Liquid ejection device and control method of liquid ejection device

Abstract

The present disclosure provides a liquid ejection device and a control method for the liquid ejection device. In the liquid ejection device of the present disclosure, which is provided with a liquid ejection head for ejecting a liquid containing particles, a circulation mechanism for adjusting the flow rate of the liquid circulating in the liquid ejection head, and a control device for controlling the operation of the circulation mechanism, the liquid ejection head has a pressure chamber, a supply flow channel, a nozzle flow channel, a nozzle, and a discharge flow channel. When a first liquid containing particles with an average particle size of a first particle size is supplied to the liquid ejection head, the control device controls the circulation mechanism in such a manner that the circulation flow rate of the first liquid in the supply flow channel, the nozzle flow channel, and the discharge flow channel becomes a first flow rate. When a second liquid containing particles with an average particle size of a second particle size larger than the first particle size is supplied to the liquid ejection head, the circulation mechanism is controlled in such a manner that the circulation flow rate of the second liquid becomes a second flow rate smaller than the first flow rate.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection device and a control method thereof. Background Art

[0002] A technique is known in which, in order to improve the stability of liquid ejection operation in a liquid ejecting head, the circulation amount of liquid is increased as the amount of liquid ejected per unit time increases (for example, Patent Document 1).

[0003] In the conventional technology, the physical properties of the discharged liquid are not taken into consideration, and thus the performance of the liquid may be degraded.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-14194 Summary of the Invention

[0005] According to a first aspect of the present disclosure, a liquid ejection device is provided, comprising: a liquid ejection head that ejects a liquid containing particles; a circulation mechanism that adjusts the flow rate of the liquid circulating in the liquid ejection head; and a control device that controls the operation of the circulation mechanism. In the liquid ejection device, the liquid ejection head comprises: a pressure chamber for applying pressure to the liquid; a supply flow channel that communicates with the pressure chamber; a nozzle flow channel that communicates with the supply flow channel; a nozzle that is disposed on the nozzle flow channel and ejects the liquid by pressure applied by the pressure chamber; and a discharge flow channel that is connected to the opposite side of the nozzle flow channel from the nozzle. The control device controls the circulation mechanism in a manner that makes the circulation flow rate of the first liquid in the supply flow channel, the nozzle flow channel and the discharge flow channel become a first flow rate when a first liquid containing particles with an average particle size of a first particle size is supplied to the liquid ejection head, and controls the circulation mechanism in a manner that makes the circulation flow rate of the second liquid become a second flow rate less than the first flow rate when a second liquid containing particles with an average particle size of a second particle size larger than the first particle size is supplied to the liquid ejection head.

[0006] According to a second aspect of the present disclosure, a liquid ejection device is provided, comprising: a liquid ejection head that ejects a liquid containing particles; a circulation mechanism that adjusts the flow rate of the liquid circulating in the liquid ejection head; and a control device that controls the operation of the circulation mechanism. In the liquid ejection device, the liquid ejection head comprises: a pressure chamber for applying pressure to the liquid; a supply channel connected to the pressure chamber; a nozzle channel connected to the supply channel; a nozzle disposed on the nozzle channel that ejects the liquid by pressure applied by the pressure chamber; and a discharge channel connected to the side of the nozzle channel opposite to the nozzle. The control device controls the circulation mechanism so that the circulation flow rate of the first liquid in the nozzle channel is a first flow rate when a first liquid having a first viscosity is supplied to the liquid ejection head, and controls the circulation mechanism so that the circulation flow rate is a fourth flow rate greater than the first flow rate when a fourth liquid having a second viscosity greater than the first viscosity is supplied to the liquid ejection head.

[0007] According to a third aspect of the present disclosure, a method for controlling a liquid ejection device is provided. In the method, when a first liquid containing particles having an average particle size of a first particle size is supplied to a liquid ejection head, a circulation flow rate of the first liquid within the liquid ejection head is set to a first flow rate, and when a second liquid containing particles having an average particle size of a second particle size larger than the first particle size is supplied to the liquid ejection head, the circulation flow rate of the second liquid within the liquid ejection head is set to a second flow rate smaller than the first flow rate.

[0008] According to a fourth aspect of the present disclosure, a method for controlling a liquid ejection device is provided. In the method, when a first liquid having a first viscosity is supplied to a liquid ejection head, a circulation flow rate of the first liquid within the liquid ejection head is set to a first flow rate, and when a fourth liquid having a second viscosity greater than the first viscosity is supplied to the liquid ejection head, the circulation flow rate of the fourth liquid within the liquid ejection head is set to a fourth flow rate greater than the first flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is an explanatory diagram showing an example of the liquid ejecting device according to the first embodiment.

[0010] Figure 2 This is an exploded perspective view of the liquid ejection head.

[0011] Figure 3 for Figure 2Cross-sectional view along line III-III.

[0012] Figure 4 This is a top view of the liquid ejection head as viewed from the -Z direction.

[0013] Figure 5 This is an enlarged cross-sectional view of the vicinity of the piezoelectric element.

[0014] Figure 6 This is a graph showing simulation results for evaluating the correlation between ink viscosity and the probability of ink particles existing in the nozzle Nz.

[0015] Figure 7 This is a graph showing simulation results for evaluating the correlation between the particle size of a color material and the probability of particle existence.

[0016] Figure 8 This is a graph showing simulation results for evaluating the correlation between the ink ejection amount and the probability of particle existence.

[0017] Figure 9 This is a graph showing simulation results for evaluating the correlation between the circulation flow rate and the probability of particle existence.

[0018] Figure 10 This is a flowchart showing a control method of the liquid ejecting device executed by the control device of this embodiment.

[0019] Figure 11 This is an explanatory diagram showing parameter settings of the liquid ejection device according to another first embodiment.

[0020] Figure 12 This is an explanatory diagram showing parameter settings of the liquid ejection device according to another second embodiment.

[0021] Figure 13 This is an explanatory diagram showing parameter settings of the liquid ejection device according to another third embodiment.

[0022] Figure 14 This is an explanatory diagram showing parameter settings of the liquid ejection device according to another fourth embodiment.

[0023] Figure 15 This is a second explanatory diagram showing parameter settings of the liquid ejection device according to another fourth embodiment.

[0024] Figure 16 This is an explanatory diagram showing parameter settings of the liquid ejection device according to another fifth embodiment. DETAILED DESCRIPTION

[0025] A. First embodiment:

[0026] Figure 1 This is an explanatory diagram showing an example of a liquid ejection device 100 according to the first embodiment. The liquid ejection device 100 according to the first embodiment is an inkjet printing device that ejects ink onto a medium PP such as printing paper. In addition to printing paper, any printing object such as a resin film or cloth can also be used as the medium PP. Figure 1 , the X-axis, Y-axis, and Z-axis directions are shown. The X-axis direction includes the +X direction and the -X direction, which is the direction opposite to the +X direction. The Y-axis direction includes the +Y direction and the -Y direction, which is the direction opposite to the +Y direction. The Z-axis direction includes the +Z direction and the -Z direction, which is the direction opposite to the +Z direction. The X-axis, Y-axis, and Z-axis directions are mutually orthogonal. Figure 1 The X-axis direction, Y-axis direction, and Z-axis direction shown in FIG. Figure 1 This is also common to the subsequent drawings.

[0027] like Figure 1 As shown, the liquid ejection device 100 includes: a plurality of liquid ejection heads 1 for ejecting a liquid containing particles; one or more control devices 90; a liquid container 93; and a circulation mechanism 94. The control device 90 is, for example, a microcomputer including a microprocessor such as a CPU or FPGA and a storage circuit such as a semiconductor memory. The control device 90 controls the operation of each component of the liquid ejection device 100 by executing a program pre-stored in the storage circuit.

[0028] Liquid is stored in the liquid container 93. For example, the liquid may be an ink in which a pigment serving as a coloring material is dispersed in a solvent. In addition to inks containing pigments, the liquid may also be an ink containing dyes, or an ink containing both pigments and dyes as coloring materials. Inks include conventional aqueous and oil-based inks, as well as various liquid compositions such as gel inks and hot-melt inks. For example, the liquid container 93 may be a cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink bag formed of a flexible film, or an ink tank capable of refilling ink.

[0029] In this embodiment, the control device 90 can obtain information about the viscosity of the ink stored in the liquid container 93 or the particle size of a colorant such as a pigment contained in the ink. The control device 90 can obtain the viscosity or particle size of the liquid by, for example, detecting viscosity or particle size information pre-stored in a chip (not shown) included in the liquid container 93, or manually inputting the information into the control device 90 by a user of the liquid ejection device 100. In this embodiment, the liquid container 93 stores multiple types of inks of different colors. Specifically, the liquid container 93 stores two types of liquids, a first liquid and a second liquid, described below.

[0030] The circulation mechanism 94 is a pump that supplies the liquid stored in the liquid container 93 to the liquid ejection head 1. In this embodiment, the circulation mechanism 94 can select any one liquid from the multiple types of liquids stored in the liquid container 93 under the control of the control device 90 and supply it to one liquid ejection head 1. That is, in the liquid ejection head 1 of this embodiment, the type of liquid is switched by the control device 90, so that each of the multiple types of liquids can be supplied separately. As described later, the circulation mechanism 94 can adjust the circulation flow rate of the ink in the liquid ejection head 1 under the control of the control device 90. The circulation mechanism 94 recovers the ink stored in the liquid ejection head 1 and returns the recovered ink to the liquid ejection head 1.

