Liquid ejecting apparatus, maintenance method of liquid ejecting apparatus

Abstract

The present application provides liquid ejection device, liquid ejection device's maintenance method, can reduce the frequency of control can be heated to the heating mechanism of liquid.The printer (1) has: ink ejection part (15), ink is ejected from nozzle (24);Ink circulation path (80) is constituted by ink flow path (51) capable of supplying ink to ink ejection part (15) and ink return path (57) for making ink supplied to ink ejection part (15) back flow;Heating device (900) has temperature regulating module (904) arranged in ink circulation path (80), can be heated to the ink in temperature regulating module (904);And delivery pump (82) can make the ink in ink circulation path (80) flow, the printer (1) adjusts the flow of ink heated by heating device (900) in ink circulation path (80).

Description

Technical Field

[0001] This invention relates to liquid jetting devices such as printers, and methods for maintaining such devices. Background Technology

[0002] Conventionally, as shown in Patent Document 1, an inkjet printer, as an example of a liquid ejection device, is known to heat high-viscosity ink in the supply path to reduce its viscosity, thereby enabling ink ejection. This inkjet printer includes: a recording head for ejecting ink, an ink tank for storing ink, a supply path for supplying ink from the ink tank to the recording head, a temperature detection unit for detecting the temperature of the ink, and a supply path heating unit for heating the ink in the supply path, and a heating control unit for controlling the supply path heating unit based on the detection results of the temperature detection unit.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2003-127417

[0004] However, in the case of an inkjet printer, as described in Patent Document 1, where the temperature of the ink in the recording head is adjusted by controlling the supply path heating unit based on the detection results of the temperature detection unit, there is a technical problem that the temperature control of the supply path heating unit must be performed frequently. Summary of the Invention

[0005] A liquid injection device includes: a liquid injection section for injecting liquid from a nozzle; a circulation path comprising a supply path and a return path, wherein the supply path supplies the liquid to the liquid injection section and the return path returns the liquid supplied toward the liquid injection section; a heating mechanism having a temperature control module disposed in the circulation path, the heating mechanism heating the liquid within the temperature control module; a flow mechanism for flowing the liquid within the circulation path; a state detection section for detecting the state of the liquid within the liquid injection section; and a control section that drives and controls the flow mechanism based on the viscosity of the liquid within the liquid injection section, which is inferred from the detection result detected by the state detection section, to adjust the flow rate of the liquid heated by the heating mechanism within the circulation path.

[0006] A maintenance method for a liquid injection device, the liquid injection device comprising: a liquid injection section for injecting liquid from a nozzle; a circulation path consisting of a supply path and a return path, the supply path supplying the liquid to the liquid injection section and the return path causing the liquid supplied toward the liquid injection section to flow back; a heating mechanism having a temperature control module disposed in the circulation path, the heating mechanism heating the liquid within the temperature control module; and a flow mechanism for circulating the liquid within the circulation path, wherein the flow rate of the liquid heated by the heating mechanism in the circulation path is adjusted in the maintenance method of the liquid injection device. Attached Figure Description

[0007] Figure 1 This is a block diagram showing the structure of a liquid injection device.

[0008] Figure 2 This is an explanatory diagram schematically showing the liquid injection unit in a liquid injection device.

[0009] Figure 3 This is a diagram illustrating a computational model of simple harmonic motion assuming the residual vibration of the vibrating plate.

[0010] Figure 4 This is an explanatory diagram illustrating the relationship between the thickening of a liquid and the residual vibration waveform.

[0011] Figure 5 This is an explanatory diagram illustrating the relationship between the bubble and the residual vibration waveform.

[0012] Figure 6 This is a flowchart illustrating the maintenance method for a liquid injection device.

[0013] Figure 7 This is an explanatory diagram schematically showing the liquid injection unit in the liquid injection device according to Embodiment 2.

[0014] Figure 8 yes Figure 7 Sectional view along line 7-7 in the middle.

[0015] Explanation of reference numerals in the attached figures

[0016] 1. 501. Printer; 10. 510. Ink jet unit; 14. Transport section; 15. Ink jet section; 19. 519. Ink supply section; 24. Nozzle; 25. Nozzle face; 40. Irradiation section; 50. Ink cartridge; 51. 551. Ink flow path; 52. Holder; 53. Valve; 54. Supply pump; 55. Filter; 56. Pressure pump; 57. 557. Ink return path; 70. Sub-tank; 71. Liquid level sensor; 80. 580. Ink circulation path; 81. Filter 811. Upstream filter chamber; 812. Downstream filter chamber; 813. Filter; 82. Transfer pump; 821. Pump chamber; 822. Diaphragm; 823. Suction-side check valve; 824. Ejection-side check valve; 83. Damping section; 84. Head filter; 85. Common liquid chamber; 85A. Supply port; 86. Independent liquid chamber; 87. Vibrating plate; 88. Supply-side connection path; 89. Ejection element; 90. Reception chamber; 91. Discharge flow path on the discharge chamber side; 92. Discharge flow path on the common liquid chamber side. ; 93. Discharge chamber; 94. Discharge side connection path; 96A. Discharge chamber side outlet; 96B. Common chamber side outlet; 97A. Discharge chamber side return valve; 97B. Common chamber side return valve; 100. Degassing device; 101. Pressure reducing pump; 102. Degassing module; 111. Control unit; 112. Detector group; 113. Status detection unit; 115. Interface unit; 116. CPU; 117. Memory; 118. Control circuit; 119. Drive circuit; 120. Calculation Computer; 557A, Return path from the discharge chamber side; 557B, Return path from the common chamber side; 599, Ink temperature sensor; 900, 950, Heating device; 901, Warm water tank; 902, Warm water circulation pump; 903, 953, Heater; 904, Temperature control module; 905, Warm water circulation path; 906, Warm water temperature sensor; 956, Heater temperature sensor; 1101, Pressure sensor; 1102, Pressure reduction path; 1103, Degassing chamber; 1104, Pressure reduction chamber. Detailed Implementation

[0017] 1. Implementation Method 1

[0018] Hereinafter, an embodiment of the liquid jetting device and a method for maintaining the liquid jetting device will be described with reference to the accompanying drawings. The liquid jetting device is, for example, an inkjet printer that prints characters, photographs, and other images by jetting ink, which is a liquid, onto a medium such as printing paper.

[0019] Figure 1This is a block diagram showing the structure of a printer 1, which is a liquid jetting device according to Embodiment 1. A computer 120 outputs printing data corresponding to an image to the printer 1 in order to print the image. The printer 1 is a liquid jetting device that prints images on printing paper as a medium, and is connected to the computer 120 in a communicative manner.

[0020] Printer 1 includes an ink supply unit 19, a transport unit 14, an ink jetting unit 15 (which is a liquid jetting unit), an illumination unit 40, a detector group 112, and a control unit 111. The detector group 112 includes a status detection unit 113 capable of detecting the state of the ink within the ink jetting unit 15. Printer 1, receiving printing data from computer 120, controls the ink supply unit 19, transport unit 14, ink jetting unit 15, and illumination unit 40 via the control unit 111, and prints images on printing paper according to the printing data. The state within printer 1 is monitored by the detector group 112, which outputs the detection results to the control unit 111.

[0021] The control unit 111 includes an interface unit 115, a CPU 116, a memory 117, a control circuit 118, and a drive circuit 119. The interface unit 115 transmits and receives data between the computer 120 and the printer 1. The drive circuit 119 generates drive signals to drive the ejection elements 89 of the ink jetting unit 15.

[0022] CPU 116 is an arithmetic processing device. Memory 117 is a storage device that stores the program of CPU 116 or the working area, and has storage elements such as RAM and EEPROM. CPU 116 controls the ink supply unit 19, the conveying unit 14, the ink jetting unit 15, the irradiation unit 40, etc., according to the program stored in memory 117 through control circuit 118.

[0023] Figure 2An example of a liquid jetting unit provided in printer 1 is shown. The ink jetting unit 10, which is a liquid jetting unit, includes an ink jetting section 15 that jets ink from a nozzle 24 and an ink supply section 19. The ink supply section 19 is located between the ink cartridge 50, which serves as a liquid supply source in printer 1, and the ink jetting section 15. The ink supply unit 19 includes a holder 52 for mounting ink cartridges 50; an ink flow path 51 that supplies ink to the ink jetting unit 15; an ink return path 57 that forms a circulation path 80 with the ink flow path 51 to allow ink supplied to the ink jetting unit 15 to flow back; a valve 53 for opening and closing the ink flow path 51; a secondary tank 70 that serves as a liquid storage unit; a supply pump 54 that supplies ink from the ink cartridges 50 to the secondary tank 70; a filter 55 that filters the ink supplied to the secondary tank 70; a delivery pump 82 that serves as a flow mechanism; a heating device 900 that serves as a heating mechanism; a degassing device 100 that serves as a degassing mechanism; a filter 81; and a damping unit 83. The printer 1 of this embodiment includes multiple ink jetting units 10 corresponding to five inks: black ink, cyan ink, magenta ink, yellow ink, and white ink. The ink used in this embodiment is an ultraviolet-curable ink that is cured by irradiation with ultraviolet light. Figure 2 For illustration purposes, five liquid jetting units are shown as ink jetting units 10, 10b, 10c, 10d, and 10e.

[0024] The ink supply unit 19 includes a secondary reservoir 70 for storing ink in the ink flow path 51. The secondary reservoir 70 is connected to the ink flow path 51 so that ink can be supplied from the ink cartridge 50. The ink flow path 51 connects the secondary reservoir 70 to the supply port 85A of the ink jetting unit 15 in a manner that allows the ink stored in the secondary reservoir 70 to be supplied to the ink jetting unit 15. During printing, the internal space of the secondary reservoir 70 is open to the atmosphere. The liquid level of the ink stored in the secondary reservoir 70 is... Figure 2 The position shown in the gravity direction is below the nozzle surface 25 of the nozzle 24 of the ink ejection unit 15, and the atmospheric pressure applied to the liquid surface is adjusted to a pressure that will not disrupt the meniscus formed on the nozzle 24 as a gas-liquid interface, for example, adjusted to -1000Pa to -3500Pa using a gauge pressure gauge. Furthermore, when ink in the auxiliary tank 70 is consumed due to printing, the supply pump 54 is driven to replenish ink from the ink cartridge 50, thereby adjusting the position of the stored ink level. Alternatively, the auxiliary tank 70 can be connected to a pressure pump 56 in a manner that pressurizes the internal space, performing pressure cleaning by adjusting the pressure applied to the stored ink to a pressure that disrupts the meniscus of the nozzle 24, thus forcibly discharging the ink from the nozzle 24 of the ink ejection unit 15. It should be noted that a volume sensor 71 is provided in the auxiliary tank 70 to detect the amount of ink stored in the auxiliary tank 70.

[0025] The ink supply unit 19 includes an ink return path 57 that allows ink supplied to the ink jetting unit 15 to flow back to the ink flow path 51. The ink return path 57, together with the ink jetting unit 15, the auxiliary tank 70, and the ink flow path 51, forms an ink circulation path 80. In this embodiment, the ink return path 57 connects the common liquid chamber side outlet 96B of the ink jetting unit 15 and the auxiliary tank 70 such that ink discharged from the common liquid chamber side outlet 96B of the ink jetting unit 15 flows towards the ink flow path 51.

