JP2010214293A - Functional liquid tank, method of replacing functional liquid in droplet discharge device, and droplet discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional liquid tank capable of efficiently replacing an old functional liquid with new one, a method of replacing the functional liquid in a droplet discharge device and the droplet discharge device. <P>SOLUTION: The functional liquid tank receives the supply of the functional liquid from a functional liquid supply source and supplies the functional liquid to the functional droplet discharge head 17 of a ink jet system and includes a tank body having a liquid reservoir part 71 facing a flow out side port and formed to be recessed on the bottom part and a liquid reservoir liquid level detecting means facing the liquid reservoir part 71 to detect the liquid level of the functional liquid in the liquid reservoir part 71. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a functional liquid tank that receives functional liquid from a functional liquid supply source and supplies functional liquid to a functional liquid droplet ejection head, a functional liquid replacement method for the liquid droplet ejection apparatus, and a liquid droplet ejection apparatus.

  Conventionally, there is no functional liquid replacement method for a droplet discharge device, but there is a functional liquid filling method for a droplet discharge head that fills the flow path in the droplet discharge head with a combination of liquid feeding and suction. It is known (see Patent Document 1). This functional liquid filling method is mainly performed when the droplet discharge head is replaced, and compressed air is supplied to the sealed liquid supply sub-tank to send the functional liquid in the liquid supply sub-tank to the droplet discharge head. After the pressurized liquid feeding process to fill the flow path in the head of the droplet discharge head and the functional liquid, and the pressure liquid feeding process, the suction unit is driven to suck the functional liquid from the nozzle of the liquid droplet ejection head And a process. In this manner, by performing the filling operation by feeding the functional liquid to the droplet discharge head and the subsequent operation of sucking the functional liquid, initial filling is possible and bubbles remain in the flow path in the head. Is preventing.

JP 2004-188410 A

By the way, when a different functional liquid is to be introduced into the functional liquid supply device that supplies the functional liquid to the functional liquid droplet ejection head, according to the above-described conventional functional liquid filling method, the filling flow path of the functional liquid supply device at that time All the old functional liquid filled in the (all flow paths) is drained, and then the new functional liquid is filled using the above filling operation and suction operation. However, as a rule of thumb, it is known that once the functional liquid filled in all the channels is drained, the ejection characteristics of the functional liquid droplet ejection head after filling are deteriorated. Therefore, the functional liquid gradually replaces the functional liquid in the flow path by simultaneously sucking the functional liquid (old functional liquid) and filling the functional liquid (new functional liquid) to the extent that the sub tank is not emptied. A replacement method is conceivable.
On the other hand, the above-mentioned subtank is provided with an upper limit detection sensor for detecting the liquid level of the upper limit functional liquid and a lower limit detection sensor for detecting the lower limit of the functional liquid level. Functions by alternately repeating the extraction process that drains the liquid until the liquid level of the old functional liquid stored in the tank is sensed by the lower limit detection sensor and the liquid feeding process that feeds the new functional liquid into the sub tank. It is conceivable to replace the liquid. However, if this is done, the old functional liquid remaining below the lower limit detection sensor and the new functional liquid sent to the sub-tank are mixed in the sub-tank, and the mixed liquid spreads through the minute gaps in the sub-tank, so Even if the liquid process is repeated sufficiently, it cannot be completely removed, so a large amount of functional liquid is consumed before the inside of the sub tank is completely replaced with the new functional liquid, and the replacement efficiency is very high. There was a problem of getting worse.

  It is an object of the present invention to provide a functional liquid tank, a functional liquid replacement method for a droplet discharge device, and a droplet discharge device that can efficiently replace old and new functional liquids.

  The functional liquid tank of the present invention is a functional liquid tank that receives the functional liquid from a functional liquid supply source and supplies the functional liquid to the ink jet type functional liquid droplet ejection head. Further, the present invention is characterized by comprising: a tank body in which a liquid reservoir portion is recessed, and a liquid reservoir level detecting means that faces the liquid reservoir portion and detects the liquid level of the functional liquid in the liquid reservoir portion.

