JP2016022655A - Liquid jet head, liquid jet device, and signal processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid jet head capable of reducing the volume of the data for correcting a discharge timing and capable of reliably inputting the data in a short time.SOLUTION: A liquid jet head 1 comprises a nozzle array 2 in which plural nozzles N are arranged in a reference direction K, and an actuator part 3 to which a driving signal Ds corresponding to each nozzle N is input and which discharges droplets from the nozzle N. The driving signal Ds corresponding to the nozzle N located in an end part area EA of the nozzle array 2 has a time difference Δt in a droplet discharge timing with respect to the driving signal Ds corresponding to the nozzle N located in a central area CA of the nozzle array 2. As the nozzles N located in the end part area EA approach the end of the nozzle array 2, the time difference Δt of the corresponding driving signal Ds broadens out.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid ejecting head, a liquid ejecting apparatus, and a signal processing method for ejecting and recording droplets on a recording medium.

  In recent years, an ink jet type liquid ejecting head has been used in which ink droplets are ejected onto recording paper or the like to record characters and figures, or a liquid material is ejected onto the surface of an element substrate to form a functional thin film. In this method, a liquid such as ink or a liquid material is guided from a liquid tank to a pressure chamber via a supply pipe, pressure is applied to the liquid filled in the pressure chamber, and the liquid is discharged from a nozzle communicating with the pressure chamber. When the liquid is ejected, the liquid ejecting head or the recording medium is moved to record characters or figures, or a functional thin film or a three-dimensional structure having a predetermined shape is formed.

  In this type of liquid ejecting head, a gap is provided between the liquid ejecting head for ejecting liquid droplets and the recording medium for recording the ejected liquid droplets, and the liquid ejecting head and the recording medium are relatively moved. Record while. Since the liquid ejecting head ejects liquid droplets from a plurality of nozzles at the same timing, the position of the liquid droplets recorded on the recording medium is shifted if there is variation in the ejection speed of the liquid droplets ejected between the nozzles. The recording quality is reduced.

  In Patent Document 1, in order to solve the above problem, when a droplet is ejected from each nozzle, the ejection timing is adjusted according to the inherent ejection speed of each nozzle, and the droplet lands on the recording medium. Reduce variation in landing position. FIG. 11 is a block diagram of a liquid ejecting apparatus described in Patent Document 1 (FIG. 2). The liquid ejecting apparatus includes an inkjet head 100 (liquid ejecting head) that ejects droplets, a drive circuit 400 that supplies an ejection drive signal to the inkjet head 100, and a variable time adjustment circuit 510 that supplies a drive signal to the drive circuit 400. And a setting unit 600 for setting a delay time of the discharge timing. The inkjet head 100 includes a nozzle 200 that ejects droplets and a piezoelectric element 300 that corresponds to the nozzle 200 and ejects droplets from the nozzle 200.

  The variable time adjustment circuit 510 adjusts the ejection timing of the driving signal input corresponding to each driving circuit 400 based on the setting value of the setting unit 600 and outputs the adjusted timing to the driving circuit 400. That is, the variable time adjustment circuit 510 provides a large delay time for the drive signal corresponding to the nozzle 200 having a high droplet discharge speed, and a small delay time for the drive signal corresponding to the nozzle 200 having a low droplet discharge speed. Is provided. Thereby, the droplets ejected from the nozzles 200 that should be ejected at the same timing can be landed at the same point in the moving direction in which the recording medium relatively moves. Here, the discharge speed of the liquid droplets discharged from each nozzle 200 can be checked in advance or periodically, and the delay time of each nozzle 200 can be set from the setting unit 600 according to each discharge speed.

  Patent Document 2 describes a printer that drives a plurality of ejection actuators of a head cartridge having a line head and ejects liquid droplets from nozzles that communicate with each of the plurality of actuators. Due to variations in the bonding accuracy between the head substrate and the holding member, the positional accuracy of the head discharge port, thermal deformation during assembly, and the effects of stress, the droplets discharged from each nozzle are perpendicular to the recording medium. In some cases, the liquid is not discharged, or the discharge speed of the liquid droplets discharged from the nozzle is too slow or too fast. Therefore, the position where the ejected droplets land on the recording medium is shifted, and the recording quality is deteriorated.

  Therefore, a time adjustment unit is provided between the head drive circuit and the head cartridge, and the timing of the drive voltage supplied from the head drive circuit to the head cartridge is adjusted by the time adjustment unit. Specifically, the control unit acquires control parameter information set in advance for each head cartridge. The control parameter information includes the discharge speed and discharge angle of the droplets discharged from the nozzles, and the control unit calculates the adjustment time ΔT corresponding to all the nozzles from the control parameter information. The time adjustment unit acquires information about the adjustment time ΔT from the control unit, and supplies a voltage whose timing is adjusted based on the adjustment time ΔT to each of all the discharge actuators corresponding to all the nozzles. Thereby, it can correct | amend so that the landing position of a droplet may be shifted for every nozzle.

JP-A-4-282255 JP 2002-144543 A

  In the liquid ejecting apparatuses disclosed in Patent Documents 1 and 2, the droplet ejection speed is adjusted for all nozzles that eject droplets. Therefore, an adjustment time for adjusting the ejection timing is set in the drive signal for all nozzles. Specifically, the dispersion of droplet landing positions is measured in advance for all nozzles. Based on the measurement result of the landing position, the adjustment time for adjusting the discharge timing is obtained for all the nozzles, and the adjustment time is set for each of the drive signals for discharging droplets from each nozzle. As the number of nozzles increases, the number of landing position measurements increases and the data amount of control parameter information that determines the adjustment time also increases. Therefore, the measurement becomes complicated, and a storage area for control parameter information is newly required. In addition, input mistakes in control parameter information are likely to occur.

  The liquid jet head of the present invention includes a nozzle row in which a plurality of nozzles are arranged in a reference direction, and an actuator unit that inputs a driving signal corresponding to each of the nozzles and discharges droplets from the nozzle, The drive signal corresponding to the nozzle located in the end region of the nozzle row has a time difference in the timing at which droplets are ejected with respect to the drive signal corresponding to the nozzle located in the central region of the nozzle row, and the end portion Among the nozzles located in the region, the time difference of the drive signals corresponding to the nozzles close to the end of the nozzle row is larger than the time difference of the drive signals corresponding to the nozzles close to the central region.

  In addition, a droplet discharged from the nozzle located in the end region has a speed difference with respect to a droplet discharged from the nozzle located in the central region, and the nozzle located in the end region has a difference in speed. Among these, the speed difference of the droplets ejected from the nozzles close to the end of the nozzle row is larger than the speed difference of the droplets ejected from the nozzles close to the central region.

  The end region includes one end region and the other end region of the nozzle row, and is located in the one end region with the center in the reference direction of the nozzle row as a central point. When the nozzle and the nozzle located in the other end region are located at a symmetrical point with respect to the central point, the time difference between the drive signals corresponding to the two nozzles located at the symmetrical point is equal.

  Further, when the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the nozzle row toward the end, the time difference of the drive signal corresponding to the nozzle located at the point of the coordinate x Is expressed by a linear function of coordinates x.

  Further, when the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the nozzle row toward the end, the time difference of the drive signal corresponding to the nozzle located at the point of the coordinate x Is expressed by a quadratic function of coordinates x.

  The liquid ejecting head of the present invention includes a nozzle row in which a plurality of nozzles are arranged in a reference direction, and an actuator unit that inputs a driving signal corresponding to the nozzles and discharges liquid droplets from the nozzles. When a continuous region is formed in which the nozzles ejecting droplets are continuous in the reference direction, a drive signal corresponding to the nozzle located at the center of the continuous region or in the vicinity thereof is applied to an end region of the continuous region. The drive signal corresponding to the nozzle located has a time difference in the discharge timing of droplets, and among the nozzles located in the end region, the drive corresponding to the nozzle close to or near the center of the continuous region The time difference of the drive signal corresponding to the nozzle near the end of the continuous region is larger than the time difference of the signal.

  In addition, a droplet discharged from the nozzle located in the end region has a speed difference with respect to a droplet discharged from the nozzle located in the center or the vicinity thereof, and the droplet located in the end region Among the nozzles, the speed difference of the droplets discharged from the nozzle near the end of the continuous region is larger than the speed difference of the droplets discharged from the nozzle near the center of the continuous region or the vicinity thereof. .

  In addition, the image forming apparatus further includes a drive unit that acquires image data and generates the drive signal, and the drive unit detects the continuous region in which the nozzle that discharges droplets from the image data in one cycle is continuous in the reference direction. It was decided to.

  In addition, the end region includes one end region and the other end region of the continuous region, and the center of the continuous region in the reference direction is a center point, and the end region is located in the one end region. When the nozzle and the nozzle located in the other end region are located at a symmetrical point with respect to the central point, the time difference between the drive signals corresponding to the two nozzles located at the symmetrical point is equal.

  Further, when the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the continuous region toward the end, a drive signal for discharging droplets from the nozzle located at the point of the coordinate x The time difference is expressed by a linear function of the coordinate x.

  Further, when the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the continuous region toward the end, a drive signal for discharging droplets from the nozzle located at the point of the coordinate x The time difference is expressed by a quadratic function of coordinates x.

  The liquid ejecting apparatus according to the aspect of the invention includes the liquid ejecting head, a moving mechanism that relatively moves the liquid ejecting head and the recording medium, a liquid supply pipe that supplies liquid to the liquid ejecting head, and the liquid And a liquid tank for supplying the liquid to the supply pipe.

