Liquid ejection system and control method

Abstract

To provide a liquid ejection system head capable of reducing downtime for replacement by predicting the life of the liquid ejection head, and to provide a method of controlling a liquid ejection system.SOLUTION: A liquid discharge system includes a liquid discharge head including a piezoelectric element and configured to discharge liquid, and a life prediction unit configured to predict a life of the liquid discharge head based on a reference voltage of the piezoelectric element. Further, a control method for controlling a liquid discharge system including a liquid discharge head that includes a piezoelectric element and discharges a liquid includes acquiring a reference voltage of the piezoelectric element, and predicting a life of the liquid discharge head based on the reference voltage.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection system and a control method. [Background technology]

[0002] 2. Description of the Related Art In a liquid ejection apparatus such as an inkjet type liquid ejection apparatus, a drive signal is supplied to a piezoelectric element, thereby ejecting liquid such as ink from a liquid ejection head.

[0003] In Patent Document 1, the number of times liquid is ejected is counted, and the voltage value of the drive signal that drives the piezoelectric element is increased based on the counted number, thereby reducing the decrease in the displacement of the piezoelectric element that occurs due to deterioration over time and reducing the decrease in the amount of liquid ejected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-066948 Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, Patent Document 1 discloses a technique for reducing the decrease in ejection volume that occurs due to deterioration of the piezoelectric element over time by increasing the voltage value of the drive signal based on the count number. In other words, Patent Document 1 describes a technique for extending the life of the liquid ejection head.

[0006] However, while conventional methods predict deterioration over time, they do not predict the lifespan of the liquid ejection head. As a result, it is not possible to know how long the lifespan will be, and replacement or other measures are only carried out after the lifespan has expired, resulting in downtime. [Means for solving the problem]

[0007] A liquid ejection system according to a preferred aspect of the present invention includes a liquid ejection head having a piezoelectric element for ejecting liquid, and a life prediction unit for predicting the life of the liquid ejection head based on a reference voltage of the piezoelectric element.

[0008] A preferred aspect of the present invention provides a control method for controlling a liquid ejection system having a piezoelectric element and a liquid ejection head that ejects liquid, the control method including the steps of: acquiring a reference voltage of the piezoelectric element; and predicting the life of the liquid ejection head based on the reference voltage. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram illustrating the configuration of a liquid ejection system according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating an example of the configuration of the liquid ejection system shown in FIG. [Figure 3] 3 is a schematic diagram showing the function of the life extension processing unit in FIG. 2. FIG. [Figure 4] FIG. 3 is a cross-sectional view of a part of the head chip shown in FIG. [Figure 5] FIG. 5 is an enlarged view of the piezoelectric element shown in FIG. [Figure 6] FIG. 6 is a diagram showing the drive voltage and reference voltage applied to FIG. 5. [Figure 7] 6 is a diagram for explaining dielectric breakdown of the piezoelectric layer shown in FIG. 5. FIG. [Figure 8] FIG. 10 is a diagram showing the correspondence between the reference voltage and the failure rate included in the correspondence information. [Figure 9] 5 is a flowchart showing the processing of the liquid ejection system according to the first embodiment. [Figure 10] FIG. 10 is a schematic view illustrating the configuration of a liquid ejection system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the dimensions and scale of each part in the drawings may differ from the actual dimensions and some parts are shown schematically to facilitate understanding. Furthermore, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited thereto.

[0011] 1. First embodiment 1-1. Overview of the liquid ejection system 1 is a schematic diagram showing an example of the configuration of a liquid ejection system 1 according to a first embodiment. The liquid ejection system 1 is a system that performs printing using an inkjet method. In the example shown in FIG. 1, the liquid ejection system 1 includes a plurality of liquid ejection devices 100 and a server 300.

[0012] The plurality of liquid ejection devices 100 may have the same configuration as each other, or may have different configurations. Each liquid ejection device 100 is communicably connected to a server 300 via a communication network NW such as the Internet. For example, the server 300 is owned by a manufacturer that provides the liquid ejection device 100, and the liquid ejection device 100 is owned by a user who uses it.

[0013] Each liquid ejection device 100 is a liquid ejection device 100 that prints an image based on recording data DP onto a printing medium using an inkjet method. The printing medium is not particularly limited and may be, for example, various types of paper, cloth, or film. The recording data DP is image data in a format that can be processed by the liquid ejection device 100. For example, the recording data DP is generated by subjecting image data in a file format such as PostScript or PDF (Portable Document Format) to various processes such as RIP (Raster Image Processor) processing or color conversion processing.

[0014] The liquid ejection device 100 has a processing device 120 and a head unit 110. The processing device 120 includes, for example, one or more processing circuits such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array), and one or more storage circuits such as semiconductor memories. The processing device 120 generates print data DP and outputs it to the head unit 110. The processing device 120 also has a function of controlling printing by the head unit 110.

[0015] The head unit 110 has a plurality of nozzles that eject liquid. The head unit 110 ejects ink from each of the plurality of nozzles onto a medium under the control of a drive control unit 20 based on print data DP.

[0016] The processing device 120 may be provided separately from the liquid ejection device 100. In this case, the processing device 120 is, for example, a desktop or notebook computer.

[0017] The server 300 is a computer that functions as a cloud server. The server 300 predicts the lifespan of the liquid ejection head 110a (described below) of the head unit 110 of each liquid ejection device 100. The server 300 generates various types of output information, including information related to deterioration, based on various types of input information from the processing device 120 of each liquid ejection device 100, and outputs the various types of output information to the processing device 120 of each liquid ejection device 100.

[0018] 1-2.Liquid discharge device 100 Fig. 2 is a schematic diagram showing an example of the configuration of the liquid ejection system 1 shown in Fig. 1. As shown in Fig. 2, the liquid ejection device 100 includes a head unit 110, a processing device 120, a communication circuit 120c, a display device 120d, and an input device 120e.

[0019] The head unit 110 has a liquid ejection head 110a and a control module 110b. The liquid ejection head 110a has a head chip 111 and a drive circuit 112. The number of head chips 111 included in the liquid ejection head 110a is not limited to one, and may be two or more. The control module 110b also has a power supply circuit 113 and a drive signal generation circuit 114.

[0020] The head chip 111 ejects ink toward a printing medium. The head chip 111 has a plurality of piezoelectric elements 34. Under the control of the processing device 120, the drive circuit 112 switches whether or not to supply the drive signal Com output from the drive signal generation circuit 114 as a drive pulse PD to each of the plurality of piezoelectric elements 34. The drive circuit 112 includes, for example, a group of switches such as transmission gates for this switching.

[0021] The power supply circuit 113 receives power from a commercial power supply (not shown) and generates various predetermined potentials. The generated potentials are supplied to each section of the liquid ejection head 110a as appropriate. The power supply circuit 113 generates, for example, a power supply potential VHV and a reference voltage VBS. The reference voltage VBS is supplied to the head chip 111. The power supply potential VHV is also supplied to the drive signal generation circuit 114.

