Manufacturing method for liquid discharge head

Abstract

To solve the problem that, when one head chip deteriorates, a liquid discharge head is entirely replaced and discarded, in the liquid discharge head configured so that a plurality of head chips is incorporated.SOLUTION: In the manufacturing method for a liquid discharge head, a first liquid discharge head, in which a first head chip is disposed at a first position in a plurality of arranged head chips and a second head chip that deteriorates more than the first head chip is disposed at a second position, is prepared, and the first head chip and the second head chip are detached from the first liquid discharge head. In a second liquid discharge head, in which use frequencies of the head chip disposed at a corresponding first position corresponding to the first position are lower than use frequencies of the head chip disposed at a corresponding second position corresponding to the second position, the second head chip is incorporated into the corresponding first position and the first head chip is incorporated into the corresponding second position.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a liquid ejection head and a method for managing head chips. [Background technology]

[0002] BACKGROUND ART A liquid ejection apparatus is known that includes a liquid ejection head that is equipped with a plurality of head chips that eject liquid such as ink (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-39804 Summary of the Invention [Problem to be solved by the invention]

[0004] In this conventional technology, when a liquid ejection head included in a liquid ejection device breaks down or reaches the end of its life due to deterioration through use, the liquid ejection head is replaced to repair the liquid ejection device. A single liquid ejection head is equipped with multiple head chips. Therefore, even though the deterioration and failure manifest themselves differently for each head chip, if some head chips are deemed unusable or near the end of their life, the entire liquid ejection head is replaced, resulting in the problem that even usable head chips or head chips with only minor deterioration are subject to disposal. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms or application examples: A manufacturing method of a liquid ejection head of the present disclosure includes a preparation step of preparing a first liquid ejection head in which a first head chip is arranged at a first position among a plurality of arranged head chips and a second head chip that is more deteriorated than the first head chip is arranged at a second position, a removal step of removing the first head chip and the second head chip from the first liquid ejection head, and a reassembly step of incorporating the second head chip into the corresponding first position and incorporating the first head chip into the corresponding second position in a second liquid ejection head in which the head chip that is arranged at a corresponding first position corresponding to the first position of the first liquid ejection head is used less frequently than the head chip that is arranged at a corresponding second position corresponding to the second position of the first liquid ejection head. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 2 is a top view showing a schematic configuration of a liquid ejection apparatus used in the method for manufacturing a liquid ejection head according to the first embodiment. [Figure 2] FIG. 1 is a side view showing a schematic configuration of a liquid ejection device. [Figure 3] FIG. 2 is an exploded perspective view showing the structure of a print head. [Figure 4] FIG. [Figure 5] FIG. 3 is a cross-sectional view of a head chip included in the head main body. [Figure 6] FIG. 2 is an explanatory diagram showing the functional configuration of the liquid ejection device. [Figure 7] FIG. [Figure 8] FIG. 3 is an explanatory diagram illustrating the configuration of a first liquid ejection head for which head chip recombination is performed in the first embodiment. [Figure 9] 3A to 3C are process diagrams showing the manufacturing process of the liquid ejection head according to the first embodiment. [Figure 10A] FIG. 4 is an explanatory diagram showing the connection between the relay board of the print head and the reading device. [Figure 10B] 5A and 5B are explanatory diagrams schematically showing the ejection performance of a head chip and the subsequent change over time. [Figure 11] 5A to 5C are explanatory views schematically showing the manufacturing process of the second liquid ejection head according to the first embodiment. [Figure 12] FIG. 10 is a schematic configuration diagram of a printer used in a manufacturing method according to a second embodiment. [Figure 13] FIG. 10 is an explanatory diagram illustrating the configuration of the ejection head and its surroundings of a printer used in a second embodiment. [Figure 14] FIG. 10 is an explanatory diagram illustrating the configuration of a liquid ejection head that is a target of a manufacturing method according to a second embodiment. [Figure 15] FIG. 10 is an explanatory diagram illustrating a manufacturing process according to a second embodiment. [Figure 16] FIG. 10 is an explanatory diagram schematically showing a liquid ejection head that is a target of a manufacturing method according to a third embodiment. [Figure 17] FIG. 10 is an explanatory diagram showing an example of a liquid ejection head used in a third embodiment. [Figure 18] FIG. 10 is an explanatory diagram illustrating the configuration of a liquid ejection head that is a target of a manufacturing method according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment of a method for manufacturing a liquid ejection head will be described with reference to the drawings. The drawings used are for convenience of explanation. The embodiments described below are merely examples of embodiments and do not limit the contents of the present disclosure. Furthermore, the configurations described below should not be construed as essential, except for those described as essential components.

[0008] A. First embodiment (A1) Overview of the liquid ejection device: A manufacturing method for a liquid ejection head according to the first embodiment will be described below. In the manufacturing method according to the first embodiment, a second liquid ejection head is manufactured by reusing some of the head chips included in one or more first liquid ejection heads. Here, the first liquid ejection head is a liquid ejection head that has been incorporated into a liquid ejection device or the like and used. The second liquid ejection head is a liquid ejection head manufactured by reusing at least some of the head chips included in the first liquid ejection head. Prior to describing the manufacturing method for the liquid ejection head, we will first describe the configuration of a head body corresponding to the first liquid ejection head, a print head incorporating the head body, and a liquid ejection device using the print head. In this specification, "ejection" refers to the act of sending liquid outward from a nozzle or the like. Ejection includes various modes of outputting a predetermined amount of liquid to the outside, such as spraying, spurting, spraying, discharging, and intermittent outflow, regardless of the type of liquid, output time, number of times, etc.

[0009] FIG. 1 is a top view showing the schematic configuration of a liquid ejection device 10. FIG. 2 is a side view showing the schematic configuration of the liquid ejection device 10. As shown in these figures, the liquid ejection device 10 used in this embodiment will be described as a so-called line-type inkjet printer, which performs printing simply by transporting a medium P onto which ink is ejected. Note that the liquid ejection device 10 is not limited to a line-type inkjet printer, and may also be a so-called serial-type inkjet printer, in which the print head moves in synchronization with the transport of the medium P.

[0010] In the following description, the transport direction in which the medium P is transported is referred to as direction X, with the upstream side of the transport of the medium P being the X1 side and the downstream side being the X2 side. Furthermore, in the in-plane direction of the landing surface where ink lands on the medium P, the direction perpendicular to direction X is referred to as direction Y, with one end of the liquid ejection device 10 in direction Y being the Y1 side and the other end being the Y2 side. Furthermore, the direction perpendicular to both directions X and Y, in which ink is ejected from the print head 3 onto the medium P, is referred to as direction Z, with the ink ejected from the print head 3 being ejected from the Z2 side toward the Z1 side of direction Z. In this embodiment, directions X, Y, and Z are described as being orthogonal axes, but the configuration of the liquid ejection device 10 is not limited to being arranged orthogonal to one another. These directions X, Y, and Z are also shown in other figures as appropriate.

[0011] 1 and 2, a liquid ejection device 10 includes a device main body 2, a print head 3, a storage unit 4, a medium transport mechanism 5, and a maintenance mechanism 6. First, these main components of the liquid ejection device 10 will be described.

[0012] The ink storage unit 4 stores ink to be supplied to the print head 3. This storage unit 4 is fixed to the device body 2. Examples of storage units 4 that store ink include ink cartridges, bag-shaped ink packs made of flexible film, and refillable ink tanks. The ink stored in the storage unit 4 is supplied to the print head 3 via a supply pipe 40 such as a tube. The storage unit 4 may store ink of multiple colors, such as black, cyan, magenta, yellow, red, and gray. Therefore, the storage unit 4 may include multiple ink cartridges, ink packs, and ink tanks corresponding to the ink colors to be stored, and the supply pipe 40 may include multiple tubes corresponding to the ink colors to be stored in the storage unit 4. The storage unit 4 may also be mounted on the print head 3.

[0013] A signal for controlling the ejection of ink is supplied to the print head 3 from the drive circuit board 7 via a cable 17. The print head 3 then ejects ink supplied from the ink reservoir 4 in an amount and at a timing according to the signal supplied from the drive circuit board 7. Details of the print head 3 will be described later.

[0014] The medium transport mechanism 5 is composed of a first transport unit 5a and a second transport unit 5b. The first transport unit 5a is located on the X1 side of the print head 3. At least a portion of the second transport unit 5b is located on the X2 side of the print head 3. The first transport unit 5a and the second transport unit 5b transport the medium P in the direction X from the X1 side to the X2 side.

[0015] The first transport unit 5a includes a transport roller 51a, a driven roller 52a, and a drive motor 53a. A driving force is supplied to the transport roller 51a from the drive motor 53a. The transport roller 51a is driven to rotate in accordance with the driving force supplied from the drive motor 53a. The transport roller 51a and the driven roller 52a sandwich the medium P and transport the medium P toward the X2 side. The driven roller 52a may include a spring (not shown) that presses the medium P toward the transport roller 51a by stress generated by a biasing member.

[0016] The second conveying section 5b includes a conveying roller 51b, a driven roller 52b, a drive motor 53b, a conveying belt 54b, a tension roller 55b, a biasing member 56b, and a pressure roller 57b.

[0017] The transport roller 51b is located on the X2 side of the print head 3 in the X direction. A driving force is supplied to the transport roller 51b from a drive motor 53b. The transport roller 51b is driven to rotate by the driving force supplied from the drive motor 53b. A driven roller 52b is provided at a position spaced a predetermined distance from the transport roller 51b on the X1 side, and an endless transport belt 54b is stretched between the driven roller 52b and the transport roller 51b. When the transport roller 51b is driven to rotate by the driving force supplied from the drive motor 53b, the transport belt 54b is driven by the transport roller 51b and transports the medium P fed by the driven roller 52a and the transport roller 51a downstream, i.e., toward the X2 side. The tension roller 55b is located between the transport roller 51b and the driven roller 52b and abuts against the inner surface of the transport belt 54b. The tension roller 55b applies tension to the transport belt 54b by the biasing force generated by a biasing member 56b, such as a spring.

[0018] The pressure rollers 57b are provided on the Z2 side of the medium P, on both the X1 side and the X2 side of the print head 3. The medium P is sandwiched between the pressure rollers 57b and the conveyor belt 54b, thereby maintaining a flat posture of the medium P. In order to maintain the position and posture of the medium P more precisely, a flat platen may be provided on the Z1 side of the conveyor belt 54b directly below the print head 3 (Z1 side).

[0019] In the liquid ejection device 10 configured as described above, the first transport unit 5a and the second transport unit 5b are driven to transport the medium P from the X1 side toward the X2 side in the direction X. Ink is ejected from the print head 3 at a predetermined timing onto the transported medium P. As a result, the ink ejected from the print head 3 lands at a desired position on the medium P, and a desired image is formed on the medium P.

