present application.

[0041] Fig.10 It is a schematic diagram of the structural decomposition of the print head provided in an embodiment of the present application.

[0042] Fig.11 It is a structural schematic diagram of an example of the first injection unit group provided in an embodiment of the present application.

[0043] Fig.12It is a structural schematic diagram of another example of the first injection unit group provided in an embodiment of the present application.

[0044] Fig.13 It is a structural schematic diagram of another example of the first injection unit group provided in an embodiment of the present application.

[0045] Fig.14 It is a structural schematic diagram of another example of the first injection unit group provided in an embodiment of the present application.

[0046] Fig.15 It is a structural schematic diagram of another example of the first injection unit group provided in an embodiment of the present application.

[0047] Reference numerals:

[0048] 1. Chamber shell; 2. Chamber; 3. Nozzle; 4. Heater; 5. Liquid inlet channel; 6. Silicon substrate; 7. Protective layer; 9. Bubble; 10. Ink droplet;

[0049] 21. First injection unit; 22. Second injection unit; 23. Third injection unit; 24. Main flow channel; 25. Stop block;

[0050] 100, print head; 110, base layer; 111, heater; 112, liquid inlet hole; 120, chamber layer; 121, chamber; 122, liquid supply main channel; 123, liquid supply branch channel; 124, first blocking member; 125, second blocking member; 130, nozzle layer; 131, nozzle; 141, first injection unit; 142, second injection unit; 143, third injection unit;

[0051] 200, ink cartridge;

[0052] 300, ink bottle;

[0053] 400, ink supply tube;

[0054] 500, housing;

[0055] 600, paper;

[0056] 700. Controller. DETAILED DESCRIPTION

[0057] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0058] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0059] In the description of the present application, it should be understood that the terms "upper", "lower", "side", "front", "rear", etc. indicate orientations or positional relationships based on the installation, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0060] It should also be noted that, in the embodiments of the present application, the same figure mark is used to represent the same component or the same part. For the same parts in the embodiments of the present application, the figure may only mark one of the parts or components as an example. It should be understood that the figure mark also applies to other identical parts or components.

[0061] Inkjet printers are common office equipment that provide great convenience for modern office work. The printing method of inkjet printers is usually that the ink source is provided by an ink container such as an ink cartridge, and the ink is transported to the print head through the corresponding ink supply pipe. Driven by the print signal, the ink is ejected from the nozzle set on the print head to the paper or other substrates to complete the recording of text or graphics. As the core component of the inkjet printer, the working characteristics of the print head are usually closely related to the printing quality. The print head is usually attached to the bottom surface of the ink cartridge to obtain the ink stored in the ink cartridge and realize the printing function. According to the ink droplet ejection mechanism, the print head can be divided into two types: piezoelectric driving type and thermal driving type.

[0062] The piezoelectric drive type print head uses the deformation of piezoelectric materials to eject ink. The piezoelectric drive type print head has one or more piezoelectric crystals in the ink chamber connected to the nozzle. The piezoelectric crystal is controlled by the print signal modulated by the data to produce contraction or expansion deformation, squeezing the ink in the nozzle to form fine droplets after being ejected from the nozzle, splashing onto the substrate such as a page of paper, forming a recording point.

[0063] Thermally driven print heads use heat sources to generate bubbles in the ink and eject ink droplets when the bubbles expand. Thermally driven print heads are equipped with a heater in the ink chamber connected to the nozzle. The data-modulated electrical pulse signal is transmitted to the heater, which quickly heats up, causing the ink in the chamber to vaporize rapidly and form bubbles. The pressure generated by the expansion of the bubbles causes the ink to form tiny droplets after being ejected from the nozzle, splashing onto paper and other substrates. After the electrical pulse disappears, the ink vapor condenses and forms a negative pressure in the chamber. The negative pressure guides the ink in the ink supply pipe to quickly flow into the ink chamber to achieve timely replenishment of the ink. At this time, the ink in the nozzle is once again kept flush with the outer port of the nozzle by its own surface tension.

[0064] The present application mainly relates to the structural improvement of a thermal drive type print head. A thermal drive type print head is usually composed of a plurality of ejection units. Figure 1 is a schematic diagram of the structure of the injection unit, where: Figure 1 Part (a) is a horizontal cross-section of the injection unit. Figure 1 Part (b) in the figure is a vertical cross-sectional view of the injection unit. Figure 1 As shown, the injection unit includes a heater 4, a chamber 2, a liquid inlet channel 5, a spray hole 3 and other structures.

[0065] Specifically, the chamber shell 1 is sealed and covered on the silicon substrate 6, and together with the silicon substrate 6, defines a chamber 2 for storing ink, and defines a liquid inlet channel 5 for supplying ink to the chamber 2. The chamber 2 is also connected to the nozzle 3 provided on the chamber shell 1. The heater 4 (such as a heating resistor) is arranged on the inner surface of the silicon substrate 6, and is used to heat the ink in the chamber 2, and spray the ink to the external paper or other printing material through the nozzle 3. A protective layer 7 is arranged on the surface of the heater 4 facing the nozzle 3, and the protective layer 7 is used to protect the heater 4, so as to improve the durability and reliability of the heater 4.