[0022] The drive signal generation circuit 114 is a circuit that generates a drive signal Com for driving each piezoelectric element 34. The drive signal generation circuit 114 has, for example, a DA conversion circuit and an amplifier circuit. The DA conversion circuit converts the waveform designation signal dCom output from the processing device 120 from a digital signal to an analog signal. The amplifier circuit generates the drive signal Com by amplifying the analog signal using the power supply potential VHV from the power supply circuit 113. Of the waveforms included in the drive signal Com, the signal with the waveform that is actually supplied to the piezoelectric element 34 is the drive pulse PD.

[0023] The processing device 120 has a processing circuit 120a and a memory circuit 120b. The processing circuit 120a has a function of controlling the operation of each part of the liquid ejection device 100 and a function of processing various data. The processing circuit 120a has, for example, one or more processors such as CPUs.

[0024] The processing circuit 120a controls the operation of each part of the liquid ejection device 100. The processing device 120 generates signals for controlling the operation of each part of the liquid ejection device 100, such as a print data signal SI and a waveform designation signal dCom.

[0025] The print data signal SI is a signal for controlling the driving of the drive circuit 112. The print data signal SI specifies for each predetermined unit period whether the drive circuit 112 supplies the drive signal Com from the drive signal generation circuit 114 as a drive pulse PD to the piezoelectric element 34. This specification specifies the amount of ink to be ejected from the head chip 111, etc. The waveform specification signal dCom is a digital signal for defining the waveform of the drive signal Com generated by the drive signal generation circuit 114.

[0026] The processing circuit 120a has, as functional units, an acquisition unit 121, a notification unit 122, a life extension processing unit 123, and a state confirmation unit 124. The functions of each of these units will be described in detail later. FIG. 2 is a schematic diagram showing the function of the life extension processing unit 123. As will be described later, the life extension processing unit 123 has a setting unit 1231, a waveform correction unit 1232, a potential width change unit 1233, and a drive frequency change unit 1234.

[0027] The storage circuit 120b stores various data such as the recording data DP processed by the processing circuit 120a. The storage circuit 120b includes, for example, one or more volatile memories such as RAM (Random Access Memory) and one or more nonvolatile memories such as ROM (Read Only Memory). The storage circuit 120b may be configured as part of the processing circuit 120a.

[0028] The memory circuit 120b stores information D4 relating to the reference voltage VBS and information D6 relating to the threshold value. The information D4 relating to the reference voltage VBS is information about the reference voltage VBS currently being used by the liquid ejection device 100. The information D6 relating to the threshold value is, for example, information about a threshold value for the lifespan desired by the user. This threshold value indicates the state of the liquid ejection head 110a before the end of its lifespan and when it is nearing the end of its lifespan.

[0029] The communication circuit 120c is an interface for communication connection with the server 300 via the communication network NW. For example, the communication circuit 120c is an interface for wireless communication such as NFC, Wi-Fi, Bluetooth, or a wired LAN. NFC, Wi-Fi, and Bluetooth are registered trademarks. The communication circuit 120b functions as an "output unit." The processing circuit 120a may also be considered to have the function of an "output unit."

[0030] The display device 120d displays various images and outputs sounds under the control of the processing circuit 120a. The display device 120d has, for example, various display panels such as a liquid crystal display panel or an organic EL (electro-luminescence) display panel, and an audio output device such as a speaker. The display device 120d does not necessarily have to include an audio output device. Alternatively, only an audio output device may be provided instead of the display device 120d.

[0031] The input device 120e is a device that accepts operations from a user. For example, the input device 120e has a pointing device such as a touchpad, a touch panel, or a mouse. If the input device 120e has a touch panel, it may also function as the display device 120d. The display device 120d and the input device 120e may be provided outside the liquid ejection device 100. The input device 120e may also include an imaging device having a CCD (Charge Coupled Device) image sensor or the like.

[0032] 1-3.Server 300 The server 300 includes a processing circuit 300a, a memory circuit 300b, a communication circuit 300c, a display device 300d, and an input device 300e. The memory circuit 300b corresponds to a "memory unit."

[0033] The processing circuit 300a has a function of controlling the operation of each unit of the server 300 and a function of processing various data. The processing circuit 300a has, for example, one or more processors such as CPUs. The processing circuit 300a predicts the lifespan of the liquid ejection head 100a of each liquid ejection device 100 by executing various programs including a lifespan prediction program P1 stored in the storage circuit 300b.

[0034] The processing circuit 300a has, as functional units, an acquisition unit 303, a life prediction unit 301, and an update unit 302. The functions of each of these units will be described in detail later.

[0035] The storage circuit 300b stores various programs executed by the processing circuit 300a and various data such as recording data DP processed by the processing circuit 300a. The storage circuit 300b includes, for example, one or more semiconductor memories, such as one or more volatile memories such as RAM (Random Access Memory) and one or more non-volatile memories such as ROM (Read Only Memory). The storage circuit 300b may be configured as part of the processing circuit 300a.

[0036] The memory circuit 300b stores a lifespan prediction program P1, history information D1, correspondence information D5, information D4 related to the reference voltage VBS, lifespan information D3, and deterioration information D2. The lifespan prediction program P1 is a program that causes a computer to implement various functions required to generate lifespan information D3 based on the history information D1 and the correspondence information D5. The history information D1 is information related to the history of the reference voltage VBS. The correspondence information D5 is information related to the correspondence between the reference voltage VBS and the failure rate of the piezoelectric element 34. The lifespan information D3 is information related to the lifespan of the liquid ejection head 110a generated based on the correspondence information D5 and the information D4 related to the reference voltage VBS. The deterioration information D3 is information related to deterioration indicating that the liquid ejection head 110a is in a state before the end of its lifespan and is nearing the end of its lifespan. The deterioration information D3 is generated, for example, based on information D4 related to a threshold output from the liquid ejection device 100.

[0037] The communication circuit 300c is an interface for communicating with each liquid ejection device 100 via the communication network NW. For example, the communication circuit 300c is an interface for wireless communication such as NFC, Wi-Fi, Bluetooth, or a wired LAN. Note that NFC, Wi-Fi, and Bluetooth are all registered trademarks.

[0038] The display device 300d displays various images under the control of the processing circuit 300a. The display device 300d includes various display panels such as a liquid crystal display panel or an organic EL (electro-luminescence) display panel, and an audio output device such as a speaker.

[0039] The input device 300e has a pointing device such as a touch pad, a touch panel, or a mouse. If the input device 300e has a touch panel, it may also serve as the display device 300d.

[0040] The display device 300d and the input device 300e may be provided outside the server 300. The input device 300e may include an imaging device having a CCD (Charge Coupled Device) image sensor or the like.

