JP2012218375A - Liquid ejection device, inspection method and program - Google Patents

Abstract

An inspection timing of a discharge unit is adjusted according to a state of the discharge unit.
A printer includes a plurality of ejection units that eject liquid, a detection unit that detects residual vibration in each ejection unit, an inspection unit that inspects the ejection unit 270 based on the residual vibration, and an inspection And an inspection setting unit 108 for setting an inspection timing for the next inspection based on the inspection result of the unit 102.
[Selection] Figure 4

Description

  The present invention relates to a technique for inspecting a discharge section in a liquid discharge apparatus.

  An ink jet printer, which is one of liquid ejection devices, includes a plurality of ejection units that eject ink. In each ejection unit, ink is stored in a cavity communicating with a nozzle, and a drive element provided in the cavity is driven. As a result, ink is ejected from the nozzles. In such a discharge unit of the liquid discharge device, when bubbles are mixed in the ink in the cavity or the ink in the cavity is thickened, the nozzle is clogged and the ink is discharged from the nozzle. There is a risk that it cannot be performed well.

  Flushing processing and suction processing are known as recovery processing (maintenance processing) for recovering the discharge portion from nozzle clogging. The flushing process is a process for removing ink in the cavity by discharging it from the nozzle, and the suction process is a process for removing the ink in the cavity by sucking from the nozzle.

  Conventionally, with regard to the recovery process of the ejection unit, a technique (for example, refer to Patent Document 1) that allows the user to select whether or not the recovery process can be automatically performed, or driving of the drive element remains in the ink in the cavity. There has been proposed a technique (for example, refer to Patent Document 2) in which a standby discharge unit is periodically inspected based on residual vibration and a recovery process is performed according to the inspection result.

JP 2003-182052 A JP 2004-299140 A

  However, conventionally, sufficient examination has not been made on the inspection time for performing the inspection of the discharge portion. For example, if the interval between inspection times is too long, there is a possibility that the discharge part cannot be maintained in a desired state. If the interval between inspection times is too short, there is a problem that the time required for inspection increases.

  In view of the above-described problems, an object of the present invention is to provide a technique capable of adjusting the inspection timing of the discharge unit according to the state of the discharge unit.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] The liquid discharge apparatus according to Application Example 1 includes a discharge unit that discharges liquid in the cavity from a nozzle communicating with the cavity by driving a driving element, and vibration of the liquid in the cavity. A detection unit that detects residual vibration remaining due to driving of the drive element, an inspection unit that inspects the ejection unit based on the residual vibration, and a next inspection by the inspection unit based on an inspection result by the inspection unit And an inspection setting unit for setting the inspection timing. According to the liquid ejection apparatus of Application Example 1, the inspection timing of the ejection unit can be adjusted according to the state of the ejection unit.

Application Example 2 In the liquid ejection apparatus according to Application Example 1, the inspection setting unit may perform the inspection timing according to a state of the ejection unit determined based on an inspection result by the inspection unit corresponding to the inspection timing. May be set. According to the liquid ejection device of Application Example 2, it is possible to adjust the inspection timing of the ejection unit based on the inspection result of the ejection unit according to the inspection timing.
Application Example 3 The liquid ejection device according to Application Example 1 or Application Example 2 further includes a maintenance unit that maintains the discharge unit based on an inspection result by the inspection unit, and the inspection setting unit is based on the maintenance unit. The inspection timing may be set in accordance with a processing amount of the maintenance unit determined based on an inspection result by the inspection unit during maintenance of the discharge unit. According to the liquid ejection device of Application Example 3, the inspection timing of the ejection unit can be adjusted based on the inspection result of the ejection unit during maintenance of the ejection unit.

  Application Example 4 The liquid ejection device according to any one of Application Example 1 to Application Example 3 further controls driving of the drive element in such a manner that the residual vibration is generated without ejecting the liquid from the ejection unit. A drive control unit may be provided. According to the liquid ejection device of the application example 4, it is possible to suppress the liquid consumption.

  Application Example 5 In the liquid ejection device according to any one of Application Examples 1 to 4, when the residual vibration is generated in the next inspection by the inspection unit based on the inspection result by the inspection unit, You may provide the discharge judgment part which judges whether the said liquid is discharged from a discharge part. According to the liquid discharge apparatus of Application Example 5, the discharge unit inspection according to the state of the discharge unit can be performed after adjusting the inspection timing of the discharge unit according to the state of the discharge unit.

  [Application Example 6] The inspection method of Application Example 6 is an inspection method for inspecting a discharge portion that discharges liquid in the cavity by driving a drive element from a nozzle communicating with the cavity. Based on a detection process for detecting residual vibration that is a vibration of liquid and remaining due to driving of the drive element, an inspection process for inspecting the discharge unit based on the residual vibration, and an inspection result by the inspection process, And an inspection setting step for setting an inspection timing for the next inspection by the inspection step. According to the inspection method of Application Example 6, it is possible to adjust the inspection timing of the discharge unit according to the state of the discharge unit.

  Application Example 7 The program of Application Example 7 is a program for causing a computer to realize a function of inspecting a discharge unit that discharges liquid in the cavity by driving a drive element from a nozzle communicating with the cavity. A detection function for detecting a residual vibration that is a vibration of the liquid in the cavity and remains due to the driving of the drive element; an inspection function for inspecting the discharge unit based on the residual vibration; and an inspection by the inspection function Based on the result, an inspection setting function for setting an inspection timing for the next inspection by the inspection function is realized. According to the program of the application example 7, the inspection timing of the discharge unit can be adjusted according to the state of the discharge unit.

  The form of the present invention is not limited to the liquid ejecting apparatus, the inspection method, and the program. In addition to the specific form of the liquid ejecting apparatus including the ink jet printer, the fluid in a state where the solid is dispersed in the liquid or gas The present invention can also be applied to other forms such as a discharge device that discharges water. Further, the present invention is not limited to the above-described embodiments, and it is needless to say that the present invention can be implemented in various forms without departing from the spirit of the present invention.

FIG. 3 is an explanatory diagram illustrating a configuration of a printer. It is explanatory drawing which shows the structure of the head in a head unit. It is explanatory drawing which shows the ink discharge mechanism in a head unit. It is explanatory drawing which shows the electrical structure of a control part and a head unit. It is explanatory drawing which shows an example of the various signals in a control part and a head unit. It is explanatory drawing which shows an example of the change of the electrical signal according to a residual vibration. It is explanatory drawing which shows an example of a mode that PP amplitude of an electric signal changes. It is explanatory drawing which shows an example of a mode that PP amplitude of an electric signal is recovered | restored by a flushing process. 6 is a flowchart illustrating standby processing executed by a control unit in a printer. It is a flowchart which shows the detail of a discharge performance test process. It is a flowchart which shows the detail of a recovery process. It is a flowchart which shows the detail of an inspection time setting process. It is explanatory drawing which shows an example of transition of the inspection time set in standby processing. It is explanatory drawing which shows an example of transition of the inspection time set in standby processing. It is explanatory drawing which shows an example of transition of the inspection time set in the standby process of 2nd Example.

  In order to further clarify the configuration and operation of the present invention described above, a liquid ejection apparatus to which the present invention is applied will be described below.

A. First embodiment:
A1. Printer configuration:
FIG. 1 is an explanatory diagram illustrating the configuration of the printer 10. The printer 10 is an ink jet printer that is one of liquid ejecting apparatuses that eject liquid, and prints data such as characters, figures, and images on a print medium 90 such as paper or a label by ejecting ink as liquid. To do. The printer 10 includes a control unit 100, a user interface 180, a communication interface 190, and a head unit 200.

  The user interface 180 of the printer 10 includes a display and operation buttons, and exchanges information with the user of the printer 10. The communication interface 190 exchanges information with an external device such as a personal computer, a digital still camera, or a memory card that can be electrically connected to the printer 10. The head unit 200 of the printer 10 includes an ink ejection mechanism that ejects ink. The details of the ink ejection mechanism will be described later.

