JP2011020016A - Liquid discharge apparatus and head maintenance apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid discharge apparatus providing a state that a cleaning liquid is spread over all the parts with which a functional liquid in a head can be brought into contact while suppressing an increase in the scale of the surroundings of a head cap of a suction unit. <P>SOLUTION: The liquid discharge apparatus includes: a liquid discharge head having a nozzle substrate where a discharge nozzle discharging the liquid is formed; the head cap for sealing a nozzle forming surface on which the discharge nozzle of a liquid discharge head is formed; a suction means communicating with the head cap and for sucking a gas or the liquid in the head cap; a cleaning liquid supply meas for supplying the cleaning liquid into the head cap; and a liquid level detection means for detecting the liquid surface of the liquid in the head cap. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid material discharge device including a discharge head having a discharge nozzle for discharging a liquid material, and a head maintenance device for performing maintenance of the discharge head.

2. Description of the Related Art Conventionally, a discharge head having a discharge nozzle for discharging a liquid material is provided, and the liquid material is disposed at an arbitrary position on the drawing target by discharging the liquid and landing on an arbitrary position on the drawing target. A liquid material discharge apparatus is known. By using such a liquid material discharge device, it is possible to accurately apply a liquid material containing a functional film material such as a color filter film of a color liquid crystal device to an arbitrary position in an arbitrary amount. . In particular, a droplet discharge head that discharges a liquid as droplets has a precise planar shape and film thickness because it can selectively discharge minute droplets from the discharge nozzle and land with high positional accuracy. A film can be formed.
In recent years, for example, a dispersed metal ink (metal wiring ink) in which metal fine particles such as silver (Ag) are dispersed in a solvent is used to form a wiring pattern on a substrate. By forming a wiring pattern using a droplet discharge head, a fine wiring pattern or a wiring pattern with a narrow pitch can be efficiently and accurately manufactured.

The liquid droplet ejection head is supplied with a liquid material from a separate tank or the like, and temporarily stores the supplied liquid material in an ink chamber (cavity) provided therein. Then, the liquid material stored in the ink chamber is discharged as droplets from a large number of discharge nozzles formed on the nozzle plate.
The liquid material is a liquid material that can be suitably discharged from the droplet discharge head and solidifies to form a film having a specific function. When the droplet discharge head is waiting, the liquid material stored in the ink chamber Your body may dry out. When the liquid material is dried, it not only thickens and changes the discharge amount, but also partially solidifies, which may cause clogging of the holes of the discharge nozzle and bending of the flight at the time of discharge. . A head maintenance device such as a head suction device is used to remove the liquid material that has started to dry from the droplet discharge head.
Even in a head maintenance device such as a head suction device, the sucked liquid material may be dried and attached inside the head suction device or the like, so that the function of the head suction device or the like may be impaired and lowered. As an apparatus having means for removing the deposits of the head suction device, Patent Document 1 discloses a suction unit, a droplet discharge device, and an electro-optical device manufacturing method including supply means for supplying a cleaning liquid to the head cap of the suction unit. An electro-optical device and an electronic apparatus are disclosed.
Patent Document 1 also discloses a configuration including a liquid amount detection unit that detects a liquid amount at which the head cap is full. However, the capacity of the head cap is absorbed by the individual caps, the amount of deposits, the amount of residual liquid that could not be discharged when the liquid or cleaning liquid was discharged, and the absorbent material installed in the cap. There are many fluctuation factors such as the amount of liquid, the solute of the liquid, and the amount of cleaning liquid, and it is not constant. For this reason, even if the amount of liquid is adjusted appropriately, it is not always possible to achieve a state in which the cleaning liquid is spread over all portions of the head cap that may be contacted with the functional liquid.
In Patent Document 2, a bottom portion and a side wall that form a space are disposed at a position covering a portion that contacts the discharge head of the suction unit, and a functional liquid is supplied to the entire head cap by supplying a cleaning liquid to the space. A suction device that can perform the above and a droplet discharge device including the same are disclosed.

JP 2008-80209 A JP 2008-142653 A

  However, the apparatus disclosed in Patent Document 2 has a problem that the periphery of the head cap of the suction unit becomes large in order to form the bottom and side walls that form the space. When the periphery of the head cap of the suction unit is increased, the interval at which the head cap, which is a portion in contact with the head, can be arranged is increased. As a result, in an apparatus including a plurality of ejection heads, the arrangement interval of the head caps corresponding to the arrangement interval of the ejection heads cannot always be realized. Therefore, depending on the arrangement of the ejection heads, the apparatus disclosed in Patent Document 2 There was a problem that was not necessarily applicable.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A liquid material discharge apparatus according to this application example seals a liquid material discharge head including a discharge nozzle for discharging a liquid material, and a nozzle forming surface on which the discharge nozzles of the liquid material discharge head are formed. A head cap that communicates with the head cap and sucks a gas or liquid in the head cap; a cleaning liquid supply unit that communicates with the head cap and supplies a cleaning liquid into the head cap; and the head Liquid level detecting means for detecting the liquid level of the liquid in the cap.

  According to the liquid material discharge apparatus according to this application example, the cleaning liquid can be supplied into the head cap by the cleaning liquid supply unit, and the cleaning liquid in the head cap can be sucked and discharged by the suction unit. Thereby, the inside of the head cap can be cleaned with the cleaning liquid. By providing the liquid level detection means, when supplying the cleaning liquid into the head cap by the cleaning liquid supply means, the cleaning liquid is detected up to an appropriate position in the head cap by detecting the liquid level of the cleaning liquid using the liquid level detection means. Can be met.

  Application Example 2 In the liquid material discharge device according to the application example, the liquid level detection unit is disposed at a position where it can be detected that the liquid level has reached the edge height of the head cap. Is preferred.

  According to this liquid material discharge device, when the cleaning liquid is supplied into the head cap by the cleaning liquid supply means, the cleaning liquid reaches the height of the edge of the head cap by detecting the liquid level of the cleaning liquid by the liquid level detection means. That is, it can be detected that the inside of the head cap is full. Accordingly, the cleaning liquid can be filled until the inside of the head cap becomes full. At the same time, the supply of the cleaning liquid is stopped when the cleaning liquid becomes full in the head cap, thereby preventing the cleaning liquid from overflowing from the head cap.

  Application Example 3 In the liquid material ejection device according to the application example, the liquid level detection unit can detect a portion where the liquid level of the liquid in the head cap rises from the edge of the head cap due to surface tension. It is preferable that it is arrange | positioned.

According to this liquid material discharge device, when the cleaning liquid is supplied into the head cap by the cleaning liquid supply means, the liquid level of the cleaning liquid in the head cap is detected by detecting the liquid level of the cleaning liquid by the liquid level detection means. By this, it can be detected that the head cap is raised from the edge. In general, when a container with an upper opening is filled with liquid and further liquid is added, the liquid can be kept in a raised state due to surface tension. Maintained.
By detecting the liquid level of the cleaning liquid with the liquid level detecting means, the liquid level of the cleaning liquid in the head cap rises from the edge of the head cap due to surface tension, that is, the cleaning liquid reaches the edge of the inside of the head cap. The cleaning liquid can be filled until it becomes full. At the same time, the supply of the cleaning liquid is stopped when the liquid level of the cleaning liquid is detected by the liquid level detecting means, thereby preventing the cleaning liquid from overflowing from the head cap.

  Application Example 4 In the liquid material ejection device according to the application example, the liquid level detection unit is configured to detect a liquid level at the center of gravity of the shape of the head cap in a plane direction perpendicular to the vertical direction. It is preferable that it is disposed.

  According to this liquid material ejecting apparatus, the liquid level detecting means can detect the liquid level of the cleaning liquid at the center of gravity of the shape of the head cap in the plane direction orthogonal to the vertical direction. When the cleaning liquid is fully filled in the head cap and further supplied with the cleaning liquid, the liquid level at the center of gravity of the shape of the head cap in the plan view shape rises to the highest level. By detecting the liquid level of the cleaning liquid at the center of gravity of the head cap shape, it is possible to detect that the cleaning liquid is full in the head cap at an earlier stage than when detecting the liquid level at other positions. it can.

  Application Example 5 In the liquid material discharge apparatus according to the application example described above, the suction unit includes a suction channel communicating with the head cap, and a suction channel opening / closing unit capable of opening and closing the suction channel. preferable.

