JP2014094505A - Liquid droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid droplet discharge device in which air bubbles in a feed passage can be reduced.SOLUTION: An ink jet recorder 10 comprises a head module 50, a feed passage 30, a supply-side pump 118 for supplying ink L to the head module 50, a deaeration module and a vacuum pump 115 which are mounted in the feed passage 30 and reinforce gas dissolution capacity in the ink L compared with the normal time, and a microcomputer 202. Here, through a vacuum state higher than the normal time made by the vacuum pump 115, bubbles in the ink L are removed and the gas dissolution capacity in the ink L is reinforced. And, as the bubbles in the feed passage 30 are captured by and are dissolved in the ink L through flowing of the ink L the gas dissolution capacity of which is reinforced inside the feed passage 30, bubbles in the feed passage 30 can be reduced.

Description

  The present invention relates to a droplet discharge device.

  In the ink jet recording apparatus of Patent Document 1, ink in a sub tank is supplied to a three-way valve via a flow meter and a main deaeration device. The ink is supplied to the inkjet head through the tube, and the ink discharged from the inkjet head is poured into the dissolved oxygen meter through the tube. And in the inkjet recording device of patent document 1, when the dissolved gas amount in the ink measured with the dissolved oxygen meter exceeds the set value, the ink from the main deaerator is passed through the dissolved oxygen meter without passing through the inkjet head. The ink is circulated and the dissolved gas in the ink is removed by circulating the ink.

  The ink jet recording apparatus of Patent Document 2 includes a main tank in which ink is stored, an ink jet head that performs printing on a recording medium by discharging ink, an ink supply path that conveys ink from the main tank to the ink jet head, A deaeration device provided in the ink supply path that removes air in the ink, and passed through the deaeration device until no air bubbles emerge from the deaeration device when the deaeration device is not filled with ink. Ink transport means for transporting ink from an ink supply path downstream of the deaeration device to an ink supply path upstream of the deaeration device.

  An ink jet recording apparatus disclosed in Patent Document 3 is a gas permeable film in a method of removing dissolved gas in ink by reducing the space facing the ink to an atmospheric pressure or lower through a gas permeable film. To increase the efficiency of deaeration.

JP 2001-190529 A JP 2007-069543 A Japanese Patent Laid-Open No. 2003-341083

  An object of this invention is to obtain the droplet discharge apparatus which can reduce the bubble in a supply path.

  According to a first aspect of the present invention, there is provided a droplet discharge device including a droplet discharge unit that discharges a droplet, a supply path through which a liquid supplied to the droplet discharge unit flows, and the droplet through the supply path. A supply means for supplying a liquid to the discharge unit, and a dissolution unit provided in the supply path, which enhances the gas dissolution ability, which represents the ability of the liquid droplet discharge unit to dissolve bubbles in the liquid compared to the normal time of discharging the liquid droplets And a control means for controlling the liquid whose gas dissolving ability is enhanced to flow through the supply path when the liquid droplet ejection unit does not eject liquid droplets.

  In the droplet discharge device according to claim 2 of the present invention, the supply path includes a common channel, a plurality of individual channels connected to the common channel and connected to the plurality of droplet discharge units, A blocking means for blocking the flow of the liquid in the individual flow path, and the control means blocks the flow of the liquid to the individual flow path by the blocking means and allows the liquid to flow to the common flow path. However, after the gas dissolving capacity is enhanced by the dissolving capacity enhancing means, the blocking by the blocking means is released, and the liquid with enhanced gas dissolving capacity is controlled to flow through the common flow path and the individual flow paths. To do.

  In the droplet discharge device according to claim 3 of the present invention, the dissolution capacity enhancing means includes a pressure reducing means for reducing the pressure of the liquid, and the pressure of the liquid is reduced as compared with the normal time.

  In the droplet discharge device according to claim 4 of the present invention, the dissolution capacity enhancing unit operates the supply unit so that the flow rate of the liquid is lower than the normal time when the decompression unit is decompressed. .

  In the liquid droplet ejection apparatus according to claim 5 of the present invention, the dissolution capacity enhancing means includes a temperature changing means for raising the liquid temperature and then lowering it.

  According to the first aspect of the present invention, bubbles in the supply path can be reduced as compared with a configuration that does not enhance the gas dissolving ability of the liquid.

  The invention of claim 2 can enhance the gas dissolving ability of the liquid more efficiently than the case of enhancing the gas dissolving ability without blocking the flow of the liquid to the individual flow path.

  The invention of claim 3 can reduce bubbles in the supply path as compared with the configuration not having the pressure reducing means.

  According to the fourth aspect of the present invention, bubbles in the supply path can be further reduced as compared with the configuration in which the flow rate of the liquid is not changed when the decompression means is decompressing.

  According to the fifth aspect of the present invention, bubbles in the supply path can be reduced as compared with a configuration in which the temperature of the liquid is not changed.

1 is a schematic diagram illustrating a configuration of an ink jet recording apparatus according to a first embodiment. It is a piping diagram of the ink jet head concerning a 1st embodiment. It is a schematic diagram which shows the other Example of the deaeration module and vacuum pump which concern on 1st Embodiment. It is a block diagram of a control part which controls operation of an ink jet head concerning a 1st embodiment. (A) It is a graph which shows the relationship between the negative pressure application time when deaerated with the vacuum pump which concerns on 1st Embodiment, and the dissolved oxygen rate in ink. (B) It is a graph which shows the relationship between the deaeration when it deaerates with the vacuum pump which concerns on 1st Embodiment, and the dissolved oxygen rate in ink. It is explanatory drawing which shows the state in which an ink flows in the inkjet head which concerns on 1st Embodiment. 3 is a flowchart illustrating steps executed when the apparatus is started up in the ink jet recording apparatus according to the first embodiment. It is a flowchart which shows the process performed at the time of a maintenance in the inkjet recording device which concerns on 1st Embodiment. It is a graph which shows the relationship between the flow volume when flowing ink with the pump which concerns on 2nd Embodiment, and a dissolved oxygen rate. It is a flowchart which shows the process performed at the time of apparatus start-up in the inkjet recording device which concerns on 2nd Embodiment. It is a flowchart which shows the process performed at the time of a maintenance in the inkjet recording device which concerns on 2nd Embodiment. It is a graph which shows the change of the saturated dissolved oxygen amount of an ink when the temperature of an ink is changed with the temperature regulator which concerns on 3rd Embodiment. It is a flowchart which shows the process performed at the time of apparatus start-up in the inkjet recording device which concerns on 3rd Embodiment. It is a flowchart which shows the process performed at the time of a maintenance in the inkjet recording device which concerns on 3rd Embodiment.