[0026] The ink supply unit 19 includes a delivery pump 82 that enables ink to flow within the ink circulation path 80. The delivery pump 82 is replaceably positioned in the ink flow path 51 between the auxiliary tank 70 and the ink jetting unit 15. Figure 2 As shown, the transfer pump 82 includes: a pump chamber 821; a suction-side flow path located on the auxiliary tank 70 side of the pump chamber 821, equipped with a suction-side check valve 823 that allows the flow of ink toward the pump chamber 821 and prevents the flow of ink toward the auxiliary tank 70; and an ejection-side flow path located on the ink ejection section 15 side of the pump chamber 821, equipped with an ejection-side check valve 824 that allows the flow of ink toward the ink ejection section 15 and prevents the flow of ink toward the pump chamber 821. The transfer pump 82 of this embodiment is a diaphragm pump classified as a positive displacement pump. This diaphragm pump transfers liquid by repeatedly performing a suction action that deforms the diaphragm 822, which is formed by a flexible member serving as a flexible wall, in the direction of increasing the volume of the pump chamber 821, and an ejection action that deforms the diaphragm 822 in the direction of decreasing the volume of the pump chamber 821.

[0027] The delivery pump 82 has two suction-side flow paths, two pump chambers 821, and two ejection-side flow paths. It is a two-phase type that reduces pressure fluctuations in the liquid delivery by staggering the phases of the repetitive actions, including suction and ejection, by 180 degrees. From the perspective of ensuring printing speed by supplying the amount of ink required for printing to the ink jetting section 15, the flow rate of the ink delivered by the delivery pump 82 is preferably 10 g / min or more. In this case, the lower limit flow rate during printing is 10 g / min. In addition, from the perspective of stabilizing the meniscus of the nozzle 24 formed in the ink jetting section 15, the upper limit flow rate of the ink is preferably 400 g / min or less. As the delivery pump 82, a tube pump, which is classified as a positive displacement pump, can also be used. This tube pump delivers liquid by deforming the flexible tube that forms part of the ink flow path 51, which is part of the pump chamber, using rollers.

[0028] The ink supply unit 19 includes a heating device 900 capable of heating the ink within the ink circulation path 80. There are no particular limitations on the heating mechanism as long as it can heat the ink, but the heating device 900 in this embodiment... Figure 2The diagram shows a temperature control module 904 located in the ink circulation path 80. The temperature control module 904 is positioned between the delivery pump 82 and the ink ejection section 15 in the ink flow path 51. The heating device 900 uses a warm water circulation pump 902 to circulate warm water from the warm water tank 901 between the temperature control module 904 and the warm water tank 901, thereby heating the ink within the temperature control module 904.

[0029] like Figure 2 As shown, the heating device 900 of this embodiment has five temperature control modules 904, 904b, 904c, 904d, and 904e, which are connected to the ink circulation paths 80, 80b, 80c, 80d, and 80e of the five ink jetting units 10, 10b, 10c, 10d, and 10e, and a warm water circulation path 905, which is connected to the warm water tank 901. A warm water temperature sensor 906, which serves as a detector group 112, is provided in the warm water circulation path 905. The control unit 111 controls the heater 903 of the warm water tank 901 based on the temperature of the warm water detected by the warm water temperature sensor 906, thereby adjusting the temperature of the ink in the five temperature control modules 904 to the set temperature.

[0030] The control unit 111 of printer 1 drives and controls the delivery pumps 82 of each ink circulation path 80 provided in the five ink ejection units 10. It adjusts the flow rate of ink in the ink circulation path 80 within the temperature control module 904 (heated to substantially the same temperature by the heating device 900) for each ink ejection unit 10, and adjusts the viscosity of the ink in the ink ejection section 15, estimated based on the detection results detected by each state detection unit 113, to a predetermined viscosity. In this embodiment, the predetermined viscosity of the ink in the ink ejection section 15 is 5 mPa·s to 15 mPa·s. Based on the temperature characteristics of the ink in this embodiment and the predetermined viscosity of the ink in the ink ejection section 15, the predetermined temperature of the ink in the ink ejection section 15 is more preferably 28°C to 45°C. In this case, the lower limit temperature of the ink in the ink ejection section 15 is 28°C.

[0031] The ink supply unit 19 includes a degassing device 100 capable of degassing the ink within the ink circulation path 80. There are no particular limitations on the degassing mechanism as long as it can degas the ink, but the degassing device 100 in this embodiment includes a degassing module 102 disposed in the ink circulation path 80. In this embodiment, the degassing module 102 is disposed between the temperature control module 904 and the ink ejection unit 15 in the ink flow path 51. Figure 2 As shown, the degassing module 102 is located downstream of the temperature control module 904 in the ink flow path 51, in the direction of ink flow. Therefore, the degassing device 100 can degas ink at higher temperatures, further improving degassing efficiency.

[0032] The degassing module 102 includes a degassing chamber 1103 for ink inflow and a depressurization chamber 1104 connected to the degassing chamber 1103 via a separation membrane that prevents liquids such as ink from passing through. A depressurization pump 101, acting as a vacuum adjustment mechanism, depressurizes the depressurization chamber 1104. When the depressurization chamber 1104 is depressurized, the vacuum level inside the chamber increases, thereby degassing the ink in the degassing chamber 1103 and reducing the amount of dissolved gas. The degassed ink in the degassing chamber 1103 then circulates in the ink circulation path 80, thereby suppressing the growth and generation of bubbles in the ink in the ink circulation path 80, including the ink jet section 15. In other words, the degassing device 100 increases the vacuum level of the degassing module 102 by depressurizing it, enabling degassing of the ink in the ink circulation path 80.

[0033] like Figure 2 As shown, the degassing device 100 of this embodiment has a depressurization path 1102 connecting the degassing modules 102, 102b, 102c, 102d, and 102e of the five ink jetting units 10, 10b, 10c, 10d, and 10e, respectively, to the depressurization pump 101. Furthermore, a pressure sensor 1101, serving as a detector group 112, is provided between the degassing modules 102, 102b, 102c, 102d, and 102e and the depressurization pump 101 in the depressurization path 1102. The control unit 111 controls the depressurization pump 101 based on the pressure value detected by the pressure sensor 1101, thereby adjusting the vacuum level of the degassing modules 102, 102b, 102c, 102d, and 102e.

[0034] The dissolved oxygen content of the ink in the ink circulation path 80, as an example of the amount of dissolved gas in the ink, is determined by the dissolved oxygen content of the ink previously contained in the ink cartridge 50 and the degassing capacity of the degassing device 100, specifically the capacity of the pressure-reducing pump 101 that adjusts the vacuum level within the degassing module 102. As ink is consumed, undegassed ink is sequentially replenished to the ink circulation path 80 starting from the auxiliary tank 70. Furthermore, during the process of supplying ink from the ink cartridge 50 to the ink circulation path 80 and during circulation, oxygen dissolves into the ink from the outside, slightly increasing the dissolved oxygen content of the ink. Additionally, the degassing capacity of the degassing device 100 varies depending on the flow rate of the ink flowing within the degassing module 102. For example, even if the vacuum level of the degassing module 102 is constant, decreasing the ink flow rate in the ink circulation path 80 reduces the dissolved oxygen content of the ink in the ink circulation path 80, while increasing the ink flow rate in the ink circulation path 80 increases the dissolved oxygen content of the ink in the ink circulation path 80.

[0035] In this case, a degassing device 100 is installed in the ink flow path 51, which forms part of the ink circulation path 80, located between the delivery pump 82 and the ink jetting unit 15. The control unit 111 controls the pressure reducing pump 101 to adjust the vacuum level of the degassing module 102, so that the dissolved oxygen content of the ink flowing into the degassing module 102 in the ink circulation path 80 is within a specified range. This allows ink with dissolved oxygen content adjusted to the specified range to be supplied to the ink jetting unit 15. Consequently, air bubbles trapped in the ink jetting unit 15 are reduced, and the ejection stability of ink from the ink jetting unit 15 is improved.

[0036] When the ink flow rate in the ink circulation path 80 is the same, increasing the vacuum level of the degassing module 102 reduces the dissolved oxygen content of the ink in the ink circulation path 80, while decreasing the vacuum level of the degassing module 102 increases the dissolved oxygen content of the ink in the ink circulation path 80. Therefore, at this flow rate, the vacuum level of the degassing module 102 required to supply ink with dissolved oxygen content at the upper limit of a specified range to the ink jetting unit 15 is the lower limit vacuum level.

[0037] The ink supply unit 19 includes a filter unit 81 for filtering foreign matter from the ink. For example... Figure 2 As shown, in this embodiment, the filter section 81 is replaceably disposed between the degassing module 102 and the ink jetting section 15 in the ink flow path 51. The filter section 81 consists of a filter 813, an upstream filter chamber 811 located on the auxiliary tank 70 side and a downstream filter chamber 812 located on the ink jetting section 15 side, which are divided by the filter 813. The filter section 81 is positioned above the nozzle surface 25 of the ink jetting section 15, with the upstream filter chamber 811 positioned above the downstream filter chamber 812 in the direction of gravity. Figure 2 As shown, when a head filter 84 is provided in the ink jet section 15, the filter particle size of the filter 813 is set to 5 μm, which is smaller than the filter particle size of the head filter 84, for example, 10 μm to 20 μm, and preferably the filter area is also set to be larger.

[0038] The ink supply unit 19 includes a damping unit 83 to reduce pressure fluctuations of the ink within the ink flow path 51. For example... Figure 2 As shown, in this embodiment, the damping part 83 is provided in a replaceable manner between the filter part 81 and the ink jetting part 15 in the ink flow path 51. The damping part 83 is located below the filter part 81 in the gravity direction and above the nozzle surface 25 of the ink jetting part 15.

[0039] Next, the ink ejection unit 15 in this embodiment will be described.

[0040] like Figure 2As shown, the ink jetting unit 15 has a supply port 85A that allows ink to flow into the ink jetting unit 15. The supply port 85A is connected to the ink flow path 51 in a manner that allows ink to be supplied to the ink jetting unit 15. The ink jetting unit 15 has a common liquid chamber 85 that communicates with the supply port 85A. The ink jetting unit 15 has a head filter 84 that filters the supplied ink. The head filter 84 captures air bubbles, foreign matter, etc., in the supplied ink. The head filter 84 is provided in the common liquid chamber 85 that communicates with the ink flow path 51.

[0041] The ink ejection unit 15 has multiple individual liquid chambers 86 communicating with a common liquid chamber 85. A nozzle 24 is provided corresponding to each individual liquid chamber 86. A portion of the wall of each individual liquid chamber 86 is formed by a vibrating plate 87. The common liquid chamber 85 and the multiple individual liquid chambers 86 are interconnected via a supply-side communication path 88. The multiple nozzles 24 communicate with the common liquid chamber 85 via their corresponding individual liquid chambers 86 and have openings in their nozzle faces 25.

[0042] The ink ejection unit 15 includes a plurality of ejection elements 89 and a plurality of receiving chambers 90 for accommodating the ejection elements 89. The receiving chambers 90 are located at positions different from the common liquid chamber 85. Each receiving chamber 90 accommodates one ejection element 89. The ejection element 89 is disposed on the surface of the vibrating plate 87 opposite to the portion facing the individual liquid chamber 86. The liquid ejection unit 15 is provided in the printer 1 such that by driving the ejection elements 89, the liquid in the individual liquid chamber 86 can be ejected as droplets from the plurality of nozzles 24.

[0043] In this embodiment, the ejection element 89 is composed of a piezoelectric element that contracts when a driving voltage is applied. If the vibrating plate 87 deforms after the ejection element 89 contracts due to the applied driving voltage, and then the driving voltage is released from the ejection element 89, the ink in the independent liquid chamber 86, whose volume has changed, is ejected from the nozzle 24 as droplets.

