JP4894898B2 - Fluid ejection device - Google Patents

Description

The present invention relates to a fluid ejection device.

  As a fluid ejecting apparatus, an ink jet recording apparatus that ejects ink onto a recording medium from an ejection port of a recording head is known. If the ink is not ejected from the ejection port for a long time, the viscosity of the ink in the recording head increases, and there is a possibility that the ink cannot be ejected satisfactorily. Therefore, for example, as disclosed in Patent Document 1 below, operations such as flushing operation and suction operation are periodically performed to discharge ink from the ejection ports.

JP 2006-123499 A

  If the operation of discharging the ink is executed even though the viscosity of the ink has not increased, the ink is wasted. Although it is conceivable to predict the change in the viscosity of the ink and perform the operation of discharging the ink according to the predicted result, the environment (temperature, humidity, etc.) in which the ink jet recording apparatus is used is not constant. It is difficult to predict changes in ink viscosity.

  The present invention has been made in view of the above circumstances, and provides a fluid ejection device capable of suppressing wasteful consumption of fluid such as ink and maintaining a good ejection state, and a control method for the fluid ejection device. Objective.

In order to solve the above problems, the present invention adopts the following configuration.
According to the first aspect of the present invention, the ejection head having an ejection surface on which an ejection port for ejecting fluid is formed is disposed so as to face the ejection surface through a predetermined gap, and ejected from the ejection port. A detection unit that outputs a detection signal corresponding to the fluid ejected from the ejection port, and obtains information on the viscosity of the fluid based on the detection signal A processing device that measures the elapsed time from a reference time, outputs the measurement value, a maintenance device that can maintain the ejection head, and a measurement value output from the measurement device, And a control device that controls the maintenance device, wherein the measurement device is provided with a fluid ejection device that changes the output measurement value according to information acquired by the processing device.

  According to the first aspect of the present invention, since the detection device outputs a detection signal corresponding to the fluid ejected from the ejection port, the viscosity of the fluid actually ejected from the ejection port is based on the detection signal. Information can be acquired. When maintenance processing by the maintenance device is executed according to the measurement value of the measurement device that measures the elapsed time from the reference time, the measurement value can be changed based on the information about the viscosity of the fluid acquired by the processing device. Therefore, appropriate maintenance processing can be performed by the maintenance device. Thereby, wasteful consumption of fluid can be suppressed and a good injection state can be maintained.

  In the above configuration, the reference time may include a configuration including the end of the maintenance process executed earlier. Thereby, a favorable injection state can be maintained.

  The said structure WHEREIN: The said control apparatus can employ | adopt the structure which controls the said maintenance apparatus according to the measured value after a change. Thereby, an appropriate maintenance process can be performed.

  In the above configuration, the content of maintenance processing by the maintenance device is set corresponding to the elapsed time from the reference time, and the control device sets the content of the maintenance processing based on the measured value. A configuration for controlling the maintenance device based on the set contents can be employed. Thereby, an appropriate maintenance process can be performed.

  In the above configuration, the maintenance device can perform a maintenance process including an operation of discharging the fluid from the ejection port in cooperation with the ejection head in order to maintain the ejection characteristics of the ejection head. The maintenance process can be executed in a plurality of modes in which the discharge amount of the fluid discharged from the ejection port is different from each other, and the control device selects a specific mode from the plurality of modes based on the measurement value. Further, it is possible to adopt a configuration in which the maintenance device is controlled to perform the maintenance process in the selected mode. Thereby, it is possible to execute an appropriate maintenance process while suppressing wasteful consumption of fluid, and to maintain a good injection state.

  In the above-described configuration, the maintenance process may include a process of executing a flushing operation for injecting the fluid in advance from the injection port before supplying the fluid from the injection port to a predetermined object. Thereby, a favorable discharge state can be maintained.

  The said structure can employ | adopt the structure containing the capping apparatus which has the cap member which can form a space between the said injection surfaces, and the suction device which can attract | suck the fluid of the said space. According to this, the ejection head can be satisfactorily maintained using the capping device.

  In the above configuration, the maintenance device may include a configuration including the detection unit. According to this, since the members are shared by the maintenance device and the detection device, it is possible to improve the processing efficiency of each of the maintenance processing and the detection processing, and to realize space saving of the device.

  In the above-described configuration, the detection device applies an electric field between the ejection surface and the detection unit, and temporally calculates a voltage value based on electrostatic induction when the fluid moves from the ejection port to the detection unit. A configuration that outputs changes can be employed. Thereby, the information regarding the viscosity of the fluid can be acquired favorably.

  In the above configuration, the detection signal includes the voltage value for each of the first timing, the second timing after the first time has elapsed from the first timing, and the third timing after the second time has elapsed from the second timing. The voltage value is a reference value from the first timing to the second timing, the voltage value starts changing at the second timing, and the voltage value becomes an extreme value at the third timing, The processing device obtains at least one of the first time, the second time, and a difference between the reference value and the extreme value, and obtains information on the viscosity of the fluid based on the obtained result. Can be adopted. According to this, since at least one of the first time, the second time, and the difference between the reference value and the extreme value changes according to the viscosity of the fluid, the information on the viscosity of the fluid is good based on the change. Can be obtained.

  In the above configuration, in order to eject the fluid from the ejection port, a drive element that varies the pressure of the space connected to the ejection port based on an input drive signal is provided, and the first timing is the drive A configuration including a time when a drive signal is input to the element can be employed. In the above configuration, the second timing includes a time when the ejection of the fluid is started from the ejection port, and the third timing includes a time when the fluid from the ejection port reaches the detection unit. Configuration can be adopted. Thereby, the information regarding the viscosity of the fluid can be acquired favorably.

  In the above configuration, a storage device that stores a reference signal output from the detection device based on a fluid in an initial state, and the processing device from the initial state based on the detection signal and the reference signal is provided. A configuration for acquiring information related to the amount of change in the viscosity of the fluid can be employed. According to this, the amount of change in the viscosity of the fluid from the initial state can be favorably obtained.

  In the above configuration, the detection signal includes the voltage value for each of the first timing, the second timing after the first time has elapsed from the first timing, and the third timing after the second time has elapsed from the second timing. The voltage value is a reference value from the first timing to the second timing, the voltage value starts changing at the second timing, and the voltage value becomes an extreme value at the third timing, The reference signal includes the voltage value for each of the first timing, the fourth timing after the third time has elapsed from the first timing, and the fifth timing after the fourth time has elapsed from the fourth timing, From the timing to the fourth timing, the voltage value is a reference value, and at the fourth timing, the voltage value is The voltage value becomes an extreme value at the fifth timing, and the processing device provides information on the difference between the first time and the third time, and the difference between the second time and the fourth time. And at least one of information on the difference between the extreme value of the detection signal and the extreme value of the reference signal, and the information on the viscosity of the fluid is obtained based on the obtained result. . According to this, according to the viscosity of the fluid with respect to the initial state, the difference between the first time and the third time, the difference between the second time and the fourth time, and the extreme value of the detection signal and the extreme value of the reference signal Since at least one of the differences changes, information on the viscosity of the fluid can be favorably acquired based on the change.

  In the above configuration, in order to eject the fluid from the ejection port, a drive element that varies the pressure of the space connected to the ejection port based on an input drive signal is provided, and the first timing is the drive A configuration including a time when a drive signal is input to the element can be employed. In the above configuration, the second timing and the fourth timing include a time when the fluid starts to be ejected from the ejection port, and the third timing and the fifth timing are fluids from the ejection port. It is possible to adopt a configuration including the time when the sensor reaches the detection unit. Thereby, the information regarding the viscosity of the fluid can be acquired favorably.

  In the above configuration, the fluid may be a liquid. Thereby, the detection apparatus can output the detection signal according to the liquid ejected from the ejection port satisfactorily.

  According to a second aspect of the present invention, there is provided a control method for a fluid ejecting apparatus including an ejecting head having an ejecting surface on which an ejection port for ejecting fluid is formed, and is opposed to the ejecting surface through a predetermined gap. The process which arrange | positions a detection part to supply the said fluid injected from the said ejection outlet to the said detection part, and acquires the detection signal according to the said fluid ejected from the said ejection opening using the said detection part And based on the detection signal, processing for obtaining information on the viscosity of the fluid, measuring elapsed time from a reference time, outputting the measurement value, and according to the output measurement value, A control method in which the output measurement value is changed according to the information on the viscosity.

