JP7354667B2 - Liquid discharge device, its control method and program - Google Patents

Description

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

Patent Document 1 discloses that in order to perform unevenness correction (correction of variations in ejection characteristics for each nozzle), a plurality of power supply circuits are provided and a plurality of grouped drive elements (actuators) are assigned to each power supply circuit. has been done.

JP2019-064151A

Patent Document 1 does not take into account the density difference between multiple actuators assigned to each power supply circuit, and if the density difference is large, unevenness correction cannot be performed appropriately even if different voltages are output for each power supply circuit. Problems can arise.

An object of the present invention is to provide a liquid ejection apparatus, a control method thereof, and a program therefor, which can suppress concentration differences among a plurality of actuators assigned to each power supply circuit and appropriately correct unevenness.

According to a first aspect of the present invention, different voltages are output to a plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and an assigned actuator among the plurality of actuators. The controller includes a plurality of power supply circuits and a control unit, and the control unit performs an assignment process of assigning one of the plurality of actuators to each of the plurality of power supply circuits, and a control unit that performs an assignment process of assigning one of the plurality of actuators to each of the plurality of power supply circuits; A discharge process is performed in which each of the power supply circuits drives the plurality of actuators to discharge liquid from the plurality of nozzles, and after the allocation process and before the discharge process, the plurality of power supplies Among the circuits, in a specific circuit that is a power supply circuit in which the number of actuators does not reach the maximum number determined for the power supply circuit, the maximum concentration of the liquid discharged from the nozzle and the concentration of the liquid discharged from the nozzle are determined. A determination process is executed to determine whether or not a concentration difference, which is a difference from a minimum concentration of the liquid, is less than or equal to a predetermined value, and in the determination process, if the concentration difference of the specific circuit is not less than or equal to the predetermined value There is provided a liquid ejecting device characterized in that, when it is determined, the allocation process is executed again.

According to a second aspect of the present invention, different voltages are output to the plurality of nozzles, the plurality of actuators provided for each of the plurality of nozzles, and the assigned actuator among the plurality of actuators. A control method for controlling a liquid ejecting device comprising a plurality of power supply circuits, the method comprising: an assignment process in which one of the plurality of actuators is assigned to each of the plurality of power supply circuits; a discharge process in which the plurality of actuators are driven by each of the plurality of power supply circuits to discharge liquid from the plurality of nozzles, and after the allocation process and before the discharge process, Among the plurality of power supply circuits, in a specific circuit that is a power supply circuit in which the number of actuators does not reach the maximum number determined for the power supply circuit, the maximum concentration of the liquid discharged from the nozzle and the A determination process is executed to determine whether or not a concentration difference, which is a difference from a minimum concentration of liquid ejected from a nozzle, is less than or equal to a predetermined value; A control method is provided, characterized in that if it is determined that the allocation process is not less than the value, the allocation process is executed again.

According to a third aspect of the present invention, different voltages are output to the plurality of nozzles, the plurality of actuators provided for each of the plurality of nozzles, and the assigned actuator among the plurality of actuators. a plurality of power supply circuits, and an assignment means for assigning one of the plurality of actuators to each of the plurality of power supply circuits, each of the plurality of power supply circuits assigned by the assignment means; a discharge means for driving the plurality of actuators to discharge liquid from the plurality of nozzles; and after allocation by the allocation means and before discharge by the discharge means, among the plurality of power supply circuits , in a specific circuit that is a power supply circuit in which the number of actuators does not reach the maximum number determined for the power supply circuit, the maximum concentration of the liquid discharged from the nozzle and the concentration of the liquid discharged from the nozzle are determined. A program that functions as a determining means for determining whether or not a density difference, which is a difference from a minimum density value, is less than or equal to a predetermined value, wherein the determining means determines whether or not the density difference of the specific circuit is less than or equal to the predetermined value. A program is provided, characterized in that, if it is determined that the allocation is not the same, the allocation means executes the allocation again.

According to the first to third aspects, density differences among a plurality of actuators assigned to each power supply circuit can be suppressed, and unevenness correction can be appropriately performed.

When there are a plurality of specific circuits, the control unit executes the allocation process again when it is determined in the determination process that the density difference is not equal to or less than the predetermined value in at least one of the plurality of specific circuits. You may do so. In this case, the above effect (the effect of suppressing density differences among the plurality of actuators assigned to each power supply circuit and appropriately performing unevenness correction) can be obtained more reliably.

When there is a plurality of correspondences between the plurality of power supply circuits and the plurality of actuators, including the specific circuit for which the concentration difference is determined to be equal to or less than the predetermined value in the determination process, the control unit The ejection process may be performed based on the correspondence relationship in which the average value of the concentration differences in the plurality of power supply circuits is the smallest among the correspondence relationships. In this case, the above effect (the effect of suppressing density differences among the plurality of actuators assigned to each power supply circuit and appropriately performing unevenness correction) can be obtained more reliably.

Before the allocation process, the control unit executes a sort process in which the plurality of actuators are sorted in order of concentration of liquid ejected from the nozzle by driving the actuators, and in the allocation process, the plurality of actuators are a first determination step of allocating 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 has reached a threshold value in the power supply circuit; If it is determined in the first determination step that the concentration difference has not reached the threshold, a second determination is made to determine whether the number of actuators assigned to the power supply circuit has reached the maximum number. If it is determined in the second determination step that the number of actuators has not reached the maximum number, the first determination step is executed again for the power supply circuit, and the first determination step If it is determined that the concentration difference has reached the threshold value in the second determination step, or if it is determined that the number of actuators has reached the maximum number in the second determination step, assigning the actuators to the power supply circuit. The first determination step may be executed for a power supply circuit other than the power supply circuit among the plurality of power supply circuits and for an actuator for which allocation has not been completed among the plurality of actuators. In this case, the allocation process can be executed efficiently.