  The control unit 100 of the printer 10 controls each unit of the printer 10. For example, the control unit 100 performs print control for ejecting ink droplets from the head unit 200 while relatively moving the head unit 200 and the print medium 90 based on data input via the communication interface 190. As a result, printing on the print medium 90 is realized.

  In this embodiment, the control unit 100 is a device including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and the like. This is realized by the CPU operating based on a computer program. Note that at least a part of the functions of the control unit 100 may be realized by an electric circuit included in the control unit 100 operating based on the circuit configuration.

  In this embodiment, the head unit 200 includes a carriage 210, an ink cartridge 220, and a head 280. The carriage 210 of the head unit 200 is connected to the control unit 100 via a flexible cable 170 and is configured to be movable in a state where the ink cartridge 220 and the head 280 are mounted. The ink cartridge 220 of the head unit 200 contains ink therein and supplies the ink to the head 280. In this embodiment, a plurality of ink cartridges 220 prepared for each ink color (four colors of black, cyan, magenta, and yellow) are mounted on the carriage 210. The head 280 of the head unit 200 is a part facing the print medium 90, and the ink supplied from the ink cartridge 220 to the head 280 is ejected from the head 280 toward the print medium 90 in the form of droplets.

  In the present embodiment, the printer 10 includes a main scanning feed mechanism and a sub-scanning feed mechanism in order to move the head unit 200 and the print medium 90 relatively. The main scanning feed mechanism of the printer 10 includes a carriage motor 312 and a driving belt 314. By transmitting the power of the carriage motor 312 to the head unit 200 via the driving belt 314, the head unit 200 is reciprocated in the main scanning direction. Let The sub-scan feed mechanism of the printer 10 includes a transport motor 322 and a platen 324, and transmits the power of the transport motor 322 to the platen 324, thereby transporting the print medium 90 in the sub-scan direction that intersects the main scan direction. The carriage motor 312 of the main scan feed mechanism and the transport motor 322 of the sub scan feed mechanism operate based on a control signal from the control unit 100.

  In the description of the present embodiment, the X axis is set as the coordinate axis along the main scanning direction in which the head unit 200 is reciprocated, the Y axis is set as the coordinate axis along the sub scanning direction in which the print medium 90 is conveyed, and the gravity direction The Z axis was set as the coordinate axis from below to above. The X axis, the Y axis, and the Z axis are coordinate axes that are orthogonal to each other.

  FIG. 2 is an explanatory diagram showing the structure of the head 280 in the head unit 200. FIG. 2 illustrates the head 280 as viewed from the print medium 90 side. The head 280 of the head unit 200 includes a plurality of nozzles 48 that eject ink. In this embodiment, n (for example, 360) nozzles 48 are provided for each ink color (four colors of black, cyan, magenta, and yellow), and the nozzles 48 for each color are in the main scanning direction (X-axis direction). Are arranged in the order of black, cyan, magenta, and yellow. The n nozzles 48 of each color are arranged so as to be shifted from each other in the sub-scanning direction (Y-axis direction). In this embodiment, the interval between the nozzles 48 in the sub-scanning direction (Y-axis direction) is narrowed. They are arranged alternately in two rows along the direction (Y-axis direction).

  In the description of this embodiment, the reference numeral “48” is used when generically referring to the nozzles in the head unit 200, the reference numeral “48k” is used when specifying a black nozzle, and the reference numeral “48” is used when specifying a cyan nozzle. 48c ", the code" 48m "is used to specify the magenta nozzle, and the code" 48y "is used to specify the yellow nozzle. Furthermore, when specifying individual nozzles, a code with a nozzle number added is used. For example, as shown in FIG. 2, the yellow first nozzle is labeled “48y (1)”, the yellow second nozzle is labeled “48y (2)”, and the yellow third nozzle is labeled. “48y (3)”,..., “48y (n−1)” is used for the (n−1) th nozzle of yellow, and “48y (n)” is used for the nth nozzle of yellow. .

  FIG. 3 is an explanatory diagram showing an ink ejection mechanism in the head unit 200. FIG. 3 shows a cross section of the head 280 cut along the direction of gravity (Z-axis direction). The ink ejection mechanism of the head unit 200 includes an introduction path 40, a reservoir 42, a supply port 44, a cavity 46, a nozzle 48, a drive element 66, and a diaphragm 67.

  The introduction path 40 and the reservoir 42 of the ink ejection mechanism are provided for each color of ink, and form a part of a flow path for flowing ink from the ink cartridge 220 to the nozzle 48. The ink supplied from the ink cartridge 220 to the head unit 200 is stored in the reservoir 42 through the introduction path 40.

  Each part of the supply port 44, the cavity 46, the drive element 66, and the vibration plate 67 in the ink discharge mechanism is provided corresponding to each of the plurality of nozzles 48 formed in the head 280, and constitutes the discharge unit 270 together with the nozzles 48. To do. That is, the head unit 200 includes a plurality of ejection units 270 corresponding to the number of nozzles 48. The ejection unit 270 ejects the ink in the cavity 46 from the nozzle 48 communicating with the cavity 46 by driving the drive element 66.

  The supply port 44 and the cavity 46 of the ejection unit 270 form part of a flow path for flowing ink from the ink cartridge 220 to the nozzle 48. The supply port 44 is a flow path that communicates between the reservoir 42 and the cavity 46, and ink is supplied from the reservoir 42 to the cavity 46 through the supply port 44. The cavity 46 is a flow path communicating with the nozzle 48, has a sufficiently larger flow path cross section than the supply port 44 and the nozzle 48, and stores ink before ejection.

  The drive element 66 of the discharge unit 270 is provided in the cavity 46 via the vibration plate 67, and the vibration plate 67 of the discharge unit 270 forms part of the flow path wall surface in the cavity 46. In this embodiment, the driving element 66 is a unimorph type piezoelectric actuator in which a piezoelectric body 664 is laminated between two electrodes 662 and 666 and a diaphragm 67 is provided on the electrode 666 side. A type piezoelectric actuator may be applied to the drive element 66. The drive element 66 bends in the direction of gravity (Z-axis direction) based on the application of the drive signal, and displaces the diaphragm 67. Thus, after the volume of the cavity 46 is expanded and ink is drawn from the reservoir 42, the volume of the cavity 46 can be reduced and ink droplets can be ejected from the nozzle 48.

  Returning to the description of FIG. 1, in this embodiment, the printer 10 includes a head wiper 330 and a head cap 340 as a maintenance mechanism (maintenance unit) that maintains the head 280 of the head unit 200. The head wiper 330 of the printer 10 removes ink attached to the head 280 by wiping off the head 280.

  The head cap 340 of the printer 10 prevents the ink from drying in the ejection unit 270 by sealing the nozzle 48 attached to the head 280 during the standby period of the head unit 200. When the nozzle 48 of the discharge unit 270 is clogged, the head cap 340 is used for recovery processing (maintenance processing) such as flushing processing and suction processing. The head cap 340 receives ink droplets discharged from the nozzles 48 of the discharge unit 270 against the head 280 in the flushing process, and sucks deteriorated ink from the nozzles 48 while attached to the head 280 in the suction process. To do. By the recovery process using the head cap 340, the discharge unit 270 clogged with ink that has deteriorated due to bubbles or thickening can be recovered to a state where ink can be appropriately discharged.

  FIG. 4 is an explanatory diagram showing the electrical configuration of the control unit 100 and the head unit 200. The control unit 100 includes an inspection unit 102, a storage unit 104, a timer 106, and an inspection setting unit 108. The head unit 200 includes a shift register 52, a latch circuit 54, a level shifter 56, and a switch 58. , Common electric circuits 62 and 68, a plurality of switches 64, and a detector 290.