  According to the second aspect of the present invention, since the detection signal corresponding to the fluid ejected from the ejection port is acquired, information on the viscosity of the fluid actually ejected from the ejection port is acquired based on the detection signal. can do. In the case where the maintenance process is executed according to the measurement value obtained by measuring the elapsed time from the reference time, the appropriate maintenance process can be executed by changing the measurement value based on the acquired information on the viscosity of the fluid. Thereby, wasteful consumption of fluid can be suppressed and a good injection state can be maintained.

1 is a perspective view showing an ink jet printer according to a first embodiment. 1 is a plan view showing an ink jet printer according to a first embodiment. FIG. 3 is a cross-sectional view illustrating the recording head according to the first embodiment. It is a perspective view which shows the maintenance apparatus which concerns on 1st Embodiment. It is the perspective view which looked at a part of maintenance device concerning a 1st embodiment from the lower part. It is a figure which shows an example of the suction device which concerns on 1st Embodiment. It is a figure for demonstrating the detection system which concerns on 1st Embodiment. It is a schematic diagram for demonstrating the principle of the detection operation of a detection apparatus. It is a figure which shows an example of the detection signal output from the detection apparatus which concerns on 1st Embodiment. It is a block diagram which shows the electrical structure of an inkjet printer. It is a figure which shows an example of the maintenance content matched with the elapsed time from the reference time. It is a figure which shows an example of the drive signal input into a piezoelectric element. It is a flowchart for demonstrating an example of operation | movement of the inkjet printer which concerns on 1st Embodiment. It is a figure which shows the relationship between the detection signal which concerns on 1st Embodiment, and a reference signal. It is a figure which shows an example of the change conditions of the measured value set corresponding to the information regarding the viscosity of an ink. It is a flowchart for demonstrating an example of operation | movement of the inkjet printer which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
A first embodiment will be described. FIG. 1 is a perspective view illustrating an example of a fluid ejection device according to the first embodiment, and FIG. 2 is a plan view. In the present embodiment, a case where the fluid ejecting apparatus is a liquid ejecting apparatus (liquid ejecting apparatus) that ejects a liquid (liquid material) such as ink will be described as an example. In the present embodiment, an example will be described in which the fluid ejecting apparatus is an ink jet recording apparatus that ejects ink onto a recording medium from an ejection port of a recording head and executes recording on the recording medium. In the present embodiment, as an example of an ink jet recording apparatus, an ink jet printer that performs recording on a recording paper by ejecting (jetting) ink droplets onto the recording paper as a recording medium will be described.

  1 and 2, the ink jet printer 1 includes a recording unit 2 that performs recording on a recording sheet with ink, and a recording sheet conveyance mechanism 3 that conveys the recording sheet.

  The recording unit 2 includes a recording head 4 that ejects ink, a carriage 5 that can move while supporting the recording head 4, and a recording sheet on which ink is ejected. And a supporting platen 6.

  The ink jet printer 1 also includes a carriage driving device 7 including a motor that moves the carriage 5 and a carriage guide member that guides the movement of the carriage 5. The carriage 5 is moved in the main scanning direction by the carriage driving device 7 while being guided by the carriage guide member. The recording paper is moved in the sub-scanning direction intersecting the main scanning direction with respect to the recording unit 2 by the recording paper transport mechanism 3.

  The inkjet printer 1 also includes a detection system 8 that can detect the ejection state of the recording head 4 and the ink ejected from the recording head 4. The detection system 8 of this embodiment can detect information related to the viscosity of the ink ejected from the recording head 4.

  The ink jet printer 1 includes a paper feed cassette 9 that stores recording paper. The paper feed cassette 9 is detachably provided on the back side of the main body of the inkjet printer 1. The paper feed cassette 9 can store a plurality of stacked recording papers.

  The recording paper transport mechanism 3 includes a paper feeding roller for carrying out the recording paper in the paper feeding cassette 9, a paper feeding roller driving device 10 including a motor for driving the paper feeding roller, and recording for guiding the movement of the recording paper. A paper guide member 11, a transport roller disposed downstream in the transport direction with respect to the paper feed roller, a transport roller driving device that drives the transport roller, and a downstream of the recording unit 2 in the transport direction And a discharge roller.

  The paper feed roller can pick up the recording paper arranged on the uppermost side among the plurality of recording papers stacked in the paper feed cassette 9 and can carry it out of the paper feed cassette 9. The recording paper in the paper feeding cassette 9 is fed to the conveying roller by the paper feeding roller driven by the paper feeding roller driving device 10 while being guided by the recording paper guide member 11. The recording paper sent to the transport roller is transported to the recording unit 2 arranged on the downstream side in the transport direction by the transport roller driven by the transport roller driving device.

  The platen 6 of the recording unit 2 is disposed at a position facing the recording head 4 and the carriage 5 and supports the lower surface of the recording paper. The recording head 4 and the carriage 5 are disposed above the platen 6. The recording paper transport mechanism 3 transports the recording paper in the sub-scanning direction in conjunction with the recording operation by the recording unit 2. The recording paper recorded by the recording unit 2 is discharged from the front side of the inkjet printer 1 by a recording transport mechanism 3 including a discharge roller.

  The ink jet printer 1 also includes an ink supply tube 12 that supplies ink from the ink cartridge to the recording head 4 of the carriage 5. The ink in the ink cartridge is supplied to the ink supply path via the ink supply needle, and is supplied from the ink supply path to the recording head 4 of the carriage 5 via the ink supply tube 12.

  The ink jet printer 1 also includes a maintenance device 13 that can maintain the recording head 4. The maintenance device 13 includes a capping device 14 and a wiping device 15. The maintenance device 13 is disposed at the home position of the carriage 5 and the recording head 4. The home position is set in an end area outside the recording area in which the recording operation by the recording unit 2 is executed, within the movement area of the carriage 5. When the power is turned off or when the recording operation is not performed for a long time, the carriage 5 and the recording head 4 are arranged at the home position.

  In the present embodiment, at least part of the detection system 8 capable of detecting the ejection state of the recording head 4 and the ink ejected from the recording head 4 is disposed in the maintenance device 13 (capping device 14).

  FIG. 3 is a cross-sectional view showing a part of the recording head 4. The recording head 4 includes an ejection surface 17 on which an ejection port 16 that ejects ink is formed. In the present embodiment, the ejection port 16 can eject ink droplets. A plurality of injection ports 16 are formed at predetermined intervals in a predetermined direction on the injection surface 17.

  The recording head 4 includes a head main body 18 and a flow path forming unit 22 including a vibration plate 19, a flow path substrate 20, and a nozzle substrate 21. The ejection surface 17 is formed by the lower surface of the nozzle substrate 21. The injection port 16 is formed in the nozzle substrate 21. The flow path forming unit 22 is a unit in which the diaphragm 19, the flow path substrate 20, and the nozzle substrate 21 are laminated and joined together with an adhesive or the like.

  The recording head 4 includes an accommodation space 23 formed in the head body 18 and a drive unit 24 disposed in the accommodation space 23. The drive unit 24 includes a plurality of piezoelectric elements 25, a fixing member 26 that supports the upper end of the piezoelectric elements 25, and a flexible cable 27 that supplies a drive signal to the piezoelectric elements 25. The piezoelectric element 25 is provided so as to correspond to each of the plurality of ejection ports 16.

  In addition, the recording head 4 is formed inside the head main body 18, and an internal flow path 28 through which ink supplied from the ink cartridge via the ink supply tube 12 flows, a vibration plate 19, a flow path substrate 20, and a nozzle substrate. 21, a common ink chamber 29 formed by a flow path forming unit 22 including the flow path 21 and connected to the internal flow path 28, an ink supply port 30 formed by the flow path forming unit 22 and connected to the common ink chamber 29, A pressure chamber 31 formed by the path forming unit 22 and connected to the ink supply port 30 is provided. A plurality of pressure chambers 31 are provided so as to correspond to the plurality of injection ports 16. Each of the plurality of injection ports 16 is connected to each of the plurality of pressure chambers 31.