When the concentration difference of the specific circuit is determined in the determination process to be not equal to or less than the predetermined value and the allocation process is executed again, the control unit may perform the first determination step and the second determination step. , when any of the plurality of actuators is not assigned to any of the plurality of power supply circuits, based on the correspondence between the plurality of power supply circuits and the plurality of actuators that are the most recent targets of the determination processing, The ejection process may be performed. In this case, the above effect (the effect of suppressing density differences among the plurality of actuators assigned to each power supply circuit and appropriately performing unevenness correction) can be obtained while ensuring the assignment of actuators.

In the allocation process, when any of the plurality of actuators is not allocated to each of the plurality of power supply circuits by executing the first judgment step and the second judgment step, the control unit sets the threshold value to the second judgment step. The allocation process may be executed again by lowering the allocation value. In this case, actuator assignment can be performed reliably.

If 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 unit may lower the threshold value and execute the allocation process again. In this case, actuator assignment can be performed reliably.

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

When there are a plurality of 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 judgment process can be executed efficiently, and the above effect (the effect of suppressing density differences among multiple actuators assigned to each power supply circuit and appropriately performing unevenness correction) can be obtained more reliably. can.

According to the present invention, density differences among a plurality of actuators assigned to each power supply circuit can be suppressed, and unevenness correction can be appropriately performed.

1 is a perspective view showing a multifunction peripheral according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state in which the cover is closed in the multifunctional device of FIG. 1; FIG. 2 is a plan view showing the inside of the casing of the multifunctional device in FIG. 1. FIG. FIG. 4 is a partial cross-sectional view of the head shown in FIG. 3; FIG. 2 is a plan view showing the upper part of the casing of the multifunctional device shown in FIG. 1. FIG. FIG. 2 is a side view showing the upper part of the casing of the multifunctional device shown in FIG. 1; FIG. 2 is a block diagram showing the electrical configuration of the multifunctional device shown in FIG. 1. FIG. FIG. 2 is a flow diagram showing an unevenness correction program executed by a control unit of the multifunction device shown in FIG. 1. FIG. FIG. 2 is a flowchart showing a recording program executed by a control unit of the multifunction device shown in FIG. 1. FIG. FIG. 7 is a flow diagram showing the processing executed in the association step of the unevenness correction program. FIG. 6 is an explanatory diagram showing an example in which actuators sorted in order of concentration are sequentially assigned to each power supply circuit.

As shown in FIGS. 1 and 2, a multifunction device 1 according to an embodiment of the present invention includes a housing 1a, an inkjet image forming unit 10 provided inside the housing 1a, and a housing 1a. It includes a flatbed type image reading section 50 provided at the top, a cover 1c attached to the top of the housing 1a so as to be openable and closable, a paper feed tray 1m, and a paper discharge tray 1n.

As shown in FIG. 3, inside the housing 1a, in addition to the image forming section 10, a transport mechanism 20, a platen 30, and a control section 90 are provided.

The image forming section 10 is a line-type head unit that is elongated in the paper width direction (direction perpendicular 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.

Each head 11 includes a flow path unit 11m and an actuator unit 11n, as shown in FIG.

A plurality of nozzles 11x are opened on the lower surface of the flow path unit 11m. A common flow path 11a communicating with an ink tank (not shown) and an individual flow path 11b for each nozzle 11x are formed inside the flow path unit 11m. The individual flow path 11b is a flow path from the outlet of the common flow path 11a to the nozzle 11x via the pressure chamber 11p. A plurality of pressure chambers 11p are open on the upper surface of the flow path unit 11m.

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

The diaphragm 11n1 and the plurality of individual electrodes 11n3 are electrically connected to the driver IC 11d. The driver IC 11d maintains the potential of the diaphragm 11n1 at the ground potential, while changing the potential of the individual electrode 11n3. Specifically, the driver IC 11d generates a drive signal based on the control signal from the control unit 90, and applies the drive signal to the individual electrode 11n3 via the signal line 11s. As a result, the potential of the individual electrode 11n3 changes between the predetermined drive potential and the ground potential. At this time, the portion (actuator 11n4) sandwiched between each individual electrode 11n3 and each pressure chamber 11p in the diaphragm 11n1 and the piezoelectric layer 11n2 deforms so as to be convex toward the pressure chamber 11p, thereby causing the pressure chamber The volume of the pressure chamber 11p changes, pressure is applied to the ink within the pressure chamber 11p, and the ink is ejected from the nozzle 11x. The actuator 11n4 is provided for each individual electrode 11n3, and can be deformed independently according to the potential applied to the individual 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 section 10 is arranged between the roller pair 21 and the roller pair 22 in the conveying direction (the vertical direction and the direction orthogonal to the paper width direction). When the conveyance motor 20m (see FIG. 7) is driven under the control of the control unit 90, the paper 100 placed on the paper feed tray 1m (see FIGS. 1 and 2) is sent out by the paper feed roller, and then The sheet is conveyed in the conveyance direction by the pair 21 and 22, and received in the sheet discharge tray 1n (see FIGS. 1 and 2).

