Printing apparatus and printing method

Abstract

This invention relates to a printing apparatus and a printing method. A printing apparatus includes: a plurality of power circuits, each of which has a different output voltage; and a head including a plurality of nozzles arranged in a plurality of groups in a first direction, each of the nozzles being associated with any one of the plurality of power circuits. The plurality of groups includes a first group and a second group adjacent to each other in the first direction. The first group is formed by a plurality of nozzles associated with the first power circuit and a plurality of nozzles associated with the second power circuit. The second group is formed by a plurality of nozzles associated with the first power circuit and a plurality of nozzles associated with the second power circuit.

Description

Technical Field

[0001] This disclosure relates to a printing apparatus configured to eject ink from a nozzle and a printing method. Background Technology

[0002] An inkjet head driving device is known, comprising: an actuator disposed corresponding to a respective nozzle and configured to discharge an amount of ink from the nozzle corresponding to a respective driving signal; a storage device configured to store calibration data for leveling the ink discharge amount from the respective nozzle; a selection unit configured to select one of the driving signals based on the calibration data; and a driving unit configured to output the selected driving signal to one of the actuators (see Japanese Patent Application Publication No. 2008-162261). In this inkjet head driving device, the nozzles of the inkjet head are grouped according to the characteristics of the ink discharge amount from the nozzles. A calibration driving voltage is applied to each group. Summary of the Invention

[0003] However, the density difference between dots formed by nozzles belonging to the same group was not taken into account in the above inkjet head drive device.

[0004] The purpose of this disclosure is to reduce the density difference between dots formed by nozzles belonging to the same group, and to reduce the density difference between two adjacent groups, in a printing apparatus including an inkjet head (in which nozzles are grouped according to their discharge characteristics).

[0005] According to a first aspect of this disclosure, a printing apparatus is provided, the printing apparatus comprising:

[0006] Multiple power supply circuits, including at least a first power supply circuit and a second power supply circuit, each of the multiple power supply circuits having a different output voltage;

[0007] The head includes a plurality of nozzles formed in a plurality of groups arranged in a first direction, each of the plurality of nozzles being associated with any one of the plurality of power circuits;

[0008] The multiple groups include a first group and a second group that are adjacent to each other in the first direction.

[0009] The first group is formed by a plurality of nozzles associated with a first power supply circuit and a plurality of nozzles associated with a second power supply circuit, and

[0010] The second group is formed by a plurality of nozzles associated with the first power supply circuit and a plurality of nozzles associated with the second power supply circuit.

[0011] According to a second aspect of this disclosure, a printing method using a printing apparatus is provided, the printing apparatus comprising: a plurality of power circuits, the plurality of power circuits including at least a first power circuit and a second power circuit, each of the plurality of power circuits having a different output voltage; a head including a plurality of nozzles formed in a plurality of groups arranged in a first direction, each of the plurality of nozzles being associated with any one of the plurality of power circuits, the method comprising:

[0012] Liquid is discharged onto the printing medium from the multiple nozzles of the head; and

[0013] The printing media moves relative to the multiple nozzles.

[0014] The multiple groups include a first group and a second group that are adjacent to each other in the first direction.

[0015] The first group is formed by a plurality of nozzles associated with a first power supply circuit and a plurality of nozzles associated with a second power supply circuit, and

[0016] The second group is formed by a plurality of nozzles associated with the first power supply circuit and a plurality of nozzles associated with the second power supply circuit.

[0017] According to the first and second aspects of this disclosure, without adjusting the output voltage of the power supply circuit, it is possible to reduce the density difference between points formed by nozzles belonging to the same group and to reduce the density difference between two adjacent groups. Attached Figure Description

[0018] Figure 1 This is a plan view of an exemplary main configuration of the printing apparatus according to this embodiment.

[0019] Figure 2 This is a bottom view of an exemplary head according to this embodiment.

[0020] Figure 3 This is a block diagram of an exemplary configuration according to this embodiment, which includes a second substrate included in the header and a flexible circuit board connected to the second substrate.

[0021] Figure 4 An exemplary circuit configuration set in a driver IC is depicted.

[0022] Figure 5 An exemplary configuration of a waveform generation circuit disposed in a driver IC is depicted.

[0023] Figure 6 This is a flowchart outlining an overview of the printing process performed by the printing apparatus according to this embodiment.

[0024] Figure 7The state of classifying nozzles into groups during a temporary setup according to this embodiment is depicted.

[0025] Figure 8 An example of information stored in the non-volatile memory of the header according to this embodiment is depicted.

[0026] Figure 9A The description illustrates the state in which the association between the power circuit and some of the nozzles changes during the setup adjustment step according to this embodiment, and Figure 9B It depicts a portion of a dot matrix formed by the ejection of ink droplets from all the nozzles in the head after a change in the relationship between the power circuit and the nozzles.

[0027] Figure 10 A modified example of the header in this embodiment is depicted.

[0028] Figure 11 Another modified example of the header of this embodiment is depicted.

[0029] Figure 12 This is a plan view of another modified example of the head in this embodiment. Detailed Implementation

[0030] See Figure 1 Figures 9 and 9 illustrate a printing apparatus according to an embodiment of the present disclosure.

[0031] exist Figure 1 In this design, the upstream side of the printing medium P in the transport direction is defined as the front side of the printing device 1, and the downstream side of the printing medium P in the transport direction is defined as the rear side of the printing device. Further, the surface that transports the printing medium P (and...) Figure 1 The direction parallel to the paper surface and orthogonal to the conveying direction is defined as the media width direction. Figure 1 The left side is the left side of printing device 1, and Figure 1 The right side is the right side of printing device 1. The direction orthogonal to the transport surface of printing medium P (and...) Figure 1 The direction orthogonal to the paper surface is defined as the up-down direction of the printing device 1. Figure 1 The front side (front side) of the paper surface is defined as the top (upper side), and... Figure 1 The reverse side (other side) of the paper surface is defined as the bottom (lower side). In the following description, front, back, left, right, top (upper part), and bottom (lower part) are used appropriately. The media width direction is an exemplary "first direction" of this disclosure, and the transport direction is an exemplary "second direction" of this disclosure.

[0032] like Figure 1As defined in the document, the printing device 1 includes a housing 2, an impression roll 3, four thread ends 4, two conveyor rollers 5A and 5B, and a controller 7.

[0033] The printing cylinder 3 is placed flat within the housing 2. The printing medium P is placed on the upper surface of the printing cylinder 3. Four lead ends 4 are positioned above the printing cylinder 3, arranged in a front-to-back direction. A transport roller 5A is positioned on the front side of the printing cylinder 3, and a transport roller 5B is positioned on the rear side of the printing cylinder 3. The two transport rollers 5A and 5B are driven by an electric motor (not depicted) to transport the printing medium P on the printing cylinder 3 rearward. Although the printing apparatus 1 includes four lead ends 4 in this embodiment, the number of lead ends 4 is not limited to four.

