JP2021030500A - Liquid discharge device, method for control thereof and program - Google Patents

Abstract

To make it possible to adequately perform unevenness correction by suppressing density difference in a plurality of actuators which are allocated to each power supply circuit.SOLUTION: A control part executes allocation processing (S24 to S34) for allocating any one of actuators to each power supply circuit, and discharge processing for driving the actuator by the power supply circuit allocated in the allocation processing and discharges a liquid from a nozzle. Further, the control part determines, after the allocation processing (S24 to S34) and before the discharge processing, 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 a density of the liquid discharged from the nozzle, is a specified value or less in a specific circuit which is the power supply circuit of the plurality of power supply circuits in which the number of actuators does not reach a maximum number determined for the power supply circuit (S36), and when it is determined that the density difference in the specific circuit is not the specified value or less (S36: NO), the control part executes the allocation processing (S24 to S34) again.SELECTED DRAWING: Figure 10

Description

The present invention relates to a liquid discharge device including a plurality of actuators and a plurality of power supply circuits, a control method and a program thereof.

Patent Document 1 shows that, in performing unevenness correction (correction of variation in discharge 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.

JP-A-2019-064151

In Patent Document 1, the density difference between a plurality of actuators assigned to each power supply circuit is not taken into consideration, and when the density difference is large, unevenness correction cannot be appropriately performed even if a different voltage is output for each power supply circuit. Problems can arise.

An object of the present invention is to provide a liquid discharge device, a control method and a program thereof, which can suppress a concentration difference in a plurality of actuators assigned to each power supply circuit and can appropriately correct unevenness.

According to the 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 actuator assigned to the plurality of actuators. A plurality of power supply circuits and a control unit are provided, and the control unit allocates one of the plurality of actuators to each of the plurality of power supply circuits. The plurality of actuators are driven by each of the power supply circuits to discharge the liquid from the plurality of nozzles, and the discharge process is executed. After the allocation process and before the discharge process, the plurality of power supplies are used. Among the circuits, in a specific circuit which is a power supply circuit in which the number of the actuators does not reach the maximum number defined for the power supply circuit, the maximum value of the concentration of the liquid discharged from the nozzle and the discharge from the nozzle. A determination process is executed to determine whether or not the concentration difference, which is the difference from the minimum value of the concentration of the liquid, is equal to or less than the predetermined value, and the concentration difference of the specific circuit is not equal to or less than the predetermined value in the determination process. If determined, a liquid discharge device is provided, characterized in that the allocation process is performed again.

According to the second 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 actuator assigned to the plurality of actuators. A control method for controlling a liquid discharge device including a plurality of power supply circuits, wherein any of the plurality of actuators is assigned to each of the plurality of power supply circuits, and the allocation process is assigned by the allocation process. The plurality of actuators are driven by each of the plurality of power supply circuits to discharge the liquid from the plurality of nozzles, and the discharge process is executed, after the allocation process and before the discharge process. Among the plurality of power supply circuits, in a specific circuit which is a power supply circuit in which the number of actuators does not reach the maximum number defined for the power supply circuit, the maximum value of the concentration of the liquid discharged from the nozzle and the said. A determination process is executed to determine whether or not the concentration difference, which is the difference from the minimum value of the concentration of the liquid discharged from the nozzle, is equal to or less than a predetermined value, and in the determination process, the concentration difference of the specific circuit is the predetermined value. If it is determined that the value is not less than or equal to the value, a control method is provided, which comprises executing the allocation process again.

According to the third 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 actuator assigned to the plurality of actuators. A liquid discharge device including a plurality of power supply circuits for assigning any of the plurality of actuators to each of the plurality of power supply circuits, an allocation means, and each of the plurality of power supply circuits allocated by the allocation means. Of the plurality of power supply circuits, the discharge means for driving the plurality of actuators and discharging the liquid from the plurality of nozzles, and after the allocation by the allocation means and before the discharge by the discharge means. In a specific circuit, which is a power supply circuit in which the number of actuators does not reach the maximum number specified for the power supply circuit, the maximum value of the concentration of the liquid discharged from the nozzle and the liquid discharged from the nozzle. A program that functions as a determination means for determining whether or not the concentration difference, which is the difference from the minimum concentration value, is equal to or less than a predetermined value, and the determination means causes the concentration difference of the specific circuit to be equal to or less than the predetermined value. If it is determined that this is not the case, a program is provided, characterized in that the allocation means executes the allocation again.