[0020] The maintenance mechanism 6 performs maintenance functions to ensure that the print head 3 ejects ink normally. The maintenance mechanism 6 is used, for example, for wiping, flushing, cleaning, and capping. Wiping is a process in which a wiping member WP (see FIG. 5) provided in the maintenance mechanism 6 wipes the nozzle surface from which ink is ejected (hereinafter referred to as the nozzle surface) to remove ink, paper debris, and the like that has adhered to the nozzle surface. Flushing is a process in which a concave-shaped container (not shown) provided in the maintenance mechanism 6 is placed opposite the nozzle surface to eject ink from the nozzles, thereby driving a piezoelectric element 60 (described later) to eject ink from the nozzles, in order to maintain the viscosity of the ink stored inside the print head 3 within an appropriate range or, if an abnormality occurs in the viscosity of the ink stored inside the print head 3, to restore the viscosity to an appropriate state. The cleaning process may be, for example, suction cleaning, in which a capping space formed by covering the nozzle surface with a recessed cap (not shown) provided in the maintenance mechanism 6 is created by applying negative pressure using a negative pressure generating mechanism such as a pump (not shown) provided in the maintenance mechanism 6 connected to the cap, forcing ink out of the nozzles; or pressure cleaning, in which a flow path located upstream of a pressure generating chamber 631 (described below) is pressurized using a pressure generating mechanism such as a pump (not shown) provided in the maintenance mechanism 6, forcing ink out of the nozzles. In this embodiment, a line-type inkjet printer is used as the liquid ejection device 10, so the maintenance mechanism 6 is located in a different position from the print head 3. A print head moving mechanism (not shown) moves the print head 3 to the position of the maintenance mechanism 6, where the above-described wiping, flushing, cleaning, and other processes are performed. The number of times these processes are performed can be treated as one of the head chip characteristic information, as described below.

[0021] (A2) Printhead structure: Next, the structure of the print head 3 will be described. Figure 3 is a partially exploded perspective view showing the structure of the print head 3. As shown in the figure, the print head 3 has multiple head bodies 31, a base member 33, a flow path member 34, and a cover member 35. Figure 3 shows an example in which the print head 3 has six head bodies 31, but the number of head bodies 31 that the print head 3 has is not limited to this.

[0022] The head main body 31 has a plurality of head chips 310 and a holding member 360 that holds them. In this embodiment, the head main body 31 has six head chips 310, but the number of head chips 310 included in one head main body 31 may be more or less than six.

[0023] FIG. 4 shows an exploded perspective view of the detailed structure of a head main body 31 equipped with six head chips 310. The multiple head chips 31 equipped in the head main body 31 have the same structure within the range of manufacturing tolerance. FIG. 5 also shows the internal structure of the head chip 310. FIG. 5 is a cross-sectional view of the head chip 310 shown in FIG. 4, cut along the YZ plane at the center of its longitudinal direction. As shown in FIG. 5, each head chip 310 has a case 610, a protective substrate 620, a pressure chamber substrate 630, a flow path substrate 640, and a nozzle plate 650. In the head chip 310, the case 610, the protective substrate 620, the pressure chamber substrate 630, the flow path substrate 640, and the nozzle plate 650 are bonded together with an adhesive or the like. At least one of the multiple adhesives that bond these components together comes into contact with ink flowing through the flow paths in the head chip 310.

[0024] The structure of the head chip 310 will be described with reference to FIG. 5 . The nozzle plate 650 has a plurality of nozzles 651 that eject ink. Specifically, the nozzle plate 650 has a plurality of nozzle rows arranged along the direction Xa, which is the longitudinal direction of the head chip 310, and two rows arranged along the direction Ya. Here, the direction Xa is a direction inclined with respect to the direction X, which is the transport direction of the medium P, and the direction Ya is a direction that intersects with the direction Xa in the XY plane defined by the directions X and Y. That is, the head main body 31 is mounted on the print head 3 so that the arrangement direction of the nozzles 651 of the head chip 310 is inclined with respect to the direction X, which is the transport direction of the medium P. Note that the number of nozzle rows formed by the nozzles 651 is not limited to two, but may be one row or three or more rows. Here, the surface of the nozzle plate 650 on the Z1 side where the nozzles 651 open is referred to as the nozzle surface 652. The head chip 310 has one nozzle plate 650.

[0025] The pressure chamber substrate 630 is located on the Z2 side of the nozzle plate 650. The pressure chamber substrate 630 has a plurality of pressure generating chambers 631 partitioned by partitions or the like. Each pressure generating chamber 631 is located corresponding to a nozzle 651 of the nozzle plate 650. That is, the pressure chamber substrate 630 has the same number of pressure generating chambers 631 as the nozzles 651 provided in the nozzle plate 650. Furthermore, the plurality of pressure generating chambers 631 of the pressure chamber substrate 630 are arranged side by side in the direction Xa. The rows of the arranged pressure generating chambers 631 are arranged in two rows in the direction Ya.

[0026] The flow path substrate 640 is located on the Z2 side of the nozzle plate 650 and on the Z1 side of the pressure chamber substrate 630. In other words, the flow path substrate 640 is located between the nozzle plate 650 and the pressure chamber substrate 630 in the direction along the Z direction. The flow path substrate 640 has a common flow path 641, branch flow paths 642, communicating flow paths 643, and individual flow paths 644 for supplying ink supplied from the storage section 4 to each of the multiple nozzles 651.

[0027] The individual flow channels 644 communicate with the corresponding nozzles 651 and pressure generating chambers 631. The common flow channel 641 is provided in common to the multiple pressure generating chambers 631 included in the pressure chamber substrate 630 and the multiple nozzles 651 included in the nozzle plate 650. Ink is supplied to the common flow channel 641 from the reservoir 4. The ink supplied to the common flow channel 641 is supplied to the pressure generating chambers 631 via branch flow channels 642 and communicating flow channels 643 provided corresponding to the pressure generating chambers 631. In other words, the branch flow channels 642 and communicating flow channels 643 communicate the common flow channel 641 with the corresponding pressure generating chambers 631. In the flow channel substrate 640 configured as described above, the ink supplied to the common flow channel 641 branches at the branch flow channels 642 so as to correspond to each of the multiple pressure generating chambers 631, and then supplies the ink to the pressure generating chambers 631 via the communicating flow channels 643.

[0028] A vibration plate 621 is bonded to the Z2-side surface of the pressure chamber substrate 630. Furthermore, a plurality of piezoelectric elements 60 corresponding to the plurality of pressure generating chambers 631 are provided on the Z2-side surface of the vibration plate 621. Specifically, each piezoelectric element 60 includes electrodes 602, 603 and a piezoelectric layer 601. The electrode 602, the piezoelectric layer 601, and the electrode 603 are laminated in this order on the Z2-side surface of the vibration plate 621, facing from the Z1 side to the Z2 side in the direction Z. One of the electrodes 602, 603 of each piezoelectric element 60 is configured as a common electrode that supplies a signal of a common voltage value to the piezoelectric element 60, and the other of the electrodes 602, 603 is configured as an individual electrode that supplies a signal of an individual voltage value to each piezoelectric element 60. While this embodiment will be described assuming that the electrode 602 is an individual electrode and the electrode 603 is a common electrode, this is not a limitation. A drive signal COM is supplied to the electrode 602, which is an individual electrode, and a reference voltage signal indicating the reference potential Vbs of the drive signal COM is supplied to the electrode 603, which is a common electrode.

[0029] In the piezoelectric element 60 configured as described above, the piezoelectric layer 601 deforms in response to a potential difference generated between the electrode 602 and the electrode 603. That is, the piezoelectric element 60 is driven in response to a potential difference between the voltage value of a signal supplied to the electrode 602 and the voltage value of a signal supplied to the electrode 603. When the piezoelectric element 60 is driven, the vibration plate 621 is displaced. When the vibration plate 621 is displaced toward the Z2 side, the internal pressure of the pressure generating chamber 631 decreases. As a result, ink is supplied to the pressure generating chamber 631 from the common flow path 641 via the branch flow path 642 and the communication flow path 643. On the other hand, when the vibration plate 621 is displaced toward the Z1 side, the internal pressure of the pressure generating chamber 631 increases. As a result, ink stored in the pressure generating chamber 631 is ejected from the nozzle 651 via the individual flow path 644. Here, a configuration including the piezoelectric element 60, the pressure generating chamber 631, the individual flow path 644, and the nozzle 651 is referred to as an ejection unit 600 that ejects ink from the head chip 310.

[0030] The protective substrate 620 is located on the Z2 side of the diaphragm 621. The protective substrate 620 has a holding portion 622 that forms a space for protecting the piezoelectric element 60. The space formed by the holding portion 622 has a size sufficient to accommodate displacement caused by driving the piezoelectric element 60.

[0031] The case 610 is located on the Z2 side of the flow path substrate 640 and the protective substrate 620. The case 610 has a manifold 611 that communicates with a common flow path 641 of the flow path substrate 640. The manifold 611 is a space that stores ink to be supplied to the plurality of nozzles 651, and is provided continuously over the plurality of nozzles 651 and the plurality of pressure generating chambers 631. The ink supplied to this manifold 611 is supplied to the common flow path 641. In other words, the common flow path 641 and the manifold 611 are a common liquid chamber that communicates with the plurality of nozzles 651. The common liquid chamber extends with its longitudinal direction being the direction Xa in which the plurality of nozzles 651 are arranged.

[0032] Furthermore, in the head main body 31, the protective substrate 620 and the case 610 are provided with through-holes 313 that penetrate in the direction Z. A flexible wiring substrate 311 is inserted into the through-hole 313. One end of the flexible wiring substrate 311 is electrically connected to lead electrodes drawn from the electrodes 602 and 603 of the piezoelectric element 60. That is, a signal for driving the piezoelectric element 60 is transmitted to the flexible wiring substrate 311. An integrated circuit 312 is mounted on the flexible wiring substrate 311. The signal for driving the piezoelectric element 60, which is transmitted through the flexible wiring substrate 311, is input to the integrated circuit 312. The integrated circuit 312 controls the timing at which the signal for driving the piezoelectric element 60 is supplied to the electrode 602 based on the input signal. This controls the timing at which the piezoelectric element 60 is driven and the amount of drive of the piezoelectric element 60. Therefore, a predetermined amount of ink is ejected at a predetermined timing from the ejection unit 600 including the piezoelectric element 60. A water-repellent film 658 is formed on the outer surface of the nozzle plate 650, and when the surface of the head chip 310 becomes dirty, the nozzle plate 650 is wiped by a wiping member WP.

