JP2012236300A - Fluid discharging device, method and program for inspecting nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce nozzles to which a maintenance process is undone after a nozzle inspection, and which lapse into an unstable state.SOLUTION: The fluid discharging device includes: a discharge head (24) for discharging a fluid (FL1) from the nozzle 23; a nozzle inspection unit U1 for inspecting a discharging state of the fluid (FL1) discharged from the nozzle 23; and a control unit U2 that executes a flushing process of making the nozzle 23 discharge a fluid (FL2) therefrom for flushing before an inspection process when executing the inspection process by the nozzle inspection unit U1 while discharging a fluid (FL3) from the nozzle 23.

Description

  The present invention relates to a fluid ejection device that ejects fluid from a nozzle, a nozzle inspection method, and a nozzle inspection program.

A fluid ejecting apparatus such as an ink jet printer inspects a nozzle based on a voltage change caused by ink ejected from the nozzle, and executes a recovery process such as a cleaning process as maintenance when the nozzle is clogged. The reason why ink is not ejected normally from the nozzles is that the surface of the ink (meniscus) exposed to the nozzles is exposed to the atmosphere, causing the solvent to evaporate and the ink to thicken or bubbles to enter the pressure generation chamber. It is mentioned that the pressure change in the pressure generating chamber is absorbed by the bubbles. For this reason, when a nozzle that does not eject ink normally is detected in the ejection inspection process, a recovery process is performed on the nozzle in order to recover to a normal state.
For example, in the fluid ejection device described in Patent Document 1, a cleaning box is provided in one-to-one correspondence with a plurality of nozzle rows, electrodes are arranged in each cleaning box, and voltage changes due to fluid ejected from the nozzles. It is determined whether or not the fluid has been discharged by switching the electrode connected to the detection means. A cleaning process is performed on the nozzle rows that are determined not to have ejected fluid.

  Even if the recovery process is executed, the pressure fluctuation during maintenance cannot be sufficiently applied to very small bubbles (for example, bubbles with a diameter of several tens of μm), and it is difficult to remove them completely. is there. Therefore, the liquid ejection device described in Patent Document 2 performs a flushing operation for repeatedly ejecting ink after performing a cleaning process so that bubbles remaining in the ejection head are discharged together with the ink. In this flushing operation, an attempt has been made to increase the pressure difference per unit time by increasing the drive voltage (potential difference from the highest potential to the lowest potential) of the flushing drive pulse applied to the piezoelectric element to the maximum.

JP 2009-226616 A JP 2010-167684 A

  When the state of the nozzle is not normal, there are clogged states in which the fluid is not discharged from the nozzle, and unstable states such as an unstable fluid discharge direction and a reduced fluid discharge amount. If an electrical change such as a voltage change due to the fluid discharged from the nozzle exceeds the threshold value, the unstable nozzle is determined to be normal and maintenance is not performed, and the unstable nozzle is used for printing. In some cases, the print image quality may deteriorate.

  In view of the above, one of the objects of the present invention is to reduce the number of unstable nozzles that are not maintained after nozzle inspection.

Means for solving the problems and their actions and effects

In order to achieve one of the above objects, the present invention provides a discharge head capable of discharging a fluid from a nozzle,
A nozzle inspection unit for inspecting the discharge state of the fluid from the nozzle;
When performing the inspection process by the nozzle inspection unit by discharging the fluid from the nozzle, a control unit that performs the inspection process after performing the flushing process of discharging the fluid for flushing from the nozzle;
It is set as one of the aspects to provide.

  That is, since the flushing process is performed before the inspection process, the unstable nozzle can be brought into a normal state by the flushing process. Therefore, this aspect can reduce the number of unstable nozzles that are not maintained after nozzle inspection, and can suppress the use of unstable nozzles for printing.

Here, for example, the fluid ejection device may be provided in a single printer, or may be provided across the printer and an external device.
The inspection of the fluid discharge state includes detecting whether the nozzle is in a normal state, detecting whether the nozzle is in a normal state, a clogged state, or an unstable state, etc. It is.

By the way, the control unit may execute the flushing process and the inspection process again when a missing dot is detected by the inspection process. The time from the end of the flushing process to the start of the inspection process is made equal in the case of the first inspection process after print data is acquired and in the case of the inspection process executed again. Also good. This aspect can provide a suitable configuration for maintenance.
The ejection head may include a drive element that ejects fluid from the nozzle in accordance with a drive pulse. The controller discharges fluid for flushing from the nozzle by causing the drive element to supply a drive pulse for flushing that is different from a drive pulse for recording used for fluid ejection to a recording medium during the flushing process. You may let them. Since the fluid is ejected from the nozzles according to the flushing drive pulse different from the recording drive pulse, this aspect can provide a suitable configuration that reduces the number of unstable nozzles that are not maintained after nozzle inspection.
Furthermore, the drive frequency of the flushing drive pulse may be lower than the drive frequency of the recording drive pulse. The speed of the fluid ejected from the nozzle according to the flushing drive pulse may be made slower than the speed of the fluid ejected from the nozzle according to the recording drive pulse. These aspects can provide a suitable configuration that further reduces the number of unstable nozzles that are not maintained after nozzle inspection. On the other hand, although such an aspect is preferable, even if the flushing drive pulse is the same as the recording drive pulse, an effect of reducing the number of unstable nozzles that are not maintained after nozzle inspection can be obtained.

  When the ejection head includes a plurality of the nozzles, the time from the end of the flushing process to the start of the inspection process may be equalized for each of the nozzles. Since the time from the end of the flushing process to the execution of the inspection process is equalized for each nozzle, this aspect can provide a suitable configuration that reduces the number of unstable nozzles that are not maintained after the nozzle inspection.

  The control unit may execute the inspection process for the first nozzle and the flushing process for the second nozzle in parallel. Since the inspection process for the first nozzle and the flushing process for the second nozzle are executed in parallel, this aspect can quickly perform the nozzle inspection.

  When the discharge head includes at least a first and a second nozzle group that is a maintenance execution unit, the control unit performs the inspection process for the first nozzle included in the first nozzle group and the The flushing process for the second nozzle included in the second nozzle group may be executed in parallel. Since the inspection process and the flushing process are executed in parallel in the nozzle groups of the execution units having different maintenance, this aspect can perform the nozzle inspection quickly.

  The control unit may execute the inspection process after performing the flushing process for the second nozzle after performing the inspection process after performing the flushing process for the first nozzle. Since a series of processes of the flushing process and the inspection process is performed for the second nozzle after the series of processes of the flushing process and the inspection process for the first nozzle is finished, this mode is unstable that is not maintained after the nozzle inspection. A suitable configuration for reducing the number of nozzles in the state can be provided.

  The above-described aspects include a nozzle inspection apparatus, a printing apparatus, a print control apparatus, a system including these apparatuses, a nozzle inspection method including a process such as a control process, a fluid ejection method, a printing method, a print control method, and a function such as a control function. The present invention is applicable to a nozzle inspection program, a fluid ejection program, a printing program, a printing control program, a computer-readable medium on which these programs are recorded, and the like.