[0031] The liquid ejection device 100 of this embodiment also includes a moving mechanism 91 and a conveying mechanism 92. Under the control of the control device 90, the moving mechanism 91 conveys the medium PP in the +Y direction. The conveying mechanism 92 includes a storage housing 921 for accommodating a plurality of liquid ejection heads 1, and an endless belt 922 to which the storage housing 921 is fixed. Under the control of the control device 90, the conveying mechanism 92 causes the liquid ejection head 1 to reciprocate along the X-axis direction by operating the endless belt 922 to which the storage housing 921 is fixed. The conveying direction of the medium PP and the moving direction of the liquid ejection head 1 are not limited to being orthogonal, but may also intersect at a predetermined angle. The liquid container 93 and the circulation mechanism 94 may also be housed in the storage housing 921 together with the liquid ejection head 1.

[0032] like Figure 1As shown, the control device 90 outputs a drive signal Com for driving the liquid ejection head 1 and a control signal SI for controlling the liquid ejection head 1 to the liquid ejection head 1. Under the control of the control signal SI, the liquid ejection head 1 is driven by the drive signal Com, causing ink to be ejected from some or all of the multiple nozzles provided in the liquid ejection head 1. In this embodiment, the ink is ejected in the +Z direction. While the transport of the medium PP by the moving mechanism 91 and the reciprocating movement of the liquid ejection head 1 by the transport mechanism 92 are linked, the liquid ejection head 1 ejects ink from the nozzles, causing the ink to land on the surface of the medium PP. As a result, the desired image is formed on the surface of the medium PP. The ink ejection direction is not limited to the +Z direction and may be any direction intersecting the XY plane.

[0033] use Figures 2 to 5 The liquid ejecting head 1 will be described in detail. Figure 2 It is an exploded perspective view of the liquid ejecting head 1. Figure 3 for Figure 2 Cross-sectional view along line III-III. Figure 4 It is a top view of the liquid ejection head 1 when viewed from the -Z direction. Figure 2 As shown, the liquid ejecting head 1 includes a nozzle substrate 60 , a communication plate 2 , a pressure chamber substrate 3 , a vibration plate 4 , a storage chamber forming substrate 5 , a wiring substrate 8 , and compliance sheets 61 and 62 .

[0034] like Figure 2 As shown, the nozzle substrate 60 is a plate-shaped member extending along the Y-axis. The nozzle substrate 60 is arranged approximately parallel to the XY plane. The nozzle substrate 60 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing techniques such as etching. M nozzles Nz are formed on the nozzle substrate 60. M is a natural number greater than or equal to 1. The nozzles Nz are through-holes provided in the nozzle substrate 60. In this embodiment, the M nozzles Nz are arranged on the nozzle substrate 60 to form a nozzle column Ln extending in the Y-axis direction.

[0035] like Figure 2 As shown, a connecting plate 2 is provided on the -Z-side surface of the nozzle substrate 60. The connecting plate 2 is a plate-shaped member extending along the Y-axis. The connecting plate 2 is positioned approximately parallel to the XY plane. The connecting plate 2 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing technology.

[0036] like Figure 2As shown in FIG, an ink flow path is formed in the connecting plate 2. Specifically, a common supply flow path RA1 extending in the Y-axis direction and a common discharge flow path RA2 extending in the Y-axis direction are formed in the connecting plate 2. Figure 3 As shown, the connecting plate 2 further includes M nozzle flow channels RN, M supply flow channels RR1, M discharge flow channels RR2, M communication flow channels RK1, M communication flow channels RK2, M communication flow channels RX1, and M communication flow channels RX2, corresponding to each of the M nozzles Nz. The connecting plate 2 may include one communication flow channel RX1 common to the M nozzles Nz, and one communication flow channel RX2 common to the M nozzles Nz.

[0037] like Figure 3 As shown, the connecting flow channel RX1 is connected to the common supply flow channel RA1. The connecting flow channel RX1 is provided in a manner extending from the common supply flow channel RA1 along the X-axis direction toward the -X direction. The connecting flow channel RK1 is connected to the connecting flow channel RX1. The connecting flow channel RK1 is provided in a manner extending from the connecting flow channel RX1 along the Z-axis direction toward the -Z direction. The connecting flow channel RK1 is connected to one end of the pressure chamber CB1 described later. The supply flow channel RR1 is connected to the other end of the pressure chamber CB1. The supply flow channel RR1 is provided in a manner extending from the pressure chamber CB1 along the Z-axis direction toward the +Z direction. The supply flow channel RR1 is connected to one end of the nozzle flow channel RN. In the nozzle flow channel RN, a nozzle Nz corresponding to the nozzle flow channel RN is provided. In addition, as shown in FIG. Figure 2 、 Figure 3 As shown, in this embodiment, the width of the nozzle flow channel RN in the +Z direction is greater near the nozzle Nz than outside the nozzle Nz. This increases the flow rate of the ink near the nozzle Nz, preventing ink from stagnating near the nozzle Nz due to thickening, etc., thereby suppressing a decrease in ejection characteristics. However, this embodiment is not limited to this. For example, the width of the nozzle flow channel RN in the +Z direction and the width of the nozzle flow channel RN in the +Y direction may be the same near the nozzle Nz and outside the nozzle Nz.

[0038] The other end of the nozzle flow channel RN is connected to the discharge flow channel RR2. The discharge flow channel RR2 is provided in a manner extending from the nozzle flow channel RN along the Z-axis direction toward the -Z direction. The discharge flow channel RR2 is connected to one end of the pressure chamber CB2 described later. The other end of the pressure chamber CB2 is connected to the connecting flow channel RK2. The connecting flow channel RK2 is provided in a manner extending from the pressure chamber CB2 along the Z-axis direction toward the +Z direction. One end of the connecting flow channel RX2 is connected to the connecting flow channel RK2. The connecting flow channel RX2 is provided in a manner extending from the connecting flow channel RK2 along the X-axis direction toward the -X direction. The other end of the connecting flow channel RX2 is connected to the common discharge flow channel RA2.

[0039] like Figure 2 as well as Figure 3 As shown, a plastic thin plate 61 is provided on the surface of the connecting plate 2 on the +Z direction side to seal the common supply flow channel RA1, the connecting flow channel RX1, and the connecting flow channel RK1. The plastic thin plate 61 is made of, for example, an elastic material. The plastic thin plate 61 absorbs pressure fluctuations of the ink within the common supply flow channel RA1, the connecting flow channel RX1, and the connecting flow channel RK1. A plastic thin plate 62 is provided on the surface of the connecting plate 2 on the +Z direction side to seal the common discharge flow channel RA2, the connecting flow channel RX2, and the connecting flow channel RK2. The plastic thin plate 62 is made of, for example, an elastic material and absorbs pressure fluctuations of the ink within the common discharge flow channel RA2, the connecting flow channel RX2, and the connecting flow channel RK2.

[0040] like Figure 2 as well as Figure 3 As shown, a reservoir-forming substrate 5 is provided on the -Z-direction surface of the connecting plate 2. The reservoir-forming substrate 5 is a member extending in the Y-axis direction. The reservoir-forming substrate 5 is formed, for example, by injection molding of a resin material. An ink flow path is formed within the reservoir-forming substrate 5. Specifically, a common supply flow channel RB1 and a common discharge flow channel RB2 are formed within the reservoir-forming substrate 5. The common supply flow channel RB1 communicates with the common supply flow channel RA1, and the common discharge flow channel RB2 communicates with the common discharge flow channel RA2.

[0041] The reservoir forming substrate 5 is provided with an inlet 51 communicating with the common supply flow path RB1 and a discharge port 52 communicating with the common discharge flow path RB2. Ink from the liquid container 93 is supplied to the common supply flow path RB1 via the inlet 51. Furthermore, ink stored in the common discharge flow path RB2 is recovered via the discharge port 52.

[0042] In this embodiment, ink supplied from the liquid container 93 to the inlet 51 via the circulation mechanism 94 flows into the common supply channel RA1 via the common supply channel RB1. A portion of the ink flowing into the common supply channel RA1 is divided into the connecting channel RX1 and the connecting channel RK1, thereby flowing into each pressure chamber CB1. A portion of the ink flowing into the pressure chamber CB1 flows sequentially through the supply channel RR1, the nozzle channel RN, and the discharge channel RR2, thereby flowing into the pressure chamber CB2. A portion of the ink flowing into the pressure chamber CB2, after passing through the connecting channel RK2 and the connecting channel RX2, merges with the common discharge channel RA2, and is discharged from the discharge port 52 via the common discharge channel RB2. In the following description, the ink flow path from the common supply channel RA1 to the common discharge channel RA2 is also referred to as the circulation channel RJ. Specifically, the circulation channel RJ includes a common supply channel RA1, a communication channel RX1, a communication channel RK1, a pressure chamber CB1, a supply channel RR1, a nozzle channel RN, a discharge channel RR2, a pressure chamber CB2, a communication channel RK2, a communication channel RX2, and a common discharge channel RA2. Figure 4 As shown, the common supply flow path RA1 and the common discharge flow path RA2 are connected together by M circulation flow paths RJ corresponding to each of the M nozzles Nz.