As shown in FIGS. 5 and 6, the image reading section 50 includes a document table 60 formed by the upper part of the housing 1a, a reading unit 70 and a moving mechanism 80 arranged inside the housing 1a.

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 of paper 100 to be read is placed on the upper surface of the transparent plate 61. As shown in FIG.

The reading unit 70 includes a line sensor 71 and a carriage 72 that holds the line sensor 71. The carriage 72 can be reciprocated along a movement direction (in this embodiment, a direction parallel to the paper width direction shown in FIG. 3) by a movement mechanism 80.

The line sensor 71 extends in a direction perpendicular to the moving direction and the vertical direction. The line sensor 71 is a CIS (Contact Image Sensor) type (same-magnification optical system), and includes a plurality of light sources 71a each composed of light emitting diodes of three colors of RGB (red, green, blue), and a plurality of cylindrical, etc. It includes a magnifying lens 71b and a plurality of reading elements 71c. Each reading element 71c is composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor).

The cover 1c can be opened and closed with respect to the document table 60 as shown in FIGS. 1 and 2, and by closing the cover 1c, light from the outside is prevented 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 and 82b arranged with the transparent plate 61 in between in the moving direction, and a belt 83 wound around the pulleys 82a and 82b.

The carriage 72 is supported on the upper surface of the guide 81 and fixed to the upper end surface of the belt 83. Driven by the CIS moving motor 80m, the pulley 82a rotates and the belt 83 runs, so that the carriage 72 moves in the moving direction along the guide 81.

When reading the image of the paper 100 placed on the transparent plate 61, the control unit 90 controls the CIS movement motor 80m to move the carriage 72 in the movement direction. Further, at this time, the control unit 90 turns on the plurality of light sources 71a, and causes each of the plurality of light sources 71a to irradiate light toward the paper 100 placed on the transparent plate 61. The light passes through the transparent plate 61, is reflected by the paper 100, passes through the lens 71b, and enters the reading element 71c. The reading element 71c generates image read data (data indicating the amount of received light) by converting the received light into an electrical signal, and outputs the read data to the control unit 90.

The control unit 90 includes a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, and a RAM (Random Access Memory) 93, as shown in FIG. The ROM 92 stores programs and data for the CPU 91 to perform various controls. The RAM 93 temporarily stores data used when the CPU 91 executes a program. The CPU 91 executes processing according to programs and data stored in the ROM 92 and RAM 93, based on data input from an external device (such as a PC) or an input unit (switches and buttons provided on the housing 1a). do.

Further, as shown in FIG. 7, each head 11 is provided with six power supply circuits 11e1 to 11e6 electrically connected to the driver IC 11d. Each of the power supply circuits 11e1 to 11e6 may be, for example, a DC/DC converter made up of a plurality of electronic components such as an FET, an inductor, a resistor, and an electrolytic capacitor.

The control unit 90 outputs a voltage designation signal for designating the output voltage of each power supply circuit 11e1 to 11e6 to each power supply circuit 11e1 to 11e6. Each of the power supply circuits 11e1 to 11e6 outputs an output voltage designated by the voltage designation signal to the driver IC 11d. The voltages output by the six power supply circuits 11e1 to 11e6 are different from each other.

The driver IC 11d is connected to each of the plurality of individual electrodes 11n3 via a plurality of signal lines 11s (see FIGS. 4 and 7). Here, the control signal output from the control unit 90 to the driver IC 11d includes an assignment signal for assigning one of the six power supply circuits 11e1 to 11e6 to each actuator 11n4. The driver IC 11d generates a drive signal for each individual electrode 11n3 using the output voltage from the power supply circuit assigned according to the assignment signal, and applies the drive signal to each individual electrode 11n3 via the signal line 11s.

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

The control unit 90 may detect, for example, that the power of the multifunction device 1 has been switched from OFF to ON, that ink has been introduced from the ink tank to each head 11, that a predetermined period of time has passed since the most recent execution of the unevenness correction program, etc. Using this as a trigger, the unevenness correction program shown in FIG. 8 is executed.

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

In S1, the control unit 90 controls the driver IC 11d of each head 11 and the transport motor 20m, and causes the transport mechanism 20 to transport the paper 100 in the transport direction, while ejecting ink from the nozzle 11x of each head 11. As a result, ink dots are formed on the paper 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 paper 100 on which the inspection image has been formed is placed on the transparent plate 61 of the document table 60. For example, after the user moves the paper 100 on which the inspection image has been formed in step S1 and is received in the paper output tray 1n onto the transparent plate 61 of the document table 60, The controller 90 may issue an instruction via a switch or button, and use the instruction as a trigger to start S2. Alternatively, a mechanism provided in the multifunction device 1 moves the paper 100, on which the inspection image has been formed in step S1 and has been received in the paper output tray 1n, onto the transparent plate 61 of the document table 60, so that the paper 100 becomes transparent. The control unit 90 may start S2 using the placement on the plate 61 as a trigger.

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

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

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

After the unevenness correction program shown in FIG. 8, the control unit 90 executes the recording program shown in FIG. 9.

In the recording program, the control unit 90 first determines whether a recording command has been received (S11). The recording command is transmitted to the control unit 90 from an external device (such as a PC) or an input unit (switches and buttons provided on the housing 1a).