  The head body 18 is made of synthetic resin. The diaphragm 19 is obtained by laminating an elastic film on a metal support plate such as stainless steel. An island portion 32 joined to the lower end of the piezoelectric element 25 is formed at a portion corresponding to the pressure chamber 31 of the vibration plate 19. At least a part of the diaphragm 19 is elastically deformed according to the driving of the piezoelectric element 25. A compliance portion 33 is formed between the diaphragm 19 and the vicinity of the lower end of the internal flow path 28.

  The flow path substrate 20 has a recess for forming spaces for the common ink chamber 29, the ink supply port 30, and the pressure chamber 31 that connect the lower end of the internal flow path 28 and the ejection port 16. In the present embodiment, the flow path substrate 20 is formed by anisotropic etching of silicon.

  The nozzle substrate 21 has a plurality of injection ports 16 formed at a predetermined interval (pitch) in a predetermined direction. The nozzle substrate 21 of the present embodiment is a plate-like member formed of a metal such as stainless steel.

  The ink supplied from the ink cartridge via the ink supply tube 12 flows into the upper end of the internal flow path 28. The lower end of the internal flow path 28 is connected to the common ink chamber 29, and the ink that has flowed into the upper end of the internal flow path 28 from the ink cartridge via the ink supply tube 12 flows through the internal flow path 28 and is then shared. The ink is supplied to the ink chamber 29. The ink supplied to the common ink chamber 29 is supplied through the ink supply port 30 so as to be distributed to each of the plurality of pressure chambers 31.

  When a drive signal is input to the piezoelectric element 25 via the cable 27, the piezoelectric element 25 expands and contracts. As a result, the diaphragm 19 is deformed (moved) in a direction toward and away from the pressure chamber 31. As a result, the volume of the pressure chamber 31 changes, and the pressure of the pressure chamber 31 containing ink fluctuates. The ink is ejected (discharged) from the ejection port 16 due to the fluctuation of the pressure.

  As described above, the piezoelectric element (drive element) 25 of the present embodiment ejects ink from the ejection port 16, so that the pressure chamber (space) 31 connected to the ejection port 16 is based on the input drive signal. Vary the pressure.

  4 is a perspective view showing the maintenance device 13, and FIG. 5 is a perspective view of a part of the maintenance device 13 as viewed from below. The maintenance device 13 includes a capping device 14 and a wiping device 15.

  4 and 5, the capping device 14 includes a cap member 34 that can face the ejection surface 17 of the recording head 4. The cap member 34 can cover the ejection surface 17. The cap member 34 can form a space between the ejection surface 17 and the cap member 34.

  The capping device 14 also includes a base member 36 and a drive mechanism 37 that moves the cap member 34 toward and away from the ejection surface 17 of the recording head 4 disposed at the home position. . The drive mechanism 37 is mounted on a base member 36 as disclosed in, for example, Japanese Patent Laid-Open No. 2006-272779, and moves while guiding the cap member 34 toward and away from the ejection surface 17. And a spring member disposed between the base member 36 and the slider member 38.

  The capping device 14 includes a suction device 35 that can suck a fluid in a space formed between the cap member 34 and the ejection surface 17. As shown in FIG. 5, the capping device 14 includes a suction tube 39 connected to the bottom of the cap member 34, and the suction device 35 is connected to the suction tube 39. The suction device 35 of this embodiment includes a tube pump as disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-314622.

  FIG. 6 is a diagram illustrating an example of the suction device 35. In FIG. 6, the suction device 35 includes a roller member 40 and a tube member 41. The tube member 41 has flexibility and is curved in an annular shape. Both ends of the tube member 41 are arranged so as to be drawn out in the same direction. One end of the tube member 41 is connected to the cap member 34 via the suction tube 39, and the other end of the tube member 41 is connected to a waste ink tank (not shown). The roller member 40 is movable so as to roll on the inner periphery of the annular portion 41 </ b> A of the tube member 41.

  The suction device 35 includes a rotating plate 40T that rotatably supports the roller member 40 and that can rotate about the rotation shaft 40X, and a driving device that rotates the rotating plate 40T. In the present embodiment, the drive device that rotates the rotating plate 40T includes, for example, the paper feed roller drive device 10 of the recording paper transport mechanism 3, and the power of the paper feed roller drive device 10 is provided in the suction device 35. Is transmitted to the rotating plate 40T via the gear unit 10G. As the rotating plate 40T rotates, the roller member 40 revolves and rolls along the inner periphery of the annular portion 40A of the tube member 41.

  While the roller member 40 crushes the tube member 41, the fluid (air, ink, etc.) in the tube member 41 is moved (rotated) in the direction of the arrow Y 1 in FIG. Squeezed out (to the waste ink tank side). That is, as the roller member 40 rotates, the fluid on one end side (cap member side) in the tube member 41 moves to the other end side. Thereby, the suction device 35 can make a negative pressure in the space formed between the ejection surface 17 and the cap member 34 via the suction tube 39.

  By creating a negative pressure in the space formed between the ejection surface 17 and the cap member 34, ink is sucked from the ejection ports 16 of the ejection surface 17, or ink in the space is sucked into the suction tube 39 and the suction device 39. It can be discharged outside the space (waste ink tank) via the tube member 41.

  Further, the roller member 40 can be moved away from the tube member 41 so that the tube member 41 is not crushed by the roller member 40.

  In addition, as a structure of the tube pump, instead of a form in which both ends of the annularly curved tube member are drawn in the same direction and bundled in the same plane as shown in FIG. It is also possible to adopt a configuration in which both ends of the member are drawn out in opposite directions to intersect each other. Further, as the suction device 35, for example, a tube pump as disclosed in Japanese Patent Application Laid-Open No. 2006-257828 can be used.

  As shown in FIG. 5, the capping device 14 includes an atmosphere release tube 42 connected to the bottom of the cap member 34 and an atmosphere release valve 43 provided on the atmosphere release tube 42. By opening the atmosphere release valve 43, air can be introduced into the space formed between the ejection surface 17 and the cap member 34 via the atmosphere release tube 42. Therefore, when the space formed between the ejection surface 17 and the cap member 34 is in a negative pressure state by the suction device 35, the space is opened to the atmosphere by opening the atmosphere release valve 43, and the space is negatively charged. The pressure state is released.

  In FIG. 4, the wiping device 15 includes a wiping member 44 that can face the ejection surface 17 of the recording head 4. In the present embodiment, the wiping member 44 is disposed on a part of the base member 36. The wiping member 44 is disposed on the recording unit 2 side (recording area side) with respect to the cap member 34. The wiping device 15 can wipe or remove foreign matter adhering to the ejection surface 17 such as remaining ink by using the wiping member 44.

  The inkjet printer 1 can perform maintenance processing on the recording head 4 using the maintenance device 13. In order to maintain the ejection characteristics of the recording head 4, the maintenance device 13 cooperates with the recording head 4 to perform a maintenance process including an operation of discharging ink from the ejection ports 16.

  The maintenance process includes at least one of a flushing operation for ejecting ink from the ejection port 16 to the cap member 34 and a suction operation using the cap member 34 and the suction device 35 of the capping device 14. The maintenance process includes a wiping process using the wiping device 15.

  The flushing operation includes an operation of ejecting (discharging) ink from the ejection port 16 in advance to the cap member 34 at the home position before supplying ink from the ejection port 16 to the recording paper in the recording region. As a result, the ink with increased viscosity in the vicinity of the ejection port 16 is discharged, and the ejection characteristics of the ejection port 16 are maintained or recovered.

  In the home position, the injection surface 17 and the cap member 34 are opposed to each other at the home position, and the space formed between the injection surface 17 and the cap member 34 is made negative by using the suction device 35. The operation includes sucking ink from the ejection port 16 of the surface 17. As a result, ink with increased viscosity that could not be discharged by the flushing operation, dust that has entered the ejection port 16, bubbles in the recording head 4, and the like are ejected from the ejection port 16 together with the ink. Is maintained or recovered.

  The wiping operation includes an operation in which the ejection surface 17 and the wiping member 44 are opposed to each other and the ejection surface 17 is wiped by the wiping member 44 at the home position. Thereby, foreign matters (including residual ink) adhering to the ejection surface 17 including the ejection port 16 are removed, and the ejection characteristics of the ejection port 16 are maintained or recovered.

