LIQUID DISCHARGE APPARATUS, LIQUID DISCHARGE METHOD, AND STORAGE MEDIUM

A liquid discharge apparatus includes a head, a position changer, and circuitry. The head has a nozzle. The head discharges a liquid from the nozzle to apply the liquid onto a surface of an object. The head has a prescribed discharge condition. The position changer changes a relative position between the object and the head. The circuitry determines a linear trajectory along which the position changer moves the head based on the prescribed discharge condition, outputs a first command including multiple moving positions along the linear trajectory to the position changer to cause the position changer to move the head along the linear trajectory, and outputs a second command including multiple discharge positions to the head to cause the head to discharge the liquid at the multiple discharge positions.

CROSS-REFERENCE TO RELATED APPLICATION

BACKGROUND

Technical Field

Embodiments of the present disclosure relate to a liquid discharge apparatus, a liquid discharge method, and a storage medium storing a plurality of instructions.

Related Art

In the related art, a liquid discharge apparatus discharges and applies a liquid to an object. Such a liquid discharge apparatus is used for coating a surface of the object with the liquid.

SUMMARY

Embodiments of the present disclosure describe an improved liquid discharge apparatus that includes a head, a position changer, and circuitry. The head has a nozzle. The head discharges a liquid from the nozzle to apply the liquid onto a surface of an object. The head has a prescribed discharge condition. The position changer changes a relative position between the object and the head. The circuitry determines a linear trajectory along which the position changer moves the head based on the prescribed discharge condition, outputs a first command including multiple moving positions along the linear trajectory to the position changer to cause the position changer to move the head along the linear trajectory, and outputs a second command including multiple discharge positions to the head to cause the head to discharge the liquid at the multiple discharge positions.

According to other embodiments of the present disclosure, there are provided a liquid discharge method and a non-transitory storage medium storing a plurality of instructions which, when executed by one or more processors, causes the processors to perform the liquid discharge method. The method includes discharging a liquid from a nozzle of a head to apply the liquid onto a surface of an object. The head has a prescribed discharge condition. The method further includes changing a relative position between the object and the head, determining a linear trajectory along which the head moves based on the prescribed discharge condition, outputting a first command including multiple moving positions along the linear trajectory to move the head along the linear trajectory, and outputting a second command including multiple discharge positions to the head to discharge the liquid at the multiple discharge positions.

DETAILED DESCRIPTION

A liquid discharge apparatus according to an embodiment of the present disclosure is described with reference to the drawings. However, embodiments described below are some examples of the liquid discharge apparatus for embodying the technical idea of the present disclosure, and embodiments of the present disclosure are not limited to the embodiments described below. The dimensions, materials, and shapes of components, relative arrangements thereof, and the like described below are not intended to limit the scope of the present disclosure thereto unless otherwise specified and are only examples for explanation. The size, positional relation, and the like of components illustrated in the drawings may be exaggerated for clarity of description. In the following description, the same names and the same reference codes represent the same or equivalent components, and a detailed description thereof is omitted as appropriate.

First Embodiment

Overall Configuration of Liquid Discharge Apparatus

An overall configuration of a liquid discharge apparatus10according to a first embodiment of the present disclosure is described with reference toFIGS.1and2.FIG.1is a schematic view of the liquid discharge apparatus10, andFIG.2is a block diagram of the liquid discharge apparatus10.

As illustrated inFIGS.1and2, the liquid discharge apparatus10includes a head1, a position changer2, and a controller3. The liquid discharge apparatus10is a coating apparatus that discharges a liquid Q from the head1by an ink jet method and applies the liquid Q to an object200to coat a surface of the object200. Examples of the liquid Q include paint, ink, or the like.

The object200has an impermeable surface, such as a body of a car, a truck, or an aircraft. The impermeable surface has a property of preventing a liquid applied to the surface of the object200from permeating into the interior. However, the surface of the object200is not limited to the impermeable surface and may be a permeable surface. The object200has a curved surface having a curvature but may has a flat surface.

The head1discharges the liquid Q. The head1is a valve jet type that has a nozzle and opens and closes the nozzle to discharge the liquid Q from the nozzle to the object200. However, the head1is not limited to the valve jet type, and may be another drive type such as piezoelectric drive or electrostatic drive. Specifically, the head1is a valve jet head having one nozzle.