[0034] like Figure 3 As depicted, the controller 7 includes a first substrate 71. The first substrate 71 includes a field-programmable gate array (FPGA) 771 and a read-only memory (ROM). Figure 3 (not depicted in the text), Random Access Memory (RAM, in Figure 3 The controller 7 includes an electrically erasable programmable read-only memory (EEPROM) 712 (not depicted in the image). The controller 7 interacts with or communicates with an external device 9 (such as a personal computer). When the controller 7 receives instructions from the external device 9 or from an operation unit (not depicted) provided for the printing device 1, the controller 7 controls the operation of the thread head 4 and the transport rollers 5A and 5B according to the programs(s) stored in the ROM. Instead of the FPGA 711, a central processing unit (CPU) or a microprocessor unit (MPU) can be used.

[0035] For example, controller 7 controls the motors driving conveyor rollers 5A and 5B to convey the printing medium P in the conveying direction. Further, controller 7 controls each line 4 to discharge ink onto the printing medium P. Thus, an image is printed on the printing medium P. The printing medium P can be a roll-type paper comprising a supply roller having an upstream end in the conveying direction and a return roller having a downstream end in the conveying direction. In this case, the supply roller can be attached to conveyor roller 5A on the upstream side in the conveying direction. The return roller can be attached to conveyor roller 5B on the downstream side in the conveying direction. Alternatively, the printing medium P can be a roll-type paper comprising only a supply roller having an upstream end in the conveying direction. In this case, the supply roller can be attached to conveyor roller 5A on the upstream side in the conveying direction.

[0036] The housing 2 includes four head-holding portions 8 corresponding to four thread ends 4. The head-holding portions 8 are arranged above the impression roll 3 at a position between the conveyor rollers 5A and 5B. The head-holding portions 8 are arranged in the front-to-back direction. Each of the head-holding portions 8 holds one corresponding thread end 4.

[0037] The four nozzles 4 dispense cyan (C), magenta (M), yellow (Y), and black (Y) ink respectively. Each of these inks is supplied from the corresponding ink container (not shown) to the corresponding nozzle 4.

[0038] like Figure 1 As depicted, each thread head 4 in this embodiment includes ten heads 11. The ten heads 11 are arranged in a zigzag pattern in the media width direction to form two arrays. Since ink of one color is supplied to one thread head 4, ink of that color is discharged from the ten heads 11 included in said one thread head 4. In this embodiment, the thread head 4 includes ten heads 11. However, the number of heads 11 is not limited to ten.

[0039] like Figure 2 As depicted, in this embodiment, 112 nozzles 11a are opened in the bottom surface of each head 11. The 112 nozzles 11a form 28 nozzle arrays c01 to c28 arranged in the media width direction. Each nozzle array is formed by four nozzles 11a arranged in a zigzag pattern in a direction intersecting the transport direction and the media width direction. The position of the respective nozzles 11a in the transport direction is defined as r1 to r4 from the front side to the rear side of the transport direction. Each head 11 includes two manifolds (not depicted). Ink is supplied from one of the two manifolds to the nozzles 11a forming nozzle arrays r1 and r2. Ink is supplied from the other of the two manifolds to the nozzles 11a forming nozzle arrays r3 and r4. The position of each nozzle 11a in each head 11 is uniquely specified by the nozzle array to which each nozzle 11a belongs and its position in the transport direction. Although each head 11 includes 112 nozzles 11a in this embodiment, the number of nozzles 11a is not limited to 112. Furthermore, the number of nozzle arrays is not limited to 28, and the number of nozzles included in each nozzle array is not limited to four. The number of manifolds provided in each head 11 is not limited to two. One manifold may be provided for each of the nozzle arrays r1 to r4, or each of the manifolds may be provided for one of the corresponding nozzle arrays r1 to r4 (i.e., a total of four).

[0040] Each head 11 includes the same number (described below) of drive elements 111, second substrate 50, and flexible circuit board 60 as nozzle 11a. The printing apparatus 1 of this embodiment includes four wire heads 4. Each wire head 4 includes ten heads 11. Therefore, the printing apparatus 1 includes 40 heads 11. Therefore, the number of second substrates 50 is 40, and the number of flexible circuit boards 60 connected to the second substrates 50 is 40. Although for convenience... Figure 3 Only one second substrate 50 and one flexible circuit board 60 are depicted, but the first substrate 71 of the controller 7 is connected to 40 second substrates 50.

[0041] The second substrate 50 includes an FPGA 51, a non-volatile memory 52 (such as an EEPROM), a D / A converter 20, power supply circuits 21 to 26, etc. Although the second substrate 50 includes six power supply circuits 21 to 26 in this embodiment, the number of power supply circuits is not limited to six. The flexible circuit board 60 includes a non-volatile memory 62 (such as an EEPROM), a driver IC 27, etc.

[0042] Under the control of FPGA 711 located in the first substrate 71, FPGA 51 outputs digital setting signals for setting the output voltage of each of the power supply circuits 21 to 26 to D / A converter 20.

[0043] D / A converter 20 converts the digital setting signal output from FPGA 51 into an analog setting signal, and then outputs it to each of power supply circuits 21 to 26.

[0044] Each of the power supply circuits 21 to 26 can be configured as a DC / DC converter using electronic components such as FETs, inductors, resistors, and electrolytic capacitors. Each of the power supply circuits 21 to 26 outputs an output voltage specified by a setting signal to the driver IC 27. In this embodiment, all of the power supply circuits 21 to 26 are configured to have different output voltages. Specifically, the output voltage of power supply circuit 21 is 22V, the output voltage of power supply circuit 22 is 21V, the output voltage of power supply circuit 23 is 20V, the output voltage of power supply circuit 24 is 19V, the output voltage of power supply circuit 25 is 18V, and the output voltage of power supply circuit 26 is 24V.

[0045] Power supply circuit 21 is connected to driver IC 27 via trace VDD1. Power supply circuit 22 is connected to driver IC 27 via trace VDD2. Power supply circuit 23 is connected to driver IC 27 via trace VDD3. Power supply circuit 24 is connected to driver IC 27 via trace VDD4. Power supply circuit 25 is connected to driver IC 27 via trace VDD5. Power supply circuit 26 is connected to driver IC 27 via trace HVDD. Power supply circuit 26 is connected to each drive element 111 described below via trace VCOM. Traces HVDD and VCOM branch off from the middle portion of the trace drawn from power supply circuit 26.

[0046] Power supply circuits 21 to 26 are respectively connected to waveform generation circuits 30(1) to 30(n) in driver IC 27 (in this embodiment, n is a natural number equal to or greater than 2, and n is equal to the number of driving elements 111 in head 11 (i.e., 112)).