[0066] Figure 2 It is a schematic diagram of the injection process of the injection unit. Figure 2 As shown in part (a) of FIG. 1 , in the initial state, the ink fills the chamber 2 and the nozzle hole 3 through the liquid inlet channel 5, and the ink in the nozzle hole 3 maintains a state of being flush with the outer end of the nozzle hole 3 by its own surface tension, and the heater 4 does not work at this time. Figure 2 As shown in part (b) of FIG. 1 , at a certain moment, the host controller sends a pulse command (signal) to the heater 4, and the heater 4 generates an instantaneous high temperature (for example, more than 300°C), vaporizing the ink close to the surface of the heater 4, generating bubbles 9 that exert pressure on the ink in the chamber 2 and the nozzle 3, so that the ink in the nozzle 3 is ejected from the print head to the paper in the form of ink droplets 10 to achieve the printing effect. Figure 2As shown in part (c), when the heater 4 stops heating, the bubbles collapse and negative pressure is formed in the chamber 2. The negative pressure guides the ink in the liquid inlet channel 5 to be refilled and replenished, waiting for the next injection instruction.

[0067] The spraying effect of the spray unit (such as droplet volume, initial velocity, etc.) is strongly correlated with multiple factors such as the operating frequency of the heater (i.e., pulse frequency), chamber shape, nozzle shape, and flow channel structure. Any slight adjustment of the above factors may significantly change the fluid mechanics inherent filling frequency of the spray unit, causing it to not match the operating frequency of the heater, thereby causing problems such as reduced droplet volume and decreased initial velocity, resulting in poor printing effects.

[0068] The print head is usually composed of a large number of ejection units, which can be divided into a plurality of ejection unit groups. Each ejection unit group usually includes a plurality of (eg, 3 or 4) ejection units. Figure 3 It is a schematic diagram of the structure of the injection unit group in the current technology. Figure 3 As shown, the injection unit group includes a first injection unit 21, a second injection unit 22 and a third injection unit 23, a total of three injection units, and there are obvious height differences between the three injection units, and the heights decrease proportionally from left to right. The height difference is required by the injection algorithm.

[0069] Specifically, Figure 3 As shown, the three injection units each include a chamber 2, a nozzle 3, and a liquid inlet channel 5 connecting the chamber 2 and the main channel 24. A plurality of blocking blocks 25 are arranged at intervals in the main channel 24, and the blocking blocks 25 are used to slow down the flow speed of the ink. The ink in the main channel 24 enters the corresponding chamber 2 and the nozzle 3 through the liquid inlet channel 5.

[0070] The three chambers 2 corresponding to the above three injection units have the same structure (for example, the shape and size are the same), and the corresponding three nozzle holes 3 also have the same structure. Considering the mobility of the paper during printing, in order to improve the printing effect, the distances between the three nozzle holes 3 and the main channel 24 are different, that is, from left to right, the nozzle holes 3 gradually approach the main channel 24, and the distance between the nozzle holes 3 and the main channel 24 decreases proportionally in turn. The above reasons lead to different lengths of the three liquid inlet channels 5 corresponding to the three injection units, that is, the heights of the three injection units are different (the height gradually decreases from left to right).

[0071] That is to say, for these three injection units, the distance between the spray hole 3 and the main channel 24 of the first injection unit 21 is the largest, the liquid inlet channel 5 of the first injection unit 21 is the longest, and the first injection unit 21 has the highest height; the distance between the spray hole 3 and the main channel 24 of the third injection unit 23 is the smallest, the liquid inlet channel 5 of the third injection unit 23 is the shortest, and the third injection unit 23 has the lowest height; the second injection unit 22 is between the first injection unit 21 and the third injection unit 23.

[0072] Since the distances between the spray hole 3 and the main channel 24 are different, the multiple spray units in the spray unit group have different heights (that is, the lengths of the liquid inlet channels 5 are different), which further leads to the inconsistency of the inherent fluid dynamics filling frequencies (that is, the liquid replenishment duration or liquid replenishment cycle) of each spray unit. Figure 3 The filling frequencies of the three injection units from left to right are 20.5KHz, 16.5KHz and 17.9KHz respectively, so that the pulse frequency of the pulse signal applied to the heater by the control system cannot match the filling frequencies of these three units at the same time.

[0073] In the case of frequency mismatch, "empty spray" phenomenon will occur, that is, the ink in the chamber has not been filled yet, but it has been ignited and sprayed, thereby disrupting the liquid oscillation in the nozzle. Figure 4 This is a schematic diagram of the oscillation law of a single pulse jet liquid. Figure 4 As shown in the figure, after the injection is completed, the liquid surface in the nozzle hole will undergo a periodic "contraction → overflow" oscillation, and its oscillation amplitude will gradually decrease until the kinetic energy of the liquid is completely consumed by friction. Usually, the energy of the second oscillation cannot be ignored, and the energy of the third and subsequent oscillations is relatively small.

