Liquid droplet ejecting apparatus, electro-optical device, method of manufacturing the electro-optical device, and electronic apparatus

A liquid droplet ejecting apparatus of the present invention includes a cleaning unit, a regular flushing unit, capping unit, and an ejection-amount measuring unit as droplet ejecting head maintenance units used for function maintenance, function recovery, adjustment, or inspection of a liquid ejecting head. The droplet ejecting head maintenance units are arranged in a group in a movable platen as a maintenance-unit installing section. The movable platen is supported by an accessory stand physically separated from a main body.

FIELD OF THE INVENTION

The present invention relates to a liquid droplet ejecting apparatus, an electro-optical device, a method of manufacturing the electro-optical device, and an electronic apparatus.

DESCRIPTION OF THE RELATED ART

Industrial liquid droplet ejecting apparatuses (ink-jet imaging apparatuses) are used for manufacturing, for example, color filters for liquid crystal display devices or organic EL (electroluminescent) display devices, or for forming metal wiring lines on substrates, by adapting an ink-jet method (a liquid droplet ejecting method) for ink-jet printers

In the liquid droplet ejecting apparatuses, there is a need for providing various units (hereinafter, referred to as droplet ejecting head maintenance units) used for function maintenance, function recovery, adjustment, or inspection of droplet ejecting heads (ink-jet heads). The droplet ejecting head maintenance units can include, for example, a cleaning unit for cleaning a nozzle-formed surface of the droplet ejecting head, a capping unit for suctioning liquid discharged from the droplet ejecting head, etc.

Since the industrial liquid droplet ejecting apparatuses increase in size with an increase in the size of substrates, however, there is a problem in that wide installation spaces are necessary within plants. With an increase in size of the liquid droplet ejecting apparatuses, there is an problem in that an installation space should be secured for each of the various droplet ejecting head maintenance units described above.

Therefore, it is desirable to provide a liquid droplet ejecting apparatus in which the entire space for the apparatus can be effectively utilized by arranging a plurality of droplet ejecting head maintenance units with high spatial efficiency, an electro-optical device manufactured using the liquid droplet ejecting apparatus, a method of manufacturing an electro-optical device using the liquid droplet ejecting apparatus, and an electronic apparatus comprising the electro-optical device.

SUMMARY OF THE INVENTION

The above object is accomplished by the following present invention.

A liquid droplet ejecting apparatus according to the present invention includes: a main body; a work piece mounting unit on which a work piece is mounted; a droplet ejecting head for ejecting liquid droplets of an ejection liquid to the work piece; a relative movement mechanism for relatively moving the work piece mounting unit and the droplet ejecting head; and three or more kinds of droplet ejecting head maintenance units used for function maintenance, function recovery, adjustment, or inspection of the droplet ejecting head, wherein at least three of the droplet ejecting head maintenance units are arranged in a group in a maintenance-unit installing section. As a result, by arranging the plurality of droplet ejecting head maintenance units with high spatial efficiency, it is possible to provide a liquid droplet ejecting apparatus for which the entire space can be effectively utilized. Further, since maintenance by means of various kinds of droplet ejecting head maintenance units in the maintenance-unit installing section can be performed in a group, the cycle time required for one work piece can be shortened, so that it is possible to improve throughput (production efficiency).

It is preferable that the liquid droplet ejecting apparatus according to the present invention include four or more kinds of droplet ejecting head maintenance units, and that at least four droplet ejecting head maintenance units be arranged in a group in the maintenance-unit installing section. As a result, it is possible to more effectively utilize the entire space for the apparatus, and to further improve throughput.

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that each of the droplet ejecting head maintenance units installed in the maintenance-unit installing section be one of a cleaning unit for cleaning a nozzle-formed surface of the droplet ejecting head, a flushing unit having a liquid receiver for receiving liquid wastefully ejected by the droplet ejecting head during a waiting time, a capping unit having a cap for covering a nozzle-formed surface of the droplet ejecting head while suctioning fluid from the droplet ejecting head, an ejection-amount measuring unit used for measuring the amount of liquid droplets ejected from the droplet ejecting head, and a dot-omission detecting unit used for inspecting dot-omission of the droplet ejecting head. As a result, by arranging the cleaning unit, the flushing unit, the capping unit, the ejection-amount measuring unit, and the dot-omission detecting unit with high spatial efficiency, it is possible to effectively utilize the entire space for the apparatus.

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that the droplet ejecting head maintenance units installed in the maintenance-unit installing section be arranged in parallel in a line. As a result, it is possible to more effectively utilize the entire space for the apparatus, and to further improve throughput.

It is preferable that the liquid droplet ejecting apparatus according to the present invention further include a maintenance-unit moving mechanism for horizontally moving the maintenance-unit installing section. As a result, since the degree of freedom regarding the pattern in which the droplet ejecting head maintenance units are arranged in the maintenance-unit installing section is enhanced, it is possible to more effectively utilize the entire space for the apparatus.

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that the droplet ejecting head be detachably provided in the main body, and that the maintenance-unit moving mechanism move the maintenance-unit installing section to a position where the droplet ejecting head maintenance units installed in the maintenance-unit installing section do not interfere with the droplet ejecting head during the attachment or detachment of the droplet ejecting head. As a result, the attachment or detachment of the droplet ejecting head can be performed easily, smoothly and rapidly, so that it is possible to improve workability.

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that the relative movement mechanism comprise an Y-axis movement mechanism for moving the work piece mounting unit in a horizontal direction (hereinafter referred to as a ‘Y-axis direction’) relative to the main body, and an X-axis movement mechanism for moving the droplet ejecting head in another horizontal direction (hereinafter referred to as an ‘X-axis direction’) perpendicular to the Y-axis direction relative to the main body. As a result, various kinds of patterns can be formed (imaged) on the work piece in accordance with its purposes.

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that the liquid droplets be ejected to the work piece from the droplet ejecting head while relatively moving the work mounting unit and the droplet ejecting head, using either the Y-axis direction or the X-axis direction as the primary scanning direction and the other as the secondary scanning direction. As a result, various patterns can be formed (imaged) on the work in accordance with its purposes.

It is preferable that the liquid droplet ejecting apparatus according to the present invention further include a maintenance-unit moving mechanism for moving the maintenance-unit installing section in the Y-axis direction, and that the droplet ejecting head maintenance units installed in the maintenance-unit installing section be arranged in a line along the Y-axis direction. As a result, it is possible to more effectively utilize the entire space for the apparatus, and to further improve throughput.

It is preferable that the liquid droplet ejecting apparatus according to the present invention further include a height adjusting mechanism for adjusting the height of the maintenance-unit installing section. As a result, it is possible to easily cope with a change in height of the droplet ejecting head due to a change in thickness of the work piece to be manufactured (processed).

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that the work piece mounting unit, the droplet ejecting head, and the relative movement mechanism be supported by the main body, and that the maintenance-unit installing section be supported by an accessory stand physically separated from the main body. As a result, vibrations generated from the accessory stand side can be prevented from being transferred to the main body side. As such, it is possible to avoid an adverse effect on the accuracy of the pattern to be formed (imaged) on the work piece.

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that the main body have a surface plate, and that the work piece mounting unit, the droplet ejecting head, and the relative movement mechanism be supported by the surface plate. As a result, it is possible to form (image) a pattern with high accuracy on the work piece.

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that a side surface of the accessory stand be provided with relevant piping components used for the liquid droplet ejecting apparatus, and that the relevant piping components be provided to not protrude outwardly from the total width of the accessory stand by fixing the relevant piping components to fixed sections provided at positions receding inwardly from the total width of the accessory stand. As a result, when an operator works in the vicinity of the accessory stand, it is possible to easily and smoothly work without interference with the relevant piping components.

In the liquid droplet ejecting apparatus according to the present invention, it is preferable that a predetermined pattern be formed on the work piece by ejecting the liquid droplets from the droplet ejecting head while relatively moving the work piece mounting unit and the droplet ejecting head.

As a result, various patterns can be formed (imaged) on the work piece in accordance with its purposes.

An electro-optical device according to the present invention is manufactured using the liquid droplet ejecting apparatus according to the present invention. As a result, it is possible to provide an electro-optical device having high-performance elements on which patterns are formed (imaged) with high accuracy, and having a low manufacturing cost.

A method of manufacturing an electro-optical device according to the present invention employs the liquid droplet ejecting apparatus according to the present invention. As a result, it is possible to provide a method of manufacturing an electro-optical device, wherein patterns can be formed (imaged) on the work piece with high accuracy, and its manufacturing cost can be reduced.

An electronic apparatus according to the present invention comprises the electro-optical device according to the present invention. As a result, it is possible to provide an electronic apparatus having high-performance elements, on which patterns are formed (imaged) with high accuracy, and having a low manufacturing cost.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, a liquid droplet ejecting apparatus according to the present invention will be described in detail and in conjunction with the preferred embodiments shown in the accompanying drawings.

FIGS. 1 and 2are a plan view and a side view illustrating an embodiment of a liquid droplet ejecting apparatus according to the present invention, respectively; andFIG. 9is a perspective view illustrating a tank housing unit in the liquid droplet ejecting apparatus shown inFIGS. 1 and 2. Hereinafter, for the purpose of convenient explanation, one horizontal direction (the direction corresponding to the right-left direction inFIGS. 1 and 2) is referred to as a ‘Y-axis direction’, and another horizontal direction (the direction corresponding to an up-down direction inFIG. 1), perpendicular to the Y-axis direction, is referred to as an ‘X-axis direction’. Further, in the Y-axis direction, movement to the right inFIGS. 1 and 2is referred to as ‘Y-axis advancement’, and movement to the left inFIGS. 1 and 2is referred to as ‘Y-axis retreat’. Furthermore, in the X-axis direction, downward movement inFIG. 1is referred to as ‘X-axis advancement’, and upward movement inFIG. 1is referred to as ‘X-axis retreat’.

The liquid droplet ejecting apparatus1is an apparatus for ejecting liquid (liquid to be ejected) such as ink, functional liquid containing target materials, etc., in a minute liquid droplet state to a substrate W as a work piece by using an ink-jet method (a liquid droplet ejecting method) to form (image) a predetermined pattern, and for manufacturing an organic EL display device or a color filter for a liquid crystal display device, or for forming metal wiring lines on a substrate. The material of the substrate W is not particularly limited, and the substrate may include any plate-shaped member, such as a glass substrate, a silicon substrate, a flexible substrate, etc.