If a recording command has not been received (S11: NO), the control unit 90 repeats the process of S11.

If a recording command is received (S11: YES), the control unit 90 forms an image on the paper 100 based on the image data included in the recording command (S12: ejection process).

In S12 (discharging process), the control unit 90 controls the driver IC 11d of each head 11 and the transport motor 20m, and while transporting the paper 100 in the transport direction by the transport mechanism 20, ink is ejected from the nozzle 11x of each head 11. to be discharged. As a result, ink dots are formed on the paper 100, and an image is formed.

Further, in S12 (discharge process), the control unit 90 sends the driver IC 11d the assignment signal obtained in the unevenness correction program association step (S3) (for each actuator 11n4, the six power supply circuits 11e1 to 11e6). A control signal including a signal for allocating one of them is output. As a result, each actuator 11n4 is driven by the assigned power supply circuit among the six power supply circuits 11e1 to 11e6.

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

Next, with reference to FIGS. 10 and 11, the step (S3) of associating the unevenness correction program shown in FIG. 8 will be described.

In the matching step (S3), the control unit 90 first linearizes the concentration with respect to the voltage, as shown in FIG. 10 (S21). Specifically, the relationship between the voltage output to the driver IC 11d and the density of 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.

Note that the read data generated in S2 is RGB luminance data and can be converted to CMYK density data. The control unit 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 order of the density of ink ejected from the nozzle 11x by driving the actuators (S22: sorting process), based on the data corrected in S21. FIG. 11 shows an example in which a total of 1680 actuators 11n4 are sorted in order of concentration.

After S22 (sorting process), the control unit 90 sets the threshold T to the initial value Ti (S23). The initial value Ti is the 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 This is the value divided by the number of power supply circuits for which the number of actuators 11n4 does not reach the maximum number when allocated. 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 power supply circuit 11e1 to 11e6, and is stored in the ROM92. For example, if the total number of actuators 11n4 is 1680 and the maximum number determined for each power supply circuit 11e1 to 11e6 is 540, 540 actuators 11n4 are sequentially allocated to the first to third power supply circuits 11e1 to 11e3. Then, the number of remaining actuators 11n4 is 60 (less than 540), and the maximum number of actuators 11n4 cannot be assigned to the fourth to sixth power supply circuits 11e4 to 11e6. In this case, the number (x) of power supply circuits in 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 is stored in the ROM92.

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

After S24, the control unit 90 allocates a predetermined number of the actuators 11n4 sorted in order of density in S22 (sorting process) to the n-th power supply circuit in order from the actuator 11n4 with the lowest density (S25). The allocation data in S25 is stored in the RAM 93.

After S25, the control unit 90 determines whether the density difference has reached the threshold in the actuator 11n4 assigned to the n-th power supply circuit (S26: first determination step). The "concentration difference" is the difference between the maximum concentration value in the plurality of actuators 11n4 assigned to the n-th power supply circuit and the minimum concentration value in the plurality of actuators 11n4 assigned to the n-th power supply circuit.

If the concentration difference has not reached the threshold (S26: NO), the control unit 90 determines whether the number of actuators 11n4 assigned to the n-th power supply circuit has reached the maximum number (S27: second determination) step).

If the number of actuators 11n4 has not reached the maximum number (S27: NO), the control unit 90 determines whether all the actuators 11n4 have been assigned to the power supply circuits (S28).

If the assignment of all the actuators 11n4 to the power supply circuits has not been completed (S28: NO), the control unit 90 returns the process to S25, and assigns the actuators 11n4 for which the assignment to the power supply circuits has not been completed to a low concentration. A predetermined number of actuators are sequentially assigned to the n-th power supply circuit starting from the actuator 11n4.

If all the actuators 11n4 have been assigned to the power supply circuits (S28: YES), the control unit 90 ends the assignment of the actuators 11n4 to the n-th power supply circuit (S29), and advances the process to S33.

If the concentration difference reaches the threshold (S26: YES) or if the number of actuators 11n4 reaches the maximum number (S27: YES), the control unit 90 ends the assignment of the actuators 11n4 to the n-th power supply circuit. (S30), it is determined whether all the actuators 11n4 have been assigned to the power supply circuits (S31).

If the assignment of all the actuators 11n4 to the power supply circuits has not been completed (S31: NO), the control unit 90 sets n=n+1 (S32), returns the process to S25, and determines whether the assignment to the power supply circuits has been completed. A predetermined number of actuators 11n4 that are not available are assigned to the n-th power supply circuit in order from the actuator 11n4 with the lowest concentration.

If all the actuators 11n4 have been assigned to the power supply circuits (S31: YES), the control unit 90 advances the process to S33.

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

If n≧6 is not true (S33: NO), the control unit 90 sets the threshold value T=T×0.9 (S34), erases the allocation data stored in the RAM 93, and returns the process to S24. That is, if the actuator 11n4 is not assigned to any of the power supply circuits 11e1 to 11e6 (in other words, if any of the plurality of actuators 11n4 is not assigned to each of the six power supply circuits 11e1 to 11e6), the control unit 90 lowers the threshold T and executes the allocation process again (in other words, re-allocates the actuators 11n4 in order from the first power supply circuit 11e1). By lowering the threshold T and executing the assignment process again, the actuator 11n4 can be reliably assigned.