(First embodiment)
An example of a droplet discharge device according to the first embodiment of the present invention will be described.

(overall structure)
FIG. 1 shows an inkjet recording apparatus 10 as an example of a droplet discharge apparatus that discharges ink droplets LA as an example of a droplet and records an image on a recording medium P. The inkjet recording apparatus 10 includes a storage unit 12 that stores a recording medium P, an image recording unit 14 that records an image on the recording medium P, and a transport unit 16 that transports the recording medium P from the storage unit 12 to the image recording unit 14. And a discharge unit 18 from which the recording medium P on which an image is recorded by the image recording unit 14 is discharged.

  The image recording unit 14 includes inkjet heads 20Y, 20M, 20C, and 20K. The inkjet heads 20Y, 20M, 20C, and 20K have a plurality of nozzles 24 (see FIG. 2). The nozzle surfaces 22Y, 22M, 22C, and 22K on which the nozzles 24 are provided have a recordable area that is about the same as or larger than the maximum width of the recording medium P.

  Further, the inkjet heads 20Y, 20M, 20C, and 20K are arranged in parallel in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the downstream side in the conveyance direction of the recording medium P. The ink drops LA corresponding to each color are ejected from a plurality of nozzles 24 (see FIG. 2) by a piezoelectric method, and an image is recorded on the recording medium P. In the following description, Y, M, C, and K alphabets are added to the reference numerals when it is necessary to distinguish the ink colors. In addition, when it is not necessary to distinguish the ink colors, the letters Y, M, C, and K may be omitted.

  The ink jet recording apparatus 10 is provided with a main tank 56 as a storage unit for storing ink L as an example of liquid for each color, and each ink jet from the main tank 56Y, 56M, 56C, 56K for each color. Ink L is supplied to the heads 20Y, 20M, 20C, and 20K. As the ink L supplied to the inkjet heads 20Y, 20M, 20C, and 20K, various inks such as water-based ink, oil-based ink, and solvent-based ink can be used.

  The conveying means 16 conveys the recording medium P to the take-out drum 28 for taking out the recording medium P in the storage unit 12 one by one and the ink jet heads 20Y, 20M, 20C, 20K of the image recording unit 14, and the recording surface (surface) ) To the inkjet heads 20Y, 20M, 20C, and 20K, and a delivery drum 32 that feeds the recording medium P on which an image is recorded to the discharge unit 18. The take-out drum 28, the transport drum 32, and the delivery drum 34 are configured to hold the recording medium P on the outer peripheral surface by electrostatic suction means or non-electrostatic suction means such as suction or adhesion. Yes.

  The take-out drum 28, the transport drum 32, and the delivery drum 34 are each provided with two sets of grippers 36 that hold the downstream end portion in the transport direction of the recording medium P at intervals in the circumferential direction. ing. The take-out drum 28, the transport drum 32, and the delivery drum 34 are configured to hold up to two recording media P on their outer peripheral surfaces by the gripper 36. The grippers 36 are provided in recesses 28 </ b> A, 32 </ b> A, 34 </ b> A formed on the outer peripheral surfaces of the take-out drum 28, the transport drum 32, and the delivery drum 34.

  Specifically, the rotation shaft 42 along the rotation shaft 38 of the take-out drum 28, the transport drum 32, and the delivery drum 34 is supported at predetermined positions in the recesses 28A, 32A, 34A. The shaft 42 is provided with a plurality of grippers 36 at intervals in the axial direction. Therefore, when the rotation shaft 42 is rotated in the forward direction (for example, clockwise direction shown in the figure) or the reverse direction (for example, counterclockwise direction in the figure) by an actuator (not shown), the gripper 36 is moved to the take-out drum 28, the transport drum 32, In addition, it rotates in the forward or reverse direction along the circumferential direction of the delivery drum 34, and holds or separates the downstream end in the transport direction of the recording medium P.

  That is, the gripper 36 rotates so that its front end part slightly protrudes from the outer peripheral surfaces of the take-out drum 28, the transport drum 32, and the delivery drum 34, so that the outer peripheral surface of the take-out drum 28 and the outer peripheral surface of the transport drum 32. The recording medium P is delivered from the gripper 36 of the take-out drum 28 to the gripper 36 of the transport drum 32 at a delivery position 44 where the two face each other. Further, the recording medium P is delivered from the gripper 36 of the delivery drum 32 to the gripper 36 of the delivery drum 34 at a delivery position 46 where the outer circumference of the delivery drum 32 and the outer circumference of the delivery drum 34 face each other.

  In addition, the inkjet recording apparatus 10 includes a maintenance unit (not shown) that maintains the inkjet heads 20Y, 20M, 20C, and 20K. The maintenance unit includes a cap that covers the nozzle surfaces 22Y, 22M, 22C, and 22K of the inkjet heads 20Y, 20M, 20C, and 20K, a receiving member that receives the ink droplet LA that has been preliminarily ejected (empty ejection), and the nozzle surfaces 22Y, 22M, and 22C. , A cleaning member for cleaning 22K, a suction device for sucking ink in the nozzles, and the like. Then, various maintenance operations are performed by moving the maintenance unit to a position facing the inkjet heads 20Y, 20M, 20C, and 20K.

(Image recording operation)
Next, an image recording operation of the inkjet recording apparatus 10 will be described.

  The recording medium P, which is taken out from the storage unit 12 one by one by the gripper 36 of the take-out drum 28 and held on the outer peripheral surface of the take-out drum 28, is conveyed while being attracted to the outer peripheral surface of the take-out drum 28. Then, at the delivery position 44, the paper is delivered from the gripper 36 of the take-out drum 28 to the gripper 36 of the transport drum 32. The recording medium P held by the gripper 36 of the transport drum 32 is transported to the image recording positions of the inkjet heads 20Y, 20M, 20C, and 20K while being attracted to the outer peripheral surface of the transport drum 32, and the inkjet heads 20Y, 20M, An image is recorded on the recording surface by ink droplets LA ejected from 20C and 20K.

  Subsequently, the recording medium P on which an image is recorded on the recording surface is transferred from the gripper 36 of the transport drum 32 to the gripper 36 of the delivery drum 34 at the transfer position 46. The recording medium P held by the gripper 36 of the delivery drum 34 is conveyed while being attracted to the outer peripheral surface of the delivery drum 34, and is discharged to the discharge unit 18. A series of image recording operations are performed as described above.

(Configuration of each part)
Next, the configuration of each part of the inkjet recording apparatus 10 will be described.

