CN114222665B

CN114222665B - Liquid ejecting apparatus, control method thereof, and recording medium storing program

Info

Publication number: CN114222665B
Application number: CN202080057191.9A
Authority: CN
Inventors: 吉田康成
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 2019-08-20
Filing date: 2020-08-04
Publication date: 2023-01-31
Anticipated expiration: 2040-08-04
Also published as: CN114222665A; JP7354667B2; JP2021030500A; WO2021033531A1

Abstract

The density difference among the plurality of actuators distributed to each power supply circuit can be suppressed, and the unevenness can be corrected appropriately. The control unit executes a distribution process (S24-S34) for distributing any one of the actuators to each power supply circuit, and an ejection process for driving the actuators by the power supply circuit distributed in the distribution process and ejecting liquid from the nozzles. After the distribution processing (S24-S34) and before the discharge processing, the control unit determines whether or not a concentration difference between a maximum value of the concentration of the liquid discharged from the nozzles and a minimum value of the concentration of the liquid discharged from the nozzles is less than a maximum value among the plurality of power supply circuits, and the predetermined value or less, in a specific circuit (S36), and when it is determined that the concentration difference is not less than the predetermined value (S36: NO), the distribution processing is executed again (S24-S34).

Description

Liquid ejecting apparatus, control method thereof, and recording medium storing program

Technical Field

The present invention relates to a liquid discharge apparatus including a plurality of actuators and a plurality of power supply circuits, a method of controlling the liquid discharge apparatus, and a program.

Background

Patent document 1 discloses the following cases: when unevenness correction (correction of variation in ejection characteristics for each nozzle) is performed, a plurality of power supply circuits are provided, and a plurality of grouped drive elements (actuators) are distributed to the power supply circuits.

Documents of the prior art

Patent literature

Patent document 1: japanese patent laid-open publication No. 2019-064151

Technical problems to be solved by the invention

In patent document 1, the density difference among the plurality of actuators assigned to each power supply circuit is not considered, and when the density difference is large, there is a problem that the unevenness cannot be corrected appropriately even if different voltages are output to each power supply circuit.

Disclosure of Invention

An object of the present invention is to provide a liquid discharge apparatus, a method of controlling the liquid discharge apparatus, and a program capable of appropriately correcting unevenness by suppressing a density difference among a plurality of actuators assigned to respective power supply circuits.

According to a first aspect of the present invention, there is provided a liquid ejecting apparatus comprising: a plurality of nozzles; a plurality of actuators provided for each of the plurality of nozzles; a plurality of power supply circuits that output voltages different from each other to the actuators to which the actuators have been assigned; and a control section that executes: a distribution process of distributing any one of the plurality of actuators to each of the plurality of power supply circuits; and an ejection process of ejecting the liquid from the plurality of nozzles by driving the plurality of actuators by each of the plurality of power supply circuits to which the distribution process is distributed, wherein after the distribution process and before the ejection process, the control unit executes a determination process of determining whether or not a concentration difference is equal to or less than a predetermined value in a specific circuit, which is one of the plurality of power supply circuits and in which the number of the actuators does not reach a maximum number predetermined for the power supply circuit, and a difference between a maximum value of a concentration of the liquid ejected from the nozzles and a minimum value of the concentration of the liquid ejected from the nozzles, and when the determination process determines that the concentration difference in the specific circuit is not equal to or less than the predetermined value, the control unit executes the distribution process again.

According to a second aspect of the present invention, there is provided a control method for controlling a liquid discharge apparatus including a plurality of nozzles, a plurality of actuators provided for the respective nozzles, and a plurality of power supply circuits that output voltages different from each other for the actuators that have been allocated among the plurality of actuators, wherein a distribution process of allocating any one of the plurality of actuators to each of the plurality of power supply circuits, and a discharge process of driving the plurality of actuators by each of the plurality of power supply circuits allocated by the distribution process to discharge liquid from the plurality of nozzles are performed, and a determination process of determining whether or not a concentration difference between a maximum value of a concentration of the liquid discharged from the nozzles and a minimum value of a concentration of the liquid discharged from the nozzles is equal to or less than a predetermined value in a specific circuit among the plurality of power supply circuits before the discharge process are performed after the distribution process and before the discharge process are performed, and the concentration difference is determined as a difference between a maximum value of the concentration of the liquid discharged from the nozzles and a minimum value of the concentration of the liquid discharged from the nozzles in the specific circuit, and the concentration difference is determined as the concentration difference in the specific circuit, and the distribution process is performed again when the concentration difference is equal to or less than the predetermined value in the specific circuit, and the determination process is performed, and the case where the distribution process is not performed.

According to a third aspect of the present invention, there is provided a program causing a liquid discharge apparatus including a plurality of nozzles, a plurality of actuators provided for respective ones of the plurality of nozzles, and a plurality of power supply circuits that output voltages different from each other for ones of the plurality of actuators that have been assigned to the plurality of actuators to function as: a distribution unit that distributes any one of the plurality of actuators to each of the plurality of power supply circuits; an ejection unit that ejects liquid from the plurality of nozzles by driving the plurality of actuators by each of the plurality of power supply circuits assigned by the assignment unit; and a determination unit that determines whether or not a concentration difference, which is a difference between a maximum value of a concentration of the liquid discharged from the nozzle and a minimum value of a concentration of the liquid discharged from the nozzle, in a specific circuit among the plurality of power supply circuits, the number of the actuators having not reached a maximum number defined for the power supply circuit, is equal to or less than a predetermined value after the distribution by the distribution unit and before the discharge by the discharge unit, and the distribution unit performs the redistribution when the determination unit determines that the concentration difference in the specific circuit is not equal to or less than the predetermined value.

According to the first to third aspects, it is possible to suppress the density difference among the plurality of actuators assigned to the respective power supply circuits and to appropriately correct the unevenness.

In the case where there are a plurality of the specific circuits, the control unit may execute the assignment process again when it is determined in the determination process that the density difference in at least one of the plurality of specific circuits is not equal to or less than the predetermined value. In this case, the above-described effect (effect of suppressing the density difference among the plurality of actuators assigned to the respective power supply circuits and appropriately correcting the unevenness) can be more reliably obtained.