[0043] like Figure 2 as well as Figure 3 As shown, an opening 50 is provided on the storage chamber forming substrate 5. Inside the opening 50, a pressure chamber substrate 3, a vibration plate 4 and a wiring substrate 8 are provided. The pressure chamber substrate 3 is a plate-like component that is long in the Y-axis direction. The pressure chamber substrate 3 is provided on the surface on the -Z direction side of the connecting plate 2. The pressure chamber substrate 3 is configured in a manner that is approximately parallel to the XY plane. The pressure chamber substrate 3 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing technology. An ink flow path is formed in the pressure chamber substrate 3. Specifically, in the pressure chamber substrate 3, M pressure chambers CB1 and M pressure chambers CB2 corresponding to each of the M nozzles Nz are formed.

[0044] Pressure chamber CB1 is provided to extend in the X-axis direction so as to connect communication channel RK1 and supply channel RR1. Pressure chamber CB2 is provided to extend in the X-axis direction so as to connect communication channel RK2 and discharge channel RR2. In the following description, when pressure chamber CB1 and pressure chamber CB2 are not distinguished, they are also referred to as pressure chamber CBq.

[0045] The vibration plate 4 is a plate-shaped component that is long in the Y-axis direction. Figure 2 as well as Figure 3As shown, the vibration plate 4 is provided on the surface on the -Z direction side of the pressure chamber substrate 3. The vibration plate 4 is a component that can vibrate elastically and applies pressure to the liquid in the pressure chamber CBq. The vibration plate 4 is configured in a manner that is approximately parallel to the XY plane. On the surface on the -Z direction side of the vibration plate 4, M piezoelectric elements PZ1 corresponding to each of the M pressure chambers CB1, and M piezoelectric elements PZ2 corresponding to each of the M pressure chambers CB2 are provided. In the following description, when the piezoelectric element PZ1 and the piezoelectric element PZ2 are not distinguished, they are also referred to as piezoelectric elements PZq. The piezoelectric element PZq is an energy conversion element that converts the electrical energy of the drive signal Com into kinetic energy. In the present embodiment, the piezoelectric element PZq is a passive element that deforms according to the potential change of the drive signal Com.

[0046] The wiring substrate 8 is mounted on the -Z side of the vibration plate 4. The wiring substrate 8 is a component used to electrically connect the control device 90 and the liquid ejection head 1. A flexible wiring substrate such as an FPC (Flexible Print Circuit) or an FFC (Flexible Flat Cable) can be used as the wiring substrate 8. A drive circuit 81 is mounted on the wiring substrate 8. Based on the control signal SI, the drive circuit 81 switches whether the drive signal Com is supplied to the piezoelectric element PZq.

[0047] Figure 5 This is an enlarged cross-sectional view of the vicinity of the piezoelectric element PZq. Figure 5 As shown, the piezoelectric element PZq is a laminate in which the piezoelectric body ZMq is interposed between the lower electrode ZDq and the upper electrode ZUq. A pressure chamber CBq is provided on the +Z direction side of the piezoelectric element PZq. A predetermined reference potential is supplied to the lower electrode ZDq. The drive circuit 81 supplies a drive signal Com to the upper electrode ZUq via the wiring 810. The drive signal Com supplied to the piezoelectric element PZ1 is also referred to as the drive signal Com1, and the drive signal Com supplied to the piezoelectric element PZ2 is also referred to as the drive signal Com2. In this embodiment, when ink is ejected from the nozzle Nz, the waveform of the drive signal Com1 supplied by the drive circuit 81 to the piezoelectric element PZ1 corresponding to the nozzle Nz and the waveform of the drive signal Com2 supplied by the drive circuit 81 to the piezoelectric element PZ2 corresponding to the nozzle Nz are substantially the same.

[0048] The piezoelectric element PZq deforms in response to changes in the potential of the drive signal Com. The vibration plate 4 vibrates in conjunction with the deformation of the piezoelectric element PZq. The vibration of the vibration plate 4 causes the pressure in the pressure chamber CBq to fluctuate. Due to the pressure fluctuations in the pressure chamber CBq, the ink filled in the pressure chamber CBq is ejected from the nozzle Nz via the supply flow channel RR1, the discharge flow channel RR2, and the nozzle flow channel RN. Specifically, when the piezoelectric element PZ1 is driven by the drive signal Com1, a portion of the ink filled in the pressure chamber CB1 is ejected from the nozzle Nz via the supply flow channel RR1 and the nozzle flow channel RN. When the piezoelectric element PZ2 is driven by the drive signal Com2, a portion of the ink filled in the pressure chamber CB2 is ejected from the nozzle Nz via the discharge flow channel RR2 and the nozzle flow channel RN.

[0049] The liquid ejection device 100 of this embodiment circulates ink from the common supply flow channel RA1 through the circulation flow channel RJ to the common discharge flow channel RA2. Therefore, even when there are periods when ink within the pressure chamber CBq is not ejected from the nozzles Nz, it is possible to reduce or prevent ink from accumulating within the pressure chamber CBq and in the nozzle flow channel RN. Consequently, the liquid ejection device 100 of this embodiment can reduce or prevent the thickening of ink within the pressure chamber CBq and the nozzle flow channel RN, thereby reducing or preventing the occurrence of ejection abnormalities where ink cannot be ejected from the nozzles Nz.

[0050] The liquid ejection device 100 of this embodiment ejects the ink filled in the pressure chamber CB1 and the ink filled in the pressure chamber CB2 from a single nozzle Nz. Therefore, for example, the liquid ejection device 100 of this embodiment can increase the amount of ink ejected from the nozzle Nz compared to a method in which only the ink filled in one pressure chamber CBq is ejected from the nozzle Nz.

[0051] In the liquid ejection device 100 of this embodiment, ink parameters and setting conditions for the liquid ejection head 1 are further set based on simulation results of the particle presence probability in nozzles Nz. The particle presence probability refers to the probability of particles existing per unit volume of ink. To ensure optimal performance of the ink, a high particle presence probability is preferred. Specifically, the particle presence probability is preferably 60% or greater, and more preferably 80% or greater.

[0052] The parameters of the ink include the viscosity of the ink and the particle size of the color material contained in the ink. The setting conditions of the liquid ejection head 1 include the circulation flow rate of the ink in the liquid ejection head 1 and the ejection amount of the ink ejected from the nozzle Nz. The circulation flow rate of the ink means, for example, the flow rate of the ink flowing in the flow channels in the liquid ejection head 1, such as the supply flow channel RR1, the nozzle flow channel RN and the discharge flow channel RR2. The circulation flow rate of the ink can be adjusted by the circulation mechanism 94. Specifically, by increasing the output of the circulation mechanism 94, the circulation flow rate of the ink flowing in the nozzle flow channel RN is increased. From the viewpoint of suppressing the thickening of the ink, the circulation flow rate is preferably 1E-13m 2 / s or more, more preferably 1E-12m 2 The amount of ink ejected from the nozzle Nz can be adjusted by, for example, varying the potential of the drive signal Com supplied to the piezoelectric element PZq. Specifically, increasing the potential variation of the drive signal Com supplied to the piezoelectric element PZq increases the amount of ink ejected.

[0053] use Figures 6 to 9 The following describes the results of a simulation that demonstrates the correlation between ink parameters and the settings of the liquid ejection device 100 and the probability of particle presence in the nozzles Nz. The simulation evaluated the effects of various factors, including the ink viscosity and the particle size of the colorant contained in the ink as ink parameters, and the ink circulation flow rate and the amount of ink ejected from the nozzles Nz as settings of the liquid ejection device 100, on the probability of particle presence in the nozzles Nz.

[0054] Figure 6 : is a graph showing simulation results for evaluating the correlation between the viscosity of ink and the probability of existence of particles in the ink within the nozzle Nz. Figure 6 The vertical axis represents the viscosity of the ink, and the horizontal axis represents the probability of particles existing in the nozzle Nz. The setting conditions of the liquid ejection device 100 are as follows: the ejection volume 3E-12m 2 / s, circulation flow rate 1.2E-9m 2 / s. The particle size of the color material contained in the ink is 5 μm.

[0055] like Figure 6As shown, when the viscosity is 1 mPa·s, the probability of particles existing in the nozzle Nz is 6.3%. When the viscosity is 4 mPa·s, the probability of particles existing is 55.2%. When the viscosity is 40 mPa·s, the probability of particles existing is 100%. In this way, the probability of particles existing in the nozzle Nz increases as the viscosity becomes higher. Generally speaking, the lower the viscosity of a liquid, the easier it is for the particles contained in the liquid to settle. Therefore, the particles contained in the liquid are less likely to be affected by the force generated by the flow of the liquid. Therefore, it can be considered that the reason why the probability of particles existing in the nozzle Nz is smaller as the viscosity of the ink is lower is that even if ink with a lower viscosity flows in the nozzle channel RN, the particles are less likely to be affected by the force generated by the flow of the ink, and thus it is difficult for the particles to flow from the nozzle channel RN to the nozzle Nz.