A work piece in the present invention is not limited to the plate-shaped member, and may include any member having a flat bottom surface. For example, the present invention can be applied to a liquid droplet ejecting apparatus, etc., for forming a coating film, such as an optical thin film, by using a lens as a work piece and ejecting liquid droplets to the lens. The present invention can be applied particularly preferably to a relatively large liquid droplet ejecting apparatus1which can cope with a relatively large work piece (for example, a work piece having a length and a width ranging from several tens of centimeters to several meters).

The liquid droplet ejecting apparatus1comprises a main body2, a substrate carrying table (a substrate carrying stage)3as a work piece mounting unit, a head unit11having a plurality of droplet ejecting heads (ink-jet heads)111, an accessory apparatus (a maintenance apparatus)12provided at the side of the main body2, a tank housing unit13, a blow unit14for emitting a gas to a substrate W, a length-measuring laser unit15for measuring the moved length of the substrate carrying table3, and a dot-omission detecting unit19.

The ejection liquid to be ejected from the droplet ejecting heads111is not particularly limited, and may include liquid (including a dispersed liquid, such as a suspension, an emulsion, etc.) containing, for example, the following various materials in addition to an ink containing filter materials for a color filter: a light-emitting material for forming an EL light-emitting layer in an organic EL (electroluminescence) device; a fluorescent material for forming a fluorescent layer on an electrode in an electron-emitting device; a fluorescent material for forming a fluorescent layer in a PDP (Plasma Display Panel) device; an electrophoretic material for forming an electrophoretic layer in an electrophoresis display device; a bank material for forming a bank on a surface of a substrate W; various kinds of coating materials; a liquid-state electrode material for forming an electrode; a particle material for forming a spacer for forming a fine cell gap between two sheets of substrates; a liquid-state metal material for forming a metal wire; a lens material for forming a micro lens; a resist material; and a light-diffusing material for forming a light diffusing layer.

As shown inFIG. 2, the main body2has a trestle21provided on the floor and a stone surface plate (a surface plate)22provided on the trestle21. The substrate-carrying table3is provided on the stone surface plate22to be movable in the Y-axis direction with respect to the main body2. The substrate-carrying table3advances and retreats in the Y-axis direction by means of driving of a linear motor51.

The substrate W is mounted on the substrate-carrying table3.

The liquid droplet ejecting apparatus1may use substrates W having various sizes and shapes, including substrates ranging from a relatively large substrate W, having the same size as the substrate-carrying table3, to a relatively small substrate W that is smaller than the substrate-carrying table3. It is generally preferable that the liquid droplet ejecting operation be performed in a state where the centers of the substrate W and the substrate-carrying table3are aligned, but, in a case of the relatively small substrates W, the liquid droplet ejecting operation may be performed in a state where the substrates are positioned close to the edge portions of the substrate-carrying table3.

As shown inFIG. 1, in the vicinities of the two sides along the X-axis direction of the substrate-carrying table3, a before-imaging flushing unit104for receiving liquid droplets wastefully ejected (also referred to as preliminarily ejected or flushed) from the droplet ejecting heads111before the ejection of liquid droplets (imaging) to the substrate W is provided. A suction tube (not shown) is connected to the before-imaging flushing unit104, and the wastefully ejected liquid is recovered and stored through the suction tube by a liquid discharging unit18to be described later.

The moved length of the substrate-carrying table3in the Y-axis direction is measured by the length-measuring laser unit15as a moved length detecting means. The length-measuring laser unit15has a length-measuring laser sensor head151, a mirror152, and a length-measuring laser unit body153provided on the main body2side, and a corner cube154provided on the substrate-carrying table3side. Laser rays emitted from the length-measuring laser sensor head151along the X axis are bent by the mirror152, advance in the Y-axis direction, and are irradiated to the corner cube154. The reflected ray from the corner cube154returns to the length-measuring laser sensor head151via the mirror152. In the liquid droplet ejecting apparatus1, based on the moved length (the current position) of the substrate-carrying table3detected by the length-measuring laser unit15, the ejection timing from the droplet ejecting heads111is generated.

A main carriage61supporting the head unit11is provided in the main body2to be movable in the X-axis direction in a space above the substrate-carrying table3. The head unit11, having a plurality of droplet ejecting heads111, advances and retreats in the X-axis direction, together with the main carriage61by way of driving a linear motor actuator62comprising a linear motor and a guide.

In a so-called primary scanning of the droplet ejecting heads111in the liquid droplet ejecting apparatus1according to the present embodiment, the droplet ejecting heads111are driven (the liquid droplets are selectively ejected) on the basis of the ejection timing generated using the length-measuring laser unit15, while moving the substrate-carrying table3in the Y-axis direction. Correspondingly thereto, a so-called secondary scanning is performed by means of the movement of the head unit11(the droplet ejecting heads111) in the X-axis direction.

A blow unit14for semi-drying the liquid droplets ejected to the substrate W is provided in the main body2. The blow unit14has a nozzle opened in a slit shape along the X-axis direction, and emits gas to the substrate W from the nozzle while carrying the substrate W in the Y-axis direction by means of the substrate-carrying table3. In the liquid droplet ejecting apparatus1according to this embodiment, two blow units14positioned at positions separated from each other in the Y-axis direction are provided.

In the vicinity of the main body2and the accessory apparatus12, a tank housing unit13having a rack131is provided. As shown inFIG. 9, a first primary tank (an ejection liquid tank)401, a second primary tank (an ejection liquid tank)402, a first cleaning solution tank501, a second cleaning solution tank502, a first reuse tank171, a second reuse tank172, a first discharged liquid tank181, and a second discharged liquid tank182are provided (housed) on the rack131of the tank housing unit13. (The first discharged liquid tank181and the second discharged liquid tank182are not shown inFIG. 9). Further, although two primary tanks are provided in this embodiment, one primary tank or three or more primary tanks may be provided (the same is also true of other tanks).

The first primary tank401and the second primary tank402store the ejection liquid to be ejected from the droplet ejecting heads111. The first cleaning solution tank501and the second cleaning solution tank502store the cleaning solution to be supplied to a cleaning unit81that will be described later. The first reuse tank171and the second reuse tank also172store the ejection liquid to be recovered from a capping unit83that will be described later. The first discharged liquid tank181and the second discharged liquid tank182store the ejection liquid ejected from the droplet ejecting heads111in the before-imaging flushing unit104, a regular flushing unit82that will be described later, and a dot-omission detecting unit19that will also be described later.

The first primary tank401and the second primary tank402can be filled up with the ejection liquid or can be replaced with a full tank when they are empty. That is, any one of the replacement (detachment or attachment) or fill-up of the ejection liquid may be performed on the first primary tank401and the second primary tank402.

Similarly, the first cleaning solution tank501and the second cleaning solution tank502may also be subjected to replacement or fill-up. The first reuse tank171, the second reuse tank172, the first discharged liquid tank181, and the second discharged liquid tank182, respectively, may be subjected to replacement with empty tanks, or extraction of the inner liquid when they are full.

As shown inFIG. 1, the dot-omission detecting unit19is fixed to a position which is not superposed with the moving area of the substrate-carrying table3on the stone surface plate22; and which is below the moving area of the head unit11. The dot-omission detecting unit19performs a dot-omission inspection (an ejection confirming inspection) for inspecting (detecting) a dot-omission resulting from the clogging of an ejecting nozzle of the droplet ejecting head111. The dot-omission detecting unit19comprises, for example, a light-emitting portion and a light-receiving portion for emitting and receiving a laser ray and a dot-omission inspecting liquid receiver.

When the dot-omission inspection is performed, the liquid droplets are ejected from respective ejecting nozzles of the droplet ejecting heads111while the head unit11moves in the X-axis direction in a space above the dot-omission detecting unit19. The dot-omission detecting unit19performs the light-emitting and light-receiving process on the ejected liquid droplets to optically detect the clogging of the ejecting nozzles and their positions. Liquid (liquid droplet) ejected from the droplet ejecting head111in the dot-omission inspection is received by the dot-omission inspecting liquid receiver.

A suction tube (not shown) is connected to the bottom of the dot-omission inspecting liquid receiver, and the liquid received by the dot-omission inspecting liquid receiver is restored by a liquid discharging unit18, which will be described later, through the suction tube, and stored in the first discharged liquid tank181and the second discharged liquid tank182.

The dot-omission inspection employing the dot-omission detecting unit19can be performed by, for example, a method described in Japanese Unexamined Patent Application Publication No. 2002-192740, but it is not limited to the method and may be performed by other methods.

In the vicinity of the liquid droplet ejecting apparatus1, a control unit (control means)16is provided. The control unit16controls all of the elements of the liquid droplet ejecting apparatus1and has a CPU (Central Processing Unit) and a memory unit for storing various programs, such as programs for executing the control operation of the liquid droplet ejecting apparatus1, and various data. In the illustrated configuration, the control unit16is provided outside the chamber91that will be described later.

The liquid droplet ejecting apparatus1preferably performs the ejection of liquid droplets (imaging) on the substrate W in an atmosphere in which the temperature and humidity are managed by a chamber unit9. The chamber unit9has a chamber91for housing the liquid droplet ejecting apparatus1and an air-conditioning system92provided outside the chamber91. The air conditioning system92has a known air-conditioner therein and adjusts the temperature and humidity of air, and transfers the adjusted air to a space911under the roof of the chamber91through an inlet duct93. The air transferred to the space911under the roof from the air-conditioning system92passes through a filter912provided below the roof, and goes into the main room913of the chamber91.

In the chamber91, an auxiliary room916, in addition to the main room913, is provided by means of partition walls914and915, and the tank housing unit13is provided in the auxiliary room916. A communicating portion (a passage)917for communication of the main room913with the auxiliary room916is formed in the partition wall914.

The auxiliary room916is provided with an opening and closing door (an opening and closing portion)918to the outside of the chamber91(seeFIG. 1). The opening and closing portion of the auxiliary room916is not limited to a hinged door, such as the opening and closing door918, and may be a sliding door, a shutter, etc.

A discharging outlet for discharging gas in the auxiliary room916is formed in the auxiliary room916, and an outlet duct94extending outwardly is connected to the discharging outlet. The air in the main room913flows into the auxiliary room916through the communicating portion917, and is then discharged to the outside of the chamber unit9through the outlet duct94.

Since the temperature and humidity around the liquid droplet ejecting apparatus1are managed by means of the chamber unit9, it is possible to prevent errors resulting from the expansion and contraction of the elements or the substrate W due to a variation in temperature, and thus to image (form) the pattern with high accuracy on the substrate W with the liquid droplets. Further, since the tank housing unit13is also placed in an environment in which the temperature and humidity are managed, a characteristic, such as viscosity of the ejection liquid, is stabilized so that it is possible to form (image) a pattern with high accuracy with the liquid droplets. Since the infiltration of dust, etc., into the chamber91can be prevented, it is possible to keep the substrate W clean.