[0047] Waveform generation circuits 30(1) to 30(n) are provided corresponding to the n driving elements 111 in each head 11. That is, waveform generation circuits 30(1) to 30(n) are provided corresponding to the n nozzles 11a in each head 11. Driver IC 27 is connected to n signal lines 34(1) to 34(n). Driver IC 27 is connected to the n driving elements 111 via the n signal lines 34(1) to 34(n). Each signal line 34 is connected to a separate electrode of the corresponding driving element 111.

[0048] The driver IC 27 includes n selectors 90(1) to 90(n) corresponding to the n driving elements 111. The respective selectors 90 are hardware components configured, for example, by a plurality of FETs formed in the driver IC 27.

[0049] The power supply circuit 26 can be used as the power supply voltage for the VCOM of the drive element 111, or it can be used as the high-side back gate voltage (HVDD) of the PMOS transistors 311 to 315 described below.

[0050] The non-volatile memory 62 stores a nozzle ID for identifying a corresponding nozzle 11a, a group ID for identifying a group of nozzles (described below) formed by the nozzles 11a, a column ID for identifying the nozzle array, a row ID for identifying the position of the nozzles 11a in the conveying direction, etc. Further, for example, such as... Figure 8 As described, the correspondences between n nozzles 11a and five power circuits 21 to 25, the correspondences between n nozzles 11a and groups (group IDs) g10 to g70, the correspondences between n nozzles 11a and nozzle arrays (column IDs) c01 to c70, and the correspondences between n nozzles 11a and their positions (row IDs) r01 to r24 in the conveying direction are stored as a table T in non-volatile memory 52. ​​Table T can be stored in non-volatile memory 62 disposed in flexible circuit board 60, instead of in non-volatile memory 52.

[0051] The driver IC 27 is connected to the FPGA 51 via control line 40 and n control lines 33(1) to 33(n). Control lines 33(1) to 33(n) are configured corresponding to the n waveform generation circuits 30(1) to 30(n). Signals for controlling the FETs provided to each waveform generation circuit 30 are transmitted to each control line 33. Each waveform generation circuit 30 generates a drive signal for driving each drive element 111 based on the aforementioned signals, and outputs the generated drive signal to each drive element 111 via the corresponding signal line 34.

[0052] The control signals used to control the n selectors 90(1) to 90(n) in the driver IC 27 are transmitted to the control line 40. The FPGA 51 controls the n selectors 90(1) to 90(n) and selects the power supply circuit used to generate the drive signal to be output to each signal line 34.

[0053] See Figure 4 The following describes an exemplary configuration of the circuitry in driver IC 27. Figure 4 As described, the driver IC 27 includes: n waveform generation circuits 30(1) to 30(n); and n selectors 90(1) to 90(n) respectively configured corresponding to the waveform generation circuits 30(1) to 30(n).

[0054] The driver IC 27 includes n of the above configurations, the number of which is the same as the number of nozzles. Therefore, as an example, the configuration of the circuit placed between the control line 33(1) and the signal line 34(1) is described below. In the driver IC 27, the selector 90(1) and the waveform generation circuit 30(1) are formed between the control line 33(1) and the signal line 34(1).

[0055] Control line 33(1) from FPGA 51 is connected to selector 90(1). Control line 33(1) branches off from the middle part of the route connecting FPGA 51 and selector 90(1), and control line SB(1) branching off from the middle part of control line 33(1) is connected to waveform generation circuit 30(1).

[0056] Selector 90(1) is connected to waveform generation circuit 30(1) via five control lines S1(1), S2(1), S3(1), S4(1) and S5(1). Selector 90(1) selects any one of the five control lines S1(1), S2(1), S3(1), S4(1) and S5(1) according to instructions from FPGA 51, and connects the selected line to control line 33(1).

[0057] The waveform generation circuit 30(1) is connected to five traces connected to traces VDD1 to VDD5, a trace connected to trace HVDD, and a trace connected to trace GND.

[0058] See Figure 5 The exemplary circuit configurations of waveform generation circuits 30(1) to 30(n) provided according to the first 11 of this embodiment are described below. Since waveform generation circuits 30(1) to 30(n) have the same configuration, only waveform generation circuit 30(1) is described. Waveform generation circuit 30(1) includes five P-type metal-oxide-semiconductor (PMOS) transistors 311 to 315 (in Figure 5Only two transistors are depicted in the diagram. The N-type metal-oxide-semiconductor (NMOS) transistor 32, resistor 35, etc. The waveform generation circuit 30 (1) is connected to the individual electrode of the drive element 111 via signal line 34 (1).

[0059] Each drive element 111 in this embodiment is a piezoelectric element, which includes a first active portion inserted between a single electrode and a first constant-potential electrode and a second active portion inserted between a single electrode and a second constant-potential electrode. Each of the drive elements 111 corresponds to one of the pressure chambers. Each drive electrode 111 therefore includes a capacitor 111b and a capacitor 111b'.

[0060] The five source terminals 311a to 315a of PMOS transistors 311 to 315 are connected to traces VDD 1 to VDD 5. The source terminal 32a of NMOS transistor 32 is connected to ground. That is, PMOS transistor 311 is connected to power supply circuit 21 via trace VDD1. PMOS transistor 312 is connected to power supply circuit 22 via trace VDD2. PMOS transistor 313 is connected to power supply circuit 23 via trace VDD3. PMOS transistor 314 is connected to power supply circuit 24 via trace VDD4. PMOS transistor 315 is connected to power supply circuit 25 via trace VDD5.

[0061] Control line S1(1) is connected to the gate terminal 311c of PMOS transistor 311. Control line S2(1) is connected to the gate terminal 312c of PMOS transistor 312. Control line S3(1) is connected to the gate terminal 313c of PMOS transistor 313. Control line S4(1) is connected to the gate terminal 314c of PMOS transistor 314. Control line S5(1) is connected to the gate terminal 315c of PMOS transistor 315. Control line SB(1) is connected to the gate terminal 32c of NMOS transistor 32.

[0062] The drain terminals 311b to 315b of five PMOS transistors 311 to 315 are connected to the first terminal of resistor 35. The drain terminal 32b of NMOS transistor 32 is connected to the first terminal of resistor 35. The second terminal of resistor 35 is connected to a single electrode of drive element 111 (the second terminal of capacitor 111b' and the first terminal of capacitor 111b). The first constant potential electrode of drive element 111 (the first terminal of capacitor 111b') is connected to VCOM, and the second constant potential electrode of drive element 111 (the second terminal of capacitor 111b) is connected to ground.

