Patent Description:
In the related art, a liquid discharge apparatus is known to apply liquid discharged from a head to an application surface. In order to apply liquid to an object having a three-dimensional curved surface (curved in two directions), for example, a liquid discharge apparatus has a configuration in which a reference length is compared with a curve length immediately below a plurality of nozzles of an inkjet head at a position of the three-dimensional curved surface on which liquid is to be discharged. In the liquid discharge apparatus, the amount of liquid droplets to be discharged from the plurality of nozzles is changed according to the ratio between the reference length and the curve length (for example, <CIT>). The liquid discharge apparatus is desired to be excellent in quality of liquid application to an application surface.

<CIT> discloses a coating device for easily forming a high-quality parting line without increasing the number of stages and necessary to materials which avoids degradation of coating quality.

The dependent claims relate to preferred embodiments of the invention.

An object of the present invention is to provide a liquid discharge apparatus excellent in quality of liquid application to an application surface.

Embodiments of the present invention described herein provide a novel liquid discharge apparatus includes a head and a controller. The head discharges liquid to apply the liquid to an application surface. The controller controls discharge of the liquid from the head based on a vertical height of an application position at which the liquid is applied on the application surface.

Embodiments of the present invention described herein provide a novel liquid discharge method to be executed by a liquid discharge apparatus. The method includes discharging and controlling. The discharging discharges liquid by a head to apply the liquid to an application surface. The controlling, by a controller, controls discharge of the liquid from the head based on a vertical height of an application position at which the liquid is applied to the application surface.

Embodiments of the present invention described herein provide a novel carrier medium carrying computer-readable program code that causes a liquid discharge apparatus to perform discharging and controlling. The discharging discharges liquid by a head to apply the liquid to an application surface. The controlling, by a controller, controls discharge of the liquid from the head based on a vertical height of an application position at which the liquid is applied to the application surface.

Referring now to the drawings, embodiments of the present invention are described below.

Hereinafter, a liquid discharge apparatus according to embodiments of the present invention are described in detail with reference to the drawings. However, the embodiments described below are some examples of the liquid discharge apparatus for embodying the technical idea of the present invention, and the embodiments of the present invention are not limited to the embodiments described below. Further, the size, material, and shape of components and the relative positions of the arranged components are given by way of example in the following description, and the scope of the present invention is not limited thereto but specified by the appended claims. Note that the size of these elements and the relative positions of these elements may be exaggerated for purposes of illustration in the drawings. In the description given below with reference to the drawings, like reference signs denote like elements, and overlapping description may be simplified or omitted as appropriate.

In the drawings illustrated below, directions may be indicated by X-axis, Y-axis, and Z-axis. An X-direction along the X-axis indicates a main scanning direction which is a moving direction of a carriage provided for the liquid discharge apparatus according to embodiments of the present invention. A Y-direction along the Y-axis indicates a sub-scanning direction intersecting the main scanning direction. A Z-direction along the Z-axis indicates a direction intersecting each of the X-direction and the Y-direction.

A direction in which an arrow points in the X-direction is denoted as +X-direction, and a direction opposite to the +X-direction is denoted as -X-direction. A direction in which an arrow points in the Y-direction is denoted as +Y-direction, and a direction opposite to the +Y-direction is denoted as -Y-direction. A direction in which an arrow points in the Z-direction is referred to as a +Z-direction, and a direction opposite to the +Z-direction is denoted as a -Z-direction. In the embodiments of the present invention described below, the Y-direction is along the vertical direction, and the Z-direction is along the horizontal direction substantially orthogonal to the vertical direction as an example. However, the above-described directions do not limit the orientation of the liquid discharge apparatus in use, and the liquid discharge apparatus may be oriented in any-direction.

The configuration of a liquid discharge apparatus <NUM> according to embodiments of the present invention is described with reference to <FIG> and <FIG>. <FIG> and <FIG> are views illustrating an overall configuration of the liquid discharge apparatus <NUM>. <FIG> is a side view and <FIG> is a front view.

The liquid discharge apparatus <NUM> applies ink, which is an example of liquid, to an application surface 100a of an object <NUM>. The ink applied to the application surface 100a adheres to the application surface 100a after the ink dries. Either a continuous discharge type or a droplet discharge type can be applied to a discharge method of the liquid discharge apparatus <NUM>. Examples of the continuous discharge type include a valve method in which discharge is controlled by controlling the operation of a valve body, and a continuous method in which particles of ink continuously discharged from a nozzle are charged, bent by a deflection electrode, and sprayed onto a printing surface.

The examples of the application surface 100a include non-permeable surfaces such as bodies of cars, trucks, and airplanes. The term "non-permeable" refers to a characteristic that liquid applied to the application surface 100a of the object <NUM> does not permeate into the inside of the object <NUM>. The liquid discharge apparatus <NUM> can coat or paint a body of a car, a truck, or an aircraft by applying ink to the body. In <FIG>, an example of a flat application surface 100a is illustrated.

The application surface 100a is not limited to a surface having non-permeability and may be a surface having permeability. The application surface 100a is not limited to a flat surface and may be a surface having a curvature in the X-direction or the Y-direction. The use of the liquid discharge apparatus <NUM> is not limited to coating or painting and may be a use in which an image is formed (or printed) with ink on a recording medium such as a sheet or a film.

As illustrated in <FIG> and <FIG>, the liquid discharge apparatus <NUM> includes a head <NUM>, a mover <NUM>, and a controller <NUM>. In the liquid discharge apparatus <NUM>, the head <NUM> is disposed to face the application surface 100a of the object <NUM>.

The head <NUM> is configured to discharge liquid such as ink to applies the ink to an application surface. The head <NUM> has a plurality of nozzles arranged at predetermined intervals in the Y-direction, and applies ink discharged from each of the nozzles to the application surface 100a. The head <NUM> is disposed on a carriage <NUM>. However, the head <NUM> may not have a plurality of nozzles and may have one nozzle.

