JP7105677B2 - liquid jet recorder - Google Patents

Description

The present disclosure relates to a liquid jet recording apparatus .

2. Description of the Related Art A liquid jet recording apparatus having a liquid jet head is used in various fields, and various types of liquid jet heads have been developed (for example, see Patent Document 1).

JP-A-10-114068

Such liquid jet recording apparatuses are required to improve productivity during printing operations. It is desirable to provide a liquid jet recording apparatus capable of improving productivity during printing operations.

A first liquid jet recording apparatus according to an embodiment of the present disclosure is an apparatus that performs a printing operation on a recording medium, and prints on the recording medium based on a drive signal having one or more pulses. It includes a liquid ejecting head that ejects liquid toward the target, a storage section that stores the liquid, and a print control section that controls a printing operation. The print control unit controls the frequency of a drive signal for printing one pixel on a recording medium according to the amount of gas dissolved in the liquid supplied from the storage unit toward the liquid jet head. When controlling the number of pulses per unit time, which is the number of pulses per unit time included in the drive signal, by controlling the frequency, if the amount of dissolved gas is less than the first threshold, the drive frequency is changed. When the dissolved gas amount is equal to or greater than the first threshold value and less than the second threshold value, the drive frequency is decreased from the specified value to a non-zero value (≠0). , the drive frequency is set to a zero value (=0) when the dissolved gas amount is greater than or equal to the second threshold .

A second liquid jet recording apparatus according to an embodiment of the present disclosure is an apparatus that performs a printing operation on a recording medium, and prints on the recording medium based on a drive signal having one or more pulses. A liquid jet head that jets liquid toward a target, a storage section that stores the liquid, a print control section that controls the printing operation, and relative movement between the liquid jet head and the recording medium at a predetermined moving speed. and a moving mechanism that allows The print control unit adjusts the frequency of the drive signal during the printing operation for one pixel on the recording medium according to the amount of gas dissolved in the liquid supplied from the storage unit toward the liquid jet head. By controlling the drive frequency, the number of pulses per unit time, which is the number of pulses included in the drive signal, is controlled. When controlling the speed, if the dissolved gas amount is less than the first threshold, the moving speed is maintained unchanged from the specified value, and the dissolved gas amount is the first threshold or more and the second threshold If it is less than, the moving speed is reduced from the specified value to a non-zero value (≠0), and if the dissolved gas amount is equal to or greater than the second threshold, the moving speed is reduced to a zero value (=0 ).

According to the first and second liquid jet recording apparatuses according to the embodiments of the present disclosure, it is possible to improve productivity during printing operations.

1 is a schematic perspective view showing a schematic configuration example of a liquid jet recording apparatus according to an embodiment of the present disclosure; FIG. 2 is a schematic diagram showing a schematic configuration example of the liquid jet head shown in FIG. 1; FIG. 3 is a schematic diagram showing a cross-sectional configuration example of a nozzle plate, an actuator plate, and the like shown in FIG. 2. FIG. FIG. 4 is a schematic cross-sectional view showing an enlarged part IV shown in FIG. 3 ; 4 is a timing chart schematically showing an example of waveforms of drive signals; FIG. 6 is a block diagram showing a detailed configuration example of a liquid jet recording apparatus including the liquid jet head shown in FIGS. 2 to 5; FIG. 5 is a flowchart showing an example of control processing during printing operation in the liquid jet recording apparatus according to the embodiment; It is a figure showing the experimental result which concerns on Experimental example 1,2. FIG. 11 is a block diagram showing a configuration example of a liquid jet recording apparatus according to a modified example;

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order.
1. Embodiment (Example of Liquid Jet Recording Apparatus Controlling Driving Frequency etc. According to Dissolved Gas Amount)
2. Modified Example (Example of Controlling Drive Frequency etc. According to Dissolved Gas Amount in Liquid Jet Head)
3. Other variations

<1. Embodiment>
[A. Overall Configuration of Printer 1]
FIG. 1 is a schematic perspective view of a schematic configuration example of a printer 1 as a liquid jet recording apparatus according to an embodiment of the present disclosure. The printer 1 is an inkjet printer that uses ink 9, which will be described later, to record (print) images, characters, and the like on recording paper P as a recording medium.

The printer 1 includes a pair of transport mechanisms 2a and 2b, an ink tank 3, an inkjet head 4, an ink supply pipe 50, and a scanning mechanism 6, as shown in FIG. Each of these members is housed in a housing 10 having a predetermined shape. In addition, in each drawing used for the description of this specification, the scale of each member is appropriately changed so that each member has a recognizable size.

Here, the printer 1 corresponds to a specific example of a "liquid jet recording apparatus" in the present disclosure, and the inkjet heads 4 (inkjet heads 4Y, 4M, 4C, 4K to be described later) are "liquid jet heads" in the present disclosure. corresponds to a specific example of Further, the ink tanks 3 (ink tanks 3Y, 3M, 3C, and 3K to be described later) correspond to a specific example of the "accommodating portion" in the present disclosure, and the ink 9 is a specific example of the "liquid" in the present disclosure. Yes.

Each of the transport mechanisms 2a and 2b is a mechanism for transporting the recording paper P along the transport direction d (X-axis direction), as shown in FIG. Each of these transport mechanisms 2a and 2b has a grid roller 21, a pinch roller 22 and a drive mechanism (not shown). This driving mechanism is a mechanism for rotating the grid roller 21 around its axis (rotating within the ZX plane), and is composed of, for example, a motor.

(ink tank 3)
The ink tank 3 is a tank that contains ink 9 therein. In this example, as shown in FIG. 1, the ink tank 3 contains four inks 9 of yellow (Y), magenta (M), cyan (C), and black (K). There are different types of tanks. That is, an ink tank 3Y containing yellow ink 9, an ink tank 3M containing magenta ink 9, an ink tank 3C containing cyan ink 9, and an ink tank 3K containing black ink 9 are provided. is provided. These ink tanks 3Y, 3M, 3C, and 3K are arranged side by side along the X-axis direction within the housing 10. As shown in FIG.

Note that the ink tanks 3Y, 3M, 3C, and 3K have the same configuration except for the color of the ink 9 contained therein, so that they will be collectively referred to as the ink tank 3 below.