The inside of the chamber91is supplied and filled with a gas other than air (for example, an inert gas, such as nitrogen, carbon dioxide, helium, neon, argon, krypton, xenon, radon, etc.) by way of conditioning the gas, and then, in the atmosphere of the chosen gas, the liquid droplet ejecting apparatus1may be operated.

In the liquid droplet ejecting system10, the tank housing unit13can be accessed without exposing the main room913to the outside by opening the opening and closing door918. As a result, since the managed temperature and humidity around the liquid droplet ejecting apparatus1are not disturbed in accessing the tank housing unit13, it is possible to form (image) a pattern with high accuracy, even immediately after performing a replacement of the tanks, a fill-up, or recovery of the liquid. Since it is not necessary to wait until the temperature in the main room913or the temperatures of the elements of the liquid droplet ejecting apparatus1are restored to a managed value after performing a replacement of the tanks, a fill-up, or recovery of the liquid, it is possible to enhance throughput (production efficiency). As a result, it is very advantageous for mass-producing work pieces, such as substrates W, with high accuracy, and thus it is possible to reduce the manufacturing cost.

FIG. 3is a plan view illustrating the trestle, the stone surface plate, and the substrate-carrying table in the liquid droplet ejecting apparatus shown inFIGS. 1 and 2; andFIG. 4is a side view illustrating the trestle, the stone surface plate, and the substrate-carrying table in the liquid droplet ejecting apparatus shown inFIGS. 1 and 2.

As shown inFIGS. 3 and 4, the substrate-carrying table3and the Y-axis movement mechanism5for moving the substrate-carrying table3in the Y-axis direction are provided on the stone surface plate22. As shown inFIG. 3, a plurality of suction holes (suctioning portions)332for suctioning and fixing the mounted substrate W are formed in the substrate-carrying table3.

As shown inFIG. 4, the Y-axis movement mechanism5has a linear motor51and an air slider52. The air slider52has a slide guide521extending in the Y-axis direction on the stone surface plate22and a slide block522movable along the slide guide521. The slide block522has an air-emitting port for emitting air between the slide block and the slide guide521, and can be smoothly moved by interposing the air emitted from the air-emitting port between the slide block522and the slide guide521.

A base108is fixed onto the slide block522, and the substrate-carrying table3is fixed onto the base108with a θ axial rotation mechanism105therebetween. In this way, the substrate-carrying table3is supported by the air slider52to be smoothly movable in the Y-axis direction, and can be moved in the Y-axis direction by means of operating the linear motor51. The substrate-carrying table3is rotatable within a predetermined range about the vertical θ axis passing through the center of the substrate carrying table3by means of the θ axial rotation mechanism105.

Above the Y-axis movement mechanism5, a pair of band-shaped thin plates101made of a metal material, such as stainless steel, are provided to cover the Y-axis movement mechanism5. The thin plates101pass through a concave portion (groove) formed in the upper surface of the base108, and are inserted between the base108and the θ axial rotation mechanism105. The ejection liquid ejected from the droplet ejecting heads111can be prevented from being attached to the Y-axis movement mechanism5by providing the thin plates101, thereby protecting the Y-axis movement mechanism5.

The stone surface plate22is formed out of immaculate stone, and its upper surface has high flatness. The stone surface plate22is excellent in various characteristics, such as stability against a variation in an environmental temperature, an attenuation characteristic against vibration, stability against secular variation (deterioration), and corrosion resistance against the ejection liquid. In this embodiment, by allowing the substrate-carrying table3, the Y-axis movement mechanism5, and the X-axis movement mechanism6, which will be described later, to be supported by the stone surface plate22, errors due to variation in environmental temperature, vibration and secular variation (deterioration) are small. As such, the relative movement of the substrate-carrying table3and the head unit11(the droplet ejecting heads111) can be performed with high accuracy, and the high accuracy can be stably maintained. As a result, it is possible to form (image) a pattern from the liquid droplets with higher accuracy and with stability. The stone material forming the stone surface plate22is not particularly limited, and may preferably be one of Belfast Black, Rustenberg, Kurnool, and Indian Black. Accordingly, the aforementioned characteristics of the stone surface plate22can be improved.

The stone surface plate22is supported by the trestle21. The trestle21has a frame211formed of a square shape out of an angle, etc., and a plurality of support legs212distributed and arranged under the frame211. Preferably, the trestle21has a vibration-proof structure employing an air spring or a rubber bush, so that vibration from the floor can be prevented from being transferred to the stone surface plate22.

The stone surface plate22is preferably supported by (mounted on) the trestle21in a state not coupled (not fixed) to the trestle21. As a result, it is possible to avoid the influence of heat expansion, etc., generated in the trestle21on the stone surface plate22, so that it is possible to form (image) a pattern with the liquid droplets with higher accuracy.

In this embodiment, as seen two-dimensionally, the stone surface plate22comprises a Y-axis movement mechanism support221having a longitudinal rectangular shape in the Y-axis direction, and pillar supports222and223protruding toward both sides in the X-axis direction from middle portions of the longitudinal sides of the Y-axis movement mechanism support221. As a result, the stone surface plate22has a cross shape as seen two-dimensionally. In other words, the stone surface plate22has a shape obtained by removing the four corner portions from a rectangular shape, as seen two-dimensionally. On the pillar supports222and223, four pillars23that will be described later are provided. That is, the stone surface plate22has a shape obtained by removing portions not formed with the Y-axis movement mechanism5and the pillars23from a rectangular shape, as seen two-dimensionally.

As a result, since the weight of the stone surface plate22decreased and the area occupied with the stone surface plate22can be reduced, it is possible to facilitate transfer of the liquid droplet ejecting apparatus1to an installing place thereof, to reduce the load resistance of the floor in the installing place of a plant, and to decrease the area occupied with the liquid droplet ejecting system10in the plant. The stone surface plate22according to this embodiment may be made of one stone piece, or may be formed by combining a plurality of stone pieces.

FIG. 5is a plan view illustrating the head unit and the X-axis movement mechanism in the liquid droplet ejecting apparatus shown inFIGS. 1 and 2,FIG. 6is a side view as seen from an arrow A inFIG. 5, andFIG. 7is a front view as seen from an arrow B inFIG. 5.

As shown inFIGS. 6 and 7, the total of four pillars23, of which two pillars are opposite to two pillars through the Y-axis movement mechanism5, and two parallel bars24and25extending in the X-axis direction and supported by the pillars23are provided on the stone surface plate22(the pillar supports222and223). The substrate-carrying table3can pass below the bars24and25.

The X-axis movement mechanism6for moving the droplet ejecting heads111(the head unit11) in the X-axis direction is supported through the bars24and25by the four pillars23. As shown inFIG. 5, the X-axis movement mechanism6has a main carriage (a head unit support)61for supporting the head unit11, a linear motor actuator62that is provided on the bar24and guides and drives the main carriage61in the X-axis direction, and a guide63that is provided on the bar25and guides the main carriage61in the X-axis direction. The main carriage61is laid over the linear motor actuator62and the guide63.

In this embodiment, the Y-axis movement mechanism5and the X-axis movement mechanism6constitute a relative movement mechanism for relatively moving the substrate-carrying table3and the droplet ejecting heads111(the head unit11).

The head unit11is detachably supported by the main carriage61. By moving the head unit11together with the main carriage61in the X-axis direction, the secondary scanning of the droplet ejecting heads111is performed. The head unit11is supported by the main carriage61through a head unit height adjusting mechanism20for adjusting the height of the head unit11from the main carriage61. As a result, in accordance with the thickness of the substrate W, a gap between the nozzle-formed surfaces of the droplet ejecting heads111and the substrate W can be adjusted.

As shown inFIG. 7, the linear motor actuator62and the guide63extend outwardly over the pillars23. Accordingly, the head unit11can be moved over the accessory apparatus12that will be described later.

A camera carriage106is laid over the linear motor actuator62and the guide63. The camera carriage106shares the linear motor actuator62and the guide63with the main carriage61, and is moved in the X-axis direction independently from the main carriage61.

A recognition camera107for recognizing images of alignment marks formed at predetermined places on the substrate W is provided in the camera carriage106. The recognition camera107is suspended downwardly from the camera carriage106. The recognition camera107may be used for another purpose.

FIG. 8is a schematic view illustrating a pattern-forming operation (an imaging operation) in the liquid droplet ejecting apparatus shown inFIGS. 1 and 2. As shown inFIG. 8, the head unit11is provided with a plurality of droplet ejecting heads111(twelve in this embodiment). In the nozzle-formed surface of each droplet ejecting head111, a plurality of ejecting nozzles (holes) for ejecting the liquid droplets are formed to be arranged in one or more lines. In the head unit11, the twelve droplet ejecting heads111are arranged in the second scanning direction (the X-axis direction) to form two lines in which six droplet ejecting heads are arranged on every line, and the nozzle lines of the droplet ejecting heads111are positioned obliquely about the secondary scanning direction.

Each ejecting nozzle of the droplet ejecting heads111is provided with a driving part having a piezoelectric element as a driving element (not shown). The control unit16controls the driving parts of the droplet ejecting heads111via a driver (not shown). Accordingly, in the droplet ejecting heads111, the liquid droplets are ejected from predetermined ejecting nozzles of predetermined droplet ejecting heads111. In this case, for example, when a predetermined voltage is applied to a piezoelectric element, the piezoelectric element is deformed (expanded or contracted) to apply pressure to a corresponding pressure room (a liquid room), so that the predetermined amount of liquid droplets is ejected from the corresponding ejecting nozzle (an ejecting nozzle communicating with the above pressure room).

In the present invention, the droplet ejecting heads111are not limited to the aforementioned configuration, and may have, for example, a configuration in which the liquid to be heated are heated and boiled by means of a heater as a driving element and then the liquid droplets are ejected from the ejecting nozzle by means of its pressure.

The aforementioned arrangement pattern of the droplet ejecting heads111in the head unit11is only an example, and the droplet ejecting heads111adjacent to each other in each line of heads may be arranged to form an angle of 90° (that is, the adjacent heads form a truncated chevron shape), or the droplet ejecting heads111may be arranged such that the heads between the lines of heads form an angle of 90° (that is, the inter-line heads form a truncated chevron shape). At any rate, the dots of the overall ejecting nozzles of the plural droplet ejecting heads111should be continuous in the secondary scanning direction.

Further, the droplet ejecting heads111may not be positioned obliquely about the secondary scanning direction, but, instead, the plurality of droplet ejecting heads111may be arranged in a zigzag shape, a step shape, etc. Furthermore, as long as a nozzle line (a dot line) having a predetermined length can be formed, the arrangement may have a single droplet ejecting head111. Furthermore, the main carriage61may be provided with a plurality of head units11.