[0033] Pressure fluctuations for ejecting ink from the nozzles 651 are generated in the head chip 310 by a piezoelectric element 60 including an electrode 603, a piezoelectric layer 601, and an electrode 602, one pressure generating chamber 631, and a vibration plate 621. The piezoelectric element 60, pressure generating chamber 631, and vibration plate 621 are collectively referred to as a segment. The head chip 310 has as many such segments as there are nozzles 651. The segments have various characteristics related to the ejection of liquid, such as the natural frequency of the segment, the weight of the ink droplets ejected from the nozzles 651, the speed of the ink droplets ejected from the nozzles 651, and the displacement of the vibration plate 621 of the segment.

[0034] The natural frequency of a segment can be measured using known devices and methods. For example, a known measuring instrument called an impedance analyzer is used to input a specific sine wave into the segment and measure its impedance. The impedance of the segment changes by changing the frequency of the input sine wave. The frequency of the input sine wave at which the impedance peaks can be measured as the natural frequency of the segment. This natural frequency is a value correlated to the natural vibration period Tc of the liquid in the pressure generating chamber 631.

[0035] The weight of the ink droplets ejected from the nozzle 651 can be measured using known devices and methods. For example, a drive signal COM including a specific drive waveform (reference drive waveform) that enables droplets to be ejected is applied to the piezoelectric element 60, causing it to eject a certain number of droplets into a receiving container. Then, the weight of the ink droplets ejected from the nozzle 651 can be measured by measuring the weight change of the receiving container and the weight change of the reservoir 4, which is the ink supply source. A high-precision weighing scale such as an electronic balance can be used for this measurement.

[0036] The displacement of the diaphragm 621 of the segment is the difference between the maximum and minimum displacements of the vibrating part where piezoelectric distortion is generated by the piezoelectric element 60. The displacement of the diaphragm 621 of the segment is also simply called the displacement of the segment. The displacement of the segment can be measured using known devices and methods. For example, a Doppler vibrometer utilizing the difference in wavelength that occurs in the round trip path of an irradiated laser when reflected by the vibrating diaphragm 621 can be used to measure the speed at which the diaphragm 621 is moving due to vibration, and the displacement of the diaphragm 621 can be measured by integrating this speed.

[0037] The natural frequency of these segments, the weight of ink droplets ejected from nozzle 651, the speed of ink droplets ejected from nozzle 651, the displacement of diaphragm 621, and the like can be used to rank the head chips, which will be described later. Note that the aforementioned measured values ​​such as the natural frequency may differ between multiple segments included in one head chip 310. In such cases, the ranking may be performed using the average value or mode of the measured values ​​of multiple segments included in one head chip.

[0038] The head chips 310 configured as described above are held by a holding member 360 in the head main body 31. As shown in Fig. 4, the holding member 360 includes a flow path member 361 common to the multiple head chips 310, a holder 362 that holds the multiple head chips 310, and a first relay substrate 363 that is electrically connected to at least two or more head chips 310. The first relay substrate 363 of this embodiment is electrically connected to all of the head chips 310 that the head main body 31 includes.

[0039] A flow path is provided inside the flow path member 361 for supplying ink supplied from the reservoir 4 via the flow path member 34 to each head chip 310. This flow path is connected to an ink supply unit 364 provided on the Z2 side surface of the flow path member 361. That is, ink supplied from the reservoir 4 is supplied to the flow path member 361 via the ink supply unit 364. Note that the flow paths provided inside the flow path member 361 are provided corresponding to each ink supply unit 364. Here, although FIG. 4 shows the flow path member 361 having four ink supply units 364, this is not limited to this. A filter may be provided inside the flow path member 361 for removing foreign matter such as dust and air bubbles contained in the supplied ink.

[0040] At both ends of the flow path member 361 in the direction X, cable insertion holes 365 are provided that penetrate in the direction Z. A cable 366 electrically connected to a first relay board 363 (described later) via a connector 368 is inserted into the cable insertion hole 365. Here, the connector 368 is detachably connected to the cable 366, and is electrically connected to a plurality of terminals corresponding to a plurality of wires included in the cable 366.

[0041] The holder 362 is located on the Z1 side of the flow path member 361, and is fixed to the flow path member 361 by screws 381 shown in FIG. 3. The holder 362 also has a holding portion 367. The holding portion 367 is a groove-shaped space that is continuous in the direction Y on the Z1 side surface of the holder 362 and is open to both side surfaces in the direction Y. A plurality of head chips 310 are bonded to the holding portion 367 by an adhesive or the like (not shown). In this way, the plurality of head chips 310 are held by the holding member 360.

[0042] Furthermore, a flow path (not shown) that communicates with a flow path provided inside flow path member 361 is provided inside holder 362. Ink supplied from ink supply unit 364 is supplied to each head chip 310 via a flow path provided inside flow path member 361 and a flow path provided inside holder 362. In other words, holder 362 is a flow path member common to multiple head chips 310.

[0043] The first relay substrate 363 is located between the flow path member 361 and the holder 362. The flexible wiring substrates 311 of the head chips 310 are electrically connected to the first relay substrate 363. The first relay substrate 363 is also provided with a connector 368. The first relay substrate 363 configured as described above transmits signals input via cables 366 electrically connected to the connectors 368 to the corresponding head chips 310, and outputs signals output from the head chips 310 via the flexible wiring substrates 311 to the outside of the head main body 31 via the connectors 368 and the cables 366. The first relay substrate 363 is also provided with a memory 201.

[0044] The head main body 31 described above includes a cover 32 that covers the multiple head chips 310 between it and the holder 362. In other words, the multiple head chips 310 are arranged inside the storage space S, which is a space defined by the holding portion 367 of the holder 362 and the cover 32. This reduces the risk that ink droplets floating inside the liquid ejection device 10 will adhere to each head chip 310. In other words, the cover 32 protects the head chips 310 of the head main body 31 from ink droplets.

[0045] The cover 32 is provided on the Z1 side, which is the nozzle surface 652 side, of the multiple head chips 310 provided on the head main body 31. As shown in FIG. 4, the cover 32 includes a base portion 321 and extension portions 322 and 323. The base portion 321 is a plate-like member provided on the nozzle surface 652 side of the head chip 310 covered by the cover 32. The cover 32, together with the base portion 321, forms a space with the extension portions 322 and 323, and the holder 362 is inserted into the formed space. The base portion 321 is joined to the Z1 side surface of the holder 362 with an adhesive or the like (not shown).

[0046] Base portion 321 has a plurality of openings 324. Each opening 324 corresponds to a respective head chip 310, and exposes a plurality of nozzles 651 of the corresponding head chip 310 to the outside. This allows ink ejected from each head chip 310 to land on medium P without being obstructed by cover 32.

[0047] Returning to FIG. 3 , a plurality of head bodies 31 are fixed to the base member 33. The base member 33 includes an accommodation portion 332 having a space therein that opens to the Z1 side. The plurality of head bodies 31 are accommodated and held in this space. Specifically, the head bodies 31 are accommodated in the accommodation portion 332 of the base member 33 so that the nozzle surface 652 side of the head body 31 protrudes further toward the Z1 side than the accommodation portion 332. In this case, each of the plurality of head bodies 31 is accommodated in the accommodation portion 332 so that the nozzle row located on the nozzle surface 652 is oriented along the direction Xa that is inclined with respect to the direction X.

[0048] When the head main body 31 is housed in the base member 33, the head main body 31 is fixed to the base member 33 via a spacer 37. The spacer 37 is fixed to the Z2-side surface of the head main body 31 by a screw 382, ​​and is also fixed to the Z1-side surface of the base member 33 by a screw 383. That is, the head main body 31 is fixed to the base member 33 via the spacer 37. As described above, by fixing the spacer 37 fixed to the head main body 31 by the screw 382 to the base member 33 by the screw 383, it becomes possible to easily attach and detach the head main body 31 to and from the base member 33. Note that the method of fixing the spacer 37 and the head main body 31 is not limited to using the screw 382.

[0049] The base member 33 also has a supply hole 331 that penetrates in the direction Z. An ink supply unit 364 of the head main body 31 fixed to the base member 33 is inserted into the supply hole 331. The base member 33 also has an opening 333 that penetrates in the direction Z. A cable 366 of the print head 3 fixed to the base member 33 is inserted into the opening 333.

[0050] Furthermore, steps 334 that open to the Z2 side are provided on the outer periphery of both sides of the housing portion 332 that face each other in the direction X. A second relay board 335 is housed in each of the steps 334. Cables 366 that correspond to each of the multiple head bodies 31 and that are led out from the multiple openings 333 are electrically connected to the second relay board 335. As a result, the second relay board 335 propagates signals that are input to each of the multiple head bodies 31 and signals that are output from the multiple head bodies 31.

[0051] An integrated circuit 336 is mounted on the second relay board 335. Although the print head 3 shown in Figure 3 includes two second relay boards 335, each equipped with an integrated circuit 336, the integrated circuit 336 may be provided on only one of the two second relay boards 335, or the print head 3 may include only one second relay board 335. The two second relay boards 335 are fixed to the accommodation section 332 with screws 384.

[0052] A cable 17 is connected to the second relay board 335, which is electrically connected to the drive circuit board 7 fixed to the device body 2. This allows various signals generated by the drive circuit board 7 to be input to the print head 3. The electrical wiring of each head chip 310, the integrated circuit 312, the first relay board 363, the second relay board 335, etc. will be described later.

[0053] The flow path member 34 is provided on the Z2 side of the base member 33. The flow path member 34 is a flow path member common to the multiple head bodies 31, and distributes and supplies ink supplied from the storage section 4 to each of the multiple head bodies 31. A flow path (not shown) is provided inside the flow path member 34 for supplying the ink supplied from the storage section 4 to the multiple head bodies 31. The flow path provided inside this flow path member 34 communicates with a supply pipe 40 connected to the storage section 4, and also communicates with an ink supply section 364 of the head body 31. As a result, the ink supplied from the storage section 4 is supplied to the corresponding head body 31.

[0054] The cover member 35 is provided on the Z2 side of the flow path member 34. The cover member 35 is a box-shaped member that covers the flow path member 34 and the second relay board 335. The cover member 35 is provided with an opening 351 for inserting the cable 17 and an opening 352 for inserting the supply pipe 40. The cover member 35 is fixed to the housing portion 332 of the base member 33 with screws 385.

[0055] As described above, the print head 3 is a print head 3 that is assembled into a liquid ejection device 10 that ejects ink onto a medium P, and the print head 3 has multiple head bodies 31, and each head body 31 has multiple head chips 310.