(inkjet head 4)
The inkjet head 4 is a head that ejects droplets of ink 9 onto the recording paper P from a plurality of nozzles (nozzle holes Hn), which will be described later, to record (print) images, characters, and the like. . In this example, as shown in FIG. 1, the ink jet head 4 also includes four types of heads that individually eject the four color inks 9 contained in the ink tanks 3Y, 3M, 3C, and 3K. is provided. That is, an inkjet head 4Y that ejects yellow ink 9, an inkjet head 4M that ejects magenta ink 9, an inkjet head 4C that ejects cyan ink 9, and an inkjet head 4K that ejects black ink 9 are provided. is provided. These inkjet heads 4Y, 4M, 4C, and 4K are arranged side by side along the Y-axis direction within the housing 10 .

Since the inkjet heads 4Y, 4M, 4C, and 4K have the same configuration except for the color of the ink 9 to be used, they will be collectively referred to as the inkjet head 4 below. A detailed configuration example of the inkjet head 4 will be described later (FIGS. 2 to 5).

The ink supply pipe 50 is a pipe through which the ink 9 is supplied from the ink tank 3 toward the inkjet head 4 . The ink supply pipe 50 is composed of, for example, a flexible hose that is flexible enough to follow the operation of the scanning mechanism 6 described below.

(scanning mechanism 6)
The scanning mechanism 6 is a mechanism for scanning the inkjet head 4 along the width direction of the recording paper P (Y-axis direction). As shown in FIG. 1, the scanning mechanism 6 includes a pair of guide rails 61a and 61b extending along the Y-axis direction, and a carriage 62 movably supported by these guide rails 61a and 61b. , and a driving mechanism 63 for moving the carriage 62 along the Y-axis direction.

The drive mechanism 63 includes a pair of pulleys 631a and 631b arranged between the guide rails 61a and 61b, an endless belt 632 wound between the pulleys 631a and 631b, and a drive motor 633 for rotating the pulley 631a. and have Also, on the carriage 62, the above-described four types of inkjet heads 4Y, 4M, 4C, and 4K are arranged side by side along the Y-axis direction.

A moving mechanism for relatively moving the inkjet head 4 and the recording paper P at a predetermined moving speed (for example, a transporting speed Vt to be described later) by the scanning mechanism 6 and the transporting mechanisms 2a and 2b described above. is configured. That is, the scanning mechanism 6 and the transport mechanisms 2a and 2b correspond to one specific example of the "moving mechanism" in the present disclosure.

[B. Detailed Configuration of Inkjet Head 4]
Next, a detailed configuration example of the inkjet head 4 will be described with reference to FIGS. 2 to 5. FIG.

FIG. 2 schematically shows an example of the schematic configuration of the inkjet head 4. As shown in FIG. FIG. 3 schematically shows a cross-sectional configuration example (ZX cross-sectional configuration example) of the nozzle plate 41, the actuator plate 42, etc. shown in FIG. FIG. 4 is an enlarged schematic cross-sectional view (ZX cross-sectional view) of the IV portion shown in FIG.

The inkjet head 4 is a so-called side shoot type inkjet head that ejects the ink 9 from the central portion in the extending direction (Y-axis direction) of a plurality of channels (channel C1) described later. The inkjet head 4 has a nozzle plate 41, an actuator plate 42, a cover plate 43, and a drive section 49, as shown in FIGS.

Here, the nozzle plate 41 and the actuator plate 42 correspond to one specific example of the "injector" in the present disclosure.

The nozzle plate 41, the actuator plate 42, and the cover plate 43 are attached to each other using an adhesive or the like, and are stacked in this order along the Z-axis direction (see FIGS. 3 and 4). Further, a channel plate (not shown) having a predetermined channel may be provided on the upper surface of the cover plate 43 .

(Nozzle plate 41)
The nozzle plate 41 is a plate made of a film material such as polyimide or a metal material, and has a plurality of nozzle holes Hn for ejecting the ink 9 (see dashed arrows in FIGS. 2 to 4). These nozzle holes Hn are arranged in a straight line (along the X-axis direction in this example) at predetermined intervals. Each nozzle hole Hn is a tapered through hole whose diameter gradually decreases downward (see FIGS. 2 to 4).

(Actuator plate 42)
The actuator plate 42 is a plate made of a piezoelectric material such as PZT (lead zirconate titanate). The actuator plate 42 is composed of one (single) piezoelectric substrate (so-called cantilever type) whose polarization direction is set in one direction along the thickness direction (Z-axis direction). However, the configuration of the actuator plate 42 is not limited to this cantilever type. That is, for example, the actuator plate 42 may be configured by stacking two piezoelectric substrates with different polarization directions along the thickness direction (Z-axis direction) (so-called chevron type).

The actuator plate 42 is provided with a plurality of channels C1 as shown in FIG. These channels C1 are arranged side by side along the X-axis direction so as to be parallel to each other with a predetermined interval. Each channel C1 is defined by a drive wall Wd made of a piezoelectric material, and forms a recessed groove when viewed in cross section (see FIGS. 3 and 4). Each drive wall Wd functions as an element (piezoelectric element) for individually pressurizing the inside of each channel C1 (each discharge channel C1e, which will be described later), although details will be described later.

As shown in FIGS. 3 and 4, the channel C1 includes an ejection channel C1e for ejecting the ink 9 and a dummy channel (non-ejection channel) C1d for not ejecting the ink 9. there is In other words, the ejection channel C1e is filled with the ink 9, while the dummy channel C1d is not filled with the ink 9. Each ejection channel C1e communicates with the nozzle hole Hn in the nozzle plate 41, while each dummy channel C1d does not communicate with the nozzle hole Hn. These ejection channels C1e and dummy channels C1d are alternately arranged along a predetermined direction (the X-axis direction in this example) within the actuator plate 42 via the drive wall Wd ( See Figure 3).

As shown in FIG. 3, drive electrodes Ed are provided on the opposing inner side surfaces of the drive wall Wd described above. That is, a pair of drive electrodes Ed are arranged to face each other with each drive wall Wd interposed therebetween. The drive electrodes Ed include a common electrode Edc (common electrode) provided on the inner surface facing the ejection channel C1e and an individual electrode Eda (active electrode) provided on the inner surface facing the dummy channel C1d. exists (see FIGS. 3 and 4). In other words, the common electrode Edc as the drive electrode Ed is individually formed inside each discharge channel C1e, and the individual electrode Eda as the drive electrode Ed is individually formed inside each dummy channel C1d. .