  According to this configuration, for example, when the functional liquid is removed from the functional liquid tank via the functional liquid droplet ejection head when the functional liquid tank and the functional liquid droplet ejection head are replaced, The liquid level of the functional liquid will drop. Here, when the liquid level of the reduced functional liquid reaches the liquid reservoir and is detected by the liquid pool level detection means, the suction operation is stopped. For this reason, the functional liquid tank and the subsequent flow paths and the functional liquid droplet ejection head are not completely emptied, that is, the functional liquid is left in the functional liquid tank and the liquid is drained once. Can do. In addition, since the functional liquid remaining in the functional liquid tank remains in the liquid reservoir portion that has been recessed and formed facing the outflow side port, the concentration of the new functional liquid was appropriately mixed and maintained at the subsequent introduction of the new functional liquid. It will not remain. Therefore, the mixing of the old functional liquid remaining in the functional liquid tank and the newly delivered new functional liquid can be suppressed to a small amount, and the replacement efficiency of the functional liquid can be increased.

  In this case, the liquid column pipe attached to the tank main body, the upper limit liquid level detecting means for detecting the upper limit liquid level of the functional liquid stored in the tank main body facing the liquid column pipe, and the lower limit liquid for detecting the lower limit liquid level It is preferable that the position detection means is further provided, and the liquid reservoir is disposed below the lower communication part of the liquid column pipe communicating with the tank body.

  According to this configuration, in the replacement operation of the functional liquid, when the functional liquid tank is filled with the functional liquid by the liquid supply after draining, the liquid supply is automatically stopped using the upper limit liquid level detecting means. Can do. That is, the functional liquid can be replaced efficiently by using the liquid pool liquid level detecting means and the upper limit liquid level detecting means. Moreover, the functional liquid in the liquid column pipe which is difficult to mix with the new functional liquid and easily remains can be completely removed.

  Moreover, it is preferable to further include a float that is accommodated in the tank body and floats and sinks with a minute gap on the inner wall of the tank body.

  According to this configuration, the float can suppress the fluctuation of the head value and promote the gas-liquid separation, while the functional liquid remains in the minute gap between the tank body and the float in the functional liquid replacement operation. It becomes easy. However, due to the recessed liquid reservoir, it is possible to completely extract the functional liquid with a minute gap that is difficult to mix with the new functional liquid and remains easily.

  The functional liquid replacement method of the droplet discharge device of the present invention includes the functional liquid tank, a functional liquid supply source that supplies the functional liquid to the functional liquid tank, and an inkjet function that receives the functional liquid from the functional liquid tank. A functional liquid replacement method for a liquid droplet ejection apparatus that replaces the functional liquid in all the channels from the functional liquid supply source to the functional liquid droplet ejection head with respect to a liquid droplet ejection apparatus having a liquid droplet ejection head. The functional liquid supply source is shifted from the old functional liquid to that of the new functional liquid while all the flow paths are filled with the functional liquid, and the functional liquid is sucked from the discharge nozzle of the functional liquid droplet discharge head, and the liquid pool liquid The extraction process of extracting the functional liquid from the functional liquid tank until the level detecting means detects the liquid level, and the sending of the functional liquid from the functional liquid supply source to the functional liquid tank until the upper limit liquid level detecting means detects the liquid level. Partial replacement process consisting of liquid process Repeat count function liquid characterized by old and new replacement.

  The liquid droplet ejection apparatus of the present invention is a liquid droplet ejection apparatus that replaces the old and new functional liquid in all the channels from the functional liquid supply source through the functional liquid tank to the ink jet type functional liquid droplet ejection head. The two main tanks serving as the functional liquid supply source for the new functional liquid and the functional liquid supply source for the old functional liquid, the flow path switching means for switching the tank flow paths of the two main tanks, the flow path switching means and the functional liquid The functional liquid channel connecting the droplet discharge head, the functional liquid tank provided in the functional liquid channel, and the functional liquid in each main tank are sent to the functional liquid tank via the functional liquid channel. A liquid feeding means, a suction means that comes in close contact with the nozzle surface of the functional liquid droplet ejection head, and sucks the functional liquid from the ejection nozzle of the functional liquid droplet ejection head, a channel switching means, a liquid feeding means, and a suction means Control means for controlling The means switches the flow path switching means, shifts the main tank from the old functional liquid to the new functional liquid, operates the suction means, and functions until the liquid level detection means detects the liquid level Extraction operation of the functional liquid from the liquid tank and partial replacement operation consisting of the liquid supply operation of supplying the functional liquid from the functional liquid supply source to the functional liquid tank until the upper limit liquid level detecting means detects the liquid level a predetermined number of times. It is characterized by repeatedly replacing the functional fluid with new and old ones.