[0056] (A3) Functional configuration of the liquid ejection device: Next, the functional configuration of the liquid ejection device 10 will be described. Fig. 6 is a diagram showing the functional configuration of the liquid ejection device 10. As shown in Fig. 6, the liquid ejection device 10 has a print head 3, a medium transport mechanism 5, a maintenance mechanism 6, a drive circuit board 7, a main circuit board 8, and an information output mechanism 9. The configuration of the medium transport mechanism 5 has already been explained, so below, the print head 3, the maintenance mechanism 6, the drive circuit board 7, and the main circuit board 8 will be briefly explained in order.

[0057] The hardware configuration of the print head 3 has already been described in detail. The internal electrical configuration of the print head 3 will be described with reference to FIG. 6. As shown in the figure, the print head 3 has n head bodies 31, each of which has m head chips 310. That is, the print head 3 will be described as having a total of n × m head chips 310, where n and m are both integers greater than or equal to 2. In the head body 31, each head chip 310 is connected to a first relay substrate 363 via m flexible wiring substrates 311. The connection between the first relay substrate 363 and each head chip 310 is achieved by connecting a connector 315 provided on the other end of the flexible wiring substrate 311 to a connector 314 of the first relay substrate 363. The connectors 315 and 314 are detachably connected.

[0058] In the following description, when distinguishing between n head bodies 31, they may be written as head bodies 31-1 to 31-n, and similarly when distinguishing between m head chips 310 or flexible wiring boards 311, they may be written as head chips 310-1 to 310-m or flexible wiring boards 311-1 to 311-m. When it is not necessary to distinguish between head bodies 31-1 to 31-n, flexible wiring boards 311-1 to 311-m, or head chips 310-1 to 310-m, they will simply be called head body 31, flexible wiring board 311, and head chip 310.

[0059] An integrated circuit 312 is provided on each flexible wiring board 311. This integrated circuit 312 includes a memory 200 and a drive signal selection control circuit 210. The memory 200 stores data such as the usage history of the head chip 310 that includes the memory 200. The drive signal selection control circuit 210 also selects signals to be sent to the multiple piezoelectric elements 60 provided in the head chip 310, and ejects liquid, in this case ink, from a desired nozzle 651 out of the multiple nozzles 651 provided in the head chip 310.

[0060] The configuration of this drive signal selection control circuit 210 is shown schematically in Figure 8. As shown in the figure, the head chip 310 is provided with piezoelectric elements 60 that generate pressure changes for ejection, corresponding to each of the multiple nozzles 651. When this piezoelectric element 60 receives a drive signal COM via the drive signal selection control circuit 210, it expands and contracts along the Z direction in accordance with the applied voltage. The drive signal COM and reference voltage signal are shown in Figure 7.

[0061] The drive signal selection control circuit 210 includes a plurality of switching elements provided corresponding to the plurality of piezoelectric elements 60. The switching elements select whether or not to supply a drive signal COM to the individual electrode of the corresponding piezoelectric element 60 for each printing cycle TP based on a clock signal, a latch signal, a change signal, a print data signal, and the like (not shown).

[0062] As shown in FIG. 7, the drive signal COM is, for example, a trapezoidal wave, and has a period in which it maintains the minimum potential VL and a period in which it maintains the maximum potential V H The duration of the voltage, the minimum potential VL, and the maximum potential V H The intermediate potential V C The reference voltage signal is a signal in which a constant reference potential Vbs smaller than the minimum potential VL continues. While power is being supplied to the head main body 31, the intermediate potential V of the drive signal COM is always C is applied to the individual electrodes of the piezoelectric elements 60 during the period when liquid is not being ejected from the nozzles 651, and the reference potential Vbs of the reference voltage signal is applied to the common electrode. Cand the reference voltage signal Vbs, affects the amount of deformation of the piezoelectric element 60 and changes over time in the deformation characteristics. Therefore, the magnitude of this reference voltage Vm may be treated as one piece of characteristic information of the head chip 310. Another item that can be treated as characteristic information is the environmental temperature of the head chip 310. The environmental temperature of the head chip 310 can be detected by providing a temperature sensor in the integrated circuit 312 or the like, but the temperature inside the housing of the liquid ejection device 10 or the temperature around the head chip 310 may also be treated as the environmental temperature. A method of storing the reference voltage Vm and the environmental temperature in the memory 200 of the head chip 310 and treating them as characteristic information will be described later.

[0063] Signals from the head chip 310 and drive signals COM to the head chip 310 are collected on a first relay board 363. The n first relay boards 363 are connected to a second relay board 335 by cables 366. The cables 366 are connected to connectors 368 provided on the first relay board 363 and connectors 337 provided on the second relay board 335, electrically connecting the two boards. An integrated circuit 336 is provided on the second relay board 335. The integrated circuit 336 includes a memory 203 and n selectors 202. The n selectors 202 are provided corresponding to the head bodies 31-1 to 31-n, respectively. The selectors 202 receive print data signals, memory control signals, latch signals, and change signals input from the drive circuit board 7. Then, depending on the logical levels of the input latch signal and change signal, the selector 202 selects whether to output the print data signal, latch signal, and change signal to the head main body 31, or whether to output the memory control signal, latch signal, and change signal to the memory 200 of the flexible wiring board 311.

[0064] The print head 3 described above is electrically connected to the drive circuit board 7 via the second relay board 335. The second relay board 335 and the drive circuit board 7 are connected via a cable 17. One end of the cable 17 is connected to a connector 27b provided on the second relay board 335, and the other end is connected to a connector 27a provided on the drive circuit board 7, thereby mediating the exchange of signals between them.

[0065] The drive circuit board 7 includes a control circuit 71, a drive signal output circuit 72, and a drive state detection circuit 73. The control circuit 71 outputs a memory control signal for controlling the memory 203 of the second relay board 335. Here, control of the memory 203 includes a read process for reading out information stored in the memory 203 and a write process for writing information to the memory 203. The control circuit 71 also generates a drive data signal that defines the voltage waveform of the drive signal COM for driving the piezoelectric element 60, and outputs the signal to the drive signal output circuit 72. The drive signal output circuit 72 amplifies the voltage waveform defined by each of the drive data signals.

[0066] The drive status detection circuit 73 generates a discharge section status signal indicating the status of the corresponding discharge section 600 based on the residual vibration signal input from the head chip 310 via the first relay board 363 and the second relay board 335. The drive status detection circuit 73 outputs this discharge section status signal to the control circuit 71. Based on the input discharge section status signal, the control circuit 71 determines whether or not to cause the maintenance mechanism 6 to perform a wiping process, a flushing process, a cleaning process, etc., generates an operation information signal indicating the determination result, and outputs the signal to the liquid discharger control circuit 81 via the cable 18, etc.

[0067] The main circuit board 8 has a liquid ejection device control circuit 81, a signal conversion circuit 82, a time measurement circuit 83, a power supply circuit 84, and a voltage detection circuit 85. The main circuit board 8 is provided with connectors 25a, 26a, 28a, and 29a. The main circuit board 8 is connected to the drive circuit board 7 via a cable 18 connected to the connector 28a, to the medium conveyance mechanism 5 via a cable 15 connected to the connector 25a, to the maintenance mechanism 6 via a cable 16 connected to the connector 26a, and to the information output mechanism 9 via a cable 19 connected to the connector 29a. Connectors 28b, 25b, 26b, and 29b, to which the other ends of the cables 18, 15, 16, and 19 are connected, are provided on each of the destination boards and mechanisms. The connectors used in this specification are not limited to specific types as long as they are configured to electrically and detachably connect wiring members without using bonding such as conductive adhesive or soldering. Here, the aforementioned connectors 314 and 315 are each a convex connector and a concave connector, and are detachably electrically connected by inserting and removing the convex connector into the concave connector. In this way, a configuration may be used in which connectors other than connectors 314 and 315 are connected to connectors other than the connectors in question.

[0068] The liquid ejection device control circuit 81 exchanges signals with each component of the liquid ejection device 10 to control the operation of each component. For example, it exchanges instructions for transporting the medium P and transport information for the transported medium P with the medium transport mechanism 5. The liquid ejection device control circuit 81 also exchanges control signals for controlling the operation of the maintenance mechanism 6 with the maintenance mechanism 6. Similarly, the liquid ejection device control circuit 81 exchanges control signals for controlling the operation of the information output mechanism 9 with the information output mechanism 9. Furthermore, the liquid ejection device control circuit 81 inputs image data signals from an external device, such as a host computer, external to the liquid ejection device 10, performs necessary processing on the image data signals, and outputs the processed image data to the signal conversion circuit 82. The signal conversion circuit 82 converts the input image data signals into image signals corresponding to the ink colors used in the liquid ejection device 10 and outputs the converted image data to the drive circuit board 7.

[0069] An external commercial power supply is input to the power supply circuit 84. The power supply circuit 84 converts the input commercial power into, for example, a 42V DC voltage and outputs it. The DC voltage output from the power supply circuit 84 is input to a voltage detection circuit 85 and is also used as a power supply voltage for each component of the liquid ejection device 10. The voltage detection circuit 85 detects whether power is being supplied to the liquid ejection device 10 based on the voltage value of the DC voltage. The voltage detection circuit 85 generates a voltage detection signal of a logic level corresponding to the detection result and outputs it to the time measurement circuit 83. For example, if the voltage value of the DC voltage deviates from a predetermined range, the voltage detection circuit 85 outputs an L-level voltage detection signal to the time measurement circuit 83. If the voltage value of the DC voltage is within the predetermined range, the voltage detection circuit 85 outputs an H-level voltage detection signal VDET to the time measurement circuit 83. The time measurement circuit 83 determines whether power is being supplied to the liquid ejection device 10 based on the voltage detection signal. Then, when the time measurement circuit 83 determines based on the voltage detection signal that power supply voltage is being supplied to the liquid ejection device 10, it generates elapsed time information and outputs it to the liquid ejection device control circuit 81. This elapsed time information is used to count the usage time of the liquid ejection device 10, and in turn, the head chip 310, etc.

[0070] The information output mechanism 9 outputs various types of information to the user of the liquid ejection device 10. The liquid ejection device control circuit 81 generates a control signal for controlling the operation of the information output mechanism 9 and outputs the control signal to the information output mechanism 9 via a cable 19 connected to a connector 29a. The information output mechanism 9 includes, for example, a display. The display displays various types of information such as information indicating the operating status of the liquid ejection device 10, information indicating the operating status of the maintenance mechanism 6, information regarding the usage history of the print head 3, and warning information. The information output mechanism 9 may be configured to notify the user of various types of information, and may include a configuration for notifying the user of information by voice, light, or the like, for example.