The drive electrodes Ed and the drive circuit on the drive substrate (not shown) are electrically connected via a plurality of extraction electrodes formed on the flexible substrate (not shown). Thus, a driving voltage Vd (driving signal Sd), which will be described later, is applied to each driving electrode Ed from a driving circuit including a driving section 49, which will be described later, via the flexible substrate.

(Cover plate 43)
The cover plate 43 is arranged to close each channel C1 in the actuator plate 42, as shown in FIGS. Specifically, the cover plate 43 is adhered to the upper surface of the actuator plate 42 and has a plate-like structure.

(Driving unit 49)
The driving unit 49 drives the actuator plate 42 to perform ejection driving so that the ink 9 filled in the ejection channels C1e is ejected from the nozzle holes Hn (see FIGS. 2 to 4). . Specifically, the driving section 49 applies the above-described driving voltage Vd (driving signal Sd) to the actuator plate 42 to expand or contract the ejection channel C1e, thereby ejecting the ink 9 from each nozzle hole Hn. It is designed to inject (perform an injecting operation).

Here, FIGS. 5A to 5C are schematic timing diagrams of such waveform examples of the driving signal Sd. As will be described below, this drive signal Sd is a signal having one or more pulses. In FIGS. 5A to 5C, the horizontal axis indicates time t, and the vertical axis indicates drive voltage Vd (positive voltage in this example) in drive signal Sd.

First, the driving signal Sd shown in FIG. 5A has one pulse, and is an example of so-called "one drop". This pulse has an ON period ("ON" pulse width) provided between the rising timing and the falling timing.

On the other hand, the drive signal Sd shown in FIG. 5(B) has the following two pulses as pulses to which the so-called "multi-pulse method" is applied (an example of the so-called "2-drop" case). That is, two such pulses are provided: a first ON period (“ON1” pulse width) and a second ON period (“ON2” pulse width).

Similarly, the driving signal Sd shown in FIG. 5(C) has the following three pulses as pulses to which the above-described "multi-pulse method" is applied (an example of so-called "three-drop" ). That is, such pulses include a first ON period (“ON1” pulse width), a second ON period (“ON2” pulse width), and a third ON period (“ON3” pulse width). pulse width) and .

Each pulse in these drive signals Sd becomes a positive pulse that expands the above-described ejection channel C1e during the high state period and contracts the ejection channel C1e during the low state period. there is

Here, in the drive signals Sd shown in FIGS. 5A to 5C, the drive period Td contributing to ejection of the ink 9 is the above-described "ON" period, "ON2" period, " ON3” period and the like. Therefore, the drive frequency fd in the drive signal Sd is the reciprocal of this drive cycle Td (fd=1/Td). The number of pulses per unit time (see FIGS. 5A to 5C) included in such drive signal Sd is hereinafter referred to as the number of pulses per unit time Np. In other words, the drive frequency fd described above corresponds to the frequency of the drive signal Sd during the printing operation for one pixel on the recording medium (recording paper P). It should be noted that this "driving signal Sd for printing operation for one pixel" is not only the waveform for "1 drop" as shown in FIGS. It means one drive signal including waveforms in the case of "multi-drop" such as "2-drop" and "3-drop".

[C. Detailed Configuration of Printer 1]
Next, a detailed configuration example of the printer 1 will be described with reference to FIG. FIG. 6 is a block diagram showing a detailed configuration example of the printer 1 including the inkjet head 4 shown in FIGS. 2 to 4. As shown in FIG.

The printer 1 of the present embodiment includes a degassing device 11, a dissolved oxygen amount measuring unit 12 and a printing control unit as shown in FIG. 13 (head controller). In the example of FIG. 6, along with the degassing device 11, the dissolved oxygen amount measuring section 12, and the printing control section 13, the conveying mechanisms 2a and 2b, the ink tank 3, and the inkjet head 4 are shown.

(Deaerator 11)
As shown in FIG. 6, the degassing device 11 degasses the ink 9 when supplying the ink 9 from the ink tank 3 to the inkjet head 4 (on the path of the ink supply pipe 50 described above). It is a device that performs air treatment. Specifically, the degassing device 11 removes (degases) gas dissolved in the ink 9 (for example, oxygen (O ₂ ), etc.).

(Dissolved oxygen measurement unit 12)
As shown in FIG. 6, the dissolved oxygen amount measuring unit 12 measures the amount of oxygen (dissolved oxygen amount DO) dissolved in the ink 9 after the degassing process by the deaerator 11 has been performed. It is something to do. Information on the dissolved oxygen amount DO measured by the dissolved oxygen amount measuring unit 12 in this manner is output to the later-described print control unit 13 in the printer 1 of the present embodiment.

Here, the dissolved oxygen amount measuring unit 12 corresponds to a specific example of the "measuring unit" in the present disclosure. Also, the dissolved oxygen amount DO corresponds to a specific example of the "dissolved gas amount" in the present disclosure.

(Print control unit 13)
The print control unit 13 controls printing operations in the printer 1 and controls various members in the printer 1 . Specifically, as shown in FIG. 6, the print control unit 13 sends the print data Dp, the unit time pulse number Np and the drive frequency fd to the inkjet head 4 (drive unit 49, which will be described later). and , respectively. The print control unit 13 also supplies a signal (conveyance speed control signal Sc) for controlling the conveyance speed Vt of the recording paper P in the conveyance mechanisms 2a and 2b to these conveyance mechanisms 2a and 2b (see FIG. 6). . At the same time, the print control unit 13 acquires a detection signal (conveyance speed detection signal Svt) of the actual conveying speed Vt in the conveying mechanisms 2a and 2b from these conveying mechanisms 2a and 2b (see FIG. 6). ).

Here, in the present embodiment, the print control unit 13 controls the unit time pulse number Np is designed to control Specifically, as shown in FIG. 6, the print control unit 13 controls the unit time pulse number Np according to the dissolved oxygen amount DO measured by the dissolved oxygen amount measurement unit 12 described above. At this time, the print control unit 13 controls the unit time pulse number Np by controlling the drive frequency fd according to the dissolved oxygen amount DO.

Further, along with such control of the driving frequency fd, the print control unit 13 adjusts the moving speed of the moving mechanism described above (relative moving speed between the inkjet head 4 and the recording paper P) according to the dissolved oxygen amount DO. to control. Specifically, in this example, as shown in FIG. 6, the print control unit 13 uses the above-described transport speed control signal Sc to control the transport speed Vt in the transport mechanisms 2a and 2b. .