  According to this liquid material discharge device, the suction flow path communicating with the head cap can be opened and closed by the suction path opening / closing means. By opening the suction channel, the cleaning liquid in the head cap can be sucked and discharged through the suction channel. By closing the suction channel, it is possible to substantially stop the cleaning liquid supplied into the head cap from flowing out of the suction channel.

  Application Example 6 In the liquid material discharge apparatus according to the application example, the cleaning liquid supply unit includes a supply channel communicating with the head cap and a supply channel opening / closing unit capable of opening and closing the supply channel. Is preferred.

  According to this liquid material discharge apparatus, the supply flow path communicating with the head cap can be opened and closed by the supply path opening / closing means. By opening the supply channel, the cleaning liquid can be supplied into the head cap through the supply channel. By closing the supply flow path, the supply of the cleaning liquid to the head cap can be stopped more quickly and reliably than when the supply power source is stopped. Further, it is possible to prevent the cleaning liquid in the head cap from flowing back to the cleaning liquid supply means.

  Application Example 7 In the liquid material discharge apparatus according to the application example, the cleaning liquid supply unit includes a cleaning liquid tank that stores the cleaning liquid, and the liquid level of the cleaning liquid in the cleaning liquid tank is set to a liquid level in the head cap. It is preferable to supply the cleaning liquid to the head cap by making it relatively higher in the vertical direction.

  According to this liquid discharge device, the cleaning liquid can be sent from the cleaning liquid tank to the head cap by the pressure due to the difference between the liquid level of the cleaning liquid in the cleaning liquid tank and the liquid level in the head cap. When the cleaning liquid is supplied from the cleaning liquid tank to the head cap, the difference between the liquid level of the cleaning liquid in the cleaning liquid tank and the liquid level in the head cap is reduced, so that the supply amount per unit time is reduced. In general, when the supply amount per unit time is small, it is easy to detect a state where the liquid level in the head cap becomes a predetermined liquid level and stop the supply of the cleaning liquid in this state. By adjusting the amount of cleaning liquid in the cleaning liquid tank, the supply amount per unit time when the liquid level in the head cap is close to the predetermined liquid level is reduced, and the liquid level in the head cap is set to a predetermined level. The liquid level can be made easy.

  Application Example 8 In the liquid material discharge apparatus according to the application example, it is preferable that the cleaning liquid is a main solvent of a functional liquid discharged from the liquid material discharge head.

  According to this liquid material discharge apparatus, the main solvent of the functional liquid discharged from the liquid material discharge head is supplied to the head cap as the cleaning liquid. The adhering matter on the head cap is mainly due to the functional liquid sucked from the liquid discharge head, and can be easily dissolved by the main solvent of the functional liquid.

  Application Example 9 A head maintenance apparatus according to this application example includes a head cap that seals a nozzle forming surface on which the discharge nozzle is formed of a liquid discharge head including a discharge nozzle that discharges a liquid, and the head cap. A suction means for sucking a gas or a liquid in the head cap, a cleaning liquid supply means for supplying a cleaning liquid into the head cap, and a liquid surface of the liquid in the head cap. And a liquid level detecting means for detecting.

  According to the head maintenance device of this application example, the cleaning liquid can be supplied into the head cap by the cleaning liquid supply means, and the cleaning liquid in the head cap can be sucked and discharged by the suction means. Thereby, the inside of the head cap can be cleaned with the cleaning liquid. By providing the liquid level detection means, when supplying the cleaning liquid into the head cap by the cleaning liquid supply means, the cleaning liquid is detected up to an appropriate position in the head cap by detecting the liquid level of the cleaning liquid using the liquid level detection means. Can be met.

  Application Example 10 In the head maintenance device according to the application example described above, the liquid level detection unit may be disposed at a position where it can be detected that the liquid level has reached the edge height of the head cap. preferable.

  According to this head maintenance device, when the cleaning liquid is supplied into the head cap by the cleaning liquid supplying means, the cleaning liquid reaches the height of the edge of the head cap by detecting the liquid level of the cleaning liquid by the liquid level detecting means. That is, it can be detected that the inside of the head cap is full. Accordingly, the cleaning liquid can be filled until the inside of the head cap becomes full. At the same time, the supply of the cleaning liquid is stopped when the cleaning liquid becomes full in the head cap, thereby preventing the cleaning liquid from overflowing from the head cap.

  Application Example 11 In the head maintenance apparatus according to the application example described above, the liquid level detection unit is configured to detect a portion where the liquid level of the liquid in the head cap rises from the edge of the head cap due to surface tension. It is preferable that it is disposed.

According to this head maintenance device, when the cleaning liquid is supplied into the head cap by the cleaning liquid supply means, the liquid level of the cleaning liquid in the head cap is detected by the surface tension by detecting the liquid level of the cleaning liquid by the liquid level detection means. It can be detected that the head cap has risen from the edge of the head cap. In general, when a container with an upper opening is filled with liquid and further liquid is added, the liquid can be kept in a raised state due to surface tension. Maintained.
By detecting the liquid level of the cleaning liquid with the liquid level detecting means, the liquid level of the cleaning liquid in the head cap rises from the edge of the head cap due to surface tension, that is, the cleaning liquid reaches the edge of the inside of the head cap. The cleaning liquid can be filled until it becomes full. At the same time, the supply of the cleaning liquid is stopped when the liquid level of the cleaning liquid is detected by the liquid level detecting means, thereby preventing the cleaning liquid from overflowing from the head cap.

  Application Example 12 In the head maintenance apparatus according to the application example described above, the liquid level detection unit is arranged at a position where the liquid level of the liquid at the center of gravity of the shape of the head cap in the plane direction orthogonal to the vertical direction can be detected. It is preferable to be provided.

  According to this head maintenance device, the liquid level detecting means can detect the liquid level of the cleaning liquid at the center of gravity of the shape of the head cap in the plane direction orthogonal to the vertical direction. When the cleaning liquid is fully filled in the head cap and further supplied with the cleaning liquid, the liquid level at the center of gravity of the shape of the head cap in the plan view shape rises to the highest level. By detecting the liquid level of the cleaning liquid at the center of gravity of the head cap shape, it is possible to detect that the cleaning liquid is full in the head cap at an earlier stage than when detecting the liquid level at other positions. it can.

  Application Example 13 In the head maintenance apparatus according to the application example described above, it is preferable that the suction unit includes a suction channel communicating with the head cap and a suction channel opening / closing unit capable of opening and closing the suction channel. .

  According to this head maintenance device, the suction flow path communicating with the head cap can be opened and closed by the suction path opening / closing means. By opening the suction channel, the cleaning liquid in the head cap can be sucked and discharged through the suction channel. By closing the suction channel, it is possible to substantially stop the cleaning liquid supplied into the head cap from flowing out of the suction channel.

  Application Example 14 In the head maintenance apparatus according to the application example described above, the cleaning liquid supply unit includes a supply channel communicating with the head cap and a supply channel opening / closing unit capable of opening and closing the supply channel. preferable.

  According to this head maintenance device, the supply flow path communicating with the head cap can be opened and closed by the supply path opening / closing means. By opening the supply channel, the cleaning liquid can be supplied into the head cap through the supply channel. By closing the supply flow path, the supply of the cleaning liquid to the head cap can be stopped more quickly and reliably than when the supply power source is stopped.

  Application Example 15 In the head maintenance apparatus according to the application example described above, the cleaning liquid supply unit includes a cleaning liquid tank that stores the cleaning liquid, and the liquid level of the cleaning liquid in the cleaning liquid tank is higher than the liquid level in the head cap. It is preferable to supply the cleaning liquid to the head cap by making it relatively high in the vertical direction.

  According to this head maintenance device, the cleaning liquid can be sent from the cleaning liquid tank to the head cap by the pressure due to the difference between the liquid level of the cleaning liquid in the cleaning liquid tank and the liquid level in the head cap. When the cleaning liquid is supplied from the cleaning liquid tank to the head cap, the difference between the liquid level of the cleaning liquid in the cleaning liquid tank and the liquid level in the head cap is reduced, so that the supply amount per unit time is reduced. In general, when the supply amount per unit time is small, it is easy to detect a state where the liquid level in the head cap becomes a predetermined liquid level and stop the supply of the cleaning liquid in this state. By adjusting the amount of cleaning liquid in the cleaning liquid tank, the supply amount per unit time when the liquid level in the head cap is close to the predetermined liquid level is reduced, and the liquid level in the head cap is set to a predetermined level. The liquid level can be made easy.