According to the first to third viewpoints, the density difference in the 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 the specific circuits, the control unit re-executes the allocation process when it is determined in the determination process that the concentration difference is not equal to or less than the predetermined value in at least one of the plurality of specific circuits. You can do it. In this case, the above effect (the effect of suppressing the density difference in the plurality of actuators assigned to each power supply circuit and appropriately performing unevenness correction) can be obtained more reliably.

When the control unit has a plurality of correspondences between the plurality of power supply circuits 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 and the plurality of actuators, the plurality of control units may be used. Among the correspondence relationships, the discharge process may be executed based on the correspondence relationship in which the average value of the concentration differences in the plurality of power supply circuits is the smallest. In this case, the above effect (the effect of suppressing the density difference in the plurality of actuators assigned to each power supply circuit and appropriately performing unevenness correction) can be obtained more reliably.

Prior to the allocation process, the control unit executes a sort process in which the plurality of actuators are sorted in order of the concentration of the liquid discharged from the nozzle by driving the actuator, and in the allocation process, the plurality of actuators are sorted. The first determination step, in which the actuators are assigned to one of the plurality of power supply circuits in the order sorted by the sorting process, and whether or not the concentration difference reaches the threshold value in the power supply circuit is determined. When it is determined in the first determination step that the concentration difference has not reached the threshold value, it is determined whether or not the number of the 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 is executed. When it is determined that the concentration difference has reached the threshold value, or when it is determined that the number of the actuators has reached the maximum number in the second determination step, the actuators are assigned to the power supply circuit. The first determination step may be executed for a power supply circuit that is finished and is different from the power supply circuit among the plurality of power supply circuits, and for an actuator that has not been assigned among the plurality of actuators. In this case, the allocation process can be executed efficiently.

When the control unit determines in the determination process that the concentration difference of the specific circuit is not equal to or less than the predetermined value and executes the allocation process again, the control unit executes the first determination step and the second determination step. When any one of the plurality of actuators is not assigned to any of the plurality of power supply circuits, based on the correspondence relationship between the plurality of power supply circuits and the plurality of actuators which are the targets of the latest determination processing. The discharge process may be executed. In this case, it is possible to obtain the above effect (the effect of suppressing the density difference in the plurality of actuators assigned to each power supply circuit and appropriately performing unevenness correction) while reliably allocating the actuators.

When any of the plurality of actuators is not assigned to each of the plurality of power supply circuits by executing the first determination step and the second determination step in the allocation process, the control unit sets the threshold value. It may be lowered and the allocation process may be executed again. In this case, the actuator can be reliably assigned.

When the control unit determines in the determination process that the concentration difference of the specific circuit is not equal to or less than the predetermined value, the control unit may lower the threshold value and re-execute the allocation process. In this case, the actuator can be reliably assigned.

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 until 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 number of actuators may be the value divided by the number of power supply circuits that do not reach the maximum number. In this case, the allocation process can be executed efficiently.

When there are a plurality of the specific circuits, the predetermined value may be a value based on the average value of the concentration 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 the density difference in the plurality of actuators assigned to each power supply circuit and appropriately correcting the unevenness) can be obtained more reliably. it can.

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

It is a perspective view which shows the multifunction device which concerns on one Embodiment of this invention. It is a perspective view which shows the state which the cover is closed in the multifunction device of FIG. It is a top view which shows the inside of the housing of the multifunction device of FIG. It is a partial cross-sectional view of the head shown in FIG. It is a top view which shows the upper part of the housing of the multifunction device of FIG. It is a side view which shows the upper part of the housing of the multifunction device of FIG. It is a block diagram which shows the electric structure of the multifunction device of FIG. It is a flow chart which shows the unevenness correction program executed by the control part of the multifunction device of FIG. It is a flow chart which shows the recording program executed by the control part of the multifunction device of FIG. It is a flow chart which shows the process which is executed in the association step of the unevenness correction program. It is explanatory drawing which shows the example which sequentially assigns the actuator sorted in order of concentration to each power supply circuit.

As shown in FIGS. 1 and 2, the multifunction device 1 according to the 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 is provided with a flatbed type image reading unit 50 provided at the upper part, a cover 1c removably attached to the upper part of the housing 1a, a paper feed tray 1 m, and a paper output tray 1n.

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

The image forming unit 10 is a line-type head unit that is long in the paper width direction (direction orthogonal to the vertical direction) and includes four heads 11. Each of the four heads 11 has a plurality of nozzles 11x and is arranged in a staggered pattern in the paper width direction.

