JP2021084392A - Liquid discharge device, and discharge control method of the liquid discharge device - Google Patents

Abstract

To stabilize discharge of the liquid discharge device for discharging a liquid to a linear discharged medium from a discharge head almost without degrading productivity.SOLUTION: A liquid discharge device 100 includes a conveying part which conveys a discharged medium 101, a discharge head 1 which has a plurality of nozzle arrays 10a, 10b with a plurality of nozzles arranged in a line and parallel to a conveying direction of the discharged medium 101, and a control part 401 which controls discharge of each of the nozzle arrays 10a, 10b of the discharge head 1. Discharge operation for maintenance and discharge operation for coloring can be executed simultaneously by allocating the discharge operation for maintenance and the discharge operation for coloring to each of the nozzle arrays of the plurality of nozzle arrays 10a, 10b.SELECTED DRAWING: Figure 10

Description

The present invention relates to a liquid discharge device that discharges a liquid to a linear or band-shaped discharge medium such as a thread, and a discharge control method in the liquid discharge device.

In an inkjet image forming apparatus, it is known that when the ejection head is not capped for a long time, the ink in the vicinity of the nozzle thickens due to drying or the like, which causes ejection abnormality. Therefore, in order to prevent abnormal ejection due to thickening of the ink in the nozzle, empty ejection (flushing) is periodically performed as ejection for maintenance outside the image formation (printing) area, and the thickened ink is discarded. Therefore, there is a technique for stabilizing ejection for printing (for example, Patent Documents 1 and 2).

In such an empty discharge method, empty discharge is performed for each scan by dividing one job. For example, in Patent Document 1, in a line printer in which nozzle rows are arranged so as to be orthogonal to a paper transport direction, blank ejection is performed at page breaks between prints to remove thickened ink.

Further, in Patent Document 2, in the serial type inkjet method, empty ejection receivers are provided on both sides of the scanning region, and empty ejection is performed on those portions during scanning.

On the other hand, as shown in Patent Document 3, when a medium such as a thread is colored by using an inkjet ejection head, the machine configuration is similar to that of a line printer, but the medium is arranged parallel to the nozzle row. , There is no page break or one job is long. As a result, in this device, the nozzle row used for ejection is always arranged in the scanning region (colored region) on the yarn, so that empty ejection at page breaks is performed like a normal line printer. In addition, since the head does not move like a serial printer, empty ejection cannot be performed during the coloring operation.

Here, when an empty discharge operation is to be performed in a thread coloring device as in Patent Document 3, the thread transfer is stopped, the nozzle row is retracted from the thread, and the thread is empty due to the maintenance operation during the coloring operation. After ejecting and returning the nozzle train to the scanning position, it is necessary to restart the coloring operation, that is, it is necessary to stop the machine in order to carry out empty ejection. Therefore, for uniform and stable discharge, if the frequency of the empty discharge operation is increased, other operations are stopped each time, and the productivity is lowered.

Therefore, in view of the above circumstances, it is an object of the present invention to provide a liquid discharge device that can stabilize the discharge without lowering the productivity and discharges the liquid to the linear discharge medium by the discharge head. ..

In order to solve the above problems, in one aspect of the present invention,
A transport unit that transports the medium to be discharged and
A discharge head provided with a plurality of nozzle rows in which a plurality of nozzles are arranged in a row in parallel with the transport direction of the discharge medium.
It has a control unit that controls the ejection of each nozzle row of the ejection head, and has.
A liquid discharge device capable of assigning a discharge operation for maintenance and a discharge operation for coloring to each nozzle row of the plurality of nozzle rows and simultaneously executing a discharge operation for maintenance and a discharge operation for coloring. ,I will provide a.

According to one aspect, in a liquid discharge device that discharges a liquid to a linear discharge medium by a discharge head, the discharge can be stabilized with almost no reduction in productivity.

The schematic explanatory view of an example of the coloring / embroidery system including the liquid discharge device which concerns on one Embodiment of this invention. The side schematic of the liquid application part in the liquid discharge device of one Embodiment of this invention. The lower surface schematic view of the liquid application part of one Embodiment of this invention. The figure which explains the movement of the head in the direction orthogonal to the thread transfer direction in the liquid application part of one Embodiment of this invention, was seen from the direction orthogonal to the transfer direction. The schematic explanatory view of the moving means of the head of the liquid application part and the moving means of the cap of the maintenance recovery means. FIG. 3 is a control block diagram of a portion related to liquid discharge, head movement, and cap raising / lowering in the liquid discharge device according to the first embodiment of the present invention. FIG. 6 is a functional block diagram of the head control unit of FIG. The graph which shows the example of the drive waveform applied by the drive waveform application means. The timing chart of the control in the first embodiment. FIG. 5 is a flow chart for controlling the replacement of nozzle rows and the waveform to be applied in the first embodiment. FIG. 3 is a control block diagram of a portion related to liquid discharge, head movement, cap raising / lowering, and nozzle state detection in the liquid discharge device according to the second embodiment of the present invention. FIG. 3 is a control block diagram of a portion related to liquid discharge, head movement, cap raising / lowering, and nozzle state detection in the liquid discharge device according to the third embodiment of the present invention. Operational conceptual diagram showing residual vibration generated in a pressure chamber. FIG. 6 is a schematic explanatory view of an example of a coloring / embroidery system including a liquid discharge device equipped with a sensor for detecting a landing state on a thread according to a fourth embodiment of the present invention. The schematic explanatory view of an example of the coloring system equipped with the liquid discharge device which concerns on one Embodiment of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each of the drawings below, the same components may be designated by the same reference numerals and duplicate description may be omitted.

<Overall configuration>
First, a coloring / embroidery device including a liquid discharge device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic explanatory view of an example of a coloring / embroidery apparatus according to the present invention. FIG. 2 is a schematic side view of the vicinity of the liquid applying portion in the liquid discharging device according to the embodiment of the present invention. FIG. 3 is a bottom view of the liquid applying portion according to the embodiment of the present invention.

The coloring / embroidery device 1000 is an in-line type embroidery device, and includes a supply reel 102 on which a thread 101 is wound, a liquid application unit 103, a fixing unit 104, a post-processing unit 105, and an embroidery head 106. There is. The supply reel 102, the liquid applying unit 103, the fixing unit 104, and the post-processing unit 105, excluding the embroidery head 106, function as the liquid discharge device (coloring unit, dyeing unit) 100 in the present embodiment.