[0071] (A4) Head chip manufacturing: As explained above, the print head 3 incorporated into the liquid ejection device 10 is provided with a plurality of head bodies 31, and each head body 31 further incorporates a plurality of head chips 310. Six head bodies 31-1 to 31-6 are combined to form the print head 3. This print head 3 will be referred to below as the first liquid ejection head 3. The first liquid ejection head 3 after the head chips 310 have been rearranged will be referred to as the second liquid ejection head 3x. Other terminology will be defined as follows: First position: The position where the head tip that is expected to be used relatively more frequently is placed, comparing the frequency of use of the head tip. Second position: A position where a head tip that is expected to be used relatively less frequently is placed, comparing the frequency of use of the head tip. Head chip characteristic information: Information relating to the liquid ejection capability of the head chip 310 provided in the first liquid ejection head 3. This is expressed by the usage history of the head chip or the measurement results of measuring the head chip 310 itself. Initial characteristic value: Information relating to the ejection capacity immediately after manufacturing the head chip 310. Expressed as the ejection amount according to the reference drive signal or information specifying the category to which this ejection amount belongs.

[0072] The configuration of the liquid ejection head 3 used in the manufacturing method of the liquid ejection head of the first embodiment will be described with reference to FIG. 8. In the figure, the print head 3 is shown as a first liquid ejection head 3a in order to distinguish between the liquid ejection head 3 before and after the head chip rearrangement process. As shown in the figure, the first liquid ejection head 3a has the above-mentioned head bodies 31-1 to 31-6 arranged along the Y direction, which is the width direction of the printing medium P. For convenience of illustration, the head body 31-3 is not shown. Each head body 31 has six head chips 310. In the figure, suffixes a to w are added to the head chips, such as 310a to 310c, 310h, 310i, 310u to 310w, and when explaining differences in arrangement in the Y direction, they will be referred to as head chip 310a.

[0073] As shown in the figure, the head chips 310 included in each of the head bodies 31-1 to 31-6 are arranged at an angle with respect to the X direction, which is the transport direction of the printing medium P. Therefore, when viewed in the X direction, adjacent head chips 310, for example, the +X direction half of head chip 310h and the -X direction half of head chip 310i, are located at a position where they overlap. Furthermore, head chip 511, located at the end in the +Y direction, is not used to eject liquid due to its tilted direction. On the other hand, head chip 310w, located at the end in the -Y direction, only uses half of the nozzles Nz. Therefore, the range into which liquid is ejected, i.e., the printing range for the printing medium P, is the printing area PA shown in the figure. Area OP shown in the figure indicates outside the printing area.

[0074] As will be described in a second embodiment later, this printer 100 is provided with a position guide 678. Since the print medium P is transported through the center of the width direction (Y direction) of the first liquid ejection head 3a regardless of its width, the area including the width direction center of the first liquid ejection head 3a is referred to as the high-frequency area PM, where the head chips 310 are frequently used, and the areas on both sides of the high-frequency area PM are referred to as low-frequency areas PS. In the illustrated example, the low-frequency area PS in the +Y direction includes the head chips 512 and 513 of the head main body 31-1, and the low-frequency area PS in the -Y direction includes the head chips 310u and 310v of the head main body 31-6. In this first liquid ejection head 3a, the central area, such as the head chips 310h and 310i of the head main body 31-4 at the center in the Y direction, is likely to be second head chips that are frequently used and have a high degree of deterioration, and the positions of these head chips are likely to be in the second position. On the other hand, in the first liquid ejection head 3a, the head chips 310a and 310w at both ends in the Y direction, and the head chips 310b and 310c and head chips 310u and 310v provided on the head bodies 31-1 and 31-6 at both ends are likely to be first head chips that are used less frequently and have a lower degree of deterioration, and the positions of these head chips are likely to be the first positions.

[0075] Next, a method for manufacturing a liquid ejection head will be described with reference to the process diagram in FIG. 9. Here, as shown in FIG. 8, the process begins with the first liquid ejection head 3a, and ultimately, as will be described later, the second liquid ejection head 3x shown in FIG. 11 is manufactured. Since both heads basically have the same configuration with the same head chip 310 rearranged, this case can be considered as manufacturing by repair. Manufacturing begins with a process for preparing the first liquid ejection head 3a (step S101). In this case, the first liquid ejection head 3a is prepared in a state removed from the printer 100.

[0076] The following processes are performed: a reading device connection process (step S111) that connects the reading device 65 to the first liquid ejection head 3a that has been removed from the printer 100; a reading process (step S121) that reads data related to the status such as the number of ejections; a head chip selection process (step S131); and a removal process (step S141) that removes the head chip.

[0077] 10A, the connection of the reading device 65 in the reading device connection process (step S111) is performed by connecting the connection cable 63 of the reading device 65 to the connector 27b of the second relay board 335 of the print head 3a. At this time, the originally connected cable 17 may be used instead of the connection cable 63. Alternatively, the connection cable 63 of the reading device 65 may be connected to the connector 368 of the first relay board 363 of each head main body 31.

[0078] When the reading device 65 is connected to the first relay board 363, the characteristic information of all of the head chips 310-1 to 310-6 provided in one head main body 31-1, etc. can be read out sequentially from the memory 200 corresponding to each head chip 310. When the reading device 65 is connected to the second relay board 335, the characteristic information of each of the head chips 310 provided in all of the head main bodies 31-1 to 31-6 connected to the second relay board 335 can be read out sequentially from the corresponding memory 200. Note that the signals and power required to read data such as the characteristic information from the memory 200 are output from the reading device 65 to the second relay board 335 and the first relay board 363 via the connection cable 63.

[0079] The subsequent data reading process (step S121) is a process in which the reading device 65 reads data indicating the state of each head chip 310, such as the cumulative number of ejections and initial characteristic values. Since this data is recorded in memory 200 provided for each head chip 310 of the first liquid ejection head 3a, it is convenient to connect the reading device 65 and read the data before removing each head chip 310. The read data is saved in a recording device such as a hard disk inside the reading device 65. The data may be saved in a storage device provided within the reading device 65, or in a storage device provided in the cloud.

[0080] An example of the read data on the ejection characteristics is shown in Figure 10B. As shown, the manufactured head chips 310 undergo measurement of their ejection performance, including initial characteristic values, and are then classified and ranked according to the measured initial characteristic values ​​before being assembled. In this embodiment, the initial characteristic values ​​refer to the ejection characteristics obtained when a standard drive signal COM is applied to the manufactured head chip 310. Figure 10B schematically illustrates how the ejection volume of a head chip 310 with a predetermined initial characteristic value changes with subsequent use. In the figure, the vertical axis represents the ejection volume obtained when a drive signal COM with a standard center voltage Vm is applied, and the horizontal axis represents the change in ejection volume depending on the number of subsequent ejections. The figure examines long-term changes in characteristics by maintaining a constant number of ejections per unit time; the number of ejections and the elapsed time are approximately the same. The elapsed time ta represents the end of the aging period performed during the head chip 310's manufacture. The representative characteristics of head chip 310 are shown as solid lines CR1, CR2, and CR3 in descending order of ejection volume Ci1, Ci2, and Ci3 at the time aging is complete. Naturally, the characteristics of head chip 310 vary widely, but for ease of understanding, three representative examples of large, medium, and small ejection volumes are given.

[0081] As shown in the figure, the ejection characteristics of the head chip 310 vary over time, but overall they have a strong correlation with the initial characteristic values. Therefore, the ejection volume at time ta can be used to rank the head chips 310 according to their degree of deterioration, and this can be used to select the head chips 310 to be subjected to the recombination process (step S131).

[0082] A method for ranking the head chip 310 based on the degree of deterioration will be described. In FIG. 10B, the three representative examples are further illustrated by a solid line, a dashed line indicating an example of characteristics on the side with a higher ejection volume, and a dashed double-dashed line indicating an example of characteristics on the side with a lower ejection volume. The differences between these are explained using the characteristic CR1 for the highest initial ejection volume as an example. Of the characteristic CR1, the solid line Cc1, which begins at the time ta when aging is complete, indicates the change in ejection characteristics when the ambient temperature Ta during use of the head chip 310 is 25°C, which is assumed to be room temperature, and the reference voltage Vm of the drive signal COM is the average voltage Vav. Furthermore, the dashed line Cc2 indicates the change in ejection characteristics when the ambient temperature Ta during use of the head chip 310 is 15°C, which is lower than room temperature, and the reference voltage Vm of the drive signal COM is a voltage Vs lower than the average voltage Vav. Furthermore, the two-dot chain line Cc3 shows the change in ejection characteristics when the ambient temperature Ta during use of the head chip 310 is 45°C, which is higher than room temperature, and the reference voltage Vm of the drive signal COM is a voltage Vl that is higher than the average voltage Vav. This change in characteristics also applies to the characteristics CR2 and the like.

[0083] As shown in Figure 10B, the ejection performance of the head chip after a predetermined aging period changes with increasing ejection frequency, but the degree of change is affected by factors such as environmental temperature and the reference voltage Vm of the drive signal COM. For the head chip 310 used in the first liquid ejection head 3a, the initial characteristic values ​​and subsequent changes in characteristics due to use were examined for each parameter that affects the ejection characteristics, such as environmental temperature and the reference voltage Vm of the drive signal COM. Therefore, knowing the initial characteristic values ​​and parameters allows for highly accurate prediction of how the ejection characteristics will change with increasing ejection frequency. Therefore, as shown in an example in Figure 10B, by assuming ejection volume ranges such as a, b, c, and d based on the ejection volume achieved by aging as a reference, the rank of the head chip 310 at a given ejection frequency can be determined. This corresponds to ranking the head chip 310 based on the usage history for each initial characteristic value, i.e., by combining the initial characteristic value and usage history.

[0084] For example, if a head chip 310 with an ejection volume Ci1 as its initial characteristic value is used at an ambient temperature of 15°C and a reference voltage Vm of Vs, the rank based on the usage history of the head chip 310 at ejection time te is rank b based on the illustrated dashed-dotted line Cc2. Similarly, if a head chip 310 with an ejection volume Ci1 as its initial characteristic is used at an ambient temperature of 25°C and a reference voltage Vm of VAV, the rank based on the usage history of the head chip at ejection time te is rank c based on the illustrated solid line Cc1. If the head chip 310 is used at an ambient temperature of 45°C and a reference voltage Vm of Vl, the rank based on the usage history of the head chip 310 at ejection time te is rank d based on the illustrated dashed-dotted line Cc3.