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

A plurality of nozzles 11x are opened on the lower surface of the flow path unit 11m. Inside 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. 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 opened on the upper surface of the flow path unit 11m.

The actuator unit 11n is composed of a metal diaphragm 11n1 arranged on the upper surface of the flow path unit 11m so as to cover a 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 so as to face each of the plurality of pressure chambers 11p on the upper surface.

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 electrodes 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 electrodes 11n3 via the signal line 11s. As a result, the potential of the individual electrodes 11n3 changes between the predetermined drive potential and the ground potential. At this time, the portion (actuator 11n4) sandwiched between the individual electrodes 11n3 and each pressure chamber 11p in the diaphragm 11n1 and the piezoelectric layer 11n2 is deformed so as to be convex toward the pressure chamber 11p, so that the pressure chamber is formed. The volume of 11p changes, pressure is applied to the ink in 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 independently deformed according to the potential applied to the individual electrode 11n3.

The transport mechanism 20 has a paper feed roller (not shown) and two roller pairs 21 and 22 (see FIG. 3). An image forming portion 10 is arranged between the roller pair 21 and the roller pair 22 in the transport direction (direction orthogonal to the vertical direction and the paper width direction). When the transport motor 20 m (see FIG. 7) is driven by the control of the control unit 90, the paper 100 arranged in the paper feed tray 1 m (see FIGS. 1 and 2) is fed by the paper feed roller and then the rollers. It is conveyed in the transport direction by pairs 21 and 22, and is received by the output tray 1n (see FIGS. 1 and 2).

As shown in FIGS. 5 and 6, the image reading unit 50 includes a document base 60 composed of an upper portion of the housing 1a, a reading unit 70 arranged in the housing 1a, and a moving mechanism 80.

A translucent plate 61 made of plastic, glass, or the like is fitted in the platen 60. As shown in FIG. 6, the paper 100 to be read is placed on the upper surface of the translucent 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 along a moving direction (in this embodiment, a direction parallel to the paper width direction shown in FIG. 3) by the 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) method (equal magnification optical system), and has a plurality of light sources 71a each composed of light emitting diodes of three colors of RGB (red, green, blue), a plurality of tubular shapes, and the like. It includes a magnification lens 71b and a plurality of reading elements 71c. Each reading element 71c is composed of, for example, CMOS (Complementary Metal Oxide Semiconductor).

As shown in FIGS. 1 and 2, the cover 1c can be opened and closed with respect to the platen 60, and by closing the cover 1c, light from the outside is suppressed 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 so as to sandwich the light transmitting plate 61 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. The pulley 82a is rotated by driving the CIS moving motor 80m, and the belt 83 travels, 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 translucent plate 61, the control unit 90 controls the CIS moving motor 80m to move the carriage 72 in the moving direction. At this time, the control unit 90 turns on the plurality of light sources 71a and irradiates the paper 100 placed on the translucent plate 61 with light from each of the plurality of light sources 71a. The light passes through the translucent plate 61, is reflected by the paper 100, 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 image reading data (data indicating the amount of received light), and outputs the reading 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 ROM 92 stores programs and data for the CPU 91 to perform various controls. The RAM 93 temporarily stores data used by the CPU 91 when executing a program. The CPU 91 executes processing according to the programs and data stored in the ROM 92 and the RAM 93 based on the data input from the external device (PC or the like) or the input unit (switches and buttons provided in the housing 1a). To 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 power supply circuit 11e1 to 11e6 may be, for example, a DC / DC converter composed of 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 power supply circuit 11e1 to 11e6 to each power supply circuit 11e1 to 11e6. Each power supply circuit 11e1 to 11e6 outputs the output voltage specified 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 the 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 allocation signal for allocating 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 by the output voltage from the power supply circuit assigned according to the assigned 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 has, for example, that the power supply of the multifunction device 1 has been switched from OFF to ON, that ink has been introduced into each head 11 from the ink tank, that a predetermined time has passed since the latest unevenness correction program was executed, and the like. Is used as a trigger to execute the unevenness correction program shown in FIG.

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 transfer motor 20 m, and while the transfer mechanism 20 conveys the paper 100 in the transfer direction, ink is ejected from the nozzles 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 is formed is placed on the translucent plate 61 of the platen 60. For example, after the user moves the paper 100 on which the inspection image is formed by S1 and received in the output tray 1n onto the translucent plate 61 of the platen 60, it is provided in the input unit (housing 1a). The control unit 90 may start S2 by giving an instruction via a switch or a button) and using the instruction as a trigger. Alternatively, a mechanism provided in the multifunction device 1 moves the paper 100 on which the inspection image is formed by S1 and received in the output tray 1n onto the translucent plate 61 of the platen 60, and the paper 100 transmits light. The control unit 90 may start S2 with the placement on the plate 61 as a trigger.