[0044] like Figure 2 As shown, the ink ejection unit 15 has a common liquid chamber side discharge port 96B, which allows the supplied ink to be discharged to the outside without passing through the nozzle 24. The ink ejection unit 15 has a common liquid chamber side discharge flow path 92 communicating with the common liquid chamber side discharge port 96B. Thus, the common liquid chamber 85 and the common liquid chamber side discharge flow path 92 of the ink ejection unit 15 constitute part of the ink circulation path 80.

[0045] Next, a method for inferring the state of the independent liquid chamber 86, which is the ink state, within the ink ejection unit 15 based on the detection results of the state detection unit 113 will be described. When a voltage is applied to the ejection element 89 according to a signal from the drive circuit 119, the vibrating plate 87 undergoes flexural deformation. As a result, a pressure fluctuation occurs within the independent liquid chamber 86. Due to this fluctuation, the vibrating plate 87 vibrates for a moment. This vibration is referred to as residual vibration. The state of the area including the independent liquid chamber 86 and the nozzle 24 communicating with the independent liquid chamber 86 can be inferred based on the state of this residual vibration.

[0046] Figure 3 This diagram illustrates a computational model of the simple harmonic motion of the residual vibration of the vibrating plate 87. If the drive circuit 119 applies a drive signal to the ejection element 89, the ejection element 89 expands and contracts accordingly with the voltage of the drive signal. The vibrating plate 87 flexes accordingly with the expansion and contraction of the ejection element 89. As a result, the volume of the independent liquid chamber 86 contracts after expanding. At this time, due to the pressure generated within the independent liquid chamber 86, a portion of the liquid filling the independent liquid chamber 86 is ejected from the nozzle 24 as ink droplets.

[0047] During the series of actions of the aforementioned vibrating plate 87, the vibrating plate 87 vibrates freely at its natural vibration frequency, which is determined by the shape of the ink flow path, the flow path resistance r based on the ink viscosity, the inertia m based on the weight of the ink within the flow path, and the compliance C of the vibrating plate 87. This free vibration of the vibrating plate 87 is residual vibration.

[0048] Figure 3 The calculation model for the residual vibration of the vibrating plate 87 shown is represented by pressure P, the aforementioned inertia m, compliance C, and flow path resistance r. If the calculation of volumetric velocity u is related to... Figure 3 The circuit is given a step response to pressure P, and the following equation is obtained.

[0049]

[0050]

[0051]

[0052] Figure 4 This is a diagram illustrating the relationship between ink viscosity and residual vibration waveform. Figure 4 The horizontal axis represents time t, and the vertical axis represents the magnitude of the residual vibration. Figure 4Em is the wave height of the first half-wave in the residual vibration waveform. For example, when the ink near nozzle 24 dries, the ink temperature in the ink ejection section 15 decreases, and the ink viscosity increases, i.e., thickens. If the ink viscosity increases, the flow path resistance r increases, and therefore, the vibration period and the attenuation of residual vibration increase.

[0053] Figure 5 This is an illustration of the relationship between the bubble and the residual vibration waveform. Figure 5 The horizontal axis represents time t, and the vertical axis represents the magnitude of the residual vibration. For example, if the bubble exists in either the ink in the independent liquid chamber 86 or the nozzle 24, the inertia m, which is the weight of the ink, and the volume of the bubble decrease accordingly compared to the normal state of the independent liquid chamber 86 and the nozzle 24. According to equation (2), if m decreases, the angular velocity ω increases, and therefore, the vibration period shortens. That is, the vibration frequency increases.

[0054] The frequency of the vibration waveform detected when air bubbles are present in the ink-filled independent liquid chamber 86 and nozzle 24 is higher than the frequency of the vibration waveform detected when air bubbles are absent in the ink-filled independent liquid chamber 86 and nozzle 24. Furthermore, the frequency of the vibration waveform detected when the independent liquid chamber 86 and nozzle 24 are filled with air is higher than the frequency of the vibration waveform detected when air bubbles are present in the ink-filled independent liquid chamber 86 and nozzle 24. Moreover, the larger the volume of any air bubble in the ink within the ink-filled independent liquid chamber 86 and nozzle 24, the higher the frequency of the vibration waveform.

[0055] On the other hand, consider, for example, when ink adheres to the nozzle surface 25, and the ink adhering to the nozzle surface 25 is connected to the ink in the nozzle 24, since the ink adhering to the nozzle surface 25 is connected to the ink filling the independent liquid chamber 86 via the nozzle 24, from the perspective of the vibrating plate 87, the amount of ink adhering to the nozzle surface 25 is increased compared to normal, thereby increasing the ink weight, i.e., the inertia m. Therefore, when the ink adhering to the nozzle surface 25 is connected to the ink in the independent liquid chamber 86, the frequency is lower than the normal frequency.

[0056] In addition, it is considered that if foreign matter such as paper dust adheres near the opening of nozzle 24, the amount of ink in the independent liquid chamber 86 and the amount of ink that seeps out, as seen from the vibrating plate 87, will increase compared to normal, thus increasing the inertia m. Furthermore, it is considered that the flow path resistance r is increased due to the fibers of the paper dust adhering near the outlet of nozzle 24. Therefore, when paper dust adheres near the opening of nozzle 24, the frequency decreases compared to normal spraying.

[0057] If ink thickening, air bubble ingress, or foreign matter adhesion occurs, the state within nozzle 24 and independent liquid chamber 86 becomes abnormal, and typically, ink stops being ejected from nozzle 24. This results in droplets appearing in the image recorded on the printed paper. Even when ink droplets are ejected from nozzle 24, there may be instances where the amount of droplets is small, or the droplets deviate from their flight direction and fail to land at the target location. Nozzles 24 that produce such ejection defects are called abnormal nozzles.

[0058] As described above, the residual vibration of the independent liquid chamber 86 connected to the abnormal nozzle is different from the residual vibration of the independent liquid chamber 86 connected to the normal nozzle 24. Therefore, the state detection unit 113 detects the vibration waveform of the independent liquid chamber 86. The control unit 111 estimates the state of the area including the independent liquid chamber 86 and the nozzle 24 connected to the independent liquid chamber 86 based on the detection result of the state detection unit 113.

[0059] The control unit 111 infers whether the state of the ink ejection unit 15 is normal or abnormal based on the vibration waveform of the independent liquid chamber 86, which is the detection result of the state detection unit 113. If the state within the independent liquid chamber 86 is abnormal, the control unit 111 infers whether the abnormality is due to the presence of air bubbles or to ink thickening. Based on the vibration waveform of the independent liquid chamber 86, the control unit 111 infers the total volume of air bubbles present in the independent liquid chamber 86 and the nozzle 24 communicating with it, as well as the degree of ink thickening in the independent liquid chamber 86 and the nozzle 24 communicating with it.

[0060] The control unit 111 can also infer whether the head filter 84 is functioning properly based on the detection results detected by the status detection unit 113. If the head filter 84 is clogged, the flow of ink through the head filter 84 is prone to stagnation. If the ink flow stagnates, air will enter from the nozzle 24 and easily accumulate in the independent liquid chamber 86. Therefore, the control unit 111 infers that the head filter 84 is malfunctioning based on the abnormality caused by the detected air bubbles in the independent liquid chamber 86.

[0061] Specifically, for example, when the control unit 111 detects an anomaly caused by air bubbles in more than a specified number of independent liquid chambers 86, it presumes that the head filter 84 is malfunctioning. The specified number is, for example, a number that cannot be addressed by supplementary printing, in which ink that should have been sprayed from the malfunctioning nozzle is replaced by ink sprayed from the surrounding nozzles 24.

[0062] The control unit 111 estimates the viscosity of the ink in the independent liquid chamber 86 within the ink ejection unit 15, based on the vibration waveform of the independent liquid chamber 86 detected by the state detection unit 113. For example, it compares the vibration waveform of the independent liquid chamber 86 detected by the state detection unit 113 when the viscosity of the ink in the independent liquid chamber 86 is within a specified viscosity range with the vibration waveform of the independent liquid chamber 86 as the detection result of the state detection unit 113, thereby estimating the viscosity of the ink in the independent liquid chamber 86 and determining whether the viscosity of the ink in the independent liquid chamber 86 is within the specified viscosity range, lower than the specified viscosity range, or higher than the specified viscosity range. Information related to the vibration waveform of the independent liquid chamber 86 detected by the state detection unit 113 when the viscosity of the ink in the independent liquid chamber 86 is within the specified viscosity range is stored in the memory 117 of the control unit 111. In addition, information related to the vibration waveform of the independent liquid chamber 86, which is the detection result detected by the state detection unit 113, and the viscosity of the ink in the independent liquid chamber 86 inferred from the detection result, along with the detection time, are stored as detection history in the memory 117 of the control unit 111.

[0063] The control unit 111 infers the degree of degassing of the ink in the ink ejection section 15 based on the vibration waveform of the independent liquid chamber 86, which is the detection result detected by the state detection unit 113. If bubbles are present in ink that has been degassed to a predetermined degree of degassing but has a low amount of dissolved gas, the volume of the bubbles decreases over time. Furthermore, it is difficult to generate bubbles from ink that has been degassed to a predetermined degree of degassing. Therefore, if the total volume of bubbles present in the independent liquid chamber 86, inferred from the vibration waveform of the independent liquid chamber 86 as the detection result detected by the state detection unit 113, is less than the total volume of bubbles present in the independent liquid chamber 86, inferred from the vibration waveform of the independent liquid chamber 86 detected before a predetermined time, the control unit 111 infers that the degree of degassing of the ink in the ink ejection section 15 is at the predetermined degree of degassing. If the total volume of bubbles present in the independent liquid chamber 86 is the same as or greater than the total volume of bubbles present in the independent liquid chamber 86, inferred from the vibration waveform of the independent liquid chamber 86 detected before a predetermined time, the control unit 111 infers that the degree of degassing of the ink in the ink ejection section 15 is lower than the predetermined degree of degassing.

[0064] Alternatively, if the total volume of bubbles present in the independent liquid chamber 86, as estimated based on the vibration waveform of the independent liquid chamber 86 (which is the detection result detected by the state detection unit 113), is the same as or smaller than a predetermined value, the control unit 111 estimates that the degassing degree of the ink in the ink ejection unit 15 is the same as or higher than a predetermined degassing degree; if it is higher than a predetermined value, the control unit 111 estimates that the degassing degree of the ink in the ink ejection unit 15 is lower than a predetermined degassing degree. The predetermined value is stored in the memory 117 of the control unit 111. Furthermore, the total volume of bubbles present in the independent liquid chamber 86, estimated based on the detection result detected by the state detection unit 113, and the degassing degree of the ink in the ink ejection unit 15, along with the detection time, are stored as a detection history in the memory 117 of the control unit 111.

[0065] In printer 1, when the temperature of the ink in the ink ejection section 15 becomes lower than a predetermined temperature, there is a situation where the viscosity of the ink in the ink ejection section 15 becomes higher than a predetermined viscosity, and ink is not ejected normally from the nozzle 24. Therefore, printer 1 is configured to perform a maintenance operation to adjust the viscosity of the ink. As a maintenance operation of printer 1, the control unit 111 of this embodiment drives the delivery pump 82 based on the viscosity of the ink in the ink ejection section 15, which is inferred from the detection results detected by the state detection unit 113, to adjust the flow rate of the ink heated by the heating device 900 in the ink circulation path 80, and adjust the viscosity of the ink in the ink ejection section 15 to a predetermined viscosity. In addition, as a maintenance operation of printer 1, the control unit 111 of this embodiment drives the corresponding delivery pump 82 based on the viscosity of the ink in each ink ejection section 15, which is inferred from the detection results detected by each state detection unit 113 of each of the five ink ejection units 10.