The position changer2changes a relative position and a relative angle between the object200and the head1in response to a command output from the controller3. The position changer2is, for example, a multi-axis drivable robot arm. That is, the position changer2changes an angle (posture) of the head1while moving the head1held at an end of the robot arm in response to the command. The position changer2is not limited to the robot arm and may include a stage that is linearly movable in three axial directions. Alternatively, the position changer2may move the object200without moving the head1, or may move both the head1and the object200.

The controller3as circuitry outputs the command to the position changer2and the head1so as to cause the position changer2to move the head1through multiple moving positions in accordance with the command and cause the head1to discharge the liquid Q at multiple discharge positions in accordance with the command.

Specifically, the controller3outputs a first command including the multiple moving positions along a linear trajectory, which is described later, to the position changer2to cause the position changer2to move the head1along the linear trajectory and output a second command including the multiple discharge positions to the head1to cause the head1to discharge the liquid Q at the multiple discharge positions.

In particular, in the present embodiment, the controller3causes the position changer2to change the relative position between the object200and the head1so that a discharge distance d between the surface of the object200and the head1in a normal direction200aof the surface of the object200is different in at least one of the multiple discharge positions.

The controller3is implemented by, for example, a personal computer (PC). The controller3is connected to the position changer2and the head1so as to communicate with each other via a wire or wirelessly. The controller3outputs a drive command Rc to the position changer2to cause the position changer2to move the head1and outputs a drive signal Hc (i.e., a discharge command) to the head1to cause the head1to discharge the liquid Q based on shape data Od.

The shape data Od is transmitted from an external device such as an external PC and indicates a shape of the object200. The shape data Od is created at the time of designing the object200or obtained by measuring the object200with a three-dimensional measuring device.

Relation Between Moving Position and Discharge Position of Head Moved by Position Changer

FIG.3is a diagram illustrating a first example (i.e., a comparative example) of a relation between a moving position Td (command position) and a discharge position P in the liquid discharge apparatus10, andFIG.4is a diagram illustrating a second example of the relation between the moving position Td and the discharge position P.FIGS.3and4illustrate the object200, multiple moving positions Td, multiple discharge positions P, a discharge distance d, and a discharge interval e.

The multiple moving positions Td are data for changing a relative position between the head1and the object200, serving as the first command indicating a position of the head1in the present embodiment. In the present embodiment, the moving position Td further includes data of a relative angle of the head1, and the position changer2changes both the relative position and the relative angle of the head1relative to the object200.

The discharge position P indicates a position of the head1when the liquid Q is discharged from the head1, serving as the second command indicating a liquid discharge timing of the head1. The discharge interval e is an interval between adjacent discharge positions among the multiple discharge positions P. The discharge interval e corresponds to, for example, a minimum interval at which the head1applies the liquid Q to the object200.

In the first example illustrated inFIG.3, the number of discharge positions P is equal to the number of moving positions Td. The controller3outputs the moving position Td to the position changer2at each of the multiple discharge positions P. The head1discharges the liquid Q from the nozzle at each of the multiple discharge positions P. AlthoughFIG.3illustrates an example in which the discharge positions P and the moving positions Td coincide with each other, the discharge positions P and the moving positions Td may not necessarily coincide with each other.

In the first example illustrated inFIG.3, since the controller3instructs the position changer2in the discharge distance d at each of the multiple moving positions Td, the discharge distance d at each of the multiple discharge positions P is substantially the same discharge distance d0. That is, the discharge distances d are uniform at the multiple discharge positions P.

When the number of discharge positions P is equal to the number of moving positions Td as in the first example, the discharge distances d are uniform, and thus the head1can discharge the liquid Q in the normal direction of the surface of the object200. Accordingly, the amount of the liquid Q applied to the surface of the object200can be substantially uniform. However, on the other hand, since the position changer2changes the relative position and the relative angle of the head1at each of the multiple discharge positions P so as to keep the discharge distance d constant, the moving speed of the head1may decrease. As a result, the productivity of the liquid discharge apparatus10may decrease.