  The shift register 52 of the head unit 200 is a storage device that stores instruction data that instructs the operation of each drive element 66 in the plurality of ejection units 270. In the shift input signal SI from the control unit 100, instruction data corresponding to each drive element 66 is sequentially output in synchronization with the clock signal SCK, and the shift register 52 is output based on the shift input signal SI and the clock signal SCK. The instruction data corresponding to each drive element 66 is sequentially stored. In this embodiment, the instruction data corresponding to each drive element 66 is 2-bit data, and any one of [0, 0], [0, 1], [1, 0], and [1, 1] is selected. Show.

  Based on the latch signal LAT from the control unit 100, the latch circuit 54 of the head unit 200 holds the instruction data of each drive element 66 stored in the shift register 52, and outputs a logic signal corresponding to each instruction data. Output to the shifter 56. The latch signal LAT is output from the control unit 100 at a timing when all the instruction data of each driving element 66 is stored in the shift register 52. In this embodiment, the latch circuit 54 outputs a Lo level logic signal according to the [0, 0] instruction data, and follows the Lo level according to the [0, 1] instruction data. In response to the [1,0] instruction data, the Lo level logic signal is output following the [1,0] instruction data, and the Hi level logic signal is output according to the [1,1] instruction data.

  The level shifter 56 of the head unit 200 is connected to each of the plurality of switches 64 connected to each driving element 66 in accordance with a logic signal output from the latch circuit 54, and the voltage at a level at which each switch 64 can be turned on / off. Is output. In this embodiment, the level shifter 56 outputs a voltage at a level that turns off the switch 64 in accordance with the Lo level logic signal from the latch circuit 54, and switches in accordance with the Hi level logic signal from the latch circuit 54. The voltage of the level which turns on 64 is output.

  The plurality of switches 64 in the head unit 200 turn on / off the electrical connection between the common electric circuit 62 and each driving element 66. A drive signal COM for driving the drive element 66 is input from the control unit 100 to the common electric path 62 of the head unit 200. In an ON state in which the driving element 66 is electrically connected to the common electric circuit 62 by the switch 64, the driving signal COM is applied to the electrode 662 side of the driving element 66, and the driving element 66 is electrically connected from the common electric circuit 62 by the switch 64. In the separated off state, the drive signal COM is not applied to the drive element 66. In this embodiment, the switch 64 is an analog switch using a transmission gate.

  The switch 58 of the head unit 200 connects the common electric circuit 68 electrically connected to the electrode 666 side of each drive element 66 to the ground (ground line). In this embodiment, a resistor 59 is electrically connected in parallel with the switch 58 between the common electric circuit 68 and the ground. Based on the detection execution signal DSEL output from the control unit 100, the switch 58 is While the common circuit 68 is electrically disconnected from the ground, the detection unit 290 detects the electric signal HGND output from the common circuit 68 by amplifying a voltage change based on the current flowing through the resistor 59 with an operational amplifier. Accordingly, the detection unit 290 can effectively detect the electromotive force applied from each drive element 66 to the common electric circuit 68 based on the voltage change between the electric signal HGND of the common electric circuit 68 and the ground. .

  FIG. 5 is an explanatory diagram illustrating an example of various signals in the control unit 100 and the head unit 200. FIG. 5 illustrates each time change of the latch signal LAT, the switching signal CH, the drive signal COM, and the detection execution signal DSEL in order from the upper stage, and in the lower stage, the drive element according to the instruction data of the shift input signal SI. The time change of the applied voltage applied to 66 is illustrated.

  The latch signal LAT is a logic signal that rises according to the driving cycle TD, and is input from the control unit 100 to the latch circuit 54. The drive period TD corresponds to a period in which one pixel is generated on the print medium 90 by driving the drive element 66 in each ejection unit 270.

  The switching signal CH is a signal generated in the head unit 200 based on the latch signal LAT, and is a logic signal that rises with a lapse of a specified time from the rise of the latch signal LAT. The latch circuit 54 outputs a logic signal corresponding to the first bit in the 2-bit instruction data received from the shift register 52 during the first period T1 from the rising edge of the latch signal LAT to the rising edge of the switching signal CH. During the second period T2 from the rising edge of the signal CH to the next rising edge of the latch signal LAT, a logic signal corresponding to the second bit of the instruction data is output.

  The drive signal COM is a voltage signal that is periodically output in synchronization with the drive cycle TD, and is supplied from the control unit 100 to the drive element 66 through the common electric path 62 and the switch 64. In the first period T1, the drive signal COM rises from a state in which the intermediate voltage Vc is maintained to a voltage V1 higher than the intermediate voltage Vc, then falls to a voltage V2 lower than the intermediate voltage Vc, and again returns to the intermediate voltage V1. Vc. In the subsequent second period T2, the drive signal COM rises from the intermediate voltage Vc to the voltage V1 higher than the intermediate voltage Vc, and then maintains the intermediate voltage Vc. The drive signal COM in the first period T1 is a signal of an application level that causes ink droplets to be ejected from the nozzles 48 of the ejection unit 270. The drive signal COM in the second period T2 is an application level signal that generates residual vibration without ejecting ink droplets from the nozzles 48.

  When the ejection unit 270 is inspected based on the residual vibration, the detection execution signal DSEL is detected before the second period T2 ends from the timing at which the drive signal COM returns from the voltage V1 to the intermediate voltage Vc in the second period T2. It is a logic signal that falls before the timing. When the detection execution signal DSEL falls, the switch 58 of the head unit 200 electrically disconnects the common circuit 68 from the ground, and the detection unit 290 of the head unit 200 detects the electric signal HGND of the common circuit 68.

  When the instruction data of the shift input signal SI is [0, 0], the applied voltage applied to the drive element 66 is in a state where the intermediate voltage Vc is maintained during the drive cycle TD. As a result, ink droplets are not ejected in the ejection section 270 corresponding to the drive element 66, and no residual vibration occurs. The instruction data [0, 0] of the shift input signal SI is set for the ejection unit 270 that does not form pixels at the time of printing or the ejection unit 270 that is not a target for inspection based on residual vibration.

  When the instruction data of the shift input signal SI is [0, 1], the applied voltage applied to the driving element 66 maintains the intermediate voltage Vc in the first period T1, and then rises to the voltage V1 in the second period T2. As a result, residual vibration can be generated in the ejection section 270 corresponding to the drive element 66 without ejecting ink droplets. The instruction data [0, 1] of the shift input signal SI is set for the ejection unit 270 to be subjected to the inspection based on the residual vibration when the inspection is performed without forming pixels.

  When the instruction data of the shift input signal SI is [1, 0], the applied voltage applied to the driving element 66 changes to the voltage V1 and the voltage V2 in the first period T1, and then the intermediate voltage Vc in the second period T2. Is maintained. As a result, ink droplets are ejected from the ejection section 270 corresponding to the drive element 66. The instruction data [1, 0] of the shift input signal SI is set for the ejection unit 270 that forms pixels at the time of printing.

  When the instruction data of the shift input signal SI is [1, 1], the applied voltage applied to the driving element 66 changes to the voltage V1 and the voltage V2 in the first period T1, and then to the voltage V1 in the second period T2. Change. Accordingly, it is possible to generate residual vibration suitable for the inspection of the ejection unit 270 while ejecting ink droplets in the ejection unit 270 corresponding to the drive element 66. The instruction data [1, 1] of the shift input signal SI is set for the ejection unit 270 to be subjected to the inspection based on the residual vibration when performing the inspection while forming the pixels.

  Returning to the description of FIG. 4, the detection unit 290 of the head unit 200 detects the electrical signal SW corresponding to the vibration of the ink in the cavity 46 in the ejection unit 270 and remaining due to the drive of the drive element 66. . In the present embodiment, the drive element 66 functions as a sensing unit that senses residual vibration and outputs an electric signal SW corresponding to the residual vibration, and each drive element 66 is connected to the common electric path 68 by an electromotive force associated with the residual vibration. The electrical signal SW output from is applied. Accordingly, the detection unit 290 can detect an electrical signal corresponding to the residual vibration by detecting the electrical signal HGND of the common electrical path 68. In the present embodiment, the detection unit 290 detects the electric signal HGND of the common circuit 68 based on the detection execution signal DSEL output from the control unit 100, and the detection signal POUT indicating the detection value of the residual vibration as the detection result Is output to the control unit 100.