[0074] Figure 5 This is a schematic diagram of frequency-matched multi-pulse continuous jet resonance and a printing effect diagram. Figure 5 As shown in part (a) of the diagram, if the filling frequency of the ejection unit matches the pulse frequency, the ejection ignition timing (i.e., the timing when the heater is powered on) will be synchronized with the secondary oscillation down time, and at this time (i.e., time t1 in the diagram), the ink in the nozzle is just filled, and the liquid flow direction (i.e., the direction away from the heater) is consistent with the direction of the bubble, so resonance will occur, and the ejected ink droplets will have a large volume, few satellite points, and accurate direction. Figure 5 As shown in part (b) of the figure, the final printed font is clear and has low line roughness.

[0075] Figure 6 This is a schematic diagram of multi-pulse continuous jet oscillation with mismatched frequencies and a printing effect diagram. Figure 6As shown in part (a) of the figure, if the filling frequency of the ejection unit does not match the pulse frequency, the ejection ignition timing will coincide with the secondary oscillation up-time. At this time, the ink in the nozzle hole has not been filled, and the liquid flow direction (i.e., the direction close to the heater) is opposite to the direction of the bubble. Therefore, the liquid flow is disturbed by the bubble, and the ejected ink droplets will carry multiple stray satellite ink droplets. The landing point on the paper surface is uncontrollable. At the same time, the volume of the ejected ink droplets will gradually decrease (after decreasing to a constant value and then stabilizing), which will eventually cause the printed font to be very blurred, as shown in Figure 1. Figure 6 In this case, the first printed drawing is relatively clear, and it gradually becomes blurred from the second one until it stabilizes.

[0076] Based on the above analysis, if the filling frequency of the jet unit matches the pulse frequency acting on the heater, the jet unit will not have the "empty spray" phenomenon, and the liquid flow direction in the nozzle hole is consistent with the direction of the bubble, so resonance will occur. At this time, the jet unit has a better jet (print) effect, and the final printed font is clear. If the filling frequency of the jet unit does not match the pulse frequency acting on the heater, the jet unit will have the "empty spray" phenomenon, and the liquid flow direction in the nozzle hole is opposite to the direction of the bubble, so the liquid flow is disturbed by the bubble, and the jet (print) effect of the jet unit is poor, and the final printed font is blurred.

[0077] Under this premise, for multiple jetting units (e.g., a certain jetting unit group) of a thermally driven print head, based on the consideration of the jetting algorithm, the distances between the nozzles of different jetting units and the main flow channel may be different, which will lead to inconsistent filling frequencies of different jetting units, making it impossible for the pulse frequency to match the filling frequencies of these multiple units at the same time. That is, the filling frequency of at least some of the jetting units of the print head does not match the pulse frequency. When the filling frequency of a jetting unit does not match the pulse frequency, the printing effect of the jetting unit will be poor, which will cause the overall printing effect of the print head to be unsatisfactory.

[0078] In view of this, the embodiments of the present application provide a print head, a printing component and a printing device, by structurally differentiating the design of the multiple injection units of the print head, that is, different injection units can adopt different design schemes, so that even if the distances between the nozzles (i.e., nozzles) of two injection units and the main channel are different, the filling frequencies of the two injection units can be matched with the pulse frequency at the same time (for example, the same or similar), thereby reducing or even avoiding the "empty spray" phenomenon of the injection unit, thereby improving the overall printing effect of the print head.

[0079] The present application embodiment first provides a printing device, Figure 7 Schematic diagram of the structure of the printing device provided in the embodiment of the present application. Figure 7As shown, the printing device may be, for example, a two-dimensional (2D) printer (e.g., an inkjet printer) or a three-dimensional (3D) printer, and the printing device may be, for example, a printing device in a home or office, and may be used to realize functions such as black and white paper printing, color paper printing, paint spraying, digital spray painting, digital photo printing, digital printing, digital color proofing, image and artwork reproduction, advertising spray painting or digital printing. The printing device may also be a printing device in industrial applications, for example, the printing device may be a printing device in the fields of display film encapsulation, flexible printed electronics, color filter production, liquid crystal display production, large flat flexible flat panel device production, circuit board production, biomedical field, biological tissue engineering, barcode printing, and food production.

[0080] The printing device includes a housing 500 and a printing assembly arranged in the housing 500. The printing assembly is used as a core component of the printing device to realize the printing function. The printing assembly further includes a print head 100 and a liquid storage device (such as an ink cartridge 200) for providing the print head 100 with a liquid to be sprayed. Here, the liquid to be sprayed is sprayed on the substrate by the print head 100, and the specific types of the liquid to be sprayed and the substrate are not limited in this application. In combination with the specific type or use of the printing device listed above, the liquid to be sprayed can be any fluid such as ink (such as black or any color ink), paint, edible fluid, industrial production fluid, biological fluid or medicament. The substrate can be, for example, paper, wall, billboard, circuit board (such as hard board or soft board), display panel, optical sheet, etc., any object with printing requirements.