  The signal processing method of the present invention includes a step of specifying a set value, a step of specifying an end region of a nozzle row in which a plurality of nozzles are arranged in a reference direction based on the set value, and a position in the end region A step of calculating a time difference for determining a discharge timing of droplets discharged from the nozzle according to a position of the nozzle, a step of generating a drive signal in which the time difference is set, and a step of supplying the drive signal to an actuator unit And so on.

  The end region includes one end region and the other end region of the nozzle row, and is located in the one end region with the center in the reference direction of the nozzle row as a central point. When the nozzle and the nozzle located in the other end region are located at a symmetrical point with respect to the central point, in the step of generating the drive signal, droplets are ejected from the two nozzles located at the symmetrical point The same time difference is set for the driving signals to be set.

  Further, in the step of calculating the time difference, when the position of the nozzle located in the end region is represented by a coordinate x that increases from the center to the end of the nozzle row, the liquid from the nozzle located at the coordinate x is liquidated. The time difference when the droplet is ejected is calculated by a linear function of the coordinate x.

  Further, in the step of calculating the time difference, when the position of the nozzle located in the end region is represented by a coordinate x that increases from the center to the end of the nozzle row, the liquid from the nozzle located at the coordinate x is liquidated. The time difference when the droplet is ejected is calculated by a quadratic function of the coordinate x.

  In the signal processing method of the present invention, a step of specifying a set value, a step of acquiring image data, and a nozzle array in which a plurality of nozzles are arranged in a reference direction, droplets are ejected from the acquired image data of one cycle. Detecting a continuous region in which the nozzles are continuous, identifying an end region in the continuous region based on the set value, and depending on the position of the nozzle located in the end region, The method includes a step of calculating a time difference that determines a discharge timing of droplets discharged from the nozzle, a step of generating a drive signal in which the time difference is set, and a step of supplying the drive signal to an actuator unit.

  The end region includes one end region and the other end region of the nozzle row, and is located in the one end region with the center in the continuous region of the nozzle row as a central point. When the nozzle and the nozzle located in the other end region are located at a symmetrical point with respect to the central point, in the step of generating the drive signal, droplets are ejected from the two nozzles located at the symmetrical point The drive signals to be made are equal to each other.

  Further, in the step of calculating the time difference, when the position of the nozzle located in the end region is expressed by a coordinate x that increases from the center of the continuous region toward the end, the liquid from the nozzle located at the coordinate x is liquidated. The time difference when the droplet is ejected is calculated by a linear function of the coordinate x.

  Further, in the step of calculating the time difference, when the position of the nozzle located in the end region is expressed by a coordinate x that increases from the center of the continuous region toward the end, the liquid from the nozzle located at the coordinate x is liquidated. The time difference when the droplet is ejected is calculated by a quadratic function of the coordinate x.

  The liquid ejecting head of the present invention includes a nozzle row in which a plurality of nozzles are arranged in a reference direction, and an actuator unit that inputs a driving signal corresponding to each of the nozzles and ejects droplets from the nozzle, The drive signal corresponding to the nozzle located in the end region of the nozzle row has a time difference in the timing of ejecting the liquid droplets, and the drive signal corresponding to the nozzle located in the end region of the nozzle row The time difference between the drive signals corresponding to the nozzles close to the end of the nozzle row is larger than the time difference between the drive signals corresponding to the nozzles close to the central region. As a result, a time difference is provided in the ejection timing for the nozzles located in the end region that is a part of the nozzle row, and therefore the amount of data for correcting the ejection timing can be reduced. Further, since the amount of data is small, it is possible to input data reliably in a short time.

1 is a configuration diagram of a liquid jet head according to a first embodiment of the present invention. FIG. 5 is a diagram for explaining the ejection characteristics of the liquid droplets of the liquid jet head according to the first embodiment of the present invention. FIG. 6 is a configuration diagram of a liquid jet head according to a second embodiment of the present invention. It is a flowchart showing the signal processing method which concerns on 3rd embodiment of this invention. FIG. 6 is a configuration diagram of a liquid jet head according to a fourth embodiment of the present invention. FIG. 10 is a configuration diagram of a liquid jet head according to a fifth embodiment of the present invention. FIG. 10 is a configuration diagram of a liquid jet head according to a sixth embodiment of the present invention. It is a flowchart showing the signal processing method which concerns on 7th embodiment of this invention. FIG. 10 is an exploded perspective view of a head portion of a liquid jet head according to an eighth embodiment of the present invention. FIG. 10 is a schematic perspective view of a liquid ejecting apparatus according to a ninth embodiment of the present invention. It is a block diagram of a conventionally well-known liquid ejecting apparatus.

(First embodiment)
FIG. 1 is a configuration diagram of a liquid jet head 1 according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining the droplet ejection characteristics of the liquid jet head 1 according to the first embodiment of the present invention. As shown in FIG. 1, the liquid jet head 1 includes a nozzle array 2 in which a plurality of nozzles N ₁ to N _n are arranged in the reference direction K, the drive signal Ds ₁ to DS _n corresponding to the nozzle N ₁ to N _n ( n is a positive integer) and is provided with a head unit 11 including an actuator unit 3 that discharges droplets from nozzles N _{1 to} N _n . The actuator unit 3 comprises an actuator A ₁ to A _n, the actuator A ₁ to A _n can eject droplets from the corresponding nozzles N ₁ to N _n. The nozzles N _{1 to} N _{n in the} nozzle row 2 are arranged linearly at equal intervals.

The nozzle row 2 and the actuator unit 3 constitute a head unit 11. The head unit 11 further includes a pressure chamber 9 and a liquid chamber 10 for supplying a liquid to each pressure chamber 9. The actuator unit 3 includes a piezoelectric body (not shown) that deforms the side surface of each pressure chamber 9 and an electrode (not shown) that deforms the piezoelectric body by applying an electric field. Each actuator A ₁ to A _n corresponding to the nozzles N ₁ to N _n are integrally formed.

The nozzle row 2 includes a central area CA and one and other end areas EA1 and EA2. Each drive signal Ds _{m + 1 to} Ds _nm corresponds to each nozzle N _{m + 1 to} N _nm (m is a positive integer not less than 1 and not more than n / 2) located in the central area CA of the nozzle row 2. To do. The drive signals Ds _{1 to} Ds _m , Ds _{n-m +} are applied to the nozzles N _{1 to} N _m and N _{n-m + 1 to} N _n located in one and other end regions EA1 and EA2 of the nozzle row 2, respectively. _{1 ~Ds n} correspond. Each drive signal Ds _m + 1 the drive signals to _{~Ds nm Ds 1 ~Ds m, Ds} nm + 1 ~Ds n each time difference Delta] t ₁ to timing for ejecting droplets ~Δt _m, Δt _{nm +1 to} Δt _n . Of the nozzles N located in one and the other end areas EA1 and EA2, the nozzle N close to the end of the nozzle row 2 corresponds to the time difference Δt of the drive signal Ds corresponding to the nozzle N close to the center area CA. The time difference Δt of the drive signal Ds is large. Specifically, among the nozzles N _{1 to} N _m and N _{n−m + 1 to} N _n located in the one and other end regions EA1 and EA2, the nozzle row 2 is close to one end and the other end. The nozzle N has a larger time difference Δt of the corresponding drive signal Ds. That is, Δt _m <Δt _m-1 <... <Δt ₂ <Δt ₁ and Δt _{n-m + 1} <Δt _{n-m + 2} <... <Δt _n-1 <Δt _n Yes.

  Note that setting the central area CA is not essential in the liquid jet head 1 of the present invention. The central area CA may not be set, and only one and the other end areas EA1 and EA2 may be used. Further, the end area EA may be provided with only one end area EA1 of the nozzle row 2 or only the other end area EA2. In the case of the first embodiment, for example, the number n of nozzles N is 500, and the number m of nozzles N located in one or the other end region EA1, EA2 can be about 10.

Here, the liquid ejecting head 1 according to the first embodiment is configured such that one end and the other end of the nozzle row 2 are applied to droplets ejected from the nozzles N _{m + 1 to} N _nm located in the central area CA of the nozzle row 2. The droplets ejected from the nozzles N _{1 to} N _m and N _{n−m + 1 to} N _n located in the partial areas EA1 and EA2 have a speed difference. Of the nozzles N _{1 to} N _m and N _{n−m + 1 to} N _n located in the one and other end regions EA1 and EA2, the nozzle N closer to one end and the other end of the nozzle row 2 The speed difference is large. That is, V _m <V _where V _{1 to} V _m and V _{n-m + 1 to} V _n are the discharge speeds of the droplets discharged from the nozzles N _{1 to} N _m and N _{n-m + 1 to} N _n , respectively. _{m-1 <··· <V 2} <V 1, and has become a _{V n-m + 1 <V} n-m + 2 <··· <V n-1 <V n.

2, the same drive signal Ds when given concurrently to the actuator A ₁ to A _n, impact site Z ₁ to Z _n in which the droplets discharged from the nozzles N ₁ to N _n is landed on the recording medium Is shown schematically. The recording medium moves relative to the liquid ejecting head 1 in the + z direction orthogonal to the reference direction K. That is, the liquid ejecting head 1 is stationary and the recording medium moves in the + z direction, or the liquid ejecting head 1 is moved in the −z direction and the recording medium is stationary. Therefore, droplets ejected from the nozzle N having a high ejection speed land on the + z side, and droplets ejected from the nozzle N having a low ejection speed land on the −z side. That is, the droplets ejected from the nozzles N located in one and the other end regions EA1 and EA2 have a landing point Z on the + z side rather than the droplets ejected from the nozzle N located in the central region CA. Become. On the contrary, when the recording medium moves relative to the liquid ejecting head 1 in the −z direction orthogonal to the reference direction K, for example, the liquid ejecting head 1 is stationary and the recording medium is −z. When the liquid ejecting head 1 moves in the direction or the liquid ejecting head 1 moves in the + z direction and the recording medium is stationary, the liquid ejected from the nozzle N having a high ejection speed is ejected to the −z side. The liquid droplets discharged from the slow nozzle N land on the + z side. That is, the droplet Z ejected from the nozzle N located in one and the other end regions EA1 and EA2 is closer to the −z side than the droplet ejected from the nozzle N located in the central region CA. It becomes.