  FIG. 7 is a schematic diagram for explaining the detection system 8. The detection system 8 can detect the ink ejection state of the ejection ports 16 of the recording head 4 and the ink ejected from the ejection ports 16 of the recording head 4. Further, the detection system 8 can detect information related to the viscosity of the ink ejected from the ejection ports 16 of the recording head 4.

  In FIG. 7, the ink supply tube 12 connects the ink cartridge 48 and the sub tank 51 connected to the recording head 4, and the ink supplied from the ink cartridge 48 to the ink supply tube 12 is supplied to the sub tank 51. The In the present embodiment, the ink cartridge 48 includes a case member 49 and an ink pack 50 housed in the case member 49 and formed of a plastic material. The sub tank 51 has an ink chamber 52, and the ink supplied to the ink chamber 52 is supplied to the recording head 4.

  In FIG. 7, the detection system 8 includes a detection unit 45 that is disposed so as to face the ejection surface 17 of the recording head 4 with a predetermined gap, and that is supplied with ink ejected from the ejection port 16. A detection device 46 that outputs a detection signal corresponding to the ink ejected from the mouth 16 and a processing device 47 that acquires information related to the viscosity of the ink based on the detection signal output from the detection device 46 are provided.

  The detection device 46 includes a voltage applicator 53 that applies a voltage between the detection unit 45 and the ejection surface 17 of the recording head 4, and a voltage detector 54 that detects the voltage of the detection unit 45.

  In this embodiment, the detection part 45 of the detection apparatus 46 is provided inside the cap member 34 of the maintenance apparatus 13 (capping apparatus 14) arrange | positioned at a home position. That is, in the present embodiment, the maintenance device 13 (capping device 14) includes the detection unit 45 of the detection device 46.

  The cap member 34 is a tray-like member having an opening at the top, and is formed of an elastic member such as an elastomer. An ink absorber 55 and an electrode member 56 are disposed inside the cap member 34. The electrode member 56 is formed of a metal mesh member (lattice-like member) such as stainless steel. The detection unit 45 is formed by the upper surface of the electrode member 56. The detection unit 45 is disposed at a position lower than the upper end surface 57 of the cap member 34. The upper end surface 57 is the surface of the cap member 34 that is closest to the ejection surface 17, and the detection unit 45 is disposed at a position slightly away from the upper end surface 57 with respect to the ejection surface 17.

  The ink absorber 55 is formed of a sponge-like member capable of holding (absorbing) ink or a porous member. In the present embodiment, the ink absorber 55 is formed of a nonwoven fabric such as felt. During non-recording, the ink absorbed by the ink absorber 55 moisturizes the space formed by the ejection surface 17 and the cap member 34 coming into contact with each other, and suppresses drying of the ink in the ejection port 16. . Depending on the ink, the ink may absorb moisture, and in that case, the ink absorber may not be provided. That is, the ink absorber is disposed as necessary.

  The ink supplied to the detection unit 45 passes through the gap between the electrode members 56 and is held (absorbed) by the ink absorber 55. The electrode member 56 may not be a mesh member as long as ink can pass through. When there is no ink absorber 55, the electrode member 56 is held by a rib provided so as to extend from the bottom surface of the cap member 34. As described above, the suction tube 39 is connected to the bottom of the cap member 34, and the ink of the ink absorber 55 is sucked into the suction device 35 through the suction tube 39.

  The voltage applicator 53 includes an electronic circuit that can apply a voltage between the ejection surface (lower surface) 17 of the nozzle substrate 21 of the recording head 4 and the detection unit (upper surface) 45 of the electrode member 56. In the present embodiment, the voltage applicator 53 electrically connects the electrode member 56 and the nozzle substrate 21 via a DC power source and a resistance element so that the electrode member 56 is a positive electrode and the nozzle substrate 21 is a negative electrode. Connecting.

  As described above, the nozzle substrate 21 is formed of a metal such as stainless steel, the electrode member 56 is formed of a metal such as stainless steel, and each of the nozzle substrate 21 and the electrode member 56 has conductivity. The voltage applicator 53 can apply a voltage between the ejection surface 17 and the detection unit 45.

  The voltage detector 54 integrates and outputs the voltage signal of the electrode member 56, an inverting amplifier circuit that inverts and amplifies the signal output from the integration circuit, and a signal output from the inverting amplifier circuit. A / D conversion circuit for A / D converting and outputting.

  In the present embodiment, the detection device 46 applies an electric field between the ejection surface 17 and the detection unit 45, and a voltage value time based on electrostatic induction when ink moves from the ejection port 16 to the detection unit 45. The change is output to the processing device 47 as a detection signal. The processing device 47 can perform arithmetic processing on the output of the detection device 46, and can acquire information relating to the viscosity of the ink based on the detection signal output from the detection device 46.

  FIG. 8 is a schematic diagram for explaining the principle of the detection operation of the detection device 46. By driving the piezoelectric element 25 in a state where a voltage is applied between the ejection surface 17 of the nozzle substrate 21 and the detection unit 45 of the electrode member 56 by the voltage applicator 53, an ink droplet is ejected from the ejection port 16 ( Discharged). In the present embodiment, since the nozzle substrate 21 is a negative electrode, as shown in FIG. 8A, a portion of the negative charge on the nozzle substrate 21 moves to the ink droplets, and the ejected ink droplets. Is negatively charged. As the ink droplet ejected from the ejection port 16 approaches the detection unit 45 of the electrode member 56, the positive charge is increased in the detection unit 45 by electrostatic induction. Thereby, the voltage between the ejection surface 17 of the nozzle substrate 21 and the detection unit 45 of the electrode member 56 is higher than the initial voltage value in a state where ink droplets are not ejected due to the induced voltage generated by electrostatic induction. . Thereafter, as shown in FIG. 8B, when the ink droplet contacts the detection unit 45, the positive charge of the detection unit 45 is neutralized by the negative charge of the ink droplet. As a result, the voltage between the ejection surface 17 of the nozzle substrate 21 and the detection unit 45 of the electrode member 56 is lower than the initial voltage value. Thereafter, the voltage between the ejection surface 17 of the nozzle substrate 21 and the detection unit 45 of the electrode member 56 returns to the initial voltage value.

  Here, in the following description, the ejection surface 17 and the detection unit 45 that are detected when ink is not ejected from the ejection port 16 with an electric field applied between the ejection surface 17 and the detection unit 45. The voltage value between (the initial voltage value) is appropriately referred to as a reference value V0.

  In FIG. 9, ink droplets are ejected (ejected) from the ejection port 16 in a state where a voltage is applied between the ejection surface 17 and the detection unit 45 and an electric field is applied between the ejection surface 17 and the detection unit 45. It is a figure which shows an example of the time change (detection signal) VT of the voltage value output from the voltage detector 54 of the detection apparatus 46 at the time of doing. In FIG. 9, the horizontal axis represents time, and the vertical axis represents voltage value.

  As shown in FIG. 9, the detection signal VT includes the first timing T1, the second timing T2 after the first time D1 has elapsed from the first timing T1, and the second timing T2 after the second time D2 has elapsed. The voltage value for each of the third timings T3 is included.

  The voltage value is the reference value V0 from the first timing T1 to the second timing T2, the voltage value starts changing at the second timing T2, and the voltage value is the extreme value (maximum value) at the third timing T3. ) VP.

  In the detection signal VT shown in FIG. 9, the first timing T <b> 1 is when a drive signal is input to the drive element 25. The second timing T2 is when ink droplet ejection (ejection) is started from the ejection port 16. The third timing T3 is when the ink droplet from the ejection port 16 reaches (contacts) the detection unit 45.

  When a drive signal is input to the piezoelectric element 25 at the first timing T1 in order to eject (discharge) ink droplets from the ejection port 16, a change in pressure in the pressure chamber 31 connected to the ejection port 16 is started. . After the drive signal is input to the piezoelectric element 25 at the first timing T1, the pressure in the pressure chamber 31 reaches a predetermined value, and the ink from the ejection port 16 is discharged at the second timing T2 after the first time D1 has elapsed. Drop ejection (discharge) is started. In other words, when the ink droplet from the ejection port 16 moves from the ejection surface 17 to the detection unit 45, the second timing T2 is the moment when the movement of the ink droplet is started.