  Application Example 16 In the head maintenance apparatus according to the application example described above, it is preferable that the cleaning liquid is a main solvent of a functional liquid discharged from the liquid discharge head.

  According to this head maintenance device, the main solvent of the functional liquid discharged from the liquid discharge head is supplied to the head cap as the cleaning liquid. The adhering matter on the head cap is mainly due to the functional liquid sucked from the liquid discharge head, and can be easily dissolved by the main solvent of the functional liquid.

FIG. 3 is an external perspective view showing a schematic configuration of a droplet discharge device. (A) is the external appearance perspective view which looked at the droplet discharge head from the nozzle plate side. (B) is a perspective sectional view showing a structure around a pressure chamber of a droplet discharge head. FIG. 6C is a cross-sectional view showing the structure of the discharge nozzle portion of the droplet discharge head. Explanatory drawing which shows the structure of a suction unit. The flowchart which shows the washing | cleaning process which wash | cleans a cap chamber etc. using a washing | cleaning liquid. Explanatory drawing which shows the state which detects the liquid level of the cleaning liquid in a cap chamber by a liquid level sensor. FIG. 2 is a plan view showing a schematic configuration of a head unit. The top view which shows schematic structure of a cap unit. Explanatory drawing which shows the positional relationship of a head cap and a liquid level sensor.

  Hereinafter, an embodiment of a liquid material discharge device and a head maintenance device will be described with reference to the drawings. In the embodiment, a liquid droplet discharge apparatus including a liquid discharge head having a discharge nozzle for discharging liquid droplets as an example of a liquid discharge head having discharge nozzles will be described as an example. In the drawings referred to in the following description, the vertical and horizontal scales of members or portions may be shown differently from actual ones for convenience of illustration.

<Droplet ejection method>
First, the droplet discharge method will be described. Examples of the discharge technique of the droplet discharge method include a charge control method, a pressure vibration method, an electromechanical conversion method, an electrothermal conversion method, and an electrostatic suction method. In the charge control method, a charge is applied to a material with a charging electrode, and the flight direction of the material is controlled with a deflection electrode to be discharged from a discharge nozzle. In addition, the pressure vibration method is a method in which an ultra-high pressure of about 30 kg / cm ² is applied to the material to discharge the material to the tip side of the discharge nozzle. When no control voltage is applied, the material moves straight and the discharge nozzle When a control voltage is applied, electrostatic repulsion occurs between the materials, and the materials are scattered and are not discharged from the discharge nozzle. The electromechanical conversion method utilizes the property that a piezoelectric element (piezoelectric element) is deformed by receiving a pulse-like electric signal. The piezoelectric element is deformed through a flexible substance in a space where material is stored. Pressure is applied, and the material is extruded from this space and discharged from the discharge nozzle.

  In the electrothermal conversion method, a material is rapidly vaporized by a heater provided in a space in which the material is stored to generate bubbles, and the material in the space is discharged by the pressure of the bubbles. In the electrostatic attraction method, a minute pressure is applied to a space in which a material is stored, a meniscus of material is formed on the discharge nozzle, and an electrostatic attractive force is applied in this state before the material is drawn out. In addition to this, techniques such as a system that uses a change in the viscosity of a fluid due to an electric field and a system that uses a discharge spark are also applicable. The droplet discharge method has an advantage that the use of the material is less wasteful and a desired amount of the material can be accurately disposed at a desired position. Among them, the piezo method does not apply heat to the liquid material, so it does not affect the composition of the material, and the droplet size can be easily adjusted by adjusting the drive voltage. Have In the present embodiment, the above-described piezo method is used because the degree of freedom in selecting a liquid material is high and the controllability of droplets is good.

<Droplet ejection device>
Next, the overall configuration of the droplet discharge device will be described with reference to FIG. FIG. 1 is an external perspective view showing a schematic configuration of a droplet discharge device.

As shown in FIG. 1, the droplet discharge device 1 includes a drawing unit 2, a work unit 3, a functional liquid supply unit 4, and a maintenance unit 5.
The drawing unit 2 includes a droplet discharge head 17 (see FIG. 2) that discharges a functional liquid as a liquid as droplets.
The work unit 3 includes a work mounting table 30 on which a work W that is a discharge target of liquid droplets discharged from the liquid droplet discharge head 17 is mounted.
The functional liquid supply unit 4 includes a functional liquid tank, a liquid supply pipe, and a liquid supply tube, and the liquid supply tube is connected to the droplet discharge head 17, and the functional liquid is supplied via the liquid supply tube. Is supplied to the droplet discharge head 17.
The droplet discharge head 17 corresponds to a liquid material discharge head.

  The maintenance unit 5 is capable of moving each device that inspects the discharge state of the droplet discharge head 17, each device such as the suction unit 50 that performs various maintenance of the droplet discharge head 17, and these devices. A supporting moving device is provided. The suction unit 50 includes a cap device 51, a cleaning liquid supply device 71, a drainage device 81, and a liquid level sensor 91 (see FIG. 3). Each device used in a state of facing the droplet discharge head 17 such as the cap device 51 of the suction unit 50 is fixed to the moving plate of the moving device. The moving device moves each of these devices to a position facing the droplet discharge head 17 when the device is used.

The droplet discharge device 1 is also provided with a discharge device control unit 6 that comprehensively controls these units and the like.
The droplet discharge device 1 further includes a plurality of support legs 8 installed on the floor and a surface plate 9 installed on the upper side of the support legs 8. The drawing unit 2, the work unit 3, and the main part of the maintenance unit 5 are disposed on a surface plate 9 having a rectangular shape in plan view. The discharge device controller 6 is accommodated on the lower side of the surface plate 9.

  The work unit 3 is disposed so as to extend in the longitudinal direction of the surface plate 9 (this direction is expressed as “X-axis direction”). A drawing unit 2 is disposed above the work unit 3. The drawing unit 2 extends in a direction orthogonal to the work unit 3 (this direction is expressed as “Y-axis direction”). The drawing unit 2 is supported by two support columns fixed to the surface plate 9 and intersects the work unit 3 above the work unit 3. A functional liquid tank of the functional liquid supply unit 4 and the like are disposed beside the surface plate 9. A maintenance unit 5 is arranged alongside the work unit 3 in the vicinity of one support column of the drawing unit 2.

The drawing unit 2 includes a head unit 21 having a droplet discharge head 17, a head carriage 25 having a head unit 21, and a moving frame 22 on which the head carriage 25 is suspended. By moving the moving frame 22 in the Y-axis direction by the Y-axis scanning mechanism, the droplet discharge head 17 is freely moved in the Y-axis direction. Moreover, it holds at the moved position.
The workpiece unit 3 moves the workpiece mounting table 30 freely in the X-axis direction by moving the workpiece mounting table 30 in the X-axis direction by the X-axis scanning mechanism. Moreover, it holds at the moved position.

  When carrying out drawing, the droplet discharge head 17 provided in the drawing unit 2 moves to the discharge position in the Y-axis direction and stops, and synchronizes with the movement in the X-axis direction of the workpiece W located below, so that the functional liquid Are discharged as droplets. By controlling the workpiece W moving in the X-axis direction and the droplet discharge head 17 moving in the Y-axis direction relatively, the droplets are landed at an arbitrary position on the workpiece W, so that a desired plane is obtained. It is possible to perform shape drawing.

  When the maintenance of the droplet discharge head 17 is performed, the droplet discharge head 17 included in the drawing unit 2 moves to a position facing the maintenance unit 5 in the Y-axis direction and stops. Any device of the maintenance unit 5 moves to a position facing the droplet discharge head 17 at the position, and maintenance work is performed. For example, the cap device 51 of the suction unit 50 is moved by the moving device and is positioned at a position facing the droplet discharge head 17. The head carriage 25 or the cap device 51 is moved up and down by the lifting device, the droplet discharge head 17 and the cap device 51 are brought into contact with each other, the droplet discharge head 17 is sealed with the cap device 51, and the suction unit 50 is used. Suction of the droplet discharge head 17 is performed.