Further, the print control unit 13 obtains the above-described transport speed detection signal Svt, and controls the drive frequency fd while confirming the transport speed detection signal Svt (the actual transport speed Vt in the transport mechanisms 2a and 2b). (See Fig. 6).

Details of various controls in the print control unit 13 will be described later (FIG. 7).

Here, the transport speed Vt described above corresponds to a specific example of the "moving speed" in the present disclosure. Further, the conveying speed detection signal Svt described above corresponds to a specific example of the “conveying speed detection signal” in the present disclosure.

[Operation and action/effect]
(A. Basic operation of printer 1)
In the printer 1, a recording operation (printing operation) of images, characters, etc. on the recording paper P is performed in the following manner. In the initial state, it is assumed that the four types of ink tanks 3 (3Y, 3M, 3C, and 3K) shown in FIG. . Further, the ink 9 in the ink tank 3 is in a state of filling the ink jet head 4 through the ink supply pipe 50 .

When the printer 1 is operated in such an initial state, the grid rollers 21 in the transport mechanisms 2a and 2b rotate, so that the recording paper P is placed between the grid rollers 21 and the pinch rollers 22 in the transport direction d (X axial direction). Simultaneously with such a conveying operation, the drive motor 633 in the drive mechanism 63 rotates the pulleys 631a and 631b, respectively, thereby operating the endless belt 632. As shown in FIG. As a result, the carriage 62 reciprocates along the width direction of the recording paper P (Y-axis direction) while being guided by the guide rails 61a and 61b. At this time, the inkjet heads 4 (4Y, 4M, 4C, and 4K) appropriately eject four colors of ink 9 onto the recording paper P, thereby recording images, characters, and the like on the recording paper P. be.

(B. Detailed operation in inkjet head 4)
Next, a detailed operation (ejection operation of the ink 9) in the inkjet head 4 will be described. That is, in this inkjet head 4, the ejection operation of the ink 9 using the shear mode is performed as follows.

First, the drive section 49 applies a drive voltage Vd (drive signal Sd) to the drive electrodes Ed (common electrode Edc and individual electrodes Eda) in the actuator plate 42 (see FIGS. 2 to 6). Specifically, the drive unit 49 applies the drive voltage Vd to each drive electrode Ed (common electrode Edc and individual electrode Eda) arranged on a pair of drive walls Wd that define the ejection channel C1e. As a result, the pair of drive walls Wd are deformed so as to protrude toward the dummy channel C1d adjacent to the ejection channel C1e.

At this time, the drive wall Wd bends and deforms in a V shape centering on the intermediate position in the depth direction of the drive wall Wd. Due to such bending deformation of the driving wall Wd, the ejection channel C1e is deformed as if it is expanding (see the expansion direction da shown in FIG. 4). In this manner, the volume of the discharge channel C1e increases due to bending deformation due to the piezoelectric thickness slip effect in the pair of drive walls Wd. As the volume of the ejection channel C1e increases, the ink 9 is guided into the ejection channel C1e.

Next, the ink 9 guided into the ejection channel C1e in this way becomes a pressure wave and propagates inside the ejection channel C1e. Then, the driving voltage Vd applied to the driving electrode Ed becomes 0 (zero) V at the timing when the pressure wave reaches the nozzle hole Hn of the nozzle plate 41 (or at the timing near it). As a result, the drive wall Wd is restored from the bending deformation state described above, and as a result, the volume of the discharge channel C1e, which has increased once, returns to its original volume (see the contraction direction db shown in FIG. 4).

In this manner, the pressure inside the ejection channel C1e increases and the ink 9 inside the ejection channel C1e is pressurized in the process of restoring the volume of the ejection channel C1e. As a result, ink droplets 9 are ejected to the outside (toward the recording paper P or the like) through the nozzle holes Hn (see FIGS. 2 to 4 and 6). In this manner, the ink 9 is ejected from the inkjet head 4, and as a result, an image, characters, or the like is recorded on the recording paper P (printing operation).

(C. Control processing of printing operation according to dissolved oxygen amount DO in ink 9)
Next, referring to FIG. 7 in addition to FIGS. 1 to 6, control processing (the above-described unit time pulse number Np , driving frequency fd, conveying speed Vt, etc.) will be described in detail.

FIG. 7 is a flow chart showing an example of control processing during printing operation in the printer 1 of the present embodiment.

In the series of processes shown in FIG. 7, first, the dissolved oxygen amount DO in the ink 9 after the degassing process in the deaerator 11 is measured in the dissolved oxygen amount measuring unit 12 (step S101). Next, the print control unit 13 determines whether the dissolved oxygen amount DO thus measured is less than a predetermined threshold value Dth1 (DO<Dth1) (step S102).

Here, when it is determined that the dissolved oxygen amount DO is less than the threshold value Dth1 (step S102: Y), this corresponds to the fact that the dissolved oxygen amount DO in the ink 9 is relatively small, and the print control unit 13 sets the drive frequency fd and the transport speed Vt as follows. That is, the print control unit 13 maintains (does not change) the driving frequency fd and the transport speed Vt at the predetermined specified values fdH and VtH (original values), respectively (step S103). In addition, after that, it will progress to step S107 mentioned later.

On the other hand, if it is determined that the dissolved oxygen amount DO is equal to or greater than the threshold value Dth1 (DO≧Dth1) (step S102: N), then the print control unit 13 makes the following determinations. That is, the print control unit 13 determines whether the dissolved oxygen amount DO is less than a threshold Dth2 (>Dth1) greater than the threshold Dth1 (DO<Dth2) (step S104).

Note that the thresholds Dth1 and Dth2 described above correspond to specific examples of the "first threshold" and the "second threshold" in the present disclosure, respectively. Further, the threshold Dth1 is, for example, about 1.0 to 3.0 [mg/L], and the threshold Dth2 is, for example, about 3.0 to 5.0 [mg/L].

Here, when it is determined that the dissolved oxygen amount DO is less than the threshold value Dth2 (Dth1≦DO<Dth2) (step S104: Y), the dissolved oxygen amount DO in the ink 9 is relatively medium. Correspondingly, the print control unit 13 controls the drive frequency fd and the transport speed Vt as follows. That is, the print control unit 13 lowers the drive frequency fd and the transport speed Vt from the specified values fdH and VtH to the non-zero values fdL and VtL (≠0), respectively (step S105). In addition, after that, it will progress to step S107 mentioned later.