[0081] The following takes an inkjet printer as an example to introduce the printing device provided in the embodiment of the present application.

[0082] Figure 8 Schematic diagram of the installation structure of the print head 100 provided in the embodiment of the present application. Figure 7 and Figure 8 As shown, the printing device includes an ink cartridge 200, and a print head 100 is disposed on the outer wall of the ink cartridge 200. The ink cartridge 200 stores ink, and the print head 100 is closely attached to the bottom wall of the ink cartridge 200. A through hole (channel) is provided on the bottom wall of the ink cartridge 200 so that the ink cartridge 200 can be connected to the main ink supply channel inside the print head 100 to provide ink to the print head 100. The print head 100 sprays ink from the nozzles provided on the print head 100 onto the paper 600, thereby completing the recording of text or graphics, that is, realizing the printing function.

[0083] Optionally, an ink absorbing sponge and a filter can be provided in the ink cartridge 200. The ink absorbing sponge can better preserve or maintain the ink, which is conducive to stably and reliably providing ink to the print head 100, while the filter can filter the ink about to enter the print head 100 to prevent impurities from clogging the nozzle.

[0084] Furthermore, if Figure 7 As shown, the printing device further includes an ink bottle 300 and an ink supply tube 400. The ink cartridge 200, the ink bottle 300 and the ink supply tube 400 together constitute the aforementioned liquid storage device. By providing the ink bottle 300, more ink can be stored. When the ink in the ink cartridge 200 is insufficient, the ink bottle 300 can replenish the ink to the ink cartridge 200 in time through the ink supply tube 400.

[0085] like Figure 7 As shown, the printing device also includes a controller 700, which is communicatively connected to the print head 100. The controller 700 is used to provide a pulse signal to the print head 100. Driven by the pulse signal, the print head 100 ejects ink from the nozzle onto the paper 600 outside the print head 100, thereby realizing the printing function.

[0086] Fig. 9 is a cross-sectional schematic diagram of a print head 100 provided in an embodiment of the present application. Figure 7 and Fig. 9 In the embodiment of the present application, the print head 100 may be a thermally driven print head, which is composed of a plurality of ejection units, each of which is provided with a heater 111. The controller 700 may output a pulse signal to the heater 111. After receiving the pulse signal, the heater 111 heats up rapidly, so that the ink in the chamber 121 is rapidly vaporized to form bubbles. The pressure generated by the expansion of the bubbles causes the ink to be ejected from the nozzle 131 to form fine ink droplets, which splash onto the paper 600.

[0087] Specifically, Fig. 9 As shown, a liquid supply main channel 122 is formed in the print head 100, and a plurality of ejection units are arranged around the liquid supply main channel 122, for example, the plurality of ejection units can be arranged at the edge of the liquid supply main channel 122. The liquid supply main channel 122 is connected to the ink cartridge 200 through the liquid inlet hole 112, and the ink in the ink cartridge 200 can enter the liquid supply main channel 122 through the liquid inlet hole 112. The liquid supply main channel 122 is connected to the plurality of ejection units to provide ink to the ejection units.

[0088] Each ejection unit includes a heater 111, a chamber 121, a liquid supply branch channel 123, and a nozzle 131. The liquid supply main channel 122 sequentially supplies ink to the nozzle 131 through the liquid supply branch channel 123 and the chamber 121. The heater 111 is used to generate instantaneous high temperature under the action of a pulse signal to heat the ink in the chamber 121 and generate bubbles, and the bubbles generate squeezing force to eject the ink in the nozzle 131.

[0089] like Fig. 9 As shown, the print head 100 includes a base layer 110, a chamber layer 120 and a nozzle layer 130 which are stacked in sequence. The liquid inlet 112 is formed (opened) on the base layer 110, the heater 111 is located on the inner surface of the base layer 110 and is opposite to the nozzle 131 / chamber 121, so as to heat the ink in the chamber 121, the chamber 121, the liquid supply branch channel 123 and the liquid supply main channel 122 are formed in the chamber layer 120, and the nozzle 131 is formed in the nozzle layer 130.

[0090] Optionally, the base layer 110 , the chamber layer 120 and the orifice layer 130 may be sealed and connected into an integral structure through a bonding process, and the bonding process may be, for example, anode bonding, direct bonding, plasma bonding or the like.

[0091] Optionally, the base layer 110 and the chamber layer 120 can be formed from a complete sheet (plate) by etching and other processes (that is, the base layer 110 and the chamber layer 120 originally constitute an integrated structure), and then the orifice layer 130 is formed from another sheet by etching and other processes, and then the orifice layer 130 is sealed and covered on the side of the chamber layer 120 away from the base layer 110.