The mover <NUM> is a mechanism that relatively moves the head <NUM> and the application surface 100a along the surface of the application surface 100a. In the present embodiment, the mover <NUM> relatively moves the head <NUM> and the application surface 100a in each of the X-direction and the Y-direction along the surface of the application surface 100a. The mover <NUM> includes an X-axis rail <NUM> and a Y-axis rail <NUM>.

A Z-axis rail <NUM> holds the carriage <NUM> so that the carriage <NUM> can move in the Z-direction. The X-axis rail <NUM> holds the Z-axis rail <NUM> such that the Z-axis rail <NUM> holding the carriage <NUM> is movable in the X-direction. The Y-axis rail <NUM> holds the X-axis rail <NUM> such that the X-axis rail <NUM> is movable in the Y-direction.

A Z-direction driver <NUM> moves the carriage <NUM> in the Z-direction along the Z-axis rail <NUM>. A X-direction driver <NUM> moves the Z-axis rail <NUM> in the X-direction along the X-axis rail <NUM>. A Y-direction driver <NUM> moves the X-axis rail <NUM> in the Y-direction along the Y-axis rail <NUM>. Note that the movement of the carriage <NUM> and the head <NUM> in the Z-direction may not be parallel to the Z-direction and may be an oblique movement as long as the movement includes at least a component in the Z-direction.

The controller <NUM> is configured to control an operation of ink discharge to the application surface 100a by the liquid discharge apparatus <NUM>. The controller <NUM> is configured by a processor or an electric circuit mounted on an electric board. The controller <NUM> is electrically connected to at least each driver that drives the mover <NUM> and the head <NUM> in a wired or wireless manner. However, the electric board on which the controller <NUM> is mounted is arranged in any position, and the electric board may be arranged remotely with respect to the head <NUM>.

The liquid discharge apparatus <NUM> discharges ink from the head <NUM> toward the application surface 100a while moving the carriage <NUM> in each of the X-direction, the Y-direction, and the Z-direction to apply the ink to the application surface 100a.

More specifically, the liquid discharge apparatus <NUM> discharges the ink from the head <NUM> and applies the ink to the application surface 100a while relatively moving the head <NUM> and the application surface 100a in the X-direction which is the main scanning direction.

After one relative movement in the X-direction is completed, the liquid discharge apparatus <NUM> relatively moves the head <NUM> and the application surface 100a in the Y-direction which is the sub-scanning direction. After one relative movement in the Y-direction is completed, the liquid discharge apparatus <NUM> discharges ink from the head <NUM> while relatively moving the head <NUM> and the application surface 100a in the X-direction again, to apply the ink to the application surface 100a. The liquid discharge apparatus <NUM> repeats such relative movement in the X-direction and the Y-direction to apply ink to the application surface 100a.

In a case where the application surface 100a is a flat object along the X-direction and the Y-direction, the liquid discharge apparatus <NUM> does not perform relative movement between the head <NUM> and the application surface 100a in the Z-direction during an ink application operation. In a case where the application surface 100a has a shape in which the height differs in the Z-direction, the liquid discharge apparatus <NUM> performs relative movement between the head <NUM> and the application surface 100a in the Z-direction according to the shape of the application surface 100a during the ink application operation.

<FIG> is a block diagram illustrating an example of the hardware configuration of the controller <NUM> included in the liquid discharge apparatus <NUM>. The controller <NUM> includes a central processing unit (CPU) <NUM>, a read only memory (ROM) <NUM>, a random-access memory (RAM) <NUM>, and an interface (I/F) <NUM>. These units and components are electrically connected to each other through a system bus. The controller <NUM> is configured by, for example, a computer.

In addition, the controller <NUM> is electrically connected to the head <NUM>, the X-direction driver <NUM>, the Y-direction driver <NUM>, the Z-direction driver <NUM>, a storage device <NUM>, a display device <NUM>, and an operation panel <NUM>.

The CPU <NUM> uses a RAM <NUM> as a work area and executes a program stored in the ROM <NUM> to control the overall operation of the controller <NUM>.

The ROM <NUM> is a non-volatile memory that stores a program for executing control such as a recording operation to the CPU <NUM> and stores other fixed data.

The RAM <NUM> is a volatile memory that temporarily stores, for example, image data such as patterns and characters to be drawn on the application surface 100a and shape information of the body of the object <NUM>.

The I/F <NUM> is an interface that enables communication between an external apparatus such as a host personal computer (PC) and the controller <NUM>.

The storage device <NUM> is an external storage device such as a hard disk drive (HDD) or a solid state drive (SSD) that stores setting values set in advance. The information stored in the storage device <NUM> may be read and used by the CPU <NUM> when the CPU <NUM> executes a program.

Under the control of the controller <NUM>, the display device <NUM> displays, for example, a setting screen for ink application conditions by the liquid discharge apparatus <NUM>.

The operation panel <NUM> is an operation input device such as a touch screen, a keyboard, or a mouse that receives an operation of the liquid discharge apparatus <NUM>. The operation panel <NUM> is used to input values (coordinates) for identifying an area where ink is discharged onto the application surface 100a, to input a movement speed of the carriage <NUM>, to input values for identifying image information and three-dimensional coordinate information (body information) used for applying ink onto the application surface 100a, and to input a distance between the head <NUM> and the application surface 100a.

Note that the display device <NUM> and the operation panel <NUM> may be integrated into a single screen such as a touch screen.

The X-direction driver <NUM> drives the carriage <NUM> in the X-direction based on instructions from the controller <NUM>. The Y-direction driver <NUM> drives the carriage <NUM> in the Y-direction based on instructions from the controller <NUM>. The Z-direction driver <NUM> drives the carriage <NUM> in the Z-direction based on instructions from the controller <NUM>.

The controller <NUM> controls the operations of the X-direction driver <NUM> and the Y-direction driver <NUM> to control the movement of the carriage <NUM>, in which the head <NUM> is included, in the X-direction and the Y-direction. In addition, the controller <NUM> controls the operation of the Z-direction driver <NUM> to control the movement of the head <NUM> in the Z-direction with respect to the carriage <NUM>. Further, the controller <NUM> controls discharge of ink from the head <NUM>.