  According to these configurations, when the extraction process (extraction operation) and the liquid supply process (liquid supply operation) with respect to the functional liquid tank are repeated, the old functional liquid that fills the entire flow path is gradually removed from the functional liquid droplet ejection head. On the other hand, the new functional liquid is sent from the functional liquid supply source to the functional liquid tank in contact with the old functional liquid. In the functional liquid tank, the interface disappears and the new functional liquid and the old functional liquid are mixed. However, the functional liquid tank is gradually replaced with the new functional liquid by repeating the partial replacement step (partial replacement operation). When the partial replacement process (partial replacement operation) is repeated a predetermined number of times, the old functional liquid becomes the new functional liquid not only in the functional liquid tank but also in the flow channel in the head of the functional liquid droplet ejection head. Substitution is performed up to a predetermined substitution rate (substitution rate corresponding to complete substitution). As described above, since the old functional liquid is drained and the new functional liquid is filled simultaneously, the replacement of the old and new functional liquid can be performed in a short time. Furthermore, the new function liquid can replace the old function liquid while in contact with or mixed with the old function liquid, and the new function liquid can be prevented from contacting air as much as possible when the new function liquid is filled. Therefore, it is possible to effectively prevent the deterioration of the new functional liquid due to air and the remaining of bubbles (air) in the functional liquid flow path. Also, in the extraction process (extraction operation), the functional liquid is extracted from the functional liquid tank until the liquid level detection means detects the liquid level. The functional liquid can be replaced efficiently without affecting the ejection characteristics of the droplet ejection head.

  In this case, it is preferable that the new and old functional liquids are drawing inks having different components, or the old and new functional liquids are drawing ink and cleaning liquid.

  According to this configuration, the new drawing ink is not in contact with the air without emptying the functional liquid tank even when the cleaning process is performed between the replacement of the new and old drawing ink as well as the replacement of the old and new drawing ink. It can be filled without.

It is a perspective view of the droplet discharge device concerning an embodiment. It is a plane model diagram of a head unit. It is an external appearance perspective view of a functional droplet discharge head. It is a piping system diagram of a functional liquid supply device. It is a side view of a suction unit. FIG. 4 is a cross-sectional view schematically showing the area around a sub tank. It is a simple piping system diagram of a functional fluid supply device. It is a flowchart of a functional liquid replacement method.

  Hereinafter, a droplet discharge device to which a functional liquid replacement method according to an embodiment of the present invention is applied will be described with reference to the accompanying drawings. This droplet discharge device is incorporated in a flat panel display production line, and uses, for example, a function droplet discharge head into which a special ink or a functional liquid that is a light-emitting resin liquid is introduced, and the color of a liquid crystal display device A light emitting element or the like to be used for each pixel of a filter or an organic EL device is formed.

  As shown in FIG. 1, a droplet discharge device 1 is disposed on an X-axis support base 2 supported by a stone surface plate, extends in the X-axis direction that is the main scanning direction, and moves a workpiece to an X-axis. And an X-axis table 11 that is moved in the direction and a pair of Y-axis support bases 3 that span across the X-axis table 11 via a plurality of columns 4 and that are in the sub-scanning direction. The Y-axis table 12 extending in the axial direction and the 13 carriage units 51 on which a plurality of functional liquid droplet ejection heads 17 (not shown in FIG. 1) are mounted. It is suspended from the Y-axis table 12. Further, the droplet discharge device 1 includes a chamber 6 that accommodates these devices in an atmosphere in which temperature and humidity are controlled, and a functional droplet discharge head 17 that passes through the chamber 6 from the outside of the chamber 6 to the inside. And a functional liquid supply unit 7 having three sets of functional liquid supply devices 101 (see FIG. 4) for supplying the functional liquid. The functional liquid droplet discharge head 17 is driven to discharge in synchronization with the driving of the X-axis table 11 and the Y-axis table 12, thereby discharging the R, G, B three-color functional liquid droplets supplied from the functional liquid supply unit 7. A predetermined drawing pattern is drawn on the work.