[0056] Figure 7 : is a graph showing simulation results for evaluating the correlation between the particle diameter of particles contained in ink and the probability of particles existing in the nozzle Nz. Figure 7 The vertical axis represents the particle size of the color material, and the horizontal axis represents the probability of particles existing in the nozzle Nz. As the setting condition of the liquid ejection device 100, the ejection amount is 3E-12m 2 / s, the circulation flow rate is 1.2E-9m 2 The viscosity of the ink was set to 4 mPa·s.

[0057] like Figure 7 As shown, the simulated probability of particle presence is 55.2% at a particle size of 5 μm. At a particle size of 8 μm, the probability is 12.6%. Thus, the probability of particle presence in nozzle Nz decreases as the particle size increases. Generally speaking, the larger the particle size of a liquid, the more susceptible it is to the forces generated by the liquid's flow. It is believed that the reason the probability of particle presence in nozzle Nz decreases with increasing particle size is that the particles are affected by the flow of ink from nozzle channel RN to nozzle Nz, making them more likely to flow to nozzle Nz.

[0058] Figure 8 : is a graph showing simulation results for evaluating the correlation between the ink discharge amount and the probability of particle existence in the nozzle Nz. Figure 8 The vertical axis represents the ejection amount of ink ejected from the nozzle Nz, and the horizontal axis represents the probability of particles existing in the nozzle Nz. As the setting conditions of the liquid ejection device 100, the circulation flow rate is 1.2E-9m 2 The viscosity of the ink is 1 mPa·s, and the particle size of the color material contained in the ink is 5 μm.

[0059] like Figure 8 As shown, when the ink ejection volume is 3E-12m2 / s, the particle existence probability shows 6.3%. 2 / s, the particle presence probability shows 93.4%. Thus, the probability of particle presence in nozzle Nz increases with increasing ejection volume. Generally speaking, the greater the ejection volume of ink from nozzle Nz, the greater the amount of ink supplied to nozzle Nz. It is believed that the reason why the probability of particle presence in nozzle Nz increases with increasing ink ejection volume is that particles are affected by the ink flowing into nozzle Nz, making them more likely to be supplied to nozzle Nz.

[0060] Figure 9 : is a graph showing simulation results for evaluating the correlation between the circulation flow rate and the probability of particle existence in the nozzle Nz. Figure 9 The vertical axis represents the circulation flow rate of ink, and the horizontal axis represents the probability of particles existing in the nozzle Nz. As the setting condition of the liquid ejection device 100, the ejection amount is 3E-12m 2 The viscosity of the ink is 4 mPa·s, and the particle size of the color material contained in the ink is 5 μm.

[0061] like Figure 9 As shown, when the circulation flow rate is 1.2E-9m 2 / s, the probability of particle existence is 55.2%. 2 / s, the probability of particle existence is 61.9%. 2 / s, the particle presence probability is 72.9%. Thus, the particle presence probability in nozzle Nz increases as the circulation flow rate decreases. A higher circulation flow rate results in a higher flow rate of ink in nozzle channel RN. As the flow rate of ink in nozzle channel RN increases, particles are more susceptible to the force generated by the flow of ink in nozzle channel RN. Therefore, it is believed that this is due to the difficulty in supplying particles from nozzle channel RN to nozzle Nz.

[0062] Figure 10 1 is a flow chart showing a control method of a liquid ejection device executed by the control device 90 of this embodiment. This process is started, for example, by turning on the power of the liquid ejection device 100. In this process, the ejection amount is a fixed value and is set to 3E-12m 2 / s. This process can also be started when the replacement of the liquid container 93 is completed. In the liquid ejection device 100 of this embodiment, the circulation flow rate is set to 1E-12m / s from the perspective of suppressing the thickening of the ink. 2 / s or more, and to suppress degradation of ink performance, the particle existence probability is made 60% or more, and the above-described simulation results are reflected in the ink parameters and the setting conditions of the liquid ejection device 100 .

[0063] In step S10, the control device 90 obtains information on the viscosity and average particle size of the ink. The control device 90 detects a chip (not shown) included in the liquid container 93 to obtain ink parameters such as the average viscosity or particle size of the ink within the liquid container 93. Alternatively, the control device 90 may include a mechanism for measuring the average viscosity or particle size of the ink within the liquid ejection device 100. Furthermore, the liquid ejection device 100 may include an input unit and a display, or the user may input information into the input unit based on the display, thereby causing the control device 90 to obtain the average viscosity or particle size of the ink. In step S20, a determination is made as to whether the obtained average particle size is greater than a predetermined threshold. In this embodiment, the predetermined threshold in step S20 is set to 6 μm. If the obtained average particle size is less than 6 μm (S20: No), the control device 90 proceeds to step S30 and determines the ink particle size to be the first particle size.

[0064] In step S40, the control device 90 compares the obtained ink viscosity with a predetermined threshold value. In this embodiment, the predetermined threshold value in step S40 is set to 3 mPa·s. If the ink viscosity is less than 3 mPa·s (S40: No), the control device 90 proceeds to step S50 and determines that the ink viscosity is the first viscosity. Ink containing particles having the first particle size and the first viscosity is also referred to as the first liquid.

[0065] In step S60, the control device 90 controls the operation of the circulation mechanism 94 so that the circulation flow rate of the first liquid becomes the first flow rate. The first flow rate means that the first flow rate is included in the range of 1E-12m 2 / s to 1E-11m 2 In this embodiment, the first flow rate is set to 6.40E-11m 2 / s. The circulation flow rate can have an error of -20% to +20% relative to the set value. To minimize variations in the probability of particle presence, the trigger is preferably within an error of -10% to +10% relative to the set value. When the control device 90 sets the circulation flow rate to the first flow rate, the process ends.

[0066] If the ink viscosity is greater than 3 mPa·s in step S40 (S40: YES), the control device 90 proceeds to step S52 and determines that the ink viscosity is a second viscosity greater than the first viscosity. The ink containing particles having an average particle size of the first particle size and a viscosity of the second viscosity is also referred to as the fourth liquid.

[0067] In step S62, in order to set the probability of particle existence in the fourth liquid having a second viscosity higher than the first viscosity of the first liquid to 60% or more, the control device 90 controls the operation of the circulation mechanism 94 so that the circulation flow rate of the fourth liquid becomes a fourth flow rate larger than the first flow rate of the first liquid. In this embodiment, the fourth flow rate is 1.50E-10m 2 When the control device 90 sets the circulation flow rate to the fourth flow rate, this process ends.

[0068] In step S20, if the average particle size is greater than 6 μm (S20: Yes), the control device 90 proceeds to step S32 and determines that the ink particle size is a second particle size greater than the first particle size. In step S42, the control device 90 compares the obtained ink viscosity with a predetermined threshold. In this embodiment, the predetermined threshold in step S42 is set to 3 mPa·s, similar to step S40. The threshold in step S42 may also be set to a different value than that in step S40.

[0069] If the ink viscosity is 3 mPa·s or less (S42: No), the control device 90 proceeds to step S54 and determines the ink viscosity to be the third viscosity. The third viscosity can be any viscosity less than the fourth viscosity; for example, it can be equal to the first viscosity. An ink containing particles having an average particle size of the second particle size and a viscosity of the third viscosity is also referred to as a second liquid.

[0070] In step S64, the control device 90 sets the circulation flow rate of the second liquid to the second flow rate. In this embodiment, the second flow rate is 1.80E-11m 2 / s. Because the second liquid has a second particle size that is larger than the first particle size of the particles contained in the first liquid, the second flow rate is set to a circulation flow rate that is smaller than the first flow rate in order to achieve a particle presence probability of 60% or greater. Furthermore, in the liquid ejection device 100 of this embodiment, when the second liquid is supplied at the first flow rate, the particle presence probability in the nozzle Nz indicates less than 60%. When the control device 90 sets the second liquid circulation flow rate, this process ends.

[0071] If the ink viscosity is greater than 3 mPa·s in step S42 (S42: YES), the control device 90 proceeds to step S56 and determines that the ink viscosity is a fourth viscosity that is higher than the third viscosity. The fourth viscosity can be any viscosity greater than the third viscosity and, for example, can be equal to the second viscosity. An ink containing particles having an average particle size of the second particle size and a viscosity of the fourth viscosity is also referred to as a fifth liquid.

[0072] In step S66, the control device 90 sets the circulation flow rate of the fifth liquid to the fifth flow rate. In this embodiment, the fifth flow rate is 7.70E-11m 2 / s. Because the fifth liquid has a fourth viscosity that is higher than the third viscosity of the second liquid, the fifth flow rate is set to a fifth flow rate that is greater than the second flow rate of the second liquid in order to set the particle presence probability to 60% or higher. When the control device 90 sets the circulation flow rate of the fifth liquid, this process ends.

[0073] As described above, according to the liquid ejection device 100 of this embodiment, when a second liquid containing particles having a second particle size larger than the first particle size of the particles contained in the first liquid is supplied to the liquid ejection head 1, the control device 90 controls the circulation mechanism 94 so that the circulation flow rate becomes a second flow rate that is smaller than the first flow rate. The liquid ejection device 100 of this embodiment can compensate for the reduced probability of particle presence in nozzles Nz due to the increased particle size by reducing the circulation flow rate. Therefore, even when inks having different particle sizes are supplied to the liquid ejection head 1, the circulation flow rate can be adjusted to the particle size of the particles contained in the ink, thereby suppressing the thickening of the ink while reducing or minimizing the occurrence of adverse phenomena such as reduced ink performance due to the reduced probability of particle presence.