[0041] 1-4.Head chip The following explanation will use the mutually intersecting X-axis, Y-axis, and Z-axis as appropriate. One direction along the X-axis is called the X1 direction, and the direction opposite to the X1 direction is called the X2 direction. Opposite directions along the Y-axis are called the Y1 direction and the Y2 direction. Opposite directions along the Z-axis are called the Z1 direction and the Z2 direction. Viewing in a direction along the Z-axis is called a "planar view." The Z-axis is typically a vertical axis. The Z1 direction is the upward direction, and the Z2 direction is the downward direction. However, the Z-axis does not have to be a vertical axis. Furthermore, the X-axis, Y-axis, and Z-axis are typically perpendicular to each other.

[0042] FIG. 4 is a cross-sectional view of a portion of the head chip 111 shown in FIG. 2. As shown in FIG. 4, the head chip 111 has a plurality of nozzles N arranged along the Y axis. The plurality of nozzles N are divided into a first row La and a second row Lb that are arranged side by side at intervals along the X axis. Each of the first row La and the second row Lb is a collection of a plurality of nozzles N linearly arranged along the Y axis. The liquid ejection head 110a has a structure in which elements associated with each nozzle N in the first row La and elements associated with each nozzle N in the second row Lb are arranged in approximately plane symmetry. The following description will focus on the elements corresponding to the first row La, and will omit descriptions of the elements corresponding to the second row Lb as appropriate.

[0043] 4, the liquid ejection head 110a includes a communication plate 31, a pressure chamber substrate 32, a vibration plate 33, a plurality of piezoelectric elements 34, a sealing substrate 35, a housing 36, a nozzle substrate 37, a vibration absorber 38, and a wiring substrate 40. The communication plate 31, the pressure chamber substrate 32, the vibration plate 33, the sealing substrate 35, the housing 36, the nozzle substrate 37, and the vibration absorber 38 are each elongated along the Y axis. Contacting members are fixed to each other by, for example, an adhesive or the like.

[0044] The nozzle substrate 37 is a plate-like member on which a plurality of nozzles N are formed. Each of the plurality of nozzles N is a circular through-hole that ejects ink. The nozzle substrate 37 is manufactured by processing a silicon (Si) single crystal substrate using semiconductor manufacturing techniques such as photolithography and etching.

[0045] The communicating plate 31 is formed with a plurality of throttle portions 312, a plurality of communicating channels 314, a communicating space Ra, and a common channel Rb. Each of the throttle portions 312 and the communicating channels 314 extends in the Z1 direction and is a through-hole formed for each nozzle N. The communicating channels 314 overlap the nozzles N in plan view. The communicating spaces Ra are elongated openings formed along the Y axis. The communicating spaces Ra extend along the Y axis. The common channels Rb communicate with the communicating spaces Ra and overlap with the communicating spaces Ra in plan view. The common channels Rb extend along the Y axis. The common channels Rb communicate with the plurality of throttle portions 312. Furthermore, the communicating space Ra communicates the common channels Rb with external channels of the liquid ejection head 110a via a space Rc, which will be described later.

[0046] A plurality of pressure chambers C1 are formed in the pressure chamber substrate 32. The pressure chambers C1 are located between the communication plate 31 and the vibration plate 33, and are spaces formed by the wall surface 320 of the pressure chamber substrate 32. A pressure chamber C1 is formed for each nozzle N. The pressure chamber C1 is an elongated space extending in the X1 direction. The plurality of pressure chambers C1 are arranged along the Y axis. One end of each pressure chamber C1 in the X1 direction is connected to the nozzle N via a communication flow path 314. The other end of each pressure chamber C1 in the X1 direction is connected to a throttle portion 312. The throttle portion 312 has a smaller cross-sectional area than the pressure chamber C1. An individual flow path for each nozzle N is formed by the pressure chamber C1, the nozzle N, the communication flow path 314, and the throttle portion 312. The communication plate 31 and the pressure chamber substrate 32 are manufactured by processing a semiconductor substrate, such as a silicon single crystal substrate.

[0047] An elastically deformable vibration plate 33 is disposed above the pressure chamber C1. The vibration plate 33 is laminated on the pressure chamber substrate 32 and contacts the surface of the pressure chamber substrate 32 opposite the surface from the communication plate 31. The vibration plate 33 is a plate-like member formed in an elongated rectangular shape along the Y axis in a plan view. The thickness direction of the vibration plate 33 is parallel to the Z1 direction. The pressure chamber C1 communicates with the communication flow path 314 and the throttle portion 312. Therefore, the pressure chamber C1 communicates with the nozzle N via the communication flow path 314, and with the communication space Ra via the throttle portion 312. Note that although the pressure chamber substrate 32 and the vibration plate 33 are illustrated in FIG. 4 as separate substrates, they are actually laminated on a single silicon substrate.

[0048] A piezoelectric element 34 is formed for each pressure chamber C1 on the surface of the vibration plate 33 opposite to the pressure chamber C1. The piezoelectric element 34 is also a driving element that is driven when a driving signal is applied thereto.

[0049] The housing 36 is a case for storing ink to be supplied to the multiple pressure chambers C1, and is formed, for example, by injection molding of a resin material. A space Rc and a supply port 361 are formed in the housing 36. The supply port 361 is a conduit through which ink is supplied, and is connected to the space Rc. The space Rc in the housing 36 and the communication space Ra in the communication plate 31 are connected to each other. The communication space Ra, the common flow path Rb, and the space Rc form a common space R that is shared by the multiple nozzles N. The common space R functions as a liquid storage chamber that stores ink to be supplied to the multiple pressure chambers C1. The ink stored in the common space R branches off to each of the throttle sections 312 and is supplied to and filled in parallel into the multiple pressure chambers C1.

[0050] The vibration absorber 38 is a flexible film that forms the wall surface of the communication space Ra, and absorbs pressure fluctuations of the ink in the common space R. The vibration absorber 38 is, for example, a laminate of an ink-resistant resin film, a SUS (stainless steel) member that holds the resin film and has spring properties, and a fixing plate that protects the resin film and the SUS member.

[0051] The sealing substrate 35 is a structure that protects the plurality of piezoelectric elements 34 and reinforces the mechanical strength of the pressure chamber substrate 32 and the vibration plate 33. The plurality of piezoelectric elements 34 are housed inside a recess formed on the surface of the sealing substrate 35 facing the vibration plate 33. A wiring board 40 is inserted into a through hole 362 of the housing part 36 and a through hole 353 of the sealing substrate 35. The wiring board 40 is bonded to the surface of the vibration plate 33. For example, a TCP (Tape Carrier Package) or an FPC (Flexible Printed Circuit) is used as the wiring board 40. A part of the drive circuit 112 is mounted on the wiring board 40. A drive signal and a reference voltage for driving the piezoelectric elements 34 are supplied to each piezoelectric element 34 from the wiring board 40.