The figure which illustrates typically the concept of a nozzle inspection method. 1 is a diagram illustrating an outline of a configuration of a printer 20 to which a fluid ejection device according to an embodiment of the invention is applied. FIG. 3 is a diagram schematically illustrating an electrical connection of a print head 24. (A) is a cross-sectional view illustrating an outline of the configuration of the print head 24, (b) is a diagram illustrating a flushing drive pulse P1 supplied to the drive element 48, and (c) is a recording supplied to the drive element 48. The figure which illustrates the drive pulse P2 for an object. 2 is a diagram illustrating an outline of a configuration of a printer. FIG. (A)-(c) is a figure which illustrates typically the mechanism of the bubble removal by bubble removal flushing. The flowchart which illustrates a nozzle test process. 9 is a flowchart illustrating a flushing + nozzle determination process. 6 is a flowchart illustrating processing when printing is executed. (A)-(d) is a figure which illustrates the sequence of the flushing process for every nozzle, and a nozzle determination process. FIG. 9 is a diagram illustrating an outline of a configuration of a printer 20 according to a modification. The flowchart which shows the flushing + nozzle determination process which concerns on a modification. The flowchart which shows the flushing + nozzle determination process which concerns on another modification. 9 is a flowchart illustrating processing at the time of executing printing according to a comparative example.

(1) Outline of nozzle inspection method:
First, an outline of a nozzle inspection method according to an aspect of the present invention will be described with reference to FIGS.
2 and 5 schematically show the configuration of an ink jet printer 20 to which a fluid ejection device according to an embodiment of the present invention is applied. The printer 20 includes a print head (discharge head) 24 and a nozzle inspection device 50 shown in FIG. The print head 24 can eject ink (fluid) FL <b> 1 from each nozzle 23 included in the nozzle row (nozzle group) 43. The nozzle inspection unit U1 included in the nozzle inspection device 50 inspects the ejection state of the ink FL1 from the nozzle 23. For example, the nozzle inspection unit U1 detects a voltage change (electrical change) due to the ink FL1 ejected from the nozzle 23, and compares the detected voltage change with the threshold value Vref to determine whether the state of the nozzle 23 is normal. Determine whether or not. The control unit U2 included in the nozzle inspection device 50 discharges the ink FL3 from the nozzle 23 and executes inspection processing by the nozzle inspection unit U1. At this time, the control unit U2 performs the inspection process after performing the flushing process of ejecting the ink FL2 from the nozzle 23 for the flushing. This flushing process can also be said to be a process of discharging the thickened ink from the nozzles and converting the meniscus of the nozzles into a meniscus having a shape suitable for nozzle inspection.

  When the state of the nozzle 23 is not normal, there is an unstable state in addition to a clogged state. Here, the clogged state is a state where ink droplets are not ejected from the nozzles, and a so-called dot dropout occurs. The unstable state means a state where the ink droplets are ejected from the nozzles, but the flying direction and ejection amount of the ink droplets are abnormal. For example, there is an abnormal ejection state in which ink droplets are bent without flying perpendicular to the printing surface, ink droplets are scattered in multiple directions from one nozzle, or the amount of ejected ink is reduced. . Possible causes of the unstable state include the occurrence of mist of ejected ink and adhesion to the nozzle surface, and the entry of minute bubbles into the nozzle.

  In the upper part of FIG. 1, the nozzles 231 and 232 in the “missing” state (clogged state), the nozzle 233 in the “bent” state (unstable state), and the nozzle 234 in the “thinning” state (unstable state) are generated. A print head 24 is illustrated. When the nozzle inspection is performed without flushing as in the past, the unstable nozzles 233 and 234 may be determined to be normal because they are not clogged. In this case, when printing on recording paper, the dots of ink droplets ejected from the nozzles 233 and 234 in an unstable state may deteriorate the print image quality. As shown in the middle part of FIG. 1, the fluid ejection device executes a flushing process such as bubble removal flushing immediately before the nozzle inspection. As a result, the nozzle 233 in the “bent” state is restored to the normal state, the nozzle 234 in the “thin” state is restored to the normal state, and a part of the nozzles in the “missed” state (nozzle 231) Can be restored to a normal state. Therefore, in the nozzle inspection after the flushing process, as illustrated in the lower part of FIG. 1, even if the nozzles 233 and 234 that are in an unstable state are determined to be in a normal state, they are actually changed to a normal state. Even if the nozzle 231 in the clogged state is determined to be in the normal state, it actually changes to the normal state. Of course, if the nozzle 232 in the “missed” state remains, maintenance processing such as cleaning is executed.

  As described above, in this nozzle inspection method, since the flushing process is performed before the inspection process, the unstable nozzle can be made normal by this flushing process, and the unstable nozzle is used for printing. Can be prevented. Therefore, this nozzle inspection method can reduce the number of unstable nozzles that are not maintained after nozzle inspection.

(2) Printer configuration:
The printer 20 illustrated in FIG. 2 includes a paper feed mechanism 31, a printer mechanism 21, a capping device 40, a nozzle inspection unit U1, a controller 70, an operation panel 79, and the like shown in FIG. The paper feeding mechanism 31 conveys the recording medium M1, such as recording paper, in the conveying direction DR2 by driving the paper feeding roller 35 by the driving motor 33.

  The printer mechanism 21 includes a carriage motor 34 a, a driven roller 34 b, a carriage belt 32, a carriage 22, an ink cartridge 26, a print head (discharge head) 24, and the like, and a recording medium conveyed on a platen 38 by a paper feed mechanism 31. Printing is performed by ejecting ink droplets from the print head 24 to M1. The carriage motor 34 a is disposed on the opposite side of the capping device 40 with respect to the mechanical frame 80. The driven roller 34 b is disposed on the capping device 40 side with respect to the mechanical frame 80. The carriage belt 32 is installed on a carriage motor 34a and a driven roller 34b. The carriage 22 reciprocates in the main scanning direction DR1 along the guide 28 by the carriage belt 32 as the carriage motor 34a is driven. The ink cartridge 26 individually accommodates yellow (Y), magenta (M), cyan (C), and black (K) inks containing a colorant such as a dye or pigment in water (solvent) and is mounted on the carriage 22. Has been. A linear encoder 36 for detecting the position of the carriage 22 is disposed on the rear surface of the carriage 22, and the position of the carriage 22 is managed by the linear encoder 36.

  The print head 24 illustrated in FIGS. 3 and 4 includes a nozzle plate 27, a cavity plate 25, a diaphragm 49, a drive element 48, a drive pulse generation circuit 47, and a temperature detection unit 24t. The nozzle plate 27 is made of stainless steel or the like, and a nozzle row 43 in which a plurality of nozzles 23 are arranged in the transport direction DR2 is formed. In the example of FIG. 3, a plurality of nozzle rows 43C, 43M, 43Y, and 43K in which 180 C, M, Y, and K nozzles 23C, 23M, 23Y, and 23K are arranged in one row for each color are shown. ing. Each nozzle 23 is a small through-hole having a tapered portion 23t whose diameter gradually decreases from the pressure chamber 44b toward the nozzle surface 27a. The cavity plate 25 forms an ink chamber (44a, 44b) communicating with the nozzle 23 together with the nozzle plate 27 and the vibration plate 49. The common ink chamber 44a communicates with the pressure chamber 44b by the ink flow path 44c, functions as an ink buffer region for the pressure chamber 44b, and sends ink filled from the ink cartridge 26 to the pressure chamber 44b. The driving element 48 may be a piezoelectric element such as a piezo element, an electrostatic driving element, a heater that discharges a fluid from a nozzle using the pressure of bubbles caused by film boiling by heating ink, and the like. The drive element 48 shown in FIG. 4 is bonded to the opposite side of the diaphragm 49 from the cavity plate 25, and ejects ink from the nozzles 23 in accordance with the supplied drive pulse. The piezoelectric element that can be used for the drive element 48 is made of ceramic such as zirconia ceramic. The drive pulse generation circuit 47 is a drive circuit that is formed on the head drive substrate 30 and outputs a drive signal to the drive element 48. Under the control of the controller 70, the print head 24 applies a voltage from the drive pulse generation circuit 47 to the drive element 48, presses the upper wall of the pressure chamber 44b with the drive element 48, pressurizes the ink, and ejects ink droplets. . The temperature detection unit 24 t provided in the print head 24 is configured by, for example, a temperature sensor, detects the operating environment temperature of the print head 24, and transmits the detection signal to the controller 70.