[0074] According to the liquid ejection device 100 of this embodiment, when a fifth liquid containing particles having an average particle size of the second particle size and having a fourth viscosity higher than the third viscosity of the second liquid is supplied to the liquid ejection head 1, the control device 90 controls the circulation mechanism 94 so that the circulation flow rate reaches the fifth flow rate, which is greater than the second flow rate. In the liquid ejection device 100 of this embodiment, a margin is provided to increase the circulation flow rate by only an amount corresponding to the increased probability of particle presence due to the increased viscosity. Therefore, when supplying ink with a high viscosity, the occurrence of adverse effects such as reduced ink performance due to a decreased probability of particle presence can be reduced, while further increasing the circulation flow rate can further reduce ink thickening.

[0075] According to the liquid ejection device 100 of this embodiment, when a fourth liquid containing particles having an average particle size of a first particle size and having a second viscosity higher than the first viscosity of the first liquid is supplied to the liquid ejection head 1, the control device 90 controls the circulation mechanism 94 so that the circulation flow rate becomes a fourth flow rate greater than the first flow rate. In the liquid ejection device 100 of this embodiment, the probability of particles existing in the nozzle Nz can be further increased due to the smaller particle size and higher viscosity. Therefore, a margin is provided to increase the circulation flow rate only by an amount corresponding to the increased probability of particles existing due to the smaller particle size and higher viscosity. Therefore, when an ink with a smaller particle size and higher viscosity is supplied, it is possible to suppress degradation of the ink's performance while further suppressing thickening by circulating the ink.

[0076] According to the liquid ejection device 100 of this embodiment, all of the multiple types of liquids, including the first liquid and the second liquid, stored in the liquid container 93 can be supplied to a single liquid ejection head 1. Therefore, even when multiple types of ink are supplied, the liquid ejection device 100 of this embodiment can suppress the thickening of the ink according to the type of ink while suppressing the degradation of the ink performance.

[0077] According to the liquid ejection device 100 of this embodiment, when the first liquid is supplied to the liquid ejection head at a first flow rate, the probability of particles existing in nozzle Nz is greater than 60%. When the second liquid is supplied to the liquid ejection head at a second flow rate, the probability of particles existing in nozzle Nz is greater than 60%. Therefore, the liquid ejection device 100 of this embodiment can reduce or suppress the degradation of the performance of the first and second liquids as inks.

[0078] B. Other implementation methods:

[0079] (B1) Figure 11 : is an explanatory diagram showing parameter settings of the liquid ejection device 100 according to another embodiment 1. The viscosity VC is 1 mPa·s, the ejection amount VA is 3E-12m 2 / s. Figure 11 In FIG. 1 , the setting value of the circulation flow rate required to set the probability of particle existence in the nozzle Nz to 60% or more is shown for each particle size PS of the particles contained in the ink. Figure 11 As shown, in the liquid ejection device 100 of this embodiment, the circulation flow rate is set to decrease as the particle size PS of the supplied ink increases. Thus, even when inks having different particle sizes PS are supplied, the circulation mechanism 94 can be controlled so as to achieve a circulation flow rate corresponding to each particle size PS, thereby setting the probability of particles existing in the nozzle Nz to 60% or more. In addition, Figures 11 to 16 The circulation flow rates shown are not limited to the values ​​shown in the drawings; they may be within a range of -20% to +20% of the values ​​shown. To minimize variations in the probability of particle presence in nozzle Nz, the circulation flow rate is preferably smaller than the range of -10% to +10%.

[0080] In the first embodiment described above, the first flow rate is shown as the circulation flow rate for the case of having the first particle size, for example, 6.40E-11m 2 / s, and the second flow rate as the circulation flow rate in the case of having a second particle size larger than the first particle size is, for example, 1.80E-11m 2 In contrast, for example, Figure 11 As shown, the control device 90 may further control the circulation mechanism 94 so that the circulation flow rate of the third liquid becomes a third flow rate smaller than the second flow rate when a third liquid containing particles having a third particle size PS whose average value is larger than the second particle size is supplied to the liquid ejection head 1. The third particle size is, for example, 13 μm, and the third flow rate is, for example, 7.30E-12 m 2 / s.

[0081] The liquid ejection device 100 of this embodiment can adjust the circulation flow rate corresponding to each liquid, even when supplying multiple types of liquids having different particle sizes PS, such as three or more types of particle sizes, to the liquid ejection head 1. Therefore, even when supplying inks having three or more different particle sizes, it is possible to circulate the ink to suppress thickening while also suppressing degradation in ink performance.

[0082] (B2) In the first embodiment described above, an example is shown in which, after confirming the particle size in step S20, the ink viscosity is confirmed in step S40 or step S42. This illustrates a method of confirming liquid parameters in the order of particle size and viscosity. Alternatively, the liquid ejection device 100 may confirm the particle size after confirming the viscosity.

[0083] Figure 12 : is an explanatory diagram showing parameter settings of the liquid ejection device 100 according to another embodiment 2. The particle size PS is 5 μm, the ejection amount VA is 3E-12 m 2 / s. Figure 12 In FIG. 1 , the setting value of the circulation flow rate required to set the probability of particle presence in the nozzle Nz to 60% or more is shown for each viscosity VC of the ink. Figure 12As shown, in the liquid ejection device 100 of this embodiment, the circulation flow rate is set to increase as the viscosity VC of the supplied ink increases. Thus, even when inks having different viscosities VC are supplied, the circulation mechanism 94 can be controlled to achieve a circulation flow rate corresponding to each viscosity VC, thereby maintaining a particle presence probability of 60% or greater in the nozzle Nz.

[0084] In the liquid ejection device 100 of this embodiment, the control device 90 controls the circulation mechanism 94 so that the circulation flow rate is the first flow rate when ink having a first viscosity is supplied to the liquid ejection head 1. Specifically, the first viscosity is, for example, 1 mPa·s, and the first flow rate is, for example, 6.40E-11. Furthermore, when a fourth liquid having a second viscosity greater than the first viscosity is supplied to the liquid ejection head 1, the control device 90 controls the circulation mechanism 94 so that the circulation flow rate is a fourth flow rate greater than the first flow rate. The second viscosity is 4 mPa·s, and the fourth flow rate is 1.50E-10.

[0085] According to this embodiment of the liquid ejection device 100, for example, even when supplied with multiple types of liquids having different viscosities, the circulation flow rate can be adjusted to correspond to each viscosity. Therefore, even when supplied with inks having different viscosities, it is possible to suppress ink thickening while also preventing degradation in ink performance. In the liquid ejection device 100 of this embodiment, the circulation flow rate is increased only by an amount corresponding to the increased probability of particle presence due to increased viscosity. Therefore, when supplied with inks having higher viscosities, it is possible to further suppress ink thickening while also preventing degradation in ink performance.

[0086] In the liquid ejection device 100 of this embodiment, the control device 90 further controls the circulation mechanism 94 so that the circulation flow rate of the sixth liquid becomes an eighth flow rate that is greater than the fourth flow rate when the sixth liquid having a fifth viscosity greater than the second viscosity is supplied to the liquid ejection head 1. For example, if the fifth viscosity is 40 mPa·s and the eighth flow rate is 9.80E-9 m 2 / s.

[0087] The liquid ejection device 100 of this embodiment can adjust the circulation flow rate to correspond to each of a plurality of liquids having different viscosities VC, such as three or more different viscosities. Therefore, even when inks having three or more different viscosities are supplied to the liquid ejection head 1, it is possible to circulate the ink to suppress thickening while also suppressing degradation of the ink's performance.

[0088] (B3) Figure 13: is an explanatory diagram showing parameter settings of the liquid ejection device 100 according to another embodiment 3. The particle size PS is 8 μm, the ejection amount VA is 3E-12 m 2 / s. Figure 13 In the figure, the setting value of the circulation flow rate required to set the probability of particle existence in the nozzle Nz to 60% or more is shown for each viscosity VC of the ink. In the first embodiment described above, the following example is shown, that is, when the average particle size is the second particle size, the control device 90 controls the circulation mechanism 94 in such a manner that the circulation flow rate is set to the second flow rate when the viscosity VC is a predetermined threshold value of 3 mPa·s or less, and to the fifth flow rate that is greater than the second flow rate when the viscosity VC is greater than 3 mPa·s. On the other hand, it is also possible to Figure 13 As shown, for example, when the viscosity VC of the supplied ink is greater than 3 mPa·s and less than 10 mPa·s, the circulation flow rate is controlled to be the fifth flow rate. Furthermore, when ink having a viscosity VC greater than 10 mPa·s is supplied, the circulation flow rate corresponding to each range of each viscosity VC is set, for example, such as 10 to 20 mPa·s and 20 to 30 mPa·s.

[0089] (B4) In the first embodiment described above, the ejection amount is shown to be 3E-12m 2 In contrast, the liquid ejection device 100 may also adjust the circulation flow rate according to the ejection amount.