  The droplet discharge device 1 includes a maintenance device 5 including a flushing unit 8, a suction unit 9, a wiping unit 14, and a discharge performance inspection unit 18, and these units are used for maintenance of the functional droplet discharge head 17. The function of the functional liquid droplet ejection head 17 is maintained and recovered.

  The flushing unit 8 receives waste discharge (flushing) of the functional liquid droplet ejection head 17 that is performed immediately before the ejection of the functional liquid droplet ejection head 17 or when drawing processing is suspended such as when the work is replaced. The wiping unit 14 has a wiping sheet and wipes the nozzle surface 97 of the functional liquid droplet ejection head 17 after suction. The ejection performance inspection unit 18 recognizes an image of the functional liquid droplets ejected from the functional liquid droplet ejection head 17 and inspects the ejection performance (the presence or absence of ejection and the flight curve) of the functional liquid droplet ejection head 17. Although the details will be described later, the suction unit 9 has a plurality of divided suction units 9a, forcibly sucks the functional liquid from the discharge nozzles 98 of the respective functional liquid droplet discharge heads 17 and performs capping.

  Each carriage unit 51 includes a head unit 13 including twelve functional liquid droplet ejection heads 17 and a carriage plate 53 that supports the twelve functional liquid droplet ejection heads 17 in two groups. (See FIG. 2). Each carriage unit 51 is suspended from a bridge plate 52 that is stretched over a pair of Y-axis support bases 3. Each carriage unit 51 uses a natural water head from a sub tank (functional liquid tank) 121 disposed on the bridge plate 52, and the functional liquid is supplied to each functional liquid droplet ejection head 17 via the pressure adjustment valve 150. It has become so. The number of carriage units 51 and the number of functional liquid droplet ejection heads 17 mounted on each carriage unit 51 are arbitrary.

  As shown in FIG. 3, the functional liquid droplet ejection head 17 is a so-called double ink jet head, which is a functional liquid introducing portion 91 having two connecting needles 92 and 2 sideways connected to the side of the functional liquid introducing portion 91. A series of head substrates 93 and a head body 94 that is connected to the lower side of the head substrate 93 and filled with a functional liquid are provided. The connection needle 92 is connected to the functional liquid supply unit 7 and supplies the functional liquid to the functional liquid introduction unit 91. The head main body 94 includes a cavity 95 (piezoelectric piezoelectric element) and a nozzle plate 96 having a nozzle surface 97 in which a large number of discharge nozzles 98 are opened. When the functional droplet discharge head 17 is driven to discharge, functional droplets are discharged from the discharge nozzle 98 by the pump action of the cavity 95.

  As shown in FIG. 4, the functional liquid supply unit 7 includes three sets of functional liquid supply devices 101 corresponding to R, G, and B colors. The functional liquid supply unit 7 includes a nitrogen gas supply facility 85 that supplies compressed nitrogen gas for control to the main tank (functional liquid supply source) 181 and the sub tank (functional liquid tank) 121 and the like, and controls various on-off valves. A compressed air supply facility 86 for supplying compressed air, a gas exhaust facility 87 for exhausting gas from each part, and a bubble removing unit 135. The three sets of functional liquid supply devices 101 are connected to the functional liquid droplet ejection heads 17 corresponding to the R, G, and B colors, respectively. Liquid is supplied.

  Each functional liquid supply apparatus 101 includes a tank unit 122 having two main tanks 181 and 181 constituting a functional liquid supply source, 13 sub tanks 121 provided corresponding to each carriage unit 51, and a tank unit 122. And a functional liquid flow path 123 that connects each functional liquid droplet ejection head 17. The functional liquid in each main tank 181 is connected to this and pressurized by compressed nitrogen gas from the nitrogen gas supply equipment 85, and is selectively supplied to the 13 sub tanks 121 via the functional liquid flow path 123. . At that time, various open / close valves are controlled to open and close by the compressed air of the compressed air supply facility 86. At the same time, each sub tank 121 is opened to the atmosphere via the gas exhaust equipment 87 and receives a necessary amount of functional liquid. The functional liquid in each sub-tank 121 is supplied to the functional liquid droplet ejection head 17 via the functional liquid flow path 123 while maintaining a predetermined hydraulic head pressure by driving the functional liquid droplet ejection head 17 connected thereto. In addition, liquid feeding by a pump may be used in addition to liquid feeding by the above gas pressure.