The drive element 48 illustrated in FIG. 4 is a stacked piezoelectric vibrator that is configured by alternately stacking piezoelectric bodies and internal electrodes, and in the vertical direction orthogonal to the stacking direction according to the applied voltage ( A piezoelectric vibrator in a longitudinal vibration mode that can be expanded and contracted (illustrated by arrows). The fixing base 44d for fixing the driving element 48 is formed of a member having sufficient rigidity to efficiently transmit the vibration of the driving element 48 to the diaphragm 49. The vibration plate 49 is a plate-like member having a thick portion with which the drive element 48 abuts and a thin portion having elasticity on the outer periphery thereof, and the thick portion vibrates according to the expansion and contraction of the drive element 48.
Of course, the drive element may be a transverse vibration mode piezoelectric element in which a common upper electrode, a drive electrode, and a common lower electrode are stacked.

  The drive pulse generation circuit 47 illustrated in FIG. 3 receives the original signal ODRV and the print signal PRTn generated by the original signal generation circuit 60, generates the drive signal DRVn based on these signals ODRV and PRTn, and drives the drive signal DRVn. Output to the element 48. “N” at the end of the signal PRTn and the signal DRVn is a number for specifying a nozzle included in the nozzle row. The original signal generation circuit 60 outputs a signal having a predetermined pulse as a repeating unit to the drive pulse generation circuit 47. The drive pulse generation circuit 47 generates a drive signal DRVn based on the original signal ODRV and the separately input print signal PRTn, and outputs it to the drive element 48. For example, when a pulse-like drive signal DRVn having a relatively small potential difference is output to the drive element 48, one shot of ink droplets is ejected from the nozzle 23 to form a small dot on the recording medium M1, thereby setting an intermediate potential difference. When the pulsed drive signal DRVn is output to the drive element 48, one shot of ink droplets is ejected from the nozzles 23 to form medium dots on the recording medium M1, and the pulsed drive signal DRVn having a relatively large potential difference is driven. When output to the element 48, one shot of ink droplet is ejected from the nozzle 23 to form a large dot on the recording medium M1.

  A capping device 40 illustrated in FIG. 5 includes a cap 41, a suction pump 45, an air release valve 46, and an elevating device 90, and is provided at a position facing a home position serving as one end of the platen 38. The cap 41 is a substantially rectangular parallelepiped or the like, and the upper part is open. The suction pump 45 is attached to a stretchable tube 45 a connected to the bottom of the cap 41. The air release valve 46 is attached to a stretchable tube 46 a connected to the bottom of the cap 41. The elevating device 90 elevates and lowers the cap 41 in order to make contact between the upper surface of the cap 41 and the surface of the nozzle plate 27 and release thereof. The capping device 40 raises the cap 41 in a state where the print head 24 is moved to the home position facing the capping device 40 during a printing pause in order to suppress thickening (drying) of the ink in the nozzles 23. The nozzle plate 27 is sealed. Further, the capping device 40 closes the atmosphere release valve 46 with the nozzle plate 27 sealed at a predetermined timing, and drives the suction pump 45 to thereby remove the internal space formed by the print head 24 and the cap 41. The ink in the nozzle 23 is forcibly sucked with a negative pressure. This process is called cleaning.

5 includes an electrode 52, a voltage application circuit 54, a voltage detection circuit 56, a comparison circuit 57, and the like.
The electrode 52 is disposed in the cap 41. The electrode 52 can be made of mesh-like stainless steel or the like. On the upper side of the electrode 52, an ink absorber (for example, a conductive sponge) on which ink droplets land may be provided. An ink absorber (for example, a nonwoven fabric such as felt) that absorbs ink that has permeated downward may be provided below the electrode 52. The nozzle inspection unit U1 detects a voltage change ΔV1 generated in the electrode 52 when the ink droplet (FL1) lands on the cap 41 by discharging the ink droplet (FL1) charged from the nozzle 23 into the cap 41. Then, it is determined whether or not the ink droplet (FL1) is normally ejected from the nozzle 23.

  The voltage application circuit 54 includes a resistance circuit R1 (for example, 1 MΩ), which is a high-voltage power source Ve obtained by boosting a voltage of several volt electrical wiring routed inside the printer 20 to a DC voltage of several hundred volts or several thousand volts by a boost circuit. Are connected to the electrode 52 through the switch SW1 and the switch SW1 in this order. When the switch SW1 is turned on, the electrode 52 and the high voltage power source Ve can be connected, and when the switch SW1 is turned off, the high voltage power source Ve can be disconnected from the electrode 52 and grounded. On the other hand, the nozzle plate 27 of the print head 24 is grounded together with the mechanical frame 80. Therefore, a potential difference is generated between the nozzle plate 27 and the electrode 52 when the switch SW1 is on.

  The voltage detection circuit 56 is connected to the electrode 52 and is a circuit for detecting a voltage change generated at the electrode 52. The voltage change to be detected can be the difference between the highest voltage and the lowest voltage of the voltage signal input to the voltage detection circuit 56. The voltage detection circuit 56 may convert an input analog voltage into a digital value by an A / D converter (analog-digital converter). In order to increase the voltage change generated at the electrode 52 when the charged ink droplets land on the cap 41, the peak value of the voltage waveform generated at the electrode 52 is extracted and held, and the held peak value is integrated, The integrated voltage signal may be amplified. Such an amplified signal is also included in the voltage change (electrical change) ΔV1 of the present technology.

  The comparison circuit 57 inputs a threshold value Vref for comparison with the voltage change ΔV1 detected by the voltage detection circuit 56 from the controller 70 and holds it. Then, the voltage change ΔV1 is compared with the threshold value Vref, and when the voltage change ΔV1 is higher than the threshold value Vref (on the higher side from the threshold value Vref), the determination signal (contrast result) Vout of the high level H is sent to the controller 70. When the voltage change ΔV1 is lower than the threshold value Vref (on the lower side from the threshold value Vref), the determination signal (contrast result) Vout of the low level L is output to the controller 70. Here, the fact that the voltage change ΔV1 is higher than the threshold value Vref includes both that the voltage change ΔV1 is greater than or equal to the threshold value Vref and that the voltage change ΔV1 is larger than the threshold value Vref. That the voltage change ΔV1 is lower than the threshold value Vref includes both that the voltage change ΔV1 is equal to or less than the threshold value Vref and that the voltage change ΔV1 is smaller than the threshold value Vref. Further, the threshold value may be an object to be compared with an electrical change such as a detected voltage change. When the detected electrical change is represented by a digital value, the threshold value of the digital value is detected. The threshold value of the gradation value is represented by a gradation value, and the analog threshold value is represented when the detected electrical change is represented by an analog such as a voltage state.