[0063] When FPGA 51 outputs a low-level signal (L signal) to control line 33(1), any one of the PMOS transistors 311 to 315 connected to the signal line selected by selector 90(1) becomes on. Capacitor 111b is charged and capacitor 111b' is discharged using a voltage supplied from any of power supply circuits 21 to 25. When FPGA 51 outputs a high-level signal (H signal) to control line 33(1), NMOS transistor 32 becomes on. Capacitor 111b' is charged and capacitor 111b' is discharged using a voltage output from any of power supply circuits 21 to 25. The drive element 111 is deformed by alternately charging and discharging each of capacitors 111b and 111b', causing ink to be ejected or sprayed from the opening of the corresponding nozzle 11b.

[0064] That is, the drive signal used to drive the drive element 111 is output to the control line 34 (1). The selection line 90 (1) selects any one of the five control lines S1 (1) to S5 (1) as the control line to be connected to the control line 33 (1), which allows any one of the five power supply circuits 21 to 25 to be selected as the power supply circuit for generating the drive signal.

[0065] The printing method using printing device 1 in this embodiment will then be described below. Figure 6 As described in the figure, the printing method using the printing device 1 in this embodiment mainly includes a temporary setting step S10, a test printing step S20, a setting adjustment step S30, and a main printing step S40.

[0066] In the temporary setup step S10, such as Figure 7 As depicted, the 112 nozzles 11a are classified into seven groups g10 to g70 for every four nozzle arrays. Specifically, nozzles 11a belonging to nozzle arrays c01 to c04 are associated with group g10. Nozzles 11a belonging to nozzle arrays c05 to c08 are associated with group g20. Nozzles 11a belonging to nozzle arrays c09 to c12 are associated with group g30. Nozzles 11a belonging to nozzle arrays c13 to c16 are associated with group g40. Nozzles 11a belonging to nozzle arrays c17 to c20 are associated with group g50. Nozzles 11a belonging to nozzle arrays c21 to c24 are associated with group g60. Nozzles 11a belonging to nozzle arrays c25 to c28 are associated with group g70. Group g10 is adjacent to group g20 in the media width direction. Group g30 is adjacent to group g20 in the media width direction on the opposite side from group g10. In this embodiment, the number of power supply circuits 21 to 26 is six, which is less than the number of groups g10 to g70 (i.e., seven). However, the number of power supply circuits can be the same as the number of groups.

[0067] Subsequently, any one of the power supply circuits 21 to 25 is associated with each of the groups, such that the seven groups have a uniform density of dots formed by ink droplets ejected from the nozzles 11a. For example, power supply circuit 21 is associated with the nozzles 11a forming groups g10, g20, g60, and g70, power supply circuit 22 is associated with the nozzles 11a forming groups g30 and g50, and power supply circuit 23 is associated with the nozzles 11a forming group g40. The ejection characteristics of the 112 nozzles 11a are affected by minute errors in the diameter of the nozzles 11a, manufacturing errors in the drive element 111, residual stress generated in the head 11 during manufacturing, etc., which gradually change the ejection characteristics of the 112 nozzles 11a depending on their position in the media width direction and the transport direction. Therefore, even if the same power supply circuit is associated with the nozzles 11a forming all groups (i.e., groups g10 to g70), the density of dots formed by ink droplets is not necessarily uniform.

[0068] Then, as Figure 8 As depicted, information regarding the position (column ID, row ID) of nozzle 11a, the group to which nozzle 11a belongs, and the power supply circuitry associated with nozzle 11a is stored in the non-volatile memory 52 of each of the 112 nozzles 11a. Figure 8 In the diagram, v01 to v05 indicate the identification of power supply circuits 21 to 25.

[0069] In the test printing step S20, test printing is performed on the printing medium P according to the association between the power supply circuit and each nozzle 11a set in the temporary setup step S10. Specifically, voltage is supplied from power supply circuit 21 to drive element 111 corresponding to the nozzle 11a included in group g10. Voltage is supplied from power supply circuit 22 to drive element 111 corresponding to the nozzle 11a included in group g20. Voltage is supplied from power supply circuit 23 to drive element 111 corresponding to the nozzle 11a included in groups g30 to g50. Voltage is supplied from power supply circuit 24 to drive element 111 corresponding to the nozzle 11a included in group g60. Voltage is supplied from power supply circuit 25 to drive element 111 corresponding to the nozzle 11a included in group g70. Test printing is performed on the printing medium P by ejecting ink droplets from the 112 nozzles included in groups g10 to g70.

[0070] In the setup adjustment step S30, the association between the power supply circuit and each nozzle 11a set in the temporary setup step S10 is corrected based on the printing results in the test printing step S20. In the temporary setup step S10, the power supply circuit is associated with the nozzles of each group. Therefore, in two adjacent groups in the media width direction, a density difference visible to the naked eye can occur between the point formed by ink droplets ejected from the nozzle 11a belonging to one of the two groups and the point formed by ink droplets ejected from the nozzle 11a belonging to the other of the two groups. In view of this, in the setup adjustment step S30, the user observes the printing results in the test printing step S20 with the naked eye and determines whether a density difference is generated in two adjacent groups in the media width direction. When no such density difference is generated (when the user cannot see the density difference with the naked eye), the association between the power supply circuit and the nozzles performed in the temporary setup step S10 is maintained, and the main printing step S40 is performed. When a density difference is generated (when the user can see the density difference with the naked eye), the association between the power supply circuit and the nozzles performed in the temporary setup step S10 is adjusted. The following text provides specific examples.

[0071] For example, when a user notices the printing result in test printing step S20 by observing it with the naked eye... Figure 7 When a density difference is generated between groups g10 and g20 and between groups g20 and g30 as depicted, the power supply circuit is adjusted in relation to the nozzles 11a belonging to groups g10, g20, and g30. For example, as Figure 9A As shown, in group g10, the power supply circuit 21 associated with the nozzle 11a forming the nozzle array r4 is changed to a power supply circuit 22 whose output voltage is the next minimum output voltage after power supply circuit 21. In group g20, the power supply circuit 21 associated with the nozzle 11a forming the nozzle arrays r3 and r4 is changed to power supply circuit 22. In group g30, the power supply circuit 22 associated with the nozzle 11a forming the nozzle array r1 is changed to power supply circuit 21. As described above, the output voltages of power supply circuits 21 to 25 are different from each other. The output voltage decreases sequentially in the order of power supply circuits 21, 22, 23, 24, and 25 (i.e., power supply circuit 21 has the maximum output voltage). Therefore, in this embodiment, different natural numbers are associated with power supply circuits 21 to 25. For example, the natural number n is associated with power supply circuit 21, the natural number m, which is different from the natural number n, is associated with power supply circuit 22, and the natural number I, which is different from the natural numbers n and m, is associated with power supply circuit 23. Specifically, the natural numbers 1 to 5 are associated with power supply circuits 21 to 25. Figure 9AIn the diagram, the number in each circle indicating one of the nozzles 11a indicates a natural number associated with the power circuit of that nozzle 11a. The power circuit associated with the nozzle is changed by rewriting the power circuit ID corresponding to the nozzle 11a. The power circuit ID is stored in... Figure 8 The non-volatile memory 52 described in the document.