[0066] For example, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting section 15 is lower than a predetermined viscosity, as estimated by the detection results detected by the state detection unit 113, and the flow rate is set to a set flow rate, the control unit 111 drives the delivery pump 82 of that ink jetting unit 10 to make the flow rate less than the set flow rate. Alternatively, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting section 15 is a predetermined viscosity, as estimated by the detection results detected by the state detection unit 113, and the flow rate is set to a set flow rate, the control unit 111 drives the delivery pump 82 of that ink jetting unit 10 to maintain its flow rate. Furthermore, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting section 15 is higher than a predetermined viscosity, as estimated by the detection results detected by the state detection unit 113, and the flow rate of the ink in the ink jetting section 15 is set to a set flow rate, the control unit 111 drives the delivery pump 82 of that ink jetting unit 10 to make the flow rate greater than the set flow rate.

[0067] In addition, as a maintenance operation for printer 1, the control unit 111 of this embodiment drives and controls the heating device 900 based on the viscosity of the ink in each ink jet unit 15, which is inferred from the detection results detected by the state detection units 113 of each of the five ink jet units 10, the set flow rate when the detection results are detected, and the detection history related to the detection results stored in the memory 117 of the control unit 111.

[0068] For example, if the viscosity of the ink in the ink ejection section 15 of all ink ejection units 10 is lower than a specified viscosity, and the flow rate of the ink in the ink circulation path 80 is at the lower limit, as deduced from the detection result detected by the state detection unit 113, the control unit 111 drives the heating device 900 to make the temperature of the ink in the temperature control module 904 lower than the temperature of the ink in the temperature control module 904 when the detection result was detected. The lower limit flow rate is stored in the memory 117 of the control unit 111.

[0069] Additionally, for example, if the control unit 111 deduces, based on the detection results detected by the state detection unit 113, that the viscosity of the ink in the ink ejection sections 15 of all ink ejection units 10 is higher than a specified viscosity, and the flow rate of the ink in the ink circulation path 80 is at the upper limit flow rate, it drives the heating device 900 to make the temperature of the ink in the temperature control module 904 higher than the temperature of the ink in the temperature control module 904 when the detection results were detected. The upper limit flow rate is stored in the memory 117 of the control unit 111. Alternatively, for example, if the control unit 111 deduces, based on the detection results detected by the state detection unit 113, that the viscosity of the ink in the ink ejection sections 15 of all ink ejection units 10 is higher than a specified viscosity, but deduces that increasing the temperature of the ink in the temperature control module 904 would make the ink viscosity lower than the specified viscosity, it may also reduce the flow rate of the delivery pump 82 to the set flow rate when the detection results were detected, and drive the heating device 900 to make the temperature of the ink in the temperature control module 904 higher than the temperature of the ink in the temperature control module 904 when the detection results were detected.

[0070] In printer 1, when the deaeration degree of the ink in the ink ejection section 15 becomes lower than the specified deaeration degree, air bubbles are easily generated from the ink in the ink ejection section 15. Furthermore, these air bubbles tend to remain in the ink, sometimes preventing the ink from being ejected normally from the nozzle 24. Therefore, printer 1 is configured to perform a maintenance operation to adjust the deaeration degree of the ink. As a maintenance operation of printer 1, the control unit 111 of this embodiment controls the deaeration device 100 to ensure that the deaeration degree of the ink in the ink ejection section 15, as predicted by the status detection unit 113, is at the specified deaeration degree.

[0071] For example, if the degassing degree of the ink in the ink ejection section 15 of all ink ejection units 10, which is estimated based on the detection result detected by the state detection unit 113, is lower than the specified degassing degree, the control unit 111 drives the degassing device 100 to make the vacuum degree of the degassing module 102 higher than the vacuum degree of the degassing module 102 when the detection result is detected.

[0072] Additionally, for example, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting section 15 is higher than a predetermined viscosity, based on the detection results detected by the state detection unit 113, and the degassing degree of the ink in the ink jetting section 15 of all ink jetting units 10 is lower than a predetermined degassing degree, the control unit 111 drives the delivery pump 82 of the ink jetting unit 10 to make the flow rate higher than the predetermined flow rate, and drives the degassing device 100 to make the vacuum degree of the degassing module 102 higher than the vacuum degree of the degassing module 102 when the detection results are detected.

[0073] Furthermore, considering that even if the vacuum level of the degassing module 102 is constant, if the flow rate of ink in the ink circulation path 80 is reduced, the dissolved oxygen content of the ink in the ink circulation path 80 will decrease, and if the flow rate of ink in the ink circulation path 80 is increased, the dissolved oxygen content of the ink in the ink circulation path 80 will increase, the degassing device 100 can also be controlled so that the degassing degree of the ink in the ink ejection section 15, which is inferred from the detection results of the state detection unit 113, becomes a predetermined degassing degree.

[0074] For example, when the flow rate is set to a set flow rate and the degassing degree of the ink in the ink ejection sections 15 of all ink ejection units 10, as predicted by the detection results detected by the state detection unit 113, is lower than the specified degassing degree, and the delivery pump 82 is driven to maintain the set flow rate according to the detection results, the control unit 111 drives the degassing device 100 to make the vacuum degree of the degassing module 102 higher than the vacuum degree of the degassing module 102 when the detection results are detected. Furthermore, when the flow rate is set to a set flow rate and the degassing degree of the ink in the ink ejection sections 15 of all ink ejection units 10, as predicted by the detection results detected by the state detection unit 113, is lower than the specified degassing degree, and the delivery pump 82 is driven to make the flow rate higher than the set flow rate according to the detection results, the control unit 111 drives the degassing device 100 to make the vacuum degree of the degassing module 102 higher than the vacuum degree of the degassing module 102 when the detection results are detected.

[0075] In addition, when the flow rate is set to a set flow rate and the degassing degree of the ink in the ink ejection section 15 of all ink ejection units 10 is lower than the specified degassing degree based on the detection result detected by the state detection unit 113, and the delivery pump 82 is driven to make the flow rate less than the set flow rate according to the detection result, the degassing device 100 is driven to maintain the vacuum degree of the degassing module 102 when the detection result is detected.

[0076] Alternatively, the detection history related to the detection results can be considered. If, based on the current detection results, the degassing degree of the ink in the ink jet section 15 is lower than the specified degassing degree, and there is a previous detection history where the degassing degree of the ink in the ink jet section 15 is lower than the specified degassing degree, the degassing device 100 can be driven and controlled to make the vacuum degree of the degassing module 102 higher than the vacuum degree of the degassing module 102 when the detection result was detected. If, based on the current detection results, the degassing degree of the ink in the ink jet section 15 is lower than the specified degassing degree, and there is a detection history where the degassing degree of the ink in the ink jet section 15 is the same as or higher than the specified degassing degree, the flow rate of the delivery pump 82 can be lower than the set flow rate when the detection result was detected. For example, if the control unit 111 sets the flow rate to a set flow rate and, based on the detection results detected by the state detection unit 113, the viscosity of the ink in the ink ejection section 15 of all ink ejection units 10 is higher than the specified viscosity, and there is an ink ejection unit 10 whose degassing degree of the ink in the ink ejection section 15 is lower than the specified degassing degree based on the current detection results, and has a detection history where the degassing degree of the ink in the ink ejection section 15 is the same as or higher than the specified degassing degree based on the previous detection results, then the control unit 111 sets the flow rate of the delivery pump 82 of the ink ejection unit 10 to be lower than the set flow rate when the detection results were detected, and drives the heating device 900 to make the temperature of the ink in the temperature control module 904 higher than the temperature of the ink in the temperature control module 904 when the detection results were detected.

[0077] For example, during the printing process, among the multiple nozzles 24 in the ink ejection unit 15, there may be non-ejection nozzles that do not eject ink because they are not used for printing, and ejection nozzles that eject ink because they are used for printing. In this case, since ink is ejected from the nozzles 24 in both the ejection nozzles and the independent liquid chambers 86 connected to them, it is difficult for bubbles to be generated and for bubbles to grow in the ink, and the ink is difficult to thicken. In the non-ejection nozzles and the independent liquid chambers 86 connected to them, the ink stagnates because ink is not ejected from the nozzles 24. Therefore, compared to the independent liquid chambers 86 connected to the ejection nozzles, it is easier for bubbles to be generated and for bubbles to grow in the ink in the independent liquid chambers 86 connected to the non-ejection nozzles, and the ink is more likely to thicken. In the case where there are non-ejection nozzles that do not eject ink and ejection nozzles that eject ink among the multiple nozzles 24, the control unit 111 can also perform state detection by the state detection unit 113 targeting the independent liquid chambers 86 connected to the non-ejection nozzles.

[0078] Next, the maintenance method for printer 1 will be explained.

[0079] Figure 6 The maintenance routine in the maintenance method of the printer 1 shown can be executed when the printer 1 is started, or it can be repeated at specified intervals during the printing process of the printer 1.

[0080] During the initial maintenance procedure, the control unit 111 sets the set flow rate for driving the delivery pump 82 as the reference flow rate. The reference flow rate is stored in the memory 117 of the control unit 111. In this embodiment, the reference flow rate for driving the delivery pump 82 is the lower limit flow rate during printing. Additionally, the control unit 111 sets the set temperature of the ink in the temperature control module 904 for driving the heating device 900 as the reference temperature. The reference temperature is stored in the memory 117 of the control unit 111. In this embodiment, the reference temperature of the ink in the temperature control module 904 is the lower limit temperature of the ink in the ink jetting section 15 during printing. Furthermore, the control unit 111 sets the set vacuum level of the degassing module 102 for driving the degassing device 100 as the reference vacuum level. The reference vacuum level is stored in the memory 117 of the control unit 111. In this embodiment, the reference vacuum level of the degassing module 102 for driving the degassing device 100 is the lower limit vacuum level. Furthermore, if necessary, the control unit 111 sets the independent liquid chamber 86, which is the detection target of the status detection unit 113, to be an independent liquid chamber 86 connected to the non-jet nozzle when a non-jet nozzle is present, and sets it to be an independent liquid chamber 86 connected to the jet nozzle when a non-jet nozzle is absent. The settings of the above-mentioned set flow rate, set temperature, and set vacuum degree, together with the time when the settings were performed, are stored as a setting history in the memory 117 of the control unit 111.

[0081] The control unit 111 drives each mechanism based on set values. Specifically, the control unit 111 drives and controls the delivery pump 82 to adjust the ink flow rate within the ink circulation path 80 to a set flow rate. Additionally, the control unit 111 drives and controls the heating device 900 to adjust the ink temperature within the temperature control module 904 to a set temperature. Furthermore, the control unit 111 drives and controls the degassing device 100 to adjust the vacuum level of the degassing module 102 to a set vacuum level.

[0082] like Figure 6 As shown, in step S101, the control unit 111 determines whether a predetermined time has elapsed since the drive control of each mechanism was performed and adjusted to each set value. If the predetermined time has elapsed since the drive control of each mechanism was performed and adjusted to each set value, step S101 is "Yes". The control unit 111 then transfers the processing to step S102. If the predetermined time has not elapsed since the drive control of each mechanism was performed and adjusted to each set value, step S101 is "No", and the control unit 111 executes step S101 again. The control unit 111 repeatedly executes step S101 until step S101 becomes "Yes".