[0052] In the liquid ejection head 110a, when the piezoelectric element 34 contracts due to energization, the vibration plate 33 is bent and deflected in a direction that reduces the volume of the pressure chamber C1, and the pressure inside the pressure chamber C1 increases, causing an ink droplet to be ejected from the nozzle N. At this time, pressure also propagates from the pressure chamber C1 toward the throttle portion 312, causing ink to flow into the common flow path Rb through the throttle portion 312. After the ink is ejected, the piezoelectric element 34 returns to its original position. At this time, the ink in the common flow path Rb from the nozzle N also vibrates. Then, at the same time as the meniscus of the nozzle N restores its original shape, ink is supplied from the throttle portion 312. Through the above series of operations, ink is ejected from the nozzle N.

[0053] 1-5.Piezoelectric element Fig. 5 is an enlarged view of the piezoelectric element 34 shown in Fig. 4. As shown in Fig. 5, the piezoelectric element 34 has an individual electrode 341, a piezoelectric layer 342, and a common electrode 343. Note that other members may be interposed between the respective components. For example, an orientation control layer that controls the orientation of the piezoelectric layer 342 may be provided between the individual electrode 341 and the piezoelectric layer 342.

[0054] The individual electrodes 341 are provided individually for each piezoelectric element 34. The individual electrodes 341 extend along the X-axis and overlap with the pressure chambers C1 in a plan view. The common electrode 343 is provided in common to a plurality of piezoelectric elements 34. The common electrode 343 extends along the Y-axis. Examples of materials for each electrode include metal materials or alloys such as platinum (Pt), iridium (Ir), aluminum (Al), nickel (Ni), gold (Au), and copper (Cu). Each electrode may be a single layer or multiple layers.

[0055] A piezoelectric layer 342 is provided for each piezoelectric element 34. For example, the piezoelectric layers 342 may be connected to each other to the extent that they do not overlap with the pressure chamber C1, forming a continuous member. The piezoelectric layers 342 are formed of a piezoelectric material having a perovskite crystal structure, such as lead zirconate titanate (PZT: Pb(Zr,Ti)O3).

[0056] The piezoelectric element 34 is also provided with first wiring 391 and second wiring 392. The first wiring 391 is provided for each individual electrode 341 and is wiring that applies a voltage to the individual electrode 341. The first wiring 391 has a longitudinal shape extending along the X-axis in a plan view. The first wiring 391 has a portion that contacts the upper surface of the individual electrode 341 and a portion that contacts the upper surface of the piezoelectric layer 342. There are two second wirings 392. The two second wirings 392 extend along the Y-axis and are spaced apart from each other. The second wirings 392 also function as weights to suppress vibration of the diaphragm 33.

[0057] 1-6. Drive voltage and reference voltage Fig. 6 is a diagram showing the drive voltage and reference voltage applied to Fig. 5. The horizontal axis in Fig. 6 represents time, and the vertical axis represents voltage [V].

[0058] A voltage is applied to the piezoelectric element 34 by the aforementioned control module 110b. Specifically, the control module 110b applies a voltage to the piezoelectric layer 342 via the common electrode 343 and the individual electrode 341. The piezoelectric layer 342 deforms in response to the voltage applied between the common electrode 343 and the individual electrode 341.

[0059] A driving voltage Com1, which is the voltage of the driving signal Com corresponding to the amount of ink ejection, is applied to the individual electrode 341. The driving voltage Com1 changes over time. The driving voltage Com1 includes a driving waveform WCom. The driving waveform WCom is repeated in a unit period Tu. The driving waveform WCom includes an intermediate voltage Ek, a maximum voltage En, and a minimum voltage Em. The maximum voltage En is the maximum value of the driving voltage Com1. The minimum voltage Em is the minimum value of the driving voltage Com1. The driving waveform WCom drops from the intermediate voltage Ek to the minimum voltage Em, maintains the minimum voltage Em, then rises from the minimum voltage Em to the maximum voltage En, maintains the maximum voltage En, and then drops to the intermediate voltage Ek. The driving voltage Com1 has a predetermined potential width Vh corresponding to the amount of ink ejection. Note that the driving waveform WCom shown in FIG. 6 is an example, and the driving voltage Com1 may have other waveforms.

[0060] A constant reference voltage VBS is applied to the common electrode 343 regardless of the amount of ink ejected. The reference voltage VBS does not change over time and is constant. In the illustrated example, the reference voltage VBS is a voltage value higher than the minimum voltage Em of the drive voltage Com1, but is not limited to this. The reference voltage VBS may also be the GND potential, i.e., 0V.

[0061] 1-7. Server 300 Functions As shown in FIG. 2, the processing circuit 300 a of the server 300 functions as an acquisition unit 303 , a life prediction unit 301 , and an update unit 302 .

[0062] 1-7a. Acquisition section 303 The acquisition unit 303 acquires various information output from each liquid ejection device 100 via a communication device, and stores the information in the storage circuit 300b.

[0063] 1-7b. Life expectancy prediction unit 301 The life prediction unit 301 predicts the life of the liquid ejection head 110a. By having this life prediction unit 301, it is possible to know how long the life of the liquid ejection head 110a will be before it reaches the end of its life. This makes it possible to avoid having to take measures such as replacing the liquid ejection head 110a after the life of the liquid ejection head 110a has reached the end of its life. This makes it possible to avoid downtime.

[0064] The life of the liquid ejection head 110a predicted by the life prediction unit 301 is calculated statistically and refers to a state in which it becomes difficult to use the liquid ejection head 110a. For example, the liquid ejection head 110a may become difficult to use due to a failure of the piezoelectric element 34 or deterioration of the piezoelectric element 34. The time when it becomes difficult to use the liquid ejection head 110a is predicted by the life prediction unit 301 as the end of its life. Therefore, the predicted life is merely a predicted value and may differ from the actual life.

[0065] As described above, the lifespan of the liquid ejection head 110a depends on the failure of the piezoelectric element 34. Failure of the piezoelectric element 34 causes defective liquid ejection, resulting in missing nozzles in the liquid ejection head 110a. Failure of the piezoelectric element 34 is often caused by burnout at the electrode end of the common electrode 343. This failure is a dielectric breakdown that causes cracks 90 to form in the portion of the piezoelectric layer 342 that abuts against the electrode end of the common electrode 343.

[0066] FIG. 7 is a diagram illustrating the dielectric breakdown of the piezoelectric layer 342 shown in FIG. 5. As shown in FIG. 7, as the number of times the piezoelectric element 34 is driven increases, a crack 90 may occur in the portion of the piezoelectric layer 342 that abuts against the electrode end of the common electrode 343. It is difficult to detect dielectric breakdown of the piezoelectric layer 342 before it occurs. This is because there is no precursor to dielectric breakdown, or even if there is a precursor, the time from the occurrence of the precursor to breakdown is very short. In addition, because the voltage pulses that drive the piezoelectric layer 342 are high-frequency, the current value detected in the event of a breakdown is very small compared to the large current value of AC drive, making it difficult to detect the current value detected in the event of a breakdown.