<FIG> is a diagram illustrating an example of the configuration of a supply unit <NUM> of the liquid discharge apparatus <NUM>. The supply unit <NUM> supplies ink to the head <NUM>.

The head <NUM> includes a head 300Y that discharges yellow (Y) ink, a head <NUM> that discharges magenta (M) ink, a head 300C that discharges (C) ink, and a head <NUM> that discharges black (K) ink. In a case where the heads 300Y, <NUM>, 300C, and <NUM> are not distinguished from each other, the heads 300Y, <NUM>, 300C, and <NUM> are collectively referred to as the heads <NUM> in the description below.

The heads <NUM> may further include another head, such as a head 300Q that discharges overcoating ink and a head 300P that discharges primer ink or white ink. The supply unit <NUM> supplies ink of each color to the head <NUM> of each color.

The supply unit <NUM> includes ink tanks 330Y, <NUM>, 330C, and <NUM> (hereinafter referred to as ink tanks <NUM> unless distinguished) as sealed containers that stores inks <NUM> of magenta, cyan, yellow, and black to be discharged from the heads <NUM>, 300C, 300Y, and <NUM>, respectively. The ink tank <NUM> and an ink inlet (supply port) of the head <NUM> are connected to each other through a tube <NUM> so that ink <NUM> flows.

On the other hand, the ink tank <NUM> is connected to a compressor <NUM> through a pipe <NUM> including an air regulator <NUM>, and the compressor <NUM> supplies pressurized air. Accordingly, the pressurized ink <NUM> of each color is supplied to the ink inlet of each head <NUM>, and the liquid discharge apparatus <NUM> discharges the ink <NUM> from each nozzle of the head <NUM>.

<FIG> and <FIG> are schematic views illustrating an example of the configuration of the head <NUM>. <FIG> is a perspective view of the head <NUM>, and <FIG> is a cross-sectional view of the head <NUM> cut by a plane S1 of <FIG>.

The head <NUM> includes a plurality of discharge modules <NUM> arranged in one or a plurality of rows in a housing <NUM>.

The head <NUM> includes a supply port <NUM> and a collection port <NUM>. The supply port <NUM> supplies pressurized ink from the outside to each discharge module <NUM>, and the collection port <NUM> sends out non-discharged ink to the outside. The housing <NUM> is provided with a connector <NUM>.

The discharge module <NUM> includes a nozzle plate <NUM>, a channel <NUM>, and piezoelectric elements <NUM>. Nozzles <NUM> that discharge liquid are formed in the nozzle plate <NUM>. The channel <NUM> communicates with the nozzles <NUM> to supply pressurized liquid to the nozzles <NUM>. Each piezoelectric element <NUM> drives a valve body having a needle shape to open and close the nozzle <NUM>.

The nozzle plate <NUM> is joined to the housing <NUM>. The channel <NUM> is a channel common to the plurality of discharge modules <NUM> formed in the housing <NUM>. The pressurized ink is supplied from the supply port <NUM>, and non-discharged ink is sends out from the collection port <NUM>. Note that the send-out of ink from the collection port <NUM> may be temporarily stopped to prevent a decrease in the discharging rate of ink from the nozzles <NUM> during a period in which ink is discharged to the application surface 100a.

<FIG> is a diagram illustrating an example of the functional configuration of the controller <NUM>. The controller <NUM> includes an acquisition unit <NUM>, an ink amount determination unit <NUM>, a discharge control unit <NUM>, and a movement control unit <NUM>.

The controller <NUM> controls the operation of the liquid discharge apparatus <NUM> to apply ink to the application surface 100a. In particular, in the present embodiment, the controller <NUM> causes the ink amount determination unit <NUM> to determine the amount of the ink <NUM> to be discharged from the head <NUM> based on the shape information of the application surface 100a acquired from a host PC via the acquisition unit <NUM> and causes the discharge control unit <NUM> to discharge the ink <NUM> from the head <NUM>. In addition, the controller <NUM> causes the movement control unit <NUM> to control the mover <NUM> based on the shape information of the application surface 100a to relatively move the head <NUM> and the application surface 100a.

The controller <NUM> implements the respective functions of the acquisition unit <NUM>, the ink amount determination unit <NUM>, the discharge control unit <NUM>, and the movement control unit <NUM> by the CPU <NUM> deploying a program stored in the ROM <NUM> to the RAM <NUM> and executing the program.

Note that at least some of the functions of the controller <NUM> may be implemented by any other element such as the head <NUM> than the controller <NUM>. Alternatively, at least some of the functions of the controller <NUM> may be implemented by the controller <NUM> and any other element than the controller <NUM> in a distributed manner.

The acquisition unit <NUM> inputs shape information Sd of the application surface 100a from an external device such as a host PC and acquires the shape information Sd. The shape information Sd is three-dimensional information representing the shape of the application surface 100a. The acquisition unit <NUM> may read the shape information Sd stored in advance in the storage device <NUM> to acquire the shape information Sd. Alternatively, the liquid discharge apparatus <NUM> may include a detection unit to detect the shape of the application surface 100a, and the acquisition unit <NUM> may receive, from the detection unit, the shape information Sd of the application surface 100a detected by the detection unit to acquire the shape information Sd. The acquisition unit <NUM> outputs the acquired shape information Sd to the ink amount determination unit <NUM>.

The ink amount determination unit <NUM> determines an ink amount m (amount of liquid) to be discharged from the head <NUM> based on the shape information Sd input from the acquisition unit <NUM>. In the present embodiment, the ink amount determination unit <NUM> determines the ink amount m so that the ink amount m increase as a height h along the vertical direction (i.e., a vertical height h) of an application position P at which the ink <NUM> is applied on the application surface 100a increases.

For example, the ink amount determination unit <NUM> refers to a table <NUM> stored in the storage device <NUM> and determines the ink amount m based on the shape information Sd and the vertical height h of the application position P at which ink discharged from the head <NUM> is applied on the application surface 100a. The table <NUM> is a table indicating a relation between a predetermined height h and a predetermined ink amount m. The ink amount determination unit <NUM> outputs information of the ink amount m for each application position P to the discharge control unit <NUM>.