On the other hand, in the second example illustrated inFIG.4, many of the multiple moving positions Td are skipped as compared withFIG.3, and only three moving positions Td1, Td2, and Td3 remain. That is, the controller3determines the linear trajectory through the multiple moving positions (e.g., the moving positions Td1, Td2, and Td3). Note that the linear trajectory may change in the direction thereof and may include a corner (e.g., the moving position Td2 illustrated inFIG.4) when the object200has a curved surface. The term “skipped” is synonymous with “thinned out,” “omitted,” and “deleted” in the present disclosure. In other words, the three moving positions Td1, Td2, and Td3 are determined from the multiple moving position, and the other moving positions disposed in intervals between the moving positions Td1 and Td2, and between the moving positions Td2 and Td3 are skipped. The intervals can be determined in advance, for example, by a user or based on the shape data Od (i.e., predetermined intervals). The predetermined intervals are not necessarily constant and may varies, for example, the interval between the moving positions Td1 and Td2, and the interval between the moving positions Td2 and Td3.

InFIG.4, blank circles between the moving position Td1 and the moving position Td2 indicate the discharge positions P. That is, the discharge position P includes the positions of the blank circles between the moving position Td1 and the moving position Td2, the positions of the blank circles between the moving position Td2 and the moving position Td3, and the positions of the moving positions Td1, Td2, and Td3. The controller3acquires data of the multiple discharge positions P by calculation based on the multiple moving positions Td and the shape data Od. The head1discharges the liquid Q at each of the multiple discharge positions P while being moved from the moving position Td1 to the moving position Td2 by the position changer2.

At each of the moving positions Td1, Td2, and Td3, the position changer2changes the relative position of the head1relative to the object200so as to set the discharge distance d to the discharge distance d0. In addition, the position changer2changes the relative angle of the head1relative to the object200so as to discharge the liquid Q from the head1in a direction parallel to the normal direction of the surface of the object200.

On the other hand, the position changer2does not adjust the relative position and the relative angle of the head1between the moving position Td1 and the moving position Td2. The head1linearly moves between the moving position Td1 and the moving position Td2, and discharges the liquid Q at the multiple discharge positions P on a straight line passing through the moving position Td1 and the moving position Td2 along the linear trajectory. Since the head1linearly moves between the moving position Td1 and the moving position Td2, when the object200has a curved surface, the discharge distance d is different at each discharge position P due to the difference between the curved surface and the straight line. For example, the discharge distance d1 which is the distance between the object200and the head1in a normal direction200a1at the discharge position P1, the discharge distance d2 which is the distance between the object200and the head1in a normal direction200a2at the discharge position P2, and the discharge distance d0 are different from each other. That is, in the second example illustrated inFIG.4, the discharge distance d is different at the multiple discharge positions P.

In the present embodiment, some of the multiple moving positions Td are skipped as in the second example illustrated inFIG.4, and the position changer2does not adjust the discharge distance d and the relative angle at each of the multiple discharge positions P, thereby preventing the productivity of the liquid discharge apparatus10from decreasing. When some of the multiple moving positions Td are skipped, the discharge distances d are uneven, and the amount of the liquid Q applied to the surface of the object200may be nonuniform. As a result, the quality of liquid application by the liquid discharge apparatus may be deteriorated. On the other hand, in the present embodiment, the threshold conditions are set for each of the discharge distance d and the relative angle to keep the desired quality of liquid application.

Some of the multiple moving positions Td are skipped while maintaining the discharge distance d and the relative angle within the threshold conditions to keep the desired quality of liquid application, thereby preventing the decrease in productivity while keeping the desired quality of liquid application.

FIG.5is a diagram illustrating the discharge distance d between the object200and the head1. The maximum distance dx is the maximum of the discharge distance d that is allowable to keep the desired quality of liquid application (i.e., a maximum dischargeable distance). The minimum distance dn is the minimum of the discharge distance d that is allowable to keep the desired quality of liquid application (i.e., a minimum dischargeable distance). Some of the multiple moving positions Td are skipped so as to maintain the discharge distance d at each of the multiple discharge positions P within a range between the minimum distance dn and the maximum distance dx, thereby keeping the desired quality of liquid application. The maximum distance dx and the minimum distance dn can be determined in advance so as not to deteriorate the quality of liquid application, for example, by a user or based on the shape data Od.