  The comparison circuit 57 stores the threshold value Vref in the threshold value register, compares the digital value of the voltage change ΔV1 with the threshold value Vref of the threshold value register, and stores the comparison result (contrast result) in the comparison result register. The comparison result in the comparison result register may be output to the controller 70 as the determination signal Vout. The comparison result may be, for example, “1” representing H when the digital value of the voltage change is higher than the threshold value Vref, and “0” representing L when the digital value of the voltage change is lower than the threshold value Vref.

  The voltage change ΔV1 generated in the electrode 52 is smaller when ink droplets are not ejected from the nozzle 23 or smaller than usual, compared to when ink droplets are ejected normally. Therefore, it is possible to determine whether or not the state of the nozzle 23 is normal by setting a threshold Vref that distinguishes this.

2 and 5 includes a CPU (Central Processing Unit) 72, a ROM (Read Only Memory) 73, a RAM (Random Access Memory) 74, a non-volatile memory 75, an I / F (interface) 76, an input / output. A port and the like are provided to control the entire printer 20. The ROM 73 stores various processing programs including a nozzle inspection program. This nozzle inspection program causes the controller 70, which is a computer, to function as the control unit U2. The nozzle inspection program may be recorded on a computer-readable external recording medium. The RAM 74 is provided with a print buffer area, and temporarily stores print data sent from the host apparatus 10 via the I / F 76 in this print buffer area. As the non-volatile memory 75, a flash memory or the like can be used. The I / F 76 inputs a print job from the host device 10 and outputs print status information and the like to the host device 10. A determination signal Vout from the comparison circuit 57, a position signal of the carriage 22 from the linear encoder 36, and the like are input to the input port. The controller 70 includes a control signal to the print head 24 including the drive pulse generation circuit 47 and the drive element 48, a switch signal to the switch SW1, a control signal to the original signal generation circuit 60, a drive signal to the drive motor 33, and a carriage motor. A drive signal to 34a, a drive signal to the lifting device 90, a threshold value Vref, and the like are output from the output port. The controller 70 forms a control unit U2 together with the original signal generation circuit 60.
The host device 10 may be a computer such as a personal computer, a digital camera, a digital video camera, a mobile phone, or the like.

(3) Explanation of flushing process:
In the flushing process, the ink is ejected from the nozzles 23 and air bubbles and thickened ink are ejected from the nozzles 23 together with the ink droplets. “Empty ejection” means the original use of ink droplets, that is, ejection performed for purposes other than printing. When executing the flushing, the controller 70 moves the print head 24 to the home position, and keeps the cap 41 away from the nozzle surface 27a. The idle discharge is repeatedly performed a predetermined number of times. The continuous ink droplet ejection process is referred to as a continuous flushing set.
Among the flushing operations, in the bubble removal flushing for the purpose of removing bubbles in particular, a driving pulse P1 for flushing different from the recording drive pulse P2 used for fluid ejection to the recording medium M1 is supplied to the drive element 48. Thus, the ink FL2 is ejected from the nozzle 23. The bubble removal flushing is repeated a predetermined number of times. This will be referred to as an open bubble removal flushing set.

  Before executing the continuous flushing set, the temperature detection unit 24t detects the environmental temperature of the print head 24, and controls the ink discharge amount from the nozzles to be substantially constant according to the environmental temperature, or according to the environmental temperature. The number of discharges may be changed. When the ink discharge amount increases as the environmental temperature increases, the ink discharge amount may be controlled so as to subtract the increase amount of the ink discharge amount due to the increase in the environmental temperature. Further, the discharge count of the continuous flushing set may be increased as the environmental temperature becomes higher.

FIG. 4B illustrates the flushing drive pulse P1 supplied to the drive element 48 when the bubble removal flushing is executed. FIG. 4C illustrates the recording drive pulse P2 supplied to the drive element 48 when performing normal printing. 4B and 4C, the horizontal axis represents time, and the vertical axis represents voltage.
The flushing drive pulse P1 shown in FIG. 4B has an ascending pulse portion Pwc, a descending pulse portion Pwd, and an intermediate pulse portion Pwh between the two pulse portions Pwc and pwd. In the rising pulse portion Pwc, the voltage value of the drive element 48 increases at a constant rate from the ground state (for example, voltage value 0) to the peak voltage value (V1) between time t0 and time t1. V1 is a kind of drive voltage of the flushing drive pulse P1, and is a potential difference between the highest potential and the lowest potential in the flushing drive pulse P1. In the intermediate pulse portion Pwh, the voltage value of the driving element 48 is kept constant at the peak voltage value (V1) from time t1 to time t2. The falling pulse portion Pwd is a portion in which the voltage value of the driving element 48 returns from the peak voltage value (V1) to the ground state at a constant ratio between time t2 and time t3, and is a period during which ink droplets are ejected. In order to repeatedly eject ink droplets from the nozzle 23 a predetermined number of times, the flushing drive pulse P1 is supplied to the drive element 48 repeatedly a predetermined number of times.
The recording drive pulse P2 shown in FIG. 4C includes a rising pulse portion (time t10 to t11), a peak portion (time t11 to t12), a falling pulse portion (time t12 to t13), and a bottom portion (time t13 to t14). ) And a return portion (time t14 to t15). In order to repeatedly eject ink droplets from the nozzle 23 a predetermined number of times, the recording drive pulse P2 is supplied to the drive element 48 repeatedly a predetermined number of times.

The period T1 of the flushing drive pulse P1 in the continuous bubble removal flushing set is characterized in that it is longer than the period T2 of the recording drive pulse P2 when performing normal printing. That is, the driving frequency of the flushing drive pulse P1 is lower than the drive frequency of the recording drive pulse P2 (for example, 1 to 5 kHz). In addition, the speed of ink droplets ejected by bubble removal flushing is characterized by being slower than the speed of ink droplets ejected during normal printing. That is, the flushing drive pulse P1 is designed to be slower than the speed of the ink droplet ejected by the recording drive pulse P2. The drive voltage V1 of the flushing drive pulse P1 may be the same as the drive voltage V2 of the recording drive pulse P2, or may be different from V2 such as V1> V2.
Note that the driving voltage of the driving pulse of the flushing during recording performed during printing and the pre-printing flushing performed immediately before printing is set to be the same as the driving voltage V2 of the recording driving pulse P2, for example. In some cases, the driving pulse for flushing during recording or flushing before printing is made the same as the driving pulse P2 for recording. In order to repeatedly eject ink droplets from the nozzle 23 a predetermined number of times, a normal flushing drive pulse is supplied to the drive element 48 repeatedly a predetermined number of times. During normal flushing, for example, ink droplets are simultaneously ejected from all the nozzles 23 included in the nozzle row 43 in units of the nozzle row 43.