On the other hand, when it is determined that the dissolved oxygen amount DO is equal to or greater than the threshold value Dth2 (DO≧Dth2) (step S104: N), this corresponds to the fact that the dissolved oxygen amount DO in the ink 9 is relatively large. , the print control unit 13 controls the drive frequency fd and the transport speed Vt as follows. That is, the print control unit 13 reduces the drive frequency fd and the transport speed Vt from the above-described specified values fdH and VtH to zero (=0), respectively (step S106). In other words, the print control unit 13 sets the drive frequency fd and the transport speed Vt to "0" to control the printing operation of the printer 1 (the ejection operation of the ink 9 from the inkjet head 4 and the transport mechanisms 2a and 2b). ) is stopped. In this case, the series of processing (control processing during printing operation) shown in FIG. 7 ends.

Here, after steps S103 and S105 described above, the print control unit 13 acquires the above-described transport speed detection signal Svt (detection signal of the actual transport speed Vt) from the transport mechanisms 2a and 2b (step S107). . While confirming the transport speed detection signal Svt, the print control unit 13 performs control processing (control processing for unit time pulse number Np, drive frequency fd, and transport speed Vt) during the printing operation of the printer 1 described above. . In other words, the print control unit 13 supplies the print data Dp, the unit time pulse number Np, and the drive frequency fd to the drive unit 49, respectively, to control the ejection operation of the ink 9 from the inkjet head 4 (see FIG. 6). At the same time, the print control unit 13 supplies the transport speed control signal Sc to the transport mechanisms 2a and 2b to control the transport operation of the recording paper P in the transport mechanisms 2a and 2b. In this manner, the print control unit 13 causes the printer 1 to perform the printing operation (step S108).

With this, the series of processing (control processing during the printing operation) shown in FIG. 7 ends.

(D. action and effect)
In this manner, in the printer 1 of the present embodiment, the unit time pulse number Np is controlled according to the dissolved oxygen amount DO in the ink 9, so that the jetting operation (printing operation) of the ink 9 is It comes to be appropriately controlled according to DO.

Here, in printers (liquid jet recording apparatuses), in general, as the number of pulses per unit time Np increases (the number of times the drive wall is driven for each of the plurality of nozzle holes in the inkjet head increases), the ink is discharged more frequently. Because of the agitation, dissolved gas (for example, dissolved oxygen) in the ink easily changes to bubbles. In particular, in inkjet printers compatible with water-based inks, there is a tendency for air bubbles to occur more frequently than solvent-based inks due to the effects of surfactants contained in water-based inks. If a large number of bubbles are generated in the ink in this manner, the ink jetting operation becomes unstable, and the printing image quality may deteriorate. However, if the printing operation itself is stopped when a large number of bubbles are generated in the ink, the productivity will be lowered.

On the other hand, in the present embodiment, for example, by controlling the unit time pulse number Np to decrease, air bubbles are generated in the ink 9 even when the dissolved oxygen amount DO in the ink 9 is large. It is possible to operate the inkjet head 4 while suppressing the That is, the printing operation can be continued without stopping within a range in which the generation of air bubbles in the ink 9 can be suppressed. As a result, in this embodiment, it is possible to improve the productivity during the printing operation.

(Experimental examples 1 and 2)
Here, FIG. 8 shows experimental results according to Experimental Examples 1 and 2 of the present embodiment. Specifically, in FIG. 8, each measured value of the dissolved oxygen amount DO (=0.9, 1.3, 1.8, 2.2, 2.5, 3.0, 3.3, 3. 5 and 3.7 [mg/L]), the print image quality determination results in Experimental Examples 1 and 2 are shown, respectively. In experimental example 1, the driving frequency fd is set to 5 [kHz] (low frequency), and in experimental example 2, the driving frequency fd is set to 10 [kHz] (high frequency). Incidentally, in these Experimental Examples 1 and 2, the environmental temperature was set to 25 [° C.], and general water-based pigment ink was used.

Here, in Experimental Examples 1 and 2, in detail, the following procedures (1) to (4) were performed.
(1) A degassing device is used to degas the ink, and the degassed ink is stored in a predetermined container (a container of 500 [mL]).
(2) The ink in the container (the ink after the degassing process) is supplied to an inkjet head ("508GS manufactured by SII Printec"), and the ink is continuously ejected from the inkjet head.
(3) During such an ink ejection operation (ejection operation), the entire nozzle hole is observed every two minutes to confirm the occurrence of "nozzle missing".
(4) Depending on the number of "missing nozzles", the print image quality is determined in three stages (○ (A), Δ (B), × (C)). In addition, if it becomes impossible to measure clearly due to dripping of ink droplets, etc., the confirmation work of the above-mentioned "nozzle clogging" occurrence status is terminated halfway (the maximum measurement time was set to 20 minutes). ).

Further, the details of the determination of the three levels of print image quality are specifically as follows. Some of the determination results in Experimental Example 2 shown in FIG. 8 correspond to the above-described cases in which measurement cannot be clearly performed (cases in which confirmation work is terminated in the middle), and are indicated by "-".
・"○ (A)": No "nozzle missing" occurred (normal printing operation is possible)
・"△ (B)": Several missing nozzles occur (printing is possible depending on the situation)
・“X (C)” … Many “nozzle missing” occurrences (in block units) (printing operation impossible)

In Experimental Examples 1 and 2 shown in FIG. 8, in both Experimental Examples 1 and 2, determination is made in the order of ○ (A), Δ (B), and × (C) as the dissolved oxygen amount DO increases. It can be seen that the results change and the print quality gradually deteriorates. That is, as described above, it was confirmed that when the amount DO of dissolved oxygen in the ink (bubbles generated in the ink) increases, the ink jetting operation becomes unstable and the print quality deteriorates. Comparing Experimental Examples 1 and 2, Experimental Example 1, in which the drive frequency fd is set relatively low, has a higher print quality than Experimental Example 2, in which the drive frequency fd is set relatively high. It can be seen that the degree of deterioration is moderately suppressed. That is, as described above, by controlling the drive frequency fd as the unit time pulse number Np to decrease, even when the dissolved oxygen amount DO in the ink is large, the generation of air bubbles in the ink can be suppressed. , it was confirmed that the printing operation can be continued.