[0067] Therefore, by predicting the end of the life of the liquid ejection head 110a in advance, taking into consideration the failure of the piezoelectric element due to dielectric breakdown of the piezoelectric layer 342, it is possible to prepare for the sudden end of the life of the liquid ejection head 110a, thereby avoiding the occurrence of the downtime mentioned above.

[0068] Furthermore, as mentioned above, failure of the piezoelectric element 34 is often caused by burnout defects occurring at the electrode ends of the common electrode 343. A reference voltage VBS is applied to the common electrode 343. For this reason, predicting the lifespan of the liquid ejection head 110a based on the reference voltage VBS is particularly effective from the perspective of avoiding downtime.

[0069] The life prediction unit 301 predicts information relating to the deterioration of the piezoelectric element 34 based on the correspondence relationship information D5 stored in the memory circuit 300b and the information D4 relating to the reference voltage VBS. By predicting the life based on the correspondence relationship information D5 stored in the memory circuit 300b, it is possible to simplify the prediction of the life.

[0070] FIG. 8 is a diagram showing the correspondence relationship between the reference voltage VBS and the failure rate of the liquid ejection head 110a. The correspondence relationship shown in FIG. 8 is determined by cumulative hazard analysis. The horizontal axis represents the relative lifespan when a predetermined failure rate is set to "1" when the reference voltage VBS is 6V, for example. The horizontal axis may also represent the number of ink ejection shots or the driving time. The vertical axis represents the failure rate of the liquid ejection head 110a.

[0071] FIG. 8 shows the failure rates of the liquid ejection head 110a when the reference voltage VBS is 5V, 6V, and 7V. Consider a case where the liquid ejection head 110a has three head chips 111. First, data on the number of shots or drive time required for a predetermined number of piezoelectric elements 34 to fail is prepared for each of the three head chips 111. Next, a reliability function is generated using the prepared data using the cumulative hazard method to obtain a regression line. The line is drawn when the reference voltage VBS is 5V and 7V, based on the slope of the line when the reference voltage VBS is 6V. Therefore, the slope of the line is the same for the multiple reference voltages VBS of 5V, 6V, and 7V.

[0072] Furthermore, for example, if the failure rate is set to a predetermined value as lifespan Z, the state in which lifespan Z is approaching, i.e., the deterioration of the liquid ejection head 100a, is set to "Y." Deterioration Y is a state in which the failure rate of the liquid ejection head 110a is lower than lifespan Z. This lifespan Z and deterioration Y can be set appropriately for each liquid ejection device 100 by the user and manufacturer. For example, lifespan Z and deterioration Y are set based on the number of liquid ejection heads 110a included in the liquid ejection device 100 or the allowable number of failures of the piezoelectric elements 4.

[0073] The correspondence between the reference voltage VBS and the failure rate of the liquid ejection head 110a is not limited to the graph shown in FIG. 7, but may be, for example, a table or a calculation formula.

[0074] Further, when the reference voltage VBS is the "first potential", the life prediction unit 301 predicts a higher failure rate of the liquid ejection head 110a, that is, a shorter life of the liquid ejection head 110a, than when the reference voltage VBS is the "second potential" smaller than the "first potential". For example, the "first potential" is 6V and the "second potential" is 5V. In this case, when the reference voltage VBS is 6V, the life is predicted to be shorter than when the reference voltage VBS is 5V. That is, the higher the reference voltage VBS, the higher the failure rate of the liquid ejection head 110a, that is, the shorter the life of the liquid ejection head 100a tends to be.

[0075] Further, the life prediction unit 301 predicts the life of the liquid ejection head 110a based on the number of piezoelectric elements 34 provided in the liquid ejection head 110a. When the number of piezoelectric elements 34 provided in the liquid ejection head 110a is N, the life of the liquid ejection head 110a is predicted to be shorter than when the number of piezoelectric elements 34 is M which is less than N. That is, the more the number of piezoelectric elements 34 provided in the liquid ejection head 110a, the shorter the life of the liquid ejection head 110a is predicted. Note that the failure rate corresponding to the deterioration Y of the liquid ejection head 100a is appropriately changed according to the predicted life Z. Note that N is a natural number. M is a natural number. N and M satisfy the relationship N<M.

[0076] Further, as described above, in FIG. 8, the life Z and the deterioration Y are shown. As an example, the method for calculating the life Z in FIG. 8 will be described below. For example, when one liquid ejection device 100 is equipped with one liquid ejection head 110a having 200 piezoelectric elements 34 and the reference voltage VBS is 6V, a reference life is set as a reference. The reference life is set from known data and is set as a constant value. As an example, the reference life is set to a value corresponding to the number of shots until the liquid ejection head 110a fails. The life Z is calculated by multiplying the reference life by a coefficient corresponding to the value of the reference voltage VBS. For example, if one liquid ejection device 100 is equipped with one liquid ejection head 110a having 200 piezoelectric elements 34 and the reference voltage VBS is 7V, the reference life span multiplied by 0.7 will be the life span Z. Also, if one liquid ejection device 100 is equipped with one liquid ejection head 110a having 200 piezoelectric elements 34 and the reference voltage VBS is 5V, the life span Z will be the reference life span multiplied by 1.1. In this way, the life Z is calculated by multiplying the reference life by the coefficient corresponding to the reference voltage VBS.

[0077] Furthermore, the lifespan Z may be calculated by multiplying the lifespan Z by a coefficient corresponding to the parameters of the number of liquid ejection heads 110a and the number of piezoelectric elements 34 in addition to the coefficient corresponding to the reference voltage VBS. For example, if one liquid ejection device 100 is equipped with two liquid ejection heads 110a, each with 200 piezoelectric elements 34, and the reference voltage VBS is 6V, the reference lifespan is multiplied by a coefficient corresponding to the increased number of liquid ejection heads 110a, to obtain lifespan Z. Also, if one liquid ejection device 100 is equipped with one liquid ejection head 110a, each with 400 piezoelectric elements 34, and the reference voltage VBS is 6V, the reference lifespan is multiplied by a coefficient corresponding to the increased number of piezoelectric elements, to obtain lifespan Z. The reference life value and the coefficient to be multiplied may be updated as appropriate based on statistical data.

[0078] Furthermore, the deterioration Y is set, for example, according to the user's request. For example, as will be described later, in the liquid ejection device 100, the user sets the device to notify the user that the end of life is approaching, i.e., that the device is deteriorating, when the device reaches 90% of its lifespan, assuming that the lifespan is 100%. This deteriorating state is set as a first threshold value for the failure rate of the piezoelectric element 34. The first threshold value can be set arbitrarily by the user, for example. The first threshold value may also be set arbitrarily by the manufacturer of the server, etc. The deterioration Y shown in FIG. 8 described above is set based on the first threshold value.