[0092] Similarly, the chamber layer 120 and the orifice layer 130 may be formed from a complete sheet through etching and other processes (i.e., the chamber layer 120 and the orifice layer 130 originally constitute an integral structure), and then the base layer 110 may be formed from another sheet through etching and other processes, and then the base layer 110 may be sealed and covered on the side of the chamber layer 120 away from the orifice layer 130.

[0093] Optionally, the material of the sheet material may be, for example, silicon, glass, resin or polymer material. That is, the material of the base layer 110, the chamber layer 120 or the orifice layer 130 may include at least one of silicon, glass, resin or polymer material. For example, the base layer 110 may be a silicon base, the chamber layer 120 may be made of a resin material, and the orifice layer 130 may be made of a resin or glass material.

[0094] Fig.10 1 is a schematic diagram of the structure of the print head 100 provided in the embodiment of the present application. Fig.10Part (a) is a bottom view of the base layer 110. Fig.10 Part (b) is a top view of the chamber layer 120. Fig.10 Part (c) in FIG. 1 is a bottom view of the nozzle hole layer 130 .

[0095] like Fig.10 As shown in part (a) of the figure, the print head 100 includes a plurality of ejection units, each of which includes a heater 111, a chamber 121, a liquid supply branch channel 123, a nozzle 131 and other structures. Among them, a plurality of heaters 111 corresponding to the plurality of ejection units are arranged on the inner surface of the base layer 110, and correspond to the positions of the chambers 121, that is, the plurality of heaters 111 are directed to the plurality of chambers 121 in a one-to-one manner to heat the ink in the corresponding chambers 121. The liquid inlet 112 is provided on the base layer 110, for example, in the middle of the base layer 110, so that the ink cartridge 200 is connected to the liquid supply main channel 122, and ink can be supplied to the liquid supply main channel 122.

[0096] like Fig.10 As shown in part (b), the chamber 121, the liquid supply branch channel 123 and the liquid supply main channel 122 are formed in the chamber layer 120. Among them, the liquid supply main channel 122 is located inside the chamber layer 120, and extends from one side edge of the chamber layer 120 to the other side edge. A plurality of chambers 121 are arranged in sequence along the two side edges of the liquid supply main channel 122, and each chamber 121 is connected to the liquid supply main channel 122 through the corresponding liquid supply branch channel 123, that is, the ink in the liquid supply main channel 122 enters the corresponding chamber 121 through the liquid supply branch channel 123, and then enters the corresponding nozzle 131. The nozzle described in this application can also be understood or replaced by a nozzle.

[0097] like Fig.10 As shown in part (c) of the figure, a plurality of nozzles 131 are arranged on the nozzle layer 130 and are connected to the corresponding chambers 121. For example, the edges of the chambers 121 surround the nozzles 131. Fig. 9 as well as Fig.10 In part (b), the heater 111, the chamber 121 and the nozzle 131 are stacked in sequence, and the plurality of nozzles 131 are arranged in a staggered manner, and the distances between them and the liquid supply main channel 122 are not completely the same. For example, some nozzles 131 are closer to the liquid supply main channel 122, while some nozzles 131 are farther from the liquid supply main channel 122. Furthermore, because the distances between the plurality of nozzles 131 and the liquid supply main channel 122 are not completely the same, the lengths of the plurality of liquid supply branch channels 123 are also not completely the same, that is, some liquid supply branch channels 123 are longer, while some liquid supply branch channels 123 are shorter.

[0098] like Fig. 9 and Fig.10 As shown, the print head 100 is composed of a large number of ejection units, which can be divided into a plurality of ejection unit groups, each of which generally includes a plurality of (e.g., 3) ejection units. Based on the requirements of the ejection algorithm, the distances between the ejection units in a certain ejection unit group and the liquid supply main channel 122 are different. For example, along Fig.10 From left to right, the three spray holes 131 corresponding to the three spray units in the same spray unit group gradually approach the liquid supply main channel 122, and the distance between the spray holes 131 and the liquid supply main channel 122 decreases in equal proportion.

[0099] The print head 100 includes a plurality of jetting unit groups, and the plurality of jetting unit groups may include a first jetting unit group. Fig.11 is a schematic diagram of an example of the structure of the first injection unit group provided in the embodiment of the present application. Fig.11 As shown, the first injection unit group includes a first injection unit 141 and a second injection unit 142, wherein the distances between the spray hole 131 of the first injection unit 141 and the spray hole 131 of the second injection unit 142 and the liquid supply main channel 122 are different, for example, the spray hole 131 of the second injection unit 142 is closer to the liquid supply main channel 122.