FIG.6is a diagram illustrating a relative angle A between the object200and the head1. The maximum angle Ax is the maximum of the relative angle A that is allowable to keep the desired quality of liquid application (i.e., a maximum dischargeable angle). The minimum angle An is the minimum of the relative angle A that is allowable to keep the desired quality of liquid application (i.e., a minimum dischargeable angle). Some of the multiple moving positions Td are skipped so as to maintain the relative angle A at each of the multiple discharge positions P within a range between the minimum angle An and the maximum angle Ax, thereby keeping the desired quality of liquid application. The maximum angle Ax and the minimum angle An can be determined in advance so as not to deteriorate the quality of liquid application, for example, by a user or based on the shape data Od.

Configuration of Controller

Example of Hardware Configuration

FIG.7is a block diagram illustrating a hardware configuration of the controller3. The controller3includes a central processing unit (CPU)31, a read only memory (ROM)32, a random access memory (RAM)33, a hard disk drive (HDD)/solid state drive (SSD)34, a connection interface (I/F)35, and a communication I/F36. These components are electrically connected to each other via a system bus B.

The CPU31uses the RAM33as a work area and executes a program stored in the ROM32to control the overall operation of the controller3.

The ROM32is a non-volatile memory that stores a program for controlling, for example, a recording operation to the CPU31and other fixed data. The RAM33is a volatile memory that temporarily stores various kinds of data.

The HDD/SSD34is a nonvolatile memory that stores coating area data, the shape data Od of the body of the object200, and the like. The CPU31may read the data stored in the HDD/SSD34and uses the data to execute the program.

The connection I/F35connects the controller3to an external equipment. Examples of the external equipment include the position changer2and the head1. The communication I/F36allows the controller3to communicate with the external device such as the external PC.

Example of Functional Configuration of Controller

FIG.8is a block diagram illustrating a functional configuration of the controller3according to the first embodiment. The controller3includes a communication unit301, an input/output unit302, a command data generation unit303, a skipping unit304, a verification unit305, a command unit306, and a discharge control unit307.

The controller3implements functions of the communication unit301and the input/output unit302with the communication I/F36and the connection I/F35, respectively. The controller3executes a program stored in the ROM32with the CPU31to implement the functions of the command data generation unit303, the skipping unit304, the verification unit305, the command unit306, and the discharge control unit307.

Note that the controller3may include functional units other than those units described above. Components other than the controller3may have some of the above-described functions of the controller3. The components other than the controller3include the position changer2, the head1, and the external PC. The controller3and the components other than the controller3may be dispersed to implement some of the above-described functions of the controller3. Alternatively, the controller3may implement at least a part of the functions implemented by the CPU31with an electric circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

The communication unit301controls communication of signals and data between the controller3and the external device such as the external PC. The input/output unit302controls input and output of signals and data between the controller3, and the position changer2and the head1.

The command data generation unit303executes a process of generating data of the multiple moving positions Td. For example, the command data generation unit303generates the multiple moving positions Td based on the shape data Od input via the communication unit301.

The skipping unit304executes a process of skipping some of the multiple moving positions Td disposed in the predetermined intervals. The skipping unit304outputs data of the rest of the multiple moving positions Td, which is not skipped, as a result of skipping to the verification unit305.

The verification unit305executes a process of verifying whether to obtain the desired quality of liquid application when the liquid Q is discharged to the object200at the multiple discharge positions P acquired based on the rest of the multiple moving positions Td. When the verification unit305verifies that the desired quality of liquid application can be obtained, the verification unit305outputs data corresponding to the rest of the multiple moving positions Td to the command unit306and outputs data corresponding to the multiple discharge positions P to the discharge control unit307.

The controller3performs verification by the verification unit305based on the discharge distance d or the relative angle A. As described above, the controller3skips some of the multiple moving positions Td disposed in the predetermined intervals by the skipping unit304in accordance with the result of verification by the verification unit305.

The command unit306outputs the drive command Rc to the position changer2based on the rest of the multiple moving positions Td input from the verification unit305to change the relative position and the relative angle between the object200and the head1.

The discharge control unit307controls the discharge of the liquid Q from the head1at the multiple discharge positions P.

Example of Moving Position

FIG.9is a diagram illustrating an example of the moving position Td generated by the command data generation unit303.