  The tank unit 122 includes a pair of main tanks 181 and 181 serving as a functional liquid supply source, a pair of weight measuring devices 182 and 182 that respectively measure the weights of the pair of main tanks 181 and 181, and the functional liquid channel 123. And a switching mechanism (flow path switching means) 183 that switches the communication state from one main tank 181 to the other main tank 181. Each main tank 181 has a nitrogen gas supply facility 85 and a gas exhaust facility 87 in order to perform pressurization control for pressure-feeding the functional liquid and negative pressure control for back-feeding the function liquid (corresponding to release to the atmosphere). It is connected.

  The switching mechanism 183 includes a pair of tank passages 186 and 186 connected to the pair of main tanks 181 and 181, a pair of tank passages 186 and 186 connected to the upstream side, and a functional liquid passage 123 on the downstream side. Are connected to each other, and a tank opening / closing valve 188 interposed in each of the tank flow paths 186 and 186 is provided. By closing one tank on-off valve 188 and opening the other tank on-off valve 188, the connection to the functional liquid flow path 123 is alternately switched between the pair of main tanks 181 and 181. .

  The functional liquid flow path 123 is connected to the main functional liquid flow path 124 whose upstream end is connected to the tank unit 122 and the downstream end of the main functional liquid flow path 124, and is divided into 13 branches that divide the main functional liquid flow path 124 into 13 branches. The flow path 132, the 13 branch flow path 132, and the individual functional liquid flow path 127 that connects the respective functional liquid droplet ejection heads 17 are configured. The main functional liquid channel 124 is provided with a bubble removing unit 135 that removes microvalves in the functional liquid over time via a gas passage film.

  The individual functional liquid channel 127 includes a tank side channel 146 having an upstream end connected to the 13 branch channel 132, a head side channel 128 having an upstream side connected to the sub tank 121, and a head side channel 128 having an upstream side. The four branch flow paths 147 are connected to each other, and a plurality of individual flow paths 148 are connected to the four branch flow paths 147 on the upstream side. Thereby, the functional liquid branches from each sub tank 121 in four directions and is connected to the respective functional liquid droplet ejection heads 17. That is, the functional liquid is supplied to 13 × 4 functional liquid droplet ejection heads 17 by the 13 branches of the functional liquid flow path 123 and the 4 branches of the individual functional liquid flow path 127.

  As shown in FIG. 5, the suction unit 9 includes 13 cap units 31 in which 12 head caps 21 corresponding to 12 functional liquid droplet ejection heads 17 are arranged on a cap plate 22, and a support member 23. 13 elevating mechanisms 32 that elevate and lower each cap unit 31, 13 suction channel systems 27 (see FIG. 7) connected to each cap unit 31 and having a functional fluid suction channel, and each suction channel And a suction mechanism (not shown) having two waste liquid tanks connected to the system 27 and corresponding to two pressure levels. Although not shown, the suction unit 9 is connected to a compressed air supply facility that supplies compressed air for control to a pressure control mechanism and the like, an exhaust facility for exhausting air from each part, and a waste liquid tank. And a functional liquid waste liquid facility for draining the used functional liquid.

  The cap unit 31 includes a head cap 21 corresponding to a total of twelve functional liquid droplet ejection heads 17 for each color, and a cap plate 22 on which these are mounted. The lifting mechanism 32 includes a lifting cylinder 24 that lifts and lowers the head cap 21 directly via the support member 23, a pair of linear guides 25 that guides the lifting and lowering by the lifting cylinder 24, and a base portion 26 that supports these. ing.

  In the suction operation by the suction unit 9, the cap unit 31 is lifted by the elevating mechanism 32, the head cap 21 corresponding to each functional liquid droplet ejection head 17 is brought into close contact, and then the ejector 28 (see FIG. 7) is driven. The functional liquid is sucked from the discharge nozzle 98 of the functional liquid droplet discharge head 17.