  As described with reference to FIG. 8, the ink droplets ejected from the ejection ports 16 are negatively charged, and the ink droplets ejected from the ejection ports 16, that is, the ink from the ejection ports 16. The voltage value begins to change at the moment when a drop of water drops.

  After the ejection of ink droplets from the ejection port 16 is started, as the ink droplets ejected from the ejection port 16 approach the detection unit 45 of the electrode member 56, as described with reference to FIG. Due to the induction, positive charges increase in the detection unit 45. The voltage value gradually increases due to the induced voltage generated by electrostatic induction. Then, at the third timing T3 when the ink droplet from the ejection port 16 reaches (contacts) the detection unit 45, the voltage value becomes the maximum value VP.

  Thereafter, as described with reference to FIG. 8, when the ink droplet contacts the detection unit 45, the positive charge of the detection unit 45 is neutralized by the negative charge of the ink droplet. As a result, after the third timing T3, the voltage value gradually decreases, and after the predetermined time has elapsed from the third timing T3, the voltage value falls below the reference value V0 and becomes the minimum value VU. Return to the reference value V0.

  The detection signal VT of the detection device 46 is output to the processing device 47. The processing device 47 obtains the first time D1, the second time D2, the reference value V0, and the maximum value VP based on the detection signal VT output from the detection device 46. The processing device 47 obtains at least one of the first time D1, the second time D2, and the difference between the reference value V0 and the extreme value VP (maximum value VP with respect to the reference value V0), and based on the obtained result, Obtain information about ink viscosity.

  Each of the first time D1, the second time D2, and the maximum value VP with respect to the reference value V0 varies according to the viscosity of the ink ejected from the ejection port 16.

  For example, when the viscosity of the ink ejected from the ejection port 16 is higher than the viscosity of the ink in the initial state, after the first timing T1 when the drive signal is input to the piezoelectric element 25, the pressure in the pressure chamber 31 is a predetermined value. And the first time D1 until the second timing T2 at which the ink droplets are ejected from the ejection port 16 becomes longer.

  That is, when ink is ejected based on a predetermined driving force by the piezoelectric element 25 (drive unit 24), it is difficult to eject ink if the viscosity of the ink is high, and it is easy to eject ink if the viscosity of the ink is low. Become. When ejecting ink based on a predetermined driving force by the piezoelectric element 25 (drive unit 24), if the viscosity of the ink is increased compared to the initial state, it becomes difficult to eject the ink. The first time D1 from when the drive signal is input to when the ink is ejected from the ejection port 16 becomes longer.

  When the viscosity of the ink ejected from the ejection port 16 is higher than the viscosity of the ink in the initial state, after the second timing T2 when the ejection of the ink droplet from the ejection port 16 is started, the ejection port 16 The second time D2 until the third timing T3 at the moment when the ink reaches the detection unit 45 becomes longer.

  That is, when ink is ejected based on a predetermined driving force by the piezoelectric element 25 (drive unit 24), if the viscosity of the ink is high, the moving speed of the ink between the ejecting surface 17 and the detection unit 45 (ink droplets). The flying speed of the ink drops), and when the viscosity of the ink is low, the moving speed of the ink (the flying speed of the ink droplets) increases. When ink is ejected based on a predetermined driving force by the piezoelectric element 25 (drive unit 24), if the viscosity of the ink is increased compared to the initial state, the moving speed of the ink (the flying speed of the ink droplets). Therefore, the second time D2 from when the ink is ejected from the ejection port 16 to when the ink reaches the detection unit 45 becomes longer.

  Further, when the viscosity of the ink ejected from the ejection port 16 is higher than the viscosity of the ink in the initial state, the maximum value VP with respect to the reference value V0 becomes small.

  In other words, the maximum value VP with respect to the reference value V0 varies according to the amount of ink ejected from the ejection port 16 (size and volume of one ink droplet). When the ink droplet size is large, the maximum value VP increases, and when the ink droplet size is small, the maximum value VP decreases. When ejecting ink based on a constant driving force by the piezoelectric element 25 (drive unit 24), if the viscosity of the ink is increased compared to the initial state, it becomes difficult to eject the ink. The size (volume) of the droplet is reduced, and as a result, the maximum value VP with respect to the reference value V0 is reduced.

  Thus, in this embodiment, ink is applied from the ejection port 16 in a state where a voltage is applied between the ejection surface 17 and the detection unit 45 and an electric field is applied between the ejection surface 17 and the detection unit 45. By ejecting the droplets, the detection device 46 can output a temporal change (detection signal) VT of the voltage value based on electrostatic induction when the ink moves from the ejection port 16 to the detection unit 45.

  Then, the processing device 47, based on the detection signal VT output from the detection device 46, specifically, at least one of the first time D1, the second time D2, and the difference between the reference value V0 and the maximum value VP. Based on the information, information on the viscosity of the ink ejected from the ejection port 16 can be acquired.

  In addition, the ink ejected from the ejection port 16 is based not only on the first time D1, the second time D2, and the difference between the reference value V0 and the maximum value VP but also, for example, the difference between the reference value V0 and the minimum value VU. It is possible to obtain information on the viscosity of As described above, the amount of ink ejected from the ejection port 16 (the size and volume of one ink droplet) changes according to the viscosity of the ink. Since the minimum value VU with respect to the reference value V0 changes according to the amount of ink, information on the viscosity of the ink ejected from the ejection port 16 is acquired based on the difference between the reference value V0 and the minimum value VU. Can do.

  Further, when ink is ejected from the ejection port 16, the detection signal VT output from the detection device 46 changes, and therefore the detection system 8 is based on the detection signal VT output from the detection device 46. It is possible to determine the ink ejection state of the ejection port 16, such as whether ink is ejected from the ejection port 16 of the recording head 4 (whether ejection failure has occurred).

  Further, when the ink ejected from the ejection port 16 contacts (arrives) the detection unit 45, the detection signal VT output from the detection device 46 changes, and thus the detection signal VT output from the detection device 46. The detection system 8 can detect the ink ejected from the ejection ports 16 of the recording head 4. The detection system 8 can detect the amount of ink ejected from the ejection port 16 (size and volume of ink droplets) based on the detection signal VT (extreme value VP).

  Here, the first time D1 and the extreme value VP of the detection signal VT output from the detection device 46 correspond to the drive state (including drive force, drive signal, and drive waveform) of the drive unit 24 including the piezoelectric element 25. Even change. Therefore, the detection system 8 performs an operation of acquiring information related to the viscosity of the ink while the drive state of the drive unit 24 is fixed.

  Further, the second time D2 of the detection signal VT output from the detection device 46 also varies depending on the distance between the ejection surface 17 and the detection unit 45. Therefore, the detection system 8 performs an operation of acquiring information related to the viscosity of the ink in a state where the distance (gap) between the ejection surface 17 and the detection unit 45 is constant.

  That is, the detection system 8 always executes the same ejection condition when ejecting ink from the ejection port 16 when performing the operation of acquiring information related to the viscosity of the ink.

  FIG. 10 is a block diagram showing an electrical configuration of the inkjet printer 1. The ink jet printer 1 in this embodiment includes a control device 58 that controls the operation of the entire ink jet printer 1. The control device 58 includes an input device 59 for inputting various information related to the operation of the ink jet printer 1, a storage device 60 storing various information related to the operation of the ink jet printer 1, and a measuring device 61 capable of measuring time. It is connected. The control device 58 is connected to the recording paper transport mechanism 3, the carriage drive device 7, the maintenance device 13, the detection system 8 (the detection device 46, the processing device 47), and the like.

  The measuring device 61 can measure the elapsed time t from the reference time and output the measured value. The control device 53 controls the maintenance device 13 according to the measurement value output from the measurement device 61. In the present embodiment, the control device 58 uses the maintenance device 13 to perform maintenance processing on the recording head 4 at a predetermined timing. The reference time includes the end of the maintenance process executed first (most recently).

  The storage device 60 stores a timer cleaning table as shown in FIG. The timer cleaning table includes information on the contents (maintenance mode) of a plurality of maintenance processes set in association with the elapsed time t from the most recently performed maintenance process in order to eliminate the ejection failure of the ejection port 16. .