In the above-described configuration, when a plurality of correspondence relationships between the plurality of power supply circuits and the plurality of actuators are included in the specific circuit having the concentration difference equal to or less than the predetermined value in the determination process, the control unit may execute the ejection process based on a correspondence relationship in which an average value of the concentration difference in the plurality of power supply circuits is smallest among the plurality of correspondence relationships. In this case, the above-described effect (effect of suppressing the density difference among the plurality of actuators assigned to the respective power supply circuits and appropriately correcting the unevenness) can be more reliably obtained.

Before the dispensing process, the control unit may execute a sorting process of sorting the plurality of actuators in order of concentration of the liquid discharged from the nozzles by driving the actuators, and in the dispensing process, the control unit may execute: a first determination step of assigning the plurality of actuators to one of the plurality of power supply circuits in the order sorted by the sorting process, and determining whether or not the concentration difference reaches a threshold value in the power supply circuit; and a second determination step of determining whether or not the number of the actuators allocated to the power supply circuit reaches the maximum number when it is determined in the first determination step that the concentration difference has not reached the threshold value, wherein the control unit executes the first determination step again for the power supply circuit when it is determined in the second determination step that the number of the actuators has not reached the maximum number, ends the allocation of the actuators to the power supply circuit when it is determined in the first determination step that the concentration difference has reached the threshold value, or executes the first determination step for an actuator that is not allocated to a power supply circuit other than the power supply circuit among the plurality of power supply circuits and to which the allocation of the actuators has not been completed among the plurality of actuators when it is determined in the second determination step that the number of the actuators has not reached the maximum number. In this case, the assignment process can be efficiently performed.

In the case where it is determined in the determination process that the density difference of the specific circuit is not equal to or less than the predetermined value and the assignment process is executed again, the control unit may execute the ejection process based on a correspondence relationship between the plurality of power supply circuits and the plurality of actuators that are the target of the most recent determination process when any of the plurality of actuators is not assigned to any of the plurality of power supply circuits by executing the first determination step and the second determination step.

In this case, the above-described effects (the effect of suppressing the density difference among the plurality of actuators distributed to the respective power supply circuits and appropriately correcting the unevenness) can be obtained by reliably distributing the actuators.

In the distribution process, when any one of the plurality of actuators is not distributed to each of the plurality of power supply circuits by executing the first determination step and the second determination step, the control unit may decrease the threshold value and execute the distribution process again. In this case, the actuators can be reliably distributed.

In the determination process, when it is determined that the density difference of the specific circuit is not equal to or less than the predetermined value, the control unit may decrease the threshold value and execute the assignment process again. In this case, the actuators can be reliably distributed.

The initial value of the threshold may be a value obtained by subtracting a minimum density among the plurality of actuators from a maximum density among the plurality of actuators, and dividing the value by the number of power supply circuits in which the number of actuators does not reach the maximum number when the plurality of actuators are sequentially assigned to each of the plurality of power supply circuits until the maximum number is reached. In this case, the assignment process can be efficiently performed.

In the case where there are a plurality of the specific circuits, the predetermined value may be a value based on an average value of the density differences in the plurality of specific circuits. In this case, the determination process can be executed efficiently, and the above-described effect (effect of suppressing the density difference among the plurality of actuators assigned to the respective power supply circuits and appropriately correcting the unevenness) can be obtained more reliably.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to suppress the concentration difference among the plurality of actuators distributed to the respective power supply circuits and appropriately correct the unevenness.

Drawings

Fig. 1 is a perspective view showing a multifunction device according to an embodiment of the present invention.

Fig. 2 is a perspective view showing a state in which a cover is closed in the complex machine of fig. 1.

Fig. 3 is a plan view showing the inside of the casing of the multifunction device of fig. 1.

Fig. 4 is a partial cross-sectional view of the head shown in fig. 3.

Fig. 5 is a plan view showing an upper portion of a casing of the multifunction device of fig. 1.

Fig. 6 is a side view showing an upper portion of a housing of the multifunction device of fig. 1.

Fig. 7 is a block diagram showing an electrical configuration of the complex machine of fig. 1.

Fig. 8 is a flowchart showing an unevenness correction program executed by the control unit of the multifunction device shown in fig. 1.

Fig. 9 is a flowchart showing a recording program executed by the control unit of the multifunction device of fig. 1.

Fig. 10 is a flowchart showing processing executed in a corresponding step of the unevenness correcting program.

Fig. 11 is an explanatory diagram showing an example in which actuators arranged in a density order are sequentially assigned to each power supply circuit.

Detailed Description

As shown in fig. 1 and 2, a multifunction peripheral 1 according to an embodiment of the present invention includes: a casing 1a, an ink jet type image forming section 10 provided inside the casing 1a, a flatbed type image reading section 50 provided on the upper portion of the casing 1a, a cover 1c attached to the upper portion of the casing 1a in an openable and closable manner, a paper feed tray 1m, and a paper discharge tray 1n.

As shown in fig. 3, the conveyance mechanism 20, the platen 30, and the control unit 90 are provided inside the casing 1a, in addition to the image forming unit 10.

The image forming unit 10 is a linear head unit that is long in the paper width direction (direction orthogonal to the vertical direction) and includes four heads 11. The four heads 11 each have a plurality of nozzles 11x, and are arranged in a staggered manner in the paper width direction.

As shown in fig. 4, each head 11 includes a flow path unit 11m and an actuator unit 11n.

The plurality of nozzles 11x are open on the lower surface of the flow path unit 11 m. Inside the flow path unit 11m, a general flow path 11a communicating with an ink tank (not shown) and a single flow path 11b independent of each nozzle 11x are formed. The single flow path 11b is a flow path extending from the outlet of the common flow path 11a to the nozzle 11x through the pressure chamber 11 p. The plurality of pressure chambers 11p are open on the upper surface of the flow path unit 11 m.

The actuator unit 11n includes: a metal diaphragm 11n1 disposed on the upper surface of the flow path unit 11m so as to cover the plurality of pressure chambers 11p, a piezoelectric layer 11n2 disposed on the upper surface of the diaphragm 11n1, and a plurality of cell electrodes 11n3 disposed on the upper surface of the piezoelectric layer 11n2 so as to face the respective pressure chambers 11p of the plurality of pressure chambers 11 p.

