JP2020179511A - Liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily estimate a liquid viscosity in a plurality of nozzles of a liquid discharge head.
SOLUTION: A plurality of nozzles of an inkjet head and a detection conductive portion arranged in a cap are opposed to each other (S101), and ink is ejected or flushed from the nozzles to generate viscosity estimation data. (S103). The viscosity estimation data is data on the relationship between the amplitude of the differential signal obtained by differentiating the detection signal output from the detection conductive portion and the viscosity of the ink in the nozzle. After generating the viscosity estimation data, the viscosity of the ink in the nozzle is estimated (S104). At this time, ink is ejected from the nozzle while maintaining the positional relationship between the inkjet head and the cap, and the viscosity of the ink in the nozzle is estimated based on the amplitude of the differential signal at this time and the viscosity estimation data. Do.
[Selection diagram] FIG. 7

Description

The present invention relates to a liquid discharge device that discharges a liquid from a nozzle.

As an example of a liquid ejection device that ejects a liquid from a nozzle, Patent Document 1 describes an inkjet recording apparatus that ejects ink droplets from a nozzle to perform recording. In the inkjet recording apparatus of Patent Document 1, pressure is applied to the ink in the pressure generating chamber to eject ink droplets from the nozzle. Then, the viscosity of the ink is calculated based on the information corresponding to the residual pressure wave generated in the pressure generation chamber after the ink droplets are ejected.

Japanese Patent No. 6287387

Here, in Patent Document 1, it is necessary to acquire information corresponding to the residual pressure wave in order to estimate the change in the viscosity of the ink, but various processes are required for the acquisition. Therefore, the processing required to obtain the viscosity of the ink becomes complicated.

An object of the present invention is to provide a liquid discharge device capable of easily estimating the viscosity of a liquid in a liquid discharge head.

The liquid discharge device of the present invention has a liquid discharge head having a nozzle and a conductive portion for detection, and is a signal of an electrical change generated in the conductive portion for detection by the liquid discharged from the nozzle. The control unit includes a signal output unit and a control unit that output a detection signal which is a signal whose electrical change is different depending on the discharge characteristics of the liquid from the nozzle, and the control unit includes the detection signal and the inside of the nozzle. Inside the nozzle based on the viscosity estimation data regarding the relationship with the viscosity of the liquid and the detection signal output from the signal output unit when the liquid is discharged from the nozzle by controlling the liquid discharge head. Estimate the viscosity of the liquid in.

In the present invention, the viscosity estimation data regarding the relationship between the signal output from the signal output unit and the viscosity of the liquid in the nozzle and the signal output from the signal output unit when the liquid is discharged from the nozzle are used. , The viscosity of the liquid in the nozzle can be easily estimated.

It is a schematic block diagram of the printer which concerns on embodiment of this invention. It is a top view of the inkjet head of FIG. FIG. 2 is a sectional view taken along line III-III of FIG. It is a figure for demonstrating the detection conductive part arranged in the cap, and the connection relationship between the detection conductive part, a high voltage power supply circuit, and a determination circuit. (A) is a diagram showing a detection signal output from the detection conductive portion when ink is ejected from the nozzle, and (b) is a diagram showing when the detection signal shown in (a) is output from the detection conductive portion. It is a figure which shows the differential signal output from a differentiating circuit. It is a block diagram which shows the electrical structure of a printer. It is a flowchart which shows the flow of the process at the time of estimating the viscosity of the ink in a nozzle. It is a flowchart which shows the flow of the viscosity estimation data generation processing of FIG. (A) is a diagram showing the relationship between the viscosity before ejection and the amount of ink ejected to reduce the viscosity to the minimum, and (b) is the relationship between the viscosity of the ink in the nozzle and the amplitude of the differential signal. It is a figure which shows. It is a flowchart which shows the flow of the process at the time of generating the viscosity estimation data in the modification 1. It is a flowchart which shows the flow of the viscosity estimation data generation processing of the modification 2. (A) is a diagram corresponding to FIG. 4 of the modified example 3, and (b) associates the driving potential and the viscosity of the ink of the modified example 3 with the value of the signal indicating whether or not the ink is ejected from the nozzle. It is a figure for demonstrating the table. It is a flowchart which shows the flow of the process at the time of estimating the viscosity of the ink in a nozzle in the modification 3.

Hereinafter, preferred embodiments of the present invention will be described.

<Overall printer configuration>
As shown in FIG. 1, the printer 1 (“liquid discharge device” of the present invention) according to the present embodiment includes a carriage 2, a sub tank 3, an inkjet head 4 (“liquid discharge head” of the present invention), a platen 5, and a transfer. It is equipped with rollers 6 and 7, a maintenance unit 8, and the like.

The carriage 2 is supported by two guide rails 11 and 12 extending in the scanning direction. The carriage 2 is connected to a carriage motor 86 (see FIG. 6) via a belt or the like (not shown), and when the carriage motor 86 is driven, the carriage 2 moves in the scanning direction along the guide rails 11 and 12. In the following, as shown in FIG. 1, the right side and the left side in the scanning direction are defined and described.

The sub tank 3 is mounted on the carriage 2. Here, the printer 1 is provided with a cartridge holder 14, and four ink cartridges 15 are detachably mounted on the cartridge holder 14. Black, yellow, cyan, and magenta inks (the "liquid" of the present invention) are stored in the four ink cartridges 15 from those arranged on the right side in the scanning direction. The sub tank 3 is connected to four ink cartridges 15 mounted on the cartridge holder 14 via four tubes 13. As a result, the four color inks are supplied from the four ink cartridges 15 to the sub tank 3.

The inkjet head 4 is mounted on the carriage 2 and is connected to the lower end of the sub tank 3. The above four colors of ink are supplied from the sub tank 3 to the inkjet head 4. Further, the inkjet head 4 ejects ink from a plurality of nozzles 10 formed on the nozzle surface 4a which is the lower surface thereof. More specifically, the plurality of nozzles 10 form a nozzle row 9 by arranging them in a transport direction orthogonal to the scanning direction, and the inkjet head 4 has four rows of nozzle rows 9 arranged in the scanning direction. Has. Black, yellow, cyan, and magenta inks are ejected from the plurality of nozzles 10 from those forming the nozzle row 9 on the right side in the scanning direction. In the present embodiment, the nozzle 10 for ejecting black ink (the "first liquid" of the present invention) constituting the rightmost nozzle row 9 corresponds to the "first nozzle" of the present invention, and the leftmost three rows. The nozzle 10 for ejecting color ink (yellow, cyan, magenta ink, "second liquid" of the present invention) constituting the nozzle row 9 of the present invention corresponds to the "second nozzle" of the present invention.

The platen 5 is arranged below the inkjet head 4 and faces the plurality of nozzles 10. The platen 5 extends in the scanning direction over the entire length of the recording paper P (“the medium to be ejected” of the present invention) and supports the recording paper P from below. The transfer roller 6 is arranged on the upstream side in the transfer direction with respect to the inkjet head 4 and the platen 5. The transfer roller 7 is arranged on the downstream side in the transfer direction with respect to the inkjet head 4 and the platen 5. The transfer rollers 6 and 7 are connected to the transfer motor 87 (see FIG. 6) via a gear (not shown) or the like. When the transfer motor 87 is driven, the transfer rollers 6 and 7 rotate, and the recording paper P is conveyed in the transfer direction.

The maintenance unit 8 is for performing suction purging as described later to eject the ink in the inkjet head 4 from the plurality of nozzles 10. The maintenance unit 8 will be described in detail later.

<Inkjet head>
Next, the inkjet head 4 will be described in detail. As shown in FIGS. 2 and 3, the inkjet head 4 includes a flow path unit 21 and a piezoelectric actuator 22.

<Flower flow unit>
The flow path unit 21 is formed by stacking four plates 31 to 34 in this order from the top. The plates 31 to 33 are made of a metal material such as stainless steel. The plate 34 is made of a synthetic resin material such as polyimide.

A plurality of nozzles 10 are formed on the plate 34. The plurality of nozzles 10 form four rows of nozzle rows 9 as described above. The lower surface of the plate 34 is the nozzle surface 4a of the inkjet head 4. A plurality of pressure chambers 40 are formed in the plate 31. The pressure chamber 40 has an elliptical planar shape with the scanning direction as the longitudinal direction. Further, the plurality of pressure chambers 40 are individual to the plurality of nozzles 10, and the left end portion in the scanning direction overlaps the nozzles 10 in the vertical direction. As a result, the plate 31 is formed by arranging a plurality of pressure chambers 40 in the transport direction, respectively, and four rows of pressure chamber rows 29 arranged in the scanning direction are formed.

The plate 32 is formed with a circular through hole 42 at a portion that overlaps the right end portion of each pressure chamber 40 in the scanning direction in the vertical direction. Further, the plate 32 is formed with a circular through hole 43 at the left end portion of each pressure chamber 40 in the scanning direction and a portion overlapping the nozzle 10 in the vertical direction.

Four manifold flow paths 41 are formed on the plate 33. The four manifold flow paths 41 correspond to the four pressure chamber rows 29. The manifold flow path 41 extends in the transport direction and overlaps the portion on the right side in the scanning direction of the plurality of pressure chambers 40 constituting the corresponding pressure chamber rows 29 in the vertical direction. As a result, each pressure chamber 40 communicates with the manifold flow path 41 through the through hole 42. Further, a supply port 39 is provided at the upstream end of each manifold flow path 41 in the transport direction. The inkjet head 4 is connected to the flow path in the sub tank 3 at the supply port 39. As a result, ink is supplied to the manifold flow path 41 from the supply port 39. Further, in the plate 33, a circular through hole 44 is formed in a portion overlapping each through hole 43 and the nozzle 10 in the vertical direction. As a result, each nozzle 10 communicates with the pressure chamber 40 through the through holes 43 and 44.