Also, in this embodiment, the unit time pulse number Np is controlled by controlling the drive frequency fd, so that the unit time pulse number Np can be easily adjusted. As a result, it is possible to easily improve the productivity during the printing operation.

Furthermore, in the present embodiment, along with such control of the drive frequency fd, the relative moving speed (conveyance speed Vt) between the inkjet head 4 and the recording paper P is also controlled according to the dissolved oxygen amount DO. As a result, the ejecting operation (printing operation) of the ink 9 can be controlled more appropriately. Specifically, for example, when the drive frequency fd is controlled to decrease as described above, the movement speed is also controlled to decrease accordingly, thereby suppressing the decrease in print resolution ( preferably avoided). As a result, it is possible to suppress deterioration in print image quality while improving productivity during the printing operation.

In addition, in the present embodiment, when the dissolved oxygen amount DO is less than the threshold value Dth1 (relatively small amount), the driving frequency fd and the moving speed (conveying speed Vt) are set to the specified values fdH and VtH (originally ) is maintained, the original print image quality is ensured. Further, when the dissolved oxygen amount DO is equal to or more than the threshold value Dth1 and less than the threshold value Dth2 (relatively medium amount), the drive frequency fd and the transport speed Vt are decreased from the specified values fdH and VtH to the non-zero values fdL and VtL, respectively. After that, the printing operation is performed, so the following is performed. That is, the printing speed is reduced to such an extent that nozzle dropout due to air bubbles in the ink 9 does not occur, and the printing operation can be continued without stopping. On the other hand, when the dissolved oxygen amount DO is equal to or greater than the threshold value Dth2 (relatively large amount), the drive frequency fd and the transport speed Vt are each set to a zero value (“0”), and the printing operation is stopped. from the following: That is, when the print image quality is significantly degraded due to nozzle missing caused by air bubbles in the ink 9, waste due to unnecessary printing operations is avoided, and a decrease in productivity is prevented. As described above, it is possible to suppress deterioration in print image quality while improving productivity during the printing operation.

Further, in the present embodiment, as a moving mechanism for relatively moving the inkjet head 4 and the recording paper P, the transporting mechanisms 2a and 2b for transporting the recording paper P are included, and the above-described moving speed is set to Since the transport speed of the recording paper P in the transport mechanisms 2a and 2b is Vt, the following is obtained. That is, in a printer (liquid jet recording apparatus) of a type that performs a printing operation by moving at least the recording paper P side, it is possible to improve the productivity during the printing operation.

Furthermore, in the present embodiment, the drive frequency fd is controlled while checking the detection signal of the transport speed Vt (transport speed detection signal Svt), so the actual transport speed Vt in the transport mechanisms 2a and 2b is considered. After that, the drive frequency fd can be controlled with high accuracy. As a result, it is possible to further improve the productivity during the printing operation.

In addition, in the present embodiment, the dissolved oxygen amount DO in the ink 9 after degassing by the deaerator 11 is measured, and the dissolved oxygen amount DO thus measured is , the unit time pulse number Np is controlled, so the following is obtained. That is, the ejection operation (printing operation) of the ink 9 is controlled more appropriately (timely) according to the dissolved oxygen amount DO at each moment. As a result, it is possible to further improve the productivity during the printing operation.

<2. Variation>
Next, a modification of the above embodiment will be described. In addition, the same code|symbol is attached|subjected to the same thing as the component in embodiment, and description is abbreviate|omitted suitably.

[A. Constitution]
FIG. 9 is a block diagram showing an example configuration of a printer 1A as a liquid jet recording apparatus according to a modification. In the printer 1A of this modified example, the inkjet head 4A is provided in place of the inkjet head 4 in the printer 1 (see FIG. 6) of the embodiment, and a print control section 13A is provided in place of the print control section 13. correspond to things.

The inkjet head 4A corresponds to a specific example of "liquid jet head" in the present disclosure.

As shown in FIG. 9, this modified inkjet head 4A corresponds to the inkjet head 4 (see FIG. 6) of the embodiment in which a head controller 48 is further provided.

Here, in the printer 1A of this modified example, unlike the printer 1 of the embodiment (see FIG. 6), the dissolved oxygen amount DO measured by the dissolved oxygen amount measuring unit 12 is measured by the inkjet It is designed to be supplied into the head 4A (head control section 48 described above) (see FIG. 9).

(Head controller 48)
The head control section 48 controls the operation of the inkjet head 4A (driving section 49). Specifically, as shown in FIG. 9, the head control unit 48 controls the dissolved oxygen amount DO (measured by the dissolved oxygen amount measuring unit 12) in the ink 9 supplied from the ink tank 3 toward the inkjet head 4A. The unit time pulse number Np is controlled according to the dissolved oxygen amount DO). Information on the unit time pulse number Np controlled by the head controller 48 in this manner is output to the drive unit 49 in the inkjet head 4A and the print controller 13A ( See Figure 9).

(Print control unit 13A)
The print control unit 13A supplies the print data Dp to the drive unit 49 and performs control processing (driving frequency fd, control processing of the conveying speed Vt, etc.). However, unlike the print control unit 13, the print control unit 13A acquires the unit time pulse number Np from the head control unit 48 as described above, and does not supply it to the drive unit 49 (unit time The number of pulses Np is not controlled) (see FIG. 9). In this modified example, the drive unit 49 acquires the unit time pulse number Np from the head control unit 48 as described above.

[B. Action/effect]
Even in such a modified example of the configuration, it is possible to obtain the same effect by basically the same action as the embodiment.

That is, in the printer 1A of this modification, as in the printer 1 of the embodiment, by controlling the unit time pulse number Np according to the dissolved oxygen amount DO in the ink 9, the ejection operation of the ink 9 ( printing operation) can be appropriately controlled according to the dissolved oxygen amount DO. As a result, in this modification, as in the embodiment, the printing operation can be continued without stopping within the range in which the generation of air bubbles in the ink 9 can be suppressed. It is possible to improve the performance.

Further, particularly in this modified example, the head controller 48 in the inkjet head 4A performs the above-described control (control of the unit time pulse number Np according to the dissolved oxygen amount DO, etc.). Become. That is, unlike the case of the embodiment (when the above-described control is performed in the print control unit 13 outside the inkjet head 4), such control can be performed within the inkjet head 4A. It is possible to simplify the configuration. In addition, since the number of pulses per unit time Np can be controlled by the head control unit 48, for example, even if the above-described thresholds (threshold Dth1 and threshold Dth2) are different between a plurality of types of products (products of the inkjet head 4A), Even if there is, it will be as follows. In other words, the user (the user of the inkjet head 4A) does not need to recognize the difference in the threshold value between the products of a plurality of types, and as a result, the user's convenience can be improved.