Therefore, a delay time of the time difference Δt is provided in the ejection timing of the drive signal Ds corresponding to the nozzles N located in the one and other end regions EA1 and EA2, and the nozzle N closer to the end of the nozzle row 2 has this time difference Δt. Set a large delay time. Thereby, it is possible to prevent the positional deviation of the landing point Z where each droplet landed on the recording medium. In the present invention, for the nozzles N _{1 to} N _m and N _{n−m + 1 to} N _n located in one and the other end regions EA1 and EA2 which are part of the nozzle row 2, the time difference Δt is set to the discharge timing. Therefore, the amount of data for correcting the ejection timing can be reduced. Therefore, the storage area for correction data is reduced. Further, since the amount of data is small, it is possible to input data reliably in a short time.

Further, with the center in the reference direction K of the nozzle row 2 as the center point Cp, the nozzle N located in one end area EA1 and the nozzle N located in the other end area EA2 are positioned at symmetrical points with respect to the center point Cp. In this case, the time difference Δt between the two drive signals Ds corresponding to each of the two nozzles N located at the symmetry point is equal to each other. Specifically, the nozzle N _m in one end area EA1 and the nozzle N _{n-m + 1 in the} other end area EA2 are positioned symmetrically about the center point Cp, and the nozzle N _m-1 and the nozzle N N _{n−m + 2} ,..., The nozzle N ₂ and the nozzle N _n−1 , and the nozzle N ₁ and the nozzle N _n are positioned symmetrically around the center point Cp. Then, a time difference Delta] t _m of the drive signal Ds _m corresponding to the nozzle N _m, the drive signal Ds _{n-m + 1} of the time difference Δt _{n-m + 1} are equal corresponding to the nozzle N _{n-m + 1.} Similarly, Δt _m−1 = Δt _{n−m + 2} , Δt _m−2 = Δt _{n−m + 3} ,..., Δt ₂ = Δt _n−1 and Δt ₁ = Δt _n are set. As a result, for the nozzles N located in one and the other end areas EA1 and EA2 of the nozzle row 2, the nozzles located in the one and the other end areas EA1 and EA2 without increasing the data amount for correcting the ejection timing. The ejection timing of droplets ejected from N can be corrected.

Further, when the position of the nozzle N located in one end area EA1 is represented by a coordinate x that increases from the center of the nozzle row 2 toward one end, the drive corresponding to the nozzle N located at the point of the coordinate x. The time difference Δt of the signal Ds can be expressed by a linear function of the coordinate x. For example, the position of the nozzle N _m is x = 1, the position of the nozzle N _m−1 is x = 2,..., The position of the nozzle N ₂ is x = m−1, and the position of the nozzle N ₁ is x = m. In this case, the time difference Δt of the drive signal Ds corresponding to the nozzle N (x) at the point x can be expressed by Expression (1). C ₁ is a linear coefficient (constant) of a linear function.
Δt (x) = C ₁ x (1)
The position of the nozzle N located in the other end area EA2 can be similarly expressed. As a result, the 2m time difference Δt set in the 2m drive signals Ds corresponding to the 2m nozzles N located in the one and the other end areas EA1 and EA2 is set to be equal to that of the nozzle N located in the end area EA. All can be calculated by the number m and the primary coefficient C ₁ . Therefore, compared to the conventional method, the number of input data for setting the time difference Δt can be greatly reduced, the setting data storage area can be reduced, and input errors can be prevented.

  In the liquid jet head 1 according to the first embodiment, an example in which the time difference Δt is provided in the nozzles N located in both the one end area EA1 and the other end area EA2 with the central area CA interposed therebetween is shown. Alternatively, a time difference Δt may be provided only in one end area EA1 or the other end area EA2.

  In the first embodiment, the ejection timing for ejecting droplets from the nozzle N in the end area EA is later than the ejection timing for ejecting droplets from the nozzle N in the central area CA, and the time difference Δt is set to the nozzle. It is set so as to increase from the center to the end of row 2. However, depending on the structure of the actuator unit 3 and the nozzle row 2 and the driving conditions, the nozzle N located in the central area CA of the nozzle row 2 has a higher droplet discharge speed than the nozzle N located in the end area EA. In addition, among the nozzles N in the end area EA, the speed difference may increase as the nozzle N is closer to the end of the nozzle row 2. In this case, the discharge timing for discharging droplets from the nozzles N in the end area EA is earlier than the discharge timing for discharging droplets from the nozzles N in the central area CA, and the time difference Δt is equal to the end of the nozzle row 2. Set to increase toward. Others are the same as the configuration of the first embodiment. Also in this case, compared with the conventional method, the number of input data for setting the time difference Δt is greatly reduced, the setting data storage area is reduced, and input errors can be prevented.

  In FIG. 1, the drive signal Ds for driving each nozzle N is represented by a single pulse Ps. However, the drive signal Ds may be composed of a plurality of pulses, or may record a gradation expression. Good. When a plurality of pulses are included, the time difference Δt may be set with reference to the pulse to be given last, or the time difference Δt may be set with reference to the pulse to be given first. In FIG. 1, the time difference Δt of the drive signal Ds in the end area EA is set between the start end of the single pulse Ps of the drive signal Ds in the center area CA and the start end of the single pulse Ps of the drive signal Ds in the end area EA. However, instead of this, a time difference between the end of the single pulse Ps of the drive signal Ds in the central area CA and the end of the single pulse Ps of the drive signal Ds in the end area EA may be used. In any case, the actual discharge timing at which the droplet is discharged may be used. In the first embodiment, a time difference Δt is provided in the ejection timing for ejecting droplets for the nozzles N located in one and the other end regions EA1 and EA2 of the nozzle row 2, but one or the other end region EA1. , A time difference Δt may be provided at the ejection timing at which droplets are ejected only to EA2.

(Second embodiment)
FIG. 3 is a configuration diagram of the liquid jet head 1 according to the second embodiment of the present invention. The difference from the first embodiment is that the liquid ejecting head 1 includes a drive unit 4 that generates a drive signal Ds, and other configurations are the same as those of the first embodiment. Therefore, the drive unit 4 will be mainly described below. The same portions or portions having the same function are denoted by the same reference numerals.

  The liquid ejecting head 1 includes a driving unit 4 that generates a driving signal Ds, an actuator unit 3 that inputs the driving signal Ds and discharges droplets from the corresponding nozzle N, and a nozzle in which a plurality of nozzles N are arranged in a reference direction K. Row 2. The drive unit 4 receives the set value Sd and generates the time difference information Jh, the waveform generation unit 6 that acquires the time difference information Jh and the image data Id and generates the drive waveform Dw, and the drive waveform Dw. And a signal generation unit 7 for generating a drive signal Ds for driving the actuator unit 3. This will be specifically described below.

The setting value Sd acquired by the calculation unit 5 is, for example, a selection value for whether or not to adjust the discharge timing, the number m of nozzles N located in one or the other end area EA1, WA2, and the position of the nozzle N It is a primary coefficient C ₁ or the like that represents the amount of change in the time difference Δt. As already described in the first embodiment, the primary coefficient C ₁ is the drive corresponding to the nozzle N (x) at the point x when the position of the nozzle N located in the end area EA is represented by the coordinate x. A time difference Δt (x) of the signal Ds (x) is expressed by Expression (1).

The calculation unit 5 includes one end area EA1 including nozzles N _{1 to} N _m having different discharge timings and nozzles N _{m + 1 to} N _nm having the same discharge timing based on the acquired set value Sd. And the other end area EA2 including the nozzles N _{n−m + 1 to} N _n having different discharge timings. The calculation unit 5 includes time differences Δt _{1 to} Δt _m and Δt _n-m corresponding to the nozzles N _{1 to} N _m and N _{n-m + 1 to} N _n located in the one and other end regions EA1 and EA2. _{+1 to} Δt _n are set. At this time, Δt ₁ > Δt ₂ >...> Δt _m and time difference information Jh having a relationship of Δt _n > Δt _n-1 >...> Δt _{n-m + 2} > Δt _{n-m + 1.} Is generated. Furthermore, the calculation unit 5 can calculate each time difference Δt with respect to each of the nozzles N by using a primary coefficient C _1. Specifically, the coordinate from the central region CA of the nozzle row 2 toward one end is set as x, and the time difference Δt (x) of the drive signal Ds corresponding to the nozzle N (x) is calculated by the equation (1). Can do. The time difference information Jh can be generated by calculating the other end area EA2 in the same manner.