  FIG. 2 shows a piping diagram from the main tank 56 that stores the ink L to the inkjet head 20. The ink jet recording apparatus 10 includes a main tank 56 that stores ink L, a plurality of head modules 50 as an example of a droplet discharge unit that discharges ink droplets LA (see FIG. 1), and ink supplied to the head module 50. And a supply path 30 through which L flows (ink L flows from the main tank 56 to each head module 50). Each head module 50 is formed with a plurality of nozzles 24 from which ink droplets LA (see FIG. 1) are ejected, as described above. The supply path 30 includes a supply side main pipe 98, a supply pipe 74, and a supply side branch path 62, which will be described later.

  Each head module 50 is provided with an input port 52A through which ink L flows and an output port 52B through which ink L is discharged. The input port 52A is attached with the tip of a supply side branch path 62 as an example of an individual flow path branched from a supply side manifold 58 as an example of a common path, and the output port 52B is branched from a recovery side manifold 64. The tip of the collected recovery branch 66 is attached.

  That is, the supply side manifold 58 and the recovery side manifold 64 are provided with as many branch pipes (supply side branch paths 62 and recovery side branch paths 66) as the head modules 50 are installed. The ink jet recording apparatus 10 supplies the ink L supplied to the supply side manifold 58 to each head module 50 at a predetermined pressure (P1) and a predetermined flow rate. Ink L supplied to each is recovered from each head module 50 to the recovery-side manifold 64 at a predetermined pressure (P2) and a predetermined flow rate.

  Here, in the head module 50, pressure P1 and pressure are applied to the nozzle surface 22 by generating a differential pressure ΔP (= P1-P2) between the supply-side pressure P1 and the recovery-side pressure P2. A back pressure P3 that is an average pressure of the sum total with P2 is applied. Ink is held by the plurality of nozzles 24 of the head module 50 by the back pressure P3. Then, by driving an energy generating element (not shown) for ink discharge, the ink L is discharged according to the image information. Illustration of the pressures P1, P2 and the back pressure P3 is omitted.

  The supply side branch path 62 is provided with a supply side valve 68 and a damper 70 as an example of a blocking means. Further, the recovery side branch path 66 is provided with a recovery side valve 72 and a damper 70. The supply side valve 68 and the recovery side valve 72 are opened and closed when the head module 50 needs to be individually operated, and the damper 70 is the ink L supplied from the supply side manifold 58 or the recovery side. It serves to alleviate pressure fluctuations during the flow of the ink L collected in the manifold 64.

  One end of a supply pipe 74 constituting a part of the supply path 30 is attached to one end in the longitudinal direction (the right end portion in FIG. 2) of the supply side manifold 58, and one end in the longitudinal direction is attached to the recovery side manifold 64. One end of a recovery pipe 76 that constitutes a part of the piping system for circulating the ink L is attached to the right end of FIG. A first channel 78 and a second channel 82 are provided between the other end of the supply side manifold 58 and the other end of the recovery side manifold 64.

  A first valve 84 is provided in the first flow path 78. The second flow path 82 is provided with a second valve 86. The first flow path 78 and the second flow path 82 are used for pressure adjustment between the supply side manifold 58 and the recovery side manifold 64, ink flow rate adjustment, and the like. For example, in the normal circulation of the ink L (the flow of the ink L from the supply side manifold 58 to the recovery side manifold 64), the first valve 84 is closed and the second valve 86 is opened, and the ink L flows in the second flow. Only the road 82 can be distributed.

  Further, a supply-side pressure sensor 88 and a recovery-side pressure sensor 92 are attached to the other end of the supply-side manifold 58 and the other end of the recovery-side manifold 64, respectively. Thus, the pressure of the ink L flowing in the supply side manifold 58 and the recovery side manifold 64 is monitored.

  The other end of the supply pipe 74 connected to the supply side manifold 58 is connected to the supply side sub tank 94. The supply-side subtank 94 has a two-chamber structure in which the inside is partitioned by an elastic film member 96. The lower side is an ink subtank chamber 94A and the upper side is an air chamber 94B. One end of a supply-side main pipe 98 for drawing ink L from a buffer tank 112 connected to the main tank 56 is connected to the ink sub tank chamber 94A. The other end of the supply-side main pipe 98 is connected to the buffer tank 112. An open pipe 95 is connected to the air chamber 94B, and a supply-side air connect valve 97, a supply-side air tank 99, and a supply-side air valve 101 are provided in the open pipe 95.

  Supply means 98 supplies pressure to the head module 50 via the deaeration module 114, the one-way valve 116, and the supply path 30 in order from the buffer tank 112 to the supply side sub tank 94. As an example, a supply-side pump 118, a supply-side filter 122, and an ink temperature adjuster 124 are provided. As an example, the ink temperature adjuster 124 includes a heater and a fan (not shown), and the ink L is heated by the heater and cooled by the fan.

  For example, the deaeration module 114 includes a two-layered cylinder (not shown), and this cylinder is formed of a film that allows only gas molecules to pass therethrough. In addition, a vacuum pump 115 having a negative pressure changing function is connected to the deaeration module 114, and when the vacuum pump 115 is operated, pressure reduction is performed in the deaeration module 114, and bubbles in the ink L To degas. As a result, air bubbles are removed from the ink L and the temperature of the ink L is managed while the ink L stored in the buffer tank 112 is being supplied to the supply side sub tank 94 by the driving force of the supply side pump 118.

  Here, the deaeration module 114, the vacuum pump 115, and the dissolution capacity control unit 214 are an example of a dissolution capacity enhancement unit that enhances the gas dissolution capacity described later, and the vacuum pump 115 decompresses the ink L to reduce the ink L It is an example of the decompression means which removes a bubble from. That is, the deaeration module 114 and the vacuum pump 115 are provided in the supply path 30 and represent the ability to dissolve bubbles in the ink L compared to the normal time when the head module 50 ejects the ink droplet LA (see FIG. 1). Enhance gas dissolving ability. Details of the gas dissolving ability will be described later.

  As shown in FIG. 3, as another example of the configuration around the deaeration module 114, a branch pipe 123 is connected in the middle of a pipe 121 connecting the deaeration module 114 and the vacuum pump 115. 123 may have a configuration in which an opening / closing valve 117 and a filter 119 are provided. The side of the filter 119 opposite to the opening / closing valve 117 side is open to the atmosphere, and the filter 119 acts as a gas resistance, so that the degree of deaeration vacuum is higher than that during normal printing.

  One end of the branch pipe 126 is connected to the inlet side of the supply side pump 118 separately from the supply side main pipe 98, and the other end of the branch pipe 126 is connected to the buffer tank 112 through the one-way valve 128. Yes. Further, the temperature of the ink temperature adjuster 124 is managed by the dissolution capacity control unit 214. Further, each pipe is connected by a coupling portion 113.