[0100] In the embodiment of the present application, the first injection unit 141 and the second injection unit 142 are structurally differentiated in design, that is, the two injection units can adopt different design schemes, so that even if the distances between the nozzles of the two injection units and the liquid supply main channel 122 are different, the filling frequencies of the two injection units can simultaneously match the pulse frequency of the pulse signal applied to the heater (for example, the same or similar), thereby reducing or even avoiding the "empty spray" phenomenon of the injection unit and improving the overall printing effect of the print head 100.

[0101] Specifically, the heater 111 heats the ink and generates bubbles under the action of the pulse signal, the pulse frequency of the pulse signal can be recorded as f0, the filling frequency of the first ejection unit 141 is recorded as f1, and the filling frequency of the second ejection unit 142 is recorded as f2. The structures of the first ejection unit 141 and the second ejection unit 142 are set so that f1 and f2 satisfy the following relationship: 0.9≤f1 / f0≤1.1, and 0.9≤f2 / f0≤1.1. For example, f1=f2=f0, or f1 and f2 are approximately equal to (close to) f0. In other words, the filling frequency of the first ejection unit 141 matches the pulse frequency of the pulse signal applied to the heater 111, and the filling frequency of the second ejection unit 142 also matches the pulse frequency of the pulse signal applied to the heater 111. Matching here means the same or close (for example, approximately equal).

[0102] According to the print head 100 provided in the embodiment of the present application, by performing structural differentiation design on different injection units, that is, different injection units can adopt different design schemes, so that even if the distances between the nozzles 131 and the liquid supply main channel 122 of two injection units (for example, the first injection unit 141 and the second injection unit 142) are different, the filling frequencies of the two injection units can simultaneously match the pulse frequency of the pulse signal applied to the heater 111 (for example, the same or similar), that is, a larger number of injection units including the first injection unit 141 and the second injection unit 142 can simultaneously match the pulse frequency, thereby reducing or even avoiding the "empty spray" phenomenon of the injection units, and the injection ignition timing of a larger number (for example, all the number) of injection units can coincide with the downward time of the secondary oscillation, and the liquid flow direction in the nozzle 131 will be consistent with the direction of the bubble, ensuring that a larger number of injection units can obtain better printing effects, thereby improving the overall printing effect of the print head 100.

[0103] Optionally, 0<f0≤30KHz, or, 5KHz≤f0≤25KHz, or, 10KHz≤f0≤20KHz, or, 15KHz≤f0≤19KHz. For example, the value of f0 can be 3KHz, 8KHz, 12KHz, 17KHz, 19KHz or 25KHz.

[0104] For example, f0 = 20KHz, then 18KHz ≤ f1 ≤ 22KHz, 18KHz ≤ f2 ≤ 22KHz. For example, f1 = f2 = f0 = 20KHz; or f1 = f2 = 19.5KHz, or f1 = 19.8KHz, f2 = 20.3KHz.

[0105] Optionally, the filling frequency of any one of the multiple ejection units of the print head 100 is fn, 0.9≤fn / f0≤1.1. That is to say, by setting the structural details of each ejection unit, the filling frequencies of all ejection units of the print head 100 are matched with the pulse frequency of the pulse signal, and the relationship of 0.9≤fn / f0≤1.1 is satisfied, so that all ejection units will not have the "empty spray" phenomenon, and the ejection ignition timing of all ejection units can meet the downward time of the secondary oscillation, and the liquid flow direction in the nozzle 131 will be consistent with the bubble direction, thereby improving the overall printing effect of the print head 100 to a greater extent.

[0106] Furthermore, 0.95≤fn / f0≤1.05. That is, the filling frequency fn of the ejection unit is closer to the pulse frequency f0 of the pulse signal, that is, the matching degree between the filling frequency and the pulse frequency is higher, thereby further improving the ejection effect of each ejection unit, and further improving the overall printing effect of the print head 100.

[0107] For example, f0 = 20KHz, then 19KHz ≤ fn ≤ 21KHz, that is, 19KHz ≤ f1 ≤ 21KHz, 19KHz ≤ f2 ≤ 21KHz. For example, f1 = f2 = 19.8KHz, or f1 = 19.9KHz, f2 = 20.1KHz.

[0108] like Fig.10 As shown, the first injection unit group includes a first injection unit 141, a second injection unit 142 and a third injection unit 143. There is an obvious height difference between the three injection units, and the height decreases proportionally from left to right. The height difference is required by the injection algorithm.

[0109] Specifically, considering the mobility of paper during printing, in order to improve the printing effect, the three nozzles 131 corresponding to the three injection units are gradually close to the liquid supply main channel 122. The above reasons further lead to the three liquid supply branch channels 123 corresponding to the three injection units having different lengths, that is, the heights of the three injection units are different (the height gradually decreases from left to right).

[0110] That is to say, for these three injection units, the distance between the spray hole 131 of the first injection unit 141 and the main liquid supply channel 122 is the largest, the liquid supply branch channel 123 of the first injection unit 141 is the longest, and the first injection unit 141 has the highest height; the distance between the spray hole 131 of the third injection unit 143 and the main liquid supply channel 122 is the smallest, the liquid supply branch channel 123 of the third injection unit 143 is the shortest, and the third injection unit 143 has the lowest height; the second injection unit 142 is between the first injection unit 141 and the third injection unit 143.