The waveform generation unit 6 generates a drive waveform Dw for discharging droplets from each nozzle N from the image data Id and the time difference information Jh. Specifically, latches n image data Id to be driven temporarily latching means or the like, the n generates a drive waveform Dw ₁ ~Dw _n including a discharge pulse in accordance with the image data Id. When the drive waveform Dw is generated, the drive waveform Dw is associated with each of the nozzles N _{1 to} N _m and N _{n−m + 1 to} N _n located in one and the other end regions EA1 and EA2 based on the time difference information Jh. To set a delay time of the time difference Δt. More specifically, a time difference Δt ₁ is set for the drive waveform Dw ₁ of _one end area EA1, a time difference Δt ₂ is set for the drive waveform Dw _2, and a delay time of the time difference Δt _m is set for the drive waveform Dw _m. To do. No delay time is set for the drive waveforms Dw _{m + 1 to} Dw _nm in the central area CA. Drive waveform Dw _{n-m +} time difference Δt _{n-m + 1} to ₁ of the other end region EA2, the drive waveform Dw _{n-m + 2} to the time difference Δt _{n-m + 2} ··· driving waveform Dw _n Sets each delay time of the time difference Δt _n . Here, there is a relationship of Δt ₁ > Δt ₂ >...> Δt _{m and} a relationship of Δt _n > Δt _n-1 >...> Δt _{n-m + 2} > Δt _{n-m + 1.} . Signal generator 7 outputs a drive signal Ds ₁ to DS _n generated by boosting the driving waveform Dw ₁ ~Dw _n input to a predetermined voltage to each actuator A ₁ to A _n of the actuator unit 3. Each actuator A ₁ to A _n can eject droplets from the nozzles N ₁ to N _n corresponding in response to a drive signal Ds ₁ ~Ds _n.

  As described above, the nozzle N in the central area CA of the nozzle row 2 has a constant droplet discharge speed, and the nozzle N in the end area EA has a changed droplet discharge speed, so that the nozzle N near the end of the nozzle row 2 is changed. For the liquid jet head 1 in which the amount of change in the discharge speed increases, a time difference Δt is provided in the discharge timing of the drive signal Ds corresponding to the nozzle N located in the end area EA, and the nozzle N close to the end of the nozzle row 2 As the time difference Δt increases. Thereby, it is possible to land the droplet on the recording medium with high accuracy. The arithmetic unit 5 and the waveform generation unit 6 can be configured by using physically separated circuits, but physically using an LSI such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). It may be configured without being aware of the target boundary.

(Third embodiment)
FIG. 4 is a flowchart showing a signal processing method according to the third embodiment of the present invention. The third embodiment is a signal processing method for driving the liquid jet head 1 of the second embodiment. Hereinafter, a description will be given with reference to FIGS. 4 and 3.

  As shown in FIG. 3, the liquid ejecting head 1 includes a driving unit 4 that generates a driving signal Ds, an actuator unit 3 that inputs the driving signal Ds and discharges droplets from the corresponding nozzle N, and a plurality of nozzles N. And a nozzle row 2 arranged in the reference direction K. The drive unit 4 receives the set value Sd and generates the time difference information Jh, the waveform generation unit 6 that acquires the time difference information Jh and the image data Id and generates the drive waveform Dw, and the drive waveform Dw. And a signal generation unit 7 that generates a drive signal Ds for driving the actuator unit 3.

As shown in FIG. 4, first, in the set value specifying step S1, the calculation unit 5 specifies the set value Sd. The set value Sd is, for example, a selection value for selecting whether or not to adjust the discharge timing, the number m of nozzles N included in one or the other end region EA1, EA2, the time difference Δt with respect to the position of the nozzle N, or The amount of change of the time difference Δt with respect to the position of the nozzle N (for example, the linear coefficient C ₁ when changing linearly) or the like. The set value Sd may be supplied from the outside, or may be stored in a predetermined area in advance. Next, in the end region specifying step S2, the calculation unit 5 specifies the end region EA of the nozzle row 2 in which the plurality of nozzles N are arranged in the reference direction K based on the set value Sd. For example, including the nozzles N ₁ ~ nozzles N _m of one side of the nozzle array 2 at one end region EA1, inclusion of nozzles N _{n-m + 1} ~ nozzles N _n in the other end region EA2. The nozzles N included in the end area EA have different droplet discharge timings.

Next, in the time difference calculation step S3, the calculation unit 5 calculates a time difference Δt that determines the discharge timing of the liquid droplets discharged from the nozzle N according to the position of the nozzle N located in the end region EA. The calculation unit 5 calculates each time difference Δt set to the drive signal Ds corresponding to each nozzle N with reference to the set value Sd. For example, assuming that the coordinate increasing from the center to the end of the nozzle row 2 is x, the time difference Δt (x) of the drive signal Ds corresponding to the nozzle N (x) is calculated by the above equation (1), and each nozzle N ₁ Time difference information Jh associated with each of ˜N _m and N _{n−m + 1 to} N _n is generated.

Next, in drive signal generation step S4, the waveform generator 6 generates a drive waveform Dw in which the time difference Δt is set based on the time difference information Jh. The signal generator 7 generates a drive signal Ds based on the drive waveform Dw. Specifically, the waveform generator 6 sets a time difference Δt for the drive waveform Dw corresponding to the nozzle N in the end area EA, and sets a time difference Δt for the drive waveform Dw corresponding to the nozzle N in the center area CA. do not do. For example, the driving waveform Dw time difference Delta] t ₁ to ₁ of one of the end regions EA1, the drive waveform Dw ₂ is a time difference Delta] t ₂ · · · driving waveform Dw _m to set the delay time of the time difference Delta] t _m. No delay time is set for the drive waveforms Dw _{m + 1 to} Dw _nm in the central area CA. Drive waveform Dw _{n-m +} time difference Δt _{n-m + 1} to ₁ of the other end region EA2, the drive waveform Dw _{n-m + 2} to the time difference Δt _{n-m + 2} ··· driving waveform Dw _n Sets each delay time of the time difference Δt _n . Here, there is a relationship of Δt ₁ > Δt ₂ >...> Δt _{m and} a relationship of Δt _n > Δt _n-1 >...> Δt _{n-m + 2} > Δt _{n-m + 1.} . Signal generation unit 7 is raised to the driving waveform Dw ₁ ~Dw _n input to a predetermined voltage to generate a driving signal Ds ₁ ~Ds _n.

  Next, in drive signal supply step S <b> 5, the signal generation unit 7 supplies the drive signal Ds to the actuator unit 3. Next, in determination step S6, the drive unit 4 determines whether or not to interrupt the recording. If the recording is not interrupted (No), the driving unit 4 repeats from the drive signal generation step S4. At this time, the waveform generation unit 6 latches the image data Id for the next one period in the latch means, and generates the drive waveform Dw in which the time difference Δt is set based on the time difference information Jh. The signal generator 7 boosts the drive waveform Dw to a predetermined voltage and generates a drive signal Ds.

  In this way, since a time difference is provided in the discharge timing for the nozzles located in the end region that is a part of the nozzle row, the amount of data for correcting the discharge timing can be reduced. Therefore, the storage area for correction data is reduced. Further, since the amount of data is small, it is possible to input data reliably in a short time.

(Fourth embodiment)
FIG. 5 is a configuration diagram of the liquid jet head 1 according to the fourth embodiment of the present invention. The difference from the first embodiment is that the time difference Δt that determines the discharge timing of the drive signal Ds for discharging the droplets from the nozzle N located in the end region EA is different, and the other configurations are the same as in the first embodiment. It is. Accordingly, the following mainly describes differences from the first embodiment. The same portions or portions having the same function are denoted by the same reference numerals.

As shown in FIG. 5, when the position of the nozzle N located in one end area EA1 is represented by the coordinate x that increases from the center of the nozzle row 2 toward the end, the nozzle N located at the point of the coordinate x The corresponding time difference Δt of the drive signal Ds is represented by a quadratic function of the coordinate x. For example, the position of the nozzle N _m is x = 1, the position of the nozzle N _m−1 is x = 2,..., The position of the nozzle N ₂ is x = m−1, and the position of the nozzle N ₁ is x = m. Then, the time difference Δt (x) of the drive signal Ds corresponding to the nozzle N (x) at the point x is expressed by the equation (2). Here, C ₂ is a quadratic coefficient (constant) of a quadratic function.
Δt (x) = C ₂ x ² (2)
The time difference Δt located in the other end area EA2 can be similarly expressed. That is, the position of the nozzle N _{n-m + 1} is y = 1, the position of the nozzle N _{n-m + 2} is y = 2,..., The position of the nozzle N _n-1 is y = n−1, and the nozzle N _If the position of _n is y = n, the time difference Δt (y) of the drive signal Ds corresponding to the nozzle N (y) at the point y is expressed by Expression (2) in which x is replaced with y.

In the liquid jet head 1 according to the present embodiment, the nozzle N located in one and the other end regions EA1 and EA2 of the nozzle row 2 has a faster ejection speed than the nozzle N located in the central region CA of the nozzle row 2. . In particular, the discharge speed of the nozzles N located in the one and other end areas EA1 and EA2 increases in proportion to the square of the distance from the nozzle N at the end of the central area CA. The variation in the discharge speed can be corrected by setting the number m of nozzle N located one or the other end region EA1, EA2, the time difference Δt determined by secondary factors C ₂ to the drive signal Ds. Therefore, compared with the conventional method, the number of input data for setting the time difference Δt is greatly reduced, the setting data storage area is reduced, and setting data input errors can be prevented.