  The timer cleaning table is data acquired in advance by an experiment or simulation of an environmental test at the time of manufacture at the manufacturing factory of the inkjet printer 1, for example, and is stored in advance in the storage device 60 at the time of shipment from the manufacturing factory. The

  The timer cleaning table is executed most recently so that the ejection failure of the ejection port 16 can be eliminated, for example, under the worst conditions of the usage environment assumed for the inkjet printer 1 (for example, high temperature and low humidity conditions such as a temperature of 40 ° C. and a humidity of 10%). Information related to the contents (maintenance mode) of a plurality of maintenance processes set in association with the elapsed time t from the maintenance process performed.

  In the present embodiment, the maintenance process includes a flushing operation and a suction operation, which are operations for discharging ink from the ejection ports 16. In the present embodiment, the maintenance device 13 can perform maintenance processing in a plurality of maintenance modes in which the amount of ink discharged from the ejection port 16 is different from each other. In the timer cleaning table, a plurality of maintenance modes with different amounts of ink discharged from the ejection ports 16 are set in association with the elapsed time t.

  In the timer cleaning table shown in FIG. 11, as an example, flushing that ejects 2000 ink droplets as a maintenance process in association with the case where the elapsed time t from the most recently performed maintenance process is less than 50 hours. The operation is set. If the elapsed time t is less than 50 hours, the flushing operation for ejecting 2000 ink droplets is executed so that the ejection failure of the ejection port 16 can be eliminated even under worst conditions. It has been confirmed by tests. In the present embodiment, when the elapsed time t is 0, a flushing operation for ejecting 1000 ink droplets is executed.

  Similarly, a suction operation for sucking 1.5 g of ink is set in association with the elapsed time t being 50 hours or more and less than 100 hours, and the elapsed time t is 100 hours or more and less than 150 hours. The suction operation for sucking 2.5 g of ink is set in association with, and the suction operation for sucking 3.5 g of ink is associated with the case where the elapsed time t is 150 hours or more and less than 200 hours. Is set.

  Here, in the following description, a maintenance mode including a flushing operation for ejecting 1000 ink droplets is appropriately referred to as a first mode, and a maintenance mode including a flushing operation for ejecting 2000 ink droplets is appropriately used. , Referred to as a second mode. A maintenance mode including a suction operation for sucking 1.5 g of ink is appropriately referred to as a third mode, and a maintenance mode including a suction operation for sucking 2.5 g of ink is appropriately referred to as a fourth mode. A maintenance mode including a suction operation for sucking 3.5 g of ink is appropriately referred to as a fifth mode.

  As shown in FIG. 10, the inkjet printer 1 includes a drive signal generator 62 that generates a drive signal to be input to the drive unit 24 including the piezoelectric element 25. The drive signal generator 62 is connected to the control device 58.

  The drive signal generator 62 receives data indicating the amount of change in the voltage value of the ejection pulse input to the piezoelectric element 25 of the recording head 4 and a timing signal that defines the timing for changing the voltage of the ejection pulse. The drive signal generator 62 generates a drive signal including, for example, the ejection pulse DP shown in FIG. 12 based on the input data and timing signal.

  In FIG. 12, the ejection pulse DP includes a first charging element PE1 that raises the potential with a predetermined gradient from the reference potential VM to the highest potential VH, a first hold element PE2 that maintains the highest potential VH for a certain time, and a highest potential VH. Discharge element PE3 that lowers the potential from the minimum potential VL to the minimum potential VL with a predetermined gradient, a second hold element PE4 that maintains the minimum potential VL for a short time, and a second charging element PE5 that returns the potential from the minimum potential VL to the reference potential VM Including. The drive voltage VD, which is the potential difference between the highest potential VH and the lowest potential VL, of the ejection pulse DP is set so that the amount of ink droplets ejected from the ejection port 16 matches the design value. Note that the ejection pulse DP shown in FIG. 12 is an example, and various waveforms can be used.

  When the ejection pulse DP is input to the piezoelectric element 25 from the drive signal generator 62, an ink droplet is ejected from the ejection port 16. When the first charging element PE1 is supplied, the piezoelectric element 25 contracts and the pressure chamber 31 expands. After the expansion state of the pressure chamber 31 is maintained for a short time, the discharge element PE3 is supplied and the piezoelectric element 25 is rapidly expanded. Along with this, the volume of the pressure chamber 31 contracts to a reference volume (the volume of the pressure chamber 31 when the reference potential VE is applied to the piezoelectric element 25) or less, and the meniscus exposed to the injection port 16 suddenly outwards. Pressure. As a result, a predetermined amount of ink droplets are ejected from the ejection port 16. Thereafter, the second hold element PE4 and the second charging element PE5 are sequentially supplied to the piezoelectric element 25, and the pressure chamber 31 returns to the reference volume so as to converge the meniscus vibration accompanying the ejection of the ink droplets in a short time. To do.

  Next, an example of the operation of the inkjet printer 1 having the above-described configuration will be described with reference to the flowchart of FIG. 13 mainly focusing on the operations of the detection system 8 and the maintenance device 13.

  At a predetermined timing, the control device 58 commands the start of the detection operation using the detection system 8 (step SA1). The operation of supplying ink from the ejection port 16 (recording operation) is sequentially performed on a plurality of recording papers. In this embodiment, the control device 58 supplies the ink from the ejection ports 16 to the recording paper. Before the detection, the detection operation using the detection system 8 is executed.

  As described above, in this embodiment, before the ink from the ejection port 16 is supplied to the recording paper in the recording area, a flushing operation is performed in which ink is ejected in advance from the ejection port 16 to the cap member 34 at the home position. The In the present embodiment, the detection system 8 acquires information related to the viscosity of the ink using the ink ejected by the flushing operation. In other words, in the present embodiment, the detection operation of the detection system 8 is executed for each flushing operation.

  In order to detect information related to the viscosity of the ink, the control device 58 arranges the detection unit 45 so as to face the ejection surface 17 with a predetermined gap at the home position. In the present embodiment, the control device 58 performs the detection operation by the detection system 8 in a state where the ejection surface 17 and the upper end surface 57 of the cap member 34 are slightly separated from each other.

  And the control apparatus 58 performs the operation | movement (viscosity information acquisition operation | movement) which detects the information regarding the viscosity of an ink using the detection system 8 (step SA2).

  In the viscosity information acquisition operation, the control device 58 supplies a drive signal to the drive unit 24 using the drive signal generator 62, and ejects ink droplets from one of the plurality of ejection ports 16. Run the action. The ink droplets ejected from the ejection port 16 are supplied to the detection unit 45. As described with reference to FIG. 9 and the like, the voltage detector 54 outputs a detection signal corresponding to the ink ejected from the ejection port 16 to the processing device 47. The processing device 47 acquires information related to the viscosity of the ink based on the detection signal.

  In the present embodiment, the reference signal VR to be output from the detection device 46 based on the ink in the initial state is stored in the storage device 60 in advance. The ink in the initial state includes the ink before the viscosity increases or the ink in the ideal state. Information regarding the reference signal VR can be acquired in advance by experiments or simulations, for example, at the time of manufacture in a manufacturing factory or the like of the inkjet printer 1. The reference signal VR is stored in advance in the storage device 60 at the time of shipment from the manufacturing factory.

  Based on the detection signal VT output from the detection device 46 and the reference signal VR stored in the storage device 60, the processing device 47 provides information on the amount of change (increase) in the viscosity of the ink from the initial state. get.

  FIG. 14 is a diagram illustrating the relationship between the reference signal VR and the detection signal VT. As described with reference to FIG. 9, the detection signal VT includes the first timing T1, the second timing T2 after the first time D1 has elapsed from the first timing T1, and the second timing T2 to the second timing T2. The voltage value about each of the 3rd timing T3 after time D2 progress is included. The voltage value is the reference value V0 from the first timing T1 to the second timing T2, the voltage value starts to change (increase) at the second timing T2, and the voltage value is the maximum value at the third timing T3. It becomes VP.

  The reference signal VR includes a first timing T1, a fourth timing T4 after the third time D3 has elapsed from the first timing T1, and a fifth timing T5 after the fourth time D4 has elapsed from the fourth timing T4. Including the voltage value for. The voltage value is the reference value V0 from the first timing T1 to the fourth timing T4, the voltage value starts to change (increase) at the fourth timing T4, and the voltage value is the maximum value at the fifth timing T5. VPR.