  The inspection unit 102 of the control unit 100 inspects the ejection unit 270 based on the residual vibration detected by the detection unit 290 of the head unit 200. In the present embodiment, the inspection unit 102 inspects clogging of the nozzle 48 (ink bubble mixing and thickening) as the state of the ejection unit 270 based on the detection signal POUT output from the detection unit 290 of the head unit 200. To do. In this embodiment, the inspection of the discharge unit 270 by the inspection unit 102 is performed according to the inspection time set by the inspection setting unit 108, and the recovery of the discharge unit 270 is also confirmed during the recovery process of the discharge unit 270. To be implemented.

  The storage unit 104 of the control unit 100 stores inspection time data 130 and an evaluation reference value 140. The inspection timing data 130 in the storage unit 104 indicates the inspection timing of the next inspection by the inspection unit 102 and is updated by the inspection setting unit 108 based on the inspection result by the inspection unit 102. In this embodiment, the initial value of the inspection timing data 130 is stored in the storage unit 104 when the printer 10 is shipped from the factory. The evaluation reference value 140 of the storage unit 104 indicates a reference value related to a state quantity indicating the state of the discharge unit 270 and a reference value related to a recovery processing amount required for recovering the state of the discharge unit 270, and inspection timing data 130 by the inspection setting unit 108. Used to update In this embodiment, the evaluation reference value 140 is stored in the storage unit 104 when the printer 10 is shipped from the factory. Details of the inspection timing data 130 and the evaluation reference value 140 will be described later.

  The inspection setting unit 108 of the control unit 100 sets an inspection timing for the next inspection by the inspection unit 102 based on the inspection result of the inspection unit 102. In the present embodiment, the inspection setting unit 108 sets the next inspection time by the inspection unit 102 based on the inspection result by the inspection unit 102 according to the inspection time and the inspection result by the inspection unit 102 during the recovery process. In this embodiment, the inspection setting unit 108 sets the next inspection timing by the inspection unit 102 by updating the inspection timing data 130 in the storage unit 104.

  In the present embodiment, the inspection setting unit 108 sets the length of a waiting period until the next inspection is performed as the next inspection timing, and the inspection unit 102 performs the inspection of the discharge unit 270 when the period elapses. Do. In another embodiment, the inspection setting unit 108 sets a length of a period during which the next inspection need not be performed as the next inspection timing, and the inspection unit 102 is triggered by a predetermined condition after the period has elapsed. The discharge unit 270 may be inspected.

  The timer 106 of the control unit 100 measures (counts) time in order to manage control processing performed in the control unit 100.

  FIG. 6 is an explanatory diagram illustrating an example of a change in the electrical signal SW according to the residual vibration. In FIG. 6, the electric signals SWg, SWb, and SWv are illustrated with the voltage on the vertical axis and the time on the horizontal axis. The electric signal SWg in FIG. 6 indicates the electric signal SW corresponding to the residual vibration in the single discharge unit 270 in a state where ink can be discharged.

  Here, when the step response when the pressure P is applied to the simple vibration calculation model assuming the diaphragm 67 in the discharge unit 270 is calculated for the volume velocity u, the following Equation 1 is obtained.

  In the above formula 1, the flow path resistance r depends on the flow path shapes such as the supply port 44, the cavity 46 and the nozzle 48 and the viscosity of the ink in these flow paths, and the inertance m is the supply port 44, the cavity 46. The compliance c depends on the stretchability of the diaphragm 67, depending on the mass of the ink in the flow path such as the nozzle 48.

  The electric signal SWb in FIG. 6 indicates the electric signal SW corresponding to the residual vibration in the single ejection unit 270 in a state where the ink cannot be ejected due to the generation of bubbles in the ink in the cavity 46. When bubbles are generated in the ink in the cavity 46, the ink in the cavity 46 is reduced, and therefore the inertance m is mainly reduced. When the inertance m decreases, the angular velocity ω increases as shown in the above-described Equation 1. Therefore, as shown in FIG. 6, the oscillation cycle of the electrical signal SWb is shorter than the electrical signal SWg, and the time tf_b indicating the first half cycle in the electrical signal SWb is the time indicating the first half cycle in the electrical signal SWg. It becomes shorter than tf_g.

  The electric signal SWv in FIG. 6 indicates the electric signal SW corresponding to the residual vibration in the single discharge unit 270 in a state where the ink cannot be discharged because the ink in the cavity 46 has increased in viscosity. As the ink in the cavity 46 thickens, the flow path resistance r increases. As the flow path resistance r increases, the angular velocity ω decreases as shown in Equation 1 above. Therefore, as shown in FIG. 6, the oscillation cycle of the electrical signal SWv is longer than the electrical signal SWg, and the time tf_v indicating the first half cycle in the electrical signal SWb is the time indicating the first half cycle in the electrical signal SWg. It becomes longer than tf_g. Further, the attenuation amount of the electric signal SWv is larger than that of the electric signal Swg, and the PP amplitude Vpp indicating the difference (peak-to-peak) between the lowest amplitude of the second half cycle and the highest amplitude of the third half cycle, The PP amplitude Vpp_v of the electric signal SWv is smaller than the PP amplitude Vpp_g of the electric signal Swg.

  FIG. 7 is an explanatory diagram showing an example of how the PP amplitude Vpp of the electrical signal SW changes. FIG. 7 illustrates how the PP amplitude Vpp of the electric signal SW changes with the PP amplitude Vpp on the vertical axis and the elapsed time on the horizontal axis. The change in the PP amplitude Vpp shown in FIG. 7 is a state in which the head 280 is kept open from the head cap 340 in an environment of a temperature of 25 ° C. and a humidity of 40%.

  As shown in FIG. 7, the PP amplitude Vpp decreases with the passage of time from the opening of the head cap 340, and in particular, decreases relatively rapidly around 20 seconds after the opening of the head cap 340. The degree of decrease gradually decreases with time. The decrease in the PP amplitude Vpp is considered to be caused by the fact that the moisture of the ink in the cavity 46 is released into the atmosphere through the nozzle 48 and the viscosity of the ink in the cavity 46 increases.

  FIG. 8 is an explanatory diagram showing an example of how the PP amplitude Vpp of the electrical signal SW is recovered by the flushing process. FIG. 8 illustrates how the PP amplitude Vpp is set on the vertical axis and the number of times the flushing process is performed on the horizontal axis, and the PP amplitude Vpp of the electric signal SW is recovered from the PP amplitude Vpp_v to the PP amplitude Vpp_g by the flushing process. did. The PP amplitude Vpp_g in FIG. 8 indicates the PP amplitude of the electric signal SWg in a state where ink can be ejected, and the PP amplitude Vpp_v in FIG. 8 indicates the PP amplitude of the electric signal SWv in a state where ink is thickened.

  In the evaluation test of FIG. 8, the flushing process is repeated until the ejection unit 270 changes from the state where the ink is thickened (electric signal SWv in FIG. 6) to the state where the ink can be ejected (electric signal SWg in FIG. 6). Carried out. By repeatedly performing the flushing process, the thickened ink is discharged from the cavity 46 through the nozzle 48. Therefore, as shown in FIG. 8, the PP amplitude Vpp gradually increases from the PP amplitude Vpp_v to the PP amplitude Vpp_g. Recover. In the example of FIG. 8, the number of times of the flushing process required for recovery from the PP amplitude Vpp_v to the PP amplitude Vpp_g was 42 times.