[0083] In step S102, the control unit 111 estimates the viscosity and degassing degree of the ink in the independent liquid chamber 86 of each ink ejection unit 15 as ink based on the detection results detected by the state detection units 113 of each of the five ink ejection units 10.

[0084] In step S103, the control unit 111 sets the flow rate of the delivery pump 82, the temperature of the ink in the temperature control module 904 when driving the heating device 900, and the vacuum degree of the degassing module 102 when driving the degassing device 100 for each ink ejection unit 10, based on the difference between the viscosity of the ink in each independent liquid chamber 86 estimated from the detection results and the specified viscosity, the difference between the degassing degree of the ink and the specified degassing degree, the set flow rate of the delivery pump 82 when the detection results are detected, the temperature of the ink in the temperature control module 904, the vacuum degree of the degassing module 102, and the detection history related to the detection results stored in the memory 117 of the control unit 111. It should be noted that each set adjustment amount is calculated in advance based on experimental results and stored in the memory 117 of the control unit 111.

[0085] For example, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting unit 15 is lower than the specified viscosity based on the detection result, the control unit 111 sets the flow rate of the delivery pump 82 in the ink jetting unit 10 to be lower than the set flow rate when the detection result is detected, within a range where the flow rate will not become less than the lower limit flow rate.

[0086] In addition, for example, if there is an ink jetting unit 10 in which the viscosity of the ink in the ink jetting unit 15 is estimated to be a predetermined viscosity based on the detection results, the control unit 111 maintains the flow rate setting of the delivery pump 82 in the ink jetting unit 10 at the set flow rate when the detection results are detected.

[0087] In addition, for example, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting unit 15 is higher than the specified viscosity based on the detection results, and the set flow rate when the detection results are detected is less than the upper limit flow rate, the control unit 111 sets the flow rate of the delivery pump 82 in the ink jetting unit 10 to be greater than the set flow rate when the detection results are detected, within a range not exceeding the upper limit flow rate.

[0088] Additionally, for example, if the viscosity of the ink in the ink ejection section 15 of all ink ejection units 10, as predicted by the detection results, is lower than the specified viscosity, and the set flow rate of the delivery pump 82 when the detection results are detected is the lower limit flow rate, the control unit 111 sets the temperature of the ink in the temperature control module 904 when driving the heating device 900 to be lower than the set temperature of the ink in the temperature control module 904 when the detection results are detected.

[0089] Furthermore, for example, if the control unit 111 determines, based on the detection results, that the viscosity of the ink in the ink ejection sections 15 of all ink ejection units 10 is higher than a specified viscosity, and the set flow rate of the delivery pump 82 when the detection results are detected is the upper limit flow rate, it sets the temperature of the ink in the temperature control module 904 when driving the heating device 900 to be higher than the set temperature of the ink in the temperature control module 904 when the detection results are detected. Alternatively, for example, if the control unit 111 determines, based on the detection results detected by the state detection unit 113, that the viscosity of the ink in the ink ejection sections 15 of all ink ejection units 10 is higher than a specified viscosity, but it determines that increasing the temperature of the ink in the temperature control module 904 would lower the viscosity of the ink, it may set the flow rate of the delivery pump 82 to be lower than the set flow rate when the detection results are detected, and set the temperature of the ink in the temperature control module 904 to be higher than the temperature of the ink in the temperature control module 904 when the detection results are detected.

[0090] Additionally, for example, if the control unit 111 sets the flow rate of the ink in the ink ejection section 15 of all ink ejection units 10 to a lower than the set flow rate based on the detection results detected by the state detection unit 113, and there are ink ejection units 10 whose degassing degree of the ink in the ink ejection section 15 is lower than the set degassing degree based on the current detection results, and has a detection history where the degassing degree of the ink in the ink ejection section 15 is the same as or higher than the set degassing degree based on the previous detection results, then the control unit 111 sets the flow rate of the delivery pump 82 of the ink ejection unit 10 to be lower than the set flow rate when the current detection results were detected, and sets the temperature of the ink in the temperature control module 904 to be higher than the set temperature of the ink in the temperature control module 904 when the current detection results were detected.

[0091] Additionally, for example, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting section 15 is higher than a specified viscosity, based on the detection result detected by the state detection unit 113, and the degassing degree of the ink in the ink jetting section 15 of all ink jetting units 10 is lower than a specified degassing degree, the control unit 111 sets the flow rate of the delivery pump 82 in the ink jetting unit 10 to be higher than the set flow rate when the detection result is detected, and sets the vacuum degree of the degassing module 102 when driving the degassing device 100 to be higher than the set vacuum degree of the degassing module 102 when the detection result is detected.

[0092] Furthermore, for example, if the control unit 111 sets the flow rate to a set flow rate, and based on the detection results detected by the state detection unit 113, the degassing degree of the ink in the ink ejection sections 15 of all ink ejection units 10 is lower than the specified degassing degree, and maintains the flow rate setting at the set flow rate based on the detection results, then the control unit 111 sets the vacuum level of the degassing module 102 when driving the degassing device 100 to a higher vacuum level than the vacuum level of the degassing module 102 when the detection results are detected. Additionally, if the control unit 111 sets the flow rate to a set flow rate, and based on the detection results detected by the state detection unit 113, the degassing degree of the ink in the ink ejection sections 15 of all ink ejection units 10 is lower than the specified degassing degree, and sets the flow rate to a higher than the set flow rate based on the detection results, then the control unit 111 sets the vacuum level of the degassing module 102 when driving the degassing device 100 to a higher vacuum level than the vacuum level of the degassing module 102 when the detection results are detected.

[0093] Furthermore, when the control unit 111 sets the flow rate to a set flow rate and, based on the detection results detected by the state detection unit 113, the degassing degree of the ink in the ink ejection section 15 of all ink ejection units 10 is lower than the specified degassing degree, and the flow rate is set to be less than the set flow rate based on the detection results, the vacuum degree setting of the degassing module 102 when driving the degassing device 100 is maintained at the set vacuum degree of the degassing module 102 when the detection results are detected.

[0094] The control unit 111 drives each mechanism to achieve its set values. When the control unit 111 executes the process of step S103, it temporarily terminates the maintenance process routine.

[0095] Control unit 111 executes Figure 6 The maintenance procedure shown adjusts the viscosity of the ink in the ink jetting unit 15 to a specified viscosity. Additionally, the control unit 111 executes... Figure 6 The maintenance procedure shown adjusts the degassing degree of the ink in the ink jet section 15 to the specified degassing degree.

[0096] For example, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting unit 15 is lower than the specified viscosity based on the detection result, the control unit 111 will make the flow rate of the delivery pump 82 in the ink jetting unit 10 lower than the set flow rate when the detection result is detected, within a range where the flow rate will not become less than the lower limit flow rate.

[0097] Additionally, for example, if there is an ink jetting unit 10 in which the viscosity of the ink in the ink jetting unit 15 is estimated to be a predetermined viscosity based on the detection results, the control unit 111 maintains the flow rate of the delivery pump 82 in the ink jetting unit 10 at the set flow rate when the detection results are detected.

[0098] Additionally, for example, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting unit 15 is higher than the specified viscosity based on the detection results, and the set flow rate when the detection results are detected is lower than the upper limit flow rate, the control unit 111 makes the flow rate of the delivery pump 82 in the ink jetting unit 10 higher than the set flow rate when the detection results are detected.

[0099] Additionally, for example, if the viscosity of the ink in the ink ejection section 15 of all ink ejection units 10, as predicted by the detection results, is lower than the specified viscosity, and the set flow rate of the delivery pump 82 when the detection results are detected is the lower limit flow rate, the control unit 111 makes the temperature of the ink in the temperature control module 904 lower than the temperature of the ink in the temperature control module 904 when the detection results are detected.

[0100] Additionally, for example, if the control unit 111 determines, based on the detection results, that the viscosity of the ink in the ink ejection sections 15 of all ink ejection units 10 is higher than a specified viscosity, and the set flow rate of the delivery pump 82 at the time the detection results are detected is the upper limit flow rate, it may raise the temperature of the ink in the temperature control module 904 to be higher than the temperature of the ink in the temperature control module 904 at the time the detection results are detected. Alternatively, for example, if the control unit 111 determines, based on the detection results detected by the state detection unit 113, that the viscosity of the ink in the ink ejection sections 15 of all ink ejection units 10 is higher than a specified viscosity, but it determines that increasing the temperature of the ink in the temperature control module 904 would lower the viscosity of the ink, it may also lower the flow rate of the delivery pump 82 compared to the set flow rate at the time the detection results are detected, and drive the heating device 900 to raise the temperature of the ink in the temperature control module 904 to be higher than the temperature of the ink in the temperature control module 904 at the time the detection results are detected.

[0101] Additionally, for example, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting section 15 is higher than a specified viscosity, based on the detection result detected by the state detection unit 113, and the degassing degree of the ink in the ink jetting section 15 of all ink jetting units 10 is lower than a specified degassing degree, the control unit 111 sets the flow rate of the delivery pump 82 in the ink jetting unit 10 to be higher than the set flow rate when the detection result is detected, and sets the vacuum degree of the degassing module 102 to be higher than the vacuum degree of the degassing module 102 when the detection result is detected.

[0102] Furthermore, for example, if the control unit 111 sets the flow rate to a set flow rate and, based on the detection results detected by the state detection unit 113, estimates that the degassing degree of the ink in the ink ejection sections 15 of all ink ejection units 10 is lower than the specified degassing degree, and maintains the flow rate setting at the set flow rate based on the detection results, then the control unit 111 sets the vacuum level of the degassing module 102 to be higher than the vacuum level of the degassing module 102 when the detection results are detected. Additionally, if the control unit 111 sets the flow rate to a set flow rate and, based on the detection results detected by the state detection unit 113, estimates that the degassing degree of the ink in the ink ejection sections 15 of all ink ejection units 10 is lower than the specified degassing degree, and sets the flow rate to be higher than the set flow rate based on the detection results, then the control unit 111 sets the vacuum level of the degassing module 102 to be higher than the vacuum level of the degassing module 102 when the detection results are detected.

[0103] Furthermore, when the flow rate is set to a set flow rate and the degassing degree of the ink in the ink ejection section 15 of all ink ejection units 10 is lower than the specified degassing degree based on the detection result detected by the state detection unit 113, and the flow rate is set to be less than the set flow rate based on the detection result, the control unit 111 maintains the vacuum degree of the degassing module 102 when driving the degassing device 100 is the same as the vacuum degree of the degassing module 102 when the detection result is detected.

[0104] Additionally, for example, if the control unit 111 sets the flow rate to a set flow rate and, based on the detection results detected by the state detection unit 113, the viscosity of the ink in the ink ejection section 15 of all ink ejection units 10 is higher than the specified viscosity, and there are ink ejection units 10 whose degassing degree of the ink in the ink ejection section 15 is lower than the specified degassing degree based on the current detection results, and which have a detection history where the degassing degree of the ink in the ink ejection section 15 is the same as or higher than the specified degassing degree based on the previous detection results, then the control unit 111 sets the flow rate of the delivery pump 82 of the ink ejection unit 10 to be lower than the set flow rate when the current detection results were detected, and sets the temperature of the ink in the temperature control module 904 to be higher than the temperature of the ink in the temperature control module 904 when the current detection results were detected.

[0105] In addition, the control unit 111 adjusts the viscosity of the ink in each ink ejection section 15 of the five ink ejection units 10 by simultaneously heating and adjusting the ink in each ink circulation path 80 of the five ink ejection units 10 and adjusting the flow rate of the ink in each ink circulation path 80 of the five ink ejection units 10.