  Since other configurations and operations are the same as those in the first embodiment, description thereof is omitted. As in the first embodiment, the center of the nozzle row 2 in the reference direction K is the center point Cp, and the nozzle N located in one end area EA1 and the nozzle N located in the other end area EA2 are When located at a symmetric point with respect to the center point Cp, the time differences Δt between the two drive signals Ds corresponding to the two nozzles N located at the symmetric point are equal. In addition, depending on the structure of the actuator unit 3 and the nozzle row 2 and the driving conditions, the nozzle N in the central area CA of the nozzle row 2 may have a higher droplet discharge speed than the nozzle N in the end area EA. . In this case, the discharge timing for discharging droplets from the nozzle N in the end area EA is earlier than the discharge timing for discharging droplets from the nozzle N in the central area CA, and the time difference Δt is set to the end of the nozzle row 2. Set to increase toward the front. For example, it may be configured such that the discharge timing is advanced in proportion to the square of the distance from the nozzle N at the end of the central area CA of the nozzle N in the end area EA. In the present embodiment, the time difference Δt is expressed by Expression (2), but instead, it may be expressed by another function such as a cubic function according to the characteristics of the head unit 11. Further, it is possible to use a cubic or higher order function as necessary.

  In FIG. 5, the drive signal Ds for driving each nozzle N is represented by a single pulse Ps. However, it may be constituted by a plurality of pulses, or a gradation expression may be recorded. When a plurality of pulses are included, the time difference Δt can be set based on the last pulse or the first pulse. The time difference Δt of the drive signal Ds in the end area EA is the time difference between the start end of the single pulse Ps of the drive signal Ds in the center area CA and the start end of the drive signal Ds in the end area EA. Instead, it may be the time between the end of the single pulse Ps of the drive signal Ds in the central area CA and the end of the single pulse Ps of the drive signal Ds in the end area EA. In any case, the difference may be a difference in ejection timing at which droplets are actually ejected.

In addition, it cannot be overemphasized that the drive signal Ds in this embodiment can be applied as it is to the liquid jet head 1 and the signal processing method of the second or third embodiment. In this case, for the set value Sd, the time difference Δt is calculated according to the equation (1) using the primary coefficient C ₁ , the time difference Δt is calculated according to the equation (2) using the secondary coefficient C ₂ , or more than the third order. It is possible to add a mode selection capable of selecting, for example, calculating the time difference Δt according to a multi-order function.

(Fifth embodiment)
FIG. 6 is a configuration diagram of the liquid jet head 1 according to the fifth embodiment of the present invention. The same portions or portions having the same function are denoted by the same reference numerals.

As shown in FIG. 6, the liquid ejecting head 1 includes a nozzle row 2 in which a plurality of nozzles N are arranged in the reference direction K, and an actuator unit that inputs a drive signal Ds corresponding to the nozzles N and discharges droplets from the nozzles N. 3. The nozzles N in the nozzle row 2 are arranged linearly at equal intervals. In the drive signal Ds for driving each nozzle N, the nozzles N _{1 to} N _p (p is an integer smaller than n) that discharge droplets in one cycle constitute a continuous region R that is continuous in the reference direction K. The drive signal Dsc corresponding to the nozzle Nc located in the center of the region R or in the vicinity thereof and the drive signal Ds corresponding to the nozzle N located in the end region EA of the continuous region R have a time difference Δt in the droplet discharge timing. Have Further, among the nozzles N located in the end area EA, the drive corresponding to the nozzle N near the end of the continuous area R from the time difference Δt of the drive signal Ds corresponding to the nozzle N near the center of the continuous area R or the vicinity thereof. The time difference Δt of the signal Ds is large. That is, among the nozzles N located in the end area EA, the nozzle N closer to the end of the continuous area R has a larger time difference Δt of the corresponding drive signal Ds.

  Here, the nozzle row 2 and the actuator unit 3 constitute a head unit 11. The head unit 11 further includes a pressure chamber 9 and a liquid chamber 10 for supplying a liquid to each pressure chamber 9. The actuator unit 3 includes a piezoelectric body (not shown) that deforms the side surface of each pressure chamber 9 and an electrode (not shown) that deforms the piezoelectric body by applying an electric field. Each actuator A corresponding to each nozzle N is configured integrally.

This will be specifically described. One cycle of image data Id for discharging droplets is continuous in the continuous region R. This continuous region R corresponds to the nozzles N _{1 to} N _p . The drive signal Dsc corresponding to the nozzle Nc located in the center of the continuous region R or in the vicinity thereof and the nozzles N _{1 to} N _q (q is an integer smaller than p) located in one end region EA1 are droplets. There is a time difference Δt in the discharge timing. Similarly, the drive signal Dsc corresponding to the nozzle Nc and the nozzles N _{p−q + 1 to} N _p located in the other end area EA2 have a time difference Δt in the droplet discharge timing. Among the nozzles N _{1 to} N _q located in one end area EA1, the nozzle N closer to one end of the continuous area R has a larger time difference Δt of the corresponding drive signal Ds. That is, Δt _q <Δt _q−1 ... <Δt ₂ <Δt ₁ . Similarly, among the nozzles N _{p−q + 1 to} N _p located in the other end area EA2, the time difference Δt of the corresponding drive signal Ds is larger as the nozzle N is closer to the other end of the continuous area R. In other words, it has become a _{Δt p-q + 1 <Δt} p-q + 2 ··· <Δt p-1 <Δt p.

In FIG. 6, a central area CA is set between one end area EA1 and the other end area EA2, and the drive signals Ds corresponding to the nozzles N _{q + 1 to} N _pq located in the central area CA are set. Does not set the time difference Δt. When the number of nozzles N located in the continuous region R is small, the central region CA is not set, and the time difference Δt is not set for the drive signal Ds corresponding to the nozzle Nc located in the center of the continuous region R or in the vicinity thereof. The drive signal Dsc corresponding to the nozzle Nc located at or near the center may be used as a reference for the time difference Δt.

Here, in the liquid jet head 1 of the fifth embodiment, one and the other end regions EA1, EA2 of the continuous region R are applied to the liquid droplets ejected from the nozzle Nc located in the center of the continuous region R or in the vicinity thereof. The liquid droplets ejected from the nozzle N located at the position have a speed difference. Of the nozzles N located in the end regions EA1 and EA2, the nozzle N near the end of the continuous region R is ejected from the speed difference of the droplets ejected from the nozzle N near the center of the continuous region R or the vicinity thereof. The above-mentioned speed difference of the droplets is large. That is, among the nozzles N located in the end regions EA1 and EA2, the nozzle N closer to one or the other end of the continuous region R has a larger difference in the speed of the ejected droplets. Therefore, the drive signal Ds ₁ to DS _q corresponding to the nozzle N ₁ to N _q located at one end region EA1, and the nozzle N _p-q + 1 ~N _p located on the other end region EA2 the corresponding drive signal Ds _{p-q + 1} ~Ds p providing a delay time of the time difference Delta] t. Then, the delay time of the time difference Δt is set larger for the nozzle N closer to the end of the continuous region R. This delay time is set for each cycle in which the image data Id is rewritten.

Accordingly, when the liquid ejecting head 1 and the recording medium move relative to each other and the liquid droplets are ejected from the nozzles N _{1 to} N _p , the positional deviation of the positions where the respective liquid droplets land on the recording medium is prevented. Can do. In the present invention, since the time difference Δt is set according to the pattern of the image data Id for each period of ejecting droplets, the recording quality can be improved. Further, since the time difference Δt is set only for the drive signal Ds corresponding to the nozzle N located in the end area EA, the amount of data for correcting the ejection timing can be reduced. Therefore, the storage area for correction data is reduced. Further, since the amount of data is small, it is possible to input data reliably in a short time.

Furthermore, with the center in the reference direction K of the continuous region R as the center point Cp, the nozzle N located in one end region EA1 and the nozzle N located in the other end region EA2 are positioned at symmetrical points with respect to the center point Cp. In this case, the two nozzles N positioned at the symmetrical point have the same time difference Δt between the drive signals Ds for discharging the droplets. Specifically, located symmetrically point around the center point Cp to the nozzle N _{p-q + 1} nozzle N _q and the other end region EA2 of one end region EA1, the nozzle N _q-1 The nozzles N _{p-q + 2} ,..., The nozzle N ₂ and the nozzle N _p−1 , and the nozzle N ₁ and the nozzle N _p are located at symmetrical points with the center point Cp as the center. Then, a time difference Delta] t _q of the drive signal Ds _q corresponding to the nozzle N _q, the nozzle N _{p-q +} time difference between the drive signal Ds _{p-q + 1} corresponding to ₁ Δt _{p-q + 1} are equal. Similarly, Δt _q−1 = Δt _{p−q + 2} , Δt _q−2 = Δt _{p−q + 3} ,..., Δt ₂ = Δt _p−1 and Δt ₁ = Δt _p are set. As a result, the nozzles N located in one and the other end regions EA1 and EA2 of the continuous region R are located in the one and the other end regions EA1 and EA2 without increasing the data amount for correcting the discharge timing. The ejection timing of droplets ejected from the nozzle N can be corrected.

Further, when the position of the nozzle N located in one end area EA1 is represented by the coordinate x increasing from the center of the continuous area R toward the end, the drive signal Ds corresponding to the nozzle N located at the point of the coordinate x. Can be expressed by a linear function or a quadratic function of the coordinate x. That is, using the equation (1) described in the first embodiment, the time difference Δt (x) of the drive signal Ds corresponding to the nozzle N (x) located at the coordinate x can be expressed as a linear function of the coordinate x. . Further, the time difference Δt (x) of the drive signal Ds corresponding to the nozzle N (x) located at the coordinate x can be expressed as a quadratic function of the coordinate x using the equation (2) described in the fourth embodiment. it can. Note that the time difference Δt is a time difference Δt ₁ set in advance in association with each nozzle N _{1 to} N _q , N _{pq to} N _p , instead of using a linear function or a quadratic function of the coordinates of each nozzle N. ~Δt _q, it may be used Δt _pq ~Δt _p.