A2. Printer behavior:
FIG. 9 is a flowchart illustrating a standby process (step S100) executed by the control unit 100 in the printer 10. The standby process (step S100) is a process for inspecting and recovering the ejection unit 270 during the standby period of the head unit 200. In the present embodiment, the standby process (step S100) is realized by the CPU of the control unit 100 operating based on a computer program. In this embodiment, the control unit 100 starts a standby process (step S100) when a predetermined time elapses after the power is turned on or the printing is completed. When a print instruction is input during the standby process (step S100), the print process is performed. In order to execute the process, the standby process (step S100) is interrupted.

  When the inspection process (step S100) is started, the control unit 100 performs control for capping the head 280 by attaching the head cap 340 to the head 280 (step S110). Specifically, the control unit 100 moves the head unit 200 to a position where it comes into contact with the head 280 of the head unit 200 after moving the head unit 200 to a position facing the head cap 340.

  After capping the head 280 (step S110), the control unit 100 sets a waiting time until the next inspection is performed as the next inspection time for inspecting the discharge unit 270 based on the inspection time data 130 in the storage unit 104. The timer count value to be counted by the timer 106 is set (step S120).

  After setting the timer count value (step S120), the control unit 100 shifts the control mode of the printer 10 to the power saving mode (step S122). In the power saving mode, the control unit 100 performs control to cut off the power supplied to each unit of the printer 10 within a range in which at least the standby process (step S100) can be continued.

  After shifting to the power saving mode (step S122), the control unit 100 starts counting by the timer 106 (step S124). Thereafter, when the timer 106 finishes counting the timer count value indicating the next inspection timing (step S126: “YES”), the control unit 100 ends the power saving mode (step S128) and operates as the inspection unit 102. Thus, the ejection performance inspection process (step S200) is executed. In the ejection performance inspection process (step S200), the control unit 100 inspects the plurality of ejection units 270 in the head unit 200 based on residual vibration.

  FIG. 10 is a flowchart showing details of the ejection performance inspection process (step S200). When the ejection performance inspection process (step S200) is started, the control unit 100 selects one of the plurality of ejection units 270 as an inspection target (step S220). After selecting the ejection unit 270 to be inspected (step S220), the control unit 100 operates as a drive control unit to drive the drive element 66 in the ejection unit 270 to be inspected (step S230).

  Specifically, the control unit 100 sets [0, 1] in the instruction data of the shift input signal SI corresponding to the ejection unit 270 to be inspected, and sets the shift input signal SI corresponding to the other ejection units 270. [0, 0] is set in the instruction data, and the latch signal LAT, the drive signal COM, and the detection execution signal DSEL are output to the head unit 200 as shown in FIG. 5 together with the shift input signal SI and the clock signal SCK. As a result, the electric signal SW corresponding to the residual vibration is applied to the common electric circuit 68 from the drive element 66 in the ejection unit 270 to be inspected. At that time, the electric signal HGND of the common electric circuit 68 detected by the detection unit 290 of the head unit 200 becomes an electric signal SW corresponding to the residual vibration in the ejection unit 270 to be inspected, and the detection unit 290 detects the detection result. A detection signal POUT indicating the detection value of the electrical signal SW is output to the control unit 100.

  After driving the drive element 66 to be inspected (step S230), the control unit 100 acquires the detection value of the electric signal SW through the detection signal POUT output from the detection unit 290 of the head unit 200 (step S240). In the present embodiment, the control unit 100 uses the time tf indicating the first half cycle in the electrical signal SW and the minimum amplitude of the second half cycle in the electrical signal SW as the detected value of the electrical signal SW corresponding to the residual vibration. A PP amplitude Vpp indicating a difference from the maximum amplitude of the three half cycles is acquired.

  After acquiring the residual vibration detection value (step S240), the control unit 100 determines the state of the ejection unit 270 to be inspected based on the detection value of the electrical signal SW (step S250). Specifically, when the time tf and the PP amplitude Vpp acquired as the residual vibration detection values are within the allowable range from the lower limit threshold value to the upper limit threshold value of each detection value, the control unit 100 determines the ejection unit 270 to be inspected. Is determined to be in a state where ink can be ejected (a state where there is no clogging). In the present embodiment, when the time tf is smaller than the lower limit threshold, the control unit 100 determines that the ink cannot be ejected due to the occurrence of bubbles in the ink (clogged state due to bubbles), and the time tf is lower than the upper limit threshold. When the value is large and the PP amplitude Vpp is smaller than the lower limit threshold, it is determined that the ink cannot be ejected because the ink is thickened (clogged state due to thickening).

  After determining the state of the ejection unit 270 to be inspected (step S250), the control unit 100 stores the determination result in the storage unit 104 (step S260). In this embodiment, the control unit 100 stores the determination result of whether or not the discharge unit 270 is clogged as a determination result. If the discharge performance of the discharge unit 270 is deteriorated due to the clogged state, the deterioration factor (bubble Mixing or thickening) and the state deterioration amount indicating the degree of deterioration of the state of the discharge unit 270 are also stored as determination results. In this embodiment, the state deterioration amount of the ejection unit 270 stored as a determination result indicates the amount of change in each value of the time tf and the PP amplitude Vpp from the state in which the ink indicated by the electrical signal SWg can be ejected.

  After storing the determination result (step S260), the control unit 100 repeatedly executes the processing from selection of the inspection target (step S220) until all of the plurality of ejection units 270 in the head 280 are inspected (step S270: "NO"). When all of the plurality of ejection units 270 in the head 280 are inspected (step S270: “YES”), the control unit 100 ends the ejection performance inspection process (step S200).

  Returning to the description of FIG. 9, after executing the discharge performance inspection process (Step S200) according to the inspection time based on the inspection time data 130, the control unit 100 restores the discharge function of the discharge unit 270 (Step S300). ) Is determined based on the inspection result of the ejection performance inspection process (step S200) (step S290). In this embodiment, the control unit 100 executes the recovery process (step S300) when at least one of the plurality of ejection units 270 in the head 280 is clogged (bubbles are mixed or thickened). In another embodiment, the control unit 100 may determine the necessity of the recovery process (step S300) according to the number of clogged ejection units 270, the deterioration factor, the setting conditions by the user, and the like.

  When it is necessary to execute the recovery process (step S300) (step S290: “YES”), the control unit 100 performs the recovery process (step S300) by operating as a maintenance unit. In the recovery process (step S300), the control unit 100 controls the flushing process and the suction process using the head cap 340.

  FIG. 11 is a flowchart showing details of the recovery process (step S300). When the recovery process (step S300) is started, the control unit 100 starts counting by the timer 106 in order to measure the time required for the recovery process (step S300) (step S310).

  Thereafter, the control unit 100 determines a deterioration factor of the discharge unit 270 in the clogged state (step S320). In this embodiment, when there are a plurality of clogged ejection units 270, the control unit 100 prioritizes the ejection units 270 having a larger state degradation amount and determines the degradation factor. When the deterioration factor of the discharge unit 270 is thickening (step S320: “(a) thickening”), the control unit 100 starts the flushing process (step S312), and the deterioration factor of the discharge unit 270 is mixed with bubbles. (Step S320: “(b) bubble”), the suction process is started (step S314).

  After starting the flushing process or the suction process (steps S312 and S314), the control unit 100 executes a discharge performance inspection process (step S320) in order to confirm the recovery status of the discharge unit 270 by the flushing process or the suction process. The details of the discharge performance inspection process (step S320) in the recovery process (step S300) are the same as the discharge performance inspection process (step S200) of FIG. 10 corresponding to the inspection time based on the inspection time data 130.

  The control unit 100 continuously performs the flushing process or the suction process until the recovery of all of the ejection units 270 determined to be clogged is confirmed based on the inspection result of the ejection performance inspection process (step S320). (Step S330: “NO”). When the recovery of all of the ejection units 270 determined to be clogged is confirmed (step S330: “YES”), the control unit 100 stops the flushing process or the suction process being executed (step S340) and the timer 106 Is stopped (step S350).

  Thereafter, the control unit 100 stores the recovery processing amount required for recovery of the ejection unit 270 determined to be clogged in the storage unit 104 as a recovery processing result (step S360). In this embodiment, the recovery processing amount stored as the recovery processing result indicates the count value counted by the timer 106 in the recovery processing (step S300).