The thread 101 drawn from the supply reel 102 is guided by the transport rollers 108 and 109 and continuously crawls to the embroidery head 106.

The roller 109 is provided with a rotary encoder (hereinafter, may be simply referred to as an encoder) 405. The encoder 405 includes an encoder wheel 405a that rotates together with the roller 109 and an encoder sensor 405b that reads a slit in the encoder wheel 405a.

The liquid application unit 103 includes a plurality of heads 1 (1K to 1Y) that discharge and apply a liquid of a required color to a thread 101 that is drawn out from a supply reel 102 and is conveyed, and a plurality of heads 1 that perform maintenance on each head 1. It includes a maintenance unit 2 composed of individual maintenance units 20 (20K to 20Y) and the like.

Hereinafter, the thread conveying direction from the liquid applying portion 103 to the embroidery head 106 is referred to as X, the depth direction (head moving direction) of the coloring / embroidery apparatus 1000 is referred to as Y, and the height direction (vertical direction) is referred to as Z.

With reference to FIG. 2, in the liquid applying unit 103, the plurality of heads 1K to 1Y are ejection heads that eject different colors, for example, 1Y ejects black (K) droplets (ink droplets). The head, 1C is a head that ejects a droplet of cyan (C), 1M is a head that ejects a droplet of magenta (M), and 1Y is a head that ejects a droplet of yellow (Y). The order of the colors is an example, and the colors may be arranged in an order different from this description.

Further, on the lower side of the liquid applying portion 103, individual maintenance units 20K, 20C, 20M, 20Y are arranged so as to face the heads 1K, 1C, 1M, 1Y, respectively.

Here, as shown in FIG. 3, the head 1K has a nozzle surface 12 on which nozzle rows 10a and 10b in which a plurality of nozzles 11 for ejecting droplets are arranged are formed. The heads 1K to 1Y are arranged so that the direction of the nozzle row (arrangement of the nozzles 11) is parallel to the transport direction (thread feed direction) of the thread 101.

In the head 1K, the ink droplets ejected by the nozzle 11 in one row (nozzle row 10a in FIG. 3) located directly below the thread 101 land on the thread to color the thread. Although FIG. 3 shows an example in which two rows of two nozzle rows 10a and 10b are arranged on the nozzle surface 12 of the head 1, the number of nozzle rows provided on the head 1K may be one row. , Or it may be 3 or more rows. As shown in FIG. 3, the other heads 1C, 1M, and 1Y also have the same configuration.

Returning to FIG. 1, the fixing unit 104 performs a fixing process (drying process) on the thread 101 to which the liquid discharged from the liquid applying unit 103 is applied. The fixing portion 104 is provided with heating means such as an infrared irradiation means and a warm air blowing means, and heats and dries the yarn 101.

The post-processing unit 105, for example, applies a cleaning means for cleaning the yarn 101, a tension adjusting means for adjusting the tension of the yarn 101, a feed amount detecting means for detecting the movement amount of the yarn 101, and a lubricant on the surface of the yarn 101. Includes lubricant applying means and the like.

The embroidery head 106 embroiders a pattern such as a pattern or a pattern on the cloth by sewing it into the cloth using the colored thread 101.

In the present embodiment, the liquid discharge device is described as an example of the coloring / embroidery device 1000, but the present invention is not limited to this, and the present invention is a device using a linear object such as a thread, for example, a loom. , It can also be applied to devices such as sewing machines.

The "yarn" is a linear object (line) to which a glass fiber yarn, a wool yarn, a cotton yarn, a synthetic yarn, a metal yarn, a wool, a cotton, a polymer, or a mixed yarn of a metal, a yarn, a filament, or a liquid can be applied. Shaped member, continuous base material), including braided cord, flat cord, etc.

In addition to the linear object, as a discharge medium that can be dyed with ink droplets, in addition to the above linear object, a strip-shaped member (continuous base material) to which a liquid can be applied such as a rope, a cable, and a cord is also used. included. Each ejected medium is a linear or strip-shaped medium having a narrow width and continuous in the transport direction.

<Movement of head position>
Next, the movement of the head and the raising and lowering of the cap will be described with reference to FIGS. 4 and 5. FIG. 4 is a diagram illustrating the movement of the head in the direction orthogonal to the thread transport direction in the liquid applying portion of the liquid discharge device according to the embodiment of the present invention. FIG. 4 is a schematic explanatory view of the head moving means of the liquid applying portion 103 and the moving mechanism of the cap 21 of the maintenance unit 20.

Specifically, in FIG. 4, (a) shows the position of the head 1K in a state where the droplet can be ejected from the nozzle row 10a onto the thread 10, and (b) shows the position where the droplet is from the nozzle row 10b to the thread 101. The position of the head 1K in a state where the nozzle can be ejected is shown above, and (c) shows the position of the head 1K in a state where the nozzle rows 10a and 10b are capped by the cap 21K.

As shown in FIG. 4, by moving the head 1K perpendicularly to the transport direction of the thread 101, it is possible to color the nozzle row 10a, color the nozzle row 10b, and cap the nozzle surface 12 with the cap 21K. The moving direction Y of the head is the same direction as the device depth direction shown in FIG.

Similarly for other heads, the heads 1K to 1Y of each color can be freely moved in the head moving direction in order to select and maintain the nozzle row to be used.

Further, as shown in FIG. 4, there are two rows of nozzle rows 10a and 10b on the lower surface of the head 1, and the nozzle rows in which ink droplets land on the yarn to color the yarn move the head 1 to make the threads true. By setting the nozzle row to be discharged above, the nozzle row to be used can be selected as appropriate.

In addition to the recovery operation by capping that engages with the cap 21K, the maintenance unit 20K collects ink that protrudes from the thread 101 and does not land on the thread 101 on the collection surface 22 which is the upper surface where the cap 21K and the thread 101 are not provided. Also do.

A home position sensor (HP sensor) 305 is provided in the maintenance unit 20 as a reference for moving the head 1. Note that FIG. 5 shows an example in which the HP sensor 305 that defines the home position position of the head 1 is provided at the end of the maintenance unit 20, but the HP sensor 305 is located at another position in the head moving direction. It may be provided.

Here, a mechanism for moving each of the heads 1K to 1Y in the moving direction (device depth direction) will be described with reference to FIG. FIG. 5 is a schematic explanatory view of the head moving means of the liquid applying unit 103 and the moving means of the cap 21 of the maintenance unit 2.