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 indicates the read data (light receiving amount) of the inspection image. Data) is generated by the reading element 71c.

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

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

The control unit 90 executes the recording program shown in FIG. 9 after the unevenness correction program shown in FIG.

In the recording program, the control unit 90 first determines whether or not a recording command has been received (S11). The recording command is transmitted to the control unit 90 from an external device (PC or the like) or an input unit (switches or buttons provided in the housing 1a).

When the recording command is not received (S11: NO), the control unit 90 repeats the process of S11.

When the 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 (discharge processing), the control unit 90 controls the driver IC 11d of each head 11 and the transfer motor 20 m, and while the transfer mechanism 20 conveys the paper 100 in the transfer direction, ink is introduced from the nozzle 11x of each head 11. Is discharged. As a result, ink dots are formed on the paper 100, and an image is formed.

Further, in S12 (discharge processing), the control unit 90 sends the driver IC 11d the allocation signal (six power supply circuits 11e1 to 11e6 for each actuator 11n4) obtained in the association step (S3) of the unevenness correction program. A control signal including a signal for assigning 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 processing), the control unit 90 ends the recording program.

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

In the association step (S3), the control unit 90 first performs linearization with respect to the voltage of the concentration as shown in FIG. 10 (S21). Specifically, the relationship between the voltage output to the driver IC 11d 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 non-linear. 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 can be converted into CMYK density data. The control unit 90 converts the read data generated in S2 into CMYK density data, and then performs the processing in S21.

After S21, the control unit 90 sorts the plurality of actuators 11n4 in order of the density of the ink ejected from the nozzles 11x by driving the actuators based on the data corrected in S21 (S22: sorting process). 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 value T to the initial value Ti (S23). The initial value Ti is the value obtained by subtracting the minimum concentration Dmin in the plurality of actuators 11n4 from the maximum concentration Dmax in the plurality of actuators 11n4 until x (the plurality of actuators 11n4 reach the maximum number sequentially in the six power supply circuits 11e1 to 11e6). It is a value divided by the number of power supply circuits in which the number of actuators 11n4 does not reach the maximum number when assigned. 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 ROM 92. For example, when the total number of actuators 11n4 is 1680 and the maximum number defined for each power supply circuit 11e1 to 11e6 is 540, 540 actuators 11n4 are sequentially assigned to the first to third power supply circuits 11e1 to 11e3. Then, the number of the 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 the power supply circuits in which the number of actuators 11n4 does not reach the maximum number is “3”. As described above, 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 ROM 92.

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

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

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

When the concentration difference does not reach the threshold value (S26: NO), the control unit 90 determines whether or not the number of actuators 11n4 assigned to the nth power supply circuit has reached the maximum number (S27: second determination). Step).

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

When all the actuators 11n4 have not been assigned to the power supply circuit (S28: NO), the control unit 90 returns the process to S25, and the actuator 11n4 whose assignment to the power supply circuit has not been completed has a low concentration. A predetermined number of actuators 11n4 are assigned to the nth power supply circuit in this order.

When the allocation of all the actuators 11n4 to the power supply circuit is completed (S28: YES), the control unit 90 ends the allocation of the actuator 11n4 to the nth power supply circuit (S29), and proceeds to the process in S33.

When the concentration difference reaches the threshold value (S26: YES) or the number of actuators 11n4 reaches the maximum number (S27: YES), the control unit 90 ends the allocation of the actuators 11n4 to the nth power supply circuit. (S30), it is determined whether or not all the actuators 11n4 have been assigned to the power supply circuit (S31).

When the allocation of all the actuators 11n4 to the power supply circuit is not completed (S31: NO), the control unit 90 returns the process to S25 with n = n + 1 (S32), and the allocation to the power supply circuit is completed. A predetermined number of actuators 11n4 that do not exist are assigned to the nth power supply circuit in order from the actuator 11n4 having the smallest concentration.

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

In S33, the control unit 90 determines whether or not n ≧ 6.