The discharge control unit <NUM> causes the head <NUM> to discharge the ink amount m of the ink <NUM>, determined by the ink amount determination unit <NUM>. The discharge control unit <NUM> temporarily stores information of the ink amount m for each application position P input from the ink amount determination unit <NUM> in the RAM <NUM> and controls the ink amount m to be discharged from the head <NUM> according to the application position P that changes the position due to the relative movement of the head <NUM> by the mover <NUM>.

In the case of the continuous discharge type, the discharge control unit <NUM> controls the time during which the head <NUM> discharges the ink <NUM>, the discharge speed at which the head <NUM> discharges the ink <NUM>, or the opening area of the nozzle of the head <NUM> so that the discharge control unit <NUM> can control the ink amount m discharged from the head <NUM>. In the case of the droplet discharge type, the discharge control unit <NUM> controls the volume of ink droplets formed from the ink <NUM> or the pressure applied to ink in the head <NUM>, thus allowing control of the ink amount m discharged from the head <NUM>. The discharge control unit <NUM> can increase the volume of the ink droplet, for example, by combining a plurality of ink droplets.

The movement control unit <NUM> controls the relative movement by the mover <NUM>. In the present embodiment, the movement control unit <NUM> controls the X-direction driver <NUM>, the Y-direction driver <NUM>, and the Z-direction driver <NUM> to control the relative movement by the mover <NUM>. In the present embodiment, the movement control unit <NUM> controls the discharge of the ink <NUM> by the head <NUM> and the relative movement by the mover <NUM> so that the ink <NUM> discharged from the head <NUM> by a plurality of relative movements by the mover <NUM> is applied to the application surface 100a.

<FIG> is a flowchart of an operation of the liquid discharge apparatus <NUM>. <FIG> illustrates an operation of an ink application to the application surface 100a by the liquid discharge apparatus <NUM>. The liquid discharge apparatus <NUM> starts the operation illustrated in <FIG>, for example, when the liquid discharge apparatus <NUM> receives an instruction of the ink application, input by a user through the operation panel <NUM>.

First, in step S81, the acquisition unit <NUM> of the liquid discharge apparatus <NUM> inputs the shape information Sd from the external apparatus such as the host PC and acquires the shape information Sd.

Subsequently, in step S82, the ink amount determination unit <NUM> of the liquid discharge apparatus <NUM> determines the ink amount m to be discharged from the head <NUM> based on the shape information Sd input from the acquisition unit <NUM>. The ink amount determination unit <NUM> outputs information of the determined ink amount m to the discharge control unit <NUM>.

Subsequently, in step S83, the movement control unit <NUM> of the liquid discharge apparatus <NUM> controls the relative movement between the head <NUM> and the application surface 100a by the mover <NUM>. The discharge control unit <NUM> of the liquid discharge apparatus <NUM> controls the discharge of the ink <NUM> from the head <NUM> to apply the ink <NUM> to the application surface 100a.

Subsequently, in step S84, the controller <NUM> of the liquid discharge apparatus <NUM> determines whether the operation of the ink application to the application surface 100a is to be ended. The controller <NUM> can determine whether the operation of the ink application to the application surface 100a is to be ended based on, for example, data input by a user using the operation panel <NUM> or image data.

In step S84, when the controller <NUM> determines that the operation of the ink application to the application surface 100a is to be ended (YES in step S84), the liquid discharge apparatus <NUM> ends the operation of the ink application. In step S84, when the controller <NUM> determines that the operation of the ink application to the application surface 100a is not to be ended (NO in step S84), the liquid discharge apparatus <NUM> processes the operations of step S83 and step <NUM> again.

Due to the above-described processing, the liquid discharge apparatus <NUM> can apply the ink <NUM> to the application surface 100a. In the present embodiment, the operation in which the ink amount determination unit <NUM> determines the ink amount m for each application position P in the overall application surface 100a in advance before the ink <NUM> is applied to the application surface 100a in step S83 has been described as an example. However, embodiments of the present disclosure are not limited to such a configuration. The ink amount determination unit <NUM> of the liquid discharge apparatus <NUM> may determine the ink amount m each time the application position P on the application surface 100a changes the position due to the relative movement of the head <NUM> and output the ink amount m to the discharge control unit <NUM>.

The operation of the liquid discharge apparatus <NUM> according to an embodiment of the present disclosure is described with reference to <FIG>.

<FIG> are diagrams illustrating ink application according to a control sample. <FIG> is a diagram illustrating ink discharge. <FIG> is a diagram illustrating ink immediately after the ink is applied to an application surface by the ink discharge illustrated in <FIG>. <FIG> is a diagram illustrating a state after the ink has dripped as time elapses from the state illustrated in <FIG>.

The ink dripping means that ink applied to an application surface drips from a high position to a low position on the application surface due to the action of gravity.

<FIG> are diagrams illustrating ink application according to the present embodiment. <FIG> is a diagram illustrating an example of ink discharge. <FIG> is a diagram illustrating ink immediately after the ink is applied to an application surface by the ink discharge of <FIG>. <FIG> is a diagram illustrating a state after the ink has dripped as time elapses from the state of <FIG>.

As illustrated in <FIG>, a head 300X according to the control sample discharges ink 325X to an application surface 100aX. In <FIG>, the head 300X discharges three ink droplets formed with the ink 325X. In the control sample, the volumes of the three ink droplets are substantially equal.

As illustrated in <FIG>, the ink 325X discharged from the head 300X forms an ink film 326X on the application surface 100aX immediately after the ink 325X is applied to the application surface 100aX. Since the ink 325X is not dried and has fluidity immediately after the ink 325X is applied to the application surface 100aX, the ink dripping occurs due to the action of gravity, and the ink 325X moves from a high position to a low position on the application surface 100aX. As drying progresses with a lapse of time, the amount of movement of the ink 325X from the high position to the low position on the application surface 100aX becomes smaller, and eventually stops and adheres to the application surface 100aX.

When the ink 325X in the ink film 326X drips downward (-Y-direction side) as illustrated in <FIG>, an ink film 327X having a film thickness that increases toward the lower side is formed on the application surface 100aX.