Next, the entire operation of the liquid droplet ejecting apparatus1controlled by the control unit16will be briefly described. When the substrate W is supplied onto the substrate-carrying table3and is positioned (pre-alignment) at a predetermined position on the substrate-carrying table3by means of a substrate positioning unit (not described) provided in the liquid droplet ejecting apparatus1, the substrate W is suctioned and fixed to the substrate-carrying table3via air suction from the suction holes332of the substrate-carrying table3. Next, the recognition camera107is moved over the alignment marks formed at a predetermined position (one or more positions) of the substrate W by means of movement of the substrate-carrying table3and the camera carriage106, and then recognizes the alignment marks. On the basis of a recognition result, the θ axial rotation mechanism105is actuated to correct a θ axial rotation angle of the substrate W, and correction of positions of the substrate W in the X-axis direction and the Y-axis direction is performed (main alignment) on the data.

After the alignment process on the substrate W is completed, the liquid droplet ejecting apparatus1starts the process of forming (imaging) a predetermined pattern on the substrate W. This process is carried out by performing the primary scanning and secondary scanning of the droplet ejecting heads111(the head unit11) on the substrate W.

In the liquid droplet ejecting apparatus1according to this embodiment, the primary scanning is performed by ejecting the liquid droplets from the droplet ejecting heads111onto the substrate W while moving the substrate W in the Y-axis direction by means of the movement of the substrate-carrying table3, in a state where the head unit11is fixed (not moved relatively) to the main body2. That is, the Y-axis direction is the primary scanning direction in this embodiment.

Primary scanning may be performed during advance (forward movement) of the substrate-carrying table3, during retreat (backward movement) of the substrate-carrying table, and during both of advance and retreat (reciprocating movement) of the substrate-carrying table. Further, primary scanning may be performed several times by reciprocating the substrate-carrying table3several times. Through the primary scanning, the ejection of liquid droplets onto an area of the substrate W extending in the primary scanning direction with a predetermined width (a width which can be covered with the head unit11) is completed.

After the primary scanning, secondary scanning is performed. While liquid droplets are not being ejected, secondary scanning is performed by moving the head unit11by a predetermined width in the X-axis direction through movement of the main carriage61. That is, in this embodiment, the X-axis direction is the secondary scanning direction.

After secondary scanning, primary scanning, described above, is performed again. Accordingly, the liquid droplets are ejected to an area adjacent to the area in which the liquid droplets are ejected through previous primary scanning.

In this way, by repeatedly and alternately performing the primary scanning and the secondary scanning, the liquid droplets are ejected to the entire area of the substrate W, so that it is possible to form (image) a predetermined pattern of the ejected liquid droplets (liquid) on the substrate W.

In the present invention, the primary scanning direction and the secondary scanning direction may be inverted. That is, primary scanning may be performed by ejecting the liquid droplets to the substrate W while moving the droplet ejecting head111(head unit11) in the X-axis direction in a state where the substrate W (the substrate-carrying table3) is fixed, and secondary scanning may be performed by moving the substrate W (the substrate-carrying table3) in the Y-axis direction during non-ejection of the liquid droplets.

FIGS. 10 and 11are a perspective view and a side view illustrating the accessory apparatus of the liquid droplet ejecting apparatus shown inFIGS. 1 and 2, respectively; andFIGS. 19 and 20are plan views illustrating the liquid droplet ejecting apparatus shown inFIGS. 1 and 2. Now, with reference to these figures, the accessory apparatus12of the liquid droplet ejecting apparatus1will be described.

The head unit11waits at a position above the accessory apparatus12, for example, during the supply and removal of the substrate W. In the course of the wait, the cleaning process or the capping process on the nozzle-formed surfaces of the droplet ejecting heads111is performed, or the regular wastefully ejection process (the regular flushing process) is performed.

The accessory apparatus12is provided at a side portion (the front side in the X-axis direction with respect to the main body2) of the trestle21and the stone surface plate22of the main body2. As shown inFIG. 10, the accessory apparatus12has an accessory stand85provided on the floor, a movable platen86which can be moved in the Y-axis direction on the accessory stand85, a cleaning unit (a cleaner for the droplet ejecting heads)81, a regular flushing unit82, a capping unit83, and an ejection-amount measuring unit (a weight measuring unit)84.

The cleaning unit81, the regular flushing unit82, the capping unit83, and the ejection-amount measuring unit84(hereinafter referred to as ‘four kinds of droplet ejecting head maintenance units’) are one of the droplet ejecting head maintenance units used for function maintenance, function recovery, adjustment and inspection of the droplet ejecting heads111, respectively. In the liquid droplet ejecting apparatus1according to the present invention, the four kinds of droplet ejecting head maintenance units are arranged in a group on the movable platen86as a maintenance-unit installing section (a maintenance-unit installing area).

As a result of this configuration, the liquid droplet ejecting apparatus1has high spatial efficiency with respect to the arrangement of the droplet ejecting head maintenance units, and the entire space of the liquid droplet ejecting apparatus1can be effectively utilized so that the installation space (the occupied area) required for installing the liquid droplet ejecting apparatus1in a plant can be reduced. In addition, since the four kinds of droplet ejecting head maintenance units are arranged in a group close to each other, the relative movement of the droplet ejecting head maintenance units and the head unit11can be rapidly performed. Thus, unnecessary movement is minimal when the head unit11sequentially uses the droplet ejecting head maintenance units. Therefore, the cycle time required for processing one sheet of the substrates W can be lessened so that it is possible to enhance throughput (the production efficiency). The respective droplet ejecting head maintenance units will be described later.

The accessory stand85of the accessory apparatus12has a longitudinal shape in the Y-axis direction, and the upper portion (the top surface) thereof is provided with a maintenance-unit moving mechanism854. The maintenance-unit moving mechanism854has a pair of guides (rails)851for guiding the movable platen86in the Y-axis direction, a ball screw852, and a motor853for rotating the ball screw852, so that the movable platen86can be moved (advanced or retreated) in the Y-axis direction.

As shown inFIG. 11, the movable platen86has a top end861, a bottom end862, a hoisting mechanism (a height adjusting mechanism)863using a ball screw, and a hoisting handle864. The top end861can go up and down with respect to the bottom end862by means of the hoisting mechanism863, and the height of the top end861can be adjusted by driving the hoisting handle864to operate the hoisting mechanism863. The hoisting mechanism863is not limited to the manual operation, and may be operated automatically by providing a driving source such as a motor.

On the top end861of the movable platen86, the cleaning unit81, the regular flushing unit82, the capping unit83, and the ejection-amount measuring unit84are arranged in a line along the Y-axis direction. Therefore, when the head unit11is placed above the accessory apparatus12by moving the movable platen86in the Y-axis direction, one of the four kinds of droplet ejecting head maintenance units can be selectively placed below the head unit11, and maintenance by the selected droplet ejecting head maintenance unit can be performed on the head unit.

For example, in a state where the movable platen86is placed at a position shown inFIG. 1, since the capping unit83is placed below the droplet ejecting heads111of the head unit11when the head unit11is moved above the accessory apparatus12, the capping process can be performed. In a state where the movable platen86is placed at a position as shown inFIG. 19, since a roller unit160(a roller76) of the cleaning unit81is placed below the droplet ejecting heads111of the head unit11when the head unit11is moved above the accessory apparatus12, the cleaning process can be performed on the nozzle-formed surfaces of the droplet ejecting heads111. Similarly, the wasteful ejection by the regular flushing unit82or ejection of liquid droplets by the ejection-amount measuring unit84can be performed.

In this way, in this embodiment, since the four kinds of droplet ejecting head maintenance units can be arranged in a line along the Y-axis direction by providing the maintenance-unit moving mechanism854, the side space of the main body2can be more effectively utilized, so that it is possible to shorten the entire X-axis length of the liquid droplet ejecting apparatus1.

In this embodiment, the droplet ejecting heads111can be replaced by detaching and attaching the droplet ejecting heads111from the main carriage61for each head unit11. In replacing the droplet ejecting heads111(the head unit11), as shown inFIG. 20, the maintenance-unit moving mechanism854moves the movable platen86to the rightmost end inFIG. 20, and then moves the head unit11above the accessory apparatus12. Accordingly, since the droplet ejecting heads111(the head unit11), detached and attached, and the four kinds of droplet ejecting head maintenance units on the movable platen86do not interfere with each other, it is possible to replace the droplet ejecting heads111(the head unit11) easily, rapidly and smoothly.

In this embodiment, when the height of the droplet ejecting heads111(the head unit11) is varied correspondingly to the thickness of the substrate W by means of the head unit height adjusting mechanism20, the height of the respective droplet ejecting head maintenance units provided on the top end861can be adjusted by means of the hoisting mechanism863in accordance with the height variation, so that it is possible to easily cope with the height variation of the droplet ejecting heads111accompanying with the thickness variation of the substrate W to be manufactured. Height adjustment (height fitting) of the droplet ejecting head maintenance units and the droplet ejecting heads111may be performed via up and down movements of the head unit11by means of the head unit height adjusting mechanism20.

In this embodiment, the movable platen86as the maintenance-unit installing section is supported by the accessory stand85that is physically separated from the main body2. Accordingly, since the vibration generated from the droplet ejecting head maintenance units on the movable platen86or the maintenance-unit moving mechanism854can be prevented from being transferred to the main body2, it is possible to avoid an adverse effect on the accuracy of the pattern to be formed (imaged) on the substrate W.

Further, since the size of the stone surface plate22can be greatly reduced, as compared with a case in which the four droplet ejecting head maintenance units (the movable platen86) are provided on the stone surface plate22, it is possible to reduce the cost for the expensive stone surface plate22and to reduce the entire weight of the liquid droplet ejecting apparatus1. Furthermore, since positional accuracy required for the four droplet ejecting head maintenance units provided on the movable platen86is relatively low, accuracy problems are avoided even if the droplet ejecting head maintenance units are not provided on the stone surface plate22.

Now, the four droplet ejecting head maintenance units provided in a group on the top end861of the movable platen86will be sequentially described.

FIG. 14is a perspective view illustrating the roller unit of the cleaning unit of the accessory apparatus shown inFIGS. 10 and 11.

The cleaning unit81wipes and cleans, regularly or occasionally, the respective nozzle-formed surfaces of the droplet ejecting heads111with a wiping sheet75.

The wiping sheet75has a feature that enable it to suction liquid. Further, its material is not particularly limited, and for example, woven cloth made of polyester can be suitably used.