InFIG.9, a command “MOVJ” means a joint interpolation command. The joint interpolation is an interpolation command corresponding to a fast-forward command in a numerical control (NC) machine tool. Since a servo motor of each joint of the robot arm is likely to operates with easy movement in the joint interpolation, the path of the head1by the interpolation command from the current coordinates to the moving position follows the process by the robot arm. Arguments “X=100 Y=50 Z=0” means X, Y, and Z coordinate values corresponding to the three-dimensional relative position of the head1. Arguments “A=0 B=45 C=0” means the three-dimensional relative angle of the head1.

A command “MOVL” means a linear interpolation command. Arguments “X=200 Y=80 Z=11” means X, Y, and Z coordinate values corresponding to the three-dimensional relative position of the head1, and arguments “A=0 B=30 C=0” means the three-dimensional relative angle of the head1. The linear interpolation corresponds to a linear interpolation command in the NC machine tool. The head1is moved from the current coordinates to the designated point along a linear trajectory (the straight line) by the linear interpolation command. In the present embodiment, the command “MOVL” is preferably used as the first command to precisely drive the robot arm as the position changer2.

Example of Process Executed by Controller

Process of Generating Moving Position

FIG.10is a flowchart illustrating an example of a process of generating the moving position Td by the controller3. The controller3starts the process illustrated inFIG.10in response to an instruction to start the process of generating the moving position Td, which is input by a user, for example. The user can input the instruction with a control panel or the like of the liquid discharge apparatus10.

In step S101, the controller3receives the shape data Od of the object200from an external PC or the like via the communication unit301.

In step S102, the controller3determines the linear trajectory based on the shape data Od and causes the command data generation unit303to generate data of the multiple moving positions Td along the linear trajectory.

In step S103, the controller3causes the verification unit305to verify whether to obtain the desired quality of liquid application when the liquid Q is discharged to the object200in accordance with each of the multiple moving positions Td generated by the command data generation unit303.

In step S104, the controller3causes the verification unit305to determine whether the verification result is acceptable. In step S104, when the verification unit305determines that the verification result is acceptable (Yes in step S104), the controller3executes the process of step S105. On the other hand, when the verification unit305determines that the verification result is not acceptable (No in step S104), the controller3executes the process of step S102again.

In step S105, the controller3causes the skipping unit304to skip some of the multiple moving positions Td disposed in the predetermined intervals. In other words, the controller3reduce the number of the multiple moving positions Td on the linear trajectory.

In step S106, the controller3causes the verification unit305to verify whether to obtain the desired quality of liquid application when the liquid Q is discharged to the object200in accordance with each of the rest of the multiple moving positions Td, which is not skipped by the skipping unit304.

In step S107, the controller3causes the verification unit305to determine whether the verification result is acceptable.

In step S107, when the verification unit305determines that the verification result is acceptable (Yes in step S107), the controller3executes the process of step S109. On the other hand, when the verification unit305determines that the verification result is not acceptable (No in step S107), in step S108, the controller3cancels the skipping of some of the multiple moving positions Td skipped in step S105. Thereafter, the controller3executes the process of step S105again. In this case, the controller3may determine another linear trajectory different from the linear trajectory to generate moving positions Td, and the skipping unit304skips the newly generated moving positions Td different from the some of the multiple moving positions Td that are previously skipped in step S105.

In step S109, the controller3determines whether to end the process. The controller3can determine to end the process in accordance with an input or the like by a user using the control panel of the liquid discharge apparatus10. When the controller3determines to end the process in step S109(Yes in step S109), the process ends. When the controller3determines not to end the process in step S109(No in step S109), the controller3continues the process from step S105again. As described above, the controller3can generate the data of the moving positions Td.

Verification Process

FIG.11is a flowchart illustrating an example of a verification process executed by the controller3. The controller3starts the verification process illustrated inFIG.11at the timing of step S103or step S106ofFIG.10.

In step S111, the controller3causes the verification unit305to acquire data of the discharge distance d and the relative angle A at each of the multiple discharge positions P by calculation.

In step S112, the controller3causes the verification unit305to determine whether the discharge distance d at each of the multiple discharge positions P is within the range between the minimum distance dn and the maximum distance dx.