As described above, in the control sample, the thickness of the ink film 327X formed on the application surface 100a is non-uniform.

In the present embodiment, as illustrated in <FIG>, the liquid discharge apparatus <NUM> increases the ink amount m of the ink <NUM> to be discharged from the head <NUM> as the height of the application position P in the vertical direction on the application surface 100a is higher. Application positions P1, P2, and P3 represent three application positions P having different heights in the vertical direction.

The application position P1 is a position at a height h1 from a reference height, the application position P2 is a position at a height h2 from the reference height, and the application position P3 is a position at a height h3 from the reference height. The reference height may be determined at any height, for example, the reference height may be the height of the ground on which the liquid discharge apparatus <NUM> is installed. The height h1 is higher than each of the height h2 and height h3, and the height h2 is higher than the height h3. In other words, the height h1, the height h2, and the height h3 have a relation of "h1 > h2 > h3".

The head <NUM> discharges and applies a large droplet 325a, which is an ink droplet formed with the ink <NUM>, to the application position P1 of the application surface 100a. In addition, the head <NUM> discharges and applies a medium droplet 325b, which is an ink droplet formed with the ink <NUM> and has a smaller volume than the large droplet 325a, to the application position P2 of the application surface 100a. Further, the head <NUM> discharges and applies a small droplet 325c, which is an ink droplet formed with the ink <NUM> and has a smaller volume than the medium droplet 325b, to the application position P3 of the application surface 100a. The ink amount increases as the volume of ink droplet increases.

As illustrated in <FIG>, the ink <NUM> discharged from the head <NUM> forms an ink film <NUM> on the application surface 100a immediately after the ink <NUM> is applied to the application surface 100a. The ink film <NUM> is the thickest at the application position P1 and becomes thinner in the order of the application position P2 and the application position P3 in accordance with the volumes of the ink droplets applied to the application positions P1, P2, and P3. In other words, immediately after the ink <NUM> is applied to the application surface 100a, the ink film <NUM> has a non-uniform thickness that is thicker toward the upper side (+Y-direction side).

When the ink dripping occurs due to the fluidity of the ink <NUM> from the state of the ink film <NUM>, a part of the ink <NUM> applied to the application position P1 flows to the lower side. As a result, as illustrated in <FIG>, the ink amount at each application position P along the vertical direction is substantially equalized, and then an ink film <NUM> having a substantially uniform film thickness is obtained.

As described above, the liquid discharge apparatus <NUM> according to the present embodiment applies the ink <NUM> to the application surface 100a. The liquid discharge apparatus <NUM> includes the head <NUM> that discharges and applies the ink <NUM> to the application surface 100a and the controller <NUM> that is configured to control discharge of the ink <NUM> by the head <NUM> based on the vertical height h of an application position P at which the ink <NUM> is applied on the application surface 100a.

For example, the controller <NUM> controls the ink amount m of the ink <NUM> discharged from the head <NUM> to increase the ink amount m as the height h of the application position P is higher.

Immediately after the ink <NUM> is applied to the application surface 100a, the ink film <NUM> formed on the application surface 100a with the ink <NUM> discharged from the head <NUM> has a larger thickness as the height h of the application position P is higher. However, the ink <NUM> having fluidity flows from an upper portion having a large film thickness to a lower portion having a small film thickness due to ink dripping by the action of gravity. As a result, the ink amount at each application position P along the vertical direction is substantially equalized, and thus the ink film <NUM> having a substantially uniform film thickness is obtained. Due to the above-described configuration, in the present embodiment, the liquid discharge apparatus <NUM> which is excellent in the application qualities of the ink <NUM> to the application surface 100a can be provided.

In the present embodiment, an example in which the ink amount m is changed by changing the volume of the ink droplet has been described. However, embodiments of the present invention are not limited to this example. In the case of the continuous discharge type, the ink amount m may be changed by changing a time or a speed at which the ink <NUM> is discharged from the head <NUM> or a cross-sectional area of a nozzle disposed in the head <NUM>. In the case of the droplet discharge type, the ink amount m may be changed by changing a discharge frequency of the ink <NUM> by the head <NUM> or a pressure applied to the ink <NUM> in the head <NUM> for discharge.

In the present embodiment, the liquid discharge apparatus <NUM> includes the mover <NUM> that relatively moves the application surface 100a and the head <NUM> at least along the X-direction (predetermined direction). The controller <NUM> controls the discharge of the ink <NUM> by the head <NUM> and the relative movement by the mover <NUM> so that the ink <NUM> discharged from the head <NUM> is applied to the application surface 100a by a plurality of relative movements by the mover <NUM>. Accordingly, the liquid discharge apparatus <NUM> can move the head <NUM> in a wide range of the application surface 100a by the mover <NUM> and apply the ink <NUM>. In addition, the liquid discharge apparatus <NUM> can relatively move the application surface 100a and the head <NUM> also in the Y-direction by the mover <NUM> to apply the ink <NUM> to a wider range of the application surface 100a. Further, the liquid discharge apparatus <NUM> can relatively move the application surface 100a and the head <NUM> also in the Z-direction to apply the ink <NUM> to a desired position on the application surface 100a even when the application surface 100a is a three-dimensional curved surface.

In addition, in the present embodiment, the liquid discharge apparatus <NUM> includes the acquisition unit <NUM> that acquires the shape information Sd of the application surface 100a, and the controller <NUM> controls the discharge of the ink <NUM> by the head <NUM> based on the shape information Sd of the application surface 100a acquired by the acquisition unit <NUM>. Accordingly, even when the application surface 100a is a surface having a three-dimensional shape such as a surface of a vehicle body, the liquid discharge apparatus <NUM> can apply the ink amount m of the ink <NUM> corresponding to the height h.

Next, a liquid discharge apparatus 1000a according to a second embodiment is described. Note that the same components as the components described in the first embodiment are denoted by the same reference numerals, and redundant description is omitted as appropriate. The same applies to embodiments and modifications described below.