In the flow path unit 21, an individual flow path 46 is formed by one nozzle 10, a pressure chamber 40 corresponding to the nozzle 10, and through holes 42 to 44.

<Piezoelectric actuator>
The piezoelectric actuator 22 includes a diaphragm 51, a piezoelectric layer 52, a common electrode 53, and a plurality of individual electrodes 54. The diaphragm 51 is made of a piezoelectric material containing lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate, as a main component, is arranged on the upper surface of the flow path unit 21, and covers a plurality of pressure chambers 40. ing. The diaphragm 51 may be made of an insulating material other than the piezoelectric material, unlike the piezoelectric layer 52 described below.

The piezoelectric layer 52 is made of the above-mentioned piezoelectric material, is arranged on the upper surface of the diaphragm 51, and extends continuously over a plurality of pressure chambers 40. The common electrode 53 is arranged between the diaphragm 51 and the piezoelectric layer 52, and extends continuously across the plurality of pressure chambers 40. The common electrode 53 is connected to a power supply circuit (not shown) via a wiring member (not shown) or the like, and is held at the ground potential.

The plurality of individual electrodes 54 are individual to the plurality of pressure chambers 40. The individual electrode 54 has an elliptical planar shape that is one size smaller than the pressure chamber 40, is arranged on the upper surface of the piezoelectric layer 52, and overlaps the central portion of the pressure chamber 40 in the vertical direction. Further, the right end portion of the individual electrode 54 in the scanning direction extends to the right side in the scanning direction to a position where it does not overlap with the pressure chamber 40 in the vertical direction, and the tip end portion thereof serves as a connection terminal 54a. A wiring member (not shown) is connected to the connection terminal 54a, and the individual electrode 54 is connected to the driver IC 59 (see FIG. 6) via the wiring member. Then, the driver IC 59 selectively imparts either a ground potential or a predetermined drive potential (for example, about 20 V) to the plurality of individual electrodes 54.

Further, corresponding to the arrangement of the common electrode 53 and the plurality of individual electrodes 54 in this manner, the portions sandwiched between the common electrode 53 of the piezoelectric layer 52 and the individual electrodes 54 are respectively arranged in the thickness direction. It is polarized. In the piezoelectric actuator 22 having the above structure, the portion of the diaphragm 51, the piezoelectric layer 52, and the common electrode 53 that overlaps each pressure chamber 40 in the vertical direction and the portion formed by the individual electrodes 54 are respectively. , The drive element 50 applies pressure to the ink in the pressure chamber 40.

Here, in each drive element 50 of the piezoelectric actuator 22, when the potential of the individual electrode 54 is switched from the ground potential to the drive potential, the potential difference between the individual electrode 54 and the common electrode 53 causes these electrodes of the piezoelectric layer 52. An electric potential in the thickness direction parallel to the polarization direction is generated in the portion sandwiched between the two. Due to this electric field, the portion of the piezoelectric layer 52 contracts in the horizontal direction, and the portion of the diaphragm 51 and the piezoelectric layer 52 that overlaps the pressure chamber 40 in the vertical direction is deformed so as to be convex toward the pressure chamber 40 as a whole. Further, when the potential of the individual electrode 54 is switched from the drive potential to the ground potential, the individual electrode 54 and the common electrode 53 become the same potential, and the portion of the diaphragm 51 and the piezoelectric layer 52 that overlaps the pressure chamber 40 in the vertical direction It returns to the state before the above transformation. Then, when the potential of the individual electrode 54 is switched between the ground potential and the drive potential, the volume inside the pressure chamber 40 is increased due to the deformation of the portion of the vibrating plate 51 and the piezoelectric layer 52 that overlaps the pressure chamber 40 in the vertical direction. The pressure is applied to the ink in the pressure chamber 40 by changing, and the ink is ejected from the nozzle 10 communicating with the pressure chamber 40.

<Maintenance unit>
Next, the maintenance unit 8 will be described. As shown in FIG. 1, the maintenance unit 8 includes a cap 61, a suction pump 62, and a waste liquid tank 63. The cap 61 is arranged on the right side in the scanning direction with respect to the platen 5. Then, when the carriage 2 is positioned at the maintenance position on the right side of the platen 5 in the scanning direction, the plurality of nozzles 10 face the cap 61.

Further, the cap 61 can be raised and lowered by the cap raising and lowering mechanism 88 (see FIG. 6). In the present embodiment, the carriage 2 on which the inkjet head 4 is mounted and moves in the scanning direction and the cap elevating mechanism 88 for elevating and lowering the cap 61 on which the detection conductive portion 66 described later is arranged are combined. It corresponds to the "relative moving means" of the present invention.

Then, when the cap 61 is raised by the cap elevating mechanism 88 with the carriage 2 positioned at the maintenance position and the plurality of nozzles 10 and the cap 61 facing each other, the upper end portion of the cap 61 comes into close contact with the nozzle surface 4a. Then, the plurality of nozzles 10 are covered with the cap 61. The cap 61 is not limited to covering the plurality of nozzles 10 by being in close contact with the nozzle surface 4a. The cap 61 may cover a plurality of nozzles 10 by, for example, being brought into close contact with a frame (not shown) arranged around the nozzle surface 4a of the inkjet head 4.

The suction pump 62 is a tube pump or the like, and is connected to the cap 61 and the waste liquid tank 63. Then, in the maintenance unit 8, when the suction pump 62 is driven with the plurality of nozzles 10 covered by the cap 61 as described above, the ink in the inkjet head 4 is discharged from the plurality of nozzles 10, so-called suction purge. (The "discharge operation" of the present invention) can be performed. The ink discharged from the inkjet head 4 is stored in the waste liquid tank 63. In the present embodiment, the maintenance unit 8 that performs suction purging corresponds to the "purging means" of the present invention.

Here, for convenience, the cap 61 covers all the nozzles 10 together, and in the suction purge, the ink in the inkjet head 4 is discharged from all the nozzles 10, but this is limited to this. Absent. For example, the cap 61 covers a plurality of nozzles 10 constituting the rightmost nozzle row 9 for ejecting black ink, and the left three rows of nozzle rows 9 for ejecting color ink (yellow, cyan, magenta ink). Even if a portion that covers a plurality of nozzles 10 constituting the above is separately provided, and either black ink or color ink in the inkjet head 4 can be selectively discharged in the suction purge. Good.

Further, as shown in FIG. 4, a detection conductive portion 66 having a rectangular planar shape is arranged in the cap 61. The detection conductive portion 66 is connected to the high voltage power supply circuit 67 via a resistor 69. Then, a predetermined negative potential (for example, about −300 V) is applied to the detection conductive portion 66 by the high voltage power supply circuit 67. On the other hand, the flow path unit 21 of the inkjet head 4 is held at the ground potential. As a result, a potential difference is generated between the inkjet head 4 and the detection conductive portion 66. In the present embodiment, the combination of the detection conductive portion 66, the high voltage power supply circuit 67 connected thereto, and the resistor 69 corresponds to the "signal output portion" of the present invention.

When ink is ejected from the nozzle 10 toward the detection conductive portion 66 while the carriage 2 is located at the maintenance position, a detection signal as shown in FIG. 5A is emitted from the detection conductive portion 66. It is output. Here, FIG. 5A shows a change in the potential of the detection conductive portion 66 when ink is continuously ejected from the nozzle 10.

The change in the potential of the detection conductive portion 66 when the ink is ejected from the nozzle 10 toward the detection conductive portion 66 will be described in more detail. As described above, the detection conductive portion 66 and the inkjet head 4 The ink discharged from the nozzle 10 is charged due to the potential difference of. Then, when the charged ink is ejected from the nozzle 10, as shown in FIG. 5A, the detection conductive portion is between the time when the ink starts to be ejected and the time when the ink lands on the detection conductive portion 66. The potential of 66 drops. After that, while the ink is continuously ejected from the nozzle 10, the state in which the potential of the detection conductive portion 66 is lowered is maintained. Although not shown, when the ink ejection from the nozzle 10 is stopped, the potential of the detection conductive portion 66 gradually rises and returns to the potential before the ink ejection.

Here, when ink is ejected from the nozzle 10, the higher the viscosity of the ink in the nozzle 10, the slower the flying speed of the ink and the smaller the volume of the ejected ink. Then, as the flying speed of the ink ejected from the nozzle 10 is slower, the potential of the detection conductive portion 66 changes more slowly. That is, as shown by the broken line in FIG. 5A, the slope of the change in the potential of the detection conductive portion 66 becomes small. Further, the smaller the volume of the ink ejected from the nozzle 10, the smaller the amount of change in the potential of the detection conductive portion 66. That is, as shown by the alternate long and short dash line in FIG. 5A, the amount of change in potential becomes small. At this time, as shown by the alternate long and short dash line in FIG. 5A, the slope of the change in the potential of the detection conductive portion 66 also becomes small. From these facts, the slope of the change in potential in the detection signal of FIG. 5A corresponds to the viscosity of the ink in the nozzle 10. In the present embodiment, the flying speed of the ink and the volume of the ejected ink correspond to the "ejection characteristics" of the present invention. Then, in the present embodiment, the slope of the change in the potential of the detection conductive portion 66 (“how to change the detection signal” of the present invention) differs depending on the ejection characteristics (the flying speed of the ink and the volume of the ejected ink). ..