  As an example, the supply-side pump 118 is configured by a tube pump using a stepping motor (not shown) (supplying ink in the tube while squeezing a tube having elasticity by a stepping motor being rotated). In particular, it is not limited to such a pump. In addition, one end of a drain pipe 132 is connected to the ink sub tank chamber 94 </ b> A, and the other end of the drain pipe 132 is connected to the buffer tank 112. The drain pipe 132 is provided with a supply-side drain valve 134.

  Since the supply side subtank 94 has a structure in which bubbles in the flow path are trapped by circulating the ink L, the supply side drain valve 134 is opened, and the supply side subtank 94 is driven by the driving force of the supply side pump 118. The bubbles are discharged from the buffer tank 112 opened to the atmosphere by being sent to the buffer tank 112.

  Next, the other end of the recovery pipe 76 connected to the recovery side manifold 64 is connected to the recovery side sub tank 142. The collection-side sub tank 142 has a two-chamber structure in which the inside is partitioned by an elastic film member 144. The lower side is an ink sub-tank chamber 146A and the upper side is an air chamber 146B. One end of a collection-side main pipe 148 for drawing ink into the buffer tank 112 is connected to the ink sub tank chamber 146A. An open pipe 152 is connected to the air chamber 146B, and a recovery side air connect valve 154, a recovery side air tank 156, and a recovery side air valve 158 are provided in the open pipe 152.

  The collection side main pipe 148 is provided with a collection side pump 149. Further, a pressure purge pipe 162 is provided between the inlet side of the recovery side pump 149 and the outlet side of the deaeration module 114 in the supply side main pipe 98. A one-way valve 168 and a recovery filter 170 are provided in order from the degassing module 114 to the recovery side pump 149 in the pressure purge pipe 162. That is, when reducing the bubbles by pressurizing the inside of the head module 50 and discharging ink at a stroke, in addition to driving the supply side pump 118, the drive direction of the recovery side pump 149 is reversed with respect to the normal time, The degassed ink L is supplied from the buffer tank 112 to the recovery side manifold 64.

  In the buffer tank 112, the main tank 56 and the ink L can be circulated by a replenishment pipe 172 provided with a replenishment pump 176. The buffer tank 112 stores an amount of ink necessary to circulate the ink L, and the ink L is replenished from the main tank 56 as the ink L is consumed. A filter 174 is provided at one end of the refilling pipe 172 (in the main tank 56). An overflow pipe 178 is provided between the buffer tank 112 and the main tank 56 so that the ink L is returned to the main tank 56 when the ink L is replenished excessively.

  One end of the branch pipe 164 is connected to the recovery side main pipe 148 upstream of the recovery side pump 149, and the other end of the branch pipe 164 is connected to the overflow pipe 178. The branch pipe 164 is provided with a safety valve 165. Furthermore, one end of the branch pipe 166 is connected to the collection side main pipe 148 downstream of the collection side pump 149, and the other end of the branch pipe 166 is connected to the downstream side of the replenishment pump 176 in the replenishment pipe 172. Has been. The branch pipe 166 is provided with a one-way valve 167.

  Here, the ink L in the collection side sub tank 142 is collected into the buffer tank 112 by the driving force of the collection side pump 149. In addition, one end of a drain pipe 147 is connected to the ink sub-tank chamber 146A, and the other end of the drain pipe 147 is connected to the drain pipe 132 through the recovery-side drain valve 151.

  Since the collection-side sub tank 142 has a structure in which bubbles in the flow path are trapped by circulating the ink L, the collection-side drain valve 151 is opened to drive the collection-side pump 149 with a driving force due to the reverse rotation. Bubbles in the collection-side sub tank 142 are sent to the buffer tank 112, and the bubbles are discharged from the buffer tank 112 that is open to the atmosphere.

  One end of a branch pipe 182 is connected between the supply side filter 122 and the ink temperature adjuster 124 in the supply side main pipe 98, and the other end of the branch pipe 182 is connected to the branch pipe 164 in the overflow pipe 178. It is connected downstream from the connection position. The branch pipe 182 is provided with a safety valve 184.

  In the present embodiment, the pressure P1 of the supply side manifold 58 and the pressure P2 of the recovery side manifold 64 have a relationship of P1> P2, but each is a negative pressure supply. That is, the supply pressure of the supply side pump 118 is negative, but the recovery pressure of the recovery side pump 149 is further negative, so that the ink flows from the supply side manifold 58 to the recovery side manifold 64 and the head module 50. The back pressure P3 of the nozzle 24 is maintained at a negative pressure ((P1 + P2) / 2). Strictly speaking, as the elements of the back pressure P3, the height position of the supply side manifold 58 and the recovery side manifold 64, the ink flow rate, the flow path resistance, and the like are involved, so the pressure P1 on the input side and the pressure P2 on the output side. Should be taken into account when setting

(Configuration of control unit)
Next, the control unit 200 of the inkjet recording apparatus 10 will be described.

  As shown in FIG. 4, the inkjet recording apparatus 10 includes a control unit 200 that controls the operation of each unit based on an input signal and discharges ink L from the head module 50 (see FIG. 2). .

  The control unit 200 controls the microcomputer 202 and the gas module dissolving ability (described later) of the head module control unit 204, the pressure control unit 206, the drain control unit 208, the pump control unit 212, and the ink L connected to the microcomputer 202. And a dissolution capacity control unit 214. The microcomputer 202 includes a CPU 216, a RAM 218, a ROM 222, an I / O unit 224, and a bus 226 such as a data bus and a control bus for connecting them. The microcomputer 202 is an example of a control unit that controls the ink L with enhanced gas dissolving ability, which will be described later, to flow through the supply path 30 when the head module 50 (see FIG. 2) does not eject the ink droplet LA. is there.

  A hard disk drive (HDD) 228 is connected to the I / O unit 224. Further, a supply side pressure sensor 88 and a recovery side pressure sensor 92 are connected to the I / O unit 224. Furthermore, image data when an image is formed by ejecting ink L from the nozzles 24 (see FIG. 2) of the head module 50 is input to the I / O unit 224 from the outside. Note that the image data may be data in which the ink ejection position and ejection amount are determined, or may be compressed data such as JPEG. Further, the CPU 216 reads and executes the ink circulation system program stored in the ROM 222.

  As an example, the ink circulation system program causes the ink L in the buffer tank 112 shown in FIG. 2 to flow from the supply side manifold 58 to the recovery side manifold 64 and circulate, and the ink droplet LA ( 1) and a purge control program for discharging (purging) bubbles generated in the head module 50, and a gas dissolution capacity control for increasing the gas dissolution capacity of the ink L described later. There is a program. The ink circulation system program is not limited to the ROM 222, but is stored in the HDD 228 or an external storage medium (not shown), and a network such as a reader or LAN (not shown) that reads information by loading the external storage medium. You may make it acquire from.