[0090] Figure 14 : is an explanatory diagram showing parameter settings of the liquid ejection device 100 according to another embodiment 4. The particle size PS is 5 μm and the viscosity VC is 1 mPa·s. Figure 14 , for each ejection volume VA of ink ejected from nozzle Nz, the set value of the circulation flow rate required to achieve a particle presence probability of 60% or greater in nozzle Nz is shown. Specifically, the circulation flow rate is set to increase as the ejection volume VA ejected from nozzle Nz increases. Thus, even when the ejection volume VA ejected from nozzle Nz is varied, the circulation mechanism 94 can be controlled to achieve a circulation flow rate corresponding to each ejection volume VA, thereby maintaining a particle presence probability of 60% or greater in nozzle Nz.

[0091] The control device 90 may also be Figure 10 After the particle size PS is confirmed in step S20, the ejection volume VA of the first liquid per unit time is confirmed. When the ejection volume VA is the first ejection volume, the circulation mechanism 94 can be controlled so that the circulation flow rate of the first liquid becomes the first flow rate. Specifically, the first ejection volume is 3E-12m2 / s, the first flow rate is 6.40E-11m 2 / s. In addition, after the particle size PS is confirmed in step S20, the ejection amount VA of the second liquid may be set to a second ejection amount greater than the first ejection amount. In this case, the circulation mechanism 94 may be controlled so that the circulation flow rate of the second liquid becomes a sixth flow rate greater than the first flow rate. Specifically, the second ejection amount is 3E-10m 2 / s, the sixth flow rate is 1.20E-9m 2 / s.

[0092] The liquid ejection device 100 of this embodiment can increase the circulation flow rate, further suppressing ink thickening. Furthermore, by increasing the ejection volume VA, the decrease in the probability of particle presence that may occur with an increase in the circulation flow rate can be compensated. Therefore, by suppressing the decrease in the probability of particle presence at nozzle Nz, thereby suppressing the degradation of ink performance, the circulation volume can be increased, thereby more reliably reducing or suppressing the occurrence of ink thickening.

[0093] The control device 90 may also be Figure 10 After the viscosity VC is confirmed in step S20, the magnitude of the ink ejection volume VA per unit time is confirmed. For example, after executing step S20, the control device 90 may control the circulation mechanism 94 so that the circulation flow rate becomes the first flow rate when the ink ejection volume VA is set to the first ejection volume, and control the circulation mechanism 94 so that the circulation flow rate becomes the sixth flow rate that is greater than the first flow rate when the ejection volume VA is set to the second ejection volume greater than the first ejection volume. Specifically, the second ejection volume is 3E-10m 2 / s, the sixth flow rate is 1.20E-9m 2 According to the liquid ejection device 100 of this embodiment, by increasing the circulation flow rate only by an amount corresponding to the increased probability of particle existence caused by the increase in the ejection volume, the circulation volume can be increased while suppressing a decrease in the performance of the first liquid, thereby more reliably reducing or suppressing the occurrence of ink thickening.

[0094] Figure 15 : is a second explanatory diagram showing parameter settings of the liquid ejection device 100 according to another embodiment 4. The particle size PS is 8 μm, and the viscosity VC is 1 mPa·s. Figure 15 , for each discharge volume VA, shows the set value of the circulation flow rate required to achieve a particle presence probability of 60% or greater in the nozzle Nz. Specifically, the circulation flow rate is set to increase as the discharge volume VA increases. The liquid discharge device 100 can also control the circulation mechanism 94 so that the circulation flow rate corresponds to the discharge volume VA.

[0095] The control device 90 may also determine whether the discharge amount is greater than a predetermined threshold value in step S42 after executing step S20. For example, in step S42, when the discharge amount VA of the second liquid is set to the third discharge amount, the circulation mechanism 94 is controlled in such a manner that the circulation flow rate becomes the second flow rate. In addition, when the discharge amount VA of the second liquid is set to the fourth discharge amount greater than the third discharge amount, the circulation mechanism 94 may also be controlled in such a manner that the circulation flow rate becomes the seventh flow rate greater than the second flow rate. Specifically, the third discharge amount is 3E-12, and the fourth discharge amount is 3E-10. Although the third discharge amount is equal to the first discharge amount described above, and the fourth discharge amount is equal to the second discharge amount described above, it can also be set to any discharge amount other than the first discharge amount or the second discharge amount.

[0096] According to this embodiment of the liquid ejection device 100, by increasing the circulation flow rate of the second liquid, the thickening of the second liquid can be suppressed. Furthermore, by increasing the ejection volume VA, the decrease in the probability of particle presence associated with the increase in the circulation flow rate can be compensated. Therefore, while suppressing the degradation of the performance of the second liquid, the thickening of the second liquid can be more reliably prevented or suppressed.

[0097] (B5) In the first embodiment described above, the method of confirming the ink viscosity in step S40 or S42 after confirming the particle size in step S20 is shown as an example. In other words, the liquid parameters are confirmed in the order of particle size and viscosity. Alternatively, the liquid ejection device 100 can set the circulation flow rate after confirming the viscosity and ejection volume in that order. Even for a fourth liquid having a different viscosity from the first liquid, the liquid ejection device 100 can control the circulation mechanism 94 so that the circulation flow rate corresponds to the ejection volume VA at which the probability of particle presence is 60% or greater.

[0098] Figure 16 : is an explanatory diagram showing parameter settings of the liquid ejection device 100 according to another embodiment 5. The particle size PS is 5 μm and the viscosity VC is 4 mPa·s. Figure 16 , for each discharge volume VA, shows the set value of the circulation flow rate required to achieve a particle presence probability of 60% or greater in nozzle Nz. Specifically, the circulation flow rate is set to increase as the discharge volume VA increases. The liquid discharge device 100 can also control the circulation mechanism 94 to achieve a circulation flow rate corresponding to the discharge volume VA.

[0099] In the liquid ejection device 100 of this embodiment, when the fourth liquid having a viscosity VC greater than the first viscosity, i.e., a second viscosity, is supplied to the liquid ejection head 1, the circulation mechanism 94 is controlled so that the circulation flow rate of the fourth liquid becomes the fourth flow rate when the ejection volume VA of the fourth liquid is set to the fifth ejection volume. When the ejection volume VA of the fourth liquid is set to the sixth ejection volume greater than the fifth ejection volume, the circulation mechanism 94 is controlled so that the circulation flow rate of the fourth liquid becomes the ninth flow rate greater than the fourth flow rate. Specifically, the fourth flow rate is 1.50E-10m 2 / s, the ninth flow rate is 5.60E-9m 2 / s. The fifth discharge amount is 3E-12, and the sixth discharge amount is 3E-10. Although the fifth discharge amount is equal to the first discharge amount and the sixth discharge amount is equal to the second discharge amount, they can also be set to any discharge amount other than the first discharge amount or the second discharge amount.

[0100] According to this embodiment of the liquid ejection device 100, the control device 90 controls the circulation mechanism 94 to increase the circulation flow rate when the ejection volume of the fourth liquid, which has a second viscosity greater than the first viscosity, increases. This increase in ejection volume VA can compensate for the potential decrease in particle presence probability associated with an increase in the circulation flow rate. Thus, the circulation volume of the fourth liquid can be increased while suppressing degradation in the performance of the fourth liquid, thereby more reliably preventing or suppressing thickening.

[0101] (B6) In the first embodiment described above, one nozzle Nz and nozzle flow channel RN are provided with one pressure chamber CB1 connected via the supply flow channel RR1, one piezoelectric element PZ1 corresponding to the pressure chamber CB1, one pressure chamber CB2 connected via the discharge flow channel RR2, and one piezoelectric element PZ2 corresponding to the pressure chamber CB2. Alternatively, one nozzle Nz and nozzle flow channel RN may be provided with four pressure chambers, and four piezoelectric elements corresponding to each pressure chamber. For example, one nozzle Nz and nozzle flow channel RN may be provided with two pressure chambers CB1 connected via two supply flow channels RR1, two piezoelectric elements PZ1 corresponding to each pressure chamber CB1, two pressure chambers CB2 connected to the nozzle flow channel RN via two discharge flow channels RR2, and two piezoelectric elements PZ2 corresponding to each pressure chamber CB2.

[0102] (B7) In the first embodiment described above, an example is shown in which the circulation mechanism 94 supplies a plurality of types of liquids stored in the liquid container 93 to a single liquid ejection head 1. In contrast, the liquid ejection device 100 may also include, for example, a plurality of liquid ejection heads, each of which includes a first liquid ejection head having the same structure as the liquid ejection head 1 described in the first embodiment, and a second liquid ejection head also having the same structure as the liquid ejection head 1. In this case, the circulation mechanism 94 may, for example, supply the first liquid to the first liquid ejection head and supply the second liquid to the second liquid ejection head. According to the liquid ejection device 100 of this embodiment, since a different liquid ejection head can be used for each type of ink, it is easier to switch the conditions of the circulation flow rate or ejection amount for each type of ink than in a method in which a plurality of types of liquids are supplied to a single liquid ejection head.

[0103] C. Other methods:

[0104] The present disclosure is not limited to the above-mentioned embodiments and can be implemented in various ways without departing from its main purpose. For example, the present disclosure can be implemented even in the following ways. In order to solve part or all of the problems of the present disclosure, or to achieve part or all of the effects of the present disclosure, the technical features in the above-mentioned embodiments corresponding to the technical features in the various methods described below can be appropriately replaced or combined. In addition, if the technical feature is not described as necessary content in this specification, it can be appropriately deleted.