<3. Other modified examples>
Although the present disclosure has been described above with reference to the embodiments and modifications, the present disclosure is not limited to these embodiments and the like, and various modifications are possible.

For example, in the above-described embodiments and the like, specific configuration examples (shape, arrangement, material, number, etc.) of each member in the printer and the inkjet head have been described. It is not limited, and other shapes, arrangements, materials, numbers, and the like may be used. Also, the values, ranges, magnitude relationships, etc. of various parameters described in the above embodiments are not limited to those described in the above embodiments, and other values, ranges, magnitude relationships, etc. may be used. good.

Specifically, for example, in the above-described embodiments and the like, a single-row type (a type in which a plurality of nozzle holes Hn are arranged along a single line) ink jet head has been described as an example. is not limited. That is, for example, it may be a multi-row type inkjet head with two or more rows. Also, the shape of the nozzle hole Hn is not limited to the circular shape described in the above embodiments and the like, and may be, for example, a polygonal shape such as a triangular shape, an elliptical shape, a star shape, or the like. Furthermore, in the above-described embodiment and the like, the dissolved oxygen amount DO was described as an example of the "dissolved gas amount" in the present disclosure, but it is not limited to this example. That is, for example, depending on the dissolved amount of gas other than oxygen in the ink 9, the various control processes described in the above embodiments and the like may be performed.

Moreover, as the structure of the inkjet head, it is possible to apply each type. That is, for example, a so-called side-shoot type inkjet head that ejects the ink 9 from the central portion of the actuator plate in the extending direction of each ejection channel may be used. Alternatively, for example, a so-called edge shoot type inkjet head that ejects the ink 9 along the extending direction of each ejection channel may be used.

Further, the printer method is not limited to the methods described in the above embodiments and the like, and various methods such as the MEMS (Micro Electro Mechanical Systems) method can be applied.

In addition, in the above-described embodiments and the like, a non-circulating inkjet head that utilizes the ink 9 between the ink tank and the inkjet head without being circulated has been described as an example, but the present invention is not limited to this example. . That is, for example, the present disclosure can also be applied to a circulating inkjet head that circulates the ink 9 between the ink tank and the inkjet head.

In addition, in the above-described embodiments and the like, the control processing (control processing for unit time pulse number Np, drive frequency fd, transport speed Vt, etc.) during the printing operation according to the dissolved oxygen amount DO in the ink 9 is specifically described. Although an example was given and explained, the method is not limited to the method given in the above-described embodiment and the like. That is, another method may be used to perform control processing during the printing operation according to such dissolved oxygen amount DO (dissolved gas amount). Specifically, for example, in the above embodiment and the like, a method of controlling the driving frequency fd according to the dissolved oxygen amount DO was described as an example, but the method is not limited to this method, and may be used to (directly) control the number of pulses per unit time. Further, unlike the method described in the above embodiment and the like, for example, the movement speed (conveyance speed Vt) may not be controlled in accordance with the dissolved oxygen amount DO along with the control of the drive frequency fd. Furthermore, unlike the method described in the above embodiment, for example, in addition to (or instead of) the transport speed Vt in the transport mechanisms 2a and 2b, the scanning speed (of the inkjet head 4) in the scanning mechanism 6 is considered. may be used to control the movement speed. In addition, unlike the method described in the above embodiments and the like, for example, only one of the transport mechanisms 2a and 2b and the scanning mechanism 6 may constitute the moving mechanism. Further, unlike the method described in the above embodiments and the like, for example, the driving frequency fd may be controlled without checking the detection signal (conveyance speed detection signal Svt) of the conveyance speed Vt.

Also, the series of processes described in the above embodiments and the like may be performed by hardware (circuit) or by software (program). When it is performed by software, the software consists of a program group for executing each function by a computer. Each program, for example, may be installed in the computer in advance and used, or may be installed in the computer from a network or a recording medium and used.

Furthermore, in the above embodiments and the like, the printer 1 (inkjet printer) was described as a specific example of the "liquid jet recording apparatus" in the present disclosure, but the invention is not limited to this example, and other devices other than inkjet printers may be used. The present disclosure can also be applied to devices. In other words, the "liquid jet head" (inkjet head) of the present disclosure may be applied to devices other than inkjet printers. Specifically, for example, the "liquid jet head" of the present disclosure may be applied to devices such as facsimiles and on-demand printers.

Additionally, the various examples described so far may be applied in any combination.

Note that the effects described in this specification are merely examples and are not limited, and other effects may be provided.

In addition, the present disclosure can also be configured as follows.
(1)
A liquid jet recording apparatus that performs a printing operation on a recording medium,
a liquid jet head that jets liquid toward the recording medium based on a drive signal having one or more pulses;
a storage unit that stores the liquid;
a print control unit that controls the printing operation,
The print control unit
According to the amount of gas dissolved in the liquid supplied from the storage section toward the liquid jet head,
A liquid jet recording apparatus for controlling a unit time pulse number, which is the number of pulses per unit time included in the drive signal.
(2)
The print control unit
By controlling the driving frequency, which is the frequency of the driving signal during the printing operation for one pixel on the recording medium, according to the dissolved gas amount,
The liquid jet recording apparatus according to (1) above, wherein the number of pulses per unit time is controlled.
(3)
The print control unit
if the dissolved gas amount is less than a first threshold, maintaining the drive frequency unchanged from a specified value;
when the dissolved gas amount is equal to or greater than the first threshold value and less than the second threshold value, reducing the driving frequency from the specified value to a non-zero value (≠0);
The liquid jet recording apparatus according to (2), wherein the drive frequency is set to a zero value (=0) when the dissolved gas amount is equal to or greater than the second threshold value.
(4)
further comprising a moving mechanism for relatively moving the liquid jet head and the recording medium at a predetermined moving speed;
The liquid jet recording apparatus according to (2) or (3), wherein the print control section controls the moving speed of the moving mechanism according to the amount of dissolved gas in accordance with the control of the driving frequency.
(5)
The print control unit
if the dissolved gas amount is less than a first threshold, maintaining the moving speed unchanged from a specified value;
when the dissolved gas amount is equal to or greater than the first threshold value and less than the second threshold value, reducing the moving speed from the specified value to a non-zero value (≠0);
The liquid jet recording apparatus according to (4), wherein the moving speed is set to a zero value (=0) when the dissolved gas amount is equal to or greater than the second threshold value.
(6)
The moving mechanism includes a transport mechanism that transports the recording medium,
The liquid jet recording apparatus according to (4) or (5), wherein the moving speed is the transport speed of the recording medium in the transport mechanism.
(7)
The print control unit
Acquiring a detection signal of the transport speed in the transport mechanism,
The liquid jet recording apparatus according to (6), wherein the drive frequency is controlled while confirming the detection signal of the conveying speed.
(8)
a degassing device that performs a degassing process on the liquid when the liquid is supplied from the housing portion into the liquid jet head;
a measurement unit that measures the amount of dissolved gas in the liquid after the degassing process has been performed by the deaerator,
The liquid jet recording apparatus according to any one of (1) to (7), wherein the print control section controls the unit time pulse number according to the dissolved gas amount measured by the measurement section.
(9)
A liquid jet head for jetting a liquid,
an injection unit that injects the liquid toward a recording medium;
a drive unit configured to eject the liquid from the ejection unit based on a drive signal having one or more pulses;
a head control unit that controls the operation of the liquid jet head,
The head control unit
According to the amount of gas dissolved in the liquid supplied from the storage section that stores the liquid toward the liquid jet head,
A liquid jet head that controls a unit time pulse number, which is the number of pulses per unit time included in the drive signal.