FIGS. 6A to 6C schematically illustrate the bubble removal mechanism by bubble removal flushing. FIG. 6A illustrates the state of the pressure chamber 44b before the continuous bubble removal flushing set is performed (before time t0 in FIG. 4B). The pressure chamber 44b is filled with ink FL1, and the bubble FL1 is mixed in the ink FL1. FIG. 6B illustrates the state of the pressure chamber 44b at times t0 to t2 in FIG. When the rising pulse portion Pwc is supplied, the driving element 48 contracts as the applied voltage increases. Then, the vibration plate 49 curves toward the outside of the pressure chamber 44b (the upper side in FIG. 6B), and a negative pressure is generated in the ink FL1 in the pressure chamber 44b. At this time, the degree of curvature of the meniscus ME1 generated in the nozzle 23 increases in the same direction as the diaphragm 49. As the pressure in the pressure chamber 44b decreases, the bubble AR1 increases. FIG. 6C illustrates the state of the pressure chamber 44b at times t2 to t3. Due to the falling pulse portion Pwd, the voltage applied to the driving element 48 returns to the base value, the driving element 48 expands to return to the ground state, and the diaphragm 49 returns to the flat state. The bubble AR1 gradually approaches the nozzle 23 as the ink FL1 is discharged, and is finally discharged from the nozzle 23 to the outside.
As described above, according to the continuous bubble removal flushing set, even a fine bubble can be removed.

(4) Explanation of nozzle inspection processing:
Next, an example of nozzle inspection processing performed by the controller 70 will be described with reference to FIG. This process is executed, for example, when a nozzle inspection is instructed. The nozzle inspection instruction includes a predetermined operation input for instructing a nozzle inspection from the user to the printer 20, a predetermined signal input for instructing a nozzle inspection from the host apparatus 10 to the printer 20, and the like. Further, when the power is turned on, when a print job is received from the host device 10, when printing of one page on the recording medium M1 is completed, when printing of a predetermined number of pages on the recording medium M1 is completed, the predetermined number of passes of the carriage main scan is reached. The nozzle inspection process may be executed at the end.

  When the nozzle inspection process is started, the controller 70 drives the carriage motor 34a to move the carriage 22 to the home position (Step S102; hereinafter, “Step” is omitted). As a result, the nozzle plate 27 of the print head 24 and the capping device 40 face each other. At this time, a predetermined gap (gap) GA1 (see FIG. 5) between the nozzle 23 and the electrode 52 is generated. In S <b> 104, the switch SW <b> 1 is switched to the on side to turn on the voltage application circuit 54, and the voltage of the high voltage power source Ve is applied to the electrode 52. In S106, a counter C indicating the number of executions of the maintenance process is provided in the RAM 74, and 1 is assigned to the counter C. In S108, a flushing + nozzle determination process described later is performed, and the determination result is stored in a memory such as the RAM 74.

  In S110, it is determined whether or not dot missing has been detected, that is, whether or not the state of the nozzles, preferably all the nozzles, is normal. For example, it may be determined whether or not the determination result stored in the memory such as the RAM 74 is information indicating that the determination result is normal. When dot missing is not detected, the controller 70 switches the switch SW1 to the off side to turn off the voltage application circuit 54 to disconnect from the electrode 52 (S120), and ends the nozzle inspection process.

  When the missing dot is detected, the controller 70 determines whether or not the counter C exceeds the counter threshold Cref (S112). The counter threshold value Cref is set as the upper limit of the number of times the maintenance process is repeated, and is set to, for example, twice. If C ≦ Cref, the controller 70 performs a maintenance process such as a cleaning process (S114). In the cleaning process, with the nozzle plate 27 sealed, the internal space formed by the print head 24 and the cap 41 is set to a negative pressure to forcibly suck ink in the nozzles 23. Thereby, the ink clogged in the nozzle 23 is removed by suction. In the maintenance process, a maintenance process that does not include a suction operation such as a wiping process may be performed. The wiping process is a process of wiping the nozzle surface 27a with a wiper provided beside the cap 41 or the like. After the maintenance process, the controller 70 adds 1 to the counter C (S116), and returns the process to S108.

  On the other hand, if C> Cref in S112, the state of the nozzle 23 does not become normal even though the maintenance process is repeated, so that the controller 70 does not eliminate the abnormal nozzle state on the display unit of the operation panel 79. Is displayed (S118). Thereafter, the controller 70 turns off the voltage application circuit 54 (S120) and ends the nozzle inspection process.

(5) First flushing + nozzle determination process:
FIG. 8 is a flowchart illustrating the first flushing + nozzle determination process performed in S108 of FIG. This processing is performed for all the nozzles 23 provided in the print head 24. For simplification, 180 nozzles (23K) of any one of the nozzle rows 43C, 43M, 43Y, and 43K (for example, the nozzle row 43K) are used. ). When the nozzle determination process is performed for each nozzle row 43, the processing shown in FIG. 8 may be performed for each of the nozzle rows 43C, 43M, 43Y, and 43K. Here, “above” is described as being higher than the threshold, and “below” is described as being lower than the threshold. Accordingly, the description of “above” includes “greater than”, and the description of “below” includes “less than”. These assumptions are the same in the following description unless otherwise noted.

  When the first flushing + nozzle determination process is started, the controller 70 controls the print head 24 to repeatedly supply the drive pulse 48 for bubble removal flushing to the drive element 48, and the ink FL2 from all the nozzles 23. A flushing process for discharging the liquid is executed (S130). For example, as shown in the sequence example of FIG. 10A, a flushing process is performed in which ink FL2 is simultaneously ejected from all 180 nozzles. Thus, even if there are unstable nozzles such as the nozzles 233 and 234 shown in the upper part of FIG. 1, the nozzles are restored to the normal state by the bubble removal flushing as shown in the middle part of FIG.

  After the flushing process, the controller 70 executes an inspection process by the nozzle inspection unit U1. First, the controller 70 provides the RAM 74 with a counter n indicating the set number of times of determination target nozzles, and substitutes 1 for the counter n (S132). In S134, the print head 24 is controlled so that a predetermined number of shots of the ink FL3 are ejected from the nth nozzle. That is, ink droplet ejection during the nozzle determination process is performed for each nozzle. The predetermined number of shots may be set according to the printer model, such as 8 to 24 shots. At this time, the voltage detection circuit 56 detects a voltage change ΔV1 caused by ink droplet ejection from the nth nozzle. The comparison circuit 57 compares the voltage change ΔV1 with the threshold value Vref, generates an H determination signal Vout when ΔV1 is higher than Vref, and outputs it to the controller 70. When ΔV1 is lower than Vref, the comparison circuit 57 outputs L. A determination signal Vout is generated and output to the controller 70.

The controller 70 reads the state of the determination signal Vout input to the input port (S136), and branches the process according to the state of the determination signal Vout (S138). If the state of the determination signal Vout is L (ΔV1 is equal to or lower than Vref), the controller 70 registers the nth nozzle in the memory such as the RAM 74 as an abnormal nozzle (S140). In S142, it is determined whether or not the counter n exceeds the counter threshold value Nref. The counter threshold Nref is set as the number of nozzles for determining the state, and is set to 180 when determining the states of all 180 nozzles. When n ≦ Nref, the controller 70 adds 1 to the counter n (S144), and returns the process to S134. On the other hand, if n> Nref, the controller 70 ends the flushing + nozzle determination process. In the example of FIG. 10A, it is shown that the nozzle determination process (inspection process) is performed in the order from the first nozzle to the 180th nozzle. Accordingly, when the time from the end of the flushing process at the nth nozzle to the start of the inspection process is represented by TIn, the time TIn of all 180 nozzles is different, and from the time TI1 of the first nozzle to the time TI180 of the 180th nozzle. The inspection time Tc of each nozzle becomes longer in order. The total time of the nozzle determination process varies depending on the printer model, for example, from the order of 100 milliseconds to about 1 second. The first nozzle time TI1 is shorter than the total time of the nozzle determination process, but the last The time TI 180 for 180 nozzles is longer than the total time for the nozzle determination process. The reason why the nozzle determination process for each nozzle cannot be performed in parallel is that there is only one electrode 52 for all nozzles, and when ink droplets are ejected from a plurality of nozzles, the ejection state of each nozzle is normal. This is because it cannot be determined.
As described above, it is determined whether or not each nozzle is in a normal state.