In step S112, when the verification unit305determines that the discharge distance d remains between the minimum distance dn and the maximum distance dx (Yes in step S112), the controller3proceeds to the process of step S113. When the verification unit305determines that the discharge distance d does not remain between the minimum distance dn and the maximum distance dx (No in step S112), the controller3proceeds to the process of step S115to determine that the verification result is not acceptable.

In step S113, the controller3causes the verification unit305to determine whether the relative angle A at each of the multiple discharge positions P is within the range between the minimum angle An and the maximum angle Ax.

In step S113, when the verification unit305determines that the relative angle A remains between the minimum angle An and the maximum angle Ax (Yes in step S113), the controller3proceeds to the process of step S114to determine that the verification result is acceptable. When the verification unit305determines that the relative angle A does not remain between the minimum angle An and the maximum angle Ax (No in step S113), the controller3proceeds to the process of step S115to determine that the verification result is not acceptable.

As described above, the controller3executes the process of verifying whether to obtain the desired quality of liquid application when the liquid Q is discharged to the object200at the multiple discharge positions P acquired based on the multiple moving positions Td.

Example of Operation of Liquid Discharge Apparatus

FIG.12is a timing chart illustrating an example of an operation of the liquid discharge apparatus10. InFIG.12, a position signal Ec indicates an output signal from a rotary encoder of the position changer2. The controller3acquires the relative position and the relative angle of the head1held by the position changer2based on the position signal Ec by calculation.

A synchronization signal Sn is a signal for synchronizing the change of the relative position and the relative angle by the position changer2with the discharge of the liquid Q by the head1. The synchronization signal Sn is output from the position changer2and input to the controller3.

An interval signal Ck is a signal serving as a reference for defining the minimum interval of liquid application by the liquid discharge apparatus10. For example, when the minimum interval of liquid application is 100 dots per inch (dpi) (i.e., 0.254 mm), every time the head1moves 0.254 mm, the interval signal Ck of one pulse is output from the controller3to the head1.

The drive signal Hc (i.e., the discharge command) is a signal for discharging the liquid Q from the head1. A delay td indicates a delay time with respect to the interval signal Ck, and the discharge time to indicates a time during which the nozzle of the head1is opened to discharge the liquid Q. The delay td varies depending on the discharge distance d, a discharge speed, and the like. The discharge time to varies depending on the amount of the liquid Q to be discharged.

Effects of Liquid Discharge Apparatus

As described above, the liquid discharge apparatus10includes the head1, the position changer2, and the controller3. The head1has a nozzle. The head1discharges the liquid Q from the nozzle to apply the liquid Q onto a surface of the object200. The head1has a prescribed discharge condition. The position changer2changes the relative position between the object200and the head1. The controller3determines a linear trajectory along which the position changer2moves the head1based on the prescribed discharge condition, outputs a first command including multiple moving positions Td along the linear trajectory to the position changer21to cause the position changer2to move the head1along the linear trajectory and outputs a second command including multiple discharge positions P to the head1to cause the head1to discharge the liquid Q at multiple discharge positions P.

Thus, the controller3controls the change of the relative position by the position changer2so that the discharge distance d between a surface of the object200and the head1in a normal direction of the surface of the object200is different in at least one of the multiple discharge positions P. The liquid discharge apparatus10does not adjust the relative position of the head1so as to make the discharge distance d uniform at each of the multiple discharge positions P, thereby preventing the moving speed of the head1from decreasing. Accordingly, the liquid discharge apparatus10having good productivity can be provided.

In the present embodiment, the controller3skips some of the multiple moving positions Td disposed in predetermined intervals based on the discharge distance d. In other words, the controller3reduces the number of the multiple moving positions Td on the linear trajectory based on the discharge distance d between the surface of the object200and the head1in the normal direction200aof the surface of the object200. Since some of the multiple moving positions Td are skipped, the number of times of adjusting the discharge distance d can be reduced. Accordingly, the moving speed of the head1can be prevented from decreasing, and the liquid discharge apparatus10having good productivity can be provided.

In the present embodiment, the controller3skips some of the multiple moving positions Td when the discharge distance d at each of the multiple discharge positions remains between the predetermined minimum distance dn and the predetermined maximum distance dn. In other words, the prescribed discharge condition includes the maximum dischargeable distance and the minimum dischargeable distance, and the controller3reduces the number of the multiple moving positions Td at which the discharge distance d between the surface of the object200and the head1in the normal direction200aof the surface of the object200is within a range between the maximum dischargeable distance and the minimum dischargeable distance for each of the multiple discharge positions. Some of the multiple moving positions Td are skipped within the conditions to keep the desired quality of liquid application by the liquid discharge apparatus10, thereby preventing the decrease in productivity of the liquid discharge apparatus10while keeping the desired quality of liquid application.