[0111] like Fig.11 As shown, in the embodiment of the present application, the structure of at least one of the liquid supply branch channel 123, the chamber 121 or the spray hole 131 of the first spray unit 141 and the second spray unit 142 is different. That is to say, under the premise that the distances between the spray holes 131 and the liquid supply main channel 122 of the two units are different, the two spray units are designed with differentiated structures, that is, different spray units can adopt different design schemes, so that the filling frequencies of the two spray units can match the pulse frequency.

[0112] Optionally, the structures of the chambers 121 of the first spray unit 141 and the second spray unit 142 are different. For example, the two chambers 121 are different in size or shape, or in different relative positions to the spray hole 131 .

[0113] Optionally, the structures of the branch liquid supply channels 123 of the first spray unit 141 and the second spray unit 142 are different. For example, the diameters (widths) of the two branch liquid supply channels 123 are different.

[0114] Optionally, the structures of the spray holes 131 of the first spray unit 141 and the second spray unit 142 are different. For example, the sizes or shapes of the two spray holes 131 are different.

[0115] like Fig.11 As shown, in the embodiment of the present application, a first blocking member 125 is provided in each of the three liquid supply branch channels 123 corresponding to the first injection unit 141, the second injection unit 142 and the third injection unit 143. At this time, the first blocking member 125 separates the liquid supply branch channel 123 into two channels (dual channels). The shapes and / or sizes of the three first blocking members 125 are different. The ink flow rate is controlled by setting the first blocking member 125. At this time, there is no need to differentiate the design of the chamber 121 or the nozzle 131, and the filling frequencies of the three injection units can be close to or equal, that is, they can match the pulse frequency at the same time.

[0116] For example, by setting a first blocking member 125 in each liquid supply branch channel 123, the filling frequencies of the first injection unit 141, the second injection unit 142 and the third injection unit 143 are respectively 20KHz / 20.2KHz / 19.6KHz, which are accurately matched with the pulse frequency of 20KHz, and the frequency error is within the range of ±0.5KHz, thereby effectively improving the initial injection speed, droplet amount and satellite points of the injection unit, and improving the overall printing effect of the print head 100.

[0117] Optionally, the first blocking member 125 may be a blocking block. The shape of the first blocking member 125 may be any regular or irregular shape such as a triangle, a rectangle, a trapezoid, a circle, a diamond, a racetrack, etc.

[0118] Optionally, a plurality of second blocking members 125 are spaced apart in the liquid supply main channel 122 , and the second blocking members 125 may be circular blocking blocks.

[0119] Fig.12 is a schematic diagram of another example of the structure of the first injection unit group provided in the embodiment of the present application. Fig.12 As shown, relative to the aforementioned Fig.11In the embodiment shown in the present application, the first blocking member 125 is not provided in the branch liquid supply channel 123. By designing the size and / or shape of the chamber 121 differently, and designing the width of the branch liquid supply channel 123 differently, the filling frequencies of the first spray unit 141, the second spray unit 142, and the third spray unit 143 can be close to or equal, that is, they can match the pulse frequency at the same time.

[0120] Fig.13 It is a structural schematic diagram of another example of the first injection unit group provided in an embodiment of the present application. Fig.13 The embodiment shown can be regarded as the aforementioned Fig.11 and Fig.12 Specifically, as shown in the embodiment Fig.13 As shown, among the three injection units, namely the first injection unit 141, the second injection unit 142 and the third injection unit 143, a first blocking member 125 is provided in the liquid supply branch channel 123 of the first injection unit 141, while no blocking member 125 is provided in the liquid supply branch channels 123 of the other two injection units. The sizes and / or shapes of the three chambers 121 of the three injection units are different, and the widths of the three liquid supply branch channels 123 of the three injection units are also different. Through the above special-shaped design, the filling frequencies of the above three injection units can also be close to or equal, that is, they can match the pulse frequency at the same time.

[0121] Fig.14 It is a structural schematic diagram of another example of the first injection unit group provided in an embodiment of the present application. Fig.15 It is a structural schematic diagram of another example of the first injection unit group provided in an embodiment of the present application. Fig.14 and Fig.15 The main difference of the first injection unit group shown is that Fig.14 The shape of the chamber 121 is circular, and Fig.15 The shape of the chamber 121 is rectangular (eg, square). Fig.14 and Fig.15 As shown, the liquid supply branch channel 123 can be in a Y-shaped structure as a whole, and the Y-shaped structure includes a main trunk and two branches, the front end of the main trunk is connected to the liquid supply main channel 122, the rear end of the main trunk is connected to the front ends of the two branches, and the rear ends of the two branches are connected to the chamber 121. By setting the liquid supply branch channel 123 as a Y-shaped structure, the liquid supply branch channel 123 can have a non-return characteristic, reducing the backflow of ink can greatly reduce the time of replenishing liquid, and thus the filling frequency of the injection unit can be better adjusted and controlled.