As shown in FIG. 5, the head 1 is supported by a movable carriage 141. The carriage 141 can be moved in the movable direction by moving the arms 142 and 143 that support the carriage 141 by the head moving motor 304. As an example of head movement, for example, the arm 142 itself extending in the horizontal direction may be expanded or contracted, or the carriage 1411 may be moved by changing the position of the carriage 141 with respect to the arm 142. In the present embodiment, the carriage 141, the arms 142, 143, and the head moving motor 304 are combined to form a head moving portion (head moving means) 140.

With such a structure, the head 1K supported by the carriage 131 can be moved to the position of the cap 21 during standby, and can be moved to the position of the thread 101 during coloring.

It is preferable that the head moving portion 140, which is a movable portion for moving the position of the discharge head 1, is provided for each head. As a result, the replacement timing can be changed for each head.

Further, the cap 21 can be raised and lowered by the raising and lowering arm 23 driven by the cap raising and lowering motor 24 in the maintenance unit 20. During standby, the cap 21 is raised to cap the head 1 as shown in FIG. 4 (c) in order to prevent the ink of the head 1K from drying. At the time of coloring, as shown in FIGS. 4 (a) and 4 (b), the cap 21 is lowered for decapping.

Note that FIG. 4 shows an example in which the cap 21 is arranged on the back side (+ Y side) of the coloring / embroidery device 1000 in the maintenance unit 20, but as shown in FIG. 6, the cap 21 is arranged in the maintenance unit 20. May be arranged on the front side (−Y side) of the coloring / embroidery apparatus 1000.

<Control block>
FIG. 6 is a control block diagram of a portion related to liquid discharge, head movement, and cap raising / lowering in the liquid discharge device according to the first embodiment of the present invention.

The head 1 has a plurality of piezoelectric elements 13 as pressure generating elements that generate pressure for discharging liquid from the plurality of nozzles 11. The drive waveform applying means for applying the drive waveform to the head 1 includes a head control unit 401, a drive waveform generation unit 402, a waveform data storage unit 403, and a head driver 410, and discharge timing generation for generating discharge timing. The unit 404 is provided.

Further, as the transfer control means, a transfer control unit 300, a rotary encoder 405 of the transfer roller 109, a rotary encoder 301 on the embroidery head side, a transfer motor 302 and the like are provided.

Further, as the head position control means, a head position control unit 303, a head moving motor 304, and an HP sensor 305 are provided.

The head control unit 401 is an example of the control unit, and when it receives the discharge timing pulse stb, it outputs a discharge synchronization signal LINE that triggers the generation of the drive waveform to the drive waveform generation unit 402. Further, the head control unit 401 outputs the discharge timing signal CHANGE corresponding to the delay amount from the discharge synchronization signal LINE to the drive waveform generation unit 402.

The drive waveform generation unit 402 generates a common drive waveform Vcom at a timing based on the discharge synchronization signal LINE and the discharge timing signal CHANGE.

The head control unit 401 receives the thread coloring data, and based on the thread coloring data, a mask for selecting a predetermined waveform of the common drive waveform Vcom according to the size of the liquid discharged from each nozzle 11 of the head 1. The control signal MN is generated. The mask control signal MN is a timing signal synchronized with the discharge timing signal CHANGE.

Then, the head control unit 401 transfers the thread coloring data SD, the synchronous clock signal SCK, the latch signal LT instructing the latch of the thread coloring data, and the generated mask control signal MN to the head driver 410.

The head driver 410 includes a shift register 411, a latch circuit 412, a gradation decoder 413, a level shifter 414, and an analog switch array 415.

The shift register 411 inputs the thread coloring data SD and the synchronous clock signal SCK transferred from the head control unit 401. The latch circuit 412 latches each resist value of the shift register 411 by the latch signal LT transferred from the head control unit 401.

The gradation decoder 413 decodes the value (thread coloring data SD) latched by the latch circuit 412 and the mask control signal MN, and outputs the result. The level shifter 414 converts the logic level voltage signal of the gradation decoder 413 into a level at which the analog switch AS of the analog switch array 415 can operate.

The analog switch AS of the analog switch array 415 is a switch that is turned on / off by the output of the gradation decoder 413 given via the level shifter 414. This analog switch AS is provided for each nozzle 11 included in the head 1, and is connected to the individual electrodes of the piezoelectric element 13 corresponding to each nozzle 11. Further, a common drive waveform Vcom from the drive waveform generation unit 402 is input to the analog switch AS. Further, as described above, the timing of the mask control signal MN is synchronized with the timing of the common drive waveform Vcom.

Therefore, by switching the analog switch AS on / off at an appropriate timing according to the output of the gradation decoder 413 given via the level shifter 414, each nozzle 11 from the drive waveforms constituting the common drive waveform Vcom The waveform applied to the piezoelectric element 13 corresponding to is selected. As a result, the size of the droplets ejected from the nozzle is controlled.

The discharge timing generation unit 404 generates and outputs a discharge timing pulse stb every time the thread 101 is moved by a predetermined amount from the detection result of the rotary encoder 405 that detects the rotation amount of the roller 109 in FIG.

Here, the thread 101 is conveyed (thread feed) by being consumed by the embroidery operation by the embroidery head 106 on the downstream side. The rotary encoder 301 on the downstream side of the embroidery head 106 is a feed amount detecting means for detecting the movement amount of the thread 101 on the embroidery head 106.

When the thread 101 is conveyed, the roller 109 guiding the thread 101 rotates, the encoder wheel 405a of the rotary encoder 405 rotates, and an encoder pulse proportional to the linear speed of the thread 101 is generated and output from the encoder sensor 405b. Will be done.

The discharge timing pulse stb is generated by the discharge timing generation unit 404 by the encoder pulse from the rotary encoder 405, and is used as the discharge timing of the head 1. The liquid is applied to the thread 101 from the beginning of the movement of the thread 101, and even if the linear velocity of the thread 101 changes, the interval of the discharge timing pulse stb changes according to the encoder pulse, so that the landing position of the droplet is displaced. Can be prevented.

The transfer control unit 300 is an example of the transfer control means, determines the transfer speed of the yarn 101 based on the movement amount of the rotary encoder 301 on the downstream side, and causes the transfer motor 302 to transfer the yarn 101 at the determined transfer speed. The yarn is conveyed by rotating the roller 108. Further, the rotary encoder 405 detects the speed and controls the thread transfer of the transfer motor 302.