In the example of FIG. 11A, the maximum number (540) of actuators 11n4 are assigned to each of the first to third power supply circuits 11e1 to 11e3 (S27: YES → S30), and the maximum number of actuators 11n4 is assigned to the fourth power supply circuit 11e4. Actuators 11n4 less than the maximum number (50 pieces) are assigned (S26: YES → S30), less than the maximum number (10 pieces) of actuators 11n4 are assigned to the fifth power supply circuit 11e5 (S28: YES → S29), and the sixth power supply circuit Actuator 11n4 is not assigned to 11e6. In this case, the control unit 90 determines that n≧6 is not satisfied (S33: NO), sets the threshold value T=T×0.9 (S34), and reassigns the actuators 11n4 in order from the first power supply circuit 11e1.

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

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

In the example of FIG. 11(b), the maximum number (540) of actuators 11n4 is assigned to each of the first and second power supply circuits 11e1 and 11e2 (S27: YES→S30), and the third to fifth power supply circuits 11e3 Actuators 11n4 less than the maximum number (400, 190, 7) are assigned to each of the circuits 11e5 (S26: YES → S30), and actuators 11n4 less than the maximum number (3) are assigned 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).

When n=6 (S35: YES), the control unit 90 controls a specific circuit (a "specific circuit" is a power supply circuit in which the number of actuators 11n4 has not reached the maximum number) among the six power supply circuits 11e1 to 11e6. ) is equal to or less than a predetermined value (S36: determination process).

When there are multiple specific circuits, the "predetermined value" is a value based on the average value of concentration differences in the multiple specific circuits (for example, the above average value derived from the read data generated in S2 and the value stored in the ROM 92). and a fixed value α).

For example, in the example of FIG. 11(b), there are four specific circuits (third to sixth power supply circuits), and the concentration difference among the plurality of actuators 11n4 assigned to the third power supply circuit is 11D (D: concentration unit), The concentration difference among the plurality of actuators 11n4 assigned to the fourth power supply circuit is 10D, the concentration difference among the plurality of actuators 11n4 assigned to the fifth power supply circuit is 9D, and the concentration difference among the plurality of actuators 11n4 assigned to the sixth power supply circuit. Assume that the difference is 10D. In this case, the average value of the concentration differences in the four specific circuits is 10D, and if the fixed value α=0.5D, then the concentration difference (11D) of the first power supply circuit is the predetermined value (average value + fixed value α=10 .5D) or less (S36: NO).

When there are multiple specific circuits, if the density difference in at least one of the multiple specific circuits is not equal to or less than the predetermined value (S36: NO), the control unit 90 returns the process to S34. That is, in this case, the control unit 90 sets the threshold value T=T×0.9 (S34), erases the allocation data stored in the RAM 93, and executes the allocation process again (in other words, the first power supply circuit 11e1 (The actuators 11n4 are reassigned in order from the start).

For example, in the example of FIG. 11(b), it is determined that the concentration difference in the first power supply circuit is not equal to or less than the predetermined value as described above (S36: NO), and the allocation process (S24 to S34) sets the threshold value T=T×0.9. ) is executed again and the correspondence shown in FIG. 11(c) is obtained. In the example of FIG. 11(c), there are four specific circuits (third to sixth power supply circuits), and the concentration difference among the plurality of actuators 11n4 assigned to the third power supply circuit is 10.1D (D: concentration unit). , 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 10.1D. Assume that the density difference in the actuator 11n4 is 10D. In this case, the average value of the concentration difference in the four specific circuits is 10D, and if the fixed value α=0.5D, the concentration difference of all the specific circuits (third to sixth power supply circuits) is a predetermined value (average value + fixed value α=10.5D) or less (S36: YES).

If the density differences of all the specific circuits are less than or equal to the predetermined value (S36: YES), the control unit 90 determines whether the threshold T is less than the lower limit Tx (S37).

If the threshold value T is not less than the lower limit value Tx (S37: NO), the control unit 90 maintains the correspondence between the power supply circuits 11e1 to 11e6 and the actuator 11n4 stored in the RAM 93 at the time of determination in S37, and executes the process. Return to S34. In other words, in this case, the control unit 90 creates and stores data regarding yet another correspondence while retaining the data regarding the correspondence obtained through the current allocation process (S24 to S34).

If the threshold value T is less than the lower limit value Tx (S37: YES), the control unit 90 determines the correspondence relationship stored in the RAM 93 (the power supply circuit including the specific circuit whose density difference was determined to be less than or equal to the predetermined value in S36). 11e1 to 11e6 and the actuators 11n4) is determined (S38).

If there are a plurality of correspondence relationships (S38: YES), the control unit 90 stores in the RAM 93 the correspondence relationship with the smallest average value of concentration differences in the six power supply circuits 11e1 to 11e6 among the plurality of correspondence relationships, and stores the correspondence relationship in the RAM 93 that The correspondence relationship is deleted from the RAM 93 (S39).

For example, in the example of FIG. 11(c), it is determined that the threshold value T is not less than the lower limit value Tx (S37: NO), and the allocation process (S24 to S34) is executed again with the threshold value T=T×0.9. 11(d) is obtained. In the example of FIG. 11(d), if it is determined that the threshold value T is less than the lower limit value Tx (S37: YES), the correspondence relationship stored in the RAM 93 at this point is as shown in FIG. 11(c) and FIG. (d), and it is determined that there are a plurality of correspondence relationships stored in the RAM 93 (S38: YES). In this case, among the correspondence relationships shown in FIGS. 11(c) and 11(d), one correspondence relationship in which the average value of concentration differences in the six power supply circuits 11e1 to 11e6 is small is held in the RAM 93, and the other correspondence relationship is held in the RAM 93. The relationship is deleted from RAM 93.