<Droplet ejection head>
Next, the droplet discharge head 17 will be described with reference to FIG. FIG. 2 is a diagram illustrating a configuration of the droplet discharge head. 2A is an external perspective view of the droplet discharge head viewed from the nozzle plate side, and FIG. 2B is a perspective cross-sectional view showing the structure around the pressure chamber of the droplet discharge head. 2C is a cross-sectional view showing the structure of the discharge nozzle portion of the droplet discharge head.

  As shown in FIG. 2A, the droplet discharge head 17 is connected to the liquid introduction part 41 having a pair of connection needles 42, a head substrate 43 that is continuous to the side of the liquid introduction part 41, and the liquid introduction part 41. A pump unit 45 and a nozzle plate 46 connected to the pump unit 45 are provided. A pipe connection member is connected to each connection needle 42 of the liquid introduction part 41, a liquid supply tube is connected via the pipe connection member, and functions from the functional liquid supply unit 4 connected to the liquid supply tube. Liquid is supplied. A pair of head connectors 47 are mounted on the head substrate 43, and a flexible flat cable (FFC cable) is connected via the head connectors 47. The droplet discharge head 17 is connected to the discharge device control unit 6 via an FFC cable, and signals are exchanged via the FFC cable. The pump unit 45 and the nozzle plate 46 constitute a substantially rectangular head main body 44.

  A flange portion 49 is formed in a square flange shape on the base portion side of the pump portion 45, that is, the base portion side of the head main body 44 so as to receive the liquid introduction portion 41 and the head substrate 43. A pair of screw holes (female screws) 49 a for fixing the droplet discharge head 17 is formed in the flange portion 49. The droplet discharge head 17 is fixed to the head holding member by a head set screw that passes through a head holding member for holding the droplet discharge head 17 and is screwed into the screw hole 49a.

  On the nozzle forming surface 46 a of the nozzle plate 46, two nozzle rows 48 </ b> A are formed which are formed on the nozzle plate 46 and include discharge nozzles 48 that discharge droplets. The two nozzle rows 48A are arranged in parallel to each other, and each nozzle row 48A is composed of, for example, 180 (schematically illustrated) discharge nozzles 48 arranged at an equal pitch. . Two nozzle rows 48A are arranged on the nozzle forming surface 46a of the head main body 44 with the center line therebetween.

  In a state where the droplet discharge head 17 is attached to the droplet discharge device 1, the nozzle row 48A extends in the Y-axis direction. The discharge nozzles 48 constituting the two nozzle rows 48A are displaced from each other by a half nozzle pitch in the Y-axis direction. One nozzle pitch is 140 μm, for example. At the same position in the X-axis direction, the liquid droplets discharged from the discharge nozzles 48 constituting each nozzle row 48A land on a straight line at equal intervals in the Y-axis direction by design. When the nozzle pitch of the discharge nozzles 48 in the nozzle row 48A is 140 μm, the center-to-center distance between the landing positions that are connected in a straight line is 70 μm in design.

As shown in FIGS. 2B and 2C, in the droplet discharge head 17, the pressure chamber plate 31 constituting the pump unit 45 is laminated on the nozzle plate 46, and the vibration plate 32 is disposed on the pressure chamber plate 31. Are stacked.
The pressure chamber plate 31 is formed with a liquid pool 35 that is always filled with the functional liquid supplied from the liquid introducing portion 41 via the liquid supply hole 33 of the vibration plate 32. The liquid pool 35 is a space surrounded by the diaphragm 32, the nozzle plate 46, and the wall of the pressure chamber plate 31. Further, the pressure chamber plate 31 is formed with a pressure chamber 38 partitioned by a head partition wall 37. A space surrounded by the diaphragm 32, the nozzle plate 46, and the two head partition walls 37 is a pressure chamber 38.

  The pressure chambers 38 are provided corresponding to the respective discharge nozzles 48, and the number of pressure chambers 38 and the number of discharge nozzles 48 are the same. The functional fluid is supplied from the liquid pool 35 to the pressure chamber 38 via the supply port 36 located between the two head partition walls 37. A set of the head partition wall 37, the pressure chamber 38, the discharge nozzle 48, and the supply port 36 is arranged in a line along the liquid pool 35, and the discharge nozzles 48 arranged in a line form a nozzle line 48A. . Although not shown in FIG. 2B, the discharge nozzles 48 arranged in one row are arranged in a substantially symmetrical position with respect to the liquid pool 35 with respect to the nozzle row 48 </ b> A including the discharge nozzle 48 shown in the figure, and the other nozzles. A row 48A is formed, and a set of the corresponding head partition wall 37, pressure chamber 38, and supply port 36 is arranged in one row.

One end of a piezoelectric element 39 is fixed to the portion of the diaphragm 32 that constitutes the pressure chamber 38. The other end of the piezoelectric element 39 is fixed to a base (not shown) that supports the entire droplet discharge head 17 via a fixing plate (not shown).
The piezoelectric element 39 has an active portion in which an electrode layer and a piezoelectric material are laminated. By applying a driving voltage to the electrode layer, the active portion is in the longitudinal direction (the diaphragm 32 in FIG. 2B or 2C). Shrink in the thickness direction). As the active portion contracts, the diaphragm 32 to which one end of the piezoelectric element 39 is fixed receives a force that is pulled to the opposite side of the pressure chamber 38. When the diaphragm 32 is pulled to the opposite side to the pressure chamber 38, the diaphragm 32 is bent to the opposite side of the pressure chamber 38. Thereby, since the volume of the pressure chamber 38 increases, the functional liquid is supplied from the liquid pool 35 to the pressure chamber 38 through the supply port 36. Next, when the driving voltage applied to the electrode layer is released, the active portion returns to the original length, and the piezoelectric element 39 presses the diaphragm 32. When the diaphragm 32 is pressed, it returns to the pressure chamber 38 side. As a result, the volume of the pressure chamber 38 suddenly returns to the original, that is, the increased volume is reduced, so that pressure is applied to the functional liquid filled in the pressure chamber 38, and the pressure chamber 38 communicates with the pressure chamber 38. The functional liquid is discharged as droplets from the discharge nozzle 48 formed in this manner.

  The discharge device control unit 6 controls the discharge of the functional liquid to each of the plurality of discharge nozzles 48 by controlling the voltage applied to the piezoelectric element 39, that is, by controlling the drive signal. More specifically, the volume of droplets ejected from the ejection nozzle 48, the number of droplets ejected per unit time, and the like can be changed. This makes it possible to change the distance between the droplets that have landed on the substrate, the amount of the functional liquid to land on a certain area on the substrate, and the like. For example, by selectively using the discharge nozzle 48 that discharges droplets from among the plurality of discharge nozzles 48 arranged in the nozzle row 48A, the range of the length of the nozzle row 48A in the extending direction of the nozzle row 48A. Thus, a plurality of droplets can be discharged simultaneously at the pitch interval of the discharge nozzles 48. In a direction substantially orthogonal to the extending direction of the nozzle row 48A, the substrate and the discharge nozzle 48 are relatively moved, and the discharge nozzle 48 is located at an arbitrary position on the substrate where the discharge nozzle 48 can face in the relative movement direction. It is possible to arrange liquid droplets discharged from the liquid crystal.

<Suction unit>
Next, the suction unit 50 will be described with reference to FIG. FIG. 3 is an explanatory diagram showing the configuration of the suction unit. FIG. 3A is an explanatory diagram showing the overall configuration of the suction unit, and FIG. 3B is an explanatory diagram showing the arrangement positions of the cap device and the liquid level sensor.
As shown in FIG. 3, the suction unit 50 includes a cap device 51, a cleaning liquid supply device 71, a drain device 81, and a liquid level sensor 91.