The head position control unit 303 is an example of the head position control means, and rotates the head movement motor 304 based on the head position command from the head control unit 401 to move the heads 1K to 1Y to a predetermined position.

For example, when the head moving motor 304 is a stepping motor, the position is controlled from the state where the home position (HP) is detected by the HP sensor 305, the coloring position in the nozzle row 10a, the coloring position in the nozzle row 10b, the capping position, and the like. The head movement motor 304 is controlled to be rotated by the number of STEPs according to the distance from the position to the corresponding position from the HP. The head position control unit 303 notifies the head control unit 401 that the head movement is completed after the STEP number of rotations according to the distance.

The cap elevating control unit 306 rotates the cap elevating motors 24K to 24Y based on the capping and decapping instructions from the head control unit 401 to elevate and lower the caps 21K to 21Y.

For example, when the cap elevating motor 24 is a stepping motor, the cap elevating control unit 306 rotates the cap elevating motor 24 by the number of STEPs according to the distance between the capping position at the upper end and the decapping position at the lower end. Control to make it. The cap elevating control unit 306 rotates the cap elevating motor 24 by the number of STEPs according to the distance from the upper end to the lower end, and then caps and decapps the nozzle row by elevating and lowering the cap 21 with respect to the head control unit 401. , Notify that it is completed.

FIG. 7 is a functional block diagram of the situation determination unit 500 included in the head control unit 401 according to the first embodiment of FIG.

Generally, in the nozzle row during the coloring operation, there are nozzles that do not discharge or are not used depending on the coloring conditions (thread coloring data), so the ink (liquid) thickens in the nozzles due to long-term decap. Therefore, the discharge may become unstable. Therefore, in the present invention, in a plurality of nozzle rows, they are located on the yarn and are not located on the yarn before the ejection from the nozzles of the nozzle row used for the coloring operation becomes unstable. The nozzle row is maintained, and then the maintained nozzle row is moved onto the thread and used for the discharge operation to prevent abnormal discharge.

In the present embodiment, the head control unit 401 has a function of detecting (determining) in advance that the nozzle discharge becomes unstable, and a function of issuing an empty discharge instruction based on the result. .. In the present embodiment, the head control unit 401 is located on the yarn by using the elapsed time after decapping, the elapsed time after replacement, the coloring condition (non-ejection period in ejection), and the like as determination conditions. Determine if the discharge of the nozzle train inside becomes unstable.

Therefore, in the head control unit 401, as the status determination unit 500, the decapping elapsed time counting unit 501, the decapping elapsed time comparison unit 502, the replacement elapsed time counting unit 503, the replacement elapsed time comparison unit 504, and each nozzle non-ejection It has the functions of the period counting unit 505, the nozzle non-ejection period comparison unit 506, the threshold storage unit 507, the nozzle row destabilization determination unit 508, and the empty discharge operation instruction unit 509 so as to be executable.

The decapping elapsed time counting unit 501 counts the elapsed time after decapping when the nozzle rows 10a and 10b are decapped when the coloring operation is started due to the occurrence of the coloring request. Therefore, the decapping elapsed time counting unit 501 starts counting when the cap 21 lowers and receives the decapped decapping completion information from the cap elevating control unit 306 at the start of coloring.

Then, the decapping elapsed time comparison unit 502 compares the counted decapping elapsed time with the threshold value stored in the threshold storage unit 507, and when the elapsed time exceeds the threshold value, Hi To.

The post-replacement elapsed time counting unit 503 counts the elapsed time after the replacement after the nozzle row to be used is replaced one or more times. Therefore, in the replacement elapsed time counting unit 503, after moving the head 1 in the direction orthogonal to the thread transport direction in order to replace the nozzle rows 10a and 10b, the nozzle row that was not on the thread immediately before is the thread. When it reaches the top and receives the head movement completion information from the head position control unit 303, counting is started.

Then, the replacement elapsed time comparison unit 504 compares the counted elapsed time after replacement with the threshold value stored in the threshold storage unit 507, and when the elapsed time exceeds the threshold value, the replacement time comparison signal. To Hi.

The nozzle-by-nozzle non-ejection period counting unit 505 counts the non-ejection time of the non-ejection nozzles, if any, in the nozzles in the nozzle row during the ejection operation located on the thread. Therefore, data (thread coloring data SD) that is the source of the ejection operation is input to the nozzle-by-nozzle non-ejection period counting unit 505, and the non-ejection period in the nozzle assigned in the coloring data is counted.

Here, in the nozzle row during the ejection operation for coloring, the ejection operation may not be performed depending on the coloring conditions. Specifically, when the droplets are ejected from all the nozzles in the nozzle row to be colored, such as coloring the yarn solidly, the count does not start because there is no non-ejection period. On the other hand, based on the thread coloring data SD, for example, when forming a striped pattern on the thread, there are nozzles used in the nozzle row 10a and nozzles not used.

Alternatively, in a state where the nozzle rows 10aK, 1aC, 1aM, 10aY of each of the heads 1K, 1C, 1M, 1Y of a plurality of colors are present on the thread, the color that colors the thread is a single primary color. There is a head of a color that is not used when it is composed of. In this case, with a head of a color that is not used, all the nozzles in the nozzle row above the thread are non-ejection. In this way, during the coloring operation, the non-ejection period counting unit 505 for each nozzle counts the non-ejection period of unused nozzles in each nozzle of the nozzle row located on the yarn.

Then, the nozzle non-ejection period comparison unit 506 compares the counted non-ejection period with the threshold value stored in the threshold storage unit 507, and when the non-ejection period exceeds the threshold value, a non-ejection period comparison signal is output. Set to Hi.

The nozzle row destabilization determination unit 508 becomes Hi only for an arbitrary period when the decap time comparison signal, the replacement time comparison signal, and the non-discharge period comparison signal become Hi. Specifically, in the case immediately after the start of coloring, when either the decap time comparison signal or the non-discharge period comparison signal becomes Hi, the discharge instability signal which is the output of the nozzle row instability determination unit 508 becomes Hi. Further, after the nozzle row is replaced one or more times after the start of coloring, when the replacement time comparison signal and the non-discharge period comparison signal become Hi, the discharge instability signal becomes Hi for an arbitrary period.

Then, when the discharge instability signal becomes Hi, the empty discharge operation instruction unit 509 instructs the empty discharge operation execution. When the empty discharge operation is instructed, the drive waveform for empty discharge is applied to the piezoelectric element 13 in all the nozzles of the nozzle row 10b that are not on the thread, and the liquid is applied to the region (empty discharge region) that is not on the thread. Performs an empty discharge operation. The period for executing empty discharge or the number of empty discharges is set in advance.