  Here, with reference to FIG. 6, the sub tank (functional liquid tank) 121 which concerns on this embodiment is demonstrated in detail. The sub tank 121 includes a sub tank main body 171 for storing functional liquid, a lid float 172 dropped on the sub tank main body 171 and floated like a lid, a transparent liquid column pipe 176 disposed on the side of the sub tank main body 171, and a liquid column. A liquid level detecting mechanism 173 that faces the pipe 176 and detects the level of the stored functional liquid, and a liquid reservoir 71 provided at a position below the lower communication part 125 of the liquid column pipe 176 that communicates with the sub tank main body 171. And a liquid pool liquid level detection sensor (liquid pool liquid level detection means) 72 that faces the liquid pool section 71 and detects the liquid level of the functional liquid in the liquid pool section 71. Also, below the sub tank 121, an inflow joint (inflow side port) 163 connected to the tank side flow path 146 via the third on-off valve 139, and an outflow joint (outflow side) connected to the head side flow path 128 are provided. Port) 164 is provided. In this way, the functional liquid is configured to flow from below the sub tank main body 171 and flow out from below. Further, a nitrogen gas supply facility 85 and a gas exhaust facility 87 are connected to the upper portion of the sub tank main body 171 (see FIG. 4), and the inside of the sub tank main body 171 is opened to the atmosphere when liquid is supplied from the main tank 181. And it is comprised so that pressurization control to the main tank 181 is possible.

  The liquid level detection mechanism 173 faces the liquid column pipe 176, and is provided at an upper and lower intermediate position and an upper limit detection sensor (upper limit liquid level detection means) 178 that detects the liquid level of the upper limit functional liquid. A liquid level detection sensor 177 for detecting the liquid level of the functional liquid, and a lower limit detection sensor (lower limit liquid level detection means) 179 for detecting the liquid level of the lower limit functional liquid. The upper limit detection sensor 178 is provided to prevent the sub tank 121 from overflowing. When the upper limit detection sensor 178 detects the upper limit liquid level, the liquid supply from the main tank 181 is stopped. On the other hand, the lower limit detection sensor 179 is provided to prevent the sub-tank 121 from becoming empty. When the lower limit detection sensor 179 detects the lower limit liquid level, the liquid droplet is discharged when drawing of the current work is completed. Discharge device 1 is stopped.

  The liquid level detection sensor 177 detects the liquid level in consideration of the ideal water head value of the functional liquid droplet ejection head 17. When the liquid level detection sensor 177 detects the liquid level of the functional liquid, the control unit 102. It is judged that the liquid is full or reduced by cooperating with. That is, from the state where the liquid level is above the liquid level detection sensor 177, the functional liquid is reduced by the discharge operation, and the liquid level is detected by the liquid level detection sensor 177, so it is determined that the liquid level is low. Further, from the state where the liquid level is below the liquid level detection sensor 177, the functional liquid is increased by the replenishment operation, and after the liquid level is detected by the liquid level detection sensor 177, it is determined that the liquid is full. By such a liquid level detection sensor 177, the liquid level of the functional liquid in the sub tank 121 is controlled to the upper and lower intermediate position.

  Here, the replenishment operation of the functional liquid from the main tank 181 as the functional liquid supply source to the sub tank 121 will be described. When the functional liquid in the sub-tank 121 is reduced by a certain amount and the liquid level detection mechanism 173 determines that the liquid level is reduced, the third on-off valve 139 is opened and the gas exhaust equipment 87 is driven to operate the main tank. The functional liquid is supplied from the tank 181 to the sub tank 121. Since the main tank 181 is pressurized, the functional fluid in the main tank 181 is automatically sent to the sub tank 121 by opening the third on-off valve 139 and opening the atmosphere in the sub tank 121. When a certain amount of the functional liquid in the sub tank 121 is stored and the liquid level detection mechanism 173 determines that the sub tank 121 is full, the third on-off valve 139 is closed and the replenishment operation is terminated.

  On the other hand, as shown in FIG. 6, the liquid reservoir 71 communicates with the bottom of the sub-tank main body 171 and is formed in a recess, and has a circular or square shape. The functional liquid stored in the sub-tank main body 171 is configured to flow out through the outflow path 165 and the outflow joint 164 via the liquid reservoir 71. A liquid pool level detection sensor 72 is provided so as to detect the functional liquid in the liquid reservoir 71 so as to face the liquid reservoir 71. The liquid pool level sensor 72 is installed for the purpose of allowing the functional liquid to remain in the liquid reservoir 71 without being completely emptied, and is used in a functional liquid extraction process in a functional liquid replacement method described later. When the liquid level is detected by the liquid pool level sensor 72, the liquid draining operation in the functional liquid draining process is stopped in cooperation with the control unit 102. That is, the suction of the functional liquid from the sub tank 121 is stopped with a slight amount of the old functional liquid left in the liquid reservoir 71. Therefore, the old and new functional liquids can be efficiently replaced by leaving the minimum functional liquid without completely emptying the sub tank 121.