  Here, since the unstable nozzles such as the nozzles 233 and 234 in the upper stage of FIG. 1 are restored to the normal state by the flushing process of S130 before the inspection process, the number of unstable nozzles that are not maintained after the nozzle inspection is reduced. In addition, since a clogged nozzle such as the nozzle 231 in the upper stage of FIG. 1 may be restored to a normal state, maintenance processing such as cleaning is reduced overall, and ink consumption is reduced. Of course, if a clogged nozzle remains after the flushing process like the nozzle 232 in the middle of FIG. 1, a maintenance process such as cleaning is performed, and the nozzle is restored to a normal state.

  The nozzle inspection process described above is applied to various scenes such as initial filling of ink from the ink cartridge, every predetermined period of non-printing, reception of operation input of manual cleaning processing, and continuation of printing processing. Can do.

FIG. 9 is a flowchart illustrating an example of executing the nozzle inspection process described above during the printing process. When the controller 70 receives the print data together with the print execution command from the host device 10 (S202), the controller 70 drives the printer mechanism 21 and the paper feed mechanism 31 according to the print data to execute the printing process (S204).
The controller 70 suspends the printing process after a predetermined time has elapsed from the start of printing, and executes the nozzle inspection process described above (S206). In this nozzle inspection process, the print head 24 is moved to the home position, and the bubble removal flushing drive pulse (P1) is repeatedly supplied to the drive element 48 to perform the flushing process, followed by executing the inspection process. + Nozzle inspection process ”. In S208, it is determined whether dot missing has been detected. If no missing dot is detected, the controller 70 returns the process to S204 and continues to execute the printing process. On the other hand, if a missing dot is detected, a maintenance process such as cleaning is performed in S114 of FIG. 7, and the controller 70 returns the process to S206 and executes the “bubble removal flushing + nozzle inspection process” again.

  When the “bubble removal flushing + nozzle inspection process” of S206 is first performed, the inspection process by the nozzle inspection unit U1 is performed after the flushing process is performed. That is, the flushing process is performed immediately before the inspection process is performed by first ejecting the ink FL3 from the nozzle 23.

  FIG. 14 is a flowchart showing processing at the time of printing according to the comparative example. When receiving the print data together with the print execution command from the host device 10 (S902), the controller of this comparative example drives the printer mechanism and the paper feed mechanism according to the print data and executes the printing process (S904). The controller suspends the printing process after a predetermined time has elapsed from the start of printing, and executes the “no-flushing nozzle inspection process” without the flushing process (S906). This “no-flushing nozzle inspection process” can be, for example, the processes of S102 to S104 in FIG. 7 and S132 to S144 in FIG. In S908, it is determined whether a missing dot is detected. If no missing dot is detected, the controller returns the process to S904 and continues the printing process. On the other hand, when dot missing is detected, bubble removal flushing is performed for the first time (S910), the process returns to S906, and the nozzle inspection process is executed again.

  In the case of the comparative example, when the nozzle inspection process of S906 is first performed, if there are unstable nozzles such as the nozzles 233 and 234 shown in the upper part of FIG. 1, the unstable nozzles are in a normal state. May be judged. In this case, the unstable nozzles are used for printing, and the dots of ink droplets ejected from the unstable nozzles may deteriorate the print image quality.

In the embodiment shown in FIG. 9, since the flushing process is performed immediately before the nozzle inspection, the unstable nozzle is restored to the normal state. Therefore, in the nozzle inspection after the flushing process, as illustrated in the lower part of FIG. 1, the nozzle that was in an unstable state is actually changed to a normal state even if it is determined to be in a normal state. Unstable nozzles are reduced. Note that the time from the end of the flushing process to the start of the inspection process is the same in the case of the first inspection process after print data is acquired and in the case of the inspection process executed again.
As described above, the present technology has an aspect in which the flushing process is executed from the beginning immediately before the inspection process. In addition, the present technology always performs a flushing process and an inspection process as a series of operations as a side surface for executing the flushing process before the inspection process, a side surface for performing the flushing process as part of the nozzle inspection process, and a nozzle inspection process. A side surface, a side surface for executing the flushing process a predetermined time before the inspection process is executed, and the like.

  As described above, this mode can reduce the number of unstable nozzles used for printing without maintenance after nozzle inspection because the nozzles in an unstable state can be brought into a normal state by the flushing process. Thus, it is possible to suppress a decrease in print image quality.

(6) Second flushing + nozzle determination process:
In the first flushing + nozzle determination process described above, as shown in FIG. 10A, the time TIn from the end of the flushing process to the start of the inspection process differs for each nozzle. However, in order to reduce the influence on the ejection state due to the difference in ink thickening after the completion of the flushing process, the time TIn is equalized as illustrated in FIGS. 10B to 10D. preferable.

  FIG. 10B shows a sequence example in which the time TIn is made equal to TI0 for each of the nozzles 23 when only one electrode 52 is provided in the nozzle inspection unit U1. In this case, when the ink FL2 is ejected for flushing a certain nozzle, this ejection is detected by the voltage detection circuit 56 as a voltage change. Therefore, if the ink FL3 is ejected for nozzle inspection for another nozzle at the same time, it cannot be determined whether or not the other nozzle is in a normal state due to a voltage change due to the ejection of the ink FL2. Therefore, the nozzle determination process (inspection process) of the first first nozzle is started after the ink FL2 is ejected from all 180 nozzles.

  The second flushing + nozzle determination process can be performed according to the flow of FIG. 8 only by changing the flushing process of S130 shown in FIG. That is, in S130, the start of ink ejection is sequentially delayed from the first nozzle to the 180th nozzle by the inspection time Tc, and the ink ejection is sequentially performed by the inspection time Tc from the first nozzle to the 180th nozzle in the nozzle determination process. It is good to delay the start. Thereby, the time TIn from the end of the flushing process to the execution of the inspection process is made equal to each nozzle. Therefore, this aspect can provide a suitable configuration that reduces the number of unstable nozzles 23 that are not maintained after nozzle inspection.

(7) Third flushing + nozzle determination process:
If the electrode 52 is provided for each nozzle and the flushing process and the inspection process can be performed in parallel by increasing the number of electrodes 52, the time TIn from the end of the flushing process to the start of the inspection process is shortened. Can do.

  FIG. 10C shows a sequence example in which the time TIn is equalized for each of the nozzles 23 when the electrode 52 is provided for each nozzle. For example, the nozzle determination process (inspection process) for the first nozzle and the flushing process for the fourth nozzle are executed in parallel. In this case, the first nozzle corresponds to the first nozzle according to the present invention, and the fourth nozzle corresponds to the second nozzle according to the present invention. Thus, when the inspection process for a certain nozzle and the flushing process for another nozzle are executed in parallel, the nozzle inspection can be performed quickly.