[0105] (1) According to one embodiment of the present disclosure, a liquid ejection device is provided, comprising: a liquid ejection head for ejecting a liquid containing particles; a circulation mechanism for adjusting the flow rate of the liquid circulating in the liquid ejection head; and a control device for controlling the operation of the circulation mechanism. In the liquid ejection device, the liquid ejection head comprises: a pressure chamber for applying pressure to the liquid; a supply flow path connected to the pressure chamber; a nozzle flow path connected to the supply flow path; a nozzle provided on the nozzle flow path and ejecting the liquid by the pressure applied by the pressure chamber; and a discharge flow path connected to the opposite side of the nozzle flow path from the nozzle. When a first liquid containing particles having an average particle size of a first particle size is supplied to the liquid ejection head, the control device controls the circulation mechanism so that the circulation flow rate of the first liquid in the supply flow channel, the nozzle flow channel, and the discharge flow channel becomes a first flow rate. When a second liquid containing particles having an average particle size of a second particle size larger than the first particle size is supplied to the liquid ejection head, the control device controls the circulation mechanism so that the circulation flow rate of the second liquid becomes a second flow rate smaller than the first flow rate. According to this method, the liquid ejection device can compensate for the probability of particle existence that may be reduced due to an increase in particle size by reducing the circulation flow rate. Therefore, even when inks having different particle sizes are supplied to the liquid ejection head, the circulation flow rate of the ink can be adjusted to correspond to the particle size, thereby suppressing the thickening of the ink and suppressing the degradation of the ink's performance.

[0106] (2) In the liquid ejection device of the above-described embodiment, the control device may further control the circulation mechanism so that the circulation flow rate of the third liquid becomes a third flow rate that is smaller than the second flow rate when a third liquid containing particles having a third particle size whose average particle size is larger than the second particle size is supplied to the liquid ejection head. According to the liquid ejection device of this embodiment, even when liquid having three different particle sizes is supplied, it is possible to suppress degradation of the performance of the liquid while suppressing thickening by circulating the liquid.

[0107] (3) In the liquid ejection device of the above-described embodiment, the control device may further control the circulation mechanism so that the circulation flow rate becomes a fourth flow rate greater than the first flow rate when a fourth liquid containing particles having an average particle size of the first particle size and having a second viscosity higher than the first viscosity of the first liquid is supplied to the liquid ejection head. According to the liquid ejection device of this embodiment, when a liquid having a small particle size and a high viscosity is supplied, it is possible to suppress degradation of the performance of the liquid while further suppressing thickening by circulating the liquid.

[0108] (4) In the liquid ejection device of the above-mentioned method, the following method may be adopted, that is, when a fifth liquid containing particles having an average particle size of the second particle size and having a fourth viscosity higher than the viscosity of the second liquid, i.e., the third viscosity, is supplied to the liquid ejection head, the control device controls the circulation mechanism so that the circulation flow rate becomes the fifth flow rate greater than the second flow rate. According to the liquid ejection device of this method, when a liquid with a high viscosity is supplied, the occurrence of an undesirable phenomenon in which the performance of the liquid is reduced due to a decrease in the probability of the presence of particles is reduced, and the thickening of the liquid can be further reduced by further increasing the circulation flow rate.

[0109] (5) In the liquid ejection device of the above-described embodiment, the control device may control the circulation mechanism so that the circulation flow rate of the first liquid becomes the first flow rate when the ejection amount per unit time of the first liquid is set to the first ejection amount, and control the circulation mechanism so that the circulation flow rate of the second liquid becomes a sixth flow rate greater than the first flow rate when the ejection amount of the second liquid is set to a second ejection amount greater than the first ejection amount. The liquid ejection device of this embodiment can increase the circulation amount while suppressing a decrease in the performance of the liquid by suppressing a decrease in the probability of the presence of particles, thereby more reliably reducing or suppressing the occurrence of liquid thickening.

[0110] (6) In the liquid ejection device of the above embodiment, the control device may control the circulation mechanism so that the circulation flow rate of the second liquid becomes the second flow rate when the ejection amount of the second liquid per unit time is set to the third ejection amount, and control the circulation mechanism so that the circulation flow rate becomes a seventh flow rate greater than the second flow rate when the ejection amount of the second liquid is set to a fourth ejection amount greater than the third ejection amount. According to the liquid ejection device of this embodiment, it is possible to more reliably prevent or suppress the occurrence of thickening of the second liquid while suppressing degradation of the performance of the second liquid.

[0111] (7) In the liquid ejection device of the above embodiment, a method may be adopted in which both the first liquid and the second liquid are supplied to a single liquid ejection head. According to this method, even when a plurality of types of liquids are supplied, the liquid ejection device can suppress the thickening of the liquid according to the type of the supplied liquid while suppressing the degradation of the performance of the liquid.

[0112] (8) In the liquid ejection device of the above-described embodiment, a plurality of liquid ejection heads including a first liquid ejection head and a second liquid ejection head may be provided, wherein the first liquid ejection head is supplied with the first liquid, and the second liquid ejection head is different from the first liquid ejection head and is supplied with the second liquid. According to this embodiment of the liquid ejection device, since a different liquid ejection head can be used for each type of liquid, it is easier to switch the conditions of the circulation flow rate or ejection amount for each type of liquid than in an embodiment in which multiple types of liquid are supplied to a single liquid ejection head.

[0113] (9) In the liquid ejection device of the above embodiment, the following embodiment may be adopted: when the probability of existence of particles per unit volume of liquid is defined as the particle existence probability, when the first liquid is supplied to the liquid ejection head at the first flow rate, the particle existence probability of the first liquid in the nozzle is 60% or more, and when the second liquid is supplied to the liquid ejection head at the second flow rate, the particle existence probability of the second liquid in the nozzle is 60% or more. According to the liquid ejection device of this embodiment, it is possible to reduce or suppress the performance degradation of the first liquid and the second liquid.

[0114] (10) In the liquid ejection device of the above embodiment, the following embodiment may be adopted: when the second liquid is supplied to the liquid ejection head at the first flow rate, the probability of the particles of the second liquid existing in the nozzle is less than 60%. According to the liquid ejection device of this embodiment, it is possible to reduce or suppress the degradation of the performance of the second liquid.

[0115] (11) According to another embodiment of the present disclosure, a liquid ejection device is provided, comprising: a liquid ejection head that ejects a liquid containing particles; a circulation mechanism that adjusts the flow rate of the liquid circulating in the liquid ejection head; and a control device that controls the operation of the circulation mechanism. In the liquid ejection device, the liquid ejection head comprises: a pressure chamber for applying pressure to the liquid; a supply flow channel that communicates with the pressure chamber; a nozzle flow channel that communicates with the supply flow channel; a nozzle that is provided on the nozzle flow channel and ejects the liquid by the pressure applied by the pressure chamber; and a discharge flow channel that is connected to the opposite side of the nozzle flow channel from the nozzle. The control device controls the circulation mechanism so that the circulation flow rate of the first liquid in the nozzle flow channel becomes a first flow rate when a first liquid having a first viscosity is supplied to the liquid ejection head, and controls the circulation mechanism so that the circulation flow rate becomes a fourth flow rate that is greater than the first flow rate when a fourth liquid having a second viscosity that is greater than the first viscosity is supplied to the liquid ejection head. According to the liquid ejection device of this aspect, when a liquid having a relatively high viscosity is supplied, it is possible to further suppress thickening of the liquid and suppress degradation of the performance of the liquid.

[0116] (12) In the liquid ejection device of the above embodiment, the control device may further control the circulation mechanism so that the circulation flow rate of the sixth liquid becomes an eighth flow rate that is greater than the fourth flow rate when a sixth liquid having a fifth viscosity greater than the second viscosity is supplied to the liquid ejection head. According to this embodiment, even when liquids having three or more different viscosities are supplied to the liquid ejection head, it is possible to suppress degradation of the performance of the liquid while suppressing thickening by circulating the liquid.

[0117] (13) In the liquid ejection device of the above embodiment, the control device may control the circulation mechanism so that the circulation flow rate of the first liquid becomes the first flow rate when the ejection amount of the first liquid per unit time is set to a first ejection amount, and control the circulation mechanism so that the circulation flow rate of the first liquid becomes a sixth flow rate that is larger than the first flow rate when the ejection amount of the first liquid is set to a second ejection amount that is larger than the first ejection amount. According to this embodiment of the liquid ejection device, the circulation amount can be increased while suppressing a decrease in the performance of the first liquid, thereby more reliably reducing or suppressing the occurrence of ink thickening.

[0118] (14) In the liquid ejection device of the above-described embodiment, the control device may control the circulation mechanism so that the circulation flow rate of the fourth liquid becomes the fourth flow rate when the ejection amount per unit time of the fourth liquid is set to a fifth ejection amount, and control the circulation mechanism so that the circulation flow rate of the fourth liquid becomes a ninth flow rate that is larger than the fourth flow rate when the ejection amount of the fourth liquid is set to a sixth ejection amount that is larger than the fifth ejection amount. According to the liquid ejection device of this embodiment, the circulation amount of the fourth liquid can be increased while suppressing a decrease in the performance of the fourth liquid, thereby more reliably preventing or suppressing the occurrence of thickening.