A differentiating circuit 68 is connected to the detection conductive portion 66. The differentiating circuit 68 outputs a differentiating signal obtained by second-order differentiation of the detection signal output from the detection conductive unit 66 as shown in FIG. 5 (b). The maximum amplitude H of the differential signal, which is the difference between the minimum value when the value of the differential signal is first maximized and the maximum value when the value of the differential signal is first maximized (hereinafter, simply differentiated). The signal amplitude H) corresponds to the slope of the change in potential in the detection signal of FIG. 5A. As described above, since the slope of the change in potential in the detection signal of FIG. 5A corresponds to the viscosity of the ink in the nozzle 10, the amplitude H of the differential signal of FIG. 5B corresponds to the nozzle 10. Corresponds to the viscosity of the ink inside.

Here, the differentiating circuit 68 may be one that differentiates the detected signal to the first order. However, when the differentiating circuit 68 differentiates the detection signal in the second order as in the present embodiment, the amplitude H in the differentiating signal can be made larger than in the case where the detection signal is differentiated in the first order. Further, the differentiating circuit 68 may be one that differentiates the detected signal to the third order or higher. Further, the differentiating circuit 68 is a circuit formed by using an analog filter such as a high-pass filter and a low-pass filter. Therefore, the differential signal output from the differentiating circuit 68 is slightly different from the signal obtained by mathematically differentiating the detection signal output from the detection conductive unit 66 to the second order.

Here, the high-voltage power supply circuit 67 applies a negative potential to the detection conductive portion 66, but the high-voltage power supply circuit 67 gives the detection conductive portion 66 a positive potential (for example, about 300 V). It may be granted. In this case, the change in potential in the detection signal and the differential signal when the ink is ejected from the nozzle 10 toward the detection conductive portion 66 with the carriage 2 positioned at the maintenance position is described above. It is the opposite of.

<Electrical configuration of printer>
Next, the electrical configuration of the printer 1 will be described. The operation of the printer 1 is controlled by the control device 80. As shown in FIG. 6, the control device 80 is composed of a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 82, a RAM (Random Access Memory) 83, a flash memory 84, an ASIC (Application Specific Integrated Circuit) 85, and the like. The operation of the carriage motor 86, the transfer motor 87, the cap elevating mechanism 88, the high voltage power supply circuit 67, the suction pump 62, and the like is controlled. Further, the control device 80 controls the inkjet head 4 by controlling the driver IC 59. Further, the above-mentioned signal is input to the control device 80 from the determination circuit 68.

In the control device 80, only the CPU 81 may perform various processes, only the ASIC 85 may perform various processes, or the CPU 81 and the ASIC 85 cooperate with each other to perform various processes. It may be a thing. Further, the control device 80 may be one in which one CPU 81 performs processing independently, or one in which a plurality of CPUs 81 share the processing. Further, in the control device 80, one ASIC 85 may perform the processing independently, or a plurality of ASIC 85s may share the processing.

<Control during recording, etc.>
Then, in the printer 1, the control device 80 causes the recording paper P to record an image by alternately performing the recording path and the conveying operation. The recording path means that the control device 80 drives the carriage motor 86 to move the carriage 2 in the scanning direction and controls the inkjet head 4, thereby injecting ink from the plurality of nozzles 10 toward the recording paper P. This is the operation of discharging. The transport operation is an operation of driving the transport motor 87 to transport the recording paper P to the transport rollers 6 and 7 by a predetermined distance.

Further, in the printer 1, the control device 80 controls the inkjet head 4 immediately before the first recording pass when recording an image on the recording paper P, and ink in the inkjet head 4 is discharged from the plurality of nozzles 10. Flushing to discharge is performed.

Further, in the printer 1, the control device 80 controls the carriage motor 86, the cap elevating mechanism 88, the suction pump 62, and the like, for example, every time a predetermined time elapses without recording on the recording paper P. Periodically perform the above-mentioned suction purge.

<Estimation of ink viscosity in nozzle>
Next, in the printer 1, the estimation of the viscosity of the ink in the plurality of nozzles 10 of the inkjet head 4 will be described. When estimating the viscosity of the ink in the plurality of nozzles 10 of the inkjet head 4, the control device 80 performs the process according to the flow of FIG. 7. In this embodiment, for example, the viscosities of the inks in the plurality of nozzles 10 of the inkjet head 4 are estimated periodically, for example.

Explaining the flow processing of FIG. 7 in more detail, first, the control device 80 controls the carriage motor 86 and the cap elevating mechanism 88, and the inkjet head 4 and the detection conductive portion 66 are combined with the plurality of nozzles 10. The detection conductive portions 66 arranged in the cap 61 face each other, and these have a predetermined positional relationship separated by a predetermined distance.

However, during the period from the previous estimation of the viscosity of the ink in the nozzle 10 to the estimation of the viscosity of the ink in the nozzle 10 this time, the inkjet head 4 and the detection conductive portion 66 are maintained in the above-mentioned predetermined positional relationship. In this case, in S101, the cap elevating mechanism 88 is not driven, and the inkjet head 4 and the detection conductive portion 66 are maintained in the predetermined positional relationship.

Subsequently, the control device 80 moves relative to the inkjet head 4 and the detection conductive portion 66 during the period from the previous estimation of the ink viscosity in the nozzle 10 to the estimation of the viscosity of the ink in the nozzle 10 this time. Is determined (S102). Specifically, it is determined whether or not the carriage 2 has been moved in the scanning direction and the cap 61 has been raised or lowered during the above period. If the relative movement is not performed (S102: NO), the process proceeds to S104 as it is. On the other hand, when the relative movement is performed (S102: YES), the control device 80 executes the viscosity estimation data generation process of S103, and then proceeds to S104.

In the viscosity estimation data generation process of S103, the control device 80 performs the process according to the flow of FIG. More specifically, the control device 80 first controls the inkjet head 4 to form a representative black nozzle, which is one of a plurality of nozzles 10 for ejecting black ink, which constitutes the rightmost nozzle row 9. Ink is ejected toward the detection conductive portion 66 (S201). The representative black nozzle is, for example, the nozzle 10 on the most downstream side in the transport direction among the plurality of nozzles 10 constituting the rightmost nozzle row 9. The nozzle 10 is the farthest from the supply port 39 among the plurality of nozzles forming the rightmost nozzle row 9, and it is highly possible that the ink has the highest viscosity.

Then, the control device 80 acquires the amplitude H1k of the differential signal output from the differentiating circuit 68 when the black ink is ejected from the representative black nozzle in S201 (S202).

Subsequently, the control device 80 controls the inkjet head 4 and conducts detection from a representative color nozzle, which is one of a plurality of nozzles 10 for ejecting color ink, which constitutes the nozzle row 9 in the left three rows. Ink is ejected toward the portion 66 (S203). The representative color nozzle is, for example, the nozzle 10 on the most downstream side in the transport direction among the plurality of nozzles 10 constituting any of the nozzle rows 9 in the left three rows. The nozzle 10 is the farthest from the supply port 39 among the plurality of nozzles 10 constituting the nozzle row 9 in the left three rows, and it is highly possible that the ink has the highest viscosity.

Then, the control device 80 acquires the amplitude H1c of the differential signal output from the differentiating circuit 68 when the color ink is ejected from the representative color nozzle in S203 (S204).

In the present embodiment, the combination of the operation of ejecting black ink from the representative black nozzle in S201 and the operation of ejecting color ink from the representative color nozzle in S203 is the "first ejection operation" of the present invention. Equivalent to.

Subsequently, the control device 80 controls the inkjet head 4 to flush the representative black nozzle, which discharges the black ink in the inkjet head 4 from the representative black nozzle (S205). Next, the control device 80 discharges black ink from the representative black nozzle toward the detection conductive portion 66, and at this time, is the amplitude H of the differential signal output from the differentiating circuit 68 changed by a predetermined amount or more? It is determined whether or not (S206). More specifically, in S206 after the first flushing of S205, it is determined whether or not the amplitude H of the differential signal changes by a predetermined amount or more with respect to the amplitude H1k acquired in S202. Further, as will be described later, in S206 after the second and subsequent flushing of S205 when the flushing of S205 is repeatedly performed, the amplitude H of the differential signal is from the amplitude H of the differential signal immediately after the previous flushing of S205. It is determined whether or not the change is more than a predetermined amount.

Then, while the amplitude H of the differential signal changes by a predetermined amount or more (S206: YES), flushing of the representative black nozzle is repeated (S205). Here, as described above, the amplitude H of the differential signal corresponds to the viscosity of the ink in the nozzle 10. Therefore, in the present embodiment, the representative black nozzle is flushed until the viscosity of the ink in the representative black nozzle is reduced to the minimum viscosity W2k (“predetermined viscosity” of the present invention) for the black ink and does not change any more. It will be repeated. The minimum viscosity W2k is a viscosity determined by conditions such as the type of ink, temperature, and humidity.

When the amount of change in the amplitude H of the differential signal becomes less than a predetermined amount (S206: NO), the control device 80 subsequently controls the inkjet head 4 to obtain color ink in the inkjet head 4 from the representative color nozzle. Is flushed with a representative color nozzle (S207). Next, the control device 80 discharges the color ink from the representative color nozzle toward the detection conductive portion 66, and at this time, whether the amplitude H of the differential signal output from the differentiating circuit 68 changes by a predetermined amount or more. It is determined whether or not (S208). More specifically, in S208 after the first flushing of S207, it is determined whether or not the amplitude H of the differential signal changes by a predetermined amount or more with respect to the amplitude H1c acquired in S204. Further, as will be described later, in S208 after the second and subsequent flushing of S207 when the flushing of S207 is repeatedly performed, the amplitude H of the differential signal is from the amplitude H of the differential signal immediately after the previous flushing of S207. It is determined whether or not the change is more than a predetermined amount.