In the present embodiment, the position changer2further changes the relative angle A between the object200and the head1. The controller3changes at least one of the relative position or the relative angle A at a position the linear trajectory changes to make the discharge distance d different in at least one of the multiple moving positions Td. The liquid discharge apparatus10does not adjust the relative position and the relative angle A of the head1so as to make the discharge distance d uniform at each of the multiple discharge positions P, thereby preventing the moving speed of the head1from decreasing. Accordingly, the liquid discharge apparatus10having good productivity can be provided.

In the present embodiment, the controller3skips some of the multiple moving positions Td disposed in predetermined intervals based on the relative angle A. In other words, the controller3reduces the number of the multiple moving positions Td on the linear trajectory based on the relative angle A. Since some of the multiple moving positions Td are skipped, the number of times of adjusting the relative angle A can be reduced. Accordingly, the moving speed of the head1can be prevented from decreasing, and the liquid discharge apparatus10having good productivity can be provided.

In the present embodiment, the controller3skips some of the multiple moving positions Td when the relative angle A at each of the multiple discharge positions remains between the predetermined minimum angle An and the predetermined maximum angle An. In other words, the prescribed discharge condition includes the maximum dischargeable angle and the minimum dischargeable angle, and the controller3reduces the number of the multiple moving positions Td at which the discharge distance d between the surface of the object200and the head1in the normal direction200aof the surface of the object200is within a range between the maximum dischargeable angle and the minimum dischargeable angle for each of the multiple discharge positions. Some of the multiple moving positions Td are skipped within the conditions to keep the desired quality of liquid application by the liquid discharge apparatus10, thereby preventing the decrease in productivity of the liquid discharge apparatus while keeping the desired quality of liquid application.

Second Embodiment

A liquid discharge apparatus10aaccording to a second embodiment of the present disclosure is described. The same components as those of the first embodiment are denoted by the same reference numerals, and redundant description thereof is appropriately omitted.

In the present embodiment, the head1ahas multiple nozzles. The controller3skips some of the multiple moving positions Td based on the discharge distance d or the relative angle A at each of the multiple nozzles.

Configuration of Head

FIGS.13and14are schematic views of a head1aincluded in a liquid discharge apparatus10a.FIG.13is a perspective view of the head1a, andFIG.14is a cross-sectional view of the head1ataken along a plane51inFIG.13.

As illustrated inFIGS.13and14, the head1aincludes a housing100, a supply port101, a collection port102, a connector103, and multiple discharge modules110. In the head1a, the liquid Q pressurized from the outside is supplied to the discharge modules110through the supply port101, and the liquid Q that is not discharged is drained to the outside through the collection port102. The connector103is disposed in the housing100to receive the drive signal Hc from the controller3.

The multiple discharge modules110are arranged in one row or a plurality of rows in the housing100. The discharge module110includes a nozzle plate111, a channel122, and a piezoelectric element124. The nozzle plate111has multiple nozzles121from which the liquid Q is discharged. The nozzle plate111is joined to the housing100. The channel122communicates with the nozzle121to supply the pressurized liquid Q to the nozzle121. Further, the channel122is shared with the multiple liquid discharge modules110in the housing100. The piezoelectric element124drives a needle-shaped valve that opens and closes the nozzle121.

The head1ais a valve jet type that individually opens and closes the multiple nozzles121to discharge the liquid Q from each of the multiple nozzles121to the object200. The discharge module310may temporarily stop draining the liquid Q from the collection port102while discharging the liquid Q to the object200from the nozzle121to prevent a decrease in a liquid discharge efficiency from the nozzle121. The liquid discharge apparatus10aincludes, but not limited to, the head1aof valve jet type, and may include a head of another type such as piezoelectric drive or electrostatic drive.

FIG.15is a timing chart illustrating an example of the operation of the liquid discharge apparatus10a. The position signal Ec, the synchronization signal Sn, and the interval signal Ck are the same as those inFIG.12.