In the liquid ejecting head 1 in this case, the nozzle N positioned in one and the other end regions EA1 and EA2 of the continuous region R has a higher droplet discharge speed than the nozzle Nc positioned in the center of the continuous region R. . In particular, the discharge speed of the nozzles N located in the one and other end areas EA1 and EA2 increases as the distance from the nozzle N at the end of the center point Cp or the center area CA increases. This variation in the discharge speed is corrected by setting the driving signal Ds to a time difference Δt determined by the number q of the nozzles N located in one or the other end area EA1, EA2, the primary coefficient C ₁ or the secondary coefficient C _2. can do. Therefore, compared with the conventional method, the number of input data for setting the time difference Δt is greatly reduced, the setting data storage area is reduced, and setting data input errors can be prevented.

  In addition, depending on the structure of the actuator unit 3 and the nozzle row 2 and the driving conditions, the nozzle N positioned in the center of the continuous region R may have a higher droplet discharge speed than the nozzle N in the end region EA. . In this case, the discharge timing for discharging droplets from the nozzle N in the end area EA is faster than the discharge timing for discharging droplets from the nozzle Nc located in the center, and the time difference Δt is set to the end of the continuous region R. Set to increase toward the front. For example, it may be configured such that the discharge timing is advanced in proportion to the square of the distance from the nozzle Nc located at the center of the continuous region R or in the vicinity thereof.

(Sixth embodiment)
FIG. 7 is a configuration diagram of the liquid jet head 1 according to the sixth embodiment of the present invention. The difference from the fifth embodiment is that the liquid jet head 1 includes a drive unit 4 that generates a drive signal Ds, and the other configurations are the same as those of the fifth embodiment. Therefore, the drive unit 4 will be mainly described below. The same portions or portions having the same function are denoted by the same reference numerals.

As shown in FIG. 7, the liquid ejecting head 1 includes a drive unit 4 that acquires image data Id and generates a drive signal Ds, and an actuator unit 3 that inputs the drive signal Ds and discharges droplets from the corresponding nozzle N. And a nozzle row 2 in which a plurality of nozzles N are arranged in the reference direction K. The drive unit 4 acquires the image data Id of one cycle, detects the continuous region R, and generates the region information Jr, and acquires the region information Jr and the set value Sd to generate the time difference information Jh. The calculation unit 5, the waveform generation unit 6 that acquires the time difference information Jh and the image data Id and generates the drive waveform Dw, and the signal generation unit 7 that generates the drive signal Ds that inputs the drive waveform Dw and drives the actuator unit 3. With. In FIG. 7, the drive waveform Dw constituting the continuous region R is Dw ₁ to Dw _p , the drive signal Ds is Ds ₁ to Ds _p , the actuator A is A _{1 to} A _p , and the nozzle N is N ₁ to N ₁ . Indicated as N _p . This will be specifically described below.

The continuous area detection unit 8 detects a continuous area R (see FIG. 6) in which the nozzles N that discharge liquid droplets are continuous in the reference direction K from one cycle of image data Id acquired from the outside. The area information Jr including the number p of the nozzles N included in R and the position of the nozzles N is generated. The calculation unit 5 acquires the region information Jr and the set value Sd, calculates the time difference Δt corresponding to each nozzle N, and generates the time difference information Jh. The set value Sd to be acquired is, for example, a selection value as to whether or not to adjust the discharge timing, the number q of the nozzles N located in one or the other end area EA1, EA2, the time difference Δt with respect to the position of the nozzle N, for example, The primary coefficient C ₁ and the secondary coefficient C ₂ represent the amount of change in the time difference Δt with respect to the position of the nozzle N.

The calculation unit 5 includes time differences Δt _{1 to} Δt _q and Δt _p-q corresponding to the nozzles N _{1 to} N _q and N _{p-q + 1 to} N _p located in one and the other end regions EA1 and EA2. to set the _{+1 ~Δt p.} At this time, Δt ₁ > Δt ₂ >...> Δt _q , and Δt _p > Δt _p-1 >...> Δt _{p-q + 2} > Δt _{p-q + 1.} Is generated. Further, the calculation unit 5 calculates each time difference Δt for each nozzle N using the above-described equations (1) and (2) using the primary coefficient C ₁ and the secondary coefficient C ₂ , and the time difference information Jh is obtained. Can be generated.

The waveform generation unit 6 generates a drive waveform Dw for discharging droplets from each nozzle N from the image data Id and the time difference information Jh. Specifically, image data Id to be driven at a time is stored in a storage unit such as a latch unit, and each drive waveform Dw is generated according to each image data Id. When generating the drive waveform Dw, based on the time difference information Jh, the nozzles N _{1 to} N _q and N _{p-q + 1 to} N _p located in one and the other end regions EA1 and EA2 of the continuous region R are displayed. A time difference Δt is set in association with each of the above. More specifically, the drive waveform Dw ₁ of _one end area EA1 has a time difference of time difference Δt ₁ , the drive waveform Dw ₂ has a time difference Δt _{2, and the} drive waveform Dw _q has a delay time of the time difference Δt _q. The delay time is not set to the drive waveforms Dw _{q + 1 to} Dw _pq of the central area CA of the continuous area R, and the nozzles N _{p-q + 1 to} N _p of the other end area EA2 are respectively set. to set the delay time of the time difference _{Δt p-q + 1 ~Δt p} . Here, there is a relationship of Δt ₁ > Δt ₂ >...> Δt _{q and} a relationship of Δt _p > Δt _p-1 >...> Δt _{p-q + 2} > Δt _{p-q + 1.} . The signal generator 7 outputs drive signals Ds _{1 to} Ds _p obtained by boosting the input drive waveforms Dw _{1 to} Dw _p to a predetermined voltage to the actuators A _{1 to} A _p of the actuator unit 3. The actuators A _{1 to} A _p discharge droplets from the corresponding nozzles N _{1 to} N _p according to the drive signals Ds _{1 to} Ds _p .

  The waveform generator 6 does not set the time difference Δt for the drive waveform Dw corresponding to the nozzle N that is not located in the end area EA. A plurality of continuous regions R may exist in one cycle of image data Id. The continuous region R is set when a predetermined number or more of the corresponding nozzles N exist according to the set value Sd. Similarly, one or the other end area EA1, EA2 is set when there are a predetermined number or more of corresponding nozzles N according to the set value. Further, depending on the structure of the actuator unit 3 and the nozzle row 2 and the driving conditions, the nozzle N located at the center of the continuous region R or in the vicinity thereof has a higher droplet discharge speed than the nozzle N in the end region EA. There is a case. In this case, the ejection timing for ejecting droplets from the nozzles N in the end area EA is a time difference Δt earlier than the ejection timing for ejecting droplets from the nozzles Nc located at or near the center of the continuous region R, and the time difference Δt. May be set so as to increase toward the end of the continuous region R.

  Thereby, every time the continuous region R is formed, the discharge timing of the droplets discharged from the nozzles N located in the end region EA is adjusted, so that the recording quality is prevented from changing according to the pattern of the image data Id. be able to. In addition, since the time difference Δt only needs to be set for the drive signal Ds corresponding to the nozzle N located in the end area EA, the amount of data for ejection timing correction can be reduced. Since the amount of data for correction is small, input can be performed reliably in a short time.

(Seventh embodiment)
FIG. 8 is a flowchart showing a signal processing method according to the seventh embodiment of the present invention. The seventh embodiment is a signal processing method for driving the liquid jet head 1 of the sixth embodiment. Hereinafter, a description will be given with reference to FIGS. The same portions or portions having the same function are denoted by the same reference numerals.

  As shown in FIG. 7, the liquid ejecting head 1 includes a driving unit 4 that generates a driving signal Ds, an actuator unit 3 that inputs the driving signal Ds and discharges droplets from the corresponding nozzle N, and a plurality of nozzles N. And a nozzle row 2 arranged in the reference direction K. The drive unit 4 acquires the image data Id of one cycle, detects the continuous region R and generates the region information Jr, and acquires the region information Jr and the set value Sd to generate the time difference information Jh. A calculation unit 5 that obtains time difference information Jh and image data Id and generates a drive waveform Dw, and a signal generation unit that receives the drive waveform Dw and generates a drive signal Ds that drives the actuator unit 3 7.

As shown in FIG. 8, first, in the set value specifying step S1, the calculation unit 5 specifies the set value Sd. The set value Sd is, for example, a selection value for selecting whether or not to adjust the discharge timing, the minimum number pmin of the nozzles N included in the continuous area R, the number q of the nozzles N included in the end area EA, and the nozzle N Is a first order coefficient C ₁ , a second order coefficient C ₂ , a third order or higher coefficient, etc. In the image data acquisition step S7, the continuous area detection unit 8 acquires image data Id. Further, in the continuous region specifying step S8, the continuous region detecting unit 8 detects the continuous region R in which the nozzles N that eject droplets are continuous from the acquired image data Id of one cycle, and the nozzle N corresponding to the continuous region R is detected. The area information Jr consisting of the position and number of 6 and 7, the nozzles N _{1 to} N _p correspond to the continuous region R.

In the end region specifying step S2, the calculation unit 5 acquires the region information Jr and the set value Sd, and specifies the end region EA in the continuous region R based on the set value Sd. Specifically, the arithmetic unit 5 adjusts the discharge timing when the number p of the nozzles N included in the continuous region R exceeds the minimum number pmin of the nozzles N determined at the set value Sd. The computing unit 5 identifies the end area EA in the continuous area R based on the set value Sd. In FIG. 6, one end area EA1 is set in one of the continuous areas R, and the other end area EA2 is set in the other. One end region EA1 is a nozzle N ₁ to N _q, the other end region EA2 includes a nozzle _{N p-q + 1 ~N p} .