Then, while the amplitude H of the differential signal changes by a predetermined amount or more (S208: YES), flushing of the representative color nozzle is repeated (S207). As a result, as described above, until the viscosity of the ink in the representative color nozzle is reduced to the minimum viscosity W2c (“predetermined viscosity” of the present invention) for the color ink and does not change any more, the representative color nozzle Flushing will be repeated. The minimum viscosity W2c is a viscosity determined by conditions such as the type of ink, temperature, and humidity.

When the amount of change in the amplitude H of the differential signal becomes less than a predetermined amount (S208: NO), the controller 80 determines the pre-discharge viscosity W1k, which is the viscosity of the black ink in the representative black nozzle immediately before the first flushing of S205. , And the pre-discharge viscosity W1c, which is the viscosity of the color ink in the representative color nozzle immediately before the first flushing of S207, is acquired (S209).

More specifically, the pre-discharge viscosity, which is the viscosity of the ink in the nozzle 10 before discharging the ink, and the total amount of ink discharged in order to reduce the viscosity of the ink in the nozzle 10 to the minimum viscosity. Is proportional. Then, in the flash memory 84, for example, as shown in FIG. 9A, a straight line L1k showing the relationship between the pre-discharge viscosity of the black ink and the total discharge amount, and the color ink before discharge. The data of the straight line L1c showing the relationship between the viscosity and the total emission amount is stored. In the present embodiment, the data of the straight lines L1k and L1c correspond to the "emission amount data" of the present invention. Further, the data of the straight lines L1k and L1c are data that have been acquired in advance by an experiment or the like and stored in the flash memory 84.

Then, in S209, the total amount of black ink discharged F1k calculated by the number of times the flushing of the representative black nozzle of S205 is repeated and the amount of ink discharged in one flushing of the representative black nozzle, and the straight line L1k. Based on the data, the pre-discharge viscosity W1k is obtained. Further, the ink is discharged from the total ink discharge amount F1c calculated by the number of times the flushing of the representative color nozzle of S207 is repeated and the ink discharge amount in one flushing of the representative color nozzle, and the data of the straight line L1c. Obtain the pre-viscosity W1c.

Subsequently, the control device 80 controls the inkjet head 4 to eject black ink from the representative black nozzle toward the detection conductive portion 66 (S210), and obtains the amplitude H2k of the differential signal output from the differentiating circuit 68. Acquire (S211). Subsequently, the control device 80 controls the inkjet head 4 to eject color ink from the representative color nozzle toward the detection conductive portion 66 (S212), and adjusts the amplitude H2c of the differential signal output from the differentiating circuit 68. Acquire (S213).

Subsequently, the control device 80 generates viscosity estimation data (S214), and returns to the flow of FIG. 7. Here, the viscosity of the ink in the nozzle 10 and the amplitude H of the differential signal are in a proportional relationship. In S214, the amplitude H1k of the differential signal acquired in S202 and the viscosity W1k before discharge (information at the point T1k in FIG. 9B) acquired in S209, and the amplitude H2k and the minimum viscosity W2k of the differential signal acquired in S211 (FIG. 9). Based on the information of the point T2k of 9 (b)), the data of the straight line L2k showing the relationship between the viscosity of the black ink in the nozzle 10 and the amplitude H of the differential signal as shown in FIG. 9 (b) is obtained. Generate. At this time, the higher the pre-discharge viscosity W1k of the representative black nozzle, the greater the distance between the points T1k and T2k in FIG. 9B, and the data of the straight line L2k generated based on the information of the points T1k and T2k is the ink. The relationship between the viscosity of and the amplitude H of the differential signal can be expressed more accurately.

Further, in S214, the amplitude H1c of the differential signal acquired in S204 and the pre-discharge viscosity W1c (information at the point T1c in FIG. 9B) acquired in S209, the amplitude H2c of the differential signal acquired in S213, and the minimum viscosity are described above. A straight line L2c showing the relationship between the viscosity of the color ink in the nozzle 10 and the amplitude H of the differential signal as shown in FIG. 9B based on W2c (information at the point T2c in FIG. 9B). Generate the data of. At this time, the higher the pre-discharge viscosity W1c of the representative color nozzle, the larger the distance between the points T1c and T2c in FIG. 9B, and the data of the straight line L2c generated based on the information of the points T1c and T2c is the ink. The relationship between the viscosity of and the amplitude H of the differential signal can be expressed more accurately.

In the present embodiment, the data of the straight lines L2k and L2c correspond to the "viscosity estimation data" of the present invention. Further, the data of the straight line L2k corresponds to the "data for estimating the first viscosity" of the present invention, and the data of the straight line L2c corresponds to the "data for estimating the second viscosity" of the present invention.

Returning to FIG. 7, in S104, the control device 80 estimates the viscosity of the ink in the nozzle 10 for each of the plurality of nozzles 10 of the inkjet head 4. More specifically, in S104, the control device 80 controls the inkjet head 4 to eject ink from one nozzle 10 that ejects black ink among the plurality of nozzles 10, and at this time, the differentiating circuit 68 The viscosity of the black ink in the nozzle 10 is estimated based on the amplitude H of the differentiating signal output from the nozzle 10 and the data of the straight line L2k. Further, in S104, the control device 80 controls the inkjet head 4 to eject ink from one nozzle 10 that ejects color ink among the plurality of nozzles 10, and at this time, the ink is output from the differentiating circuit 68. The viscosity of the color ink in the nozzle 10 is estimated based on the amplitude H of the differentiating signal and the data of the straight line L2c.

Further, in S104, the viscosity of the ink in the nozzles 10 is estimated for each of the plurality of nozzles 10 of the inkjet head 4 as described above. However, when the viscosity estimation data generation process of S103 is executed immediately before S104, it is estimated that the viscosity of the ink in the representative black nozzle is the minimum viscosity W2k, and the viscosity of the ink in the representative color nozzle is estimated. It is estimated that the viscosity is the minimum viscosity W2c, and the viscosity of the ink in the nozzle 10 is estimated for each of the nozzles 10 other than the representative black nozzle and the representative color nozzle as described above.

Subsequently, the control device 80 makes a setting at the time of recording based on the viscosity of the ink in the nozzle 10 estimated in S104 (S105). In S105, for example, when ejecting ink from each nozzle 10, the waveform of the drive signal output from the driver IC 59 to each drive element 50 is set according to the estimated viscosity of the ink. Alternatively, for example, the higher the average value of the viscosities of the inks for the estimated plurality of nozzles 10, the higher the drive potential applied to the drive element 50 from the driver IC 59. As a result, in the printer 1, when ink is ejected from the plurality of nozzles 10 of the inkjet head 4 toward the recording paper P and an image is recorded on the recording paper P, the inkjet head is based on the estimated viscosity of the ink. 4 is controlled.

Subsequently, the control device 80 sets the purge based on the viscosity of the ink in the nozzle 10 estimated in S104 (S106). In S106, for example, the higher the average value of the estimated ink viscosities, the higher the frequency of periodic suction purging, and the larger the amount of ink discharged from the inkjet head 4 in the suction purging (driving the suction pump 62). (For example, lengthening the time). As a result, suction purging is performed based on the estimated viscosity of the ink.

Subsequently, the control device 80 sets the flushing based on the viscosity of the ink in the nozzle 10 estimated in S104 (S107). In S107, for example, the higher the average value of the estimated ink viscosities, the more the amount of ink discharged during flushing (the number of times ink is discharged from the nozzle 10). As a result, flushing is performed based on the estimated viscosity of the ink.

<Effect>
In the present embodiment, as described above, the slope of the voltage change of the detection signal output from the detection conductive unit 66 when the ink is ejected from the nozzle 10 and the differentiation of the detection signal by the differentiating circuit 68. The signal amplitude H corresponds to the viscosity of the ink in the nozzle 10. Therefore, in the present embodiment, the linear L2k data showing the relationship between the amplitude H of the differential signal and the viscosity of the black ink in the nozzle 10 and the differential output from the differentiating circuit 68 when the black ink is ejected from the nozzle 10 The viscosity of the black ink in the nozzle 10 is estimated based on the signal amplitude H. Further, the linear L2c data showing the relationship between the amplitude H of the differential signal and the viscosity of the color ink in the nozzle 10 and the amplitude H of the differential signal output from the differentiating circuit 68 when the color ink is ejected from the nozzle 10 The viscosity of the color ink in the nozzle 10 is estimated based on. Thereby, the viscosity of the ink in the nozzle 10 can be easily estimated.

Further, in the present embodiment, the data of the straight line L1k stored in advance and the total amount of black ink discharged F1k by flushing the representative black nozzle until the viscosity of the black ink in the representative black nozzle drops to the minimum viscosity W2k. Based on this, the pre-discharge viscosity W1k is obtained. Then, based on the amplitude H1k of the differential signal before flushing of the representative black nozzle, the viscosity W1k before discharge, the amplitude H2k of the differential signal after flushing of the representative black nozzle, and the minimum viscosity W2k, the viscosity estimation data is used. Data of a certain straight line L2k can be generated.

Similarly, in the present embodiment, the data of the straight line L1c stored in advance and the total discharge amount F1c of the color ink by flushing the representative color nozzle until the viscosity of the color ink in the representative color nozzle drops to the minimum viscosity W2c. The pre-discharge viscosity W1c is obtained based on. Then, based on the amplitude H1c of the differential signal before flushing of the representative color nozzle, the viscosity W1c before discharge, the amplitude H2c of the differential signal after flushing of the representative color nozzle, and the minimum viscosity W2c, the viscosity estimation data is used. Data of a certain straight line L2c can be generated.