The drive signal Hc_n1 is a signal for discharging the liquid Q from a first nozzle among the multiple nozzles121of the head1a. The drive signal Hc_n2 is a signal for discharging the liquid Q from a second nozzle among the multiple nozzles121of the head1a. The drive signal Hc_n3 is a signal for discharging the liquid Q from a third nozzle among the multiple nozzles121of the head1a. The delay td and the discharge time to are the same as those inFIG.12. In the present embodiment, three drive signals Hc are exemplified, but the number of drive signals Hc can be appropriately changed in accordance with the number of nozzles included in the head1a.

As described above, in the present embodiment, the head1ahas the multiple nozzles121. The controller3skips some of the multiple moving positions Td based on the discharge distance d or the relative angle A at each of the multiple nozzles121. In other words, the controller3reduces the number of the multiple moving positions Td on the linear trajectory based on the discharge distance d between the surface of the object200and the head1in the normal direction200aof the surface of the object200for each of the multiple nozzles. Accordingly, even when the head1ahas the multiple nozzles121, the liquid discharge apparatus10adoes not adjust the relative position of the head1aso as to make the discharge distance d uniform at each of the multiple discharge positions P, thereby preventing the moving speed of the head1afrom decreasing. Accordingly, the liquid discharge apparatus10ahaving good productivity can be provided.

Although the embodiments have been described above, embodiments of the present disclosure are not limited to the above embodiments. That is, various modifications and improvements can be made within the scope of the present disclosure.

In the above-described embodiments, examples of the liquid discharged from the head1include a solution, a suspension, or an emulsion that contains, for example, a solvent, such as water or an organic solvent, a colorant, such as dye or pigment, a functional material, such as a polymerizable compound, a resin, or a surfactant, a biocompatible material, such as DNA, amino acid, protein, or calcium, or an edible material, such as a natural colorant. These liquids can be used for, e.g., inkjet ink, coating paint, surface treatment solution, a liquid for forming components of electronic element or light-emitting element or a resist pattern of electronic circuit, or a material solution for three-dimensional fabrication.

The object200represents a material onto which liquid is adhered and fixed, a material into which liquid is adhered to permeate, or the like. Specific examples of the “material onto which liquid can adhere” include, but are not limited to, a body of a vehicle, a construction material, a recording medium such as a paper sheet, recording paper, a recording sheet of paper, a film, or cloth, an electronic component such as an electronic substrate or a piezoelectric element, and a medium such as layered powder, an organ model, or a testing cell. The “material onto which liquid can adhere” includes any material to which liquid adheres, unless particularly limited.

Embodiments also include a liquid discharge method. A liquid discharge method includes discharging a liquid from a nozzle of a head to apply the liquid onto a surface of an object. The head has a prescribed discharge condition. The method further includes changing a relative position between the object and the head, determining a linear trajectory along which the head moves based on the prescribed discharge condition, outputting a first command including multiple moving positions along the linear trajectory to move the head along the linear trajectory, and outputting a second command including multiple discharge positions to the head to discharge the liquid at multiple discharge positions. Accordingly, a discharge distance between a surface of the object and the head in a normal direction of the surface of the object is different in at least one of the multiple discharge positions. Such a liquid discharge method can provide operational effects equivalent to those of the above-described liquid discharge apparatus.

Embodiments also include a storage medium storing computer-readable program instructions and a computer-readable program product. For example, a non-transitory storage medium storing a plurality of instructions which, when executed by one or more processors, causes the processors to perform a method including discharging a liquid from a nozzle of a head to apply the liquid onto a surface of an object. The head has a prescribed discharge condition. The method further includes changing a relative position between the object and the head, determining a linear trajectory along which the head moves based on the prescribed discharge condition, outputting a first command including multiple moving positions along the linear trajectory to move the head along the linear trajectory, and outputting a second command including multiple discharge positions to the head to discharge the liquid at multiple discharge positions. Accordingly, a discharge distance between a surface of the object and the head in a normal direction of the surface of the object is different in at least one of the multiple discharge positions. A storage medium or a computer-readable program product including such program code can provide operational effects equivalent to those of the above-described liquid discharge apparatus.

As described above, according to the present disclosure, the liquid discharge apparatus having good productivity can be provided.