Next, in the time difference calculation step S3, the calculation unit 5 calculates a time difference Δt that determines the discharge timing of the liquid droplets discharged from the nozzle N according to the position of the nozzle N located in the end region EA. The calculator 5 calculates a time difference Δt set for the drive signal Ds corresponding to each nozzle N located in the end area EA with reference to the set value Sd. For example, when a coordinate that increases from the center to the end of the continuous region R is represented by x, the time difference Δt (x) of the drive signal Ds with respect to the nozzle N (x) is calculated by the above formulas (1) and (2). The time difference information Jh associated with each of the nozzles N _{1 to} N _q and N _{p-q + 1 to} N _p is generated. The arithmetic unit 5, the formula (1), instead of calculating the equation (2), each nozzle with a pre-stored time difference _{Δt 1 ~Δt q, Δt p-} q + 1 ~Δt p N _{1 to} N _q and N _{p-q + 1 to} N _p may be associated with each other.

Next, in drive signal generation step S4, the waveform generation unit 6 generates a drive waveform Dw in which the time difference Δt is set based on the time difference information Jh, and the signal generation unit 7 generates the drive signal Ds based on the drive waveform Dw. Generate. Specifically, the waveform generator 6 sets a time difference Δt to the drive waveform Dw corresponding to each of the nozzles N _{1 to} N _q and N _{p-q + 1 to} N _p in the one and other end regions EA1 and EA2. The time difference Δt is not set in the drive waveform Dw corresponding to the nozzles N _{q + 1 to} N _pq located in the central area CA. For example, the driving waveform Dw time difference Delta] t ₁ to ₁ of one of the end regions EA1, the drive waveform Dw ₂ is a time difference Delta] t ₂ · · · driving waveform Dw _q sets the delay time of the time difference Delta] t _q. No delay time is set for the drive waveforms Dw _{q + 1 to} Dw _pq−1 in the central area CA. Setting the delay time of each nozzle N _{p-q + 1} ~N each time difference in _{p Δt p-q + 1 ~Δt} p at the other end region EA2. Here, there is a relationship of Δt ₁ > Δt ₂ >...> Δt _{q and} a relationship of Δt _p > Δt _p-1 >...> Δt _{p-q + 2} > Δt _{p-q + 1.} . The signal generator 7 boosts the input drive waveforms Dw and Dw _{1 to} Dw _p to a predetermined voltage to generate drive signals Ds and Ds _{1 to} Ds _p .

  The waveform generator 6 does not set the time difference Δt for the drive waveform Dw corresponding to the nozzle N that is not located in the end area EA. A plurality of continuous regions R may exist in one cycle of image data Id. Further, depending on the structure of the actuator unit 3 and the nozzle row 2 and the driving conditions, the nozzle Nc located in the center of the continuous region R or in the vicinity thereof, or the nozzle N located in the central region CA is the nozzle N in the end region EA. In some cases, the discharge speed of the droplets may be faster. In this case, the ejection timing for ejecting droplets from the nozzles N in the end area EA is a time difference Δt faster than the ejection timing for ejecting droplets from the nozzles Nc located at or near the center or the nozzles N located at the center region CA. In addition, the time difference Δt may be set so as to increase toward the end of the continuous region R.

  Next, in drive signal supply step S <b> 5, the signal generation unit 7 supplies the drive signal Ds to the actuator unit 3. Next, in determination step S6, the drive unit 4 determines whether or not to interrupt the recording. If the recording is not interrupted (No), the signal processing is continued from the image data acquisition step S7. That is, the continuous area detection unit 8 generates area information Jr for image data Id for the next one cycle, and executes subsequent signal processing.

  As described above, since the time difference Δt is set according to the pattern of the image data Id for each period of ejecting droplets, the recording quality is improved. Further, since the time difference Δt is set only for the drive signal Ds corresponding to the nozzle N located in the end area EA, the amount of data for correcting the ejection timing can be reduced. Since the amount of data for correction is small, input can be performed reliably in a short time.

(Eighth embodiment)
FIG. 9 is an exploded perspective view of the head portion 11 of the liquid jet head 1 according to the eighth embodiment of the present invention. It is an example of the head part 11 in 1st-7th embodiment. The same portions or portions having the same function are denoted by the same reference numerals.

  The head unit 11 includes a piezoelectric substrate 12 having an actuator A, a cover plate 17 having a liquid chamber 10, and a nozzle plate 19 having a nozzle N. The piezoelectric substrate 12 includes ejection grooves 14a and non-ejection grooves 14b arranged in the reference direction K of the upper surface US, and side walls 13 that partition the ejection grooves 14a and the non-ejection grooves 14b. The ejection grooves 14a and the non-ejection grooves 14b open to the front end surface SS of the piezoelectric substrate 12 and terminate at the rear of the upper surface US. The side wall 13 includes drive electrodes 15 on both sides of the ejection groove 14a side and the non-ejection groove 14b side. The piezoelectric substrate 12 further includes a common terminal 16a electrically connected to the drive electrode 15 on the ejection groove 14a side and an active terminal 16b electrically connected to the drive electrode 15 on the non-ejection groove 14b side behind the upper surface US. Is provided. The piezoelectric substrate 12 can be made of piezoelectric ceramics, such as PZT ceramics. Polarization processing is performed in advance in the direction perpendicular to the piezoelectric substrate 12 and the upper surface US.

  The cover plate 17 includes a liquid chamber 10 that communicates with the rear side of each ejection groove 14 a via a slit 18. The liquid chamber 10 does not communicate with the non-ejection groove 14b. The cover plate 17 is bonded to the upper surface US of the piezoelectric substrate 12. Thereby, the upper part of the discharge groove 14 a and the non-discharge groove 14 b is covered except for the slit 18, and the discharge groove 14 a constitutes the pressure chamber 9. The nozzle plate 19 includes a nozzle N communicating with each discharge groove 14 a and is bonded to the end surface SS of the piezoelectric substrate 12.

  The head unit 11 is driven as follows. When the liquid is supplied to the liquid chamber 10, the liquid flows into each discharge groove 14 a through the slit 18. When the drive signal Ds is given to the common terminal 16a and the active terminal 16b, the side wall 13 constituting the ejection groove 14a is deformed, the liquid filling the ejection groove 14a is pressurized, and the droplet is ejected from the nozzle N. Here, the side walls 13 on both sides of the ejection groove 14a and the drive electrodes 15 installed on both side surfaces function as the actuator A.

  In the case where the ejection grooves 14a arranged in parallel are located at the end portion of the arrangement in the reference direction K and the case where they are located away from the end portion, the arrangement of the piezoelectric substrate 12 and the liquid chamber 10 around the ejection groove 14a is different. Different. Therefore, it is considered that a discharge speed difference is generated between the discharge groove 14a near the end and the discharge groove 14a that is separated. In addition, whether or not the discharge groove 14a is close to the end of the array in the reference direction K, the discharge groove close to the end of the continuous region R when the continuous discharge region 14a is formed. It is considered that a discharge speed difference occurs due to the influence of crosstalk between 14a and the discharge groove 14a away from the end of the continuous region R. The present invention eliminates such structural effects and crosstalk effects by providing the drive signal Ds with a time difference Δt.

  The head unit 11 may be a side shoot type in addition to the edge shoot type as in the present embodiment. Further, it is possible to use a liquid circulation type head unit 11 that allows liquid to flow in from one end of the discharge groove 14a and flow out from the other end. Moreover, instead of using the thickness sliding deformation of the piezoelectric body as the pressure chamber 9 as in the present embodiment, another deformation mode may be used.

(Ninth embodiment)
FIG. 10 is a schematic perspective view of a liquid ejecting apparatus 30 according to the ninth embodiment of the present invention. The liquid ejecting apparatus 30 includes a moving mechanism 40 that reciprocates the liquid ejecting heads 1 and 1 ′, and a flow path unit that supplies the liquid to the liquid ejecting heads 1 and 1 ′ and discharges the liquid from the liquid ejecting heads 1 and 1 ′. 35, 35 ′, liquid pumps 33, 33 ′ and liquid tanks 34, 34 ′ communicating with the flow path portions 35, 35 ′. Each liquid ejecting head 1, 1 ′ is provided with an actuator unit 3 that receives a drive signal Ds in which a time difference Δt of ejection timing is set and ejects droplets from the nozzle N. As the liquid pumps 33 and 33 ′, either or both of a supply pump that supplies the liquid to the flow path portions 35 and 35 ′ and a discharge pump that discharges the liquid are installed, and the liquid is circulated. In addition, a pressure sensor and a flow rate sensor (not shown) may be installed to control the liquid flow rate. The liquid ejecting heads 1 and 1 ′ use the liquid ejecting head 1 that is driven by supplying the driving signal Ds described in the first to eighth embodiments to the actuator unit 3.

  The liquid ejecting apparatus 30 includes a pair of conveying units 41 and 42 that convey a recording medium 44 such as paper in the main scanning direction, liquid ejecting heads 1 and 1 ′ that eject liquid onto the recording medium 44, and a liquid ejecting head. 1, 1 ′ carriage unit 43, liquid tanks 34, 34 ′ and liquid pumps 33, 33 ′ that supply the liquid stored in the liquid tanks 34, 34 ′ to the flow path parts 35, 35 ′, And a moving mechanism 40 that scans 1 ′ in the sub-scanning direction orthogonal to the main scanning direction. A control unit (not shown) controls and drives the liquid ejecting heads 1, 1 ′, the moving mechanism 40, and the conveying units 41 and 42.