  In the following description, the time when the control for ejecting the ink droplets LA (see FIG. 1) from the nozzles 24 for recording (forming) the image on the recording medium P is performed based on the control program is the normal recording and the normal recording. When the apparatus is started up, the time when the apparatus is started up, and when the image is recorded (formed) on the recording medium P and then prepared so that the normal recording can be performed, is called the maintenance time.

  As shown in FIG. 4, the CPU 216, based on the read circulation control program, the head module control unit 204, the pressure control unit 206, the drain control unit 208, the pump control unit 212, and the like connected to the I / O unit 224. The operation of the dissolution capacity control unit 214 is controlled.

  The head module control unit 204 discharges the ink droplet LA from the nozzle 24 (see FIG. 2) by the vibration of the pressure chamber by the energization control of the piezoelectric element or the like built in the head module 50. Device), supply side valve 68, recovery side valve 72, first valve 84, and second valve 86 are connected. Further, a supply side air connect valve 97, a supply side air valve 101, a recovery side air connect valve 154, and a recovery side air valve 158 are connected to the pressure control unit 206.

  A supply-side drain valve 134 and a recovery-side drain valve 151 are connected to the drain control unit 208. In addition, a recovery side pump 149 and a replenishment pump 176 are connected to the pump control unit 212. Further, a vacuum pump 115, a supply-side pump 118, and an ink temperature controller 124 are connected to the dissolution capacity control unit 214. When the apparatus is started up, the supply side valve 68 (closed), the recovery side valve 72 (closed), the first valve 84 (closed), the second valve 86 (closed), the supply side air connect valve 97 (open), The supply side air valve 101 (closed), the supply side drain valve 134 (closed), the recovery side drain valve 151 (closed), the recovery side air connect valve 154 (open), and the recovery side air valve 158 (closed).

(Gas dissolving ability of ink L)
Next, the gas dissolving ability of the ink L will be described.

  5A, the vacuum pump 115 (see FIG. 2) is operated, and the negative pressure in the deaeration module 114 (see FIG. 2) is set to −80 [kPa], −90 [kPa], and −97 [kPa]. The graph shows the change in the dissolved oxygen ratio in the ink L with respect to the negative pressure application time. FIG. 5B is a graph showing the relationship between the negative pressure (degassing pressure) when deaerated with the vacuum pump 115 and the dissolved oxygen ratio in the ink L.

  The dissolved oxygen ratio (hereinafter referred to as R) is the amount of saturation in the ink L, with the saturation amount when the oxygen dissolved in the ink L is saturated at a constant temperature being 100%. This is a ratio indicating whether oxygen is dissolved.

  The gas dissolving ability represents the ability to dissolve bubbles in the ink L. As an example, when the gas is oxygen, it can be expressed as gas dissolving ability = (100 [%] − R [%]). That is, the gas dissolving capacity indicates how much gas can be further dissolved in the ink L, and the larger the value, the easier the gas is taken into the ink L.

  As shown in FIGS. 5A and 5B, it can be seen that the dissolved oxygen ratio R decreases as the degree of vacuum of the degassing module 114 increases. Further, as shown in FIG. 5A, in the supply path 30 (see FIG. 2) that is a circulation path, the time required for the dissolved oxygen ratio R to stabilize at the minimum value is, for example, 10 minutes or more. (When the capacity of the supply path 30 is 1 liter).

  The time until the dissolved oxygen rate R stabilizes at the lowest value greatly contributes to the dissolved oxygen rate R at the start of degassing (generally atmospheric pressure). As an example, when the dissolved oxygen rate R at the start of degassing is 20 [%] and degassed at a negative pressure of −97 [kPa], it takes about 5 minutes to stabilize at the lowest value, and the dissolved oxygen rate R is Decrease to about 3%.

(Function)
Next, the operation of the first embodiment will be described.

(When starting up the device)
With reference to the flowchart shown in FIG. 7, FIG. 2, and FIG. 4, the procedure for increasing the gas dissolving ability of the ink L when the ink jet recording apparatus 10 is started up, and the procedure for supplying the ink L with the increased gas dissolving ability. explain.

  In step S <b> 10, a user (not shown) turns on the ink jet recording apparatus 10. Then, the process proceeds to step S12.

  Subsequently, in step S12, the melting capacity control unit 214 turns on the power of the vacuum pump 115 and controls the operation of the vacuum pump 115 to set the negative pressure in the deaeration module 114 to −97 [kPa]. Then, the process proceeds to step S14.

  Subsequently, in step S14, the control unit 200 performs a self-check (operation check) for each unit of the inkjet recording apparatus 10, and the process proceeds to step S16.

  Subsequently, in step S <b> 16, the drain control unit 208 opens the supply-side drain valve 134, and the pump control unit 212 drives the supply-side pump 118. Then, the bubbles in the supply side sub tank 94 are sent to the buffer tank 112 by the driving force of the supply side pump 118, whereby the bubbles are discharged from the buffer tank 112 that is open to the atmosphere. Thereby, bubbles are removed from the supply side sub tank 94 (removal of gas). As an example, the time during which the supply side sub-tank 94 is degassed in step S16 is 30 seconds. Then, the process proceeds to step S18.

  Subsequently, in step S18, the drain control unit 208 opens the recovery-side drain valve 151, and the pump control unit 212 drives the recovery-side pump 149 to rotate in the reverse direction. The bubbles in the collection side sub tank 142 are sent to the buffer tank 112 by the driving force of the collection side pump 149, whereby the bubbles are discharged from the buffer tank 112 that is open to the atmosphere. Thereby, bubble removal (removal of gas) of the collection | recovery side sub tank 142 is performed. As an example, the time during which bubbles are removed from the collection-side sub tank 142 in step S18 is 30 seconds. Then, the process proceeds to step S20.

  Subsequently, in step S20, air removal from the manifold bypass channel is performed. The bubble removal of the manifold bypass flow path means discharging the bubbles in the order of the supply side sub tank 94, the supply side manifold 58, the second flow path 82, the recovery side manifold 64, the recovery side sub tank 142, the drain pipe 147, and the buffer tank 112. That is. As an example, the time during which bubbles are removed from the manifold bypass channel in step S20 is 10 seconds. Then, the process proceeds to step S22.