Reference Signs List 1, 1A Printer 10 Housing 11 Deaerator 12 Dissolved oxygen measuring unit 13, 13A Print control unit 2a, 2b Conveying mechanism 21 Grid roller 22 Pinch roller 3 (3Y, 3M, 3C, 3K)... ink tank, 4 (4Y, 4M, 4C, 4K), 4A... inkjet head, 41... nozzle plate, 42... actuator plate, 43... cover plate, 48... head controller, 49 drive unit 50 ink supply tube 6 scanning mechanism 61a, 61b guide rail 62 carriage 63 drive mechanism 631a, 631b pulley 632 endless belt 633 drive motor 9 Ink P...recording paper d...transport direction Hn...nozzle hole Sd...drive signal Vd...drive voltage C1...channel C1e...ejection channel C1d...dummy channel (non-ejection channel) Wd...drive wall , Ed... drive electrode, Eda... individual electrode (active electrode), Edc... common electrode (common electrode), da... expansion direction, db... contraction direction, Dp... print data, Np... number of pulses per unit time, Td... drive cycle , fd... Drive frequency, Vt... Conveyance speed, fdH, VtH... Specified value, fdL, VtL... Non-zero value, Sc... Conveyance speed control signal, Svt... Conveyance speed detection signal, DO... Dissolved oxygen amount, Dth1, Dth2... Threshold, t...time.

Claims (7)

A liquid jet recording apparatus that performs a printing operation on a recording medium,
a liquid jet head that jets liquid toward the recording medium based on a drive signal having one or more pulses;
a storage unit that stores the liquid;
a printing control unit that controls the printing operation;
with
The print control unit
According to the amount of gas dissolved in the liquid supplied from the storage section toward the liquid jet head,By controlling the driving frequency, which is the frequency of the driving signal during the printing operation for one pixel on the recording medium,controlling the number of pulses per unit time included in the drive signal; when
if the dissolved gas amount is less than a first threshold, maintaining the drive frequency unchanged from a specified value;
when the dissolved gas amount is equal to or greater than the first threshold value and less than the second threshold value, reducing the driving frequency from the specified value to a non-zero value (≠0);
setting the drive frequency to a zero value (=0) when the dissolved gas amount is equal to or greater than the second threshold;
Liquid jet recording device. further comprising a moving mechanism for relatively moving the liquid jet head and the recording medium at a predetermined moving speed;
2. The liquid jet recording apparatus according to claim 1 , wherein the print control section controls the moving speed of the moving mechanism in accordance with the dissolved gas amount as the drive frequency is controlled. The print control unit
if the dissolved gas amount is less than a first threshold, maintaining the moving speed unchanged from a specified value;
when the dissolved gas amount is equal to or greater than the first threshold value and less than the second threshold value, reducing the moving speed from the specified value to a non-zero value (≠0);
3. The liquid jet recording apparatus according to claim 2 , wherein the moving speed is set to a zero value (=0) when the dissolved gas amount is equal to or greater than the second threshold value. A liquid jet recording apparatus that performs a printing operation on a recording medium,
a liquid jet head that jets liquid toward the recording medium based on a drive signal having one or more pulses;
a storage unit that stores the liquid;
a printing control unit that controls the printing operation;
a moving mechanism that relatively moves the liquid jet head and the recording medium at a predetermined moving speed;
with
The print control unit
Driving, which is the frequency of the driving signal during the printing operation for one pixel on the recording medium, according to the amount of gas dissolved in the liquid supplied from the housing section toward the liquid jet head. Controlling the number of pulses per unit time included in the drive signal by controlling the frequency, and
When controlling the moving speed in the moving mechanism according to the dissolved gas amount in accordance with the control of the driving frequency,
if the dissolved gas amount is less than a first threshold, maintaining the moving speed unchanged from a specified value;
when the dissolved gas amount is equal to or greater than the first threshold value and less than the second threshold value, reducing the moving speed from the specified value to a non-zero value (≠0);
If the dissolved gas amount is greater than or equal to the second threshold, set the moving speed to a zero value (=0)
Liquid jet recording device. The moving mechanism includes a transport mechanism that transports the recording medium,
5. The liquid jet recording apparatus according to claim 2 , wherein the moving speed is the transport speed of the recording medium in the transport mechanism. The print control unit
Acquiring a detection signal of the transport speed in the transport mechanism,
6. The liquid jet recording apparatus according to claim 5 , wherein the driving frequency is controlled while confirming the detection signal of the conveying speed. a degassing device that performs a degassing process on the liquid when the liquid is supplied from the housing portion into the liquid jet head;
a measurement unit that measures the amount of dissolved gas in the liquid after the degassing process has been performed by the deaerator,
7. The liquid jet recording apparatus according to any one of claims 1 to 6 , wherein the print control section controls the unit time pulse number according to the dissolved gas amount measured by the measurement section.

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