The cap device 51 includes a head cap 52, a cap support 61, and a supply / drainage pipe 66.
The head cap 52 includes a cap base 53, a sealing member 54, and an absorbent material 59. The cap base 53 is formed in a substantially rectangular parallelepiped shape with a material that is not easily corroded, such as stainless steel, and has a cap recess 56 formed on one surface. The cap recess 56 is a substantially rectangular parallelepiped recess that opens on one surface of the cap base 53. The cap base 53 is in a state where the opening of the cap recess 56 faces upward in the direction of gravitational acceleration when the head cap 52 is attached to the droplet discharge device 1.
In the cap base 53, a supply / drainage hole 57 penetrating the outer surface (lower surface) of the cap base 53 is opened on the bottom surface of the cap recess 56 opened to the upper side in the gravitational acceleration direction. A supply / drain liquid pipe 66 is connected to the opening of the supply / drain liquid hole 57 on the outer surface (lower surface) of the cap base 53. Thereby, the flow path formed in the supply / drainage pipe 66 communicates with the cap recess 56.

  The sealing member 54 is formed using a rubber-like elastic material having corrosion resistance against the functional liquid. The sealing member 54 has a frame shape having an outer shape and an inner opening whose shape in plan view is substantially similar to the shape of the opening of the cap recess 56, and is not shown along the edge of the opening of the cap recess 56. It is fixed to the cap base 53 by a sealing member holder. A sealing projection 54 a of the sealing member 54 protrudes from the upper surface of the cap base 53. The sealing chamber 54 and the cap recess 56 constitute a cap chamber 55.

The shape of the sealing projection 54a in plan view is a shape that abuts the nozzle forming surface 46a around the two nozzle rows 48A. When the head cap 52 comes into contact with the droplet discharge head 17, the sealing convex portion 54a protruding from the cap base 53 comes into contact with the nozzle forming surface 46a. At this time, the sealing convex portion 54a made of a rubber-like elastic material is elastically deformed and comes into close contact with the nozzle forming surface 46a. The cap chamber 55 is sealed by the droplet discharge head 17 as shown by a two-dot chain line in FIG. 3, and the liquid passage formed in the supply / discharge liquid hole 57 or the droplet discharge head 17. It becomes a sealed space which can communicate with the outside only through For the discharge nozzle 48, the cap chamber 55 is a sealing space for sealing the discharge nozzle 48.
An absorbent material 59 is disposed in the cap chamber 55. The absorbent material 59 is formed of a material capable of adsorbing and holding a liquid such as a porous material.

The cap support portion 61 includes a cap plate 62, a base holder 63, and a cap pressing mechanism 64.
A cap plate 62 is fixed to the droplet discharge device 1 via a moving plate of the moving device. A base holder 63 is fixed to the cap plate 62. A cap base hole is formed in the base holder 63, and the cap base 53 of the head cap 52 is loosely fitted in the cap base hole so as to be slidable in the vertical direction. The head cap 52 is attached so that the cap base 53 can move in the contact / separation direction with respect to the base holder 63 via the cap pressing mechanism 64.
The cap pressing mechanism 64 can be elastically deformed in a direction in which the head cap 52 moves in a direction substantially perpendicular to the surface of the cap plate 62 (a vertical direction when the cap device 51 is attached to the droplet discharge device 1). The head cap 52 is pressed in a direction away from the cap plate 62 by the drag force generated by the elastic deformation of the cap pressing mechanism 64, and the cap protrusion 53 a protruding from the cap base 53 comes into contact with the base holder 63. The direction position is fixed.

The cap pressing mechanism 64 is deformed by the contact force applied to the head cap 52 in a state where the head cap 52 is in contact with the droplet discharge head 17 and the like, and the head cap 52 is deformed by the deformation resistance and the like. A force for pressing the head cap 52 is applied to the head cap 52.
Due to the pressing force of the cap pressing mechanism 64, the sealing convex portion 54 a made of a rubber-like elastic material that is in contact with the droplet discharge head 17 is elastically deformed and reliably contacts the nozzle forming surface 46 a. Since the sealing projection 54a is in close contact with the nozzle forming surface 46a, the cap chamber 55 can reliably communicate with the outside only through the liquid supply / drain hole 57 or the liquid material flow path of the droplet discharge head 17. It becomes a sealing space for sealing the discharge nozzle 48.

  The liquid level sensor 91 includes a light emitting unit 91a and a light reception detecting unit 91b. The light emitting unit 91a includes a light emitting element. In the vertical direction, the light emitting portion 91a is disposed at a position where the center of the light beam emitted from the light emitting element passes substantially directly above the vertical direction of the sealing convex portion 54a of the sealing member 54. The light emitting portion 91a is disposed at a position facing the approximate center of the long side of the substantially rectangular sealing convex portion 54a in the horizontal direction. The light receiving detection unit 91b includes a light receiving element, and is disposed on a side opposite to the light emitting unit 91a with respect to the head cap 52 at a position where the light emitted from the light emitting element of the light emitting unit 91a can be detected by the light receiving element. Yes. The liquid level sensor 91 is a so-called photo interrupter, and when the light beam is blocked, the amount of light received by the light receiving detection unit 91b decreases, so that it is possible to detect the presence of an object at a position where the light beam is blocked. Further, the position in the direction orthogonal to the optical axis of the object that blocks the light flux can also be detected by the amount of decrease in the light amount. The liquid level sensor 91 corresponds to a liquid level detection unit.

  The cleaning liquid supply device 71 includes a relay tank 72, a liquid supply pipe 74, a liquid supply valve 76, a cleaning liquid supply tank 73, and a cleaning liquid pump 78. One end of the liquid supply pipe 74 is connected to the supply / drain liquid pipe 66, and the other end is connected to the relay tank 72. As described above, the supply / drain liquid pipe 66 communicates with the cap recess 56, and the relay tank 72 and the cap recess 56 communicate with each other via the supply liquid pipe 74 and the supply / drain liquid pipe 66. A liquid supply valve 76 is attached in the middle of the liquid supply pipe 74. The liquid supply valve 76 is controlled by the discharge device controller 6 to open and close the flow path of the liquid supply pipe 74. Also, the flow rate can be adjusted by adjusting the open state. The cleaning liquid is fed into the relay tank 72 from the cleaning liquid supply tank 73 by the cleaning liquid pump 78 and stored therein. When the liquid supply valve 76 is opened, the cleaning liquid is supplied from the relay tank 72 to the cap recess 56 by the pressure due to the difference between the cleaning liquid level in the relay tank 72 and the cleaning liquid level in the cap recess 56. The cleaning liquid supply device 71 corresponds to a cleaning liquid supply unit. The flow path of the liquid supply pipe 74 corresponds to the supply flow path, and the liquid supply valve 76 corresponds to the supply path opening / closing means. The relay tank 72 corresponds to a cleaning liquid tank.

The drainage device 81 includes a drainage tank 82, a drainage pipe 84, a drainage valve 86, and a suction pump 88.
One end of the drainage pipe 84 is connected to the supply / drainage pipe 66, and the other end is connected to the drainage tank 82. As described above, the supply / drainage pipe 66 communicates with the cap recess 56, and the drainage tank 82 and the cap recess 56 communicate with each other via the drainage pipe 84 and the supply / drainage pipe 66. A drainage valve 86 is attached in the middle of the drainage pipe 84. The drain valve 86 is controlled by the discharge device controller 6 to open and close the flow path of the drain pipe 84. A suction pump 88 is connected to the drainage tank 82. By suctioning with the suction pump 88, the inside of the drainage tank 82 can be set to a negative pressure.
By making the inside of the drainage tank 82 have a negative pressure by the suction pump 88, the gas or liquid in the cap recess 56 communicating with the drainage tank 82 can be sucked into the drainage tank 82 from the cap recess 56.
As described above, in a state where the head cap 52 is in contact with the liquid droplet ejection head 17, the cap chamber 55 including the cap recess 56 passes through the supply / discharge liquid hole 57 or the liquid material flow path of the liquid droplet ejection head 17. This is a sealing space that seals the discharge nozzle 48 that can communicate with the outside only through the gap. By operating the suction pump 88 to make the inside of the drainage tank 82 have a negative pressure, the cap chamber 55 is made to have a negative pressure, thereby sucking the functional liquid present in the liquid material flow path of the droplet discharge head 17. be able to. The drainage device 81 corresponds to a suction unit. The flow path of the drain pipe 84 corresponds to the suction flow path, and the drain valve 86 corresponds to the suction path opening / closing means.