As shown inFIGS. 10 and 11, the cleaning unit81has a wiping sheet supply unit150and a roller unit160. The wiping sheet supply unit150comprises a wind-off roller78for winding off and supplying the wiping sheet75, a take-up roller79for taking up the wiping sheet75after wiping the nozzle-formed surfaces, and an electric motor for rotating the take-up roller79.

As shown inFIG. 14, the roller unit160has a cylindrical roller76for pressing the wiping sheet75wound off from the wind-off roller78on the nozzle-formed surfaces. The roller76is rotatably supported by a roller casing161. At least the outer circumferential portion of the roller76is preferably made of an elastic material, such as rubber, etc., and thus has repulsive elasticity against the pressing force on the outer circumferential surface (pressing surface). The roller76is rotated in synchronism with the supply speed of the wiping sheet75supplied from the wiping sheet supply unit150. Here, the rotation of the roller76is performed by means of an electric motor163via a pulley76ccoaxially attached to the end portion of the rotary axis76aof the roller76and a belt162.

According to this cleaning unit81, a new cleaning surface of the wiping sheet75can be endlessly supplied to the nozzle-formed surfaces of the droplet ejecting heads111. Further, since the wiping sheet75is pressed on the nozzle-formed surfaces by means of the pressing force of the roller76, it is possible to ensure that the cleaning surface is brought into contact with the nozzle-formed surfaces.

In the vicinity of the roller76, a nozzle unit164having a plurality of nozzles (twelve nozzles in the shown configuration) for spraying the cleaning solution onto the wiping sheet75before wiping the nozzle-formed surfaces is provided. The nozzle unit164is a rod-shaped member in which a plurality of nozzles are perforated downwardly, and is provided parallel to an axial line (a rotary axis) of the roller76. The wiping sheet75wound off from the wind-off roller78passes under the nozzle unit164, under the guidance of the guide roller, not shown, to reach the roller76. The nozzle unit164sprays the cleaning solution onto the wiping sheet75passing under the nozzle unit through the nozzles from the surface side (the top surface). According to this configuration, the wiping sheet75before wiping the nozzle-formed surfaces can suction the cleaning solution, so that the wiping sheet75can be wet.

The cleaning solution is not particularly limited, and may include, for example, various cleaning agents or organic solvents. Unlike the shown configuration, the nozzle unit164may spray the cleaning solution from the back surface (the bottom surface) side of the wiping sheet75.

The respective nozzles formed in the nozzle unit164do not communicate with each other, but are independent from each other. The nozzle unit164is provided with piping connectors166corresponding to the respective nozzles, and the respective connectors166are connected to branching tubules41for supplying the cleaning solution to the corresponding nozzles. The branching tubules41are formed out of flexible tubes. The respective nozzles are supplied with a cleaning solution through the respective branching tubules41by means of a cleaning solution supply unit50that will be described later. InFIG. 14, for the purpose of simplification, only three of the twelve branching tubules41are shown.

Since the ejection liquid attached to the nozzle-formed surfaces of the droplet ejecting heads111can be wiped out regularly or occasionally by means of the cleaning unit81, disturbance is prevented from occurring in the ejecting direction (the flying direction) of the liquid droplets from the droplet ejecting nozzles, and thus the liquid droplets can be straightly sprayed, so that it is possible to form (image) a pattern with high accuracy on the substrate W.

In the cleaning unit81, the outer circumferential portion of the roller76may be divided plurally in the rotation axial direction of the roller76, and the outer circumferential surfaces (the pressing surfaces) of the divided portions may press the wiping sheet75against the droplet ejecting heads111. In this configuration, since the adjacent pressing surfaces do not interfere with each other in a state where the wiping sheet75is pressed against the nozzle-formed surfaces of the droplet ejecting heads111, it is possible to more accurately ensure that the wiping sheet75presses against the overall droplet ejecting heads111.

As shown inFIG. 10, the regular flushing unit82has liquid receivers821for receiving the liquid droplets wastefully ejected from the droplet ejecting heads111. The head unit11wastefully ejects the liquid droplets from the droplet ejecting heads111to the liquid receivers821regularly or occasionally during the waiting time. This operation is performed for the following purposes.

In general, if a large period of time elapses from the pause of the ejection of the liquid droplets to the restart of ejection of the liquid droplets by the droplet ejecting heads111, the ejecting direction of the liquid droplets is disturbed, possibly resulting in an amount of ejection that is either too large or too small, and thereby risking the possibility of an unstable droplet ejecting operation. That is, since the ejecting condition is not stable immediately after the droplet ejecting heads111begin the ejecting process, it is difficult for the liquid droplets to eject properly, and the amount of ejection is therefore not stable. For this reason, by performing the wasteful ejection to the liquid receivers821during the waiting time, a state in which the droplet ejecting head111can properly eject the liquid droplets is maintained.

The liquid receivers821are preferably provided with liquid absorbers formed of, for example, a sponge. Liquid droplets ejected wastefully to the liquid receivers821are first absorbed by the liquid absorber. Accordingly, it is possible to more accurately ensure that wastefully ejected liquid droplets do not fly in all directions. The liquid receivers821are connected to suction tubes (not shown), and ejection liquid gathered in the liquid receivers821is recovered through the suction tubes, and recovered and stored by means of the liquid discharging unit18that will be described later.

FIG. 15is a perspective view illustrating the capping unit of the accessory apparatus shown inFIGS. 10 and 11,FIG. 16is a cross-sectional view illustrating a state in which caps come into contact with the droplet ejecting heads, andFIG. 17is an absorption piping system diagram including respective caps in the capping unit.

Now, the capping unit83and the absorption piping system thereof will be described with reference to the above figures.

As shown inFIG. 15, the capping unit83has a base plate831and twelve caps87arranged on the base plate831. The respective twelve caps87correspond to the twelve droplet ejecting heads111mounted on the head unit11, and are arranged in the same arrangement pattern as are the droplet ejecting heads111. Accordingly, the respective caps87can come into (close) contact with and cover the nozzle-formed surfaces of the corresponding droplet ejecting heads111.

The capping unit83has a supporting portion832fixed on the movable platen86, and the base plate831is supported by the supporting portion832.

The supporting portion832is provided with a hoisting mechanism833employing a pneumatic cylinder for allowing the base plate831to go up and down. The caps87can go up and down in a group by means of the hoisting mechanism833.

When the respective droplet ejecting heads111of the head unit11are capped with the respective caps87, the respective caps87are first allowed to be in a down state, and if the head unit11is placed above the capping unit83, the respective caps87are allowed to go up and are brought into (close) contact with the respective droplet ejecting heads111. In this state, by activating suction pumps601,602, and603that will be described later, a fluid (gas and liquid) can be suctioned and discharged from the ejecting nozzles of the droplet ejecting heads111.

The process of bringing the caps87into contact with the droplet ejecting heads111and suctioning the fluid therefrom (hereinafter, referred to as the ‘capping and suctioning operation’) is performed regularly or occasionally for the following purposes:(1) to prevent the nozzle-formed surfaces of the droplet ejecting heads111from drying out when the head unit11is in a wait state (during the supply or removal of the substrate W);(2) to prevent the clogging of the nozzles of the droplet ejecting heads111in order to recover an ejection ready state;(3) to fill the droplet ejecting heads111and flow paths with the ejection liquid during an initial filling of the ejection liquid;(4) to discharge the ejection liquid from the droplet ejecting heads111and the flow paths during replacement of the ejection liquid with a different kind of liquid; and(5) to allow the cleaning solution to flow in the droplet ejecting heads111and the flow paths during a state in which the cleaning solution has been supplied to the droplet ejecting heads111, when cleaning the droplet ejecting heads111and the flow paths before replacement of the ejection liquid.

As shown inFIG. 16, each cap87has a cap body871and a cap holder872, and the cap body871is biased upwardly by means of two coil springs873, and is held by the cap holder872to be movable up and down in a predetermined range. A concave portion874capable of containing a nozzle group formed in one of the droplet ejecting heads111is formed on the top surface of the cap body871, and the edge portion of the concave portion874is provided with a seal packing (a seal member)875capable of coming in close contact with the droplet ejecting head111.

The bottom of the concave portion874is provided with a liquid absorber876formed of, for example, a sponge capable of absorbing liquid during the state in which the liquid absorber is pressed downward by a frame-shaped pressing member877. Further, an outlet878for discharging the fluid suctioned from the droplet ejecting head111is formed in the bottom of the concave portion874, and the outlet878communicates with an L-shaped joint879. The L-shaped joint879is connected to a pipe (a tube), not shown, constituting a suction flow path882that will be described later.

The respective caps87are provided with an opening valve880, and the opening valve can be opened from the bottom side of the concave portion874to the outside. The opening valve880is biased into a closed state by means of a coil spring881, and at the final step of the capping and suctioning operation, the liquid contained in the liquid absorber876can be suctioned by opening the opening valve880.

As shown inFIG. 11, the bottom end862of the movable platen86is provided with three suction pumps (suctioning force generating source)601,602, and603as suctioning force generating means for generating a suctioning force (negative pressure) in the respective caps87(on the insides of the caps87). In this embodiment, although the suction pumps601,602, and603comprise piston pumps, respectively, another type of pump or ejector (vacuum ejectors), etc., may be used as the suctioning force generating source.

The twelve caps87of the capping unit83are classified into three groups, each of which includes four caps. That is, the four caps87placed at the upper position inFIG. 15constitute a first group701, the four caps87placed at the vertically middle position inFIG. 15constitute a second group702, and the four caps87placed at the lower position inFIG. 15constitute the third group703. As shown inFIG. 17, the suction pumps601,602, and603correspond to the first group701, the second group702, and the third group703, respectively.

The caps87are connected to the suction flow paths882, respectively, and the suction flow paths882converge and are connected to the inlets of the corresponding suction pumps601,602, and603, respectively.

In the middle of the respective suction flow paths882, switching valves (flow path switching means)883capable of cutting off the corresponding flow paths are provided. The switching valves883can be automatically switched by means of actuators under the control of the control unit16.

Furthermore, in the middle of the respective suction flow paths882, pressure sensors (pressure detecting means)884for detecting pressure in the corresponding flow paths are provided. Detection results of the pressure sensors884are input into the control unit16, and on the basis of the detection results, suction errors, etc., in the respective caps87can be detected and notified, or operation of the suction pumps can be controlled.

In the capping and suctioning operation, in a state in which by switching the respective switching valves883of the first group701, the second group702, and the third group703, the suction flow paths882from the caps87, other than one cap87selected from the groups, are cut off, the suction from the selected one cap87is performed. While switching the switching valves883, the sequential suction from the four caps87of each group is performed.