[0119] (15) In the liquid ejection device of the above embodiment, a method may be adopted in which both the first liquid and the fourth liquid are supplied to a single liquid ejection head. According to this method, even when a plurality of types of liquids are supplied, the liquid can be prevented from thickening according to the type of the supplied liquid while suppressing a decrease in the performance of the liquid.

[0120] (16) In the liquid ejection device of the above-described embodiment, a plurality of liquid ejection heads may be provided, including a first liquid ejection head and a second liquid ejection head, wherein the first liquid ejection head is supplied with the first liquid, and the second liquid ejection head is different from the first liquid ejection head and is supplied with the fourth liquid. According to this embodiment of the liquid ejection device, since a different liquid ejection head can be used for each type of liquid, it is easier to switch the conditions of the circulation flow rate or ejection amount for each type of liquid than in a method in which multiple types of liquid are supplied to a single liquid ejection head.

[0121] (17) In the liquid ejection device of the above embodiment, when the probability of existence of particles per unit volume of the liquid is defined as the particle existence probability, when the first liquid is supplied to the liquid ejection head at the first flow rate, the particle existence probability of the first liquid in the nozzle is 60% or more, and when the fourth liquid is supplied to the liquid ejection head at the fourth flow rate, the particle existence probability of the fourth liquid in the nozzle is 60% or more. According to the liquid ejection device of this embodiment, it is possible to reduce or suppress the deterioration of the performance of the first liquid and the fourth liquid.

[0122] (18) In the liquid ejection device of the above embodiment, the following embodiment may be adopted: when the fourth liquid is supplied to the liquid ejection head at the first flow rate, the probability of the particles of the fourth liquid existing in the nozzle is less than 60%. According to the liquid ejection device of this embodiment, it is possible to reduce or suppress the degradation of the performance of the fourth liquid.

[0123] The present disclosure can also be implemented in various ways other than the liquid ejection device, for example, by a method for manufacturing or controlling a liquid ejection device, a computer program for implementing the control method, or a non-transitory recording medium recording the computer program.

[0124] The present disclosure is not limited to inkjet methods, but can also be applied to any liquid ejection device that ejects liquids other than ink and the liquid ejection heads used in these liquid ejection devices. For example, it can be applied to the following various liquid ejection devices and their liquid ejection heads.

[0125] (1) Image recording devices such as facsimile devices.

[0126] (2) A color material ejecting device used in the manufacture of color filters for image display devices such as liquid crystal displays.

[0127] (3) Electrode material discharge devices used for forming electrodes of organic EL (Electro Luminescence) displays, field emission displays (FED), and the like.

[0128] (4) A liquid ejecting device for ejecting a liquid containing biological organic matter used in biochip manufacturing.

[0129] (5) As a sample ejection device for precision pipettes.

[0130] (6) Lubricating oil spraying device.

[0131] (7) Resin liquid spraying device.

[0132] (8) A liquid spraying device that precisely sprays lubricating oil onto precision equipment such as clocks and cameras.

[0133] (9) A liquid discharge device that discharges a transparent resin liquid such as an ultraviolet curable resin liquid onto a substrate in order to form a microscopic hemispherical lens (optical lens) used in an optical communication element or the like.

[0134] (10) A liquid discharge device that discharges an acidic or alkaline etching liquid for etching a substrate or the like.

[0135] (11) A liquid ejecting device having a liquid consuming head for ejecting other arbitrary minute amounts of liquid droplets.

[0136] In addition, "droplets" refer to the state of liquid ejected from the liquid ejection device, and also include the state of tail-shaped objects pulled out in granular, tear-like, or thread-like forms. In addition, the "liquid" mentioned here only needs to be a material that can be consumed by the liquid ejection device. For example, "liquid" can be any material in the state of a substance in a liquid phase, and liquid materials with high or low viscosity, as well as liquid materials such as sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, and liquid metals (metal melts) are also included in the "liquid". In addition, not only liquids as a state of matter, but also liquids in which particles of functional materials composed of solid objects such as pigments or metal particles are dissolved, dispersed, or mixed in a solvent are also included in the "liquid". In addition, as representative examples of liquids, inks or liquid crystals as described in the above embodiments can be listed.

[0137] Explanation of symbols

[0138] 1…Liquid ejection head; 2…Connecting plate; 3…Pressure chamber substrate; 4…Vibrating plate; 5…Reservoir chamber forming substrate; 8…Wiring substrate; 50…Opening; 51…Inlet; 52…Discharge outlet; 60…Nozzle substrate; 61, 62…Plastic thin plate; 81…Drive circuit; 90…Control device; 91…Moving mechanism; 92…Conveying mechanism; 93…Liquid container; 94…Circulation mechanism; 100…Liquid ejection device; 810…Wiring; 921…Storage housing; 922…Endless belt; CB1, CB2, CBq…Pressure chamber; Com, C om1, Com2…driving signal; Ln…nozzle array; Nz…nozzle; PP…medium; PZ1, PZ2, PZq…piezoelectric element; RA1…common supply channel; RA2…common discharge channel; RB1…common supply channel; RB2…common discharge channel; RJ…circulation channel; RK1…connecting channel; RK2…connecting channel; RN…nozzle channel; RR1…supply channel; RR2…discharge channel; RX1…connecting channel; RX2…connecting channel; ZDq…lower electrode; ZMq…piezoelectric body; ZUq…upper electrode.

Claims

1. A liquid ejection device comprising: a liquid ejection head that ejects liquid containing particles; Circulation mechanism; A control device that controls the action of the circulation mechanism, The circulation mechanism adjusts the flow rate of the liquid circulating in the liquid ejecting head under the control of the control device. The liquid ejection head comprises: a pressure chamber for applying pressure to the liquid; a supply flow channel communicating with the pressure chamber; a nozzle flow channel, which is in communication with the supply flow channel; a nozzle disposed on the nozzle flow channel and ejecting the liquid by the pressure applied by the pressure chamber; a discharge flow channel connected to the opposite side of the nozzle flow channel passing through the nozzle, When a first liquid containing particles having an average particle size of a first particle size is supplied to the liquid ejection head, the control device controls the circulation mechanism so that a circulation flow rate of the first liquid in the supply flow path, the nozzle flow path, and the discharge flow path becomes a first flow rate. The control device controls the circulation mechanism so that the circulation flow rate of the second liquid becomes a second flow rate smaller than the first flow rate when a second liquid containing particles having a second particle size having an average particle size larger than the first particle size is supplied to the liquid ejection head.

2. The liquid ejection device according to claim 1, wherein The control device further controls the circulation mechanism so that the circulation flow rate of the third liquid becomes a third flow rate smaller than the second flow rate when a third liquid containing particles of a third particle size whose average particle size is larger than the second particle size is supplied to the liquid ejection head.

3. The liquid ejection device according to claim 1 or claim 2, wherein: The control device further controls the circulation mechanism in a manner that makes the circulation flow rate become a fourth flow rate greater than the first flow rate when a fourth liquid containing particles having an average particle size of the first particle size and having a second viscosity higher than the first viscosity of the first liquid is supplied to the liquid ejection head.

4. The liquid ejecting device according to claim 1, wherein The control device further controls the circulation mechanism in a manner that makes the circulation flow rate become a fifth flow rate greater than the second flow rate when a fifth liquid containing particles having an average particle size of the second particle size and having a fourth viscosity higher than the viscosity of the second liquid, i.e., the third viscosity, is supplied to the liquid ejection head.

5. The liquid ejecting device according to claim 1, wherein When the discharge amount of the first liquid per unit time is set to a first discharge amount, the control device controls the circulation mechanism so that the circulation flow rate of the first liquid becomes the first flow rate. When the discharge amount of the second liquid is set to a second discharge amount greater than the first discharge amount, the control device controls the circulation mechanism so that the circulation flow rate of the second liquid becomes a sixth flow rate greater than the first flow rate.

6. The liquid ejecting device according to claim 1, wherein When the discharge amount of the second liquid per unit time is set to a third discharge amount, the control device controls the circulation mechanism so that the circulation flow rate of the second liquid becomes the second flow rate. When the discharge amount of the second liquid is set to a fourth discharge amount that is larger than the third discharge amount, the control device controls the circulation mechanism so that the circulation flow rate becomes a seventh flow rate that is larger than the second flow rate.

7. The liquid ejecting device according to claim 1, wherein Both the first liquid and the second liquid are supplied to one of the liquid ejecting heads.

8. The liquid ejecting device according to claim 1, wherein The plurality of liquid ejecting heads are provided, including a first liquid ejecting head to which the first liquid is supplied, and a second liquid ejecting head which is different from the first liquid ejecting head and to which the second liquid is supplied.

9. The liquid ejecting device according to claim 1, wherein When the probability of a particle existing per unit volume of liquid is defined as the particle existence probability, When the first liquid is supplied to the liquid ejection head at the first flow rate, the probability of existence of the particles contained in the first liquid in the nozzle is 60% or more. When the second liquid is supplied to the liquid ejection head at the second flow rate, the probability of existence of the particles contained in the second liquid in the nozzle is 60% or more.

10. The liquid ejecting device according to claim 9, wherein When the second liquid is supplied to the liquid ejection head at the first flow rate, the probability of existence of the particles in the second liquid in the nozzle is less than 60%.

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