[0085] Various usage histories can be combined with these initial characteristic values, including the ambient temperature and the reference voltage Vm. Representative parameters are listed below. Accumulated number of discharges (usage time): This has been described in detail above, so a detailed explanation will be omitted here. Note that the ranking of the degree of deterioration of the piezoelectric element 60 may be based only on the accumulated number of discharges (usage time), without using the usage history such as the ambient temperature and the reference voltage Vm. Ambient temperature during use: This is the temperature at which the head chip 310 is used. The ambient temperature during use of the head chip 310 is not necessarily the same, but an average temperature may be calculated and used as the ambient temperature, or the ambient temperature may be calculated for each period of use and the integrated value may be used as the ambient temperature parameter. In other words, the head chip 310 may be ranked a to d by combining the reference voltage Vm with the cumulative number of ejections (usage time) to rank the degree of deterioration of the piezoelectric element 60. Note that the head chip 310 may also be ranked a to d by combining only the cumulative number of ejections (usage time) and the ambient temperature during use without using the reference voltage Vm. Reference voltage Vm: The potential difference between the reference potential Vbs and the intermediate potential Vc of the drive signal COM applied to the head chip 310 described above. The voltage value itself may be used, or the voltage value may be divided into multiple categories and the category to which the reference voltage Vm belongs may be used. In other words, the head chip 310 may be classified into ranks a to d by combining the cumulative number of ejections (usage time) with the ambient temperature when the piezoelectric element 60 is used to rank the deterioration level of the piezoelectric element 60. Note that the head chip 310 may also be classified into ranks a to d by combining only the cumulative number of ejections (usage time) and the reference voltage Vm without using the ambient temperature when the piezoelectric element 60 is used. These ranks a to d are provided for ranks 1 and 2 of the initial characteristic values.

[0086] In addition to the parameters related to the degree of deterioration of the piezoelectric element 60, the following are typical parameters that can be used as characteristic information for ranking purposes based on the usage history. The following are parameters for estimating the degree of deterioration of elements other than the piezoelectric element 60. Ink filling time: The degree of deterioration of the adhesive used to form the head chip 310 affects the determination of whether the head chip 310 can continue to be used. The degree of adhesive deterioration is affected by the amount of time that ink has been filled in the common liquid chamber and pressure generating chamber 631 of the head chip 310. In other words, when ranking according to the degree of adhesive deterioration, the longer the ink filling time, the higher the rank of the head chip 310 that has been in the state of deterioration. Note that the type of ink filled may be combined with the ink filling time to more accurately estimate the degree of adhesive deterioration. For this reason, parameters such as the ink type as well as the ink filling time may be included in the usage history as characteristic information used in ranking. Number of wipings: Similarly, the degree of deterioration of water-repellent film 658 provided on head chip 310 affects the determination of whether head chip 310 can be used continuously. The degree of deterioration of water-repellent film 658 is affected by the number of wipings. In other words, when ranking according to the degree of deterioration of water-repellent film 658, the more the number of wipings, the higher the rank of head chip 310 classified as having a higher degree of deterioration. Note that by combining the number of wipings with the load with which wiping member WP presses water-repellent film 658 during wiping and the type of ink adhering to water-repellent film 658, ranking may be performed based on a more accurately estimated degree of deterioration of water-repellent film 658. For this reason, in addition to the number of wipings, parameters such as the wiping load and ink type may also be included in the usage history as characteristic information used for ranking. Number of cleaning processes: The degree of deterioration of nozzles 651 of head chip 310 can be grasped, for example, as the frequency or number of clogged nozzles. When a nozzle becomes clogged, a cleaning process is performed, so when ranking according to the degree of deterioration of nozzles 651, the more cleaning processes are performed, the higher the rank of the head chip 310 classified as having a higher degree of deterioration.

[0087] These parameters related to the usage history, that is, the cumulative number of ejections and the number of wiping operations that increase with use, the ambient temperature during use, the reference voltage Vm, and other histories, are counted by the printhead control circuit 71 of the printhead drive circuit board 7 and are written as needed to the memory 200 provided for each head chip 310 via the second interconnect board 335 and the first interconnect board 363. As mentioned above, the cumulative number of ejections may be substituted by the usage time of the head chip 310 or the head main body 31, etc. Furthermore, parameters such as the ambient temperature and the reference voltage Vm may be stored in the memory 200 provided in the second interconnect board 335. Alternatively, a memory may be provided in the first interconnect board 363 and stored in that memory.

[0088] Returning to FIG. 9, when the inspection device 65 is connected to the used first liquid ejection head 3a and the data is read, it is found that each head chip 310 has characteristics such as state HS1 or state HS2. Therefore, the head chips are selected based on the data or the rank to which the state belongs (step S131). In this embodiment, the head chips selected are the most deteriorated head chip and the least deteriorated head chip. Specifically, the head chip 310h shown in FIG. 8 is selected as the head chip with the highest degree of deterioration, and the head chip 310a is selected as the head chip with the lowest degree of deterioration.

[0089] Head chip 310h is included in head main body 31-4 located at the center of first liquid ejection head 3a, and because printer 100 transports print medium P to the center, it is highly likely to be used for printing, and in fact, its degree of deterioration was high. Note that head chip 310i adjacent to head chip 310h also has a high degree of deterioration, so in the head chip selection process (step S131), head chip 310i may be selected together with head chip 310h. The positions where these head chips 310h and 310i were located correspond to the "second position."

[0090] If head chip 310i is also selected as a head chip with a high degree of deterioration, head chip 310w, which was located in the low-frequency region PS, is also selected as a head chip with a low degree of deterioration. These head chips 511, 310w are head chips in which all or some of the nozzles Nz of the first liquid ejection head 3a have not been used to eject liquid, but they have been wiped and are still usable head chips. The positions where these head chips 511, 310w were located correspond to the "first position."

[0091] The head chip removal process (step S141) is a process of removing these selected head chips from the first liquid ejection head 3a. Here, at least the head chips 511 and 310h described above, and further the head chips 310i and 310w, are removed from the first liquid ejection head 3a. The removed head chips are incorporated into different positions of the first liquid ejection head 3a in step S161, but before that, if necessary, the removed head chips may be washed (step S151). Cleaning is not necessarily required if the removed head chips eject the same type of liquid, for example, ink of the same color and composition, after the recombination process.

[0092] The reassembly process (step S161) is shown in Figure 11. The figure shows that, of the head chips removed from the first liquid ejection head 3a, head chip 310h, which was located in the second position, has been installed in the first position of the second liquid ejection head 31x, and head chip 310a, which was located in the first position of the first liquid ejection head 3a, has been installed in the second position of the second liquid ejection head 31x. Similarly, head chip 310i and head chip 310w are installed with their second and first positions swapped.

[0093] After the above process, necessary data is written back to the memory 200 corresponding to each head chip 310, and the second liquid ejection head 31x is completed (step S171). This completes the manufacturing of the liquid ejection head.

[0094] According to the liquid ejection head manufacturing method of the first embodiment described above, in a used first liquid ejection head 3a, a head chip that has been used frequently and has a high degree of deterioration is replaced with a head chip that has not been used or has been used less frequently, i.e., has a low degree of deterioration, within the same first liquid ejection head 3a. Therefore, in the manufactured second liquid ejection head 31x, a head chip that was installed in the first position and has a low degree of deterioration is installed in the second position where the head chip that was installed in the first position had a high degree of deterioration. This allows for continued use and ultimately extends the life of the existing liquid ejection head. Furthermore, since the second liquid ejection head 31x is manufactured using the head chip that was installed in the first liquid ejection head 3a, there is no need to use a new head chip. This also contributes to resource conservation.

[0095] In this embodiment, the first positions are the ends of the first liquid ejection head 3a, which are considered to be used less frequently because the print medium P is transported to the center, and the head chips present there are used as the first head chips, but in this embodiment, data related to the ejection characteristics of the head chips is read from the first liquid ejection head 3a, so a head chip with a low degree of deterioration may be determined from the data related to the ejection characteristics and replaced with a head chip with a high degree of deterioration. In such a case, the total M head chips (here, n × m, i.e., 36) incorporated in the first liquid ejection head 3a may be assigned numbers according to the degree of deterioration, and the N head chips (N is an integer equal to or greater than 1 and less than M / 2) with the highest degree of deterioration may be replaced with the N head chips with the lowest degree of deterioration.

[0096] B. Second embodiment: Next, a manufacturing method of the second embodiment will be described. The liquid ejection head used in the manufacturing method of the liquid ejection head of the second embodiment is a liquid ejection head used in a so-called serial type printer 100B, unlike the line printer 100 of the first embodiment. The configuration of this printer 100B is shown in Fig. 12, and the configuration around the liquid ejection head is shown in Fig. 13.

[0097] (B1) Hardware configuration: 12 is a schematic diagram of a printer 100B incorporating a liquid ejection head 3B manufactured by the liquid ejection head manufacturing method of the second embodiment. This printer 100 is connected to a computer (hereinafter sometimes abbreviated as PC) 690 that outputs images, and prints an original image ORG output by the PC 690 onto a printing medium P. The printer 100B is a serial-type inkjet printer that prints using color inks. As shown in the figure, the printer 100B includes a mechanism that reciprocates the liquid ejection head 3B in the width direction of the printing medium P using a carriage motor 670, a mechanism that transports the printing medium P using a paper feed motor 674, a mechanism that drives the first liquid ejection head 3B to eject ink and form dots, and a control circuit board 720 that provides overall control. The control circuit board 720 not only directly drives the carriage motor 670 and paper feed motor 674, but also exchanges signals with the first liquid ejection head 3B via the drive circuit board 730, and with the PC 690 via the communication circuit board 710. It also exchanges signals with the display unit 677 and the like.

[0098] The printer 100B of this embodiment includes a mechanism that uses a carriage motor 670 to reciprocate a carriage 680 in the axial direction of a flat platen 676, and a mechanism that drives a first liquid ejection head 3B mounted on the carriage 680 to eject ink and form dots. The printer 100B also includes a feed position guide 678 that regulates the transport position of the print medium P to the center of the roller pair 675 in the width direction, regulating the transport position so that the print medium P passes through the center of the first liquid ejection head 3B regardless of the width of the print medium P. The mechanism that reciprocates the carriage 680 in the axial direction of the printer 100B of this embodiment includes a sliding shaft 673 that is installed parallel to the axis of the flat platen 676 and slidably holds the carriage 680, and a pulley 672 that tensions an endless drive belt 671 between the carriage motor 670 and the sliding shaft 673. Changing the printing position by moving the carriage 680 along the axial direction of the flat platen 676 is called main scanning, and this direction (bidirectional) is called the main scanning direction (Y direction). The roller pair 675 is connected to a paper feed motor 674, and changing the printing position by the first liquid ejection head 3B by transporting the printing medium P due to the rotation of the paper feed motor 674 is sometimes called sub-scanning in contrast to the above-mentioned main scanning. The sub-scanning direction is also called the X direction.