[0072] That is, in the setting adjustment step S30, the association between the power supply circuit and the nozzle is adjusted such that each of the groups g10 to g30 is formed by a nozzle 11a associated with the power supply circuit 21 and a nozzle 11a associated with the power supply circuit 22. Specifically, group g10 includes 12 nozzles 11a forming nozzle arrays r1 to r3 and four nozzles 11a forming nozzle array r4. Power supply circuit 21 is associated with the 12 nozzles 11a forming nozzle arrays r1 to r3, and therefore, the natural number 1 is associated with the 12 nozzles 11a forming nozzle arrays r1 to r3. Power supply circuit 22 is associated with the four nozzles 11a forming nozzle array r4, and therefore, the natural number 2 is associated with the four nozzles 11a forming nozzle array r4. Therefore, the average value A1 of the natural numbers associated with the 16 nozzles 11a forming group g10 is 1.25 (=(12+8) / 16).

[0073] Group g20 includes eight nozzles 11a forming nozzle arrays r1 and r2 and eight nozzles 11a forming nozzle arrays r3 and r4. Power supply circuit 21 is associated with the eight nozzles 11a forming nozzle arrays r1 and r2, and therefore, the natural number 1 is associated with the eight nozzles 11a forming nozzle arrays r1 and r2. Power supply circuit 22 is associated with the eight nozzles 11a forming nozzle arrays r3 and r4, and therefore, the natural number 2 is associated with the eight nozzles 11a forming nozzle arrays r3 and r4. Therefore, the average value A2 of the natural numbers associated with the 16 nozzles 11a forming group g20 is 1.5 (=(8+16) / 16).

[0074] Group g30 includes four nozzles 11a forming nozzle array r1 and twelve nozzles 11a forming nozzle arrays r2 to r4. Power supply circuit 21 is associated with the four nozzles 11a forming nozzle array r1, and therefore, the natural number 1 is associated with the four nozzles 11a forming nozzle array r1. Power supply circuit 22 is associated with the twelve nozzles 11a forming nozzle arrays r2 to r4, and therefore, the natural number 2 is associated with the twelve nozzles 11a forming nozzle arrays r2 to r4. Therefore, the average value A3 of the natural numbers associated with the 16 nozzles 11a forming group g30 is 1.75 (=(4+24) / 16).

[0075] In the above-described setting adjustment step S30, the average value A1 (=1.25) associated with the nozzle 11 forming group g10 is different from the average value A2 (=1.5) associated with the nozzle 11 forming group g20, and the absolute value of the difference between the average value A1 and the average value A2 is less than one. Further, the average value A2 (=1.5) associated with the nozzle 11a forming group g20 is different from the average value A3 (=1.75) associated with the nozzle 11a forming group g30, and the absolute value of the difference between the average value A2 and the average value A3 is less than one. The average value A2 is a value between the average values ​​A1 and A3.

[0076] In the main printing step S40, voltage is supplied to the drive element 111 corresponding to each nozzle 11a according to the power circuit association information stored in the non-volatile memory 52. ​​Then, printing is performed on the printing medium P by ejecting ink droplets from the 112 nozzles 11a included in groups g10 to g70.

[0077] For example, ink droplets are formed on the printing medium P by ejecting ink droplets from nozzles 11a belonging to groups g10 to g30. Figure 9B A lattice of dots extending in the direction of media transport, as depicted in the image. Figure 9B In the diagram, a dot formed by an ink droplet ejected from a nozzle 11a is indicated by a circle. A white circle indicates a dot formed by an ink droplet ejected from the nozzle 11a associated with the natural number 1 (hereinafter referred to as "dot 1"). A shaded circle indicates a dot formed by an ink droplet ejected from the nozzle 11a associated with the natural number 2 (hereinafter referred to as "dot 2").

[0078] like Figure 9BAs depicted, group g10 includes a pattern (hereinafter referred to as "pattern 1112"), each of which is formed by three points 1 and one point 2. Pattern 1112 is repeated four times (periodically) in the width direction of the medium, such that pattern 1112 is arranged in the width direction of the medium. Group g20 includes a pattern (hereinafter referred to as "pattern 12"), each of which is formed by one point 1 and one point 2. Pattern 12 is repeated eight times (periodically) in the width direction of the medium, such that pattern 12 is arranged in the width direction of the medium. Group g30 includes a pattern (hereinafter referred to as "pattern 1222"), each of which is formed by one point 1 and three points 2. Pattern 1222 is repeated four times (periodically) in the width direction of the medium, such that pattern 1222 is arranged in the width direction of the medium. In this embodiment, pattern 1112 is repeated every 0.084 mm in group g10, pattern 12 is repeated every 0.042 mm in group g20, and pattern 1222 is repeated every 0.084 mm in group g30. Experiments conducted by the inventors(s) show that the periodically repeating pattern at intervals of 0.16 mm or less is not noticeable. However, it is desirable for the pattern to repeat every 0.1 mm or less.

[0079] In the specified example above, group g10 is an exemplary "first group" of this disclosure, group g20 is an exemplary "second group" of this disclosure, and group g30 is an exemplary "third group" of this disclosure. In the temporary setup step S10, the power supply circuit 21 associated with groups g10 and g20 is an exemplary "first power supply circuit" of this disclosure, and the power supply circuit 22 associated with group g30 is an exemplary "second power supply circuit" of this disclosure. The dot matrix formed by ejecting ink droplets from all the nozzles 11a forming group g10 is an exemplary "first dot matrix" of this disclosure. The dot matrix formed by ejecting ink droplets from all the nozzles 11a forming group g20 is an exemplary "second dot matrix" of this disclosure. Further, pattern 1112 is an exemplary "first pattern" of this disclosure, and pattern 12 is an exemplary "second pattern" of this disclosure.

[0080] In the above embodiment, when a user notices a density difference between two adjacent groups in the media width direction by observing the printing results in the test printing step S20 with the naked eye, the association between the power supply circuit and some of the nozzles forming each group is changed. Specifically, in each group, a particular power supply circuit associated with some of the nozzles 11a in the temporary setting step S10 is changed to a power supply circuit whose output voltage is the next minimum output voltage after a certain power supply circuit, or to a power supply circuit whose output voltage is the next maximum output voltage after a certain power supply circuit. Without changing the output voltage of each power supply circuit, this reduces the density difference between points formed by nozzles belonging to the same group and reduces the density difference between two adjacent groups in the media width direction.

[0081] In the above embodiment, in two adjacent groups in the medium width direction, the average value A1 of the natural number associated with the nozzle 11a forming one of the two groups is different from the average value A2 of the natural number associated with the nozzle 11a forming the other of the two groups. The absolute value of the difference between the average value A1 and the average value A2 is less than one. Therefore, the adjustment can be performed more accurately compared to the case where the same power supply circuit is associated with the nozzle 11a forming each group (i.e., the case of temporary setting step S10).