[0079] Then, when the predicted lifespan rate exceeds a first threshold value set by the user, that is, when it exceeds the deterioration Y, the lifespan prediction unit 301 outputs information D3 relating to deterioration to the liquid ejection device 100. Based on this information, the user can know that the lifespan is approaching the end.

[0080] For example, consider a case where the reference voltage VBS is 6V, the number of shots over the lifespan set by the manufacturer is X, and the actual count number of shots is A. In this case, the deterioration Y is determined by the ratio of A / X. If notification is to be given at 90%, when the number of shots reaches A, at which A / X=0.9, the user is notified of deterioration via the liquid ejection device 100.

[0081] The threshold value is not limited to one. For example, there may be two threshold values. Specifically, for example, a state in which the lifespan is likely to be within a few weeks may be set as the first threshold value A1, and a state in which the lifespan is likely to be within a few days may be set as the second threshold value A2. In other words, A / X=0.90 may be set as the first threshold value, and A / X=0.95 may be set as the second threshold value. By setting multiple threshold values ​​in this way, the user can take action to extend the lifespan of the liquid ejection head 110a or replace it each time a threshold value is exceeded.

[0082] As will be described later, the reference voltage VBS can be changed by the user. When the life prediction unit 301 receives information from the liquid ejection device 100 indicating that the user has changed the reference voltage VBS, i.e., when the reference voltage VBS is changed, it predicts the life of the liquid ejection head 110a based on the history of the reference voltage VBS contained in the history information D1. Some users may change the reference voltage VBS between the time the liquid ejection head 110a is installed and the time it fails. Even in this case, the failure rate can be predicted by referring to the history of the reference voltage VBS contained in the history information D1.

[0083] For example, when the reference voltage VBS is set to 6 V, the life prediction unit 301 predicts the life of the liquid ejection head 110a using the regression line of the reference voltage 6 V. If the reference voltage VBS is subsequently changed from 6 V to 5 V, the life prediction unit 301 predicts the life of the liquid ejection head 110a using the regression line of the reference voltage 5 V from the time of the change. More specifically, when the reference voltage VBS is changed from 6V to 5V, the number of shots counted up until the reference voltage VBS was changed from 6V to 5V is subtracted from the number of shots corresponding to the life Z at the reference voltage of 6V. The difference is calculated as the number of remaining shots until the life Z at the reference voltage of 6V is reached. This remaining number of shots is multiplied by the coefficient for when the reference voltage VBS is 5V to update the number of remaining shots after the change, and the life Z is predicted.

[0084] The life prediction unit 301 may also predict the life of the liquid ejection head 110a based on at least one of the temperature and humidity of the liquid ejection head 110a and the reference voltage VBS. The life prediction unit 301 also generates a correspondence relationship between the temperature or humidity and the failure rate of the liquid ejection head 110a using the aforementioned cumulative hazard analysis for the temperature or humidity. The life prediction unit 301 then predicts the life of the liquid ejection head 110a using this correspondence relationship and a correspondence relationship based on the aforementioned reference voltage. Using information about the temperature or humidity in addition to the reference voltage VBS can improve the accuracy of the life prediction.

[0085] 1-7c.Update section 302 The update unit 302 updates the correspondence information D5 including the correspondence stored in the storage circuit 300b of the server 300. For example, the update unit 302 updates the correspondence information D5 periodically or irregularly. The lifespan prediction unit 301 predicts the lifespan based on the updated correspondence, thereby making it possible to predict the lifespan based on a more accurate correspondence.

[0086] 1-8. Functions of the processing device 120 of the liquid ejection device 100 As shown in FIG. 2, the processing device 120 has an acquisition unit 121, a notification unit 122, a life extension processing unit 123, and a state confirmation unit 124 as functional units.

[0087] 1-8a. Acquisition part 121 The acquisition unit 121 acquires various information output from the server 300 via a communication device and stores the information in the memory circuit 120b.

[0088] 1-8b.Notification section 122 The notification unit 122 notifies the liquid ejection head 100a of deterioration based on the deterioration-related information D3 output from the server 300. Specifically, the notification unit 122 outputs a command to notify the display device 120d of the deterioration. The display device 120d notifies the user that the lifespan is approaching by, for example, displaying an image including text or by sound.

[0089] The provision of the notification unit 122 allows the user to know that the liquid ejection head 110a is deteriorating, i.e., that its lifespan is approaching its end, and therefore the user can take various measures, such as replacing the liquid ejection head 110a, before the end of its lifespan is reached.

[0090] Furthermore, the notification unit 122 notifies the user of a message urging the user to replace the liquid ejection head 110a based on the deterioration information D3. By receiving this message, the user can replace the liquid ejection head 110a before the end of its life.

[0091] 1-8c. Life Support Processing Department 123 The life extension processing unit 123 performs a life extension process to extend the life of the liquid ejection head 110a based on the deterioration information D3. As shown in FIG. 3, the life extension processing unit 123 includes a setting unit 1231, a waveform correction unit 1232, a potential width change unit 1233, and a drive frequency change unit 1234.

[0092] The setting unit 1231 changes the reference voltage VBS based on input from the user. The setting unit 1231 allows the user to change the reference voltage VBS, for example, when the user receives a notification from the notification unit 122 that the liquid ejection head 100a has deteriorated. Changing the reference voltage VBS allows the user to extend the life of the liquid ejection head 100a, which is nearing the end of its life. This delays the timing at which the liquid ejection head 110a reaches the end of its life. If preparations are made to replace the liquid ejection head 110a during this time, downtime can be avoided. The setting unit 1231 may also change the reference voltage VBS without receiving a user instruction, for example, when information D3 regarding deterioration is acquired.

[0093] The waveform correction unit 1232 corrects the drive waveform WCom, which is a waveform that drives the liquid ejection head 110a, based on the deterioration information D3. For example, when the user receives a notification from the notification unit 122 that the liquid ejection head 100a has deteriorated, the user may change the drive waveform WCom instead of or in addition to the reference voltage VBS. By changing the drive waveform WCom, it is possible to extend the life of the liquid ejection head 100a that is approaching the end of its life. Note that when the waveform correction unit 1232 detects deterioration of the liquid ejection head 100a based on the deterioration information D3, the drive waveform WCom may be changed without receiving a user instruction.

[0094] The potential width change unit 1233 changes the potential width Vh of the drive waveform WCom based on the deterioration information D3. For example, when the user receives a notification from the notification unit 122 that the liquid ejection head 100a has deteriorated, the user may change the potential width Vh of the drive waveform WCom. By changing the potential width Vh, it is possible to perform a life extension process for the liquid ejection head 100a that is approaching the end of its life. Note that when the potential width change unit 1233 detects deterioration of the liquid ejection head 100a based on the deterioration information, the potential width Vh may be changed without receiving an instruction from the user.