Further, the relationship between the detection signal and the differential signal and the viscosity of the ink in the nozzle 10 is substantially the same for each of the plurality of nozzles 10 for ejecting the black ink of the inkjet head 4. Further, the relationship between the detection signal and the differential signal and the viscosity of the ink in the nozzle 10 is substantially the same for each of the plurality of nozzles 10 for ejecting the color ink of the inkjet head 4. Therefore, as described above, for the nozzle 10 that generates viscosity estimation data for the representative black nozzle and ejects black ink other than the representative black nozzle, the viscosity of the ink is estimated using the viscosity estimation data for the representative black nozzle. can do. Similarly, for the nozzle 10 that generates viscosity estimation data for the representative color nozzle and ejects color ink other than the representative color nozzle, the viscosity of the ink can be estimated using the viscosity estimation data for the representative color nozzle. ..

Further, the relationship between the detection signal and the differential signal obtained by differentiating the detected signal and the viscosity of the ink in the nozzle 10 differs depending on the type of ink, for example, the straight line L2k and the straight line L2c become different straight lines. Therefore, in the present embodiment, the data of the straight line L2k and the data of the straight line L2c are separately generated as the viscosity estimation data. Then, the viscosity of the ink in the nozzle 10 for ejecting the black ink is estimated based on the data of the straight line L2k and the amplitude H of the differential signal when the black ink is ejected from the nozzle 10. Further, the viscosity of the ink in the nozzle 10 for ejecting the color ink is estimated based on the data of the straight line L2c and the amplitude H of the differential signal when the color ink is ejected from the nozzle 10. Thereby, the viscosity of the ink in the nozzle 10 can be accurately estimated for each of the nozzles 10 for ejecting the black ink and the color ink.

Further, in the present embodiment, there is some play between the carriage 2 and the guide rails 11 and 12. Therefore, when the carriage 2 is moved to the maintenance position, the carriage 2 may be slightly tilted. At this time, the nozzle surface 4a of the inkjet head 4 mounted on the carriage 2 also tilts. Further, when the cap 61 is raised by the cap elevating mechanism 88, the cap 61 also has some rattling so that the cap 61 follows the inclination of the nozzle surface 4a and comes into close contact with the nozzle surface 4a. It is attached to have. Therefore, the distance between the nozzle surface 4a and the detection conductive portion 66 varies every time the inkjet head 4 and the detection conductive portion 66 are in the predetermined positional relationship due to the movement of the carriage 2 and the raising and lowering of the cap 61.

When the distance between the nozzle 10 and the detection conductive portion 66 changes, the detection signal output from the detection conductive portion 66 when ink is ejected from the nozzle 10 toward the detection conductive portion 66 changes, and accordingly. Therefore, the differential signal output from the differentiating circuit 68 also changes. From this, there is a difference (for example, 100 μm or more) between the distance between the nozzle 10 and the detection conductive portion 66 when the viscosity estimation data (L2k, L2c data) is generated and when the ink viscosity is estimated. If there is a difference), the viscosity of the ink estimated based on the viscosity estimation data may deviate significantly from the actual viscosity.

On the other hand, in the present embodiment, as described above, immediately before estimating the viscosity of the ink in the nozzle 10, the inkjet head 4 and the detection conductive portion 66 have the above-mentioned predetermined positional relationship, and the viscosity estimation data. To generate. After that, while maintaining the positional relationship between the inkjet head 4 and the detection conductive portion 66, the nozzle is based on the amplitude H of the differential signal when the ink is ejected from the nozzle 10 and the generated viscosity estimation data. The viscosity of the ink in 10 is estimated. As a result, the distance between the nozzle 10 and the detection conductive portion 66 can be made the same when generating the viscosity estimation data and when estimating the viscosity of the ink in the nozzle 10. As a result, the estimated viscosity of the ink in the nozzle 10 becomes accurate.

Further, in the present embodiment, the carriage 2 is not moved and the cap 61 is not moved up and down during the period from the previous estimation of the ink viscosity in the nozzle 10 to the estimation of the ink viscosity in the nozzle 10 this time. In the case of (the relative movement between the inkjet head 4 and the detection conductive portion 66 is not performed), the time when the ink viscosity in the nozzle 10 is estimated last time and the time when the ink viscosity in the nozzle 10 is estimated this time. Therefore, the distance between the nozzle 10 and the detection conductive portion 66 is the same. Therefore, in such a case, the viscosity of the ink in the nozzle 10 this time is estimated by using the viscosity estimation data generated immediately before estimating the viscosity of the ink in the nozzle 10 last time. As a result, it is not necessary to generate the viscosity estimation data immediately before the estimation of the viscosity of the ink in the nozzle 10 this time, and the time required for estimating the viscosity of the ink in the nozzle 10 can be shortened.

Then, in the present embodiment, when ink is ejected from the nozzle 10 toward the recording paper P to perform recording, the inkjet head 4 is controlled based on the estimated viscosity of the ink in the nozzle 10. As a result, the ink can be appropriately ejected from the nozzle 10 toward the recording paper P according to the viscosity of the ink in the nozzle 10.

Further, in the present embodiment, suction purging can be appropriately performed according to the estimated viscosity of the ink in the nozzle 10.

Further, in the present embodiment, flushing can be appropriately performed according to the estimated viscosity of the ink in the nozzle 10.

<Modification example>
Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made as long as it is described in the claims.

In the above-described embodiment, the information of the two points T1k and T2k was acquired, and the data of the straight line L2k was generated based on the information. Further, the information of the two points T1c and T2c was acquired, and the data of the straight line L2c was generated based on the information. However, it is not limited to this.

For example, information on three or more points on the plane of FIG. 9B may be acquired, and data of a straight line L2k may be generated based on the information. Similarly, information on three or more points on the plane of FIG. 9B may be acquired, and data on the straight line L2c may be generated based on the information. Further, in these cases, instead of the straight lines L2k and L2c, curve data such as a quadratic function or a cubic function showing the relationship between the viscosity of the ink and the amplitude of the differential signal based on the information of the above three points or more ( The "data for estimating viscosity") of the present invention may be generated.

Further, in the above-described embodiment, the representative black nozzle generates linear L2k data as viscosity estimation data (first viscosity estimation data) by ejecting ink or flushing the representative black nozzle as described above. For the nozzles that eject black ink other than the above, the viscosity of the ink in the nozzle 10 is estimated using the data of the straight line L2k. Further, by ejecting and flushing the representative color nozzle as described above, the data of the straight line L2c is generated as the viscosity estimation data (second viscosity estimation data), and the color ink other than the representative color nozzle is ejected. The viscosity of the ink in the nozzle 10 is estimated using the data of the straight line L2c for the nozzle to be used. However, it is not limited to this.

For example, if the relationship between the detection signal and the differential signal obtained by differentiating the detection signal and the viscosity of the ink in the nozzle 10 is significantly different among the four color inks of black, yellow, cyan, and magenta, each ink color is used. For the nozzle 10 that individually generates the viscosity estimation data and ejects the ink of each color, the viscosity of the ink in the nozzle 10 may be estimated by using the viscosity estimation data of the corresponding color. In this case, of the two different color inks, the nozzle 10 that ejects the ink of one color corresponds to the "first nozzle" of the present invention, and the nozzle 10 that ejects the ink of the other color is the present. Corresponds to the "second nozzle" of the invention. Further, the viscosity estimation data corresponding to the ink of one color corresponds to the "first viscosity estimation data" of the present invention, and the viscosity estimation data corresponding to the ink of the other color corresponds to the "first viscosity estimation data" of the present invention. Corresponds to "second viscosity estimation data".

Alternatively, if there is not a large difference in the relationship between the detection signal and the differential signal obtained by differentiating the detection signal and the viscosity of the ink in the nozzle 10 between the colors of the ink, any of the plurality of nozzles 10 of the inkjet head 4 Using the nozzle 10 as a representative nozzle, viscosity estimation data may be generated in the same manner as described above. Then, for the nozzle 10 that ejects ink of any color, the viscosity of the ink in the nozzle 10 may be estimated by using the viscosity estimation data.

Further, in the above-described embodiment, the carriage 2 is moved and the cap 61 is raised and lowered during the period from the previous estimation of the viscosity of the ink in the nozzle 10 to the estimation of the viscosity of the ink in the nozzle 10 this time. If not, the viscosity of the ink in the nozzle 10 this time was estimated using the viscosity estimation data generated immediately before estimating the viscosity of the ink in the nozzle 10 last time, but this is not limited to this. .. For example, regardless of whether the carriage 2 is moved and the cap 61 is raised or lowered during the period from the previous estimation of the viscosity of the ink in the nozzle 10 to the estimation of the viscosity of the ink in the nozzle 10 this time. The viscosity estimation data may be generated immediately before the estimation of the viscosity of the ink in the nozzle 10.

Further, in the above-described embodiment, the detection conductive portion 66 is arranged in the cap 61, and the viscosity estimation data is generated and the ink in the nozzle 10 is generated as the positional relationship between the inkjet head 4 and the cap 61 facing each other. The viscosity was estimated, but it is not limited to this.

For example, the detection conductive portion may be arranged outside the cap 61. Further, in this case, the positional relationship between the inkjet head 4 and the cap 61 when generating the viscosity estimation data and estimating the viscosity of the ink in the nozzle 10 is the positional relationship in which they face each other. Not limited to that. For example, assuming that the detection conductive portion extends in the vertical direction, a positional relationship in which the space facing the detection conductive portion in the horizontal direction and the inkjet head 4 overlap in the vertical direction (“predetermined positional relationship” of the present invention). ), The ink for ejection of ink from the nozzle 10 may be ejected, flushed, or the like to generate data for estimating the viscosity and estimate the viscosity of the ink in the nozzle 10.