[0099] The carriage 680 is mounted with color ink cartridges 692-695, each containing cyan ink C, magenta ink M, yellow ink Y, and black ink K. Nozzle rows corresponding to the above-mentioned color inks are formed in the first liquid ejection head 3B at the bottom of the carriage 680. When these ink cartridges 692-695 are mounted on the carriage 680 from above, ink can be supplied from each cartridge to the first liquid ejection head 3B via an ink supply path (not shown).

[0100] The peripheral configuration of the first liquid ejection head 3B will be described with reference to FIG. 13. As shown, the first liquid ejection head 3B includes a head main body 740-1 and a head main body 740-2. Because both head main bodies have the same configuration, they are designated by the suffixes "-1" and "-2" only when necessary to distinguish them. The same applies to other components included in the head main bodies 740-1 and 740-2. Each head main body 740-1 and 740-2 includes four head chips 750. Drive signals are applied to these head chips 750 via first relay boards 745-1 and 745-2. The head main bodies 740-1 and 740-2 are provided with memories 743-1 and 743-2 that store data related to the status of the head chips 750. The status of the head chips 750 includes various information such as the usage history of the head chips 750 and the degree of deterioration that affects the ejection characteristics. Information that affects the ejection characteristics includes, in addition to the usage history, the initial characteristic values ​​of the head chip 310B, the environmental temperature during use, information about the type of ink used, the drive voltage waveform of the drive signal used in the printer 100B being used, etc. The memory 743 does not need to store all of this information; it is sufficient to store information required for the manufacturing method of the liquid ejection head, which will be described later, in particular information about the degree of deterioration.

[0101] The head bodies 740-1 and 740-2 are connected to a common second relay board 648. This second relay board 648 is connected to the drive circuit board 730. Therefore, in the printer 100B, the drive circuit board 730 outputs a drive signal based on instructions from the control circuit board 720, and the second relay board 648 distributes this drive signal into a signal for the head body 740-1 and a signal for the head body 740-2. The signals distributed for each ejection head are further output to each head chip 750 by the first relay board 745. The handling of data such as characteristic information for the head chip 750 provided in the first liquid ejection head 3B is the same as in the first embodiment. In addition, the reading device 665 can be connected to the second relay board 648 via a connector 661.

[0102] The detailed configuration of each head chip 750 in the first liquid ejection head 3B is shown in Fig. 14. The first liquid ejection head 3B of the second embodiment includes, as head chips 750, first head chips 561, 562, and 563 that eject cyan (C) ink, magenta (M) ink, and yellow (Y) ink for color printing, and a second head chip 564 that ejects black (K) ink for black printing.

[0103] The steps of the manufacturing method of the liquid ejection head in the second embodiment are the same as those of the manufacturing method in the first embodiment shown in FIG. 9, and therefore are not shown in the drawings. In the second embodiment, as shown in FIG. 15, the first head chip 562 for M ink and the second head chip 564 for K ink are rearranged, so cleaning (step S151) is necessary. In FIG. 15, the liquid ejection head before the rearrangement process (step S161) is shown as the first liquid ejection head 3B, and the liquid ejection head after the rearrangement process is shown as the second liquid ejection head 3y. Of these, in the first liquid ejection head 3B, in this embodiment, the position of the first head chip 562 for ejecting M ink corresponds to the first position. Also, the position of the second head chip 564 for ejecting K ink corresponds to the second position. Also, in the second liquid ejection head 3y after the rearrangement process, the position of the first head chip 564 for ejecting M ink corresponds to the corresponding first position. Also, the position of the second head chip 562 for ejecting K ink corresponds to the corresponding second position.

[0104] In this embodiment, the first head chips for the C, M, and Y inks used in color printing, which generally have a low ejection frequency and are less susceptible to deterioration, are cleaned and replaced with the second ink head for the K ink, which has a high ejection frequency and is more susceptible to deterioration. As a result, in the manufactured second liquid ejection head 3y, the K ink head chip 562 is replaced with a less deteriorated one, thereby extending the life of the second liquid ejection head 3y. Other effects are similar to those of the first embodiment. Here, the first head chip 564 ejecting the M ink is selected as the less deteriorated head chip 750 to be replaced. However, which C, M, or Y head chip to replace may be determined based on characteristic information stored for each head chip 750. The method of determining the replacement status based on characteristic information stored in memory 43 or the like is similar to that of the first embodiment.

[0105] C. Third embodiment: Next, a third embodiment will be described. The liquid ejection head manufactured in the third embodiment is a liquid ejection head for a printer 100B having the same configuration as that of the second embodiment, but the configuration of the head chips is different. As shown in FIG. 16, a first liquid ejection head 3C of the third embodiment has head bodies 740-1 and 740-2 having different configurations. Head body 740-1 has head chips 571, 572, 573, and 574, and head body 740-2 has head chips 581, 582, 583, and 584. The head chips of both head bodies 740-1 and 740-2 are arranged so as to be staggered in the Y direction.

[0106] The detailed arrangement of the head chips for both head bodies 740-1 is shown in FIG. 17. The arrangement order is the same for both head bodies 740-2. As shown in the figure, of these head chips, head chips 571 and 581 have two rows of nozzle groups for ejecting C ink and M ink. Head chips 574 and 584 also have two rows of nozzle groups for ejecting C ink and M ink, but their arrangement is reversed in the Y direction. Similarly, head chips 572 and 582 and head chips 573 and 583 have two rows of nozzle groups for ejecting Y ink and K ink, but their arrangement is reversed in the Y direction. Head body 740C equipped with such head chips is designed for bidirectional printing, and different head chip combinations are used for forward printing and reverse printing, so that the order of ink colors ejected onto print medium P is the same.

[0107] As a result of use of this first liquid ejection head 3C, defects df1 and df2 such as nozzle clogging occurred in head chip 571 and head chip 583, and as shown in Figure 16, banding Bn1 and Bn2 due to missing dots occurred when printing on printing medium P.

[0108] Therefore, as in the first and second embodiments, a head chip rearrangement process is performed. Because the manufacturing method is the same as in the other embodiments, illustration of the manufacturing process is omitted. The rearrangement is performed as follows. In FIG. 18, the liquid ejection head before the rearrangement process is shown as a first liquid ejection head 3C, and the one after the rearrangement process is shown as a second liquid ejection head 3z. Here, the first liquid ejection head 3C and the second liquid ejection head 3z are mounted on a carriage 680 that performs main scanning in a first direction (Y direction), which is the width direction of the printing medium P to which liquid is ejected, and sub-scanning in a second direction (X direction), which is the transport direction of the printing medium P. The first liquid ejection head 3C includes, among the multiple arranged head chips, a first head chip 573 and a second head chip 583 that is more deteriorated than the first head chip 573, as well as a third head chip 581 and a fourth head chip 571 that is more deteriorated than the third head chip 581. Here, the position of the first head 573 is the first position, and the position of the second head chip 583 is the second position. The first position and the second position are different positions in the X direction, which is the second direction, and the first head chip 573 and the second head chip 583 eject the same type of liquid (Y, K). For convenience of illustration, the head chips are abbreviated as "HC" in FIG. 18. The third head chip 581 and the fourth head chip 571 eject the same type of liquid (C, M). In the second liquid ejection head 3z, the fourth head chip 571 is disposed at the same position in the second direction (X direction) as the second head chip 583 incorporated in the corresponding first position, and the third head chip 581 is disposed at the same position in the second direction (X direction) as the first head chip 573 incorporated in the corresponding second position. In addition, in the second liquid ejection head 3z, the ejection of liquid is performed by the first head chip 573 and the third head chip 581 of the second liquid ejection head, and the other head chips 582 and 581.

[0109] In the third embodiment described above, the two liquid head bodies 740-1 and 740-2 constituting the second liquid ejection head 3z are positioned apart in the second direction. If a highly deteriorated head chip is present in each head body 740-1 or 740-2, the head chip is collected in one liquid ejection head, and liquid ejection continues using only the other liquid ejection head. As a result, the malfunction in the second liquid ejection head 3z can be resolved without using a new head chip, allowing the printer to continue to be used. Note that in the illustrated example, malfunctions df1 and df2 occurred in different liquid ejection heads. However, if malfunctions occurred in the second head chip 583 in the second position and the third head chip 581 in the fourth position, for example, both chips could be relocated to the first and third positions, respectively.

[0110] D. Other Embodiments: (1) The present disclosure can also be implemented in the following forms. One of them is a method for manufacturing a liquid ejection head, comprising: a preparation step of preparing a first liquid ejection head in which a first head chip is arranged at a first position among a plurality of arranged head chips and a second head chip, the second head chip having a degree of deterioration greater than that of the first head chip, is arranged at a second position; a removal step of removing the first head chip and the second head chip from the first liquid ejection head; and a reassembly step of incorporating the second head chip into the corresponding first position and the first head chip into the corresponding second position in a second liquid ejection head in which the head chip arranged at a corresponding first position corresponding to the first position of the first liquid ejection head is used less frequently than the head chip arranged at a corresponding second position corresponding to the second position of the first liquid ejection head. This allows a head chip with a degree of deterioration to be replaced with a head chip with a degree of deterioration less, thereby extending the life of the liquid ejection head.

[0111] This manufacturing method can be applied to the manufacture of liquid ejection heads that eject various liquids, such as ink, water, alcohol, liquid fuel, and chemical liquids. Liquid ejection is not limited to methods using electrostrictive elements such as piezoelectric elements; various methods can be used, such as a bubble jet method using a heater or a method using a pump. The ejection characteristics of the first and second head chips are affected by the state of the liquid ejection mechanism. For example, the ejection characteristics change depending on various factors, such as the degree of deterioration of the electrostrictive elements and the state of decline in ejection performance, as well as the components of the ejection mechanism, such as the deterioration of adhesives and the water-repellent film required for the liquid ejection mechanism. These characteristic characteristics can be recorded in the liquid ejection head and retrieved and referenced, or they can be obtained by removing the first and second head chips, attaching them to a measuring device, and measuring them.

[0112] If the condition of the head chip is, for example, the degree of deterioration, the initial characteristic values ​​of the ejection mechanism, the cumulative number of ejections, or the usage time may be recorded and used to determine the degree of deterioration of the head chip. Alternatively, the number of nozzles experiencing ejection problems due to clogged nozzles or cracks in the head chip may be used as an indicator of the degree of deterioration. Alternatively, the removed head chip may be attached to a measuring device to measure the ejection capacity and indicators of deterioration at that time, and this may be used to determine the degree of deterioration. In this case, the type and viscosity of the ejected liquid may also be taken into consideration. When recording the number of ejections, the temperature during ejection and the voltage applied to the ejection element may also be recorded and taken into consideration as appropriate. The temperature during ejection may be measured using a temperature sensor installed in the head chip, or the temperature may be obtained from the impedance of the piezoelectric element 60, etc.