  Subsequently, in step S22, air bubbles are removed from the manifold. As shown in FIG. 6, the air bubbles are discharged from the manifold in the order of the supply side sub tank 94, the supply side manifold 58, the first flow path 78, the recovery side manifold 64, the branch pipe 166, and the buffer tank 112. It is. In FIG. 6, a path (flow path) in which the ink L flows is indicated by a solid line, and a path (flow path) in which the ink L does not flow is indicated by a broken line. As an example, the time during which bubbles are removed from the manifold bypass channel in step S22 is 15 minutes.

  Here, when the ink L is circulated, the deaeration module 114 performs deaeration at −97 [kPa], which has a negative pressure higher than the normal negative pressure −90 [kPa]. Gas (as an example, oxygen) is degassed to enhance (improve) the gas dissolution capacity of the ink L. That is, the ink L having a higher gas dissolving ability than normal is generated. Then, the process proceeds to step S24.

  Subsequently, in step S24, the head module control unit 204 opens the supply side valve 68 and the recovery side valve 72 connected to each head module 50, and supplies each head module 50 with ink L having a higher gas dissolving capacity than normal. To do. Since the ink L also circulates in the head module 50, the ink jet recording apparatus 10 absorbs bubbles generated while the operation is stopped and extinguishes them. Thereby, bubbles in the supply path 30 and the head module 50 are reduced. As an example, the time for removing the air bubbles from the head module 50 in step S24 is 15 minutes. Then, the process proceeds to step S26.

  Subsequently, in step S26, the melting capacity control unit 214 controls the operation of the vacuum pump 115 so that the negative pressure in the deaeration module 114 is -90 [kPa]. That is, it is set as the normal negative pressure. Then, the process proceeds to step S28.

  Subsequently, in step S28, the completion of the preparation of the ink jet recording apparatus 10 is displayed on a display panel (not shown) provided in the ink jet recording apparatus 10. Thereby, the apparatus start-up of the inkjet recording apparatus 10 is completed.

(During maintenance)
With reference to the flowchart shown in FIG. 8, FIG. 2, and FIG. 4, a procedure for increasing the gas dissolving ability of the ink L during maintenance of the inkjet recording apparatus 10 and a procedure for supplying the ink L with the increased gas dissolving ability will be described. To do.

  In step S30, the melting capacity control unit 214 controls the operation of the vacuum pump 115, and switches the negative pressure in the deaeration module 114 from normal −90 [kPa] to −97 [kPa]. As an example, step S30 is performed for 5 minutes. Here, in the degassing module 114, degassing is performed at −97 [kPa], which has a negative pressure higher than the normal negative pressure −90 [kPa], and therefore, gas (for example, oxygen) in the ink L is generated. While deaerated, the gas dissolving ability of the ink L is improved. That is, the ink L having a higher gas dissolving ability than normal is generated. Then, the process proceeds to step S32.

  Subsequently, in step S <b> 32, the supply side valve 68 and the recovery side valve 72 connected to each head module 50 are opened, and the ink L having a higher gas dissolving capacity than normal is supplied to each head module 50. Since the ink L also circulates in the head module 50, the ink jet recording apparatus 10 absorbs bubbles generated while the operation is stopped and extinguishes them. Thereby, bubbles in the supply path 30 and the head module 50 are reduced. As an example, the time during which air bubbles are removed from the head module 50 in step S32 is 15 minutes. Then, control goes to a step S34.

  Subsequently, in step S34, the melting capacity control unit 214 controls the operation of the vacuum pump 115 so that the negative pressure in the deaeration module 114 is -90 [kPa]. That is, it is set as the normal negative pressure. Then, the process proceeds to step S36.

  Subsequently, in step S36, the completion of the preparation of the ink jet recording apparatus 10 is displayed on a display panel (not shown) provided in the ink jet recording apparatus 10. Thereby, the bubble removal of the ink L at the time of maintenance is completed.

  The reason why the bubbles are not removed during printing (during recording) with the ink L with improved gas dissolving ability is that if the deaeration at a high vacuum is continued for a long time, the water in the ink L evaporates and the pigment is removed. This is because component precipitation, thickening of the ink L, and condensation in the vacuum path are concerned. However, it has been confirmed that high vacuum degassing for 10 minutes to 20 minutes does not damage the ink L or the vacuum system.

(Second Embodiment)
Next, an example of a droplet discharge device according to the second embodiment of the present invention will be described.

  The droplet discharge device of the second embodiment is mechanically similar in configuration to the ink jet recording device 10 of the first embodiment described above, and the flow rate of the ink L at the time of bubble removal is different (normal time). Less than the flow rate). For this reason, the second embodiment is also described as the ink jet recording apparatus 10, and the same reference numerals as those in the first embodiment are given to basically the same members as those of the ink jet recording apparatus 10 of the first embodiment described above. The description is omitted.

(Gas dissolving ability of ink L)
Next, the gas dissolving ability of the ink L in the second embodiment will be described.

  FIG. 9 shows the flow rate (unit ml (milliliter) / min (min)) and dissolved oxygen when saturated dissolved oxygen water (dissolved oxygen rate 100%) is passed once through the degassing module 114 (see FIG. 2). The relationship with the rate R (unit%) is shown. The negative pressure is set to −88 [kPa].

  As shown in the graph of FIG. 9, it can be seen that the dissolved oxygen ratio R decreases as the flow rate decreases. As an example, if the normal circulating flow rate 600 [ml / min] is 200 [ml / min], the dissolved oxygen ratio by one passage through the degassing module 114 is 34% to 19%. In other words, the gas dissolving ability is improved by reducing the flow rate. For this reason, in the inkjet recording apparatus 10 of the second embodiment shown in FIG. 2, the flow rate (that is, the flow velocity) of the ink L by the supply-side pump 118 is lower than normal, and the gas of the ink L that passes through the deaeration module 114. Strengthen dissolution capacity.

(Function)
Next, the operation of the second embodiment will be described.

(When starting up the device)
With reference to the flowchart shown in FIG. 10, FIG. 2, and FIG. 4, the procedure for increasing the gas dissolving ability of the ink L at the start-up of the ink jet recording apparatus 10 of the second embodiment, and the ink L having the increased gas dissolving ability. The procedure for supplying the will be described. In addition, about the procedure similar to 1st Embodiment, the same step number as 1st Embodiment is provided and the description is abbreviate | omitted. However, the same steps may be described.

  After performing Step S10, the process proceeds to Step S13. In step S13, the melting capacity control unit 214 turns on the power of the vacuum pump 115 and controls the operation of the vacuum pump 115, so that the negative pressure in the deaeration module 114 is −90 [kPa] (negative in normal operation). Pressure). And it transfers to step S14, and after performing step S14, S16, S18, S20, S22, it transfers to step S23.