<Washing process>
Next, a cleaning process for cleaning the cap chamber 55 and the like will be described with reference to FIGS. FIG. 4 is a flowchart showing a cleaning process for cleaning the cap chamber and the like using the cleaning liquid. FIG. 5 is an explanatory diagram showing a state in which the liquid level of the cleaning liquid in the cap chamber is detected by the liquid level sensor.
In step S <b> 21 of FIG. 4, the cleaning liquid is supplied to the relay tank 72. As described above, the cleaning liquid is supplied from the cleaning liquid supply tank 73 by the cleaning liquid pump 78 and stored in the relay tank 72. As the cleaning liquid, for example, a main solvent of a functional liquid is used. The cleaning liquid is supplied at least in such an amount that the level of the cleaning liquid in the relay tank 72 is higher than the upper end of the sealing convex portion 54 a of the sealing member 54.

Next, in step S22, the drain valve 86 is closed.
Next, in step S23, the liquid supply valve 76 is opened.
Next, in step S <b> 24, a cleaning liquid is supplied to the cap chamber 55. As described above, when the liquid supply valve 76 is opened, the relay tank 72 and the cap recess 56 communicate with each other via the liquid supply pipe 74 and the supply / drain liquid pipe 66. The cleaning liquid is supplied to the relay tank 72 by an amount such that the level of the cleaning liquid in the relay tank 72 is higher than the upper end of the sealing convex portion 54a of the sealing member 54. To the cap recess 56 of the cap chamber 55. Note that the amount of the cleaning liquid supplied in advance to the relay tank 72 is the same as the upper end of the sealing convex portion 54 a of the sealing member 54 when the cap chamber 55 is substantially filled with the cleaning liquid. By setting the amount so as to decrease to near, the supply amount of the cleaning liquid per hour at the time can be reduced.

Next, in step S25, the liquid level of the cleaning liquid supplied to the cap chamber 55 is detected by the liquid level sensor 91, and it is determined whether or not the liquid level has been detected. As described above, in the liquid level sensor 91, the center of the light beam emitted from the light emitting unit 91a passes substantially directly above the sealing convex portion 54a of the sealing member 54, and the light receiving detection unit 91b receives the light beam. It is disposed at a detectable position. In a state where the cap chamber 55 is not filled with the cleaning liquid, most of the light beams emitted from the light emitting unit 91a reach the light receiving detection unit 91b as indicated by the broken arrow a in FIG.
When the cap chamber 55 is filled with the cleaning liquid, as shown in FIG. 5B, the cleaning liquid that does not enter the cap chamber 55 rises from the opening of the sealing convex portion 54a due to the surface tension. The light beam emitted from the light emitting portion 91a and passing substantially right above the sealing convex portion 54a is blocked at least partially by the raised cleaning liquid as shown by the arrow b in FIG. The amount of light received by the detector 91b decreases. The liquid level of the cleaning liquid can be detected by the output of the light receiving detector 91b, and by detecting the liquid level of the cleaning liquid, a part of the liquid level of the cleaning liquid can be opened in the sealing projection 54a of the cap chamber 55. It is possible to detect that the cap chamber 55 is filled with the cleaning liquid. In a state where the cap chamber 55 is filled with the cleaning liquid, the deposits adhered to the inner surface of the cap chamber 55 and the absorbent material 59 are dissolved in the cleaning liquid, and the inside of the cap chamber 55 is cleaned.

If the liquid level cannot be detected in step S25 (NO in step S25), the process returns to step S24, and step S24 is continued.
If the liquid level can be detected in step S25 (YES in step S25), the process proceeds to step S26.

In step S26 after step S25, the liquid supply valve 76 is closed. By closing the liquid supply valve 76, the supply of the cleaning liquid to the cap chamber 55 is stopped.
Next, in step S27, drainage suction for discharging the cleaning liquid that has cleaned the inside of the cap chamber 55 is started. As described above, the inside of the drainage tank 82 is set to a negative pressure by being sucked by the suction pump 88.
Next, in step S28, the drain valve 86 is opened.

Next, in step S <b> 29, the cap chamber 55 is cleaned, and the cleaning liquid containing the deposits and the like attached to the cap chamber 55 is discharged.
Since the drain valve 86 is opened, the drain tank 82 and the cap recess 56 communicate with each other via the drain pipe 84 and the supply / drain pipe 66 as described above. Since the inside of the drainage tank 82 has become a negative pressure by being sucked by the suction pump 88, the cleaning liquid containing deposits and the like filled in the cap chamber 55 is discharged to the drainage tank 82. The cleaning liquid is discharged over a period of time sufficient to discharge the cleaning liquid including the deposits in the cap chamber 55 and the like.

In step S30 subsequent to step S29, it is determined whether or not a predetermined number of times of cleaning have been performed, that is, whether or not the cleaning process for performing each step from step S22 to step S29 has been performed a specified number of times. .
If the designated number of times of cleaning has not been performed (NO in step S30), the process returns to step S22, and the processes from step S22 to step S29 are repeated. At this time, if the amount of the cleaning liquid supplied to the relay tank 72 is less than the amount necessary to repeat each step from step S22 to step S29, the process returns to step S21, and each step from step S21 to step S29. repeat.
If the pre-designated number of times of cleaning has already been performed (YES in step S30), the cleaning process of cleaning the cap chamber 55 and the like using the cleaning liquid is terminated.

<Head unit>
Next, a schematic configuration of the head unit 121 included in the discharge unit including the plurality of droplet discharge heads 17 will be described with reference to FIG. FIG. 6 is a plan view showing a schematic configuration of the head unit. The X axis and the Y axis shown in FIG. 6 are the same as the X axis and the Y axis shown in FIG. It coincides with the X axis and the Y axis of the droplet discharge device in the same direction.

  As shown in FIG. 6, the head unit 121 includes a carriage plate 123 and six droplet discharge heads 17 mounted on the carriage plate 123. The droplet discharge head 17 is fixed to the carriage plate 123, the head main body 44 is loosely fitted in a hole (not shown) formed in the carriage plate 123, and the nozzle plate 46 (head main body 44) is fixed to the carriage plate. It protrudes from the surface of 123. FIG. 6 is a view as seen from the nozzle plate 46 (nozzle forming surface 46a) side. The six droplet discharge heads 17 are divided in the Y-axis direction to form two groups of head groups 125 each having three droplet discharge heads 17. The nozzle row 48A of each droplet discharge head 17 extends in the Y-axis direction.

  The three droplet discharge heads 17 included in one head set 125 are more than the discharge nozzles 48 at the ends of one droplet discharge head 17 of the droplet discharge heads 17 adjacent to each other in the Y-axis direction. The discharge nozzle 48 at the end of one droplet discharge head 17 is positioned so as to be shifted by a half nozzle pitch. If the positions of all the discharge nozzles 48 in the X-axis direction are the same in the three droplet discharge heads 17 included in the head set 125, the discharge nozzles 48 are arranged at equal intervals of a half nozzle pitch in the Y-axis direction. . In other words, at the same position in the X-axis direction, the droplets ejected from the ejection nozzles 48 constituting each nozzle row 48A included in each droplet ejection head 17 are arranged at equal intervals in the Y-axis direction by design. To land on a straight line. Since the droplet discharge heads 17 overlap each other in the Y-axis direction, a head set 125 is configured in a stepwise manner in the X-axis direction.

<Cap unit>
Next, a schematic configuration of the cap unit 151 including a plurality of head caps 52 corresponding to the plurality of droplet discharge heads 17 of the head unit 121 will be described with reference to FIG. FIG. 7 is a plan view showing a schematic configuration of the cap unit. The X-axis and Y-axis shown in FIG. 7 are the same as the X-axis and Y-axis shown in FIG. 6 in a state where the cap unit 151 is attached to the droplet discharge device having substantially the same configuration as the droplet discharge device 1. Match.

The cap unit 151 includes a head cap 52, a cap support portion 161, and a supply / drainage pipe 66 (see FIG. 3).
The cap unit 151 includes six sets of the head cap 52 and the supply / drainage pipe 66 provided in the cap device 51 described above.