  In the detection signal VT, the first timing T1 is when a drive signal is input to the piezoelectric element 25. The second timing T2 is when the ejection of ink droplets from the ejection port 16 is started. The third timing T3 is when the ink droplet from the ejection port 16 reaches (contacts) the detection unit 45.

  In the reference signal VR, a first timing T1 is a timing corresponding to when a drive signal is input to the piezoelectric element 25. The fourth timing T4 is a timing corresponding to when the ejection of ink droplets from the ejection port 16 is started. The fifth timing T5 is a timing corresponding to the time when the ink droplet from the ejection port 16 reaches (contacts) the detection unit 45.

  When the viscosity of the ink ejected from the ejection port 16 is higher than the viscosity of the ink in the initial state, the first time D1 of the detection signal VT is longer than the third time D3 of the reference signal VR. Therefore, the processor 47 determines the difference between the first time D1 that can be obtained from the detection signal VT and the third time D3 that can be obtained from the reference signal VR, or the ratio between the first time D1 and the third time D3. Based on this, information on the viscosity of the ink with respect to the initial state can be acquired.

  In addition, when the viscosity of the ink ejected from the ejection port 16 is higher than the viscosity of the ink in the initial state, the second time D2 of the detection signal VT is longer than the fourth time D4 of the reference signal VR. Therefore, the processor 47 determines the difference between the second time D2 that can be obtained from the detection signal VT and the fourth time D4 that can be obtained from the reference signal VR, or the ratio between the second time D2 and the fourth time D4. Based on this, information on the viscosity of the ink with respect to the initial state can be acquired.

  Further, when the viscosity of the ink ejected from the ejection port 16 is higher than the viscosity of the ink in the initial state, the maximum value VP of the detection signal VT is smaller than the maximum value VPR of the reference signal VR. Therefore, the processing device 47 performs initial processing based on the difference between the maximum value VP that can be obtained from the detection signal VT and the maximum value VPR that can be obtained from the reference signal VR, or the ratio between the maximum value VP and the maximum value VPR. Information about the viscosity of the ink for the state can be obtained.

  As described above, the processing device 47 includes information on the difference or ratio between the first time D1 and the third time D3, information on the difference or ratio between the second time D2 and the fourth time D4, and the maximum value of the detection signal VT. It is possible to obtain at least one piece of information relating to the difference or ratio between the VP and the maximum value VPR of the reference signal VR, and obtain information relating to the viscosity of the ink with respect to the initial state based on the obtained result.

  The operation for acquiring information related to the viscosity of the ink ejected from one ejection port 16 among the plurality of ejection ports 16 has been described above. The control device 58 also causes the other ejection ports 16 to perform an operation of ejecting ink one by one from each ejection port 16. The control device 58 uses the detection system 8 to individually perform a detection operation for each of the ejection ports 16 and to perform an operation of acquiring information regarding the viscosity of the ink ejected from each of the ejection ports 16.

  The control device 58 controls the operation of the ink jet printer 1 based on the information regarding the viscosity of the ink ejected from each ejection port 16 obtained using the detection system 8. In the present embodiment, the control device 58 changes the measurement value output from the measurement device 61 according to the information regarding the viscosity of the ink ejected from the ejection port 16 acquired by the detection system 8 including the processing device 47. (Step SA3).

  FIG. 15 is a diagram illustrating an example of a condition for changing the measurement value output from the measurement device 61 that is set in association with the information regarding the viscosity of the ink acquired by the detection system 8. In the present embodiment, the relationship between the information relating to the viscosity of the ink shown in FIG. 15 and the measurement value changing condition is stored in the storage device 60 in advance.

  The viscosity information value R shown in FIG. 15 includes, for example, values relating to the ratio and difference between the third time D3 and the first time D1. Specifically, the viscosity information value R is (D1-D3) / D3. In FIG. 15, the viscosity information value R is shown as a percentage. As the viscosity information value R is smaller, the viscosity of the ink as detected by the detection system 8 is not changed from the initial state (the viscosity is not increased).

  In the present embodiment, the measurement value output from the measurement device 61 is changed according to the viscosity information value R acquired using the detection system 8. When the viscosity information value R is small (when the viscosity of the ink has not increased compared to the initial state), the elapsed time t from the reference time (at the end of the most recently executed maintenance process) becomes a small value. When the viscosity information value R is large (when the ink viscosity is increased with respect to the initial state), the elapsed time t from the reference time is changed to a large value.

  In the example shown in FIG. 15, when the viscosity information value R is less than 5%, the maintenance mode of the maintenance process to be executed is set to the first mode, that is, the elapsed time t after the change is shown in FIG. The measured value output from the measuring device 61 is changed so as to be 0 hours in the timer cleaning table shown. In FIG. 15, t is defined as a numerical value of 0 or more.

  When the viscosity information value R is 5% or more and less than 10%, the maintenance mode of the maintenance process to be executed is set to the second mode, that is, the elapsed time t after the change is the timer cleaning table shown in FIG. The measured value output from the measuring device 61 is changed so that it is less than 50 hours.

  When the viscosity information value R is 10% or more and less than 15%, the maintenance mode of the maintenance process executed thereafter is set to the third mode, that is, the elapsed time t after the change is the timer shown in FIG. The measurement value output from the measurement device 61 is changed so that it is 50 hours or more and less than 100 hours in the cleaning table.

  When the viscosity information value R is 15% or more and less than 20%, the maintenance mode of the maintenance process to be executed is set to the fourth mode, that is, the elapsed time t after the change is the timer cleaning table shown in FIG. The measured value output from the measuring device 61 is changed so that the time becomes 100 hours or more and less than 150 hours.

  When the viscosity information value R is 20% or more, the maintenance mode of the maintenance process to be executed is set to the fifth mode.

  And the control apparatus 58 sets the content of maintenance based on the measured value and timer cleaning table after a change (step SA4). The control device 58 selects a specific maintenance mode from five maintenance modes as shown in FIGS. 11 and 15 based on the changed measurement value.

  As an example, for example, when the elapsed time t is 25 hours and the viscosity information value R obtained by the detection system 8 is 3%, the measured value t (= 25 hours) is the measured value t = t−50 ( = 0 hours). Note that, as described above, t is defined as a numerical value greater than or equal to 0, and thus is 0 hour. Since the measured value t = 0 hours corresponds to 0 hours in the timer cleaning table of FIG. 11, the first mode is set as the maintenance content (maintenance mode).

  For example, when the elapsed time t is 75 hours and the viscosity information value R obtained by the detection system 8 is 4%, the measured value t (= 75 hours) is the measured value t = t−100 (= 0 hours). Since the measured value t = 0 hours corresponds to 0 hours in the timer cleaning table of FIG. 11, the first mode is set as the maintenance content (maintenance mode).

  For example, when the elapsed time t is 75 hours and the viscosity information value R obtained by the detection system 8 is 7%, the measured value t (= 75 hours) is the measured value t = t−50 (= 25 hours). Since the measured value t = 25 hours corresponds to less than 50 hours in the timer cleaning table of FIG. 11, the second mode is set as the maintenance content (maintenance mode).

  For example, when the elapsed time t is 125 hours and the viscosity information value R obtained by the detection system 8 is 7%, the measured value t (= 125 hours) is the measured value t = t−100 (= 25 hours). Since the measured value t = 25 hours corresponds to less than 50 hours in the timer cleaning table of FIG. 11, the second mode is set as the maintenance content (maintenance mode).

  For example, when the inkjet printer 1 is not operated for a long time and the elapsed time t is 200 hours or more, the measurement value t is not changed and the maintenance mode corresponding to the viscosity information value R is executed.

  Then, the control device 58 controls the maintenance device 13 to perform maintenance processing on the ejection head 4 in the selected maintenance mode. The maintenance device 13 performs an operation (maintenance operation) for maintaining the recording head 4 in the set maintenance mode (step SA5).

  When the maintenance operation ends, a series of processes including the detection process using the detection system 8 and the maintenance process using the maintenance device 13 ends (step SA6).

  Thereafter, the control device 58 starts a recording operation on the recording paper using the recording unit 2 in the recording area.