[0082] In the above embodiment, when the first group, the second group, and the third group are adjacent to each other in this order along the media width direction, the average value A2 of the natural numbers associated with the nozzle 11a forming the second group is a value between the average value A1 of the natural numbers associated with the nozzle 11a forming the first group and the average value A3 of the natural numbers associated with the nozzle 11a forming the third group. This can smoothly mitigate the distribution trend of density differences in the head 11.

[0083] In the above embodiments, for example, pattern 1112 is repeated at an interval of 0.084 mm in group g10, pattern 12 is repeated at an interval of 0.042 mm in group g20, and pattern 1222 is repeated at an interval of 0.084 mm in group g30. That is, in each group, the pattern is repeated periodically at an interval equal to or less than 0.1 mm. Therefore, whenever the pattern is repeated periodically, it cannot be perceived by human vision as a density non-uniformity.

[0084] The embodiments described above are merely examples of this disclosure and can be modified as appropriate. For example, in each group, the number and position of the nozzles 11a performing the power circuit replacement can be appropriately varied. In the above embodiments, pattern 1112 is repeated four times in group g10 and eight times in group g20. However, this disclosure is not limited thereto. Pattern 1112 can be repeated in at least a portion of the dot matrix formed by ejecting ink droplets from all the nozzles forming group g10, and pattern 12 can be repeated in at least a portion of the dot matrix formed by ejecting ink droplets from all the nozzles forming group g20.

[0085] In the above embodiment, the 112 nozzles 11a included in each head 11 are classified into seven groups in the medium width direction. However, this disclosure is not limited thereto. The 112 nozzles 11a included in each head 11 can be further divided in the conveying direction. For example, as Figure 10 As depicted, the 112 nozzles 11a included in each head 11 can be further divided in the conveying direction into groups g10 to g70 on the front side and groups g80 to g140 on the rear side. That is, groups g10 to g70 are adjacent to groups g80 to g140 respectively in the conveying direction. In this case, not only in two groups adjacent to each other in the medium width direction, but also in two groups adjacent to each other in the conveying direction, the density difference between two groups adjacent to each other in the conveying direction can be reduced by adjusting the association between the power supply circuit and the nozzles in a manner similar to that in the above embodiment. In this modified example, group g10 is an exemplary "first group" of this disclosure, group g20 is an exemplary "second group" of this disclosure, group g80 is an exemplary "fourth group" of this disclosure, and group g90 is an exemplary "fifth group" of this disclosure.

[0086] exist Figure 10In the modified example depicted, group g10 includes eight nozzles 11a forming nozzle arrays r1 and r2. Power supply circuit 21 is associated with the eight nozzles 11a forming nozzle arrays r1 and r2, and therefore, the natural number 1 is associated with the eight nozzles 11a forming nozzle arrays r1 and r2. Therefore, the average value A1 of the natural numbers associated with the eight nozzles 11a forming group g10 is 1 (=8 / 8). The same applies to group g20, i.e., the average value A2 of the natural numbers is 1 (=8 / 8). Group g30 includes four nozzles 11a forming nozzle array r1 and four nozzles 11a forming nozzle array r2. Power supply circuit 21 is associated with the four nozzles 11a forming nozzle array r1, and therefore, the natural number 1 is associated with the four nozzles 11a forming nozzle array r1. Further, power supply circuit 22 is associated with the four nozzles 11a forming nozzle array r2, and therefore, the natural number 2 is associated with the four nozzles 11a forming nozzle array r2. Therefore, the average value A3 of the natural numbers associated with the eight nozzles 11a forming group g30 is 1.5 (=(4+8) / 8). Group g80 includes eight nozzles 11a forming nozzle arrays r3 and r4. Power supply circuit 21 is associated with four nozzles 11a forming nozzle array r3, and therefore, the natural number 1 is associated with the four nozzles 11a forming nozzle array r3. Further, power supply circuit 22 is associated with four nozzles 11a forming nozzle array r4, and therefore, the natural number 2 is associated with the four nozzles 11a forming nozzle array r4. Therefore, the average value A4 of the natural numbers associated with the eight nozzles 11a forming group g80 is 1.5 (=(4+8) / 8). Group g90 includes eight nozzles 11a forming nozzle arrays r3 and r4. Power supply circuit 21 is associated with two nozzles 11a forming nozzle array r3, and therefore, the natural number 1 is associated with the two nozzles 11a forming nozzle array r3. Power supply circuit 22 is associated with two nozzles 11a forming nozzle array r3 and four nozzles 11a forming nozzle array r4, and therefore, the natural number 2 is associated with the two nozzles 11a forming nozzle array r3 and the four nozzles 11a forming nozzle array r4. Therefore, the average value A5 of the natural numbers associated with the eight nozzles 11a forming group g90 is 1.75 (=14 / 8). Group g100 includes eight nozzles 11a forming nozzle arrays r3 and r4. Power supply circuit 22 is associated with the eight nozzles 11a forming nozzle arrays r3 and r4, and therefore, the natural number 2 is associated with the eight nozzles 11a forming nozzle arrays r3 and r4. Therefore, the average value A6 of the natural numbers associated with the eight nozzles 11a forming group g100 is 2 (=16 / 8). Therefore, the difference between the average value A4 and A1 and the difference between the average value A5 and A2 have the same code (a positive value in this modified example).Furthermore, the difference between the average A5 and A2 and the difference between the average A6 and A3 have the same code (positive in this modified example).

[0087] In the above embodiment, only one color of ink is dispensed from one head 11. However, this disclosure is not limited thereto. For example, as Figure 11 As depicted, a head 11 may include an array of eight nozzles arranged in the conveying direction. Black ink can be discharged from four nozzle arrays r1 to r4 located on the front side of the conveying direction, while cyan ink can be discharged from four nozzle arrays r5 to r8 located on the rear side of the conveying direction. In this case, head 11 includes a first manifold, a second manifold, a third manifold, and a fourth manifold (the manifolds are not depicted in the figures). Black ink is supplied from the first manifold to two nozzle arrays r1 and r2. Black ink is supplied from the second manifold to two nozzle arrays r3 and r4. Cyan ink is supplied from the third manifold to two nozzle arrays r5 and r6. Cyan ink is supplied from the fourth manifold to two nozzle arrays r7 and r8. Similar to the embodiment described above, the nozzles 11a forming the four nozzle arrays located on the front side of the conveying direction can be classified into seven groups g10 to g70 in the media width direction, and the nozzles 11a forming the four nozzle arrays located on the rear side of the conveying direction can be classified into seven groups g80 to g140 in the media width direction. Then, the association between the power supply circuit and groups g10 to g70 can be adjusted similarly to the above embodiments, and the association between the power supply circuit and groups g80 to g140 can be adjusted similarly to the above embodiments. In this modified example, black ink is an exemplary "first liquid" of this disclosure, and cyan ink is an exemplary "second liquid" of this disclosure. In this modified example, magenta ink can be used instead of black ink, and yellow ink can be used instead of cyan ink.