The vibration plate 11n1 and the plurality of cell electrodes 11n3 are electrically connected to the drive IC11 d. The drive IC11d changes the potential of the cell electrode 11n3 while maintaining the potential of the diaphragm 11n1 at the ground potential. Specifically, the drive IC11d generates a drive signal based on a control signal from the control unit 90, and applies the drive signal to the cell electrode 11n3 via the signal line 11 s. Thereby, the potential of the cell electrode 11n3 changes between the predetermined drive potential and the ground potential. At this time, the portions (actuators 11n 4) of the vibration plate 11n1 and the piezoelectric layer 11n2 sandwiched between the cell electrodes 11n3 and the pressure chambers 11p are deformed so as to protrude toward the pressure chambers 11p, whereby the volumes of the pressure chambers 11p are changed, and pressure is applied to the ink in the pressure chambers 11p, whereby the ink is ejected from the nozzles 11 x. The actuator 11n4 is provided to each cell electrode 11n3, and is capable of being independently deformed in accordance with a potential applied to the cell electrode 11n3.

The conveyance mechanism 20 includes a paper feed roller (not shown) and two roller pairs 21 and 22 (see fig. 3). The image forming unit 10 is disposed between the roller pair 21 and the roller pair 22 in the conveyance direction (direction orthogonal to the vertical direction and the paper width direction). When the transport motor 20m (see fig. 7) is driven under the control of the control unit 90, the sheet 100 placed on the sheet feed tray 1m (see fig. 1 and 2) is fed by the sheet feed roller, transported in the transport direction by the roller pairs 21 and 22, and stored in the sheet discharge tray 1n (see fig. 1 and 2).

As shown in fig. 5 and 6, the image reading section 50 includes a document table 60 formed of an upper portion of the housing 1a, and a reading unit 70 and a moving mechanism 80 disposed in the housing 1 a.

A transparent plate 61 made of plastic, glass, or the like is fitted into the document table 60. As shown in fig. 6, a sheet 100 to be read is placed on the upper surface of the light-transmitting plate 61.

The reading unit 70 has a line sensor 71 and a carriage 72 that holds the line sensor 71. The carriage 72 can be reciprocated in a moving direction (a direction parallel to the paper width direction shown in fig. 3 in the present embodiment) by a moving mechanism 80.

The line sensor 71 extends in a direction orthogonal to the moving direction and the vertical direction. The line Sensor 71 is a CIS (Contact Image Sensor) type (equal magnification optical system), and includes a plurality of light sources 71a each including light emitting diodes of three colors of RGB (red, green, and blue), a plurality of cylindrical equal magnification lenses 71b, and a plurality of reading elements 71c. Each read element 71c is made of, for example, CMOS (Complementary Metal Oxide Semiconductor).

As shown in fig. 1 and 2, the cover 1c is openable and closable with respect to the document table 60, and the cover 1c is closed to suppress light from outside from entering the reading unit 70 (see fig. 6).

The moving mechanism 80 includes: a guide 81 extending in the moving direction, a pair of

pulleys

82a, 82b disposed across the light-transmitting plate 61 in the moving direction, and a belt 83 wound around the

pulleys

82a, 82 b.

The carriage 72 is supported on the upper surface of the guide 81 and is fixed to the upper end surface of the belt 83. By the driving of the CIS moving motor 80m, the pulley 82a rotates, and the belt 83 travels, whereby the carriage 72 moves in the moving direction along the guide 81.

When reading an image of the sheet 100 placed on the transparent plate 61, the control unit 90 controls the CIS moving motor 80m to move the carriage 72 in the moving direction. The control unit 90 at this time turns on the plurality of light sources 71a and irradiates the paper 100 placed on the transparent plate 61 with light from each of the plurality of light sources 71 a. The light is reflected by the sheet 100 through the light-transmitting plate 61, passes through the lens 71b, and enters the reading element 71c. The reading element 71c converts the received light into an electric signal to generate read data of an image (data indicating the amount of received light), and outputs the read data to the control unit 90.

As shown in fig. 7, the control Unit 90 includes a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, and a RAM (Random Access Memory) 93. The ROM92 stores programs for the CPU91 to perform various controls. The RAM93 temporarily stores data used when the CPU91 executes programs. The CPU91 executes processing in accordance with programs and data stored in the ROM92 and the RAM93 based on data input from an external device (such as a PC) and an input unit (a switch and a button provided in the housing 1 a).

As shown in fig. 7, six power supply circuits 11e1 to 11e6 electrically connected to the driver IC11d are provided in each head 11. Each of the power supply circuits 11e1 to 11e6 may be a DC/DC converter including a plurality of electronic components such as FETs, inductors, resistors, and electrolytic capacitors.

The control unit 90 outputs a voltage designation signal for designating the output voltage of each of the power supply circuits 11e1 to 11e6 to each of the power supply circuits 11e1 to 11e6. The power supply circuits 11e1 to 11e6 output the output voltages specified by the voltage specification signals to the drive IC11 d. The voltages output from the six power supply circuits 11e1 to 11e6 are different from each other.

The drive IC11d is connected to each of the cell electrodes 11n3 of the plurality of cell electrodes 11n3 via a plurality of signal lines 11s (see fig. 4 and 7). Here, the control signal outputted from the control unit 90 to the drive IC11d includes a distribution signal for distributing one of the six power supply circuits 11e1 to 11e6 to each actuator 11n4. The drive IC11d generates a drive signal for each cell electrode 11n3 based on an output voltage from a power supply circuit distributed in accordance with the distribution signal, and applies the drive signal to each cell electrode 11n3 via the signal line 11 s.

Next, a program executed by the control unit 90 will be described with reference to fig. 8 and 9.

The control section 90 executes the unevenness correction program shown in fig. 8, for example, as a trigger such as switching the power supply of the multifunction device 1 from off to on, introducing ink from the ink tank to each head 11, or the elapse of a predetermined time from the execution of the latest unevenness correction program.

In the unevenness correction program, the control section 90 first forms an inspection image on the sheet 100 (S1).

In S1, the control unit 90 controls the drive IC11d and the transport motor 20m of each head 11, and ejects ink from the nozzles 11x of each head 11 while transporting the paper 100 in the transport direction by the transport mechanism 20. Thereby, dots are formed on the sheet 100, and an inspection image is formed.

After S1, the control unit 90 reads the inspection image formed in S1 (S2).