The head control unit 401 also has a function of generating a mask control signal MN, and generates a mask control signal MN based on the thread coloring data SD and an empty discharge instruction from the status determination unit 500.

After that, the head 1 is moved so that the nozzle row in which the empty ejection operation is completed is placed on the thread.

<Drive waveform>
FIG. 8 is a graph showing an example of a drive waveform generated by the drive waveform generation unit 402 in the embodiment of the present invention.

As shown in FIG. 8, the drive waveform (common drive waveform) Vcom of this example has not only a general coloring pulse P1 and a fine drive pulse P2 but also an empty discharge pulse P3 as a waveform configuration. ing.

By the mask control signal MN output from the head control unit 401 based on the thread coloring data SD and the empty discharge instruction, three types of pulses included in the common drive waveform Vcom for each nozzle row or each nozzle in the nozzle row By selecting one of the pulses, even if the drive circuits (head driver 410) of the two nozzle trains with respect to the head 1 are common, different purpose discharge operations can be performed.

By using such a waveform, the present invention can simultaneously perform different purpose discharges in a plurality of nozzle rows 10a and 10b in the head 1.

(Modification example 1)
Although the block diagram of FIG. 5 shows an example in which the drive waveform generation unit 402 is provided for each head, the drive waveform generation unit 402 may be shared by a plurality of heads instead of the head unit. Good. Even in that case, while the one discharge head is coloring the yarn, the other discharge heads are moved to replace the one nozzle row 10a and the other nozzle row 10b located on the yarn. It is possible to switch between the discharge operation for maintenance and the discharge operation for coloring in the discharge head of.

(Modification 2)
Alternatively, the drive waveform generation unit 402 may be provided for each of the nozzle rows 10a and 10b in one head. In this configuration, the drive waveform and the drive frequency can also be set for each nozzle row. For example, without generating a common drive waveform, for example, the drive waveform generator corresponding to one nozzle row generates a discharge waveform for coloring, and the drive waveform generator corresponding to the other nozzle row is empty. Separate waveforms are generated, such as generating drive waveforms for discharge. Therefore, the degree of freedom in setting the empty discharge is increased, and the effect of the empty discharge can be increased.

As the number of drive waveform generators and drive circuits increases, more appropriate control can be executed and the effect improves, but the cost increases due to the increase in the number of parts, so it is preferable to select appropriately according to the specifications and cost. Is.

The application timing of the waveform and the overall control will be described with reference to FIGS. 9 and 10.

<Timing chart>
FIG. 9 is a control timing chart according to the first embodiment.

In the plurality of nozzle rows 10a and 10b, the coloring operation is executed by the nozzle rows during the coloring operation (for example, the nozzle rows 10a in FIG. 3) arranged on the yarn (t1).

Note that FIG. 9 shows an example in which a coloring waveform is applied to the nozzle row 10a located on the yarn at the timing immediately after the start, but the nozzles are based on the yarn coloring data SD. A fine drive waveform is applied to the nozzles not used in row 10a. Further, when the heads of other colors discharge and the droplets are not discharged from the heads of that color, the fine drive waveform is applied to all the nozzle rows of the unused colors.

When the drive waveform of FIG. 8 is used, the coloring pulse P1 and the fine driving pulse P2 are used in the nozzle row 10a above the yarn based on the yarn coloring data SD.

The nozzle row 10b, which is not arranged on the yarn and does not perform the coloring operation, performs a fine drive operation.

When the drive waveform of FIG. 8 is used, the fine drive pulse P2 is selected from the drive waveform by the mask signal for all nozzles in the nozzle row 10b that does not exist on the thread, and is discharged from the nozzles. Perform a fine drive that vibrates (swings) the meniscus to the extent that it does not.

Until it is determined that the ejection becomes unstable in the nozzle row 10a during the coloring operation, the nozzle row 10a continues the coloring operation as it is, and the nozzle row 10b continues the fine drive operation.

When the head control unit 401 determines that the discharge becomes unstable (t2), the nozzle row 10b, which is not colored and is not located on the thread, switches from the fine drive operation to the maintenance operation by the empty discharge operation (t3). Since the empty ejection operation is performed on all the nozzles in the nozzle row 10b, the liquid is forcibly thickened even if the ink is thickened in the nozzles by waiting at a position other than the top of the thread. Is discharged to a region (collection surface 22 (empty discharge receiver)) that is not on the thread, and the inside of the nozzle is refreshed.

When the drive waveform of FIG. 8 is used, maintenance of the nozzle row 10b by empty ejection is performed by selecting and using the empty ejection pulse P3 by the mask signal. At this time, as shown in FIG. 8, the empty ejection pulse has a larger number of pulses and a larger amplitude than the coloring pulse, so that the number of droplets is larger than that of the coloring pulse. The thickened liquid can be effectively discharged.

Here, the discharge unstable signal output by the head control unit 401 is set to hi for an arbitrary period at the timing when any of the decap time comparison signal, the replacement time comparison signal, and the non-discharge period comparison signal becomes Hi. Become. For example, in t2, the discharge unstable signal becomes Hi at the timing when the decap time comparison signal becomes Hi, and in t6, the discharge unstable signal becomes Hi at the timing when the time comparison signal after replacement becomes Hi. At t10, an example is shown in which the discharge unstable signal becomes Hi at the timing when the non-discharge period comparison signal becomes Hi.

Then, the nozzle row 10b immediately after maintenance, which was not on the thread, is moved perpendicularly to the thread transport direction (t4⇒t5), the nozzle row 10b is placed on the thread, and then controlled based on the thread coloring data SD. , Make a coloring operation.

As a result, by detecting the unstable state of the nozzle row 10a (10b) located on the yarn and executing the coloring operation in advance, it is possible to stop the use before the abnormality occurs. At the same time, abnormal discharge can be prevented by using the nozzle row 10b (10a) which is located on a position other than the thread, waits by fine driving of all nozzles, and performs maintenance by empty discharge immediately before.

As described above, in the control of the present invention, during a predetermined period t3 to t4, t7 to t8, and t11 to t12 after the determination of discharge instability, one nozzle row discharges for coloring while the other nozzle row discharges. Since the empty discharge can be performed, the interval for the empty discharge becomes unnecessary, and the discharge for coloring can be stabilized without lowering the productivity.