  Further, even if the electrode 52 is not provided for each nozzle, if a plurality of electrodes 52 are provided in the nozzle inspection unit U1, a certain nozzle is separately subjected to the flushing process using the first electrode. The nozzle can be inspected using the second electrode.

  FIG. 11 shows a modification in which the cap 41 is divided in units of 43 nozzle rows (nozzle groups). The cap 41 includes divided caps 41C, 41M, 41Y, and 41K that face the nozzle rows 43C, 43M, 43Y, and 43K, respectively. Accordingly, the nozzle rows 43C, 43M, 43Y, and 43K are set as execution units for maintenance such as cleaning.

  Electrodes 52C, 52M, 52Y, and 52K are provided inside the division caps 41C, 41M, 41Y, and 41K, respectively. The nozzle inspection unit U1 is provided with a switch SW2 interposed between the electrodes 52C, 52M, 52Y, 52K and the voltage detection circuit 56. The switch SW2 selects one of electrodes 52C, 52M, 52Y, and 52K to be connected to the voltage detection circuit 56 in accordance with an instruction from the controller 70. For example, when the switch SW2 is switched to the electrode 52K, a voltage change ΔV1 due to ink droplets ejected from the nozzles 23K of the nozzle row 43K is detected, and ink droplets are ejected from the nozzles 23C, 23M, and 23Y of the nozzle rows 43C, 43M, and 43Y. Even if it is ejected, it is not detected as a voltage change. Accordingly, the inspection process can be performed on the nozzles 23K of the nozzle array 43K while performing the flushing process on at least some of the nozzles 23C, 23M, and 23Y of the nozzle arrays 43C, 43M, and 43Y. In this case, the nozzle row 43K corresponds to the first nozzle group referred to in the present invention, the nozzle 23K corresponds to the first nozzle included in the first nozzle group, and the nozzle rows 43C, 43M, and 43Y correspond to the present invention. The nozzles 23C, 23M, and 23Y correspond to a second nozzle group that corresponds to the second nozzle group.

FIG. 12 shows a third flushing + nozzle that executes in parallel the inspection process for the first nozzle included in the first nozzle group and the flushing process for the second nozzle included in the second nozzle group. The determination process is shown by a flowchart. This process is performed for all nozzle rows 43C, 43M, 43Y, and 43K.
When the third flushing + nozzle determination process is started, the controller 70 provides a counter n indicating the set number of determination target nozzles in the RAM 74, and substitutes 1 for the counter n (S302). In S304, a control for repeatedly supplying the driving pulse (P1) for bubble removal flushing to the driving element 48 of the Kth nth nozzle is performed, and a flushing process for ejecting the ink FL2 from the Kth nth nozzle is executed. In S306, after the inspection time Tc from the start of the flushing process of the Kth nth nozzle, the same driving pulse is supplied, and the flushing process of ejecting the ink FL2 from the Cth nozzle is executed. In S308, after the inspection time Tc from the start of the flushing process of the C-th nth nozzle, the same driving pulse is supplied to execute the flushing process of ejecting the ink FL2 from the Mth nozzle. In S310, after the inspection time Tc from the start of the flushing process of the Mth nth nozzle, the same drive pulse is supplied to perform the flushing process of ejecting the ink FL2 from the Ynth nozzle.

In step S312, the process waits until the flushing process for the K-th nozzle is completed. In S314, after the time TI0 from the end of the flushing process to the start of the inspection process, an inspection process for discharging a predetermined number of shots of ink FL3 from the Kth nozzle is executed. In S316, if the state of the determination signal Vout is L (ΔV1 is equal to or lower than Vref), the K-th nozzle is registered as an abnormal nozzle. In S318, after the inspection time Tc from the start of the inspection process for the Kth nth nozzle, the inspection process for ejecting a predetermined number of shots of ink FL3 from the Cth nth nozzle is executed. In S320, if the state of the determination signal Vout is L, the C-th nozzle is registered as an abnormal nozzle. In S322, after the inspection time Tc from the start of the inspection process for the C nth nozzle, the inspection process for ejecting a predetermined number of shots of ink FL3 from the Mth nozzle is executed. In S324, if the state of the determination signal Vout is L, the Mth nozzle is registered as an abnormal nozzle. In S326, after the inspection time Tc from the start of the inspection process for the Mth nth nozzle, the inspection process for ejecting a predetermined number of shots of ink FL3 from the Yth nth nozzle is executed. In S328, if the state of the determination signal Vout is L, the Yth nth nozzle is registered as an abnormal nozzle.
The controller 70 executes the processes of S304 to S328 Nref times (S330 to S332), and ends the third flushing + nozzle determination process.

By the above processing, for example, the inspection processing for the nozzle 23K and the flushing processing for the nozzles 23C, 23M, and 23Y can be executed in parallel, and the inspection processing for the nozzle 23C and the flushing processing for the nozzles 23M, 23Y can be performed. Can be executed in parallel, and the inspection process for the nozzle 23M and the flushing process for the nozzle 23Y can be executed in parallel. Therefore, according to this aspect, the nozzle inspection can be quickly performed.
Of course, if the voltage detection circuit 56 is also provided for each nozzle row, the flushing + nozzle determination process can be performed independently for each nozzle row.

(8) Fourth flushing + nozzle determination process:
FIG. 10D shows a sequence example in which the time TI0 from the end of the flushing process to the start of the inspection process is shortened when only one electrode 52 is provided in the nozzle inspection unit U1. For example, after the “flushing + nozzle determination process” is completed for the first nozzle, the “flushing + nozzle determination process” is executed for the second nozzle. In this case, the first nozzle corresponds to the first nozzle according to the present invention, and the second nozzle corresponds to the second nozzle according to the present invention.

FIG. 13 is a flowchart showing a fourth flushing + nozzle determination process for shortening the time TI0. In this process, S130 is deleted from the process shown in FIG. 8, and S150 is added.
When the fourth flushing + nozzle determination process is started, the controller 70 provides a counter n indicating the set number of determination target nozzles in the RAM 74, and substitutes 1 for the counter n (S132). Next, a control for repeatedly supplying the driving pulse (P1) for bubble removal flushing to the driving element 48 of the nth nozzle is performed, and a flushing process for discharging the ink FL2 from the nth nozzle is executed (S150). Thereafter, the print head 24 is controlled so that a predetermined number of shots of the ink FL3 are ejected from the nth nozzle (S134), and if the determination signal Vout is L, the nth nozzle is registered as an abnormal nozzle ( S136-S140). The controller 70 executes the processes of S150 and S134 to S140 Nref times (S142 to S144), and ends the fourth flushing + nozzle determination process.

  With the above processing, after a series of processes of the flushing process and the inspection process for the first nozzle is completed, a series of processes of the flushing process and the inspection process is performed for the second nozzle. Therefore, this aspect can provide a suitable configuration that reduces the number of unstable nozzles that are not maintained after nozzle inspection.

(9) Modification:
The embodiment described above can also be changed to the following form.
The nozzle inspection may be performed in a region other than the home position, and the electrode 52 may be provided in this region.
The electrical change detection means for detecting the electrical change may be configured by a circuit or the like that detects a current change caused by the fluid discharged from the nozzle 23.