After S1 and before S2, the sheet 100 on which the inspection image is formed is placed on the light-transmitting plate 61 of the document table 60. For example, after moving the sheet 100 on which the inspection image is formed in S1 and which is accommodated in the discharge tray 1n onto the light-transmitting plate 61 of the document table 60, the user can instruct it via an input unit (a switch or a button provided in the housing 1 a) and, using this instruction as a trigger, start S2 by the control unit 90. Alternatively, the control section 90 may start S2 when a mechanism provided in the multifunction peripheral 1 triggers a case where the sheet 100, which has been formed with the inspection image in S1 and is accommodated in the discharge tray 1n, is moved onto the transparent plate 61 of the document table 60 and the sheet 100 is placed on the transparent plate 61.

In S2, the control unit 90 irradiates the inspection image with light from each light source 71a while moving the carriage 72 in the moving direction by driving the CIS moving motor 80m, and generates read data (data indicating the amount of light received) of the inspection image on the reading element 71c.

After S2, the control unit 90 associates the actuator 11n4 with each of the power supply circuits 11e1 to 11e6 based on the read data generated in S2 (S3). The specific processing of S3 is described in detail later.

After S3, the control unit 90 ends the unevenness correction routine.

After the unevenness correcting routine shown in fig. 8, the control section 90 executes a recording routine shown in fig. 9.

In the recording program, the control section 90 first determines whether or not a recording command is received (S11). A recording command is transmitted from an external device (such as a PC) and an input unit (a switch and a button provided in the housing 1 a) to the control unit 90.

If the recording command is not received (S11: no), the control section 90 repeats the process of S11.

When the recording command is received (yes in S11), the control section 90 forms an image on the paper 100 based on the image data included in the recording command (S12: discharge processing).

In S12 (discharge processing), the control section 90 controls the drive ICs 11d and the transport motors 20m of the heads 11 to discharge ink from the nozzles 11x of the heads 11 while transporting the paper 100 in the transport direction by the transport mechanism 20. Thereby, dots are formed on the paper 100, and an image is formed.

In S12 (discharge processing), the control unit 90 outputs a control signal including the distribution signal (signal for distributing one of the six power supply circuits 11e1 to 11e6 to each actuator 11n 4) obtained in the corresponding step (S3) of the unevenness correction program to the drive IC11 d. Thus, each actuator 11n4 is driven by a power supply circuit allocated among the six power supply circuits 11e1 to 11e6.

After S12 (discharge processing), the control unit 90 ends the recording process.

Next, a step (S3) corresponding to the unevenness correction program shown in fig. 8 will be described with reference to fig. 10 and 11.

In the corresponding step (S3), as shown in fig. 10, the control unit 90 first linearizes the concentration with respect to the voltage (S21). Specifically, the relationship between the voltage output to the drive IC11d and the density of the ink ejected from the nozzle 11x when the actuator 11n4 is driven by the drive signal generated by the voltage may be nonlinear. In this case, the read data generated in S2 is corrected so that the relationship becomes linear.

The read data generated in S2 is RGB luminance data, and the read data can be converted into CMYK density data. The control section 90 converts the read data generated in S2 into CMYK density data, and then performs the process in S21.

After S21, the control unit 90 sorts the plurality of actuators 11n4 in the order of density of the ink ejected from the nozzles 11x by the drive of the actuators, based on the data corrected in S21 (S22: sorting process). Fig. 11 shows an example in which the total of 1680 actuators 11n4 are arranged in order of concentration.

After S22 (sorting process), control unit 90 sets threshold T to initial value Ti (S23). The initial value Ti is a value obtained by dividing a value obtained by subtracting the minimum density Dmin in the plurality of actuators 11n4 from the maximum density Dmax in the plurality of actuators 11n4 by x (the number of power supply circuits in which the number of actuators 11n4 does not reach the maximum number when the plurality of actuators 11n4 are sequentially distributed to the six power supply circuits 11e1 to 11e6 until the maximum number is reached). The "maximum number" is the number of actuators 11n4 that can be assigned to the power supply circuits 11e1 to 11e6, is determined for each of the power supply circuits 11e1 to 11e6, and is stored in the ROM92. For example, when the total number of the actuators 11n4 is 1680 and the maximum number defined for each of the power supply circuits 11e1 to 11e6 is 540, and 540 actuators 11n4 are sequentially allocated to the first power supply circuit 11e1 to the third power supply circuit 11e3, the number of the remaining actuators 11n4 is 60 (less than 540), and the maximum number of actuators 11n4 cannot be allocated to the fourth power supply circuit 11e4 to the sixth power supply circuit 11e6. In this case, the number (x) of power supply circuits for which the number of actuators 11n4 does not reach the maximum number is "3". In this way, the value of x can be calculated based on the total number of actuators 11n4, the total number of power supply circuits 11e1 to 11e6, and the "maximum number" and stored in the ROM92.

After S23, the control section 90 sets n =1 (S24).

After S24, the control unit 90 allocates a predetermined number of the actuators 11n4 sorted in the density order in S22 (sorting process) to the nth power supply circuit in order from the actuator 11n4 having a smaller density (S25). The allocation data in S25 is stored in the RAM93.

After S25, the control unit 90 determines whether or not the density difference in the actuator 11n4 assigned to the nth power supply circuit reaches a threshold value (S26: first determination step). The "density difference" is a difference between the maximum value of the density in the plurality of actuators 11n4 to be assigned to the nth power supply circuit and the minimum value of the density in the plurality of actuators 11n4 to be assigned to the nth power supply circuit.

When the density difference does not reach the threshold (S26: no), the control unit 90 determines whether or not the number of actuators 11n4 allocated to the nth power supply circuit reaches the maximum number (S27: second determination step).

When the number of the actuators 11n4 has not reached the maximum number (no in S27), the control unit 90 determines whether or not the allocation of all the actuators 11n4 to the power supply circuit has been completed (S28).

When the distribution of all the actuators 11n4 to the power supply circuits is not completed (no in S28), the control unit 90 returns the process to S25, and distributes the actuators 11n4 whose distribution to the power supply circuits is not completed by a predetermined number to the nth power supply circuit in order from the actuator 11n4 having a lower density.

When the distribution of all the actuators 11n4 to the power supply circuits is completed (yes in S28), the control unit 90 ends the distribution to the actuators 11n4 of the nth power supply circuit (S29), and advances the process to S33.