[0106] As described above, the following effects can be obtained according to Embodiment 1.

[0107] Printer 1 includes: an ink ejection unit 15 that ejects ink from nozzles 24; an ink flow path 51 that supplies ink to the ink ejection unit 15; an ink return path 57 that forms an ink circulation path 80 with the ink flow path 51 in a manner that allows the ink supplied toward the ink ejection unit 15 to flow back; a heating device 900 that has a temperature control module 904 provided in the ink circulation path 80 and can heat the ink in the temperature control module 904; a delivery pump 82 that can flow the ink in the ink circulation path 80; a status detection unit 113 that can detect the status of the ink in the ink ejection unit 15; and a control unit 111 that drives and controls the delivery pump 82 based on the viscosity of the ink in the ink ejection unit 15, which is inferred from the detection result detected by the status detection unit 113, and adjusts the flow rate of the ink heated by the heating device 900 in the ink circulation path 80, thereby adjusting the viscosity of the ink in the ink ejection unit 15 to a predetermined viscosity.

[0108] In this way, by controlling the delivery pump 82 to adjust the flow rate of ink in the ink circulation path 80, the viscosity of the ink can be adjusted, thus reducing the control frequency of the heating device 900.

[0109] When the control unit 111 of printer 1 determines that the viscosity of the ink in the ink jet section 15 is higher than a predetermined viscosity based on a detection result detected by the status detection unit 113, it controls the delivery pump 82 to make the flow rate higher than the set flow rate at which the detection result was detected. In this way, by adjusting the flow rate of the ink in the ink circulation path 80 based on the detected viscosity of the ink in the ink jet section 15, the control frequency of the heating device 900 can be reduced.

[0110] When the control unit 111 of printer 1 determines, based on the detection result detected by the status detection unit 113, that the viscosity of the ink in the ink ejection unit 15 is higher than a specified viscosity and the flow rate is at the upper limit, it drives the heating device 900 to make the temperature of the ink in the temperature control module 904 higher than the temperature of the ink when the detection result was detected. In this way, by adjusting the flow rate using the delivery pump 82 and adjusting the ink temperature using the heating device 900, the viscosity of the ink can be adjusted.

[0111] The printer 1 also includes a degassing device 100, which has a degassing module 102 located in the ink circulation path 80. By increasing the vacuum level of the degassing module 102, the ink can be degassed. When the flow rate is set to a set flow rate, and the viscosity of the ink in the ink jet section 15, as predicted by the detection result detected by the state detection unit 113, is higher than a specified viscosity, and the degree of degassing of the ink in the ink jet section 15, as predicted by the detection result, is lower than a specified degree of degassing, the control unit 111 of the printer 1 sets the flow rate to be lower than the set flow rate at the time of the detection, and drives the heating device 900 to make the temperature of the ink in the temperature control module 904 higher than the temperature of the ink at the time of the detection. In this way, by adjusting the flow rate using the delivery pump 82 and adjusting the ink temperature using the heating device 900, the degree of degassing and the viscosity of the ink can be adjusted.

[0112] The printer 1 also includes a degassing device 100, which has a degassing module 102 located in the ink circulation path 80. By increasing the vacuum level of the degassing module 102, the ink can be degassed. When the flow rate is set to a set flow rate, and the viscosity of the ink in the ink jet section 15, as predicted by the detection result detected by the state detection unit 113, is higher than a specified viscosity, and the degree of degassing of the ink in the ink jet section 15, as predicted by the detection result, is lower than a specified degree of degassing, the control unit 111 of the printer 1 drives the delivery pump 82 to make the flow rate greater than the set flow rate at which the detection result was detected, and drives the degassing device 100 to make the vacuum level of the degassing module 102 higher than the vacuum level at which the detection result was detected. In this way, by adjusting the flow rate using the delivery pump 82 and adjusting the degree of ink degassing using the degassing device 100, the degree of ink degassing and the viscosity of the ink can be adjusted.

[0113] Printer 1 includes multiple ink jetting units 10, each ink jetting unit 10 having an ink jetting section 15, an ink circulation path 80, a delivery pump 82, and a status detection unit 113. A heating device 900 can simultaneously heat and adjust the ink within the temperature control modules 904 of each ink circulation path 80 of the multiple ink jetting units 10. A control unit 111, based on the viscosity of the ink in each ink jetting section 15 inferred from the detection results detected by the status detection units 113 of the multiple ink jetting units 10, drives and controls the corresponding delivery pump 82. In this way, even with multiple ink jetting sections 15 and multiple ink circulation paths 80 connected to the ink jetting sections 15, the viscosity of each ink can be adjusted without complex control of the heating device 900.

[0114] The ink ejection unit 15 of printer 1 has an independent liquid chamber 86 communicating with the nozzle 24 and an ejection element 89. The ejection element 89 can be driven to eject ink from the independent liquid chamber 86 through the nozzle 24. The state detection unit 113 detects the state of the ink within the ink ejection unit 15 by detecting the vibration of the independent liquid chamber 86 caused by the driving of the ejection element 89. In this way, the state of the independent liquid chamber 86 within the ink ejection unit 15, which is the state of the ink, can be detected using the ejection element 89 used to eject ink from the nozzle 24 without the need for additional detection elements.

[0115] The maintenance method for printer 1 is a maintenance method for a liquid jet device, which includes: an ink jetting unit 15 that jets ink from nozzles 24; an ink flow path 51 connected to the ink jetting unit 15 to supply ink to it; an ink return path 57 that forms an ink circulation path 80 with the ink flow path 51 to allow the ink supplied to the ink jetting unit 15 to flow back; a heating device 900 having a temperature control module 904 provided in the ink circulation path 80 for heating the ink within the temperature control module 904; and a delivery pump 82 for circulating ink within the ink circulation path 80. In this maintenance method, the viscosity of the ink in the ink jetting unit 15 is adjusted to a predetermined viscosity by adjusting the flow rate of the ink heated by the heating device 900 within the ink circulation path 80. Therefore, since the ink viscosity is adjusted by adjusting the flow rate of the ink within the ink circulation path 80, the control frequency of the heating device 900 can be reduced.

[0116] In the maintenance method of printer 1, if the viscosity of the ink in the ink jet section 15, where the flow rate is set to a set flow rate, is higher than a predetermined viscosity, the flow rate is increased by more than the set flow rate. In this way, by adjusting the ink flow rate based on the detected viscosity of the ink in the ink jet section 15, the control frequency of the heating device 900 can be reduced.

[0117] In the maintenance method of printer 1, when the viscosity of the ink in the ink jet section 15 is higher than the specified viscosity when the flow rate is set to the set flow rate, and the set flow rate is the upper limit flow rate, the temperature of the ink in the temperature control module 904 is made higher than the temperature of the ink in the temperature control module 904 when the flow rate is the set flow rate. In this way, the viscosity of the ink can be adjusted by adjusting the flow rate in the ink circulation path 80 and adjusting the ink temperature using the heating device 900.

[0118] The printer 1 also includes a degassing device 100, which has a degassing module 102 located in the ink circulation path 80. By increasing the vacuum level of the degassing module 102, the ink can be degassed. In the maintenance method of the printer 1, when the viscosity of the ink in the ink jet section 15 is higher than the specified viscosity and the degassing degree of the ink in the ink jet section 15 is lower than the specified degassing degree when the flow rate is set to a set flow rate, the flow rate is made lower than the set flow rate, and the temperature of the ink in the temperature control module 904 is made higher than the temperature of the ink in the temperature control module 904 when the flow rate is set to the set flow rate. In this way, by adjusting the flow rate in the ink circulation path 80 and adjusting the ink temperature using the heating device 900, the degassing degree and viscosity of the ink can be adjusted.

[0119] The printer 1 also includes a degassing device 100, which has a degassing module 102 located in the ink circulation path 80. By increasing the vacuum level of the degassing module 102, the ink can be degassed. In the maintenance method of the printer 1, when the viscosity of the ink in the ink jet section 15 is higher than a specified viscosity and the degassing degree of the ink in the ink jet section 15 is lower than a specified degassing degree when the flow rate is set to a set flow rate, the flow rate is increased compared to the set flow rate, and the vacuum level of the degassing module 102 is increased compared to the vacuum level of the degassing module 102 when the flow rate is set to the set flow rate. In this way, by adjusting the flow rate in the ink circulation path 80 and adjusting the degassing degree of the ink using the degassing device 100, it is possible to ensure the degassing degree of the ink while adjusting the viscosity of the ink.

[0120] Printer 1 includes multiple ink ejection units 10, each having an ink ejection section 15, an ink circulation path 80, and a delivery pump 82. The ink within the temperature control modules 904 of each ink circulation path 80 of the multiple ink ejection units 10 is heated and adjusted simultaneously. By adjusting the flow rate of the ink within each ink circulation path 80 of the multiple ink ejection units 10, the viscosity of the ink within each ink ejection section 15 of the multiple ink ejection units 10 is adjusted to a predetermined viscosity. In this way, even with multiple ink ejection sections 15 and multiple ink circulation paths 80 connected to the ink ejection sections 15, the viscosity of each ink can be adjusted without the need for complex control of the heating device 900.

[0121] 2. Implementation Method Two

[0122] Figure 7 An explanatory diagram illustrating the liquid jetting unit in the liquid jetting apparatus according to Embodiment 2 is provided. The ink jetting unit 510 in the printer 501 of this embodiment is a modification of the ink jetting section 15 and ink supply section 19 constituting the ink jetting unit 10 of Embodiment 1. Figure 7 This is achieved by showing the ink ejection unit 515 and the ink supply unit 519. It should be noted that the same reference numerals are used for the same components as in Embodiment 1, and repeated descriptions are omitted.

[0123] like Figure 7 , Figure 8As shown, the ink ejection unit 515 has a discharge chamber-side outlet 96A and a common chamber-side outlet 96B, which allow the supplied ink to be discharged to the outside without passing through the nozzle 24. The ink ejection unit 515 has a discharge chamber-side discharge flow path 91 communicating with the discharge chamber-side outlet 96A, a common chamber-side discharge flow path 92 communicating with the common chamber-side outlet 96B, and a discharge chamber 93 connecting the discharge chamber-side discharge flow path 91 and the independent chamber 86. Thus, the discharge chamber 93 communicates with the discharge chamber-side outlet 96A via the discharge chamber-side discharge flow path 91, and communicates with the supply port 85A via the independent chamber 86 and the common chamber 85. Furthermore, the common liquid chamber 85 is connected to the discharge outlet 96A of the discharge chamber side via the independent liquid chamber 86, the discharge chamber 93, and the discharge flow path 91 of the discharge chamber side, and is connected to the discharge outlet 96B of the common liquid chamber side via the discharge flow path 92 of the common liquid chamber side. The discharge chamber 93 is connected to multiple independent liquid chambers 86 via the discharge side connection path 94 provided for each independent liquid chamber 86.

[0124] like Figure 7 As shown, the ink ejection unit 515 includes an ink temperature sensor 599, which is a state detection unit capable of detecting the temperature of the ink within the ink ejection unit 515. In this embodiment, the ink temperature sensor 599 detects the temperature of the ink in the common liquid chamber 85, which is the ink state, within the ink ejection unit 515. The control unit 111 estimates the viscosity of the ink within the ink ejection unit 515 based on the relationship between the temperature of the ink within the ink ejection unit 515 (which is the detection result detected by the ink temperature sensor 599), the temperature of the ink stored in the memory 117, and the viscosity of the ink.