The processing described above may be performed by an external device connected to the printer, such as the host device 10. In this case, a nozzle inspection device is provided in the external device, and a fluid ejection device is provided across the printer and the external device. Of course, the above-described processing may be performed in cooperation between the printer and the external device. In this case, a nozzle inspection device and a fluid ejection device are provided across the printer and the external device. That is, the fluid ejection device of the present invention may be configured by a system including a printer and an external device.
The order of the steps of the above-described processing can be changed as appropriate. For example, in the nozzle inspection process of FIG. 7, the counter C addition process in S116 may be performed before the maintenance process in S114.

In the above-described embodiment, the alternative detection of whether or not the nozzle is in a normal state is performed. However, whether the nozzle is in a normal state, a clogged state, or an unstable state is detected. The above state may be detected.
Even when a controller capable of reading the value of the voltage change ΔV1 detected by the voltage detection circuit 56 is used, it is possible to determine whether or not the state of the nozzle 23 is normal by performing the above-described processing. That is, this aspect has a good versatility that it can be implemented regardless of whether or not the controller can read the value of the voltage change.

  In addition to color ink jet printers, printing devices include monochromatic machines, dot impact printers, laser printers, multifunction printers equipped with scanning means such as scanners and colorimeters, and print heads that are formed long in the width direction of the recording medium. On the other hand, a line printer that conveys a recording medium and performs printing may be used. In addition to paper, the recording medium may be a resin sheet, a metal film, a cloth, a film substrate, a resin substrate, a semiconductor wafer, a storage medium such as an optical disk or a magnetic disk, and the like. The shape of the recording medium may be a long shape, a three-dimensional shape, etc. in addition to a cut sheet.

The fluid ejection apparatus to which the present invention can be applied may be an apparatus that ejects fluid other than ink, such as a liquid ejection apparatus including a liquid ejection head that ejects (discharges) a minute amount of liquid droplets in addition to a printer. The term “droplet” as used herein refers to the state of the liquid ejected from the liquid ejecting apparatus, and includes a granular shape, a tear shape, a thread-like shape, and the like. The liquid here may be any material that can be discharged by the liquid discharge device. For example, as a liquid in a state when the substance is in a liquid phase, a liquid material having a high or low viscosity, sol, gel water Inorganic solvents, organic solvents, solutions, liquid resins, fluids such as liquid metals (metal melts), and the like are included. Further, not only a liquid as one state of a substance but also a substance in which particles of a functional material made of a solid such as a pigment or a metal particle are dissolved, dispersed or mixed in a solvent are included. Ink, liquid crystal, and the like are typical examples of liquids. The ink includes general water-based ink and oil-based ink, and various liquid compositions such as gel ink and hot melt ink. Examples of the liquid ejection device include a device for ejecting a liquid containing a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, or a color filter in a dispersed or dissolved state. Is included. In addition, the liquid ejection device is a device that ejects biological organic materials used in biochip manufacturing, a device that ejects liquid as a sample used as a precision pipette, a textile printing device, a microdispenser, a clock or a camera. In order to etch a substrate, a device for discharging a transparent resin liquid such as an ultraviolet curable resin to form a device for discharging lubricating oil, a micro hemispherical lens (optical lens) used for an optical communication element, etc. An apparatus for discharging an etching solution such as acid or alkali is included.
The fluid is preferably a non-gaseous fluid, but may be a granular material such as toner.

An aspect in which the inspection process is performed after the flushing process is performed on one nozzle is also included in the present invention.
Of course, the above-described basic actions and effects can be obtained even with an apparatus, a system, a method, a program, or the like that does not have the configuration requirements according to the dependent claims but only the configuration requirements according to the independent claims.

As described above, according to the present invention, according to various aspects, it is possible to provide a technique for reducing the number of unstable nozzles that are not maintained after nozzle inspection.
In addition, it is also possible to implement the present invention by mutually replacing the configurations disclosed in the above-described embodiments and modifications, and changing the combination. It is also possible to carry out the present invention by substituting each component disclosed in the above or changing the combination. Therefore, the present invention is not limited to the above-described embodiments and modifications, and includes configurations in which the configurations disclosed in the publicly known technology and the above-described embodiments and modifications are mutually replaced or combinations thereof are changed. It is.

DESCRIPTION OF SYMBOLS 10 ... Host device, 20 ... Printer, 21 ... Printer mechanism, 22 ... Carriage, 23, 23C, 23M, 23Y, 23K ... Nozzle, 24 ... Print head (discharge head), 24t ... Temperature detection part, 27 ... Nozzle plate, 27a ... Nozzle surface, 40 ... Capping device, 41 ... Cap, 41C, 41M, 41Y, 41K ... Split cap, 43, 43C, 43M, 43Y, 43K ... Nozzle array (nozzle group), 48 ... Drive element, 50 ... Nozzle Inspection device 52, 52C, 52M, 52Y, 52K ... electrode, 54 ... voltage application circuit, 56 ... voltage detection circuit, 57 ... comparison circuit, 60 ... original signal generation circuit, 70 ... controller, 80 ... mechanical frame, 90 ... Lifting device, AR1 ... bubble, FL1, FL2, FL3 ... ink (fluid), M1 ... recording medium, ME1 ... meniscus P1 ... Flushing drive pulse, P2 ... Recording drive pulse, T1 ... Flushing drive pulse cycle, T2 ... Recording drive pulse cycle, TIn ... Time from the end of the flushing process to the start of the inspection process, Tc: inspection time, U1: nozzle inspection unit, U2: control unit.

Claims (8)

An ejection head capable of ejecting fluid from a nozzle;
A nozzle inspection unit for inspecting the discharge state of the fluid from the nozzle;
When performing the inspection process by the nozzle inspection unit by discharging the fluid from the nozzle, a control unit that performs the inspection process after performing the flushing process of discharging the fluid for flushing from the nozzle;
A fluid ejection device comprising: The control unit executes the flushing process and the inspection process again when a missing dot is detected by the inspection process,
The time from the end of the flushing process to the start of the inspection process is equal between the case of the first inspection process after print data is acquired and the case of the inspection process executed again. Item 2. The fluid ejection device according to Item 1. The ejection head has a plurality of the nozzles,
3. The fluid ejection device according to claim 1, wherein the time from the end of the flushing process to the start of the inspection process is equalized for each of the nozzles. The nozzle includes at least a first nozzle and a second nozzle;
The fluid according to any one of claims 1 to 3, wherein the control unit executes the inspection process for the first nozzle and the flushing process for the second nozzle in parallel. Discharge device. The discharge head includes at least a first and a second nozzle group which are set as a maintenance execution unit,
The control unit executes the inspection process for the first nozzle included in the first nozzle group and the flushing process for the second nozzle included in the second nozzle group in parallel. The fluid ejection device according to claim 4. The nozzle includes at least a first nozzle and a second nozzle;
The control unit performs the inspection process after performing the flushing process for the second nozzle after performing the inspection process after performing the flushing process for the first nozzle. Item 4. The fluid ejection device according to any one of Items 3 to 3. A nozzle inspection method for discharging a fluid from a nozzle provided in a discharge head and inspecting a discharge state of the fluid from the nozzle,
A nozzle inspection method for performing an inspection process after performing a flushing process for ejecting a fluid for flushing from the nozzle when performing an inspection process by discharging a fluid from the nozzle. A nozzle inspection program for discharging a fluid from a nozzle provided in a discharge head and inspecting a discharge state of the fluid from the nozzle,
A nozzle inspection program for causing a computer to realize a function of executing an inspection process after performing a flushing process for discharging a fluid from the nozzle for flushing when the fluid is discharged from the nozzle.

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