[0095] The drive frequency change unit 1234 changes the drive frequency of the drive waveform WCom based on the deterioration information D3. For example, when the user receives a notification from the notification unit 122 that the liquid ejection head 100a has deteriorated, the user may change the drive frequency of the drive waveform WCom. By changing the drive frequency, it is possible to extend the life of the liquid ejection head 100a that is approaching the end of its life. Note that when the drive frequency change unit 1234 detects deterioration of the liquid ejection head 100a based on the deterioration information, the drive frequency may be changed without receiving an instruction from the user.

[0096] The life extension processing performed by the life extension processing unit 123 can extend the life of the liquid ejection head 110a. This can delay the timing when the life of the liquid ejection head 110a comes to an end. This can reduce the downtime that occurs until the liquid ejection head 110a is replaced.

[0097] 1-8d. Status confirmation section 124 The status checking unit 124 checks the status of the piezoelectric element 23 based on the deterioration information D3. The status checking unit 124 checks whether there is an actual failure by, for example, detecting minute vibrations of the nozzle, measuring voltage and current, printing a test pattern, or video evaluation using a camera. Furthermore, as the failure rate increases, i.e., as the lifespan shortens, the timing of checking the status of the piezoelectric element 34 may be increased.

[0098] Although the lifespan prediction unit 301 of the server 300 described above can predict that the lifespan is approaching, some users may not want to replace the liquid ejection head 110a until it actually breaks. For this reason, the status confirmation unit 124 can prevent replacement of a liquid ejection head 110a that is nearing the end of its lifespan but is still usable and has not yet reached its end of life. This improves usability.

[0099] 1-9. Processing of Liquid Discharge System 1 9 is a flowchart showing the processing of the liquid ejection system 1 according to the first embodiment. As shown in FIG. 9, in the liquid ejection system 1, first, in step S101, the acquisition unit 303 of the server 300 acquires information D4 relating to the reference voltage VBS of the piezoelectric element 34 from the processing device 120. Under the control of the communication circuit 120b, the information D4 relating to the reference voltage VBS is output via the communication circuit 120c, which serves as an "output unit." Furthermore, step S101 is executed each time the reference voltage VBS is changed by the liquid ejection device 100.

[0100] Step S102 is a process in which the life prediction unit 301 of the server 300 predicts the life of the liquid ejection head 110a based on information D4 related to the reference voltage VBS. Specifically, information related to the deterioration of the liquid ejection head 110a is predicted based on correspondence information D5, which has been created in advance and stored in the memory circuit 300b, and information D4 related to the reference voltage VBS.

[0101] Step S103 is a process in which the processing device 120 of the liquid ejection device 100 receives a user's request regarding the first threshold value of the lifespan via the input device 120e. For example, if the lifespan is set to 100%, the user may set the device to notify the user that the lifespan is approaching, i.e., that the device is deteriorating, when the device reaches 90% of the threshold. Note that step S103 may be performed before step S102.

[0102] Step S104 is a process in which the acquisition unit 303 of the server 300 acquires information D6 relating to the threshold value of the life from the processing device 120.

[0103] In step S105, the life prediction unit 301 determines whether the shot count A exceeds the first threshold. The server 300 appropriately acquires information about the shot count A from the liquid ejection device 100. For example, the server 300 acquires information about the shot count A when a user starts or finishes printing, when the liquid ejection device 100 is started up, etc. The shot count A is the number of times that the liquid ejection head 110a ejects ink. The shot count A may be counted by a sensor or the like, or may be calculated from the print data. In addition, when the life prediction unit 301 predicts the life of the liquid ejection head 110a based on at least one of the temperature and humidity of the piezoelectric element 34 and the reference voltage VBS, the server appropriately acquires information regarding at least one of the temperature and humidity. In step S106, when the number of shots A exceeds the first threshold, the life prediction unit 301 outputs deterioration-related information D3 to the liquid ejection device 100. In step S107, the user is notified that the liquid ejection head 110a has deteriorated. That is, in step S107, the notification unit 122 of the liquid ejection device 100 notifies the user via the display device 120d that the life is approaching the end.

[0104] Step S108 is a step in which the processing device 120 of the liquid ejection device 100 receives a request for life extension processing from the user via the input device 120e. Step S109 is a step in which the life extension processing unit 123 of the processing device 120 performs the life extension processing. Specifically, for example, in step S108, the setting unit 1231 changes the reference voltage VBS of the piezoelectric element 34. If the reference voltage VBS has been changed, the process returns to step S101.

[0105] Note that step S108 may be omitted. In other words, the liquid ejection device 100 may perform the life extension process without a request from the user. Furthermore, if no request is received in step S108, step S109 is omitted. Furthermore, steps S108 and S109 may be omitted, that is, the life extension process may not be performed.

[0106] Step S110 is a process in which the liquid ejection apparatus 100 determines whether the liquid ejection head 110a has been replaced. If the liquid ejection head 110a has been replaced, the process returns to step S101.

[0107] According to the processing of the liquid ejection system 1, the user can know that the life of the liquid ejection head 110a is approaching the end of its life before it expires. This makes it possible to avoid having to take measures such as replacing the liquid ejection head 110a after the life of the liquid ejection head 110a has expired. This makes it possible to avoid downtime.

[0108] 2. Second embodiment In the second embodiment below, the elements having the same functions as those in the first embodiment will be designated by the same reference numerals used in the description of the first embodiment, and detailed description of each element will be omitted as appropriate.

[0109] Fig. 10 is a schematic diagram illustrating the configuration of a liquid ejection system 1A according to the first embodiment. In the example shown in Fig. 10, the server 300 is omitted, and the liquid ejection system 1A is configured with a liquid ejection device 100A. In this case, the liquid ejection device 100A has the functions of the server 300 in the first embodiment.

[0110] Specifically, a life prediction unit 125 and an update unit 126 are provided, which have the same functions as the life prediction unit 301 and the update unit 302. The acquisition unit 121 of the first embodiment is omitted. The memory circuit 120b of this embodiment corresponds to the "memory unit." The memory circuit 120b stores history information D1, correspondence information D5, information D4 about the reference voltage VBS, information D2 about deterioration, information D3 about the life, and information D6 about the threshold value.

[0111] In this embodiment, as in the first embodiment, by having the life prediction unit 125, it is possible to know how long the life of the liquid ejection head 110a will be before it reaches its end of life. This makes it possible to avoid having to take measures such as replacing the liquid ejection head 110a after the life of the liquid ejection head 110a has reached its end. This makes it possible to avoid downtime.

[0112] Furthermore, the life prediction unit 301 predicts information relating to deterioration of the liquid ejection head 100a based on the currently used reference voltage VBS and correspondence relationship information D5, which includes the correspondence relationship stored in the memory circuit 120b. By predicting the lifespan based on the correspondence relationship information D5 stored in the memory circuit 120b, it is possible to simplify the lifespan prediction.

[0113] 3. Variations The above-described exemplary embodiment may be modified in various ways. Specific modifications that may be applied to the above-described exemplary embodiment are exemplified below.