[0125] like Figure 7 As shown, the ink supply unit 519 of this embodiment includes: an ink return path 557 as a return flow path, and an ink circulation path 580 that forms a circulation flow path with the ink flow path 551 as a supply flow path; a delivery pump 582 as a flow mechanism; and a heating device 950 as a heating mechanism. The ink supply unit 519 of this embodiment is obtained by changing the ink flow path 51, ink circulation path 80, ink return path 57, delivery pump 82, and heating device 900 in the above embodiment to ink flow path 551, ink circulation path 580, ink return path 557, delivery pump 582, and heating device 950, and removing the degassing device 100.

[0126] The ink flow path 551 connects the auxiliary tank 70 and the supply port 85A of the ink jetting unit 515 in a manner that allows the ink stored in the auxiliary tank 70 to be supplied to the ink jetting unit 515. The ink flow path 551 of this embodiment does not include the delivery pump 82, which serves as a flow mechanism, as described in Embodiment 1. The ink return path 557 forms an ink circulation path 580 with the ink flow path 551 in a manner that allows the ink supplied to the ink jetting unit 515 to flow back.

[0127] Ink return path 557 has the ability to direct ink within ink circulation path 580 to... Figure 7 The delivery pump 582 flows in the direction of the arrow shown. The delivery pump 582 is located in the ink return path 557 between the auxiliary tank 70 and the ink ejection unit 515. The control unit 111 keeps the auxiliary tank 70 sealed and adjusts the ink flow rate within the ink circulation path 580 by driving the delivery pump 582.

[0128] like Figure 7 , Figure 8 As shown, in order to allow the ink supplied to the ink ejection unit 515 to flow back to the ink flow path 551, the ink return path 557 has a discharge chamber side return path 557A connected to the discharge chamber side outlet 96A and a common chamber side return path 557B connected to the common chamber side outlet 96B. In this embodiment, the ink return path 557 is configured to merge the discharge chamber side return path 557A and the common chamber side return path 557B.

[0129] A discharge chamber-side return valve 97A is provided on the discharge chamber-side return path 557A. A common chamber-side return valve 97B is provided on the common chamber-side return path 557B. The control unit 111 can switch between a mode in which the ink circulation path 580 is formed by the common chamber 85, independent chamber 86, discharge chamber 93, and discharge chamber-side discharge flow path 91 of the ink jetting unit 515 together with the discharge chamber-side return path 557A, and a mode in which the ink circulation path 580 is formed by the common chamber 85, common chamber-side discharge flow path 92, and common chamber-side return path 557B of the ink jetting unit 515. The control unit 111 can also open the return valve 97A on the discharge chamber side and drive the delivery pump 582 to increase the flow rate of ink in the ink circulation path 580, thereby circulating the ink in the ink circulation path 580 while moving a portion of the ink in the nozzle 24 into the independent liquid chamber 86, thereby suppressing the thickening of the ink in the nozzle 24.

[0130] like Figure 7As shown, the heating device 950 includes: a heater 953 capable of simultaneously heating the auxiliary tanks 70, 70b, 70c, 70d, and 70e located in the respective ink circulation paths 580, 580b, 580c, 580d, and 580e of the five ink ejection units 510; and a heater temperature sensor 956, which serves as a detector group 112, capable of detecting the temperature of the heater 953. In this embodiment, the auxiliary tanks 70, 70b, 70c, 70d, and 70e function as the temperature control modules 904, 904b, 904c, 904d, and 904e in the first embodiment described above. The control unit 111 controls the heater 953 based on the temperature detected by the heater temperature sensor 956, adjusting the temperature of the ink in the five auxiliary tanks 70 to the set temperature.

[0131] In printer 501, when the temperature of the ink in the ink ejection section 515 becomes lower than a predetermined temperature, there is a situation where the viscosity of the ink in the ink ejection section 515 becomes higher than a predetermined viscosity, and ink is not ejected normally from the nozzle 24. Therefore, printer 501 is configured to perform a maintenance operation to adjust the viscosity of the ink. As a maintenance operation of printer 501, the control unit 111 of this embodiment drives the delivery pump 582 to adjust the flow rate of the ink heated by the heating device 950 in the ink circulation path 580, and adjusts the viscosity of the ink in the ink ejection section 515, which is estimated based on the detection results detected by the ink temperature sensor 599, to a predetermined viscosity. In addition, as a maintenance operation of printer 501, the control unit 111 of this embodiment drives the corresponding delivery pump 582 based on the viscosity of the ink in each ink ejection section 515, which is estimated based on the detection results detected by each ink temperature sensor 599 of the plurality of ink ejection units 510.

[0132] For example, if the control unit 111 determines that the viscosity of the ink in the ink jet section 515, as estimated by the ink temperature sensor 599, is lower than a predetermined viscosity while maintaining a set flow rate, it controls the delivery pump 582 to reduce the flow rate below the set flow rate. Alternatively, if the control unit 111 determines that the viscosity of the ink in the ink jet section 515, as estimated by the ink temperature sensor 599, is a predetermined viscosity while maintaining a set flow rate, it controls the delivery pump 582 to maintain that flow rate. Furthermore, if the control unit 111 determines that the viscosity of the ink in the ink jet section 515, as estimated by the ink temperature sensor 599, is higher than a predetermined viscosity while maintaining a set flow rate within the ink circulation path 580, it controls the delivery pump 582 to increase the flow rate above the set flow rate.

[0133] Additionally, for example, if the control unit 111 determines, based on the detection result detected by the ink temperature sensor 599, that the viscosity of the ink in the ink ejection unit 515 is higher than the specified viscosity and the flow rate of the ink in the ink circulation path 580 is the upper limit flow rate, it drives the heating device 950 to make the temperature of the ink in the auxiliary tank 70, which is a temperature control module, higher than the temperature of the ink in the auxiliary tank 70 when the detection result was detected.

[0134] As described above, the following effects can be obtained according to Embodiment 2.

[0135] The printer 501 includes: an ink ejection unit 515 that ejects ink from nozzles 24; an ink flow path 551 that supplies ink to the ink ejection unit 515; an ink return path 557 that forms an ink circulation path 580 with the ink flow path 551 in a manner that allows the ink supplied toward the ink ejection unit 515 to flow back; a heating device 950 that has a sub-tank 70 provided in the ink circulation path 580 and can heat the ink in the sub-tank 70; a delivery pump 582 that can flow the ink in the ink circulation path 580; an ink temperature sensor 599 that can detect the state of the ink in the ink ejection unit 515; and a control unit 111 that drives and controls the delivery pump 582 based on the viscosity of the ink in the ink ejection unit 515, which is inferred from the detection result detected by the ink temperature sensor 599, to adjust the flow rate of the ink heated by the heating device 950 in the ink circulation path 580 and adjust the viscosity of the ink in the ink ejection unit 515 to a predetermined viscosity. In this way, by controlling the delivery pump 582 to adjust the flow rate of ink in the ink circulation path 580, the viscosity of the ink can be adjusted, thereby reducing the control frequency of the heating device 950.

[0136] When the control unit 111 of printer 501 determines, based on a detection result from ink temperature sensor 599, that the viscosity of the ink in ink jet section 515 is higher than a predetermined viscosity, and sets the flow rate to a set flow rate, it drives the delivery pump 582 to increase the flow rate beyond the set flow rate at which the detection result was detected. In this way, by adjusting the flow rate of ink in ink circulation path 580 based on the detected viscosity of ink in ink jet section 515, the control frequency of heating device 950 can be reduced.

[0137] When the control unit 111 of printer 501 determines, based on the detection result detected by ink temperature sensor 599, that the viscosity of the ink in ink jet unit 515 is higher than a specified viscosity and the flow rate is at the upper limit, it drives the heating device 950 to make the temperature of the ink in auxiliary tank 70 higher than the temperature of the ink when the detection result was detected. In this way, by adjusting the flow rate using delivery pump 582 and adjusting the ink temperature using heating device 950, the viscosity of the ink can be adjusted.

[0138] The printer 501 includes multiple ink ejection units 510, each ink ejection unit 510 having an ink ejection section 515, an ink circulation path 580, a delivery pump 582, and an ink temperature sensor 599. A heating device 950 can simultaneously heat and adjust the ink in the auxiliary tanks 70 of each ink circulation path 580 of the multiple ink ejection units 510. The control unit 111 drives and controls the corresponding delivery pump 582 based on the viscosity of the ink in each ink ejection section 515, which is inferred from the detection results detected by the ink temperature sensors 599 of the multiple ink ejection units 510. In this way, even with multiple ink ejection sections 515 and multiple ink circulation paths 580 connected to the ink ejection sections 515, the viscosity of each ink can be adjusted without complex control of the heating device 950.

[0139] The above-described embodiments and other embodiments described below can be combined with each other to implement the invention without technical inconsistencies. The other embodiments will be described below.

[0140] In one embodiment, the printer 1 may also have an ink jetting unit 10 corresponding to a type of ink.

[0141] When performing the maintenance procedure in the maintenance method for printer 1 for the first time, the reference flow rate for the set flow rate when the control unit 111 controls the drive flow rate of the delivery pump 82 can be any flow rate between the upper limit flow rate and the lower limit flow rate. Furthermore, the reference temperature for the set temperature of the ink in the temperature control module 904 set by the control unit 111 can be any temperature higher than the lower limit temperature of the ink in the ink jetting unit 15 during printing. Additionally, the reference vacuum level for the set vacuum level of the degassing module 102 when the control unit 111 controls the drive flow of the degassing device 100 can be any vacuum level lower than the lower limit vacuum level.

[0142] In step S103 of the maintenance process routine in the maintenance method of printer 1, the adjustment amount when the control unit 111 changes the flow rate setting of the delivery pump 82, the temperature setting of the ink in the temperature control module 904 when driving the heating device 900, and the vacuum setting of the degassing module 102 when driving the degassing device 100 can also be a preset fixed value. In this case, the control unit 111 repeatedly adjusts the set values ​​by driving the various mechanisms and predicts the state of the liquid in the ink jetting section 15, thereby adjusting the viscosity and degassing degree of the ink in the ink jetting section 15, which is in a liquid state, to the specified viscosity and specified degassing degree of the ink in the ink jetting section 15.

[0143] In the maintenance method of printer 1, if there is an ink jetting unit 10 where the viscosity of the ink in the ink jetting section 15 does not decrease or the temperature of the ink in the ink jetting section 15 does not rise even after repeated maintenance processes are performed to make the temperature of the ink in the temperature control module 904 higher than the set temperature and to make the ink circulate in the ink circulation path 80, the control unit 111 can also determine that the filter 813 of the filter section 81 of the ink jetting unit is clogged, and end the maintenance process, prompting the operator of printer 1 to replace the filter section 81.

[0144] In Embodiment 1, if the viscosity of the ink in the ink jet section 15 of the ink jet unit 10 is higher than a predetermined viscosity, as inferred from the detection result detected by the state detection unit 113, and it is deduced that a concave meniscus is formed in the nozzle 24 of the ink jet section 15, the control unit 111 of the printer 1 sets the flow rate of the delivery pump 82 of the ink jet unit 10 to exceed the upper limit flow rate, which is higher than the set flow rate when the detection result was detected. In this case, if it is deduced from the detection result detected by the state detection unit 113 that the meniscus of the nozzle 24 of the ink jet section 15 of the ink jet unit 10 is damaged, the control unit 111 sets the flow rate of the delivery pump 82 of the ink jet unit 10 to the upper limit flow rate and drives the heating device 900 to make the temperature of the ink in the temperature control module 904 higher than the temperature of the ink in the temperature control module 904 when the previous detection result was detected.