When the density difference reaches the threshold value (yes in S26), or when the number of the actuators 11n4 reaches the maximum number (yes in S27), the control unit 90 ends the assignment to the actuators 11n4 of the nth power supply circuit (S30), and determines whether the assignment of all the actuators 11n4 to the power supply circuits is completed (S31).

If the distribution of all the actuators 11n4 to the power supply circuits is not completed (S31: no), the control unit 90 sets n = n +1 (S32), returns the process to S25, and distributes the actuators 11n4 whose distribution to the power supply circuits is not completed by a predetermined number to the nth power supply circuit in order from the actuator 11n4 having a smaller density.

When the distribution of all the actuators 11n4 to the power supply circuit is completed (yes in S31), the control unit 90 advances the process to S33.

In S33, the control unit 90 determines whether n.gtoreq.6.

If n is not equal to or greater than 6 (no in S33), the control unit 90 sets a threshold T = T × 0.9 (S34), erases the allocation data stored in the RAM93, and returns the process to S24. That is, when the actuator 11n4 is not assigned to any one of the power supply circuits 11e1 to 11e6 (in other words, when any one of the actuators 11n4 of the plurality of actuators 11n4 is not assigned to each of the six power supply circuits 11e1 to 11e 6), the control unit 90 lowers the threshold T and executes the assignment process again (in other words, the assignment of the actuators 11n4 is resumed in order from the first power supply circuit 11e 1). By decreasing the threshold T and executing the distribution process again, the actuators 11n4 can be reliably distributed.

In the example of fig. 11 (a), the maximum number (540) of the actuators 11n4 is assigned to each of the first to third power supply circuits 11e1 to 11e3 (yes → S30, S27), the maximum insufficient number (50) of the actuators 11n4 is assigned to the fourth power supply circuit 11e4 (yes → S30, S26), the maximum insufficient number (10) of the actuators 11n4 is assigned to the fifth power supply circuit 11e5 (S28: yes → S29), and the actuators 11n4 is not assigned to the sixth power supply circuit 11e6. In this case, the control unit 90 determines whether n ≧ 6 is set (S33: no), sets the threshold T = T × 0.9 (S34), and resumes the allocation of the actuators 11n4 in order from the first power supply circuit 11e 1.

S24 to S34 correspond to "assignment processing". Through the distribution processing (S24 to S34), any one actuator 11n4 of the plurality of actuators 11n4 is distributed to each of the six power supply circuits 11e1 to 11e6.

If n ≧ 6 (S33: yes), control unit 90 determines whether n =6 (S35).

In the example of fig. 11 (b), the maximum number (540) of actuators 11n4 is allocated to each of the first power supply circuit 11e1 and the second power supply circuit 11e2 (S27: yes → S30), the less than maximum number (400, 190, 7) of actuators 11n4 is allocated to each of the third power supply circuit 11e3 to the fifth power supply circuit 11e5 (S26: yes → S30), and the less than maximum number (3) of actuators 11n4 is allocated to the sixth power supply circuit 11e6 (S28: yes → S29). In this case, the control unit 90 determines that n ≧ 6 (S33: YES), and further determines that n =6 (S35: YES).

If n =6 (yes in S35), the control unit 90 determines whether or not the density difference of the specific circuit ("specific circuit" means the power supply circuit in which the number of the actuators 11n4 does not reach the maximum number ") among the six power supply circuits 11e1 to 11e6 is equal to or less than a predetermined value (S36: determination processing).

When there are a plurality of specific circuits, the "predetermined value" may be a value based on an average value of density differences in the plurality of specific circuits (for example, the sum of the average value derived from the read data generated in S2 and the fixed value α stored in the ROM 92).

For example, in the example of fig. 11 (b), there are four specific circuits (third to sixth power supply circuits), the concentration difference among the plurality of actuators 11n4 allocated to the third power supply circuit is 11D (D: concentration 21336bit), the concentration difference among the plurality of actuators 11n4 allocated to the fourth power supply circuit is 10D, the concentration difference among the plurality of actuators 11n4 allocated to the fifth power supply circuit is 9D, and the concentration difference among the plurality of actuators 11n4 allocated to the sixth power supply circuit is 10D. In this case, the average value of the density differences in the four specific circuits is 10D, and if a fixed value α =0.5D is set, it is determined that the density difference (11D) in the first power supply circuit is not equal to or less than the predetermined value (average value + fixed value α = 10.5D) (S36: no).

If there are a plurality of specific circuits, if the density difference is not equal to or less than the predetermined value in at least one of the plurality of specific circuits (S36: no), the control section 90 returns the process to S34. That is, in this case, the control unit 90 sets the threshold T = T × 0.9 (S34), eliminates the assignment data stored in the RAM93, and executes the assignment process again (in other words, the assignment of the actuators 11n4 is resumed in order from the first power supply circuit 11e 1).

For example, in the example of fig. 11 (b), as described above, it is determined that the density difference of the first power supply circuit is not equal to or less than the predetermined value (S36: no), the threshold T = T × 0.9 is set, and the distribution processing is executed again (S24 to S34), so that the correspondence relationship of fig. 11 (c) is obtained. In the example of fig. 11 (c), there are four specific circuits (third to sixth power supply circuits), the concentration difference among the plurality of actuators 11n4 assigned to the third power supply circuit is 10.1D (D: concentration 21336bit), the concentration difference among the plurality of actuators 11n4 assigned to the fourth power supply circuit is 10.1D, the concentration difference among the plurality of actuators 11n4 assigned to the fifth power supply circuit is 9.8D, and the concentration difference among the plurality of actuators 11n4 assigned to the sixth power supply circuit is 10D. In this case, the average value of the density differences among the four specific circuits is 10D, and when a fixed value α =0.5D is set, it is determined that the density differences among all the specific circuits (third to sixth power supply circuits) are equal to or less than a predetermined value (average value + fixed value α = 10.5D) (S36: yes).

When the density difference of all the specific circuits is equal to or less than the predetermined value (yes in S36), the control section 90 determines whether or not the threshold T is smaller than the lower limit Tx (S37).

When the threshold T is not less than the lower limit value Tx (no in S37), the control unit 90 maintains the correspondence relationship between the power supply circuits 11e1 to 11e6 stored in the RAM93 and the actuator 11n4 at the determination time in S37, and returns the process to S34. That is, in this case, the control unit 90 holds the data relating to the correspondence relationship obtained in the present assignment process (S24 to S34), and creates and stores data relating to another correspondence relationship.