When n ≧ 6 (S33: NO), the control unit 90 sets the threshold value T = T × 0.9 (S34), erases the allocated data stored in the RAM 93, and then returns the process to S24. That is, when the actuator 11n4 is not assigned to any of the power supply circuits 11e1 to 11e6 (in other words, when any one 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 value T and executes the allocation process again (in other words, the actuator 11n4 is reassigned in order from the first power supply circuit 11e1). By lowering the threshold value T and executing the allocation process again, the actuator 11n4 can be reliably assigned.

In the example of FIG. 11A, the maximum number (540) 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 11e4 is assigned to the fourth power supply circuit 11e4. Less than (50) actuators 11n4 are assigned (S26: YES → S30), less than the maximum number (10) 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 (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 "allocation processing". By the allocation process (S24 to S34), any one of the plurality of actuators 11n4 is assigned to each of the six power supply circuits 11e1 to 11e6.

When n ≧ 6 (S33: YES), the control unit 90 determines whether or not n = 6 (S35).

In the example of FIG. 11B, the maximum number (540) actuators 11n4 are 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 Less than the maximum number (400, 190, 7) actuators 11n4 are assigned to each of ~ 11e5 (S26: YES → S30), and less than the maximum number (3) actuators 11n4 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 determines the specific circuit among the six power supply circuits 11e1 to 11e6 (the “specific circuit” is the power supply circuit in which the number of actuators 11n4 does not reach the maximum number. It is determined whether or not the concentration difference of) is equal to or less than a predetermined value (S36: determination process).

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

For example, in the example of FIG. 11B, there are four specific circuits (third to sixth power supply circuits), and the concentration difference between the plurality of actuators 11n4 assigned to the third power supply circuit is 11D (D: concentration unit). The concentration difference in the plurality of actuators 11n4 assigned to the fourth power supply circuit is 10D, the concentration difference in the plurality of actuators 11n4 assigned to the fifth power supply circuit is 9D, and the concentration difference in the plurality of actuators 11n4 assigned to the sixth power supply circuit is 9D. It is assumed that the difference 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 (11D) of the first power supply circuit is a predetermined value (mean value + fixed value α = 10). It is judged that it is not less than .5D) (S36: NO).

When there are a plurality of specific circuits, the control unit 90 returns the process to S34 when the concentration difference is not equal to or less than a predetermined value in at least one of the plurality of specific circuits (S36: NO). 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). Reassign the actuators 11n4 in order from the beginning).

For example, in the example of FIG. 11B, it is determined that the concentration difference of the first power supply circuit is not equal to or less than a predetermined value as described above (S36: NO), and the allocation process (S24 to S34) is performed with 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. 11C, there are four specific circuits (third to sixth power supply circuits), and the concentration difference between the plurality of actuators 11n4 assigned to the third power supply circuit is 10.1D (D: concentration unit). , The density difference between the plurality of actuators 11n4 assigned to the fourth power supply circuit is 10.1D, the concentration difference between the plurality of actuators 11n4 assigned to the fifth power supply circuit is 9.8D, and the plurality of actuators 11n4 assigned to the sixth power supply circuit. It is assumed that the concentration difference in the actuator 11n4 of the above 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, the concentration differences of all the specific circuits (third to sixth power supply circuits) are predetermined values (mean values). It is determined that the value is + fixed value α = 10.5D) or less (S36: YES).

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

When 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 stored in the RAM 93 at the time of determination in S37 and the actuator 11n4, and performs processing. Return to S34. That is, in this case, the control unit 90 creates and stores data related to another correspondence relationship while holding the data related to the correspondence relationship obtained by the current allocation processing (S24 to S34).

When the threshold value T is less than the lower limit value Tx (S37: YES), the control unit 90 is a power supply circuit including a specific circuit in which the concentration difference is determined to be equal to or less than a predetermined value in the correspondence relationship stored in the RAM 93 (S36). It is determined whether or not there are a plurality of (corresponding relationships between 11e1 to 11e6 and the actuator 11n4) (S38).

When there are a plurality of correspondences (S38: YES), the control unit 90 holds in the RAM 93 the correspondence in which the average value of the concentration differences in the six power supply circuits 11e1 to 11e6 is the smallest among the plurality of correspondences, and other than that. The correspondence between the above is erased from the RAM 93 (S39).