[0122] Specifically, Fig.14As shown, in the replenishment stage, the ink enters the main branch of the liquid supply channel 123 from the main liquid supply channel 122, and then enters the chamber 121 through the two branches. In the injection stage, the ink retreats from the chamber 121 toward the two branches. At this time, the ink returning from the two branches will conflict with each other at the confluence point of the main branch, and the kinetic energy of the retreat is offset, resulting in the ink in the entire liquid supply channel 123 not being able to return smoothly, or the amount of returned ink is relatively small. Reducing the ink return can greatly reduce the time of replenishment.

[0123] Optionally, the angle formed between the two branches can be an obtuse angle, in which case the kinetic energy of the ink flowing back from the two branches can be relatively fully offset, thereby ensuring that the liquid supply branch channel 123 has a sufficiently reliable anti-return characteristic.

[0124] Optionally, the first blocking member 125 may be provided in the branch liquid supply channel 123 so that the branch liquid supply channel 123 as a whole forms a Y-shaped structure.

[0125] Furthermore, if Fig.14 and Fig.15 As shown, one branch of the Y-shaped structure (i.e., the liquid supply branch channel 123) is a J-shaped hook structure. Through the above arrangement, the ink flowing back in the two branches can be offset as much as possible, and the kinetic energy of the ink flowing back in the two branches can be relatively fully offset, thereby ensuring that the liquid supply branch channel 123 has a sufficiently reliable anti-return characteristic.

[0126] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A print head, characterized in that: include: Main flow channel for liquid supply; A plurality of spray units, each of which comprises a heater and a spray hole, wherein the spray hole is used to receive the liquid to be sprayed from the liquid supply main channel, and the heater is used to heat the liquid to be sprayed and generate bubbles under the action of a pulse signal, wherein the pulse frequency of the pulse signal is f0; The multiple injection units include a first injection unit and a second injection unit. The distances between the injection holes of the first injection unit and the injection holes of the second injection unit and the liquid supply main channel are different. The filling frequency of the first injection unit is f1, and the filling frequency of the second injection unit is f2. 0.9≤f1 / f0≤1.1, 0.9≤f2 / f0≤1.

1.

2. The print head according to claim 1, characterized in that: A filling frequency of any one of the plurality of injection units is fn, and 0.9≤fn / f0≤1.

1.

3. The print head according to claim 2, characterized in that: 0.95≤fn / f0≤1.

05.

4. The print head according to any one of claims 1 to 3, characterized in that: The first spray unit and the second spray unit belong to a first spray unit group, and the distances between the spray holes of the plurality of spray units in the first spray unit group and the liquid supply main channel decrease in sequence.

5. The print head according to any one of claims 1 to 4, characterized in that: The spray unit further comprises a chamber and a liquid supply branch channel, and the liquid supply main channel sequentially supplies the liquid to be sprayed to the spray hole through the liquid supply branch channel and the chamber.

6. The print head according to claim 5, characterized in that: The structure of at least one of the liquid supply branch channel, the chamber or the spray hole of the first spray unit and the second spray unit is different.

7. The print head according to claim 5 or 6, characterized in that: A first blocking member is disposed in the liquid supply branch channel of the first spray unit and / or the second spray unit.

8. The print head according to claim 7, characterized in that: The structures of the first blocking member disposed in the liquid supply branch channel of the first spray unit and the second spray unit are different.

9. The print head according to any one of claims 5 to 8, characterized in that: The liquid supply branch channel of the first injection unit is in a Y-shaped structure as a whole, and two branches of the Y-shaped structure are connected to the chamber.

10. The print head according to claim 9, characterized in that: At least one branch in the Y-shaped structure is a J-shaped hook structure.

11. The print head according to any one of claims 5 to 10, characterized in that: The print head includes a base layer, a chamber layer and a nozzle layer which are stacked in sequence. The heater is located on the inner surface of the base layer to heat the liquid to be sprayed in the chamber. The chamber, the liquid supply branch channel and the liquid supply main channel are formed in the chamber layer, and the nozzle is formed in the nozzle layer.

12. A printing assembly, characterized in that: The invention comprises a print head as claimed in any one of claims 1 to 11, and a liquid storage device for providing the print head with liquid to be ejected.

13. The printing assembly according to claim 12, characterized in that: The liquid storage device comprises an ink cartridge, and the print head is arranged on the outer wall of the ink cartridge.

14. A printing device, characterized in that: include: A print head as claimed in any one of claims 1 to 11, or a printing assembly as claimed in claim 12 or 13; as well as, A controller is used for providing a pulse signal to the print head.

15. The printing device according to claim 14, characterized in that The printing device is an inkjet printer.

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