When the threshold value T is smaller than the lower limit value Tx (yes in S37), the control unit 90 determines whether or not there are a plurality of correspondences stored in the RAM93 (correspondences between the power supply circuits 11e1 to 11e6 and the actuator 11n4 including the specific circuit determined in S36 that the density difference is equal to or smaller than the predetermined value) (S38).

When there are a plurality of the correspondences (yes in S38), the control unit 90 holds the correspondence with the smallest average value of density differences among the six power supply circuits 11e1 to 11e6 among the plurality of correspondences in the RAM93, and eliminates the other correspondences from the RAM93 (S39).

For example, in the example of fig. 11 (c), it is determined that the threshold T is not less than the lower limit value Tx (S37: no), and the assignment process is executed again (S24 to S34) with the threshold T = T × 0.9 set, thereby obtaining the correspondence relationship of fig. 11 (d). In the example of fig. 11d, when it is determined that the threshold T is smaller than the lower limit Tx (yes in S37), the RAM93 is determined to have two correspondences of fig. 11 c and 11d at that time, and a plurality of correspondences stored in the RAM93 is determined (yes in S38). In this case, of the correspondence relationships shown in fig. 11 (c) and 11 (d), the RAM93 holds one correspondence relationship in which the average value of the density differences in the six power supply circuits 11e1 to 11e6 is small, and the other correspondence relationship is eliminated from the RAM93.

In the example of fig. 11 (e), the actuator 11n4 is distributed to a seventh power supply circuit without the head 11, in addition to the first to sixth power supply circuits 11e1 to 11e6. The example in fig. 11 (e) corresponds to a case where 90 actuators 11n4 out of 1680 in total are not distributed to any of the six power supply circuits 11e1 to 11e6 as a result of determining that the density difference of the specific circuit is not equal to or less than the predetermined value (S36: no) and executing the distribution process again (S24 to S34). In this case, the control unit 90 determines that n =6 is not satisfied (S35: no), and holds the correspondence relationship between the actuator 11n4 and the power supply circuits 11e1 to 11e6 that are the target of the latest S36 (determination processing) in the RAM93, and removes the correspondence relationship of fig. 11 (e) (that is, the correspondence relationship when n > 6) from the RAM93 (S40).

After S39, if there are not a plurality of correspondences (S38: no), or after S40, control unit 90 ends the flow.

The control section 90 executes S12 (discharge processing) in the recording program (fig. 9) based on the correspondence relationship stored in the RAM93 in the correspondence step (S3).

As described above, according to the present embodiment, as shown in fig. 10, when determining that the density difference of the specific circuit is not equal to or less than the predetermined value (S36: no), the control unit 90 executes the assignment process again (S24 to S34). This can suppress the density difference among the plurality of actuators 11n4 distributed to the power supply circuits 11e1 to 11e6, and appropriately correct the unevenness.

Further, according to the present embodiment, the process can be simplified by performing S36 (determination process) on the specific circuit in which the number of the actuators 11n4 does not reach the maximum number, without performing S36 (determination process) on all the power supply circuits 11e1 to 11e6.

When there are a plurality of specific circuits, the control unit 90 performs the assignment process again (S24 to S34) when determining that the density difference in at least one of the plurality of specific circuits is not equal to or less than the predetermined value (S36: no). In this case, the above-described effect (effect of suppressing the density difference among the plurality of actuators 11n4 distributed to the power supply circuits 11e1 to 11e6 and appropriately correcting the unevenness) can be obtained more reliably.

When there are a plurality of correspondences between the power supply circuits 11e1 to 11e6 including the specific circuit determined that the density difference is equal to or less than the predetermined value (yes in S36) (yes in S38), the control unit 90 executes S12 (discharge processing) based on the correspondence relation (S39) in which the average value of the density differences is the smallest among the six power supply circuits 11e1 to 11e6 among the plurality of correspondences. In this case, the above-described effect (effect of suppressing the density difference among the plurality of actuators 11n4 distributed to the power supply circuits 11e1 to 11e6 and appropriately correcting the unevenness) can be obtained more reliably.

The control unit 90 executes S22 (sorting process) before the assignment process (S24 to S34), assigns the actuator 11n4 to one of the six power supply circuits 11e1 to 11e6 in the order sorted by S22 (S25), and determines whether or not the density difference in the power supply circuit reaches the threshold value (S26: first determination step). Then, when determining that the density difference does not reach the threshold value (S26: no), the control unit 90 determines whether or not the number of the actuators 11n4 allocated to the power supply circuit reaches the maximum number (S27: second determination step), and when determining that the number of the actuators 11n4 does not reach the maximum number (S27: no), executes S26 again for the power supply circuit (first determination step). When determining that the density difference reaches the threshold value (yes in S26) or when determining that the number of the actuators 11n4 reaches the maximum number (yes in S27), the control unit 90 ends the distribution to the actuators 11n4 of the power supply circuit (S30), and performs S26 on the power supply circuit different from the power supply circuit among the six power supply circuits 11e1 to 11e6 (S32) and on the actuator among the plurality of actuators 11n4 to which the distribution is not completed (first determination step). In this case, the assignment process (S24 to S34) can be efficiently executed.

When it is determined that the density difference of the specific circuit is not equal to or less than the predetermined value (no in S36), the distribution process is executed again (S24 to S34), and S26 (first determination step) and S27 (second determination step) are executed, so that there is a case where any one actuator 11n4 of the plurality of actuators 11n4 is not distributed to any one power supply circuit of the six power supply circuits 11e1 to 11e6 (no in S35, refer to fig. 11 (e)). In this case, the control unit 90 executes S12 (discharge processing) based on the correspondence relationship (S40) between the actuator 11n4 and the power supply circuits 11e1 to 11e6 that are the target of the closest S36 (determination processing). In this case, it is possible to obtain (an effect of suppressing the density difference among the plurality of actuators 11n4 distributed to the power supply circuits 11e1 to 11e6 and appropriately performing the unevenness correction) while reliably performing the distribution of the actuators 11n4.