<Flowchart>
FIG. 10 is a control flowchart relating to the replacement of nozzle rows and the waveform to be applied in the first embodiment. The control flow of the present invention will be described with reference to FIG. 10, FIGS. 3 and 9.

This flow starts when the coloring request is received, and in S1, all the nozzle rows 10a and 10b are decapped in response to the occurrence of the coloring request, and the decapping elapsed time counting unit 501 starts counting the decap time. (Fig. 9, t0).

In S2, the head is moved so that the nozzle row (for example, 10a) that executes the coloring operation is on the yarn (FIG. 9, t0⇒t1).

In S3, the coloring operation is executed by applying a coloring pulse or a fine driving pulse based on the thread coloring data SD to the piezoelectric elements 13a to 131x of the nozzle row 10a that have reached the yarn. At this time, the non-ejection period counting unit 505 for each nozzle counts the non-ejection period of each nozzle of the nozzle row 10a on the thread during the ejection operation (FIG. 9, t1).

Further, during the coloring operation, one of the nozzle rows 10a is not on the thread, and the nozzle row 10b which is not performing the coloring operation performs a fine drive operation. Then, the coloring operation and the fine drive operation are continued as they are in the nozzle rows 10a and 10b until the nozzle row 10a during the coloring operation is determined to be "unstable" (FIG. 9, t1⇒t3).

In S4, the head control unit 401 determines whether or not the ejection becomes unstable in the nozzle row 10a during the coloring operation. In this determination, the head control unit 401 determines that the discharge becomes unstable at the timing when either the decap time comparison signal or the non-discharge period comparison signal becomes Hi (FIGS. 9, t2).

When it is determined that the ejection becomes unstable in the nozzle row 10a during the coloring operation (Yes in S4), in S5, the piezoelectric elements 13a to 13x corresponding to all the nozzles of the nozzle row 10b that are not on the thread are slightly driven. The nozzle row 10b is maintained by switching from the nozzle P2 and applying the empty ejection pulse P3 to execute the empty ejection discharge (FIG. 9, t3⇒t5). This prepares the nozzle row 10b for use in the coloring operation.

When the empty discharge operation of the nozzle row 10b elapses for a predetermined time, in S6, the head is moved perpendicularly to the thread transport direction while continuing the empty discharge operation of the nozzle row 10b, and the nozzle row for which maintenance was performed immediately before. 10b is placed on the thread (Fig. 9, t4⇒t5). At that time, the replacement elapsed time counting unit 503 starts counting the elapsed time after replacement (FIGS. 9, t5).

In S7, the piezoelectric element 13 of each nozzle of the nozzle row 10b, which is arranged on the thread by replacement, is switched from the empty discharge pulse P3, and the coloring pulse P1 or fine drive is performed based on the thread coloring data SD. The coloring operation is executed by applying the pulse P2. At this time, the non-ejection period counting unit 505 for each nozzle counts the non-ejection period of each nozzle of the nozzle row 10b on the yarn during the ejection operation based on the thread coloring data SD (FIGS. 9, t5).

Further, while the other nozzle row 10b is in the coloring operation, the nozzle row 10a, which is not on the thread and is not performing the coloring operation, performs a fine drive operation. In the nozzle row 10a, which had been performing the coloring operation until just before, when the head 1 starts to move so that the nozzle row 10a comes off from the top of the thread, the fine drive pulse P2 is applied by switching from the coloring pulse P1. Then, the fine drive operation may be started (FIG. 9, t4).

Then, when the instruction to end the coloring operation is generated in S8, the head 1 is moved to the position of the cap 21 in S10 to end.

On the other hand, when the instruction to end the coloring operation is not generated, the coloring operation in the nozzle row 10b and the nozzle row 10a are performed until the nozzle row 10b during the coloring operation is determined to be "unstable" in S9 (FIGS. 9, t6). The fine drive operation is continued as it is (Fig. 9, t5 ⇒ t7).

The determination of the head control unit 401 in S9 after the replacement determines that the discharge becomes unstable at the timing when either the replacement time comparison signal or the non-discharge period comparison signal becomes Hi (FIG. 9, FIG. t6, t10).

Then, when the nozzle row 10b during the coloring operation is determined to be "unstable" in S9, the nozzle row 10b returns to the front of S5 and an empty discharge operation is performed on the nozzle row 10a in S5 (FIG. 9, t7⇒t9). , S6 moves the position of the head and arranges the nozzle row 10a on the thread (FIG. 9, t8⇒t9), in S7, the nozzle row 10a is colored (FIG. 9, t9), and the nozzle row 10b is slightly driven. The operation (FIG. 9, t8) is executed.

The above steps S5, S6, S7, and S9 are repeated in S8 while exchanging the nozzle rows 10a and 10b to be used until the coloring operation end instruction is received.

As described above, since the maintenance discharge and the coloring discharge can be performed in parallel for each nozzle row at the same time, the empty discharge can be performed even during the coloring, and the discharge stability is improved.

In the present invention, as described above, in a plurality of nozzle rows, one nozzle row is discharged to the thread, and the other nozzle row is empty-discharged to the collection surface 22 (empty discharge receiver) other than the thread. The linear or strip-shaped ejected medium such as a thread to be ejected needs to be a medium having a width narrower than the distance between rows of a plurality of nozzle rows and being thin.

Since the head moving unit 140 for moving the position of the discharge head 1 is provided for each head, the replacement timing can be changed for each head. For example, it is possible to replace the nozzle row on the thread in the head of a color that is not used even while the nozzle is being discharged onto the thread from another head.

<Second Embodiment>
In the above first embodiment, the time during which the ejection at the nozzle becomes unstable is counted and predicted based on the time and the thread coloring data SD in the head control unit 401, but the state inside the nozzle is directly measured. You may.

FIG. 11 is a control block diagram of a portion related to liquid discharge, head movement, cap raising / lowering, and nozzle state detection in the liquid discharge device according to the second embodiment of the present invention.

In the present embodiment, the head 1A is provided with viscometers 151 to 15x as means for directly measuring the state inside the nozzle 11. Viscometers 151 to 15x are provided in all pressure chambers that communicate with the nozzle 11 and are pressurized by the piezoelectric elements 13 (13a to 13x). The viscometer 15 is configured to detect the ink viscosity in each pressure chamber.