[0113] (2) In the above configuration, the head chip of the first liquid ejection head at the second position may be used more frequently than the head chip of the first liquid ejection head at the first position. This allows the head chip that is used more frequently to be replaced, thereby contributing to extending the life of the head chip.

[0114] (3) In the above configuration, the plurality of head chips of the first liquid ejection head may include a plurality of nozzles capable of ejecting liquid ink during a printing operation, and the first head chip disposed at the first position of the first liquid ejection head may have at least some of the plurality of nozzles not used during the printing operation. In this way, a head chip that is highly deteriorated can be replaced with a head chip that has not been used until then, thereby extending the life of the liquid ejection head.

[0115] (4) In the above configuration, the second head chip may include a defective nozzle that does not eject ink normally. This allows the head chip including the defective nozzle to be reassembled, leading to the elimination of the defect. Note that a defective nozzle is not limited to a nozzle that cannot eject liquid, for example, a nozzle that has become clogged, but also includes a nozzle whose ejection function fluctuates, causing the droplet size to exceed or fall below a predetermined range.

[0116] (5) In the above configuration, the first liquid ejection head and the second liquid ejection head are mounted on a cartridge that performs a main scan in which the liquid moves relatively in a first direction, which is the width direction of the medium onto which the liquid is ejected, and a sub-scan in which the liquid moves relatively in a second direction, which is the transport direction of the medium, and the first liquid ejection head includes a third head chip and a fourth head chip that is more deteriorated than the third head chip among the arranged head chips, the first position and the second position are different positions in the second direction, the first head chip and the second head chip eject the same type of liquid, and the third head chip and the fourth head chip eject the same type of liquid, and in the second liquid ejection head, the fourth head chip is arranged at the same position in the second direction as the second head chip incorporated in the corresponding first position, and the third head chip is arranged at the same position in the second direction as the first head chip incorporated in the corresponding second position, and the ejection of the liquid may be performed by the first head chip and the third head chip of the second liquid ejection head. This makes it possible to resolve the problem when multiple head chips are highly deteriorated.

[0117] (6) In the above configuration, the first head chip and the second head chip may eject the same type of liquid. This makes it possible to eliminate the need to clean the head chips when rearranging the head chips. Of course, cleaning may be performed even when the same type of liquid is ejected.

[0118] (7) In the above configuration, the first head chip and the second head chip may eject different types of liquid, and a cleaning process may be further provided prior to the recombination process, in which the flow paths in the first head chip and the flow paths in the second head chip are respectively cleaned. This increases the options for head chips to be recombined, thereby broadening the range of head chips that can be used to manufacture liquid ejection heads.

[0119] (8) In the above configuration, the first liquid ejection head may be a line head in which the plurality of head chips are arranged with a longitudinal direction intersecting a transport direction of a medium onto which liquid is ejected, the first head chip being a head chip of the plurality of head chips of the first liquid ejection head arranged in an end region in the longitudinal direction, and the second head chip being a head chip of the plurality of head chips of the first liquid ejection head arranged in a central region in the longitudinal direction. This makes it easy to select a head chip that is used less frequently and a head chip that is less deteriorated in an apparatus that transports a medium at the center in the width direction of the medium.

[0120] (9) In the above configuration, the first liquid ejection head may be a line head in which the plurality of head chips are arranged with the longitudinal direction intersecting the transport direction of the medium onto which the liquid is ejected, and the first head chip may be one of the plurality of head chips of the first liquid ejection head arranged at one end region in the longitudinal direction, and the second head chip may be one of the plurality of head chips of the first liquid ejection head arranged at the other end region in the longitudinal direction. This makes it easy to select a head chip that is used less frequently or has less deterioration in an apparatus that transports media of different widths along one edge in the width direction of the medium. Including the configuration of (8) above, the second head chip may be identified by measuring the ejection characteristics of each head chip or reading data that can determine the ejection characteristics from a memory or the like.

[0121] (10) The above configuration may further include a selection step of selecting the first head chip and the second head chip to be assembled in the reassembly step based on the usage history of the plurality of head chips of the first liquid ejection head. In this way, the head chips are selected based on the usage history, and the selection of the head chips is based on the usage history, which can extend the life of the liquid ejection head.

[0122] In each of the above embodiments, some of the configurations implemented by hardware may be replaced with software. At least a portion of the configurations implemented by software may also be implemented by a discrete circuit configuration. Furthermore, when some or all of the functions of the present disclosure are implemented by software, the software (computer program) may be provided in a form stored on a computer-readable recording medium. The term "computer-readable recording medium" is not limited to portable recording media such as floppy disks and CD-ROMs, but also includes internal storage devices within a computer, such as various RAMs and ROMs, and external storage devices fixed to a computer, such as a hard disk. In other words, the term "computer-readable recording medium" has a broad meaning, including any recording medium capable of fixing data packets, not just temporarily.

[0123] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0124] 3, 3B, 3C...first liquid ejection head, 3x, 3y, 3z...second liquid ejection head, 4...storage section, 5...medium transport mechanism, 5a...first transport section, 5b...second transport section, 6...maintenance mechanism, 7...print head drive circuit board, 8...main circuit board, 9...information output mechanism, 10, 10a, 10b...liquid ejection device, 15-19...cable, 25a, 26a, 27a, 27b, 28a, 28b, 29a...connector, 30...drive circuit board, 31...head main body, 32...cover, 33...base member, 34...flow path member, 35...cover member, 37...spacing 40...supply pipe, 51a, 51b...transport rollers, 52a, 52b...follower rollers, 53a, 53b...drive motor, 54b...transport belt, 55b...tension roller, 56b...urging member, 57b...roller, 60...piezoelectric element, 63...connection cable, 65...reading device, 71...print head control circuit, 72...drive signal output circuit, 73...drive state detection circuit, 81...liquid ejection device control circuit, 82...signal conversion circuit, 83...time measurement circuit, 84...power supply circuit, 85...voltage detection circuit, 200, 201, 203...memory , 202...selector, 210...drive signal selection control circuit, 310...head chip, 311...flexible wiring board, 312...integrated circuit, 313...through hole, 314, 315...connector, 321...base portion, 322...extension portion, 324...opening, 331...supply hole, 332...accommodation portion, 333...opening, 334...step, 335...second relay board, 336...integrated circuit, 337...connector, 351, 352...opening, 360...holding member, 361...flow path member, 362...holder, 363...first relay board, 364...ink supply portion, 3 65...cable insertion hole, 366...cable, 367...holding portion, 368...connector, 381 to 385...screw, 600...discharge portion, 601...piezoelectric layer, 602, 603...electrodes, 710...case, 611...manifold, 720...protective substrate, 621...diaphragm, 622...holding portion, 730...pressure chamber substrate, 631...pressure generating chamber, 740...flow path substrate, 641...common flow path, 642...branch flow path, 743...communicating flow path, 644...individual flow path, 750...nozzle plate, 651...nozzle, 652...nozzle surface, 658...water-repellent film, 665...reading device

Claims

1. A method for manufacturing a liquid ejection head, comprising: a preparation step of preparing a first liquid ejection head in which a first head chip is arranged at a first position among a plurality of arranged head chips, and a second head chip that is more deteriorated than the first head chip is arranged at a second position; a removing step of removing the first head chip and the second head chip from the first liquid ejection head; a reassembly step of incorporating the second head chip into the corresponding first position and incorporating the first head chip into the corresponding second position in a second liquid ejection head in which the frequency of use of a head chip arranged at a corresponding first position corresponding to the first position of the first liquid ejection head is lower than the frequency of use of a head chip arranged at a corresponding second position corresponding to the second position of the first liquid ejection head; A method for manufacturing a liquid ejection head comprising:

2. The method for manufacturing a liquid ejection head according to claim 1 , wherein a frequency of use of the head chip at the second position of the first liquid ejection head is higher than a frequency of use of the head chip at the first position of the first liquid ejection head.

3. the plurality of head chips of the first liquid ejection head include a plurality of nozzles capable of ejecting liquid ink during a printing operation; The method for manufacturing a liquid ejection head according to claim 2 , wherein the first head chip arranged at the first position of the first liquid ejection head does not use at least a portion of the plurality of nozzles in the printing operation.

4. The method for manufacturing a liquid ejection head according to claim 3 , wherein the second head chip includes a defective nozzle that does not eject the ink normally.

5. the first liquid ejection head and the second liquid ejection head are mounted on a carriage that performs a main scan in which the first liquid ejection head and the second liquid ejection head move relatively in a first direction, which is a width direction of a medium onto which the liquid is ejected, and a sub scan in which the first liquid ejection head and the second liquid ejection head move relatively in a second direction, which is a transport direction of the medium; the first liquid ejection head includes a third head chip and a fourth head chip that is more deteriorated than the third head chip in the arranged plurality of head chips, the first position and the second position are different positions in the second direction, the first head tip and the second head tip eject the same type of liquid, the third head chip and the fourth head chip eject the same type of liquid, In the second liquid ejection head, the fourth head chip is disposed at the same position in the second direction as the second head chip incorporated in the corresponding first position, and the third head chip is disposed at the same position in the second direction as the first head chip incorporated in the corresponding second position, the liquid is ejected by the first head chip and the third head chip of the second liquid ejection head; The method for manufacturing a liquid ejection head according to claim 1 .

6. The method for manufacturing a liquid ejection head according to claim 1 , wherein the first head chip and the second head chip eject the same type of liquid.

7. the first head chip and the second head chip eject different types of liquid, The method further includes a cleaning step of cleaning the flow path in the first head chip and the flow path in the second head chip before the recombination step. The method for manufacturing a liquid ejection head according to claim 1 .

8. the first liquid ejection head is a line head in which the plurality of head chips are arranged with a longitudinal direction intersecting a transport direction of a medium onto which the liquid is ejected, the first head chip is a head chip arranged in an end region in the longitudinal direction among the plurality of head chips of the first liquid ejection head, the second head chip is a head chip arranged in a central region in the longitudinal direction among the plurality of head chips of the first liquid ejection head; The method for manufacturing a liquid ejection head according to claim 1 .

9. the first liquid ejection head is a line head in which the plurality of head chips are arranged with a longitudinal direction intersecting a transport direction of a medium onto which the liquid is ejected, the first head chip is a head chip arranged in one end region in the longitudinal direction among the plurality of head chips of the first liquid ejection head, the second head chip is a head chip arranged in the other end region in the longitudinal direction among the plurality of head chips of the first liquid ejection head; The method for manufacturing a liquid ejection head according to claim 1 .

10. a selection step of selecting the first head chip and the second head chip to be incorporated in the recombination step based on a usage history of the plurality of head chips of the first liquid ejection head, The method for manufacturing a liquid ejection head according to claim 1 .

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