  After saving the recovery process result (step S360), the control unit 100 ends the recovery process (step S300).

  Returning to the description of FIG. 9, when there is a need for the recovery process (step S300) (step S290: “YES”), after the recovery process (step S300) is executed, there is a need for the recovery process (step S300). If not (step S290: “NO”), after executing the ejection performance inspection process (step S200), the control unit 100 operates as the inspection setting unit 108 to execute the inspection time setting process (step S400). . In the inspection time setting process (step S400), the control unit 100 sets an inspection time for the next inspection for inspecting the discharge unit 270 based on the inspection result of the discharge unit 270.

  FIG. 12 is a flowchart showing details of the inspection timing setting process (step S400). When the inspection timing setting process (step S400) is started, the control unit 100 determines whether or not the recovery process (step S300) is performed after the ejection performance inspection process (step S200) (step S410).

  When the recovery process (step S300) is not performed (step S410: “NO”), the control unit 100 reads the reference value of the state quantity of the ejection unit 270 from the evaluation reference value 140 of the storage unit 104 (step S422). ). Thereafter, the control unit 100 calculates a state deviation amount indicating a deviation from the reference value read from the evaluation reference value 140 for the state deterioration amount of the discharge unit 270 that is the inspection result of the discharge performance inspection process (step S200) (step S200). S424).

  When the recovery process (step S300) is performed (step S410: “YES”), the control unit 100 reads the reference value of the recovery processing amount of the ejection unit 270 from the evaluation reference value 140 of the storage unit 104 (step S432). . Thereafter, the control unit 100 calculates a recovery deviation amount indicating a deviation from the reference value read from the evaluation reference value 140 for the recovery processing amount of the ejection unit 270, which is the recovery processing result of the recovery processing (step S300) (step S434). ).

  After calculating the state deviation amount or the recovery deviation amount (steps S424 and S434), the control unit 100 indicates a waiting period indicating the length of the waiting period until the next inspection is performed based on the PID calculation shown in the following equation 2. The time T is calculated as the next inspection time (step S440).

e: Deviation (state deviation or recovery deviation)
Kp: proportional constant Ki: integral constant Kd: differential constant
de / dt: Deviation change amount per unit time Ti: Integration time

  After calculating the next inspection time (step S440), the control unit 100 stores the waiting time T indicating the next inspection time as the inspection time data 130 in the storage unit 104 (step S450). As a result, the inspection timing data 130 in the storage unit 104 is updated. When the next inspection time is stored (step S450), the control unit 100 ends the inspection time setting process (step S400).

  Returning to the description of FIG. 9, after executing the inspection timing setting process (step S <b> 400), the control unit 100 ends the standby process (step S <b> 100) when the standby of the head unit 200 is ended (step S <b> 490: “ YES ”), when the standby of the head unit 200 is continued (step S490:“ NO ”), the processing from the next setting of the inspection timing for the timer 106 (step S120) is repeatedly executed.

  FIG. 13 is an explanatory diagram showing an example of the transition of the inspection timing set in the standby process (step S100). FIG. 13 illustrates the relationship between the transition of the inspection timing and the PP amplitude Vpp of the residual vibration, with the PP amplitude Vpp on the vertical axis and the time on the horizontal axis. The PP amplitude Vpp_g in FIG. 13 indicates the PP amplitude of the electric signal SWg in a state where ink can be ejected, and the PP amplitude Vpp_rv in FIG. 13 is a state quantity related to the PP amplitude stored in the storage unit 104 as the evaluation reference value 140. The reference value is shown.

  In the example shown in FIG. 13, at the start time Rcv10 of the standby process (step S100), the PP amplitude Vpp of the residual vibration has been recovered to the value of the PP amplitude Vpp_g by the recovery process (step S300). A standby time Tsb11 is set as the occasion.

  When the standby time Tsb11 elapses from the start time Rcv10, the first discharge performance inspection process (step S200) is performed (inspection time Isp11). At this inspection time point Isp11, the state deterioration amount Dm11 of the discharge unit 270 is obtained from the inspection result of the first discharge performance inspection process (step S200). At the inspection time point Isp11, the PP amplitude Vpp of the residual vibration is smaller than the start time point Rcv10, but larger than the reference value PP amplitude Vpp_rv, so the recovery process (step S300) is not performed. In the subsequent inspection timing setting process (step S400), a state deviation amount Dv11 indicating a deviation of the state deterioration amount Dm11 from the PP amplitude Vpp_rv which is the reference value is calculated, and the standby time is calculated from the state deviation amount Dv11 based on the PID calculation. Tsb12 is set. In this embodiment, the standby time Tsb12 set at the inspection time point Isp11 is longer than the standby time Tsb11 set at the start time point Rcv10.

  When the standby time Tsb12 elapses from the inspection time point Isp11, the second ejection performance inspection process (step S200) is performed (inspection time point Isp12). At this inspection time point Isp12, the state deterioration amount Dm12 of the discharge unit 270 is obtained from the inspection result of the second discharge performance inspection process (step S200). At the inspection time point Isp12, the PP amplitude Vpp of the residual vibration is smaller than the inspection time point Isp11, but is larger than the reference value PP amplitude Vpp_rv, so the recovery process (step S300) is not performed. In the subsequent inspection timing setting process (step S400), the state deviation amount Dv12 indicating the deviation of the state deterioration amount Dm12 from the PP amplitude Vpp_rv which is the reference value is calculated, and the standby time is calculated from the state deviation amount Dv12 based on the PID calculation. Tsb13 is set. In this embodiment, the standby time Tsb13 set at the inspection time point Isp12 is longer than the standby time Tsb12 set at the inspection time point Isp11.

  When the standby time Tsb13 elapses from the inspection time point Isp12, a third ejection performance inspection process (step S200) is performed (inspection time point Isp13). At this inspection time point Isp13, the state deterioration amount Dm13 of the discharge unit 270 is obtained from the inspection result of the third discharge performance inspection process (step S200). Since the PP amplitude Vpp of the residual vibration is smaller than the reference value PP amplitude Vpp_rv at the inspection time point Isp13, the recovery process (step S300) is performed.

  At the recovery time Rcv14 when the recovery process (step S300) is completed following the inspection time Isp13, the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the recovery process (step S300), and is required for the recovery. A recovery processing amount Trc14 indicating the elapsed time is obtained as a recovery processing result. In the subsequent inspection timing setting process (step S400), a recovery deviation amount Dv14 indicating a deviation of the recovery processing amount Trc14 from the recovery processing amount Trc_rv, which is the reference value, is calculated, and standby is performed from the recovery deviation amount Dv14 based on the PID calculation. Time Tsb15 is set. Note that the recovery processing amount Trc_rv indicates the reference value of the recovery processing amount stored in the storage unit 104 as the evaluation reference value 140. In this embodiment, the standby time Tsb15 set at the recovery time point Rcv14 is shorter than the standby time Tsb13 set at the test time point Isp12.

  In this embodiment, the standby time Tsb15 is calculated based on the recovery processing amount Trc14 at the recovery time point Rcv14. However, in other embodiments, the state deviation from the state deterioration amount Dm13 at the inspection time point Isp13 is similar to the inspection time points Isp11 and Isp12. The waiting time Tsb15 may be calculated by calculating the amount Dv13, or the waiting time Tsb15 may be calculated in consideration of both the recovery processing amount Trc14 and the state deviation amount Dv13.

  FIG. 14 is an explanatory diagram showing an example of the transition of the inspection timing set in the standby process (step S100). FIG. 14 illustrates the relationship between the transition of the inspection timing and the PP amplitude Vpp of the residual vibration, with the PP amplitude Vpp on the vertical axis and the time on the horizontal axis. The PP amplitude Vpp_g in FIG. 14 indicates the PP amplitude of the electric signal SWg in a state where ink can be ejected, and the PP amplitude Vpp_rv in FIG. 14 is a state quantity related to the PP amplitude stored in the storage unit 104 as the evaluation reference value 140. The reference value is shown.