For example, in the example of FIG. 11C, it is determined that the threshold value T is not less than the lower limit value Tx (S37: NO), the allocation process (S24 to S34) is executed again with the threshold value T = T × 0.9, and FIG. It is assumed that the correspondence of 11 (d) is obtained. Then, in the example of FIG. 11 (d), when it is determined that the threshold value T is less than the lower limit value Tx (S37: YES), the correspondences stored in the RAM 93 at this point are shown in FIGS. 11 (c) and 11 (c). It is determined that there are a plurality of correspondences stored in the RAM 93, which are the two of (d) (S38: YES). In this case, of the correspondences shown in FIGS. 11C and 11D, one of the correspondences in which the average value of the concentration differences in the six power supply circuits 11e1 to 11e6 is small is held in the RAM 93, and the other correspondence is held. The relationship is erased 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 the seventh power supply circuit not provided in the head 11. In the example of FIG. 11 (e), it is determined that the concentration difference of the specific circuit is not less than or equal to the predetermined value (S36: NO), and the allocation process (S24 to S34) is executed again. 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 = 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 latest S36 (judgment processing). The correspondence relationship in FIG. 11 (e) (that is, the correspondence relationship when n> 6) is erased from the RAM 93 (S40).

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

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

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

Further, according to the present embodiment, the processing can be simplified by performing S36 (judgment processing) not for all the power supply circuits 11e1 to 11e6 but for the 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 is not equal to or less than a predetermined value (S36: NO) in at least one of the plurality of specific circuits. .. In this case, the above effect (the effect of suppressing the density difference in the plurality of actuators 11n4 assigned to each power supply circuit 11e1 to 11e6 and appropriately performing unevenness correction) can be obtained more reliably.

When the control unit 90 has a plurality of correspondences between the power supply circuits 11e1 to 11e6 including the specific circuit determined that the concentration difference is equal to or less than a predetermined value (S36: YES) and the actuator 11n4 (S38: YES), the control unit 90 has a plurality of correspondences. Among the correspondence relationships, S12 (discharge processing) is executed based on the correspondence relationship in which the average value of the concentration differences in the six power supply circuits 11e1 to 11e6 is the smallest (S39). In this case, the above effect (the effect of suppressing the density difference in 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 (sort processing) before the allocation processing (S24 to S34), and sets the actuator 11n4 to one of the six power supply circuits 11e1 to 11e6 in the order sorted by S22 (sort processing). (S25), and it is determined whether or not the concentration difference has reached the threshold value in the power supply circuit (S26: first determination step). Then, when it is determined that the concentration difference has not reached the threshold value (S26: NO), the control unit 90 determines whether or not the number of actuators 11n4 assigned to the power supply circuit has reached the maximum number (S27). : Second determination step), when it is determined that the number of actuators 11n4 has not reached the maximum number (S27: NO), S26 (first determination step) is executed again for the power supply circuit. The control unit 90 determines that the concentration difference has reached the threshold value (S26: YES), or that the number of actuators 11n4 has reached the maximum number (S27: YES). (S30), the actuators 11e1 to 11e6 of the six power supply circuits 11e1 to 11e6 that are different from the power supply circuit (S32), and the actuators 11n4 that have not been assigned are not completed. S26 (first determination step) is executed. In this case, the allocation processing (S24 to S34) can be efficiently executed.

It is determined that the concentration difference of the specific circuit is not less than or equal to the predetermined value (S36: NO), the allocation processing (S24 to S34) is executed again, and by executing S26 (first determination step) and S27 (second determination step), One of the plurality of actuators 11n4 may not be assigned to any of the six power supply circuits 11e1 to 11e6 (S35: NO, see FIG. 11E). In this case, the control unit 90 executes S12 (discharge processing) based on the correspondence between the power supply circuits 11e1 to 11e6 and the actuator 11n4, which are the targets of the latest S36 (determination processing) (S40). In this case, it is possible to obtain (the effect of suppressing the density difference in the plurality of actuators 11n4 assigned to each power supply circuit 11e1 to 11e6 and appropriately performing unevenness correction) while reliably allocating the actuators 11n4. ..

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

When the control unit 90 determines that the density difference of the specific circuit is not equal to or less than a predetermined value (S36: NO), the control unit 90 lowers the threshold value 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 value T is a value obtained by subtracting the minimum concentration Dmin in the plurality of actuators 11n4 from the maximum concentration Dmax in the plurality of actuators 11n4, and x (the maximum number of the plurality of actuators 11n4 in the six power supply circuits 11e1 to 11e6 in sequence. It is a value divided by the number of power supply circuits in which the number of actuators 11n4 does not reach the maximum number when allotted until the number reaches. In this case, the allocation processing (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 the concentration differences in the plurality of specific circuits. In this case, S36 (judgment processing) can be efficiently executed, and the above effect (the effect of suppressing the density difference in the plurality of actuators 11n4 assigned to each power supply circuit 11e1 to 11e6 and appropriately performing unevenness correction). Can be obtained more reliably.