Further, in the above-described embodiment, immediately before estimating the viscosity of the ink in the nozzle 10, the inkjet head 4 and the detection conductive portion 66 are in a predetermined positional relationship to generate viscosity estimation data. After that, while maintaining the positional relationship between the inkjet head 4 and the detection conductive portion 66, ink is ejected from the nozzle 10 to estimate the viscosity of the ink in the nozzle 10. However, it is not limited to this.

For example, when the variation in the distance between the nozzle 10 and the detection conductive portion 66 when the inkjet head 4 and the detection conductive portion 66 are in the above-mentioned predetermined positional relationship can be sufficiently reduced (for example, when the distance can be made less than 100 μm). ), The carriage 2 may be moved or the cap 61 may be moved up and down during the period from the generation of the viscosity estimation data to the estimation of the viscosity of the ink in the nozzle 10.

Further, in this case, the timing of generating the viscosity estimation data does not have to be immediately before estimating the viscosity of the ink in the nozzle 10. For example, the viscosity estimation data may be generated at the time of manufacturing the printer 1 or at the start of the first use of the printer 1.

Further, also in this case, the viscosity estimation data may be generated for the representative black nozzle and the representative color nozzle as in the above-described embodiment. Further, in this case, with respect to the nozzle 10 for ejecting black ink including the representative black nozzle, the viscosity in the nozzle 10 may be estimated by using the viscosity estimation data for the representative black nozzle. Further, for the nozzle 10 that ejects the color ink including the representative color nozzle, the viscosity in the nozzle 10 may be estimated by using the viscosity estimation data for the representative color nozzle.

Further, when the viscosity estimation data is generated at a timing different from that immediately before estimating the viscosity of the ink in the nozzle 10, the viscosity estimation data for the representative nozzle is not limited to the generation.

For example, in the first modification, the control device 80 generates viscosity estimation data by performing processing according to the flow shown in FIG. More specifically, the control device 80 first controls the inkjet head 4 to the detection conductive portion 66 in order from each of the plurality of nozzles 10 for ejecting black ink, which form the rightmost nozzle row 9. Ink is ejected toward (S301). Then, the control device 80 acquires the amplitude H1k of the differential signal output from the differentiating circuit 68 when the ink is ejected from each nozzle 10, and calculates the average value of these amplitudes H1k (S302).

Subsequently, the control device 80 controls the inkjet head 4 from each of the plurality of nozzles 10 for ejecting color ink, which constitute the nozzle rows 9 in the left three rows, toward the detection conductive portion 66 in order. Is discharged (S303). Then, the control device 80 acquires the amplitude H1c of the differential signal output from the differentiating circuit 68 when the ink is ejected from each nozzle 10, and calculates the average value of these amplitudes H1c (S304).

In the first modification, the present invention is a combination of the operation of ejecting black ink from the nozzle 10 for ejecting black ink in S301 and the operation of ejecting color ink from the nozzle 10 for ejecting color ink in S303. Corresponds to the "first discharge operation" of.

Subsequently, the control device 80 controls a plurality of drive elements 50 of the inkjet head 4 to flush the black nozzles by ejecting the black ink in the inkjet head 4 from the nozzles 10 that eject the black ink (S305). ).

Next, the control device 80 determines whether or not the average value of the amplitude H of the differential signals for the plurality of nozzles 10 for ejecting black ink has changed by a predetermined amount or more in the same manner as in S206 of the above-described embodiment. Judgment (S306). Then, while the average value of the amplitude H of the differential signal changes by a predetermined amount or more (S306: YES), the flushing of the black nozzle is repeated (S305).

When the amount of change in the average value of the amplitude H of the differential signal becomes less than a predetermined amount (S306: NO), the control device 80 subsequently controls the plurality of drive elements 50 of the inkjet head 4 to apply color ink. Flushing of the color nozzle is performed so that the color ink in the inkjet head 4 is discharged from the ejection nozzle 10 (S307). Next, the control device 80 determines whether or not the average value of the amplitude H of the differential signals for the plurality of nozzles 10 for ejecting the color ink has changed by a predetermined amount or more in the same manner as in S208 of the above-described embodiment. Judgment (S308). Then, while the average value of the amplitude H of the differential signal changes by a predetermined amount or more (S308: YES), the flushing of the color nozzle is repeated (S307). In the first modification, the driving element 50 for flushing the black nozzle and the color nozzle corresponds to the "discharge means" of the present invention.

When the amount of change in the average value of the amplitude H of the differential signal becomes less than a predetermined amount (S308: NO), the control device 80 determines the viscosity of the black ink in the nozzle 10 that ejects the black ink immediately before the first flushing of S305. The average value of the pre-discharge viscosity W1k and the average value of the pre-discharge viscosity W1c, which is the viscosity of the color ink in the nozzle 10 for ejecting the color ink immediately before the first flushing of S307, are acquired (S309).

In S309, as in the above embodiment, the total amount of black ink discharged F1k and the straight line L1k calculated by the number of times the flushing of S305 is repeated and the amount of ink discharged in one flushing of S305. The pre-discharge viscosity W1k is obtained from the information. Further, the pre-discharge viscosity W1c is obtained from the total discharge amount F1c of the color ink and the information of the straight line L1c calculated by the number of times the flushing of S307 is repeated and the amount of ink discharged in one flushing of S307. get.

However, in the case of the modified example 1, unlike the case of the above-described embodiment, the total discharge amount F1k in FIG. 9A is the total amount of ink discharged from all the nozzles 10 that discharge the black ink. Yes, the pre-discharge viscosity W1k is an average value of the pre-discharge viscosities of the plurality of nozzles 10 for ejecting black ink. Further, the total discharge amount F1c in FIG. 9A is the total amount of ink discharged from all the nozzles 10 for ejecting color ink, and the pre-discharge viscosity W1c is for a plurality of nozzles 10 for ejecting color ink. It is the average value of the viscosity before discharge.

Subsequently, the control device 80 ejects ink in order from a plurality of nozzles 10 for ejecting black ink (S310) as in S301, and a differentiating circuit when ink is ejected from each nozzle 10 as in S302. The amplitudes H2k of the differentiating signals output from 68 are acquired, and the average value of these amplitudes H2k is calculated (S311). Subsequently, the control device 80 ejects ink in order from a plurality of nozzles 10 for ejecting color ink (S312) as in S303, and a differentiating circuit when ink is ejected from each nozzle 10 as in S304. The amplitudes H2c of the differentiating signals output from 68 are acquired, and the average value of these amplitudes H2c is calculated (S313).

Subsequently, the control device 80 generates viscosity estimation data (S314). In S314, based on the average value of the amplitude H1k of the differential signal acquired in S302, the average value of the pre-discharge viscosity W1k acquired in S309, the average value of the amplitude H1c of the differential signal acquired in S211 and the minimum viscosity W2k. The viscosity estimation data for the black ink corresponding to the straight line L2k in FIG. 9B is generated. Further, in S314, the average value of the amplitude H1c of the differential signal acquired in S304, the average value of the pre-discharge viscosity W1c acquired in S309, the average value of the amplitude H2c of the differential signal acquired in S313, and the minimum viscosity W2c Based on this, viscosity estimation data for the color ink corresponding to the straight line L2c in FIG. 9B is generated.

Further, in the first modification, the viscosities of the black ink and the color ink are reduced to the minimum viscosities W2k and W2c by flushing, but the present invention is not limited to this. For example, by suction purging, either black ink or color ink can be selectively discharged, and by suction purging of black ink and color ink, the black ink and color ink in the inkjet head 4 can be ejected from the nozzle 10, respectively. May be gradually discharged to reduce the viscosity of the black ink and the color ink to the minimum viscosity W2k and W2c, respectively. In this case, the maintenance unit 8 that performs suction purging corresponds to the "discharge means" of the present invention.

Further, in the above-described embodiment, the detection signal output from the detection conductive unit 66 is differentiated in the differentiating circuit 68, but the present invention is not limited to this. In the second modification, the control device 80 performs the process according to the flow of FIG. 11 in the viscosity estimation data generation process.

More specifically, in the second modification, the control device 80 discharges black ink from the representative black nozzle as in S201 of the above-described embodiment (S401), and then the detection is output from the detection conductive portion 66. The signal is differentiated to generate a differential signal (S402), and the amplitude H1k of the generated differential signal is acquired (S403). Further, the control device 80 generates a differential signal by differentiating the detection signal output from the detection conductive unit 66 after ejecting the color ink from the representative color nozzle as in S203 of the above-described embodiment (S404). Then (S405), the amplitude H1c of the generated differential signal is acquired (S406).

Further, the control device 80 generates a differential signal by differentiating the detection signal output from the detection conductive unit 66 after ejecting black ink from the representative black nozzle (S412) as in S210 of the above-described embodiment. (S413), and the amplitude H2k of the generated differential signal is acquired (S414). Further, the control device 80 generates a differential signal by differentiating the detection signal output from the detection conductive unit 66 after ejecting the color ink from the representative color nozzle as in S212 of the above-described embodiment (S415). (S416), and the amplitude H2c of the generated differential signal is acquired (S417).

That is, in the second modification, the control device 80 differentiates the detection signal output from the detection conductive unit 66 to generate a differential signal. In S402, S405, S413, and S416, for example, the control device 80 differentiates the detection signal in the second order as in the differentiating circuit 68 of the above-described embodiment. Alternatively, the control device 80 may differentiate the detection signal into the first derivative or the third derivative or higher. Further, since S407 to S411 and S418 of the second modification are the same as S205 to S209 and S214 of the above-described embodiment, respectively, description thereof will be omitted here.