In the present embodiment, the head control unit 401A grasps the state of the nozzle 11 based on the ink viscosity in the pressure chamber detected by the viscometer 15, so that the timing matches the actual ink state in the nozzle 11. It is possible to determine that "discharge is unstable", shift the nozzle row not located on the thread to maintenance of empty discharge, and replace the nozzle row to be used.

Here, in the present invention, maintenance is performed shortly before the ejection becomes unstable and becomes completely abnormal. Therefore, in the head control unit 401A of the present embodiment, the ink viscosity becomes high and shortly before the abnormality becomes abnormal. The "viscosity that may become abnormal" is set to the threshold value for determining that "discharge is unstable".

In this configuration, the nozzle rows can be replaced according to the current nozzle situation, and the frequency of replacement can be minimized.

<Third Embodiment>
FIG. 12 is a control block diagram of a portion related to liquid discharge, head movement, cap raising / lowering, and nozzle state detection in the liquid discharge device according to the third embodiment of the present invention.

In the present embodiment, the head 1B is provided with the piezoelectric element connection substrate 16 and the residual vibration detection unit 17 as means for directly measuring the state inside the nozzle. Specifically, the piezoelectric element connecting substrate 16 is provided corresponding to all the pressure chambers, and the ink viscosity is detected by the residual vibration detecting unit 17 based on the damped vibration detected by the piezoelectric element connecting substrate 16. In this embodiment, the head driver 410B is provided inside the head 1B.

FIG. 13 is an operation conceptual diagram showing the residual vibration detected in the third embodiment.

As shown in FIG. 13A, when the drive waveform generated by the drive waveform generator 402 is applied to the piezoelectric element 13 (specifically, the electrode of the piezoelectric element connection substrate 16), the piezoelectric element 13 is subjected to. , Expands and contracts. An elastic force acts from the piezoelectric element 13 to the ink in the pressure chamber 27 via the diaphragm 30, and a pressure change occurs in the pressure chamber 27, so that ink droplets are ejected from the nozzle 11. For example, the falling operation of the drive waveform lowers the pressure in the pressure chamber 27, and the rising operation of the drive waveform raises the pressure in the pressure chamber 27.

As shown in FIG. 13B, after the drive waveform is applied to the piezoelectric element 13 (after the ink droplets are ejected), residual pressure vibration is generated in the ink in the pressure chamber 27, and the ink in the pressure chamber 27 is in the pressure chamber 27. The residual pressure wave propagates from the ink to the piezoelectric element 13 via the vibrating plate 30. The residual vibration waveform of the residual pressure wave becomes a damped vibration waveform. As a result, a residual vibration voltage is induced in the piezoelectric element 13 (specifically, the electrode of the piezoelectric element connecting substrate 16). The residual vibration detection unit 17 detects the residual vibration voltage and outputs the detection result to the head control unit 401B as the output of the residual vibration detection unit.

In the present embodiment, the head control unit 401B calculates the ink viscosity based on the residual vibration detected by the residual vibration detection unit 17, and grasps the ink state based on the calculated ink viscosity to obtain the ink state in the actual nozzle. It is possible to determine that the ejection is unstable at the timing corresponding to the ink state of the above, shift to maintenance, and replace the nozzle row to be used.

In the first embodiment, it was determined that the ejection from the nozzle becomes unstable based on the time and the thread coloring data, and in the second embodiment and the third embodiment, based on the nozzle state. It may be determined that the ejection from the nozzle becomes unstable based on both the thread coloring data and the measured nozzle state.

<Fourth Embodiment>
Further, as another method for determining "discharge from the nozzle is unstable", the landing condition on the yarn may be detected after the yarn is actually ejected. FIG. 14 is a schematic explanatory view of an example of a coloring / embroidery system including a liquid discharge device equipped with a sensor for detecting a landing state on a thread according to a fourth embodiment of the present invention.

The sensor 107 of the present embodiment is provided so as to be located behind the head 1 of the liquid applying portion 103 in the transport direction in order to detect the formed inspection pattern.

In the liquid discharge device 100A shown in FIG. 14A, an example in which the sensor 107 is provided immediately after the liquid application unit 103 is shown. Further, if the sensor is behind the liquid applying unit 103, the position of the sensor 107 does not have to be immediately after the liquid applying unit 103.

Therefore, as in the liquid discharge device 100B shown in FIG. 14B, the sensor 107B may be behind the fixing unit 104 and the post-processing unit 105. Alternatively, although not shown, it may be between the fixing unit 104 and the post-processing unit 105.

In the fourth embodiment, a predetermined inspection pattern formed on the thread 101 is automatically detected by providing the sensor 107 on the rear stage side of the head 1 in the transport path of the thread 101 which is a linear object. be able to.

In addition, in FIGS. 18A and 18B, when the photosensor is adopted as the sensor 107, since it is installed only on the upper side, the light emitting portion that irradiates the linear object with light and the reflected light are detected. Although an example of using a reflection type photosensor in which the light receiving part is integrated is shown, a transmission type photosensor in which a light emitting part and a light receiving part are separately provided on the upper side and the lower side of the thread transport path may be used. ..

Alternatively, the sensor 107 may be composed of an image sensor (camera).

In the present embodiment, the head control unit detects the ejection / non-ejection of each nozzle and the size of the ejected droplets based on the landing state on the thread detected by the sensor 107, and based on the ejection status, ink By grasping the state (ink clogging), it is determined that the ejection is unstable at the required timing according to the actual landing state on the thread. Then, based on the determination, it is possible to shift to maintenance and replace the nozzle row to be used.

In the first embodiment, it is based on the time and the thread coloring data, in the second embodiment and the third embodiment, it is based on the nozzle state, and in the fourth embodiment, it is based on the detection result of the landing droplet on the thread. Therefore, it was determined that the ejection from the nozzle became unstable, but two or three of the time and thread coloring data, the measured nozzle state, and the detected droplet landing state on the thread were obtained. In combination, it may be determined that the discharge from the nozzle becomes unstable.

<Other liquid discharge devices>
Next, another example of the coloring apparatus according to the embodiment of the present invention will be described with reference to FIG. FIG. 15 is a schematic explanatory view of an example of a coloring system equipped with a liquid discharge device according to an embodiment of the present invention.

In the coloring system 2000, the embroidery head 106 in the coloring / embroidery apparatus 1000 shown in FIG. 1 is a take-up reel 110 that winds up the colored thread 101.

The coloring system 2000 supplies the thread 101 from the supply reel 102, discharges and imparts a liquid of a required color from the liquid applying unit 103, colors the thread 101 to a target color, and winds the colored thread 101 into a winding reel. Wind up to 110.