  In the example shown in FIG. 14, at the start time Rcv30 of the standby process (step S100), the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the recovery process (step S300). A standby time Tsb31 is set as the occasion.

  When the standby time Tsb31 elapses from the start time Rcv30, the first ejection performance inspection process (step S200) is performed (inspection time Isp31). Since the PP amplitude Vpp of the residual vibration is smaller than the reference value PP amplitude Vpp_rv at the inspection time point Isp31, the first recovery process (step S300) is performed.

  At the recovery time Rcv32 where the recovery processing (step S300) is completed following the inspection time Isp31, the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the first recovery processing (step S300). The recovery processing amount Trc32 indicating the elapsed time required for the recovery processing is obtained as the recovery processing result. In the present embodiment, the recovery processing amount Trc32 at the recovery time point Rcv32 is larger than the recovery processing amount Trc_rv that is the reference value. In the subsequent inspection timing setting process (step S400), a recovery deviation amount Dv32 indicating a deviation of the recovery processing amount Trc32 from the recovery processing amount Trc_rv, which is the reference value, is calculated, and standby is performed from the recovery deviation amount Dv32 based on the PID calculation. Time Tsb33 is set. In the present embodiment, the standby time Tsb33 set at the recovery time Rcv32 is shorter than the standby time Tsb31 set at the start time Rcv30.

  When the standby time Tsb33 elapses from the recovery time Rcv32, the second ejection performance inspection process (step S200) is performed (inspection time Isp33). Since the PP amplitude Vpp of the residual vibration is smaller than the reference value PP amplitude Vpp_rv at the inspection time point Isp33, the second recovery process (step S300) is performed.

  At the recovery time Rcv34 when the recovery process (step S300) is completed following the inspection time Isp33, the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the second recovery process (step S300). A recovery processing amount Trc34 indicating the elapsed time required for the recovery processing is obtained as a recovery processing result. In this embodiment, the recovery processing amount Trc34 at the recovery time point Rcv34 is smaller than the recovery processing amount Trc32 at the recovery time point Rcv32, but is larger than the recovery processing amount Trc_rv that is the reference value. In the subsequent inspection timing setting process (step S400), a recovery deviation amount Dv34 indicating a deviation of the recovery processing amount Trc34 from the recovery processing amount Trc_rv, which is the reference value, is calculated, and standby is performed from the recovery deviation amount Dv34 based on the PID calculation. Time Tsb35 is set. In the present embodiment, the standby time Tsb35 set at the recovery time Rcv34 is shorter than the standby time Tsb33 set at the recovery time Rcv32.

  When the standby time Tsb35 has elapsed from the recovery time Rcv34, the third ejection performance inspection process (step S200) is performed (inspection time Isp35). Since the PP amplitude Vpp of the residual vibration is equal to the reference value PP amplitude Vpp_rv at the inspection time point Isp35, the third recovery process (step S300) is performed.

  At the recovery time Rcv36 where the recovery process (step S300) is completed following the inspection time Isp35, the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the third recovery process (step S300). A recovery processing amount Trc36 indicating the elapsed time required for the recovery processing is obtained as a recovery processing result. In this embodiment, the recovery processing amount Trc36 at the recovery time point Rcv36 is smaller than the recovery processing amount Trc34 at the recovery time point Rcv34, and is equivalent to the recovery processing amount Trc_rv that is the reference value. Therefore, the recovery deviation amount Dv36 indicating the deviation of the recovery processing amount Trc36 from the recovery processing amount Trc_rv that is the reference value becomes “0”, and the standby time Trc37 calculated in the subsequent inspection timing setting processing (step S400) is recovered. It becomes a value equivalent to the standby time Tsb35 set at the time point Rcv34.

A3. effect:
According to the printer 10 of the first embodiment described above, the inspection time setting for setting the inspection time of the next discharge performance inspection process (step S200) based on the inspection result of the discharge performance inspection process (steps S200 and S320). Since the process (step S400) is performed, the inspection timing of the discharge unit 270 can be adjusted according to the state of the discharge unit 270.

  Further, by setting the next inspection time according to the state quantity of the discharge unit 270 determined based on the inspection result of the discharge performance inspection process (step S200) performed according to the inspection time (step S424). The inspection timing of the discharge section 270 can be adjusted based on the inspection result of the discharge section 270 according to the inspection timing.

  Further, by setting the next inspection timing according to the recovery processing amount determined based on the inspection result of the ejection performance inspection processing (step S320) in the recovery processing (step S300), the recovery processing (step S434) is performed. The inspection timing of the discharge unit 270 can be adjusted based on the inspection result of the discharge performance inspection process (step S320) in step S300).

  In addition, since the drive of the drive element 66 is controlled in such a manner that residual vibration is generated without discharging ink from the discharge unit 270 (step S230), the ink consumption can be suppressed.

B. Second embodiment:
The printer 10 of the second embodiment is the same as that of the first embodiment except that the next inspection time setting method is different. In the first embodiment, when the recovery process (step S300) is performed, the next inspection time is set based on the recovery process amount, but in the second embodiment, the recovery process (step S300) is performed. Even so, the next inspection timing is set based on the state deterioration amount of the discharge unit 270.

  FIG. 15 is an explanatory diagram illustrating an example of the transition of the inspection timing set in the standby process (step S100) of the second embodiment. FIG. 15 illustrates the relationship between the transition of the inspection timing and the PP amplitude Vpp of the residual vibration, with the PP amplitude Vpp on the vertical axis and the time on the horizontal axis. The PP amplitude Vpp_g in FIG. 15 indicates the PP amplitude of the electrical signal SWg in a state where ink can be ejected, and the PP amplitude Vpp_rv in FIG. 15 is a state quantity related to the PP amplitude stored in the storage unit 104 as the evaluation reference value 140. The reference value is shown.

  In the example shown in FIG. 15, at the start time Rcv20 of the standby process (step S100), the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the recovery process (step S300). A standby time Tsb21 is set as the occasion.

  When the standby time Tsb21 elapses from the start time Rcv20, the first ejection performance inspection process (step S200) is performed (inspection time Isp21). At this inspection time point Isp21, the state deterioration amount Dm21 of the discharge unit 270 is obtained from the inspection result of the first discharge performance inspection process (step S200). Since the PP amplitude Vpp of the residual vibration is smaller than the reference value PP amplitude Vpp_rv at the inspection time point Isp21, the first recovery process (step S300) is performed.

  At the recovery time Rcv22 where the recovery process (step S300) is completed following the inspection time Isp21, the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the first recovery process (step S300). In the subsequent inspection timing setting process (step S400), a state deviation amount Dv21 indicating a deviation of the state deterioration amount Dm21 from the PP amplitude Vpp_rv which is the reference value is calculated, and the standby time is calculated from the state deviation amount Dv21 based on the PID calculation. Tsb23 is set. In this embodiment, the standby time Tsb23 set at the recovery time point Rcv22 is shorter than the standby time Tsb21 set at the start time point Rcv20.

  When the standby time Tsb23 has elapsed from the recovery time Rcv22, the second ejection performance inspection process (step S200) is performed (inspection time Isp23). At this inspection time point Isp23, the state deterioration amount Dm23 of the discharge unit 270 is obtained from the inspection result of the second discharge performance inspection process (step S200). The state deterioration amount Dm23 at the inspection time point Isp23 is smaller than the state deterioration amount Dm21 at the inspection time point Isp21. Since the PP amplitude Vpp of the residual vibration at the inspection time point Isp23 is smaller than the reference value PP amplitude Vpp_rv, the second recovery process (step S300) is performed.