  Subsequently, in step S23, the dissolution capacity control unit 214 controls the operation of the supply-side pump 118, and the flow rate of the ink L by the supply-side pump 118 is changed from 600 [ml / min] at normal time to 100 [ml / min]. Reduce. As a result, even if the degassing module 114 is at a normal negative pressure, the deaeration amount increases as the flow rate of the ink L decreases, so that the gas (for example, oxygen) in the ink L is degassed. The gas dissolving ability of the ink L is improved. That is, the ink L having a higher gas dissolving ability than normal is generated. In addition, it waits for 5 minutes as an example until gas dissolution capability is stabilized. Then, the process proceeds to step S24.

  Subsequently, in step S24, the head module control unit 204 opens the supply side valve 68 and the recovery side valve 72 connected to each head module 50, and supplies each head module 50 with ink L having a higher gas dissolving capacity than normal. To do. Since the ink L also circulates in the head module 50, the ink jet recording apparatus 10 absorbs bubbles generated while the operation is stopped and extinguishes them. Thereby, bubbles in the supply path 30 and the head module 50 are reduced. As an example, the time for removing the air bubbles from the head module 50 in step S24 is 15 minutes. Then, the process proceeds to step S27.

  Subsequently, in step S27, the dissolution capacity control unit 214 controls the operation of the supply-side pump 118, and the flow rate of the ink L by the supply-side pump 118 is changed from 100 [ml / min] to 600 [ml / min] at normal time. increase. Then, the process proceeds to step S28, and the apparatus start-up of the inkjet recording apparatus 10 is completed.

(During maintenance)
With reference to the flowchart shown in FIG. 11, FIG. 2, and FIG. 4, the procedure for increasing the gas dissolution capacity of the ink L during maintenance of the inkjet recording apparatus 10 of the second embodiment, and the ink L with the increased gas dissolution capacity. The supply procedure will be described. In addition, about the procedure similar to 1st Embodiment, the same step number as 1st Embodiment is provided and the description is abbreviate | omitted. However, the same steps may be described.

  In step S31, the dissolution capacity control unit 214 controls the operation of the supply-side pump 118, and reduces the flow rate of the ink L in the deaeration module 114 from 600 [ml / min] at normal time to 100 [ml / min]. As a result, even if the degassing module 114 is at a normal negative pressure, the deaeration amount increases as the flow rate of the ink L decreases, so that the gas (for example, oxygen) in the ink L is degassed. The gas dissolving ability of the ink L is improved. That is, the ink L having a higher gas dissolving ability than normal is generated. In addition, it waits for 5 minutes as an example until gas dissolution capability is stabilized. Then, the process proceeds to step S32.

  Subsequently, in step S32, the head module control unit 204 opens the supply side valve 68 and the recovery side valve 72 connected to each head module 50, and supplies each head module 50 with ink L having a higher gas dissolving capacity than normal. To do. Since the ink L also circulates in the head module 50, the ink jet recording apparatus 10 absorbs bubbles generated while the operation is stopped and extinguishes them. Thereby, bubbles in the supply path 30 and the head module 50 are reduced. As an example, the time during which air bubbles are removed from the head module 50 in step S32 is 15 minutes. Then, the process proceeds to step S35.

  Subsequently, in step S35, the dissolution capacity control unit 214 controls the operation of the supply-side pump 118, and the flow rate of the ink L in the deaeration module 114 is changed from 100 [ml / min] to 600 [ml / min] (normal time) ) To increase. Then, the process proceeds to step S36, and the bubble removal of the ink L at the time of maintenance is completed.

  The reason why the bubbles are not removed during printing (recording) with the ink L with improved gas dissolution capability is that the temperature of the ink L in each head module 50 is the temperature required for printing in circulation at a low flow rate. This is because it cannot be controlled.

(Third embodiment)
Next, an example of a droplet discharge device according to the third embodiment of the present invention will be described.

  The droplet discharge device of the third embodiment is mechanically similar in configuration to the ink jet recording device 10 of the first embodiment described above, and the dissolving capacity control unit 214 and the ink temperature adjuster 124 are provided with the ink L It is an example of the temperature change means to make it fall after raising the temperature of this. And the temperature of the ink L at the time of bubble reduction differs from 1st Embodiment. For this reason, the third embodiment is also described as the ink jet recording apparatus 10, and basically the same members as those of the ink jet recording apparatus 10 of the first embodiment described above are given the same reference numerals as in the first embodiment. The description is omitted.

(Gas dissolving ability of ink L)
Next, the gas dissolving ability of the ink L in the third embodiment will be described.

  FIG. 12 shows a change in the saturated dissolved oxygen amount of the ink L when the temperature of the ink L is changed by the ink temperature adjuster 124. The negative pressure is −90 [kPa].

  As shown in the graph of FIG. 12, the higher the temperature of the ink L, the smaller the amount of oxygen that can be dissolved in the ink L. When the temperature of the ink L is increased, oxygen exceeding the amount of saturated dissolved oxygen at that temperature is vaporized. Here, when oxygen is saturated in the ink L, when the temperature of the ink L is raised and then lowered, the difference from the saturated dissolved oxygen amount at the lowered temperature is the amount of oxygen that the ink L can take up. become. In other words, the gas dissolving ability is improved by changing the temperature of the ink L from the normal temperature to the high temperature and low temperature. For this reason, in the inkjet recording apparatus 10 of the third embodiment shown in FIG. 2, the temperature of the ink L by the ink temperature adjuster 124 is changed to enhance the gas dissolving ability of the ink L.

(Function)
Next, the operation of the third embodiment will be described.

(When starting up the device)
With reference to the flowchart shown in FIG. 13, FIG. 2, and FIG. 4, the procedure for increasing the gas dissolution capacity of the ink L at the start-up of the inkjet recording apparatus 10 of the third embodiment, and the ink L with the increased gas dissolution capacity The procedure for supplying the will be described. In addition, about the procedure similar to 1st, 2nd embodiment, the same step number as 1st, 2nd embodiment is provided, and the description is abbreviate | omitted. However, the same steps may be described.

  After performing Step S10, the process proceeds to Step S13. In step S13, the melting capacity control unit 214 turns on the power of the vacuum pump 115 and controls the operation of the vacuum pump 115, so that the negative pressure in the deaeration module 114 is −90 [kPa] (negative in normal operation). Pressure). Then, the process proceeds to step S40.

  Subsequently, in step S40, the dissolution capacity control unit 214 operates the ink temperature adjuster 124 to increase the temperature of the ink L to 50 [° C.]. As an example, the temperature of the ink L is held at 50 [° C.] for 20 minutes. Thereby, the gas (for example, oxygen) in the ink L is degassed. Then, it transfers to step S14, performs step S14, S16, S18, S20, S22, and transfers to step S42.