Also in the present coloring system 2000, it is determined that the ejection from the nozzle row in the coloring operation becomes unstable by the control using the first embodiment, the second, the third embodiment, and the fourth embodiment described above. , Maintenance discharge and coloring discharge can be performed at the same time for each nozzle row of a plurality of nozzles. Therefore, the empty discharge can be performed even during the coloring, so that the discharge stability is improved.

Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described embodiments and examples. In addition, the present invention can be variously modified or modified in light of the appended claims.

1 (1K, 1C, 1M, 1Y) head (discharge head)
2 Maintenance unit 10a, 10b Nozzle row 11 Nozzle 20 (20K, 20C, 20M, 20Y) Maintenance unit 21 (21K, 21C, 21M, 21Y) Cap 22 Recovery surface (empty discharge receiver)
100 Liquid discharge device 101 Thread (linear object, discharge medium)
103 Liquid application unit 303 Head position control unit 306 Cap elevating control unit 401, 401A, 401B Head control unit 402 Drive waveform generation unit 403 Waveform data storage unit 404 Discharge timing generation unit 405 Rotary encoder 410, 410B Head driver 501 Decapping elapsed time Counting unit 502 Decapping elapsed time comparison unit 503 Elapsed time after replacement Counting unit 504 Elapsed time after replacement 505 Nozzle-by-nozzle non-ejection period counting unit 506 Nozzle non-ejection period comparison unit 507 Threshold storage unit 508 Nozzle row instability determination unit 509 Empty discharge operation indicator 100A, 100B Liquid discharge device 108 Conveyor roller (conveyor unit)
109 Conveying roller (conveying part)
1000 Coloring / embroidery equipment 2000 Coloring system

Japanese Patent No. 6241078 Japanese Unexamined Patent Publication No. 2010-09950 Japanese Unexamined Patent Publication No. 2002-200381

Claims (11)

A transport unit that transports the medium to be discharged and
A discharge head provided with a plurality of nozzle rows in which a plurality of nozzles are arranged in a row in parallel with the transport direction of the discharge medium.
It has a control unit that controls the ejection of each nozzle row of the ejection head, and has.
A liquid discharge device capable of assigning a discharge operation for maintenance and a discharge operation for coloring to each nozzle row of the plurality of nozzle rows and simultaneously executing a discharge operation for maintenance and a discharge operation for coloring. .. The liquid discharge device according to claim 1, wherein the discharge medium is a linear or strip-shaped medium having a width narrower than the distance between rows of a plurality of nozzle rows and continuous in the transport direction. A head moving portion that moves the discharge head in a direction perpendicular to the transport direction of the discharge medium, and a head moving portion.
Has multiple discharge heads
The head moving unit can move the plurality of discharge heads for each discharge head.
While one discharge head is performing the coloring operation on the discharge medium, the other discharge head is moved to replace one nozzle row located on the discharge medium with another nozzle row, whereby the other discharge head is replaced with another nozzle row. The liquid discharge device according to claim 1 or 2, wherein the discharge operation for maintenance and the discharge operation for coloring can be switched. It has a drive waveform generator that generates a drive waveform.
The discharge head includes a pressure generating element that applies pressure to the liquid in each nozzle constituting the nozzle row.
In the nozzle row located above the discharge medium, the control unit applies a driving waveform for coloring to adhere the liquid onto the discharge medium for each nozzle in the nozzle row based on the coloring data. By applying a fine drive waveform for applying to the generating element or swinging the meniscus of the nozzle to the pressure generating element, the ejection operation for coloring is executed.
In the nozzle row not located above the discharge medium, a fine drive operation of applying a fine drive waveform for swinging the meniscus of the nozzle to the pressure generating element in all nozzles, or a fine drive operation in all nozzles of the discharge medium. The liquid discharge device according to claim 3, wherein an empty discharge operation of applying a drive waveform for empty discharge to discharge a liquid to a region other than the above to the pressure generating element can be executed. The control unit determines whether or not ejection from at least a part of the nozzles becomes unstable in the nozzle row that executes the ejection operation for coloring, which is located on the ejected medium.
Until it is determined that the discharge is unstable, in the nozzle row that is not located on the discharge medium, the fine drive operation is executed in all the nozzles.
When it is determined that the discharge is unstable, in the nozzle row not located on the discharge medium, after the empty discharge operation is executed in all the nozzles, the nozzle row in which the empty discharge operation is executed is the subject. The liquid discharge device according to claim 4, wherein the discharge head is moved so as to be located above the discharge medium. The control unit is located on the ejected medium and counts the non-ejection period of the non-ejection nozzles in the nozzle row that executes the ejection operation for coloring, and when the non-ejection period is equal to or longer than a predetermined time, The liquid discharge device according to claim 5, wherein it is determined that the discharge from the nozzle row including the nozzle becomes unstable. The control unit counts the elapsed time since the coloring start instruction or the previous movement of the ejection head, and when the elapsed time exceeds a predetermined time, the nozzle row currently located on the ejected medium is used. The liquid discharge device according to claim 5, wherein it is determined that the discharge of the liquid is unstable. The discharge head has a nozzle state detecting means for determining the state of the liquid inside each nozzle of the nozzle row.
When there is a risk that the nozzle state in the liquid chamber communicating with the detected nozzle may become abnormal by the nozzle state detecting means, the control unit is currently located on the ejected medium including the nozzle. The liquid discharge device according to claim 5, wherein it is determined that the discharge from the nozzle row is unstable. One drive waveform generated by the drive waveform generation unit includes a pulse for performing a discharge operation for coloring and a pulse for performing a discharge operation for maintenance.
The liquid discharge device according to any one of claims 4 to 8, wherein pulses for different purposes are selected from the drive waveforms for the plurality of nozzle trains and used. The discharge head has a drive waveform generation unit for each nozzle row.
The liquid discharge device according to any one of claims 1 to 8, wherein pulses for different purposes are generated and used for each nozzle row. This is a discharge control method for liquid discharge devices.
The liquid discharge device includes a transport unit for transporting the discharge medium and a discharge head provided with a plurality of nozzle rows parallel to the transport direction of the discharge medium.
A step of executing a ejection operation for coloring from one nozzle row to the ejected medium, and
A discharge control method in a liquid discharge device having a step of executing an empty discharge operation for maintenance from another nozzle row at the same time as a step of executing the discharge operation for coloring.

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