In the present embodiment, a controller 500a included in the liquid discharge apparatus 1000a controls an ink amount m of ink <NUM> discharged from the head <NUM> based on a height h of an application position P along the vertical direction and an inclination θ of an application surface 100b with respect to the horizontal direction at the application position P.

<FIG> is a diagram illustrating an example of the functional configuration of the controller 500a according to the second embodiment of the present invention. The controller 500a includes an ink amount determination unit 52a.

The ink amount determination unit 52a determines the ink amount m to be discharged from the head <NUM> based on the shape information Sd input from the acquisition unit <NUM>. In the present embodiment, the ink amount determination unit 52a increases the ink amount m of the ink <NUM> discharged from the head <NUM> as the height h of the application position P is higher. In addition, the ink amount determination unit 52a determines the ink amount m so that the change in the ink amount corresponding to the predetermined height difference m is large as the inclination θ of the application surface 100b at the application position P is larger.

For example, the ink amount determination unit 52a calculates based on the shape information Sd to acquire the vertical height h of the application position P at which the ink <NUM> discharged from the head <NUM> is applied on the application surface 100b and the inclination θ of the application surface 100b with respect to the horizontal direction at the application position P. The ink amount determination unit 52a refers to a table 520a stored in the storage device <NUM> based on the acquired height h and inclination θ, and determines the ink amount m. The table 520a is a table indicating the relation between the predetermined height h, inclination θ, and the ink amount m. The ink amount determination unit 52a can output information of the ink amount m for each application position P to the discharge control unit <NUM>.

<FIG> is a diagram illustrating an example of a relation between the height h and the ink amount m in a case where the inclination θ of the application surface 100b is relatively small. <FIG> is a diagram illustrating an example of a relation between the height h and the ink amount m when the inclination θ of the application surface 100b is relatively large.

In <FIG>, the horizontal axis represents the height h, and the vertical axis represents the ink amount m. The height difference Δ h is a height difference per unit length and is an example of the predetermined height difference. The unit length of the height difference is, for example, one millimeter.

As illustrated in <FIG>, in a case where the inclination θ of the application surface 100b is relatively small, a change in the ink amount m corresponding to the height difference Δh is Δm1. On the other hand, as illustrated in <FIG>, in a case where the inclination θ of the application surface 100b is relatively large, a change in the ink amount m corresponding to the height difference Δh is Δm2. The change Δm2 is greater than the change Δm1.

As described above, the ink amount determination unit 52a can determine the ink amount m so that the change Δm in the ink amount m corresponding to the height difference Δh increases as the inclination θ of the application surface 100b at the application position P increases.

The operation of the liquid discharge apparatus 1000a is described with reference to <FIG>. <FIG> is a diagram illustrating an example of discharge of the ink <NUM> by the liquid discharge apparatus 1000a. <FIG> is a diagram illustrating an example of the ink <NUM> applied to the application surface 100b by the discharge illustrated in <FIG>. <FIG> is a side view of the state illustrated in <FIG>. <FIG> is a diagram illustrating an example of a state after the ink dripping as time elapses from the state illustrated in <FIG>.

As illustrated in <FIG>, application positions P4, P5, and P6 represent positions on the application surface 100b to which the ink <NUM> is applied. The application position P4 is a position at a height h4 from the reference height. The application position P5 is a position at a height h5 from the reference height. The application position P6 is a position at a height h6 from the reference height. The height h4 is higher than each of the height h5 and the height h6, and the height h5 is higher than the height h6. In other words, the relation among the heights h4, h5, and h6 is "h4 > h5 > h6".

The inclination θ illustrated in <FIG> indicates an inclination of the application surface 100b at the application position P5 with respect to the horizontal direction (Z-direction). The application surface 100b is a surface having a curvature in at least one direction. In the present embodiment, the application surface 100b is a surface having a curvature in the Y-direction. The inclination with respect to the horizontal direction at the application position P4 is smaller than the inclination θ at the application position P5, and the inclination with respect to the horizontal direction at the application position P6 is larger than the inclination θ at the application position P5.

For example, the liquid discharge apparatus 1000a sets the ink amount m at the application position P4 to be larger than the ink amount m at the application position P6. In addition, the liquid discharge apparatus 1000a sets the change Δm in the ink amount m corresponding to the height difference Δh at the application position P6 to be larger than the change Δm in the ink amount m corresponding to the height difference Δh at the application position P4.

In the example illustrated in <FIG>, the liquid discharge apparatus 1000a discharges a large droplet 325a, which is a droplet of the ink <NUM> and has a relatively large volume, from the head <NUM> to apply the large droplet 325a to the application position P4 on the application surface 100b. In addition, the liquid discharge apparatus 1000a discharges a medium droplet 325b having a smaller volume than the large droplet 325a from the head <NUM> to apply the medium droplet 325b to the application position P5 on the application surface 100b. Further, the liquid discharge apparatus 1000a discharges a small droplet 325c having a smaller volume than the medium droplet 325b from the head <NUM> to apply the small droplet 325c to the application position P6 on the application surface 100b. However, since the inclination at the application position P4 is smaller than the inclination at the application position P6, the difference between the ink amount m at the application position P4 and the ink amount m at the application position P6 is smaller than the difference of the ink amount m based on the difference between the height h4 and the height h6.

As illustrated in <FIG>, the ink <NUM> is applied to form a first region <NUM> and a second region <NUM> on the application surface 100b. Large droplets 325a are applied to form the first region <NUM> on the application surface 100b, and small droplets 325c are applied to form the second region <NUM> on the application surface 100b. The first region <NUM> is located at a position higher than the second region <NUM> in the vertical direction.

Since the ink <NUM> has fluidity immediately after the ink <NUM> is applied to the application surface 100b, the ink <NUM> drips due to the action of gravity and moves from a high position to a low position on the application surface 100b. Then, as drying progresses with the lapse of time, the amount of movement of the ink <NUM> becomes smaller, and the ink <NUM> eventually stops and adheres to the application surface 100b.

Since the large droplets 325a are applied to the first region <NUM>, the amount m of ink dripping is relatively large. Since the small droplets 325c are applied to the second region <NUM>, the amount m of ink dripping is relatively small.