In the example of FIG. 11(e), in addition to the first to sixth power supply circuits 11e1 to 11e6, the actuator 11n4 is also assigned to a seventh power supply circuit that is not included in the head 11. In the example of FIG. 11(e), it is determined that the density difference of the specific circuit is not less than the predetermined value (S36: NO) and the allocation process (S24 to S34) is executed again, resulting in 90 out of the total 1680 This corresponds to the case where the actuator 11n4 is not assigned to any of the six power supply circuits 11e1 to 11e6. In this case, the control unit 90 determines that n is not 6 (S35: NO), and holds in the RAM 93 the correspondence between the power supply circuits 11e1 to 11e6 and the actuator 11n4, which are the targets of the most recent S36 (determination process), The correspondence shown in FIG. 11(e) (that is, the correspondence when n>6) is deleted from the RAM 93 (S40).

After S39, if there is not a plurality of correspondences (S38: NO), or after S40, the control unit 90 ends the routine.

The control unit 90 executes S12 (discharge process) in the recording program (FIG. 9) based on the correspondence relationship stored in the RAM 93 in the correspondence step (S3).

As described above, according to the present embodiment, as shown in FIG. 10, when the control unit 90 determines that the density difference of the specific circuit is not equal to or less than the predetermined value (S36: NO), the control unit 90 performs the allocation process (S24). -S34) are executed again. Thereby, density differences among the plurality of actuators 11n4 assigned to each of the power supply circuits 11e1 to 11e6 can be suppressed, and unevenness correction can be performed appropriately.

Further, according to the present embodiment, the process can be simplified by performing S36 (determination process) not for all the power supply circuits 11e1 to 11e6 but for a specific circuit in which the number of actuators 11n4 has not reached the maximum number.

When there are a plurality of specific circuits, the control unit 90 re-executes the allocation process (S24 to S34) when it is determined that the concentration difference in at least one of the plurality of specific circuits is not equal to or less than a predetermined value (S36: NO). . In this case, the above effect (the effect of suppressing density differences among the plurality of actuators 11n4 assigned to each power supply circuit 11e1 to 11e6 and appropriately performing unevenness correction) can be obtained more reliably.

If there are multiple correspondences between the actuator 11n4 and the power supply circuits 11e1 to 11e6 including the specific circuit for which the concentration difference is determined to be less than or equal to the predetermined value (S36: YES), the control unit 90 controls the Among the correspondence relationships, S12 (discharge process) is executed based on the correspondence relationship in which the average value of density differences in the six power supply circuits 11e1 to 11e6 is the smallest (S39). In this case, the above effect (the effect of suppressing density differences among the plurality of actuators 11n4 assigned to each power supply circuit 11e1 to 11e6 and appropriately performing unevenness correction) can be obtained more reliably.

The control unit 90 executes S22 (sorting process) before the allocation process (S24 to S34), and assigns the actuator 11n4 to one of the six power supply circuits 11e1 to 11e6 in the order sorted in S22 (sorting process). (S25), and it is determined whether the concentration difference has reached the threshold value in the power supply circuit (S26: first determination step). If it is determined that the concentration difference has not reached the threshold (S26: NO), the control unit 90 determines whether the number of actuators 11n4 assigned to the power supply circuit has reached the maximum number (S27). : second judgment step), if it is judged that the number of actuators 11n4 has not reached the maximum number (S27: NO), S26 (first judgment step) is executed again for the power supply circuit. When it is determined that the concentration difference has reached the threshold value (S26: YES) or when it is determined that the number of actuators 11n4 has reached the maximum number (S27: YES), the control unit 90 controls the power supply circuit. (S30), and among the six power supply circuits 11e1 to 11e6, the assignment of the actuator 11n4 to another power supply circuit is completed (S32), and among the plurality of actuators 11n4, the assignment has not been completed. , S26 (first judgment step) is executed. In this case, the allocation process (S24 to S34) can be efficiently executed.

It is determined that the density difference of the specific circuit is not less than the predetermined value (S36: NO), and the allocation process (S24 to S34) is executed again, and by executing S26 (first determination step) and S27 (second determination step), There is a case where one of the plurality of actuators 11n4 is not assigned to one of the six power supply circuits 11e1 to 11e6 (S35: NO, see FIG. 11(e)). In this case, the control unit 90 executes S12 (discharge process) based on the correspondence between the power supply circuits 11e1 to 11e6 and the actuator 11n4, which are the targets of the most recent S36 (determination process) (S40). In this case, while ensuring the assignment of the actuators 11n4, it is possible to obtain (the effect of suppressing density differences among the plurality of actuators 11n4 assigned to each of the power supply circuits 11e1 to 11e6 and appropriately performing unevenness correction). .

In the allocation process (S24 to S34), the control unit 90 assigns one of the plurality of actuators 11n4 to each of the six power supply circuits 11e1 to 11e6 by executing S26 (first determination step) and S27 (second determination step). is not allocated (S33: NO), the threshold T is lowered (S34), and the allocation process (S24 to S34) is executed again. In this case, the actuator 11n4 can be reliably assigned.