Further, in the above example, when ink is ejected from the nozzle 10, the inside of the nozzle 10 is based on the amplitude of the differential signal obtained by differentiating the detection signal output from the detection conductive portion 66 and the viscosity estimation data. The viscosity of the was estimated, but not limited to this. For viscosity estimation of the signal itself output from the detection conductive unit 66 or the signal obtained by processing the signal output from the detection conductive unit 66 other than differentiation, and the relationship between these signals and the viscosity of the ink. The viscosity of the ink in the nozzle 10 may be estimated based on the data.

Further, in this case, it is utilized that the inclination of the voltage change in the detection signal output from the detection conductive portion 66 when the ink is ejected from the nozzle 10 corresponds to the viscosity of the ink in the nozzle 10. Therefore, it is not limited to estimating the viscosity of the ink in the nozzle 10.

For example, in the third modification, as shown in FIG. 12A, a determination circuit 101 is connected to the detection conductive portion 66 instead of the differentiating circuit 68. Here, when the inkjet head 4 is controlled so that the ink is ejected from the nozzle 10, when the ink is ejected from the nozzle 10, as shown in FIG. 5A described above, the detection conductive portion 66 The voltage value of the detection signal output from is changed. On the other hand, when the ink is not ejected from the nozzle 10, the voltage value of the detection signal output from the detection conductive portion 66 hardly changes. The determination circuit 101 outputs a signal having a different value depending on whether or not a change of a predetermined amount or more has occurred in the voltage value of the signal output from the detection conductive unit 66. In this case, whether or not the ink is ejected from the nozzle 10 corresponds to the "ejection characteristic" of the present invention. Then, the method of changing the voltage value (electrical change) of the detection signal differs depending on whether or not the ink is ejected from the nozzle 10.

Further, in the third modification, as shown in FIG. 12B, the drive potentials Va to Vf (Va <Vb <Vc <Vd <Ve <Vf) applied to the individual electrodes 54 and the ink in the nozzle 10 Data in a table relating the viscosity Wa to Wd (Wa <Wb <Wc <Wd) and whether or not ink is ejected from the nozzle 10 when the inkjet head 4 is driven is stored in the flash memory 84. Has been done. “◯” in the table of FIG. 12B indicates that the value of the signal output from the determination circuit 101 is the value when the ink is ejected from the nozzle 10. Further, "x" in the table of FIG. 12B indicates that the value of the signal output from the determination circuit 101 is the value when the ink is not ejected from the nozzle 10. In the third modification, the table data as shown in FIG. 12B may be stored for each of the black ink and the color ink, or the ink color may be individually stored in FIG. 12B. The data of the table as shown in FIG. 12 may be stored, or only one data of the table as shown in FIG. 12B may be stored in common to the inks of all colors. Further, in the modified example 3, the data in the table as shown in FIG. 12B corresponds to the “viscosity estimation data” of the present invention.

Then, in the third modification, when estimating the viscosity of the ink in the nozzle 10, the control device 80 performs the process according to the flow of FIG. More specifically, the control device 80 first has the above-mentioned predetermined positional relationship between the carriage 2 and the cap 61 in the same manner as in S101 of the above-described embodiment (S501).

Subsequently, the control device 80 sets a target nozzle, which is a target for estimating the viscosity of the ink, from the plurality of nozzles 10 of the inkjet head 4 (S502). In S502, for example, among the plurality of nozzles 10 constituting the rightmost nozzle row 9 in the scanning direction, the most upstream nozzle 10 in the transport direction is set as the target nozzle. However, in S502, any nozzle 10 among the plurality of nozzles 10 of the inkjet head 4 may be set as the target nozzle.

Subsequently, the control device 80 sets the drive potential to the lowest Va among the Va to Vf of FIG. 12 (b) (S503). Then, the control device 80 drives the inkjet head 4 (S504) so as to eject the ink from the nozzle 10 whose viscosity is to be estimated, and the nozzle is based on the signal output from the determination circuit 101 at this time. It is determined whether or not the ink has been ejected from No. 10 (S505).

When ink is ejected from the nozzle 10 (S505: YES), the viscosity of the ink in the nozzle 10 is estimated based on the current drive potential and the table of FIG. 12 (b) (S506). For example, when the current drive potentials are Va, Vc, and Ve, the viscosities of the inks in the nozzle 10 are estimated to be Wa, Wb, and Wc, respectively. Further, when the current drive potentials are Vb, Vd, and Vf, the viscosity of the ink in the nozzle 10 is the viscosity between Wa and Wb (for example, [(Wa + Wb) / 2]), Wb and Wc, respectively. It is estimated to have a viscosity between (eg, [(Wb + Wc) / 2]) and a viscosity between Wc and Wd (eg, [(Wc + Wd) / 2]).

When no ink is ejected from the nozzle 10 (S505: NO), and when the current drive potential is the highest Vf among Va to Vf (S507: YES), the table shown in FIG. 12 (b) is displayed. Based on this, the viscosity of the ink in the nozzle 10 is estimated (S506). Specifically, the viscosity of the ink in the nozzle 10 is estimated to be Wd.

On the other hand, when the drive potential is other than Vf (S507: NO), the control device 80 changes the drive potential (S508) and returns to S504. In S508, the drive potential is changed from Vb to Vf to a potential one step higher than the current drive potential. That is, when the current drive potential is Va, Vb, Vc, Vd, Ve, the drive potential is raised to Vb, Vc, Vd, Ve, Vf, respectively.

Further, after the estimation of the viscosity of the ink in the nozzle 10 of S506, if the estimation of the viscosity of all the nozzles 10 of the inkjet head 4 is not completed (S509: NO), the nozzle 10 for which the viscosity is estimated is changed. Then (S510), the process returns to S503. In S510, for example, when the nozzle 10 for which the current viscosity is estimated is a nozzle 10 other than the nozzle 10 on the most downstream side in the transport direction among the plurality of nozzles 10 in any of the nozzle rows 9, the viscosity The nozzle 10 to be estimated is changed to a nozzle 10 adjacent to the downstream side in the transport direction of the nozzle 10 to be estimated for the current viscosity. Further, when the current nozzle 10 for which the viscosity is estimated is the nozzle 10 on the most downstream side in the transport direction among the plurality of nozzles 10 in any of the nozzle rows 9, the nozzle 10 for which the viscosity is estimated is used. Of the plurality of nozzles 10 constituting the nozzle row 9 adjacent to the left side of the nozzle row 9 including the nozzle 10 whose viscosity is currently estimated, the nozzle 10 is changed to the most upstream nozzle 10 in the transport direction. However, in S510, the nozzle 10 whose viscosity is to be estimated may be changed to any of the plurality of nozzles 10 of the inkjet head 4 whose viscosity has not been estimated.

Then, when the estimation of the viscosities of all the nozzles 10 of the inkjet head 4 is completed (S509: YES), the control device 80 is based on the estimated viscosities, and S511 to the same as S105 to S107 of the above-described embodiment. The process of S513 is executed.

Further, the "ejection characteristic" of the present invention may have characteristics different from those described above, such as the direction in which ink is ejected. Further, the detection signal output from the detection conductive portion has a different manner of changing the detection signal depending on the ink ejection characteristics, for example, the frequency of the detection signal changes depending on the ink ejection characteristics. It may be.

Further, in the above-described embodiment, the cap 61 is moved up and down so that the inkjet head 4 and the detection conductive portion 66 move relative to each other in the vertical direction, but the present invention is not limited to this. For example, the inkjet head 4 may move up and down, or both the inkjet head 4 and the cap 61 may move up and down, so that the inkjet head 4 and the detection conductive portion 66 move relative to each other in the vertical direction. In this case, a mechanism for raising and lowering the inkjet head 4 or a combination of a mechanism for raising and lowering the inkjet head 4 and a cap raising and lowering mechanism 88 constitutes the "relative moving means" of the present invention. become.

Further, in the above-described embodiment, the carriage 2 on which the inkjet head 4 is mounted moves in the scanning direction, so that the inkjet head 4 and the detection conductive portion 66 move relative to each other in the scanning direction. Not limited to. For example, the cap 61 moves in the scanning direction, or both the carriage 2 and the cap 61 move in the scanning direction, so that the inkjet head 4 and the detection conductive portion 66 move relative to each other in the scanning direction. You may. In this case, a mechanism for moving the cap 61 in the scanning direction, or a combination of a mechanism for moving the cap 61 in the scanning direction and the carriage 2 constitutes the "relative moving means" of the present invention. become.

Further, in the above-described embodiment, the ink in the inkjet head 4 is discharged from the plurality of nozzles 10 by suction purging, but the present invention is not limited to this. For example, a pressurizing pump may be provided in the middle of the tube 13 that connects the sub tank 3 and the ink cartridge 15. Alternatively, the printer may be provided with a pressurizing pump connected to the ink cartridge. Then, in a state where the plurality of nozzles 10 are covered with the caps 61, the pressurizing pump is driven to pressurize the ink in the inkjet head 4 and discharge the ink in the inkjet head 4 from the nozzles 10, so-called. Pressurized purging may be performed. In this case, the combination of the cap 61 and the pressurizing pump corresponds to the "purge means" of the present invention.

Further, in purging, both suction by the suction pump 62 and pressurization by the pressurizing pump may be performed. In this case, the combination of the maintenance unit 8 and the pressurizing pump corresponds to the "purge means" of the present invention.

Further, in the above-described embodiment, the setting at the time of recording on the recording paper P, the setting of the suction purge, and the setting of the flushing are performed based on the estimated viscosity of the ink in the nozzle 10. I can't. Only some of these settings may be made. Alternatively, the estimated viscosity of the ink in the nozzle 10 may be used for a purpose other than these.