  At the recovery time Rcv24 when the recovery process (step S300) is completed following the inspection time Isp23, the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the second recovery process (step S300). In the subsequent inspection timing setting process (step S400), a state deviation amount Dv23 indicating a deviation of the state deterioration amount Dm23 from the PP amplitude Vpp_rv which is the reference value is calculated, and the standby time is calculated from the state deviation amount Dv23 based on the PID calculation. Tsb25 is set. In this embodiment, the standby time Tsb25 set at the recovery time point Rcv24 is shorter than the standby time Tsb23 set at the recovery time point Rcv22.

  When the standby time Tsb25 has elapsed from the recovery time Rcv24, a third ejection performance inspection process (step S200) is performed (inspection time Isp25). At this inspection time point Isp25, the state deterioration amount Dm25 of the discharge unit 270 is obtained from the inspection result of the third discharge performance inspection process (step S200). The state deterioration amount Dm25 at the inspection time point Isp25 is smaller than the state deterioration amount Dm23 at the inspection time point Isp23. Since the PP amplitude Vpp of the residual vibration at the inspection time point Isp23 is equal to the reference value PP amplitude Vpp_rv, the third recovery process (step S300) is performed.

  At the recovery time Rcv26 where the recovery process (step S300) is completed following the inspection time Isp25, the PP amplitude Vpp of the residual vibration is recovered to the value of the PP amplitude Vpp_g by the third recovery process (step S300). Since the state deviation amount Dv25 indicating the deviation of the state deterioration amount Dm25 from the PP amplitude Vpp_rv which is the reference value is “0”, the standby time Trc27 calculated in the subsequent inspection timing setting process (step S400) is the recovery time point. It becomes a value equivalent to the standby time Tsb25 set by Rcv24.

  According to the printer 10 of the second embodiment described above, based on the inspection result of the discharge performance inspection process (step S200), the inspection time setting process (setting the inspection time of the next discharge performance inspection process (step S200)) Since step S400) is performed, the inspection timing of the discharge section 270 can be adjusted according to the state of the discharge section 270, as in the first embodiment.

C. Other embodiments:
As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, Of course, it can implement with various forms within the range which does not deviate from the meaning of this invention. is there.

  For example, in the above-described embodiment, the driving element 66 is used as a sensing unit that senses residual vibration in the ejection unit 270. However, in another embodiment, a dedicated sensor that senses residual vibration is used separately from the driving element 66. It may be applied.

  Further, the control unit 100 serves as a discharge determination unit that determines whether or not to discharge ink from the discharge unit 270 when residual vibration is generated in the next inspection by the inspection unit 102 based on the inspection result by the inspection unit 102. It may work. Accordingly, the inspection of the discharge unit 270 according to the state of the discharge unit 270 can be performed after adjusting the inspection timing of the discharge unit 270 according to the state of the discharge unit 270.

  Further, in the above-described embodiment, the residual vibration is detected by driving the drive element 66 at the application level that generates the residual vibration without discharging the ink drop. However, in other embodiments, the application level for discharging the ink drop is used. Then, the drive element 66 may be driven to detect residual vibration.

  In the above-described embodiment, the ejection performance inspection process (step S200) is performed at a timing different from that for printing on the print medium 90. However, in another embodiment, residual vibration occurs during printing on the print medium 90. The ejection unit 270 may be inspected based on the corresponding electrical signal SW.

  In the above-described embodiment, the ejection performance inspection process (step S200) is performed based on the time tf indicating the first half cycle of the residual vibration and the PP amplitude Vpp. However, in other embodiments, the period of the residual vibration, The ejection performance inspection process (step S200) may be performed based on at least one of the phase and the amplitude.

  In the above-described embodiments, the ink jet printer that ejects ink has been described as an example of the liquid ejecting apparatus. However, the liquid ejected by the liquid ejecting apparatus of the present invention is not limited to ink. It may be a fluid in which a solid is dispersed in or inside a gas. For example, the present invention is not limited to an ink jet printer, and can be applied to other printers. Also used in the manufacture of liquid crystal displays, organic EL (Electro Luminescence) displays, and surface emission displays (Field Emission Displays, FEDs), etc., and liquid materials containing materials such as electrode materials and color materials in a dispersed or dissolved state. The present invention can also be applied to a discharge device that discharges. Further, the present invention can be applied to a discharge device that is used for manufacturing a biochip and discharges a liquid containing a biological organic material. Further, it can be applied to a discharge device that is used as a precision pipette and discharges a liquid as a sample. Transparent resins such as ultraviolet curable resins are used to form a dispensing device that dispenses lubricant oil to precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. The present invention can also be applied to a discharge device that discharges liquid. Further, the present invention can be applied to a discharge device that discharges an etching solution for etching a wafer or a discharge device that discharges powder such as toner.

DESCRIPTION OF SYMBOLS 10 ... Printer 40 ... Introduction path 42 ... Reservoir 44 ... Supply port 46 ... Cavity 48, 48k, 48c, 48m, 48y ... Nozzle 52 ... Shift register 54 ... Latch circuit 56 ... Level shifter 58 ... Switch 59 ... Resistor 62 ... Common Electrical path 64 ... Switch 66 ... Drive element 67 ... Vibrating plate 68 ... Common electrical circuit 90 ... Print medium 100 ... Control unit 102 ... Inspection unit 104 ... Storage unit 106 ... Timer 108 ... Inspection setting unit 130 ... Inspection timing data 140 ... Evaluation reference value DESCRIPTION OF SYMBOLS 170 ... Flexible cable 180 ... User interface 190 ... Communication interface 200 ... Head unit 210 ... Carriage 220 ... Ink cartridge 270 ... Discharge part 280 ... Head 290 ... Detection part 312 ... Carriage motor 314 ... Drive belt 32 ... conveying motor 324 ... platen 330 ... head wiper 340 ... head cap 662 ... electrode 664 ... piezoelectric 666 ... electrode

Claims (7)

A discharge section that discharges the liquid in the cavity from the nozzle communicating with the cavity by driving a drive element;
A detection unit for detecting a residual vibration caused by driving of the driving element, which is vibration of the liquid in the cavity;
An inspection unit for inspecting the discharge unit based on the residual vibration;
A liquid ejection apparatus comprising: an inspection setting unit that sets an inspection timing for a next inspection by the inspection unit based on an inspection result by the inspection unit.   The liquid ejection device according to claim 1, wherein the inspection setting unit sets the inspection time according to a state of the discharge unit determined based on an inspection result by the inspection unit according to the inspection time. The liquid ejection device according to claim 1 or 2, wherein
Furthermore, a maintenance part for maintaining the discharge part based on the inspection result by the inspection part is provided,
The liquid ejection apparatus, wherein the inspection setting unit sets the inspection time according to a processing amount of the maintenance unit determined based on an inspection result by the inspection unit during maintenance of the discharge unit by the maintenance unit.   The liquid according to any one of claims 1 to 3, further comprising a drive control unit that controls driving of the drive element in a manner that generates the residual vibration without discharging the liquid from the discharge unit. Discharge device.   And a discharge determination unit configured to determine whether or not to discharge the liquid from the discharge unit when the residual vibration is generated in the next inspection by the inspection unit based on the inspection result of the inspection unit. The liquid ejection apparatus according to claim 1. An inspection method for inspecting a discharge part that discharges the liquid in the cavity by driving a drive element from a nozzle communicating with the cavity,
A detection step of detecting residual vibrations due to the vibration of the liquid in the cavity and remaining due to the driving of the driving element;
An inspection step of inspecting the discharge unit based on the residual vibration;
An inspection setting step of setting an inspection timing for a next inspection by the inspection step based on an inspection result by the inspection step. A program for causing a computer to realize a function of inspecting a discharge unit that discharges liquid in the cavity by driving a drive element from a nozzle communicating with the cavity,
A detection function for detecting residual vibration which is vibration of the liquid in the cavity and remains due to driving of the driving element;
An inspection function for inspecting the discharge unit based on the residual vibration;
A program for realizing an inspection setting function for setting an inspection timing for a next inspection by the inspection function based on an inspection result by the inspection function.

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