As illustrated in <FIG>, the ink <NUM> discharged from the head <NUM> forms an ink film <NUM> on the application surface 100a immediately after the ink <NUM> is applied to the application surface 100b. In accordance with the volumes of the ink droplets applied to the application positions P4, P5, and P6, the ink film <NUM> has a non-uniform thickness in which the thickness increases toward the upper side. For example, the ink film <NUM> has a larger thickness in an upper region 326a of the ink film <NUM>.

When ink dripping occurs due to the fluidity of the ink <NUM> from the state of the ink film <NUM> as illustrated in <FIG>, a part of the ink <NUM> flows to the lower side. As a result, as illustrated in <FIG>, the ink amount at each application position P on the application surface 100b is substantially equalized, and then an ink film <NUM> having a substantially uniform film thickness is obtained.

As described above, the controller 500a included in the liquid discharge apparatus 1000a according to the present embodiment controls the ink amount m of the ink <NUM> to be discharged from the head <NUM> based on the height h of the application position P along the vertical direction and the inclination θ of the application surface 100b with respect to the horizontal direction at the application position P.

For example, the controller 500a increases the ink amount m applied to the application surface 100b as the height h of the application position P in the vertical direction is higher. In addition, the controller 500a controls so that the change Δm of the ink amount m corresponding to the height difference Δh (predetermined height difference) increases as the inclination θ of the application surface 100b at the application position P increases.

Immediately after the ink <NUM> is applied to the application surface 100b, the ink film <NUM> formed on the application surface 100b by the ink <NUM> discharged from the head <NUM> has a larger thickness as the height h of the application position P is higher. However, the ink <NUM> having fluidity flows from an upper portion having a large film thickness to a lower portion having a small film thickness due to ink dripping by the action of gravity. As a result, the amount of ink at each application position P along the vertical direction is substantially equalized, and thus the ink film <NUM> having a substantially uniform film thickness is obtained. Due to the above-described configuration, in the present embodiment, the liquid discharge apparatus 1000a excellent in the application qualities of the ink <NUM> to the application surface 100b can be provided.

In the present embodiment, the application surface 100b is a surface having a curvature in at least one direction. The liquid discharge apparatus 1000a can also obtain the application qualities of the ink <NUM> to the application surface 100b in the case of the application surface 100b as described above.

Note that the effects other than described above in the liquid discharge apparatus 1000a are the same as the effects of the liquid discharge apparatus <NUM> according to the first embodiment.

In the present embodiment, a curved surface having a curvature in at least one direction have been exemplified as the application surface 100b. In some embodiments, however, the application surface 100b may be a flat and inclined surface. <FIG> is a diagram illustrating an example of discharge of the ink <NUM> in a case where the application surface 100b is a flat and inclined surface.

As illustrated in <FIG>, the application surface 100b is a flat and inclined surface inclined by an inclination θ with respect to the Z-direction (horizontally). The liquid discharge apparatus 1000a causes the controller 500a to control the ink amount m of the ink <NUM> to be discharged from the head <NUM> based on the height h of the application position P along the vertical direction and the inclination θ of the application surface 100b with respect to the horizontal direction at the application position P. Accordingly, the same operation effect of the liquid discharge apparatus 1000a described above can be obtained.

Next, a liquid discharge apparatus 1000b according to a third embodiment is described.

In the present embodiment, a controller 500b included in the liquid discharge apparatus 1000b controls an interval d between adjacent liquids such as adjacent inks <NUM> discharged from the head <NUM> and applied to the application surface 100b.

<FIG> is a diagram illustrating an example of the functional configuration of the controller 500b. The controller 500b includes an interval determination unit <NUM>.

The interval determination unit <NUM> determines the interval d between the adjacent inks <NUM> which are discharged from the head <NUM> and are applied to the application surface 100b, based on the shape information Sd input from the acquisition unit <NUM>. In the present embodiment, the interval determination unit <NUM> sets the interval d between the adjacent inks <NUM> applied to the application surface 100b to be narrower as the height h of the application position P along the vertical direction is higher. In addition, as the inclination θ of the application surface 100b at the application position P increases, the interval determination unit <NUM> determines the interval d so that the change Δd corresponding to the predetermined height difference of the interval d between the adjacent inks <NUM> applied to the application surface 100b increases.

For example, the interval determination unit <NUM> calculates, based on the shape information Sd, the vertical height h of the application position P at which the ink <NUM> discharged from the head <NUM> is applied on the application surface 100b and the inclination θ of the application surface 100b with respect to the horizontal direction at the application position P, to acquire the height h and the inclination θ. The interval determination unit <NUM> refers to a table 520b stored in the storage device <NUM> based on the acquired height h and inclination θ and determines the interval d. The table 520b is a table indicating the relation between the predetermined height h, the inclination θ, and the interval d. The interval determination unit <NUM> can output information of the interval d for each application position P to the discharge control unit <NUM>.

The operation of the liquid discharge apparatus 1000b is described with reference to <FIG> is a diagram illustrating an example of the ink discharge by the liquid discharge apparatus 1000b. <FIG> is a diagram illustrating an example of the ink <NUM> applied to the application surface 100b by the ink discharge illustrated in <FIG>.

The height h4 of the application position P4 is higher than the height h6 of the application position P6. The inclination θ of the application surface 100b at the application position P6 is larger than the inclination θ of the application surface 100b at the application position P4.

The liquid discharge apparatus 1000b sets an interval d4 between the adjacent inks <NUM> applied to the application surface 100b at the application position P4 to be narrower than an interval d6 between the adjacent inks <NUM> applied to the application surface 100b at the application position P6. The liquid discharge apparatus 1000b controls so that the change Δd corresponding to the height difference Δ h of the interval d between the adjacent inks <NUM> applied to the application surface 100b is larger as the inclination θ of the application surface 100b at the application position P is larger.

In the example illustrated in <FIG>, the interval d between the adjacent inks <NUM> in the application position P4 is indicated by the interval d4. The interval d between the adjacent inks <NUM> in the application position P6 is indicate by the interval d6. The interval d4 is narrower than the interval d6. Since the inclination θ at the application position P4 is smaller than the inclination θ at the application position P6, the difference between the interval d4 at the application position P4 and the interval d6 at the application position P6 is smaller than the difference of the interval d based on the difference between the height h4 and the height h6.