<Modification example>
Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various design changes can be made as long as it is described in the claims.

For example, in the above-described embodiment, the actuators with the lowest concentration are assigned in order, but the actuators with the highest concentration may be assigned in order. In the actuators sorted in order of concentration, by assigning in order from the one with the smallest concentration change (the one with the smallest concentration in the example of FIG. 11), the concentration difference reaches the maximum number without reaching the threshold value in the first half stage. Since the allocation can be performed up to, the allocation process can be executed efficiently.

When there are a plurality of specific circuits, in the above-described embodiment, when it is determined that the concentration difference is not less than or equal to a predetermined value (S36: NO) in at least one of the plurality of specific circuits, the allocation process is executed again. When it is determined that the concentration difference is not less than or equal to the predetermined value (S36: NO) in all the specific circuits, the allocation process may be executed again.

The predetermined value is limited to a value based on the average value of the concentration differences in a plurality of specific circuits (for example, the sum of the above average value derived from the read data generated in S2 and the fixed value α stored in the ROM 92). However, 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-described embodiment.

When lowering the threshold, the threshold is multiplied by 0.9 in the above-described embodiment, but the present invention is not limited to this. For example, the threshold may be multiplied by any minority other than 0.9, divided by any number greater than 1, or subtracted by any positive number. Further, the threshold value may be lowered differently between the first S34 and the second S34.

The actuator is not limited to the piezoelectric method, and may be another method (for example, a thermal method using a heat generating element, an electrostatic method using electrostatic force, etc.).

The head is of the line type in the above-described embodiment, but may be of the serial type.

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

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

The liquid discharge device according to the present invention is not limited to the multifunction device (that is, it may be a device having an image forming unit but not an image reading unit). The present invention can also be applied to printers, facsimiles, copiers and the like. The present invention is also applicable to a liquid discharge device used for purposes other than image recording (for example, a liquid discharge device that discharges a conductive liquid onto a substrate to form a conductive pattern).

The inspection image is read (S2) by a device different from the liquid discharge device according to the present invention, and then the association step (S2) is performed by the liquid discharge device according to the present invention based on the read data received from the other device. S3) may be executed. For example, the inspection image may be read (S2) using a spectrophotometer (“SpectroEye” manufactured by X-Rite, etc.). In this case, the liquid discharge device according to the present invention may execute the association 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, and can also be distributed via a communication line.

According to the reference example of the present invention, "a plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and an actuator assigned to the plurality of actuators are output different voltages from each other. A plurality of power supply circuits and a control unit are provided, and the control unit has a concentration difference of liquid discharged from the nozzle of the actuator assigned to each of the plurality of power supply circuits to be a predetermined value or less. As described above, each of the plurality of actuators is assigned to one of the plurality of power supply circuits, and any of the plurality of actuators is assigned to each of the plurality of power supply circuits. Liquid discharge device "," 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 the actuators assigned to the plurality of actuators. A control method for controlling a liquid discharge device including the power supply circuit of the above, wherein the concentration difference of the liquid discharged 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 allocation process is characterized in that 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. Control method "and" Output different voltages to a plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and an actuator assigned to the plurality of actuators. In the actuator assigned to each of the plurality of power supply circuits, the liquid discharge device including the plurality of power supply circuits is provided so that the concentration difference of the liquid discharged from the nozzles is equal to or less than a predetermined value. A program characterized in that each of a 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, so as to function as an allocation means. " Is provided. In this reference example, S36 (judgment processing) is not limited to being performed on a specific circuit in which the number of actuators 11n4 has not reached the maximum number, and may be performed on all power supply circuits 11e1 to 11e6.