If the control unit 90 determines that the density difference of the specific circuit is not less than the predetermined value (S36: NO), it lowers the threshold T (S34) and executes the allocation process (S24 to S34) again. In this case, the actuator 11n4 can be reliably assigned.

The initial value Ti of the threshold T is calculated by subtracting the minimum density Dmin of the plurality of actuators 11n4 from the maximum density Dmax of the plurality of actuators 11n4 by This is the value divided by the number of power supply circuits for which the number of actuators 11n4 does not reach the maximum number if the number of actuators 11n4 is allocated until reaching the maximum number. In this case, the allocation 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 the average value of density differences in the plurality of specific circuits. In this case, S36 (judgment process) can be executed efficiently, and the above effect (the effect of suppressing density differences among the plurality of actuators 11n4 assigned to each power supply circuit 11e1 to 11e6 and appropriately performing unevenness correction) can be obtained more reliably.

<Modified example>
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made within the scope of the claims.

For example, in the above-described embodiment, the assignment is performed in order from the actuators with the lowest concentration, but the assignment may be performed in the order from the actuator with the highest concentration. In addition, by assigning the actuators sorted in order of concentration in order of decreasing concentration change (in the example of FIG. 11, the one with the lowest concentration), the maximum number is reached without the concentration difference reaching the threshold value in the first half of the stage. The allocation process can be executed efficiently.

In the case where there are multiple specific circuits, in the embodiment described above, when it is determined that the density difference in at least one of the multiple specific circuits is not equal to or less than the predetermined value (S36: NO), the allocation process is executed again. However, the allocation process may be executed again when it is determined that the density difference is not less than or equal to the predetermined value in all the specific circuits (S36: NO).

The predetermined value is limited to a value based on the average value of concentration 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). Instead, it may be a fixed value β stored in the ROM 92.

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

When lowering the threshold value, the threshold value is multiplied by 0.9 in the above-described embodiment, but the invention is not limited to this. For example, the threshold value may be multiplied by any decimal number other than 0.9, divided by any number greater than 1, or subtracted by any positive number. Furthermore, the amount of decrease in the threshold value may be made different between the first S34 and the second S34.

The actuator is not limited to the piezoelectric type, and may be of other types (for example, a thermal type using a heating element, an electrostatic type using electrostatic force, etc.).

Although the head is of a line type in the above-described embodiment, it may be of a serial type.

The head may eject a liquid other than ink (for example, a processing liquid that aggregates or precipitates components in the ink).

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

The liquid ejecting device according to the present invention is not limited to a multifunction device (that is, it may be a device having an image forming section but not having an image reading section). The present invention is also applicable to printers, facsimile machines, copiers, etc. Further, the present invention is also applicable to liquid ejecting devices used for purposes other than image recording (for example, liquid ejecting devices that eject conductive liquid onto a substrate to form a conductive pattern).

The inspection image is read (S2) by a device other than the liquid ejection device according to the present invention, and then the liquid ejection device according to the present invention performs a matching step (S2) based on the read data received from the other device. S3) may also be executed. For example, the inspection image may be read (S2) using a spectrophotometer (such as "SpectroEye" manufactured by X-Rite). In this case, the liquid ejection device according to the present invention may execute the matching step (S3) based on the read data received from the spectrophotometer.

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

According to a reference example of the present invention, "different voltages are output to a plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and an assigned actuator among the plurality of actuators. a plurality of power supply circuits, and a control unit, the control unit configured to control the actuator so that a difference in concentration of liquid ejected from the nozzle is equal to or less than a predetermined value in the actuator assigned to each of the plurality of power supply circuits. The method is characterized in that an assignment process is executed in which each of the plurality of actuators is assigned to one of the plurality of power supply circuits, and one of the plurality of actuators is assigned to each of the plurality of power supply circuits. A liquid ejecting device that outputs a plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and a plurality of actuators that output different voltages to assigned actuators among the plurality of actuators. A control method for controlling a liquid ejecting device comprising a power supply circuit, wherein the actuator assigned to each of the plurality of power supply circuits maintains a difference in concentration of liquid ejected from the nozzle to a predetermined value or less. The present invention is characterized in that an assignment process is executed in which each of the plurality of actuators is assigned to one of the plurality of power supply circuits, and one of the plurality of actuators is assigned to each of the plurality of power supply circuits. A control method that outputs different voltages to a plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and an assigned actuator among the plurality of actuators. a plurality of power supply circuits, the liquid ejection device comprising: a plurality of power supply circuits; A program that functions as an allocation means for allocating each of a plurality of actuators to one of the plurality of power supply circuits, and allocating one of the plurality of actuators to each of the plurality of power supply circuits. is provided. In this reference example, S36 (determination processing) is not limited to being performed for a specific circuit in which the number of actuators 11n4 has not reached the maximum number, but may be performed for all power supply circuits 11e1 to 11e6.