The cap support portion 161 includes a cap unit plate 162, a base holder 63, and a cap pressing mechanism 64 (see FIG. 3).
The cap unit plate 162 is fixed to the droplet discharge device via a moving mechanism. Six base holders 63 are fixed to the cap unit plate 162. A head cap 52 is fixed to the base holder 63 in the same manner as the cap device 51 described above. Similar to the cap device 51, the head cap 52 forms a sealing space for sealing the discharge nozzle 48 of the droplet discharge head 17 by the pressing force of the cap pressing mechanism 64.
Each of the six head caps 52 is disposed on the cap unit plate 162 at a position where the six droplet discharge heads 17 of the head unit 121 can be simultaneously sealed by the six head caps 52.
Corresponding to each head cap 52, a cleaning liquid supply device 71 and a drainage device 81 similar to the suction unit 50 are provided.
One liquid level sensor 91 is provided for each head cap 52 so that the liquid level in each of the six head caps 52 can be detected.

<Example of liquid level sensor arrangement>
Next, with respect to the position where the liquid level sensor 91 is disposed, an example different from the above-described position will be described with reference to FIG. FIG. 8 is an explanatory diagram showing the positional relationship between the head cap and the liquid level sensor. FIG. 8A is an explanatory diagram showing the position of the liquid level sensor with respect to the head cap, and FIG. 8B is an explanatory diagram showing a state in which the liquid level of the cleaning liquid in the cap chamber is detected by the liquid level sensor. .

As shown in FIG. 8A, the vertical position of the liquid level sensor 91 is such that the center of the light beam emitted from the light emitting portion 91a passes almost directly above the sealing convex portion 54a of the sealing member 54. Thus, the light beam is disposed at a position where the light receiving detector 91b can detect the light beam.
The distance from the center of the light beam to the upper surface in the vertical direction of the light emitting portion 91a or the light receiving detection portion 91b is not sufficiently small as compared with the protruding amount of the droplet discharge head 17 from the carriage plate 126. For this reason, when the carriage plate 126 and the light emitting portion 91a or the light receiving detection portion 91b are disposed at positions where they overlap each other in the plane direction, when the droplet discharge head 17 is sealed by the head cap 52, the carriage plate 126 and The light emitting unit 91a or the light receiving detection unit 91b interferes. Therefore, in the liquid level sensor 91 shown in FIG. 8, the light emitting unit 91a and the light receiving detection unit 91b are arranged at positions where they do not overlap the carriage plate 126 in the planar direction.

In the state where the cap chamber 55 is not filled with the cleaning liquid by using a light emitting element that can emit light having an intensity that can reach the light receiving detection unit 91b at a distant position, a broken line arrow c in FIG. As shown, most of the light beam emitted from the light emitting unit 91a reaches the light receiving detection unit 91b.
When the cap chamber 55 is filled with the cleaning liquid, as shown in FIG. 8B, the cleaning liquid overflowing from the cap chamber rises from the opening of the sealing projection 54a due to the surface tension. The light beam emitted from the light emitting portion 91a and passing substantially right above the sealing convex portion 54a is at least partially blocked by the raised cleaning liquid as shown by the arrow d in FIG. The amount of light received by the detector 91b decreases. The liquid level of the cleaning liquid can be detected by the output of the light receiving detector 91b.

According to the embodiment, the effects described below can be obtained.
(1) The cleaning liquid can be supplied to the head cap 52 by the cleaning liquid supply device 71. By immersing the cap chamber 55 with the cleaning liquid, it is possible to clean the deposits and the like in the portion immersed in the cleaning liquid.

  (2) The liquid level sensor 91 can detect the liquid level in which the cap chamber 55 is filled with the cleaning liquid and the cleaning liquid is raised by the surface tension from the opening of the sealing convex portion 54a. Accordingly, the cleaning liquid can be supplied to the head cap 52 in a state where the cap chamber 55 is filled with the cleaning liquid and the cleaning liquid does not overflow from the cap chamber 55. By filling the cap chamber 55 with the cleaning liquid, the entire cap chamber 55 can be cleaned.

  (3) The cleaning liquid supply device 71 includes a liquid supply valve 76 that can open and close the flow path of the liquid supply pipe 74. By using the liquid supply valve 76, the supply of the cleaning liquid from the relay tank 72 to the head cap 52 can be quickly stopped. Thereby, it can be suppressed that an excessive amount of cleaning liquid is supplied after it is detected that an appropriate amount of cleaning liquid has been supplied to the head cap 52. Moreover, it can suppress that a washing | cleaning liquid flows backward.

  (4) The drainage device 81 includes a drainage valve 86 that opens and closes the flow path of the drainage pipe 84. By closing the drainage valve 86, it is possible to prevent the cleaning liquid from naturally flowing out from the supply / drainage pipe 66.

  (5) The liquid level sensor 91 is disposed at a position where the light emitting portion 91a faces the approximate center of the long side of the substantially rectangular sealing convex portion 54a in the horizontal direction. It is arranged at a position where the emitted light beam can be detected. When the cleaning liquid swells from the opening of the sealing convex portion 54a due to surface tension, the center is the highest. Therefore, the light emitting portion 91a is disposed at a position facing the approximate center of the long side of the sealing convex portion 54a. In this case, the liquid level can be detected efficiently.

  (6) The cleaning liquid is supplied from the relay tank 72 to the cap chamber 55 by the pressure due to the difference between the cleaning liquid level in the relay tank 72 and the cleaning liquid level in the cap chamber 55. As the cleaning liquid is supplied, the liquid level in the relay tank 72 is lowered and the liquid level in the cap chamber 55 is raised. Therefore, the pressure due to the difference in liquid level is reduced, and the supply amount per unit time is reduced. Thereby, the supply amount per unit time at the time of stopping the supply can be reduced and the time tolerance at the time of stopping the supply can be increased.

  As mentioned above, although preferred embodiment was described referring an accompanying drawing, suitable embodiment is not restricted to the said embodiment. It goes without saying that various changes can be made without departing from the scope of the invention, and the following can also be implemented.

  (Modification 1) In the above embodiment, the liquid level sensor 91 is disposed at a position where the light emitting portion 91a faces the approximate center of the long side of the substantially rectangular sealing convex portion 54a, thereby sealing the cleaning liquid. The liquid level at the highest position is detected when it rises due to surface tension from the opening of the convex portion 54a. However, it is not essential that the liquid level sensor is disposed at a position facing the long side or near the center of the side. Since the liquid level raised by the surface tension has the highest center of gravity position of the opening, any liquid level may be used as long as the liquid level at the center of gravity of the opening is detected.

  (Modification 2) In the above-described embodiment, the liquid level sensor 91 is a photo interrupter, and the liquid level is detected by the light beam being blocked by the cleaning liquid. It is not essential to detect blocking. The liquid level may be detected by detecting a member that moves up and down following the position of the liquid level, such as a member floating on the liquid level.

  (Modification 3) In the above embodiment, the liquid level sensor 91 is a photo interrupter, and the liquid level is detected by blocking the light beam by the cleaning liquid. However, the light beam is blocked to detect the liquid level. It is not essential to detect that. For example, when the position of the liquid level reaches a predetermined position, each component of the liquid level sensor is disposed at a position where the light beam emitted from the light emitting element and reflected by the liquid level can be received by the light receiving element. Also good.

  (Modification 4) In the embodiment, the liquid level sensor 91 is provided for each head cap 52 and the liquid level is detected for each individual head cap 52. However, the liquid level is detected for each individual head cap 52. It is not essential to detect. The liquid level in the plurality of head caps may be detected by a single liquid level sensor. When the liquid level is different among the plurality of head caps, for example, the liquid level with the highest liquid level is detected.

  (Modification 5) In the above-described embodiment, a single cleaning liquid supply device 71 and a drainage device 81 are provided for each head cap 52 of the plurality of head caps 52 provided in the cap unit 151. It is not essential to provide a cleaning liquid supply device and a drainage device for each of the plurality of head caps. The structure which provides a common washing | cleaning liquid supply apparatus and a drainage apparatus with respect to several head caps may be sufficient. In the configuration in which a common cleaning liquid supply device is provided for a plurality of head caps, as in the above-described embodiment, the cleaning liquid is determined by the pressure due to the difference between the cleaning liquid level in the relay tank and the cleaning liquid level in the cap chamber. By making it the structure which supplies, it can make it easy to make the liquid level of the washing | cleaning liquid in a some cap chamber uniform.