  Here, the case where the viscosity information value R is a value related to the ratio and difference between the third time D3 and the first time D1 has been described as an example, but the ratio between the fourth time D4 and the second time D2 is described. And a value related to the difference, that is, (D2−D4) / D4. Further, the viscosity information value R may be a value related to a ratio and difference between the extreme value VPR and the extreme value VP, that is, (VP−VPR) / VPR. Further, as the viscosity information value R, (D1-D3) / D3, (D2-D4) / D4, and (VP-VPR) / VPR may be used in combination.

  As described above, according to the present embodiment, since the detection device 46 can output a detection signal corresponding to the ink ejected from the ejection port 16, the ejection is actually ejected from the ejection port 16 based on the detection signal. It is possible to quickly and accurately obtain information on the viscosity of the ink. When the maintenance process is performed by the maintenance device 13 according to the measurement value of the measurement device 61 that measures the elapsed time t from the reference time, the measurement value is calculated based on the information about the viscosity of the ink acquired by the processing device 47. By changing, appropriate maintenance processing by the maintenance device 13 can be executed. Thereby, wasteful consumption of ink can be suppressed and a good ejection state can be maintained.

  According to the present embodiment, the amount of ink discharged from the ejection port 16 during maintenance processing can be set to an optimum value. When the viscosity of the ink has not increased, the measured value can be changed and the amount of ink discharged from the ejection port 16 can be set to a small value, so that wasteful consumption of ink can be suppressed. When the viscosity of the ink is increased, the good ejection state can be recovered by changing the measurement value and setting the ejection amount of the ink ejected from the ejection port 16 to a large value.

  In this embodiment, when performing the flushing operation of step SA4, an operation of discharging a predetermined amount of ink droplets only from the ejection port 16 where the viscosity of the ink is increased with respect to the initial state can be performed, An operation of discharging ink droplets from a plurality or all of the ejection ports 16 can also be executed.

  Further, in the present embodiment, when it is determined that the viscosity of the ink has increased with respect to the initial state, when the ink droplet is ejected from the ejection port 16, the detection system 8 performs the detection operation from the ejection port 16. The size of the ink droplet ejected from the ejection port 16 in the maintenance operation by the maintenance device 13 can be increased with respect to the size of the ejected ink droplet. In order to change the size of the ink droplet, for example, the drive signal (ejection pulse DP) may be adjusted.

  Further, in the present embodiment, when the detection operation of the detection system 8 is executed, the inspection operation for each of the plurality of injection ports 16 is not executed, and only one of the plurality of injection ports 16 is detected. You may make it perform operation | movement. In addition to the ejection port 16 that performs the recording operation on the recording paper, a dedicated ejection port for performing the detection operation by the detection system 8 may be provided, and the detection operation may be performed on the ejection port.

  In the present embodiment, since the electrode member 56 is set to be a positive electrode and the nozzle substrate 21 is set to a negative electrode, the voltage value gradually increases from the second timing T2 to the third timing T3, and is detected. Although the extreme value of the signal VT is a maximum value, when the electrode member 56 is set to the negative electrode and the nozzle substrate 21 is set to the positive electrode, the voltage value is changed from the second timing T2 to the third timing T3. It gradually decreases and the extreme value of the detection signal VT becomes a minimal value. Even in this case, the processing device 47 can acquire information on the viscosity of the ink based on the detection signal.

Second Embodiment
Next, a second embodiment will be described. In the following description, the same or equivalent components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 16 is a flowchart for explaining the operation of the inkjet printer 1 according to the second embodiment. The characteristic part of the present embodiment is that the inkjet printer 1 executes an operation (reference information acquisition operation) for acquiring in advance a reference signal VPR corresponding to ink in an initial state ejected from the ejection port 16.

  In the present embodiment, for example, when the ink cartridge 48 is replaced with a new one, the reference information acquisition operation (step SA0) is executed. The detection system 8 performs a detection operation using the ink of the ink cartridge 48 immediately after the replacement. Since the ink in the ink cartridge 48 immediately after the replacement can be regarded as the ink in the initial state, the detection system 8 uses the ink to acquire information on the reference signal VR. Information about the acquired reference signal VR is stored in the storage device 60.

  After executing the reference information acquisition operation, the control device 58 commands the start of the detection operation using the detection system 8 at a predetermined timing (step SA1), as in the first embodiment described above, and the viscosity information acquisition operation. (Step SA2), the measured value is changed (step SA3), the maintenance content is set (step SA4), and the maintenance operation is executed (step SA5).

  In the first and second embodiments described above, the case where the ink jet recording apparatus is the ink jet printer 1 has been described as an example. However, the present invention is not limited to the ink jet printer, and may be a recording apparatus such as a copying machine and a facsimile. Also good.

  In each of the above-described embodiments, the case where the fluid ejecting apparatus is a liquid ejecting apparatus (liquid ejecting apparatus) that ejects a liquid (liquid material) such as ink has been described as an example. The ejecting apparatus can be applied to a fluid ejecting apparatus that ejects or discharges fluid other than ink. Fluids that can be ejected by the fluid ejecting apparatus include liquids, liquids in which particles of functional material are dispersed or dissolved, gel-like fluids, solids that can be ejected as fluids, and powders (such as toner). .

  In each of the above-described embodiments, as the liquid (liquid material) ejected from the fluid ejecting apparatus, not only ink but also a liquid corresponding to a specific application can be applied. By providing the fluid ejecting apparatus with an ejecting head capable of ejecting a liquid corresponding to the specific application, ejecting the liquid corresponding to the specific application from the ejecting head, and attaching the liquid to a predetermined object, A given device can be manufactured. For example, the liquid ejecting apparatus (liquid ejecting apparatus) according to the present invention uses a predetermined material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display (FED). The present invention is applicable to a liquid ejecting apparatus that ejects a liquid (liquid material) dispersed (dissolved) in a dispersion medium (solvent).

  In addition, the liquid ejecting apparatus may be a liquid ejecting apparatus that ejects a biological organic material used for biochip manufacturing, or a liquid ejecting apparatus that ejects a liquid that is used as a precision pipette and serves as a sample.

  In addition, transparent resin liquids such as UV curable resin to form liquid injection devices that pinpoint lubricant oil onto precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. Examples include a liquid ejecting apparatus that ejects a liquid onto a substrate, a liquid ejecting apparatus that ejects an etching solution such as acid or alkali to etch the substrate, a fluid ejecting apparatus that ejects gel, and a powder such as toner. It may be a toner jet recording apparatus that ejects a solid. The present invention can be applied to any one of these fluid ejecting apparatuses.

DESCRIPTION OF SYMBOLS 1 ... Inkjet printer (fluid ejection device), 4 ... Recording head (ejection head), 8 ... Detection system, 13 ... Maintenance device, 14 ... Capping device, 15 ... Wiping device, 16 ... Ejection port, 17 ... Ejection surface, 25 DESCRIPTION OF SYMBOLS ... Piezoelectric element (drive element), 31 ... Pressure chamber (space), 34 ... Cap member, 35 ... Suction device, 45 ... Detection part, 46 ... Detection device, 47 ... Processing device, 58 ... Control device, 60 ... Storage device 61 ... Measuring device, D1 ... 1st time, D2 ... 2nd time, D3 ... 3rd time, D4 ... 4th time, T1 ... 1st timing, T2 ... 2nd timing, T3 ... 3rd timing, T4 ... 4th timing, T5 ... 5th timing, V0 ... reference value, VP ... extreme value, VPR ... extreme value, VR ... reference signal, VT ... detection signal

Claims (1)

An ejection head having an ejection surface in which an ejection port for ejecting fluid is formed;
It has a detection part which is arranged so as to be opposed to the jetting face through a predetermined gap, and to which the fluid jetted from the jetting port is supplied, and applies an electric field between the jetting face and the detection part. And a detection device that outputs, as a detection signal , a temporal change in a voltage value based on electrostatic induction when the fluid moves from the ejection port to the detection unit,
Can perform maintenance process for discharging the fluid from the injection port of the prior SL-jet head, a maintenance device having a plurality of modes in which emissions are different from each other of the fluid discharged from the ejection port,
Viscosity information related to the viscosity of the fluid based on the difference between the maximum value of the voltage value of the reference signal output from the detection device based on the fluid before the viscosity increases and the maximum value of the voltage value of the detection signal. A fluid ejecting apparatus comprising: a control device that acquires and selects a specific mode from the plurality of modes based on the viscosity information, and controls the maintenance device in the selected mode .

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