The pipes connected to the respective discharging outlets of suction pumps601,602, and603are merged to form one discharging flow path885that is connected to a three-way valve (flow path switching means)886. The downstream side of the three-way valve886is divided into a discharging flow path176and a discharging flow path887; the discharging flow path176is connected to a three-way valve (flow path switching means)175, and the discharging flow path887is connected to a waste liquid tank (a waste liquid storage unit)888. The three-way valve886and the three-way valve175are automatically switched by means of actuators under the control of the control unit16.

As described above, when the droplet ejecting heads111and the flow paths are cleaned, a cleaning solution is supplied to the droplet ejecting heads111of the head unit11from a cleaning solution supply means, not shown, to perform the capping and suctioning operation (the aforementioned (5)). At this time, the three-way valve886is switched to a state in which a flow is formed from the discharging flow path885to the discharging flow path887, and the cleaning solution discharged from the droplet ejecting heads111is introduced into and stored in the waste liquid tank888.

On the contrary, in the capping and suctioning operation (the aforementioned (1) through (4)) in a normal state in which ejection liquid is supplied to the droplet ejecting heads111of the head unit11, the three-way valve886is switched to a state in which a flow is formed from the discharging flow path885to the discharging flow path176, and the ejection liquid discharged from the respective droplet ejecting heads111flows toward the three-way valve175.

The downstream side of the three-way valve175is divided into an introducing flow path173and an introducing flow path174; the introducing flow path173is connected to a first reuse tank171, and the introducing flow path174is connected to a second reuse tank172. The first reuse tank171and the second reuse tank172are provided in the tank housing unit13as described above.

The ejection liquid flowing from the discharging flow path176is introduced into and stored in the first reuse tank171and the second reuse tank172by means of switching of the three-way valve175.

In this embodiment, the first reuse tank171, the second reuse tank172, the introducing flow path173, the introducing flow path174, the three-way valve175, the discharging flow path176, the discharging flow path885, the three-way valve886, the discharging flow path887, and the waste liquid tank888described above constitute a liquid recovering unit (liquid recovering means)17.

In this way, the liquid recovering unit17transfers the ejection liquid discharged from the respective droplet ejecting heads11in the capping and suctioning operation, and stores the ejection liquid in the first reuse tank171and the second reuse tank172, exclusive, without mixing it with different liquid (for example, the ejection liquid obtained from the before-imaging flushing unit104, the regular flushing unit82and the dot-omission detecting unit19, or the cleaning solution used for cleaning the droplet ejecting heads111and the flow paths).

Since ejection liquid recovered into the first reuse tank171and the second reuse tank172is not exposed to the outside and is not in contact with the outside atmosphere until the ejection liquid is first discharged from the droplet ejecting heads111and is finally transferred to the first reuse tank171or the second reuse tank172, only a minimal amount of foreign materials, such as refuse, etc., if any, are mixed thereto, and a solvent is never vaporized to change the concentration thereof. Further, since different liquids are not mixed thereto as described above, the ejection liquid lies in a good condition without a change in quality due to deterioration or the mixing of foreign materials. Therefore, the ejection liquid recovered into the first reuse tank171and the second reuse tank172can be supplied again to the first primary tank401and the second primary tank402, and can be reused as ejection liquid to be ejected from the droplet ejecting heads111. As a result, since the unnecessary amount of consumption of the ejection liquid can be greatly reduced, it is possible to reduce the manufacturing cost for the substrate W.

It is preferable that before reusing the ejection liquid recovered into the first reuse tank171and the second reuse tank172(before restoring the ejection liquid to the first primary tank401and the second primary tank402), the ejection liquid be subjected to a process of removing impurities therefrom (for example, a filtering process using a filter) or a de-aerating process of removing gas dissolved therein (for example, a process of sparkling the dissolved gas under a reduced pressure condition). As a result, the recovered ejection liquid to be reused will be in better condition.

Since the liquid recovering unit17according to this embodiment uses both the first reuse tank171and the second reuse tank172while switching between them, the entire capacity can be increased, and it is thus possible to effectively cope with an increase in the amount of suction at the time of capping following a growth in size of the liquid droplet ejecting apparatus1. Since the entire capacity can be increased without excessively increasing individual capacities of the first reuse tank171and the second reuse tank172, excessive weights (specifically, weights when they are full) of the first reuse tank171and the second reuse tank172can be avoided, so that it is possible to reduce the burden of an operator when replacing the tanks. By alternately replacing (recovering) the first reuse tank171and the second reuse tank172, it is possible to recover ejection liquid without stopping the operation of the liquid droplet ejecting apparatus1. Therefore, production efficiency (throughput) can be enhanced.

FIG. 13is a diagram schematically illustrating a configuration of the liquid amount detecting means. As shown inFIG. 13(b), the liquid recovering unit17further includes liquid amount detecting means177afor detecting the amount of liquid in the first reuse tank171. The liquid amount detecting means177aincludes an optically transparent tube178, of which the inner cavity communicates with the inside of the first reuse tank171and which is provided vertically outside of the first reuse tank171, and a light-emitting portion179and a light-receiving portion170facing each other with the tube178therebetween in the vicinity of the top of the first reuse tank171. When the amount of liquid in the first reuse tank171is increased by means of the variation of the amount of light received by the light-receiving portion170to reach a predetermined upper limit level F (full), the liquid amount detecting means177acan detect it. The detection result of the liquid amount detecting means177ais input into the control unit16. The liquid recovering unit17further comprises liquid amount detecting means177bsimilar to the liquid amount detecting means177a, for detecting the amount of liquid in the second reuse tank172.

In the liquid recovering unit17, the ejection liquid suctioned from the capping unit83is introduced into the first reuse tank171in a state as shown inFIG. 17. Then, when the ejection liquid accumulates in the first reuse tank171and the liquid amount detecting means177adetects that the first reuse tank171is full, the control unit16switches the three-way valve175in accordance with the detection result into a state in which the ejection liquid is introduced into the second reuse tank172.

It is preferable that when the first reuse tank171and the second reuse tank-172are full, the control unit16notify the operator to replace the tank (to recover the ejection liquid), for example, similarly to the above description.

Although two reuse tanks are provided in the liquid recovering unit17according to this embodiment as described above, the present invention may provide a single reuse tank or three or more reuse tanks.

FIG. 18is a perspective view illustrating the ejection-amount measuring unit of the accessory apparatus shown inFIGS. 10 and 11.

The ejection-amount measuring unit84is used for measuring the amount of ejection of the liquid droplets (the amount of one droplet) of the droplet ejecting heads111as a preliminary step before ejecting the liquid droplets to the substrate W (before forming a pattern). In the liquid droplet ejecting system10, after the amount of liquid droplets ejected from each droplet ejecting head111is measured in advance and the amount of liquid droplets ejected from the respective droplet ejecting heads111is adjusted to a proper value (a predetermined value) in accordance with the measuring result, the ejection operation is performed on the substrate W. Accordingly, it is possible to form (image) a pattern with high accuracy.

The timing for performing the measurement and adjustment of the amount of liquid droplets ejected from the droplet ejecting heads111is not limited, and may occur when the liquid droplet ejecting system10is first activated or when the kind of the ejection liquid is changed. In addition, the measurement and adjustment of the amount of liquid droplets to be ejected may be performed regularly, and may be performed in a substrate unit before the liquid droplets are ejected to the substrate W.

As shown inFIG. 18, the ejection-amount measuring unit84comprises a plurality of ejection-amount measuring liquid receivers (ejection-amount measuring tray)841(as many as the droplet ejecting heads) corresponding to the respective droplet ejecting heads111of the head unit11, a plate-shaped support842for supporting the ejection-amount measuring liquid receivers841in a group, and a base843fixed to the movable platen86to hold the support842.

The ejection-amount measuring liquid receivers841receive the liquid droplets ejected from the droplet ejecting heads-111and hold (store) the received liquid. The respective ejection-amount measuring liquid receivers841are detachable to the support842. In the top surface of the support842, concave portions844into which the bottoms of the ejection-amount measuring liquid receivers842are inserted, respectively, are formed, and thus the ejection-amount measuring liquid receivers842can be positioned and supported in the same arrangement as the droplet ejecting heads111.

The support842is fixed to the base843by means of two thumbscrews845as fixing members to be detachable thereto. Accordingly, since the twelve ejection-amount measuring liquid receivers841can be detached and attached in a group for each support842, it is possible to easily and rapidly perform the detaching and attaching operation.

When measuring the amount of liquid droplets ejected from the droplet ejecting heads111, the droplet ejecting heads111are driven such that the head unit11is positioned above the ejection-amount measuring unit84, and then the liquid droplets are allowed to be ejected from the ejecting nozzles to the corresponding ejection-amount measuring liquid receivers841. At this time, the number of liquid droplets ejected from each ejecting nozzle is predetermined and is normally about 1 through 100,000, and more preferably about 25,000 through 50,000, but the number is not limited thereto.

In this embodiment, the process of measuring the amount of liquid droplets ejected from a droplet ejecting head111is performed by measuring the weight of all of the liquid (overall liquid droplets) received by the corresponding ejection-amount measuring liquid receiver841.

That is, the weights of the ejection-amount measuring liquid receiver841before and after receiving the liquid droplets are measured, and the difference between the two measurements is used as the weight of the overall liquid droplets received by the ejection-amount measuring liquid receiver841. Then, by dividing the measured weight by the number of liquid droplets received by the ejection-amount measuring liquid receiver841, the weight of one droplet ejected from each ejection nozzle is obtained.

When measuring the weight of an ejection-amount measuring liquid receiver841, the twelve ejection-amount measuring liquid receivers841are divided by the number of supports842, and are placed on a weight measuring unit (not shown) provided outside of the liquid droplet ejecting system10. The weight measuring unit comprises a scale, such as an electronic scale, and preferably automatically measures the weight of each ejection-amount measuring liquid receiver841. Alternatively, unlike the above construction, a scale may be provided in the ejection-amount measuring unit84to measure the weight of each ejection-amount measuring liquid receiver841by using the scale.

In this way, when the amount of liquid droplets ejected from the each droplet ejecting head111is measured, the amount of liquid droplets to be ejected from each droplet ejecting head111is adjusted based on the measured value. The adjustment of the amount of liquid droplets to be ejected from the droplet ejecting heads111can be performed by varying at least one of the amplitude, the frequency, or the driving waveform of an applied voltage (the pulse-shaped applied voltage) to the driving elements (piezoelectric elements) provided in the droplet ejecting heads111. Adjustment is performed by means of manipulation of a manipulation panel (not shown) of the control unit16.

After the amount of liquid droplets to be ejected from each droplet ejecting head111is adjusted, the amount of liquid droplets ejected from each droplet ejecting head111may be measured again to check whether the measured value is a proper value. In this way, in the liquid droplet ejecting apparatus1, by repeatedly performing the measurement and adjustment of the amount of liquid droplets ejected from the droplet ejecting heads111as needed, the amount of liquid droplets to be ejected from the droplet ejecting heads111is made to be appropriate.