In the distribution processing (S24 to S34), when any one of the plurality of actuators 11n4 is not distributed to each of the six power supply circuits 11e1 to 11e6 by executing S26 (first determination step) and S27 (second determination step) (S33: no), the control unit 90 lowers the threshold T (S34) and executes the distribution processing again (S24 to S34). In this case, the actuators 11n4 can be reliably distributed.

When determining that the density difference of the specific circuit is not equal to or less than the predetermined value (no in S36), the control unit 90 lowers the threshold T (S34) and executes the assignment process again (S24 to S34). In this case, the actuators 11n4 can be reliably distributed.

The initial value Ti of the threshold T is a value obtained by dividing a value obtained by subtracting the minimum density Dmin in the plurality of actuators 11n4 from the maximum density Dmax in the plurality of actuators 11n4 by x (the number of power supply circuits in which the number of actuators 11n4 does not reach the maximum number when the plurality of actuators 11n4 are sequentially distributed to the six power supply circuits 11e1 to 11e6 until the maximum number is reached). In this case, the assignment process (S24 to S34) can be efficiently executed.

When there are a plurality of specific circuits, the predetermined value may be a value based on an average value of density differences in the plurality of specific circuits. In this case, the determination process of S36 can be executed efficiently, and the above-described effect (effect of suppressing the density difference among the plurality of actuators 11n4 distributed to the power supply circuits 11e1 to 11e6 and appropriately correcting the unevenness) can be obtained more reliably.

< modification example >

While the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made within the scope of the claims.

For example, in the above-described embodiment, the dispensing is performed sequentially from the actuator having a small density, but the dispensing may be performed sequentially from the actuator having a large density. In the actuators arranged in the density order, the density change is smaller (in the example of fig. 11, the density is smaller) and the density is sequentially distributed, so that the distribution can be performed up to the maximum number in the first half and the density difference does not reach the threshold, and thus the distribution process can be efficiently performed.

In the case where there are a plurality of specific circuits, in the above-described embodiment, the assignment process is executed again when it is determined that the density difference in at least one of the plurality of specific circuits is not equal to or less than the predetermined value (S36: no), but the present invention is not limited to this, and the assignment process may be executed again when it is determined that the density difference in all of the specific circuits is not equal to or less than the predetermined value (S36: no).

The predetermined value is not limited to a value based on an average value of density differences in a plurality of specific circuits (for example, the sum of the average value derived from the read data generated in S2 and the fixed value α stored in the ROM 92), and may be a fixed value β stored in the ROM92.

The initial value of the threshold is not limited to the values exemplified in the above embodiments.

In the case of lowering the threshold value, the threshold value is multiplied by 0.9 in the above-described embodiment, but the present invention is not limited thereto. For example, the threshold value may be multiplied by an arbitrary decimal other than 0.9, may be divided by an arbitrary number exceeding 1, or may be subtracted by an arbitrary positive number. In addition, the threshold value may be decreased in different widths in the first S34 and the second S34.

The actuator is not limited to the piezoelectric type, and may be of another type (for example, a thermosensitive type using a heating element, an electrostatic type using an electrostatic force, or the like).

In the above embodiment, the header is a line type, but may be a tandem type.

The head can eject a liquid other than ink (for example, a treatment liquid which causes components in the ink to aggregate or precipitate).

The recording medium is not limited to paper, and may be, for example, cloth, a resin member, or the like.

The liquid ejecting apparatus according to the present invention is not limited to a multifunction printer (that is, an apparatus having an image forming unit but no image reading unit may be used). The present invention can also be applied to printers, facsimile machines, copiers, and the like. The present invention is also applicable to a liquid ejecting apparatus used for applications other than image recording (for example, a liquid ejecting apparatus that ejects a conductive liquid onto a substrate to form a conductive pattern).

The inspection image may be read by a device different from the liquid ejecting apparatus according to the present invention (S2), and then the liquid ejecting apparatus according to the present invention may execute the associating step based on the read data received from another device (S3). For example, the inspection image may be read using a spectrophotometer ("spectroeye" manufactured by X-Rite corporation) (S2). In this case, the liquid ejecting apparatus according to the present invention may execute the associating step (S3) based on the read data received from the spectrophotometer.

The program according to the present invention may be recorded on a portable recording medium such as a flexible disk or a fixed recording medium such as a hard disk and distributed, or may be distributed via a communication line.

According to a reference example of the present invention, there is provided "a liquid ejecting apparatus including: a plurality of nozzles; a plurality of actuators provided for the respective nozzles of the plurality of nozzles; a plurality of power supply circuits that output voltages different from each other to the actuators to which the actuators have been assigned; and a control unit that executes a distribution process of distributing each of the plurality of actuators to any one of the plurality of power supply circuits and distributing any one of the plurality of actuators to each of the plurality of power supply circuits, in such a manner that a concentration difference of the liquid discharged from the nozzles among the actuators distributed to each of the plurality of power supply circuits is equal to or less than a predetermined value, and a control method of controlling a liquid discharge apparatus including a plurality of nozzles, a plurality of actuators provided respectively for each of the plurality of nozzles, and a plurality of power supply circuits to which the distributed actuators output voltages different from each other among the plurality of actuators, in the actuators distributed to each of the plurality of power supply circuits, a distribution process of distributing each of the plurality of actuators to any one of the plurality of power supply circuits and distributing any one of the plurality of actuators to each of the plurality of power supply circuits, wherein the distribution process is performed by causing a liquid discharge apparatus including a plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and a plurality of power supply circuits that output voltages different from each other for the distributed actuators to the plurality of actuators to function as a distribution unit that distributes each of the plurality of actuators to any one of the plurality of power supply circuits and distributes any one of the plurality of actuators to each of the plurality of power supply circuits, wherein the distribution process is performed by "distributing each of the plurality of actuators to any one of the plurality of power supply circuits and distributing any one of the plurality of actuators to each of the plurality of power supply circuits" and "one program, the concentration difference of the liquid discharged from the nozzles is set to be equal to or less than a predetermined value in the actuators assigned to the respective power supply circuits. In the present reference example, the determination process of S36 is not limited to the specific circuit in which the number of the actuators 11n4 is less than the maximum number, and the determination process of S36 may be performed for all the power supply circuits 11e1 to 11e6.