Further, in the above-described embodiment, the viscosity of the ink in the nozzle 10 is estimated for each of the plurality of nozzles 10 based on the detection signal from the detection conductive portion 66 or the differential signal from the differentiating circuit 68. Not limited to. For example, for only some nozzles 10, the viscosity of the ink in the nozzle 10 is estimated based on the detection signal or the differential signal, and for the remaining nozzles 10, the viscosity estimated for some of the nozzles 10 is used. The viscosity may be estimated.

Further, in the above-described embodiment, the ink is discharged from the nozzle 10 by applying pressure to the ink in the pressure chamber 40 by the driving element 50, but the present invention is not limited to this. For example, the ink may be ejected from the nozzle by heating the ink to generate bubbles in the ink flow path.

Further, in the above-described embodiment, the inkjet head 4 is mounted on the carriage 2 and is a so-called serial type head that ejects ink from a plurality of nozzles 10 while moving in the scanning direction, but this is limited to this. I can't. For example, the inkjet head may be a so-called line head extending over the entire length of the recording paper P in the scanning direction.

Further, in the above, an example in which the present invention is applied to a printer that ejects ink from a nozzle and records on the recording paper P has been described, but the present invention is not limited thereto. It can also be applied to an image recording device that records an image on a recording medium other than recording paper, such as a T-shirt, a sheet for outdoor advertising, a case of a mobile terminal such as a smartphone, a corrugated cardboard, and a resin member. It can also be applied to a liquid ejection device that ejects a liquid other than ink, for example, a liquid resin or metal.

1 Printer 4 Inkjet head 8 Maintenance unit 10 Nozzle 61 Cap 66 Detection conductive part 67 High voltage power supply circuit 68 Differentiating circuit 69 Resistance 80 Control device 88 Cap lifting mechanism

Claims (15)

A liquid discharge head with a nozzle and
It has a conductive portion for detection, and is a signal of an electrical change generated in the conductive portion for detection by the liquid discharged from the nozzle, and the way of the electrical change depends on the discharge characteristic of the liquid from the nozzle. A signal output unit that outputs a detection signal that is a different signal,
With a control unit
The control unit
Viscosity estimation data relating to the relationship between the detection signal and the viscosity of the liquid in the nozzle, and the detection signal output from the signal output unit when the liquid discharge head is controlled to discharge the liquid from the nozzle. A liquid discharge device, characterized in that the viscosity of the liquid in the nozzle is estimated based on the above. The control unit
When the liquid discharge head is controlled to discharge the liquid from the nozzle toward the discharge medium,
The liquid discharge device according to claim 1, wherein the liquid discharge head is controlled based on the estimated viscosity of the liquid. A purging means for purging the liquid in the liquid discharging head from the nozzle is provided.
The control unit
The liquid discharge device according to claim 1 or 2, wherein the purging means is made to perform the purging based on the estimated viscosity of the liquid. The control unit
The liquid discharge device according to any one of claims 1 to 3, wherein the liquid discharge head is controlled to perform flushing to discharge the liquid from the nozzle based on the estimated viscosity of the liquid. The control unit
Generates a differential signal obtained by differentiating the detected signal to the first order or higher.
The viscosity estimation data is data relating to the relationship between the amplitude of the differential signal and the viscosity of the liquid in the nozzle.
The control unit
The viscosity estimation data and the amplitude of the differential signal generated based on the detection signal output from the signal output unit when the liquid discharge head is controlled to discharge the liquid from the nozzle. The liquid discharge device according to any one of claims 1 to 4, wherein the viscosity of the liquid in the nozzle is estimated based on the above. A differentiating circuit for generating a differential signal obtained by differentiating the detected signal to the first order or higher is provided.
The viscosity estimation data is data showing the relationship between the amplitude of the differential signal and the viscosity of the liquid in the nozzle.
The control unit
Of the differentiating signal generated by the differentiating circuit based on the viscosity estimation data and the detection signal output from the signal output unit when the liquid is discharged from the nozzle by controlling the liquid discharge head. The liquid discharge device according to any one of claims 1 to 4, wherein the viscosity of the liquid in the nozzle is estimated based on the amplitude. The control unit
The liquid discharge device according to any one of claims 1 to 6, wherein the viscosity estimation data is generated immediately before the viscosity of the liquid in the nozzle is estimated. A relative moving means for relatively moving the liquid discharge head and the detection conductive portion is provided.
The control unit
The viscosity estimation data is generated in a state where the liquid discharge head and the detection conductive portion are relatively moved to the relative moving means so as to have a predetermined positional relationship.
After that, while maintaining the liquid discharge head and the detection conductive portion in the predetermined positional relationship, the liquid discharge head is controlled to discharge the liquid from the nozzle.
The liquid discharge device according to claim 7, wherein the viscosity of the liquid in the nozzle is estimated based on the viscosity estimation data and the signal output from the signal output unit. A cap, which covers the nozzle, is provided.
The detection conductive portion is arranged in the cap,
The relative moving means moves the liquid discharge head and the cap relative to each other.
The liquid discharge device according to claim 8, wherein the predetermined positional relationship is a positional relationship in which the plurality of nozzles of the liquid discharge head and the detection conductive portion face each other. A relative moving means for relatively moving the liquid discharge head and the detection conductive portion is provided.
The control unit
When estimating the viscosity of the liquid in the nozzle,
During the period from the previous estimation of the viscosity of the liquid in the nozzle to the estimation of the viscosity of the liquid in the nozzle this time, the liquid discharge head and the detection conductive portion are relatively moved by the relative moving means. If not,
Any of claims 7 to 9, wherein the viscosity of the liquid in the nozzle is estimated this time by using the viscosity estimation data generated immediately before the estimation of the viscosity of the liquid in the nozzle last time. Liquid discharge device described in. The liquid discharge head has a plurality of the nozzles.
The control unit
The liquid discharge head is controlled to perform a first discharge operation of discharging a liquid from a representative nozzle which is one of a plurality of the nozzles.
After the first discharge operation, the liquid discharge head is controlled to perform flushing to discharge the liquid from the representative nozzle until the viscosity of the liquid in the representative nozzle drops to a predetermined viscosity.
After the flushing, the liquid discharge head is controlled to perform a second discharge operation of discharging the liquid from the representative nozzle.
Discharge amount data showing the relationship between the viscosity of the liquid in the nozzle and the discharge amount of the liquid from the nozzle, which is necessary to reduce the viscosity of the liquid in the nozzle to the predetermined viscosity, and discharge by the flushing. Based on the amount of liquid, the viscosity before discharge, which is the viscosity of the liquid in the representative nozzle immediately before the flushing, is calculated.
The detection signal output from the signal output unit when the first discharge operation is performed,
The calculated viscosity before discharge,
The detection signal output from the signal output unit when the second discharge operation is performed, and
The liquid discharge device according to any one of claims 1 to 10, wherein the viscosity estimation data is generated based on the predetermined viscosity. The control unit
Based on the viscosity estimation data and the detection signal output from the signal output unit when the liquid is discharged from each of the nozzles other than the representative nozzle by driving the liquid discharge head, the representative The liquid discharge device according to claim 9, wherein the viscosity of the liquid in the nozzle other than the nozzle is estimated. A discharge means for performing a discharge operation for discharging the liquid in the liquid discharge head from the nozzle is further provided.
The control unit
The liquid discharge head is controlled to perform the first discharge operation of discharging the liquid from the nozzle.
After the first discharge operation, the discharge means is controlled to perform the discharge operation until the viscosity of the liquid in the nozzle drops to the predetermined viscosity.
After the discharge operation, the liquid discharge head is controlled to perform a second discharge operation of discharging the liquid from the nozzle.
Discharge amount data showing the relationship between the viscosity of the liquid in the nozzle and the discharge amount of the liquid from the nozzle required to reduce the viscosity of the liquid in the nozzle to the predetermined viscosity, and discharge by the discharge operation. Based on the amount of the liquid to be discharged, the viscosity before discharge, which is the viscosity of the liquid in the nozzle immediately before the discharge operation, is calculated.
The detection signal output from the signal output unit when the first discharge operation is performed,
The calculated viscosity before discharge,
The detection signal output from the signal output unit when the second discharge operation is performed, and
The liquid discharge device according to any one of claims 1 to 6, wherein the viscosity estimation data is generated based on the predetermined viscosity. The liquid discharge head
Individual flow paths including the nozzle and
It has a drive element as the discharge means that applies pressure to the liquid in the individual flow path, and has.
The control unit
The liquid discharge device according to claim 13, wherein as the discharge operation, flushing is performed to drive the drive element to discharge the liquid in the liquid discharge head from the nozzle. The liquid discharge head serves as the nozzle.
The first nozzle that discharges the first liquid and
It has a second nozzle that discharges a second liquid different from the first liquid.
The control unit
The first viscosity estimation data, which is the viscosity estimation data relating to the relationship between the detection signal and the viscosity of the liquid in the first nozzle, and the liquid discharge head were controlled to discharge the liquid from the first nozzle. The viscosity of the liquid in the first nozzle is estimated based on the detection signal sometimes output from the signal output unit.
The second viscosity estimation data, which is the viscosity estimation data relating to the relationship between the detection signal and the viscosity of the liquid in the second nozzle, and the liquid discharge head were controlled to discharge the liquid from the second nozzle. The liquid discharge device according to any one of claims 1 to 14, characterized in that the viscosity of the liquid in the second nozzle is estimated based on the detection signal sometimes output from the signal output unit. ..

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