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

Claims (11)

With multiple nozzles
Multiple actuators provided for each of the multiple nozzles,
A plurality of power supply circuits that output different voltages to the assigned actuators among the plurality of actuators, and
With a control unit
The control unit
The allocation process, which allocates one of the plurality of actuators to each of the plurality of power supply circuits,
The discharge process, in which the plurality of actuators are driven by each of the plurality of power supply circuits assigned in the allocation process and the liquid is discharged from the plurality of nozzles, is executed.
After the allocation process and before the discharge process,
Among the plurality of power supply circuits, in a specific circuit which is a power supply circuit in which the number of actuators does not reach the maximum number defined for the power supply circuit, the maximum value of the concentration of the liquid discharged from the nozzle and the said. A judgment process is executed to determine whether or not the concentration difference, which is the difference from the minimum concentration of the liquid discharged from the nozzle, is equal to or less than a predetermined value.
A liquid discharge device, 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
When there are a plurality of the specific circuits, the allocation process is re-executed when it is determined in the determination process that the concentration difference is not equal to or less than the predetermined value in at least one of the plurality of specific circuits. The liquid discharge device according to claim 1. The control unit
When there are a plurality of correspondences between the plurality of power supply circuits 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 and the plurality of actuators.
The liquid discharge according to claim 1 or 2, wherein the discharge process is executed 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 plurality of correspondence relationships. apparatus. The control unit
Prior to the allocation process, a sort process is executed in which the plurality of actuators are sorted in order of the concentration of the liquid discharged from the nozzle by driving the actuator.
In the allocation process
A first determination in which the plurality of actuators are assigned to one of the plurality of power supply circuits in the order sorted by the sort process, and it is determined whether or not the concentration difference has reached a threshold value in the power supply circuit. Steps and
When it is determined in the first determination step that the concentration difference has not reached the threshold value, it is determined whether or not the number of the actuators assigned to the power supply circuit has reached the maximum number. Step and perform,
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.
When it is determined in the first determination step that the concentration 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 power supply circuit is contacted. The first determination step is executed for the power supply circuit other than the power supply circuit among the plurality of power supply circuits and the actuator for which the allocation is not completed among the plurality of actuators. The liquid discharge device according to any one of claims 1 to 3, wherein the liquid discharge device is characterized in that. The control unit
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 and the allocation process is executed again, the plurality of actuators are executed by executing the first determination step and the second determination step. When any of the above cannot be assigned to any of the plurality of power supply circuits,
The liquid discharge device according to claim 4, wherein the discharge process is executed based on the correspondence between the plurality of power supply circuits, which are the targets of the latest determination process, and the plurality of actuators. The control unit
In the allocation process, when any of the plurality of actuators is not assigned to each of the plurality of power supply circuits due to the execution of the first determination step and the second determination step,
The liquid discharge device according to claim 4 or 5, wherein the threshold value is lowered and the allocation process is executed again. The control unit
Any of claims 4 to 6, wherein 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 threshold value is lowered and the allocation process is executed again. The liquid discharge 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 until the plurality of actuators are sequentially assigned to each of the plurality of power supply circuits until the maximum number is reached. The liquid discharge device according to claim 6 or 7, wherein the number of actuators is a value divided by the number of power supply circuits that do not reach 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 differences 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 for outputting different voltages to the actuators assigned to the plurality of actuators are provided. It is a control method that controls the liquid discharge device.
The allocation process, which allocates one of the plurality of actuators to each of the plurality of power supply circuits,
The discharge process, in which the plurality of actuators are driven by each of the plurality of power supply circuits assigned in the allocation process and the liquid is discharged from the plurality of nozzles, is executed.
After the allocation process and before the discharge process,
Among the plurality of power supply circuits, in a specific circuit which is a power supply circuit in which the number of actuators does not reach the maximum number defined for the power supply circuit, the maximum value of the concentration of the liquid discharged from the nozzle and the said. A judgment process is executed to determine whether or not the concentration difference, which is the difference from the minimum concentration of the liquid discharged from the nozzle, is equal to or less than a predetermined value.
A control method, 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. A plurality of nozzles, a plurality of actuators provided for each of the plurality of nozzles, and a plurality of power supply circuits for outputting different voltages to the actuators assigned to the plurality of actuators are provided. Liquid discharge device,
An assigning means, which assigns one of the plurality of actuators to each of the plurality of power supply circuits.
The discharge means and the discharge means, which drive the plurality of actuators by each of the plurality of power supply circuits assigned by the allocation means and discharge the liquid from the plurality of nozzles.
After allocation by the allocation means and before discharge by the discharge means,
Among the plurality of power supply circuits, in a specific circuit which is a power supply circuit in which the number of actuators does not reach the maximum number defined for the power supply circuit, the maximum value of the concentration of the liquid discharged from the nozzle and the said. A program that functions as a determination means for determining whether or not the concentration difference, which is the difference from the minimum concentration of the liquid discharged from the nozzle, is equal to or less than a predetermined value.
A program, characterized in that, when the determination means determines that the concentration difference of the specific circuit is not equal to or less than the predetermined value, the allocation means executes allocation again.

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