  (Modification 6) In the above-described embodiment, the cleaning liquid supply device 71 includes the liquid supply valve 76 that opens and closes the flow path of the liquid supply pipe 74, but the cleaning liquid supply apparatus is an apparatus that opens and closes the flow path of the cleaning liquid. It is not essential to prepare. For example, the supply state of the cleaning liquid may be controlled by controlling the operating state of the drive source of the liquid supply apparatus.

  (Modification 7) In the above-described embodiment, the drainage device 81 includes the drainage valve 86 that opens and closes the flow path of the drainage pipe 84, but the drainage device opens and closes the drainage flow path. It is not essential to have For example, the supply state of the cleaning liquid may be controlled by controlling the operating state of the driving source of the drainage device.

  (Modification 8) In the above-described embodiment, the cleaning liquid is supplied from the relay tank 72 to the cap chamber 55 by the pressure due to the difference between the liquid level of the cleaning liquid in the relay tank 72 and the liquid level of the cleaning liquid in the cap chamber 55. It was a configuration. However, it is not essential to provide a relay tank or supply the cleaning liquid using the difference in liquid level. The cleaning liquid may be supplied directly from the cleaning liquid storage tank to the head cap by the driving source of the liquid supply apparatus.

  (Modification 9) In the above embodiment, the cleaning liquid is the main solvent of the functional liquid, but it is not essential that the cleaning liquid is the main solvent of the functional liquid. Any liquid material can be used as long as it can clean the head cap by dissolving the adhering matter adhering to the head cap or by peeling it from the surface of the head cap.

  (Modification 10) In the above embodiment, the cap device 51 includes the supply / drain liquid pipe 66 communicating with the cap recess 56, and the liquid supply pipe 74 of the cleaning liquid supply apparatus 71 and the drain pipe 84 of the drain apparatus 81 are The cap recess 56 communicated with the supply / drain pipe 66. However, it is not essential that the suction flow path of the suction means and the supply flow path of the cleaning liquid supply means are connected to the head cap via a common flow path. The suction channel and the supply channel may be individually connected to the head cap.

  (Modification 11) In the above embodiment, the droplet discharge head 17 is an inkjet droplet discharge head, but it is not essential that the liquid discharge head is an inkjet droplet discharge head. The liquid discharge head for disposing the liquid may be a discharge head of a method different from the ink jet method.

  (Modification 12) In the above embodiment, the droplet discharge head 17 is configured to discharge one type of functional liquid, but the type of liquid material discharged by the droplet discharge head is not limited to one. The liquid droplet ejection head may have a configuration including a plurality of liquid material supply paths and nozzle rows that can connect the liquid material supply paths and supply the liquid material.

  (Modification 13) In the embodiment described above, the droplet discharge head 17 includes two nozzle rows 48A, and each nozzle row 48A has a configuration including 180 discharge nozzles 48. The configuration of the ejection nozzle in the ejection head is not limited to the configuration in the droplet ejection head 17. The number of discharge nozzles included in the droplet discharge head may be any number, and the arrangement of discharge nozzles in the droplet discharge head may be any arrangement, for example, arranged in one row.

  (Modification 14) In the embodiment described above, the head unit 121 of the droplet discharge device includes the six droplet discharge heads 17, but the number of droplet discharge heads included in the head unit is limited to six. Absent. The head unit may be configured to include any number of droplet discharge heads. The number of head caps in the cap unit corresponding to the head unit may also include any number of head caps corresponding to the number of droplet discharge heads in the head unit.

  (Modification 15) In the above-described embodiment, the droplet discharge device 1 includes one head unit 21, but the liquid discharge device includes not only one head unit. The liquid material ejection device may be configured to include any number of head units.

  DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus, 2 ... Drawing unit, 5 ... Maintenance unit, 17 ... Droplet discharge head, 21 ... Head unit, 46 ... Nozzle plate, 46a ... Nozzle formation surface, 48 ... Discharge nozzle, 48A ... Nozzle row, DESCRIPTION OF SYMBOLS 50 ... Suction unit, 51 ... Cap apparatus, 52 ... Head cap, 53 ... Cap base, 54 ... Sealing member, 54a ... Sealing convex part, 55 ... Cap chamber, 56 ... Cap recessed part, 57 ... Supply / drain liquid hole, DESCRIPTION OF SYMBOLS 61 ... Cap support part, 64 ... Cap press mechanism, 66 ... Supply / drain liquid pipe, 71 ... Cleaning liquid supply apparatus, 72 ... Relay tank, 74 ... Liquid supply pipe, 76 ... Liquid supply valve, 81 ... Liquid discharge apparatus, 82 ... Drainage tank, 84 ... drainage pipe, 86 ... drainage valve, 88 ... suction pump, 91 ... liquid level sensor, 91a ... light emission part, 91b ... light reception detection part.

Claims (16)

A liquid discharge head comprising a discharge nozzle for discharging the liquid;
A head cap that seals a nozzle forming surface on which the discharge nozzle of the liquid discharge head is formed;
A suction means that communicates with the head cap and sucks the gas or liquid in the head cap;
A cleaning liquid supply means that communicates with the head cap and supplies a cleaning liquid into the head cap;
And a liquid level detecting means for detecting a liquid level of the liquid in the head cap.   2. The liquid material ejecting apparatus according to claim 1, wherein the liquid level detecting means is disposed at a position where it can be detected that the liquid level reaches the height of the edge of the head cap.   2. The liquid level detection unit according to claim 1, wherein the liquid level detection unit is disposed at a position where the liquid level of the liquid in the head cap can be detected from a portion where the liquid level of the head cap rises from the edge of the head cap due to surface tension. The liquid material discharge apparatus as described.   The liquid level detection means is disposed at a position where the liquid level of the liquid at the center of gravity of the shape of the head cap in a plane direction orthogonal to the vertical direction can be detected. The liquid discharge apparatus as described in any one of these. The suction means includes a suction flow path communicating with the head cap;
The liquid discharge device according to claim 1, further comprising: a suction path opening / closing means capable of opening and closing the suction channel. The cleaning liquid supply means includes a supply flow path communicating with the head cap,
The liquid discharge apparatus according to claim 1, further comprising a supply path opening / closing means capable of opening and closing the supply flow path.   The cleaning liquid supply means includes a cleaning liquid tank that stores the cleaning liquid, and the liquid level of the cleaning liquid in the cleaning liquid tank is relatively higher in the vertical direction than the liquid level in the head cap. The liquid discharging apparatus according to any one of claims 1 to 6, wherein the cleaning liquid is supplied.   The liquid discharge apparatus according to claim 1, wherein the cleaning liquid is a main solvent of a functional liquid discharged from the liquid discharge head. A head cap for sealing a nozzle forming surface on which the discharge nozzles of a liquid discharge head including a discharge nozzle for discharging a liquid are formed;
A suction means that communicates with the head cap and sucks the gas or liquid in the head cap;
A cleaning liquid supply means that communicates with the head cap and supplies a cleaning liquid into the head cap;
And a liquid level detecting means for detecting a liquid level of the liquid in the head cap.   10. The head maintenance apparatus according to claim 9, wherein the liquid level detecting means is disposed at a position where it can be detected that the liquid level has reached the edge height of the head cap.   10. The liquid level detecting means according to claim 9, wherein the liquid level detecting means is disposed at a position where a liquid level of the liquid in the head cap can be detected from a portion where the liquid level of the liquid is raised from the edge of the head cap due to surface tension. The head maintenance device described.   12. The liquid level detecting means is disposed at a position where the liquid level of the liquid at the center of gravity of the shape of the head cap in a plane direction orthogonal to the vertical direction can be detected. The head maintenance device according to any one of the above. The suction means includes a suction flow path communicating with the head cap;
The head maintenance device according to any one of claims 9 to 12, further comprising suction path opening / closing means capable of opening and closing the suction channel. The cleaning liquid supply means includes a supply flow path communicating with the head cap,
The head maintenance device according to claim 9, further comprising: a supply path opening / closing means capable of opening and closing the supply flow path.   The cleaning liquid supply means includes a cleaning liquid tank that stores the cleaning liquid, and the liquid level of the cleaning liquid in the cleaning liquid tank is relatively higher in the vertical direction than the liquid level in the head cap. The head maintenance device according to claim 9, wherein the cleaning liquid is supplied.   The head maintenance device according to claim 9, wherein the cleaning liquid is a main solvent of a functional liquid ejected from the liquid material ejection head.

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