  Next, a functional liquid replacement method of the functional liquid supply apparatus 101 (functional liquid supply unit 7) will be described with reference to FIGS. In this functional liquid replacement method, a functional liquid (old functional liquid) filled in the functional liquid supply apparatus 101 (all flow paths) is extracted (incompletely extracted), and functional liquids having different components (new functional liquid) The extraction and filling are repeated. Needless to say, the functional liquid replacement sequence starts from the state in which the old functional liquid remains in one main tank 181 and the other main tank 181 filled with the new functional liquid is set. Then, a functional liquid is sucked from the discharge nozzle 98 of the functional liquid droplet discharge head 17 to extract a predetermined amount of the functional liquid from the sub tank 121 (S1 to S3), and the functional liquid is sent from the main tank 181 to the sub tank 121 by pressure. The liquid feeding step (S4 to S6) for liquid is repeated a predetermined number of times.

  First, the switching mechanism 183 switches the flow path from the old functional liquid main tank 181 currently used to the main tank 181 filled with the new functional liquid. Next, the suction unit 9 is driven, and the extraction process (S1 to S3) for draining the sub tank 121 is started. Specifically, the old functional liquid in the sub tank 121 is drained through the functional liquid droplet ejection head 17 until the liquid level detection sensor 72 in the first sub tank 121 detects liquid reduction. In this extraction step, the liquid level in the sub tank 121 is lowered to the position of the liquid pool liquid level detection sensor 72. For this reason, the lid float 172 of the sub tank 121 falls to the bottom of the sub tank 121, and the functional liquid in the gap between the sub tank 121 and the lid float 172 and the functional liquid in the liquid column pipe 176 can be removed. Become. In addition, in the functional liquid flow path 123 from the main tank 181 to the sub tank 121, a reverse feed pipe connected to the waste liquid tank is provided, so that the old functional liquid in the flow path is pushed out from the main tank 181. The functional liquid may be fed and the old functional liquid may be sent to the waste liquid tank through the reverse piping pipe.

  Next, the 3rd on-off valve 139 is opened, and the liquid feeding process (S4-S6) to the sub tank 121 is started. Specifically, the third on-off valve 139 is opened until the upper limit detection sensor 178 of the first sub tank 121 detects full liquid, and the first sub tank 121 is replenished with functional fluid. In this case, since the old functional liquid does not remain in a portion (micro gap) that is difficult to mix with the new functional liquid, such as the gap between the sub tank 121 and the lid float 172 or the liquid column pipe 176, the replacement rate is significantly improved. . In particular, even when the specific gravity of the new functional liquid is higher than that of the old functional liquid, a high replacement rate is maintained. Thereby, the first partial replacement process (S1 to S6) of the first sub tank 121 is completed. Subsequently, the partial replacement process for the second to thirteenth sub-tanks 121 is performed to complete the first partial replacement process. After the first partial replacement step, the second partial replacement step is performed on the first to thirteenth sub-tanks 121. Then, by repeating this partial replacement process a plurality of times (predetermined number of times), the functional liquid replacement of the entire flow path from the main tank 181 to the functional liquid droplet ejection head 17 is completed. The number of repetitions is the number of times that the functional liquid sucked from the functional liquid droplet ejection head 17 has a replacement rate (99.0%) corresponding to complete replacement. This number of repetitions is equal to the replacement rate. It is preferable to use the number of times determined in advance as a test.

  According to the above configuration, not only the draining of the old functional liquid and the filling of the new functional liquid are performed at the same time, but by providing the liquid reservoir 71, the amount of liquid draining in one withdrawal process is large. Therefore, replacement of the old and new functional liquids in the functional liquid supply apparatus 101 can be performed efficiently in a short time. For this reason, the number of repetitions can be reduced as much as possible.

  In this embodiment, functional liquid replacement is performed using one sub tank 121 as a replacement unit, but functional liquid replacement may be performed using two or more sub tanks 121 as a replacement unit.