[0145] In Embodiment 1, the control unit 111 of the printer 1 may not infer the degree of degassing of the ink in the ink ejection section 15 based on the vibration waveform of the independent liquid chamber 86 detected by the status detection unit 113. In this case, for example, when the control unit 111 first executes the maintenance process routine in the printer 1 maintenance method, it sets the reference vacuum level, which is set as the set vacuum level of the degassing module 102, to the upper limit vacuum level when the degassing module 102 is depressurized at the maximum capacity of the pressure reducing pump 101. Alternatively, in this case, the control unit 111 may not infer the degree of degassing of the ink in the ink ejection section 15 or set the set vacuum level of the degassing mechanism in the maintenance process routine of the printer 1 maintenance method.

[0146] In one embodiment, an ink temperature sensor, which is a state detection unit, may be provided in the ink ejection section 15 of the printer 1 to detect the temperature of the ink within the ink ejection section 15. Then, the control unit 111 may infer the viscosity of the ink within the ink ejection section 15 based on the detection result detected by the ink temperature sensor, i.e., the temperature of the ink within the ink ejection section 15.

[0147] In one embodiment, a degassing sensor, which measures the dissolved oxygen content of the ink in the ink jetting section 15, may be provided in the ink jetting section 15 of the printer 1 as a state detection unit. Therefore, the control unit 111 can infer the degassing degree of the ink in the ink jetting section 15 based on the detection result detected by the degassing sensor, i.e., the dissolved oxygen content of the ink in the ink jetting section 15.

[0148] In Embodiment 1, the control unit 111 of the printer 1 may store the history of the amount of ink ejected from the nozzle 24 in the memory 117. In this case, if there are nozzles 24 with less ink ejection than a predetermined number of times and nozzles 24 with more ink ejection than a predetermined number of times, the independent liquid chamber 86 connected to the nozzle 24 with less ink ejection than a predetermined number of times may be detected by the status detection unit 113.

[0149] In embodiment one, it is also possible that, when the ink flows in the ink circulation path 80, the control unit 111 of the printer 1 communicates with an independent liquid chamber 86, for example, with an area where ink is difficult to flow in the common liquid chamber 85 of the ink ejection unit 15. Figure 2 The independent liquid chamber 86 at the right end of the middle is detected by the status detection unit 113.

[0150] In one embodiment, the control unit 111 of the printer 1 may detect multiple independent liquid chambers 86 through the status detection unit 113 without distinguishing between independent liquid chambers 86 connected to non-jet nozzles and independent liquid chambers 86 connected to jet nozzles.

[0151] In one embodiment, the ink ejection section 15 of the printer 1 may not have a common liquid chamber side outlet 96B. In this case, for example, the ink return path 57 may connect the portion of the ink flow path 51 located between the ink ejection section 15 and the damping section 83 and the auxiliary tank 70 in a manner that allows the ink supplied toward the ink ejection section 15 to flow back.

[0152] In one embodiment, the degassing module 102 of the degassing device 100 of printer 1 may be located in the ink return path 57.

[0153] In the second embodiment, the degassed ink may be pre-contained in the ink cartridge 50, and the control unit 111 supplies the degassed ink to the auxiliary tank 70 by driving and controlling the supply pump 54 and the delivery pump 582. The ink whose dissolved oxygen content is adjusted to a specified range is supplied to the ink ejection unit 515 by adjusting the dissolved oxygen content of the ink circulating in the ink circulation path 580 to a specified range.

[0154] The liquid jetting device may also include a carriage that mounts a liquid jetting section, from which liquid is jetted from the liquid jetting section mounted on the carriage that moves along the printing paper, which serves as the medium, to print an image on the printing paper. In this case, for example, in Embodiment 2, the auxiliary tank 70, filter 81, damping section 83, ink jetting section 515, delivery pump 582, and heating device 950 that constitute the ink circulation path 580 in the ink jetting unit 510 may be mounted on the carriage.

[0155] In the second embodiment, the damping part 83 of the printer 501 may also be a pressure reducing valve that has a damping function that can absorb pressure changes of the supplied ink.

[0156] The liquid ejection device may also include an electrothermal conversion element, such as a heater, capable of heating the ink in the independent liquid chamber as the ejection element of the ink ejection unit. For example, in Embodiment 1, the control unit 111 of the printer 1 may heat the ink in the independent liquid chamber 86 by driving the heater, which serves as the ejection element 89 of the ink ejection unit 15, causing it to produce film boiling, thereby ejecting the ink from the nozzle 24. In this case, the state detection unit may compare the highest temperature at which the ink is ejected, detected by the temperature detection element, which is part of the detector group 112 located directly below the heater, with a predetermined threshold, or infer the state within the independent liquid chamber 86 based on the difference in temperature change. Furthermore, an optical element-based fly detector may be included as part of the detector group 112, and the state detection unit may use the fly detector to detect the ejection state. The control unit 111 may also combine the state detection within the independent liquid chamber 86 with the detection results of the optical element-based fly detector to infer the state of the ink in the ink ejection unit 15.

Claims

1. A liquid injection device, characterized in that, have: Liquid injection section, which sprays liquid from a nozzle; The circulation path consists of a supply path and a return path. The supply path supplies the liquid to the liquid injection section, and the return path causes the liquid supplied toward the liquid injection section to flow back. The heating mechanism includes a temperature control module located in the circulation path, and the heating mechanism heats the liquid within the temperature control module; A flow mechanism that allows the liquid to flow within the circulation path; The state detection unit detects the state of the liquid within the liquid injection unit; as well as Control Department The control unit drives and controls the flow mechanism based on the viscosity of the liquid in the liquid injection section, which is inferred from the detection results detected by the state detection unit, to adjust the flow rate of the liquid heated by the heating unit in the circulation path. When the control unit deduces, based on the detection result detected by the state detection unit, that the viscosity of the liquid in the liquid injection unit is higher than the specified viscosity and the flow rate is the upper limit flow rate, it drives and controls the heating mechanism to make the temperature of the liquid in the temperature control module higher than the temperature of the liquid when the detection result was detected.

2. The liquid injection device according to claim 1, characterized in that, When the flow rate is a set flow rate, and the viscosity of the liquid in the liquid jet section is higher than a specified viscosity based on the detection result detected by the state detection unit, the control unit drives the flow mechanism to make the flow rate greater than the set flow rate when the detection result is detected.

3. The liquid injection device according to claim 1, characterized in that, The liquid injection device also includes a degassing mechanism, which has a degassing module located in the circulation path. The degassing mechanism degasses the liquid by increasing the vacuum level of the degassing module. When the flow rate is set, if the viscosity of the liquid in the liquid jet is higher than the specified viscosity and the degassing degree of the liquid in the liquid jet is lower than the specified degassing degree, based on the detection result detected by the state detection unit, the control unit sets the flow rate to be lower than the set flow rate when the detection result is detected, and drives the heating mechanism to make the temperature of the liquid in the temperature control module higher than the temperature of the liquid when the detection result is detected.

4. The liquid injection device according to claim 1, characterized in that, The liquid injection device also includes a degassing mechanism, which has a degassing module located in the circulation path. The degassing mechanism degasses the liquid by increasing the vacuum level of the degassing module. When the flow rate is a set flow rate, and the control unit deduces from the detection results detected by the state detection unit that the viscosity of the liquid in the liquid jet section is higher than the specified viscosity and the degassing degree of the liquid in the liquid jet section is lower than the specified degassing degree based on the detection results, the control unit drives the flow mechanism to make the flow rate greater than the set flow rate when the detection results are detected, and drives the degassing mechanism to make the vacuum degree of the degassing module higher than the vacuum degree when the detection results are detected.

5. The liquid injection device according to any one of claims 1 to 4, characterized in that, The liquid injection device includes multiple liquid injection units, each liquid injection unit comprising a liquid injection section, a circulation path, a flow mechanism, and a status detection section. The heating mechanism heats the liquids within the temperature control modules of each of the circulation paths of the plurality of liquid injection units simultaneously. The control unit drives and controls the corresponding flow mechanism based on the viscosity of the liquid in each liquid injection unit, which is inferred from the detection results detected by each of the state detection units of the plurality of liquid injection units.

6. The liquid injection device according to any one of claims 1 to 4, characterized in that, The liquid injection unit has an independent liquid chamber communicating with the nozzle and an ejection element. The liquid injection unit drives the ejection element to eject the liquid in the independent liquid chamber from the nozzle. The state detection unit detects the state of the liquid in the liquid jet unit by detecting the vibration of the independent liquid chamber caused by the driving of the ejection element.

7. A maintenance method for a liquid injection device, characterized in that, The liquid injection device includes: Liquid injection section, which sprays liquid from a nozzle; The circulation path consists of a supply path and a return path. The supply path supplies the liquid to the liquid injection section, and the return path causes the liquid supplied toward the liquid injection section to flow back. The heating mechanism includes a temperature control module located in the circulation path, and the heating mechanism heats the liquid within the temperature control module; as well as The flow mechanism causes the liquid to flow within the circulation path. In the maintenance method of the liquid injection device, the flow rate of the liquid heated by the heating mechanism in the circulation path is adjusted. In the maintenance method of the liquid injection device, when the viscosity of the liquid in the liquid injection section is higher than a specified viscosity when the flow rate is set to a set flow rate, and the set flow rate is the upper limit flow rate, the temperature of the liquid in the temperature control module is higher than the temperature of the liquid when the flow rate is set to the set flow rate.

8. The maintenance method for the liquid injection device according to claim 7, characterized in that, In the maintenance method of the liquid injection device, when the viscosity of the liquid in the liquid injection section is higher than the specified viscosity when the flow rate is set to a set flow rate, the flow rate is increased by more than the set flow rate.

9. The maintenance method for the liquid injection device according to claim 7, characterized in that, The liquid injection device also includes a degassing mechanism, which has a degassing module located in the circulation path. The degassing mechanism degasses the liquid by increasing the vacuum level of the degassing module. In the maintenance method of the liquid injection device, when the viscosity of the liquid in the liquid injection section is higher than the specified viscosity and the degassing degree of the liquid in the liquid injection section is lower than the specified degassing degree when the flow rate is set to a set flow rate, the flow rate is made lower than the set flow rate and the temperature of the liquid in the temperature control module is made higher than the temperature of the liquid when the flow rate is set to the set flow rate.

10. The maintenance method for the liquid injection device according to claim 7, characterized in that, The liquid injection device also includes a degassing mechanism, which has a degassing module located in the circulation path. The degassing mechanism degasses the liquid by increasing the vacuum level of the degassing module. In the maintenance method of the liquid injection device, when the viscosity of the liquid in the liquid injection section is higher than the specified viscosity and the degassing degree of the liquid in the liquid injection section is lower than the specified degassing degree when the flow rate is set to a set flow rate, the flow rate is increased by more than the set flow rate and the vacuum degree of the degassing module is increased by more than the vacuum degree when the flow rate is set to the set flow rate.

11. A method for maintaining a liquid injection device according to any one of claims 7 to 10, characterized in that, The liquid injection device includes multiple liquid injection units, each liquid injection unit comprising a liquid injection section, a circulation path, and a flow mechanism. In the maintenance method of the liquid injection device, The liquids within the temperature control modules of each of the circulating flow paths of the plurality of liquid injection units are heated simultaneously. The viscosity of the liquid in each of the liquid jet sections of the plurality of liquid jet units is adjusted to a predetermined viscosity by adjusting the flow rate of the liquid in each of the circulating flow paths of the plurality of liquid jet units.

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