1 Multifunction machine (liquid discharge device)
10 Image forming unit 11e1 to 11e6 Power supply circuit 11n4 Actuator 11x Nozzle 90 Control unit

Claims (11)

multiple nozzles;
a plurality of actuators provided for each of the plurality of nozzles;
a plurality of power supply circuits that output mutually different voltages to assigned actuators among the plurality of actuators;
comprising a control unit;
The control unit includes:
an assignment process of assigning one of the plurality of actuators to each of the plurality of power supply circuits;
performing a discharge process of driving the plurality of actuators by each of the plurality of power supply circuits assigned in the assignment process and causing liquid to be discharged from the plurality of nozzles;
After the allocation process and before the discharge process,
Among the plurality of power supply circuits, in a specific circuit that is a power supply circuit in which the number of actuators does not reach the maximum number determined for the power supply circuit, the maximum concentration of the liquid discharged from the nozzle and the Executing a determination process to determine whether a concentration difference, which is a difference from a minimum value of the concentration of the liquid ejected from the nozzle, is less than or equal to a predetermined value;
The liquid ejecting apparatus is characterized in that when it is determined in the determination process that the concentration difference of the specific circuit is not equal to or less than the predetermined value, the allocation process is executed again. The control unit includes:
When there are a plurality of specific circuits, the allocation process is executed again when it is determined in the determination process that the density difference is not equal to or less than the predetermined value in at least one of the plurality of specific circuits. The liquid ejection device according to claim 1. The control unit includes:
If there are a plurality of correspondences between the plurality of power supply circuits and the plurality of actuators including the specific circuit for which the density difference was determined to be less than or equal to the predetermined value in the determination process,
Liquid ejection according to claim 1 or 2, characterized in that the ejection process is executed based on the correspondence relationship in which the average value of the concentration difference in the plurality of power supply circuits is the smallest among the plurality of correspondence relationships. Device. The control unit includes:
Before the allocation process, performing a sorting process in which the plurality of actuators are sorted in order of the concentration of the liquid ejected from the nozzle by driving the actuator,
In the allocation process,
A first determination 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 the concentration difference has reached a threshold value in the power supply circuit. step and
If it is determined in the first determination step that the concentration difference has not reached the threshold, a second determination is made to determine whether the number of actuators assigned to the power supply circuit has reached the maximum number. Run the steps and
If it is determined in the second determination step that the number of actuators has not reached the maximum number, re-executing the first determination step for the power supply circuit;
If it is determined in the first determination step that the concentration difference has reached the threshold value, or if it is determined in the second determination step that the number of actuators has reached the maximum number, Finishing the assignment of the actuators, and performing the first determination step for a power supply circuit different from the power supply circuit among the plurality of power supply circuits and for an actuator for which assignment has not been completed among the plurality of actuators. The liquid ejection device according to any one of claims 1 to 3, characterized in that: The control unit includes:
If it is determined in the determination process that the concentration difference of the specific circuit is not equal to or less than the predetermined value and the allocation process is executed again, the first determination step and the second determination step are performed to determine whether the plurality of actuators If any one of the power supply circuits cannot be assigned to any of the plurality of power supply circuits,
5. The liquid ejecting apparatus according to claim 4, wherein the ejecting process is executed based on a correspondence relationship between the plurality of power supply circuits and the plurality of actuators, which are targets of the most recent determination process. The control unit includes:
In the allocation process, when any of the plurality of actuators is not allocated to each of the plurality of power supply circuits by executing the first judgment step and the second judgment step,
6. The liquid ejecting apparatus according to claim 4, wherein the threshold value is lowered and the allocation process is executed again. The control unit includes:
If 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 threshold value is lowered and the allocation process is executed again. The liquid ejection device according to item 1. The initial value of the threshold value is a value obtained by subtracting the minimum concentration in the plurality of actuators from the maximum concentration in the plurality of actuators, and the plurality of actuators are sequentially assigned to each of the plurality of power supply circuits until the maximum number is reached. 8. The liquid ejecting device according to claim 6, wherein the value is divided by the number of power supply circuits in which the number of actuators does not reach the maximum number when the number of actuators reaches the maximum number. The liquid according to any one of claims 1 to 8, wherein the predetermined value is a value based on an average value of the concentration difference in the plurality of specific circuits when there are a plurality of the specific circuits. Discharge device. 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 different voltages to assigned actuators among the plurality of actuators. A control method for controlling a liquid ejection device, the method comprising:
an assignment process of assigning one of the plurality of actuators to each of the plurality of power supply circuits;
performing a discharge process of driving the plurality of actuators by each of the plurality of power supply circuits assigned in the assignment process and causing liquid to be discharged from the plurality of nozzles;
After the allocation process and before the discharge process,
Among the plurality of power supply circuits, in a specific circuit that is a power supply circuit in which the number of actuators does not reach the maximum number determined for the power supply circuit, the maximum concentration of the liquid discharged from the nozzle and the Executing a determination process to determine whether a concentration difference, which is a difference from a minimum value of the concentration of the liquid ejected from the nozzle, is less than or equal to a predetermined value;
A control method characterized in that, if 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 allocation process is executed again. 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 different voltages to assigned actuators among the plurality of actuators. liquid ejection device,
Allocating means for allocating one of the plurality of actuators to each of the plurality of power supply circuits;
Discharge means for driving the plurality of actuators by each of the plurality of power supply circuits assigned by the assignment means, and discharging liquid from the plurality of nozzles;
After the assignment by the assignment means and before the discharge by the discharge means,
Among the plurality of power supply circuits, in a specific circuit that is a power supply circuit in which the number of actuators does not reach the maximum number determined for the power supply circuit, the maximum concentration of the liquid discharged from the nozzle and the A program that functions as a determination means for determining whether a concentration difference between a minimum value of the concentration of liquid ejected from a nozzle is less than or equal to a predetermined value,
A program characterized in that, when the determining means determines that the density difference of the specific circuit is not equal to or less than the predetermined value, the allocating means executes the allocation again.

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