[0114] The server 300 may include either or both of the life extension processing unit 123 and the state confirmation unit 124 in the first embodiment.

[0115] In the first embodiment, the reference voltage VBS is 5V, 6V, and 7V, but the reference voltage VBS is not limited to these. Furthermore, the reference voltage VBS used is not limited to 1V intervals, and the intervals are arbitrary. For example, the lifetime may be predicted at 0.1V intervals.

[0116] The "liquid ejection head" may be a circulation type head having a so-called circulation flow path.

[0117] A "liquid ejection device" can be employed in various devices such as facsimile machines and copiers, as well as devices dedicated to printing. The uses of a liquid ejection device are not limited to printing. For example, a liquid ejection device that ejects a solution of a color material is used as a manufacturing device for forming color filters for display devices such as liquid crystal display panels. A liquid ejection device that ejects a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes on a wiring board. A liquid ejection device that ejects a solution of an organic substance related to a living organism is used as a manufacturing device for manufacturing biochips, for example.

[0118] Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the above-described embodiments. Furthermore, the configuration of each part of the present invention can be replaced with any configuration that exhibits the same function as the above-described embodiments, and any configuration can be added. [Explanation of symbols]

[0119] 1...liquid ejection system, 4...piezoelectric element, 20...drive control unit, 23...piezoelectric element, 31...communicating plate, 32...pressure chamber substrate, 33...vibration plate, 34...piezoelectric element, 35...sealing substrate, 36...casing unit, 37...nozzle substrate, 38...vibration absorber, 40...wiring substrate, 90...crack, 100...liquid ejection device, 110...head unit, 110a...liquid ejection head, 110b...control module, 111...head chip, 112...drive circuit, 113...power supply circuit, 114...drive signal generation circuit, 120...processing device, 120a...processing circuit, 120b...storage circuit, 120c...communication circuit, 120d...display device, 120e...input device, 121...acquisition unit, 122...notification unit, 123...life extension processing unit, 124...status confirmation unit, 125...life prediction unit, 126...change New unit, 300...server, 300a...processing circuit, 300b...storage circuit, 300c...communication circuit, 300d...display device, 300e...input device, 301...life expectancy prediction unit, 302...updating unit, 303...acquisition unit, 312...throttling unit, 314...communicating flow path, 320...wall surface, 341...individual electrode, 342...piezoelectric layer, 343...common electrode, 353...through hole, 361...supply port, 36 2...through hole, 391...first wiring, 392...second wiring, 1231...setting section, 1232...waveform correction section, 1233...potential width changing section, 1234...driving frequency changing section, C1...pressure chamber, D1...history information, D3...information, D4...information, D5...correspondence information, D6...information, DP...recorded data, N...nozzle, NW...communication network, P1...life prediction program, PD...driving pulse.

Claims

1. a liquid ejection head having a piezoelectric element and configured to eject liquid; a life prediction unit that predicts a life of the liquid ejection head based on a reference voltage of the piezoelectric element; having A liquid ejection system comprising:

2. The liquid ejection system according to claim 1 , a setting unit that changes the reference voltage based on an input from a user; A liquid ejection system comprising:

3. The liquid ejection system according to claim 2 , a storage unit that stores a history of the reference voltage; The life prediction unit When the reference voltage is changed, the life of the liquid ejection head is predicted based on the history. A liquid ejection system comprising:

4. The liquid ejection system according to claim 2 , a storage unit that stores a correspondence relationship between the reference voltage and the failure rate of the piezoelectric element; the life prediction unit predicts information regarding deterioration of the piezoelectric element based on the correspondence relationship stored in the storage unit and the reference voltage. A liquid ejection system comprising:

5. The liquid ejection system according to any one of claims 1 to 4, the life prediction unit predicts a shorter life of the liquid ejection head when the reference voltage is a first potential than when the reference voltage is a second potential lower than the first potential; A liquid ejection system comprising:

6. The liquid ejection system according to any one of claims 1 to 4, The life prediction unit predicting a lifespan of the liquid ejection head based on the number of the piezoelectric elements provided in the liquid ejection head; When the number of the piezoelectric elements provided in the liquid ejection head is N (N is a natural number), the lifespan is predicted to be shorter than when the number of the piezoelectric elements is M (M is a natural number, N>M). A liquid ejection system comprising:

7. The liquid ejection system according to any one of claims 1 to 4, an output unit that outputs information related to the reference voltage; a server that stores information about the reference voltage output from the output unit, the server storing a correspondence relationship between the reference voltage and a failure rate of the piezoelectric element; The life prediction unit predicting the life of the liquid ejection head based on the information relating to the reference voltage and the correspondence relationship; A liquid ejection system comprising:

8. The liquid ejection system according to claim 7, an update unit that updates the correspondence relationship stored in the server; A liquid ejection system comprising:

9. The liquid ejection system according to any one of claims 1 to 4, the life prediction unit predicts the life of the liquid ejection head based on at least one of the temperature and humidity of the piezoelectric element and the reference voltage; A liquid ejection system comprising:

10. The liquid ejection system according to any one of claims 1 to 4, the life prediction unit outputs information regarding deterioration of the liquid ejection head. A liquid ejection system comprising:

11. The liquid ejection system according to any one of claims 1 to 4, a notification unit that notifies the liquid ejection head of deterioration based on information regarding deterioration of the piezoelectric element; A liquid ejection system comprising:

12. The liquid ejection system according to claim 11, the notification unit notifies a message urging replacement of the liquid ejection head based on the information regarding the deterioration. A liquid ejection system comprising:

13. The liquid ejection system according to any one of claims 1 to 4, a waveform correction unit that corrects a waveform for driving the liquid ejection head based on the information relating to the deterioration; A liquid ejection system comprising:

14. The liquid ejection system according to any one of claims 1 to 4, a life extension processing unit that performs a life extension process for extending the life of the liquid ejection head based on the information about the deterioration; A liquid ejection system comprising:

15. The liquid ejection system according to any one of claims 1 to 4, a state confirmation unit that confirms the state of the piezoelectric element based on the information about the deterioration; A liquid ejection system comprising:

16. The liquid ejection system according to any one of claims 1 to 3, The life prediction unit outputting information about the degradation when the predicted failure rate exceeds a first threshold selected by a user; A liquid ejection system comprising:

17. A control method for controlling a liquid ejection system including a liquid ejection head having a piezoelectric element and ejecting liquid, comprising: obtaining a reference voltage of the piezoelectric element; and predicting a lifespan of the liquid ejection head based on the reference voltage. A control method comprising:

18. A control method for controlling a liquid ejection system including a liquid ejection head having a piezoelectric element and ejecting liquid, comprising: changing a reference voltage of the piezoelectric element; obtaining the reference voltage; notifying the liquid ejection head of deterioration based on the reference voltage. A control method comprising:

Images