In the liquid droplet ejecting system10, as described above, the operation of ejecting the liquid droplets onto the substrate W (the operation of forming a pattern) is performed in an atmosphere in which the temperature and humidity, as environmental conditions, are controlled. In general, the amount of liquid droplets ejected from the droplet ejecting heads111are varied in accordance with the environmental condition such as temperature, humidity, gaseous composition, gaseous pressure, etc., of the atmosphere, even if the driving conditions of the driving elements are the same. For this reason, even if the amount of liquid droplets ejected from the droplet ejecting heads111is measured, when the environmental conditions during the measurement differ from the environmental conditions during the actual ejecting of the liquid droplets onto the substrate W, the measured value generates an error with respect to the amount of liquid droplets ejected in ejecting the liquid droplets onto the substrate W. Therefore, even if the amount of liquid droplets to be ejected is made to be appropriate based on the measured value, improvement of the accuracy is limited.

In consideration of this problem, in the liquid droplet ejecting system10, when the liquid droplets are ejected to measure the amount of liquid droplets ejected from the droplet ejecting heads111, that is, when the liquid droplets are ejected to the ejection-amount measuring liquid receivers841, it is preferable that the ejection of liquid droplets be performed in an atmosphere in which the temperature and humidity (the environmental conditions) are controlled to be similar to the atmosphere in which the actual ejecting of the liquid droplets onto the substrate W occurs, by adjusting the temperature and humidity (the environmental conditions) in the chamber91.

As a result, in the liquid droplet ejecting system10, it is possible to more accurately perform measurement of the amount of liquid droplets without generating an error with respect to the amount of liquid droplets ejected in ejecting the liquid droplets onto the substrate W. Further, in the liquid droplet ejecting system10, by adjusting the amount of liquid droplets based on the accurately measured value to be appropriate, it is possible to accurately (with high accuracy) approach (adjust) the amount of liquid droplets when the liquid droplets are actually ejected onto the substrate W, and it is thus possible to form (image) a pattern on the substrate W with higher accuracy.

In this embodiment, the ejection-amount measuring liquid receivers841have liquid absorbers846such as sponges capable of absorbing the received liquid droplets (liquid) therein. As a result, since the ejection-amount measuring liquid receivers841can hold therein the liquid droplets received from the droplet ejecting heads111without allowing the liquid droplets to fly in all directions, it is possible to more accurately perform the measurement without generating a measurement error. Furthermore, since the received liquid is absorbed by the liquid absorbers846, the liquid is not spilled despite the shaking when the ejection-amount measuring liquid receivers841are detached and attached for measuring their weights, so that the handling is facilitated.

The ejection-amount measuring liquid receivers841are not limited to the above configuration, and may have a configuration such that a non-volatile liquid having a specific gravity less than that of the received ejection liquid is placed therein in advance and the liquid droplets are received in the non-volatile liquid.

In this embodiment, the base843has a height adjusting mechanism for adjusting the height of the support842with a screw. As a result, the height of the ejection-amount measuring liquid receivers841can be adjusted. By appropriately adjusting the distance between the droplet ejecting heads111and the ejection-amount measuring liquid receivers841using the height adjusting mechanism, it is possible to more accurately ensure that the liquid droplets do not fly in all directions.

The height adjusting mechanism of the ejection-amount measuring liquid receivers841may be constructed to automatically adjust the height by means of, for example, a pneumatic cylinder.

FIG. 12is a piping system diagram illustrating the ejection liquid supply unit, the cleaning solution supply unit, and the liquid discharging unit in the liquid droplet ejecting apparatus shown inFIGS. 1 and 2; andFIG. 13is a diagram schematically illustrating the configuration of the liquid amount detecting means. Now, the ejection liquid supply unit4, the cleaning solution supply unit50, and the liquid discharging unit18in the liquid droplet ejecting apparatus1will be described with reference to those figures and toFIG. 6.

First, the ejection liquid supply unit4for supplying the ejection liquid to be ejected from the droplet ejecting heads111will be described.

As shown inFIG. 12, the ejection liquid supply unit4comprises a primary tank system40for storing ejection liquid and one primary flow path411for connecting the primary tank system40to a secondary tank412that will be described later. The primary tank system40has a first primary tank401and a second primary tank402provided in the tank housing unit13, an outflow pipe403connected to the first primary tank401, an outflow pipe404connected to the second primary tank402, and a three-way valve (flow path switching means)405. The three-way valve405is connected to the primary flow path411and the outflow pipes403and404. The ejection liquid supply unit4can selectively supply the ejection liquid from either the first primary tank401or the second primary tank402to the primary flow path411by switching the three-way valve405.

The ejection liquid supply unit4further includes pressurizing means406for supplying pressurized gas to the first primary tank401and the second primary tank402, pressurizing pipes407and408connected to the first primary tank401to the second primary tank402, respectively, a pipe410from the pressurizing means406, and a three-way valve (pressure path switching means)409connected to the above three pipes. As the pressurizing means406, a pressurized gas source for supplying gas, such as pressurized nitrogen gas, etc., is used (pressurizing means506, described later, is similar thereto). The ejection liquid supply unit4can selectively pressurize the inside of either the first primary tank401or the second primary tank402using the pressurizing means406, by switching the three-way valve409.

As shown inFIG. 6, the secondary tank412is fixedly provided in the main carriage102. That is, the secondary tank412is moved in the X-axis direction, together with the main carriage102. The secondary tank412is connected to the other end of the first flow path411extending from the three-way valve405, and the ejection liquid of the primary tank system40flows into the secondary tank412through the first flow path411.

The first flow path411is formed preferably out of a flexible tube. The middle portion of the first flow path411is provided with a relay unit413for relaying the primary flow path411such that a portion of the secondary tank412side of the primary flow path411is movable correspondingly to the movement of the secondary tank412, being moved together with the main carriage102.

The secondary tank412and the head unit11are connected to each other through twelve secondary flow paths414corresponding to the twelve droplet ejecting heads111provided in the head unit11. That is, the head unit11is provided with the twelve inlets (connection holes)112corresponding to the respective droplet ejecting heads111, and the other ends of the twelve secondary flow paths414extending from the secondary tank412are connected to the inlets112, respectively. InFIG. 6, for the purpose of simplification, only two of the twelve secondary flow paths414are shown. Although the secondary flow paths414are formed of flexible tubes in the shown configuration, the secondary flow paths are not limited thereto, and may be formed of hard tubes.

The pressure of the secondary tank412is controlled by a pressure control unit (a negative pressure control unit), not shown, to be negative. The ejection liquid whose pressure is controlled in the secondary tank412is supplied to the respective droplet ejecting heads111through the respective secondary flow paths414. As a result, the pressure of the ejection liquid to be supplied to the respective droplet ejecting heads111is controlled, so that a good ejecting condition of liquid droplets in the nozzles of the droplet ejecting heads111can be obtained.

Respective middle portions of the secondary flow paths414are provided with cut-off valves415for cutting off the respective flow paths. The cut-off valves415cut off the secondary flow paths414when the pressure control unit does not work due to any cause, so that the ejection liquid flows continuously into the droplet ejecting heads111at a position lower than that of the secondary tank412from the secondary tank412, thereby preventing the ejection liquid from leaking from the droplet ejecting heads111.

As shown inFIG. 13(a), the ejection liquid supply unit4further includes liquid amount detecting means416for detecting the amount of liquid in the first primary tank401. The liquid amount detecting means416includes an optically transparent tube417, of which the inner cavity communicates with the inside of the first primary tank401and which is provided vertically outside the first primary tank401, and a light-emitting portion418and a light-receiving portion419facing each other with the tube417therebetween in the vicinity of the bottom of the first primary tank401.

When the amount of liquid in the first primary tank401is decreased by means of the variation of the amount of received light in the light receiving portion419to reach a predetermined lower limit level E (empty), the liquid amount detecting means416can detect it. The detection result of the liquid amount detecting means416is input into the control unit16.

The ejection liquid supply unit4includes a similar liquid amount detecting means420for detecting the amount of liquid in the second primary tank402. When the amount of liquid in the second primary tank402is decreased to reach a predetermined lower limit E, the liquid amount detecting means420detects it and inputs the detection result thereof to the control unit16.

In the ejection liquid supply unit4in the state shown inFIG. 12, the first primary tank401is pressurized by means of the pressurizing means406, and the ejection liquid in the first primary tank401is discharged through the outflow pipe403and the primary flow path411by means of the pressure, and supplied to the droplet ejecting heads111.

When the ejection liquid in the first primary tank401is consumed and the liquid amount detecting means416detects that the first primary tank401is empty, the control unit16switches the three-way valve405and the three-way valve409, respectively, based on the detection result. Accordingly, the pressurizing means406pressurizes the second primary tank402, and the ejection liquid in the second primary tank402is discharged through the outflow pipe404and the primary flow path411by means of the pressure and is supplied to the droplet ejecting heads111.

In the course of supplying the ejection liquid from the second primary tank402, an operator separates the empty first primary tank401from the rack131, refills the first primary tank with the ejection liquid, and then restores the first primary tank to the rack131. Thereafter, when the liquid amount detecting means420detects that the second primary tank402is empty, the control unit16switches the three-way valve405and the three-way valve409, respectively, to allow the ejection liquid to be supplied from the first primary tank401. Then, in the course of supplying the ejection liquid from the first primary tank401, an operator separates the empty second primary tank402from the rack131and refills the second primary tank with the ejection liquid.

It is preferable that when the first primary tank401and the second primary tank402are empty, the control unit16notify the operator to replace the tank (to re-charge the ejection liquid). The method for notification may include, for example, a method of displaying characters or graphic symbols on a manipulation panel (not shown), or a method of emitting a sound or voice. It is also preferable that an operator be notified as to which primary tank is empty by providing different characters, graphic symbols, sounds, or voices that distinguish between the empty state of the first primary tank401and the second primary tank402.

As described above, since the ejection liquid supply unit4according to this embodiment uses both the first primary tank401and the second primary tank402while switching between them, the entire capacity can be increased, and it is thus possible to effectively cope with an increase in consumption of the ejection liquid following a growth in the size of the liquid droplet ejecting apparatus1. Since the entire capacity can be increased without excessively increasing individual capacities of the first primary tank401and the second primary tank402, excessive weights (specifically, weights when full) of the first primary tank401and the second primary tank402, respectively, can be avoided, so that it is possible to reduce the burden of an operator when replacing the tanks.