[0088] exist Figure 11In the modified example depicted, group g10 includes 12 nozzles 11a forming nozzle arrays r1 to r3 and four nozzles 11a forming nozzle array r4. Power supply circuit 21 is associated with the 12 nozzles 11a forming nozzle arrays r1 to r3, and therefore, the natural number 1 is associated with the 12 nozzles 11a forming nozzle arrays r1 to r3. Power supply circuit 22 is associated with the four nozzles 11a forming nozzle array r4, and therefore, the natural number 2 is associated with the four nozzles 11a forming nozzle array r4. Thus, the average value A1 of the natural numbers associated with the 16 nozzles 11a forming group g10 is 1.25 (=(12+8) / 16). Group g20 includes eight nozzles 11a forming nozzle arrays r1 and r2 and eight nozzles 11a forming nozzle arrays r3 and r4. Power supply circuit 21 is associated with the eight nozzles 11a forming nozzle arrays r1 and r2, and therefore, the natural number 1 is associated with the eight nozzles 11a forming nozzle arrays r1 and r2. Power supply circuit 22 is associated with the eight nozzles 11a forming nozzle arrays r3 and r4, and therefore, the natural number 2 is associated with the eight nozzles 11a forming nozzle arrays r3 and r4. Therefore, the average value A2 of the natural numbers associated with the 16 nozzles 11a forming group g20 is 1.5 (=(8+16) / 16). Group g30 includes four nozzles 11a forming nozzle array r1 and 12 nozzles 11a forming nozzle arrays r2 to r4. Power supply circuit 21 is associated with the four nozzles 11a forming nozzle array r1, and therefore, the natural number 1 is associated with the four nozzles 11a forming nozzle array r1. Power supply circuit 22 is associated with the 12 nozzles 11a forming nozzle arrays r2 to r4, and therefore, the natural number 2 is associated with the 12 nozzles 11a forming nozzle arrays r2 to r4. Therefore, the average value A3 of the natural numbers associated with the 16 nozzles 11a forming group g30 is 1.75 (=(4+24) / 16). Group g80 includes four nozzles 11a forming nozzle array r5 and 12 nozzles 11a forming nozzle arrays r6 to r8. Power supply circuit 21 is associated with the four nozzles 11a forming nozzle array r5, and therefore, the natural number 1 is associated with the four nozzles 11a forming nozzle array r5. Power supply circuit 22 is associated with the 12 nozzles 11a forming nozzle arrays r6 to r8, and therefore, the natural number 2 is associated with the 12 nozzles 11a forming nozzle arrays r6 to r8. Therefore, the average value A4 of the natural numbers associated with the 16 nozzles 11a forming group g80 is 1.75 (=(4+24) / 16). Group g90 includes 12 nozzles 11a forming nozzle arrays r5 to r7 and four nozzles 11a forming nozzle array r8. Power supply circuit 22 is associated with the 12 nozzles 11a forming nozzle arrays r5 to r7, and therefore, the natural number 2 is associated with the 12 nozzles 11a forming nozzle arrays r5 to r7.Power supply circuit 23 is associated with the four nozzles 11a forming nozzle array r8, and therefore, the natural number 3 is associated with the four nozzles 11a forming nozzle array r8. Therefore, the average value A5 of the natural numbers associated with the 16 nozzles 11a forming group g90 is 2.25 (=(24+12) / 16). Group g100 includes eight nozzles 11a forming nozzle arrays r5 and r6 and eight nozzles 11a forming nozzle arrays r7 and r8. Power supply circuit 22 is associated with the eight nozzles 11a forming nozzle arrays r5 and r6, and therefore, the natural number 2 is associated with the eight nozzles 11a forming nozzle arrays r5 and r6. Power supply circuit 23 is associated with the eight nozzles 11a forming nozzle arrays r7 and r8, and therefore, the natural number 3 is associated with the eight nozzles 11a forming nozzle arrays r7 and r8. Therefore, the average value A6 of the natural numbers associated with the 16 nozzles 11a forming group g100 is 2.5 (=(16+24) / 16). Therefore, the differences between the average values ​​A4 and A1, A5 and A2, and A6 and A3 have the same code (positive values ​​in this modified example). According to this modified example, it is also possible to reduce the density difference between two adjacent groups in the media width direction in a head capable of discharging two inks that are very different from each other in physical properties (such as viscosity). In this modified example, the power supply circuit 23 associated with the natural number 3 is an exemplary "third power supply circuit" of this disclosure.

[0089] In the above embodiment, the association between the power circuit and the nozzle is temporarily set in the temporary setting step S10, and a test print is performed in the test print step S20. Then, in the setting adjustment step S30, the association between the power circuit and the nozzle is adjusted based on the print result of the test print step S20. However, this disclosure is not limited thereto. For example, in the temporary setting step S10, the main print step S40 can be performed without performing the test print step S20 and the setting adjustment step S30. During the main print step S40, the association between the power circuit and the nozzle can be adjusted depending on the print result. In this case, the density sensor can be disposed downstream of the four thread ends 4 in the transport direction, and the density sensor can detect the density at a position in the media width direction during the main print. When the density difference between two adjacent groups in the media width direction exceeds a predefined threshold, the association between the power circuit and some of the nozzles belonging to the two groups can be changed.

[0090] In the above embodiments and modified examples, the nozzle array is arranged in the conveying direction in the head 11. However, this disclosure is not limited thereto. For example, as Figure 12As depicted, only one nozzle array can be formed along the width of the medium in the first 11. A nozzle array can be divided into seven groups g10 to g70 along the width of the medium.

[0091] In the above embodiment, the printing device 1 performs printing on the printing medium P via a thread system in which ink is expelled from a thread 4 fixed to the printing device 1 and longer in the width direction of the medium. However, the printing device 1 can perform printing on the printing medium P via a serial head system in which the head 11 is carried on a carriage to move together with the carriage in the width direction of the medium.

[0092] In the above embodiments, the printing medium P is delivered while the lead 4 is fixed to the printing device 1. However, this disclosure is not limited thereto. It is only necessary for the printing medium P to move relative to the lead 4. For example, the lead 4 can be configured to move relative to the fixed printing medium P.