  The pair of conveying means 41 and 42 includes a grid roller and a pinch roller that extend in the sub-scanning direction and rotate while contacting the roller surface. A grid roller and a pinch roller are moved around the axis by a motor (not shown), and the recording medium 44 sandwiched between the rollers is conveyed in the main scanning direction. The moving mechanism 40 couples a pair of guide rails 36 and 37 extending in the sub-scanning direction, a carriage unit 43 slidable along the pair of guide rails 36 and 37, and the carriage unit 43 to move in the sub-scanning direction. An endless belt 38 is provided, and a motor 39 that rotates the endless belt 38 via a pulley (not shown) is provided.

  The carriage unit 43 mounts a plurality of liquid jet heads 1, 1 ′, and ejects, for example, four types of liquid droplets of yellow, magenta, cyan, and black. The liquid tanks 34 and 34 'store liquids of corresponding colors and supply them to the liquid jet heads 1 and 1' via the liquid pumps 33 and 33 'and the flow path portions 35 and 35'. Each liquid ejecting head 1, 1 ′ ejects droplets of each color according to the drive signal. An arbitrary pattern is recorded on the recording medium 44 by controlling the timing at which liquid is ejected from the liquid ejecting heads 1, 1 ′, the rotation of the motor 39 that drives the carriage unit 43, and the conveyance speed of the recording medium 44. I can.

  In this embodiment, the moving mechanism 40 moves the carriage unit 43 and the recording medium 44 to perform recording, but instead, the carriage unit is fixed and the moving mechanism is the recording medium. It may be a liquid ejecting apparatus that records the image by moving it two-dimensionally. That is, the moving mechanism may be any mechanism that relatively moves the liquid ejecting head and the recording medium.

DESCRIPTION OF SYMBOLS 1 Liquid jet head 2 Nozzle row | line | column 3 Actuator part 4 Drive part, 5 Calculation part, 6 Waveform generation part, 7 Signal generation part, 8 Continuous area | region detection part 9 Pressure chamber 10 Liquid chamber 11 Head part, 12 Piezoelectric substrate, 13 Side wall , 14a Discharge groove, 14b Non-discharge groove 15 Drive electrode 16a Common terminal, 16b Active terminal 17 Cover plate, 18 Slit, 19 Nozzle plate K Reference direction, Cp Center point A Actuator, N nozzle, Nc Located at or near the center Nozzle Δt time difference Dw drive waveform, Ds drive signal EA end region, EA1 one end region, EA2 other end region R continuous region, CA central region,
C ₁ primary coefficient, C ₂ secondary coefficient Id image data, Sd set value, Jh time difference information, Jr region information Ps single pulse,
Z landing point, R continuous area, US upper surface, SS end surface

Claims (20)

A nozzle row in which a plurality of nozzles are arranged in a reference direction, and an actuator unit that inputs a drive signal corresponding to each of the nozzles and discharges droplets from the nozzles,
The drive signal corresponding to the nozzle located in the end region of the nozzle row has a time difference in the timing of ejecting the droplets with respect to the drive signal corresponding to the nozzle located in the central region of the nozzle row,
Liquid ejection in which the time difference of the drive signals corresponding to the nozzles near the end of the nozzle row is larger than the time difference of the drive signals corresponding to the nozzles close to the center region among the nozzles located in the end region. head. The liquid droplets ejected from the nozzle located in the end region have a speed difference with respect to the liquid droplets ejected from the nozzle located in the central region,
Among the nozzles located in the end region, the speed difference of the droplets ejected from the nozzles close to the end of the nozzle row is larger than the velocity difference of the droplets ejected from the nozzles close to the central region. The liquid ejecting head according to claim 1. The end region includes one end region and the other end region of the nozzle row,
When the center of the nozzle row in the reference direction is a center point, the nozzle located in the one end region and the nozzle located in the other end region are located at a symmetrical point with respect to the center point, 3. The liquid jet head according to claim 1, wherein the time difference between the drive signals corresponding to the two nozzles located at the symmetry point is equal.   When the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the nozzle row toward the end, the time difference of the drive signal corresponding to the nozzle located at the point of the coordinate x is the coordinate The liquid jet head according to claim 1, which is represented by a linear function of x.   When the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the nozzle row toward the end, the time difference of the drive signal corresponding to the nozzle located at the point of the coordinate x is the coordinate The liquid jet head according to claim 1, represented by a quadratic function of x. A nozzle row in which a plurality of nozzles are arranged in a reference direction, and an actuator unit that inputs a drive signal corresponding to the nozzles and discharges droplets from the nozzles,
When a continuous region in which the nozzles ejecting droplets in one cycle are continuous in the reference direction is configured, a drive signal corresponding to the nozzle located at the center of the continuous region or in the vicinity thereof is The drive signal corresponding to the nozzle located in the end region has a time difference in the droplet discharge timing,
Of the nozzles located in the end region, the time difference of the drive signal corresponding to the nozzle near the center of the continuous region or the vicinity thereof, and the drive signal corresponding to the nozzle close to the end of the continuous region. Liquid jet head with large time difference. A droplet discharged from the nozzle located in the end region has a speed difference with respect to a droplet discharged from the nozzle located at or near the center,
Of the nozzles located in the end region, the droplets ejected from the nozzle near the end of the continuous region due to the speed difference of the droplets ejected from the nozzle near the center of the continuous region or the vicinity thereof. The liquid ejecting head according to claim 6, wherein the speed difference is large. A drive unit for acquiring image data and generating the drive signal;
The liquid ejecting head according to claim 6, wherein the driving unit detects the continuous region in which the nozzles ejecting droplets from the image data of one cycle are continuous in the reference direction. The end region includes one end region and the other end region of the continuous region,
When the center of the continuous region in the reference direction is a central point, the nozzle located in the one end region and the nozzle located in the other end region are located at a symmetrical point with respect to the central point, 9. The liquid ejecting head according to claim 6, wherein the time difference between the driving signals corresponding to the two nozzles positioned at the symmetry point is equal.   When the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the continuous region toward the end, the drive signal for discharging a droplet from the nozzle located at the point of the coordinate x The liquid jet head according to claim 6, wherein the time difference is expressed by a linear function of the coordinate x.   When the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the continuous region toward the end, the drive signal for discharging a droplet from the nozzle located at the point of the coordinate x The liquid jet head according to claim 6, wherein the time difference is represented by a quadratic function of the coordinate x. A liquid jet head according to claim 1 or 6,
A moving mechanism for relatively moving the liquid ejecting head and the recording medium;
A liquid supply pipe for supplying a liquid to the liquid ejecting head;
And a liquid tank that supplies the liquid to the liquid supply pipe. Identifying the setting value;
Identifying an end region of a nozzle row in which a plurality of nozzles are arranged in a reference direction based on the set value;
Calculating a time difference for determining a discharge timing of a droplet discharged from the nozzle according to a position of the nozzle located in the end region; and
Generating a driving signal in which the time difference is set;
Supplying the drive signal to an actuator unit. The end region includes one end region and the other end region of the nozzle row, and the nozzle located in the one end region with the center in the reference direction of the nozzle row as a center point; When the nozzle located in the other end region is located at a symmetrical point with respect to the center point,
The signal processing method according to claim 13, wherein in the step of generating the driving signal, the time difference equal to each other is set in the driving signal for discharging droplets from the two nozzles located at the symmetry point. In the step of calculating the time difference,
When the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the nozzle row toward the end, the time difference when the droplet is ejected from the nozzle located at the coordinate x is coordinated The signal processing method according to claim 13 or 14, wherein the calculation is performed by a linear function of x. In the step of calculating the time difference,
When the position of the nozzle located in the end region is represented by a coordinate x that increases from the center of the nozzle row toward the end, the time difference when the droplet is ejected from the nozzle located at the coordinate x is coordinated The signal processing method according to claim 13 or 14, wherein the calculation is performed by a quadratic function of x. Identifying the setting value;
Obtaining image data; and
In a nozzle row in which a plurality of nozzles are arranged in a reference direction, detecting a continuous region in which the nozzles that discharge droplets are continuous from the acquired image data of one cycle;
Identifying an end region in the continuous region based on the set value;
Calculating a time difference for determining a discharge timing of a droplet discharged from the nozzle according to a position of the nozzle located in the end region; and
Generating a driving signal in which the time difference is set;
Supplying the drive signal to an actuator unit. The end region includes one end region and the other end region of the nozzle row, and the nozzle located in the one end region with the center of the continuous region of the nozzle row as a center point; When the nozzle located in the other end region is located at a symmetrical point with respect to the center point,
The signal processing method according to claim 17, wherein in the step of generating the drive signal, the time difference equal to each other is set in the drive signal for discharging droplets from the two nozzles located at the symmetry point. In the step of calculating the time difference,
When the position of the nozzle located in the end region is represented by a coordinate x that increases from the center to the end of the continuous region, the time difference when the droplet is ejected from the nozzle located at the coordinate x is coordinated The signal processing method according to claim 17 or 18, wherein calculation is performed using a linear function of x. In the step of calculating the time difference,
When the position of the nozzle located in the end region is represented by a coordinate x that increases from the center to the end of the continuous region, the time difference when the droplet is ejected from the nozzle located at the coordinate x is coordinated The signal processing method according to claim 17 or 18, wherein calculation is performed using a quadratic function of x.

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