Next, the cleaning solution supply unit50used in the cleaning unit81will be described, but the same elements as found in the ejection liquid supply unit4will be not described. As shown inFIG. 12, the cleaning solution supply unit50includes a first cleaning solution tank501and a second cleaning solution tank502provided in the tank housing unit13, an outflow pipe503connected to the first cleaning solution tank501, an outflow pipe504connected to the second cleaning solution tank502, a three-way valve (flow path switching means)505to which the outflow pipes503and504and a liquid supply pipe511to the cleaning unit81are connected, respectively, pressurizing means506for supplying pressurized gas to the first cleaning solution tank501and the second primary tank502, a pressuring pipe507connected to the first cleaning solution tank501, a pressuring pipe508connected to the second cleaning solution tank502, a three-way valve (pressurizing path switching means)509to which the pressurizing pipes507and508and a pipe (path)510from the pressurizing means506are connected, respectively, and liquid amount detecting means (not shown) for detecting the remaining amount of solution in the first cleaning solution tank501and the second cleaning solution tank502. The downstream side of the liquid supply pipe511is divided into the respective branching tubules41connected to the nozzle unit164through a manifold, not shown.

Next, the liquid discharging unit18for recovering the discharged liquid (the ejection liquid) wastefully ejected from the droplet ejecting heads111in the before-imaging flushing unit104, the regular flushing unit82and the dot-omission detecting unit19will be described, but the same elements as found in the liquid recovering unit17, described later, will not be described.

As shown inFIG. 12, the liquid discharging unit18includes a first discharged liquid tank181and a second discharged liquid tank182(not shown inFIG. 9) provided in the tank housing unit13, an inflow pipe183connected to the first discharged liquid tank181, an inflow pipe184connected to the second discharged liquid tank182, and a three-way valve (flow path switching means)185.

The three-way valve185is connected to a liquid discharging pipe186into which suction tubes (not shown) from the before-imaging flushing unit104, the regular flushing unit82, and the dot-omission detecting unit19are merged, and the inflow pipes183and184, respectively. The first discharged liquid tank181and the second discharged liquid tank182are provided with liquid amount detecting means (not shown) similar to the liquid amount detecting means177a,177b, described later, respectively.

In this embodiment, by means of the liquid discharging unit18, the ejection liquid discharged from the before-imaging flushing unit104, the regular flushing unit82, and the dot-omission detecting unit19is recovered and stored in common. The ejection liquid recovered from the respective units is exposed once externally in the liquid receivers of the respective units, so that foreign materials (refuse) are mixed thereto, or the solvent is vaporized through contact with the external air to change the concentration thereof. Therefore, the ejection liquid is generally abolished. In this embodiment, since the liquid to be abolished is stored in the first discharged liquid tank181and the second discharged liquid tank182in common, the operation of abolishing the liquid is completed at the same time, thereby contributing to a reduction in labor of an operator.

FIGS. 21 and 22are perspective views illustrating the fixed sections provided at the side surface of the accessory stand and the relevant piping components provided therein in the accessory apparatus shown inFIGS. 10 and 11, respectively.

As shown inFIG. 10, the side surfaces of the accessory stand85are provided with fixed sections (side wall sections)855and856to which the relevant piping components are fixed. The fixed sections855and856comprise parts of plate-shaped covers857and858covering the side surfaces of the accessory stand85. The fixed sections855and856are placed at positions receding (recessed) inwardly from the total width (the total width in the X-axis direction) of the accessory stand85.

As shown inFIG. 21, the fixed section855is provided with a clean gas filter750, an air filter751, a mist separator752, a three-way valve (an air operated valve)753, a regulator754, a regulator755, a three-way valve (an air operated valve)756, a regulator757, etc., as the relevant piping components used for the liquid droplet ejecting apparatus1.

The air filter751and the mist separator752remove the foreign material and the liquid droplets contained in the pressurized gas (nitrogen) supplied from the pressurizing means406, respectively. The pressure of the pressurized gas passing through the air filter751and the mist separator752is adjusted by means of the regulator757, and the pressurized gas passes through the clean gas filter750and is supplied to the first primary tank401and the second primary tank402.

The pressurized gas supplied from the pressurizing means406can be supplied to a pressurized tank (not shown) for storing the cleaning solution for cleaning the droplet ejecting heads and a pressurized tank (not shown) for storing the cleaning solution for cleaning the flow paths, by switching the three-way valves753and756. The regulators754and755adjust the pressure of the pressurized gas supplied to the pressurized tank.

As shown inFIG. 22, the fixed section856is provided with manifold valves758and759, an air supply manifold760, a regulator for a liquid discharging process pump761, a nitrogen discharging manifold762, an air discharging manifold763, etc., as the relevant piping components used for the liquid droplet ejecting apparatus1.

The manifold valves758and759switch the three-way valves in the ejection liquid supply unit4, the cleaning solution supply unit50, a liquid discharging unit18, a liquid recovering unit17, etc., described above. The regulator for the liquid discharging process pump761adjusts the suctioning force of a process pump (not shown) provided in the liquid discharging unit18, for suctioning the discharged liquid. The air supply manifold760, the nitrogen discharging manifold762and the air discharging manifold763divide or merge the pneumatic flow paths for operating the aforementioned three-way valves or the pneumatic cylinders provided in the liquid droplet ejecting apparatus1.

In this embodiment, by fixing various relevant piping components to the fixed sections855and856placed at the positions receding inwardly from the total width of the accessory stand85, the relevant piping components are provided not to be protruded outwardly from the total width of the accessory stand85. Accordingly, when an operator works in the vicinity of the accessory stand85(during replacement of the head unit11, maintenance of the apparatus, etc.), it is possible to easily and smoothly perform maintenance without interfering with the relevant piping components.

In the liquid droplet ejecting apparatus1described above, the four kinds of droplet ejecting head maintenance units are arranged in a group on the movable platen86as the maintenance-unit installing section, but in the present invention, the dot-omission inspecting unit19that is a kind of droplet ejecting head maintenance unit may be further arranged in a group in the maintenance-unit installing section. The droplet ejecting head maintenance units are not limited to the five kinds described above, and may include other kinds of droplet ejecting head maintenance units (having other functions) only if they are used for the function maintenance, the function recovery, the adjustment or the inspection of the droplet ejecting heads111. Further, in the present invention, at least three of the plurality of droplet ejecting head maintenance units may be arranged in a group in the maintenance-unit installing section.

FIG. 23is a plan view schematically illustrating another embodiment of the liquid droplet ejecting apparatus according to the present invention. Now, another embodiment of the liquid droplet ejecting apparatus according to the present invention will be described with reference to the above figure, but only the differences from the aforementioned embodiment will be briefly described, and the same details will be not described.

In a liquid droplet ejecting apparatus1A shown inFIG. 23(a), the substrate-carrying table3is provided to be movable in the Y-axis direction, and the head unit11(the droplet ejecting heads111) is provided to be movable in the X-axis direction, similarly to the aforementioned embodiment. In a droplet ejecting head maintenance-unit installing section100positioned below the area in which the head unit11is moved, the dot-omission detecting unit19, the cleaning unit81, the regular flushing unit82, the capping unit83, and the ejection-amount measuring unit84are arranged in the X-axis line in a group. By moving the head unit11in the X-axis direction, the head unit11can be positioned above the droplet ejecting head maintenance units. In the liquid droplet ejecting apparatus1A, the maintenance-unit moving mechanism is not necessary, so that it is possible to simplify the structure thereof.

In a liquid droplet ejecting apparatus1B shown inFIG. 23(b), a substrate table (a work mounting unit)3′ is provided fixedly in the main body, and a head unit11′ (droplet ejecting heads111) is provided to be movable in the X-axis direction and the Y-axis direction, respectively. The liquid droplet ejecting apparatus1B can perform the primary scanning and the secondary scanning by moving the head unit11′ over the substrate table3′ in the Y-axis direction and the X-axis direction, respectively.

In the droplet ejecting head maintenance-unit installing section100in the vicinity of the substrate table3′, the dot-omission detecting unit19, the cleaning unit81, the regular flushing unit82, the capping unit83, and the ejection-amount measuring unit84are arranged in a group to be adjacent to each other. By moving the head unit11′ in the droplet ejecting head maintenance-unit installing section100in the X-axis direction and the Y-axis direction, the head unit11can be positioned above the respective droplet ejecting head maintenance units. In the liquid droplet ejecting apparatus1B, the maintenance-unit moving mechanism is not necessary, so that it is possible to simplify the structure thereof.

So far, the embodiments of the liquid droplet ejecting apparatus according to the present invention have been described, but the present invention is not limited to these embodiments. The respective elements constituting the liquid droplet ejecting apparatus may be replaced with any element having the same function. Further, any element may be added thereto.

The Y-axis movement mechanism and the X-axis movement mechanism may use, for example, a ball screw (a feed screw) instead of the linear motor.

Furthermore, in the liquid droplet ejecting apparatus according to the present invention, primary scanning and secondary scanning may be performed by fixing the head unit (droplet ejecting heads) to the main body and moving the work (work mounting unit) in the Y-axis direction and the X-axis direction, respectively. That is, it is enough that the liquid droplet ejecting apparatus according to the present invention comprises a relative movement mechanism for relatively moving the work mounting unit and the droplet ejecting heads.

An electro-optical device according to the present invention is manufactured using the liquid droplet ejecting apparatus according to the present invention described above. A specific example of the electro-optical device according to the present invention is not particularly limited, and may include, for example, a liquid crystal display device, an organic EL display device, etc.

Furthermore, a method of manufacturing an electro-optical device according to the present invention employs the liquid droplet ejecting apparatus according to the present invention. The method of manufacturing an electro-optical device according to the present invention can be applied, for example, to a method of manufacturing a liquid crystal display device. That is, by selectively ejecting a liquid containing filter materials for respective colors to a substrate by using the liquid droplet ejecting apparatus according to the present invention, a color filter in which a plurality of filter elements are arranged on the substrate can be manufactured, and the liquid crystal display device can be manufactured by using the color filter. In addition, the method of manufacturing an electro-optical device according to the present invention can be applied to a method of manufacturing, for example, an organic EL display device. That is, by selectively ejecting a liquid containing light-emitting materials for respective colors to a substrate by using the liquid droplet ejecting apparatus according to the present invention, an organic EL display device in which a plurality of pixels, including EL light-emitting layers, are arranged on the substrate can be manufactured.

Furthermore, an electronic apparatus according to the present invention comprises the electro-optical device manufactured in the aforementioned way. A specific example of the electronic apparatus according to the present invention is not particularly limited, and may include a personal computer, a mobile phone, etc., equipped with the liquid crystal display device or the organic EL display device manufactured in the aforementioned way.