Claims

1. A printing device, characterized in that, include: Multiple power supply circuits, including at least a first power supply circuit and a second power supply circuit, each of the multiple power supply circuits having a different output voltage; The head includes a plurality of nozzles formed in a plurality of groups arranged in a first direction, each of the plurality of nozzles being associated with any of the plurality of power circuits; The plurality of groups includes a first group and a second group that are adjacent to each other in the first direction. The first group is formed by a plurality of nozzles associated with the first power supply circuit and a plurality of nozzles associated with the second power supply circuit, and The second group is formed by a plurality of nozzles associated with the first power circuit and a plurality of nozzles associated with the second power circuit. Here, the natural value n is associated with the first power supply circuit. Unlike the natural value m of the value n, which is associated with the second power supply circuit, In the first grouping, the value n is associated with the plurality of nozzles associated with the first power supply circuit, and the value m is associated with the plurality of nozzles associated with the second power supply circuit. In the second grouping, the value n is associated with the plurality of nozzles associated with the first power circuit, and the value m is associated with the plurality of nozzles associated with the second power circuit. The average value A1 associated with the plurality of nozzles forming the first group is different from the average value A2 associated with the plurality of nozzles forming the second group.

2. The printing apparatus according to claim 1, wherein, The absolute value of the difference between the average value A1 and the average value A2 is less than one.

3. The printing apparatus according to claim 1, in, The plurality of groups further includes a third group that is adjacent to the second group in the first direction and located on the side opposite to the first group relative to the second group. The third group is formed by a plurality of nozzles associated with the first power circuit and a plurality of nozzles associated with the second power circuit. In the third grouping, the value n is associated with the plurality of nozzles associated with the first power circuit, and the value m is associated with the plurality of nozzles associated with the second power circuit. The average value A2 is the value between the average value A1 and the average value A3 associated with the multiple nozzles forming the third group.

4. The printing apparatus according to claim 3, in, The plurality of nozzles are formed in a nozzle array arranged in a second direction intersecting the first direction, and Each of the plurality of nozzles included in each of the plurality of nozzle arrays belongs to any one of the plurality of groups.

5. The printing apparatus according to claim 4, wherein, The plurality of groups further includes a fourth group that is adjacent to the first group in the second direction and located on one side of the second direction relative to the first group, and a fifth group that is adjacent to the second group in the second direction and located on the same side of the second direction relative to the second group.

6. The printing apparatus according to claim 5, in, The first liquid is discharged from the plurality of nozzles forming the first group and the second group, and A second liquid, different from the first liquid, is discharged from a plurality of nozzles forming the fourth and fifth groups.

7. The printing apparatus according to claim 5 or 6, in, The fourth group is formed by a plurality of nozzles associated with the first power circuit and a plurality of nozzles associated with the second power circuit. The fifth group is formed by a plurality of nozzles associated with the first power circuit and a plurality of nozzles associated with the second power circuit. In the fourth and fifth groups, the value n is associated with the plurality of nozzles associated with the first power circuit, and the value m is associated with the plurality of nozzles associated with the second power circuit. The difference obtained by subtracting the average value A1 from the average value A4 and the difference obtained by subtracting the average value A2 from the average value A5 are both positive or both negative. The average value A4 is the average of the values ​​associated with the plurality of nozzles forming the fourth group, and the average value A5 is the average of the values ​​associated with the plurality of nozzles forming the fifth group.

8. The printing apparatus according to claim 5 or 6, in, The plurality of power supply circuits further include a third power supply circuit, which is associated with a natural value k that is different from the values ​​n and m. The fourth group is formed by a plurality of nozzles associated with the first power circuit and a plurality of nozzles associated with the second power circuit. The fifth group is formed by a plurality of nozzles associated with the second power circuit and a plurality of nozzles associated with the third power circuit. In the fourth grouping, the value n is associated with the plurality of nozzles associated with the first power circuit, and the value m is associated with the plurality of nozzles associated with the second power circuit. In the fifth group, the value m is associated with the plurality of nozzles associated with the second power circuit, and the value k is associated with the plurality of nozzles associated with the third power circuit. The difference obtained by subtracting the average value A1 from the average value A4 and the difference obtained by subtracting the average value A2 from the average value A5 are both positive or both negative. The average value A4 is the average of the values ​​associated with the plurality of nozzles forming the fourth group, and the average value A5 is the average of the values ​​associated with the plurality of nozzles forming the fifth group.

9. The printing apparatus according to claim 1 or 2, in, A first lattice extending in the first direction is formed by discharging droplets from all of the plurality of nozzles forming the first group. A second lattice extending in the first direction is formed by discharging droplets from all of the plurality of nozzles that form the second group. In at least a portion of the first dot matrix, a plurality of first patterns are formed in the first direction at intervals equal to or less than 0.16 mm. Each of the plurality of first patterns includes a first point and a second point. The first point is formed by droplets discharged from a nozzle associated with the first power circuit, and the second point is formed by droplets discharged from a nozzle associated with the second power circuit. In at least a portion of the second dot matrix, a plurality of second patterns are formed in the first direction at intervals equal to or less than 0.16 mm, each of the plurality of second patterns including the first dot and the second dot.

10. The printing apparatus according to claim 9, in, In at least a portion of the first dot matrix, the first pattern is formed in the first direction at intervals equal to or less than 0.1 mm, and In at least a portion of the second dot matrix, the second pattern is formed in the first direction at intervals equal to or less than 0.1 mm.

11. The printing apparatus of claim 1 or 2, further comprising a memory configured to store information indicating a correspondence between the plurality of nozzles and the plurality of groups, and a correspondence between the plurality of nozzles and the plurality of power circuits. in, Printing is performed by driving the head based on the information provided.

12. The printing apparatus according to claim 1 or 2, wherein, The number of the plurality of power supply circuits is equal to or less than the number of the plurality of groups.

13. A printing method using a printing apparatus, the printing apparatus comprising: Multiple power supply circuits, including at least a first power supply circuit and a second power supply circuit, each of the multiple power supply circuits having a different output voltage; A head, the head including a plurality of nozzles formed in a plurality of groups arranged in a first direction, each of the plurality of nozzles being associated with any one of the plurality of power supply circuits, characterized in that the method comprises: Liquid is discharged from the plurality of nozzles of the head onto the printing medium; and The printing medium moves relative to the plurality of nozzles. The plurality of groups includes a first group and a second group that are adjacent to each other in the first direction. The first group is formed by a plurality of nozzles associated with the first power supply circuit and a plurality of nozzles associated with the second power supply circuit, and The second group is formed by a plurality of nozzles associated with the first power circuit and a plurality of nozzles associated with the second power circuit. Here, the natural value n is associated with the first power supply circuit. Unlike the natural value m of the value n, which is associated with the second power supply circuit, In the first grouping, the value n is associated with the plurality of nozzles associated with the first power supply circuit, and the value m is associated with the plurality of nozzles associated with the second power supply circuit. In the second grouping, the value n is associated with the plurality of nozzles associated with the first power circuit, and the value m is associated with the plurality of nozzles associated with the second power circuit. The average value A1 associated with the plurality of nozzles forming the first group is different from the average value A2 associated with the plurality of nozzles forming the second group.

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