  The new functional liquid may be a cleaning liquid that cleans the entire flow path from the main tank 181 to the functional liquid droplet ejection head 17. In this case, if the solvent of the functional liquid is used as the cleaning liquid, the number of repetitions can be extremely reduced.

  DESCRIPTION OF SYMBOLS 1 ... Droplet discharge device 7 ... Functional liquid supply unit 17 ... Functional liquid drop discharge head 71 ... Liquid reservoir 72 ... Liquid pool liquid level detection sensor 98 ... Discharge nozzle 121 ... Sub tank 164 ... Outflow side port 171 ... Sub tank main body 172 ... Lid float 176 ... Liquid column pipe 178 ... Upper limit detection sensor 179 ... Lower limit detection sensor 181 ... Main tank 183 ... Switching mechanism

Claims (7)

A functional liquid tank that receives functional liquid from a functional liquid supply source and supplies functional liquid to an ink jet type functional liquid droplet ejection head,
A tank body with a liquid reservoir recessed into the bottom facing the outflow port,
A functional liquid tank, comprising: a liquid pool level detecting unit that faces the liquid pool section and detects a liquid level of the functional liquid in the liquid pool section. A liquid column pipe attached to the tank body;
An upper limit liquid level detecting means for detecting the upper limit liquid level of the functional liquid stored in the tank body facing the liquid column pipe, and a lower limit liquid level detecting means for detecting the lower limit liquid level,
The functional liquid tank according to claim 1, wherein the liquid reservoir is disposed below a lower communication part of the liquid column pipe communicating with the tank body.   The functional liquid tank according to claim 1, further comprising a float that is accommodated in the tank body and floats and sinks with a minute gap formed on an inner wall of the tank body. A functional liquid tank according to claim 3, a functional liquid supply source that supplies the functional liquid to the functional liquid tank, and an inkjet-type functional liquid droplet ejection head that receives the supply of the functional liquid from the functional liquid tank. For the liquid droplet ejection device
A functional liquid replacement method for a liquid droplet ejection apparatus for replacing old and new functional liquids in all flow paths from the functional liquid supply source to the functional liquid droplet ejection head,
With the functional fluid filled in all the flow paths, the functional fluid supply source is shifted from the old functional fluid to that of the new functional fluid,
A step of extracting the functional liquid from the functional liquid tank until the functional liquid is sucked from the discharge nozzle of the functional liquid droplet discharge head and the liquid level detecting means detects the liquid level, and the upper limit liquid level detecting means The droplet is characterized in that the functional liquid is replaced with a new one by repeating a partial replacement step consisting of a liquid feeding step for feeding the functional liquid from the functional liquid supply source to the functional liquid tank until a liquid level is detected. A functional liquid replacement method for a discharge device. A droplet discharge device that replaces the old and new functional liquid in all flow paths from the functional liquid supply source through the functional liquid tank to the inkjet functional droplet discharge head,
Two main tanks that serve as the functional fluid supply source for the new functional fluid and the functional fluid supply source for the old functional fluid;
Channel switching means for switching the tank channels of the two main tanks;
A functional liquid flow path connecting the flow path switching means and the functional liquid droplet ejection head;
The functional liquid tank according to claim 3 interposed in the functional liquid flow path,
Liquid feeding means for feeding the functional liquid of each main tank to the functional liquid tank via the functional liquid flow path;
A suction means for coming into close contact with the nozzle surface of the functional liquid droplet ejection head so that the functional liquid is ejected from the nozzle of the functional liquid droplet ejection head;
A control means for controlling the flow path switching means, the liquid feeding means and the suction means,
The control means switches the flow path switching means to shift the main tank from the old functional liquid to the new functional liquid,
A function of extracting the functional liquid from the functional liquid tank until the suction means is driven and the liquid level detecting means detects the liquid level, and the functional liquid until the upper limit liquid level detecting means detects the liquid level. A droplet discharge apparatus characterized in that a partial replacement operation including a liquid supply operation for supplying a functional liquid from a supply source to the functional liquid tank is repeated a predetermined number of times to replace old and new functional liquids.   6. The droplet discharge device according to claim 5, wherein the old and new functional liquids are drawing inks having different components.   6. The liquid droplet ejection apparatus according to claim 5, wherein the new and old functional liquids are drawing ink and cleaning liquid.

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