As illustrated in <FIG>, the ink <NUM> is applied to form a third region <NUM> and a fourth region <NUM> on the application surface 100b. The third region <NUM> is located at a position higher than the fourth region <NUM> in the vertical direction. Comparing the interval d between the adjacent inks <NUM>, the interval d4 in the third region <NUM> is narrower than the interval d6 in the fourth region <NUM>. Note that the volumes of ink droplets applied to the third region <NUM> and the fourth region <NUM> are substantially equal.

Since the ink <NUM> has fluidity after the ink <NUM> is applied to the application surface 100b, the ink <NUM> drips due to the action of gravity and moves from a high position to a low position on the application surface 100b. Then, as drying progresses with the lapse of time, the amount of movement of the ink <NUM> becomes smaller, and the ink <NUM> eventually stops and adheres to the application surface 100b.

Since the ink amount m increases as the interval d between the inks <NUM> on the application surface 100b decreases, the ink amount m in the third region <NUM> becomes larger than the ink amount m in the fourth region <NUM>.

When ink dripping occurs due to the fluidity of the ink <NUM> from the state illustrated in <FIG>, a part of the ink <NUM> applied to each of the third region <NUM> and the fourth region <NUM> flows to the lower side. As a result, the ink amount at each application position P on the application surface 100b is substantially equalized, and thus an ink film having a substantially uniform film thickness is obtained.

As described above, the controller 500b included in the liquid discharge apparatus 1000b according to the present embodiment controls the interval d between the adjacent inks <NUM> which are discharged from the head <NUM> and applied to the application surface 100b.

For example, the controller 500b sets the interval d between the adjacent inks <NUM> applied to the application surface 100b to be narrower as the height h of the application position P along the vertical direction is higher. In addition, the controller 500b controls so that the change Δd corresponding to the height difference Δh of the interval d between the adjacent inks <NUM> applied to the application surface 100b increases as the inclination θ of the application surface 100b at the application position P is larger.

Immediately after the ink <NUM> is applied to the application surface 100b, the ink film formed on the application surface 100b with the ink <NUM> discharged from the head <NUM> has a larger thickness as the height h of the application position P is higher. However, the ink <NUM> having fluidity flows from an upper portion having a large film thickness to a lower portion having a small film thickness due to ink dripping by the action of gravity. As a result, the ink amount at each application position P along the vertical direction is substantially equalized, and thus an ink film having a substantially uniform film thickness is obtained. Due to the above-described configuration, in the present embodiment, the liquid discharge apparatus 1000b which is excellent in the application qualities of the ink <NUM> to the application surface 100b can be provided.

Note that, according to an example not covered by the appended claims, the liquid discharge apparatus 1000b may control the interval d based on only the height h of the application position P. In addition, according another example not covered by the appended claims, the liquid discharge apparatus 1000b may control the ink amount m and the interval d based on only the height h of the application position P. Further, the liquid discharge apparatus 1000b may control the ink amount m and the interval d based on the height h of the application position P and the inclination θ of the application surface 100b at the application position P. Note that the effects other than described above in the liquid discharge apparatus 1000b are the same as the effects of the liquid discharge apparatus <NUM> according to the first embodiment.

The liquid discharge apparatus <NUM>, the liquid discharge apparatus 1000a, or the liquid discharge apparatus 1000b can be applied to various uses. <FIG> is a diagram illustrating an example of application of the liquid discharge apparatus <NUM> to a painting robot <NUM>. The painting robot <NUM> paints a vehicle body (body) of an automobile.

The painting robot <NUM> includes a robot arm <NUM> that can freely move like human arms by a plurality of joints and includes a head <NUM> that discharges ink from a leading end of the robot arm <NUM>. The robot arm <NUM> includes a three-dimensional (3D) sensor <NUM> disposed close to the head <NUM>.

As the painting robot <NUM>, an articulated robot can be used that has an appropriate number of axes such as five axes, six axes, or seven axes. The painting robot <NUM> detects a position of the head <NUM> with respect an object <NUM> (vehicle body in the present embodiment) by the 3D sensor <NUM> and moves the robot arm <NUM> based on the result of the detection to paint the object <NUM>. In this case, the head <NUM> according to the embodiments of the present invention can be used as the head <NUM>.

Although the embodiments have been described above, embodiments of the present invention are not limited to the above embodiments. In other words, various modifications and improvements can be made within the scope of the appended claims.

In the embodiments of the present invention, for example, a liquid to be discharged from the head <NUM> may include 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 deoxyribonucleic acid (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 object <NUM> having the application surface 100a is a material to which liquid is attached and firmly adheres or an object to which liquid is attached and penetrates. Specific examples of the material include, but are not limited to, a recording medium such as a vehicle body, building material, a sheet, recording sheet, 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 includes any material to which liquid is adhered, unless particularly limited.

The embodiments of the present invention also include a liquid discharge method according to appended claim <NUM>, which method can achieve operational effects equivalent to those of the above-described liquid discharge apparatus.

The embodiments of the present invention also include a carrier medium storing computer-readable program code according to appended claim <NUM>, which can provide effects equivalent to those of the above-described liquid discharge apparatus.

Claim 1:
A liquid discharge apparatus (<NUM>) comprising:
a head (<NUM>) configured to discharge liquid to apply the liquid to an application surface; and
a controller (<NUM>) configured to control discharge of the liquid from the head (<NUM>) based on a vertical height of an application position at which the liquid is applied on the application surface,
wherein
the controller (<NUM>) is configured to control an amount of the liquid discharged from the head (<NUM>),
increase the amount of the liquid to be discharged from the head (<NUM>) as the vertical height of the application position on the application surface is higher, and
characterized in that the controller (<NUM>) is furthermore configured to
control the amount of the liquid in a manner such that a change in the amount of the liquid corresponding to a predetermined height difference is larger as an inclination of the application surface at the application position is larger.