  Subsequently, in step S42, the dissolution capacity control unit 214 operates the ink temperature adjuster 124 to lower (cool) the temperature of the ink L to 20 [° C.]. As a result, the gas dissolving ability of the ink L is improved by the difference between the saturated dissolved oxygen amount at 50 [° C.] and the saturated dissolved oxygen amount at 20 [° C.]. That is, the ink L having a higher gas dissolving ability than normal time (for example, 30 [° C.]) is generated. Then, the process proceeds to step S24.

  Subsequently, in step S24, the head module control unit 204 opens the supply side valve 68 and the recovery side valve 72 connected to each head module 50, and supplies each head module 50 with ink L having a higher gas dissolving capacity than normal. To do. Since the ink L also circulates in the head module 50, the ink jet recording apparatus 10 absorbs bubbles generated while the operation is stopped and extinguishes them. Thereby, bubbles in the supply path 30 and the head module 50 are reduced. As an example, the time for removing the air bubbles from the head module 50 in step S24 is 15 minutes. Then, the process proceeds to step S44.

  Subsequently, in step S44, the dissolving capacity control unit 214 operates the ink temperature adjuster 124 to increase the temperature of the ink L from 20 [° C.] to 30 [° C.]. Then, the process proceeds to step S28, and the apparatus start-up of the inkjet recording apparatus 10 is completed.

(During maintenance)
Referring to the flowchart shown in FIG. 14, FIG. 2, and FIG. 4, the procedure for increasing the gas dissolution capacity of the ink L during the maintenance of the inkjet recording apparatus 10 of the third embodiment, and the ink L with the increased gas dissolution capacity. The supply procedure will be described. In addition, about the procedure similar to 1st, 2nd embodiment, the same step number as 1st, 2nd embodiment is provided, and the description is abbreviate | omitted. However, the same steps may be described.

  In step S40, the dissolving capacity control unit 214 operates the ink temperature adjuster 124 to increase the temperature of the ink L to 50 [° C.]. Thereby, the gas (for example, oxygen) in the ink L is degassed. Then, the process proceeds to step S22.

  Subsequently, in step S22, air bubbles are removed from the manifold, and the process proceeds to step S42.

  Subsequently, in step S42, the dissolution capacity control unit 214 operates the ink temperature adjuster 124 to lower (cool) the temperature of the ink L to 20 [° C.]. As a result, the ink L having a higher gas dissolving ability than that at the normal time is generated. Then, the process proceeds to step S24.

  Subsequently, in step S24, each head module 50 is supplied with ink L having a higher gas dissolving ability than that in the normal state. Since the ink L also circulates in the head module 50, the ink jet recording apparatus 10 absorbs bubbles generated while the operation is stopped and extinguishes them. Thereby, bubbles in the supply path 30 and the head module 50 are reduced. Then, the process proceeds to step S44.

  Subsequently, in step S44, the dissolving capacity control unit 214 operates the ink temperature adjuster 124 to increase the temperature of the ink L from 20 [° C.] to 30 [° C.]. Then, the process proceeds to step S28, and the operation preparation of the ink jet recording apparatus 10 is completed.

  In addition, this invention is not limited to said embodiment.

  The vacuum pump 115 may have a variable regulator.

  Further, as a method for enhancing the gas dissolving ability of the ink L, a method of increasing the negative pressure by the vacuum pump 115, a method of decreasing the flow rate of the ink L by the supply side pump 118, and a method of increasing the temperature of the ink L by the ink temperature regulator 124. Any two of these may be combined, or all may be performed together.

  Further, the maintenance of the ink jet recording apparatus 10 may be performed by the user when the print quality deteriorates or periodically (at a time point based on the number of printed sheets, the amount of ink L used, the elapsed time since power-on, etc.). You may set so that it may carry out.

  In addition, in the method of raising the temperature of the ink L by the ink temperature adjuster 124, it is sufficient to deaerate at a temperature higher than the temperature to be circulated through the supply path 30, so that the ink L is circulated at a low temperature after deaeration at room temperature. After deaeration at a high temperature after raising the temperature to high temperature, it may be circulated at any temperature of 1) normal temperature, 2) temperature lower than normal temperature, and 3) temperature higher than normal temperature (temperature lower than high temperature).

10 Inkjet recording device (an example of a droplet discharge device)
30 Supply path 50 Head module (an example of a droplet discharge unit)
58 Supply side manifold (example of common flow path)
62 Supply-side branch (an example of an individual flow path)
68 Supply side valve (an example of shut-off means)
114 Deaeration module (an example of means for enhancing dissolution capacity)
115 Vacuum pump (an example of dissolution capacity enhancing means and decompression means)
118 Supply side pump (an example of supply means)
124 ink temperature controller (an example of temperature changing means)
202 Microcomputer (an example of control means)
214 Dissolving capacity control unit (an example of melting capacity enhancing means and temperature changing means)
L ink (example of liquid)
LA ink droplet (an example of a droplet)

Claims (5)

A droplet discharge section for discharging droplets;
A supply path through which the liquid supplied to the droplet discharge section flows;
Supply means for supplying a liquid to the droplet discharge section via the supply path;
Dissolution ability enhancing means for enhancing gas dissolution ability, which is provided in the supply path and represents the ability to dissolve bubbles in the liquid as compared with the normal time when the droplet discharge unit discharges droplets;
Control means for controlling the liquid dissolving ability to flow through the supply path when the liquid droplet discharge section does not discharge liquid droplets;
A droplet discharge device having The supply path includes a common flow path, a plurality of individual flow paths connected to the common flow path and connected to the plurality of droplet discharge units, and a blocking unit that blocks a flow of liquid in the individual flow paths. And provided,
The control means uses the blocking means to block the flow of liquid to the individual flow path by the blocking means and enhance the gas dissolving capacity by the dissolving capacity enhancing means while flowing the liquid to the common flow path. 2. The droplet discharge device according to claim 1, wherein the liquid droplet ejection device is controlled so as to release the blocking and to flow the liquid with enhanced gas dissolving ability through the common flow path and the individual flow paths.   3. The droplet discharge device according to claim 1, wherein the dissolution capacity enhancement unit includes a decompression unit that decompresses the liquid, and decompresses the pressure of the liquid more than the normal time.   The droplet discharge apparatus according to claim 3, wherein the dissolution capacity enhancing unit operates the supply unit so that the flow rate of the liquid is lower than that in the normal time when the decompression unit is decompressed.   5. The droplet discharge device according to claim 1, wherein the melting capacity enhancing unit includes a temperature changing unit that raises and lowers the temperature of the liquid. 6.