Description of the symbols

1. Compound machine (liquid spraying device)

10. Image forming apparatus with a toner cartridge

11e1 to 11e6 power supply circuits

11n4 actuator

11x nozzle

90. Control unit

Claims

1. A liquid ejecting apparatus includes:

a plurality of nozzles;

a plurality of actuators provided for the respective nozzles of the plurality of nozzles;

a plurality of power supply circuits that output voltages different from each other to the assigned ones of the plurality of actuators; and

a control part for controlling the operation of the display device,

the control section executes the following processing:

a distribution process of distributing any one of the plurality of actuators to each of the plurality of power supply circuits; and

an ejection process of ejecting the liquid from the plurality of nozzles by driving the plurality of actuators by each of the plurality of power supply circuits allocated by the allocation process,

after the dispensing process and before the ejection process,

the control unit executes a determination process of determining whether or not a density difference, which is a difference between a maximum value of a density of the liquid discharged from the nozzle and a minimum value of the density of the liquid discharged from the nozzle, in a specific circuit, which is one of the plurality of power supply circuits and in which the number of the actuators does not reach a maximum number defined for the power supply circuit, is equal to or less than a predetermined value,

in the case where it is determined in the determination process that the density difference of the specific circuit is not equal to or less than the predetermined value, the control section executes the assignment process again.

2. The liquid ejection device according to claim 1,

in the case where there are a plurality of the specific circuits, the control unit may execute the assignment process again when it is determined in the determination process that the density difference in at least one of the plurality of specific circuits is not equal to or less than the predetermined value.

3. The liquid ejection device according to claim 1 or 2,

when a plurality of the power supply circuits and the plurality of actuators are associated with each other, the plurality of power supply circuits including the specific circuit having the density difference determined to be equal to or less than the predetermined value in the determination process,

the control unit executes the discharge processing based on a correspondence relationship, among the plurality of correspondence relationships, in which an average value of the density differences in the plurality of power supply circuits is minimum.

4. The liquid ejection device according to claim 1 or 2,

before the dispensing process, the control unit executes a sorting process of sorting the plurality of actuators in order of concentration of the liquid discharged from the nozzles by driving the actuators,

in the assignment process, the control section performs:

a first determination step of assigning the plurality of actuators to one of the plurality of power supply circuits in the order sorted by the sorting process, and determining whether or not the concentration difference reaches a threshold value in the power supply circuit; and

a second determination step of determining whether or not the number of actuators assigned to the power supply circuit has reached the maximum number when it is determined in the first determination step that the density difference has not reached the threshold value,

when it is determined in the second determination step that the number of the actuators has not reached the maximum number, the control unit executes the first determination step again for the power supply circuit,

when it is determined in the first determination step that the density difference has reached the threshold value, or when it is determined in the second determination step that the number of the actuators has reached the maximum number, the control unit ends the allocation of the actuators to the power supply circuit, and executes the first determination step for an actuator that is not allocated to the power supply circuit other than the power supply circuit among the plurality of power supply circuits and to an actuator that is not allocated among the plurality of actuators.

5. The liquid ejection device according to claim 4,

when it is determined in the determination process that the density difference of the specific circuit is not equal to or less than the predetermined value and the distribution process is executed again, if any one of the plurality of actuators is not distributed to any one of the plurality of power supply circuits by executing the first determination step and the second determination step,

the control unit executes the discharge processing based on a correspondence relationship between the plurality of power supply circuits and the plurality of actuators, which are objects of the most recent determination processing.

6. The liquid ejection device according to claim 4,

in the distribution process, when any one of the plurality of actuators is not distributed to each of the plurality of power supply circuits by executing the first determination step and the second determination step,

the control unit lowers the threshold and executes the assignment process again.

7. The liquid ejection device according to claim 4,

in the determination process, when it is determined that the density difference of the specific circuit is not equal to or less than the predetermined value, the control unit lowers the threshold value and executes the assignment process again.

8. The liquid ejection device according to claim 6 or 7,

the initial value of the threshold is a value obtained by subtracting the minimum density among the plurality of actuators from the maximum density among the plurality of actuators, divided by the number of power supply circuits for which the number of actuators does not reach the maximum number when the plurality of actuators are sequentially assigned to each of the plurality of power supply circuits until the maximum number is reached.

9. The liquid ejection device according to claim 1 or 2,

in the case where there are a plurality of the specific circuits, the predetermined value is a value based on an average value of the density differences in the plurality of specific circuits.

10. A control method for controlling a liquid ejecting apparatus including a plurality of nozzles, a plurality of actuators provided for the respective nozzles, and a plurality of power supply circuits for outputting different voltages to the actuators among the plurality of actuators to which the actuators have been allocated,

a dispensing process and a discharge process are performed,

the assigning process assigns any one of the plurality of actuators to each of the plurality of power supply circuits,

in the discharge process, the plurality of actuators are driven by each of the plurality of power supply circuits allocated by the allocation process to discharge the liquid from the plurality of nozzles,

after the dispensing process and before the ejection process,

executing a determination process of determining whether or not a density difference, which is a difference between a maximum value of the density of the liquid discharged from the nozzle and a minimum value of the density of the liquid discharged from the nozzle, in a specific circuit, which is one of the plurality of power supply circuits and in which the number of the actuators does not reach a maximum number defined for the power supply circuit, is equal to or less than a predetermined value,

when it is determined in the determination process that the density difference of the specific circuit is not equal to or less than the predetermined value, the assignment process is executed again.

11. A recording medium storing a program that causes a liquid discharge apparatus including a plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and a plurality of power supply circuits that output voltages different from each other to ones of the plurality of actuators that have been assigned to the plurality of actuators to function as:

a distribution unit that distributes any one of the plurality of actuators to each of the plurality of power supply circuits;

an ejection unit that ejects liquid from the plurality of nozzles by driving the plurality of actuators by each of the plurality of power supply circuits assigned by the assignment unit; and

a determination unit that determines whether or not a concentration difference between a maximum value of a concentration of the liquid discharged from the nozzle and a minimum value of a concentration of the liquid discharged from the nozzle is equal to or less than a predetermined value in a specific circuit among the plurality of power supply circuits, the specific circuit being one in which the number of the actuators does not reach a maximum number defined for the power supply circuits, after the dispensing by the dispensing unit and before the discharging by the discharging unit,

the dispensing unit performs re-dispensing in a case where it is determined by the determination unit that the density difference of the specific circuit is not equal to or less than the prescribed value.